U.S. patent application number 09/906237 was filed with the patent office on 2002-05-02 for hydrothermally stable high pore volume aluminum oxide/swellable clay composites and methods of their preparation and use.
Invention is credited to Lussier, Roger Jean, Plecha, Stanislaw, Wear, Charles Cross, Weatherbee, Gordon Dean.
Application Number | 20020051878 09/906237 |
Document ID | / |
Family ID | 23917223 |
Filed Date | 2002-05-02 |
United States Patent
Application |
20020051878 |
Kind Code |
A1 |
Lussier, Roger Jean ; et
al. |
May 2, 2002 |
Hydrothermally stable high pore volume aluminum oxide/swellable
clay composites and methods of their preparation and use
Abstract
Porous composite particles are provided which comprise an
aluminum oxide component. e.g., crystalline boehmite, and a
swellable clay component, e.g., synthetic hectorite, intimately
dispersed within the aluminum oxide component at an amount
effective to increase the hydrothermal stability, pore volume,
and/or the mesopore pore mode of the composite particles relative
to the absence of the swellable clay. Also provided is a method for
making the composite particles, agglomerate particles derived
therefrom, and a process for hydroprocessing petroleum feedstock
using the agglomerates to support a hydroprocessing catalyst.
Inventors: |
Lussier, Roger Jean;
(Ellicott City, MD) ; Plecha, Stanislaw;
(Columbia, MD) ; Wear, Charles Cross; (Severna
Park, MD) ; Weatherbee, Gordon Dean; (Laurel,
MD) |
Correspondence
Address: |
Robert A. Maggio
W. R. Grace & Co.-Conn.
Patent Dept.
7500 Grace Drive
Columbia
MD
21044-4098
US
|
Family ID: |
23917223 |
Appl. No.: |
09/906237 |
Filed: |
July 16, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09906237 |
Jul 16, 2001 |
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09482734 |
Jan 13, 2000 |
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6303531 |
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Current U.S.
Class: |
428/325 ;
208/213; 208/216R; 208/217; 208/251H; 208/254H; 428/332; 502/63;
502/72; 585/275 |
Current CPC
Class: |
C01P 2006/10 20130101;
C01P 2006/12 20130101; B01J 35/1047 20130101; B01J 35/0026
20130101; B01J 21/04 20130101; B01J 35/1042 20130101; C01P 2006/14
20130101; B01J 37/0036 20130101; C01P 2006/13 20130101; C01P
2006/16 20130101; B01J 35/1061 20130101; B01J 35/002 20130101; Y10T
428/26 20150115; B01J 35/109 20130101; C01F 7/021 20130101; B01J
21/16 20130101; B01J 35/1019 20130101; B01J 35/108 20130101; Y10T
428/252 20150115 |
Class at
Publication: |
428/325 ;
208/213; 208/216.00R; 208/217; 208/251.00H; 208/254.00H; 502/63;
502/72; 585/275; 428/332 |
International
Class: |
C10G 045/04; B01J
021/16 |
Claims
What is claimed is:
1. Porous composite particles comprising an aluminum oxide
component and a swellable clay component intimately dispersed
within the aluminum oxide component, wherein in said composite
particles: (A) the alumina oxide component comprises at least 75
wt. % alumina, at least 5 wt. % of which alumina is in the form of
crystalline boehmite, gamma alumina derived from the crystalline
boehmite, or mixtures thereof, (B) the swellable clay component is
dispersible prior to incorporation into the composite particle and
present in the composite particles at an amount (i) of less than 10
wt. %, based on the combined weight of the aluminum oxide component
and the swellable clay component, and (ii) effective to increase at
least one of the hydrothermal stability, nitrogen pore volume, and
nitrogen mesopore pore mode of the composite particles relative to
the corresponding hydrothermal stability, pore volume and mesopore
pore mode of the aluminum oxide component in the absence of said
swellable clay; and (C) the average particle diameter of the
composite particles is from about 1 to about 150 microns.
2. The porous composite particles of claim 1 which, when calcined
at 537.8.degree. C. for 2 hours, have: (i) a specific surface area
of at least about 200 m.sup.2/g; (ii) an average nitrogen pore
diameter of from about 60 to 400 Angstroms; and (iii) a total
nitrogen pore volume of from about 0.5 to about 2.0 cc/g.
3. The porous composite particles of claim 1 wherein the aluminum
oxide component is derived from rehydrated active alumina, and the
swellable clay component is present in the composite at from about
1 to about 9 wt. % based on the combined weight of the swellable
clay component and aluminum oxide component.
4. The porous composite particles of claim 3 wherein the swellable
clay component comprises smectite clay.
5. The porous composite particles of claim 4 wherein the smectite
clay is selected from the group consisting of montmorillonite,
hectorite, and saponite.
6. The porous composite particles of claim 5 wherein the smectite
is a natural or synthetic hectorite.
7. The porous composite particles of claim 6 wherein the smectite
is a synthetic hectorite.
8. The porous composite particles of any one of claims 4 to 7
wherein the swellable clay component is present at from about 2 to
about 7 wt. % based on the combined weight of the aluminum oxide
and swellable clay components.
9. The porous composite particles of claim 2 having an average
nitrogen pore diameter of from about 70 to about 275 Angstroms, a
surface area of from about 240 to about 350 m.sup.2/g, a total
nitrogen pore volume of from about 0.6 to about 1.8 cc/g, and a
nitrogen mesopore pore mode of from about 60 to about 300
Angstroms.
10. The porous composite particles of claim 1 which additionally
comprise from about 0.1 to about 40 wt. % silicate based on the
combined weight of silicate, aluminum oxide component and swellable
clay component.
11. Porous composite particles comprising an aluminum oxide
component and a swellable clay component intimately dispersed
within the aluminum oxide component and which, when calcined of
537.8.degree. C. for 2 hours have: (A) a specific surface area of
at least about 200 m.sup.2/g; (B) an average nitrogen pore diameter
of from about 60 to 300 Angstroms; (C) a total nitrogen pore volume
of from about 0.5 to about 2.0 cc/g and characterized as having (i)
a macropore content of not greater than about 40% of the total pore
volume: (ii) a mesopore content of from about 20 to about 90% of
the total nitrogen pore volume and wherein at least about 40% of
the pores in the mesopore region have a diameter of from about 100
to about 400 Angstroms: and (iii) a micropore content of not
greater than about 80% of the total nitrogen pore volume; and
wherein in said composite particles: (i) the aluminum oxide
component comprises at least 75 wt. % alumina, at least 5 wt. % of
which alumina is in the form of crystalline boehmite, gamma alumina
derived from the crystalline boehmite, or mixtures thereof, (ii)
the swellable clay component is dispersible in water prior to
incorporation into the composite particle and present in the
composite particle at an amount (a) of less than 10 wt. %, based on
the combined weight of the aluminum oxide component and the
swellable clay component and (b) effective to increase at least one
of the hydrothermal stability, nitrogen pore volume, and the
nitrogen mesopore pore mode of the composite particles relative to
the corresponding hydrothermal stability pore volume and mesopore
pore mode of the aluminum oxide component in the absence of said
swellable clay and (iii) the average particle diameter of the
composite particles is from about 1 to about 150 microns.
12. A method for making porous composite particles comprising: (A)
forming a non-colloidal dispersion comprising at least one aluminum
oxide component-comprising at least 75 wt. % active alumina, and at
least one swellable clay component in a liquid dispersing medium;
(B) rehydrating the active alumina of the aluminum oxide component
in the presence of said dispersed swellable clay to convert at
least 5 wt. % of the active alumina to crystalline boehmite and to
form composite particles comprising an effective amount of
swellable clay intimately dispersed within the aluminum oxide
component, said effective amount of swellable clay being (i) less
than 10 wt. % based on the combined weight of the aluminum oxide
component and swellable clay component, and (ii) sufficient to
provide an increase in at least one of the hydrothermal stability,
nitrogen pore volume, and nitrogen mesopore pore mode of the
composite particles relative to the corresponding hydrothermal
stability, pore volume and mesopore pore mode of the aluminum oxide
component in the absence of said swellable clay; and (C) recovering
the composite particles from the dispersion; and (D) optionally
calcining the recovered composite particles at a temperature of
from about 250 to about 1000.degree. C. for a period of from about
0.15 to about 3 hours.
13. The process of claim 12 wherein the aluminum oxide component of
(A) comprises at least 90 wt. % alumina derived from the
rehydration of active alumina, the swellable clay component
comprises at least one smectite clay present in the dispersion at
from about 1 to about 8 wt. % based on the combined weight of
aluminum oxide component and swellable clay component, rehydration
is controlled to convert from about 30 to about 100 wt. % of the
active alumina to crystalline boehmite, having a crystallite size
of less than about 110 Angstroms and the liquid dispersing medium
is water.
14. The process of claim 13 wherein the smectite clay is selected
from the group consisting of montmorillonite, hectorite and
saponite.
15. The process of claim 14 wherein the smectite is a natural or
synthetic hectorite.
16. The process of claim 15 wherein the hectorite is at least one
synthetic hectorite present in the dispersion at an amount of from
about 3 to about 6 wt. %.
17. The process of claim 16 wherein the synthetic hectorite has a
total volatiles content of from about 6 to about 30 wt. %.
18. The process of claim 17 wherein the swellable clay component is
premilled prior to contact with the aluminum oxide component.
19. The process of claim 13 wherein the aluminum oxide component is
premilled prior to contact with the swellable clay component.
20. The process of claim 13 wherein from about 0.1 to about 40 wt.
% silicate, based on the combined weight of silicate, aluminum
oxide component, and swellable clay component, is provided to the
dispersion after rehydration of the active alumina to improve
hydrothermal stability of the composite particles.
21. The process of claim 13 wherein the swellable clay component
and aluminum oxide components are premilled in admixture prior to
rehydration of the active alumina.
22. Porous agglomerate particles comprising constituent composite
particles of a swellable clay component intimately dispersed within
an aluminum oxide component, wherein: (A) the agglomerate particle
size is from about 0.5 to about 5mm: (B) the aluminum oxide
component comprises at least 75 wt. % rehydrated active alumina, at
least 3.75 wt. % of which alumina oxide component is in the form of
crystalline boehmite, gamma alumina derived from the crystalline
boehmite, or mixtures thereof; and (C) the swellable clay component
is present within the aluminum oxide component in an amount (i) of
less than 10 wt. %, based on the combined weight of the aluminum
oxide and swellable clay components, and (ii) effective to increase
at least one of the hydrothermal stability, mercury pore volume and
mercury mesopore pore mode of the agglomerate particles relative to
the corresponding hydrothermal stability, pore volume and mesopore
pore mode of the agglomerate particles in the absence of the
swellable clay.
23. The porous agglomerate particles of claim 22 wherein the
support agglomerate particles, when calcined at 537.8.degree. C.
for 2 hours, possess: (i) a specific surface area of at least about
200 m.sup.2/g; (ii) a mercury mesopore pore mode of from about 60
to about 400 Angstroms: and (iii) a total mercury pore volume of
from about 0.6 to about 1.5 cc/g.
24. The porous agglomerate particles of claim 22 wherein the
aluminum oxide component comprises at least 7.5 wt. % crystalline
boehmite, gamma alumina derived from the crystalline boehmite, or
mixtures thereof, and the swellable clay component is present in
the agglomerate constituent particles at from about 2 to about 7
wt. %.,based on the combined weight of the swellable clay component
and aluminum oxide component.
25. The porous agglomerate particles of claim 24 wherein the
swellable clay component comprises smectite clay.
26. The porous agglomerate particles of claim 25 wherein the
smectite clay is selected from at least one member of the group of
montmorillonite, hectorite, and saponite.
27. The porous agglomerate particles of claim 26 wherein the
smectite is a natural or synthetic hectorite or mixtures
thereof.
28. The porous agglomerate particles of claim 27 wherein the
smectite is a synthetic hectorite.
29. The porous agglomerate particles of claim 28 wherein the
swellable clay component is present therein at from about 3 to
about 6 wt. % based on the combined weight of the aluminum oxide
and swellable clay components.
30. The porous agglomerate particles of claim 23, wherein the
surface area is from about 150 to about 350 m.sup.2/g, the total
mercury pore volume is from about 0.6 to about 1.5 cc/g, and the
mercury mesopore pore mode is from about 65 to about 275
Angstroms.
31. The porous agglomerate particles of claim 22 which additionally
comprise from about 2 to about 10 wt. % silicate, based on the
combined weight of silicate, alumina oxide component, and swellable
clay component, intimately dispersed within the constituent
particles.
32. The agglomerate particles of any one of claims 22 to 31
impregnated with an amount of at least one catalyst component
effective to hydroprocess petroleum feedstock.
33. The agglomerate particles of anyone of claims 22 to 31
impregnated with at least one hydrogenation component of a metal
having hydrogenation activitv selected from the group consisting of
Group VIII and Group VIA metals of the Periodic Table.
34. In a process for the hydroprocessing of petroleum feedstock
wherein said feedstock is contacted with hydrogen under pressure in
the presence of a supported hydroprocessing catalyst, the
improvement comprising utilizing porous agglomerate particles as
the support for the supported catalyst wherein said porous
agglomerate particles comprise constituent composite particles of a
swellable clay component intimately dispersed within an aluminum
oxide component wherein: (A) the agglomerate particle size is from
about 0.5 to about 5mm, (B) the aluminum oxide component comprises
at least 75 wt. % alumina, at least 3.75 wt. % of which aluminum
oxide component is in the form of crystalline boehmite, gamma
alumina derived from the crystalline boehmite, or mixtures thereof,
and (C) the swellable clay component is present within the aluminum
oxide component at an amount (i) of less than 10 wt. %, based on
the combined weight of the aluminum oxide and swellable clay
components, and (ii) effective to increase at least one of the
hydrothermal stability, mercury pore volume, and the mercury
mesopore pore mode of the agglomerate particles relative to the
corresponding hydrothermal stability, pore volume and mesopore pore
mode of the agglomerate particles in the absence of the swellable
clay.
35. The process of claim 34 wherein the support agglomerate
particles possess: (i) a specific surface area of at least about
200 m.sup.2/g; (ii) a mesopore mercury pore mode of from about 60
to about 400 Angstroms; and (iii) a total mercury pore volume of
from about 0.5 to about 1.8 cc/g.
36. The process of claim 34 wherein in the porous agglomerate
particles, the aluminum oxide component comprises at least 90 wt. %
rehydrated active alumina at least 7.5% of which aluminum oxide
component is in the form of crystalline boehmite, gamma alumina
derived from the crystalline boehmite, or mixtures thereof and the
swellable clay component is present in the agglomerate constituent
particles at from about 1 to about 8 wt. %, based on the combined
weight of the swellable clay component and aluminum oxide
component.
37. The process of claim 34 wherein in the porous agglomerate
particles, the swellable clay component comprises smectite
clay.
38. The process of claim 37 wherein in the porous agglomerate
particles, the smectite clay is selected from the group consisting
of montmorillonite, hectorite, and saponite.
39. The process of claim 38 wherein in the porous agglomerate
particles the smectite is a natural or synthetic hectorite.
40. The process of claim 39 wherein in the porous agglomerate
particles, the smectite is a synthetic hectorite.
41. The process of claim 40 wherein in the porous agglomerate
particles, the swellable clay component is present therein at from
about 2 to about 7 wt.% based on the combined weight of the
aluminum oxide and swellable clay components.
42. The process of claim 34 wherein the porous agglomerate
particles when calcined at 537.8.degree. C. for 2 hours, have a
mesopore mercury pore mode of from about 70 to about 250 Angstroms,
a mercury surface area of from about 200 to about 350 m.sup.2/g,
and a total mercury pore volume of from about 0.6 to about 1.5
cc/g.
43. The process of claim 34 wherein the porous agglomerate
particles additionally contain from about 2 to about 100 wt. %
silicate based on the combined weight of silicate, aluminum oxide
component, and swellable clay component, intimately dispersed
within the constituent particles.
44. The process of claim 34 wherein the catalyst supported on the
agglomerate particles is at least one hydrogenation component of a
metal having hydrogenation activity selected from the group
consisting of Group VIII and Group VIA metals of the Periodic
Table.
45. The process of claim 34 which is conducted in at least one
ebullating bed reactor.
46. Porous composite particles comprising an aluminum oxide
component and a swellable clay component intimately dispersed
within the aluminum oxide component, which, when calcined at
537.8.degree. C. for 2 hours, have: (A) a specific nitrogen surface
area of at least about 200 m.sup.2/g; (B) an average nitrogen pore
diameter of from about 60 to 300 Angstroms; and (C) a total
nitrogen pore volume of from about 0.5 to about 2.0 cc/g; and
prepared by the process comprising: (i) forming a non-colloidal
dispersion comprising at least one aluminum oxide component
comprising at least 75 wt. % active alumina, and at least one
swellable clay component in a liquid dispersing medium; (ii)
rehydrating the active alumina of the aluminum oxide component in
the presence of said dispersed swellable clay to convert at least 5
wt. % of the active alumina to crystalline boehmite and to form
composite particles comprising an effective amount of swellable
clay intimately dispersed within the aluminum oxide component, said
effective amount of swellable clay being (i) less than about 10 wt.
%, based on the combined weight of the aluminum oxide component and
swellable clay component, and (ii) sufficient to provide an
increase in at least one of the hydrothermal stability, nitrogen
pore volume and nitrogen mesopore pore mode of the composite
particles relative to the corresponding hydrothermal stability,
pore volume and mesopore pore mode of the aluminum oxide component
in the absence of said swellable clay; (iii) recovering the
composite particles from the dispersion.
47. The porous composite particles of claim 46 prepared by the
additional step of calcining the recovered composite particles at a
temperature of from about 250 to about 1000.degree. C. for a time
of from about 0.15 to about 3 hours.
Description
FIELD OF THE INVENTION
[0001] This invention relates to high pore volume aluminum oxide
composite particles, methods of their production, agglomerates and
supported catalysts derived therefrom, and methods of using said
catalysts.
BACKGROUND OF THE INVENTION
[0002] The art relating to particulate porous alumina particles,
shaped catalyst supports derived therefrom, supports impregnated
with various catalytically active metals, metal compounds and/or
promoters, and various uses of such impregnated supports as
catalysts, is extensive and relatively well developed.
[0003] While the prior art shows a continuous modification and
refinement of such particles, supports, and catalysts to improve
their catalytic activity, and while in some cases highly desirable
activities have actually been achieved, there is a continuing need
in the industry for improved catalyst supports and catalysts
derived therefrom. which have enhanced activity and life mediated
through a desirable balance of morphological properties.
[0004] Alumina is useful for a variety of applications including
catalyst supports and catalysts for chemical processes, catalyst
linings for automotive mufflers. and the like. In many of these
uses it will be desirable to add catalytic materials, such as
metallic ions, finely-divided metals, cations, and the like, to the
alumina. The level and distribution of these metals on the support,
as well as the properties of the support itself are key parameters
that influence the complex nature of catalytic activity and
life.
[0005] Alumina useful in catalytic applications has been produced
heretofore by a variety of processes, such as the water hydrolysis
of aluminum alkoxides, precipitation of alumina from alum, sodium
aluminate processes, and the like. High costs arise from the latter
two methods because the quantity of by-products, such as sodium
sulfate, actually exceed the quantity of desired product obtained,
i.e., boehmite. Typically, the cost of boehmite will be 4 times as
expensive as active alumina.
[0006] Generally speaking, while alumina from these sources can be
used for catalyst supports, such use is subject to certain
limitations. This stems from the fact that for supported catalysts
used in chemical reactions, the morphological properties of the
support, such as surface area, pore volume, and pore size
distribution of the pores that comprise the total pore volume are
very important. Such properties are instrumental in influencing the
nature and concentration of active catalytic sites, the diffusion
of the reactants to the active catalyst site, the diffusion of
products from the active sites, and catalyst life.
[0007] In addition, the support and its dimensions also influence
the mechanical strength, density and reactor packing
characteristics, all of which are important in commercial
applications.
[0008] Hydroprocessing catalysts in petroleum refining represent a
large segment of alumina-supported catalysts in commercial use.
Hydroprocessing applications span a wide range of feed types and
operating conditions, but have one or more of common objectives,
namely, removal of heteroatom impurities (sulfur, nitrogen, oxygen,
metals), increasing the H/C ratio in the products (thereby reducing
aromatics, density and/or carbon residues), and cracking carbon
bonds to reduce boiling range and average molecular weight.
[0009] More particularly, the use of a series of ebullated bed
reactors containing a catalyst having improved effectiveness and
activity maintenance in the desulfurization and demetallation of
metal-containing heavy hydrocarbon streams are well known.
[0010] As refiners increase the proportion of heavier, poorer
quality crude oil in the feedstock to be processed, the need grows
for processes to treat the fractions containing increasingly higher
levels of metals, asphaltenes, and sulfur.
[0011] It is widely known that various organometallic compounds and
asphaltenes are present in petroleum crude oils and other heavy
petroleum hydrocarbon streams, such as petroleum hydrocarbon
residua, hydrocarbon streams derived from tar sands, and
hydrocarbon streams derived from coals. The most common metals
found in such hydrocarbon streams are nickel, vanadium, and iron.
Such metals are very harmful to various petroleum refining
operations, such as hydrocracking, hydrodesulfurization. and
catalytic cracking. The metals and asphaltenes cause interstitial
plugging of the catalyst bed and reduced catalyst life. The various
metal deposits on a catalyst tend to poison or deactivate the
catalyst. Moreover, the asphaltenes tend to reduce the
susceptibility of the hydrocarbons to desulfurization. If a
catalyst, such as a desulfurization catalyst or a fluidized
cracking catalyst, is exposed to a hydrocarbon fraction that
contains metals and asphaltenes, the catalyst will become
deactivated rapidly and will be subject to premature
replacement.
[0012] Although processes for the hydrotreating of heavy
hydrocarbon streams, including but not limited to heavy crudes,
reduced crudes, and petroleum hydrocarbon residua, are known, the
use of fixed-bed catalytic processes to convert such feedstocks
without appreciable asphaltene precipitation and reactor plugging
and with effective removal of metals and other contaminants, such
as sulfur compounds and nitrogen compounds, are not common because
the catalysts employed have not generally been capable of
maintaining activity and performance.
[0013] Thus, certain hydroconversion processes are most effectively
carried out in an ebullated bed system. In an ebullated bed,
preheated hydrogen and resid enter the bottom of a reactor wherein
the upward flow of resid plus an internal recycle suspend the
catalyst particles in the liquid phase. Recent developments
involved the use of a powdered catalyst which can be suspended
without the need for a liquid recycle. In this system, part of the
catalyst is continuously or intermittently removed in a series of
cyclones and fresh catalyst is added to maintain activity. Roughly
about 1 wt. % of the catalyst inventory is replaced each day in an
ebullated bed system. Thus, the overall system activity is the
weighted average activity of catalyst varying from fresh to very
old i.e., deactivated.
[0014] In general, it is desirable to design the catalyst for the
highest surface area possible in order to provide the maximum
concentration of catalytic sites and activity. However, surface
area and pore diameter are inversely related within practical
limits. Sufficiently large pores are required for diffusion as the
catalyst ages and fouls, but large pores have a lower surface
area.
[0015] More specifically, the formulator is faced with competing
considerations which often dictate the balance of morphological
properties sought to be imparted to supports or catalysts derived
therefrom.
[0016] For example, it is recognized (see for example. U.S. Pat.
No. 4,497,909) that while pores having a diameter below 60
Angstroms (within the range of what is referred to herein as the
micropore region) have the effect of increasing the number of
active sites of certain silica/alumina hydrogenation catalysts,
these very same sites are the first ones clogged by coke thereby
causing a reduction in activity. Similarly, it is further
recognized that when such catalysts have more than 10% of the total
pore volume occupied by pores having a pore diameter greater than
600 Angstroms (within the region referred to herein generally as
the macropore region), the mechanical crush strength is lowered as
is the catalyst activity. Finally, it is recognized, for certain
silica/alumina catalysts, that maximization of pores having a pore
diameter between 150 and 600 Angstroms (approximately within the
region referred to herein as the mesopore region) is desirable for
acceptable activity and catalyst life.
[0017] Thus, while increasing the surface area of the catalyst will
increase the number of the active sites, such surface area increase
naturally results in an increase in the proportion of pores in the
micropore region. As indicated above, micropores are easily clogged
by coke. In short, increases in surface area and maximization of
mesopores are antagonistic properties.
[0018] Moreover, not only must the surface area be high, but it
should also remain stable when exposed to conversion conditions
such as high temperature and moisture. There has therefore been a
continuing search for high pore volume, high surface area,
hydrothermally stable alumina suitable for catalyst supports. The
present invention was developed in response to this search.
[0019] U.S. Pat. No. 4,981,825 is directed to compositions of
inorganic metal oxide (e.g., SiO.sub.2) and clay particles wherein
the oxide particles are substantially segregated from each other by
the clay particles. Suitable clays include Laponite". The disclosed
ratio of metal oxide:clay is between 1:1 to 20:1 (preferably 4:1 to
10:1). The subject composition is derived from an inorganic oxide
sol having a particle size of 40 to 800 Angstroms (0.004 to 0.08
microns). The particle size of the final product is dependent on
the size of the particles in the starting sol, although the final
particle size is unreported. It is critical that the metal oxide
and clay particles have opposite charges so that they will be
attracted to each other such that the clay particles inhibit
aggregation of the metal oxide particles. Thus, the clay particles
are described as being placed between the sol particles. Control of
the charges on the two different types of particles is determined
by the pH of the sol. The pH of the inorganic oxide is controlled
to be below its isoelectric point by acid addition thereby inducing
a positive charge on the inorganic oxide particles. While suitable
inorganic metal oxides are disclosed to also include
Al.sub.2O.sub.3, no examples of carrying out the invention using
Al.sub.2O.sub.3 are provided. Consequently, translating this
concept to Al.sub.2O.sub.3 is not without difficulty. For example,
the isoelectric point of Al.sub.2O.sub.3 is at a basic pH of about
9. However,. Al.sub.2O.sub.3 sols only form at a low pH of less
than about 5. If the pH exceeds about 5, an Al.sub.2O.sub.3 sol
will precipitate from dispersion or never form in the first place.
In contrast, SiO.sub.2 sols do not have to be acidic. Consequently,
while any point below the isoelectric point is acceptable for
SiO.sub.2 sols, the same is not true of Al.sub.2O.sub.3 sols.
Rather, one must operate at a pH well below the isoelectric point
of the Al.sub.2O.sub.3 in the pH region where alumina sols form.
Moreover, this patent discloses nothing about the pore properties
of the resulting composite and its thrust is only directed toward
obtaining high surface area. As indicated above, surface area and
high mesopore pore volume are typically antagonistic
properties.
[0020] In contrast, the presently claimed invention neither starts
with an Al.sub.2O.sub.3 sol nor forms a sot during rehydration. The
pH at which the presently claimed composites are formed is too high
for a sol to form during rehydration and the starting alunina
particles are too big for a sol to form initially.
[0021] Another area of technology relating to combinations of
various clay and metal oxides is known as intercalated clays.
Intercalated clays are represented by U.S. Pat. Nos. 3,803,026;
3,887,454 (See also 3,844,978); 3,892,655 (See also 3,844,979);
4,637,992; 4,761,391 (See also 4,844,790); and 4,995,964.
Intercalated clay patents typically have in common the requirement
that large clay:sol ratios be employed. Intercalated clays
generally have most of their surface area in micropores unless
freeze-dried.
[0022] U.S. Pat. No. 3,803,026 discloses a hydrogel or hydrogel
slurry comprising water, a fluorine-containing component, and an
amorphous cogel comprising oxides or hydroxides of silicon and
aluminum. The amorphous cogel further comprises an oxide or
hydroxide of at least one element selected from magnesium, zinc,
boron, tin, titanium, zirconium, hafnium, thorium, lanthanum,
cerium, praseodymium, neodymium, and phosphorus, said amorphous
cogel being present in the hydrogel or hydrogel slurry at an amount
of from 5 to 50 wt. %. The slurry is subjected to a pH of 6 to 10
and conversion conditions create a substantial amount of
crystalline aluminosilicate mineral, preferably in intimate
admixture with a substantial amount of unreacted amorphous cogel.
The silica/alumina molar ratio is at least 3:1 and the resulting
material is referred to as a synthetic layered crystalline
clay-type aluminosilicate mineral and the unreacted amorphous
co-gel exists mostly as SiO.sub.2. At column 5, lines 39 et seq.,
it is disclosed that the resulting aluminosilicate can be broken
into particles, pulverized into a powder, the powder dispersed in a
hydrogel, or hydrogel slurry to which is added components selected
from precursor compounds of, inter-alia, alumina. The resulting
mixture is then dried and activated. Notwithstanding the above
disclosure, no specific examples employing a mixture of
silica-aluminate with alumina is disclosed. Consequently, neither
the starting alumina, the final alumina, nor the amounts employed
of each material are disclosed.
[0023] U.S. Pat. No. 3,887,454 (and its parent 3,844,978) discloses
a layered type dioctahedral, clay-like mineral (LDCM) composed of
silica, alumina, and having magnesia incorporated into its
structure in controlled amounts. Preferred clays are
montmorillonite and kaolin. At column 6, lines 24 et seq., it is
disclosed that the clay material can be combined generally with
inorganic oxide components such as, inter-alia, amorphous alumina.
In contrast, the presently claimed composite utilizes crystalline
boehmite alumina. Similar disclosures are found in U.S. Pat. Nos.
3,892,655; and 3,844,979, except that these latter patents are
directed to layer-type. trioctahedral, clay-like mineral containing
magnesia as a component thereof (LTCM) and illustrated with a
saponite type clay.
[0024] U.S. Pat. No. 4,637,992 is an intercalated clay patent which
employs colloidal suspension of inorganic oxides and adds a
swellable clay thereto. While specific ranges illustrating the
ratio of clay to inorganic oxide are not disclosed, it appears that
the final material is still referred to as being a clay based
substrate into which is incorporated the inorganic oxide.
Consequently, this suggests that the final material contains a
major amount of clay rather than a predominate amount of aluminum
oxide and very minor amounts of clay as in the present invention.
See for example, column 5, lines 46 et seq., of the '992
patent.
[0025] U.S. Pat. No. 4,844,790 (division of U.S. Pat. No.
4,761,391) is directed to a delaminated clay prepared by reacting a
swellable clay with a pillaring agent which includes alumina. The
ratio of clay to pillaring agent is 0.1:1 to 10:1. preferably
between 1:1 to 2:1. The primary thrust of the patent, however, is
clay containing alumina and not alumina containing less than 10 wt.
% clay. It is reasoned that the metal oxides prop apart the
platelets of the clay and impart acidity thereto which is
responsible for the catalytic activity of the delaminated clay. The
preferred clay is a Laponite.RTM..
[0026] U.S. Pat. No. 4,995,964, is directed to a product prepared
by intercalating expandable clay (hectorite, saponite,
montmorillonite) with oligimers derived from rare earth salts, and
in particular, trivalent rare earths, and polyvalent cations of
pillaring metals, such as Al.sup.+'. The aluminum oxide material is
an aluminum containing oligimer which is used in providing the
pillars of the expanded clays. The claimed invention does not use
or produce oligimers of aluminum hydroxy materials.
[0027] U.S. Pat. No. 4,375,406 discloses compositions containing
fibrous clays and precalcined oxides prepared by forming a fluid
suspension of the clay with the precalcined oxide, agitating the
suspension to form a codispersion, and shaping and drying the
codispersion. The ratio of fibrous formed clay to precalcined oxide
composition can vary from 20:1 to 1:5. These amounts are well above
the amounts of clay employed in the presently claimed invention.
Moreover, fibrous clay is not within the scope of the swellable
clays described herein.
[0028] A number of patents are directed to various types of alumina
and methods of making the same, namely. Re 29.605; SIR HI 98; and
U.S. Pat. Nos. 3,322,495; 3,417,028; 3,773,691; 3,850,849;
3,898,322; 3,974,099; 3,987,155; 4,045,331; 4,069,140; 4,073,718;
4,120,943; 4,175,118; 4,708,945; 5,032,379; and 5,266,300.
[0029] More specifically, U.S. Pat. No. 3,974,099 is directed to
silica/alumina hydrogels from sodium silicate and sodium aluminate
cogels. The essence of this invention is directed to the
precipitation of Al.sub.2O.sub.3 onto silica-alumina gel which
stabilizes the cracking sites to hydrothermal deactivation. (Column
2, lines 43 et seq.) The resulting material typically has about
38.6% alumina oxide when all the excess sodium aluminate is
removed. In contrast, the silica employed in the presently claimed
invention is an additive which coats the surface of the
alumina/clay composite particles since it is added after the
composite formation.
[0030] U.S. Pat. No. 4,073,718 discloses a catalyst base of alumina
stabilized with silica on which is deposited a cobalt or nickel
catalyst.
[0031] U.S. Pat. No. 4,708,945 discloses a cracking catalyst of
silica supported on boehmite-like surface by compositing particles
of porous boehmite and treating them with steam at greater than
500.degree. C. to cause silica to react with the boehmite. 10%
silica is usually used to achieve a surface monolayer of silica to
improve thermal stability.
[0032] U.S. Pat. No. 5,032,379 is directed to alumina having
greater than 0.4 cc/g pore volume and a pore diameter in the range
of 30 to 200 .ANG.. The alumina is prepared by mixing two different
types of rehydration bondable aluminas to produce a product having
a bimodal pore distribution.
[0033] U.S. Pat. No. 4,266,300 discloses an alumina support
prepared by mixing at least two finely divided aluminas, each of
which is characterized by at least one pore mode in at least one of
the ranges (i) 100,000 to 10,000 .ANG., (ii) 10,000 to 1,000 .ANG.,
(iii) 1,000 to 30 .ANG..
[0034] U.S. Pat. No. 4,791,090 discloses a catalyst support with a
bidispersed micropore size distribution. Column 4, lines 65,
discloses that two sizes of micropores can be formulated by mixing
completely different materials having different pore sizes such as
alumina and silica.
[0035] U.S. Pat. No. 4,497,909 is directed to silica/alumina
carriers having a silica content less than about 40% by weight and
at least one noble metal component of Group VII of the Periodic
Table and wherein the catalyst contains pores having a diameter
smaller than 600 .ANG. occupying at least 90% of the total pore
volume, and pores having a diameter of 150 to 600 .ANG. occupying
at least about 40% of the total pore volume made up of pores having
a diameter smaller than 600 .ANG..
[0036] The following patents disclose various types of clays: U.S.
Pat. Nos. 3,586,478; 4,049,780; 4,629,712; and PCT Publication Nos.
WO 93/11069; and WO 94/16996.
[0037] The following patents disclose various types of agglomerates
which can be formed from alumina: U.S. Pat. Nos. 3,392,125;
3,630,888; 3,975,510; 4,124,699; 4,76,201 (see also 4,309,278);
4,392,987; and 5,244,648.
[0038] U.S. Pat. No. 4,276,201 discloses a hydroprocessing catalyst
which utilizes an agglomerate support of alumina, e.g., beaded
alumina, and silica wherein the silica is less than 10 wt. % of the
support. The agglomerate support has a surface area of 350-500
m.sup.2/g. A total pore volume (TPV) of 1.0 to 2.5 cc/g with less
than 0.20 cc/g of the TPV residing in pores having a diameter
greater than 400 .ANG..
[0039] U.S. Pat. No. 5,114,895 discloses a composition of a layered
clay homogeneously dispersed in an inorganic oxide matrix such that
the clay layers are completely surrounded by the inorganic oxide
matrix. The inorganic oxide matrix is selected from alumina,
titania, silica, zirconia, P.sub.2O.sub.5 and mixtures. Suitable
clays include bentonite, sepiolite, Laponite.TM., vermiculite,
montmorillonite, kaolin, palygorskite (attapulgus), hectorite,
chlorite, beidellite, saponite, and nontronite. To get the clay
homogeneously dispersed within the inorganic oxide matrix, a
precursor of the inorganic oxide is dispersed as a sol or hydrosol
and gelled in the presence of the clay. While clay contents of 5 to
70 wt. % are disclosed broadly, the Examples employ at least 30 wt.
% clay. In addition, none of the pore properties or the resulting
product are disclosed.
[0040] U.S. Pat. No. 4,159,969 discloses a process for the
manufacture of agglomerates of aluminum oxide by contacting a
hydrous aluminum oxide gel with an organic liquid immiscible with
water wherein the amount of said liquid is a function of the water
in the hydrous aluminum oxide gel. An amount of clay, such as
bentonite or kaolin, sufficient to increase the strength of the
agglomerates may be added to the aluminum oxide during or after
gelation. No specific amount of clay is disclosed and kaolin is not
a swellable clay. None of the examples employ clay.
[0041] U.S. Pat. No. 3,630,888 discloses a catalyst having a
structure in which access channels having diameters between about
100 and 1000 .ANG. units constitute 10 to 40% of the total pore
volume and in which access channels having diameters greater than
1000 .ANG. units constitute between about 10 to about 40% of the
total pore volume, while the remainder of the pore volume comprises
20 to 80% of micropores with diameters less than 100 .ANG..
[0042] The following patents disclose various hydroprocessing
operations and use of catalysts therein: U.S. Pat. Nos. 3,887,455;
4,657,665; 4,886,594; PCT Publication No. WO 95/31280.
SUMMARY OF THE INVENTION
[0043] The present invention is based on the discovery that when
active alumina is dispersed and subjected to a rehydration process
in the presence of controlled amounts of a dispersed swellable
clay, the resulting composite particles exhibit and maintain high
surface area while simultaneously possessing a higher pore volume
and pore mode in the mesopore region relative to the absence of the
clay. These properties are substantially preserved in agglomerates,
e.g., shaped extrudates, derived from the composite particles
before and after impregnation with catalytically active metal
components such as those employed for hydroprocessing operations.
In addition, the incorporation of the swellable clay improves the
hydrothermal stability of the composite particles.
[0044] Improvements in hydrothermal stability improve the overall
economics of a process employing the same while shifts to higher
mesopore pore modes increase the activity of supported catalyst
derived from the composite particles. A higher pore mode improves
accessibility of the hydrocarbons and reduces the possibility of
the pores being plugged due to coke or metals deposition.
[0045] High pore volume aluminas are often prepared by azeotroping
with alcohols to remove the water before drying. The alcohol is
used to reduce the surface tension of the water which in turn
reduces the shrinkage of pores during drying. This technique is
very expensive and environmentally unfriendly. Aluminas with a high
average pore diameter (APD) are often prepared by sintering at high
temperatures. While sintering increases the APD of the unsintered
material, it necessarily decreases the surface area relative to the
unsintered material. Thus, one is forced to sacrifice surface area
in order to achieve the higher APD. It has been found that one can
not only shift the mesopore pore mode to larger pores prior to
sintering, but also it is believed that less shrinkage in pore
diameter will occur upon exposure to elevated temperatures(commonly
associated with sintering without clay). Thus, since one can start
with a higher pore mode, and less shrinkage occurs from that higher
pore mode, a high surface area, high pore volume product can be
obtained in a more cost efficient and environmentally friendly
manner, e.g., alcohol azeotroping can be eliminated, and the
temperatures to which the alumina would otherwise need to be heated
can be lowered.
[0046] Accordingly, in one aspect of the present invention there is
provided porous composite particles comprising an aluminum oxide
component and a swellable clay component intimately dispersed
within the aluminum oxide component wherein in said composite
particles:
[0047] (A) the alumina oxide component comprises at least 75 wt. %
alumina. at least 5 wt. % of which alumina is in the form of
crystalline boehmite, gamma alumina derived from the crystalline
boehmite, or mixtures thereof;
[0048] (B) the swellable clay component is dispersible prior to
incorporation into the composite particle and present in the
composite particles at an amount (a) of less than about 10 wt. %,
based on the combined weight of the aluminum oxide component and
the swellable clay component and (b) effective to increase at least
one of the hydrothermal stability, nitrogen pore volume, and
nitrogen mesopore pore mode of the composite particles relative to
the corresponding hydrothermal stability, pore volume and mesopore
pore mode, of the aluminum oxide component in the absence of said
swellable clay; and
[0049] (C) the average particle diameter of the composite particles
is from about 0.1 to about 100 microns.
[0050] In a further aspect of the present invention, there is
provided a process for making porous composite particles
comprising:
[0051] (A) forming a non-colloidal dispersion comprising at least
one aluminum oxide component comprising at least 75 wt. % active
alumina, and at least one swellable clay component in a liquid
dispersing medium;
[0052] (B) rehydrating the active alumina of the aluminum oxide
component in the presence of said dispersed swellable clay to
convert at least 5 wt. % of the active alumnina to crystalline
boehmite and to form composite particles comprising an effective
amount of swell able clay intimately dispersed within the aluminum
oxide component, said effective amount of swellable clay being (i)
less than 10 wt. %, based on the combined weight of the aluminum
oxide component and swellable clay component, and (ii) sufficient
to provide an increase in at least one of the hydrothermal
stability, nitrogen pore volume and nitrogen mesopore pore mode of
the composite particles relative to the corresponding hydrothermal
stability, pore volume, and mesopore pore mode, of the aluminum
oxide component in the absence of said swellable clay;
[0053] (C) recovering the composite particles from the dispersion;
and
[0054] (D) optionally calcining the recovered composite particles
at a temperature of from about 250 to about 1,0000.degree. C. for a
time of from about 0.15 to about 3 hours.
[0055] In another aspect of the present invention, there is
provided agglomerates of the above particles.
[0056] In a further aspect of the present invention, there is
provided supported catalysts derived from the above
agglomerates.
[0057] In a still further aspect of the present invention, there is
provided a process for hydroprocessing petroleum feedstock using
the above agglomerates as supports for hydroprocessing
catalysts.
BRIEF DESCRIPTION OF THE DRAWINGS
[0058] The following table summarizes FIGS. 1 to 24 which are plots
derived from the examples. The pertinent information about the
Figures including the corresponding Run Numbers, Example or
Comparative Example Number, the X-axis, Y-axis and plot legends are
provided in the following table:
1 Figure Summary Table Invention Disclosure Designation Attachment
Figure Ex or C No. or Orig No. Run Nos. Ex No. X-Axis Y-Axis Legend
Designations Ref. No. Figure No. 1 1-2 Ex. 1 N.sub.2 Pore Diameter
.ANG. dV/d Log D Run 1 (0% L) 9433 A-2 Run 2 (3 wt. % L) 2 3-5 Ex.
2 N.sub.2 Pore Diameter .ANG. dV/d Log D Run 3 (0% L) 9433 A-4 Run
4 (0.5 wt. % L) Run 5 (1 wt. % L) 3 3, 6, 7, 9, Ex. 2 N.sub.2 Pore
Diameter .ANG. dV/d Log D Run 3 (0% L) 9433 A-5 10 Run 6 (2 wt. %
L) Run 7 (3 wt. % L) --+-- Run 9 (5 wt. % L) Run 10 (6 wt. % L) 4
16-1 Ex. 4 N.sub.2 Pore Diameter .ANG. dV/d Log D Run 3 (0 wt % L)
16-2 Run 16-1 (3 wt. % SH-1) 9433 A-7 Run 16-2 (3 wt. % SH-2) 5
17-19 Ex. 5 N.sub.2 Pore Diameter .ANG. dV/d Log D Run 17 (0% L)
9433 A-8 Run 18 (4 wt. % NH-1) Run 19 (4 wt. % NH-2) 6 22-23 Ex. 6
wt. % L Steamed Run 22 (AP-15) 9433 A-10 SA (m.sup.2/g) Run 23
(CP-3) 7 24-25 Ex. 7 wt. % L Steamed Run 24 (Post hydration) 9433
A-11 SA (m.sup.2/g) Run 25 (Pre hydration) 8 26-28 Ex. 8 N.sub.2
Pore Diameter .ANG. dV/d Log D Run 26 (0% L) 9433 A-13 Run 27 (3
wt. % L) Run 28 (3 wt. % L + milling) 9 32, 34, 35 C. Ex. 2 Pore
Diameter .ANG. dV/d Log D Run 32 (0% Clay) 9433 A-16 Run 34 (6 wt.
% CK) Run 35 (12 wt. % CK) 10 32, 36, 37 Ex. 10 N.sub.2 Pore
Diameter .ANG. dV/d Log D Run 32 (0% Clay) 9433 A-17 Run 36 (6 wt.
% GL) Run 37 (12 wt. % GL) 11 32, 38, 39 Ex. 11 N.sub.2 Pore
Diameter .ANG. dV/d Log D Run 32 (0 wt. % Clay) 9433 A-18 Run 39
(0.5 wt. % SiO.sub.2) Run 38 (1 wt. % SiO.sub.2) 12 40-42 Ex. 12
Hrs @ 800.degree. C. in SA Run 40 (0 wt. % L) 9433 A-19 contact
with 20% Run 41 (3 wt. % L) steam Run 42 (3 wt. % L + milling) 13
40-42 Ex. 12 Hrs @ 800.degree. C. in % SA Retention Run 40 (0% L)
9433 A-20 contact with 20% Run 41 (3 wt. % L) steam Run 42 (3 wt. %
L + milling) 14 43-44 Ex. 13 Wt. % SiO.sub.2 Steamed SA Run 43
(boehmite from CP-3) 9434 A-1 added to boehmite Run 44 (boehmite
from AP-15) 15 45-46 Ex. 14 Wt. % SiO.sub.2 added Steamed SA Run 45
(3 wt % L) 9434 A-2 Run 46 (5 wt % L) 16 43-46 Ex. 14 Wt. %
SiO.sub.2 added Steamed SA Run 43 (0% Clay) 9434 A-3 Run 44 (0%
Clay) Run 45 (3 wt. % Clay) Run 46 (5 wt % Clay) 17 47-49 Ex. 15
Wt. % SiO.sub.2 added Steamed SA Run 47 (0% Clay) 9434 A-4 Run 48
(3 wt. % dispersed clay) Run 49 (3 wt % poorly dispersed clay) 18
53-55 Ex. 17 Wt. % SiO.sub.2 SA after 4 hours Run 53 (SiO.sub.2
After Age) 9434 A-6 @ 800.degree. C. Run 54 (SiO.sub.2 Before Age)
Run 55 (SiO.sub.2 After Age @ 3 wt. % L) 19 56-59 Ex. 18 N.sub.2
Pore Diameter .ANG. dV/d Log D Run 56 (0% SiO.sub.2) 9434 A-7 Run
57 (2 wt. % SiO.sub.2) Run 58 (4 wt. % SiO.sub.2) --+-- Run 59 (8
wt. % SiO.sub.2) 20 60-61 Ex. 19 Hg Pore Diameter .ANG. Hg dV/dLogD
---- Run 61 (CAX-1) 9450 - - - - Run 60 (AX-1) 21 62, 64, 66, Ex.
20 Hg Pore Diameter .ANG. dV/dLogD ---- Run 68 (EMCAX-1) 9450 68
Ex. 21 - - - - Run 62 (EMAX-1) C. Ex. 4 Run 64 (EMAX-2) ------ Run
66 (EMAX-3) 22 70-72 Ex. 23 Hg Pore Diameter .ANG. HgdV/dLogD --
Run 72 9450 Ex. 24 - - - - Run 71 C. Ex. 5 --.-- Run 70 23 76-77
Ex. 26 Catalyst Age, % Conversion .diamond-solid. Run 76 (EMAX-1)
9450 FIG. 9 1 C. Ex. 7 bbl/lb. .tangle-solidup. Run 77 (EMCAX-1) 24
78-80 Ex. 27 Catalyst Age, % Conversion .diamond-solid. Run 78
(EMAX-2) 9450 FIG. 10.1 Ex. 28 bbl/lb. .box-solid. Run 79 (EMAX-3)
C. Ex. 8 .oval-solid. Run 80 (EMCAX-1) dV/d log D = the
differential of the change in pore volume (cc/g) per change in the
differential of the Log of pore diameter L = Laponite .RTM.
(synthetic hectorite) CK = Calcined Kaolin GL =
Gelwhite-LMontmorillonite Clay SA = Surface Area
DESCRIPTION OF PREFERRED EMBODIMENTS
[0059] The term "micropore" as used herein means pores having a
diameter of less than 100 Angstroms.
[0060] The term "mesopore" as used herein means pores having a
diameter between 100 and 500 Angstroms.
[0061] The term "macropore" as used herein means pores having a
diameter greater than 500 Angstroms.
[0062] The term "pore mode" as used herein means the pore diameter
corresponding to the peak maximum where the log differential
nitrogen or mercury intrusion in cc/g. is plotted as a function of
the differential of the log of the pore diameter.
[0063] The term "total pore volume" as used herein means the
cumulative volume in cc/g of all pores discernable by either
nitrogen desorption or mercury penetration methods. More
specifically, for alumina particles which have not been
agglomerated (e.g., by extrusion) the pore diameter distribution
and pore volume is calculated with reference to the nitrogen
desorption isotherm (assuming cylindrical pores) by the B.E.T.
technique as described by S. Brunauer, P. Emmett, and E. Teller in
the Journal of American Chemical Society, 60, pp 209-319
(1939).
[0064] In respect to alumina particles which have been
agglomerated, e.g., formed into extrudates, the pore diameter
distribution is calculated by means of the formula: 1 Pore Diameter
( in Anstroms ) = 150 absolute mercury pressure ( in bar ) (
Equation 1 )
[0065] and in accordance with the mercury penetration method (as
described by H. L. Ritter and L. C. Drake in Industrial and
Engineering Chemistry, Analytical Edition 17, 787 (1945)), using
mercury pressures of 1-2000 bar. Surface Area for composite
particles as well as agglomerates is determined however by the
nitrogen desorption method.
[0066] The total N.sub.2 pore volume of a sample is the sum of the
nitrogen pore volumes as determined by the above described nitrogen
desorption method. Similarly, the total mercury pore volume of a
sample is the sum of the mercury pore volumes as determined by the
mercury penetration method described above using a contact angle of
130.degree., a surface tension of 485 dynes /cm and a Hg density of
13,5335 gm/cc.
[0067] All morphological properties involving weight, such as pore
volume (cc/g) or surface area (m.sup.2/g) are to be normalized to a
Metals Free Basis as defined in accordance with Equation 4
described in Example 20.
[0068] All fresh surface areas are determined on samples which have
been dried and then calcined in air at 537.8.degree. C. for 2
hours.
[0069] Bulk density is measured by quickly transferring (in 10
seconds) the sample powder into a graduated cylinder which
overflows when exactly 100 cc is reached. No further powder is
added at this point. The rate of powder addition prevents settling
within the cylinder. The weight of the powder is divided by 100 cc
to give the density.
[0070] All particle size and particle size distribution
measurements described herein are determined by a Mastersizer unit
from Malvern, which operates on the principle of laser light
diffraction and is known to all familiar in the art of small
particle analysis.
[0071] The aluminum oxide component which is mixed with the
swellable clay component comprises typically at least 75,
preferably at least 80 (e.g.. at least 85), most preferably at
least 90 (e.g., at least 95) wt. % active alumina which amounts can
vary typically from about 75 to 100, preferably from about 80 to
100, and most preferably from about 90 to 100 wt. % active alumina.
Active alumina can be prepared by a variety of methods. For
example, alumina trihydrate precipitated in the Bayer process may
be ground and flash calcined. Active alumina, as referred to
herein, is characterized as having a poorly crystalline and/or
amorphous structure.
[0072] The expression "alumina of poorly crystalline structure" for
the purposes of the aforegoing process is understood as meaning an
alumina which is such that X-ray analysis gives a pattern which
shows only one or a few diffuse lines corresponding to the
crystalline phases of the low-temperature transition aluminas, and
contains essentially the chi, rho, eta, gamma and pseudo-gamma
phases and mixtures thereof.
[0073] By the expression "alumina of amorphous structure" is meant
an alumina which is such that its X-ray analysis does not give any
line characteristic of a highly (predominantly) crystalline
phase.
[0074] Active alumina employed herein can be generally obtained by
the rapid dehydration of aluminum hydroxides such as bayerite,
hydrargillite or gibbsite, and nordstrandite, or of aluminum
oxyhydroxides such as boehmite and diaspore. The dehydration can be
carried out in any appropriate apparatus, and by using a hot
gaseous stream. The temperature at which the gases enter the
apparatus can generally vary from about 400.degree. to
1,200.degree. C. and the contact time of the hydroxide or
oxyhydroxide with the hot gases is generally between a fraction of
a second and 4 to 5 seconds.
[0075] The resulting product may contain minor, e.g., trace,
amounts of boehmite, gibbsite, gamma, alpha, delta and other
crystalline alumina structures.
[0076] The resulting active alumina will typically exhibit a weight
loss when heated to 538.degree. C. for 1 hour of from about 4 to 12
wt. %.
[0077] The specific surface area of the active alumina obtained by
the rapid dehydration of hydroxides or oxyhydroxides, as measured
by the conventional BET method, generally varies between about 50
and 400 m.sup.2/g, and the diameter of the particles is generally
between 0.1 and 300 microns and preferably between 1 and 120
microns with an average particle size of typically greater than 1
micron, preferably between about 5 and about 20, most preferably
between about 5 and about 15 microns. The loss on ignition,
measured by calcination at 1,000.degree. C., generally varies
between 3 and 15%, which corresponds to a molar ratio
H.sub.2O/Al.sub.2O.sub.3 of between about 0.17 and 1.0.
[0078] In a preferred embodiment, an active alumina originating
from the rapid dehydration of Bayer hydrate (gibbsite), which is a
readily available and inexpensive industrial aluminum hydroxide is
employed. Active alumina of this type is well known to those
skilled in the art and the process for its preparation has been
described, for example, in U.S. Pat. Nos. 2,915,365, 3,222,129;
4,579,839 and preferably 4,051,072, column 3, line 6, to column 4,
line 7, the disclosures of which patents are incorporated herein by
reference.
[0079] The active alumina employed can be used as such or may be
treated so that its sodium hydroxide content, expressed as
Na.sub.2O, is less than 1,000 ppm.
[0080] More specifically, the composite particles prepared with
silicate or certain clays such as synthetic hectorite will
typically contain Na.sub.2O, which can cause sintering of the
alumina at high temperatures. This sintering will reduce surface
area. To eliminate such sintering, the alumina is preferably washed
to remove the Na.sub.2O in the form of salts. Still, more
specifically, the alumina is preferably slurried in water
containing about 0.05 parts by weight ammonium sulfate (A/S), about
1 part by weight alumina, and 5 parts by weight water, for 15
minutes. The slurry is then filtered, washed at least one time with
water to remove salts and oven dried. This wash can be conducted
before or after contact with the clay or on any component which may
possess Na.sub.2O. The active alumina employed may or may not be
ground but it is preferred to be ground to facilitate dispersion in
or with the swellable clay slurry described hereinafter.
[0081] Suitable active alumina powder starting material is
commercially available from the Aluminum Company of America under
grade designations CP-3, CP-1, CP-5, CP-7, and CP-100 It is also
available from Porocel (Little Rock, Ark.) under the designation
AP-15.
[0082] All of the active aluminas suitable for use in the aluminum
oxide component of the present invention are rehydrateable and form
a hydroxyl bond upon contact with water. The present invention
draws a distinction between the phenomenon of rehydration, i.e.,
the chemical changes induced by subjecting the active alumina to
water and elevated temperatures, and the process of rehydration.
i.e., the process steps involved in inducing the phenomenon of
rehydration.
[0083] The phenomenon of rehydration is believed to represent the
chemical and physical state of that active alumina which has been
converted to crystalline boehlmite. However, the change in state
from active alumina to boehmite does not have to be complete with
reference to the entire sample being acted upon during the
rehydration process. For example, depending on the condition of the
rehydration process, it may be possible that only the outer shell
of an active alumina particle or filter cake is converted to
boehmite with the remaining inner portions thereof remaining as
either active alumina or some form of alumina other than boehmite
or active alumina. Thus, while "rehydrated alumina" is chemically
synonymous with boehmite; alumina derived from the rehydration of
active alumina includes boehmite, active alumina, and any alumina
by-products other than boehmite which might form during the
rehydration process. Similarly, the rehydration process refers to
the manipulative process steps involving the addition of active
alumina to water under conditions, e.g., elevated temperature,
described hereinafter.
[0084] The swellable clay component comprises any member of the 2:1
clay:mineral layered silicate clays capable of undergoing swelling
and dispersion and mixtures thereof. Swelling clays are expandable
clays whose platelets are held together by weak van der Waal's
forces and have a particular shape or morphology. Such clays
include the smectite class of clays as well as the ion exchanged
(e.g., Na.sup.+, Li.sup.+) derivatives thereof. In general, alkali
metal exchange forms are preferred because of their enhanced
ability to swell and disperse. Also, dispersible 2:1 layered
silicates such as tetrasilicic mica and taeniolite are useful.
[0085] More specifically, smectites are 2:1 clay mineral that carry
a lattice charge and characteristically expand when solvated with
water and alcohols, most notably ethylene glycol and glycerol.
These minerals comprise layers represented by the general
formula:
(M.sub.8).sup.IV(M.sup.'.sub.8).sup.VIO.sub.20(OH.F).sub.4
[0086] wherein IV indicates an ion coordinated to four other ions,
VI indicates an ion coordinated to six other ions and x may be 4 or
6. M is commonly Si.sup.4+, Al.sup.3+ and/or Fe.sup.3+, but also
includes several other four coordinate ions such as P.sup.5+,
B.sup.3+, Ge.sup.4+, Be.sup.2+, and the like. M.sup.+ is commonly
Al.sup.3+ or Mg.sup.2+, but also includes many possible
hexacoordinated ions such as Fe.sup.3+, Fe.sup.2-, Ni.sup.2-,
Co.sup.2-, Li.sup.+, and the like. The charge deficiencies created
by the various substitutions into these four and six coordinate
cation positions are balanced by one or several cations located
between the structural units. Water may also be occluded between
these structural units bonded either to the structure itself, or to
the cations as a hydration shell. When dehydrated (dehydroxylated),
the above structural units have a repeat distance of about 9 to 12
Angstroms, as measured by X-ray diffraction. Commercially available
natural smectites include montmorillonite (bentonite), beidellite,
hectorite, saponite, sauconite and nontronite. Also commercially
available are synthetic smectites such as LAPONITE.RTM., a
synthetic hectorite available from Laporte Industries Limited.
[0087] Smectites are classified into two categories, dioctahedral
and trioctahedral, the difference being the number of octahedral
sites in the central layer which are occupied. This, in turn, is
related to the valency of the cation in the central layers.
[0088] The dioctahedral smectites have central cations which are
trivalent and accordingly only two-thirds of the octahedral sites
are occupied, whereas trioctahedral smectites have divalent central
cations where all of the octahedral sites are occupied.
Dioctahedral smectites include montmorillonite, beidellite and
nontronite wherein, for example, montmorillonite has as the
octahedral cation (M'), aluminum, with other cations such as
magnesium also present. Trioctahedral smectites, which are
preferred, include hectorite and saponite and their synthetic forms
wherein, for example. hectorite has as the octahedral cation (M'),
magnesium, with lithium also present.
[0089] The smectite most advantageously used in the preparation of
the compositions of this invention is trioctahedral smectite clay
having a lath-shape morphology. However, trioctahedral smectites of
platety-shape or mixed lath-shape and platety-shape morphology can
be employed. Exemplary of suitable trioctahedral smectite clays are
natural saponite, and preferably, natural hectorite and synthetic
hectorite.
[0090] The most preferred swelling clay for use as the swellable
clay component are the synthetic hectorites. Procedures for
preparing synthetic hectorites are well known and are described for
example, in U.S. Pat. Nos. 3,803,026; 3,844,979; 3,887,454;
3,892,655 and 4,049,780, the disclosures of which is herein
incorporated by reference. A typical example of synthetic hectorite
is Laponite.RTM. RD. Laponite.RTM. RD clay is a filter pressed,
tray dried and pin milled product. The platelets of Laponite.RTM.
RD clay are composed of two silica layers surrounding a layer of
magnesium in octahedral coordination, with lithium substitution in
this layer. Laponite.RTM. RD clay and other Laponites are
manufactured and sold by Laporte Inorganics, a part of Laporte
Industries Limited. A typical analysis and the physical properties
of Laponite.RTM. RD clay are set forth below in Table 1.
2TABLE 1 Chemical Composition Laponite .RTM. RD Component Weight %
SiO.sub.2 59-60 MgO 27-29 Li.sub.2O 0.7-0.9 Na.sub.2O 2.2-3.5 Loss
of Ignition 8-10 Physical Properties Appearance white powder pH (2%
Suspension) 9.8 Bulk Density (kg/m.sup.2) 1000 Surface Area
(N.sub.2 adsorption) 370 m.sup.2/g Sieve Analysis % <250 microns
98 Moisture Content, Wt. % 10
[0091] In order to prepare the composite particles of the present
invention, non-colloidal active alumina is at least partially
rehydrated in the presence of the dispersed swellable clay.
[0092] Rehydration of the alumina will eventually naturally occur
at room temperature in the presence of water but would take an
extended amount of time. Rehydration is therefore preferably
conducted at elevated temperatures of at least about 50.degree. C.
to speed up the rehydration process. It is convenient to conduct
rehydration by simple refluxing of an aqueous slurry of the active
alumina for a period of typically from about 1 to about 72,
preferably from about 2 to about 48, and most preferably from about
3 to about 24 hours.
[0093] Rehydration conditions are controlled to obtain a high pore
volume product. Accordingly, rehydration conditions are controlled
such that typically at least 5, preferably at least 10, and most
preferably at least 15 wt. % of the active alumina is converted to
boehmite, and the boehmite content in the alumina derived from the
rehydration of active alumina can range typically from about 5 to
about 100 (e.g., 30 to 100), preferably from about 10 to about 100
(e.g., 50 to 100), most preferably from about 15 to about 100
(e.g., 75 to 100) wt. %, based on the weight of the alumina. An
undesirable by-product to boehmite formation is bayerite which is
an alumina trihydrate that forms if the pH of the water exceeds
about 10.
[0094] In view of the initial active alumina content in the
aluminum oxide component and the degree of conversion of active
alumina to crystalline boehmite, the aluminum oxide component of
the composite particles will desirably contain (A) typically at
least 75, preferably at least 80 (e.g., at least 85), and most
preferably at least 90 (e.g., at least 95) wt. % alumina,
preferably alumina derived from the rehydration of active alumina,
and (B) typically at least 3.75, and preferably at least 7.5, and
most preferably at least 10 wt. % of the aluminum oxide component
is crystalline boehmite, which amount of crystalline boehmite can
vary typically from about 3.75 to about 100 (e.g., 40-100),
preferably from about 7.5 to about 100 (e.g., 75-100), and most
preferably from about 10 to about 100 (e.g.. 90-100) wt. %, based
on the weight of the aluminum oxide component. Similarly, the
weight ratio of crystalline boehmite to swellable clay in the
composite particles will typically vary from about 4:1 to about
99:1, preferably from about 9:1 to about 50:1, and most preferably
from about 15:1 to about 50:1.
[0095] The crystallite size (as determined by the procedure
described at Example 1) will typically be less than about 110
(e.g., less than about 100) Angstroms and will range typically from
about 55 to about 110. preferably from about 60 to about 100, and
most preferably from about 65 to about 95 Angstroms.
[0096] Boehmite formation is maximized at a pH of about 9 (e.g., 7
to 10). Thus, a buffer, such as sodium gluconate, can be added to
stabilize the pH at about 9 but such an additive can have the
undesired effect of reducing the size of the boehmite crystallites
which in turn tends to lower the total pore volume. Thus, it is
preferred not to employ a buffer. In fact, one of the advantages of
the swellable clay is that it is a natural buffer at a pH of about
9 and inhibits rehydration to Bayerite.
[0097] As indicated above, the rehydration of the active alumina in
the aluminum oxide component must occur in the presence of the
dispersed swellable clay. Without wishing to be bound to any
particular theory, it is believed that the highly dispersed
swellable clay becomes entrapped within the growing boehmite
crystals and creates intercrystalline voids by propping the
crystallites apart, thereby increasing the pore volume without
decreasing surface area. It is believed to be for this reason that
the smaller the swellable clay particle size and the higher the
degree of dispersion of the clay particles in the slurry, the
greater will be the shift of the pore mode in the mesopore region
of the composite particles. The rehydration of the alumina neither
starts with an alumina sol nor converts the active alumina to an
alumina sol during rehydration. Moreover, if the swellable clay is
merely mixed with preformed boehmite rather than forming the
boehmite. e.g., by rehydration of active alumina, in the presence
of the clay, the improved pore properties will not be obtained.
[0098] In a preferred embodiment, the aluminum oxide component can
be premilled prior to rehydration of the active alumina therein
alone or in admixture with the swellable clay. Premilling can be
conducted in wet mills such as DRAIS, PREMIER, or other types of
sand or pebble mills.
[0099] However, if the premilling is conducted in the absence of
the desired swellable clay, it must be conducted under conditions,
e.g., at sufficiently low temperatures, to avoid premature
rehydration of the alumina before contact thereof with the
dispersed swellable clay.
[0100] Premilling of the aluminum oxide component is conducted
typically at room temperature for a period sufficient to reduce the
average particle size to be typically from about 0.1 to about 8
(e.g., 1 to 8), preferably from about 0.1 to about 5 (e.g., 1 to
5), and most preferably from about 0.1 to about 2.5 microns.
[0101] The swellable clay component is dispersed in a slurry,
typically an aqueous slurry, under conditions which preferably will
maximize the degree of dispersion. Some swellable clays are more
readily dispersible than others. If the degree of dispersion
attained during contact with the alumina being rehydrated is poor,
the desired impact on the pore properties of the alumina may not be
attained or maximized. Accordingly. steps may need to be taken to
induce the proper degree of dispersion such as milling, total
volatiles control, and/or the use of dispersing aids such as
tetrasodium pyrophosphate (Na.sub.4P.sub.2O.sub.7). Slow addition
of the clay to deionized water or water containing
Na.sub.4P.sub.2O.sub.7 to minimize the amount of divalent cations
such as Ca.sup.+2 and Mg.sup.+2 helps to disperse the clay. The
time required to disperse the clay is reduced if it is added to a
high shear mixer such as COWLES, MYERS or SILVERSON mixer.
Satisfactory dispersion can be obtained with paddle type agitators,
particularly when a tank with baffles is used.
[0102] Attainment of the proper degree of dispersion is difficult
to quantify, but as a general rule, the greater the degree of
clarity of the suspending medium, the better the dispersion and a
completely clear medium is most preferred when employing a
synthetic hectorite. This will typically occur when the clay
particles are predominately colloidal in size, e.g., less than
about 1 micron.
[0103] Accordingly, dispersion of the swellable clay can be
accomplished by mixing the clay with water, preferably under
conditions of high shear for periods of typically from about 5 to
about 60, and preferably from about 10 to about 30 minutes. The
temperature at which the dispersion is formed is not critical and
will typically range from about 10 to about 60.degree. C. It is
important that the water not contain other minerals, e.g.,
deionized water is preferred, which would affect the dispersability
of the clay.
[0104] The degree of dispersion is enhanced if the starting clay
has a total volatile content of typically at least 6, and
preferably at least 8 wt. % thereof, and can range typically from
about 6 to about 30, preferably from about 10 to about 20 and most
preferably from about 12 to about 18 wt. %.
[0105] The amount of clay sought to be imparted to the final
composite particles is selected to be effective to increase at
least one of the total nitrogen pore volume, hydrothermal
stability, and/or the nitrogen mesopore pore mode relative to the
corresponding pore volume, hydrothermal stability (as defined
hereinafter) and mesopore pore mode of the aluminum oxide component
in the absence of the swellable clay. More specifically, the
mesopore pore mode is increased typically at least 10, preferably
at least 30, and most preferably at least 50% of the corresponding
mesopore pore mode achieved in the absence of the swellable
clay.
[0106] Suitable effective amounts of the swellable clay will
typically be less than about 10 (e.g., less than about 9),
preferably less than about 8, most preferably less than about 6 wt.
%, and can vary typically from about 1 to about 9 (e.g., 1 to about
8). preferably from about 2 to about 7, and most preferably from
about 2 to about 5 wt. % based on the combined weight of aluminum
oxide component and swellable clay component.
[0107] As the clay content of the composite particles increases
above 1 wt. %, not only is the mesopore pore volume increased, up
until about 6 wt. % swellable clay, after which it begins to
decrease, but also the surface area. In addition, the presence of
the clay increases the hydrothermal stability of the composite
particles up to about 10 w % clay content, after which it levels
off or decreases.
[0108] From the above discussion, it will be apparent that
rehydration of the alumina in the presence of the dispersed
swellable clay can be brought about in a variety of ways.
[0109] For example, two separately prepared slurries (dispersions)
containing the swellable clay component and non-colloidal aluminum
oxide component, respectively, can be combined or, preferably a
single slurry can be made directly by adding either component first
to water or simultaneously combining the clay and aluminum oxide
components with water.
[0110] However, if two separate slurries are prepared care should
be taken to assure that rehydration of the active alumina in the
aluminum oxide component does not occur prematurely before contact
with the dispersed clay.
[0111] The solids content of the slurry containing the aluminum
oxide component and clay component is controlled such that it is
typically from about 2 to about 30, preferably from about 4 to
about 25 and most preferably from about 5 to about 25 wt. % based
on the slurry weight. As the solids content decreases within these
ranges, the mesopore pore mode will typically increase and
vice-versa when the clay wt. % is at or below 4.
[0112] Accordingly, absent premilling of the clay component and
aluminum oxide component, it is preferred to prepare a slurry of
the dispersible clay component in dispersed form, add the aluminum
oxide component thereto and then subject the mixture to shear under
elevated temperature as described above to intimately disperse the
swellable oxide and rehydrate the alumina.
[0113] In one preferred embodiment, the dispersed clay component is
premilled in admixture with the aluminum oxide component prior to
rehydration of the alumina. Thus, in this embodiment, a slurry of
the swellable clay component is prepared under agitation until
fully dispersed. To the clay dispersion is added the appropriate
amount of aluminum oxide component, and the resultant combination
wet milled, preferably severely milled, at room temperature, e.g.,
in a DRAIS mill, for a period of typically from about 0.1 to about
3, preferably from about 0.5 to about 2.0 minutes. The premilled
slurry is then refluxed as described above to rehydrate the
alumina.
[0114] Premilling has been found to lead to increased hydrothermal
stability of the composition while resulting in only a slight shift
to smaller pores.
[0115] More specifically, the hydrothermal stability of the alumina
composite particles is evaluated by comparing fresh and steamed
surface areas as follows.
[0116] The BET N.sub.2 surface area is determined after calcining
in air at 537.8.degree. C. (1000.degree. F.) for 2 hours and
designated as the fresh surface area. An uncalcined sample is then
exposed to an atmosphere containing about 20 v % steam for 4 hours
at 800.degree. C. at autogenous pressure and BET surface area
determined thereon and designated the steamed surface area.
[0117] A comparison is then made between the fresh and steamed
surface areas. The smaller the difference between the fresh and
steamed surface areas, the higher the hydrothermal stability.
[0118] Once rehydration of the active alumina (in the aluminum
oxide component) in the presence of the swellable clay component is
complete, the resulting composite particles can be recovered,
thermally activated under the same conditions as described for
agglomerates hereinafter or used directly to conduct application of
catalyst thereto.
[0119] Preferably, the composite particles are recovered and dried
and optionally sized. Suitable particle sizes can range typically
from about 1 to about 150 (e.g., 1 to about 100), preferably from
about 2 to about 60, and most preferably from about 2 to about 50
microns.
[0120] Recovery is accomplished by filtration, evaporation,
centrifugation and the like. The slurry may also be spray dried to
effect recovery.
[0121] The resulting composite particles have a nitrogen BET
surface area (on a metals free basis) of typically at least about
200, preferably at least about 240, and most preferably at least
about 260 m.sup.2/g, which surface area can range typically from
about 200 to about 400, preferably from about 240 to about 350, and
most preferably from about 240 to about 300 m.sup.2/g. The surface
area determination is made on a sample which has been dried at
138.degree. C. (280.degree. F.) for 8 hours and calcined for 2
hours at 537.8.degree. C. (1000.degree. F.).
[0122] The average nitrogen pore diameter of the composite
particles will range typically from about 60 to about 400 (e.g., 60
to about 300), preferably from about 70 to about 275, and most
preferably from about 80 to about 250 Angstroms.
[0123] The total nitrogen pore volume of the composite particles
(on a metals free basis) can vary from about 0.5 to about 2.0.
preferably from about 0.6 to about 1.8, and most preferably from
about 0.7 to about 1.6 cc/g. Prior to testing for pore diameter or
pore volume, the samples are oven dried at 138.degree. C.
(280.degree. F.) and then calcined for 2 hours at 537.8.degree. C.
(1000.degree. F.).
[0124] It is an advantage of the present invention that the
swellable clay shifts the mesopore pore mode to a higher pore
diameter relative to its absence while still maintaining a high
surface area as recited above.
[0125] Even more importantly, the present invention provides a
mechanism for controlling the size of the pore mode by varying the
preparation conditions, particularly the clay content in the
composite and the solids content of the rehydration slurry. More
specifically, reductions in clay content from the optimum and/or
increases in the rehydration slurry solids content will each lower
the pore mode.
[0126] Thus, the macropore content (i.e., % of those pores within
the total nitrogen pore volume which fall within the macropore
region) of the composite particles will be typically not greater
than about 40, preferably not greater than about 30, and most
preferably not greater than about 25% of the total pore volume,
which macropore content will range typically from about 5 to about
50. preferably from about 10 to about 40, and most preferably from
about 10 to about 30% of the total pore volume.
[0127] The nitrogen mesopore content will range typically from
about 20 to about 90, preferably from about 30 to about 80, and
most preferably from about 40 to about 70% of the total pore
volume. Moreover, typically at least about 40, preferably at least
about 50, and most preferably at least about 60% of the pores
within the mesopore region will have pore diameters of typically
from about 100 to about 400, preferably from about 100 to about
350, and most preferably from about 125 to about 300 Angstroms.
[0128] The nitrogen mesopore content of the composite particles as
formed also desirably will possess a nitrogen pore mode, preferably
only a single pore mode (monomodal), of typically from about 60 to
about 400 (e.g. 60 to about 300), preferably from about 70 to about
275, and most preferably from about 80 to about 250 Angstroms.
[0129] The nitrogen micropore content of the composite particles
will be typically not greater than about 80, preferably not greater
than about 60, and most preferably not greater than about 50% of
the total pore volume which micropore content can range typically
from about 80 to about 5, preferably from 60 about to about 10, and
most preferably from about 30 to about 15% of the total pore
volume.
[0130] It has been further found that the hydrothermal stability of
the composite particles can be further improved by the
incorporation of silicate salts therein.
[0131] Suitable silicate salts include the alkali and alkaline
earth metal silicates, most preferably sodium silicate. Less
soluble silicates, such as found in natural or synthetic clays or
silica gels also improve stability. Examples of such clays are
kaolinite. montmorillonite, and hectorite. Calcined clays also give
improved hydrothermal stability.
[0132] The silicate can be added to the aluminum oxide and
swellable clay components prior to rehydration, but it is preferred
to conduct the addition after rehydration (hot aging) to maximize
the hydrothermal stability inducing effects. and to obtain a high
pore volume and high average pore diameter. Addition of soluble
silicate before rehydration of the alumina tends to produce small
pores which are somewhat less stable (i.e., coalesce into larger
pores upon heating) than large ones thereby reducing the total pore
volume. The silicate can be added after a few hours of hot aging
after the pore size distribution is set.
[0133] Amounts of silicate effective to improve the hydrothermal
stability of the composite particles described herein can range
typically from about 0.1 to about 40, preferably from about 1 to
about 20, and most preferably from about 2 to about 10 wt. %, based
on the combined weight of silicate, aluminum oxide component and
swellable clay component.
[0134] Without wishing to be bound by any particular theory, it is
believed that the added silicate is distinguishable from the
silicate in the clay in that the former is believed to be free to
migrate to the alumina during rehydration whereas the clay silicate
remains mostly intact during rehydration. However, some of the
observed effect of the clay on the pore size and stability may be
attributable to silicate migrated from the clay to the alumina
during rehydration.
[0135] While the composite alumina particles can be used directly
as supports, it is more conventional to agglomerate the particles
for such use.
[0136] Such alumina agglomerates can be used as catalysts or
catalyst supports in any reaction which requires a particular pore
structure together with very good mechanical, thermal and
hydrothermal properties. The agglomerates of the present invention
can thus find particular applicability as catalyst supports in the
treatment of exhaust gases generated by internal combustion engines
and in hydrogen treatments of petroleum products, such as
hydrodesulfurization, hydrodemetallation and hydrodenitrification.
They can also be used as catalyst supports in reactions for the
recovery of sulfur compounds (Claus catalysis), the dehydration,
reforming, steam reforming, dehydrohalogenation, hydrocracking,
hydrogenation, dehydrogenation, and dehydrocyclization of
hydrocarbons or other organic compounds, as well as oxidation and
reduction reactions. They can also be used as additives for fluid
cracking catalysts, particularly to enhance pore volume and meso or
macroporosity.
[0137] They may also be used as catalysts per se in reactions
typically catalyzed by aluminas such as hydrocracking and
isomerization reactions.
[0138] Thus, the advantageous properties of enhanced mesopore
content at higher surface area and hydrothermal stability of the
composite particles are passed on to the agglomerates.
[0139] The term "agglomerate" refers to a product that combines
particles which are held together by a variety of physical-chemical
forces.
[0140] More specifically, each agglomerate is composed of a
plurality of contiguous. constituent primary particles, sized as
described above, preferably joined and connected at their points of
contact.
[0141] Thus, the agglomerates of the present invention may exhibit
a higher macropore content than the constituent primary particles
because of the interparticle voids between the constituent
composite alumina particles.
[0142] Nevertheless, the agglomerate particles still preserve the
higher mesopore mode.
[0143] Accordingly, the agglomerates of the present invention are
characterized as having the following properties (on a metals free
basis) after drying for 8 hours at 121.degree. C. (250.degree. F.)
and calcination for 1 hour at 537.8.degree. C. (1000.degree.
F.):
[0144] (1) a nitrogen surface area of at least about 100,
preferably at least about 150, and most preferably from at least
about 200 m.sup.2/g. which surface area can range typically about
100 to about 400, preferably from about 125 to about 375. and most
preferably from about 150 to about 350 m.sup.2/g.
[0145] (2) a bulk density of the agglomerates of typically at least
about 0.30, preferably at least about 0.35. and most preferably at
least about 0.40 g/ml which bulk density can range typically from
about 0.30 to about 1, preferably from about 0.35 to about 0.95.
and most preferably from about 0.40 to about 0.90 g/ml.
[0146] (3) a total mercury pore volume of from about 0.40 to about
2.0. preferably from about 0.5 to about 1.8. and most preferably
from about 0.6 to about 1.5 cc/g,
[0147] (4) a macropore content (i.e.. those pores within the total
pore volume which fall within the macropore region) of typically
not greater than about 40, preferably not greater than about 30,
and most preferably not greater than about 20%, of the total pore
volume, which macropore content will range typically from about 5
to about 40, preferably from about 10 to about 35, and most
preferably from about 15 to about 30% of the total pore volume,
[0148] (5) a mesopore content of typically from about 15 to about
95, preferably from about 20 to about 90, and most preferably from
about 30 to about 80% of the total pore volume. Moreover, typically
at least about 30, preferably at least about 40, and most
preferably at least about 50% of the pores within the mesopore
region will have pore diameters of typically from about 80 to about
400 (e.g., 100 to 400), preferably from about 90 to about 350
(e.g.. 100 to 350), and most preferably from about 105 to about 300
Angstroms,
[0149] (6) an average agglomerate particle diameter of typically
from about 0.5 to about 5, preferably from about 0.6 to about 2.
and most preferably from about 0.8 to 1.5 mm.
[0150] The mesopore content of the agglomerate particles as
calcined also desirably will possess a mesopore pore mode of
typically from about 60 to about 400 (e.g., 60 to about 300),
preferably from about 65 to about 275, and most preferably from
about 70 to about 250 Angstroms.
[0151] In addition, the agglomerates may be mixed with other
conventional aluminas to produce supports having a pore size
distribution with two or more modes in the mesopore region. Each
alumina contributes a mesopore mode at its unique characteristic
position. Mixtures of two or more aluminas prepared with the
swellable clays having varying pore modes are also
contemplated.
[0152] The agglomeration of the alumina composite is carried out in
accordance with the methods well known to the art, and, in
particular, by such methods as pelletizing, extrusion, shaping into
beads in a rotating coating drum, and the like. The nodulizing
technique whereby composite particles having a diameter of not
greater than about 0.1 mm are agglomerated to particles with a
diameter of at least about 1 mm by means of a granulation liquid
may also be employed.
[0153] As is known to those skilled in the art, the agglomeration
may optionally be carried out in the presence of additional
amorphous or crystalline binders, and pore-forming agents may be
added to the mixture to be agglomerated. Conventional binders
include other forms of alumina, silica, silica-alumina, clays,
zirconia, silica-zirconia, magnesia and silica-boria. Conventional
pore-forming agents which can be used in particular, include wood
flour, wood charcoal, cellulose, starches, naphthalene and, in
general, all organic compounds capable of being removed by
calcination. The addition of pore forming agents, however, is not
necessary or desirable.
[0154] If necessary, the aging, drying and/or calcination of the
agglomerates are then carried out.
[0155] The agglomerates, once formed, are then typically subjected
to a thermal activation treatment at a temperature in the range of
typically from about 250 to about 1000, preferably from about 350
to about 900, and most preferably from about 400 to about
800.degree. C. for periods of typically from about 0.15 to about
3.0, preferably from about 0.33 to about 2.0, and most preferably
from about 0.5 to about 1 hour(s). The atmosphere of activation is
typically air, but can include inert gases such as nitrogen or
steam.
[0156] The activation treatment can be carried out in several steps
if desired or be part of the agglomerate treatment. Depending on
the particular activation temperature and time employed, the
alumina agglomerates predominantly exhibit the crystal structure
characteristic of boehmite, or gamma alumina, or mixtures
thereof.
[0157] More specifically, at calcination temperatures and times
increasingly above about 300.degree. C. and one hour, the boehmite
will be increasingly converted to gamma alumina. However, the gamma
alumina will possess the pore properties of the boehmite from which
it is derived. Moreover, at the preferred calcination temperatures
and times substantially all of the crystalline boehmite is
converted to gamma alumina. Consequently, the sum of the
crystalline boehmite content (wt. %) discussed above plus the gamma
alumina content resulting from calcination of the boehmite, will
not typically exceed the original boehmite content derived from
rehydration of the active alumina. This conclusion applies equally
to composite particles which are activated and used directly in
composite particle form without agglomeration.
[0158] The percent .gamma.-Al.sub.2O.sub.3 (gamma alumina) is
determined as follows:
[0159] (1) 100% .gamma.-Al.sub.2O.sub.3 is defined as an integrated
intensity (area under the peak) of the (440) peak of a
.gamma.-Al.sub.2O.sub.3 standard.
[0160] (2) The (101) peak intensity of a Quartz plate is used as an
X-ray intensity monitor.
[0161] (3) Data collection is performed on a Philips.RTM. 3720
automatic diffractometer equipped with a graphite diffract beam
monochromator and sealed Cu X-Ray tube. The X-ray generator is
operated at 45 kV and 40 mA.
[0162] (4) Full width at half maximum (FWHM) and integrated
intensity (area under the peak) of the (440)
.gamma.-Al.sub.2O.sub.3 peak are obtained by curve fitting. In the
case where one peak can not yield a good fit of the peak, two peaks
are used. In the case where two peaks are used for curve fitting,
two crystallite sizes are obtained by using Equation 3. Percent
.gamma.-Al.sub.2O.sub.3 of the two crystallite sizes are obtained
by using Equation 2.
[0163] (5) The percentage of .gamma.-Al.sub.2O.sub.3 of a sample is
determined by the following equation:
% .sub..gamma.-Al2O3=(I.sub.sample*I.sub.quartz
c)/(I.sub.standard*I.sub.q- uartz.s) (Equation 2)
[0164] wherein:
[0165] I.sub.sample=Integrated intensity of the (440) peak of
sample;
[0166] I.sub.quartz c=Intensity of the (101) quartz peak, measured
at the time that the standard .gamma.-Al.sub.2O.sub.3 is
measured;
[0167] I.sub.standard=Integrated intensity of the (440) peak of the
standard .gamma.-Al.sub.2O.sub.3; and
[0168] I.sub.quartz.s=Intensity of the (101) quartz peak, measured
at the time the sample is measured.
[0169] .gamma.-Al.sub.2O.sub.3 crystallite size (L) is determined
by the following procedure. The sample is hand ground with a mortar
and pestle. An even layer of the sample is placed on 3.5 gms
polyvinyl alcohol (PVA) and pressed for 10 seconds at 3,000 psi to
obtain a pellet. The pellet is then scanned with Cu K Alpha
radiation and the diffraction pattern between 63 and 73 degrees
(2.theta.) is plotted. The peak at 66.8 degrees (2.theta.) is used
to calculate the crystallite size using Equation 3 and the measured
peak width at half height.
L(size in .ANG.)=82.98/FWHM(2.theta..degree.) cos (.theta..degree.)
(Equation 3)
[0170] wherein:
[0171] FWHM=Full width at half maximum; and
[0172] .theta.=The angle of diffraction between X-ray beam and
planar surface on which the sample is sitting.
[0173] The percent boehmite is determined as described at Example
1.
[0174] The large average pore diameter and high pore volume render
the alumina composites of the present invention useful for the
treatment of: high molecular weight, high boiling feeds, where not
all the feed can be practically vaporized, in both F.C.C. and
hydroprocessing operations; short contact time cracking operations,
where the large pores can minimize diffusion resistance:
hydrocracking, hydrotreating. hydro-desulfurization and hydro
denitrogenation; processing of tar sands. shale oil extracts or
coal liquids; catalyst supports with metals, the high pore volume
and pore diameter providing for improved metal dispersion;
separation of high molecular weight compounds in a solvent from
lower molecular weight compounds; and applications requiring fine
particle size aluminas at low pH, such as in suspending agents, and
polishing agents.
[0175] The alumina composite particles are particularly adapted for
use as supports for a variety of catalyst systems employing heavy
metals as the catalyst component. Consequently, the metal
components of such catalysts must be added and incorporated into
the alumina composite. Thermal activation is typically conducted
after agglomerate formation rather than before.
[0176] Such additions can be achieved by mixing the catalytic
materials with the alumina during the production of the composite
alumina but after rehydration thereof, during the preparation of
the agglomerates. e.g.. extrudates or pellets and the like, by
impregnating the alumina agglomerates, such as extrudates or
pellets, with catalytic material by immersion in solutions
containing the catalytic material and the like. The "dry"
impregnation technique is another suitable alternative wherein the
composite particles or agglomerates are contacted with a quantity
of impregnation liquid, the volume of which corresponds to the pore
volume of the support. Other and additional methods of modifying
the alumina may appear desirable to those skilled in the art.
[0177] The porous composite aluminas of the present invention are
particularly useful when employed as supports for catalytically
active hydrogenation components such as Group VIB and Group VIII
metals. These catalytically active materials can be suitably
applied in hydroprocessing operations.
[0178] More specifically, "hydroprocessing" as the term is employed
herein means oil refinery processes for reacting petroleum
feedstocks (complex mixtures of hydrocarbon present in petroleum
which are liquid at conditions of standard temperature and
pressure) with hydrogen under pressure in the presence of a
catalyst to lower: (a) the concentration of at least one of sulfur,
contaminant metals, nitrogen, and Conradson carbon, present in said
feedstock, and (b) at least one of the viscosity, pourpoint, and
density of the feedstock. Hydroprocessing includes hydrocracking,
isomerization/dewaxing, hydrofinishing, and hydrotreating processes
which differ by the amount of hydrogen reacted and the nature of
the petroleum feedstock treated.
[0179] Hydrofinishing is typically understood to involve the
hydroprocessing of hydrocarbonaceous oil containing predominantly
(by weight of) hydrocarbonaceous compounds in the lubricating oil
boiling range ("feedstock") wherein the feedstock is contacted with
solid supported catalyst at conditions of elevated pressure and
temperature for the purpose of saturating aromatic and olefinic
compounds and removing nitrogen, sulfur, and oxygen compounds
present within the feedstock, and to improve the color, odor,
thermal, oxidation, and UV stability, properties of the
feedstock.
[0180] Hydrocracking is typically understood to involve the
hydroprocessing of predominantly hydrocarbonaceous compounds
containing at least five (5) carbon atoms per molecule
("feedstock") which is conducted: (a) at superatmospheric hydrogen
partial pressure; (b) at temperatures typically below 593.3.degree.
C. (1100.degree. F.); (c) with an overall net chemical consumption
of hydrogen; (d) in the presence of a solid supported catalyst
containing at least one (1) hydrogenation component; and (e)
wherein said feedstock typically produces a yield greater than
about one hundred and thirty (130) moles of hydrocarbons containing
at least about three (3) carbon atoms per molecule for each one
hundred (100) moles of feedstock containing at least five (5)
carbon atoms per molecule.
[0181] Hydrotreating is typically understood to involve the
hydroprocessing of predominantly hydrocarbonaceous compounds
containing at least five carbon atoms per molecule ("feedstock")
for the desulfurization and/or denitrification of said feedstock,
wherein the process is conducted: (a) at superatmospheric hydrogen
partial pressure; (b) at temperatures typically below 593.3.degree.
C. (1100.degree. F.); (c) with an overall net chemical consumption
of hydrogen; (d) in the presence of a solid supported catalyst
containing at least one hydrogenation component; and (e) wherein:
(i)the feedstock produces a yield of typically from about 100 to
about 130 moles (inclusive) of hydrocarbons containing at least
three carbon atoms per molecule for each 100 moles of the initial
feedstock; or (ii) the feedstock comprises at least 50 liquid
volume percent of undeasphalted residue typically boiling above
about 565.6.degree. (1050.degree. F.) as determined by ASTM D-1160
Distillation and where the primary function of the hydroprocessing
is to desulfurize said feedstock: or (iii) the feedstock is the
product of a synthetic oil producing operation.
[0182] Isomerization/dewaxing is typically understood to involve
hydroprocessing predominantly hydrocarbonaceous oil having a
Viscosity Index (VI) and boiling range suitable for lubricating oil
("feedstock") wherein said feedstock is contacted with solid
catalyst that contains, as an active component, microporous
crystalline molecular sieve, at conditions of elevated pressure and
temperature and in the presence of hydrogen, to make a product
whose cold flow properties are substantially improved relative to
said feedstock and whose boiling range is substantially within the
boiling range of the feedstock.
[0183] More specifically, well known hydroprocessing catalyst
components typically include at least one component of a metal
selected from the group consisting of Group VIII metals, including
Group VIII platinum group metals, in particular platinum and
palladium, the Group VIII iron group metals, in particular cobalt
and nickel, the Group VI B metals, in particular molybdenum and
tungsten, and mixtures thereof. If the feedstock has a sufficiently
low sulfur content, e.g., less than about 1 weight percent and
preferably less than about 0.5 weight percent, the Group VIII
platinum group metals may be employed as the hydrogenation
component. In this embodiment. the Group VIII platinum group metal
is preferably present in an amount in the range of about 0.01
weight percent to about 5 weight percent of the total catalyst,
based on elemental platinum group metal. When the feedstock being
treated contains more than about 1.0 weight percent sulfur, the
hydrogenation component is preferably a combination of at least one
Group VIII iron group metal and at least one Group VI B metal. The
non-noble metal hydrogenation components are preferably present in
the final catalyst composition as oxides or sulfides, more
preferably as sulfides. Preferred overall catalyst compositions
contain at least about 2, preferably about 5 to about 40, wt. %
Group VIB metal, more preferably molybdenum and/or tungsten, and
typically at least about 0.5, and preferably about 1 to about 15,
wt. % of Group VIII of the Periodic Table of Elements, more
preferably nickel and/or cobalt, determined as the corresponding
oxides. The sulfide form of these metals is more preferred due to
higher activity, selectivity and activity retention.
[0184] The catalyst components, e.g., hydroprocessing catalyst
components, can be incorporated into the overall catalyst
composition by any one of numerous procedures as described.
[0185] Although the non-noble metal components can be combined into
the catalyst as the sulfides, this is not preferred. Such
components are usually combined as a metal salt which can be
thermally converted to the corresponding oxide in an oxidizing
atmosphere or reduced with hydrogen or other reducing agent. The
composition can then be sulfided by reaction with a sulfur compound
such as carbon disulfide, hydrogen sulfide, hydrocarbon thiols,
elemental sulfur, and the like.
[0186] Catalyst components can be incorporated into the composite
alumina at any one of a number of stages in the catalyst
preparation. For example, metal compounds, such as the sulfides,
oxides or water-soluble salts such as ammonium heptamolybdate,
ammonium tungstate, nickel nitrate, cobalt sulfate and the like,
can be added by co-mulling, impregnation or precipitation, after
rehydration but before the composite is finally agglomerated. In
the alternative, these components can be added to the composite
after agglomeration by impregnation with an aqueous, alcoholic or
hydrocarbon solution of soluble compounds or precursors.
[0187] A further embodiment of the present invention is directed to
a process for the hydrotreating of a hydrocarbon feedstock in at
least one ebullated bed reaction zone. More particularly, the
hydrocarbon feedstock is contacted with hydrogen in one or a series
of ebullated bed reaction zones in the presence of a
hydroprocessing catalyst comprising a hydrogenation component of
catalytic metals and derivatives as described above deposited on
agglomerates of the alumina composite described herein.
[0188] As is well known these feedstocks contain nickel, vanadium,
and asphaltenes, e.g., about 40 ppm up to more than 1,000 ppm for
the combined total amount of nickel and vanadium and up to about 25
wt. % asphaltenes. Further, the economics of these processes
desirably produce lighter products as well as a demetallized
residual by-product. This process is particularly useful in
treating feedstocks with a substantial amount of metals containing
150 ppm or more of nickel and vanadium and having a sulfur content
in the range of about 1 wt. % to about 10 wt. %. Typical feedstocks
that can be treated satisfactorily by the process of the present
invention contain a substantial amount (e.g., about 90%) of
components that boil appreciably above 537.8.degree. C.
(1,000.degree. F.). Examples of typical feedstocks are crude oils,
topped crude oils, petroleum hydrocarbon residua, both atmospheric
and vacuum residua, oils obtained from tar sands and residua
derived from tar sand oil, and hydrocarbon streams derived from
coal. Such hydrocarbon streams contain organometallic contaminants
which create deleterious effects in various refining processes that
employ catalysts in the conversion of the particular hydrocarbon
stream being treated. The metallic contaminants that are found in
such feedstocks include, but are not limited to, iron, vanadium,
and nickel.
[0189] While metallic contaminants, such as vanadium, nickel, and
iron, are often present in various hydrocarbon streams, other
metals are also present in a particular hydrocarbon stream. Such
metals exist as the oxides or sulfides of the particular metal, or
as a soluble salt of the particular metal, or as high molecular
weight organometallic compounds, including metal naphthenates and
metal porphyrins, and derivatives thereof.
[0190] Another characteristic phenomenon of hydrotreating heavy
hydrocarbons is the precipitation of insoluble carbonaceous
substances from the asphaltenic fraction of the feedstock which
cause operability problems. The amount of such insolubles formed
increases with the amount of material boiling over 537.8.degree. C.
(1,000.degree. F.) which is converted or with an increase in the
reaction temperature employed. These insoluble substances, also
known as Shell hot filtration solids, create the operability
difficulties for the hydroconversion unit and thereby circumscribe
the temperatures and feeds the unit can handle. In other words, the
amount of solids formed limit the conversion of a given feedstock.
Operability difficulties as described above may begin to manifest
themselves at solids levels as low as 0.1 wt. %. Levels below 0.5
wt. % are generally recommended to prevent fouling of process
equipment. A description of the Shell hot filtration test is found
at A. J. J., Journal of the Inst. of Petroleum (1951) 37, pp.
596-604 by Van Kerkvoort. W. J. and Nieuwstad. A. J. J. which is
incorporated herein by reference.
[0191] It has been speculated that such insoluble carbonaceous
substances are formed when the heavy hydrocarbons are converted in
the hydroconversion unit, thereby rendering them a poorer solvent
for the unconverted asphaltenic fraction and hence creating the
insoluble carbonaceous substances. The formation of such insolubles
can be decreased by having some of the surface area in the
hydroconversion catalyst be accessible by very large pores so that
most of the catalyst surface is accessible to large asphaltenic
molecules. Also, the large pores facilitate deposition of nickel
and vanadium in the hydrotreating catalyst without plugging the
pores.
[0192] It has been discovered that the use of the porous composites
as supports in making catalysts, particularly hydroprocessing
catalysts, provides a higher initial activity than the catalysts
supported on conventional alumina.
[0193] While the benefit of higher initial activity is less
significant in a fixed bed operation, it is particularly important
in an ebullated bed system. More specifically, in an ebullated bed
system, increases in initial activity are meaningful since there is
an intermittent or continuous addition of catalyst to increase and
maintain overall system activity. Since the overall activity of an
ebullated bed system is the weighted average activity of all
catalyst present varying from fresh to deactivated, the overall
activity is increased by constant or intermittent addition of
catalyst possessing a relatively higher initial activity.
[0194] Hydrotreating operations are typically carried out in one or
a series of ebullated bed reactors. As previously elucidated, an
ebullated bed is one in which the solid catalyst particles are kept
in random motion by the upward flow of liquid and gas. An ebullated
bed typically has a gross volume of at least 10 percent greater and
up to 70% greater than the solids thereof in a settled state. The
required ebullition of the catalyst particles is maintained by
introducing the liquid feed, inclusive of recycle if any, to the
reaction zone at linear velocities ranging from about 0.02 to about
0.4 feet per second and preferably, from about 0.05 to about 0.20
feet per second.
[0195] The operating conditions for the hydrotreating of heavy
hydrocarbon streams, such as petroleum hydrocarbon residua and the
like, are well known in the art and comprise a pressure within the
range of about 1.000 psia (68 atmos) to about 3,000 psia (204
atmos), an average catalyst bed temperature within the range of
about 700.degree. F. (371.degree. C.) to about 850.degree. F.
(454.degree. C.), a liquid hourly space velocity (LHSV) within the
range of about 0.1 volume of hydrocarbon per hour per volume of
catalyst to about volumes of hydrocarbon per hour per volume of
catalyst, and a hydrogen recycle rate or hydrogen addition rate
within the range of about 2,000 standard cubic feet per barrel
(SCFB) (356 m.sup.3/m.sup.3) to about 15.000 SCFB (2.671
m.sup.3/m.sup.3). Preferably. the operating conditions comprise a
total pressure within the range of about 1,200 psia to about 2,000
psia (81-136 atmos); an average catalyst bed temperature within the
range of about 730.degree. F. (387.degree. C.) to about 820.degree.
F. (437.degree. C.): and a LHSV within the range of about 0.1 to
about 4.0; and a hydrogen recycle rate or hydrogen addition rate
within the range of about 5,000 SCFB (890 m.sup.3/m.sup.3) to about
10,000 SCFB (1.781 m.sup.3/m.sup.3). Generally, the process
temperatures and space velocities are selected so that at least 30
vol. % of the feed fraction boiling above 1,000.degree. F. is
converted to a product boiling below 1,000.degree. F. and more
preferably so that at least 70 vol. % of the sublect fraction is
converted to a product boiling below 1,000.degree. F.
[0196] For the treatment of hydrocarbon distillates, the operating
conditions would typically comprise a hydrogen partial pressure
within the range of about 200 psia ( 13 atmos) to about 3,000 psia
(204 atmos): an average catalyst bed temperature within the range
of about 600.degree. F. (315.degree. C.) to about 800.degree. F.
(426.degree. C.); a LHSV within the range of about 0.4 volume of
hydrocarbon per hour per volume of catalyst to about 6 volumes of
hydrocarbon recycle rate or hydrogen addition rate within the range
of about 1,000 SCFB (178 m.sup.3/m.sup.3) to about 10.000 SCFB
(1,381 m.sup.3/m.sup.3). Preferred operating conditions for the
hydrotreating of hydrocarbon distillates comprise a hydrogen
partial pressure within the range of about 200 psia (13 atmos) to
about 1,200 psia (81 atmos); an average catalyst bed temperature
within the range of about 600.degree. F. (315.degree. C.) to about
750.degree. F. (398.degree. C.); a LHSV within the range of about
0.5 volume of hydrocarbon per hour per volume of catalyst to about
4 volumes of hydrocarbon per hour per volume of catalyst; and a
hydrogen recycle rate or hydrogen addition rate within the range of
about 1,000 SCFB (178 m.sup.3/m.sup.3) to about 6,000 SCFB (1,068
m.sup.3/m.sup.3).
[0197] The most desirable conditions for conversion of a specific
feed to a predetermined product, however, can be best obtained by
converting the feed at several different temperatures, pressures,
space velocities and hydrogen addition rates, correlating the
effect of each of these variables and selecting the best compromise
of overall conversion and selectivity.
[0198] All references herein to elements or metals belong to a
certain Group refer to the Periodic Table of the Elements and
Hawley's Condensed Chemical Dictionary. 12.sup.th Edition. Also,
any references to the Group or Groups shall be to the Group or
Groups as reflected in this Periodic Table of Elements using the
CAS system for numbering groups.
[0199] All references in the claims to morphological properties
defined in terms of a weight, such as surface area, and pore volume
are to be interpreted as being on a metals free basis as defined in
Equation 6, e.g., normalized to correct for any influence of the
metal catalytic oxide (if present) on the weight of the material
being analyzed. Unless otherwise specified, all composites in
powder form (non-agglomerated) in the examples are filtered after
rehydration and then exchanged to low soda by A/S exchange as
described hereinabove prior to calcination. None of the extruded
samples were A/S exchanged.
[0200] The following examples are given as specific illustrations
of the claimed invention. It should be understood, however, that
the invention is not limited to the specific details set forth in
the examples. All parts and percentages in the examples, as well as
in the remainder of the specification, are by weight unless
otherwise specified. Unless otherwise specified herein, all surface
area and pore property determinations or recitations in the
specification and claims are to be construed as being made on
samples which have been oven dried at 138.degree. C. (280.degree.
F.) and then calcined at 537.8.degree. C. (1000.degree. F.) for 2
hours at atmospheric pressure in air.
[0201] Further, any range of numbers recited in the specification
or claims, such as that representing a particular set of
properties, conditions, physical states or percentages, is intended
to literally incorporate expressly herein any number falling within
such range, including any subset of numbers within any range so
recited.
EXAMPLE 1
[0202] To 1843 gm H.sub.2O was added 14.4 gm. dry basis, of
Laponite.RTM. RD, a synthetic hectorite clay available from LaPorte
Industries, Ltd. The resulting mixture was rapidly agitated for 20
minutes to disperse the clay. A very slightly cloudy solution
forms. almost water clear indicating very well dispersed finely
divided clay. To the Laponite.RTM. dispersion was added 23.5 gm of
a 10% sodium gluconate aqueous solution followed by 465.6 gm of a
calcined active alumina. CP-3 from ALCOA. The slurry was boiled
under reflux for 24 hours. The slurry was filtered and dried
overnight at 137.8.degree. C. (280.degree. F.). The resulting
composite particles were then dry calcined for 2 hours at
537.8.degree. C. (referred to herein as fresh), or calcined for 4
hours at 800.degree. C. in an atmosphere of 20V % steam (referred
to herein as steamed) and the surface area measured for the fresh
and steamed samples.
[0203] The percent conversion of the alumina sample to crystalline
boehmite was determined as follows:
[0204] (1) 100% boehmite is defined as an integrated intensity
(area under the peak) of the (020) peak of Catapal alumina.
[0205] (2) The (101) peak intensity of a Quartz plate is used as an
X-ray intensity monitor.
[0206] (3) Data collection is performed on a Philips.RTM. 3720
automatic diffractormeter equipped with a graphite diffract beam
monochromator and sealed Cu X-Ray tube. The X-ray generator is
operated at 45 kV and 40 mA
[0207] (4) Full width at half maximum (FWHM) and integrated
intensity (area under the peak) of the (020) boehmite peak are
obtained by curve fitting. In the case where one peak can not yield
a good fit of the peak. two peaks are used. In the case where two
peaks are used for curve fitting, two crystallite sizes are
obtained by using Equation 5. Percent boehmite of the two
crystallite sizes are obtained by using Equation 4.
[0208] (5) The percentage of boehmite of a sample is determined by
the following equation:
%.sub.boehmite=(I.sub.sample*I.sub.quartz
c)/(I.sub.catapal*I.sub.quartz.s- ) (Equation 4)
[0209] wherein
[0210] I.sub.sample=Integrated intensity of the (020) peak of
sample:
[0211] I.sub.quartz c=Intensity of the (101) quartz peak, measured
at the time Catapal alumina was measured;
[0212] I.sub.catapal=Integrated intensity of the (020) peak of the
Catapal alumina, and
[0213] I.sub.quartz.s=Intensity of the (101) quartz peak, measured
at the time sample was measured.
[0214] Boehmite crystallite size (L) is determined by the following
procedure. The sample is hand ground with a mortar and pestle. An
even layer of the sample is placed on 3.5 gms polyvinyl alcohol
(PVA) and pressed for 10 seconds at 3,000 psi to obtain a pellet.
The pellet is then scanned with Cu K Alpha radiation and the
diffraction pattern between 22 and 33 degrees (2.theta.) is
plotted. The peak at 28 degrees (2.theta.) is used to calculate the
crystallite size using Equation 5 and the measured peak width at
half height.
L(size in .ANG.)=82.98/FWHM(2.theta..degree.) cos (.theta..degree.)
(Equation 5)
[0215] wherein
[0216] FWHM=Full width at half maximum; and
[0217] .theta.=The angle of diffraction between X-ray beam and
planar surface on which the sample is sitting.
[0218] The resultant properties analyzed are reported at Table 2
and FIG. 1 and designated Run 2. The addition of 3% Laponite.RTM.
gave increased fresh and steamed surface areas compared to
Comparative Example 1. FIG. 1 also illustrates a large increase in
total nitrogen pore volume and shift to larger pores.
Comparative Example 1
[0219] Example 1 was repeated except that no Laponite.RTM. was
added to the sample. The results are reported at Table 2, FIG. 1
and designated Run 1.
3TABLE 2 EFFECT OF ADDITION OF 3% LAPONITE .RTM. ON THE SURFACE
PROPERTIES OF BOEHMITE OBTAINED BY REHYDRATION OF ACTIVE ALUMINA 1
2 RUN NO. Comp Ex. 1 Example 1 Wt. % Laponite .RTM. 0 3 Boehmite
Properties-After Hot Age 24 Hours At 100.degree. C. (212.degree.
F.) Average Pore Diameter (.ANG.) 149 197 Total Pore Volume (cc/g)
0.668 1.378 Pore Volume >600.ANG. (cc/g) 0.046 0.298 Mesopore
Pore Volume (cc/g) 0.205 0.774 Mesopore Content (% TPV) 30.6 56.2
Macropore SA (m.sup.2/g) 2.8 17.2 Mesopore Pore Mode (.ANG.) 70 200
% Increase In Mesopore Pore Mode N/A 185 SURFACE AREA 2 Hours @
537.8.degree. C. (Fresh) (m.sup.2/g) 179 279 Micropore Surface Area
(Fresh) (m.sup.2/g) 0 0 Mesopore Surface Area (Fresh) (m.sup.2/g)
179 279 % Conversion Of Active Alumina 83 78 To Boehmite SA - 4
Hours @ 800.degree. C., 112 182 20V % Steam (m.sup.2/g)
EXAMPLE 2
[0220] Example 1 was repeated except that the level of the
synthetic hectorte, Laponite.RTM. was varied from 0.1 to 10 wt. %
of the total solids (Laponite.RTM.+alumina) (corresponding to Runs
3-12). After a 24 hour age at reflux, the samples were filtered and
dried overnight at 137.8.degree. C. (280.degree. F.). The boehmite
crystallite size of selected samples was measured as well as the
surface area after two hours at 537.8.degree. C. (1000.degree. F.),
or 4 hours in 20V % steam at 800.degree. C. Also measured was the
dispersability index (DPI) of the composite particles. This test
measured the % of particles having a particle diameter of <1
micron after dispersing in water with a measured amount of HCl (237
milliequivalents/mole alumina) and mixing. The results of the level
of synthetic hectorite on the boehmite properties are summarized at
Table 3. It will be observed that the dispersible swelling
clay:
[0221] (a) increased total nitrogen pore volume and average pore
diameter to a maximum value in the 3-5 wt. % range;
[0222] (b) reduced Boehmite crystallite size:
[0223] (c) significantly increased fresh and steamed surface area
and nitrogen pore volume; and
[0224] (d) increased dispersability of the alumina when 3 wt. % or
more clay was added.
[0225] It was also noted that as the wt. % synthetic clay added was
increased, the hardness of the oven dried boehmite increased. At 0
wt. % the oven dried material was a soft powder, at 3 wt. % clay it
was moderately hard, while at 5-10 wt. % it was quite hard. This is
believed to indicate that extrudates/beads made from the composite
particles having levels of 3 wt. % and above would have a high
crush strength. Plots of the nitrogen pore size distribution at
clay levels from 0 to 1 wt. % are shown at FIG. 2, and those for
clay levels between 0 and 6 wt. % are shown at FIG. 3.
[0226] FIG. 2 actually shows a decrease in the mesopore pore mode
at low levels of Laponite.RTM.. FIG. 3 shows a consistent shift to
higher mesopore pore modes at increasingly higher clay
concentrations between 2 and 5 wt. %. Table 3 shows a peaking of
total pore volume (TPV), average pore diameter (APD), and fresh and
steamed surface area (SA) peaks at a clay concentration of 5 wt.
%.
4TABLE 3 EFFECT OF THE LAPONITE .RTM. LEVEL ON THE FRESH AND
STEAMED PROPERTIES OF BOEHMITE Run No. 3 4 5 6 7 8 9 10 11 12 WT. %
Laponite .RTM. 0 0.5 1 2 3 4 5 6 8 10 % Conversion Active Alumina
83 NA 72 72 78 79 65 NA 68 NA To Boehmite *Crystallite Size (.ANG.)
128 114 99 81 94 79 62 63 74 69 DPI (%) 21 20 27 99 100 100 100 100
100 2 hours @ 537.8.degree. C. BETSA (m.sup.2/g) 179 263 289 317
279 311 315 290 295 286 Micro SA(m.sup.2/g) 0 0 0 0 0 0 0 0 0 0
Meso SA(m.sup.2/g) 179 263 289 317 279 311 315 290 295 286 Ave
P.D.(.ANG.) 149 90 95 122 197 153 188 112 89 88 Total P.V. (cc/g)
0.668 0.592 0.687 0.966 1.378 1.184 1.479 0.813 0.659 0.629 **SA On
Dist (m.sup.2/g) 276 456 450 436 341 373 388 354 340 335 PV >
600 .ANG. (cc/g) 0.046 0.054 0.055 0.226 0.298 0.222 0.176 0.061
0.035 0.034 Mesopore Content (%) 34 16 22 31 55 68 67 47 42 37
Macropore Content (%) 8.6 10 9 21 26 26 15 8 6 6 Mesopore Pore Mode
(.ANG.) 70 39 39 140 206 200 180 103 120 125 % Increase In Pore
Mode N/A -45 -45 100 194 186 154 47 71 79 4 hours @ 800.degree.
C.(20% STEAM) BETSA (m.sup.2/g) 112 131 150 184 182 198 228 209 213
203 Micro SA (m.sup.2/g) 0 Meso SA (m.sup.2/g) 112 Ave. P.D.
(.ANG.) 230 Total P.V. (cc/g)) 0 643 SA On Dist. (m.sup.2/g) 142.5
PV > 600 .ANG. (cc/g) 0.07 ***% SA Ret. 62.6 49.8 51.9 58 65.2
63 7 72.4 72.1 72.2 71 Note Total N.sub.2 Pore Volume Measured at a
Relative Pressure of 0.995 P/Po. *= After Aging Slurry at
100.degree. C. for 24 Hours **= Surface Area Calculated from
N.sub.2 Pore Size Distribution for Pores Having Pore Diameter
20-600 .ANG. ***= % Surface Area Retained After Steaming
EXAMPLE 3
[0227] This example illustrates the effect of drying conditions and
total volatiles (TV) measured at 954.4.degree. C. (1750.degree. F.)
on the dispersability of the synthetic hectorite and accordingly
the alumina product.
[0228] A two gallon autoclave batch of synthetic hectorite was
prepared in accordance with Example 2 of U.S. Pat. No.
4,049,780.
[0229] After autoclaving, the gel slurry of synthetic hectorite was
filtered, washed with water and divided into Samples 1 to 4 as
follows:
[0230] (1) held as filter cake, TV=83.43%
[0231] (2) oven dried overnight at 100.degree. C. (212.degree. F.).
TV=12.83%
[0232] (3) spray dried (S.D.) at 130.degree. C. outlet.
TV=19.38%
[0233] (4) spray dried at 180.degree. C. outlet. TV=15.45%
[0234] Spray dried Samples 3 and 4 were prepared by reslurrying the
filter cake to about 2% solids before spray drying in a small bench
top spray dryer.
[0235] Four separate alumina/synthetic hectorite composites were
prepared in accordance with Example 2 but using 3 wt. % of one of
the synthetic hectorite Samples 1 to 4. The solids content of each
clay/alumina slurry was 17 wt. %. More specifically, each of the
above synthetic hectorite Samples 1 to 4 were slurried in water
with rapid agitation for 1 hour. Calcined alumina was then added to
each slurry and boiled for 24 hours under reflux with good
agitation. The effect on the alumina pore volume of the synthetic
hectorite is shown at Table 4, Runs 13 to 16. The Total Pore Volume
of the boehmite product increases as the dispersability of the
synthetic hectorite increases. It was visually noted that the water
dispersed synthetic hectorites increased in clarity (and hence
dispersity) in the order: filter cake <oven dried <S.D. @
130.degree. C. <S.D. @ 180.degree. C. which is the order of
increasing pore volume, average pore diameter and dispersability
index of the alumina. Accordingly, the shift in pore volume can be
controlled by the level of dispersible swelling clan used and/or
the degree of dispersion of the swelling clay. The degree of
dispersion, or the size of the clay particles in the dispersion,
can be controlled by the clay synthesis conditions (molar input
ratios, autoclave temperature, etc.) or drying conditions. Note
further that the fresh and steamed S.A.'s of Sample 4 is still
higher than Sample 1 while achieving a much higher TPV.
5TABLE 4 EFFECT OF SYNTHETIC HECTORITE DRYING CONDITIONS ON THE
SURFACE PROPERTIES OF BOEHMITE FROM ACTIVE ALUMINA @ 3% CLAY RUN
NO. 13 14 15 16 Synthetic Hectorite Sample # 1 2 3 4 Type of Drying
Not Dried Oven Dried Spray Dried Spray Dried (Filter Cake)
(Overnight At 212.degree. F.) At 130.degree. C. At 180.degree. C.
Clay TV 83.43% 12.83% 19.38% 15.45% Wt. % Clay Added 3% 3% 3% 3%
Alumina Properties [Calcined 2 hours @ 537 8.degree. C.
(1000.degree. F.)] BET Surface Area (m.sup.2/g) 261 295 285 264
Ave. Pore Diameter (.ANG.) 119 172 195 216 Total Pore Volume (cc/g)
0.773 1.268 1.387 1.428 Dispersability Index (%) 20 36 62 94
Hydrothermal Stability 4 Hrs @ 800.degree. C. 20V % 195 238 230 213
Steam Surface Area (m.sup.2/g)
EXAMPLE 4
[0236] This example illustrates the impact of dispersability on the
morphological properties of the composite as mediated by the clay
forming reaction temperature.
[0237] A first synthetic hectorite sample labeled SH-1, designated
Run 16-1. was prepared generally in accordance with Example 3 at
inputs of 1.49 moles SiO.sub.2, 1.0 mole MgO, 0.06 mole Li, 0.08
mole Na by adding 97.9 gm silicic acid (H.sub.4SiO.sub.4), 58.3 gm
Mg(OH).sub.2, 2.55 gm LiCl, and 4.7 gm NaCl to 1, 169 gm H.sub.2O
and boiled at reflux for 24 hours. A second synthetic hectorite
(SH-2), designated Run 16-2, was prepared using inputs of 87.4 gm
silicic acid. 58.3 gm Mg (OH).sub.2 and 10.5 gm LiCl added to 1,083
gm H.sub.2O and hot aging in a plastic bottle for about 24 hours at
101.7.degree. C. (215.degree. F.). Both samples had X-ray
diffraction patterns of hectorite. A slurry of each clay was
prepared by blending in water for 2 minutes, and to this slurry was
added 291 gm, dry basis, CP-3 calcined alumina and 1.5 gm sodium
gluconate. The synthetic clay/alumina weight ratio was 3/97. This
slurry was boiled under reflux for 24 hours. filtered and oven
dried. It was observed during reflux of the synthetic hectorite
starting materials for both SH-1 and SH-2, that the particles were
coarse and did not disperse to a colloidal sol.
[0238] Nitrogen pore size distribution results, are summarized at
FIG. 4 along with the plot from the control of Run 3. These results
illustrate that this alumina prepared with non-dispersible or
poorly dispersed synthetic hectorites (SH-1 and SH-2) do not have
the same shift in nitrogen pore size distribution of even the
control without any synthetic hectorite. The amounts of reactants
for SH-1 and SH-2 are summarized at Table 5.
6 TABLE 5 16-1 16-2 RUN NO. Sample No. SH-1 Sample No. SH-2
Reactants (gms) (gms) H.sub.4SiO.sub.4 97.9 87.4 Mg(OH).sub.2 58.3
58.3 LiCl 2.55 10.5 NaCl 4.7 0 H.sub.2O 1,169 1,083
[0239] In general, the higher the synthetic hectorite reaction
forming temperature or the longer the time, the higher will be its
dispersability. Thus, reaction forming temperatures of at least 150
to 200.degree. C. are preferred. Such temperatures are achievable
with an autoclave.
EXAMPLE 5
[0240] This example illustrates the effect of employing highly
purified non-fluorinated hectorite in place of a synthetic
hectorite. Two samples of highly purified natural hectorite were
obtained from the American Colloid Co. These clays. Hectalite 200
(designated separately NH-1) and Hectabrite DP (Designated NH-2).
were dispersed for 1 minute in a blender. Calcined alumina and
sodium gluconate were then added to each dispersion to give 3% clay
and 97% calcined alumina (CP-3, ALCOA). The gluconate level was 0.5
wt. % on an alumina basis. Both slurries were boiled under reflux
for 24 hours with agitation, filtered, and oven dried. Nitrogen
pore size distribution results are reported at FIG. 5. This
procedure was repeated using clay samples SH-1 and SH-2 and
designated Runs 20 and 21.
[0241] A reference alumina sample designated CE-2 was also prepared
in accordance with Example 5, except the clay was omitted.
[0242] A comparison of the plots of FIGS. 1 and 3 with those of
FIG. 5 illustrate only a slight shift of the mesopore mode to
higher diameters when using natural hectorite versus synthetic
hectorite (Runs 20-21). Other morphological properties of the
natural hectorite samples (Runs 18-19), the sample from Run 7, and
Comparative Sample CE-2 (Run 17) are also reported at Table 6.
7TABLE 6 EFFECT OF VARIOUS HECTORITES ON BOEHMITE PORE STRUCTURE
RUN NO. 17 18 19 20 21 7 SAMPLE # CE-2 NH-1 NH-2 SH-1 SH-2 TABLE 3
Run 7 CLAY 0 HECTALITE HECTABRITE SYN HECT SYN HECT LAPONITE .RTM.
WT % Added 0 4 4 3 3 3 BET SA(m.sup.2/g) 179 235 221 257 263 279
Mic SA (m.sup.2/g 0 0 0 0 0 0 Meso SA(m.sup.2/g) 179 235 221 257
263 279 Ave. P.D. (.ANG.) 149 166 127 106 102 197 Total PV (cc/g)
0.668 0.979 0.702 0.681 0.674 1.378 SA On Dist. (m.sup.2/g) 275.9
319.6 276.8 429.9 441.2 341 PV > 600.ANG. (cc/g) 0.046 0.143
0.039 0 061 0.049 0.298
EXAMPLE 6
[0243] This example illustrates the effect of a synthetic hectorite
on hydrothermal stability of a different calcined alumina. Thus, a
calcined alumina available from Porocel under the tradename AP-15
was used to make composites of Boehmite/Laponite.TM. using the
procedure of Example 1, except the levels of dispersible hectorite
(Laponite.TM. RD) were varied at 0, 1.5, and 3 wt. % and no sodium
gluconate was employed (Run 22). The results indicate good
hydrothermal stability was obtained, with or without added
gluconate. The stability is very comparable to that obtained with
the CP-3 alumina.
[0244] The resulting samples were aged in steam (20%) for 4 hours
at 800.degree. C. and the BET surface area in m.sup.2/g determined.
In addition, composite samples were prepared in accordance with
Example 1 using CP-3 alumina except that the Laponite.RTM. content
was varied at 0, 0.1, 0.2, 0.25, 1.5, 2, 3 and 5 wt. % and the
resulting products aged as described above for the AP-15 derived
samples. The results are shown at FIG. 6 as Run 23.
EXAMPLE 7
[0245] This example illustrates the effect of varying the point of
addition of synthetic Laponite.RTM. before and after rehydration of
the calcined alumina.
[0246] A batch of boehmite from calcined alumina was prepared as
follows: to 1888 gms H.sub.2O in a 3L glass container was added
24.4 gms of a 10 wt. % sodium gluconate solution and then 480 gms,
dry basis, of calcined CP-3 alumina from ALCOA. This slurry was
boiled for 24 hours under reflux to rehydrate the alumina. The
rehydrated alumina was then divided into 5 equal portions. To each
was added varying amounts of Laponite.RTM. RD (Laporte) at 0, 2, 4,
6 and 8 wt. %. The surface area of these materials was determined
after aging 4 hours in 20% steam at 800.degree. C. and the results
reported at FIG. 7 as Run 24. The above procedures were repeated
except that the Laponite.RTM. was added at 0, 0.25, 1.0, 2.0, 2.25,
3.0, 3.75, 4.0, 5.0, 6.0, 8.0, and 10 wt. % amounts prior to
refluxing the alumina, i.e., prior to rehydration. The resulting
products were then also aged in steam (20%) for 4 hours at
800.degree. C. the BET surface area determined and results
summarized at FIG. 7. Run 25. As can be seen therefrom addition of
the dispersible hectorite before rehydration (Run 25) gives a more
hydrothermally stable product versus addition after rehydration
(Run 24). It is thought that this is due to the higher fresh
surface area, pore volume and average pore diameter of this
product, as well as the better dispersion of the clay within the
alumina, when it is added at the start of the rehydration.
EXAMPLE 8
[0247] This example illustrates the effect on hydrothermal
stability of pre-milling the slurry containing the dispersible
synthetic hectorite and a calcined alumina (CP-3. ALCOA).
[0248] To 8,331 gm H.sub.2O was added with rapid agitation 51.9 gm
Laponite.RTM. RD (Laporte, TV=13.26%). The slurry was aged at room
temperature with agitation for 20 minutes to disperse the clay. A
substantially clear solution formed indicating a good, colloidal
dispersion of the clay. To this was added 1,616.7 gm CP-3 (TV=10%)
with good agitation. The slurry containing 3 wt. % Laponite.TM. was
then milled under severe (80% media, 0.75 1/1 min.) conditions in a
4L DRAIS mill. The milled slurry was boiled under reflux for 24
hours and a portion filtered and oven dried. The resulting sample
is designated Run 28. The designation 0.75 L/l min refers to an
input/output of 0.75 liters per minute to and from the mill.
[0249] The above procedure was repeated except the premilling was
omitted. This sample is designated Run 27.
[0250] In addition, a control was prepared wherein the Laponite was
omitted and no premilling was employed. This sample was designated
Run 26.
[0251] All three samples were then divided into two parts and the
first part aged at 4 hours in 20% steam at 800.degree. C. and the
second part aged at 537.8.degree. C. for 2 hours. The surface area
was then determined for each aced sample. The hydrothermal
stability results are summarized at Table 7 and the nitrogen pore
properties depicted at FIG. 8.
[0252] Table 7 indicates that premilling leads to a product with
much higher fresh surface area and steamed surface area than the no
clay base case or the unmilled sample with the same level of
dispersible clay. Nitrogen pore size distribution results indicate
premilling gives a small shift to more pores of smaller diameter
but higher TPV.
8TABLE 7 3% Laponite .RTM. 3% Laponite .RTM. with Milling 0%
Laponite .RTM. w.o. Milling Before Aging 26 27 28 RUN NO. SA
(m.sup.2/g) SA (m.sup.2/g) SA (m.sup.2/g) 4 hrs @ 800.degree. C. SA
115-119 195-210 281 2 hrs @ 537.8.degree. C. 199 279 345 Ave P.D.
(.ANG.) 153 197 169 Total Pore Vol. (cc/g) 0.761 1.378 1.461
Mesopore Pore Mode 69 111 108 (.ANG.) % Increase in N/A 61 56
Mesopore pore Mode
EXAMPLE 9
[0253] This example illustrates the effect and degree of
pre-dispersion achieved with a laboratory preparation of synthetic
hectorite dried to a low TV (9.64%).
[0254] The synthetic hectorite was prepared by slowly adding a
solution of 75.3 gm Na.sub.2CO.sub.3 dissolved in 289 gm H.sub.2O
to a solution of 183.5 gm Mg SO.sub.4.circle-solid.7H.sub.2O+3.4 gm
LiCl. Then a solution of 267.4 gm silicate (27.11% SiO.sub.2)
diluted with 826 gm H.sub.2O was added over a half hour period. The
resulting gel slurry was boiled for 30 minutes to remove carbonate
then autoclaved for 2 hours at 200.degree. C. filtered, washed on
the filter with 1L 65.6.degree. C. (150.degree. F.) deionized water
and dried at 135.degree. C.
[0255] Portions were reslurried in water as follows:
9 Run 29 stir with moderate agitation for 30 minutes Run 30
disperse with Silverson mixer for 10 minutes at 10,000 RPM Run 31
stir for about 18 hours with magnetic stirring bar.
[0256] To each of the above slurries was added enough calcined
alumina (CP-3, ALCOA) to make a 15% solids slurry with 3 wt. % of
the synthetic hectorite and 97% alumina. The slurry was boiled for
24 hours under reflux with agitation. The slurry was filtered and
over dried at 137.8.degree. C. (280.degree. F.). The average pore
diameter of each product derived from Runs 29 to 31 was measured
after 2 hours at 537.8.degree. C. (1000.degree. F.) calcination.
The surface area and TPV were determined and the results summarized
at Table 8.
[0257] The average pore diameter increased from 147 to 159 to 176A
for Runs 29 to 31 respectively, indicating better dispersion is
achieved as dispersing time and/or severity was increased. It is
believed that this sample was difficult to disperse due to its
relatively low total volatiles of 9.64%. Thus, dispersability of
the clay can be enhanced by controlling the TV, the degree of clay
dispersion, or the clay crystallite size, which in turn control the
average pore diameter of the alumina.
10TABLE 8 THE EFFECT OF THE DEGREE OF DISPERSION OF THE SYNTHETIC
HECTORITE ON THE TOTAL N. PORE VOLUME AND AVERAGE PORE DIAMETER OF
THE BOEHMITE PREPARED BY REHYDRATION OF ACTIVE ALUMINA RUN NO. 29
30 31 WT. % Synthetic Hectorite 3 3 3 Clay Dispersion 30 Min. 10
Min. 18 Hrs. Mild Agit. Silverson Mild Agit. (10,000 rpm) 2 hrs @
537.8.degree. C. (1000.degree. F.) Alumina Properties Surface Area
(m.sup.2/g) 286 284 284 Pore Diameter (.ANG.) 147 159 176 N.sub.2
Pore Vol. (cc/g) 1.05 1.13 1.23 Total volatiles of the synthetic
hectorite, sample employed for Runs 29-31 was only 9.64%, and is
believed to have made this clay difficult to fully disperse
regardless of the degree of agitation.
Comparative Example 2
[0258] This example illustrates the effect of non-swellable clays
such as Kaolin, or calcined Kaolin on pore structure.
[0259] Example 1 was repeated except that the clay employed was
kaolin or calcined kaolin at the amounts reported in Table 9. The
resulting composites are designated as Run 33 (kaolin), Run 34
(calcined kaolin at 6 wt. %), and Run 35 (calcined kaolin at 12 wt.
%). The calcination of the kaolin was conducted at 900.degree. C.
for 0.66 hours. The surface properties of these materials were
measured as was the fresh surface area and the results reported at
Table 9. A control alumina with no clay was also employed prepared
by the same method and designated Run 32. The amounts of kaolin
present in the composite particles is also reported at Table 9.
Nitrogen desorption data for Runs 32 to 35 is also reported at FIG.
9. As can be seen from Table 9 and FIG. 9. the kaolin actually
caused a reduction in average pore diameter (APD) and Total Pore
Volume relative to the control but an increase in surface area.
Kaolin is a non-swellable clay.
EXAMPLE 10
[0260] This example illustrates the effect on pore properties of
using the less preferred montmorillonite clay.
[0261] Comparative Example 2 was repeated except that
montmorillonite clay, available from Southern Clay Products under
the tradename Gelwhite L. replaced the kaolin clay at 6 wt. % (Run
36) and 12 wt. % (Run 37). The control at 0 wt. % clay is
designated Run 32. The results are summarized at Table 9 and FIG.
10. As can be seen therefrom, the alumina pore properties and
surface area are higher at 6 wt. % than 12 wt. % clay. Moreover,
the mesopore pore mode does not appear to shift to the richt and
the pore size distribution spreads out. This is believed to be
attributable to the fact that montmorillonite is difficult to
disperse well without some other treatment such as significant
milling to reduce the particle size, ion-exchange, or the use of
dispersants such as tetra sodium pyrophosphate.
EXAMPLE 11
[0262] Comparative Example 2 was repeated except that sodium
silicate replaced the kaolin clay at 0.5 wt. % (Run 39) and 1 wt. %
(Run 38). The control without silicate is Run 32.
11TABLE 9 EFFECT OF VARIOUS ADDITIVES ON THE BOEHMITE PORE
STRUCTURE RUN NO. 32 33 34 35 36 37 38 Clay None Kaolin Calcined
Calcined Montmo- Montmo- % SiO.sub.2 from Kaolin Kaolin rillonite
rillonite Silicate Wt. % 0 12 6 12 6 12 1 2 hrs. @ 537.8.degree. C.
(1000.degree. F.) Properties BET Surface Area (m.sup.2/g) 199 186
298 311 246 239 281 Ave. Pore Diameter (.ANG.) 153 129 91 77 138
116 102 Total N.sub.2 Pore Volume (cc/g) 0.761 0.598 0.675 0.603
0.848 0.692 0.718 Mesopore Pore Mode (.ANG.) 69 58 39 39 70 70 40 %
Increase in Mesopore Pore Mode N/A -16 -44 -44 1 1 -42
[0263] The pore properties and surface area were tested and the
results summarized at Table 9 (for Run 38) and FIG. 11. As can be
seen therefrom the silicate actually induced a sharp shift of the
mesopore pore mode to smaller pore diameters. Thus, the silicate
derived composites can be blended with the hectorite derived
composites to shift the pore structure as desired for each intended
application.
EXAMPLE 12
[0264] This example illustrates the effect on hydrothermal
stability of milling the calcined alumina prior to rehydration in
the presence of swellable clay.
[0265] Thus, Example 8. Run 28 was repeated and the combined slurry
of Laponite.RTM. (at 3 wt. %) and calcined alumina was milled prior
to rehydration and designated Run 42. After reflux for 24 hours at
100.degree. C. (212.degree. F.) the boehmite was filtered and oven
dried at 140.degree. C. for 6 hours. Portions were calcined at
800.degree. C. in an approximate 20% steam atmosphere for varying
times and then the surface areas measured. The above procedure was
repeated except that the milling step was omitted and the product
designated Run 41. A control containing no Laponite.RTM. and no
milling step was also made and designated Run 40 and subjected to
the same steam treatment and surface area determinations. The
results are summarized at FIG. 12. FIG. 13 expresses the data
points of each Run of FIG. 12 as a percent of the surface area
obtained on a fresh sample, heated for 2 hours at 537.8.degree. C.
(1000.degree. F.) (i.e., 0 hours heated in steam). This percentage
is referred to as a % surface area retention. As can be seen
therefrom. the surface area stability increases in the order 0%
Laponite.RTM. (Run 40) <3% Laponite.RTM. (Run 41) <3%
Laponite.RTM. and milling (Run 42).
EXAMPLE 13
[0266] This example illustrates the effect of post-synthesis
addition of Na silicate to boehmite derived from rehydrated
calcined alumina.
[0267] A sample of calcined alumina available from ALCOA under the
tradename CP-3 (Run 43) and a sample of calcined alumina available
from Porcel under the tradename AP-15 (Run 44) were each separately
slurried in water containing 0.5 wt. % (alumina basis) sodium
gluconate, at a solids content of 17 wt. % and hot aged for 24
hours under reflux. Both batches were then divided up and varying
amounts of sodium silicate added. aged for about 30 minutes at
21.degree. C. the pH adjusted to 9.0 with 4% H.sub.2SO.sub.4,
filtered, reslurried with ammonium sulfate to remove Na.sub.2O,
filtered, water washed and dried. Each sample was steamed for 4
hours at 800.degree. C. in an atmosphere of about 20V % steam and
the surface area measured.
[0268] The results on the products of each run are summarized at
FIG. 14. As can be seen therefrom the silicate significantly
enhances the hydrothermal stability of the boehmite samples.
EXAMPLE 14
[0269] This example illustrates the effect of adding silicate to
the composite of the present invention after formation thereof.
[0270] Two batches of boehmite were prepared using 3 wt. % (Run 45)
and 5 wt. % (Run 46) Laponite.RTM. RD (Laporte) as the source of
dispersible clay. Slurries of the Laponite.RTM. were prepared by
adding the clay to water with rapid agitation and mixing for 20
minutes. Sodium gluconate was added at 0.5 wt. % (alumina basis)
followed by addition of CP-3. a calcined alumina from ALCOA, Each
slurry was boiled under reflux for 24 hours with agitation,
filtered and oven dried overnight at 137.8.degree. C. (280.degree.
F.). Portions of each product were reslurried in water, sodium
silicate added and the mixture aged 30 minutes at 21.degree. C. The
pH was adjusted to 9.0 with 4% H.sub.2SO.sub.4, filtered, exchanged
as a slurry with ammonium sulfate to remove Na.sub.2O, filtered
water washed and oven dried at 137.8.degree. C. (280.degree. F.).
Each sample was then subjected to contact with 20 wt. % steam
atmosphere for 4 hours at 800.degree. C. and the surface area
determined. A plot of wt. % SiO.sub.2 versus steamed surface area
is provided at FIG. 15. As can be seen therefrom, very high surface
areas were obtained. Moreover, a comparison of these steamed
surface areas with the clay free samples from Example 13 (FIG. 14).
is provided at FIG. 16. As can be seen therefrom, improved surface
areas were obtained by combining the addition of the dispersible
clay with post-synthesis addition of silicate. It is believed that
part of the reasons for the higher steamed surface area of the
aluminas with dispersible clay is the higher fresh surface area,
higher pore volume and higher average pore diameter.
EXAMPLE 15
[0271] This example illustrates the effect of post-synthesis
silicate addition to an alumina prepared with a poorly dispersed
synthetic hectorite prepared at only 100.degree. C. (212.degree.
F.) (the lower prep temperature inducing a much lower degree of
dispersability).
[0272] A batch of synthetic hectorite was prepared by adding 97.9
gm silicic acid (H.sub.4SiO.sub.4) to 1169 gm H.sub.2O in a 3L
resin kettle under agitation. To the kettle was added under
agitation. 58.3 gm Mg (OH), 2.55 gm LiCl, and 4.7 gm NaCl. The
slurry was refluxed for 24 hours, filtered, washed three times with
water at 65.6.degree. C. (150.degree. F.) and dried at
137.8.degree. C. (280.degree. F.). An X-ray diffraction pattern
very similar to that of Laponite.RTM. RD was obtained. Enough of
this dried material was blended in 800 ml H.sub.2O for 2 minutes to
give 3% of the final alumina weight, and to disperse it as much as
possible. In contrast to Laponite.RTM. RD, an opaque slurry was
obtained, indicative of a low degree of dispersion. This slurry was
added to a 3L resin kettle along with 0.5 wt. % sodium gluconate (
alumina basis), and additional H.sub.2O to give a 17% solids
slurry. CP-3 (calcined alumina from ALCOA) was then added. This
slurry was boiled under reflux for 24 hours, filtered and dried at
137.8.degree. C. (280.degree. F.). Portions were reslurried in
water, and varying amounts of silicate added as reported at FIG.
17, Run 49. Each sample was steamed for 4 hours, 800.degree. C., in
approximately 20% steam and the surface areas determined.
[0273] The above procedure was repeated except that highly
dispersed Laponite.RTM. RD replaced the synthetic hectorite made
and used for Run 49. Each sample of the resulting product was
tested for surface area and the results designated Run 48. These
results are plotted in FIG. 17.
[0274] A control was also made following the procedures of Run 49.
except no clay was employed. The surface areas were plotted in FIG.
17 and designated Run 47.
[0275] As can be seen from FIG. 17, the surface area stability
increases in the order of no clay+silica<poorly dispersed
clay+silica<well dispersed clay+silica.
EXAMPLE 16
[0276] This example illustrates the effect of premilling the slurry
containing calcined alumina and dispersible clay before rehydration
and with post synthesis addition of sodium silicate.
[0277] A slurry was prepared by dispersing 51.9 gm Laponite.RTM. RD
(TV=13.26%) in 8.331 gm H.sub.2O with rapid agitation for 20
minutes, followed by addition of 1.616.7 gm of CP-3 ( a calcined
alumina from ALCOA. TV-10%). The resulting slurry was milled in a
4L DRAIS mill at a rate of about 1L/minute with a glass media
loading of about 60%. The slurry was hot aged for 24 hours at
boiling under reflux, filtered and oven dried. Samples of this
boehmite alumina were reslurried in water, with varying amounts of
sodium silicate as reported at Table 10, aged 1/4 hour at
21.degree. C., pH adjusted to 9.0 with 4% H.sub.2SO.sub.4, filtered
and designated Run 52. The above procedure was repeated except that
the milling step was omitted and resulting samples designated Run
51. A control was also prepared except that the milling step and
the silica and clay addition was omitted. The control was
designated Run 50. Each of the samples of Runs 50 to 52 was
reslurried in water containing ammonium sulfate for 1/4 hour,
filtered, water washed and oven dried. This exchange was made to
reduce Na.sub.2O to a low (<0.25 wt. %) level. Samples were then
calcined for 4 hours at 800.degree. C. in a 20V % steam atmosphere.
The effects of the silicate level as well as milling/not-milling
and the presence of the dispersible hectorite on the steamed
surface area is summarized at Table 10. Milling gives the highest
surface area with or without added silicate.
12TABLE 10 50 51 52 ALUMINA ALUMINA ALUMINA FROM CP-3 FROM CP-3
WITH MILLING (No-Clay) W.O. MILLING BEFORE AGE (No-Milling) (3%
Clay) (3% Clay) SA SA SA RUN NO. (m.sup.2/gm) (m.sup.2/gm)
(m.sup.2/gm) 4 hrs @ 800.degree. C. SA 115-119 195-210 281 With 4%
SiO.sub.2 179 250 302 With 8% SiO.sub.2 195 279 311 2 hrs @
537.8.degree. C. (1000.degree. F.) BET SA 199 279 345 Ave. P.D. 153
197 169 Total Pore Volume 0.761 1.378 1.461 % SA Retention (On
SiO.sub.2 SA Basis) 0% SiO.sub.2 58.8 72.4 81.4 4% SiO.sub.2 89.9
89.6 87.5 8% SiO.sub.2 98 100 90.1
EXAMPLE 17
[0278] This example illustrates the effect of adding sodium
silicate before or after rehydration (hot aging) of the calcined
alumina slurry.
[0279] Slurries were prepared of the calcined alumina (CP-3, ALCOA)
with varying silicate levels and then hot aged for 24 hours at
boiling and under reflux. The resulting samples are grouped as Run
54. Slurries were also prepared using calcined alumina only
(designated Run 53 ), or calcined alumina to which 3% of a
dispersible Hectorite (Laponite.RTM. RD) was added before the hot
aging (designated Run 55). The latter two preparations were treated
with varying amounts of silicate after the hot age. which amounts
are shown at FIG. 8. All samples were exchanged with ammonium
sulfate to reduce Na.sub.2O to a low level (<0.25 wt. %) before
steaming at 800.degree. C. for 4 hours in an atmosphere of about
20% steam. The surface areas of the resulting products for Runs 53
to 55 are reported at FIG. 18. The surface area results indicate
the addition of silicate improves the hydrothermal stability of all
the samples. However, the surface areas follow generally in the
order Al.sub.2O.sub.3+3% Laponite.RTM.>silicate addition after
age>silicate addition before age. Addition of silicate before
the hot age also reduces the pore volume/pore diameter of the
Boehmite.
EXAMPLE 18
[0280] This example illustrates the effect of adding silicate after
rehydration on the steamed pore structure of a boehmite
alumina/Laponite.RTM. composite.
[0281] Samples of a 3% Laponite.RTM. containing boehmite with
varying silicate levels of 0 wt. % (Run 56), 2 wt. % (Run 57), 4
wt. % (Run 58) and 8 wt. % (Run 59), were prepared as described in
Example 14. After 4 hours at 800.degree. C. treatment in 20% steam,
the nitrogen pore size distributions were measured. The results are
reported at FIG. 19. FIG. 19 shows only minor changes in pore
distribution between 0, 2, 4% added silicate, however, at 8%
silicate, the pores do shift to a lower average pore diameter.
EXAMPLE 19
[0282] This example illustrates the preparation of the
alumina/swellable clay composite which is used in the following
example to make agglomerates therefrom. 7.014 g OB (Original Basis
not corrected for TV) (3% by weight, based on the combined weight
of alumina and clay) of a synthetic hectorite Laponite.RTM. was
slurried in 350 gallons of city water at ambient temperature. The
slurry was mixed in an open tank with a 4 paddle agitator for 30
minutes at maximum agitation (about 300 rpm) to assure a good
dispersion. Then, 234 kg (515 pounds) OB of Alcoa CP-3 activated
alumina were slowly added to the slurried Laponite.RTM.. After all
the CP-3 was added, the slurry was heated to 93.3.degree. C.
(200.degree. F.) where it was held for 24 hours. The slurry was
filtered and washed with 65.6-71.1.degree. C. (150-160.degree. F.)
city water on a three-wash-zone Eimco belt filter. The filter cake
was spray-dried at 371.1.degree. C. (700.degree. F.)
inlet/121.1.degree. C. (250.degree. F.) outlet temperature.
[0283] The resulting product is designated Sample No. AX-1.
[0284] A summary of the properties of AX-1 is provided at Table 11
and a plot of its nitrogen pore size distribution is provided at
FIG. 20. The data on AX-1 in FIG. 20 is designated Run 60.
Comparative Example 3
[0285] A control sample of boehmite alumina was synthesized as
follows.
[0286] To 4.950 parts by volume of water heated in a reactor to
63.3.degree. C. (146.degree. F.) under constant agitation was added
150 parts by volume of a 7.0 wt. % solution of aluminum sulfate as
Al.sub.2O.sub.3 and the resultant mixture stirred for four minutes.
Two separate solutions were then simultaneously fed to the reactor.
The first solution was 7.0 wt. % aluminum sulfate as
Al.sub.2O.sub.3 in water and the second solution was 20 wt. %
aluminum as Al.sub.2O.sub.3 sodium aluminate in water. Upon
completion of the addition, the weight ratio of aluminum
sulfate:aluminum sodium sulfate in the reactor was 5:3. The flow
rates are adjusted during addition to provide a pH of 7.6. When the
7.6 pH target is met, the aluminum sulfate addition is terminated
and the sodium aluminate addition is continued until a pH of 9.3 is
reached. The sodium aluminate addition is then terminated, and the
reactor contents aged for 2 hours at 66.degree. C. (150.degree. F.)
The precipitated product is then filtered, washed and spray dried
at 371 .degree. C. (700.degree. F.) inlet temperature 135.degree.
C. (275.degree. F.) outlet temperature to form an aluminum powder
which is sized to a particle size of 10-20 microns. The resulting
product is designated CAX- 1. The properties thereof are summarized
at Table 11 and FIG. 20. The data on CAX-1 in FIG. 20 is designated
Run 61.
13 TABLE 11 RUN NO. 60 61 Sample # AX-1 CAX-1 TV @ 1750.degree. F.
wt. % 22.0 29.4 SA m.sup.2/g 291 292 N.sub.2PV (0.967 p/p.sup.0)
cc/g 1.16 0.94 DPI n/a 31 APS .mu. 9.8 15.9 Na.sub.2O wt. % 0.41
0.03 SO.sub.4 wt. % 0.04 0.82 Fe wt. % 0.05 0.01 Mesopore Pore Mode
.ANG. 150 65.7 % increase in Mesopore Pore Mode % 60 N/A
[0287] As can be seen from Table 11 and FIG. 20, AX-1 (Run 60) and
CAX-1 (Run 61) have similar surface areas, but AX-1 has about 20 v
% more pore volume than CAX-1 and the mesopore pore mode of AX-1 is
about 150 Angstroms compared to 50-70 Angstroms for CAX-1.
EXAMPLE 20
[0288] Part A
[0289] This example illustrates the preparation of a
pre-impregnation of AX-1 prior to extrusion.
[0290] 13.6 kg (30 lbs.) OB of AX-1 alumina were mixed in an Eirich
mixer with 10.5 kg of city water, 6.2 kg of ammonium molybdate
solution and 2.0 kg of commercial grade (15% Ni) nickel nitrate
solution. The ammonium molybdate solution was prepared by
dissolving 2.2 kg of commercial ammonium dimolybdate crystals in
4.0 kg of deionized water. The mix was extruded in a 4" Bonnot
pilot plant extruder to form 0.04" diameter extrudates using
conventional extrusion conditions. The extrudates were dried at
121.1.degree. C. (250.degree. F.) for 4 hours and calcined at
648.9.degree. C. (1200.degree. F.) for 1 hour. The resulting
extrudate is designated EMAX-1 (Run 62).
[0291] Part B:
[0292] The pore property results of Part A of Example 20 were
normalized to a metals free basis and the results designated as Run
63. Samples are normalized herein to a metals free basis in
accordance with the following Equation: 2 M F B = ( X ) ( 100 ) (
100 - W ) ( Equation 6 )
[0293] Wherein X is this pertinent pore property such as PV (in
cc/g), or SA (m.sup.2/g)
[0294] W=the wt. % of catalytic promoter metal oxides such as Ni,
Co, and Mo oxide on the catalyst based on the wt. of porous
constituents of the catalyst. The weight of non-porous
constituents, e.g., non-porous diluents, of the catalyst extrudate
are not included in the wt. % calculation
[0295] and MFB=Metals Free Basis.
Comparative Example 4
[0296] Part A:
[0297] Example 20 of Part A was repeated except that the AX-1
sample from Example 19 was replaced with the CAX-1 sample of
Comparative Example 3. The resulting extrudate product is
designated EMCAX-1 (Run 68).
[0298] Part B:
[0299] The pore property results of Part A of Comparative Example 4
were normalized to a metals free basis and the results designated
Run 69.
[0300] Physical and compositional properties of the metal
impregnated catalyst samples EMAX-1 and EMCAX-1 are provided at
Table 12 and the mercury pore size distribution and other
properties of these samples is provided at Tables 13A and B.
[0301] A higher SiO.sub.2 is also noted due to the nature of the
dispersible clay contained in AX-1. A plot of the mercury pore size
distribution of each catalyst is shown in FIG. 21.
[0302] Of particular note is that SA and TPV of both Run 62 and Run
68 are similar. but that the pore mode for Run 62 is 1 45A compared
to only 65A for Run 68. These modes are very close to those of the
starting aluminas which is characteristic of the stabilizing effect
of pre-impregnated metals on the alumina properties. As can be
further seen from Tables 13A and B, pore diameters have shifted
from the <100 .ANG. in Run 68 to the 100-250 .ANG. region, and
more predominantly to the 130-250 .ANG. region for Run 62. In spite
of the shift and increase in pore mode, the total surface area and
total pore volume of Run 62 are similar to Run 68.
14TABLE 12 Metal Pre-Impregnated Extrudates Run No. 62 64 66 68
Sample ID EMAX-1 EMAX-2 EMAX-3 EMCAX-1 Alumina AX-1 AX-1 AX-1 +
CAX-1 Type CAX-1 2 parts + 1 part Catalyst Properties MoO.sub.3 wt.
% 14.1 14.9 14.1 13.6 NiO wt. % 3.1 3.5 3.1 3.3 SiO.sub.2 wt. %
0.66 0.61 0.51 0.08 Na.sub.2O wt. % 0.2 0.18 0.17 0.06 Fe wt. %
0.01 0.01 0.01 0.08 Particle mm 0.98 0.99 1.00 1.00 Diameter CBD,
lbs/ft.sup.3 35.4 32.1 34.5 .about.36 MaxPack Crush lb/mm 2.9 2.5
2.0 1.7 Strength CBD = Compacted Bulk Density
EXAMPLE 21
[0303] Part A:
[0304] The alumina sample AX-1 prepared in accordance with Example
19 was used to make a metal impregnated extrudate in accordance
with Example 20, Part A, except that the mix contained 300 g more
water in order to increase the amount of porosity in pores greater
than 250 .ANG. in diameter. The resulting extrudates are designated
EMAX-2 (Run 64).
[0305] Part B:
[0306] The pore property results of Part A of this Example were
normalized to a metals free basis and the results designated Run 65
and reported at Tables 1 3A and 13B.
15TABLE 13A Total Pore Volume* Ex or RUN Comp Ex <100 .ANG.
>100 .ANG. >130 .ANG. >150 .ANG. >250 >500 No Sample
No cc/g % cc/g % cc/g % cc/g % cc/g % cc/g % 62 EMAX-1 Ex20(a) 26
33 53 67 42 53 34 43 17 21 10 13 63 MFB-EMAX-1 Ex20(b) 31 32 9 64
67 1 51 53 2 41 43 21 21 5 64 EMAX-2 Ex21(a) 26 29 62 70 50 57 43
49 21 24 13 15 65 MFB-EMAX-2 Ex21(b) 32 29 5 76 70 5 61 56 8 53 48
9 26 23 9 66 EMAX-3 Ex22(a) 36 40 54 60 44 49 38 42 25 28 17 19 67
MFB-EMAX-3 Ex22(b) 43 40 65 60 53 48 9 16 42 2 30 27 8 68 EMCAX-1
CEx4(a) 44 51 38 44 33 38 31 36 27 31 24 28 69 MFB-EMCAX CEx4(b) 53
53 7 46 46 3 40 40 2 37 37 8 32 32 9 -1 70 EAX-4 Ex23 22 27 2 59 72
8 44 53 9 24 29 6 04 4 9 02 2 5 71 EAX-5 Ex24(a) 24 27 6 63 72 4 48
55 2 32 36 8 06 6 9 03 3 4 72 ICAX-2 CEx5 32 33 7 63 66 3 38 40 0
28 29 5 20 21 1 17 17 9 73 EMAX-5 Ex24(b) 11 15 1 62 84 9 52 71 2
43 58 9 05 6 8 03 4 1 74 EMAX-6 Ex25 16 17 6 75 82 4 59 64 8 50 54
9 26 28 6 16 17 6 75 EMCAX-2 CEx6 18 22 5 62 77.5 0 42 52 31 38 8
18 22.5 15 18 8 Total Pore Volume* Ex or 100- RUN Comp Ex >1200
>1500 >4000 130 .ANG. 130-250 .ANG. No Sample No cc/g % cc/g
% cc/g cc/g % cc/g % 62 EMAX-1 Ex20(a) 07 9 06 7 6 03 13 13 9 31 31
6 63 MFB-EMAX-1 Ex20(b) 08 8 9 07 7 6 64 EMAX-2 Ex21(a) 11 12 11 12
04 15 13 6 36 33 65 MFB-EMAX-2 Ex21(b) 13 12 5 13 12 5 66 EMAX-3
Ex22(a) 12 13 11 12 04 12 11 1 23 21 1 67 MFB-EMAX-3 Ex22(b) 14 13
3 13 12 2 68 EMCAX-1 CEx4(a) 21 24 20 23 15 69 MFB-EMCAX CEx4(b) 25
25 6 24 24 4 -1 70 EAX-4 Ex23 0 0 0 0 0 15 18 9 40 49 71 EAX-5
Ex24(a) 02 2 3 01 11 01 15 17 2 42 48 3 72 ICAX-2 CEx5 14 14 7 13
13 7 06 25 26 3 18 18 9 73 EMAX-5 Ex24(b) 02 2 7 02 2 7 01 10 13 7
47 64 4 74 EMAX-6 Ex25 10 11 0 09 9 9 02 16 17 6 33 36 3 75 EMCAX-2
CEx6 12 15 0 12 15 0 04 0 20 25 5 0 24 29 5 *by Hg Porosimetry with
Contact Angle = 140.degree.
[0307]
16TABLE 13B Pore SA TPV RUN Ex or Comp Mode A m.sup.2/g cc/g No.
Sample Ex No (dV/dlogD) (Hg) (Hg) 62 EMAX-1 Ex20(a) 148 288 0.86 63
MFB-EMAX-1 Ex20(b) 148 348 .95 64 EMAX-2 Ex21(a) 135 290 88 65
MFB-EMAX-2 Ex21(b) 35 355 1.08 66 EMAX-3 Ex22(a) 119/63 312 90 67
MFB-EMAX-3 Ex22(b) 119/63 377 1.09 68 EMCAX-1 CEx4(a) 67 297 0.82
69 MFB-EMCAX-1 CEx4(b) 67 357 99 70 EAX-4 Ex23 148 212 81 71 EAX-5
Ex24(a) 158 222 .87 72 ECAX-2 CEx5 99 201 95 73 EMAX-5 Ex24(b) 191
166 73 74 EMAX-6 Ex25 115 180 91 75 EMCAX-2 CEx6 115 192 80 MFB =
Metals Free Basis
EXAMPLE 22
[0308] Part A
[0309] The catalyst was prepared in the same way as EMAX-1 (Run 62)
except that the alumina source was a physical powder blend of 9.09
kg (20 pounds) original batch (OB) of AX-1 (Run 60) and 4.5 kg (10
pounds) OB of CAX-1 (Run 61). The CAX-1 alumina was added to
increase macroporosity (pores>250 .ANG.) in the catalyst. The
resulting product is designated EMAX-3 (Run 66) and the properties
thereof are summarized at Tables 12 and 13A and B. and FIG. 21. As
can be seen therefrom, the addition of CAX-1 adds pores in <100
Angstrom region and the <250 region becomes bimodal.
[0310] Part B
[0311] The pore properties of the sample of Part A were normalized
to a metals free basis and the results designated Run 67 and
reported at Tables 13A and B.
EXAMPLE 23
[0312] This example describes a procedure of making the alumina
base (only) of a catalyst that could be eventually finished into
catalyst via a "post-impregnation" process. The base for
post-impregnated catalysts is prepared by extruding/calcining the
alumina in the absence of promoter metals (Ni and Mo in this
case).
[0313] 30 pounds OB of AX-1 alumina were mixed with 31 pounds of
city water in a pilot scale Eirich mixer. The mix was extruded
using a 4" Bonnot extruder to form 0.04" diameter extrudates. The
extrudates were dried at 121.1.degree. C. (250.degree. F.) for 4
hours and then calcined at 732.2.degree. C. (1,350.degree. F.) for
1 hour.
[0314] The resulting product is designated EAX-4 (Run 70) and the
mercury pore properties shown at Tables 13A and B.
Comparative Exanmple 5
[0315] Example 22 was repeated except that the starting alumina was
CAX-1. The resulting product is designated ECAX-2 (Run 72). The
mercury pore properties are shown at Tables 13A and B.
[0316] Comparing Runs 70 with 72, it can be seen that Run 70 has
almost 70% of the TPV in the 100-250 Angstrom range, and the
majority (49%) in the 130-250 Angstrom range. It will be further
noted that Run 72 shifts the pore mode of the starting CAX-1
alumina (Run 61) from 65 Angstroms to 100 Angstroms in the
extrudate. The same is not true of Run 70 (FIG. 22) versus AX-1 of
Run 60 (FIG. 20) which both exhibit a pore mode at about 145
Angstroms. Moreover Run 70 exhibits about the same pore mode as
Runs 62 and 64 (FIG. 21). Thus, it appears the AX-1 alumina of the
present invention has the same pore mode whether pre- or
post-impregnated. It will be further noted that Run 70 has
essentially no porosity >250 Angstroms unlike its
pre-impregnated analog of Run 62.
EXAMPLE 24
[0317] Part A
[0318] Example 23 was repeated except that 14.5 kg (32 pounds) of
water (1 pound more than in Example 23) was employed in the mixture
to increase total porosity in the pores>250 Angstroms. The
resulting extrudate is designated EAX-5 (Run 71).
[0319] The compositional properties, particle diameter, and crush
strength of Runs 70 to 72 are summarized at Table 14, and the
mercury pore distribution of the samples of Runs 70-72 are
summarized at Tables 13A and B. The mercury pore distribution of
Runs 70-72 is also shown at FIG. 22.
[0320] Part B
[0321] The EAX-5 (Run 71) metal free extrudate sample of Part A was
post-impregnated as follows:
[0322] 313 g of ammonium molybdate solution adjusted to 5.2-5.4 pH
was mixed with 120 g of nickel nitrate. Water was added to make a
total of 440 cc of solution. The entire solution was transferred
onto 550 g of EAX-5 base. Impregnation was done by incipient
wetness technique in a plastic bag. The impregnated material was
dried overnight at 121.1.degree. C. (250.degree. F.) and calcined
at 537.8.degree. C. (1000.degree. F.) for one hour. The resulting
catalyst is designated EMAX-5 (Run 73) the mercury pore properties
of which are shown at Tables 13A and B.
Comparative Example 6
[0323] Example 24, Part B, was repeated except that the EAX-5
sample was replaced with the extrudate control sample ECAX-2 of Run
72. The resulting metals impregnated extrudate sample is designated
EMCAX-2 (Run 75) the mercury pore properties of which are shown at
Tables 13A and B.
EXAMPLE 25
[0324] Example 22 was repeated except that the blend was composed
of equal amounts of AX-1 and CAX-1 6.8 kg (15 pounds) each. The
blend was mixed with 31 pounds of water in an Eirich mixer,
impregnated with nickel and molybdenum using a metals solution
prepared in accordance with Example 24. Part B, except the total
solution volume was 550 cc due to a higher pore volume of the
present sample.
[0325] The resulting metal impregnated extrudate is designated
EMAX-6 (Run 74), the mercury pore properties of which are shown at
Tables 13A and B.
[0326] The compositional properties, particle diameter, bulk
density, and crush strength for Runs 73 to 75 are summarized at
Table 15.
17TABLE 14 Examples of Metals-Free Base Run No. 70 71 72 Sample ID
EAX-4 EAX-5 ECAX-2 Alumina Type AX-1 AX-1 CAX-1 Catalyst Properties
MoO.sub.3 wt. % Metals-Free NiO wt. % Metals-Free SiO.sub.2 wt. %
0.2 0.2 0.01 Na.sub.2O wt. % 0.41 0.41 0.03 Fe wt. % 0.05 0.05 0.01
Particle Diameter mm 0.99 0.97 1.02 Crush Strength lb/mm 1.96 1.55
1.74
[0327]
18TABLE 15 Post-Impregnation Examples Run No. 73 74 75 Sample ID
EMAX-5 EMAX-6 EMCAX-2 Alumina Type AX-1 AX-1 + CAX-1 CAX-1 Equal
Parts Catalyst Properties MoO.sub.3 wt. % 13.5 13.3 13.3 NiO wt. %
3.5 3.4 3.5 SiO.sub.2 wt. % 0.65 0.24 Na.sub.2O wt. % 0.17 0.11 Fe
wt. % 0.01 0.01 Particle Diameter mm 0.99 0.99 CBD, MaxPack lb/cf
39.6 33.7 36.8 Crush Strength lb/mm 1.64 1.84
EXAMPLE 26
[0328] Vacuum tower bottoms (VTB) derived from arab medium crude
oil having the properties summarized at Table 16 was selected as
the feed to a fixed bed resid hydrotreating pilot plant unit. The
operating conditions of the pilot plant are summarized at Table
17.
[0329] The catalyst from Run 62 (EMAX-1) was placed in the pilot
unit and tested as described below. The pilot unit has four
independent reactors located in a common sandbath. The sandbath
maintains the four reactors at approximately the same temperature.
Each reactor is loaded with 75 cc of the catalyst to be tested.
Inert glass beads are loaded above and below the catalyst bed to
preheat the reactants to the desired conditions and to take up any
additional space. Hydrogen and resid feedstock enter the bottom of
the reactor and flow together up through the catalyst bed and out
the top of the reactor. The products go into a gas liquid
separation vessel which is located downstream of the reactor. The
gas products pass out of the system through a pressure control
valve which is used to control the reactor pressure. The liquid
products pass from the separation vessel through a level control
valve to the liquid product vessel which accumulates the product
until it is removed from the system. The hydrogen flowrate to the
reactor is controlled with a mass flow controller. The resid
feedrate to the reactor is controlled with a feed pump. The
temperature of the reactors are controlled by changing the
temperature of the sandbath.
[0330] The catalyst was tested at reference conditions: LHSV of 1.0
(75 cc/hr feed and 75 cc of catalyst bed volume), reactor
temperature of 426.7.degree. C. (800.degree. F.) and 2000 psig
H.sub.2 pressure. The hydrogen flowrate was maintained at 75 Normal
Liters (NL)/hr (Note: NL is measured at 0.degree. C. and 1
atmosphere pressure). These conditions produce about the same level
of conversion as well as sulfur and Conradson carbon removal as
would be expected for the conventional catalysts in a commercial
ebullating bed hydrocracker. The percent conversion of materials
boiling over 537.8.degree. C. (1000.degree. F.) to materials
boiling under 537.8.degree. C. was measured as a function of time
expressed as barrels of feed processed per pound of
catalystloaded.
[0331] The results are shown at FIG. 23 and designated Run 76.
Comparative Example 7
[0332] Example 26 was repeated except that the catalyst from Run 68
was employed in lieu of that from Run 62.
[0333] The conversion results are also summarized at FIG. 23 as Run
77. As can be seen from FIG. 23, the AX-1 derived sample of Run 76
exhibits a higher activity for cracking the high boiling
(1000+.degree. F.) resid material to lighter products than the
reference CAX-1 derived sample of Run 77. The data shown are
corrected to the standard operating conditions to remove any
fluctuations caused by changes in the actual operating conditions.
The AX-1 derived catalyst of Run 76 also has activity advantages
for saturation (product API increase), desulfurization and
Conradson carbon removal. It is theorized that the higher cracking
and hydro-activity of this catalyst is due to the modified pore
size distribution, and perhaps the chemical composition of base due
to the AX-1 starting materials.
[0334] Sediment and metals removal for Run 76 are slightly inferior
to the control of Run 77. Sediment is expected to increase at
higher resid conversion. The Run 76 sample also has lower porosity
in the macro range, which may also be affecting sediment and metals
performance on this feed.
19TABLE 16 Feedstock Properties Feedstock Arabian Medium Vacuum
Resid ID Number F94-71 F98-559 API @ 60.degree. F. 4.87 5.60 S.G. @
60.degree. F. 1.0376 1.0321 Sulfur wt. % 5.88 4.72 Total Nitrogen.
wt. % 0.41 0.34 Basic Nitrogen, wt. % 0.043 0.12 Conradson Carbon.
wt. % 23.2 26 Pentane Insoluble, wt. % 27.0 22.9 Toluene Insoluble,
wt. % 0.06 0.16 Metals (ppm) Ni 36.8 29.4 V 118.3 103.3 Fe 7 43.9
Zn 2.1 2 Ca 21 7 Na 5.6 21 K 1.4 1.1 Distillation: LV %
>1000.degree. F. 87 97
[0335]
20TABLE 17 Operating Conditions of Pilot Plant Feedstock Arabian
Med VTB Pressure 2000 psig Rx Temp 790-800.degree. F. (near
isothermal) Feedrate 75 cc/hr H.sub.2 Once Thru 75 NL/hr (6000
SCFB) Run Length -3 weeks (about 2.0 bbl/lb) Upflow Regime Catalyst
Loading 75 cc LHSV (Catalyst Basis) Glass Bead Section Provides
reactor space without catalyst Simulates commercial cat/thermal
space ratios
EXAMPLE 27
[0336] Example 24 was repeated except the catalyst from Run 64
(EMAX-2) replaced the catalyst of the reference example and the
feedstock was an alternate Arab medium Vacuum Resid, the properties
for which are summarized at Table 16. The results are grouped as
Run 78 and the conversion performance is summarized at FIG. 24.
EXAMPLE 28
[0337] Example 27 was repeated using the catalyst of Run 66
(EMAX-3) and the results grouped as Run 79 and depicted at FIG.
24.
Comparative Example 8
[0338] Example 27 was repeated using the control catalyst of Run 68
(EMCAX-1). The results are grouped as Run 80 and depicted at FIG.
24.
[0339] As can be seen from FIG. 24, Runs 78 and 79 are superior to
the control in conversion.
[0340] Moreover, in respect to:
[0341] (a) Total Liquid Product API, the control was inferior to
Run 79 but superior to Run 78;
[0342] (b) Sulfur Reduction--the control was inferior to Run 79 but
superior to Run78;
[0343] (c) wt. % Conradson Carbon Residue (CCR) Reduction--the
control was inferior to Run 79 but superior to Run 78;
[0344] (d) Sediment Reduction--the control was superior to Runs 78
and 79, with Run 79 being better than Run 78;
[0345] (e) Vanadium Reduction--the control was superior to Runs 78
and 79, with Run 79 being better than Run 78;
[0346] (f) Nickel Reduction--the control was inferior to Run 79 but
superior to Run 78.
[0347] Note that the CCR is the leftover carbonaceous material
after all of the lighter hydrocarbons are boiled away. It is
measured by a standard destructive distillation test (ASTM (D-189).
The test is run on the feed and on the products. The difference
between the two numbers is the CCR reduction.
[0348] The principles, preferred embodiments, and modes of
operation of the present invention have been described in the
foregoing specification. The invention which is intended to be
protected herein, however, is not to be construed as limited to the
particular forms disclosed, since these are to be regarded as
illustrative rather than restrictive. Variations and changes may be
made bv those skilled in the art, without departing from the spirit
of the invention.
* * * * *