U.S. patent application number 12/671707 was filed with the patent office on 2011-03-10 for integrated fluid catalytic cracking process for obtaining hydrocarbon blends having a high quality as fuel.
This patent application is currently assigned to ENI S.P.A.. Invention is credited to Giovanni Faraci, Alberto Moggi, Paolo Pollesel, Giacomo Rispoli.
Application Number | 20110056870 12/671707 |
Document ID | / |
Family ID | 40299757 |
Filed Date | 2011-03-10 |
United States Patent
Application |
20110056870 |
Kind Code |
A1 |
Rispoli; Giacomo ; et
al. |
March 10, 2011 |
INTEGRATED FLUID CATALYTIC CRACKING PROCESS FOR OBTAINING
HYDROCARBON BLENDS HAVING A HIGH QUALITY AS FUEL
Abstract
The present invention relates to an integrated fluid catalytic
cracking process (FCC) which allows hydrocarbon blends to be
obtained having a high quality as fuel. In particular, it relates
to an integrated process comprising a fluid catalytic cracking step
wherein hydrocarbon cuts of an oil origin are converted into blends
with a high content of light cycle oil (LCO) having a high quality
in terms of density and nature of the aromatic products contained,
which, after a separation and a hydrotreating step, is subjected to
upgrading by treatment with hydrogen and a catalyst comprising one
or more metals selected from Pt, Pd, Ir, Ru, Rh and Re and a
silicoaluminate of an acidic nature.
Inventors: |
Rispoli; Giacomo; (Rome,
IT) ; Moggi; Alberto; (Milan, IT) ; Faraci;
Giovanni; (San Donato Milanese (Milan), IT) ;
Pollesel; Paolo; (San Donato Milanese (Milan), IT) |
Assignee: |
ENI S.P.A.
Rome
IT
|
Family ID: |
40299757 |
Appl. No.: |
12/671707 |
Filed: |
July 21, 2008 |
PCT Filed: |
July 21, 2008 |
PCT NO: |
PCT/EP08/06176 |
371 Date: |
April 20, 2010 |
Current U.S.
Class: |
208/70 ;
208/113 |
Current CPC
Class: |
B01J 35/1038 20130101;
B01J 35/1042 20130101; C10G 45/62 20130101; B01J 29/7869 20130101;
B01J 35/1047 20130101; C10G 69/04 20130101; B01J 21/12 20130101;
C10G 11/05 20130101; B01J 29/7469 20130101; B01J 35/1023 20130101;
B01J 23/40 20130101; B01J 35/1061 20130101 |
Class at
Publication: |
208/70 ;
208/113 |
International
Class: |
C10G 69/10 20060101
C10G069/10; C10G 11/00 20060101 C10G011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 3, 2007 |
IT |
MI2007A 001610 |
Claims
1. An integrated process for the conversion of hydrocarbon cuts of
an oil origin, into hydrocarbon blends having a high quality as
fuel, which comprises the following steps: subjecting the
hydrocarbon cut to fluid catalytic cracking (FCC) to produce Light
Cycle Oil (LCO), subjecting the Light Cycle Oil to hydrotreating,
reacting the hydrotreated Light Cycle Oil obtained in the previous
hydrotreatment step with hydrogen in the presence of a catalytic
system comprising: a) one or more metals selected from Pt, Pd, Ir,
Ru, Rh and Re b) a silicoaluminate of an acidic nature, selected
from a zeolite belonging to the MTW family and a completely
amorphous micro-mesoporous silico-alumina, having a
SiO.sub.2/AL.sub.2O.sub.3 molar ratio ranging from 30 to 500, a
surface area greater than 500 m.sup.2/g, a pore volume ranging from
0.3 to 1.3 ml/g, an average pore diameter smaller than 40
.ANG..
2. The process according to claim 1, comprising the following
steps: 1) subjecting a hydrocarbon cut to fluid catalytic cracking
(FCC) to produce a blend containing LCO, 2) subjecting the blend
resulting from the previous FCC step to separation, in order to
separate at least one LCO fraction and an HCO fraction, 3) possibly
re-feeding at least a part of the HCO fraction to the FCC step; 4)
subjecting the LCO fraction to hydrotreatment; 5) reacting the
product resulting from step (4) with hydrogen in the presence of a
catalytic system comprising: a) one or more metals selected from
Pt, Pd, Ir, Ru, Rh and Re b) a silicoaluminate of an acidic nature
selected from a zeolite belonging to the MTW family and a
completely amorphous micro-mesoporous silico-alumina having an
SiO.sub.2/Al.sub.2O.sub.3 molar ratio ranging from 30 to 500, a
surface area greater than 500 m.sup.2/g, a pore volume ranging from
0.3 to 1.3 ml/g, an average pore diameter smaller than 40
.ANG..
3. The process according to claim 1 or 2, wherein the hydrocarbon
cuts of an oil origin treated in the first step of the integrated
process are gas oil, vacuum gas oil, atmospheric residues, thermal
cracking products and hydro-cracking residues.
4. The process according to claim 1, 2 or 3, wherein the fluid
catalytic cracking step is carried out at a temperature ranging
from 450 to 650.degree. C., a pressure in the reaction area ranging
from 1.3 to 4.5 kg/cm.sup.2 and a catalyst/oil ratio of between 1
and 10 kg/kg, a residence time of the vapours in the reaction area
of between 0.5 and 10 seconds.
5. The process according one or more of the previous claims,
wherein the fluid catalytic cracking step is carried out at a
temperature within the range of 490 to 530.degree. C.
6. The process according to one or more of the claims from 1 to 5,
wherein in the fluid catalytic cracking step the pre-heating
temperature of the feedstock is within the range of 240 to
350.degree. C.
7. The process according to claim 2, wherein the HCO fraction
obtained from the separation is at least partially recycled to the
FCC step.
8. The process according to claim 1 or 2, wherein the
hydrotreatment is carried out in the presence of a catalyst based
on metal compounds of Group VI and/or Group VIII on a carrier.
9. The process according to claim 1 or 2, wherein the
hydrotreatment is carried out at a temperature ranging from 200 to
400.degree. C.
10. The process according to claim 9, wherein the temperature
ranges from 330 to 380.degree. C.
11. The process according to claim 1 or 2, wherein the pressure
ranges from 20 to 100 bar in the hydrotreatment step.
12. The process according to claim 11, wherein the pressure ranges
from 40 to 80 bar.
13. The process according to claim 1 or 2, wherein the component of
an acidic nature (b) is a silico-alumina having an
SiO.sub.2/AL.sub.2O.sub.3 molar ratio ranging from 50 to 300.
14. The process according to claim 1 or 2, wherein the component of
an acidic nature (b) is a silico-alumina having a porosity ranging
from 0.4 to 0.5 ml/g.
15. The process according to claim 1 or 2, wherein the component of
an acidic nature (b) is a microporous silico-alumina having an XRD
spectrum from powders which has no crystalline structure and shows
no peaks.
16. The process according to claim 1 or 2, wherein the metal of
component (a) is selected from platinum, iridium or mixtures
thereof.
17. The process according to claim 1 or 2, wherein the metal, or
the mixture of metals, of component (a) is in a quantity ranging
from 0.1 to 5% by weight with respect to the total weight of the
catalytic composition, wherein the weight percentage of the metal,
or metals, refers to the content of metal expressed as metallic
element.
18. The process according to claim 17, wherein the metal is in a
quantity ranging from 0.3 to 1.5%.
19. The process according to claim 1 or 2, wherein the hydrotreated
light cycle oil is reacted with hydrogen in the presence of the
catalytic system comprising: a) one or more metals selected from
Pt, Pd, Ir, Ru, Rh and Re b) a silico-aluminate of an acidic nature
selected from a zeolite belonging to the MTW family and a
completely amorphous microporous silico-alumina having an
SiO.sub.2/AL.sub.2O.sub.3 molar ratio ranging from 30 to 500, a
surface area greater than 500 m.sup.2/g, a pore volume of between
0.3 and 1.3 ml/g, an average pore diameter smaller than 40 .ANG.,
at a temperature ranging from 240 to 380.degree. C., at a pressure
ranging from 10 to 100 atm, with a WHSV ranging from 0.5 to 5
hr.sup.-1 and a hydrogen and feedstock (H.sub.2/HC) ratio of
between 400 and 2,000 Nlt/kg.
20. The process according to claim 19, wherein the acidic component
(b) is a MTW zeolite, the pressure is higher than 20 atm and lower
than or equal to 80 atm, and the temperature ranges from 250 to
330.degree. C.
21. The process according to claim 19, wherein the acidic component
(b) is a silico-alumina, the pressure is higher than 20 atm and
lower than or equal to 80 atm, the temperature ranges from 300 to
380.degree. C.
22. The process according to claim 1 or 2, wherein the
hydrotreatment is carried out at an LSHV space velocity ranging
from 0.3 to 3 hr.sup.-1.
23. The process according to claim 1 or 2, wherein in the
hydrotreatment step, a H.sub.Z/feedstock ratio ranging from 200 to
2,000 Nl/l, is used.
24. A fluid catalytic cracking (FCC) process for the conversion of
hydrocarbon cuts of an oil origin into blends containing Light
Cycle Oil (LCO), carried out at a temperature ranging from 490 to
530.degree. C.
25. A fluid catalytic cracking (FCC) process for the conversion of
hydrocarbon cuts of an oil origin into blends containing Light
Cycle Oil (LCO), wherein the pre-heating temperature is within the
range of 240 to 350.degree. C.
26. The fluid catalytic cracking (FCC) process according to claim
24 or 25, wherein the pre-heating temperature is within the range
of 240 to 350.degree. C. and the process is carried out at a
temperature ranging from 490 to 530.degree. C.
Description
[0001] The present invention relates to an integrated fluid
catalytic cracking process (FCC) which allows hydrocarbon blends
having a high quality as fuel, to be obtained.
[0002] According to a particular aspect, it relates to an
integrated process comprising a fluid catalytic cracking step
wherein hydrocarbon cuts of an oil origin are converted into blends
having a high content of light cycle oil (LCO) with high quality in
terms of density and nature of the aromatic products contained,
which, after a separation and a hydrotreatment step, is subjected
to an upgrading step by means of treatment with hydrogen and a
catalyst comprising one or more metals selected from Pt, Pd, Ir,
Ru, Rh and Re and a silicoaluminate of an acidic nature.
[0003] Said upgrading step comprises enrichment of the resulting
blend to alkyl benzene compounds, at least partially deriving from
the conversion of naphtho-aromatic structures contained in the LCO
cut, generated during the FCC step and also the hydrotreatment
step.
[0004] The integrated process of the present invention leads to
hydrocarbon blends having a high cetane index and a reduced
density, the latter being of a degree comparable to that which
would be obtained by means of total de-aromatization, but effected
with a much lower hydrogen consumption.
[0005] WO2006/124175 describes a process for the conversion of
hydrocarbon cuts for producing olefins, aromatic and diesel
compounds having a low sulphur content, comprising a fluid
catalytic cracking step for producing olefins and, to a lesser
extent, LCO, a transformation step of the high-boiling portion of
olefins to ethylene and propylene and a hydrocracking step wherein
the LCO cut is mainly trans-formed into aromatic compounds and, to
a lesser extent, to diesel having a low sulphur content.
[0006] WO2007/006473 describes a process for improving the quality
as fuel of hydrotreated hydrocarbon blends which includes putting
said blends in contact with hydrogen in the presence of a catalytic
system comprising one or more metals selected from Pt, Pd, Ir, Ru,
Rh and Re and a silicoaluminate of an acidic nature.
[0007] We have now found an integrated process for the production
of hydrocarbon blends having a high quality as fuel, which
comprises a fluid catalytic cracking (FCC) step to give an LCO
fraction, a hydrotreating step of said LCO fraction and an
upgrading step of the resulting hydrotreated LCO by means of
reaction with hydrogen in the presence of a catalytic system
comprising one or more metals selected from Pt, Pd, Ir, Ru, Rh and
Re and a silicoaluminate of an acidic nature.
[0008] A particularly preferred aspect of the present invention is
to effect the fluid catalytic cracking (FCC) step under such
conditions as to obtain, with a high yield, a better-quality LCO
fraction in terms of density and nature of the aromatic compounds
contained. In particular, in this case, the LCO fraction is
characterized not only by a high quality in terms of density, but
also by a favourable composition in terms of aromatic compounds,
which makes it particularly suitable for being treated in the
subsequent steps of the integrated process of the invention. The
content of polyaromatic compounds is in fact lower with respect to
the LCO cuts obtained under normal FCC conditions, whereas the
content of benzo-naphthene compounds is higher. This preliminary
enrichment in terms of benzo-naphthene compounds makes the
subsequent hydrotreatment and upgrading steps easier, allowing the
production of blends having optimum characteristics as fuel, using
overall amounts of hydrogen lower than what is described in the
known art.
[0009] Furthermore, the blend resulting from the FCC step contains
HCO as major by-product, which can be at least partially recycled
to the FCC step thus allowing an overall higher yield to LCO.
[0010] An object of the present invention therefore relates to an
integrated process for the conversion of hydrocarbon cuts of an oil
origin, into hydrocarbon blends having a high quality as fuel,
which includes the following steps: [0011] subjecting the
hydrocarbon cut to fluid catalytic cracking (FCC) to produce Light
Cycle Oil (LCO), [0012] subjecting the Light Cycle Oil to
hydrotreatment, [0013] reacting the hydrotreated Light Cycle Oil
obtained in the previous hydrotreatment step, with hydrogen in the
presence of a catalytic system comprising: [0014] a) one or more
metals selected from Pt, Pd, Ir, Ru, Rh and Re [0015] b) a
silicoaluminate of an acidic nature, selected from a zeolite
belonging to the MTW family and a completely amorphous
micro-mesoporous silicoalumina, having a molar ratio
SiO.sub.2/AL.sub.2O.sub.3 ranging from 30 to 500, a surface area
greater than 500 m.sup.2/g, a pore volume ranging from 0.3 to 1.3
ml/g, an average diameter of the pores smaller than 40 .ANG..
[0016] According to a particularly preferred aspect, the process of
the present invention is carried out by means of the following
steps:
1) a hydrocarbon cut of an oil origin is subjected to fluid
catalytic cracking (FCC) to produce a blend containing LCO, 2) the
blend resulting from the previous FCC step is subjected to
separation, in order to separate at least one LCO fraction and an
HCO fraction, 3) at least a part of the HCO fraction is possibly
fed again to the FCC step; 4) the LCO fraction is subjected to
hydrotreatment; 5) the product resulting from step (4) is reacted
with hydrogen in the presence of a catalytic system comprising: a)
one or more metals selected from Pt, Pd, Ir, Ru, Rh and Re b) a
silicoaluminate of an acidic nature selected from a zeolite
belonging to the MTW family and a completely amorphous
micro-mesoporous silicoalumina having a molar ratio
SiO.sub.2/Al.sub.2O.sub.3 ranging from 30 to 500, a surface area
greater than 500 m.sup.2/g, a pore volume ranging from 0.3 to 1.3
ml/g, an average pore diameter smaller then 40 .ANG..
[0017] Hydrocarbon cuts suitable for being treated in the first
step of the integrated process of the present invention are, for
example, gas oil, vacuum gas oil, atmospheric residues, products
from thermal cracking and hydrocracking residues.
[0018] The FCC step can be carried out according to the conditions
known to experts in the field, described, for example in Fluid
Catalytic Cracking Handbook 2.sup.nd edition, Reza Sadeghbeigi, ed.
Gulf Professional Publishing, 2000.
[0019] In general, the fluid catalytic cracking process is divided
into two steps, cracking effected in the riser and regeneration of
catalyst carried out in the regenerator, both steps being effected
by means of a catalyst in fluid phase. The catalyst is generally a
compound of silica and alumina in the form of a porous powder
having an average particle-size of 65-85 micron. The cracking
reaction is substantially endothermic, is sustained by the
sensitive heat coming from the regenerated catalyst flow and takes
place by putting the hydrocarbon feedstock in contact with the warm
regenerated catalyst. The reaction conditions include a temperature
ranging from 450 to 650.degree. C., a pressure in the reaction area
ranging from 1.3 to 4.5 kg/cm.sup.2 and a catalyst/oil ratio
ranging from 1 to 10 kg/kg, a residence time of the vapours in the
reaction area ranging from 0.5 to 10 seconds, preferably from 1 to
5 seconds.
[0020] The regeneration of the exhausted cracking catalyst is
effected by combustion with oxygen of the coke deposited on the
catalyst at a temperature ranging from 600 to 815.degree. C. and a
pressure of the regenerator ranging from 1.3 and 4.5 kg/cm.sup.2
and preferably between 2.4 and 4.0 kg/cm.sup.2.
[0021] According to a particularly preferred aspect of the present
invention, the FCC step is carried out under such conditions as to
maximize the formation of LCO and allow an LCO cut to be obtained,
having a high quality from the point of view of density and
characterized by a composition particularly favourable in terms of
aromatic compounds. The content of polyaromatic compounds is in
fact reduced with respect to LCO cuts obtained under normal FCC
conditions, in favour of a higher content of benzo-naphthene
compounds. This composition characteristic facilitates the
subsequent hydrotreatment and upgrading steps, allowing blends
having optimum characteristics as fuel to be obtained, using
overall lower amounts of hydrogen with respect to what is described
in the known art. According to this preferred aspect of the present
patent application, the high LCO yields obtained in the FCC step
are reached by choosing particular and selected temperature
conditions and/or by selecting particular pre-heating temperatures
of the feedstock. The selection of these particular conditions for
effecting the FCC step, also allows the cracking reaction to be
directed towards a higher formation of HCO as reaction by-product,
which, as it can be recycled to the FCC step, allows a higher
overall LCO yield to be obtained.
[0022] The particular and selected temperature conditions which
allow the LCO formation to be maximized, are those ranging from 490
to 530.degree. C.
[0023] The particular pre-heating temperatures of the feed-stock
which allow the LCO yield to be maximized, are within the range of
240 to 350.degree. C.
[0024] In both cases, a pressure ranging from 2.0 to 3.5
kg/cm.sup.2 is preferably used.
[0025] As far as the remaining process parameters are concerned,
the same conditions normally adopted by experts in the field can be
used.
[0026] An LCO yield at least 20% higher, preferably at least 40%
higher, is obtained by carrying out the FCC step so as to satisfy
at least one of the previous temperature and pre-heating
temperature conditions, the remaining complement to 100 consisting
of: [0027] fuel gas (H.sub.2, C1, C2) [0028] LPG (C3-C4) [0029]
gasolines (C5-210.degree. C.) [0030] HCO (370+.degree. C.) [0031]
coke
[0032] The FCC conditions mentioned above for the temperature and
pre-heating temperature of the feedstock, which allow the formation
of LCO to be maximized and obtaining a high-quality LCO cut from
the point of view of density, characterized by a particularly
favourable composition in terms of aromatic compounds, are new and
represent a further aspect of the present invention.
[0033] The blend resulting from the first integrated process step
of the present invention is separated by distillation.
[0034] The HCO fraction obtained by the separation is preferably
recycled to the FCC step, in a blend with the feed-stock, for
example.
[0035] The LCO fraction obtained from the separation, characterized
by a composition, in terms of aromatic compounds, rich in
benzo-naphthene compounds, is subjected to hydrotreatment with the
aim of reducing the nitrogen and sulphur content and varying the
cut composition, further enriching it with benzo-naphthene
compounds.
[0036] The hydrotreatment of the LCO cut is effected in one or more
fixed-bed reactors and the catalytic beds can contain the same or
different catalysts. Catalysts based on metal compounds of Group VI
and/or Group VIII are normally used, on a carrier, preferably an
amorphous carrier, such as, for example, alumina or silico-alumina.
Metals which can be used are, for example, Nickel, Cobalt,
Molybdenum and Tungsten. Examples of catalysts which can be used
and the preparation of the same are described in Hydrocracking
Science and Technology, J. Scherzer and A. J. Gruia, Marcel Dekker,
1996. The hydrotreatment is described, for example, in Catalyst
Science and Technology, Edited by R. Anderson and Boudart, Volume
11, Sprinter-Verlag of 1996. The hydrotreating catalysts are used
in the form of sulphidation products.
[0037] The sulphidation can be obtained, for example, by sending a
suitable feedstock onto the catalyst with the addition of a
sulphidated compound such as dimethyl-disulphide (DMDS),
dimethyl-sulphoxide (DMSO) or other compounds which decompose with
the formation of H.sub.2S.
[0038] The hydrotreatment is preferably effected at a temperature
ranging from 200 to 400.degree. C., even more preferably at a
temperature ranging from 330 to 380.degree. C. The pressure
normally varies from 20 to 100 bar, preferably between 40 and 80
bar. The space velocity (LHSV) preferably ranges from 0.3 to 3
hr.sup.-1. The H.sub.2/feedtosck ratio is preferably between 200
and 2,000 N1/1. During the hydrotreatment, the LCO feedstock
undergoes saturation reactions of the aromatic rings with a
consequent reduction in the aromatic carbon content and enrichment
in naphtho-aromatic compounds.
[0039] The subsequent upgrading step is effected, according to WO
2007/006473, in the presence of a bifunctional catalytic system,
comprising one or more metals selected from Pt, Pd, Ir, Rh, Ru and
Re and a silico-aluminate of an acidic nature selected from a
micro-mesoporous silico-alumina having a suitable composition and a
zeolite belonging to the MTW family.
[0040] This process step leads to a substantial improvement in the
properties of the hydrotreated LCO, in particular in terms of the
cetane index (number), density and distillation curve, which is a
result equivalent to that which can be obtained through the simple
hydrogenation of the aromatic structures. In this step there is a
negligible form ation of low-molecular-weight products and lower
hydrogen consumptions are necessary with respect to the processes
of the known art.
[0041] This step is carried out in the presence of hydrogen, with a
catalytic system including:
[0042] a) one or more metals selected from Pt, Pd, Ir, Ru, Rh and
Re
[0043] b) a silicoaluminate of an acidic nature selected from a
zeolite belonging to the MTW family and a completely amorphous
micro-porous silico-alumina having a SiO.sub.2/Al.sub.2O.sub.3
molar ratio ranging from 30 to 500, a surface area greater than 500
m.sup.2/g, a pore volume ranging from 0.3 to 1.3 ml/g, an average
pore diameter lower than 40 .ANG..
[0044] This step of the process allows a substantial increase in
the cetane index (number) to be obtained, and a decrease in the
density and T95 of the hydrotreated LCO blend. The LCO blend thus
obtained also proves to be further enriched in alkyl-benzene
compounds which at least partially derive from the partially
hydrogenated polycyclic aromatic compounds of the benzo-naphthene
type, both already present in the LCO cut coming from the
particular FCC step of the present integrated process and also
generated during the hydrotreatment.
[0045] The catalysts used in this process step direct the process
towards the formation of alkyl-benzene structures through the
hydro-decyclation of the naphthene ring of naphtho-benzene or
dinaphtho-benzene structures, thus obtaining the best possible
compromise between hydrogen consumption and improvement in the
product properties, at the same time limiting the complete
hydrogenation reaction of the aromatic rings and the cracking
reaction to form light products.
[0046] The catalysts used are those described in patent application
WO2007/006473. The component of an acidic nature (b) of the
catalytic composition used in the present invention can be selected
from zeolites of the MTW type: the MTW family is described in Atlas
of zeolite structure types, W. M. Meier and D. H. Olson, 1987,
Butterworths. The zeolite of the MTW structural type, which can be
effectively used in the present invention, is a silico-alumina with
an SiO.sub.2/Al.sub.2O.sub.3 molar ratio higher than or equal to
20. This zeolite and its preparation are described in A. Katovic
and G. Giordano. Chem. Ind. (Dekker) (Synthesis of Porous
Materials) 1997, 69, 127-137. According to a preferred aspect
ZSM-12 zeolite is used, described in U.S. Pat. No. 3,832,449, and
in Ernst et al., Zeolites, 1987, Vol. 7, September.
[0047] In the preparation of the catalytic composition, the zeolite
is used in its acid form.
[0048] If the component of an acid nature (b) is a silico-alumina,
a preferred aspect is for the SiO.sub.2/Al.sub.2O.sub.3 molar ratio
to range from 50 to 300. According to another preferred aspect, the
silico-alumina has a porosity ranging from 0.4 to 0.5 ml/g.
[0049] Completely amorphous micro-mesoporous silico-aluminas,
useful for the present invention, called MSA, and their preparation
are described in U.S. Pat. No. 5,049,536, EP 659,478, EP 812,804.
Their X-ray spectrum from powders does not show a crystalline
structure or peak. Catalytic compositions useful for the present
invention, wherein the acid component is a silico-alumina of the
MSA type, are described in EP 582,347.
[0050] The silico-aluminas useful for the process of the present
invention can be prepared, in accordance with EP 659,478, starting
from tetra-alkyl ammonium hydroxide, a compound of aluminium which
can be hydrolyzed to Al.sub.2O.sub.3, and a silicon compound which
can be hydrolyzed to SiO.sub.2, wherein said tetra-alkyl ammonium
hydroxide is a tetra(C.sub.2C.sub.5)alkyl ammonium hydroxide, said
compound of aluminium which can be hydrolyzed is an aluminium
tri(C.sub.2C.sub.4)-alkoxide and said silicon compound which can be
hydrolyzed is a tetra C.sub.1C.sub.5)alkyl ortho-silicate: these
reagents are subjected to hydrolysis and gelification, operating at
a temperature equal to or higher than the boiling point, at
atmospheric pressure, of any alcohol which is formed as a
by-product of said hydrolysis reaction, with no elimination, or
with no substantial elimination, of said alcohols from the reaction
environment. The gel produced is dried and calcined, preferably
under an oxidizing atmosphere, at a temperature ranging from 500 to
700.degree. C. for a period of 6-10 hrs.
[0051] An aqueous solution of tetra-alkylammonium hydroxide and
aluminium tri-alkoxide is prepared and tetra-alkylortho silicate is
added to the aqueous solution, operating at a temperature lower
than the hydrolysis temperature, with a quantity of the reagents
which is such as to respect the molar ratios of
SiO.sub.2/AL.sub.2O.sub.3 from 30/1 to 500/1, tetra-alkyl ammonium
hydroxide/SiO.sub.2 from 0.05/1 to 0.2/1 and H.sub.2O/SiO.sub.2
from 5/1 to 40/1, and the hydrolysis and gelation are induced by
heating to a temperature higher than about 65.degree. C. up to
110.degree. C., operating in an autoclave, at autogenous pressure
of the system, or at atmospheric pressure in a reactor equipped
with a condenser.
[0052] As far as the metal component of the catalytic compositions
used in the upgrading step of the present invention is concerned,
this is selected from Pt, Pd, Ir, Ru, Rh and Re and mixtures
thereof. According to a particularly preferred aspect of the
present invention, the metal is platinum, iridium of mixtures
thereof.
[0053] The quantity of metal or mixture of metals preferably ranges
from 0.1 to 5% by weight with respect to the total weight of the
catalytic composition, and preferably from 0.3 to 1.5%.
[0054] The weight percentage of the metal, or metals, refers to the
content of metal(s) expressed as metallic element; in the final
catalyst, after calcination, said metal is in the form of an
oxide.
[0055] Before being used, the catalyst is activated by means of
known techniques, for example by means of a reduction treatment,
preferably by means of drying and subsequent reduction. Drying is
effected under an inert atmosphere at temperatures ranging from 25
to 100.degree. C., whereas the reduction is obtained by thermal
treatment of the catalyst under a reducing atmosphere (H.sub.2) at
temperatures ranging from 300 and 450.degree. C. at a pressure
preferably ranging from 1 to 50 atm.
[0056] The acidic component (b) of the catalyst which is used in
the upgrading step of the process of the present invention, can be
in the form of an extruded product with traditional binders, such
as, for example, aluminium oxide, bohemite, or pseudo-bohemite. The
extruded product can be prepared according to techniques well-known
to experts in the field. The acidic component (b) and the binder
can be pre-mixed in weight ratios of between 30:70 and 90:10,
preferably between 50:50 and 70:30. At the end of the mixing, the
product obtained is consolidated in the desired final form, for
example, in the form of extruded cylinders or tablets.
Alternatively, when component (b) is a silico-alumina, the catalyst
in an extruded form, prepared as described in EP 665055, can be
used as component (b).
[0057] As far as the metal phase (a) of the catalyst is concerned,
this can be introduced by impregnation or ion exchange. According
to the first technique, the component of an acidic nature (b), also
in extruded form, is wetted by means of an aqueous solution of a
metal compound, operating, for example, at room temperature and
with a pH ranging from 1 to 4. The resulting product is dried,
preferably in air, at room temperature, and is calcined under an
oxidizing atmosphere at a temperature ranging from 200 to
600.degree. C.
[0058] In the case of alcohol impregnation, the acidic component
(b) is suspended in an alcohol solution containing the metal. After
impregnation, the solid product is dried and calcined.
[0059] According to the ion exchange technique, the component (b)
is suspended in an aqueous solution of a complex or salt of the
metal, operating at room temperature and at a pH ranging from 6 to
10. After the ion exchange, the solid product is separated, washed
with water, dried and finally thermally treated under an inert or
oxidizing atmosphere. Useful temperatures for the purpose are those
within the range of 200 to 600.degree. C.
[0060] Metal compounds which can be used in the above-mentioned
preparations are: H.sub.2PtCl.sub.6, Pt (NH.sub.3).sub.4(OH).sub.2,
Pt(NH.sub.3).sub.4Cl.sub.2, Pd(NH.sub.3).sub.4(OH).sub.2,
PdCl.sub.2, H.sub.2IrCl.sub.6, RuCl.sub.3, RhCl.sub.3. The
upgrading step of the process of the present invention is
preferably effected at a temperature ranging from 240 to
380.degree. C., at a pressure ranging from 10 to 100 atm, a WHSV
ranging from 0.5 to 5 hrs.sup.-1 and a ratio between hydrogen and
feedstock (H.sub.2/HC) ranging from 400 to 2,000 Nlt/kg. It is
preferable to operate at a pressure higher than 20 atm and lower
than or equal to 80 atm, whereas the temperature is preferably
between 250 and 330.degree. C. if the acidic component (b) is a
zeolite of the MTW type, whereas it preferably ranges from 300 to
380.degree. C. if the acidic component (b) is a silico-alumina.
[0061] The following experimental examples are provided for a
better illustration of the present invention, they are purely
illustrative of particular aspects of the invention and cannot be
considered as limiting its overall scope.
EXAMPLE 1
[0062] A feedstock having the characteristics shown in table 1 is
fed to an FCC pilot plant of the DCR (Davison Circulating Riser)
type, using as catalyst NEKTOR 766 produced by Grace Davison.
[0063] The operational conditions and results of the conversion and
yield are indicated in Table 2, first column (Case 1).
[0064] The same feedstock, with the addition of the recycled
product, was subsequently treated under the conditions indicated in
the second column of Table 2 (Case 2). The relative results are
shown in the same second column. The third column indicates the
results of case 2, expressed as a conversion variation and yield,
wherein said variations were obtained considering the results
obtained for Case 1 as 100%:
TABLE-US-00001 TABLE 1 TBP 5% .degree. C. 253 10% .degree. C. 292
30% .degree. C. 391 50% .degree. C. 442 70% .degree. C. 512 Sulphur
Weight % 0.4 CCR Weight % 2.8 Density 0.889
TABLE-US-00002 TABLE 2 Case 1 Case 2 Case 3 Reaction temperature
.degree. C. 540 520 520 Feedstock pre-heating .degree. C. 230 330
330 temperature Recycled product g/hr 0 300 300 Total feedstock
g/hr 1,000 1,300 1,300 Conversion % w 79.1 71.6 -9 % Dry gas % w
2.7 3.3 22 % LPG % w 19.6 15.1 -23 % Gasoline % w 50.9 47.8 -6 %
LCO % w 10.8 16.4 52 % HCO % w 10.1 12.0 19 % Coke % w 5.9 5.4 -8
%
From Table 2 it can be seen that, by operating under the preferred
conditions of the present invention, in terms of both temperature
and pre-heating temperature, an increase of 52% is obtained in the
yield. The LCO separated by distillation is then fed to the
subsequent hydrotreatment and upgrading steps.
EXAMPLE 2
[0065] A feedstock having the characteristics indicated in Table 3
is fed to an FCC pilot plant of the DCR (Davison Circulating Riser)
type, using NOMUS 215P produced by Grace Davison, as catalyst. The
operational conditions and results relating to the conversion and
yield are shown in table 4, first column (Case 3).
[0066] The same feedstock, with the addition of the recycled
product, was subsequently treated under the conditions indicated in
the second column of Table 4 (Case 4). The results obtained are
shown in the same second column.
[0067] The third column also indicates the results for Case 4
expressed as variations of conversion and yield, wherein said
variations were obtained considering the results obtained for Case
3, as 100%.
TABLE-US-00003 TABLE 3 TBP 5% .degree. C. 273 10% .degree. C. 303
30% .degree. C. 386 50% .degree. C. 430 70% .degree. C. 464 90%
.degree. C. 510 Sulphur Weight % 0.4 CCR Weight % 0.3 Density
0.919
TABLE-US-00004 TABLE 4 Case 3 Case 4 Case 4 Reaction temperature
.degree. C. 540 520 520 Feedstock pre-heating .degree. C. 220 320
320 temperature Recycle g/hr 0 250 250 Total feedstock g/hr 1,000
1,250 1,250 Conversion % w 74.5 67.7 -9 % Dry gas % w 3.2 3.6 13 %
LPG % w 20.3 16.1 -21 % Gasoline % w 45.9 43.5 -5 % LCO % w 16.5
23.8 44 % HCO % w 9.0 8.5 -6 % Coke % w 5.1 4.5 -12 %
[0068] From Table 4 it can be seen that, by operating under the
same preferred conditions of the present invention, in terms of
both temperature and pre-heating temperature, an increase of 44% of
the yield to LCO is obtained. The LCO separated by distillation can
be fed to the subsequent hydrotreatment and upgrading steps.
* * * * *