U.S. patent application number 10/574764 was filed with the patent office on 2007-11-22 for surfactant enhance fluid catalytic cracking process.
This patent application is currently assigned to Exxon Mobil Research and Engineering Company. Invention is credited to W. Russell Adamson, James D. Dearth, Stuart S. Goldstein, George A. Swan III, Ramesh Varadaraj.
Application Number | 20070267323 10/574764 |
Document ID | / |
Family ID | 34467968 |
Filed Date | 2007-11-22 |
United States Patent
Application |
20070267323 |
Kind Code |
A1 |
Varadaraj; Ramesh ; et
al. |
November 22, 2007 |
Surfactant Enhance Fluid Catalytic Cracking Process
Abstract
The atomization of a fluid injected into an atomization zone is
enhanced by providing the fluid with an effective amount of an
additive capable of reducing the static and dynamic interfacial
tension of the fluid components.
Inventors: |
Varadaraj; Ramesh;
(Flemington, NJ) ; Swan III; George A.; (Baton
Rouge, LA) ; Dearth; James D.; (Baton Rouge, LA)
; Goldstein; Stuart S.; (Southampton, GB) ;
Adamson; W. Russell; (Gainesville, VA) |
Correspondence
Address: |
ExxonMobil Research & Engineering Company
P.O. Box 900
1545 Route 22 East
Annandale
NJ
08801-0900
US
|
Assignee: |
Exxon Mobil Research and
Engineering Company
1545 Route 22 East, P.O. BOX 900
Annandale
NJ
08801-0900
|
Family ID: |
34467968 |
Appl. No.: |
10/574764 |
Filed: |
October 1, 2004 |
PCT Filed: |
October 1, 2004 |
PCT NO: |
PCT/US04/32223 |
371 Date: |
April 17, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60510201 |
Oct 10, 2003 |
|
|
|
60604661 |
Aug 25, 2004 |
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Current U.S.
Class: |
208/74 ;
208/81 |
Current CPC
Class: |
C10G 11/18 20130101 |
Class at
Publication: |
208/074 ;
208/081 |
International
Class: |
C10G 11/18 20060101
C10G011/18 |
Claims
1. A surfactant-enhanced atomization process comprising: a) mixing
an effective amount of at least one surfactant with an atomization
fluid to form a first mixture; b) injecting said first mixture into
a fluidized catalytic cracking feedstream to form a second mixture;
and c) conducting said second mixture through a feed nozzle.
2. The process according to claim 1 wherein said effective amount
of surfactant is that amount of surfactant capable of reducing the
static and dynamic interfacial tension between the fluidized
catalytic cracking feedstream and atomizing fluid.
3. The process according to claim 1 wherein said effective amount
of surfactant is about 25 to about 50,000 wppm, based on the
atomization fluid.
4. The process according to claim 2 wherein said at least one
surfactant is selected from those surfactants which, under
fluidized catalytic cracking feed preheating do not decompose, but
will decompose under the effective cracking conditions.
5. The process according to claim 2 wherein said at least one
surfactant is selected from non-ionic surfactants and mixtures
thereof having hydrophilic lipophilic balance values ("HLBs") in
the range of about 3 to about 20.
6. The process according to claim 2 wherein said at least one
surfactant is selected from alkyl alkoxylates.
7. The process according to claim 1 wherein said atomizing fluid is
selected from subcooled water (water having a temperature above its
normal atmospheric pressure boiling point at pressure sufficient to
maintain it in a liquid state), steam, light hydrocarbon gas
(C.sub.4--), inert gases and combinations thereof.
8. The process according to claim 5 wherein the atomizing fluid is
steam.
9. The process according to claim 1 wherein said process further
comprises: a) conducting said second mixture through a feed nozzle
into a fluidized catalytic cracking reaction zone, thereby
producing droplets of the second mixture and injecting them into a
reaction zone; and b) contacting the droplets of the second mixture
with a fluidized catalytic cracking catalyst under effective
catalytic cracking conditions in the reaction zone thereby
producing at least an FCC product stream comprising at least
C.sub.2- dry gas and spent catalyst comprising strippable
hydrocarbons.
10. The process according to claim 9 wherein an effective amount of
said at least one surfactant is that amount sufficient to reduce
the static and dynamic interfacial tension of the fluidized
catalytic cracking feedstream and atomizing fluid such that
droplets of the second mixture formed by conducting the second
mixture through said feed nozzle have a mean droplet diameter less
than about 1000.mu..
11. The process according to claim 9 wherein said effective
cracking conditions include: (i) temperatures from about
500.degree. C. to about 650.degree. C., (ii) hydrocarbon partial
pressures from about 10 to 40 psia (70-280 kPa); and, (iii) a
catalyst to feed (wt/wt) ratio from about 1:1 to 12:1, where the
catalyst weight is based on the total weight of the catalyst
composite.
12. The process according to claim 10 wherein said effective amount
of surfactant is that amount sufficient to reduce the amount of
C.sub.2- dry gas in the FCC product stream.
13. The process according to claim 10 wherein said process further
comprises fractionating said FCC product stream to produce at least
a naphtha boiling range product stream.
14. The process according to claim 1 wherein said fluidized
catalytic cracking feedstream is selected from gas oils, heavy
hydrocarbon oils comprising materials boiling above 1050.degree. F.
(565.degree. C.); heavy and reduced petroleum crude oil; petroleum
atmospheric distillation bottoms; petroleum vacuum distillation
bottoms; pitch, asphalt, bitumen, other heavy hydrocarbon residues;
tar sand oils; shale oil; liquid products derived from coal
liquefaction processes; and mixtures thereof.
15. The process according to claim 1 wherein said effective amount
of surfactant is that amount effective at reducing the static and
dynamic interfacial tension between the FCC feedstream and
atomizing fluid by at least 50%.
16. The process according to claim 13 wherein said effective amount
of surfactant is that amount of surfactant sufficient to reduce the
amount of C.sub.2- dry gas in the FCC product stream.
17. The process according to claim 16 wherein said effective amount
of surfactant is that amount of surfactant sufficient to reduce the
amount of C.sub.2- dry gas in the FCC product stream without
causing foaming in the FCC process unit.
18. The process according to claim 16 wherein said effective amount
of surfactant is that amount of surfactant sufficient to reduce the
amount of C.sub.2- dry gas in the FCC product stream without
causing foaming, haze, or increasing the oxygenate content of said
naphtha boiling range product stream.
19. A surfactant-enhanced fluid catalytic cracking process
comprising: a) mixing an effective amount of a surfactant with an
atomization fluid selected from subcooled water (water having a
temperature above its normal atmospheric pressure boiling point at
pressure sufficient to maintain it in a liquid state), steam, light
hydrocarbon gas (C.sub.4--), inert gases and/or combinations
thereof to form a first mixture; b) injecting said first mixture
into a fluidized catalytic cracking feedstream to form a second
mixture; c) conducting said second mixture through a feed nozzle
into a fluidized catalytic cracking reaction zone, thereby
producing droplets of the second mixture and injecting them into a
reaction zone; and d) contacting the droplets of the second mixture
with a FCC catalyst under effective catalytic cracking conditions
in the reaction zone thereby producing at least an FCC product
stream comprising at least C.sub.2- dry gas and spent catalyst
comprising strippable hydrocarbons; wherein said effective amount
of surfactant is that amount of surfactant capable of reducing the
static and dynamic interfacial tension between the fluidized
catalytic cracking feedstream and the atomizing fluid.
20. The process according to claim 19 wherein said effective amount
of surfactant is about 25 to about 50,000 wppm, based on the
atomization fluid.
21. The process according to claim 20 wherein said at least one
surfactant is selected from those surfactants known which, under
fluidized catalytic cracking feed preheating do not decompose, but
will decompose under the effective cracking conditions.
22. The process according to claim 20 wherein said at least one
surfactant is selected from non-ionic surfactants and mixtures
thereof having hydrophilic lipophilic balance values in the range
of about 3 to about 20.
23. The process according to claim 22 wherein said at least one
surfactant is selected from alkyl alkoxylates, preferably alkyl
ethoxylates, mixtures of aldehydes and ketones, preferably alkyl
aldehyde acids and ketones, more preferably alkyl aromatic
aldehydes and ketones and acids.
24. The process according to claim 19 wherein the atomizing fluid
is steam.
25. The process according to claim 24 wherein an effective amount
of said at least one surfactant is that amount sufficient to reduce
the static and dynamic interfacial tension of the fluidized
catalytic cracking feedstream and atomizing fluid such that
droplets of the second mixture formed by conducting the second
mixture through said feed nozzle have a mean droplet diameter less
than about 1000.mu..
26. The process according to claim 19 wherein said effective
cracking conditions include: (i) temperatures from about
500.degree. C. to about 650.degree. C., (ii) hydrocarbon partial
pressures from about 10 to 40 psia (70-280 kPa); and, (iii) a
catalyst to feed (wt/wt) ratio from about 1:1 to 12:1, where the
catalyst weight is based on the total weight of the catalyst
composite.
27. The process according to claim 24 wherein said effective amount
of surfactant is that amount sufficient to reduce the amount of
C.sub.2- dry gas in the FCC product stream.
28. The process according to claim 19 wherein said process further
comprises fractionating said FCC product stream to produce at least
a naphtha boiling range product stream.
29. The process according to claim 19 wherein said fluidized
catalytic cracking feedstream is selected from gas oils, heavy
hydrocarbon oils comprising materials boiling above 1050.degree. F.
(565.degree. C.); heavy and reduced petroleum crude oil; petroleum
atmospheric distillation bottoms; petroleum vacuum distillation
bottoms; pitch, asphalt, bitumen, other heavy hydrocarbon residues;
tar sand oils; shale oil; liquid products derived from coal
liquefaction processes; and mixtures thereof.
30. The process according to claim 28 wherein said effective amount
of surfactant is that amount of surfactant sufficient to reduce the
amount of C.sub.2- dry gas in the FCC product stream without
causing foaming in the FCC process unit.
31. The process according to claim 28 wherein said effective amount
of surfactant is that amount of surfactant sufficient to reduce the
amount of C.sub.2- dry gas in the FCC product stream without
causing foaming, haze, or increasing the oxygenate content of said
naphtha boiling range product stream.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to the atomization
of fluids. More particularly, the invention is concerned with
enhancing the atomization of fluids, especially fluidized cat
cracker (FCC) feeds, by using a surfactant to alter the interfacial
tension between the fluid and atomizing media.
BACKGROUND OF THE INVENTION
[0002] Atomizing a fluid by passing it through an orifice into a
lower pressure zone to produce a spray of droplets is a technique
used in a wide variety of applications and processes. For example,
in fluidized catalytic cracking (FCC) processes relatively viscous
petroleum feeds are converted into more valuable products including
gasoline, jet fuel, and heating oil. In a FCC process, a preheated
oil feed is mixed with steam and the resulting two-phase fluid is
passed into a lower pressure atomization zone in which the oil is
atomized and brought into contact with a particulate, hot, cracking
catalyst whereby the feed is converted into lower boiling
products.
[0003] The trend in FCC technology has been to use more active
catalysts thereby reducing the length of time the feed needs to be
in contact with the catalyst. To take advantage of a short contact
time, however, the oil needs to be uniformly distributed in the
form of small droplets. Indeed, experience has shown that long oil
vaporization times lead to higher yields of undesirable, low value
products. Additionally, as feeds become heavier the fraction of
steam dispersion gas must be increased to facilitate atomization.
Many FCC units, however, have limited steam capacity, which
constrains their ability to effectively process heavier feeds.
Considerable effort therefore has been devoted to try to find
improved ways for atomizing the oil feed in FCC processes. Examples
of such are found in, for example, U.S. Pat. No. 5,289,976, U.S.
Pat. No. 5,173,175, U.S. Pat. No. 6,093,310 and U.S. Pat. No.
6,352,639 B2.
[0004] Despite the advances made in atomization hardware, and
especially FCC feed injection hardware, it would be an improvement
in the art if a way could be found to enhance oil atomization in
conjunction with hardware and process constraints.
SUMMARY OF THE INVENTION
[0005] The present invention is directed a surfactant-enhanced
atomization process. The process comprises: [0006] a) mixing an
effective amount of at least one surfactant with an atomization
fluid to form a first mixture; [0007] b) injecting said first
mixture into a fluidized catalytic cracking feedstream to form a
second mixture; and [0008] c) conducting said second mixture
through a feed nozzle.
[0009] In another embodiment, the present invention comprises:
[0010] a) mixing an effective amount of at least one surfactant
with an atomization fluid to form a first mixture; [0011] b)
injecting said first mixture into a fluidized catalytic cracking
feedstream to form a second mixture; [0012] c) conducting said
second mixture through a feed nozzle into a fluidized catalytic
cracking reaction zone, thereby producing droplets of the second
mixture and injecting them into the reaction zone; and [0013] d)
contacting the droplets of the second mixture with a FCC catalyst
under effective catalytic cracking conditions in the reaction zone
thereby producing at least an FCC product stream comprising at
least C.sub.2- dry gas and spent catalyst comprising strippable
hydrocarbons.
[0014] In one embodiment of the present invention, the effective
amount of the at least one surfactant is that amount sufficient to
reduce the amount of C.sub.2- dry gas in the FCC product stream,
relative to the amount of C.sub.2- dry gas in the FCC product
stream in the absence of the surfactant.
[0015] In yet another embodiment, the instant invention further
comprises: [0016] a) fractionating said FCC product stream to
produce at least a naphtha boiling range product stream.
[0017] In another embodiment of the present invention, the
effective amount of the at least one surfactant is that amount
sufficient to reduce the amount of C.sub.2- dry gas in the FCC
product stream without causing foaming in the FCC unit.
[0018] In yet another embodiment of the present invention, the
effective amount of the at least one surfactant is that amount
sufficient to reduce the amount of C.sub.2- dry gas in the FCC
product stream without causing foaming, haze, or increasing the
oxygenate content of the naphtha boiling range product.
BRIEF DESCRIPTION OF DRAWINGS
[0019] FIG. 1 is a plot showing the dynamic interfacial tension
(denoted as dynamic IFT) of two different surfactants in water.
[0020] FIGS. 2 and 3 show plots of mean droplet diameter vs. steam
weight % for oil and steam additized with a surfactant (squares)
and oil and steam with no additive (diamonds).
DETAILED DESCRIPTION OF THE INVENTION
[0021] The present invention is directed a surfactant-enhanced
fluid catalytic cracking process. In the practice of the present
invention, an effective amount of at least one surfactant is mixed
with an atomization fluid to form a first mixture. The first
mixture is subsequently injected into a fluidized catalytic
cracking ("FCC") feedstream to form a second mixture, which is
conducted through a feed nozzle. In one embodiment of the present
invention, the invention further comprises conducting the second
mixture through a feed nozzle into a fluidized catalytic cracking
reaction zone, thereby producing droplets of the second mixture and
injecting them into a reaction zone. In the reaction zone, the
droplets of the second mixture are contacted with a FCC catalyst
under effective cracking conditions to produce at least an FCC
product stream and spent catalyst comprising strippable
hydrocarbons.
[0022] As stated above, in practice of the present invention, an
effective amount of at least one surfactant is mixed with an
atomization fluid to form a first mixture. Any surfactant that can
reduce the static and dynamic interfacial tension between an FCC
feedstream and an atomizing fluid may be used. Preferred
surfactants suitable for use in the present invention are any of
those surfactants known to be thermally stable under feed
preheating but will decompose under the effective cracking
conditions used herein. Preferably, the at least one surfactant
does not contain components containing sulfur, nitrogen and metals.
Non-limiting examples of suitable surfactants include non-ionic
surfactants and mixtures thereof having hydrophilic lipophilic
balance values (HLBs) in the range of about 3 to about 20.
Non-limiting examples of such surfactants include alkyl
alkoxylates, preferably alkyl ethoxylates, mixtures of aldehydes
and ketones, preferably alkyl aldehyde acids and ketones, more
preferably alkyl aromatic aldehydes and ketones and acids.
[0023] The atomizing fluid may comprise subcooled water (water
having a temperature above its normal atmospheric pressure boiling
point at pressure sufficient to maintain it in a liquid state),
steam, light hydrocarbon gas (C.sub.4--), inert gases and/or
combinations thereof. Light hydrocarbon gases include, but are not
limited to methane, ethane, ethylene, acetylene, propane,
propylene, propyne, butane and butenes and combinations thereof.
Inert gases as used herein include, but are not limited to, helium,
hydrogen, nitrogen, argon, and other suitable inert gases and
combinations thereof. It is preferred that the atomizing fluid be
steam.
[0024] The first mixture, i.e. the mixture of surfactants and
atomizing fluid, may be prepared either by any one or a combination
of methods. Non-limiting examples of preparing the first mixture
include adding the surfactant to the atomizing fluid, vaporizing
the surfactant and introducing the vaporized surfactant into the
atomizing fluid, and adding the surfactant to water and heating the
surfactant solution to provide a steam and surfactant mixture.
[0025] If steam is the atomization fluid, alkyl alkoxylate type
surfactants are particularly suitable at treat rates in the range
of about 25 ppm to 50,000 ppm based on the weight of steam, and
preferably in the range of 50 to 10,000 ppm. Especially preferred
are alkyl alkyloxylates represented by formulae I to III: ##STR1##
where R is a linear or branched alkyl group of about 3 to 24 carbon
atoms; R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently
alkoxylate groups, (R.sup.5O).sub.mH where R.sup.5 is an alkylene
group of about 2 to 4 carbon atoms and m is from about 1 to 20,
preferably from about 1 to 15, more preferably about 1 to 5, and
more preferably about 1 to 3.
[0026] When surfactants have a formula according to surfactant III
above are used, it is preferred to use it in combination with an
alkyl sorbitan of structure IV. ##STR2##
[0027] For the alkyl sorbitan it is preferred R is an alkyl group
of 3 to 24 carbon atoms. When used in combination with surfactant
III the ratio of surfactant III/IV is preferably between about 95/5
to 30/20 and more preferably about 80/20 to 30/70 and even more
preferably 75/25 to 50/50.
[0028] It should be noted that any surfactants of the type I, II,
III and IV discussed above may be used, alone or in mixtures. It
should also be noted that in some instances, an FCC feedstream
containing a suitable surfactant can also be used. In this
embodiment, when the FCC feedstream is provided with the surfactant
or mixture of surfactants, the amount of surfactant generally is in
the range of 50 to 20,000 ppm based on the weight of the FCC
feedstream, preferably in the range of 50 to 5,000 ppm.
Alternatively, a petroleum oil containing alkyl substituted 1, 2
and 3 ring aromatic compounds may be oxidized to generate a
suitable mixture of oxidized products suitable as additives for the
invention. The oxidization is conducted by heating the oil from
about 150.degree. C. to about 200.degree. C., in the presence of
air for a time sufficient, typically about 4 hours, to produce the
oxidized products suitable as additives for the invention.
Typically such oxidation produces aldehydes, ketones and acids.
[0029] In the practice of the present innovation, the first mixture
is subsequently injected into a fluidized catalytic cracking
feedstream to form a second mixture. The method of injecting the
first mixture into the FCC feedstream is not critical to the
instant invention and can be accomplished by any means known for
injecting an atomizing fluid into a hydrocarbonaceous material.
Non-limiting examples of suitable injection methods include mixing
tees, spargers, and injection devices.
[0030] Any conventional FCC feed can be used in the present
invention. Such feeds typically include heavy hydrocarbonaceous
feeds boiling in the range of about 430.degree. F. to about
1050.degree. F. (220-565.degree. C.), such as gas oils, heavy
hydrocarbon oils comprising materials boiling above 1050.degree. F.
(565.degree. C.); heavy and reduced petroleum crude oil; petroleum
atmospheric distillation bottoms; petroleum vacuum distillation
bottoms; pitch, asphalt, bitumen, other heavy hydrocarbon residues;
tar sand oils; shale oil; liquid products derived from coal
liquefaction processes; and mixtures thereof. The FCC feed may also
comprise recycled hydrocarbons, such as light or heavy cycle
oils.
[0031] As stated above, an effective amount of a surfactant is
mixed with an atomizing fluid to form the first mixture that is
injected into the FCC feedstream. As used herein, an effective
amount of a surfactant is to be considered that amount of
surfactant capable of reducing the static and dynamic interfacial
tension between the FCC feedstream and atomizing fluid. In a
preferred embodiment, an effective amount of surfactant is about 25
to about 50,000 wppm, based on the atomization fluid, more
preferably about 25 to about 10,000, most preferably about 25 to
about 5,000. Reducing the interfacial tension results in a narrow
distribution of small droplets of the second mixture when it is
conducted through the feed nozzle. Small droplet sizes increases
the vaporization rate of the second mixture and provides better
contacting with catalysts. For example, a 25% reduction in the mean
oil droplet diameter boosts vaporization rate by 35% to 50%, and
shorter vaporization times typically improve the yield of desirable
products. Thus, it is preferred that an effective amount of
surfactant be that amount effective at reducing the static and
dynamic interfacial tension between the FCC feedstream and
atomizing fluid by at least 50%. Preferably, an effective amount of
surfactant or mixture of surfactants will be that amount sufficient
to reduce the static and dynamic interfacial tension between the
FCC feedstream and atomizing fluid such that the droplets formed by
conducting the second mixture through a feed nozzle have a mean
droplet diameter less than about 1000.mu., preferably less than
500.mu..
[0032] In one embodiment of the present invention, the
above-described second mixture is conducted through a feed nozzle
into a fluidized catalytic cracking reaction zone. The droplets of
the second mixture, having the above-described droplet size, are
contacted with a FCC catalyst under effective catalytic cracking
conditions in the reaction zone. In this embodiment, any FCC
cracking catalyst can be used. Effective cracking conditions
include: (i) temperatures from about 500.degree. C. to about
650.degree. C., preferably from about 525.degree. C. to 600.degree.
C.; (ii) hydrocarbon partial pressures from about 10 to 40 psia
(70-280 kPa), preferably from about 20 to 35 psia (140-245 kPa);
and, (iii) a catalyst to feed (wt/wt) ratio from about 1:1 to 12:1,
preferably from about 4:1 to 10:1, where the catalyst weight is the
total weight of the catalyst composite. The contacting of the
second mixture and the FCC catalyst produces at least an FCC
product stream comprising at least C.sub.2- dry gas and spent
catalyst comprising strippable hydrocarbons. It should be noted
that C.sub.2- dry gas as used herein is meant to refer to the
gasses produced by the FCC cracking reaction that have a chemical
makeup and boiling point range of C.sub.2 and below, i.e. methane,
ethane, H.sub.2, C.sub.2.dbd. such as ethylene, etc. Thermal
cracking produces increased amounts of dry gas while effective
catalytic cracking produces less C.sub.2- dry gas than thermal
cracking. An efficient FCC produces lower amounts of C.sub.2- dry
gas by promoting increased catalytic cracking and decreased thermal
cracking. Thus, the efficiency of the present process is noted by a
reduction in C.sub.2- dry gas in the FCC product stream. In this
embodiment, an effective amount of surfactant is further to be
considered an amount of surfactant sufficient to reduce the amount
of C.sub.2- dry gas in the FCC product stream.
[0033] As discussed above, another embodiment of the instant
invention involves fractionating the FCC product stream to produce
at least a naphtha boiling range product stream. As used herein, a
naphtha boiling range product is meant to refer to hydrocarbon
streams boiling in the range of about 50.degree. F. (10.degree. C.)
to about 450.degree. F. (232.degree. C.). The method by which the
FCC product stream is fractionated is not critical to the instant
invention, and any type of fractionation known can be used. For
example, atmospheric or vacuum distillation may be employed in
fractionating the FCC product stream. In this embodiment an
effective amount of surfactant is further defined as that amount of
surfactant sufficient to reduce the amount of C.sub.2- dry gas in
the FCC product stream without causing foaming, haze, or increasing
the oxygenate content of said naphtha boiling range product stream.
Controlling the haze, etc. of the naphtha boiling range product
stream is important because it is typically used as a blending
component for motor gasolines. It should be noted that haze is
typically a result of water entrapment in the naphtha boiling range
product.
[0034] Also, as discussed above, another embodiment of the instant
invention an effective amount of surfactant is further defined as
that amount of surfactant sufficient to reduce the amount of
C.sub.2- dry gas in the FCC product stream without causing foaming
in the FCC process unit.
[0035] The above description is directed to several embodiments of
the present invention. Those skilled in the art will recognize that
other embodiments that are equally effective could be devised for
carrying out the spirit of this invention.
[0036] The following examples will illustrate the improved
effectiveness of the present invention, but are not meant to limit
the present invention in any fashion.
EXAMPLES
[0037] The effectiveness of using a surfactant in the atomization
fluid of a Fluidized Catalytic Cracking ("FCC") unit was tested in
a nominal 20 kB/D unit. For a period of five days, a surfactant was
added in various treat rates under a combination of conditions and
with a variety of feeds in order to determine the effect the
surfactant would have on the FCC process. The Examples below
represent the five days that the surfactant was added to the
atomization steam of the FCC.
Example 1
[0038] Neodol 91-2.5E, a primary alcohol ethoxylate surfactant
commercially available from Shell Chemicals was added to
atomization steam in an amount of 1000 wppm, based on the
atomization steam mass flow rate. This surfactant-enhanced
atomization steam was used to atomize an FCC feed whose properties
are listed below: TABLE-US-00001 Gravity, API 19.1 Carbon, wt %
84.7 Hydrogen, wt % 11.57 Nitrogen, wppm 1504 Sulfur, wt % 2.964
5%/50%/95% BP (wt) 516/798/990.degree. F.
[0039] The injection of additized steam continued for a period of 2
to 3 hours. During this test period the FCC unit was operated under
constant conditions including an oil feed rate of 16.9 kbbl/day,
3.7 klb/hr atomization steam, riser outlet temperature of
1005.degree. F., and a catalyst to oil weight ratio of 9.5 lbs.
catalyst/lb. of oil.
[0040] During the test run, FCC dry gas samples obtained from the
FCC unit were analyzed by gas chromatography, and light cat naphtha
("LCN") having a nominal boiling point range of C.sub.5-320.degree.
F. was collected and analyzed for foaming, haze, and oxygenate
content by ASTM D-4815 and confirmed by GC/MS analysis. These
analyses showed low ppm levels of alcohols and ketones at the
detection limit and virtually the same in LCN samples before and
after surfactant addition. The foaming test was conducted by
vigorously shaking about 100 ml of the LCN in a 150 ml tube for 3
minutes. The agitated LCN was allowed to stand for 1 minute and the
initial foam height and time of foam collapse (foam stability) were
determined. Base line samples with no surfactant and samples
obtained during surfactant addition showed no difference in foam
height or foam stability. The LCN was analyzed for haze by visual
examination of the sample. Base line samples with no surfactant and
samples obtained during surfactant addition showed no difference in
haze. A sample of the FCC feed (containing the surfactant-enhanced
atomization fluid) was also analyzed by for interfacial tension.
About a 5% reduction in each hydrogen, ethane, and ethylene in dry
gas samples was observed during the surfactant addition period.
Example 2
[0041] The same Neodol 91-2.5E primary alcohol ethoxylate
surfactant used in Example 1 was added to atomization steam in an
amount of 2000 wppm, based on the steam mass flow rate. This
surfactant-enhanced atomization fluid was used to atomize a FCC
feed with the following properties: TABLE-US-00002 Gravity, API
19.0 Carbon, wt % 86.41 Hydrogen, wt % 11.73 Nitrogen, wppm 1510
Sulfur, wt % 2.92 5%/50%/95% BP (wt) 513/796/991.degree. F.
[0042] The injection of additized steam continued for a period of 2
to 3 hours. During this period, the FCC unit was operated under
constant conditions including an oil feed rate of 16.9 kbbl/day of
feed, 3.7 klb/hr atomization steam, riser outlet temperature of
990.degree. F., and a catalyst to oil weight ratio of 9.5 lbs.
catalyst/lb. of oil.
[0043] During the test run, FCC dry gas samples obtained from the
FCC unit were analyzed by gas chromatography, and light cat naphtha
("LCN") having a nominal boiling point range of C.sub.5-320.degree.
F. was collected and analyzed for foaming, haze, and oxygenate
content. The foaming, oxygenate content, and haze were determined
according to the methods outlined in Example 1 above. A Sample of
the FCC feed (containing the surfactant-enhanced atomization fluid)
was also analyzed for interfacial tension. About 5% reduction in
each methane, ethane, and ethylene in dry gas samples was observed
during the surfactant addition period.
Example 3
[0044] The same Neodol 91-2.5E primary alcohol ethoxylate
surfactant used in Example 1 was added to atomization steam in an
amount of 5000 wppm, based on the steam mass flow rate. This
surfactant-enhanced atomization fluid was used to atomize an FCC
feed with the following properties: TABLE-US-00003 Gravity, API
18.7 Carbon, wt % 85.1 Hydrogen, wt % 11.67 Nitrogen, wppm 1663
Sulfur, wt % 2.979 5%/50%/95% BP (wt) 511/804/1003.degree. F.
[0045] The injection of additized steam continued for a period of 2
to 3 hours. During this test period, the FCC unit was operated
under constant conditions including an oil feed rate of 16.9
kbbl/day of feed, 3.7 klb/hr atomization steam, riser outlet
temperature of 990.degree. F., and a catalyst to oil weight ratio
of 9.5 lbs. catalyst/lb. of oil.
[0046] During the test run, FCC dry gas samples obtained from the
FCC unit were analyzed by gas chromatography, and light cat naphtha
("LCN") having a nominal boiling point range of C.sub.5-320.degree.
F. was collected and analyzed for foaming, haze, and oxygenate
content. The foaming, oxygenate content, and haze were determined
according to the methods outlined in Example 1 above. A Sample of
the FCC feed (containing the surfactant-enhanced atomization fluid)
was also analyzed for interfacial tension. About 5% reduction in
each hydrogen, ethane, ethylene, propane, and propylene was
observed during the surfactant addition period.
Example 4
[0047] Span 80, Tween-80, Brij-35, Brij-58 and Brij-700 surfactants
were used to additize water. Span, Tween and Brij are trademarks of
ICI Americas, Inc. The chemical structure of the Brij, Tween and
Span surfactants is the same as formula II, III and IV respectively
as previously given.
[0048] The air/water equilibrium interfacial tension of a 0.1 wt %
solution of the surfactants in water was determined for each
surfactant by the Wilhelmy plate method at 25.degree. C. The
corresponding air/water equilibrium interfacial tensions are shown
in Table 1. A substantial reduction in interfacial tension (from 72
dyne/cm for untreated water) was achieved. TABLE-US-00004 TABLE 1
IFT (dyne/cm) R m HLB (+/-1) BRIJ 35 C12 23 16.7 31 52 C16 20 15 42
700 C18 100 18.8 49 TWEEN 80 C18 R.sub.1 + R.sub.2 + R.sub.3 +
R.sub.4 = 15 41 --(CH.sub.2--CH.sub.2O).sub.20--H Span 80 C18
Interface: Air/Water
[0049] The dynamic interfacial tension of Tween 80 in Brij 58 in
water was determined by the differential bubble pressure method and
the results are shown in FIG. 1. Within two seconds the equilibrium
interfacial tension is reached for both surfactants.
Example 5
[0050] Neodol 91-2.5E, a surfactant which is a trademark of Shell
Chemicals was used to additize water. The chemical structures of
the surfactant is shown below:
R--O--(CH.sub.2--CH.sub.2--O).sub.m--H Neodol: R=linear
C.sub.9H.sub.19, m=2
[0051] The FCC feed oil/water interfacial tension at 2000 ppm treat
rate of Neodol in water was determined by the pendant drop method
at 176.degree. F. (80.degree. C.)) (Table 2). At least 70%
reduction in interfacial tension was observed for the Neodol
additive. TABLE-US-00005 TABLE 2 Feed IFT {+/-1} (dynes/cm) FCC
Feed Oil/Water 20 FCC Feed Oil/1000 ppm Neodol 91-2 in water 6
Example 6
[0052] Two distilled water samples, one containing 1000 ppm of
Neodol 91-2.5E and the other 1000 ppm of Exxal DDA-3 were prepared.
Exxal DDA-3 is a trademark of ExxonMobil Chemicals with formula I
where n=3 and R is branched C.sub.12H.sub.25 group. The samples
were heated to 212.degree. F. (100.degree. C.) with vigorous mixing
to produce steam. Steam was collected and condensed in a receiving
vessel. Surface tension was measured on the distilled water
containing 1000 ppm surfactant and on the condensed water in the
receiving vessel. Surface tension of water was 72 dynes/cm. Values
of surface tension lower than 72 dynes/cm indicate the presence of
surfactants in water. Identical surface tensions for the distilled
water containing 2000 ppm surfactant and for the condensed water in
the receiving vessel indicate that the surfactants vaporize with
steam. The results are shown in Table 3. TABLE-US-00006 TABLE 3
Feed IFT {+/-0.5} (dynes/cm) Water 72 1000 ppm Neodol in water 25.6
Condensed water in receiving vessel 26.8 100 ppm Exxal DDA-3 in
water 25.6 Condensed water in receiving vessel 27.6
Example 7
[0053] FCC feed atomization experiments were conducted to determine
the influence of oil additization and steam additization on droplet
size. In the case of oil additization, the oil was additized with a
Tween 80/Span 80 mixture in the ratio of 60/40 at a treat rate of
2000 ppm based on the weight of oil. The oil with additive was
preheated to 150.degree. F. (66.degree. C.). The preheated oil was
passed through a calibrated rotameter at 3 g/sec, and further
heated to 450.degree. F. (232.degree. C.). Superheated steam at
450.degree. F. (232.degree. C.) was produced using a flash
vaporization heater. The water inlet to the flash vaporization
heater was monitored using a rotameter.
[0054] The superheated steam and oil was mixed in a T-junction, and
passed through a feed injector, 120 mm long and 1.4 mm in diameter.
The pressure and temperature of the oil and steam mixture were
monitored at the T-junction using a thermocouple and a pressure
gauge. The oil and steam mixture was sprayed horizontally into an
exhaust system, which separated the oil from the steam.
[0055] A Malvern particle diameter analyzer was positioned 3 inches
from the exit of the feed injector. Drop sizes were obtained at
each operating condition for three separate runs. Good
repeatability between the runs was observed. The flow rate was
maintained within .+-.2% during the duration of data collection.
The temperature was also maintained within .+-.2.degree. C. during
the same period. FIG. 2 shows the results, namely a reduction in
droplet size.
[0056] In the case of steam additization, Neodal 91-2.5E was added
to water at a treat rate to produce 2000 ppm of Neodol based on the
weight of steam, the water heated to produce a mixture of steam and
additive and the mixture was then mixed with the oil in a
T-junction. Thereafter the procedure as with oil additization was
followed.
[0057] The effect of the Neodol steam additive on the Sauter Mean
Diameter (SMD) (SMD=diameter of liquid oil droplet with the same
volume/surface ratio as the entire spray) of drop sizes is shown in
FIG. 3. A 5-10% reduction in oil droplet SMD was obtained with
Neodal additization of steam.
Example 8
[0058] 200 g of a crude oil from western Canada was placed in a
three-necked glass flask and heated to a temperature of 150.degree.
C. to 180.degree. C. for 4 hours with a continuous purge of air at
80 to 100 scf/bbl/hour. After completion of reaction the product
was tapped hot from the reactor. The product was added to n-decane
at various concentrations and mixed. Equilibrium oil/water
interfacial tension was determined using the pendant drop described
in the art. Results are shown in Table 4. TABLE-US-00007 TABLE 4
Interfacial Tension Wt % AO Product dynes/cm None 56 0.1 22 1 25 10
30
For all concentrations of product added to n-decane, a substantial
decrease in interfacial tension was observed, which is forecast to
correspondingly improve atomization of the liquid hydrocarbon.
* * * * *