U.S. patent application number 10/025050 was filed with the patent office on 2003-06-19 for desulfurization of middle distillates.
Invention is credited to Johnson, Byron G., Johnson, Marvin M., Owen, Steven A., Slater, Peter N., Sughrue, Edward L. II.
Application Number | 20030111389 10/025050 |
Document ID | / |
Family ID | 21823772 |
Filed Date | 2003-06-19 |
United States Patent
Application |
20030111389 |
Kind Code |
A1 |
Johnson, Marvin M. ; et
al. |
June 19, 2003 |
Desulfurization of middle distillates
Abstract
A process for desulfurizing middle distillates by charging a
sulfur-containing middle distillate and a hydrogen-containing
diluent to a reaction zone in respective amounts and under reaction
conditions sufficient to vaporize substantially all of the
sulfur-containing middle distillate present in the reaction zone.
In the reaction zone, the vaporized middle distillate is contacted
with a sorbent comprising a promoter metal and zinc oxide to
thereby provide a desulfurized middle distillate comprising less
sulfur than the sulfur-containing middle distillate initially
charged to the reaction zone.
Inventors: |
Johnson, Marvin M.;
(Bartlesville, OK) ; Sughrue, Edward L. II;
(Bartlesville, OK) ; Owen, Steven A.; (Kingood,
TX) ; Slater, Peter N.; (Bartlesville, OK) ;
Johnson, Byron G.; (Bartlesville, OK) |
Correspondence
Address: |
RICHMOND, HITCHCOOK, FISH & DOLLAR
P.O. Box 2443
Bartlesville
OK
74005
US
|
Family ID: |
21823772 |
Appl. No.: |
10/025050 |
Filed: |
December 19, 2001 |
Current U.S.
Class: |
208/208R ;
208/209; 208/213; 208/246; 208/247; 208/249; 208/299 |
Current CPC
Class: |
C10G 25/003 20130101;
C10G 45/02 20130101 |
Class at
Publication: |
208/208.00R ;
208/209; 208/213; 208/246; 208/247; 208/249; 208/299 |
International
Class: |
C10G 045/02 |
Claims
What is claimed is:
1. A hydrocarbon desulfurization process comprising the steps of:
(a) co-feeding a sulfur-containing middle distillate and a
hydrogen-containing diluent to a reaction zone in respective
amounts and under reaction conditions sufficient to vaporize
substantially all of said sulfur-containing middle distillate
present in said reaction zone; and (b) contacting the vaporized
middle distillate with a sorbent comprising a promoter metal and
zinc oxide in said reaction zone to thereby provide a desulfurized
middle distillate comprising less than about 50 weight percent of
the amount of sulfur in said sulfur-containing middle
distillate.
2. A process according to claim 1, wherein said hydrogen-containing
diluent enters said reaction zone at a rate in a range of from
about 1,000 to about 10,000 SCFB.
3. A process according to claim 2, wherein said sulfur-containing
middle distillate boils in a range of from about 300 to about
750.degree. F., has a mid-boiling point of more than about
350.degree. F., and comprises more than about 50 ppmw sulfur.
4. A process according to claim 3, wherein said desulfurized middle
distillate comprises less than about 50 ppmw sulfur.
5. A process according to claim 4, wherein said reaction conditions
in said reaction zone includes a temperature in a range of from
about 650 to about 850.degree. F. and a pressure in a range of from
about 250 to about 600 psig, and wherein said sulfur-containing
middle distillate enters said reaction zone at a rate in a range of
from about 0.5 to about 10 LHSV.
6. A process according to claim 5, wherein said sorbent further
comprises an aluminate and said promoter metal is selected from the
group consisting of nickel, cobalt, iron, manganese, tungsten,
silver, gold, copper, platinum, zinc, tin, ruthenium, molybdenum,
antimony, vanadium, iridium, chromium, palladium, oxides thereof,
precursors to oxides thereof, and combinations thereof.
7. A process according to claim 1, wherein said hydrogen-containing
diluent comprises more than about 25 volume percent hydrogen and
said hydrogen-containing diluent enters said reaction zone at a
rate of from about 2,000 to about 8,000 SCFB.
8. A process according to claim 7, wherein said sulfur-containing
middle distillate boils in a range of from 350 to 725.degree. F.,
has a mid-boiling point of more than about 400.degree. F., and
comprises from about 100 to about 50,000 ppmw sulfur.
9. A process according to claim 8, wherein said desulfurized middle
distillate comprises less than about 30 ppmw sulfur.
10. A process according to claim 9, wherein said reaction
conditions in said reaction zone include a temperature in a range
of from about 700 to about 800.degree. F. and a pressure in a range
of from about 450 to about 550 psig, and said sulfur-containing
middle distillate enters said reaction zone at a rate of from about
1.0 to about 5 LHSV.
11. A process according to claim 10, wherein said sorbent further
comprises zinc aluminate and said promoter metal is a
reduced-valence promoter metal having a valence which is at least
one valence number lower than the valence of said promoter metal in
its common oxidized state.
12. A process according to claim 11, wherein said promoter metal
comprises a metal selected from the group consisting of nickel,
nickel oxide, nickel oxide precursors, and combinations
thereof.
13. A process according to claim 1, wherein said
hydrogen-containing diluent comprises at least about 75 volume
percent hydrogen, and said hydrogen-containing diluent enters said
reaction zone at a rate in a range of from about 4,000 to about
6,000 SCFB.
14. A process according to claim 1, wherein at least about 75
weight percent of said sulfur-containing middle distillate present
in said reaction zone is present in the vapor phase.
15. A process according to claim 1, wherein said reaction zone is a
reaction zone of a fluidized bed reactor.
16. A hydrocarbon desulfurization process comprising the steps of:
(a) charging a sulfur-containing middle distillate to a reaction
zone; (b) simultaneously with step (a), charging a
hydrogen-containing diluent to said reaction zone in an amount
sufficient to vaporize substantially all of said sulfur-containing
middle distillate present in said reaction zone; and (c) contacting
said sulfur-containing middle distillate with a sorbent comprising
a promoter metal and zinc oxide in said reaction zone under
reaction conditions sufficient to convert at least a portion of
said zinc oxide to zinc sulfide using sulfur removed from said
sulfur-containing middle distillate, thereby providing a
desulfurized middle distillate and a sulfurized sorbent.
17. A process according to claim 16, wherein at least about 95
weight percent of said sulfur-containing middle distillate present
in said reaction zone is present in the vapor phase.
18. A process according to claim 17, wherein said promoter metal is
selected from the group consisting of nickel, cobalt, iron,
manganese, tungsten, silver, gold, copper, platinum, zinc, tin,
ruthenium, molybdenum, antimony, vanadium, iridium, chromium,
palladium, oxides thereof, precursors to oxides thereof, and
combinations thereof.
19. A process according to claim 18, wherein said sorbent further
comprises an aluminate.
20. A process according to claim 19, wherein said sulfur-containing
middle distillate boils in a range of from about 300 to about
700.degree. F., has a mid-boiling point of more than about
350.degree. F., and comprises more than about 50 ppmw sulfur.
21. A process according to claim 20, wherein said reaction
conditions in said reaction zone includes a temperature in a range
of from about 650 to about 850.degree. F. and a pressure in a range
of from about 250 to about 600 psig, and said sulfur-containing
middle distillate enters said reaction zone at a rate in a range of
from about 0.5 to about 10 LHSV.
22. A process according to claim 21, wherein said
hydrogen-containing diluent enters said reaction zone at a rate in
a range of from about 1,000 to about 10,000 SCFB.
23. A process according to claim 22, wherein said
hydrogen-containing diluent comprises at least about 25 volume
percent hydrogen, and said hydrogen-containing diluent enters said
reaction zone at a rate in a range of from about 2,000 to about
8,000 SCFB.
24. A process according to claim 16, wherein at least 98 weight
percent of said sulfur-containing middle distillate present in said
reaction zone is present in the vapor phase.
25. A process according to claim 24, wherein said sulfur-containing
middle distillate comprises diesel fuel boiling in a range of from
about 375 to 700.degree. F., has a mid-boiling point of more than
500.degree. F., has an API gravity in a range of from 30 to 38, has
a minimum flash point of at least 100.degree. F., and comprises
from about 100 to about 50,000 ppmw sulfur.
26. A process according to claim 25, wherein said reaction
conditions in said reaction zone include a temperature in a range
of from about 700 to about 800.degree. F. and a pressure in a range
of from about 450 to about 550 psig, and said sulfur-containing
middle distillate enters said reaction zone at a rate in a range of
from about 1.0 to about 5 LHSV.
27. A process according to claim 26, wherein said
hydrogen-containing diluent comprises at least 95 volume percent
hydrogen.
28. A process according to claim 27, wherein said
hydrogen-containing diluent enters said reaction zone at a rate in
a range of from about 4,000 to about 6,000 SCFB.
29. A hydrocarbon desulfurization process comprising the steps of:
(a) charging a sulfur-containing middle distillate comprising at
least about 50 ppmw sulfur to a reaction zone at a rate in a range
of from about 0.5 to about 10 LHSV, said reaction zone maintained
at a temperature in a range of from about 650 to about 850.degree.
F. and a pressure in a range of about 250 to about 600 psig; (b)
simultaneously with step (a), charging hydrogen to said reaction
zone at a rate in a range of from about 2,000 to about 8,000 SCFB
to thereby vaporize at least about 95 weight percent of said
sulfur-containing middle distillate present in said reaction zone;
and (c) contacting said sulfur-containing middle distillate with a
sorbent comprising reduced-valence nickel and zinc oxide in said
reaction zone to thereby produce a desulfurized middle distillate
comprising less than about 50 ppmw sulfur.
30. A process according to claim 29, wherein said sulfur-containing
middle distillate consists essentially of diesel fuel boiling in a
range of from 375 to 700.degree. F., having a mid-boiling point of
more than 500.degree. F., having a API gravity in a range of from
30 to 38, having a minimum flash point of at least 100.degree. F.,
and comprising from about 100 to about 50,000 ppmw sulfur.
31. A process according to claim 29, wherein said reaction
conditions in said reaction zone includes a temperature in a range
of from about 700 to about 800.degree. F. and a pressure in a range
of from about 450 to about 550 psig, and said sulfur-containing
middle distillate enters said reaction zone at a rate in a range of
from about 1.0 to about 5 LHSV.
32. A process according to claim 29, wherein said sorbent further
comprises zinc aluminate, and said sorbent comprises said
reduced-valence nickel in an amount in a range of from about 0.5 to
about 50 weight percent.
33. A process according to claim 32, wherein said reduced-valence
nickel is present in said sorbent composition in an amount in a
range of from about 4 to about 40 weight percent, and said
reduced-valence nickel has a valence of less than 2.
34. A process according to claim 33, wherein said reduced-valence
nickel has a valence of zero.
35. A hydrocarbon desulfurization process comprising the steps of:
(a) charging a sulfur-containing middle distillate to a reaction
zone of a fluidized bed reactor; (b) simultaneously with step (a),
charging a hydrogen-containing diluent to said reaction zone in an
amount sufficient to cause vaporization of at least about 75 weight
percent of said sulfur-containing middle distillate present in said
reaction zone; (c) contacting said sulfur-containing middle
distillate with a sorbent comprising a promoter metal and zinc
oxide in said reaction zone to thereby provide a desulfurized
middle distillate comprising less than 50 ppmw sulfur and a
sulfurized sorbent comprising zinc sulfide; (d) separating said
desulfurized middle distillate and said sulfurized sorbent; (e)
contacting at least a portion of said sulfurized sorbent with an
oxygen-containing stream in a regeneration zone under regeneration
conditions sufficient to convert at least a portion of said zinc
sulfide to zinc oxide, thereby providing a regenerated sorbent; (f)
contacting at least a portion of said regenerated sorbent with a
reducing stream in an activation zone under activation conditions
sufficient to reduce the valence of at least a portion of said
promoter metal, thereby providing an activated sorbent; and (g)
returning at least a portion of said activated sorbent to said
reaction zone.
36. A process according to claim 35, wherein said
hydrogen-containing diluent enters said reaction zone at a rate in
a range of from about 1,000 to about 10,000 SCFB.
37. A process according to claim 36, wherein said sulfur-containing
middle distillate boils in a range of from about 300 to about
750.degree. F. and has a mid-boiling point of more than about
350.degree. F.
38. A process according to claim 37, wherein said reaction
conditions in said reaction zone includes a temperature in a range
of from about 650 to about 850.degree. F. and a pressure in a range
of from about 250 to about 600 psig, and said sulfur-containing
middle distillate enters said reaction zone at a rate of from about
0.5 to about 10 LHSV.
39. A process according to claim 38, wherein said promoter metal is
selected from the group consisting of nickel, cobalt, iron,
manganese, tungsten, silver, gold, copper, platinum, zinc, tin,
ruthenium, molybdenum, antimony, vanadium, iridium, chromium,
palladium, oxides thereof, precursors to oxides thereof, and
combinations thereof.
40. A process according to claim 39, wherein said sorbent further
comprises an aluminate.
41. A process according to claim 40, wherein said reaction zone,
said regeneration zone, and said activation zone are located in
separate vessels.
42. A process according to claim 35, wherein said
hydrogen-containing diluent comprises at least 95 volume percent
hydrogen, and said hydrogen-containing diluent enters said reaction
zone at a rate in a range of from about 4,000 to about 6,000
SCFB.
43. A process according to claim 42, wherein said sulfur-containing
middle distillate consists essentially of diesel fuel boiling in a
range of from 375 to 700.degree. F., having a mid-boiling point of
more than 500.degree. F., having API gravity in a range of from 30
to 38, having a minimum flash point of at least 100.degree. F., and
comprising from about 100 to about 50,000 ppmw sulfur.
44. A process according to claim 43, wherein at least 95 weight
percent of said sulfur-containing middle distillate present in said
reaction zone is present in the vapor phase.
45. A process according to claim 44, wherein said sorbent further
comprises zinc aluminate.
46. A process according to claim 45, wherein at least 10 weight
percent of said promoter metal is present in the form of a
reduced-valence promoter metal, and said reduced-valence promoter
metal has a valence which is at least one valence number lower than
the valence of said promoter metal in its common oxidized
state.
47. A process according to claim 46, wherein said promoter metal is
selected from the group consisting of nickel, nickel oxide, nickel
oxide precursors, and combinations thereof.
48. A process according to claim 47, wherein said reduced-valence
promoter metal has a valence of zero.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to an improved sorption
process for removing sulfur from middle distillates.
[0002] Middle distillates, such as diesel fuel, jet fuel, and
kerosene, typically contain a quantity of sulfur. It is well known
that high levels of sulfur in such middle distillates can cause
pollution when the middle distillates are combusted. High levels of
sulfur compounds in automotive fuels, such as diesel fuel, are
undesirable because oxides of sulfur present in automotive exhaust
may irreversibly poison noble metal catalysts employed in
automobile catalytic converters. Emissions from such poisoned
catalytic converters may contain high levels of non-combusted
hydrocarbons, oxides of nitrogen, and/or carbon monoxide which,
when catalyzed by sunlight, form ground level ozone, more commonly
referred to as smog. Thus, there exists a need to reduce the sulfur
content in middle distillates.
[0003] One problem encountered in conventional processes for
desulfurizing middle distillates is the inability to vaporize the
middle distillate under suitable desulfurization reaction
conditions. Vaporization of the middle distillate during
desulfurization is desirable because it allows for more efficient
mass transfer of the middle distillate in the desulfurization
reaction zone. However, for conventional desulfurization processes,
the positive impact of middle distillate vaporization in the
reaction zone is outweighed by the negative impact of the reaction
conditions (e.g., high temperature and/or high diluent flow rate)
required to vaporize the middle distillate.
[0004] Recently, a unique process for removing sulfur from
hydrocarbons using a sorbent composition which is both fluidizable
and circulatable has been developed (see, U.S. Pat. Nos. 6,254,766
and 6,274,031, the disclosures of which are incorporated herein by
reference). In this new type of desulfurization process, it is
highly advantageous for substantially all of the hydrocarbon
present in the fluidized bed reactor (where the hydrocarbon is
contacted with the sorbent) to be vaporized because the presence of
liquids in such a fluidized bed reactor causes significant
inefficiencies.
[0005] When the hydrocarbon feed to the fluidized bed reactor
comprises hydrocarbons having low boiling points, such as
catalytically cracked gasoline, the low boiling point hydrocarbon
vaporizes easily at the standard operating conditions for the
fluidized bed reactor. However, when a higher-boiling point
hydrocarbon feed, such as a middle distillate, is charged to the
fluidized bed reactor, the middle distillate does not fully
vaporize in the reactor under standard reaction conditions. Thus,
there exists a need for a middle distillate desulfurization process
in which substantially all of the middle distillate in the
desulfurization reaction zone is maintained in the vapor phase and
the reaction conditions sufficient to achieve such vaporization do
not reduce the efficiency of the desulfurization process to an
unacceptable level.
SUMMARY OF THE INVENTION
[0006] It is thus an object of the present invention to provide an
improved process for desulfurizing middle distillates such as
diesel fuel.
[0007] Another object of the present invention is to provide a
process for desulfurizing middle distillates in which substantially
all of the middle distillates in the desulfurization reaction zone
are present in the vapor phase.
[0008] A further object of the present invention is to provide a
middle distillate desulfurization process in which the
desulfurization reaction conditions are sufficient to maintain
substantially all of the middle distillate in the vapor phase,
while still providing a high level of sulfur removal.
[0009] It should be noted that the above-listed objects need not
all be accomplished by the invention claimed herein and other
objects and advantages of the invention will be apparent from the
following description of the invention and the appended claims.
[0010] In one aspect of the present invention, a hydrocarbon
desulfurization process is provided. The process comprises the
steps of: (a) co-feeding a sulfur-containing middle distillate and
a hydrogen-containing diluent to a reaction zone in respective
amounts and under reaction conditions sufficient to vaporize
substantially all of the sulfur-containing middle distillate
present in the reaction zone; and (b) contacting the vaporized
middle distillate with a sorbent comprising a promoter metal and
zinc oxide in the reaction zone to thereby provide a desulfurized
middle distillate comprising less than about 50 weight percent of
the amount of sulfur in the sulfur-containing middle
distillate.
[0011] In accordance with another aspect of the present invention,
there is provided a hydrocarbon desulfurization process comprising
the steps of: (a) charging a sulfur-containing middle distillate to
a reaction zone; (b) simultaneously with step (a), charging a
hydrogen-containing diluent to the reaction zone in an amount
sufficient to vaporize substantially all of the sulfur-containing
middle distillate present in the reaction zone; and (c) contacting
the sulfur-containing middle distillate with a sorbent comprising a
promoter metal and zinc oxide in the reaction zone under reaction
conditions sufficient to convert at least a portion of the zinc
oxide to zinc sulfide using sulfur removed from the
sulfur-containing middle distillate, thereby providing a
desulfurized middle distillate and a sulfurized sorbent.
[0012] In accordance with a further aspect of the present
invention, there is provided a desulfurization process comprising
the steps of: (a) charging a sulfur-containing middle distillate
comprising at least about 50 ppmw sulfur to a reaction zone at a
rate in a range of from about 0.5 to about 10 LHSV, said reaction
zone maintained at a temperature in a range of from about 650 to
about 850.degree. F. and a pressure in a range of from about 250 to
about 600 psig; (b) simultaneously with step (a), charging hydrogen
to the reaction zone at a rate in a range of from about 2,000 to
about 8,000 SCFB to thereby vaporize at least about 95 weight
percent of the sulfur-containing middle distillate present in the
reaction zone; and (c) contacting the sulfur-containing middle
distillate with a sorbent comprising reduced-valence nickel and
zinc oxide in the reaction zone to thereby produce a desulfurized
middle distillate comprising less than about 50 ppmw sulfur.
[0013] In accordance with a still further aspect of the present
invention, there is provided a middle distillate desulfurization
process comprising the steps of: (a) charging a sulfur-containing
middle distillate to a reaction zone of a fluidized bed reactor;
(b) simultaneously with step (a), charging a hydrogen-containing
diluent to the reaction zone at a rate sufficient to cause
vaporization of at least about 75 weight percent of the
sulfur-containing middle distillate present in the reaction zone;
(c) contacting the sulfur-containing middle distillate with a
sorbent comprising a promoter metal and zinc oxide in the reaction
zone to thereby provide a desulfurized middle distillate comprising
less than 50 ppmw sulfur and a sulfurized sorbent comprising zinc
sulfide; (d) separating the desulfurized middle distillate and the
sulfurized sorbent; (e) contacting at least a portion of the
sulfurized sorbent with an oxygen-containing stream in a
regeneration zone under regeneration conditions sufficient to
convert at least a portion of the zinc sulfide to zinc oxide,
thereby providing a regenerated sorbent; (f) contacting at least a
portion of the regenerated sorbent with a reducing stream in an
activation zone under activation conditions sufficient to reduce
the valence of at least a portion of the promoter metal, thereby
producing an activated sorbent; and (g) returning at least a
portion of the activated sorbent to the reaction zone.
BRIEF DESCRIPTION OF THE DRAWING
[0014] FIG. 1 is a graph showing the effect of varying the hydrogen
flow rate in a diesel desulfurization process.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] In accordance with one embodiment of the present invention,
a novel process is provided for desulfurizing a middle distillate
by contacting the vaporized middle distillate with a sorbent
comprising a promoter metal and zinc oxide.
[0016] The middle distillate feed employed in the process of the
present invention is preferably a mixture of hydrocarbons having a
boiling range (ASTM D86-00) of from about 300.degree. F. to about
750.degree. F., more preferably from about 350.degree. F. to about
725.degree. F. The middle distillate feed preferably has a
mid-boiling point (ASTM D86-00) of more than about 350.degree. F.,
more preferably more than about 400.degree. F., and still more
preferably more than about 450.degree. F. The middle distillate
feed preferably has an API gravity (ASTM D287-92) in a range of
from about 20 to about 50, more preferably from about 25 to about
45. The middle distillate feed preferably has a minimum flash point
(ASTM D93-99) of at least about 80.degree. F., more preferably at
least about 90.degree. F. Examples of suitable middle distillates
include, but are not limited to, diesel fuel, jet fuel, kerosene,
light cycle oil, and the like, and mixtures thereof.
[0017] Most preferably, the middle distillate feed employed in the
desulfurization process of the present invention consists
essentially of diesel fuel boiling in a range of from 375.degree.
F. to 700.degree. F., having a mid-boiling point of more than
500.degree. F., having an API gravity in a range of from 30 to 38,
and having a minimum flash point above 100.degree. F.
[0018] The middle distillate described herein as a suitable feed in
the desulfurization process of the present invention may comprise a
quantity of aromatics, olefins, and sulfur, as well as paraffins
and napthenes. The amount of aromatics in the middle distillate is
preferably in a range of from about 10 to about 90 weight percent
aromatics based on the total weight of the middle distillate, more
preferably from about 20 to about 80 weight percent aromatics. The
amount of olefins in the middle distillate is preferably less than
about 10 weight percent olefins based on the total weight of the
middle distillate, more preferably less than about 5 weight percent
olefins, and most preferably less than 2 weight percent olefins.
The amount of atomic sulfur in the middle distillate is generally
greater than about 50 parts per million by weight (ppmw) atomic
sulfur, more preferably in a range of from about 100 ppmw to about
50,000 ppmw atomic sulfur, and most preferably from 150 ppmw to
2,000 ppmw prior to treatment of the middle distillate fluid with
the process of the present invention. It is preferred for at least
about 50 weight percent of the atomic sulfur present in the
sulfur-containing middle distillate employed in the present
invention to be in the form of organosulfur compounds. More
preferably, at least about 75 weight percent of the atomic sulfur
present in the sulfur-containing middle distillate is in the form
of organosulfur compounds, and most preferably at least 90 weight
percent of the atomic sulfur is in the form of organosulfur
compounds. As used herein, "sulfur" used in conjunction with "ppmw
sulfur" or the term "atomic sulfur", denotes the amount of atomic
sulfur (about 32 atomic mass units) in the sulfur-containing fluid,
not the atomic mass, or weight, of a sulfur compound, such as an
organo-sulfur compound.
[0019] As used herein, the term "sulfur" denotes any sulfur
compounds normally present in a middle distillate stream, such as
diesel fuel. Examples of sulfur compounds which can be removed from
a middle distillate stream through the practice of the present
invention include, but are not limited to, hydrogen sulfide,
carbonyl sulfide (COS), carbon disulfide (CS.sub.2), mercaptans
(RSH), organic sulfides (R--S--R), organic disulfides (R--S--S--R),
thiophenes, substituted thiophenes, organic trisulfides, organic
tetrasulfides, benzothiophene, benzothiophenes, alkyl thiophenes,
dibenzothiophene, alkyl benzothiophenes, alkyl dibenzothiophenes,
and the like, and mixtures thereof as well as heavier molecular
weights of the same which are normally present in middle
distillates of the types contemplated for use in the
desulfurization process of the present invention, wherein each R
can be an alkyl, cycloalkyl, or aryl group containing 1 to 10
carbon atoms.
[0020] As used herein, the term "fluid" denotes gas, liquid, vapor
and combinations thereof.
[0021] As used herein, the term "vaporized" or "vapor" denotes the
state in which the sulfur-containing middle distillate, such as
diesel fuel, is primarily in a gas or vapor phase.
[0022] The sorbent composition with which the middle distillate is
contacted in order to desulfurize the middle distillate generally
comprises a promoter metal and zinc oxide. The sorbent composition
employed in the present invention can be prepared in accordance
with the sorbent preparation method disclosed in U.S. Pat. Nos.
6,274,533, 6,254,766, and 6,184,176 the disclosures of which are
incorporated herein by reference.
[0023] As used herein with reference to the sorbent composition,
the term "metal" denotes metal in any form such as elemental metal,
metal oxide, or a metal oxide precursor. The promoter metal of the
sorbent composition is preferably selected from the group
consisting of nickel, cobalt, iron, manganese, tungsten, silver,
gold, copper, platinum, zinc, tin, ruthenium, molybdenum, antimony,
vanadium, iridium, chromium, palladium, ruthenium, oxides thereof,
precursors to oxides thereof, and combinations thereof. Most
preferably, the promoter metal is selected from the group
consisting of nickel, nickel oxide, nickel oxide precursors, and
combinations thereof. The promoter metal will generally be present
in the sorbent composition of the present invention in an amount in
a range of from about 1 to about 60 weight percent promoter metal
based on the total weight of the sorbent composition, preferably an
amount in a range of from about 5 to about 50 weight percent
promoter metal, and most preferably in an amount in a range of from
10 to 40 weight percent promoter metal for best sulfur removal.
[0024] Usually, the promoter metal in the common oxidation state of
the promoter metal is combined with the zinc oxide portion of the
sorbent composition. Alternatively, the promoter metal, or even the
entire sorbent composition, can be oxidized after sulfur removal to
bring the promoter metal back to the common oxidized state. Prior
to use as a sorbent, the number of oxygen atoms associated with the
promoter metal must be reduced to form a reduced-valence promoter
metal. Consequently, prior to sulfur removal, at least a portion of
the promoter metal present in the sorbent composition must be
present as a reduced-valence promoter metal. While not wishing to
be bound by theory, it is believed that this reduced-valence
promoter metal can chemisorb, cleave, or remove sulfur. Thus,
either the number of oxygen atoms associated with the promoter
metal is reduced or the oxidation state of the promoter metal is a
zero-valent metal. For example, if nickel is the promoter metal,
nickel oxide (NiO) can be used and the reduced-valence nickel
(promoter metal) can be either nickel metal (Ni.sup.0) or a
non-stoichiometric nickel oxide having a formula of NiO.sub.(1-x)
wherein 0<x<1. If tungsten is the promoter metal, tungsten
oxide (WO.sub.3) can be used and the reduced-valence tungsten
(promoter metal) can be either tungsten oxide (WO.sub.2), tungsten
metal (W.sup.0), or a non-stoichiometric tungsten oxide having a
formula of WO.sub.(3-y) wherein 0<y<3.
[0025] Of the total quantity of the promoter metal present in the
sorbent composition, it is preferred that at least about 10 weight
percent of the promoter metal to be present in the form of a
reduced-valence promoter metal, i.e., either a zero-valent metal or
a non-stoichiometric metal oxide, as described above. More
preferably at least about 40 weight percent of the promoter metal
is a reduced-valence promoter metal, and most preferably at least
80 weight percent of the promoter metal is a reduced-valence
promoter metal for best sorbent activity and sulfur removal. The
reduced-valence promoter metal will generally be present in the
sorbent composition of the present invention in an amount in a
range of from about 0.5 to about 50 weight percent reduced-valence
promoter metal based on the total weight of the sorbent
composition, preferably in an amount in a range of from about 4 to
about 40 weight percent reduced-valence promoter metal, and most
preferably in an amount in a range of from 8 to 35 weight percent
reduced-valence promoter metal for best sorbent activity and sulfur
removal.
[0026] The zinc oxide component of the sorbent composition employed
in the desulfurization process of the present invention can be in
the form of zinc oxide, such as a dispersion of small crystallites
of, or powdered, zinc oxide, or in the form of one or more zinc
compounds that are convertible to zinc oxide. Examples of suitable
zinc compounds that are convertible to zinc oxide include, but are
not limited to, zinc sulfide, zinc sulfate, zinc hydroxide, zinc
carbonate, zinc acetate, zinc nitrate, and combinations thereof.
Preferably, the zinc oxide is present in the form of small
crystallites of zinc oxide for best sorbent activity and sulfur
removal. Zinc oxide will generally be present in the sorbent
composition of the present invention in an amount in a range of
from about 10 to about 90 weight percent zinc oxide based on the
total weight of the sorbent composition, preferably in an amount in
a range of from about 15 to about 60 weight percent zinc oxide, and
most preferably in an amount in a range of from 20 to 55 weight
percent zinc oxide for best sorbent activity and sulfur
removal.
[0027] When the sorbent composition is exposed to high temperatures
(e.g., during calcination), it is preferred for at least a portion
of the zinc oxide and the promoter metal to form a substitutional
solid solution having the general formula: M.sub.XZn.sub.YO,
wherein M is the promoter metal, X is a numerical value in a range
of from about 0.5 to about 0.99, and Y is a numerical value in a
range of from about 0.01 to about 0.5. Such substitutional solid
solution will generally be present in an amount in a range of from
about 5 to about 60 percent by weight of the sorbent composition,
most preferably from 20 to 40 weight percent. When the sorbent
composition comprising the substitutional solid solution is reduced
(i.e., activated), it is preferred for at least a portion of the
substitutional solid solution to be converted to a reduced metal
solid solution having the general formula: M.sub.AZn.sub.B, wherein
M is the promoter metal, A is a numerical value in a range of from
about 0.7 to about 0.99, and B is a numerical value in a range of
from about 0.01 to about 0.3. Such reduced metal solution will
generally be present in an amount in a range of from about 5 to
about 70 percent by weight of the sorbent composition, most
preferably from 25 to 45 weight percent.
[0028] Preferably, the sorbent composition employed in the
inventive desulfurization process further comprises a refractory
metal oxide such as, for example, silica, alumina, silica-alumina,
aluminate, and/or silica-aluminate. The refractory metal oxide such
as, for example, silica, alumina, silica-alumina, aluminate, and/or
silica-aluminate can enhance the porosity of the resulting
composition such that the active sites of the sorbent can be
exposed to the reacting mixture.
[0029] Any suitable source of silica may be employed in the sorbent
composition such as, for example, diatomite, expanded perlite,
silicalite, silicate, silica colloid, flame-hydrolyzed silica,
silica gel, precipitated silica, and the like, and combinations
thereof. In addition, silicon compounds that are convertible to
silica such as silicic acid, ammonium silicate, and the like, and
combinations thereof can also be employed. Preferably, the silica
source is diatomite or expanded perlite for best sorbent activity
and sulfur removal. When the sorbent comprises silica, the silica
will generally be present in the sorbent composition in an amount
in a range of from about 5 to about 85 weight percent silica based
on the total weight of the sorbent composition, preferably in an
amount in a range of from about 10 to about 60 weight percent
silica, and most preferably in an amount in a range of from 15 to
55 weight percent silica for best sorbent activity and sulfur
removal. Generally, perlite comprises silicon dioxide, aluminum
oxide, potassium oxide, sodium oxide, calcium oxide, plus trace
elements.
[0030] The alumina employed in the preparation of the sorbent
composition can be any suitable commercially available alumina
material such as, for example, colloidal alumina solutions,
hydrated aluminas, peptized aluminas and, generally, those alumina
compounds produced by the dehydration of alumina hydrates. The
preferred alumina is a hydrated alumina such as, for example,
boehmite or pseudoboehmite for best sorbent activity and sulfur
removal. When the sorbent comprises alumina, the alumina will
generally be present in the sorbent composition in an amount in a
range of from about 1 to about 30 weight percent alumina based on
the total weight of the sorbent composition, preferably in an
amount in a range of from about 5 to about 20 weight percent
alumina, and most preferably in an amount in a range of from 8 to
15 weight percent alumina for best sorbent activity and sulfur
removal. When the sorbent composition is exposed to high
temperatures (e.g., during calcination) at least a portion,
preferably a substantial portion of the alumina is converted to an
aluminate, most preferably a zinc aluminate and/or a nickel-zinc
aluminate. Preferably, the sorbent composition comprises from about
2 to about 30 weight percent nickel-zinc aluminate, most preferably
from 8 to 25 weight percent nickel-zinc aluminate.
[0031] The sorbent composition can additionally comprise a binder.
The binder can be any suitable compound that has cement-like, or
adhesion, properties which can help to bind the components of the
sorbent composition together. Suitable examples of binders include,
but are not limited to, cements such as, for example, gypsum
plaster, common lime, hydraulic lime, natural cements, portland
cements, and high alumina cements, and the like, and combinations
thereof. A particularly preferred binder is calcium aluminate. When
a binder is present, the amount of binder in the sorbent
composition is generally in a range of from about 0.1 to about 50
weight percent binder based on the total weight of the sorbent
composition. Preferably, the amount of the binder in the sorbent
composition is in a range of from about 1 to about 40 weight
percent, and most preferably in a range of from 5 to 30 weight
percent for best binding results.
[0032] The sorbent composition employed in the inventive
desulfurization process preferably is in the form of a particulate,
most preferably a microsphere, having a mean particle size in a
range of from about 1 micrometer (micron) to about 500 micrometers,
more preferably in a range of from about 10 micrometers to about
300 micrometers for best sulfur removal. As used herein, the term
"mean particle size" refers to the size of the particulate material
comprising the sorbent as determined by using a RO-TAP Testing
Sieve/Shaker, manufactured by W.S. Tyler, Inc. of Mentor, Ohio, or
other comparable sieves. To determine mean particle size, the
material to be measured is placed in the top of a nest of standard
8 inch diameter stainless steel framed sieves with a pan on the
bottom. The material undergoes sifting for a period of about 10
minutes; thereafter, the material retained on each sieve is
weighed. The percent retained on each sieve is calculated by
dividing the weight of the material retained on a particular sieve
by the weight of the original sample. This information is used to
compute the mean particle size, by the method outlined in Chapter 3
of Fluidization Engineering by Kunii and Levenspiel (1987).
[0033] The middle distillate desulfurization process of the present
invention is carried out in the reaction zone of a reactor under a
set of reaction conditions that include total pressure,
temperature, liquid hourly space velocity, and diluent flow rate.
In the desulfurization process of the present invention, it is
preferred that the reaction conditions be sufficient such that the
middle distillate, preferably diesel fuel, is maintained in a vapor
phase in the reaction zone.
[0034] The reaction conditions at which the reaction zone is
maintained preferably include a temperature in a range of from
about 650.degree. F. to about 850.degree. F., more preferably from
about 700.degree. F. to about 800.degree. F., still more preferably
from about 720.degree. F. to about 780.degree. F., and most
preferably from 740.degree. F. to 760.degree. F. for best sulfur
removal.
[0035] The total pressure at which the reaction zone is maintained
is preferably in a range of from about 250 pounds per square inch
gauge (psig) to about 600 psig, more preferably from about 350 psig
to about 575 psig, still more preferably from about 450 psig to
about 550 psig, and most preferably from 475 psig to 525 psig for
best sulfur removal.
[0036] As used herein, "liquid hourly space velocity" or "LHSV" is
defined as the numerical ratio of the rate at which the middle
distillate fluid is charged to the reaction zone in barrels per
hour at standard conditions of temperature and pressure (STP)
divided by the barrels of sorbent composition contained in the
reaction zone to which the middle distillate is charged. In the
practice of the present invention, such LHSV should be in a range
of from about 0.5 hr.sup.-1 to about 10 hr.sup.-1, more preferably
from about 1.0 hr.sup.-1 to about 5 hr.sup.-1, still more
preferably from about 1.5 HR.sup.-1 to about 4.0 hr.sup.-1, most
preferably from 1.8 hr.sup.-1 to 3.0 hr.sup.-1 for best sulfur
removal.
[0037] An important aspect of the present invention is the
employing of a hydrogen-containing diluent as a means for providing
improved vaporization of the middle distillate in the reaction
zone. The hydrogen-containing diluent employed in the process of
the present invention preferably contains at least about 25 volume
percent hydrogen based on the total volume of the
hydrogen-containing diluent, more preferably at least about 50
volume percent hydrogen, still more preferably at least about 75
volume percent hydrogen, and most preferably more than 95 volume
percent hydrogen. The rate at which the hydrogen-containing diluent
is charged to the reaction zone is preferably in a range of from
about 1,000 standard cubic feet per barrel (SCFB) of the middle
distillate fluid to about 10,000 SCFB, more preferably from about
2,000 SCFB to about 8,000 SCFB, still more preferably from about
4,000 SCFB to about 6,000 SCFB, and most preferably from 4,500 SCFB
to 5,500 SCFB. It is presently preferred for the middle distillate
and hydrogen-containing diluent to be simultaneously introduced
into the reaction zone via a common inlet port(s). Most preferably,
the middle distillate and hydrogen-containing diluent are combined
prior to introduction into the reaction zone, and are thereafter
co-fed into the reaction zone.
[0038] Preferably, the reaction conditions employed in the
desulfurized process of the present invention are sufficient to
provide vaporization of substantially all of the middle distillate
present in the reaction zone. Preferably, at least about 75 weight
percent of the middle distillate present in the reaction zone is in
the vapor phase, more preferably at least about 95 weight percent
of the middle distillate is in the vapor phase, and most preferably
at least 98 weight percent of the middle distillate is in the vapor
phase.
[0039] It is preferred that the desulfurization reaction of the
present invention be carried out in the reaction zone of a
fluidized bed reactor. As used herein, the term "fluidized bed
reactor" denotes a reactor wherein a fluid feed, as defined
earlier, can be contacted with solid particles (such as sorbent
particles) in a manner such that the solid particles are at least
partly suspended within the reaction zone by the flow of the fluid
feed through the reaction zone and the solid particles are
substantially free to move about within the reaction zone as driven
by the flow of the fluid feed through the reaction zone. Although
it is preferred for the present invention to be carried out in a
fluidized bed reactor, advantages, such as improved mass transfer
and reduced pore filling, are also realized when the inventive
desulfurization process is carried out in a fixed bed reactor.
[0040] When the sorbent composition is contacted with the vaporized
middle distillate in the reaction zone, sulfur compounds,
particularly organosulfur compounds, present in the middle
distillate are removed from the middle distillate. The sulfur
removed from the middle distillate is employed to convert at least
a portion of the zinc oxide of the sorbent composition into zinc
sulfide. While not wishing to be bound by theory, the inventors
postulate that the promoter metal of the sorbent composition
functions to facilitate removal of the sulfur from the middle
distillate while the zinc oxide functions to facilitate the storage
of the sulfur on/in the sorbent composition through the conversion
of at least a portion of the zinc oxide to zinc sulfide.
[0041] After sulfur removal in the reaction zone, the fluids in the
reaction zone (i.e., the hydrogen-containing diluent and the
desulfurized middle distillate) and the solids in the reaction zone
(i.e., the sulfurized sorbent composition) can then be separated by
any manner or method known in the art for separating a solid from a
fluid, preferably a solid from a gas. Examples of suitable
separating means for separating solids from gasses include, but are
not limited to, cyclonic devices, settling chambers, impingement
devices, filters, and combinations thereof.
[0042] In contrast to many conventional sulfur removal processes
(e.g., hydrodesulfurization), it is preferred that substantially
none of the sulfur removed from the middle distillate is converted
into hydrogen sulfide. Rather, it is preferred for the fluid
effluent (primarily comprising the desulfurized middle distillate
and the hydrogen-containing diluent) from the reaction zone to
comprise not more than about 200 percent (by weight) of the amount
of hydrogen sulfide in the fluid feed (primarily comprising the
sulfur-containing middle distillate and the hydrogen-containing
diluent) charged to the reactor, more preferably not more than
about 150 weight percent of the amount of hydrogen sulfide in the
fluid feed, and most preferably less hydrogen sulfide than the
fluid feed. It is preferred for the fluid effluent to comprise less
than about 50 weight percent of the amount of sulfur in the
sulfur-containing middle distillate initially charged to the
reaction zone, more preferably less than about 20 weight percent of
the amount of sulfur in the fluid feed, and most preferably less
than 10 weight percent of the sulfur in the fluid feed. It is
preferred for the total sulfur content of the fluid effluent to be
less than about 50 parts per million by weight (ppmw) of the total
fluid effluent, more preferably less than about 30 ppmw, still more
preferably less than about 15 ppmw, and most preferably less than
10 ppmw.
[0043] The desulfurized middle distillate, preferably desulfurized
diesel fuel, can thereafter be recovered from the fluid effluent
and preferably liquified. Liquification of such desulfurized middle
distillate fluid can be accomplished by any method or manner known
in the art. The liquified, desulfurized middle distillate
preferably comprises at least about 50 weight percent less sulfur
than the sulfur-containing middle distillate initially charged to
the reaction zone, more preferably at least about 80 weight percent
less sulfur, and most preferably at least 90 weight percent less
sulfur. The liquified, desulfurized middle distillate preferably
comprises less than about 50 ppmw sulfur, more preferably less than
about 30 ppmw sulfur, still more preferably less than about 15 ppmw
sulfur, and most preferably less than 10 ppmw sulfur.
[0044] After separation of the sulfurized sorbent from the fluid
effluent of the reactor, the sulfurized sorbent composition can be
regenerated in a regeneration zone by contacting the sulfurized
sorbent composition with an oxygen-containing stream under suitable
regeneration conditions. The regeneration is preferably carried out
at a temperature in a range of from about 100.degree. F. to about
1,500.degree. F., more preferably in a range of from about
800.degree. F. to about 1,200.degree. F. The total pressure in the
regeneration zone is preferably in a range of from about 25 pounds
per square inch absolute (psia) to about 500 psia. The partial
pressure of the oxygen-containing compound is generally in a range
of from about 1 percent to about 100 percent of the total pressure.
During regeneration, a substantial portion of the promoter metal
may be returned to its common oxidized (i.e., unreduced) state. The
oxygen-containing stream employed in the regeneration step can be
any composition that, when contacted with the sulfurized sorbent
composition under the above-described regeneration conditions,
promotes the conversion of at least a portion of the zinc sulfide
in/on the sulfurized sorbent composition to zinc oxide, as well as
burns off any remaining hydrocarbon deposits that might be present
on the sulfurized sorbent composition. The oxygen-containing stream
employed in the regeneration step can be pure oxygen or any
oxygen-containing gas(es) such as air. Regeneration is carried out
for a time sufficient to achieve the desired level of sorbent
regeneration. Such regeneration can generally be achieved in a time
period in a range of from about 0.1 hour to about 24 hours,
preferably in a range of from 0.5 hour to 3 hours These parameters
provide for best sorbent regeneration.
[0045] After regeneration, the desulfurized sorbent composition is
subjected to reduction (i.e., activating or re-activating) in an
activation zone with a reducing agent, preferably hydrogen, so that
at least a portion of the unreduced promoter metal of the
regenerated sorbent composition is reduced to thereby provide a
reduced sorbent composition comprising a reduced-valence promoter
metal. Such reduced-valence promoter metal is present in the
sorbent composition in an amount that provides for the removal of
sulfur from a middle distillate according to the process of the
present invention. In general, when practicing the process of the
present invention, the reducing (i.e., activating or re-activating)
of the desulfurized sorbent composition is carried out at a
temperature in a range of from about 100.degree. F. to about
1,500.degree. F. and at a pressure in a range of from about 15
pounds per square inch absolute (psia) to about 1,500 psia.
Reduction is carried out for a time sufficient to achieve the
desired level of promoter metal reduction. Such reduction can
generally be achieved in a time period in a range of from about
0.01 hour to about 20 hours.
[0046] Following the reducing (i.e., activating or re-activating)
of the regenerated, desulfurized sorbent composition, at least a
portion of the resulting reduced (i.e., activated) sorbent
composition can be returned to the reaction zone.
[0047] In carrying out the process of the present invention, a
stripper zone can optionally be inserted before and/or after,
preferably before, regenerating the sulfurized sorbent composition
in the regeneration zone. A similar stripper zone, preferably
utilizing a stripping agent, serves to remove a portion, preferably
all, of any hydrocarbon(s) from the sulfurized sorbent composition.
Such stripper zone can also serve to remove oxygen and sulfur
dioxide from the system prior to introduction of the regenerated
sorbent composition into the activation zone. Preferably, the
stripping, when employed, is carried out at a total pressure in a
range of from about 25 pounds per square inch absolute (psia) to
about 500 psia. The temperature for such stripping can be in a
range of from about 100.degree. F. to about 1,000.degree. F.
Stripping is carried out for a time sufficient to achieve the
desired level of stripping. Such stripping can generally be
achieved in a time period in a range of from about 0.1 hour to
about 4 hours, preferably in a range of from 0.3 hour to 1 hour.
The stripping agent is a composition(s) that helps to remove a
hydrocarbon(s) from the sulfurized sorbent composition. Preferably,
the stripping agent is nitrogen.
[0048] When carrying out the desulfurization process of the present
invention, the steps of desulfurizing, regenerating, reducing
(i.e., activating or re-activating), and optionally stripping
before and/or after such regenerating, can be accomplished in a
single zone or vessel or in multiple zones or vessels. The reaction
zone can be any zone wherein desulfurizing of a middle distillate
fluid, such as diesel fuel, can take place. The regeneration zone
can be any zone wherein regenerating or desulfurizing a sulfurized
sorbent composition can take place. The activation zone can be any
zone wherein reducing (i.e., activating or re-activating), a
regenerated, desulfurized sorbent composition can take place.
Examples of suitable zones are fixed bed reactors, moving bed
reactors, fluidized bed reactors, transport reactors, reactor
vessels, and the like.
[0049] When carrying out the process of the present invention in a
fixed bed reactor system, the step of desulfurizing, regenerating,
reducing and optionally stripping before and/or after such
regenerating are accomplished in a single zone or vessel. When
carrying out the process of the present invention in a fluidized
bed reactor system, the steps of desulfurizing, regenerating,
reducing and optionally stripping before and/or after such
regenerating can be accomplished in multiple zones or vessels.
Preferably, the process of the present invention can be carried out
in a fluidized bed reactor system utilizing multiple zones or
vessels.
[0050] The following example is presented to further illustrate
this invention and is not to be construed as unduly limiting the
scope of this invention.
EXAMPLE
[0051] This example demonstrates that the degree of desulfurization
of diesel fuel is dramatically increased when a hydrogen flow rate
of more than about 1,000 SCFB is employed to vaporize the diesel in
the reaction zone.
[0052] The desulfurization process was carried out by contacting a
sorbent composition with diesel in a fixed bed reactor. The sorbent
composition comprised about 22 weight percent nickel, about 41
weight percent zinc oxide, about 33 weight percent silica, and
about 8 weight percent alumina.
[0053] The diesel feed charged to the reactor comprised a mixture
of hydrocarbons which boiled in a range of from about 293.degree.
F. to about 742.degree. F. and had a mid-boiling point of about
520.degree. F. The diesel feed had an API gravity (ASTM D287-92) of
about 33.2 and contained about 523 parts per million by weight
(ppmw) sulfur.
[0054] The fixed bed reactor was a standard steel reactor having a
3/4 inch inner diameter and a 1/4 inch thermowell.
[0055] The sorbent used in the reactor was in the form of {fraction
(1/16)} inch extrudates. The reactor loading (from bottom up) was
the following:
[0056] (1) 5 inches of R268 support alundum;
[0057] (2) 39 grams of 36 grit alundum;
[0058] (3) Dry packed bed of diluted sorbent-30.5 grams of the
sorbent mixed with 109 grams of 30/40 grit alundum; and
[0059] (4) 26 grams of 36 grit alundum (pre-heat section).
[0060] The testing procedure consisted of a fixed-bed, downflow
feed/hydrogen adsorption, followed by a nitrogen purge, a
nitrogen/air regeneration, another nitrogen purge, and a hydrogen
reduction. The reaction conditions under which the diesel fuel was
contacted with the sorbent composition in the reactor included a
temperature of about 750.degree. F., a pressure of about 500 psig,
and a diesel flow rate of about 2 LHSV.
[0061] Prior to introduction into the reactor, a hydrogen diluent
was combined with the diesel feed. The amount of hydrogen added to
the diesel feed prior to introduction into the reactor was varied
between about 500 SCFB and about 5,000 SCFB. The degree of diesel
desulfurization at the various hydrogen flow rates was determined
by analyzing reactor effluent samples for sulfur content using
x-ray fluorescence. The results are summarized in Table 1 and FIG.
1.
1TABLE 1 Desulfurization of Diesel (523 ppmw sulfur) at Various
H.sub.2 Flow Rates (750.degree. F., 500 psig, 2 LHSV) H.sub.2 Flow
Rate Sulfur Average Sulfur in Recovered (SCFB) Run # (ppmw) Liquid
Product (ppmw) 500 1 15.4 13.9 2 12.9 3 12.6 4 10.6 5 19.2 6 10.8
1,000 1 10.4 10.4 2 10.3 3 11.2 4 9.7 2,500 1 2.0 4.2 2 6.4 3,500 1
5.7 4.7 2 5.4 3 3.1 4,000 1 2.4 2.4 2 3.7 3 0.9 4 2.6 4,500 1 1.3
1.85 2 2.6 3 1.0 4 2.5 5,000 1 2.7 1.66 2 2.1 3 1.2 4 1.7 5 0.6
[0062] Table 1 and FIG. 1 show that as the hydrogen flow rate was
increased above 1,000 SCFB to vaporize the diesel in the reaction
zone, a dramatic increase in sulfur removal was experienced.
[0063] Reasonable variations, modifications, and adaptations can be
made within the scope of this disclosure and the appended claims
without departing from the scope of this invention.
* * * * *