CA2097325A1 - Fluid coking process - Google Patents
Fluid coking processInfo
- Publication number
- CA2097325A1 CA2097325A1 CA 2097325 CA2097325A CA2097325A1 CA 2097325 A1 CA2097325 A1 CA 2097325A1 CA 2097325 CA2097325 CA 2097325 CA 2097325 A CA2097325 A CA 2097325A CA 2097325 A1 CA2097325 A1 CA 2097325A1
- Authority
- CA
- Canada
- Prior art keywords
- zone
- coking
- temperature
- chargestock
- solids
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
- C10B55/00—Coking mineral oils, bitumen, tar, and the like or mixtures thereof with solid carbonaceous material
- C10B55/02—Coking mineral oils, bitumen, tar, and the like or mixtures thereof with solid carbonaceous material with solid materials
- C10B55/04—Coking mineral oils, bitumen, tar, and the like or mixtures thereof with solid carbonaceous material with solid materials with moving solid materials
- C10B55/08—Coking mineral oils, bitumen, tar, and the like or mixtures thereof with solid carbonaceous material with solid materials with moving solid materials in dispersed form
- C10B55/10—Coking mineral oils, bitumen, tar, and the like or mixtures thereof with solid carbonaceous material with solid materials with moving solid materials in dispersed form according to the "fluidised bed" technique
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Dispersion Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
IMPROVED FLUID COKING PROCESS
An improved coking process wherein a heavy hydrocarbonaceous chargestock is partially converted to lower boiling products in a fired heater at temperatures up to, but not including, coking temperatures. The partially converted chargestock is then fed to the scrubbing zone of a fluid coker whereupon the products of conversion are stripped off along with the products from the coking zone of a fluid coking unit. The unconverted hydrocarbonaceous material from the scrubbing zone is fed to the coking zone.
IMPROVED FLUID COKING PROCESS
An improved coking process wherein a heavy hydrocarbonaceous chargestock is partially converted to lower boiling products in a fired heater at temperatures up to, but not including, coking temperatures. The partially converted chargestock is then fed to the scrubbing zone of a fluid coker whereupon the products of conversion are stripped off along with the products from the coking zone of a fluid coking unit. The unconverted hydrocarbonaceous material from the scrubbing zone is fed to the coking zone.
Description
~97325 IMPROVED FLUID COKING PROCESS
FIELD OF THE INVENTION
The present invention relates to an improved coking process wherein a heavy hydrocarbonaceous chargestock is partially converted, or cracked in a first conversion zone, at a temperature below the coking temperature in a fired heater. The partially converted chargestock, with the conversion products, is then fed to the scrubbing zone of a fluid coker whereupon the products are stripped off and the unconverted material is fed to the coking zone.
BACKGROUND_OF THE INVENTION
A substantial amount of work has been done over the years to convert heavy hydrocarbonaceous materials to more valuable lighter boiling products. Various thermal processes which have resulted from such work include visbreaking; hydroconversion, in both a slurry and ebullating bed; fluid coking; and delayed coking.
Of particular interest in the practice of the present invention is improved fluid coking. In fluid coking, a heavy hydrocarbonaceous chargestock, such as a vacuum residuum, is fed to a coking zone comprised of a fluidized bed of hot solid particles, usually coke particles, sometimes also referred to as seed coke. The heavy hydrocarbonaceous material is reacted in the coking zone resulting in conversion products which include a vapor fraction and coke, which coke is deposited on the surface of the seed particles. A portion of the coked-seed particles is sent to a heating zone which is maintained at a temperature higher than that of the coking zone, wherein some of the coke is burned off. Hot seed particles from the heating zone are returned to the coking zone as regenerated seed material which serves as the primary heat source for the coking zone. In an extension of a fluid coking process, a portion of hot coke from the heating zone is circulated back and forth to a gasification zone which is maintained at a temperature higher than that of the heating zone. In the gasifier, substantially all of the remaining coke on the seed material is burned, or gasified, off. Examples of U.S. Patents which teach fluid coking, ~ .
FIELD OF THE INVENTION
The present invention relates to an improved coking process wherein a heavy hydrocarbonaceous chargestock is partially converted, or cracked in a first conversion zone, at a temperature below the coking temperature in a fired heater. The partially converted chargestock, with the conversion products, is then fed to the scrubbing zone of a fluid coker whereupon the products are stripped off and the unconverted material is fed to the coking zone.
BACKGROUND_OF THE INVENTION
A substantial amount of work has been done over the years to convert heavy hydrocarbonaceous materials to more valuable lighter boiling products. Various thermal processes which have resulted from such work include visbreaking; hydroconversion, in both a slurry and ebullating bed; fluid coking; and delayed coking.
Of particular interest in the practice of the present invention is improved fluid coking. In fluid coking, a heavy hydrocarbonaceous chargestock, such as a vacuum residuum, is fed to a coking zone comprised of a fluidized bed of hot solid particles, usually coke particles, sometimes also referred to as seed coke. The heavy hydrocarbonaceous material is reacted in the coking zone resulting in conversion products which include a vapor fraction and coke, which coke is deposited on the surface of the seed particles. A portion of the coked-seed particles is sent to a heating zone which is maintained at a temperature higher than that of the coking zone, wherein some of the coke is burned off. Hot seed particles from the heating zone are returned to the coking zone as regenerated seed material which serves as the primary heat source for the coking zone. In an extension of a fluid coking process, a portion of hot coke from the heating zone is circulated back and forth to a gasification zone which is maintained at a temperature higher than that of the heating zone. In the gasifier, substantially all of the remaining coke on the seed material is burned, or gasified, off. Examples of U.S. Patents which teach fluid coking, ~ .
2~)~7~2~
with or without an integrated gasification zone, are U.S. Patent Nos.
with or without an integrated gasification zone, are U.S. Patent Nos.
3,725,791; 4,203,759; 4,213,848; and 4,269,696; all of which are incorporated herein by reference.
U.S. Patent No. 2,927,073 to Moser et al. teaches a fluid coking process wherein the feedstreams is preheated to a temperature from about 260 to 370C. That is, the feedstream is merely brought to a relatively high temperature prior to being introduced into the fluid coking zone. There is no suggestion of a first conversion zone where only cracking occurs and a second conversion zone where coking occurs.
Notwithstanding any advantages the foregoing processes may have, there is a need in the art to be able to operate fluid coking to increase the conversion of the feed to more desirable liquid products at the expense of less desirable products such as gas and coke.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a fluid coking process, for converting a heavy hydrocarbonaceous chargestock to lower boiling products, comprising the steps of:
(a) partially converting a hydrocarbonaceous chargestock having a Conradson carbon residue of at least 5 wt% in a first conversion zone at a temperature in the range of 400-500C, but below the coking temperature of the chargestock;
(b) introducing the partially converted hydrocarbonaceous chargestock, and any resulting conversion products to a second conversion zone comprised of at least a coking zone and a scrubbing zone, the coking zone comprised of a bed of fluidized refractory solids maintained at fluid conditions, including a temperature from about 450C to about 650C and a total pressure of up to about 150 psig, said partially converted hydrocarbonaceous chargestock and any conversion products from said first conversion zone being introduced into said scrubbing zone wherein there is produced: a vapor phase product, including normally liquid hydrocarbons; and coke, the coke depositing on the fluidized solids;
2 ;;~ 7 3 h (c) introducing a portion of said solids, with coke deposited thereon, into a heating zone comprised of a fluidized bed of refractory solid particles and operated at a temperature from about 35-200C higher than said coking zone and in which the fluidizing gas is sellected from steam and a mixture of steam and an oxygen-containing gas;
(d) recycling a portion of the solids from said heating zone to said coking zone to maintain the temperature of the coking zone between about 450C and 650C; and (e) passing the vapor phase product of step (b) from the coking zone to a scrubbing zone where a lower boiling fraction is collected and a higher boiling fraction is recycled to the coking zone.
In a preferred embodiment of the present invention, the fluidizing gas for the heating zone is only steam and a portion of the solids from the heating zone is passed to a gasification zone which also contains a fluidized bed of refrac~ory solid particles and which is maintained at a temperature greater than that of the heating zone. The fluidizing gas for the gasification zone is a mixture of steam and an oxygen-containing gas.
BRIEF DESCRIPTION OF THE nRAWING
The sole figure hereof is a schematic flow plan of a preferred embodiment of the present invention showing a fired heater for the first conversion zone, and a fluid coking process unit comprised of a coking zone, a heating zone, a gasification zone, and a scrubbing zone for the second conversion zone.
DETAILED DESCRIPTION OF THE INVENTION
Any heavy hydrocarbonaceous material which is typically used as a feed for fluidized coking can be used in the practice of the present invention. Generally, the heavy hydrocarbonaceous material will have a Conradson carbon residue of about 5 to 40 wt.% and be comprised 2 ~ ~ 7 ~ ~ 3 of hydrocarbon components, the majority of which boil above about 525C. Suitable hydrocarbonaceous materials include heavy and reduced petroleum crudes, petroleum atmospheric distillation bottoms, petroleum vacuum distillation bottoms, pitch, asphalt, bitumen, liquid products derived from coal liquefaction processes, including coal liquefaction bottoms, and mixtures thereof.
A typical petroleum chargestock suitable for the practice of the present invention will have composition and properties within the ranges set forth below.
Conradson Carbon 5 to 40 wt.%
Sulfur 1.5 to 8 wt.%
Hydrogen 9 to 11 wt.%
Nitrogen 0.2 to 2 wt.%
Carbon 80 to 86 wt.%
Metals 1 to 2000 wppm Boiling Point 345C+ to 650C+
Specific Gravity -10 to 35 API
The heavy hydrocarbonaceous chargestock is partially converted in a first conversion zone, by feeding it to a fired heater having an exit boil temperature high enough so that cracking of the chargestock occurs~ but not so high that coking occurs. By a temperature where cracking occurs we mean at least that minimum temperature wherein the cracking of higher boiling fractions to lower boiling fractions is significant. Cracking of such feedstocks will typically start at about 400C. Generally, the temperature, as measured at the exit coil of a fired heater will be from about 400C to 500C, preferably from about 425C to 500C, more preferably from about 445C to 485C, and most preferably from about 450C to 475C. The chargestock is converted to the extent that coking does not occur in the first conversion zone. When the partially converted chargestock, along with any conversion products, is fed to the scrubbing zone of the fluid coking unit, the lighter, or cracked products, are flashed and drawn off overhead thereby preventing the products from undergoing secondary reactions in the second conversion zone which would lead to destruction 2d9732~
of the valuable liquid products to gas and coke. The remaining unconverted chargestock is withdrawn from the scrubbing zone and fed to the coking zone.
Reference is now made to the Figure hereof, which shows an integrated fired heater/coking/gasification unit. The fluid coking reaction vessels shown in the figure are similar to those in a conventional fluid coking unit except for the gasification vessel. A
heavy hydrocarbonaceous chargestock is passed via line 10 to fired heater 11 where it is partially converted to lower boiling products to the extent that coking reactions do not occur in the fired heater. That is, it undergoes cracking reactions, but not coking. The exit coil of the fired heater is operated at a temperature as set forth above. The partially converted chargestock is fed via line 13 to scrubbing zone 25 where the products of conversion are drawn off overhead via line 28. By producing cracked, but not coked, products in the fired heater, and drawing them off overhead from the scrubbing zone, serves to prevent such products from undergoing undesirable secondary reactions. This preserves valuable gas oil and naphtha from being degraded to gas and coke. The remaining heavier products are fed via line 26 to coking zone 12, in which is maintained a fluidized bed of refractory solids having an upper level indicated by 14. Although it is preferred that the solids, or seed material, be coke particles, they may also be any other suitable refractory materials. Non-limiting examples of such materials are those selected from the group consisting of silica, alumina, zirconia, magnesia, alumdum or mullite, synthetically prepared or naturally occurring material such as pumice, clay, kieselguhr, diatomaceous earth, bauxite, and the like. The solids will have an average particle size of about 40 to 1000 microns, preferably from about 40 to 400 microns. For purpose of the description of the process of the Figure hereof, the refractory solid particles are coke particles.
A fluidizing gas e.g. steam, is admitted at the base of coker reactor 1, through line 16, in an amount sufficient to obtain superficial fluidizing velocity. Such a velocity is typically in the range of about 0.5 to 5 ft/sec. Coke at a temperature above the coking temperature, for example, at a temperature from about 35 to 200C, 7 ~ 2 ~
preferably from about 65 to 175C, and more preferably about 65C to 120C in excess of the actual operating temperature of the coking zone is admitted to reactor 1 by line 42 from heating zone 2, in an amount sufficient to maintain the coking temperature in the range of about 450 to 650C. The pressure in the coking zone is maintained in the range of about 0 to 1035 kPa, preferably in the range of about 5 to 45 psig. The lower portion of the coking reactor serves as a stripping zone to remove occluded hydrocarbons from the coke. A strea~ of coke is withdrawn from the stripping zone by line 18 and circulated to heater 2.
Conversion products from the coker are passed through cyclone 20 to remove entrained solids which are returned to coking zone through dipleg 22. The vapors leave the cyclone through line 24, and pass into a scrubber 25 mounted on the coking reactor. A stream of heavy materials condensed in the scrubbing zone is recycled along with the unconverted chargestock fed from line 13 to the coking reactor via line 26. The coker conversion products, as well as the conversion products from the fired heater, are removed from the scrubbing zone 25 via line 28 for fractionation in a conventional manner.
In heater 2, stripped coke from coking reactor 1 (cold coke) is introduced by line 1~ to a fluid bed of hot coke having an upper level indicated by 30. The bed is partially heated by passing a fuel gas into the heater by line 32. Supplementary heat is supplied to the heater by coke circulating from gasifier 3 through line 34. The gaseous effluent of the heater, including entrained solids, passes through a cyclone which may be a first cyclone 36 and a second cyclone 38 wherein the separation of the larger entrained solids occur. The separated larger solids are returned to the heater bed via the respective cyclone diplegs 39. The heated gaseous effluent which contains entrained solids is removed from heater 2 via line 40. The fluidizing gas in the heating zone will be steam. In a fluid coking process wherein a gasification zone is not present, the fluidizing gas in the heating zone will be a mixture of steam and an oxygen-containing gas.
Hot coke is removed from the fluidized bed in heater 2 and recycled to coking reactor by line 42 to supply heat thereto.
2097~
Another portion of coke is removed from heater 2 and passed by line 44 to a gasification zone 46 in gasifier 3 in which is maintained a bed of fluidized coke having a level indicated at 48. If desired, a purged stream of coke may be removed from heater 2 by line 50.
The gasification zone is maintained at a temperature ranging from about 870 to 1095C at a pressure ranging from about 0 to 150 psig, preferably at a pressure ranging from about 25 to about 45 psig. Steam by line 52, and a molecular oxygen-containing gas, such as air, commercial oxygen, or air enriched with oxygen by line 54 pass via line 56 into gasifier 3. The reaction of the coke particles in the gasification zone with the steam and the oxygen-containing gas produces a hydrogen and carbon monoxide-containing fuel gas. The gasified product gas, which may further contain some entrained solids, is removed overhead from gasifier 3 by line 32 and introduced into heater 2 to provide a portion of ~he required heat as previously described.
. ~ .
U.S. Patent No. 2,927,073 to Moser et al. teaches a fluid coking process wherein the feedstreams is preheated to a temperature from about 260 to 370C. That is, the feedstream is merely brought to a relatively high temperature prior to being introduced into the fluid coking zone. There is no suggestion of a first conversion zone where only cracking occurs and a second conversion zone where coking occurs.
Notwithstanding any advantages the foregoing processes may have, there is a need in the art to be able to operate fluid coking to increase the conversion of the feed to more desirable liquid products at the expense of less desirable products such as gas and coke.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a fluid coking process, for converting a heavy hydrocarbonaceous chargestock to lower boiling products, comprising the steps of:
(a) partially converting a hydrocarbonaceous chargestock having a Conradson carbon residue of at least 5 wt% in a first conversion zone at a temperature in the range of 400-500C, but below the coking temperature of the chargestock;
(b) introducing the partially converted hydrocarbonaceous chargestock, and any resulting conversion products to a second conversion zone comprised of at least a coking zone and a scrubbing zone, the coking zone comprised of a bed of fluidized refractory solids maintained at fluid conditions, including a temperature from about 450C to about 650C and a total pressure of up to about 150 psig, said partially converted hydrocarbonaceous chargestock and any conversion products from said first conversion zone being introduced into said scrubbing zone wherein there is produced: a vapor phase product, including normally liquid hydrocarbons; and coke, the coke depositing on the fluidized solids;
2 ;;~ 7 3 h (c) introducing a portion of said solids, with coke deposited thereon, into a heating zone comprised of a fluidized bed of refractory solid particles and operated at a temperature from about 35-200C higher than said coking zone and in which the fluidizing gas is sellected from steam and a mixture of steam and an oxygen-containing gas;
(d) recycling a portion of the solids from said heating zone to said coking zone to maintain the temperature of the coking zone between about 450C and 650C; and (e) passing the vapor phase product of step (b) from the coking zone to a scrubbing zone where a lower boiling fraction is collected and a higher boiling fraction is recycled to the coking zone.
In a preferred embodiment of the present invention, the fluidizing gas for the heating zone is only steam and a portion of the solids from the heating zone is passed to a gasification zone which also contains a fluidized bed of refrac~ory solid particles and which is maintained at a temperature greater than that of the heating zone. The fluidizing gas for the gasification zone is a mixture of steam and an oxygen-containing gas.
BRIEF DESCRIPTION OF THE nRAWING
The sole figure hereof is a schematic flow plan of a preferred embodiment of the present invention showing a fired heater for the first conversion zone, and a fluid coking process unit comprised of a coking zone, a heating zone, a gasification zone, and a scrubbing zone for the second conversion zone.
DETAILED DESCRIPTION OF THE INVENTION
Any heavy hydrocarbonaceous material which is typically used as a feed for fluidized coking can be used in the practice of the present invention. Generally, the heavy hydrocarbonaceous material will have a Conradson carbon residue of about 5 to 40 wt.% and be comprised 2 ~ ~ 7 ~ ~ 3 of hydrocarbon components, the majority of which boil above about 525C. Suitable hydrocarbonaceous materials include heavy and reduced petroleum crudes, petroleum atmospheric distillation bottoms, petroleum vacuum distillation bottoms, pitch, asphalt, bitumen, liquid products derived from coal liquefaction processes, including coal liquefaction bottoms, and mixtures thereof.
A typical petroleum chargestock suitable for the practice of the present invention will have composition and properties within the ranges set forth below.
Conradson Carbon 5 to 40 wt.%
Sulfur 1.5 to 8 wt.%
Hydrogen 9 to 11 wt.%
Nitrogen 0.2 to 2 wt.%
Carbon 80 to 86 wt.%
Metals 1 to 2000 wppm Boiling Point 345C+ to 650C+
Specific Gravity -10 to 35 API
The heavy hydrocarbonaceous chargestock is partially converted in a first conversion zone, by feeding it to a fired heater having an exit boil temperature high enough so that cracking of the chargestock occurs~ but not so high that coking occurs. By a temperature where cracking occurs we mean at least that minimum temperature wherein the cracking of higher boiling fractions to lower boiling fractions is significant. Cracking of such feedstocks will typically start at about 400C. Generally, the temperature, as measured at the exit coil of a fired heater will be from about 400C to 500C, preferably from about 425C to 500C, more preferably from about 445C to 485C, and most preferably from about 450C to 475C. The chargestock is converted to the extent that coking does not occur in the first conversion zone. When the partially converted chargestock, along with any conversion products, is fed to the scrubbing zone of the fluid coking unit, the lighter, or cracked products, are flashed and drawn off overhead thereby preventing the products from undergoing secondary reactions in the second conversion zone which would lead to destruction 2d9732~
of the valuable liquid products to gas and coke. The remaining unconverted chargestock is withdrawn from the scrubbing zone and fed to the coking zone.
Reference is now made to the Figure hereof, which shows an integrated fired heater/coking/gasification unit. The fluid coking reaction vessels shown in the figure are similar to those in a conventional fluid coking unit except for the gasification vessel. A
heavy hydrocarbonaceous chargestock is passed via line 10 to fired heater 11 where it is partially converted to lower boiling products to the extent that coking reactions do not occur in the fired heater. That is, it undergoes cracking reactions, but not coking. The exit coil of the fired heater is operated at a temperature as set forth above. The partially converted chargestock is fed via line 13 to scrubbing zone 25 where the products of conversion are drawn off overhead via line 28. By producing cracked, but not coked, products in the fired heater, and drawing them off overhead from the scrubbing zone, serves to prevent such products from undergoing undesirable secondary reactions. This preserves valuable gas oil and naphtha from being degraded to gas and coke. The remaining heavier products are fed via line 26 to coking zone 12, in which is maintained a fluidized bed of refractory solids having an upper level indicated by 14. Although it is preferred that the solids, or seed material, be coke particles, they may also be any other suitable refractory materials. Non-limiting examples of such materials are those selected from the group consisting of silica, alumina, zirconia, magnesia, alumdum or mullite, synthetically prepared or naturally occurring material such as pumice, clay, kieselguhr, diatomaceous earth, bauxite, and the like. The solids will have an average particle size of about 40 to 1000 microns, preferably from about 40 to 400 microns. For purpose of the description of the process of the Figure hereof, the refractory solid particles are coke particles.
A fluidizing gas e.g. steam, is admitted at the base of coker reactor 1, through line 16, in an amount sufficient to obtain superficial fluidizing velocity. Such a velocity is typically in the range of about 0.5 to 5 ft/sec. Coke at a temperature above the coking temperature, for example, at a temperature from about 35 to 200C, 7 ~ 2 ~
preferably from about 65 to 175C, and more preferably about 65C to 120C in excess of the actual operating temperature of the coking zone is admitted to reactor 1 by line 42 from heating zone 2, in an amount sufficient to maintain the coking temperature in the range of about 450 to 650C. The pressure in the coking zone is maintained in the range of about 0 to 1035 kPa, preferably in the range of about 5 to 45 psig. The lower portion of the coking reactor serves as a stripping zone to remove occluded hydrocarbons from the coke. A strea~ of coke is withdrawn from the stripping zone by line 18 and circulated to heater 2.
Conversion products from the coker are passed through cyclone 20 to remove entrained solids which are returned to coking zone through dipleg 22. The vapors leave the cyclone through line 24, and pass into a scrubber 25 mounted on the coking reactor. A stream of heavy materials condensed in the scrubbing zone is recycled along with the unconverted chargestock fed from line 13 to the coking reactor via line 26. The coker conversion products, as well as the conversion products from the fired heater, are removed from the scrubbing zone 25 via line 28 for fractionation in a conventional manner.
In heater 2, stripped coke from coking reactor 1 (cold coke) is introduced by line 1~ to a fluid bed of hot coke having an upper level indicated by 30. The bed is partially heated by passing a fuel gas into the heater by line 32. Supplementary heat is supplied to the heater by coke circulating from gasifier 3 through line 34. The gaseous effluent of the heater, including entrained solids, passes through a cyclone which may be a first cyclone 36 and a second cyclone 38 wherein the separation of the larger entrained solids occur. The separated larger solids are returned to the heater bed via the respective cyclone diplegs 39. The heated gaseous effluent which contains entrained solids is removed from heater 2 via line 40. The fluidizing gas in the heating zone will be steam. In a fluid coking process wherein a gasification zone is not present, the fluidizing gas in the heating zone will be a mixture of steam and an oxygen-containing gas.
Hot coke is removed from the fluidized bed in heater 2 and recycled to coking reactor by line 42 to supply heat thereto.
2097~
Another portion of coke is removed from heater 2 and passed by line 44 to a gasification zone 46 in gasifier 3 in which is maintained a bed of fluidized coke having a level indicated at 48. If desired, a purged stream of coke may be removed from heater 2 by line 50.
The gasification zone is maintained at a temperature ranging from about 870 to 1095C at a pressure ranging from about 0 to 150 psig, preferably at a pressure ranging from about 25 to about 45 psig. Steam by line 52, and a molecular oxygen-containing gas, such as air, commercial oxygen, or air enriched with oxygen by line 54 pass via line 56 into gasifier 3. The reaction of the coke particles in the gasification zone with the steam and the oxygen-containing gas produces a hydrogen and carbon monoxide-containing fuel gas. The gasified product gas, which may further contain some entrained solids, is removed overhead from gasifier 3 by line 32 and introduced into heater 2 to provide a portion of ~he required heat as previously described.
. ~ .
Claims (6)
1. A process for converting a heavy hydrocarbonaceous chargestock having a Conradson carbon residue of at least 5 wt.% to lower boiling products, which process comprises:
(a) partially converting the heavy hydrocarbonaceous chargestock in a first conversion zone at a temperature in the range of 400° to 500°C, but below the coking temperature of said chargestock;
(b) introducing the partially converted chargestock and any conversion products to a second conversion zone comprised of at least a coking zone and a scrubbing zone, the coking zone which is comprised of a bed of refractory solids maintained at fluid conditions, including a temperature from about 450°C to about 650°C and a total pressure of up to about 1035 kPa, said partially converted hydrocarbonaceous chargestock being introduced into said scrubbing zone, wherein there is produced a vapor phase product, including normally liquid hydrocarbons; gas; and coke, the coke depositing on said fluidized solids;
(c) introducing a portion of said solids, with coke deposited thereon into a heating zone comprised of a fluidized bed of refractory solid particles, but operated at a temperature from about 35 to 200°C higher than that of said coking zone, and in which the fluidizing gas is a mixture of steam and an oxygen-containing gas;
(d) recycling a portion of the solids from the heating zone to said coking zone to maintain the temperature of the coking zone between about 450°C and 650°C; and (e) passing the vapor phase product of step (b) from the coking zone to the scrubbing zone where a lower boiling fraction is collected and a higher boiling fraction is recycled to the coking zone.
(a) partially converting the heavy hydrocarbonaceous chargestock in a first conversion zone at a temperature in the range of 400° to 500°C, but below the coking temperature of said chargestock;
(b) introducing the partially converted chargestock and any conversion products to a second conversion zone comprised of at least a coking zone and a scrubbing zone, the coking zone which is comprised of a bed of refractory solids maintained at fluid conditions, including a temperature from about 450°C to about 650°C and a total pressure of up to about 1035 kPa, said partially converted hydrocarbonaceous chargestock being introduced into said scrubbing zone, wherein there is produced a vapor phase product, including normally liquid hydrocarbons; gas; and coke, the coke depositing on said fluidized solids;
(c) introducing a portion of said solids, with coke deposited thereon into a heating zone comprised of a fluidized bed of refractory solid particles, but operated at a temperature from about 35 to 200°C higher than that of said coking zone, and in which the fluidizing gas is a mixture of steam and an oxygen-containing gas;
(d) recycling a portion of the solids from the heating zone to said coking zone to maintain the temperature of the coking zone between about 450°C and 650°C; and (e) passing the vapor phase product of step (b) from the coking zone to the scrubbing zone where a lower boiling fraction is collected and a higher boiling fraction is recycled to the coking zone.
2. The process of claim 1 wherein temperature in said first conversion zone is from about 425°C to 500°C.
3. The process of claim 2 wherein the hydrocarbonaceous chargestock is selected from the group consisting of petroleum vacuum distillation bottoms, pitch, asphalt, bitumen, liquid products derived from coal liquefaction processes, and mixtures thereof.
4. The process of claim 3 wherein the chargestock is petroleum atmospheric or vacuum distillation bottoms.
5. The process of claim 1 wherein a second portion of heated solids from the heating zone of step (d) is passed to a gasification zone comprised of a fluidized bed of solid particles and maintained at a temperature from about 870°C to 1095°C, wherein the fluidizing gas is a mixture of steam and an oxygen-containing gas.
6. The process of claim 4 wherein a second portion of heated solids from the heating zone of step (d) is passed to a gasification zone comprised of a fluidized bed of solid particles and maintained at a temperature from about 1600°F to 2000°F, wherein the fluidizing gas is a mixture of steam and an oxygen-containing gas.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US90331192A | 1992-06-24 | 1992-06-24 | |
| US903,311 | 1992-06-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2097325A1 true CA2097325A1 (en) | 1993-12-25 |
Family
ID=25417288
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2097325 Abandoned CA2097325A1 (en) | 1992-06-24 | 1993-05-28 | Fluid coking process |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPH0657262A (en) |
| CA (1) | CA2097325A1 (en) |
| DE (1) | DE4319559A1 (en) |
| NL (1) | NL9301108A (en) |
-
1993
- 1993-05-28 CA CA 2097325 patent/CA2097325A1/en not_active Abandoned
- 1993-06-09 DE DE19934319559 patent/DE4319559A1/en not_active Withdrawn
- 1993-06-18 JP JP14751993A patent/JPH0657262A/en active Pending
- 1993-06-24 NL NL9301108A patent/NL9301108A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| DE4319559A1 (en) | 1994-01-13 |
| JPH0657262A (en) | 1994-03-01 |
| NL9301108A (en) | 1994-01-17 |
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