CA1117886A - Simultaneous hydrocracking of bitumen/coal slurries - Google Patents
Simultaneous hydrocracking of bitumen/coal slurriesInfo
- Publication number
- CA1117886A CA1117886A CA000320266A CA320266A CA1117886A CA 1117886 A CA1117886 A CA 1117886A CA 000320266 A CA000320266 A CA 000320266A CA 320266 A CA320266 A CA 320266A CA 1117886 A CA1117886 A CA 1117886A
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- Canada
- Prior art keywords
- coal
- hydrocracking
- process according
- hydrogen
- bitumen
- 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.)
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G1/00—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal
- C10G1/08—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal with moving catalysts
- C10G1/083—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal with moving catalysts in the presence of a solvent
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G1/00—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal
- C10G1/06—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal by destructive hydrogenation
- C10G1/065—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal by destructive hydrogenation in the presence of a solvent
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Life Sciences & Earth Sciences (AREA)
- Wood Science & Technology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
- Working-Up Tar And Pitch (AREA)
Abstract
SIMULTANEOUS HYDROCRACKING OF
BITUMEN/COAL SLURRIES
Abstract of the Disclosure A process is described for the simultaneous hydro-cracking of coal and a heavy hydrocarbon, such as bitumen from tar sands. A slurry of the bitumen and coal is passed through a confined hydrocracking zone,and the effluent emerging from the zone is separated into a gaseous stream containing a wide boiling range of material and a liquid stream containing heavy hydrocarbons. This process permits maximum yields from both coal and bitumen, while suppressing coke formation during hydrocracking.
BITUMEN/COAL SLURRIES
Abstract of the Disclosure A process is described for the simultaneous hydro-cracking of coal and a heavy hydrocarbon, such as bitumen from tar sands. A slurry of the bitumen and coal is passed through a confined hydrocracking zone,and the effluent emerging from the zone is separated into a gaseous stream containing a wide boiling range of material and a liquid stream containing heavy hydrocarbons. This process permits maximum yields from both coal and bitumen, while suppressing coke formation during hydrocracking.
Description
~L7~386 This invention relates to hydrocracking and, more particularly, to the simultaneous hydrocracking of coal and a heavy hydrocarbon oil, such as bitumen from tar sands.
Hydrocracking processes for the conversion of heavy hydrocarbon oils to light and intermediate naphthas of good quality for reforming feed stock, fuel oil and gas oil are well known. These heavy hydrocarbon oils can be such materials as petroleum crude oil, atmospheric tar bottoms products, vacuum tar bottoms products, heavy cycle oils, shale oils, coal derived fluids, crude oil residuum, topped crude oils and the heavy bituminous oils extracted from tar sands. Of particular interest are the oils extracted from tar sands which contain wide boiling range materials from naphtha through kerosene, gas oil, pitch, etc., and which contain a large portion, usually more than 50 weight percent of mat-erial boiling above 524C., equivalent atmospheric boiling point.
The heavy hydrocarbon oils of the above type tend to contain nitrogenous and sulphurous compounds in quite large concentrations. In addition, such heavy hydrocarbon fractions frequently contain excessive quantities of organo-metallic contaminants which tend to be extremely detrimental to various catalytic processes that may subsequently be carried out, such as hydrofining. Of the metallic contaminants, those containing nickel and vanadium are most common, although other metals are often present.
These metallic contaminants, as well as others,arP usually present within the bituminous material as organo-metallic compounds of relatively high molecular weight. A considerable quantity of the organometallic complexes are linked ~-ith asphaltenic material and contains sulphur. Of course, in ~ 7~
catalytic hydrocrackiny procedures, the presence of large quantities of asphaltenic material and organic-metallic compounds interferes considerably with the activity of the catalyst with respect to the destructive removal of nitro-genous, sulphurous and oxygenated compounds. A typical Athabasca bitumen may contain 53.76wt. % material boiling above 524C., 4.74-wt. ~ sulphur, 0.59 wt. % nitrogen, 162 ppm vanadium and 72 ppm nickel.
As the reserves of conventional crude oils decline, these heavy oils must be upgraded to meet the demands. In this upgrading, the heavier material is converted to lighter fractions and most of the sulfur, nitrogen and metals must be removed. This is usually done by a coking process such as delayed or fluidized coking or by a hydrogen addition process such as thermal or catalytic hydrocracking. The distillate yield from the coking process is about 70 weight percent and this process also yields about 23 wt. % coke as by-product which cannot be used as fuel because of low hydrogen:carbon ratio, and high mineral and sulfur content. Depending on operating conditions, hydrogenation processes can give a distillate yield of over 87 wt. %.
It has been shown in Ternan et al Canadian patent application serial number 269,020 filed December 31, 1976 and Ranganathan et al., Canadian patent application serial number 289,320, filed October 24, lg77 that the addition of coal or coal-based ca-talyst results in a reduction of coke deposition during hydrocracking and a generally improved operation. The coal additive acts as a l'getterll for coke deposits and prevents accumulation of coke. It is also possible -that coal mineral matter acts as a coke-preventing catalyst. In these previous procedures the hydrogenation of the coal represented only a secondary consideration.
In the hydrocracking of coal, the hydrogen:coal process involves slurrying coal with a coal-derived oil and subsequent reaction with hydrogen at high temperatures and pressures in the presence of Co-Mo/alumina catalyst.
Other processes for converting coal such as SRC (solvent refined coal), EDS (Exxon donor solvent) and Synthoil pro-cesses also recycle distillate fractions derived from coal as solvents. These processes are described, for instance, by Richardson, F.W. "Oil From Coal", Noyes Data Corporation, Parkridge, New Jersey, 1975, 386 pp.
Not only the bitumen, but also the coal contains heavy asphaltenes and mineral matter which rapidly poison the catalyst. This results in excessive catalyst usage and high operating costs. For both bitumen and coal upgrading processes, the fixed bed catalytic processes are not economical because of bed plugging resulting in costly shut-downs. An ebullated bed of catalyst is more suitable for hydrocracking bitumen or coal. Both the hydrogen:coal and the hydrogen:
oil processes use this mode of operation. In the ebullated bed, the upward passage of liquid and gaseous materials main-tains the catalyst in a fluidized state. Catalyst can be added and withdrawn continuously so that a constant activity can be maintained. However, the hydrogen:coal or hydrogen:
oil process uses an expensive Co-Mo/alumina catalyst which deactivates rapidly at high conversions, resulting in excessive operating costs.
As has been shown in the above patent applications, the operating costs can be reduced by using cheap throw-away type catalysts and, for instance, serial number 289,320 des-cribes the use of iron-coal catalyst which enables operation at lower pressures and at higher conversions. The use of 8~
coal and Co, Mo and Al on coal catalysts are described in serial number 269,020.
It is the object of the present invention to take advantage of the solvent and hydrogen donor action of a bitu-men feed stock as well as the catalytic action of coal mineral ma-tter so as to provide a novel hydrocracking process showing improved economics.
SUMMARY OF THE INVENTION
.. . ......
In accordance with the present invention, there is described a process for hydrocracking a heavy hydrocarbon oil, a substantial portion of which boils above 524C., which comprises:
a) passing a slurry of said heavy hydrocarbon oil and from about 2 - 50 wt. ~ coal in the presence of 50~-50,000 s.c.f. of hydrogen per barrel of said hydrocarbon oil through a confined hydrocracking zone, said hydrocracking zone being maintained at a temperature between about 400 and 500C., : a pressure of at least 200 psig. and a space velocity between about 0.5 and 4 volume of hydrocarbon oil per hour per volume of hydrocracking zone capacity, b) removing from said hydrocracking zone a mixed effluent containing a gaseous phase comprising hydrogen and vaporous hydrocarbons and a liquid phase comprising heavy hydrocarbons, and c) separating said effluent into a gaseous stream containing hydrogen and vaporous hydrocarbons and a liquid stream containing heavy hydrocarbons.
This process provides a simultaneous hydrocracking of the heavy oil and coal, with the heavy oil acting as a good solvent vehicle and the coal acting as a catalyst, preventing coke formation reactions.
~7~86 ~ 7hile the process of this invention is particularly well suited for the treatment of bitumen, it is also very well suited for the treatment of topped bitumen or pitch.
It can be operated at quite moderate pressures, e.g. in the range of 200 to 3,500 psig, without coke formation in the hydrocracking zone.
The hydrocracking process of this inv~ntion can be carried out in a variety of known reactors with either up or down flow. Thus, the hydrocracking reactor zone can be an empty tubular reactor, an ebullated bed reactor or a fluidized bed reactor. The empty tubular reactor has been found to be particularly convenient with the effluent from the top being separated in a hot separator and the gaseous stream from the hot separator being fed to a low temperature-high pressure separator where it is separated into a gaseous stream containing hydrogen and lesser amounts of gaseous hydrocarbons and a liquid product stream containing light oil products. It is also possible to have the reactors in stages where the first reactor is an empty tubular reactor and the second reactor contains an ebullated bed of catalyst extrudates.
Any type of coal, such as lignite, sub-bituminous, bituminous, etc., can be used as the coal portion of the charge slurry. The coal can be used as is without any additive or it may be coated with up to about 10 wt.~ of metal salts such as iron, cobalt, molybdenum, zinc, tin, tungsten, nickel or other catalytically active salts. The use of the catalytic materials improve the conversion of coal and bituman as well as the operability of the process, but the metal loading must depend on the cost of materials, tolerable ash content and optimum catalyst activity.
The catalyst can be coated on the coal by spraying the aqueous solution of the metal salt on the coal particles.
~178~;
The coal is then dried to reduce the moisture content before blending with the feed stock.
The coal particles used should be quite small, ~.g.
less than 60 mesh (Canadian Standard Seive) and it is parti-cularly preferred to use a material which will pass through a 100 mesh sieve. The coal should be mixed with the bitumen in such a manner as to avoid formation of lumps and, if desired, additional homogeneous or heterogeneous catalysts may be mixed with the coal-bitumen slurry.
The simultaneous hydrogenation process produces pitch which contains asphaltenes, ash and residues from both bitumen and coal. Depending on the type of coal used, and the feed stock, the pitch properties vary. For example, low sulfur sub-bituminous coals obtained from Western Canada produce a low-sulfur pitch. This reduces the cost of s-tack gas cleanup, while increasing the ash content of the pitch.
The presence of the large amounts of coal in the slurry, as stated above, suppresses coke formation during hydrocracking. The result is that the simultaneous coal-bitumen hydrocracking can be performed at quite low pressures.Nevertheless, in certain situations it is desirable to operate at higher pressures so as to maximize liquid yields as well as product quality.
According to a preferred embodiment, the bitumen and coal are mixed in a feed tank and pumped with hydrogen through a vertical empty tube reactor. The liquid-gas mix-ture from the top of the hydrocracking zone is separated in a hot separator maintained at a temperature in the range of about 200 - 470~C. and at the pressure of the hydrocracking zone. The heavy hydrocarbon product from the hot separator can be partially recycled to the hydrocracking zone or sent to secondary treatment.
The gaseous stream from the ho-t separator contain-ing a mixture of hydrocarbon gases and hydrogen is further cooled and separated in a low temperature-high pressure separator. By using this type of separator, the outlet gaseous stream obtained contains mostly hydrogen with some impurities such as hydrogen sulfide and light hydrocarbon gases. This gaseous stream is passed through a scrubber and the scrubbed hydrogen is recycled as part of the hydrogen feed to the hydrocracking process. The recycled hydrogen gas purity is maintained by adjusting scrubbing conditions and by adding make-up hydrogen.
The liquid stream from the low temperature- high pressure separator represents the light hydrocarbon product of the present process and can be sent for secondary treat-ment.
Some of the coal may be carried over with the heavy oil product from the hot separator and found in the 524C.+
pitch fraction. This coal can conveniently be burned or gasified with the pitch.
For a better understanding of the invention, ref-erence is made to the accompanying drawing which illustrates diagrammatically a preferred embodiment of the present invention.
Heavy hydrocarbon oil feed and coal are mixed together in a feed tank 10 to form a slurry. This slurry is pumped via feed pump 11 through inlet line 12 into the bottom of an empty tower 13. Recycled hydrogen and make up hydrogen from line 30 is simultaneously fed into the tower 13 throuyh line 12. A gas-liquid mixture is wi-thdrawn from the top of the -tower through line 14 and introduced into a hot 1~ 8~
separator 15. In the hot separator the effluent from tower 13 is separated into a gaseous stream 18 and a liyuid stream 16. The liquid stream 16 is in the form of heavy oil which is collected at 17.
The gaseous stream from hot separator 15 is carried by way of line 18 into a high pressure-low temp-erature separator l9. Within -this separator the product is separated into a gaseous stream rich in hydrogen which is drawn off through line 22 and an oil product which is drawn off through line 20 and collected at 21.
The hydrogen rich stream 2Z is passed through a packed scrubbing tower 23 where it is scrubbed by means of a scrubbing liquid 24 which is cycled through the tower by means of pump 25 and recycle loop 26. The scrubbed hydrogen rich stream emerges from the scrubber via line 27 and is combined with fresh make up hydrogen added through line 28 and recycled through recycle gas pump 29 and line 30 ~ack to tower 13.
Certain preferred embodiments of this invention will now be further illustrated by the following non-limitative examples.
Example 1.
A sub-bituminous coal was obtained from the '~hite Wood coal mine and this coal had the following properties:
Calorific Value*, kJ/kg25900 Carbon*, wt. % 67.1 Hydrogen*, wt. % 4.0 Sulphur*, wt. % 0.2 Nitrogen*, wt. % 0.9 Ash*, wt. % 9 5 Oxygen, wt. % ~by difference) 18.3 Moisture (as received), wt.% 9.6 Pentane Insolubles, wt. % 94.8 Toluene Insolub]es, wt. % 91.6 * Properties of coal on dry basis.
The above coal was crushed and screened to provide a 60 mesh material.
~78~
The bitumen used was an Athabasca bitumen having the following properties: , Specific Gravity, 15/15C. 1.013 Sulphur, wt.% 4.74 Nitrogen, wt. % 0.59 Ash , wt. % 0.59 Viscosity at 99C., cst 213 Conradson Carbon Residue, wt.% 14.9 Pentane insolubles, wt. ~ 16.8 Benzene insolubles, wt.~ 0.52 Nickel, ppm (wt) 72 Vanadium, ppm (wt.) 162 Pitch content, wt. %53.76 Sulphur in 524C.- dist., wt.% 2.96 Sulphur in 524C+ pitch, wt.% 6.18 A blended slurry of the bitumen and 10% by weight of the coal was prepared and this slurry was used as the feedstock to a hydrocrackiny pilot plant. The pilot plant used the reaction sequence shown in the attached drawing and was operated under the following reaction conditions:
Reaction pressure, psig. 2000 Reactor temperature, C. 460 Feed rate, g/h 9000 Gas rate, scf/h 197.0 Hydrogen, concentration, vol.% 85.0 Hot separator temperature, C. 370 - 20 The results obtained ~rom this run were as follows:
Pitch* (524C.~) conversion, wt.% 74.85 Sulphur conversion, wt. % 45.3 Hydrogen consumed, scf/bbl 786 Product volume yield, vol. %97.6 Product weight yield, wt. % 90.9 Product gravity, 15/15C. 0.943 Sulphur in 524C.- distillate, wt.% 2.33 Pitch in product, wt. % 16.16 Ash in product pitch, wt. % 11.0 Sulphur in pitch, wt. % 3.43 * Includes coal-based on pitch determination on feed, in-cluding coal; and product, including coal.
Example 2 The above hydrocracking procedure was repe~ted under identical conditions, but without the addition o~ any coal to the bitumen charge stock. The results obtained were as follows:
Pitch (524C+ conv.), wt. % 76.1 Sulphur conversion, wt. % 45.4 Hydrogen consumed, scf/bbl 847 Product gravity, 15/15C. 0.928 Sulphur in 524C- dist., wt. % 2.54 Sulphur in pitch, wt. % 5.12 From the above examples it will be seen that the pitch conversion in the presence of coal compared very favorably to conversion in the procedure without coal.
The degree of sulphur removal was also similar. The major difference was the sulphur content of the pitch.
Based on material balance of sulphur and pentane insolubles, it has been found that close to 50% of the coal has been converted to either liquid or gaseous products.
Based on the carbon content of the coal as received (60.7 Wt. %), conversion to liquids is about 82~ of possible carbon conversion and based on the estimate that only 50% of the coal added remained in the product pitch, the conversion of the bitumen-pitch fractlon is in the order of 82%. This indicates that the presence of coal significantly enhances liquid yield, resulting in a more efficient process, together with the added advantage of providing a pitch of decreased sulphur content. The conversion of coal and liquid product qualities can be varied with the catalytically active metal salts or type of coal used.
Hydrocracking processes for the conversion of heavy hydrocarbon oils to light and intermediate naphthas of good quality for reforming feed stock, fuel oil and gas oil are well known. These heavy hydrocarbon oils can be such materials as petroleum crude oil, atmospheric tar bottoms products, vacuum tar bottoms products, heavy cycle oils, shale oils, coal derived fluids, crude oil residuum, topped crude oils and the heavy bituminous oils extracted from tar sands. Of particular interest are the oils extracted from tar sands which contain wide boiling range materials from naphtha through kerosene, gas oil, pitch, etc., and which contain a large portion, usually more than 50 weight percent of mat-erial boiling above 524C., equivalent atmospheric boiling point.
The heavy hydrocarbon oils of the above type tend to contain nitrogenous and sulphurous compounds in quite large concentrations. In addition, such heavy hydrocarbon fractions frequently contain excessive quantities of organo-metallic contaminants which tend to be extremely detrimental to various catalytic processes that may subsequently be carried out, such as hydrofining. Of the metallic contaminants, those containing nickel and vanadium are most common, although other metals are often present.
These metallic contaminants, as well as others,arP usually present within the bituminous material as organo-metallic compounds of relatively high molecular weight. A considerable quantity of the organometallic complexes are linked ~-ith asphaltenic material and contains sulphur. Of course, in ~ 7~
catalytic hydrocrackiny procedures, the presence of large quantities of asphaltenic material and organic-metallic compounds interferes considerably with the activity of the catalyst with respect to the destructive removal of nitro-genous, sulphurous and oxygenated compounds. A typical Athabasca bitumen may contain 53.76wt. % material boiling above 524C., 4.74-wt. ~ sulphur, 0.59 wt. % nitrogen, 162 ppm vanadium and 72 ppm nickel.
As the reserves of conventional crude oils decline, these heavy oils must be upgraded to meet the demands. In this upgrading, the heavier material is converted to lighter fractions and most of the sulfur, nitrogen and metals must be removed. This is usually done by a coking process such as delayed or fluidized coking or by a hydrogen addition process such as thermal or catalytic hydrocracking. The distillate yield from the coking process is about 70 weight percent and this process also yields about 23 wt. % coke as by-product which cannot be used as fuel because of low hydrogen:carbon ratio, and high mineral and sulfur content. Depending on operating conditions, hydrogenation processes can give a distillate yield of over 87 wt. %.
It has been shown in Ternan et al Canadian patent application serial number 269,020 filed December 31, 1976 and Ranganathan et al., Canadian patent application serial number 289,320, filed October 24, lg77 that the addition of coal or coal-based ca-talyst results in a reduction of coke deposition during hydrocracking and a generally improved operation. The coal additive acts as a l'getterll for coke deposits and prevents accumulation of coke. It is also possible -that coal mineral matter acts as a coke-preventing catalyst. In these previous procedures the hydrogenation of the coal represented only a secondary consideration.
In the hydrocracking of coal, the hydrogen:coal process involves slurrying coal with a coal-derived oil and subsequent reaction with hydrogen at high temperatures and pressures in the presence of Co-Mo/alumina catalyst.
Other processes for converting coal such as SRC (solvent refined coal), EDS (Exxon donor solvent) and Synthoil pro-cesses also recycle distillate fractions derived from coal as solvents. These processes are described, for instance, by Richardson, F.W. "Oil From Coal", Noyes Data Corporation, Parkridge, New Jersey, 1975, 386 pp.
Not only the bitumen, but also the coal contains heavy asphaltenes and mineral matter which rapidly poison the catalyst. This results in excessive catalyst usage and high operating costs. For both bitumen and coal upgrading processes, the fixed bed catalytic processes are not economical because of bed plugging resulting in costly shut-downs. An ebullated bed of catalyst is more suitable for hydrocracking bitumen or coal. Both the hydrogen:coal and the hydrogen:
oil processes use this mode of operation. In the ebullated bed, the upward passage of liquid and gaseous materials main-tains the catalyst in a fluidized state. Catalyst can be added and withdrawn continuously so that a constant activity can be maintained. However, the hydrogen:coal or hydrogen:
oil process uses an expensive Co-Mo/alumina catalyst which deactivates rapidly at high conversions, resulting in excessive operating costs.
As has been shown in the above patent applications, the operating costs can be reduced by using cheap throw-away type catalysts and, for instance, serial number 289,320 des-cribes the use of iron-coal catalyst which enables operation at lower pressures and at higher conversions. The use of 8~
coal and Co, Mo and Al on coal catalysts are described in serial number 269,020.
It is the object of the present invention to take advantage of the solvent and hydrogen donor action of a bitu-men feed stock as well as the catalytic action of coal mineral ma-tter so as to provide a novel hydrocracking process showing improved economics.
SUMMARY OF THE INVENTION
.. . ......
In accordance with the present invention, there is described a process for hydrocracking a heavy hydrocarbon oil, a substantial portion of which boils above 524C., which comprises:
a) passing a slurry of said heavy hydrocarbon oil and from about 2 - 50 wt. ~ coal in the presence of 50~-50,000 s.c.f. of hydrogen per barrel of said hydrocarbon oil through a confined hydrocracking zone, said hydrocracking zone being maintained at a temperature between about 400 and 500C., : a pressure of at least 200 psig. and a space velocity between about 0.5 and 4 volume of hydrocarbon oil per hour per volume of hydrocracking zone capacity, b) removing from said hydrocracking zone a mixed effluent containing a gaseous phase comprising hydrogen and vaporous hydrocarbons and a liquid phase comprising heavy hydrocarbons, and c) separating said effluent into a gaseous stream containing hydrogen and vaporous hydrocarbons and a liquid stream containing heavy hydrocarbons.
This process provides a simultaneous hydrocracking of the heavy oil and coal, with the heavy oil acting as a good solvent vehicle and the coal acting as a catalyst, preventing coke formation reactions.
~7~86 ~ 7hile the process of this invention is particularly well suited for the treatment of bitumen, it is also very well suited for the treatment of topped bitumen or pitch.
It can be operated at quite moderate pressures, e.g. in the range of 200 to 3,500 psig, without coke formation in the hydrocracking zone.
The hydrocracking process of this inv~ntion can be carried out in a variety of known reactors with either up or down flow. Thus, the hydrocracking reactor zone can be an empty tubular reactor, an ebullated bed reactor or a fluidized bed reactor. The empty tubular reactor has been found to be particularly convenient with the effluent from the top being separated in a hot separator and the gaseous stream from the hot separator being fed to a low temperature-high pressure separator where it is separated into a gaseous stream containing hydrogen and lesser amounts of gaseous hydrocarbons and a liquid product stream containing light oil products. It is also possible to have the reactors in stages where the first reactor is an empty tubular reactor and the second reactor contains an ebullated bed of catalyst extrudates.
Any type of coal, such as lignite, sub-bituminous, bituminous, etc., can be used as the coal portion of the charge slurry. The coal can be used as is without any additive or it may be coated with up to about 10 wt.~ of metal salts such as iron, cobalt, molybdenum, zinc, tin, tungsten, nickel or other catalytically active salts. The use of the catalytic materials improve the conversion of coal and bituman as well as the operability of the process, but the metal loading must depend on the cost of materials, tolerable ash content and optimum catalyst activity.
The catalyst can be coated on the coal by spraying the aqueous solution of the metal salt on the coal particles.
~178~;
The coal is then dried to reduce the moisture content before blending with the feed stock.
The coal particles used should be quite small, ~.g.
less than 60 mesh (Canadian Standard Seive) and it is parti-cularly preferred to use a material which will pass through a 100 mesh sieve. The coal should be mixed with the bitumen in such a manner as to avoid formation of lumps and, if desired, additional homogeneous or heterogeneous catalysts may be mixed with the coal-bitumen slurry.
The simultaneous hydrogenation process produces pitch which contains asphaltenes, ash and residues from both bitumen and coal. Depending on the type of coal used, and the feed stock, the pitch properties vary. For example, low sulfur sub-bituminous coals obtained from Western Canada produce a low-sulfur pitch. This reduces the cost of s-tack gas cleanup, while increasing the ash content of the pitch.
The presence of the large amounts of coal in the slurry, as stated above, suppresses coke formation during hydrocracking. The result is that the simultaneous coal-bitumen hydrocracking can be performed at quite low pressures.Nevertheless, in certain situations it is desirable to operate at higher pressures so as to maximize liquid yields as well as product quality.
According to a preferred embodiment, the bitumen and coal are mixed in a feed tank and pumped with hydrogen through a vertical empty tube reactor. The liquid-gas mix-ture from the top of the hydrocracking zone is separated in a hot separator maintained at a temperature in the range of about 200 - 470~C. and at the pressure of the hydrocracking zone. The heavy hydrocarbon product from the hot separator can be partially recycled to the hydrocracking zone or sent to secondary treatment.
The gaseous stream from the ho-t separator contain-ing a mixture of hydrocarbon gases and hydrogen is further cooled and separated in a low temperature-high pressure separator. By using this type of separator, the outlet gaseous stream obtained contains mostly hydrogen with some impurities such as hydrogen sulfide and light hydrocarbon gases. This gaseous stream is passed through a scrubber and the scrubbed hydrogen is recycled as part of the hydrogen feed to the hydrocracking process. The recycled hydrogen gas purity is maintained by adjusting scrubbing conditions and by adding make-up hydrogen.
The liquid stream from the low temperature- high pressure separator represents the light hydrocarbon product of the present process and can be sent for secondary treat-ment.
Some of the coal may be carried over with the heavy oil product from the hot separator and found in the 524C.+
pitch fraction. This coal can conveniently be burned or gasified with the pitch.
For a better understanding of the invention, ref-erence is made to the accompanying drawing which illustrates diagrammatically a preferred embodiment of the present invention.
Heavy hydrocarbon oil feed and coal are mixed together in a feed tank 10 to form a slurry. This slurry is pumped via feed pump 11 through inlet line 12 into the bottom of an empty tower 13. Recycled hydrogen and make up hydrogen from line 30 is simultaneously fed into the tower 13 throuyh line 12. A gas-liquid mixture is wi-thdrawn from the top of the -tower through line 14 and introduced into a hot 1~ 8~
separator 15. In the hot separator the effluent from tower 13 is separated into a gaseous stream 18 and a liyuid stream 16. The liquid stream 16 is in the form of heavy oil which is collected at 17.
The gaseous stream from hot separator 15 is carried by way of line 18 into a high pressure-low temp-erature separator l9. Within -this separator the product is separated into a gaseous stream rich in hydrogen which is drawn off through line 22 and an oil product which is drawn off through line 20 and collected at 21.
The hydrogen rich stream 2Z is passed through a packed scrubbing tower 23 where it is scrubbed by means of a scrubbing liquid 24 which is cycled through the tower by means of pump 25 and recycle loop 26. The scrubbed hydrogen rich stream emerges from the scrubber via line 27 and is combined with fresh make up hydrogen added through line 28 and recycled through recycle gas pump 29 and line 30 ~ack to tower 13.
Certain preferred embodiments of this invention will now be further illustrated by the following non-limitative examples.
Example 1.
A sub-bituminous coal was obtained from the '~hite Wood coal mine and this coal had the following properties:
Calorific Value*, kJ/kg25900 Carbon*, wt. % 67.1 Hydrogen*, wt. % 4.0 Sulphur*, wt. % 0.2 Nitrogen*, wt. % 0.9 Ash*, wt. % 9 5 Oxygen, wt. % ~by difference) 18.3 Moisture (as received), wt.% 9.6 Pentane Insolubles, wt. % 94.8 Toluene Insolub]es, wt. % 91.6 * Properties of coal on dry basis.
The above coal was crushed and screened to provide a 60 mesh material.
~78~
The bitumen used was an Athabasca bitumen having the following properties: , Specific Gravity, 15/15C. 1.013 Sulphur, wt.% 4.74 Nitrogen, wt. % 0.59 Ash , wt. % 0.59 Viscosity at 99C., cst 213 Conradson Carbon Residue, wt.% 14.9 Pentane insolubles, wt. ~ 16.8 Benzene insolubles, wt.~ 0.52 Nickel, ppm (wt) 72 Vanadium, ppm (wt.) 162 Pitch content, wt. %53.76 Sulphur in 524C.- dist., wt.% 2.96 Sulphur in 524C+ pitch, wt.% 6.18 A blended slurry of the bitumen and 10% by weight of the coal was prepared and this slurry was used as the feedstock to a hydrocrackiny pilot plant. The pilot plant used the reaction sequence shown in the attached drawing and was operated under the following reaction conditions:
Reaction pressure, psig. 2000 Reactor temperature, C. 460 Feed rate, g/h 9000 Gas rate, scf/h 197.0 Hydrogen, concentration, vol.% 85.0 Hot separator temperature, C. 370 - 20 The results obtained ~rom this run were as follows:
Pitch* (524C.~) conversion, wt.% 74.85 Sulphur conversion, wt. % 45.3 Hydrogen consumed, scf/bbl 786 Product volume yield, vol. %97.6 Product weight yield, wt. % 90.9 Product gravity, 15/15C. 0.943 Sulphur in 524C.- distillate, wt.% 2.33 Pitch in product, wt. % 16.16 Ash in product pitch, wt. % 11.0 Sulphur in pitch, wt. % 3.43 * Includes coal-based on pitch determination on feed, in-cluding coal; and product, including coal.
Example 2 The above hydrocracking procedure was repe~ted under identical conditions, but without the addition o~ any coal to the bitumen charge stock. The results obtained were as follows:
Pitch (524C+ conv.), wt. % 76.1 Sulphur conversion, wt. % 45.4 Hydrogen consumed, scf/bbl 847 Product gravity, 15/15C. 0.928 Sulphur in 524C- dist., wt. % 2.54 Sulphur in pitch, wt. % 5.12 From the above examples it will be seen that the pitch conversion in the presence of coal compared very favorably to conversion in the procedure without coal.
The degree of sulphur removal was also similar. The major difference was the sulphur content of the pitch.
Based on material balance of sulphur and pentane insolubles, it has been found that close to 50% of the coal has been converted to either liquid or gaseous products.
Based on the carbon content of the coal as received (60.7 Wt. %), conversion to liquids is about 82~ of possible carbon conversion and based on the estimate that only 50% of the coal added remained in the product pitch, the conversion of the bitumen-pitch fractlon is in the order of 82%. This indicates that the presence of coal significantly enhances liquid yield, resulting in a more efficient process, together with the added advantage of providing a pitch of decreased sulphur content. The conversion of coal and liquid product qualities can be varied with the catalytically active metal salts or type of coal used.
Claims (9)
1. A process for hydrocracking a heavy hydro-carbon oil, a substantial proportion of which boils above 524°C. which comprises:
(a) passing a slurry of said heavy hydro-carbon oil and 2 -to 50 wt. % coal in the presence of 500 - 50,000 s.c.f. of hydrogen per barrel of said hydro-carbon oil through a confined hydrocracking zone, said hydrocracking zone being maintained at a temperature be-tween about 400 and 500°C., a pressure above 200 psig and a space velocity between about 0.5 and 4.0 volumes of heavy hydrocarbon oil per hour per volume of hydrocrackinq zone capacity, (b) removing from said hydrocracking zone a mixed effluent containing a gaseous phase comprising hydrogen and vaporous hydrocarbons and a liquid phase com-prising heavy hydrocarbons, and (c) separating said effluent into a qaseous stream containing hydrogen and vaporous hydrocarbons and a liquid stream containing heavy hydrocarbons.
(a) passing a slurry of said heavy hydro-carbon oil and 2 -to 50 wt. % coal in the presence of 500 - 50,000 s.c.f. of hydrogen per barrel of said hydro-carbon oil through a confined hydrocracking zone, said hydrocracking zone being maintained at a temperature be-tween about 400 and 500°C., a pressure above 200 psig and a space velocity between about 0.5 and 4.0 volumes of heavy hydrocarbon oil per hour per volume of hydrocrackinq zone capacity, (b) removing from said hydrocracking zone a mixed effluent containing a gaseous phase comprising hydrogen and vaporous hydrocarbons and a liquid phase com-prising heavy hydrocarbons, and (c) separating said effluent into a qaseous stream containing hydrogen and vaporous hydrocarbons and a liquid stream containing heavy hydrocarbons.
2. A process according to claim 1 wherein the coal is -60 mesh (Canadian Sieve).
3. The process according to claim 2 wherein the coal is selected from sub-bituminous, bituminous, and lignite coal.
4. A process according to claim 1, 2 or 3, wherein the feed slurry is moved upwardly through a tubular reactor.
5. A process according to claim 1 wherein the coal is coated with up to about 10 wt. % of a metal salt catalyst.
6. A process according to claim 5 wherein the metal salt is a salt of iron, cobalt, molybdenum, zinc, tin, nickel or tungsten.
7. A process according to claim 1, 2 or 3 wherein the hydrocracking is conducted at a pressure in the range of 200 - 3,500 psig.
8. A process according to claim 1 wherein the mixed effluent is separated in a hot separator.
9. A process according to claim 8 wherein the gaseous stream from the hot separator is cooled and separated in a low temperature separator into a gaseous stream containing hydrogen and lesser amounts of gaseous hydrocarbons and a liquid product stream containing light oil products.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000320266A CA1117886A (en) | 1979-01-25 | 1979-01-25 | Simultaneous hydrocracking of bitumen/coal slurries |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000320266A CA1117886A (en) | 1979-01-25 | 1979-01-25 | Simultaneous hydrocracking of bitumen/coal slurries |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1117886A true CA1117886A (en) | 1982-02-09 |
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ID=4113398
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000320266A Expired CA1117886A (en) | 1979-01-25 | 1979-01-25 | Simultaneous hydrocracking of bitumen/coal slurries |
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| Country | Link |
|---|---|
| CA (1) | CA1117886A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1993022405A1 (en) * | 1992-04-30 | 1993-11-11 | Mezhdunarodny Biznes-Tsentr 'alfa' | Method of obtaining fuel distillates |
| US5350430A (en) * | 1992-08-27 | 1994-09-27 | Energy Mines And Resources-Canada | Oil/coal coprocessing in which agglomerated coal forms part of feedstock |
-
1979
- 1979-01-25 CA CA000320266A patent/CA1117886A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1993022405A1 (en) * | 1992-04-30 | 1993-11-11 | Mezhdunarodny Biznes-Tsentr 'alfa' | Method of obtaining fuel distillates |
| US5350430A (en) * | 1992-08-27 | 1994-09-27 | Energy Mines And Resources-Canada | Oil/coal coprocessing in which agglomerated coal forms part of feedstock |
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