Gulf Research & Development Company

Gulf Oil Corporation

The Pittsburg & Midway Coal Mining Co.

Norman L Carr

Edgar L McGinnis

Bruce K Schmid

Yatish T Shah

Michael E Prudich

William G Moon

Ronald Schleppy, Jr

William E King, Jr

A process for preventing the formation of deleterious coke deposits on the walls of coal liquefaction reactor vessels involves passing hydrogen and a feed slurry comprising feed coal and recycle liquid solvent to a coal liquefaction reaction zone while imparting a critical mixing energy of at least 3500 ergs per cubic centimeter of reaction zone volume per second to the reacting slurry.

Prevention of deleterious deposits in a coal liquefaction system

A C.sub.5 -900.degree. F. (C.sub.5 -482.degree. C.) liquid yield greater than 50 weight percent MAF feed coal is obtained in a coal liquefaction process wherein a selected combination of higher hydrogen partial pressure, longer slurry residence time and increased recycle ash content of the feed slurry are controlled within defined ranges.

Coal liquefaction process

The rate of filtration of a coal liquid slurry is increased by adding polyisobutylene and an alcohol containing 2 to 10 carbon atoms to the slurry prior to filtration or by adding the alcohol to the slurry and washing a precoat cake of filter aid with an oil solution of polyisobutylene prior to filtration. Although the polyisobutylene and the alcohol each provides a filtration rate improving effect when used alone, a synergistic improvement in filtration rate is achieved by their combined use.

Filtration of a coal liquid slurry using polyisobutylene and an alcohol

The rate of filtration of a coal liquid slurry is increased by adding an alkylmethacrylate copolymer and an alcohol containing 2 to 10 carbon atoms to the slurry prior to filtration or by adding the alcohol to the slurry and washing a precoat cake of filter aid with an oil solution of an alkylmethacrylate copolymer prior to filtration. Although the alkylmethacrylate copolymer and the alcohol each provide a filter rate improving effect when used alone, a synergistic improvement in filtration rate is achieved by their combined use.

Filtration of a coal liquid slurry using an alkylmethacrylate copolymer

The rate of filtration of a coal liquid slurry is increased by adding an alkylmethacrylate copolymer to the slurry prior to filtration or by washing a precoat cake of filter aid with an oil solution of the alkylmethacrylate copolymer prior to filtration.

The rate of filtration of a coal liquid slurry is increased by adding an ethylene vinyl acetate copolymer and an alcohol containing 2 to 10 carbon atoms to the slurry prior to filtration or by adding the alcohol to the slurry and washing a precoat cake of filter aid with an oil solution of ethylene vinyl acetate copolymer prior to filtration. Although the ethylene vinyl acetate copolymer and the alcohol each provides a filter rate improving effect when used alone, a synergistic improvement in filtration rate is achieved by their combined use.

Filtration of a coal liquid slurry using an ethylene vinyl acetate

The rate of filtration of a coal liquid slurry is increased by adding ethylene vinyl acetate copolymer to the slurry prior to filtration or by washing a precoat cake of filter aid with an oil solution of ethylene vinyl acetate copolymer prior to filtration.

The rate of filtration of a coal liquid slurry is increased by adding polyisobutylene to the slurry prior to filtration or by washing a precoat cake of filter aid with an oil solution of polyisobutylene prior to filtration.

Filtration of a coal liquid slurry using polyisobutylene

In a coal liquefaction process the yield of liquid coal is increased with a concomitant decrease in the yield of normally solid dissolved coal by recycle of a product slurry containing mineral residue. In an integrated coal liquefaction-gasification process employing product slurry recycle wherein the net yield of normally solid dissolved coal from the liquefaction zone comprises the entire hydrocarbonaceous feed to the gasification zone, a moderate net yield of normally solid dissolved coal is conducive to an optimized efficiency for the integrated process. However, it is frequently difficult to perform the process at slurry recycle rates which are sufficiently low to be economically practicable because of a pumpability constraint on the solids level in the feed coal mixing vessel. In the present process, mechanical operability is improved and enhanced conversion of normally solid dissolved coal is achieved by passing a portion of the liquefaction zone product slurry through a hydroclone with the hydroclone overflow stream constituting a second recycle slurry. Deployment of the second recycle slurry accomplishes selective recycle of relatively small particles of mineral residue and tends to reduce the yield of normally solid dissolved coal without resorting to excessive recycle rates, contributing to optimized efficiency for the integrated process.

Integrated coal liquefaction-gasification process

In a coal liquefaction process including recycle to the liquefaction zone of a product slurry containing mineral residue, the minimum slurry recycle rate is determined by a pumpability constraint on the solids level of the slurry contained in the feed coal mixing vessel. If the solids level in the feed coal mixing vessel rises above the constraint level, the slurry recycle rate must increase. For coals which generate a high mineral residue content, adequate dilution of the slurry in the feed coal mixing vessel requires the slurry recycle rate to rise to an economically impracticable level. To avoid a high recycle rate the catalytic advantage of recycle solids is increased by reducing the median diameter of the particles in the recycle slurry stream by passing a portion of the product slurry through a hydroclone to produce a second recycle slurry comprising hydroclone overflow. The process employs a plurality of feed coals, one of which upon dissolution generates smaller and more catalytically active particles of mineral residue than the other. The hydroclone overflow stream selectively concentrates in the recycle slurry the smaller mineral residue particles generated from said feed coal.

Coal liquefaction process with a plurality of feed coals

In a coal liquefaction process which includes a recycle of a product slurry which contain recycle mineral residue and recycle of extraneous catalytic material to said liquefication zone, hydrocracking of the hydrocarbonaceous material from the mineral residue occurs and a mixture of hydrocarbon gases, dissolved liquid, normally solid dissolved coal, suspended mineral residue and suspended extraneous catalytic mineral results. A first portion of said residue slurry is recycled to the liquefication zone, a second portion is passed to separation means and the third portion goes to a hydroclone. Overflow from the hydroclone goes to the liquefaction zone to reduce the median diameter of the particles recycled.

Coal liquefaction process employing extraneous minerals

In a coal liquefaction process including recycle of a product slurry comprising normally solid dissolved coal and mineral residue, the minimum slurry recycle rate is determined by a pumpability constraint on the solids level of the slurry contained in the feed coal mixing vessel. If the solids level in the feed coal mixing vessel rises above the constraint level, the slurry recycle rate must increase. For coals which generate a high mineral residue content, adequate dilution of the slurry in the feed coal mixing vessel requires the slurry recycle rate to rise to an economically impracticable level. In the present process, mechanical operability is improved and enhanced conversion of normally solid dissolved coal is achieved at a given constraint solids level by passing a portion of the liquefaction zone product slurry through a hydroclone with the hydroclone overflow stream constituting a second recycle slurry. Deployment of the second recycle slurry increases the proportion of relatively small more catalytically active particles of mineral residue within the process.

Coal liquefaction process with improved slurry recycle system

In a coupled coal solvent liquefaction-gasification system wherein a recycle mineral residue-containing slurry is mixed with the raw coal feed slurry for the liquefaction zone, the resulting feed slurry is under a pumpability total solids level constraint. Where a coupled system is operating under such a total solids level contraint for the feed slurry, any increase in the mineral residue recycle rate relative to the coal feed rate advantageously provides a catalytic activity and selectivity advantage in favor of liquid coal product at the expense of higher and lower boiling products. It is shown herein that this activity and selectivity effect is enhanced with decreasing liquefaction zone residence times. In accordance with the present invention, the ratio of recycle mineral residue to feed coal is enhanced by recycling a second mineral residue-containing slurry to the liquefaction zone independently of the raw coal feed slurry. The amount of solids in the second recycle slurry can be established to compensate for a progressive reduction in solids level in the process slurry due to the dissolving of feed coal so that the process slurry continues to maintain the maximum total solids constraint in spite of progressive coal solvation.

Coal liquefaction process employing multiple recycle streams

This invention relates to a combination coal liquefaction-gasification process wherein hydrocarbonaceous mineral residue-containing slurry from the liquefaction zone is recycled to the liquefaction zone and all non-recycled hydrocarbonaceous mineral residue-containing slurry is passed to a gasification zone for conversion to synthesis gas to supply hydrogen for the liquefaction zone. It has now been discovered that in this process a surprisingly high reaction selectivity in favor of the desired distillate oil product is achieved by combining low liquefaction zone residence times and relatively high rates of recycle of mineral residue-containing slurry compared to feed coal rate. Under these conditions the yield of the desired distillate oil product can be increased to an unexpectedly high level while the yields of both higher and lower boiling products are each being decreased and while hydrogen consumption is being reduced.

Combined coal liquefaction-gasification process

The rate of separation of suspended mineral particles from a coal liquid is increased by adding a calcium salt, such as calcium carbonate, to the coal liquid. The increase in the separation rate is achieved even though the suspended coal mineral particles naturally contain a calcium salt.

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Allison Park, PA, United States of America

Norman L Carr