Exxon Research and Engineering Company

Other

Robert D Wesselhoft

Charles J Vadovic

Daniel Francis Ryan

Nicholas Charles Nahas

Charles A Euker, Jr

John J Dunkleman

Dolores C Aquino

Toby R Gouker

Coal or similar carbonaceous solids impregnated with gasification catalyst constituents (16) are oxidized by contact with a gas containing between 2 volume percent and 21 volume percent oxygen at a temperature between 50.degree. C. and 250.degree. C. in an oxidation zone (24) and the resultant oxidized, catalyst impregnated solids are then gasified in a fluidized bed gasification zone (44) at an elevated pressure. The oxidation of the catalyst impregnated solids under these conditions insures that the bed density in the fluidized bed gasification zone will be relatively high even though the solids are gasified at elevated pressure and temperature.

Fluidized bed catalytic coal gasification process

Hydrocarbon liquids and a methane-containing gas are produced from carbonaceous feed solids by contacting the solids with a mixture of gases containing carbon monoxide and hydrogen in a devolatilization zone at a relatively low temperature in the presence of a carbon-alkali metal catalyst. The devolatilization zone effluent is treated to condense out hydrocarbon liquids and at least a portion of the remaining methane-rich gas is steam reformed to produce the carbon monoxide and hydrogen with which the carbonaceous feed solids are contacted in the devolatilization zone. The char produced in the devolatilization zone is reacted with steam in a gasification zone under gasification conditions in the presence of a carbon-alkali metal catalyst and the resultant raw product gas is treated to recover a methane-containing gas.

Integrated catalytic coal devolatilization and steam gasification process

In a coal gasification operation or similar process carried out in the presence of an alkali metal-containing catalyst wherein spent solids containing ash and alkali metal catalyst residues are produced, alkali metal constituents are recovered from the spent solids by first removing magnetic constituents from the solids, contacting the solid particles from which magnetic constituents have been separated with an acid solution to extract alkali metal constituents from the solids and produce a spent acid solution enriched in alkali metal salts, raising the pH of the enriched solution sufficiently to precipitate aluminum from the solution as aluminum hydroxide, heating the remaining solution to precipitate silicon compounds, and recovering an enriched alkali metal solution from which aluminum and silicon compounds have been removed. This process permits the effective recovery of alkali metal catalyst constituents, eliminates iron compounds and other inactive constituents which may otherwise tend to build up in the catalyst system, and makes possible the recovery of aluminum as a valuable by-product of the process.

Alkali metal catalyst recovery system

A water-soluble alkali metal compound or other soluble constituent is recovered from a mixture of solid particles of different densities and the solid particles are simultaneously separated into two fractions, one having a greater density than the other by countercurrently contacting the solids with a leaching agent in which said constituent is soluble in a countercurrent multistage leaching system, maintaining the density of the enriched leaching agent in the final stage of the system at a value intermediate the densities of the particles in the mixture, and separately recovering enriched leaching solution, particles having a density greater than that of the enriched leaching solution, and particles with a density less than that of the enriched solution from the system. The process is particularly useful for the recovery of alkali metal constituents used to catalyze the gasification of coal and other carbonaceous solids.

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Robert D Wesselhoft