Catalytic Gasification Process with Recovery of Alkali Metal from Char
AssigneeGreatpoint Energy, Inc.
InventorsAlkis S. Rappas, Robert A. Spitz
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Abstract
Processes for extracting and recycling alkali metal compounds present in the char produced from the catalytic gasification of carbonaceous materials are provided involving at least contacting the char with and alkali metal hydroxide followed by carbon dioxide. Both the alkali metal hydroxide and carbon dioxide treatments serve to convert at least a portion of the insoluble alkali metal compounds in the char into soluble species which can be recovered and recycled.
Claims13
A process for extracting and recovering alkali metal from a char, the char comprising (i) one or more soluble alkali metal compounds and (ii) insoluble matter comprising one or more insoluble alkali metal compounds, the process comprising the steps of:
- (a) providing the char at an elevated temperature ranging from 50° C. to about 600° C.;
- (b) quenching the char in an aqueous medium to fracture the char and form a quenched char slurry;
- (c) contacting the quenched char slurry with an alkali metal hydroxide under suitable pressure and temperature so as to convert at least a portion of the insoluble alkali metal compounds to one or more soluble alkali metal compounds, and produce a first leached slurry comprising the soluble alkali metal compounds and a partially extracted insoluble matter;
- (d) contacting the first leached slurry with carbon dioxide under suitable pressure and temperature so as to convert at least a portion of the insoluble alkali metal compounds to one or more soluble alkali metal compounds, and produce a second leached slurry comprising the soluble alkali metal compounds and a residual insoluble matter;
- (e) degassing the second leached slurry under suitable pressure and temperature so as to remove a substantial portion of the excess carbon dioxide and hydrogen sulfide, if present, and produce a degassed second leached slurry;
- (f) separating the degassed second leached slurry into a first liquid stream and a residual insoluble matter stream, the first liquid stream comprising a predominant portion of the soluble alkali metal compounds from the degassed second leached slurry, and the residual insoluble matter stream comprising residual soluble alkali metal compounds and residual insoluble alkali metal compounds;
- (g) recovering the first liquid stream;
- and
- (h) washing the residual insoluble matter stream with an aqueous medium to produce a first wash stream comprising substantially all of the residual soluble alkali metal compounds from the residual insoluble matter stream,
- wherein the quenching and contacting is performed in the substantial absence of gaseous oxygen.
Dependencies are inferred from the claim text.