Process for gasifying carbonaceous solids and removing toxic constituents from aqueous effluents
AssigneeExxon Research & Engineering Co.
InventorMartin L. Gorbaty
Life of this patent
Estimating the term…
Abstract
Toxic trace element pollutants present in the raw product gas and raw flue gas streams produced during the gasification of coal or similar carbonaceous solids containing sulfur and such trace elements are recovered by separately scrubbing the product gas and flue gas with water, combining the resulting aqueous effluents, and removing the pollutants from the combined aqueous stream as insoluble metal sulfides.
Claims10
In a process wherein a first gas stream containing hydrogen sulfide and a second gas stream having a lower hydrogen sulfide content than said first gas stream and including volatile trace element constituents are produced, the improvement which comprises scrubbing said first gas stream with water to produce a first scrubber water stream containing hydrogen sulfide removed from said first gas stream, scrubbing said second gas stream with water to produce a second scrubber water stream containing trace element constituents removed from said second gas stream, combining said first scrubber water stream and said second scrubber water stream to produce a combined scrubber water stream, stripping gases from said combined scrubber water stream to produce an aqueous stripper effluent, and thereafter removing precipitated solids from said aqueous stripper effluent.
In a gasification process wherein a solid carbonaceous feed material is reacted with steam to produce a raw product gas containing methane, hydrogen, carbon monoxide, carbon dioxide, and hydrogen sulfide and wherein heat is generated by the combustion of carbonaceous solids to produce a raw flue gas having a lower hydrogen sulfide content than said raw product gas and including volatile toxic trace element constituents, the improvement which comprises scrubbing said raw product gas with water to produce a product gas scrubber water stream containing hydrogen sulfide removed from said product gas, scrubbing said raw flue gas with water to produce a flue gas scrubber water stream containing toxic trace element constituents removed from said flue gas, combining said product gas scrubber water stream and said flue gas scrubber water stream to produce a combined scrubber water stream, stripping gases from said combined scrubber water stream to produce an aqueous stripper effluent, and thereafter removing precipitated trace element sulfides from said aqueous stripper effluent.
Dependencies are inferred from the claim text.