Method for co-producing electric power and urea from carbonaceous material

Abstract

A method for co-producing electric power and urea from carbonaceous fuels such as coal, by pyrolizing the coal with oxygen to produce a raw rich gas and a hot char which is gasified with air to produce a raw lean gas. Subsequent to the cleaning of the two gases, the cleaned rich gas is made up of CO and 2H, and the clean lean gas is made up of N+CO. The CO in the rich gas is separated from the 2Hand is added to the lean gas to enrich it with CO to become a lean fuel gas which fuels a gas turbine and is part of a combined cycle system which efficiently generates electric power while exhausting an off-gas (flue gas) made up of N+CO. The 2Hseparated from the CO, and the N+COof the exhausted flue gas are together synthesized to produce urea —CO(NH). To augment the 2Hin order to make the process more efficient, steam is extracted from the power generation system, mixed with the 2H, and electrolyzed in a high-temperature electrolysis system prior to the synthesis step with the electrical energy required for the electrolysis being derived from the combined cycle power generation source. This approach will consume the COin a beneficial manner by co-producing an added-value, useful by-product while at the same time obviating the necessity of collecting COand sequestering it, which is an inefficient way of mitigating the effect of global warming caused by CO.