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

• Main Author: CALDERON ALBERT
• Format: Patent
• Language: English
• Published: 31.08.2010
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; AIR INTAKES FOR JET-PROPULSION PLANTS; BLASTING; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; COMBUSTION ENGINES; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; DYNAMO-ELECTRIC MACHINES; ELECTRICITY; GAS-TURBINE PLANTS; GENERATION; HEATING; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS; LIGHTING; MECHANICAL ENGINEERING; METALLURGY; ORGANIC CHEMISTRY; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; THEIR RELEVANT APPARATUS; TRANSPORTING; WEAPONS

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 2H2, and the clean lean gas is made up of N2+CO. The CO in the rich gas is separated from the 2H2 and 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 N2+CO2. The 2H2 separated from the CO, and the N2+CO2 of the exhausted flue gas are together synthesized to produce urea -CO(NH2)2. To augment the 2H2 in order to make the process more efficient, steam is extracted from the power generation system, mixed with the 2H2, 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 CO2 in a beneficial manner by co-producing an added-value, useful by-product while at the same time obviating the necessity of collecting CO2 and sequestering it, which is an inefficient way of mitigating the effect of global warming caused by CO2.