Patent ID: 8084010
Filing Date: 2011-12-27
Classification: C01B,C01D,F23C,F23J,F23L,Y02E

Abstract:
1. A method of operating a coal/coke/heavy residual oil steam boiler to produce an exiting carbonaceous flue gas containing predominantly carbon dioxide with low nitrogen oxide, sulfur oxide and water concentrations, the method comprising: (a) admixing a carbon-based fuel with an alkali metal compound; (b) combusting the carbon-based fuel with a 95-100 percent pure oxygen stream and a flue gas recirculation stream, the recirculation stream containing predominately carbon dioxide; and (c) varying the mass flow ratios of the oxygen and recirculation streams such that a desired boiler temperature profile, a reduction in sulfur oxide concentration in said exiting carbonaceous flue gas to a concentration of less than 50 parts per million and a reduction in nitrogen oxide concentration in said exiting carbonaceous flue gas to a concentration of less than 100 parts per million is achieved.