Techno-economic Analysis Of600MW Air Enrichment Pulverized-coal Fired Boiler

Oxy-fuel combustion of fossil fuel is one of the most promising methods to produce a stream of concentrated CO2ready for sequestration. However, equipment for huge oxygen production and extra energy that usually leads to the decreasing for the efficiency of power generation and economics. For exploring a CO2emission-reduction technology with better economy in thermal power plant, a new "air enrichment" process was suggested in this study, which allows air to be partially used in the oxy-fired coal power plants. Under air enrichment, CO2concentration in flue gases is30%-40%, and PSA(Pressure Swing Adsorption) technology is used for CO2removal from flue gases.Take a600MW pulverized coal boiler as example, the component of flue gases and theoretical combustion temperature in furnace were studied under dry/wet cycle of oxy-fuel and air enrichment modes; Based on energy balance, convective and radiant heating surface are redesigned. The emissivities for tri-atom gases have already studied by radiant model of Soviet Union and the benchmark models under dry/wet cycle of oxy-fuel and air enrichment modes. Techn-economy analysis for air enrichment with PSA was done, and the results were compared with of oxy-fuel. Based on energy matched, the design of a600MW boiler were done under oxy-fuel combustion and air enrichment respectively.Compared with oxy-fuel, the investment and energy consumption for ASU(air seperation unit) and circulation fan were decreased because of the decreasing of pure oxygen and recycled flue gases under air enrichment, which provides the potential for improving economy. Considering the revenue from CO2sale, when the volume ratio of air and oxygen up to2-3, the economy of air enrichment with PSA is obvious better than that of oxy-fuel combustion in CO2emissions reduction application. Under air enrichment, the modifications on the original boiler structure are smaller than that under oxy-fuel combustion.