Coupling combustion technology of gas turbines flue gas and coal-fired boiler
To effectively utilize the exhaust heat of gas turbines,the feasibility of coupling combustion technology of coal-fired boilers and gas turbines flue gas was explored.Based on the basic theory of combustion,detailed calculations were conducted on the theoretical air volume,flue gas volume,burner nozzle velocity and other parameters of coal-fired boiler combustion after mixing with gas turbine flue gas.A coupling combustion technology scheme of gas turbine flue gas and coal-fired boiler was proposed.The influence of flue gas coupling on the combustion characteristics of coal-fired boiler was analyzed using full-scale numerical simulation technology.The nu-merical simulation results indicate that after flue gas coupling,the tangential diameter increases.As the initial temperature of pulver-ized coal flow increases,the volatile releases earlier,and the pulverized coal ignites earlier,the temperature of the boiler furnace decrea-ses,and the heat absorption of the water wall decreases.The NOx emission at the furnace outlet increases from 222.1 mg/m3 to 229.5 mg/m3,and the burnout rate decreases from 98.91%to 96.9%.Based on numerical simulation results,the energy consumption of the whole plant after flue gas coupling was analyzed,it can be concluded that although the coal consumption of boiler power generation in-creases by 2.0 g/kWh,the waste heat utilization efficiency of gas turbine flue gas has increased from about 80%to about 93%,represen-ting a reduction of 10.98 g/kWh in the coal consumption of boiler power generation,so the energy consumption of the whole plant has de-creased.The results indicate that coupling combustion technology of coal-fired boilers and gas turbines is feasible.After flue gas coupling,the gas turbine flue gas replaces most of the secondary air,significantly reducing the air flow through the air preheater,resulting in a sig-nificant decrease in the heat of the air preheater and a significant increase in the flue gas temperature.It is necessary to add a waste heat utilization device after the air preheater.
gas turbines flue gascoal-fired boilercouplingcombustion characteristicswaste heat efficiency
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