石炭ガス化中カロリー燃料用ガスタービン燃焼器 : 第2報,希薄燃焼によるNOx低減強化型燃焼器の高圧燃焼特性(熱工学,内燃機関,動力など)

The "integrated coal gasification combined cycle" (IGCC) requires the development of a gas turbine combustion technology using gasified coal fuel, which has high thermal efficiency and low NOx emission. Medium-Btu fuel produced in an oxygen-blown coal gasifier has a calorific value of 9-13 MJ/m3, which is around one fifth that of natural gas. However, the flame temperature of medium-Btu fuel is higher than that of natural gas and so NOx emission is expected to increase significantly. Moreover, flame temperature rises in proportion to the rise in a calorific value of medium-Btu fuel. We have developed a combustion method with nitrogen injection, which is produced in the air-separation unit, and lean combustion, designed mainly for achieving low NOx emission and stable combustion. Under operational conditions, NOx emission is reduced significantly, while flame stability maintained. In this report, we will clarify the influence of pressure on the NOx emission in the medium-Btu fueled combustion, propose the low NOx combustion technology for gasified coal fuel, and provide useful engineering guidelines for the development of the gas turbine combustor.