CH_4/O_2/H_2O燃气轮机富氧燃烧特性

Oxy-Fuel Combustion Characteristic of CH_4/O_2/H_2O in Gas Turbine

使用Chemkin—Pro对CH4富氧燃烧特性（层流火焰传播速度、自点火延迟时间、化学反应特征时间及污染物的排放）在典型燃气轮机运行条件下进行了计算．计算采用GRI—Mech3．0详细化学反应机理，包括53种组分，325个基元反应．结果表明，对于带有碳捕集的系统，当量比增加2％，便可以使得排气中氧气浓度下降50％；设计CH4／空气所用的自点火延迟时间的经验或准则也同样适用于CH4／02／H20；当CH4／02／H20中氧气的体积分数为26％～27％时，富氧燃烧室的回火、吹熄以及出口温度特性与以CH4／空气为燃料的燃气轮机最接近，此时对原型燃烧室的结构改动最少．

Laminar flame speed, ignition delay time, chemical characteristic time and pollution emission of CH4/O2/H20 in typical gas turbine condition were calculated by Chemkin-Pro. A detailed reaction mechanism GRI- Mech 3.0, which includes 53 species and 325 elemental reactions were used. The following conclusions are drawn： with CO2 capture system, the 02 concentration in exhaust gas is reduced 50% while the equivalence ratio increases by only 2%; the experiential rules for auto-ignition of CH4 and air mixture are also suitable for CH4/O2/H20; when the 02 volume fraction in mixture CH4/O2/H20 remains about 26%--27%, flashback, blow-off and temperature charac-teristic at outlet of oxy-fuel combustion combustor are nearly the same as those of CH4/air gas turbine, and then the modification of original combustor is the least.