In order to investigate the influence of temperature on combustion process of biomass gas mixed with pulverized coal

the co-firing models were built using the Fluent software.By taking a subcritical 300 MW unit boiler as the object

the combustion processes under different conditions were simulated

the velocity field

temperature field

flue gas components and the NO_x distribution features in the furnace were numerically analyzed.The four conditions were pure pulverized coal combustion case and three co-firing cases with 10% biomass gas at 300 ℃

450 ℃ and 600 ℃.The results show that

compared with pure coal combustion condition

during the cocombustion process

the outlet biomass gas velocity at lower burner increases

the temperature at the furnace center decreases

the O_2 and CO volume fraction at furnace outlet increases while the CO_2 and NO decreases.The mass concentration of NO_x decreases by 15%

24% and 32% with the increasing biomass gas temperature.