Simulation Study on the Co-Combustion of Semi-Coke and Ammonia Under Different Blending Methods

In this study，a 300 kW pilot-scale pulverized coal combustion system was taken as the research object，and the effects of blending methods and blending ratios on the co-combustion characteristics of semi-coke and ammonia were investigated by numerical simulation. The results show that the addition of ammonia promotes the ignition of semi-coke and changes the combustion process from two stages to three stages under both in-furnace and out-furnace mixing methods. When the ammonia blending ratio is 25% and 50%，the ignition distance in the furnace is shorter，and the trend is opposite when the blending ratio is increased to 75%. With the increase of ammonia blending ratio，the NO emissions under the two blending methods show a downward trend，and the NO emissions under the in-furnace blending method are always lower than those under the out-furnace blending combustion. Therefore，it is recommended that the proportion of ammonia in semi-coke should not exceed 50%，and the in-furnace blending method is more suitable for the co-combustion of semi-coke and ammonia.