氨煤混燃NO生成机理研究

Study on NO formation mechanism of ammonia-coal co-combustion

以氨煤混燃为研究对象,研究了不同温度,不同掺氨比(氨气完全燃烧释放的热量在总热量中所占百分比)对NO生成特性的影响。研究结果表明:温度与掺氨比对NO体积分数有显著的影响,在温度为1000℃和1100℃工况下,氨气的加入会抑制NO的生成;随着温度的升高,氨燃烧性能增强,促进了燃料-N到NO生成,使得温度在1200℃时,NO生成量随着掺氨比的增加而增大;当温度进一步升高至1300℃以上时,未燃氨协同煤焦对NO的还原作用增强,表现为NO生成量随掺氨比的增加呈现先增加后降低的规律;温度在1200℃时,单位质量燃料的NO释放量随着掺氨比的增加而增加;在研究的其他温度区间中,单位质量燃料的NO释放量随着掺氨比的增加而减少;煤粉燃烧中掺入氨气会大幅度降低燃料-N到NO的转化率,不同温度和不同掺氨比对燃料-N到NO转化率的影响不同。

The effects of different temperatures and ammonia doping ratios(the percentage of heat released by complete combustion of ammonia in the total heat)on the NO generation characteristics were studied for the ammonia coal co-combustion.The results show that the temperature and ammonia doping ratio have a significant effect on the NO concentration,and the addition of ammonia suppresses NO formation under the operating conditions of 1000℃and 1100℃.With the increase of temperature,the combustion performance of ammonia is enhanced and the fuel-N to NO generation is promoted,resulting in the increase of NO formation with the increase of ammonia doping ratio at 1200℃.When the temperature is further increased to more than 1300℃,the reduction effect of unburned ammonia and char on NO is enhanced,showing that NO increases first and then decreases with the increase of the ammonia doping ratio.The NO release per unit mass of fuel increases with the increase of the ammonia doping ratio at the temperature of 1200℃.In the other temperature intervals studied,NO release per unit mass of fuel decreases with increasing ammonia doping ratio.The addition of ammonia to pulverized coal combustion will drastically reduce the conversion of fuel-N to NO,and different temperatures and different ammonia ratios have different effects on the conversion of fuel-N to NO.