SCR烟气脱硝系统NO浓度场优化试验研究

Optimization research on the concentration field of NO in Selective Catalytic Reduction flue gas denitrification system

在燃料种类、炉膛结构、受热面布置、过量空气量、炉膛气流分布等条件确定的情况下,控制好喷氨均匀性及氨加入量是保证出口NO浓度场均匀性、脱除率及逃逸氨的关键所在。以某发电厂660MW机组脱硝系统为研究对象,设计了1种控制氨逃逸的优化调整方法,主要根据脱硝系统入、出口NO浓度分布情况调整喷氨系统,以使喷氨分布均匀。优化调整后脱硝系统出口NO浓度场分布均匀性明显改善,出口NO浓度偏差值降低,供氨量和出口氨逃逸平均浓度显著下降。该方法能有效改善脱硝系统出口NO浓度分布,降低喷氨量和氨逃逸浓度。减小SCR脱硝工艺对空气预热器带来的不利影响,在保证NO达标排放的同时,实现安全生产。

In the case of fuel type, furnace structure, heating surface arrangement, excess air volume, furnace gas flow distribution and other conditions are determined, controlling the uniformity of ammonia injection and the amount of ammonia added are The key to ensure the uniformity of the NO concentration field at the outlet, the removal rate and the escape ammonia. Taking 660 MW generator unit denitration system as a study object, an optimization and adjustment method shall be designed to control ammonia slip, i.e. adjust ammonia injection system based on NO concentration distribution at inlet/outlet of the denitration system to make the injected ammonia distribute evenly. After optimization and adjustment, the uniformity of the NO concentration field distribution at the outlet of the denitration system was significantly improved, the deviation of the NO concentration at the outlet was reduced, and the ammonia concentration and the average concentration of the ammonia escaping of the outlet decreased significantly. The results shows that, this method can effectively improve NO concentration distribution at outlet of the denitration system and decrease ammonia injection amount and ammonia slip concentration. Reduce adverse impact of SCR denitration process on the air preheater to realize safe production by guaranteeing that NO discharge shall reach the standard.