600MW机组SCR烟气脱硝系统性能分析与诊断

Performance Analysis and Diagnosis of SCR Flue Gas Denitrification System on 600 MW Unit

某火电厂600 MW机组SCR烟气脱硝系统通过增加喷氨量,使SCR反应器出口NO_x排放质量浓度降至50 mg/m3以下,但由于SCR烟气脱硝系统喷氨量过大、NO_x与氨混合的均匀度不足、烟气流速超过设计值、氨逃逸监测表计不准确等原因,环保系统出现了电除尘器二次电流下降、布袋除尘器阻力增加、SCR反应器出口烟道处与烟囱入口处的NO_x质量浓度存在偏差等问题。通过调整喷氨量和各喷氨阀门的开度,提高了NO_x与氨混合的均匀度,消除了NO_x质量浓度偏差,并就具体问题给出了相应的建议。

In order to make the SCR reactor outlet NOx emissions of emission concentration decreased to 50 mg/m3 below in a thermal power plant, increased the amount of ammonia injection. However, the SCR flue gas removal denitrification system of ammonia injection amount was too large, SCR system of NOx and ammonia mixed lack of uniformity, flue gas velocity more than design value, ammonia escape monitoring meter was not accurate and other reasons, ESP secondary current decline, bag dust collector resistance increased, SCR reactor outlet flue and chimney at the entrance of the NOx concentration deviation problem. Through adjust the spray amount of ammonia and the spray ammonia valve opening, solved the issues related to environmental protection system and improved the evenness of NOx and NH3 mixing, eliminated the NOx concentration deviation, and to the specific problems, gave corresponding suggestions.