600MW机组超净排放技术工程实践及系统优化

Engineering Practice of Ultra-clean Emission Technology for 600MW Unit and System Optimization

为实现600 MW燃煤机组烟气污染物超净排放,某电厂在原有环保设备基础上完成了综合升级改造,内容包括省煤器分级、脱硝催化剂加层、湿法脱硫系统扩容、降低烟气换热器漏风率和新增湿式电除尘器等。针对改造后环保系统运行中存在的问题,研究解决并深度开发,解决了NOx排放质量浓度动态瞬时值超标问题,使其在各种恶劣工况下瞬时值均能小于50 mg/m3,并解决了湿式电除尘器低负荷时水平衡失衡问题,以及完成了脱硝供氨回路冗余改造。实践证明,该电厂的超净排放改造技术路线和系统优化措施均是有效可行的。

In order to realize ultra-clean emission of flue gas pollutant in 600 MW coal-fired unit, comprehensive upgrading and reconstruction is finished on the basis of original environment protection equipments in one power plant, which includes economizer classification, additive layer for catalyst, expansion of wet flue gas desulphurization （WFGD） system, reduction of air leakage rate of gas-gas heater （GGH）, newly addition of wet electrostatic precipitator （WFSP）, and so on. Aiming at existing problems in operation of the environment protection system after reconstruction, this paper carries out research and deep development to solve the problem of dynamic instantaneous over-standard of NOw emission mass concentration and make sure the instantaneous value of NOx emission mass concentration be less than 50 mg/m3 under various bad working con- ditions. It also solves the problem of WESP losing water balance at the time of low load and finishes redundancy modifica- tion for denitration and ammonia-feed loop. Practice proves feasibility of reconstruction technology for ultra-clean emission and measures for system optimization in the power plant.