300MW火电机组低负荷下的脱硝问题和解决方案

Denitrification Problem and Solution for 300MW Coal-Fired Unit with Low Load

以氨气作为催化剂是大型火电机组降低烟气中NOx的常用脱硝方法。此类方法对电站锅炉排烟温度的控制和脱硝装置的投运率产生较大的影响。当排烟温度低于氨气催化温度将造成氨气的逃逸,逃逸的氨气会在空气预热器进口与硫化物反应产生硫酸氢氨晶体,造成空气预热器换热原件的堵塞,影响机组的安全运行并对设备造成一定的损坏。研究探讨大型锅炉安装烟尘脱硝装置后的安全运行,确保机组低负荷下的脱硝投运率和安全运行。

The denitration method using ammonia as catalyst is a common operation method for large thermal power units to reduce NOx in flue gas. However, the exhaust gas temperature has a great influence on the operation rate of denitration device. The exhaust gas temperature lower than the catalytic temperature of ammonia gas will cause ammonia gas to escape. The escaping ammonia gas will react with sulfide at the inlet of the air preheater to generate ammonium bisulfate crystals, causing blockage of the air preheater, affecting the safe operation of the unit and causing certain damage to the equipment. This paper focuses on the safe operation of large boilers after installation of soot denitration devices, and ensures the operation rate and safe operation of denitration under low load conditions.