Abstract:At present, Guizhou thermal power plant mainly burns high sulfur and high ash coal, mainly uses SCR denitrification technology, and a few power plants use SCR + SNCR denitrification technology. In the actual operation process, there are problems such as ash deposit in flue gas system, blockage of air preheater, damage of denitrification catalyst, which bring many hidden dangers to normal production and operation, and affect the machine. Group safety and economic operation. In order to solve the problems in the operation of SCR denitrification technology in Guizhou Province in recent years, this paper analyzes the causes of ammonia escape and ammonia bisulfate blockage in the flue gas environment with high sulfur and ash content. Through summing up the experience of denitrification control system in Guizhou thermal power plants in recent years, the paper points out that the key to denitrification in thermal power plants is to reduce the consumption of denitrification ammonia by adjusting the uniformity of flue gas field and ammonia spraying. It also puts forward the methods of catalyst management and maintenance of thermal control elements. During the long term operation of the boiler, measures such as improving the comprehensive temperature of the cold end, flushing the air preheater and thermal decomposition can be adopted.