循环流化床锅炉中SNCR系统控制流程的探讨

The discussion of the control process of the SNCR system in the CFB boiler

为了降低氮氧化物的排放,循环流化床锅炉中通常采用SNCR脱硝系统,利用还原剂将烟气中的氮氧化物还原为无污染的氮气。SNCR脱硝系统的喷枪通常设置在分离器入口烟道,为了确保脱硝效率,须使还原剂与烟气充分混合。本文主要从按分离器为单元和按每层喷枪为单元,对循环流化床锅炉中SNCR系统控制流程进行分析,从系统的复杂程度与可靠性来对比两种控制流程的优缺点。

For the sake of the decrease of NO_x,SNCR denitration system which uses reducing agent to change NO_x in the flue gas to pollution-free N_2 is usually adopted in the Circulating fluidized bed boiler.The spray lances of the SNCR denitration system are usually arranged in the inlet flue ducts of the cyclones where the reducing agent can be well mixed with the flue gas in order to ensure the denitration efficiency.This paper analysis the control process of the SNCR denitration system in the Circulating fluidized bed boiler according to the unit of per cyclone and the unit of per layer spray lances,and compares the advantages and disadvantages of two kinds of the control process from the complexity and reliability of the system.