摘要
某公司2台330 MW火电机组,配套SG-1151/17.5-M4008型亚临界、自然循环汽包锅炉,同步设置SCR脱硝装置。因系统智能化水平有限,烟气NO_(x)测量及控制滞后。在超低排放改造、燃用非设计煤种、深度调峰等工况下,燃烧波动频繁,SCR入口NO_(x)快速升高且波动剧烈,需喷入过量氨气抑制出口NO_(x)波动。这就导致氨逃逸率升高,生成硫酸氢氨等有害物质,造成空预器堵塞、电除尘效率降低、脱硝催化剂寿命缩短,且逃逸氨使脱硫外排水氨氮超标。深度调峰模式下,低负荷段烟温低、流场变化大,此问题更易发生且危害更大。通过优化脱硝烟气流场、NO_(x)测量及闭环控制系统,可精准控制喷氨量,改善氨逃逸问题,节能效果显著,对同类机组具有推广价值。
At a power plant,two 330 MW coal-fired units are equipped with SG-1151/17.5-M4008 subcritical,natural circulation drum boilers and synchronous SCR(selective catalytic reduction)DeNO_(x) systems.Due to limitations in system intelligence,there is a lag in flue gas NO_(x) measurement and control.Under operating conditions such as ultra-low emission retrofits,burning non-design coal types,and deep peak regulation,frequent combustion fluctuations cause SCR inlet NO_(x) levels to rise rapidly and fluctuate violently.This necessitates injecting excessive ammonia to suppress outlet NO_(x) fluctuations.Consequently,the ammonia slip rate increases,leading to the formation of harmful substances like ammonium bisulfate.This results in air preheater clogging,reduced electrostatic precipitator efficiency,shortened DeNO_(x) catalyst lifespan,and excessive ammonia nitrogen levels in the desulfurization wastewater discharge due to escaped ammonia.During deep peak regulation modes,particularly at low loads,lower flue gas temperatures and significant flow field changes make this problem more prone to occur and its consequences more severe.Optimizing the DeNO_(x) flue gas flow field,NO_(x) measurement,and closed-loop control system enables precise control of ammonia injection,effectively mitigating ammonia slip issues.This approach yields significant energy savings and holds reference value for similar units.
作者
张巍
ZHANG Wei(Sinopec Great Wall Energy Chemical(Ningxia)Co.,Ltd.Thermal Power Operation Department,Lingwu 750411,China)
出处
《化工管理》
2025年第27期136-139,共4页
Chemical Management
关键词
锅炉
脱硝
喷氨
催化剂
氨逃逸率
堵塞
boiler
DeNO_(x)
ammonia injection
catalyst
ammonia slip rate
clogging
