摘要
为了解决燃煤电站锅炉在中低负荷时,由于SCR入口烟温低于SCR催化剂最佳反应温度范围而导致SCR效率低以及氨逃逸率增加而引起空气预热器的堵灰等问题,以广东某电厂600MW机组锅炉为研究对象,在50%THA、60%THA和70%THA工况下通过热力计算对比分析了4种不同的烟温提升方案,结果表明:给水旁路和省煤器出口水旁路再循环方案调节能力不足,不具备可行性;当所需SCR入口烟温调节幅度在0℃～40℃范围内,省煤器烟气旁路方案有较好的调节能力,但排烟温度会升高,需耦合使用低温省煤器改造等手段消除排烟温度升高带来锅炉效率下降的影响;而省煤器分级改造虽受预留空间及改造费用的影响,但具有明显的烟温调节能力,当移除面积小于原省煤器的50%时,SCR脱硝系统其进口烟温调节幅度在0℃～40℃范围内,又能满足在高负荷下正常运行,且不至于使排烟温度升高,对锅炉运行的经济性不会产生影响。
In order to solve the problems that the SCR denitration efficiency is lower caused by that the SCR inlet flue gas temperature is lower than the best reaction temperature range for the SCR catalyst and the blockage of the air preheater caused by the increase of ammonia slip rate when the coal-fired power plant boiler at low loads,a 600 MW unit in a Guangdong power plant was selected for the study,four different schemes about increasing SCR inlet flue gas temperature were designed and studied at 50%THA,60%THA and 70%THA.By the comparison and calculation for the four kinds of schemes,the conclusion could be drawn:for the scheme of the economizer water-supply bypass and the scheme of the economizer outlet water-bypass recirculation,there was lack of the ability to adjust the SCR inlet flue gas temperature,which is not feasible.When the SCR inlet flue gas temperature adjustment range is 0℃~40℃,the scheme of flue gas-bypass has a good ability to adjust and is satisfied,but exhaust gas temperatureis increased,so the measures such as the low temperature economizer transformation should be taken to eliminate the drop of the boiler efficiency caused by high exhaust flue gas temperature.However,although the scheme of grading-economizer transformation was affected by the reserved space and the cost of the retrofit,the SCR inlet flue gas temperature can be obviously adjusted.When the removal area is less than 50%of the original economizer,the regulation range of the temperature at SCR inlet will be from 0℃to 40℃,which can not only satisfy the normal operation under higher loads,but also not make the flue gas temperature to be increased,which has no effect on the economy of the boiler operation.
作者
廖永进
余岳溪
范军辉
LIAO Yongjin;YU Yuexi;FAN Junhui(Electric Power Science Research Institute of Guangdong Power Grid Co.,Ltd.,Guangzhou 510080,China;School of Energy,Power and Mechanical Engineering,North China Electric Power University, Baoding 071003,China)
出处
《锅炉技术》
北大核心
2018年第5期15-23,共9页
Boiler Technology
基金
南方电网科研项目(K-GD2014-173)
关键词
催化剂
SCR效率
氨逃逸率
SCR入口烟温
优化控制
catalyst
SCR denitration efficiency
ammonia slip rate
SCR inlet flue gastemperature
optimization control
