0.3 MW循环流化床燃煤锅炉SO_3脱除试验研究  

Experimental study on SO_3 removal for a 0.3 MW circulating fluidized bed coal-fired boiler

作　　者：杨钊[1] 黄亚继[1] 黄学希 季学勤 董璐[1] 王芳勇 郭学敏 

机构地区：[1]东南大学能源热转换及其过程测控教育部重点实验室,江苏南京210096 [2]芜湖发电有限责任公司,安徽芜湖241009 [3]南京开拓环保科技有限公司,江苏南京210019

出　　处：《热力发电》2018年第3期62-67,共6页Thermal Power Generation

基　　金：国家自然科学基金项目(51476031);江苏省重点研发计划项目(SBE2017030722)~~

摘　　要：燃煤电厂选择性催化还原(SCR)脱硝系统中SO_3与NH3生成的硫酸氢铵在低温下冷凝沉积是限制脱硝温度窗口的主要原因,且SO_3还易导致锅炉尾部设备低温腐蚀、堵灰。对此,本文在自行设计及搭建的0.3 MW循环流化床燃煤锅炉中试台上,采用在SCR脱硝系统前喷射Na_2CO_3溶液的方式,研究中低温条件下,喷射Na_2CO_3溶液对SO_3和NOx脱除效果的影响,探究此方法实现燃煤电厂低负荷脱硝同时满足国家NOx排放标准的可行性。结果表明:采用SCR脱硝系统前喷射Na_2CO_3溶液方式时,SO_3脱除效率随Na_2CO_3/SO_3摩尔比的增大而升高,增长趋势减缓;SCR脱硝反应器前喷射Na_2CO_3溶液并不会因为SO2的存在而影响Na_2CO_3溶液对SO_3的脱除效果;在SCR脱硝系统前喷射Na_2CO_3溶液不会对脱硝造成显著影响;此外,280℃下采用SCR脱硝系统前喷射Na_2CO_3溶液的方式,能够提高低温脱硝效率。该结论为锅炉低负荷脱硝提供了试验数据。Condensation of ammonium bisulfate produced by SO3 and NH3 in the SCR denitration system at low temperature is the main reason for limiting the denitration temperature window of coal-fired power plants. At the same time, SO3 is also the source of low temperature corrosion on the boiler tail equipments and ash clogging. To solve this problem, the self-built 0.3 MW circulating fluidized bed boiler （pilot scale） was applied to carry out pollutant removal test by spraying Na2CO3 solution before the SCR denitration system at medium and low temperatures. The effect of spraying Na2CO3 solution on removal of SO3 and NOx were studied. On this basis, this method was explored to broaden the denitration temperature window to achieve low load denitration for coal-fired power plants and to meet the national NOx emission standards. The results show that, the removal efficiency of SO3 increased with the molar ratio of Na2CO3 to SO3 , and the growth rate decreased gradually. Spraying Na2CO3 solution before the SCR reactor didn＇t affect the removal effect of SO3 due to the presence of SO2, and didn＇t significantly affect the denitration, either. In addition, the low temperature denitration experiment at 280 ℃ shows that the denitration efficiency can be improved by spraying the Na2CO3 solution before the SCR reactor. This conclusion can provide a reference for low load denitration.

关 键 词：SO3脱除 Na2CO3溶液 SO2 低温腐蚀 脱硝催化剂 低温脱硝 SCR脱硝 

分 类 号：X701[环境科学与工程—环境工程]