SNCR∕SCR联合脱硝的应用及对锅炉运行的影响.pdf

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1、SNCR／SCR联合脱硝的应用及对锅炉运行的影响陈镇超(佛山『fj公用事业控股有限公司，广尔佛山52800)摘要：研究了410t／h煤粉炉的SNCR／SCR联合脱硝技术。当NSR为1．5时，NO，浓度从350mg／m3下降到100mg／m3以下，脱硝率约为71．4％，NH，逃逸小于5mL／m3。脱硝率随着负荷的下降呈现上升趋势，NSR的进一步增加对提高脱硝率的意义不大，但是会大量增加NH，逃逸。向炉膛喷射尿素溶液会间接增加冷灰斗水封水的氨味及积灰，此外要避免尿素溶液滴落在水冷壁或喷射到换热器管上从而产生腐蚀。逃逸的NH，促进烟气中硫酸氢铵的生成

2、，加剧空预器的腐蚀，同时还会影响飞灰的品质，与烟气中的HCl等生成NH。CI从而影响GGH的运行，增加烟气PM，；中NH4+离子浓度从而增加烟囱排放的烟羽浊度，形成新的污染，因此要严格控制NH、逃逸并加强空预器、GGH等吹灰措施。关键词：NH、逃逸；脱硝率；冷灰斗；水冷壁；空预器；飞灰；GGH中图分类号：X51l文献标识码：A文章编号：1004—3950(2016)02—0048—08TheapplicationofhybridSNCR／SCRsystemanditseffectontheboileroperationCHENZhen．chao

3、(FoshanPublicUtilitiesHoldingCo．，Ltd，Foshan528000，China)Abstract：ThehybridprocessofSelectiveNon—catalyticReduction(SNCR)followedbySelectiveCatalyticReduction(SCR)wasinvestigatedthroughexperimentationona410t／h，coal—firedutilityboiler．WhenNSRwas1．5，thecon—centrationofNO，decrea

4、sedfrom350mg／m’to100mg／m3．Thedenitrificationefficiencywasabout71．4％andtheNH3slipwaslessthan5mL／m3．Thedenitrificationefficiencyincreasedwiththedroppingload．TheincreaseofNSRtoimprovethedenitrificationratewasnotsignificant，butwouldincreasetheNH3slip．Sprayingureasolutiontothefur

5、nacewouldindirectlyincreaseammoniaodoranddustincoldashbucketofsealwater．Therewasneedtoavoidureasolutiondroppinginwaterwallorsprayingintotheheatexchangertubetoproducecorrosion．NH3slipwouldpromotethegenerationofammoniumsulfateinthefluegasandthecorrosionofairpreheater．Ithadgrea

6、teffectonthequalityofflyashandtheoperationofGGHbecauseoftheformationofNH4CIfromNH3andHCI．Itincreasedtheconcert-trationofNH4+inPM25，thusincreasingthesmokeplumeturbidityandformingnewpollution．TherewasneedtostrictlycontroltheNH3slipandtostrengthenthesoot—blowingonairpreheateran

7、dGGH．Keywords：NH3slip；denitrationefficiency；ashhopper；waterwall；airpre—heater；flyash；GGH0引言为满足越来越严格的氮氧化物(NO，)排放标准，燃煤电厂纷纷采用烟气脱硝技术进行NO，的治理卜2

8、。截至2014年底，全国脱硝装机容量累计达6．87亿kW，占火电总装机容量的75％，占全国煤电机组容量的83．2％，其中97％的脱硝机组采用选择性催化还原技术(SelectiveCatalyticReduction，SCR)。SCR脱硝效率可高达90％，能满足严格的环保排

9、放标准，而选择性非催化还原技术(SelectiveNon-catalyticReduction，SNCR)的效率一般在30％～50％，且脱硝率随着锅炉