Meteorological and Environmental Research 2014,5(7):31—33 Editor.Yang Yingying Proofreader:Yang Yingying Comprehensive Solution to Flue Gas DeSUlfurizatiOn and Denitration of Circulating Fluidized Bed Boiler Wang Jianchun’, ’ 1.Fujian Longking Co.,Lld.,Longyan 364000,China;2.Lonjing Environment Technology Co.,Lfd.,Xiamen 361009,China Abstract With the advantagas of high combustion efficiency。wide rueI1lexibility and Iow concentrations of discharged pollutants,circulating fluid- ized bed(CFB)boiler has been widely used in racent years.However,in order to meet the requirement of new emission standard,it's necessary to add flue gas desulfurization and denitration devices.In this paper,the choice of flue gas purification processes for C:FB boiler has been discussed firstly.and then the economy and rationality of the SNCR+CFB-FGD+COA comprehensive solution to flue gas desulfurization and denitr ̄ion have been analyzed. Key words CFB boiler;Flue gas;Desulfurization;Denitration;SNCR+CFB—FGD+COA:China ln China.a major coal producer and user.cooI accounts for about 70%in the primary energy structure.and sulfur con- tem in 25%of coaI exceeds 2%.so that a Iarge quantity of Table1 Limitation for air pollutants in the Emission Standardof Air Pollutants for Thermal Power Plants f GB 13223- 2011)_4_ SO2 and NO are discharged into the atmosphere every year due to coaI combustion.thereby Ieading to serious environmen- taI pollution.Therefore.developing clean combustion technolo- gY with high efficiency and low pollution is the necessary re- quirement for sustainable development of modern societY. Circulating fluidized bed(CFB)boiler is an efficient clean combustion technology that has developed rapidly in recent years.With the advantages of high combustion efficiency.wide fuel flexibility,Iow concentrations of discharged pollutants, etc.。CFB boiler has been developed rapidly on a large scale jn the context of increasingly serious energy shodage and envi- ronmentaI protection requirements nowadays。 2 Choice of flue gas purification proces・ 1 Discharge situation of pollutants from CFB boiler has characteristics of desuIfurjzatjOn jn the ses for CFB boiler 2.1 Desulfurization process Limestone can be added to CFB boiler boiler and staged combustion,and SO,and NO emissions can be controlled at a Iower leve1 without any accessory equip- ments….CFB boiler to realize SO,removal,so that SO,emission is Iow- er than 4OO mg/m .However,SO removaIin the boiler can not meet the requirement of new nationaI emission standard. especially for boilers with inferior high-sulfur and Iow-heat-value fuels such as coal washery sludge,cool gangue,oil shale and petroleum coke,so it's necessary to add flue gas purification system.1f SO removaI efficiency of CFB boiler reaches above SO,and NO emissions are below 400 and 200— 300 mg/Nm。respectively.However,it is dificult for CFB boil- er to meet the requirement of new nationaI emission standard in the“1 2 Five—year Plan”period(Table 1),so it's impera- rive to add flue gas desulfurization and denitration systems 80%。the ratio of Ca to S(Ca/S)is 2.0—2.5.Therefore.flue gas discharged fr0m CFB boiler contains 50%of unreacted CaO.The CFB-FGD process can make the unreacted CaO downstream the boiler  ̄3j. transf0rm into Ca(OH)2 rapidly in the absorber to remove SO, Received:June 10,2014 Accepted:July 3.2014 again.This process can not only make CFB boiler with inferior fuels meet environmentaI requirements.but also reduce operat- ing cost greatly 。-uj. 2.2 Denitration process At present.flue gas denitration is SuppoSed by the National High Technology Reseamh and Develop- ment Program of China(863 Program)(201 3AAO65403);Major Sci- ence and Technology Project of Fujian Province. China (201 1 HZOO05-1):InternationaI Science and Technology Cooperation Program(2010DFB93990):Natural Science Foundation of Fujian Province.China(201 4J06020). realized mainly using selective catlytaic reduction(SCR)and selective non・catalytic reduction(SNCR) 一’0J.1n comparison th SNCR,denitr ̄ion efficiency of SCR is higher,but it is not suitable for CFB boiler to adopt SCR due to the follow-uD rea- {Corresponding author.E—mail:wangjianchun@Ionjing.com Wang Jianchun.Comprehensive Solution to Flue Gas Desulfurization and Denitration of Circulating Fluidized Bed Boiler 2Ca(OH)2+2HCI— +CaCI2+・Ca(OH)2・2H2O Ca(OH),+2HF_++CaF,+2H,O Afterwards.the purified flue gas goes through the fabric f¨一 ter to separate solids fr0m gas.and then the gas enters the forth.SNCR denitration process has become the preferred prcess foro flue gas denitration of CFB boiler. The flue gas purification system SNCR+CFB.FGD-i-COA proposed according to characteristics of flue gas of CFB boiler has high desulfurization and denffration efficiency.sO it is an ef. fective comprehensive solution to flue gas desulfurization and denitration. stack.Most solid particles raturns to the absorber through the recirculating system.while the left ash is transported into the by・-product silo and then discharged through a tanker or sec・- onda ̄transportation. 3.2 CharacterlstIcs of SNCR+CFB-FGD+COA system Flue gas desulfurization and denitration processes are integrat- ed into the flue gas purification system SNCR+CFB—FGD+ COA,and the systern has many advantages.First,the system is simple with small investment.Secondly.it occupies a smalI space and is suitable for flue gas purification of sinaiI and mid- die plants.Thirdly.flue gas desulfurization and denitration would not interfere with each other.and operating parameters [1]LIU F,GUO J。Analysis on desulfurization technology of circulating lfuidized bed boiler[J].Zhongzhou Coal,20ee(5):54—56.(in Chi・ nese). 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