煤粉炉和循环流化床锅炉飞灰特性对其汞吸附能力的影响
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摘要
通过分析两台容量相近的循环流化床锅炉和煤粉锅炉飞灰样品的粒径分布、表面结构特性、未燃尽碳含量、反应性和汞含量,探究两种类型锅炉飞灰特性差异及其与飞灰汞吸附能力的关系。结果表明:循环流化床和煤粉锅炉尾端除尘设备排灰口飞灰汞的含量分别为1584.0 ng/g和503.7 ng/g,其原因与飞灰粒径、未燃尽碳含量和表面特性相关。对于循环流化床锅炉,飞灰中汞含量随其粒径和反应性温度的减小而增加,随未燃尽碳含量增加而增加,且与比表面积和吸附量呈正相关关系。对于煤粉锅炉,粒径为75～53μm的飞灰对汞吸附能力较强,未燃尽碳含量明显小于循环流化床所产生飞灰的含量,飞灰比表面积随粒径变化不大,由此导致煤粉锅炉除尘设备排灰口所取样品对汞的吸附能力远低于循环流化床锅炉相对应位置飞灰对汞的吸附能力。
The particle size distribution, surface structure property, unburned carbon content and mercury content of fly ash were investigated to understand the effect of boiler type and mercury adsorption capability on fly ash.Different samples were obtained from a circulating-fluidized bed(CFB) boiler and a pulverized coal(PC) boiler with the capacity of around 300 MW coal-fired power generation units. In this study, the mercury contents in fly ash collected from the CFB and PC boilers are 1584.0 ng/g and 503.7 ng/g, respectively. The results show that the mercury content in the fly ash from CFB boiler increases with decreasing particle size and reactivity temperature,but increasing surface area and unburned carbon content. For the fly ash from PC boiler, the portion with the diameter of 75-53 μm displays better mercury adsorption capability, the unburned carbon content is much lower than that from CFB boiler, and the surface area is almost independent to particle size. As a result, the adsorption capacity of the sample taken from the ash discharge port of the pulverized coal boiler dust removal equipment is much lower than that of the corresponding position of the circulating fluidized bed boiler.
The particle size distribution, surface structure property, unburned carbon content and mercury content of fly ash were investigated to understand the effect of boiler type and mercury adsorption capability on fly ash.Different samples were obtained from a circulating-fluidized bed(CFB) boiler and a pulverized coal(PC) boiler with the capacity of around 300 MW coal-fired power generation units. In this study, the mercury contents in fly ash collected from the CFB and PC boilers are 1584.0 ng/g and 503.7 ng/g, respectively. The results show that the mercury content in the fly ash from CFB boiler increases with decreasing particle size and reactivity temperature,but increasing surface area and unburned carbon content. For the fly ash from PC boiler, the portion with the diameter of 75-53 μm displays better mercury adsorption capability, the unburned carbon content is much lower than that from CFB boiler, and the surface area is almost independent to particle size. As a result, the adsorption capacity of the sample taken from the ash discharge port of the pulverized coal boiler dust removal equipment is much lower than that of the corresponding position of the circulating fluidized bed boiler.
引文
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[20]黄勋,程乐鸣,蔡毅,等.循环流化床中烟气飞灰汞迁移试验研究[J].化工学报,2014,65(4):1387-1395.Huang X,Cheng L M,Cai Y,et al.Mercury migration between flue gas and fly ash in circulating fluidized bed[J].CIESCJournal,2014,65(4):1387-1395.
[21]Best P E,Solomon P R,Serio M A,et al.Relationship between char reactivity and physical and chemical structural features[J].Prepr.Pap.Am.Chem.Soc.Div.Fuel Chem.(United States),1987,32:4.
[22]何宏舟.飞灰回燃对燃烧福建无烟煤CFB锅炉运行影响的研究[J].热能动力工程,2006,21(1):57-61+111.He H Z.An investigation of the impact of fly-ash re-burning on the operation of an anthracite-firing circulating fluidized bed boiler[J].Journal of Engineering for Thermal Energy and Power,2006,21(1):57-61+111.
[23]Shen C,Lin W,Wu S,et al.Experimental study of combustion characteristics of bituminous char derived under mild pyrolysis conditions[J].Energy&Fuels,2009,23(11):3084-3091.
[24]Chen C,Li Q,Tao D J,et al.Physical and chemical prosperities difference between pulverized coal boiler fly ash and circulating fluidized bed combustion ash[J].Asian Journal of Chemistry,2012,24(10):4538-4540.
[25]Sarkar D K.Fluidized-bed combustion boilers[M]//Thermal Power Plant.Elsevier,2015:159-187.
[26]Utt J,Giglio R.Technology comparison of CFB versus pulverized fuel firing for utility power generation[J].Journal of the Southern African Institute of Mining&Metallurgy,2012,112(6):449-454.
[27]Gao M Y,Kulatos I,Chen X,et al.The effect of solid fuel type and combustion conditions on residual carbon properties and fly ash quality[J].Proceedings of the Combustion Institute,2002,29(1):475-483.
[28]Wang Y,Duan Y,Yang L,et al.Experimental study on mercury transformation and removal in coal-fired boiler flue gases[J].Fuel Processing Technology,2009,90(5):643-651.
[29]Hower J C,Senior C L,Suuberg E M,et al.Mercury capture by native fly ash carbons in coal-fired power plants[J].Progress in Energy&Combustion Science,2010,36(4):510-529.
[30]Dunham G E,Dewall R A,Senior C L.Fixed-bed studies of the interactions between mercury and coal combustion fly ash[J].Fuel Processing Technology,2003,82(2):197-213.
[31]Suuberg E M.Thermally induced changes in reactivity of carbons[M]//Fundamental Issues in Control of Carbon Gasification Reactivity.Netherlands:Springer,1991:269-305.
[2]UNEP.Global mercury assessment 2013:sources,emissions,releases and environmental transport[R].Geneva,Switzerland:UNEP Chemicals Branch,2013.
[3]杜雯,殷立宝,禚玉群,等.100 MW燃煤电厂非碳基吸附剂喷射脱汞实验研究[J].化工学报,2014,65(11):4413-4419.Du W,Yin L B,Zhuo Y Q,et al Experimental study on mercury capture using non-carbon sorbents in 100 MW coal-fired power plant[J].CIESC Journal,2014,65(11):4413-4419.
[4]Pavlish J H,Sondreal E A,Mann M D,et al.Status review of mercury control options for coal-fired power plants[J].Fuel Process.Technol.,2003,82(2/3):89-165
[5]Galbreath K C,Zygarlicke C J.Mercury transformations in coal combustion flue gas[J].Fuel Processing Technology,2006,65(99):289-310.
[6]王铮,薛建明,许月阳,等.选择性催化还原协同控制燃煤烟气中汞排放效果影响因素研究[J].中国电机工程学报,2013,33(14):32-37.Wang Z,Xue J M,Xu Y Y,et al.Research on influencing factors of SCR's cooperative control in mercury emissions from coal-fired flue[J].Proceedings of the CSEE,2013,33(14):32-37.
[7]李建荣,何炽,商雪松,等.SCR脱硝催化剂对烟气中零价汞的氧化效率研究[J].燃料化学学报,2012,40(2):241-246.Li J R,He C,Shang X S,et al.Oxidation efficiency of elemental mercury in flue gas by SCR De-NOx catalysts[J].Journal of Fuel Chemistry and Technology,2012,40(2):241-246.
[8]Hower J C,Senior C L,Suuberg E M,et al.Mercury capture by native fly ash carbons in coal-fired power plants[J].Progress in Energy&Combustion Science,2010,36(4):510-529.
[9]Sakulpitakphon T,Hower J C,Trimble A S,et al.Mercury capture by fly ash:study of the combustion of a high-mercury coal at a utility boiler[J].Energy Fuels,2000,14(3):727-733.
[10]王鹏,吴江,任建兴,等.飞灰未燃尽碳对吸附烟气汞影响的试验研究[J].动力工程学报,2012,32(4):332-337.Wang P,Wu J,Ren J X,et al.Experimental study on influence of unburned carbon in fly ash on mercury adsorption in flue gas[J].Journal of Chinese Society of Power Engineering,2012,32(4):332-337.
[11]江贻满,段钰锋,杨祥花,等.ESP飞灰对燃煤锅炉烟气汞的吸附特性[J].东南大学学报(自然科学版),2007,37(3):436-440.Jiang Y M,Duan Y F,Yang X H,et.al.Adsorption characterization of coal fired flue gas mercury by ESP fly ashes[J].Journal of Southeast University(Natural Science Edition),2007,37(3):436-440.
[12]Kostova I,Vassileva C,Dai S,et al.Influence of surface area properties on mercury capture behavior of coal fly ashes from some Bulgarian power plants[J].International Journal of Coal Geology,2013,116/117(5):227-235.
[13]Maroto-Valer M M,Zhang Y,Granite E J,et al.Effect of porous structure and surface functionality on the mercury capacity of a fly ash carbon and its activated sample[J].Fuel,2005,84(1):105-108.
[14]程乐鸣,岑可法,倪明江,等.循环流化床锅炉炉膛热力计算[J].中国电机工程学报,2002,22(12):146-151.Cheng L M,Cen K F,Ni M J,et al.Thermal calculation of a circulating fluidized bed boiler furnace[J].Proceedings of the CSEE,2002,22(12):146-151.
[15]姜秀民,孙东红,闫澈,等.65t/h示范性油页岩循环流化床电厂锅炉运行实践[J].中国电机工程学报,2001,21(2):69-73.Jiang X M,Sun D H,Yan C,et al.Performance characteristics of65t/h oil shale-fired circulating fluidized bed demonstration utility boiler[J].Proceedings of the CSEE,2001,21(2):69-73.
[16]谢磊,毛国明,金晓明,等.循环流化床锅炉燃烧过程预测控制与经济性能优化[J].化工学报,2016,67(3):695-700.Xie L,Mao G M,Jin X M,et.al.Predictive control and economic performance optimization of CFBB combustion process[J].CIESCJournal,2016,67(3):695-700.
[17]Yue G,Cai R,Lu J,et al.From a CFB reactor to a CFB boilerthe review of R&D progress of CFB coal combustion technology in China[J].Powder Technology,2017,316:18-28.
[18]樊保国,贾里,李晓栋,等.电站燃煤锅炉飞灰特性对其吸附汞能力的影响[J].动力工程学报,2016,36(8):621-628.Fan B G,Jia L,Li X D.et al.Study on mercury adsorption by fly ash form coal-fired coilers of power plants[J].Journal of Chinese Society of Power Engineering,2016,36(8):621-628.
[19]段钰锋,江贻满,杨立国,等.循环流化床锅炉汞排放和吸附实验研究[J].中国电机工程学报,2008,28(32):1-5.Duan Y F,Jiang Y M,Yang L G,et al.Experimental study on mercury emission and adsorption in circulating fluidized bed boiler[J].Proceedings of the CSEE,2008,28(32):1-5.
[20]黄勋,程乐鸣,蔡毅,等.循环流化床中烟气飞灰汞迁移试验研究[J].化工学报,2014,65(4):1387-1395.Huang X,Cheng L M,Cai Y,et al.Mercury migration between flue gas and fly ash in circulating fluidized bed[J].CIESCJournal,2014,65(4):1387-1395.
[21]Best P E,Solomon P R,Serio M A,et al.Relationship between char reactivity and physical and chemical structural features[J].Prepr.Pap.Am.Chem.Soc.Div.Fuel Chem.(United States),1987,32:4.
[22]何宏舟.飞灰回燃对燃烧福建无烟煤CFB锅炉运行影响的研究[J].热能动力工程,2006,21(1):57-61+111.He H Z.An investigation of the impact of fly-ash re-burning on the operation of an anthracite-firing circulating fluidized bed boiler[J].Journal of Engineering for Thermal Energy and Power,2006,21(1):57-61+111.
[23]Shen C,Lin W,Wu S,et al.Experimental study of combustion characteristics of bituminous char derived under mild pyrolysis conditions[J].Energy&Fuels,2009,23(11):3084-3091.
[24]Chen C,Li Q,Tao D J,et al.Physical and chemical prosperities difference between pulverized coal boiler fly ash and circulating fluidized bed combustion ash[J].Asian Journal of Chemistry,2012,24(10):4538-4540.
[25]Sarkar D K.Fluidized-bed combustion boilers[M]//Thermal Power Plant.Elsevier,2015:159-187.
[26]Utt J,Giglio R.Technology comparison of CFB versus pulverized fuel firing for utility power generation[J].Journal of the Southern African Institute of Mining&Metallurgy,2012,112(6):449-454.
[27]Gao M Y,Kulatos I,Chen X,et al.The effect of solid fuel type and combustion conditions on residual carbon properties and fly ash quality[J].Proceedings of the Combustion Institute,2002,29(1):475-483.
[28]Wang Y,Duan Y,Yang L,et al.Experimental study on mercury transformation and removal in coal-fired boiler flue gases[J].Fuel Processing Technology,2009,90(5):643-651.
[29]Hower J C,Senior C L,Suuberg E M,et al.Mercury capture by native fly ash carbons in coal-fired power plants[J].Progress in Energy&Combustion Science,2010,36(4):510-529.
[30]Dunham G E,Dewall R A,Senior C L.Fixed-bed studies of the interactions between mercury and coal combustion fly ash[J].Fuel Processing Technology,2003,82(2):197-213.
[31]Suuberg E M.Thermally induced changes in reactivity of carbons[M]//Fundamental Issues in Control of Carbon Gasification Reactivity.Netherlands:Springer,1991:269-305.