钙基脱硫剂固硫特性的试验研究
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摘要
利用热重分析法、微观结构表征法研究了2种钙基脱硫剂(石灰石Ⅰ,Ⅱ)固硫反应特性,揭示了钙基脱硫剂固硫反应机理,并通过等效粒子法模型分析了石灰石固硫反应动力学特性。研究结果表明:在800~900℃温度范围内,石灰石钙转化率随温度提高而增强;石灰石粒径越小,钙转化率越高。石灰石Ⅰ钙利用率对温度敏感,而石灰石Ⅱ对粒径敏感。石灰石煅烧后在晶粒表面形成的裂纹促进SO2的扩散,有利于固硫反应的进行。动力学计算结果表明,石灰石Ⅱ在扩散控制阶段有较高的有效扩散系数,最终钙利用率高于石灰石Ⅰ。
The desulfurization characteristics of two calcium-based sorbents(limestoneⅠand Ⅱ) were investigated by thermogravimetry and microstructure characterization technique to reveal the reaction mechanism of desulfurization. The equivalent particle approach model was used to analyze the reaction kinetics. The results show that the calcium utilization increases with the temperature increase in a temperature range of 800 ~900℃, and increases with the particle diameter decreases. The limestone Ⅰ is sensitive to the temperature while limestone Ⅱ is sensitive to particle diameter. After calcinations of limestone, the cracks on the grains increase the SO_2 diffusion, which is conducive to the desulfurization process. The kinetic analysis shows that the large effective diffusivity in the diffusion controlled stage contributes to the higher calcium utilization for limestone Ⅱ, which is superior to limestone I in calcium utilization.
The desulfurization characteristics of two calcium-based sorbents(limestoneⅠand Ⅱ) were investigated by thermogravimetry and microstructure characterization technique to reveal the reaction mechanism of desulfurization. The equivalent particle approach model was used to analyze the reaction kinetics. The results show that the calcium utilization increases with the temperature increase in a temperature range of 800 ~900℃, and increases with the particle diameter decreases. The limestone Ⅰ is sensitive to the temperature while limestone Ⅱ is sensitive to particle diameter. After calcinations of limestone, the cracks on the grains increase the SO_2 diffusion, which is conducive to the desulfurization process. The kinetic analysis shows that the large effective diffusivity in the diffusion controlled stage contributes to the higher calcium utilization for limestone Ⅱ, which is superior to limestone I in calcium utilization.
引文
[1]张军,郑成航,张涌新,等.某1 000 MW燃煤机组超低排放电厂烟气污染物排放测试及其特性分析[J].中国电机工程学报,2016(5):1310-1314.
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[12]魻ZER A K,G譈LABO譏IU M S,BAYRAKCEKEN S,et al.Changes in physical structure and chemical composition of phosphate rock during calcination in fluidized and fixed beds[J].Advanced Powder Technology,2006,17(5):481-494.
[13]HAN K,LU C,CHENG S,et al.Effect of characteristics of calcium-based sorbents on the sulfation kinetics[J].Fuel,2005,84(14-15):1933-1939.
[14]LI Y,QI H,YOU C,et al.Kinetic model of Ca O/fly ash sorbent for flue gas desulphurization at moderate temperatures[J].Fuel,2007,86(5-6):785-792.
[15]KARATEPE N,ERDOGAN N,ERSOY-MERICBOYU A,et al.Preparation of diatomite/Ca(OH)2sorbents and modelling their sulphation reaction[J].Chemical Engineering Science,2004,59(18):3883-3889.
[2]MURA G,LALLAI A,OLLA P.On the kinetics of dry desulfurization with calcium oxide[J].The Chemical Engineering Journal,1991,46(3):119-128.
[3]AD魣NEZ J,LABIANO F G,AB魣NADES J C,et al.Methods for characterization of sorbents used in fluidized bed boilers[J].Fuel,1994,73(3):355-362.
[4]ERSOY MERI覶BOYU A,K譈覶譈KBAYRAK S,YAMANS.Sulphation capacities of natural Turkish limestones and dolomites[J].Environmental Technology,1993,14(8):787-794.
[5]FAN L,SATIJA S,WILSON W I,et al.Thermogravimetric analysis of sulfation kinetics of calcined limestones or dolomites[J].The Chemical Engineering Journal,1984,28(3):151-162.
[6]DE DIEGO L F,DE LAS OBRAS-LOSCERTALES M,GARCIA-LABIANO F,et al.Characterization of a limestone in a batch fluidized bed reactor for sulfur retention under oxy-fuel operating conditions[J].International Journal of Greenhouse Gas Control,2011,5(5):1190-1198.
[7]CHAN R K,MURTHI K S,HARRISON D.Reaction of sulfur dioxide with calcined limestones and dolomites[J].Environmental Science&Technology,1971,5(9):776-781.
[8]REID W T.BASIC FACTORS in the Capture of Sulfur Dioxide by Limestone and Dolomite[J].Journal of Engineering for Gas Turbines and Power,1970,92(1):11-15.
[9]SCALA F,SALATINO P.Dolomite attrition during fluidized-bed calcination and sulfation[J].Combustion Science and Technology,2003,175(12):2201-2216.
[10]魻ZER A K,G譈LABO譏IU M S,BAYRAK覶EKEN S,et al.Flue gas desulfurization with phosphate rock in a fluidized bed[J].Fuel,2002,81(1):41-49.
[11]魻ZER A K,G譈LABO譏IU M S,BAYRAKCEKEN S.Physical Structure and Chemical and Mineralogical Composition of the Mazidag1(Turkey)Phosphate Rock[J].Industrial&Engineering Chemistry Research,2000,39(3):679-683.
[12]魻ZER A K,G譈LABO譏IU M S,BAYRAKCEKEN S,et al.Changes in physical structure and chemical composition of phosphate rock during calcination in fluidized and fixed beds[J].Advanced Powder Technology,2006,17(5):481-494.
[13]HAN K,LU C,CHENG S,et al.Effect of characteristics of calcium-based sorbents on the sulfation kinetics[J].Fuel,2005,84(14-15):1933-1939.
[14]LI Y,QI H,YOU C,et al.Kinetic model of Ca O/fly ash sorbent for flue gas desulphurization at moderate temperatures[J].Fuel,2007,86(5-6):785-792.
[15]KARATEPE N,ERDOGAN N,ERSOY-MERICBOYU A,et al.Preparation of diatomite/Ca(OH)2sorbents and modelling their sulphation reaction[J].Chemical Engineering Science,2004,59(18):3883-3889.