半干法脱硫剂的性能及脱硫机理
|
摘要
在固定床脱硫实验平台上探究低温低含水率条件下,制备钙基脱硫剂的脱硫过程及脱硫机理。采用BET表征手段对脱硫剂的孔隙结构进行表征,X射线能谱分析脱硫剂中活性氧化钙的含量。结果表明:根据脱硫反应速率与扩散速率的差值,将钙基脱硫剂的脱硫过程分为动力段、平衡段和过渡段三个阶段,脱硫效率在动力段由脱硫反应速率控制,在过渡段由气体扩散速率控制,提高脱硫效率即减小脱硫反应速率与气体扩散速率的差值;随着含水率的增加,有效脱硫时间和最大脱硫效率分别呈现递增和递减的趋势,本实验中脱硫效率最大为100%,有效脱硫时间最长为55.47min,粉煤灰和熟石灰掺混比(质量比)不同的脱硫剂有效物质含量以及脱硫剂孔隙结构均发生变化,最佳掺混比为3∶1;在过渡段中存在脱硫效率的小幅度上升,当含水率越小,粉煤灰占比越大过渡段脱硫效率的上升趋势越明显,上升段主要发生在中小孔径区域。
The desulfurization process and mechanism of calcium-based adsorbent prepared at low temperature and low moisture content were studied on a fixed bed desulfurization test platform,the pore structure of desulfurizer was characterized by BET and the content of active calcium oxide in desulfurizer was analyzed by X-ray energy spectrum.The experimental results show that according to the difference between desulfurization reaction rate and diffusion rate,the desulfurization process of calcium-based adsorbent can be divided into three stages:power stage,equilibrium stage and transition stage.The desulfurization efficiency is controlled by desulfurization reaction rate and gas diffusion rate in the power stage and transition stage,respectively.To improve desulfurization efficiency is to reduce the difference between desulfurization reaction rate and gas diffusion rate.With the increase of moisture content,the effective desulfurization time and maximum desulfurization efficiency show an increasing and decreasing trend,respectively.The maximum desulfurization efficiency is 100% and the maximum desulfurization time is 55.47 min.The content of effective substances and pore structure of adsorbent vary with the mixing ratio.The optimum mixing ratio of fly ash and slaked lime in this paper is3∶1.And there is a small increasing of desulfurization efficiency in the transition stage.When the moisture content of adsorbent is smaller,the more proportion of fly ash.And at the same time,the increasing trend of desulfurization efficiency in the transition stage is more obvious.Furthermore,the rising stage mainly occurred in the small poles and mesopores.
The desulfurization process and mechanism of calcium-based adsorbent prepared at low temperature and low moisture content were studied on a fixed bed desulfurization test platform,the pore structure of desulfurizer was characterized by BET and the content of active calcium oxide in desulfurizer was analyzed by X-ray energy spectrum.The experimental results show that according to the difference between desulfurization reaction rate and diffusion rate,the desulfurization process of calcium-based adsorbent can be divided into three stages:power stage,equilibrium stage and transition stage.The desulfurization efficiency is controlled by desulfurization reaction rate and gas diffusion rate in the power stage and transition stage,respectively.To improve desulfurization efficiency is to reduce the difference between desulfurization reaction rate and gas diffusion rate.With the increase of moisture content,the effective desulfurization time and maximum desulfurization efficiency show an increasing and decreasing trend,respectively.The maximum desulfurization efficiency is 100% and the maximum desulfurization time is 55.47 min.The content of effective substances and pore structure of adsorbent vary with the mixing ratio.The optimum mixing ratio of fly ash and slaked lime in this paper is3∶1.And there is a small increasing of desulfurization efficiency in the transition stage.When the moisture content of adsorbent is smaller,the more proportion of fly ash.And at the same time,the increasing trend of desulfurization efficiency in the transition stage is more obvious.Furthermore,the rising stage mainly occurred in the small poles and mesopores.
引文
[1]DE GISI S,MOLINO A,NOTARNICOLA M.Enhancing the Recovery of Gypsum in Limestone-based Wet Flue Gas Desulfurization with High Energy Ball Milling Process:A Feasibility Study[J].Process Safety and Environmental Protection,2017(109):117-129.
[2]SHENG Guanghong,LI Qin,ZHAI Jianping.Investigation on the Hydration of CFBC Fly Ash[J].Fuel,2012,98:61-66.
[3]宗润宽,苏艳霞,胡金榜,等.钙基烟气脱硫剂的生产研究进展[J].化工进展,2001,20(12):12-15.ZONG Runkuan,SU Yanxia,HU Jinbang,et al.Progress of the Study on Production of Calcium Based on Absorbent for Flue Gas Desulfurization[J].Chemical Industry and Engineering Progress,2001,20(12):12-15.
[4]GRKEM B,OGˇUZ H.Development of an Active Sorbent from Fly Ash for Dry Desulphurization of Simulated Flue Gas in a Fluidized-bed Reactor[J].Chemical Engineering Journal,2006,119(1/2):147-152.
[5]MONTAGNARO F,NOBILI M,TELESCA A,et al.Steam Hydration-reactivation of FBC Ashes for Enhanced in Situ Desulphurization[J].Fuel,2009,88(6):1092-1098.
[6]李婷,肖翠微,张鑫,等.粉煤灰在燃煤锅炉烟气脱硫中的应用[J].洁净煤技术,2013,19(5):82-84.LI Ting,XIAO Cuiwei,ZHANG Xin,et al.Application of Fly Ash in Coal-fired Boiler Flue Gas Desulfurization[J].Clean Coal Technology,2013,19(5):82-84.
[7]LI Yuran,QI Haiying,YOU C F,et al.Kinetic Model of CaO/fly Ash Sorbent for Flue Gas Desulphurization at Moderate Temperatures[J].Fuel,2007,86(5/6):785-792.
[8]CHEN Guoqiang,GAO Jihui,WANG Shuang,et al.Enhancement Effects of Gas Components on NO Removal by Calcium Hydroxide[J].Industrial and Engineering Chemistry Research,2010,49(3):1450-1456.
[9]LIU Chiungfang,SHIH Shinmin,LIN Renbin.Kinetics of the Reaction of Ca(OH)2/fly Ash Sorbent with SO2at Low Temperatures[J].Chemical Engineering Science,2002,57(1):93-104.
[10]陈国庆,高继慧,尹伊郡,等.同时脱硫脱硝过程中钙基吸收剂表面孔隙结构变化规律[J].中国电机工程学报,2011,31(20):60-66.CHEN Guoqing,GAO Jihui,YIN Yijun,et al.Evolution of Pore Structure of Ca-based Sorbent in Simultaneous Removal of SO2and NOx[J].Proceedings of the Chinese Society of Electrical Engineering,2011,31(20):60-66.
[11]王世昌,姚强,徐旭常.CaO脱硫化学反应速率与气体扩散速率对比[J].工程热物理学报,2006,27(增刊2):219-222.WANG Shichang,YAO Qiang,XU Xuchang.Comparison of Kinetic Reaction Rate and Diffusion Rate During Dry FGD Reaction with CaO Particles[J].Journal of Engineering Thermophysics,2006,27(Supplement 2):219-222.
[12]MASAYOSHI Sadakata,TAKASHI Shinob,AZUCHI Harand,et al.Removal of SO2from Flue Gas Using Ultrafine CaOParticles[J].Journal of Chemical Engineering of Japan,1994,27(4):550-552.
[13]WANG Tao,XIAO Gao,ZHAO Ling,et al.The Catalysts Performance of[Bmim]6PMO9V3O40/ACF on Flue Gas Desulfurization[J].Materials Science Forum,2013,743/744:751-758.
[14]赵长遂,吴树志,刘现卓,等.增湿活化反应器内喷水脱硫试验研究[J].工程热物理学报,2002,23(4):505-508.ZHAO Changsui,WU Shuzhi,LIU Xianzhuo,et al.Investigation on Flue Gas Desulfurization Activated by Humidification in Reactor[J].Journal of Engineering Thermophysics,2002,23(4):505-508.
[15]付颖,钱枫,周芸芸.燃煤飞灰制备脱硫剂的试验研究[J].环境科学与技术,2006,29(8):91-92.FU Ying,QIAN Feng,ZHOU Yunyun.Desulfurization Absorbent Prepared with Fly Ash and Lime[J].Environmental Science and Technology,2006,29(8):91-92.
[16]王河山,尚建宇,王松岭,等.钙基脱硫剂硫化反应产物层扩散机理研究进展[J].电力科学与工程,2009,25(1):62-65.WANG Heshan,SHANG Jianyu,WANG Songling,et al.Research Development on the Diffusion in Sulfidation Reaction Product Layer of Cabased Sorbents[J].Electric Power Science and Engineering,2009,25(1):62-65.
[17]缪明烽,沈湘林.钙基脱硫剂孔隙分布特性的模拟研究[J].东南大学学报(自然科学版),2001,31(2):68-71.MIAO Mingfeng,SHEN Xianglin.Modeling Investigation on the Characteristics of Pore Distributions of Calcium Based Sorbents[J].Journal of Southeast University(Natural Science Edition),2001,31(2):68-71.
[18]ORTIZ M I,GAREA A,IRABIEN A,et al.Flue Gas Desulfurization at Low Temperatures.Characterization of the Structural Changes in the Solid Sorbent[J].Powder Technology,1993,75(2):167-172.
[2]SHENG Guanghong,LI Qin,ZHAI Jianping.Investigation on the Hydration of CFBC Fly Ash[J].Fuel,2012,98:61-66.
[3]宗润宽,苏艳霞,胡金榜,等.钙基烟气脱硫剂的生产研究进展[J].化工进展,2001,20(12):12-15.ZONG Runkuan,SU Yanxia,HU Jinbang,et al.Progress of the Study on Production of Calcium Based on Absorbent for Flue Gas Desulfurization[J].Chemical Industry and Engineering Progress,2001,20(12):12-15.
[4]GRKEM B,OGˇUZ H.Development of an Active Sorbent from Fly Ash for Dry Desulphurization of Simulated Flue Gas in a Fluidized-bed Reactor[J].Chemical Engineering Journal,2006,119(1/2):147-152.
[5]MONTAGNARO F,NOBILI M,TELESCA A,et al.Steam Hydration-reactivation of FBC Ashes for Enhanced in Situ Desulphurization[J].Fuel,2009,88(6):1092-1098.
[6]李婷,肖翠微,张鑫,等.粉煤灰在燃煤锅炉烟气脱硫中的应用[J].洁净煤技术,2013,19(5):82-84.LI Ting,XIAO Cuiwei,ZHANG Xin,et al.Application of Fly Ash in Coal-fired Boiler Flue Gas Desulfurization[J].Clean Coal Technology,2013,19(5):82-84.
[7]LI Yuran,QI Haiying,YOU C F,et al.Kinetic Model of CaO/fly Ash Sorbent for Flue Gas Desulphurization at Moderate Temperatures[J].Fuel,2007,86(5/6):785-792.
[8]CHEN Guoqiang,GAO Jihui,WANG Shuang,et al.Enhancement Effects of Gas Components on NO Removal by Calcium Hydroxide[J].Industrial and Engineering Chemistry Research,2010,49(3):1450-1456.
[9]LIU Chiungfang,SHIH Shinmin,LIN Renbin.Kinetics of the Reaction of Ca(OH)2/fly Ash Sorbent with SO2at Low Temperatures[J].Chemical Engineering Science,2002,57(1):93-104.
[10]陈国庆,高继慧,尹伊郡,等.同时脱硫脱硝过程中钙基吸收剂表面孔隙结构变化规律[J].中国电机工程学报,2011,31(20):60-66.CHEN Guoqing,GAO Jihui,YIN Yijun,et al.Evolution of Pore Structure of Ca-based Sorbent in Simultaneous Removal of SO2and NOx[J].Proceedings of the Chinese Society of Electrical Engineering,2011,31(20):60-66.
[11]王世昌,姚强,徐旭常.CaO脱硫化学反应速率与气体扩散速率对比[J].工程热物理学报,2006,27(增刊2):219-222.WANG Shichang,YAO Qiang,XU Xuchang.Comparison of Kinetic Reaction Rate and Diffusion Rate During Dry FGD Reaction with CaO Particles[J].Journal of Engineering Thermophysics,2006,27(Supplement 2):219-222.
[12]MASAYOSHI Sadakata,TAKASHI Shinob,AZUCHI Harand,et al.Removal of SO2from Flue Gas Using Ultrafine CaOParticles[J].Journal of Chemical Engineering of Japan,1994,27(4):550-552.
[13]WANG Tao,XIAO Gao,ZHAO Ling,et al.The Catalysts Performance of[Bmim]6PMO9V3O40/ACF on Flue Gas Desulfurization[J].Materials Science Forum,2013,743/744:751-758.
[14]赵长遂,吴树志,刘现卓,等.增湿活化反应器内喷水脱硫试验研究[J].工程热物理学报,2002,23(4):505-508.ZHAO Changsui,WU Shuzhi,LIU Xianzhuo,et al.Investigation on Flue Gas Desulfurization Activated by Humidification in Reactor[J].Journal of Engineering Thermophysics,2002,23(4):505-508.
[15]付颖,钱枫,周芸芸.燃煤飞灰制备脱硫剂的试验研究[J].环境科学与技术,2006,29(8):91-92.FU Ying,QIAN Feng,ZHOU Yunyun.Desulfurization Absorbent Prepared with Fly Ash and Lime[J].Environmental Science and Technology,2006,29(8):91-92.
[16]王河山,尚建宇,王松岭,等.钙基脱硫剂硫化反应产物层扩散机理研究进展[J].电力科学与工程,2009,25(1):62-65.WANG Heshan,SHANG Jianyu,WANG Songling,et al.Research Development on the Diffusion in Sulfidation Reaction Product Layer of Cabased Sorbents[J].Electric Power Science and Engineering,2009,25(1):62-65.
[17]缪明烽,沈湘林.钙基脱硫剂孔隙分布特性的模拟研究[J].东南大学学报(自然科学版),2001,31(2):68-71.MIAO Mingfeng,SHEN Xianglin.Modeling Investigation on the Characteristics of Pore Distributions of Calcium Based Sorbents[J].Journal of Southeast University(Natural Science Edition),2001,31(2):68-71.
[18]ORTIZ M I,GAREA A,IRABIEN A,et al.Flue Gas Desulfurization at Low Temperatures.Characterization of the Structural Changes in the Solid Sorbent[J].Powder Technology,1993,75(2):167-172.