异极性荷电粉尘在电场中的凝并与收集
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摘要
与传统的静电除尘器相比,电凝并除尘装置由于能够有效的收集亚微米级粉尘而备受人们的青睐。本文对异极性荷电粉尘在交变电场及脉冲电场中的凝并行为进行了较为深入的研究。取得了以下主要研究成果:
1)将三区式异极性荷电粉尘交变凝并除尘装置改进为双区式。其创新之处为在凝并区内同时实现粉尘的荷电与凝并。其优越性在于可使粉尘反复荷电与凝并,荷电粉尘凝并后,其表面积增大,再次荷电后,电量增加,因此凝并效果好;将预荷电区与凝并区合二为一,缩短了电极总长度,降低了除尘器成本。
2)通过改变凝并区介质阻挡(Dielectric Barrier Discharge, DBD)反应器放电类型,提出了粉尘在脉冲电场中的异极性荷电新方法。并对两种放电条件下粉尘的除尘效率进行了对比研究,结果表明,异极性荷电粉尘在脉冲电场中的凝并效果略优于交变电场。另外,本研究考察了凝并区反应器结构对电凝并除尘装置的影响,开发了一种新型的点对点(Point to Point, PTP)放电反应器,扩展了凝并装置结构类型的研究。
3)通过对粉尘在脉冲电场中荷电机理的分析,提出其荷电过程分为两个阶段,在脉冲放电周期的电子荷电及脉冲放电过后的离子荷电。
4)应用类似于Williams求声凝并系数的方法导出了异极性荷电粉尘在交变电场中的凝并系数,并根据关于粉尘凝并过程趋于“自保分布”的概念,建立了异极性荷电粉尘在交变电场中的凝并除尘效率的数学表达式。
Electrical agglomeration is supposed to be an efficient method to improve the collection efficiency of the electrostatic precipitator (ESP) for collecting the submicron particles. Experiments were carried out to investigate agglomeration charactertistics of bipolar charged particles in alternative current (AC) and pulsed electric field. The results are summarized as follows:
1) A new-type electrostatic agglomerator with two zones was developed. The distinguishing feature of this elcectrostatic agglomerator is that the parcicles are bipolarly charged and coagulated in the same AC electric field simultaneously. And there are two advantages: the particles can be charged and agglomerated repeatedly. When the particles are agglomerated into a larger particle, the surface area becomes greater. The charge on the agglomerated particles is increased when this particle is charged again. Thus, the agglomeration rate gose up; because the particles can be bipolarly charged in the AC electric field, it is not necessary to have a precharging zone. Therefore, the total length of the electric field becomes shorter in the application.
2) According to changing discharge type of DBD reactor, a new bipolarly charged method of particles in pulsed electric field was proposed. The comparison experimental results have shown that the collection efficiency of bipolar charged particles in pulsed electric field is higher than that in AC electric field. Furthermore, a PTP reactor was designed to investigate the influence of reactor structure on collection efficiency of electrostatic agglomerator.
3) The theory of particle charging in pulsed electric field was established. The particle charging process is divided into two periods, the electron charging in pulse discharge duration and the ion charging after the pulse discharge duration.
4) Formula to calculate the coagulation coefficient of bipolar particles in AC electiec field was proposed by adapting the method that was developed by Williams to evaluate the acoustic coagulation coefficient. According to the concept of the self-preserving in particle size distribution, the collection efficiency of electrostatic agglomerator was determined theoretically.
1)将三区式异极性荷电粉尘交变凝并除尘装置改进为双区式。其创新之处为在凝并区内同时实现粉尘的荷电与凝并。其优越性在于可使粉尘反复荷电与凝并,荷电粉尘凝并后,其表面积增大,再次荷电后,电量增加,因此凝并效果好;将预荷电区与凝并区合二为一,缩短了电极总长度,降低了除尘器成本。
2)通过改变凝并区介质阻挡(Dielectric Barrier Discharge, DBD)反应器放电类型,提出了粉尘在脉冲电场中的异极性荷电新方法。并对两种放电条件下粉尘的除尘效率进行了对比研究,结果表明,异极性荷电粉尘在脉冲电场中的凝并效果略优于交变电场。另外,本研究考察了凝并区反应器结构对电凝并除尘装置的影响,开发了一种新型的点对点(Point to Point, PTP)放电反应器,扩展了凝并装置结构类型的研究。
3)通过对粉尘在脉冲电场中荷电机理的分析,提出其荷电过程分为两个阶段,在脉冲放电周期的电子荷电及脉冲放电过后的离子荷电。
4)应用类似于Williams求声凝并系数的方法导出了异极性荷电粉尘在交变电场中的凝并系数,并根据关于粉尘凝并过程趋于“自保分布”的概念,建立了异极性荷电粉尘在交变电场中的凝并除尘效率的数学表达式。
Electrical agglomeration is supposed to be an efficient method to improve the collection efficiency of the electrostatic precipitator (ESP) for collecting the submicron particles. Experiments were carried out to investigate agglomeration charactertistics of bipolar charged particles in alternative current (AC) and pulsed electric field. The results are summarized as follows:
1) A new-type electrostatic agglomerator with two zones was developed. The distinguishing feature of this elcectrostatic agglomerator is that the parcicles are bipolarly charged and coagulated in the same AC electric field simultaneously. And there are two advantages: the particles can be charged and agglomerated repeatedly. When the particles are agglomerated into a larger particle, the surface area becomes greater. The charge on the agglomerated particles is increased when this particle is charged again. Thus, the agglomeration rate gose up; because the particles can be bipolarly charged in the AC electric field, it is not necessary to have a precharging zone. Therefore, the total length of the electric field becomes shorter in the application.
2) According to changing discharge type of DBD reactor, a new bipolarly charged method of particles in pulsed electric field was proposed. The comparison experimental results have shown that the collection efficiency of bipolar charged particles in pulsed electric field is higher than that in AC electric field. Furthermore, a PTP reactor was designed to investigate the influence of reactor structure on collection efficiency of electrostatic agglomerator.
3) The theory of particle charging in pulsed electric field was established. The particle charging process is divided into two periods, the electron charging in pulse discharge duration and the ion charging after the pulse discharge duration.
4) Formula to calculate the coagulation coefficient of bipolar particles in AC electiec field was proposed by adapting the method that was developed by Williams to evaluate the acoustic coagulation coefficient. According to the concept of the self-preserving in particle size distribution, the collection efficiency of electrostatic agglomerator was determined theoretically.
引文
[1] 吴超,化学抑尘,长沙:中南大学出版社,2003
[2] 赵振奇,梁学邈,工业企业粉尘控制工程综合评价,北京:冶金工业出版社,2002
[3] 崔九思,室内空气污染监测方法,北京:化学工业出版社,2002
[4] 闫艳,张士强,赵国华等,某煤矿 1964～1995 年间尘肺发病情况的分析,河南预防医学杂志,2005,13(3):158～159
[5] 周振起,张炳文,输煤系统粉尘污染治理技术,环境污染治理技术与设备,2005,6(6):64～66
[6] Biswas P,Wu C,Nanoparticles and the environment,Journal of the Air & Waste Management Association,2005,55(3):708～746
[7] 向晓东,现代除尘理论与技术,北京:冶金工业出版社,2002
[8] 吴忠标,李伟,王莉红,城市大气环境概论,北京:化学工业出版社,2003
[9] 熊振湖,费学宁,池勇志等,大气污染防治技术及工程应用,北京:机械工业出版社,2003
[10] 姜安玺,气体污染控制,北京:化学工业出版社,2003
[11] 童志权,工业废气净化与利用,北京:化学工业出版社,2001
[12] 王显龙,何立波,贾明生等,静电除尘器的新应用及其发展方向,工业安全与环保,2003,29(11):3～6
[13] Fuchs N A,Mechanics of Aerosol,New York:Pergamon Press,1964
[14] Eliasson B,Miller J,Coagulation of bipolarly charged aerosols in a stack coagulator,Journal of Aerosol Science,1987,18(3): 869～872
[15] Williams M M ,Loyalka S K, Aerosol Science Theory and Practice,New York:Pergamon Press,1991
[16] Watanabe T,Tochikubo F,Koizumi Y,et al.,Submicron particle agglomeration by an electrostatic agglomerator,Journal of Electrostatics,1995,34(4):367～383
[17] Kauppinen E I,Maenhaut W,Lind T,Electrical combustion aerosol agglomeration, Journal of Aerosol Science,1993,24(1):11～12
[18] Hautanen J,Kilpelainen M,Kauppinen E,et al.,Electrical agglomeration of aerosol particles in an alternating electric field,Aerosol Science and Technology,1993,22(2):181～189
[19] Xiang X D,Colbeck I,Coagulation and wall loss of charged particles,Journal of Aerosol Science,1993,24(3):135～136
[20] Kanazawa S,Ohkuho T,Nomoto Y,Submicron particle agglomeration and precipitation by using a bipolar charging method,Journal of Electrostatics,1993,23(5):193～209
[21] Gutsch A,Loffer F,Electrically enhanced agglomeration of nanosized aerosol,Journal of Aerosol Science,1994,25(3):307～308
[22] Koizumi Y,Tochikubo F,Watanabe T,et al.,Bipolar-charged submicron particle agglomeration,Journal of Electrostatics, 1995,35(1):55～60
[23] Vemury S,Jansen C,Pratsinis S E,Coagulation of symmetric and asymmetric bipolar aerosol,Journal of Aerosol Science,1997, 28(4):599～611
[24] 向晓东,电凝并理论及在除尘应用中的新进展,通风除尘,1994,13 (4):28～31
[25] Lehtinen K,Jokiniemi J,Kauppinen E,Kinematic coagulation of charged droplets in an alternating electric field,Aerosol Science and Technology,1995,23(4):422～430
[26] Kildes J,Bhatia V K,Lind J,et al.,An experimental investigation for agglomeration of aerosols in alternating electric field,Aerosol Science and Technology,1995,23(4):603～610
[27] Laiainen A,Hautanen J,Keskinen J,et al.,Bipolar charged aerosol agglomeration with alternating electric field in laminar gas flow,Jouranl of Electrostatics,1996,38(4):303～315
[28] 向晓东,陈宝智,张国权,荷电粉尘在交变电场中的凝并与收集,东北大学学报,1999,20(6):615～617
[29] 陈旺生,向晓东,幸福堂,交变电场频率对电凝并影响的理论及实验研究,武汉冶金科技大学学报,1999,22(4):342～344
[30] Ji J H,Hwang J,Bae G N,Particle charging and agglomeration in DC and AC electic fields, Jouranl of Electrostatics,2004,61 (1):57～68
[31] Xiang X D,Colbeck I,Charged water dorps and smoke dissipation, Fire Safety Jouranl,1997,28(2):227～232
[32] 向晓东,陈旺生,幸福堂等,烟尘在交变电场中的电凝并收集,武汉冶金科技大学学报,1999,22(3):252～255
[33] 向晓东,陈旺生,幸福堂等,交变电场中电凝并收尘理论与实验研究,环境科学学报,2000,20(2):187～191
[34] 白敏冬,张芝涛,储金宇等,电离放电特征参量时空演变规律及其除尘应用的基础研究,中国基础科学,2006,8(2):14～19
[35] 陈旺生,向晓东,幸福堂,交变电场中偶极荷电粒子电凝并的理论研究,工业安全与防尘,2001,27(2):3～5
[36] Koizumi Y,Kawamura M,Tochikubo F,et al.,Estimation of the agglomeration coefficient of bipolar charged aerosol particles,Journal of Electrostatics,2000,48(2):93～101
[37] Yamamoto T,Ramanathan K,Lawless P,et al.,Control of volatile organic compounds by an ac energized ferroelectric pellet reactor and a pulsed corona reactor,IEEE Transactions Industry Application,1992,28(3):528～534
[38] Nunez C M,Ramsey G H,Ponder W H,et al.,Corona destruction: an innovative control technology for VOCs and air toxics,Air Waste,1993,43(2):242～247
[39] Nozaki T,Unno Y,Miyazaki Y,et al.,A clear distinction of plasma structure between APG and DBD.15th International Symposium on Plasma Chemistry,Orleans-France,2001,1:77～83
[40] 许德玄,静电除尘预荷电的研究,环境工程,1997,15(6):25～28
[41] Yao S,Zhang X,Lu B,Influence of plasma reactor structure on methanol oxidation,AIChE Journal,2005,51(5):1558～1564
[42] Seok J P,Sang S K,Effects of particle space charge and turbulent diffusion on performance of plate-plate electrostatic precipitators,Jouranl of Electrostatics,1998,45(2):121～137
[43] Zhang X,Wang L,Zhu K,An analysis of a wire-plate electrostatic precipitator,Journal of Aerosol Science,2002,33(11):1595 ～1600
[44] Laskin A,Cowin J P,On deposition efficiency of point-to-plate electrostatic precipitator, Journal of Aerosol Science,2002,33(3):405～409
[45] Yao S,Okumoto M,Yashima T,et al.,Diesel Praticulate Matter and NOx Removals Using a Pulsed Corona Surface Discharge, AIChE Journal,2004,50(3):715～721
[46] Yao S,Okumoto M,Madokoro K,et al.,A pulsed dielectric barrierdischarge reactor for diesel particulate matter removal, AIChE Journal,2004,50(8):1901～1907
[47] 吴彦,王荣毅,王宁会,脉冲电压下粒子荷电的实验研究,大连理工大学学报,1995,35(3):309～311
[48] Martin C,Air Pollution control theory,New York:McGraw-Hill Book Company,1976
[49] Smith W B,McDonald R,Calulation of the charging Rate of fine particles by unipolar ions,Journal of Air Pollution Control Association,1975,25(2):168～172
[50] 徐学基,诸定昌,气体放电物理,上海:复旦大学出版社,1995
[51] Dhali S K,Williams P F,Two-dimensional studies of streamers in gases,Journal of Applied Physics,1987,62(12):4696～4707
[52] Kulikovsky A A,Three-dimensional simulation of a positive streamer in air near curved anode,Physics Letters A,1998,24(5): 445～452
[53] Gallimberti I,Recent advancements in the physical modeling of electrostatic precipitators,Journal of Electrostatics,1998,43 (4):219～247
[54] 向晓东,流体中污染物对轴对称物体的扩散模型及其简化研究,安全与环境学报,2004,4(4):66～69
[55] 肖福春,张国权,静电除尘器中紊流掺混系数的研究,南方冶金学院学报,1993,10(3):7～14
[56] Friedlander S K 著,烟、尘、和霾,常乐丰译,北京:科学出版社,1983
[57] 林肇信,大气污染控制工程,北京:高等教育出版社,1991
[58] 赵钟鸣,幸福堂,赵宏,一种计算电除尘器效率的半经验方法,建筑热能通风空调,1996,15(2):1～7
[2] 赵振奇,梁学邈,工业企业粉尘控制工程综合评价,北京:冶金工业出版社,2002
[3] 崔九思,室内空气污染监测方法,北京:化学工业出版社,2002
[4] 闫艳,张士强,赵国华等,某煤矿 1964～1995 年间尘肺发病情况的分析,河南预防医学杂志,2005,13(3):158～159
[5] 周振起,张炳文,输煤系统粉尘污染治理技术,环境污染治理技术与设备,2005,6(6):64～66
[6] Biswas P,Wu C,Nanoparticles and the environment,Journal of the Air & Waste Management Association,2005,55(3):708～746
[7] 向晓东,现代除尘理论与技术,北京:冶金工业出版社,2002
[8] 吴忠标,李伟,王莉红,城市大气环境概论,北京:化学工业出版社,2003
[9] 熊振湖,费学宁,池勇志等,大气污染防治技术及工程应用,北京:机械工业出版社,2003
[10] 姜安玺,气体污染控制,北京:化学工业出版社,2003
[11] 童志权,工业废气净化与利用,北京:化学工业出版社,2001
[12] 王显龙,何立波,贾明生等,静电除尘器的新应用及其发展方向,工业安全与环保,2003,29(11):3～6
[13] Fuchs N A,Mechanics of Aerosol,New York:Pergamon Press,1964
[14] Eliasson B,Miller J,Coagulation of bipolarly charged aerosols in a stack coagulator,Journal of Aerosol Science,1987,18(3): 869～872
[15] Williams M M ,Loyalka S K, Aerosol Science Theory and Practice,New York:Pergamon Press,1991
[16] Watanabe T,Tochikubo F,Koizumi Y,et al.,Submicron particle agglomeration by an electrostatic agglomerator,Journal of Electrostatics,1995,34(4):367～383
[17] Kauppinen E I,Maenhaut W,Lind T,Electrical combustion aerosol agglomeration, Journal of Aerosol Science,1993,24(1):11～12
[18] Hautanen J,Kilpelainen M,Kauppinen E,et al.,Electrical agglomeration of aerosol particles in an alternating electric field,Aerosol Science and Technology,1993,22(2):181～189
[19] Xiang X D,Colbeck I,Coagulation and wall loss of charged particles,Journal of Aerosol Science,1993,24(3):135～136
[20] Kanazawa S,Ohkuho T,Nomoto Y,Submicron particle agglomeration and precipitation by using a bipolar charging method,Journal of Electrostatics,1993,23(5):193～209
[21] Gutsch A,Loffer F,Electrically enhanced agglomeration of nanosized aerosol,Journal of Aerosol Science,1994,25(3):307～308
[22] Koizumi Y,Tochikubo F,Watanabe T,et al.,Bipolar-charged submicron particle agglomeration,Journal of Electrostatics, 1995,35(1):55～60
[23] Vemury S,Jansen C,Pratsinis S E,Coagulation of symmetric and asymmetric bipolar aerosol,Journal of Aerosol Science,1997, 28(4):599～611
[24] 向晓东,电凝并理论及在除尘应用中的新进展,通风除尘,1994,13 (4):28～31
[25] Lehtinen K,Jokiniemi J,Kauppinen E,Kinematic coagulation of charged droplets in an alternating electric field,Aerosol Science and Technology,1995,23(4):422～430
[26] Kildes J,Bhatia V K,Lind J,et al.,An experimental investigation for agglomeration of aerosols in alternating electric field,Aerosol Science and Technology,1995,23(4):603～610
[27] Laiainen A,Hautanen J,Keskinen J,et al.,Bipolar charged aerosol agglomeration with alternating electric field in laminar gas flow,Jouranl of Electrostatics,1996,38(4):303～315
[28] 向晓东,陈宝智,张国权,荷电粉尘在交变电场中的凝并与收集,东北大学学报,1999,20(6):615～617
[29] 陈旺生,向晓东,幸福堂,交变电场频率对电凝并影响的理论及实验研究,武汉冶金科技大学学报,1999,22(4):342～344
[30] Ji J H,Hwang J,Bae G N,Particle charging and agglomeration in DC and AC electic fields, Jouranl of Electrostatics,2004,61 (1):57～68
[31] Xiang X D,Colbeck I,Charged water dorps and smoke dissipation, Fire Safety Jouranl,1997,28(2):227～232
[32] 向晓东,陈旺生,幸福堂等,烟尘在交变电场中的电凝并收集,武汉冶金科技大学学报,1999,22(3):252～255
[33] 向晓东,陈旺生,幸福堂等,交变电场中电凝并收尘理论与实验研究,环境科学学报,2000,20(2):187～191
[34] 白敏冬,张芝涛,储金宇等,电离放电特征参量时空演变规律及其除尘应用的基础研究,中国基础科学,2006,8(2):14～19
[35] 陈旺生,向晓东,幸福堂,交变电场中偶极荷电粒子电凝并的理论研究,工业安全与防尘,2001,27(2):3～5
[36] Koizumi Y,Kawamura M,Tochikubo F,et al.,Estimation of the agglomeration coefficient of bipolar charged aerosol particles,Journal of Electrostatics,2000,48(2):93～101
[37] Yamamoto T,Ramanathan K,Lawless P,et al.,Control of volatile organic compounds by an ac energized ferroelectric pellet reactor and a pulsed corona reactor,IEEE Transactions Industry Application,1992,28(3):528～534
[38] Nunez C M,Ramsey G H,Ponder W H,et al.,Corona destruction: an innovative control technology for VOCs and air toxics,Air Waste,1993,43(2):242～247
[39] Nozaki T,Unno Y,Miyazaki Y,et al.,A clear distinction of plasma structure between APG and DBD.15th International Symposium on Plasma Chemistry,Orleans-France,2001,1:77～83
[40] 许德玄,静电除尘预荷电的研究,环境工程,1997,15(6):25～28
[41] Yao S,Zhang X,Lu B,Influence of plasma reactor structure on methanol oxidation,AIChE Journal,2005,51(5):1558～1564
[42] Seok J P,Sang S K,Effects of particle space charge and turbulent diffusion on performance of plate-plate electrostatic precipitators,Jouranl of Electrostatics,1998,45(2):121～137
[43] Zhang X,Wang L,Zhu K,An analysis of a wire-plate electrostatic precipitator,Journal of Aerosol Science,2002,33(11):1595 ～1600
[44] Laskin A,Cowin J P,On deposition efficiency of point-to-plate electrostatic precipitator, Journal of Aerosol Science,2002,33(3):405～409
[45] Yao S,Okumoto M,Yashima T,et al.,Diesel Praticulate Matter and NOx Removals Using a Pulsed Corona Surface Discharge, AIChE Journal,2004,50(3):715～721
[46] Yao S,Okumoto M,Madokoro K,et al.,A pulsed dielectric barrierdischarge reactor for diesel particulate matter removal, AIChE Journal,2004,50(8):1901～1907
[47] 吴彦,王荣毅,王宁会,脉冲电压下粒子荷电的实验研究,大连理工大学学报,1995,35(3):309～311
[48] Martin C,Air Pollution control theory,New York:McGraw-Hill Book Company,1976
[49] Smith W B,McDonald R,Calulation of the charging Rate of fine particles by unipolar ions,Journal of Air Pollution Control Association,1975,25(2):168～172
[50] 徐学基,诸定昌,气体放电物理,上海:复旦大学出版社,1995
[51] Dhali S K,Williams P F,Two-dimensional studies of streamers in gases,Journal of Applied Physics,1987,62(12):4696～4707
[52] Kulikovsky A A,Three-dimensional simulation of a positive streamer in air near curved anode,Physics Letters A,1998,24(5): 445～452
[53] Gallimberti I,Recent advancements in the physical modeling of electrostatic precipitators,Journal of Electrostatics,1998,43 (4):219～247
[54] 向晓东,流体中污染物对轴对称物体的扩散模型及其简化研究,安全与环境学报,2004,4(4):66～69
[55] 肖福春,张国权,静电除尘器中紊流掺混系数的研究,南方冶金学院学报,1993,10(3):7～14
[56] Friedlander S K 著,烟、尘、和霾,常乐丰译,北京:科学出版社,1983
[57] 林肇信,大气污染控制工程,北京:高等教育出版社,1991
[58] 赵钟鸣,幸福堂,赵宏,一种计算电除尘器效率的半经验方法,建筑热能通风空调,1996,15(2):1～7