城市污水污泥转筒式直接干化研究
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摘要
随着城市的发展,污水污泥对环境的污染问题越来越凸现出来。污泥混合焚烧或干化焚烧等处理效果非常彻底的方法逐渐成为污泥处理的主流技术。在众多的污泥热处理方法中,转筒式干燥法由于设备构造简单、运行调节方便、处理效果好等优点,非常适合我国目前的国情。因此自行设计了污泥转筒式直接干燥机及给料机、热风炉等各种配套设备,以燃烧天然气得到的高温烟气为热源对污泥转筒式直接干化技术进行了研究。
试验设备可将原本含水率为80%左右的湿污泥干化到含水20～40%,每小时处理量可达50kg/h;转筒整体的水平倾角可调,转筒转速可调,转筒干燥机筒体轴心处有搅拌轴且转速可调,给料机可调节给料速度且保持给料速度稳定。以含水率大小为评判标准,可对上述参数进行组合得到各种工况以研究各参数对含水率的影响。试验结果表明,在不同的水平倾角下,含水率均随着搅拌轴转速的增大而减小,随着给料速度的增大而增大;当水平倾角为5°时,含水率随着转筒转速的增大先减小后增大,即存在一个最佳转速使含水率达到最低。之后又更换了一种污泥重复上述的试验,试验结果依然符合上述的规律,表明本试验设备对于处理不同种类的污泥具有很好的适应性。
由于无法对干化污泥颗粒粒径、污泥停留时间、转筒式干燥机出口烟温等重要参数进行准确的试验测量。因此,利用计算机语言并结合相关的数学方法建立了数学模型,对干燥设备进行数值模拟。通过比较试验结果和计算结果后得出,在转筒转速和给料速度对含水率的影响方面,两种结果显示的规律性非常相似;得到的粒径数据也非常接近试验的近似测量值。在研究不同转速(不同给料速度)对含水率的影响时,不同转速(不同给料速度)下的曲线具有清晰的规律一致性,由此可以断定当转速(给料速度)处于某个试验为涉及的中间值时,其影响情况也符合已知的规律。同时还获得了很多无法用试验来验证的工况下的干化结果数据。
不足之处是出口烟温的试验测量值和数值计算值差异比较大,其原因是多方面的。由于理论知识的限制,未能为搅拌轴建立相应的模型,这一差异可能是造成某些数据误差较大的重要原因。
Along with the development of modern city, municipal sewage sludge becomes more and more harmful to the environment. The main and most popular methods currently are“drying-combustion”or“mixed combustion”methods. Rotary drying was wildly applied in developed countries in their early disposal periods, so it is the suitable method for the practical situation of China. So we design the rotary drier, sludge feeder, air heating furnace and other auxiliary devices and dry the sludge in rotary drier by hot flue gas which gotten by burning natural gas.
The drying devices designed by ourselves can deal 50kg sludge(moisture is 80%) per hour, the moisture of the dry sludge are 20%~40%; the horizontal obliquity is alterable, the rotate speed of mixer shaft in the center of the rotate drier and the rotary drier are alterable; the speed of feeding sludge is also alterable. Setting the moisture as the assessing standard and combining the parameters mentioned above, we carried out the pilot test. The results of the test indicated that moisture decreased with the increasing of mixed shaft’s rotate speed, decreased with the increasing of feeding sludge speed; when the horizontal obliquity is 5°, moisture decreased and then increased with the speed of rotary drier’s increasing, it means a optimal speed under which moisture could be lowest is existed; when the horizontal obliquity is 2.5°, moisture decreased continuously with the increasing of rotary drier’s speed. After the pilot test, we changed another kind of sludge and repeated the process above and then got the similar discipline. It indicated that the device we designed has an excellent suitability to different kinds of sludge.
For the limitation of the test condition, we can’t research more parameters, for example, the dry sludge grain size, average remaining time, the outlet temperature of drier outlet and so on. So by utilizing the computer languages and interrelated mathematics knowledge, we completed a mathematical model to simulate the rotary drier and compared the calculating results with the test results. The comparison showed that the relationship of moisture and rotary drier and feeding sludge speed the calculating results gave were very similar with the test results gave. We got the proper grain size of dry sludge at the same time. The most obvious difference between the tow results came from outlet temperature. This result was caused by many reasons, and the main reason may be that we failed to simulate the mixed shaft which is significant to the moisture in the model for limitation of the model theory.
试验设备可将原本含水率为80%左右的湿污泥干化到含水20～40%,每小时处理量可达50kg/h;转筒整体的水平倾角可调,转筒转速可调,转筒干燥机筒体轴心处有搅拌轴且转速可调,给料机可调节给料速度且保持给料速度稳定。以含水率大小为评判标准,可对上述参数进行组合得到各种工况以研究各参数对含水率的影响。试验结果表明,在不同的水平倾角下,含水率均随着搅拌轴转速的增大而减小,随着给料速度的增大而增大;当水平倾角为5°时,含水率随着转筒转速的增大先减小后增大,即存在一个最佳转速使含水率达到最低。之后又更换了一种污泥重复上述的试验,试验结果依然符合上述的规律,表明本试验设备对于处理不同种类的污泥具有很好的适应性。
由于无法对干化污泥颗粒粒径、污泥停留时间、转筒式干燥机出口烟温等重要参数进行准确的试验测量。因此,利用计算机语言并结合相关的数学方法建立了数学模型,对干燥设备进行数值模拟。通过比较试验结果和计算结果后得出,在转筒转速和给料速度对含水率的影响方面,两种结果显示的规律性非常相似;得到的粒径数据也非常接近试验的近似测量值。在研究不同转速(不同给料速度)对含水率的影响时,不同转速(不同给料速度)下的曲线具有清晰的规律一致性,由此可以断定当转速(给料速度)处于某个试验为涉及的中间值时,其影响情况也符合已知的规律。同时还获得了很多无法用试验来验证的工况下的干化结果数据。
不足之处是出口烟温的试验测量值和数值计算值差异比较大,其原因是多方面的。由于理论知识的限制,未能为搅拌轴建立相应的模型,这一差异可能是造成某些数据误差较大的重要原因。
Along with the development of modern city, municipal sewage sludge becomes more and more harmful to the environment. The main and most popular methods currently are“drying-combustion”or“mixed combustion”methods. Rotary drying was wildly applied in developed countries in their early disposal periods, so it is the suitable method for the practical situation of China. So we design the rotary drier, sludge feeder, air heating furnace and other auxiliary devices and dry the sludge in rotary drier by hot flue gas which gotten by burning natural gas.
The drying devices designed by ourselves can deal 50kg sludge(moisture is 80%) per hour, the moisture of the dry sludge are 20%~40%; the horizontal obliquity is alterable, the rotate speed of mixer shaft in the center of the rotate drier and the rotary drier are alterable; the speed of feeding sludge is also alterable. Setting the moisture as the assessing standard and combining the parameters mentioned above, we carried out the pilot test. The results of the test indicated that moisture decreased with the increasing of mixed shaft’s rotate speed, decreased with the increasing of feeding sludge speed; when the horizontal obliquity is 5°, moisture decreased and then increased with the speed of rotary drier’s increasing, it means a optimal speed under which moisture could be lowest is existed; when the horizontal obliquity is 2.5°, moisture decreased continuously with the increasing of rotary drier’s speed. After the pilot test, we changed another kind of sludge and repeated the process above and then got the similar discipline. It indicated that the device we designed has an excellent suitability to different kinds of sludge.
For the limitation of the test condition, we can’t research more parameters, for example, the dry sludge grain size, average remaining time, the outlet temperature of drier outlet and so on. So by utilizing the computer languages and interrelated mathematics knowledge, we completed a mathematical model to simulate the rotary drier and compared the calculating results with the test results. The comparison showed that the relationship of moisture and rotary drier and feeding sludge speed the calculating results gave were very similar with the test results gave. We got the proper grain size of dry sludge at the same time. The most obvious difference between the tow results came from outlet temperature. This result was caused by many reasons, and the main reason may be that we failed to simulate the mixed shaft which is significant to the moisture in the model for limitation of the model theory.
引文
[1]郭淑琴,孙孝然,几种国外城市污水处理厂污泥干化技术及设备介绍,给水排水,Vol. 30 No.6 2004
[2]张水英,陈子庭,黄鸥,增钙干化污泥技术再生利用,建设科技, 2007年23期60～61
[3] P. J. MA'ITHEWS, CChem, FRSC, Sewage Sludge Disposal in the UK: A New Challenge for the Next Twenty Years[J], J.IWEM, 1992, 6, October.
[4]王璠,柯尊忠,田秀敏,城市污泥干化技术研究,机电产品开发与创新,2003年第2期
[5] J. E. HALL, Sewage Sludge Production, Treatment and Disposal in the European Union, J.CIWEh4, 1995,9, August
[6]韩晓强,陈晓平,上海石洞口干化污泥焚烧炉的调试,锅炉技术,2006年1月第37卷第1期,77～80
[7]熊孟清,张立民,城市污水处理厂污泥与煤在工业锅炉内的混烧,上海电力学院学报[J],2004年02期
[8]邱天,张衍国,吴占松,城市污水污泥燃烧特性试验研究,热力发电[J],2003年第三期
[9] R.D.Davis, E.B.Glennie, J.A.Hobson, MA and D.Sivil, Environmental Implications of Incineration and other Advanced Sludge Treatment Process, Water and Environment Journal, Volume 16, Issue 3, Page 157-163, Aug 2002
[10]胡龙,何品晶,邵立明.城市污水厂污泥热干燥处理技术及其应用分析[J],重庆环境科学, 1999(01)
[11] Miloslav Hartman, Michael Pohorely, Otakar Trnka, Fluidization of Dried Wasterwater Sludge, Powder Technology 178(2007) 166-172
[12]翁焕新,马学文,苏闽华,利用烟气余热干化城市污泥工艺的应用,中国给水排水,2008年2月第24卷第4期,58～61
[13]沈环轩,刘晓东,常州污泥焚烧模式“开花结果”,江苏经济报,2007年3月3日第A01版
[14]刘琳,天津市咸阳路污水厂的污泥脱水与干化处理设计,中国给水排水,2007年7月第23卷第14期,56～58
[15]胡大卫,赖参森,郭淑琴,天津市东部污水处理厂污泥干化和资源化方案,中国给水排水,2006年10月第22卷第20期,38～40
[16]罗柏华,高广忠,污水厂污泥快速干化焚烧及制肥新工艺,环境工程,2006年10月第24卷第5期,64～66
[17]刘静,符超军,梁艳华,广州每天处理污泥近千吨,南方日报2006年3月14日第B01版
[18]王钊,北京污水处理厂污泥干化处理工艺选择的探讨[J],市政技术,2004年11月第22卷第6期,374～378
[19]杨小文,杜英豪,国外污泥干化技术进展,给水排水,Vol.28 No.2 2002,35～36
[20] Hall J E, The need for Innovation in Sludge Treatment and Disposal, Proceedings Symposium on Innovation Technologies for Sludge Utilization and Disposal, 1994.UK
[21]郭淑琴,孙孝然,几种国外城市污水处理厂污泥干化技术及设备介绍,给水排水, 2004年06期, 34～37
[22]朱南文,徐华伟,国外污泥热干燥技术,给水排水,Vol.28 No.1 2002
[23]黄凌军,杜红等,欧洲污泥干化焚烧处理技术的应用与发展趋势,给水排水,Vol.29 No.11 2003
[24] T. S. C. GROSS, BSc, CEng, DipEM, MICE, Thermal drying of sewage sludge, Water and Environment Journal, Volume 7, Issue 3, Jun 1993, 255-261
[25] EPA. Process design manual for sludge treatment and disposal. Center for environmental research information technology transfer. USA, 1979
[26] Brouwillette F, M Sain, C Daneault. Effect of moisture profile and noncombustible matter in recycled paper mill sludge on energy recovery. Combustion Science Technology, 1998, 139(1): 191-206
[27] Miloslav Hartman, Michael Pohorely, Otakar Trnka, Fluidization of Dried Wasterwater Sludge, Powder Technology 178(2007) 166-172
[28] H.Henein,J.Brimacombe,A.P.Watkinson,Experimental study of transverse bed motion in rotary kiln[J].Metall:Trans.B,14B(1983)191-204.
[29] S.J.Porter,The design of rotary driers and coolers[J].Trans.Instn.Chem,41(1963)272-280.
[30] D. W.Pershing,J.S.Lighty,et.Solid Waste Incineration in Rorary Kilns[J].Combust.Sci.Technol,93(1993):245-276.
[31]李水清.固体废物热解制取洁净燃料和化学原料的基础研究[D].浙江:浙江大学机械与能源工程学院,2002.4
[32] Wen-Ching Yang.Dynamics of simulated municipal solid waste in a rolating devic [M].Powder Technology.72(1992):139-147
[33] Bordasch, H.W, Cost reduction by rotary sludge drying[M], Galvanotechnik, v 85, n 11, Nov, 1994, p 3655-3657
[34] A.A.Boateng.On flow-induced kinetic diffusion and rotary kiln bed burden heat transport[J].Chem Eng.Comm.170(1998):51-66
[35] L.Yang and B,Farouk.Modeling of solid particle flow and heat transfer in rotarykiln[J].Journal of the Air Waste Management Association.47(1997):1189-1196.
[36] P.S.Ghoshdastidar,V.K,Anandan Unni.Heat transfer in the non-reacting zone of cement rotary kiln[J].Journal of Engineering for Industry.Trans of ASME.118(1996):169-172
[37] D.Tolmac,M.Lambic.The mathematical model of the temperature field of the rolating cylinder for the contact dryer[J].Int.Comm.Heat Mass Transfer.26(1999):579-586
[38] Xiao Yan Liu,Eckehard Specht.Mean residence time and hold-up of solids in rotary kilns[J].Chemical Engineering Science 61(2006):5176-5181.
[39]杨微,Fortran语言程序设计[M].辽宁:大连理工大学出版社,2006:20～178
[40] P. LOWE, FRSC, MBIM, Developments in the Thermal Drying of Sewage Sludge[J], JCIWEM, 1995,9, June
[41] M. J. BROWN, BTech, CEng, Development of the Sludge Thermal-Drying Option for South West Water[J], JCIWEM, 1995,9, October
[42]杨世铭,陶文铨.传热学[M].北京:高等教育出版社,2006
[43]周校平,张晓男.燃烧理论基础[M].上海:上海交通大学出版社,2000:7～12
[44]沈维道,蒋智敏,童钧耕等.工程热力学[M].北京:高等教育出版社,2001:343～344
[2]张水英,陈子庭,黄鸥,增钙干化污泥技术再生利用,建设科技, 2007年23期60～61
[3] P. J. MA'ITHEWS, CChem, FRSC, Sewage Sludge Disposal in the UK: A New Challenge for the Next Twenty Years[J], J.IWEM, 1992, 6, October.
[4]王璠,柯尊忠,田秀敏,城市污泥干化技术研究,机电产品开发与创新,2003年第2期
[5] J. E. HALL, Sewage Sludge Production, Treatment and Disposal in the European Union, J.CIWEh4, 1995,9, August
[6]韩晓强,陈晓平,上海石洞口干化污泥焚烧炉的调试,锅炉技术,2006年1月第37卷第1期,77～80
[7]熊孟清,张立民,城市污水处理厂污泥与煤在工业锅炉内的混烧,上海电力学院学报[J],2004年02期
[8]邱天,张衍国,吴占松,城市污水污泥燃烧特性试验研究,热力发电[J],2003年第三期
[9] R.D.Davis, E.B.Glennie, J.A.Hobson, MA and D.Sivil, Environmental Implications of Incineration and other Advanced Sludge Treatment Process, Water and Environment Journal, Volume 16, Issue 3, Page 157-163, Aug 2002
[10]胡龙,何品晶,邵立明.城市污水厂污泥热干燥处理技术及其应用分析[J],重庆环境科学, 1999(01)
[11] Miloslav Hartman, Michael Pohorely, Otakar Trnka, Fluidization of Dried Wasterwater Sludge, Powder Technology 178(2007) 166-172
[12]翁焕新,马学文,苏闽华,利用烟气余热干化城市污泥工艺的应用,中国给水排水,2008年2月第24卷第4期,58～61
[13]沈环轩,刘晓东,常州污泥焚烧模式“开花结果”,江苏经济报,2007年3月3日第A01版
[14]刘琳,天津市咸阳路污水厂的污泥脱水与干化处理设计,中国给水排水,2007年7月第23卷第14期,56～58
[15]胡大卫,赖参森,郭淑琴,天津市东部污水处理厂污泥干化和资源化方案,中国给水排水,2006年10月第22卷第20期,38～40
[16]罗柏华,高广忠,污水厂污泥快速干化焚烧及制肥新工艺,环境工程,2006年10月第24卷第5期,64～66
[17]刘静,符超军,梁艳华,广州每天处理污泥近千吨,南方日报2006年3月14日第B01版
[18]王钊,北京污水处理厂污泥干化处理工艺选择的探讨[J],市政技术,2004年11月第22卷第6期,374～378
[19]杨小文,杜英豪,国外污泥干化技术进展,给水排水,Vol.28 No.2 2002,35～36
[20] Hall J E, The need for Innovation in Sludge Treatment and Disposal, Proceedings Symposium on Innovation Technologies for Sludge Utilization and Disposal, 1994.UK
[21]郭淑琴,孙孝然,几种国外城市污水处理厂污泥干化技术及设备介绍,给水排水, 2004年06期, 34～37
[22]朱南文,徐华伟,国外污泥热干燥技术,给水排水,Vol.28 No.1 2002
[23]黄凌军,杜红等,欧洲污泥干化焚烧处理技术的应用与发展趋势,给水排水,Vol.29 No.11 2003
[24] T. S. C. GROSS, BSc, CEng, DipEM, MICE, Thermal drying of sewage sludge, Water and Environment Journal, Volume 7, Issue 3, Jun 1993, 255-261
[25] EPA. Process design manual for sludge treatment and disposal. Center for environmental research information technology transfer. USA, 1979
[26] Brouwillette F, M Sain, C Daneault. Effect of moisture profile and noncombustible matter in recycled paper mill sludge on energy recovery. Combustion Science Technology, 1998, 139(1): 191-206
[27] Miloslav Hartman, Michael Pohorely, Otakar Trnka, Fluidization of Dried Wasterwater Sludge, Powder Technology 178(2007) 166-172
[28] H.Henein,J.Brimacombe,A.P.Watkinson,Experimental study of transverse bed motion in rotary kiln[J].Metall:Trans.B,14B(1983)191-204.
[29] S.J.Porter,The design of rotary driers and coolers[J].Trans.Instn.Chem,41(1963)272-280.
[30] D. W.Pershing,J.S.Lighty,et.Solid Waste Incineration in Rorary Kilns[J].Combust.Sci.Technol,93(1993):245-276.
[31]李水清.固体废物热解制取洁净燃料和化学原料的基础研究[D].浙江:浙江大学机械与能源工程学院,2002.4
[32] Wen-Ching Yang.Dynamics of simulated municipal solid waste in a rolating devic [M].Powder Technology.72(1992):139-147
[33] Bordasch, H.W, Cost reduction by rotary sludge drying[M], Galvanotechnik, v 85, n 11, Nov, 1994, p 3655-3657
[34] A.A.Boateng.On flow-induced kinetic diffusion and rotary kiln bed burden heat transport[J].Chem Eng.Comm.170(1998):51-66
[35] L.Yang and B,Farouk.Modeling of solid particle flow and heat transfer in rotarykiln[J].Journal of the Air Waste Management Association.47(1997):1189-1196.
[36] P.S.Ghoshdastidar,V.K,Anandan Unni.Heat transfer in the non-reacting zone of cement rotary kiln[J].Journal of Engineering for Industry.Trans of ASME.118(1996):169-172
[37] D.Tolmac,M.Lambic.The mathematical model of the temperature field of the rolating cylinder for the contact dryer[J].Int.Comm.Heat Mass Transfer.26(1999):579-586
[38] Xiao Yan Liu,Eckehard Specht.Mean residence time and hold-up of solids in rotary kilns[J].Chemical Engineering Science 61(2006):5176-5181.
[39]杨微,Fortran语言程序设计[M].辽宁:大连理工大学出版社,2006:20～178
[40] P. LOWE, FRSC, MBIM, Developments in the Thermal Drying of Sewage Sludge[J], JCIWEM, 1995,9, June
[41] M. J. BROWN, BTech, CEng, Development of the Sludge Thermal-Drying Option for South West Water[J], JCIWEM, 1995,9, October
[42]杨世铭,陶文铨.传热学[M].北京:高等教育出版社,2006
[43]周校平,张晓男.燃烧理论基础[M].上海:上海交通大学出版社,2000:7～12
[44]沈维道,蒋智敏,童钧耕等.工程热力学[M].北京:高等教育出版社,2001:343～344
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