电磁抗垢强化传热技术的研究
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摘要
结垢一直是工业上一个普遍令人头痛的问题,结垢会减少有效容量、降低生产效率、消耗燃料,从而造成巨大的经济损失。据调查,仅美国发电厂每年因冷却塔水垢问题导致的经济损失就高达100万美元。而我国每年因水垢引起的机件报废,直接损失也达十多亿元,而且污垢问题严重时甚至会危及人机安全。因此,对结垢问题的研究至关重要。现有的化学清洗方法不仅污染环境,而且会大大降低设备的使用寿命。但使用电磁场来进行减垢、抗垢时却可以避免这些问题,因而这一技术始终是研究者关注的重点。
     本文仅从实验的角度来对电磁结垢、抗垢技术进行热态实验研究,概括起来,主要包括以下几项工作:
     1、在原有的电磁抗垢、减垢实验装置上增设了换热段。
     2、进行了系统检测实验,其中包括热态热平衡实验和单相管内强制对流换热实验,以便验证实验系统的可行性。
     3、通过改变磁场频率、实验介质硬度等过程参数从污垢热阻以及换热系数的角度来进行了实验研究和理论分析。实验结果表明:
     (1) 没有经过电磁处理时,污垢热阻随着时间的增加而增加,换热系数随着时间的增加而减小;一旦经过电磁场的处理,污垢热阻开始时仍呈上升趋势,经过一段时间以后,便逐渐下降,换热系数的变化与此正好相反,即在实验开始时呈下降趋势,后来逐渐上升;当实验时间延长时,发现污垢热阻及换热系数在实验开始时的变化趋势与前面的实验结果基本相同,但到后来,二者的数值则分别均趋于稳定。
     (2) 在其它实验条件不变的情况下,若仅改变电磁场的频率,发现当频率为700赫兹左右时除垢效果最佳。
    
     北京工业大学工学硕士学位论文
    一
     (3)在其它实验条件不变的情况下,发现污垢热阻随着硬度的增加而增
    力口。
     4、在循环实验中分别将经过电磁处理的污垢晶体和未经过电磁处理的污垢
    晶体在扫描电镜下进行观察和分析后发现,电磁抗垢技术的机理的本质在于电
    磁技术改变了污垢晶体的形态,即由结构致密型易结垢的霸石改变为结构松散
    型不易结垢的方解石,这一结论与冷态实验研究的结论一致。
Fouling is a difficult problem in the industry all the time, because it reduces effective capacity, decreases productivity, consumes the fuel and accordingly results in tremendous economic loss. It is investigated that the economic loss that fouling of cooling tower of power houses causes every year in the Unite States is one million dollar and the direct loss which work reject caused by scale every year in China induces is more ten hundred million. Furthermore, fouling even endangers the safety of people and machine. So it is very important to study descaling. However, the existing chemical cleanout not only causes pollution, but also reduces the nature life of equipments. Electronic anti-fouling technology does not bring these problems, so researchers give it more attention.
    This paper performs the thermal experiment about electronic anti-fouling. The primary work is as following.
    1 > A heat transfer test section is designed and established on the basis of the existing experimental device of Electronic Anti-fouling .
    2> Some preparative experiments which include thermal balance experiments and forced convection heat transfer tests in the circular tube are done in order to validate the feasibility of the experimental system.
    3 ? We did the experiments and academic analysises from the point of view of fouling resistance and heat transfer coefficient by changing the coefficients such as the frequency of magnetic field, hardness of experimental liquid and so on. The experimental results are as follows:
    (1) Without EAF the fouling resistance increase along with addition of time
    
    
    
    and change of the heat transfer coefficient is just contrary to the result. However, with EAF fouling resistance still enhances at the beginning of experiment and later, it gradually minishes after experiment has started for some time. Of course, the change of heat transfer coefficient still is contrary to the outcome. But when experiment lasts longer time, fouling resistance and heat transfer coefficient change in the same trend as the fore results at the beginning of the experiment. However, They all go to the tranquilization until the last.
    (2) Under the same experimental condition as ever but changing the frequency of magnetic field, we discover that descaling is the best when the frequency of magnetic field is 700 Hz.
    (3) Under the same experimental condition as ever but changing hardness of experimental liquid, we discover that fouling resistance reduces along with the increase of hardness of experimental liquid.
    4 According to the observation of scale specimen under a scanning electron microscope, we discover that the mechanism of electromagnetic anti-fouling is to change the shape of fouling crystal. In other words, harder and denser aragonite is changed into incompact calcite under the action of magnetic field. The conclusion is consistent with the past experimental results.
引文
1 R. Steinhagen, H. M. Steinhagen and K. Maani, Problems and Costs due to Heat Exchanger Fouling in New Zealand Industries. Heat Transfer Engineering. 1993,14(1)
    2 李朝绪.锅炉排污和水垢清除.天津科学技术出版社,1980:46~48
    3 陕西省锅炉改造小组与西安冶金建筑学院编著.锅炉水处理及分析.科学出版社,1980:227~229
    4 窦照英.水处理、防腐蚀和失效分析1000例.化学工业出版社,2000:237
    5 任建新.物理清洗.化学工业出版社,2000:191~200
    6 邓德成,范杰.锅炉基础知识.山东科学技术出版社,1980:209~216
    7 J.G. Leidenfrost, De Aguae Communis Nonnullis Quqlitatibus Tractatus,1756. Int. J. Heat Mass Transfer, 1966,9:1153~1166
    8 E.N. Sieder, Application of Fouling Factors in the Design of Heat Exchanger, Heat .Transfer, ASME, 1935:82~86
    9 Tubular Exchanger Manufactures Association, Standards of Tubular Exchanger Manufactures Association, TEMA, New York, 1941
    10 D.Q. Kern and R. E. Seaton, A Theoretical Analysis of Thermal Surface Fouling, Chem. Eng. Prog.,1959,4:258~262
    11 D.Q. Kern and R. E. Seaton, Surface Fouling: How to Limit, Br. Chem. Eng.1959,55(6):71~73
    12 D. Hasson, Rate of Decrease of Heat Transfer Due to Scale Deposition, Dechema-Monugraphien, 1962,47:233~253
    13 W.T. Reid, External Corrosion and Deposits: Boilers and Gas Turbine,
    
    American Elsevier, New York, 1971
    14 N. Epstein, Fouling in Heat Exchangers, Heat Transfer 1978-Proc. 6th IHTC, 1979,6:235-253
    15 Chunfu Fan and Young I. Cho . Microscopic Observation of Calcium Carbonate Particles: Validation of an Experimental Validation of an Electronic anti-fouling Technology. Int. Comm. Heat Transfer. 1998,24(6) :747-756
    16 Ralph L.Webba,*,Wei Lib.Fouling in Enhanced Tubes Using Cooling Tower Water Part I :long-term Fouling Data. International Journal of Heat and Mass Transfer .2000,43 :3567-3578
    17 Wei Lia,Ralph L.Webbb,*. Ralph L.Webba,*.Fouling in Enhanced Tubes Using Cooling Tower Water Part I: long-term fouling data. International Journal of Heat and Mass Transfer. 2000,43 :3579-3588
    18 Sheikholeslami.Composite Fouling of Heat Transfer Equipment in Aqueous Media-A Rewiew. Heat Transfer Engineering. 2000, 21: 34-42
    19 Won Tae Kim and Young I. Cho. Experimental Study of the Crystal Growth Behavior of CaCos Fouling Using a Microscope. Experimental Heat Transfer.2000,13:153-161
    20 Bipan Bansal, Xian Dong Chen et. Comparison of Crystallization Fouling in Plate and Double-Pipe Heat Exchangers. Heat Transfer Engineering. 2001, 22:13-25
    21 L.F.Melo and J. de D. R. S. Pinheiro. Fouling Tests: Equipment and Methods. In "Fouling in Heat Exchange Equiment". Eds., J.W. Suitor et al. 1984:43-49
    22 Cho, Young I. And Choi, Byung-Gap. Experimental Validation of Electronic Anti-fouling Technology with a Plate Heat Exchanger. Heat Transfer 1998. Proceedings of 11th IHTC .1998,6:23-28
    
    
    23 R. Sheikholeslami. Calcium Sulfate Fouling-Precipitation or Particulate: A Proposed Composite Model. Heat Transfer Engineering .2000,21:24-33
    24 C hunfu Fan and Young I. Cho .A new Electronic Anti-fouling Technology to Control Precipitation Fouling. National Heat Transfer Conference. ASME. 1997,12:183-188
    25 Young I. Cho, Ph. D. et. An Innovative Electronic Descaling Technology for Scale Prevention in a Chiller. SE-99-03-01
    26 Y.I. Cho ,* Chunfu Fan, Byung-Gap. Use of Electronic Anti-fouling Technology with Filtration to Prevent Fouling in a Heat Exchanger. International Journal of Heat and Mass Transfer .1998,41:2961-2966
    27 Young I. Cho ,* and Byung-Gap ChoI. Electronic Anti-fouling Technology to Mitigate Precipitation Fouling in Plate-and-frame Heat Exchangers. Int. J. Heat Mass Transfer. 1998,41(17) : 2265-2571
    28 Y. I. Cho ,* Byung-Gap ChoI. Validation of an Electronic Anti-fouling Technology in a Single-tube. International Journal of Heat and Mass Transfer. 1999,42:1491-1499
    29 Rong Liu and Young I.Cho .Combined Use of an Electronic Anti-fouling Technology and Brush Punching for Scale Removal in a Water-cooled Plain Tube. Experimental Heat Transfer. 1999,12:203-213
    30 Y. I. Cho ,Chunfu Fan, and Byung-Gap ChoI. Theory of Electronic Anti-fouling Technology to Control Precipitation Fouling in Heat Exchangers. Int. Comm. Heat Mass Transfer. 1997,24(6) :757-770
    31 Youg I. Cho*, Rong Liu. Control of Fouling in a Spirally-ribbed Water Chilled Tube with Electronic Anti-fouling Technology. International Journal of Heat and Mass Transfer. 1999,42:3037-3046
    
    
    32 Antje Bornhorst Qi Zhao et. Reduction of Scale Formation Under Pool Boiling Conditions by Ion Implantation and Magnetron Sputtering on Heat Transfer Surfaces. Heat Transfer Engineering. 1999,20(2):6~14
    33 Young I. Cho and Rong Liu et. Study of Scale-Removal Methods in a Double-Pipe Heat Exchanger. Heat Transfer Engineering. 2000,21:50~57
    34 J. Middis,S.T. Paul,H.M.Muller-Steinhanen et. Reduction of Heat TransferFouling by the Addition of Wood Pulp Fibers. Heat Transfer Engineering. 1998,19(2):36~43
    35 徐志明,孙灵芳等.波纹管污垢特性的实验研究+.中国工程热物理学会传热传质学学术会议.20003086:481-483
    36 杨善让,徐志明,王建国等.污垢热阻动态模拟自动监测装置及其应用.中国工程热物理学会传热传质学学术会议.20003085:409-411
    37 李淑琴,程永清.声化学法除垢研究.陕西化工.1997:22-25
    38 马驰.交变电磁场在水处理中的应用.实用节能技术.2001:30-32
    39 张凡,曾伟林.磁力除垢器在锅炉给水处理中的应用.江西能源.2001(1):15~16
    40 吕连春,刑德安.高频电子除垢设备在空调水系统中的应用.山东建材.2001,22(1):35~36
    41 周新良,李石湘,朱江.高频电磁场防垢技术在灰水回收管道上的应用.电力环境保护.2001,17(1):18~20
    42 杨庆华,何建波,马昕。电磁水处理.浙江工业大学学报.1999,27(3):228~232
    43 曹刚.高频电磁场无菌磁化水设备在空压机冷却水防垢中的应用.山东冶金.2000,22(1):65~66
    44 贾克欣.几种电磁水处理器的作用机理及其应用.给水排水.1999,25(8):65~67
    
    
    45 徐晓宙,罗融.高频电磁场对防水垢机理的实验研究.西安交通大学学报.1997,31(1):124~126
    46 秦济华,戴新民,温天顺.高频水处理仪在循环水系统中的应用.河南化工.1997,(5):17~18
    47 郭平,赵丹亚,磁化水在冷却循环和供暖系统中的应用研究.热能动力工程.1995,10(6):371~374
    48 陈小华.磁处理技术在火电场水处理方面的应用.江西电力.1995,19(3):39~40
    49 陶景光.磁化除垢的电镜研究.工业水处理.1994,14(6):21~22
    50 崔凤磊.高频电场磁化水在防垢、杀菌方面的研究.工业水处理.1997(17)6:20~21
    51 杨开.磁化水的制备、特性及应用.工业水处理.1994,14(3):13~16
    52 杨善让,徐志明.换热设备的污垢与对策.科学出版社.1995
    53 N. Epstein, Thinking about Heat Transfer Fouling; A5×5 Matrix, Heat Transfer Engineering, 1983,4(1):43~56
    54 D.H. Lister, Corrosion Products in Power Generating Systems, in "Fouling of Heat Transfer Equipment" Eds. Somerscales and Knudsen, Hemisphere Pub. Corp, 1981:135~200
    55 J.M. Bartlett, U. S. Atomic Energy Commission Report, BNWL 676, 1968,5
    56 D.H. Charlesworth, Research and Development Studies in Environmental Pollution in Reactor Cooling Systems, Nuclear Engineering-Part ⅩⅪ, Ed. R. H. Moen, Chem. Eng. Progress Symp. Series, Amer. Inst. Chem. Engrs. New York. 1970,66(104):21~30
    57 S.K. Beal, Deposition of Particles in Turbulent Flow on Channel or Pipe Walls, Nucl. Sci. Eng. 1970,40:1~11
    
    
    58 J. Taborek et al. Predictive Methods for Fouling Behavior, Chem. Eng.Prog. 1972,68(7):69~78
    59 C.E. Loo and J. Bridgwater, Progress in the Prevention of Fouling in industrial plant, Ed. A. M. Pritchard, Proc. of a Conference held at the University of Nottingham, Nottingham, England, 1981:1~3
    60 K.A. Burrill, The Deposition of Magnetite Particles from High Velocity Water Onto Isothermal Tubes, AECL-5308, 1977
    61 R.M. Hopkins and N. Epstein, Fouling of Heated Stainless Steel Tubes by a Flowing Suspension of Ferric Oxide in Water, 5th IHTC, 1974,2:180~184
    62 A.P. Watkinson and N. Epstein, Particulate Fouling of Sensible Heat Exchangers, Heat Transfer 1970 Proc. of 4th IHTC, 1970,1: 1~12
    63 王勤娜,施宝昌,王浩.工业循环冷却水缓蚀阻垢剂的发展状况.化工进展.2001(5):26~28
    64 周厚安.油气田开发中硫酸盐垢的形成及防垢剂和除垢剂研究与应用进展.石油与天然气化工.1999(28):212~217
    65 周开学,卢贵武,黄乔松.磁防垢机理研究现状与进展.石油大学学报(自然科学版).1999(23):109~112
    66 丁昭.磁化防垢机理及适用界限研究.科技通报.1997(13):378~382
    67 奴尔江.水的电、磁处理.中国给水排水.1998(14):39~41
    68 赵丹亚,郭平.磁化处理水防垢除垢机理探讨.云南工学院学报.1994(10):83~87
    69 克拉辛.磁化水[M].毛钜凡等译.北京:计量出版社.1982
    70 马伟等.磁场效应在水处理中的作用与研究[J].工业水处理.1997,17(6)1~3
    
    
    71 昌年.进入水处理的物理方法[J]物理.1993,22(6):22~25
    72 Cbikazumi 5.etal.Pbysics in High Magnetic Fields [M].Springer verlny. 1982
    73 Darvill M. Magnetic Water Treatment. Wat. Waste Treat .1993,40.
    74 Dobrevski I., Boneva M. and Bonev B. Semi-industrial experiments evaluating the effect of the magnetic treatment of cooling water in decreasing deposit formation Russian J. appl. Chem. 1993,66:422~425
    75 Won Tae Kim and Young I.Cho. Effect of Electronic Anti-fouling Treatment on Fouling Mitigation with Circulating Cooling-tower Water. Int. Comm. Heat Mass Transfer. 2001,28(5):671~681
    76 耿殿雨等.磁防蜡防垢机制分析——再谈磁致胶体效应[J].磁能应用技术.1990,(4):21~25
    77 张兆庆等.国内外生物磁学现状与发展[J].磁性材料及器件.1994,25(4):58~61
    78 房春晖.电解质溶液结构研究进展与前景[J].化学进展.1996,8(4):318~330
    79 陈金辉.电磁抗垢、减垢强化传热技术机理的实验研究.北京工业大学硕士学位论文.2000
    80 Frank M.White.Heat Transfer.ISBN 0-201-08324-8,1984
    81 杨世铭,陶文铨.传热学.高等教育出版社.1998
    82 林宗虎.工程测量技术手册.化学工业出版社.1997

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