重力式油水分离器中的流体力学研究
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摘要
CFD(计算流体力学)方法用于油水分离过程模拟是一项新技术,它可以模拟油水分离器内部流场的流动特性和油滴上浮的轨迹,从而为设计和优化油水分离器的结构,预测油水分离的效果提供有效的手段和方法。本文以重力式油水分离器作为CFD模拟的研究对象,主要从流场的稳定性和油滴在流场中的运动轨迹两个方面对其进行了研究。
首先,本文利用CFD模型模拟了油水分离器内部挡板、五种典型的入口构件、以及具有不同参数的孔板稳流构件对流场稳定性的影响,并对不同构件的影响作出了比较和分析。发现出口处挡板的安置应考虑其对流场均一性的影响; 在不需要强调预分离效果的时候应优先考虑使用类似下孔箱的进口形式; 而采用单孔板作为稳流构件的时候,孔隙率应在20%左右; 采用双孔板时,两板距离不应超过100mm,否则效果不会比单板好。同时,本文建立了反映该过程简化的物理模型和流体力学模型,并对油水分离过程进行了流体力学模拟。该模型在分散相(油相)含量较小的情况下,用单相的水来代替油水混合物,得到的模拟结果良好。
另外,本文在对油滴上浮理论分析的基础上,进行了重力式油水分离器油滴上浮运动轨迹的模拟。在模拟的过程中考查了油滴粒径分布、流速大小、颗粒群等因素对油水分离效果产生的影响。在此基础上,进一步得到了流场的矢量图和油滴上浮的运动轨迹,模拟结果表明随着流速的增加和油滴粒径的减小都会使油水分离效果显著地下降。
最后,对模拟结果和实验数据进行了对比,结果本文运用CFD模拟计算得到的模拟结果与实验结果吻合良好。
CFD is a new technology used in analyzing the oil/water separation process. Effective methods are provided by CFD to design and optimize the structures, value the flow characters of the flow field, and predict the effects of the separation. The aim was to research on the primary oil/water separation process. The uniformity of the flow field and the tracks of the oil particles were the research focuses. Firstly, several different configurations, such as the baffles, the different inlets, and the porous baffles, were simulated to value their influences on the flow field.
Then, the influences of these configurations were compared and analyzed. And the following conclusions were achieved. Some facts were found that due attention should be focused on the pattern of the baffles near the outlet; the down box with holes inlet should be first considered when there was no need to emphasize the capacity of the separation of the inlet configuration; a 20% free area porous baffle gave better uniformity compared to baffles having 5, 15, and 30% free areas; and two baffles were no more beneficial than a single baffle unless they were spaced closer than 100mm apart. In the simulation process, the physical and fluid dynamic models were set up and simplified, and some good results were achieved. Based on the models, good results could be achieved by substituting the water for the mixture when the dispersed phase was only a little fraction of the mixture.
Secondly, based on the academic analysis, the simulation results of the oil particle tracks in the flow field were achieved. In the simulation process, the factors such as the diameter of the oil particles, velocity magnitude of flow, and particle group were considered. Based on the CFD models, the flow field figures and the tracks of the particles were obtained. It could be found that the separation capability would be weaken by the increasing of the velocity or the reducing of the diameters of the oil particles.
At last, the simulation results were compared with the experimental data. And the experimental results agreed well with those simulated.
首先,本文利用CFD模型模拟了油水分离器内部挡板、五种典型的入口构件、以及具有不同参数的孔板稳流构件对流场稳定性的影响,并对不同构件的影响作出了比较和分析。发现出口处挡板的安置应考虑其对流场均一性的影响; 在不需要强调预分离效果的时候应优先考虑使用类似下孔箱的进口形式; 而采用单孔板作为稳流构件的时候,孔隙率应在20%左右; 采用双孔板时,两板距离不应超过100mm,否则效果不会比单板好。同时,本文建立了反映该过程简化的物理模型和流体力学模型,并对油水分离过程进行了流体力学模拟。该模型在分散相(油相)含量较小的情况下,用单相的水来代替油水混合物,得到的模拟结果良好。
另外,本文在对油滴上浮理论分析的基础上,进行了重力式油水分离器油滴上浮运动轨迹的模拟。在模拟的过程中考查了油滴粒径分布、流速大小、颗粒群等因素对油水分离效果产生的影响。在此基础上,进一步得到了流场的矢量图和油滴上浮的运动轨迹,模拟结果表明随着流速的增加和油滴粒径的减小都会使油水分离效果显著地下降。
最后,对模拟结果和实验数据进行了对比,结果本文运用CFD模拟计算得到的模拟结果与实验结果吻合良好。
CFD is a new technology used in analyzing the oil/water separation process. Effective methods are provided by CFD to design and optimize the structures, value the flow characters of the flow field, and predict the effects of the separation. The aim was to research on the primary oil/water separation process. The uniformity of the flow field and the tracks of the oil particles were the research focuses. Firstly, several different configurations, such as the baffles, the different inlets, and the porous baffles, were simulated to value their influences on the flow field.
Then, the influences of these configurations were compared and analyzed. And the following conclusions were achieved. Some facts were found that due attention should be focused on the pattern of the baffles near the outlet; the down box with holes inlet should be first considered when there was no need to emphasize the capacity of the separation of the inlet configuration; a 20% free area porous baffle gave better uniformity compared to baffles having 5, 15, and 30% free areas; and two baffles were no more beneficial than a single baffle unless they were spaced closer than 100mm apart. In the simulation process, the physical and fluid dynamic models were set up and simplified, and some good results were achieved. Based on the models, good results could be achieved by substituting the water for the mixture when the dispersed phase was only a little fraction of the mixture.
Secondly, based on the academic analysis, the simulation results of the oil particle tracks in the flow field were achieved. In the simulation process, the factors such as the diameter of the oil particles, velocity magnitude of flow, and particle group were considered. Based on the CFD models, the flow field figures and the tracks of the particles were obtained. It could be found that the separation capability would be weaken by the increasing of the velocity or the reducing of the diameters of the oil particles.
At last, the simulation results were compared with the experimental data. And the experimental results agreed well with those simulated.
引文
[1]李国珍,肖华,董守平,油水分离技术及其进展,油气田地面工程,2001,20(2):7～9
[2]陆耀军,王金昌,油水重力分离技术及其进展,油气田地面工程,1999,18(4):6～8
[3]王恩长,波纹斜板除油装置试验,油田设计,1979,1-2:61
[4]李国珍,肖华,董守平,油水分离技术及其进展,油气田地面工程,2001,20(2):7～9
[5]李健,褚良银,液液分离水力旋流器研究进展,化工装备技术,1998,19(5):43～48
[6]Martin Thew. Hydrocyclone redesign for liquid-liquid separation. The Chemical Engineer, 1986, (7,8):17~23
[7]Nezhati K, Thew M T. Aspects of the performance and scaling of hydrocyclones for use with light dispersions. In: Proc 3rd Int Conf on hydrocyclones, UK: Oxford. 1987, 167~179
[8]Schuberi M F, Skilbeck F, Walker H J. Liquid hydrocyclone separation systems. In: Proc 4th Int Confon Hydrocyclone, UK: Southampton, 1992: 275~293
[9]陆耀军,沈熊,周力行,液—液旋流分离管结构选型实验研究,清华大学学报(自然科学版),2001,41(11):26～30
[10]刘淼儿,冯叔初,李自力等,液液旋流器中粒径、流量和效率的关系,《化工装备技术》,2000,21(2):1～4
[11]赵立新,王尊策,蒋明虎,液液水力旋流器流场特性与分离特性研究(三)——水力旋流器径向速度测试方法,化工装备技术,1999,20(5):4～6
[12]王尊策,赵立新,李枫等,液油水力旋流器流场特性与分离特性研究(六)——结构参数对分离特性的影响,化工装备技术,2000,21(1):14～16
[13]赵立新,蒋明虎,液液水力旋流器流场特性与分离特性研究(七)——操作参数对分离特性的影响,化工装备技术,2000,21(2):5～8
[14]郑陵,杜英生,波纹板聚结法油水分离技术,油田地面工程,1994,13(2):1～3
[15]Hennessey P M.er al. Hydrocarbon Processing, 1995.74(11):107~124
[16]C-E Natco, Vertical Performax Treaters Breakthrough Improves Oil Recovery, Reduces Fuel Costs, 1984,1215-A1~A2
[17]C-E Natco, Rapid Sseparation of Water-in-Oil, 1984,1230-A2
[18]曹建树,李卫清,郑远扬,新型波纹板油水分离器分离性能研究,过滤与分离,2001,11(2):12～14
[19]赵春莉,采出水处理技术——采用重力型横向流板式分离器进行油、水定性分离的研究,国外油田工程,1998,22～24
[20]汪九山,符合聚丙烯聚结板油水分离器的研究:[硕士学位论文],天津; 天津大学,2002
[21]王良均,吴孟周,石油化工废水处理设计手册[M],北京:中国石化出版社,1997,136～138
[22]陈雷,祁佩时,王鹤立,聚结除油性能及机理的探讨,中国环境科学,2002,22(1):16～19
[23]佟庆理等,两相流动理论基础,北京:冶金工业出版社:1988
[24]戴干策,陈敏恒,化工流体力学,北京:化学工业出版社,1988
[25]Gayler, R., N. W. Robberts and H. R. C. Pratt, Liquid-Liquid Extracton: part IV, Trans. Inst. Chem. Eng., 31, 1953, P. 57
[26]Zuber, N., and J. Hench, Steady State and Transient Viod Fracton of Bubbling Systems and Their Operating Limits, General Electric Co. Report, No. 62GL100(1962)
[27]Zuber, N., and J. A. Findley, Average Volumetric Concentration in tow-phase Flow Systems, J. Heat Trans., 7, 1965, P. 453
[28]Ishii M., and N. Zuber, Drag Coefficient and relation Velocity in Bubble, Droplet or Particalate Flows, AICHEJ., 25(5); 1979, 843~855
[29]Kumar, A., and S. Hartland, Gravity Settling Liquid-Liquid Dispersions, The Can. J. of Chem. Eng., 63(3), 1985, 368~376
[30]Adrian, R. J., Multi-Point Optical Measurement of Simultaneous Vectors in Unsteady Flow-a Review, Int. J. Hc. J. Fluid Flow, 7(2), 1986, 127~145.
[31]Gray, C. and C. A. Greated, :The Application of Particle Image Velocimetry to Study of Water Waves, Opt. And Lasers in Eng, 9, 1988, p. 265
[32]Arroyo, M. P., et al., :Velocity Measurement in Convective Flows by Particale Image Velocimetry Using a low Power Laser,: Opt. Eng., 27(8), 1988, 641~649
[33]盛森芝等编,流速测量技术,北京:北京大学出版社,1987
[34]Szekely, J., Fluid Flow Phenomena in Metals Procesing, Academic-Press, 1979
[35]李鑫钢,斜板上液液聚结分相动力学研究:[博士学位论文],天津; 天津大学,1992
[36]董大勇,平板间液液分层流动速度分布及界面特性研究:[硕士学位论文], 天津; 天津大学,1997
[37]朱自强等,应用计算流体力学,北京:北京航空航天大学出版社,1998
[38]刘霞,葛新锋,FLUENT 软件及其在我国的应用,能源研究与利用,2003,2:36~38
[39]陶文铨,计算传热学的近代进展,北京:科学出版社,2000,390~395
[40]Gianluca Iaccarinno. Prediction of the turbulent flow in a diffuser with commercial CFD codes, p271~278, Annual Research Briefs 2000, Center for Turbulence Research, USA
[41]Gambit 2.0 User’s Guide. Fluent Inc.
[42]Fluent 5.0 User’s Guide. Volume 1~5, Fluent Inc.
[43]Drown D C. The fluid mechanics basis for the design criteria of gravity liquid-liquid settler[D]. Idaho University, 1975
[44]Wilkinson D, Waldie B. CFD and experimental studies of fluid and particle flow in horizontal primary separators [J]. TransⅠChem E, 1994, 72(Part A): 189-196.
[45]Zemel B, Bowman R W, Residence time distribution in gravity oil-water separators[J]. Journal of Petroleum Technology, 1978(February): 275-282.
[46]陆耀军,薛敦松,重力式油水分离设备流动特性研究,石油学报,2000,16(6):23-29.
[47]D.Wilkinson, B. Waldie, M.I. Mohamad Nor, Hsio Yen Lee, Baffle plate configuration to enhance separation in horizontal primary separators, Chemical Engineering Journal, Heriot-Watt University, 2000,77:221~226.
[48]陆耀军、潘玉琦,重力式油水分离设备中影响液滴运动的因素,油田地面工程,1993.6,12(3):1~5
[49]陆耀军,油水重力分离过程中的液滴动力学分析,油气田地面工程,1998.7,17(4):1~5
[50]陆耀军等,重力式油水分离设备入口构件的模拟实验优选,石油学报,1995,16(3):111~115
[51]罗进飞,波纹板填料轻烃脱水过程的研究:[硕士学位论文], 天津; 天津大学,2002
[2]陆耀军,王金昌,油水重力分离技术及其进展,油气田地面工程,1999,18(4):6～8
[3]王恩长,波纹斜板除油装置试验,油田设计,1979,1-2:61
[4]李国珍,肖华,董守平,油水分离技术及其进展,油气田地面工程,2001,20(2):7～9
[5]李健,褚良银,液液分离水力旋流器研究进展,化工装备技术,1998,19(5):43～48
[6]Martin Thew. Hydrocyclone redesign for liquid-liquid separation. The Chemical Engineer, 1986, (7,8):17~23
[7]Nezhati K, Thew M T. Aspects of the performance and scaling of hydrocyclones for use with light dispersions. In: Proc 3rd Int Conf on hydrocyclones, UK: Oxford. 1987, 167~179
[8]Schuberi M F, Skilbeck F, Walker H J. Liquid hydrocyclone separation systems. In: Proc 4th Int Confon Hydrocyclone, UK: Southampton, 1992: 275~293
[9]陆耀军,沈熊,周力行,液—液旋流分离管结构选型实验研究,清华大学学报(自然科学版),2001,41(11):26～30
[10]刘淼儿,冯叔初,李自力等,液液旋流器中粒径、流量和效率的关系,《化工装备技术》,2000,21(2):1～4
[11]赵立新,王尊策,蒋明虎,液液水力旋流器流场特性与分离特性研究(三)——水力旋流器径向速度测试方法,化工装备技术,1999,20(5):4～6
[12]王尊策,赵立新,李枫等,液油水力旋流器流场特性与分离特性研究(六)——结构参数对分离特性的影响,化工装备技术,2000,21(1):14～16
[13]赵立新,蒋明虎,液液水力旋流器流场特性与分离特性研究(七)——操作参数对分离特性的影响,化工装备技术,2000,21(2):5～8
[14]郑陵,杜英生,波纹板聚结法油水分离技术,油田地面工程,1994,13(2):1～3
[15]Hennessey P M.er al. Hydrocarbon Processing, 1995.74(11):107~124
[16]C-E Natco, Vertical Performax Treaters Breakthrough Improves Oil Recovery, Reduces Fuel Costs, 1984,1215-A1~A2
[17]C-E Natco, Rapid Sseparation of Water-in-Oil, 1984,1230-A2
[18]曹建树,李卫清,郑远扬,新型波纹板油水分离器分离性能研究,过滤与分离,2001,11(2):12～14
[19]赵春莉,采出水处理技术——采用重力型横向流板式分离器进行油、水定性分离的研究,国外油田工程,1998,22～24
[20]汪九山,符合聚丙烯聚结板油水分离器的研究:[硕士学位论文],天津; 天津大学,2002
[21]王良均,吴孟周,石油化工废水处理设计手册[M],北京:中国石化出版社,1997,136～138
[22]陈雷,祁佩时,王鹤立,聚结除油性能及机理的探讨,中国环境科学,2002,22(1):16～19
[23]佟庆理等,两相流动理论基础,北京:冶金工业出版社:1988
[24]戴干策,陈敏恒,化工流体力学,北京:化学工业出版社,1988
[25]Gayler, R., N. W. Robberts and H. R. C. Pratt, Liquid-Liquid Extracton: part IV, Trans. Inst. Chem. Eng., 31, 1953, P. 57
[26]Zuber, N., and J. Hench, Steady State and Transient Viod Fracton of Bubbling Systems and Their Operating Limits, General Electric Co. Report, No. 62GL100(1962)
[27]Zuber, N., and J. A. Findley, Average Volumetric Concentration in tow-phase Flow Systems, J. Heat Trans., 7, 1965, P. 453
[28]Ishii M., and N. Zuber, Drag Coefficient and relation Velocity in Bubble, Droplet or Particalate Flows, AICHEJ., 25(5); 1979, 843~855
[29]Kumar, A., and S. Hartland, Gravity Settling Liquid-Liquid Dispersions, The Can. J. of Chem. Eng., 63(3), 1985, 368~376
[30]Adrian, R. J., Multi-Point Optical Measurement of Simultaneous Vectors in Unsteady Flow-a Review, Int. J. Hc. J. Fluid Flow, 7(2), 1986, 127~145.
[31]Gray, C. and C. A. Greated, :The Application of Particle Image Velocimetry to Study of Water Waves, Opt. And Lasers in Eng, 9, 1988, p. 265
[32]Arroyo, M. P., et al., :Velocity Measurement in Convective Flows by Particale Image Velocimetry Using a low Power Laser,: Opt. Eng., 27(8), 1988, 641~649
[33]盛森芝等编,流速测量技术,北京:北京大学出版社,1987
[34]Szekely, J., Fluid Flow Phenomena in Metals Procesing, Academic-Press, 1979
[35]李鑫钢,斜板上液液聚结分相动力学研究:[博士学位论文],天津; 天津大学,1992
[36]董大勇,平板间液液分层流动速度分布及界面特性研究:[硕士学位论文], 天津; 天津大学,1997
[37]朱自强等,应用计算流体力学,北京:北京航空航天大学出版社,1998
[38]刘霞,葛新锋,FLUENT 软件及其在我国的应用,能源研究与利用,2003,2:36~38
[39]陶文铨,计算传热学的近代进展,北京:科学出版社,2000,390~395
[40]Gianluca Iaccarinno. Prediction of the turbulent flow in a diffuser with commercial CFD codes, p271~278, Annual Research Briefs 2000, Center for Turbulence Research, USA
[41]Gambit 2.0 User’s Guide. Fluent Inc.
[42]Fluent 5.0 User’s Guide. Volume 1~5, Fluent Inc.
[43]Drown D C. The fluid mechanics basis for the design criteria of gravity liquid-liquid settler[D]. Idaho University, 1975
[44]Wilkinson D, Waldie B. CFD and experimental studies of fluid and particle flow in horizontal primary separators [J]. TransⅠChem E, 1994, 72(Part A): 189-196.
[45]Zemel B, Bowman R W, Residence time distribution in gravity oil-water separators[J]. Journal of Petroleum Technology, 1978(February): 275-282.
[46]陆耀军,薛敦松,重力式油水分离设备流动特性研究,石油学报,2000,16(6):23-29.
[47]D.Wilkinson, B. Waldie, M.I. Mohamad Nor, Hsio Yen Lee, Baffle plate configuration to enhance separation in horizontal primary separators, Chemical Engineering Journal, Heriot-Watt University, 2000,77:221~226.
[48]陆耀军、潘玉琦,重力式油水分离设备中影响液滴运动的因素,油田地面工程,1993.6,12(3):1~5
[49]陆耀军,油水重力分离过程中的液滴动力学分析,油气田地面工程,1998.7,17(4):1~5
[50]陆耀军等,重力式油水分离设备入口构件的模拟实验优选,石油学报,1995,16(3):111~115
[51]罗进飞,波纹板填料轻烃脱水过程的研究:[硕士学位论文], 天津; 天津大学,2002