FCC沉降器内不同结构旋风分离系统的模拟分析
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摘要
FCC沉降器内两级旋风分离系统是石油工业催化裂化过程的重要组成部分。为了分析两级旋风分离系统之间的传递关系,笔者采用Reynolds应力输运模型(RSM)对FCC沉降器内两级旋风分离系统进行两相数值模拟,研究了4种不同结构的流场分布特征及两级分离器间流动不稳定性的相互影响过程。结果表明,粗旋和顶旋采用合理的结构形式能更好地平衡顶旋气流,提高分离效率,降低压力降。料腿底部无约束时,粗旋排出流率较大,顶旋排出流率较小,且各顶旋排出流率并不相同。由粗旋排气管排出的气流仍有旋转特点,使方形直连管下端有漩涡区,出现了多个封闭循环流动的小漩涡,这对顶旋的流动不稳定性有重要的影响。
The two-stage separation system in a disengager is an important part of a fluidized catalytic cracking process(FCC).To analyze the characteristics of three dimensional unsteady flow distribution and the interaction of unsteady flow between primary and secondary cyclone separators,numerical simulation of four cyclone separation systems with different structures in a FCC disengager was carried out by using the Reynolds stress transport model(RSM).The results showed that appropriate distribution of two-stage cyclone was beneficial to improve the stability of flow,to increase separation efficiency and to decrease pressure drop.The flow rate of dipleg of the primary cyclone was larger than that of the secondary cyclone when the bottom of dipleg was unconstrained.Furthermore,the outflow of the primary cyclone was still highly swirly and strongly violent.This would lead to a number of small vortices forming in the bottom of the connecting pipe,which had an important effect on the flow instability in the secondary cyclone.
The two-stage separation system in a disengager is an important part of a fluidized catalytic cracking process(FCC).To analyze the characteristics of three dimensional unsteady flow distribution and the interaction of unsteady flow between primary and secondary cyclone separators,numerical simulation of four cyclone separation systems with different structures in a FCC disengager was carried out by using the Reynolds stress transport model(RSM).The results showed that appropriate distribution of two-stage cyclone was beneficial to improve the stability of flow,to increase separation efficiency and to decrease pressure drop.The flow rate of dipleg of the primary cyclone was larger than that of the secondary cyclone when the bottom of dipleg was unconstrained.Furthermore,the outflow of the primary cyclone was still highly swirly and strongly violent.This would lead to a number of small vortices forming in the bottom of the connecting pipe,which had an important effect on the flow instability in the secondary cyclone.
引文
[1]TER LINDEN A J.Investigations into cyclone dust collectors[J].Proceedings of the Institution of Mechanical Engineers,1949,160(1):233-251.
[2]YAZDABADI P A,GRIFFITHS A J.Alternate eddy shedding set up by the non-axisymmetric recirculation zone at the exhaust of a cyclone dust separator[J].Trans I Chem E,1996,74A:363-368.
[3]HOEKSTRA A J,ISRAEL A T,DERKSEN J J,et al.The application of laser diagnostics to cyclonic flow with vortex precession[C]//Proceedings of the 9th International Symposium on Applications of Laser Techniques to Fluid Mechanics,Lisbon,1998:431-435.
[4]DERKSEN J J,van den AKKER H E A.Simulation of vortex core precession in a reverse-flow cyclone[J].AIChE Journal,2000,46(7):1317-1331.
[5]STENFEN O,JAKOB W,GEMOT S.Investigation of the flow pattern in different dust outlet geometries of agas cyclone by laser Doppler anemometry[J].Powder Technology,2003,138(2-3):239-251.
[6]刘美丽,毛羽,王江云,等.催化裂化沉降器内流场数值模拟与连接结构优化[J].中国石油大学学报(自然科学版),2011,35(3):173-178.(LIU Meili,MAO Yu,WANG Jiangyun,et al.Numerical simulation of flow field and optimization of linkage structure in FCC disengage[J].Journal of China University of Petroleum(Edition of Natural Science),2011,35(3):173-178.)
[7]王娟,毛羽,钟安海,等.FCC沉降器全部空间三维流场的数值模拟[J].石油学报(石油加工),2007,23(5):15-21.(WANG Juan,MAO Yu,ZHONG Anhai,et al.Numerical simulation of 3Dturbulent flow in a FCC disengage[J].Acta Petrolei Sinica(Petroleum Processing Section),2007,23(5):15-21.)
[8]王江云,毛羽,王娟,等.FCC沉降器内粗旋与顶旋分离器连接结构的优化[J].石油学报(石油加工),2008,24(3):251-255.(WANG Jiangyun,MAO Yu,WANG Juan.et al.Optimization of linkage structure between primary and secondary separator in FCC disengagers[J].Acta Petrolei Sinica(Petroleum Processing Section),2008,24(3):251-255.)
[9]刘美丽,毛羽,王江云,等.FCC粗旋与顶旋连接方式对顶旋气量分配的影响[J].石油学报(石油加工),2010,26(5):718-724.(LIU Meili,MAO Yu,WANG Jiangyun,et al.Impact of linkage type between primary and secondary cyclone on oil-gas distribution in FCC[J].Acta Petrolei Sinica(Petroleum Processing Section),2010,26(5):718-724.)
[10]陈建义,高锐,刘秀林,等.差异旋风分离器并联性能测量及流场分析[J].化工学报,2016,67(8):3287-3295.(CHEN Jianyi,GAO Rui,LIU Xiulin,et al.Measurement of separation performance and numerical analysis on flow field of different cyclone separators in parallel[J].Journal of Chemical Industry and Engineering(China),2016,67(8):3287-3295.)
[11]陈建义,时铭显.丙烯晴反应器国产旋风分离器的性能及工业应用[J].化工机械,2003,30(6):367-371.(CHEN Jianyi,SHI Mingxian.Performance and applications of the home-made cyclone separators in acrylonitrile reactors[J].Chemical Engineering&Machinery,2003,30(6):367-371.)
[12]刘丰,陈建义,张爱琴,等.并联旋风分离器的旋流稳定性分析[J].过程工程学报,2015,15(6):923-928.(LIU Feng,CHENG Jianyi,ZHANG Aiqin,et al.Analysis on stability of vortex flow in parallel cyclones[J].The Chinese Journal of Process Engineering,2015,15(6):923-928.)
[13]魏耀东,燕辉,时铭显.蜗壳式旋风分离器环形空间流场的研究[J].石油炼制与化工,2000,31(11):46-50.(WEI Yaodong,YAN Hui,SHI Mingxian.Study on flow in the annular space of a cyclone separator with a volute inlet[J].Petroleum Processing and Petrochemical,2000,31(11):46-50.)
[14]吴小林,熊至宜,姬忠礼,等.旋风分离器旋进涡核的数值模拟[J].化工学报,2007,58(2):383-390.(WU Xiaolin,XIONG Zhiyi,JI Zhongli,et al.Numerical simulation of processing vortex core in cyclone separator[J].Journal of Chemical Industry and Engineering(China),2007,58(2):383-390.)
[15]王江云,毛羽,孟文,等.旋风分离器内非轴对称旋转流场的测量[J].石油学报(石油加工),2015,31(4):920-928.(WANG Jiangyun,MAO Yu,MENG Wen,et al.Experimental measurement of non-axisymmetric rotating flow field in cyclone separator[J].Acta Petrolei Sinica(Petroleum Processing Section),2015,31(4):920-928.)
[16]毛羽,庞磊,王小伟,等.旋风分离器内三维紊流场的数值模拟[J].石油炼制与化工,2002,33(2):1-6.(MAO Yu,PANG Lei,WANG Xiaowei,et al.Numerical modeling of three-dimension turbulent field in cyclone separator[J].Petroleum Processing and Petrochemical,2002,33(2):1-6.)
[17]刘淑艳,张雅,王保国.用RSM模拟旋风分离器内的三维湍流流场[J].北京理工大学学报,2005,25(5):377-380.(LIU Shuyan,ZHANG Ya,WANG Baoguo.Cyclone separator three-dimensional turbulent flow-field simulation using the Reynolds stress model[J].Transactions of Beijing Institute of Technology,2005,25(5):377-380.)
[18]周力行.湍流气粒两相流动和燃烧的理论与数值模拟[M].北京:科学出版社,1994:155-157.
[19]严超宇,吴小林,时铭显.旋风分离器非稳态流场的简化分析[J].流体机械,2002,30(3):18-21.(YAN Chaoyu,WU Xiaolin,SHI Mingxian.Simplified analysis of the unsteady flow field in a cyclone separator[J].Flow Machinery,2002,30(3):18-21.)
[20]高翠芝,孙国刚,董瑞倩.旋风分离器旋涡尾端测量及压力特性分析[J].化工学报,2010,61(6):1399-1405.(GAO Cuizhi,SUN Guogang,DONG Ruiqian.Analysis on location and pressure of vortex end in gas cyclone[J].Journal of Chemical Industry and Engineering(China),2010,61(6):1399-1405.)
[21]岑可法.气固分离理论及技术[M].杭州:浙江大学出版社.1999:5-10.
[22]高翠芝.旋风分离器旋转涡核流动特性及其对分离性能影响的研究[D].北京:中国石油大学,2011:27-28.
[2]YAZDABADI P A,GRIFFITHS A J.Alternate eddy shedding set up by the non-axisymmetric recirculation zone at the exhaust of a cyclone dust separator[J].Trans I Chem E,1996,74A:363-368.
[3]HOEKSTRA A J,ISRAEL A T,DERKSEN J J,et al.The application of laser diagnostics to cyclonic flow with vortex precession[C]//Proceedings of the 9th International Symposium on Applications of Laser Techniques to Fluid Mechanics,Lisbon,1998:431-435.
[4]DERKSEN J J,van den AKKER H E A.Simulation of vortex core precession in a reverse-flow cyclone[J].AIChE Journal,2000,46(7):1317-1331.
[5]STENFEN O,JAKOB W,GEMOT S.Investigation of the flow pattern in different dust outlet geometries of agas cyclone by laser Doppler anemometry[J].Powder Technology,2003,138(2-3):239-251.
[6]刘美丽,毛羽,王江云,等.催化裂化沉降器内流场数值模拟与连接结构优化[J].中国石油大学学报(自然科学版),2011,35(3):173-178.(LIU Meili,MAO Yu,WANG Jiangyun,et al.Numerical simulation of flow field and optimization of linkage structure in FCC disengage[J].Journal of China University of Petroleum(Edition of Natural Science),2011,35(3):173-178.)
[7]王娟,毛羽,钟安海,等.FCC沉降器全部空间三维流场的数值模拟[J].石油学报(石油加工),2007,23(5):15-21.(WANG Juan,MAO Yu,ZHONG Anhai,et al.Numerical simulation of 3Dturbulent flow in a FCC disengage[J].Acta Petrolei Sinica(Petroleum Processing Section),2007,23(5):15-21.)
[8]王江云,毛羽,王娟,等.FCC沉降器内粗旋与顶旋分离器连接结构的优化[J].石油学报(石油加工),2008,24(3):251-255.(WANG Jiangyun,MAO Yu,WANG Juan.et al.Optimization of linkage structure between primary and secondary separator in FCC disengagers[J].Acta Petrolei Sinica(Petroleum Processing Section),2008,24(3):251-255.)
[9]刘美丽,毛羽,王江云,等.FCC粗旋与顶旋连接方式对顶旋气量分配的影响[J].石油学报(石油加工),2010,26(5):718-724.(LIU Meili,MAO Yu,WANG Jiangyun,et al.Impact of linkage type between primary and secondary cyclone on oil-gas distribution in FCC[J].Acta Petrolei Sinica(Petroleum Processing Section),2010,26(5):718-724.)
[10]陈建义,高锐,刘秀林,等.差异旋风分离器并联性能测量及流场分析[J].化工学报,2016,67(8):3287-3295.(CHEN Jianyi,GAO Rui,LIU Xiulin,et al.Measurement of separation performance and numerical analysis on flow field of different cyclone separators in parallel[J].Journal of Chemical Industry and Engineering(China),2016,67(8):3287-3295.)
[11]陈建义,时铭显.丙烯晴反应器国产旋风分离器的性能及工业应用[J].化工机械,2003,30(6):367-371.(CHEN Jianyi,SHI Mingxian.Performance and applications of the home-made cyclone separators in acrylonitrile reactors[J].Chemical Engineering&Machinery,2003,30(6):367-371.)
[12]刘丰,陈建义,张爱琴,等.并联旋风分离器的旋流稳定性分析[J].过程工程学报,2015,15(6):923-928.(LIU Feng,CHENG Jianyi,ZHANG Aiqin,et al.Analysis on stability of vortex flow in parallel cyclones[J].The Chinese Journal of Process Engineering,2015,15(6):923-928.)
[13]魏耀东,燕辉,时铭显.蜗壳式旋风分离器环形空间流场的研究[J].石油炼制与化工,2000,31(11):46-50.(WEI Yaodong,YAN Hui,SHI Mingxian.Study on flow in the annular space of a cyclone separator with a volute inlet[J].Petroleum Processing and Petrochemical,2000,31(11):46-50.)
[14]吴小林,熊至宜,姬忠礼,等.旋风分离器旋进涡核的数值模拟[J].化工学报,2007,58(2):383-390.(WU Xiaolin,XIONG Zhiyi,JI Zhongli,et al.Numerical simulation of processing vortex core in cyclone separator[J].Journal of Chemical Industry and Engineering(China),2007,58(2):383-390.)
[15]王江云,毛羽,孟文,等.旋风分离器内非轴对称旋转流场的测量[J].石油学报(石油加工),2015,31(4):920-928.(WANG Jiangyun,MAO Yu,MENG Wen,et al.Experimental measurement of non-axisymmetric rotating flow field in cyclone separator[J].Acta Petrolei Sinica(Petroleum Processing Section),2015,31(4):920-928.)
[16]毛羽,庞磊,王小伟,等.旋风分离器内三维紊流场的数值模拟[J].石油炼制与化工,2002,33(2):1-6.(MAO Yu,PANG Lei,WANG Xiaowei,et al.Numerical modeling of three-dimension turbulent field in cyclone separator[J].Petroleum Processing and Petrochemical,2002,33(2):1-6.)
[17]刘淑艳,张雅,王保国.用RSM模拟旋风分离器内的三维湍流流场[J].北京理工大学学报,2005,25(5):377-380.(LIU Shuyan,ZHANG Ya,WANG Baoguo.Cyclone separator three-dimensional turbulent flow-field simulation using the Reynolds stress model[J].Transactions of Beijing Institute of Technology,2005,25(5):377-380.)
[18]周力行.湍流气粒两相流动和燃烧的理论与数值模拟[M].北京:科学出版社,1994:155-157.
[19]严超宇,吴小林,时铭显.旋风分离器非稳态流场的简化分析[J].流体机械,2002,30(3):18-21.(YAN Chaoyu,WU Xiaolin,SHI Mingxian.Simplified analysis of the unsteady flow field in a cyclone separator[J].Flow Machinery,2002,30(3):18-21.)
[20]高翠芝,孙国刚,董瑞倩.旋风分离器旋涡尾端测量及压力特性分析[J].化工学报,2010,61(6):1399-1405.(GAO Cuizhi,SUN Guogang,DONG Ruiqian.Analysis on location and pressure of vortex end in gas cyclone[J].Journal of Chemical Industry and Engineering(China),2010,61(6):1399-1405.)
[21]岑可法.气固分离理论及技术[M].杭州:浙江大学出版社.1999:5-10.
[22]高翠芝.旋风分离器旋转涡核流动特性及其对分离性能影响的研究[D].北京:中国石油大学,2011:27-28.