加氢裂化空冷器管束多相流冲刷腐蚀数值模拟
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摘要
基于某加氢裂化空冷器管束的冲刷腐蚀实际状况分析,建立了数值模拟模型。采用mixture模型和标准k-ε模型描述多相湍流流动过程,以此对空冷器的管箱、管束进行全流场数值模拟,获得湍动能分布状况;进而对空冷器腐蚀状况进行研究,获得不同位置处的冲刷腐蚀和电化学腐蚀速率。结果表明,最大冲刷腐蚀速率达到4.76 mm/a,且腐蚀损伤集中在空冷器管束进口端,模拟结果与空冷器管束实际腐蚀状况一致。模拟结果表明,与电化学腐蚀相比,冲刷腐蚀是导致空冷器管束腐蚀损坏的主要原因。在此基础上,提出对空冷器结构进行改进的技术方案;模拟计算表明,结构改进后的空冷器管束的冲刷腐蚀速率大大降低,显著提高了空冷器运行的安全与稳定性。
Air cooler is the key equipment in the process of hydrocracking. The corrosion of air cooler becomes a prominent problem in the safe and stable operation of equipment. In this paper, a numerical simulation model is established based on the analysis of the erosion corrosion of the air cooler tubes in a hydrocracking unit. The mixture model and the standard k-ε model of CFD simulation software is used to simulate the whole flow field of the tube box and tube bundle of the air cooler. The corrosion position of the air cooler is predicted by the turbulent kinetic energy distribution. The corrosion amount of erosion corrosion and electrochemical corrosion are predicted as well. According to the simulation, the maximum erosion amount is 4.76 mm/a, and it is concentrated at the inlet of the tube bundle of air cooler. The simulation results are consistent with the actual corrosion of the air cooler. Comparing with electrochemical corrosion, erosion corrosion is the main cause of corrosion of air cooler. The amount of erosion and corrosion of the tube bundle of air cooler has been greatly reduced after the retrofit of the air cooler structure, therewith, the safety and stability of the air cooler have been greatly improved.
Air cooler is the key equipment in the process of hydrocracking. The corrosion of air cooler becomes a prominent problem in the safe and stable operation of equipment. In this paper, a numerical simulation model is established based on the analysis of the erosion corrosion of the air cooler tubes in a hydrocracking unit. The mixture model and the standard k-ε model of CFD simulation software is used to simulate the whole flow field of the tube box and tube bundle of the air cooler. The corrosion position of the air cooler is predicted by the turbulent kinetic energy distribution. The corrosion amount of erosion corrosion and electrochemical corrosion are predicted as well. According to the simulation, the maximum erosion amount is 4.76 mm/a, and it is concentrated at the inlet of the tube bundle of air cooler. The simulation results are consistent with the actual corrosion of the air cooler. Comparing with electrochemical corrosion, erosion corrosion is the main cause of corrosion of air cooler. The amount of erosion and corrosion of the tube bundle of air cooler has been greatly reduced after the retrofit of the air cooler structure, therewith, the safety and stability of the air cooler have been greatly improved.
引文
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[15]Ou G F,Cao J,Xie H P.Coupled simulation of flow and heat transfer for hydrocracker’s air coolers tubes[J].Petr.Refin.Eng.,2010,40(11):42(偶国富,曹晶,谢浩平.加氢裂化空冷管束流动传热的耦合模拟[J].炼油技术与工程,2010,40(11):42)
[16]Sun L,Zhu M,Ou G F,et al.Corrosion investigation of the inlet section of REAC pipes in the refinery[J].Eng.Fail.Anal.,2016,66:468
[17]Valeh-E-Sheyda P,Rashidi H.Inhibition of corrosion in amine air cooled heat exchanger:Experimental and numerical study[J].Appl.Therm.Eng.,2016,98:1241
[18]Hu Y H.Evaluation of erosion-corrosion of typical pipe fittings via CFD[D].Hangzhou:Zhejiang University,2012(胡跃华.典型管件冲刷腐蚀的数值模拟[D].杭州:浙江大学,2012)
[19]Stack M M,Corlett N,Turgoose S.Some recent advances in the development of theoretical approaches for the construction of erosion-corrosion maps in aqueous conditions[J].Wear,1999,233-235:535
[20]Stack M M,Corlett N,Zhou S.Impact angle effects on the transition boundaries of the aqueous erosion-corrosion map[J].Wear,1999,225-229:190
[21]Huser A,Kvernvold O.Prediction of sand erosion in process and pipe components[A].Proceedings of the 1st North American Conference on Multiphase Technology[C].Banff,Canada,1998:217
[22]McLaury B S,Shirazi S A.An Alternate method to API RP 14Efor predicting solids erosion in multiphase flow[J].J.Energy Resour.Technol.,2000,122:115
[23]Zheng Y G,Yao Z M,Ke W.Review on the effects of hydrodynamic factors on erosion-corrosion[J].Corros.Sci.Prot.Technol.,2000,12:36(郑玉贵,姚治铭,柯伟.流体力学因素对冲刷腐蚀的影响机制[J].腐蚀科学与防护技术,2000,12:36)
[24]Schiller L,Naumann A.A drag coefficient correlation[J].Z.Ver.Deutsch.Ing.,1935,77:318
[2]Ellison B T,Wen C J.Hydrodynamic effects on corrosion[J].AlChESymp.Ser.,1981,77:161
[3]Syrett B C.Erosion-corrosion of copper-nickel alloys in sea water and other aqueous environments-A literature review[J].Corrosion,1976,32:242
[4]Clark H M.The influence of the flow field in slurry erosion[J].Wear,1992,152:223
[5]Stack M M,Chacon-Nava J,Stott F H.Relationship between the effects of velocity and alloy corrosion resistance in erosion-corrosion environments at elevated temperatures[J].Wear,1995,180:91
[6]Liu J J,Yong X Y,Lin Y Z,et al.Erosion-corrosion behavior of carbon steel in different simulated flowing apparatuses[J].Mater.Prot.,2003,36(9):25(刘景军,雍兴跃,林玉珍等.不同流动体系中碳钢磨损腐蚀可比性的研究[J].材料保护,2003,36(9):25)
[7]Ren C Q,Liu D X,Bai Z Q,et al.Study on mechanical properties of corrosion scale on surface of tubular steel N80[J].J.Mater.Eng.,2004,(8):17(任呈强,刘道新,白真权等.N80油管钢腐蚀产物膜的力学性能研究[J].材料工程,2004,(8):17)
[8]Zeng M Q.Study on the causes of overhead air coolers failure of atmospheric distillation column[J].Corros.Prot.Petrochem.Ind.,2003,20(1):30(曾孟秋.常顶空冷器失效原因探讨[J].石油化工腐蚀与防护,2003,20(1):30)
[9]Liu X K,Fang Q X.Erosion corrosion of 2Cr13 and 1Cr17Mo2[J].Chem.Eng.Mach.,1998,25(1):12(刘新宽,方其先.两种不锈钢冲刷腐蚀的研究[J].化工机械,1998,25(1):12)
[10]Zheng Y G,Yao Z M,Long K,et al.Development of liquid/solid two-phase flow scour corrosion test apparatus and dynamic electrochemical test[J].Corros.Sci.Prot.Technol.,1993,5:286(郑玉贵,姚治铭,龙康等.液/固双相流冲刷腐蚀实验装置的研制及动态电化学测试[J].腐蚀科学与防护技术,1993,5:286)
[11]Bhongale S.Effect of pressure,temperature and Froude number on corrosion rates in horizontal multiphase slug flow[D].Athens:Ohio University,1996
[12]Zheng D H,Che D F.Experimental study on hydrodynamic characteristics of upward gas-liquid slug flow[J].Int.J.Multiph.Flow,2006,32:1191
[13]Chen L H,Fan J R,Cen K F.Numerical study on the flow features of U-beam inertial separator[J].J.Zhejiang Univ.Sci.,2002,3:387
[14]Ou G F,Zhan J L,Tang M,et al.Numerical simulation and erosion prediction of complete flow field of hydrogenation high pressure air cooler[J].Petr.Refin.Eng.,2011,41(10):34(偶国富,詹剑良,唐萌等.加氢高压空冷器全流场数值模拟和冲蚀预测[J].炼油技术与工程,2011,41(10):34)
[15]Ou G F,Cao J,Xie H P.Coupled simulation of flow and heat transfer for hydrocracker’s air coolers tubes[J].Petr.Refin.Eng.,2010,40(11):42(偶国富,曹晶,谢浩平.加氢裂化空冷管束流动传热的耦合模拟[J].炼油技术与工程,2010,40(11):42)
[16]Sun L,Zhu M,Ou G F,et al.Corrosion investigation of the inlet section of REAC pipes in the refinery[J].Eng.Fail.Anal.,2016,66:468
[17]Valeh-E-Sheyda P,Rashidi H.Inhibition of corrosion in amine air cooled heat exchanger:Experimental and numerical study[J].Appl.Therm.Eng.,2016,98:1241
[18]Hu Y H.Evaluation of erosion-corrosion of typical pipe fittings via CFD[D].Hangzhou:Zhejiang University,2012(胡跃华.典型管件冲刷腐蚀的数值模拟[D].杭州:浙江大学,2012)
[19]Stack M M,Corlett N,Turgoose S.Some recent advances in the development of theoretical approaches for the construction of erosion-corrosion maps in aqueous conditions[J].Wear,1999,233-235:535
[20]Stack M M,Corlett N,Zhou S.Impact angle effects on the transition boundaries of the aqueous erosion-corrosion map[J].Wear,1999,225-229:190
[21]Huser A,Kvernvold O.Prediction of sand erosion in process and pipe components[A].Proceedings of the 1st North American Conference on Multiphase Technology[C].Banff,Canada,1998:217
[22]McLaury B S,Shirazi S A.An Alternate method to API RP 14Efor predicting solids erosion in multiphase flow[J].J.Energy Resour.Technol.,2000,122:115
[23]Zheng Y G,Yao Z M,Ke W.Review on the effects of hydrodynamic factors on erosion-corrosion[J].Corros.Sci.Prot.Technol.,2000,12:36(郑玉贵,姚治铭,柯伟.流体力学因素对冲刷腐蚀的影响机制[J].腐蚀科学与防护技术,2000,12:36)
[24]Schiller L,Naumann A.A drag coefficient correlation[J].Z.Ver.Deutsch.Ing.,1935,77:318