常压蒸馏塔塔顶回流管线露点腐蚀形成机制及影响因素研究

石油炼制与化工 ›› 2023, Vol. 54 ›› Issue (4): 125-132.

常压蒸馏塔塔顶回流管线露点腐蚀形成机制及影响因素研究

偶国富¹,陶情情¹,金浩哲²

1. 常州大学流动腐蚀与智能防控研究所
2. 浙江理工大学流动腐蚀研究所

收稿日期:2022-07-01 修回日期:2022-12-02 出版日期:2023-04-12 发布日期:2023-04-27
通讯作者: 金浩哲 E-mail:haozhejin@zstu.edu.cn
基金资助:
国家自然科学基金;国家自然科学基金

RESEARCH ON FORMATION MECHANISM AND INFLUENCING FACTORS OF DEW POINT CORROSION IN ATMOSPHERIC DISTILLATION COLUMN OVERHEAD LINE

1. Institute of Flow-Induced Corrosion and Intelligent Prevention and Control, Changzhou University
2. Zhejiang Flow induced Corrosion Institute

Received:2022-07-01 Revised:2022-12-02 Online:2023-04-12 Published:2023-04-27
Contact: Jin Haozhe E-mail:haozhejin@zstu.edu.cn

摘要/Abstract

摘要： 针对某石化企业常压蒸馏塔塔顶（简称常顶）回流管线出现的露点腐蚀问题，采用基于烃水二元交互的PR (Peng-Robinson)状态方程法，建立标定工况下常顶回流系统工艺计算模型。结合露点形成机制，分析露点出现前后腐蚀性介质在油气水三相中的分布变化；研究不同注水比例下塔顶回流管线中HCl和H₂S的分布情况以及原料油中不同S、N含量及常顶油量下塔顶压力、汽提蒸汽量及注水比例对露点温度的影响。结果表明：HCl和H₂S是引起露点腐蚀的关键影响因素，随着冷凝过程的进行，塔顶回流管线中的HCl含量不断增加，H2S含量呈现先增加后降低的趋势；标定工况下塔顶水的露点温度为100.45 ℃，塔顶压力、汽提蒸汽量及注水比例与露点温度均呈正相关性，其中塔顶压力对露点温度的影响最大，平均每增加0.02 MPa相应露点温度升高2.97 ℃。

关键词: 常压蒸馏塔, 塔顶回流管线, 露点温度, 塔顶压力, 汽提蒸汽量, 注水比例

Abstract: In order to solve the dew point corrosion problem in the atmospheric distillation column overhead line in a petrochemical enterprise, the PR (Peng-Robinson) state equation method based on the binary interaction of hydrocarbon and water was adopted, and the process calculation model of the overhead system under standard conditions was established. Based on the mechanism of the dew point formation, the state changes of the corrosive medium in the oil-gas-water three-phase before and after the dew point were analyzed. The distribution of HCl and H₂S in the overhead line of the column under different water injection ratios and the influence of top pressure, stripping steam volume and water injection ratio on dew point temperature under different S and N contents in the feed oil and constant oil content were studied. The results showed that HCl and H₂S were the key factors causing dew point corrosion. With the condensation process, the content of HCl in the overhead line of the column increasesd, and the content of H2S increased first and then decreased. The dew point temperature of the overhead water is 100.45 °C, and there is a positive correlation between the column top pressure, stripping steam quantity, the water injection ratio and the dew point temperature, the average dew point temperature increases by 2.97 °C per 0.02 MPa of top pressure increases.

Key words: atmospheric distillation column, overhead reflux line, dew point temperature, overhead pressure, stripping steam volume, water injection ratio

偶国富陶情情金浩哲. 常压蒸馏塔塔顶回流管线露点腐蚀形成机制及影响因素研究[J]. 石油炼制与化工, 2023, 54(4): 125-132.

参考文献

[1]Niu L N, Liu X H.Study on the cause,harm and protection of chlorides in crude oil[J].Safety Health & Environment, 2015, 15(5):1-5
[2]Stratiev D, Shishkova I, Nedelchev A, et al.Investigation of Relationships between Petroleum Properties and Their Impact on Crude Oil Compatibility[J].Energy and Fuels, 2015, 29(12):7836-7854
[3]Ou G F, Gu Y J, Yu C Y, et al.Failure analysis of ammonium chloride salt coagulation corrosion of U-tube heat exchanger in diesel hydrogenation unit[J].Engineering Failure Analysis, 2022, 137(3):106264-106285
[4]Lahiri A K.Material Selection and Performance in Refining Industry[M]. Singapore: Springer, 2017: 349-418.
[5]Antal B.Dew point corrosion in large hot water boilers[J].Korrozios Figyelo, 2011, 51(2):46-48
[6]Groysman A.Corrosion problems and solutions in oil,gas,refining and petrochemical industry[J].Nephron Clinical Practice, 2017, 61(3):100-117
[7]Mendoza-Canales J, Marin-Cruz, J.EIS characterization of corrosion processes of titanium and alloy UNSN10276 in sour environments[J].Journal of Solid State Electrochemistry, 2008, 12(12):1637-1644
[8]Papavinasam S.The Main Environmental Factors Influencing Corrosion[M]. Elsevier Inc: Gulf Professional Publishing, 2014: 179-247.
[9]Kivisakk U.A test method for dewpoint corrosion of stainless steels in dilute hydrochloric acid[J].Corrosion Science, 2003, 45(3):485-495
[10]Niu L N, Han L, Chen W W, et al.Analysis and Prediction of Corrosion Risk in Atmospheric Distillation Tower Overhead System[J].China Petroleum Processing & Petrochemical Technology, 2021, 23(1):21-30
[11]Subramanian C.Corrosion prevention of crude and vacuum distillation column overheads in a petroleum refinery: A field monitoring study[J].Process Safety Progress, 2021, 40(2):1-10
[12]Wang Y G, Zhao Q X, Zhang Z X, et al.Mechanism research on coupling effect between dew point corrosion and ash deposition[J].Applied Thermal Engineering, 2013, 54(1):102-110
[13]Liu X F, Yao H C, Wang C Y, et al.Failure analysis and prediction based on corrosion thinning behaviour of atmospheric tower top and volatilization line connection area[J].Engineering Failure Analysis, 2022, 131(2):105914-105925
[14]Xiang Y Z, Zhang L, Wang Y J, et al.Corrosion reasons of overhead circulation system of atmospheric tower for processing crude oil with high acid value[J].Corrosion & Protection, 2015, 36(12):1190-1193
[15]Peng D Y, Robinson D B.Two and three phase equilibrium calculations for systems containing water[J].The Canadian Journal of Chemical Engineering, 1976, 54(6):595-599