Chemical Industry and Engineering Progress ›› 2023, Vol. 42 ›› Issue (6): 2809-2818.DOI: 10.16085/j.issn.1000-6613.2022-1529

• Chemical processes and equipment • Previous Articles     Next Articles

Hygroscopic properties and corrosion behavior of ammonium salt in a crude oil distillation column

LI Ruidong1(), HUANG Hui2, TONG Guohu1, WANG Yueshe1()   

  1. 1.State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, Shaanxi, China
    2.China Special Equipment Inspection & Research Institute, Beijing 100029, China
  • Received:2022-08-18 Revised:2022-09-29 Online:2023-06-29 Published:2023-06-25
  • Contact: WANG Yueshe

原油精馏塔中铵盐吸湿特性及其腐蚀行为

李瑞东1(), 黄辉2, 同国虎1, 王跃社1()   

  1. 1.西安交通大学动力工程多相流国家重点实验室,陕西 西安 710049
    2.中国特种设备检测研究院,北京 100029
  • 通讯作者: 王跃社
  • 作者简介:李瑞东(1995—),男,博士研究生,研究方向为化工过程腐蚀。E-mail:liruidong@stu.xjtu.edu.cn

Abstract:

The corrosion problem caused by ammonium salts deposition in the top circulation system of crude oil distillation column is one of the problems that lead to local failure and leakage of equipment and pipelines. To understand the mechanism of corrosion, the simulation method of Ab initio molecular dynamics (AIMD) and the experimental method of in situ electrochemical measurements were conducted to explore the hygroscopic properties of ammonium salts and the corrosion evolution for SAE 1020 carbon steel at different temperatures and concentrations. The results of electrochemical impedance spectroscopy and surface characterization reflected that the interfacial process of corrosion was a dynamic mass transfer process under the influence of corrosion product growth, film formation and damage behavior, combined with linear polarization resistance and weight loss tests, and the change of corrosion rate was determined by the mass transfer effect of the product and the electrode reaction process. The results of AIMD demonstrated that the charge state in the system under the action of water molecules was altered, including ionization, hydrolysis, proton transfer chain, etc., which may be an important cause of corrosion.

Key words: corrosion, reaction dynamics, molecular simulation, interface, mass transfer

摘要:

原油精馏塔顶部循环系统中由于铵盐沉积引发的腐蚀问题,是导致设备及管道局部失效泄漏的问题之一。为了认识铵盐腐蚀的机理,本文采用了从头算分子动力学(AIMD)的模拟方法以及原位电化学测试的实验方法分别探究了铵盐的吸湿潮解特性及其溶液在不同温度与浓度下对于20号碳钢的腐蚀演化规律。电化学阻抗谱与表面表征结果反映了腐蚀的界面过程是受腐蚀产物生长、成膜以及破损行为影响下的动态传质过程,结合线性极化电阻以及失重测试揭示了腐蚀速率的变化是由产物的传质效应与电极反应过程共同决定。AIMD模拟结果表明NH4Cl在水分子的作用下会发生包括电离、水解、质子转移链等一系列反应使得溶液呈酸性,并导致体系中的电荷状态发生了改变,这可能是引发腐蚀的一个重要原因。

关键词: 腐蚀, 反应动力学, 分子模拟, 界面, 传质

CLC Number: 

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