Abstract

The study focuses on corrosion challenges for naphtha hydrotreating equipment (installed upstream of a reforming unit) caused by ammonium chloride deposits and on the development of adequate chemical engineering protection measures. Using an experimental setup, we investigated the sublimation/desublimation of ammonium chloride at varying pressures and temperatures in a medium typical of naphtha and hydrogen-bearing gas streams flowing from a naphtha hydrotreater. Superstoichiometric concentrations of hydrogen chloride were found to significantly decrease the desublimation temperature (by 30–50°C) compared to a system that has a stoichiometric HCl concentration. Consequently, solid-phase ammonium chloride exists in a wider range of temperatures and pressures. Introducing surfactants (especially higher alcohols) into the system reduces adhesion and affects the crystalline structure of salt deposits—despite the solid phase being stabilized by an excess (superstoichiometric) concentration of hydrogen chloride—which makes surfactants suitable for mitigating the salt deposition challenge. Based on the data obtained, we proposed effective chemical engineering protection methods that use water-soluble corrosion inhibitors in combination with an online automated system for organochlorine control.

中文翻译：

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石脑油加氢处理条件下作为有机氯化合物氢解模型的氯化铵体系的相平衡

摘要

该研究的重点是氯化铵沉积物对石脑油加氢处理设备（安装在重整装置上游）造成的腐蚀挑战，以及制定适当的化学工程保护措施。使用实验装置，我们研究了氯化铵在不同压力和温度下在石脑油和从石脑油加氢处理装置流出的含氢气流的典型介质中的升华/凝华。与具有化学计量 HCl 浓度的系统相比，发现超化学计量浓度的氯化氢可显着降低凝华温度（降低 30-50°C）。因此，固相氯化铵存在于更广泛的温度和压力范围内。将表面活性剂（尤其是高级醇）引入系统会降低粘附性并影响盐沉积物的晶体结构——尽管固相被过量（超化学计量）浓度的氯化氢稳定——这使得表面活性剂适合于缓解盐沉积挑战。根据获得的数据，我们提出了有效的化学工程保护方法，将水溶性缓蚀剂与有机氯控制在线自动化系统结合使用。