Abstract:

Diesel hydrogenation process is an important means to produce refined diesel with catalytic diesel as feedstock. Hydrogenated air cooler is one of the key equipments of diesel hydrogenation unit. Due to the strong corrosion of catalytic diesel oil and the harsh operating conditions of the equipment, the corrosion failure of air cooler tube bundles occurs frequently, which seriously affects the long-term safe and reliable operation of the unit. This paper takes a diesel hydrogenation air cooler in a petrochemical enterprise as the research object, analyzes its process correlation process and determines the source of corrosion hazards. The PR-NRTL model of state is used to establish a multi-component fluid phase state-ion balance model for the hydrogenation reaction effluent system, and the risk assessment of ammonium salt crystallization under typical working conditions is carried out. By analyzing the risk of ammonium salt crystallization in air cooler tube bundles under variable working conditions, the correlation between N and Cl contents and ammonium salt crystallization temperature is studied. Finally, the corresponding process protection measures are proposed for the possible corrosion risks of air cooler.

Key words: hydrogenation air cooler, ammonium chloride crystallization, risk assessment, corrosion prevention and control, expert supervision

摘要：

柴油加氢工艺是以催化裂化柴油(催化柴油)为原料生产精制柴油的重要手段，加氢空气冷却器(空冷器)为柴油加氢装置关键设备之一。因催化柴油腐蚀性强、设备运行工况苛刻，空冷器管束腐蚀失效问题频发，严重影响装置长周期安全可靠运行。文中以某炼化企业柴油加氢空冷器为研究对象，分析其工艺关联过程，确定腐蚀危害源；采用PR-NRTL状态方程，对加氢反应流出物系统建立多组分流体相态-离子平衡模型，进行典型工况下铵盐结晶风险评估；分析变工况条件下空冷器管束铵盐结晶风险，研究N,Cl含量与铵盐结晶温度之间的关联关系；针对空冷器可能存在的腐蚀风险提出了相应工艺防护措施。

关键词: 加氢空冷器, 氯化铵结晶, 风险评估, 腐蚀防控, 专家监管