加氢反应产物空冷系统设备材料的选择

Material selection for equipment of hydrogenation reaction effluent air cooling system

加氢空冷系统的腐蚀主要为结晶铵盐垢下腐蚀及铵盐水溶液冲刷腐蚀。介绍了国际上对结晶NH4Cl垢下腐蚀、NH4Cl水溶液浸泡腐蚀及铵盐水溶液冲刷腐蚀的研究,阐述了反应产物空冷系统空冷器、换热器选材的要点。研究表明气相H2S分压对冲刷腐蚀有较大影响,2507超级双相不锈钢、254SMo超级不锈钢有较好的耐垢下腐蚀和冲刷腐蚀性能;空冷器采用碳钢时,还应考虑H2S分压的影响;为使空冷器中各相均匀分布,应控制空冷器单程管排数和单片宽度;换热器的腐蚀和选材与结晶有关且涉及到装置Cl元素含量。最后提出对空冷系统设备选材的几点建议。

The main corrosions in hydrogenation reaction effluent air cooling system are mainly the under- deposit corrosion of ammonium salt and the erosion of moving ammonium salt solution. The study on the NH4Cl under-deposit corrosion, the corrosion of NH4Cl solution and the erosion of moving ammonium salt so- lution in the world is introduced, and the major issues in material selection and construction design of the hy- drogenation effluent air cooler and heat exchanger are discussed. The study indicates that the partial pressure of gas-phase H2S has a greater impact on the erosion corrosion, and the 2507 super duplex stainless steel, 254SMo super stainless steel have good resistance to under-deposit corrosion and erosion corrosion. For carbon steel air cooler, the impact of H2S partial pressure on erosion corrosion should also be considered. In order to have a uniform phase distribution in air cooler, the row number of pass tubes and chip width of air cooler should be controlled. The corrosion and material selection of the heat exchanger are related to the crystalliza- tion and the content of Cl element in the unit. Finally, some suggestions are put forward for the material selec- tion and structure design of air cooling system equipment. Recommendations for the material selection for the equipment in air cooling system are finally presented.