苯乙烯装置尾气增压系统腐蚀分析

在苯乙烯装置吸收塔顶的尾气中,氢气体积分数超过90%,为了更好地回收利用氢气,在尾气出装置前设置尾气增压系统进行4级压缩,每级压缩后采用水冷器降温。在大修期间检查发现,水冷器气体侧的壳体内壁局部发生严重坑蚀。分析认为,该系统的腐蚀是由二氧化碳引起的。建议对该系统进行材质升级或在水冷器的壳体液相发生腐蚀的区域衬一层厚度1 mm左右的304不锈钢板,可以有效抑制该系统的腐蚀。

Corrosion Analysis of Tail Gas Pressurization System in Styrene Unit

The volume fraction of hydrogen was more than 90%in the tail gas from the top of the absorption column in a styrene unit.In order to recycle and utilize the hydrogen,tail gas pressurization system for 4-stage compression was set up before the tail gas was discharged from the unit;meanwhile,water cooler was used to cool down after each stage of compression.During the shutdown period for maintenance,it was found that the inner wall of the shell on the gas side was seriously pitted and almost perforated.The analysis showed the corrosion was caused by carbon dioxide.It was suggested material of the system should be upgraded or the area where the liquid phase of the shell corroded should be lined with a layer of 304 stainless steel with a thickness of about 1 mm,which could effectively inhibit the occurrence of corrosion.