干气提纯氢装置局部腐蚀分析及防护措施

Analysis of local corrosion of dry gas hydrogen extraction unit and protective measures

中国石油某石化公司炼油厂干气提纯氢气装置运行一年半后停车检修,出现了包括压缩机本体在内的局部设备及管道腐蚀。结合操作介质中的腐蚀成分(CO_2,H_2S)以及腐蚀产物进行分析,认为游离水是产生腐蚀的必要条件,腐蚀为CO_2腐蚀为主、H_2S腐蚀为辅的复合型腐蚀。对压缩机本体部分配件及管道进行了材质升级并优化布置,提出了防腐措施:改变压缩机级间冷却器型式并优化布置;重整富氢原料气增设精细过滤器;压缩机操作调整及压缩机部分零部件材质升级,局部管道材质升级等。确保装置可长周期稳定运行。

The corrosions were found on equipment and pipings including compressor in the shutdown for maintenance after 1. 5 years＇ operation of a dry gas hydrogen purification unit in a refinery of CPECC. By the analysis of corrosive components of CO_2,H_2S as well as the corrosion products,it is concluded that the free water is the necessary condition for the occurrence of corrosion. The corrosion is mainly CO_2 corrosion combined with H_2S corrosion. The materials for the compressor fittings and pipings are upgraded and layout is optimized. The following corrosion prevention measures are recommended： the inter-stage cooling should be changed and layout should be optimized; a fine filter should be installed for CCR rich hydrogen gas; the operation of compressor should be adjusted and fine filter should be added; the operation of compressor should be adjusted and the materials of some compressor fittings and pipings should be upgraded.