烟道气CO_2回收系统的腐蚀原因分析及对策

Cause analysis and countermeasures for corrosion of flue gas CO_2 recovery system

介绍了某20万t/a甲醇装置烟气CO_2回收系统易发生腐蚀的部位及腐蚀情况,从腐蚀机理、工艺控制、溶剂条件、设备改造等方面对系统的腐蚀原因进行分析探讨,找出造成吸收塔、富液管线等碳钢设备腐蚀的原因,并提出相应的解决措施。通过更换脱碳溶液配方、对关键设备材料进行升级、降低富液中的CO_2含量、对腐蚀严重的部位进行监测,解决了由于装置腐蚀造成的产能下降问题,CO_2产量恢复,甲醇的生产成本下降,装置运行稳定,效益显著提高。

The location and situation of corrosion of flue gas CO2 recovery device in a 200 kt/a methanol unit is described. The corrosion causes are analyzed and discussed from aspects of corrosion meehanism, process control, solvent conditions, equipment modification, etc. , the causes which result in corrosion of carbon steel equipment, such as absorption tower and rich solution pipelines, are determined, and the corresponding measures are put forward and put into practice. By means of changing the fornmla of decarbonation solution, upgrading the materials of key equipment, reducing the content of carbon dioxide in rich solution and monitoring the location of seriously corroded, the problem of deeline of capacity due to corrosion is solved. As a result, carbon dioxide production is recovered, methanol producing cost is reduced, the device operates stably and the benefit is remarkably increased.