冷箱系统高压甲烷堵塞原因分析及处理方法

CAUSE ANALYSIS AND TREATMENT METHODS FOR FREEZE BLOCKAGE IN HIGH PRESSURE METHANE PIPELINE OF COLD BOX SYSTEM

介绍了天津乙烯冷箱系统高压甲烷线冻堵情况,分析了高压甲烷管线冻堵原因,简要介绍并比较了不同处理方法的优缺点,提出了相关建议。分析认为,利用甲醇清洗冷箱有效解决了冷箱甲烷出口压力降低、脱甲烷塔塔顶温度高、塔顶乙烯损失大等问题。但甲烷制冷压缩机活塞环磨损、压缩甲烷混合物中乙烯含量较高,仍是制约冷箱长周期运行的瓶颈,需要对压缩机进行定期维护,并在操作过程中严格控制脱甲烷塔顶温,避免不饱和烃类带入。

This paper introduces the freeze blorkage in the high pressure methane pipeline of cold box system in the ethylene plant in Tianjin.analyzes the reasons for the freeze blockager.brigfly introduces and compares the advantages and disadvantages of various treatment methods,and presents some corresponding suggestions.The analysis results show that washing the cold box with methanol can effectively solve the problems including the decreased pressure of methune at the oultet of cold box,the high temperature at the top of dentethanizer and the high loss of overhead ethylene,but the wear of piston ring in methane refrigeration compressor and the high ethylene content of compressed methane mixture are still the bottlenecks that restrict the long-term operation of cold box.Regular maintenance of the compressor is neressary and the overhead temperature of demethanizer is to be strirtly controlled during operation,so as to avoid the entrainment of unsalurated hydrocarbons.