空分装置预冷系统低温垢形成原因及在线清洗

Causes of Low Temperature Scale Formation in Precooling System of Air Separation Unit and On-line Cleaning

简述了空分装置的主要用途、设备和工艺流程图,介绍了预冷系统的关键装置水冷塔和空冷塔的原理及工艺流程。水冷塔中的水质"二次浓缩"、低温降低了无机盐分子运动活性以及局部pH值的升高是空分预冷系统低温垢产生的主要原因。冷垢会造成空分装置能耗增加、堵塞冷却水管道、降低冷却水流量,影响空分产气量,甚至会造成停车等危害。通过实际现场应用,总结了在线酸性清洗低温垢的操作步骤以及注意事项,为在线解决低温垢的难题提供了参考案例,避免了空分装置非计划停车,节约了能耗及运行费用。

The main equipment、applications and process flow chart of air separation unit are briefly described.The principle and process of water-cooling tower and air-cooling tower,which are key devices of conventional precooling system,are introduced.The secondary concentration of water quality,the decrease of movement activity of inorganic salt molecules at low temperature and the increase of local pH are the main reasons for the formation of low temperature scale in air separation precooling system.The cold scale will increase the energy consumption of air separation unit,block the cooling water pipe,reduce the flow of cooling water,affect the air separation production and even cause the shutdown of the unit.Based on the practical filed application,the operation steps and points for attention in on-line acid cleaning of low temperature scale are summarized.It provides a reference case for solution of cold scale problem,and this can avoid unplanned shutdown of air separation unit,and this saves energy consumption and operation cost.