Abstract:

In 2020 and 2021, a styrene unit of a certain refining and chemical company encountered problems with polymer content of product storage tanks exceeding the standard and substandard products, which had a significant impact on the normal production of the unit and the delivery of products. After tank cleaning inspection, no obvious factors that could easily lead to polymerization reactions were found in tank bottom, tank wall and external safety accessories. After multiple discussions, analysis, and investigation, it was found that excessive polymer content in styrene products is related to the storage temperature, storage capacity, and residence time of styrene products in the storage tank, which is the result of the combined effect of these factors. According to the preliminary analysis results, the corresponding process parameters were adjusted during production in the summer of 2022: reducing the storage capacity of product storage tanks during high-temperature periods, reducing the residence time of products in storage tanks, and conducting preventive tank cleaning treatment on the storage tanks. The problem did not occur again throughout the summer.

Key words: styrene, product storage tank, excessive polymer content, storage temperature, polymer inhibitor, storage time, preventive tank cleaning, circulating water temperature

摘要：

某炼化公司苯乙烯装置在2020年和2021年出现产品储罐聚合物含量超标、产品不合格的问题，对装置的正常生产和产品的出厂影响很大。经清罐检查，储罐罐底、罐壁及外部安全附件等均未发现明显的易导致聚合反应发生的因素。经多次讨论、分析及排查发现：苯乙烯产品聚合物含量超标问题与储罐储存温度、储罐储量、苯乙烯产品在储罐中停留时间都有关系，是这几种因素综合作用的结果。根据前期分析结果，2022年夏季生产时对相应的工艺参数进行了调整：降低高温时期产品储罐储量、减少产品在储罐中停留时间等，并对储罐进行预防性清罐处理，整个夏季未出现储罐产品聚合物含量超标问题。

关键词: 苯乙烯, 产品储罐, 聚合物含量超标, 储存温度, 阻聚剂, 储存时间, 预防性清罐, 循环水温度