柴油加氢装置循环氢纯度下降原因分析及对策

中国石油化工股份有限公司镇海炼化分公司3.0 Mt/a柴油加氢装置自开工以来循环氢纯度逐渐下降.通过对循环氢和补入氢(以下简称新氢)组成的对比发现,新氢中氩气含量较高,该组分随着运行时间增长存在累积过程,导致循环氢纯度逐渐下降.搭建模型分析研究热高分入口温度、冷高分入口温度对氩气溶解度及循环氢纯度的影响,确定了冷高分入口温度是影响循环氢纯度的主要工艺参数.综合上述分析,通过切换新氢来源(氩气体积分数小于0.3%)、降低冷高分入口温度两方面措施,提高了循环氢纯度,保证了加氢反应深度,解决了新氢中氩气造成柴油加氢装置循环氢纯度下降的问题.

Cause analysis and countermeasure for decreasing purity of recycle hydrogen in diesel hydrogenation unit

The purity of recycle hydrogen in 3.0 MM TPY diesel hydrogenation unit of SINOPEC Zhenhai Refining&Chemical Co.,Ltd.has gradually decreased since its start-up.By comparing the composition of recycle hydrogen with that of supplemented hydrogen(new hydrogen),it is found that the argon content in new hydrogen is relatively high,and the component accumulates in the recycle hydrogen system of diesel hydrogenation unit with the running time,resulting in the gradual decrease of the purity of recycle hydrogen.The effects of inlet temperature of hot high pressure separator and cold high pressure separator on the solubility of argon and purity of recycle hydrogen are studied by model analysis.The inlet temperature of cold high pressure separator is determined to be the main process parameter affecting purity of recycle hydrogen.Based on the above analysis,by switching the new hydrogen source(the volume fraction of argon is less than 0.3%)and reducing the inlet temperature of the cold high pressure separator,the purity of recycle hydrogen is improved,the reaction depth is ensured,and the problem of decreasing the purity of recycle hydrogen in diesel hydrogenation unit caused by argon in new hydrogen is solved.