真空脱水技术在柴油加氢装置工业应用总结

Summary of industrial application of vacuum dehydration technology in diesel hydrogenation unit

某石化公司2.6 Mt/a柴油加氢装置产品分馏系统采用单塔汽提+电脱水生产工艺。该工艺虽新增了聚结器脱水,但生产的精制柴油水质量分数仍在90~150μg/g。水含量偏高会经常使产品外观出现浑浊现象,使产品无法满足要求。在现有脱水工艺基础上,通过新增真空脱水系统来改进装置脱水能力。投用真空脱水系统后,优化操作参数,当一级闪蒸脱水塔T105操作压力为30 kPa、塔顶流量为28 t/h,二级闪蒸脱水塔T106操作压力为-25 kPa、塔顶流量为27.7 t/h时,精制柴油脱水率高达100%,水质量分数可降至40~80μg/g,彻底改善产品外观;同时停用电脱水和聚结器脱水系统,可节约装置能耗1.92 MJ/t。

The product fractionation system of a 2.6 MM TPY diesel hydrogenation unit in a petrochemical company adopts production process of single tower stripping and electric dehydration. Although this process newly adds a coalescer dehydration, the water content of refined diesel is still at 90~150 μg/g. If the water content is too high, the appearance of the product will often appear turbid, making the product unable to meet the requirements. Based on the existing dehydration process, the dehydration capacity of the unit is improved by adding a new vacuum dehydration system. After the vacuum dehydration system is put into use, by optimizing the operating parameters, when the operating pressure of the primary flash dehydration tower(T105)is 30 kPa and its tower top flow rate is 28 t/h, and the operating pressure of the secondary flash dehydration tower(T106)is-25 kPa and its tower top flow rate is 27.7 t/h, the dehydration rate of the refined diesel is as high as 100%, the water content can be reduced to 40~80 μg/g, and the product appearance can also be thoroughly improved. At the same time, the electric dehydration and coalescer dehydration systems are stopped, saving 1.92 MJ/t of energy consumption for the unit.