关键词: 真空脱水, 柴油加氢装置, 液环真空泵, 真空脱水塔, 异常工况, 柴油水含量, 装置能耗

Abstract:

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.

Key words: vacuum dehydration, diesel hydrogenation unit, liquid ring vacuum pump, vacuum dehydration tower, abnormal working conditions, water content of diesel, unit energy consumption