重整装置预加氢单元压降增大原因分析及对策

Causes of Higher Pressure Drawdown at Pre-hydrogenation Unit of Reformers and Countermeasures Analysis and Countermeasures

九江分公司催化重整装置由于用氢流程的安排、预加氢增压机能力、原料杂质、系统的含铁物质等原因,预加氢反应系统存在压降上升过快现象,影响了装置长周期稳定运行。由重整原料油氯含量相对较高引起的铵盐沉积,预加氢反应器入口处的低压操作(1.70～1.75MPa)和气油体积比的低限操作(100)加速了催化剂的生焦积炭,这些因素不仅影响装置的处理量,而且引起重整系统压力上升,致使重整反应深度降低、产氢减少,成为限制重整装置稳定运行的瓶颈。通过对反应器顶部催化剂床层的"撇头"、氮气吹扫处理,再对空冷器E106和水冷器E107进行热水冲洗,并在反应器顶部装填级配剂后,预加氢反应系统总压降由0.48MPa降至0.2MPa。

Dut to a combination of factors such as the arrangement of hydrogen usage process,pre-hydrogenation booster＇s eapacity,feedstock impurities and the existence of iron-bearing substances in the system, the pressu re drawdown of the pre-hydrogenation system of the catalytic reforrming plant of SINOPEC Jiujiang Company increased too fast.This has affected the unit＇s long-term operational stability.Ammonium salt deposits,a resuh of high content of chloride in reforming feedstock,the low-pressure operation at the inlet of the pre-hydrogenation reactor（1.70-1.75MPa） and the lower-limit operation（100） of gas-oil volume ratio have accelerated the coke formation in catalysts.These factors not only affect the processing capacity of the unit but also raise the pressure in the reforming system,thereby reducing reforming reaction depth and hydrogen output.They will pose restraints on the stable operation of the reforming plant.Technicians took a series of measures to remove these hottlenecks including condueting skimming and nitrogen purge treatment to the catalyst bed at the top of the reac.tor,purging air cooler E106 and water cooler E107 with hot water and loading grading agent at the top of the reactor.After these measures,the total pressure drawdown of the pre-hydrogenation system dropped to 0.2MPa from 0.48MPa.