加氢装置循环氢系统铵盐堵塞原因分析及处理

Analysis of causes of ammonium salt deposition in hydrogen recycle system of hydrocracking unit and treatment

北京燕山分公司1.3 Mt/a中压加氢裂化装置由于重整装置供氢含氯(新氢中氯化氢体积分数约5μL/L)导致循环氢压缩机出口至反应产物/循环氢换热器入口管线发生严重的氯化铵结晶堵塞,反应系统压力降由1.23MPa上升至1.71 MPa,循环氢进反应加热炉流量由110 dam3/h降低至90 dam3/h,反应供氢不足。为应对这些问题而采取了降低装置循环氢中氯化氢和氨的浓度、铵盐加热升华、流量脉冲式冲击等在线处理措施,取得了较好的效果。介绍停工检修期间对管线的水洗过程及水洗后的管线脱水方法,提出了加强对新氢及原料中氯离子检测,保证装置长周期运行的建议。

As the catalytic reformer hydrogen for the 1.3 MM TPY medium pressure hydrocracking unit in SINOPEC Beijing Yanshan Company contains chlorine （the volume percentage of hydrogen chloride in fresh hydrogen is about 5 μL/L）,the piping from discharge of recycle hydrogen compressor to the inlet of reactor effluent/recycle hydrogen heat exchanger is seriously plugged by crystallized ammonium chloride.The reactor system pressure drop is raised from 1.23 MPa to 1.71 MPa,the flowrate of recycle hydrogen to reactor furnace goes down to 90 dam3/hr from 110 dam3/hr,and hydrogen required for the reactor is in insufficient supply.To solve these problems,effective on-line treatment measures have been taken such as reduction of hydrogen chloride and ammine in recycle hydrogen,heating of ammonium salt and application of flow pulse impingement,and good results have been achieved.The water washing process of the pipeline during unit＇s shutdown for maintenance and water removal method after water washing are introduced.It is recommended that the testing of chlorine ions in fresh hydrogen and feedstock shall be strengthened to ensure the long-term operation of the unit.