溶剂再生塔顶DCS引压阀结晶原因及整改措施

Causes analysis of crystallization of pressure impulse valve in DCS of solvent regeneration tower overhead and improvement measures

中国石油天然气股份有限公司乌鲁木齐石化分公司炼油厂300 t/h溶剂再生装置在运行过程中再生塔顶DCS引压阀PI-20901经常出现结晶,再生塔压力不能正常显示,严重影响了装置的正常操作,取样化验分析主要为铵盐结晶物。借鉴同类装置经验,采用上游气体脱硫装置注水降氨,溶剂再生装置增设塔顶空冷注水脱氨、增设提浓线保溶剂罐液位平衡等技术改造,从根本上降低了溶剂系统中的氨浓度,使溶剂再生酸性气中的氨质量浓度从847 mg/m3降至123 mg/m3,减少了溶剂塔顶产生铵盐结晶的可能性,使再生塔塔顶DCS引压阀结晶频率从每月1次降低到了每3个月1次,确保了装置"安稳长满优"运行。

The 300 t/h solvent regeneration unit in the refinery of PetroChina Urumqi Petrochemical Company experienced frequent crystallization in the pressure impulse valve PI-20901 in the DCS system of sol- vent regeneration tower overhead in operation. During crystallization, the normally display was impossible, which has seriously affected the normal operation of the unit. The sampling analysis confirmed that the crystallization is mainly by ammonia salt. With the experience of the similar unit in solving the similar problems, the following revampings have been implemented such as water was injected to reduce ammonia in the up-stream gas desulfurization unit, the water injection was also added in tower overhead air cooler of solvent regeneration unit and installation of solvent concentration line, etc, which have reduced the ammonia concentration in solve system and lowered the ammonia in the sour gas of solvent regeneration system to 123 mg/m^3 from 847 mg/m^3. All these have minimized the possibility of crystallization in solvent system and crystallization frequen- cy of impulse valve in the DCS system of solvent regeneration tower overhead to 1 time a month from 3 times a month. The safe stable operation of the unit has been ensured.