液化气脱硫组合工艺在长庆石化的应用

长庆石化原有一套液化石油气脱硫装置,设计处理能力为5.34×104t/a,设计处理加氢裂化液化石油气。2011年底,长庆石化连续重整装置建成投产,液化石油气处理量增大,该脱硫装置无法保证产品质量。为此,异地新建一套12.6×104t/a液化石油气脱硫装置,对原5.34×104t/a脱硫装置4台设备进行利旧,管道、仪表做相应改造,降低装置投资成本约40万元。新装置采用凝结水作为伴热介质,每年节约动力消耗30余万元。新装置采用"胺法脱硫+精脱硫"新工艺,充分考虑液化石油气夹带微量溶剂及溶剂易氧化变质等情况,增设液化石油气水洗水罐、过滤器和聚结器,将液化石油气携带出来的少量溶剂和微量杂质彻底清除分离后,进入精脱硫罐。精脱硫罐选用表面积大、孔道丰富、强度好、脱硫反应速度快和抗水能力强的DPS-2A新型高效精脱硫剂,通过物理吸附和化学反应,深度脱除硫化氢和部分硫醇。工业运行表明,"胺法脱硫+精脱硫"组合工艺成功解决了液化气铜片腐蚀不合格问题。

The Application of Integrated LPG Desulfurization Process in PetroChina Changqing Petrochemical Company

PetroChina Changqing Petrochemical Company＇s original LPG desulfurization unit had a designed processing capacity of 5.34×10^4t/a and was designed to process hydrocracked liquefied petroleum gas.At the end of 2011 ,Changqing Petrochemical put a continuous reforming unit into operation and the company＇s LPG processing capacity increased significantly.As the existing desulfurization unit was unable to ensure product quality,the company decided to establish a 12.6×10^4t/a new LPG desulfurization unit at a different location. Four devices of the original desulfurization unit were used in the new unit after an upgrade was completed on the ducts and instruments of the original unit.This reduced the capital investment in the new unit by about 400000 yuan.The new unit uses condensed water as the heat tracing medium.Annual power savings ex ceeded 300000 yuan.A new process ＂ammonia desulphurization ＋ fine desulfurization＂ was used in the new unit and the facts that trace volumes of solvents could be entrained in LPG and that solvents could easily oxidize were fully considered.An LPG wash water tank,filter and coalesce were added.After the small amount of solvent and trace amounts of impurities ,entrained by LPG, are removed and separated, LPG enters the fine desulfurization tank.In the fine desulfurization tank ,a new type of efficient fine desulfurization agent DPS-2A, which is characterized by large surface area,rich ducts,good strength,fast desulfurization reaction and strong water resistance ,was used.The desulfurizer can help effectively remove hydrogen sulfide and part of mercaptan through physical adsorption and chemical reactions.Industrial application shows that the integrated ＂ammonia desulphurization ＋ fine desulfurization＂ process is an ideal solution to copper strip corrosion of LPG.