富氢气体中回收氢气技术

Technology for Recovering Hydrogen from Hydrogen-rich Gas

加氢裂化装置副产的富氢气体,氢气纯度为85.41%。原设计改入制气装置作为原料补充,但实际生产过程中,由于富氢气体中硫含量在20～500μL/L之间大幅波动,易造成制氢脱硫反应床层穿透,使转化催化剂发生硫中毒;富氢气体中氢气含量较高,易造成制氢加氢催化剂发生反硫化反应,使加氢催化剂失活。因此将这部分气体改入燃料气系统。结合长庆石化公司生产实际,利用现有生产负荷较低的PSA装置和溶剂再生装置,将加氢裂化富氢气体和重整装置的富氢气体混和后,再经脱轻烃、脱硫预处理,预处理后的富氢气体改进PSA装置提纯出99%(体积分数)的氢气,作为加氢裂化装置的补充氢源。氢气资源得到充分利用,既节约了制氢装置天然气用量,又提高了公司管网燃料气热值,还回收了部分液化气组分和硫磺,降低了环境污染,年实现经济效益600万元。

The hydrogen purity of hydrogen-rich gas from the hydrocracking unit as a byproduct was 85.41%.The gas was originally designed to enter a hydrogen production unit to replenish feed gas.However,in actual production,as the sulfur content of the hydrogen-rich gas flucutated dramatically between 20 and 500μL/L,this could easily cause penetration in the bed layer of the hydrogen-generating and desulfurizing reactor,in turn resulting in sulfur poisoning of conversion catalyst.The high content of hydrogen in the hydrogen-rich gas could easily trigger devulcanization of the hydrogenation catalyst used in hydrogen production,in turn inactivating the hydrogenation catalyst.This gas was therefore introduced to the fuel gas system.Taking into account the context of PetroChina Changqing Petrochemical Company’s production conditions and taking advantage of the PSA and solvent regenerating units,which were operating at low capacities,technicians decided to blend the hydrocracked hydrogen-rich gas and the hydrogen-rich gas from the reforming unit.The gas blend undergoes a pretreatment process,in which light hydrocargon and suflur are removed,before entering the PSA unit for purification.The purified hydrogen,with a purity of 99%(by volume fraction),is used to replenish the hydrogen feed for the hydrocracking unit.This modification to the company’s hydrogen utilization process allows hydrogen resources to be fully utilized-on the one hand,it reduces hydrogen consumption by the hydrogen produciton unit and raises the heat value of fuel gas in the company’s pipeline network,and on the other hand,it reduces pollution to the environment as part of LPG components and sulfur is recovered.As a result,annual economic returns from these measures reach six million yuan.