炼厂脱硫联合装置适应性改造及运行

Adaptive Revamping and Operation of Refinery Desulfurization Plant

惠州炼化脱硫联合装置主要有加氢干气、加氢低分气、催化焦化干气、加氢液化气、焦化液化气及催化液化气脱硫单元,催化液化气、焦化液化气脱硫醇单元,胺液集中再生单元。首次开工以来,脱硫后的净化干气、液化气的H2S含量合格率低,净化加氢液化气合格率仅为7%。主要原因是原料H2S含量高于设计值和MDEA溶剂再生塔原始设计负荷不足,经过两次对MDEA溶剂再生系统改造,实现了净化干气、液化气产品合格率达到100%,每月降低催化液化气、焦化液化气脱硫醇单元碱液消耗15t,减少碱渣排放30t。因夹带MDEA富液和含有少量H2S,固定床精脱硫剂硫容小、抗波动能力差,导致精制加氢液化气铜片腐蚀合格率低。增加液化气水洗罐未彻底解决问题,将加氢液化气水洗改为碱洗,停用固定床精脱硫罐,铜片腐蚀合格率达到100%,生产成本降低90%。但是,碱洗系统补碱和碱液浓度还不能实现自动控制,需要继续改进。

The main units of CNOOC Huizhou Refining and Petrochemicals Company ′s desulfurization plant include a hydrogenation dry gas,hydrogenation low-pressure splitter gas,catalytic coking dry gas,hydrogenation LPG,coking LPG and catalytic LPG desulfurization unit,catalytic LPG and coking LPG sweetening unit and liquid amine regeneration unit.Since the plant became operational,the percent of pass in relation to H2 S contents of purified dry gas and LPG after desulfurization was low,with that for purified hydrogenation LPG being only 7%.The main reasons are the H2 S content of the feed is higher than the designed value and the original designed load of the MDEA solvent regenerator is insufficient.After two revamps of the MDEA sol-vent regenerating system,the percent of pass of purified dry gas and LPG reached 100%.As a result,alkali liquor consumption in the catalytic LPG and coking LPG sweetening unit dropped by 15 tons per month and alkali residue discharges fell by 30 tons per month.Due to MDEA-rich liquor entrainment and low content of H2 S,the sulfur capacity of the fixed-bed deep desulfurization agent is low and its ability to resist fluctuation is weak,resulting in low percent of pass for copper corrosion of hydro-treated LPG.The issue was not re-solved after addition of an LPG washer.The percent of pass for copper corrosion reached 100% and cost of production fell by 90% after hydrogenation LPG wash was changed to alkali wash and use of the fixed-bed deep desulfurization tank was stopped.However,further improvements are needed as alkali replenishing and alkali liquor concentration of the alkali wash system still cannot be automated.