炼厂氢气资源优化浅谈

随着炼厂氢气耗量的不断增加,需要选用低廉的制氢原料,采用合理的制氢工艺技术,满足炼厂氢气需求.比较变压吸附、膜分离、深冷分离三种氢气提纯分离技术,对加氢等装置尾气中低浓度氢进行回收利用,能够合理利用氢气资源,有效降低生产成本.某炼厂选用焦化干气制氢后,与轻油制氢相比,原料成本下降,氢气纯度提高.根据各用氢装置的用氢压力、用氢量进行匹配,采用从高压到低压的一次通过式流程,只设置一台新氢压缩机,氢气逐级利用.不仅提高了氧气资源利用率,而且有效降低了炼厂综合能耗.采用PRISM膜分离器,从高达10MPa压力的冷高压分离器排放尾气中回收提纯氧气,回收提纯的氢气再回到新氢压缩机的三级人口升压后循环使用.废氧进行胺液脱H2S处理后,采用PSA技术进行废氢回收利用,PSA副产品解吸气升压后作为制氢装置的原料,节约了生产成本.

A Brief Discussion on the Optimization of Refinery Hydrogen Resources

As the use of hydrogen in refineries increases,there is a need for introducing lower prices of feedstock for producing hydrogen.Also,appropriate hydrogen production technology is needed to meet refineries′ hydrogen demand.Hydrogen purification and separation techniques such as pressure swing adsorption,membrane separation and cryogenic separation can be used to recover the low-concentration hydrogen in the tail gas from hydrogenation and other units.This can effectively reduce production costs.After the introduction of coker gas in hydrogen production,a refinery′s feedstock cost dropped and purity of produced hydrogen improved compared to the method of using light oil to produce hydrogen.Based on the hydrogen pressure and consumption of each hydrogen unit,the refinery adopted a once-through process from high pressure to low pressure with only one fresh hydrogen compressor used.The hydrogen is used in a cascade manner.This has not only raised the utilization rate of hydrogen but has also effectively reduced the overall energy consumption of the refinery.The PRISM membrane separator was used to recover and purify hydrogen from the tail gas emitted by a 10MPa cold high pressure separator.The hydrogen recovered and purified is returned to the third-stage inlet of the fresh hydrogen compressor for pressure boosting before reuse.The waste hydrogen is treated in the amine H2S-removing process and recovered using the PSA technology for reuse.Desorption gas,a PSA byproduct,is used as the feedstock for hydrogen units after going through the pressure boosting process.This further reduces production costs.