绿色甲醇项目中弛放气氢回收工艺的选择

Selection of Bleed Gas Hydrogen Recovery Process in Green Methanol Project

绿色甲醇工艺中弛放气的组成与常规的合成气制甲醇工艺有巨大的差异,开展绿色甲醇弛放气氢回收工艺对比研究,寻找出一种优化的氢回收工艺是一项十分必要和有意义的工作。对绿色甲醇项目中弛放气两种主要的氢回收工艺——膜分离和变压吸附(PSA)进行工艺和经济分析对比。研究发现变压吸附在产品氢纯度、氢气回收率方面优于膜分离。变压吸附工艺可获得纯度达99.9 mol%的氢气,同时还可以实现二氧化碳全回收,而膜分离无法实现。从投资和运行成本对比,膜分离优于变压吸附,在对氢气纯度没有特殊要求情况下,宜选择膜分离工艺。

The composition of sag gas in green methanol process is very different from that in conventional synthesis gas methanol process.It is necessary and meaningful to carry out a comparative study on the hydrogen recovery process of sag gas in green methanol and find out an optimized hydrogen recovery process.Two main hydrogen recovery processes,membrane separation and pressure swing adsorption(PSA),were analyzed and compared in the green methanol project.It was found that pressure swing adsorption was superior to membrane separation in hydrogen purity and hydrogen recovery.The pressure swing adsorption process can obtain hydrogen with a purity of 99.9mol%,and can also achieve full recovery of carbon dioxide,which is impossible to achieve membrane separation.In terms of investment and operating cost,membrane separation is better than pressure swing adsorption,and it is appropriate to choose the membrane separation process when there is no special requirement for hydrogen purity.