Hello everone,
In the pressure swing adsorption hydrogen production process, why is the adsorption pressure within 0.6-3MPa? Can the adsorbent reach its saturated adsorption capacity under this pressure? Or does this adsorption pressure have other meanings?
Thanks for your reply!
Adsorption processes are governed by adsorption isotherms. An adsorption process operation involves temperature variation (TSA) or pressure variation (PSA). Adsorption takes place in a condition in which adsorption of desired or unwanted species are adsorbed and regeneration in a condition in which adsorbed materials are desorbed.
Zheng Gao
Let's imagine that you have adsorbed molecules of hydrogen and butane. The gas pressure above the adsorbent depends on the molar mass of the molecules. Hydrogen is made up of lighter molecules than butane and therefore will leave the high pressure reactor earlier than butane. Butane will escape at less pressure. The change in pressure depends on the composition of the mixture of hydrogen with other gases. The less the molecules of the mixture differ in molar mass, the greater the pressure difference should be.In the separation process, it is necessary to achieve optimal separation, not a saturated adsorption layer. This process can take place in non-equilibrium conditions.
Article Purification of Hydrogen by Pressure Swing Adsorption
A H2 PSA will adsorb the contaminant at about 300-350 PSIG (~100-500). The product H2 (99+ % H2) is slightly lower than feed pressure and the off gas product is typically
The amount of adsorbed gas increases with increasing pressure. The limitation is capillary condensation and costs. And that's all.