On the recovery of hydrogen from methanol synthesis purge gas

It’s molecular sieves; hydrogen molecules are small enough to pass through the recovery membrane. The principle is quite simple: it’s just filtration!

This post was last edited by Sichuan Q on 2011-9-5 at 13:47. The Prison membrane, which is distributed by our company, operates on the principle that different gas components have varying rates of dissolution and diffusion within polymer materials; as a result, under the influence of pressure differences on both sides of the membrane, these components permeate through the membrane walls at different rates, thereby enabling separation. The driving force (the partial pressure difference of the corresponding components on both sides of the membrane), the membrane area, and the separation selectivity of the membrane constitute the three key elements of membrane separation. Based on the rate at which gases permeate through a membrane, gases can be divided into \"fast gases\" and \"slow gases\". Among common gases, H2O, H2, He, H2S, etc. are referred to as \"fast gases\"” ； Those referred to as \"slow gases\" include CH4 and other hydrocarbons, N2, CO, Ar, etc. The shell of the membrane separator is similar to that of a shell-and-tube heat exchanger, and it contains tens of thousands of tiny hollow fiber filaments. The advantage of hollow fibers is that they enable the largest separation area to be achieved in the smallest volume, resulting in a compact and efficient separation system; moreover, they can withstand large pressure differences with their thin fiber walls. After entering the shell side of the membrane separator, the mixed gas flows along the outside of the fibers. By maintaining an appropriate pressure difference between the inside and outside of the fibers, the gas is driven by this pressure difference: the faster-moving gas (hydrogen) selectively passes through the membrane walls preferentially, accumulating on the low-pressure side of the tube and being discharged from the membrane separation system as the permeate (product gas). The gas with a slower permeation rate (hydrocarbons) remains on the non-permeate side, where the pressure is almost the same as that of the feed gas; it is then sent out of the system after being depressurized and cooled. The process flow of this separator system is simple (it only includes the pretreatment and membrane separation stages) ； With almost no moving parts, it requires minimal maintenance and offers reliable operation ； Driving and parking are convenient and fast ； Moreover, the Prison membrane has a long lifespan, usually exceeding ten years. It is being used more and more widely in industries such as ammonia synthesis and methanol production.

It is the Pristine hydrogen technology; hydrogen diffuses more rapidly than other components in the off-gas, so by using a membrane separator, hydrogen of high concentration can be obtained.

The details on floor 3 explain that the driving force is the pressure difference; the hydrogen content in the recovered gas is not high enough to be used as high-purity hydrogen, so it can only be returned to the system as a usable gas

Reply 6# yuanjia0130: Use pressure swing adsorption.