Regarding the voltage equalization issue?
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During PSA pressure equalization, the ideal situation is to achieve pressure equalization each time. What is the theoretical basis for such a requirement? Thank you!
Under normal conditions, the voltage equalization requirements can be met~~ The purpose of voltage equalization is to recover the gas in the dead space and improve the yield~~
I mean, why does it have to be evened out? Thank you!
Do you mean that equalizing A and B to the same pressure is called leveling? Let me give an example: if the adsorption pressure of set A is 0.5 MPa, and when the pressure in set B is reduced to 0.3 MPa, the switching begins, and the inlet valve of set B opens instantly. In other words, the pressure in set B will also rise to 0.5 MPa instantly, which will have an impact on the adsorption bed; the magnitude of this impact depends on how much pressure is applied. So the voltage balancing needs to be even.
Why not level it out? Your goal is to find every possible way to make use of the stagnant air in the bed layer; equalizing pressure and distribution is the means to maximize this utilization~
Voltage equalization is indeed aimed at recovering the effective components in the dead space to improve the yield. Are there any other reasons? For example, regarding the impact on purity, I want to find some theoretical basis for it. Thank you!
There is no other reason; it’s simply to increase the yield. By \"pressure equalization,\" it means balancing the pressure in the two adsorption towers. There are discussion posts on the calculation methods for these pressure equalization pipelines, and the basis for such calculations is that the final pressures should be equal (selecting an appropriate pipe diameter within a specified time frame makes the calculations complex). I’m not sure what’s bothering you. Purity has nothing to do with voltage equalization; the purity of the product depends on the adsorption time and the penetration point. It is recommended that you find some books or materials on adsorption and read them for yourself.
Let me share my personal opinion: Pressure equalization is necessary to take into account the pressure difference before and after the inlet valve. Without such equalization, if the pressure difference is too large, opening the inlet valve will cause a significant shock to the molecular sieve bed; repeated such shocks can damage the molecular sieve bed. This applies to inlet and outlet valves that are butterfly valves, as there is no requirement regarding the pressure difference before and after them. Some molecular sieves use three-bar valves; they cannot be opened when the pressure difference before and after is too large, and this is also why it is necessary to equalize the pressure in molecular sieves.
The original poster is discussing the voltage equalization issue in PSA units; large pressure differences and the opening and closing of valves are common in PSA systems~~
Multiple pressure equalizations are carried out to recover the remaining gas in the bed. An uneven pressure distribution can lead to inconsistencies in the pressure drop and pressure rise; this has little impact on the purity of the product, but it results in a lower yield. And thus, the purpose of voltage equalization is lost
In the field of oxygen production, it is not possible to achieve the same pressure; the speeds are different~