Does PSA molecular sieve react and become deactivated when exposed to CO2, releasing heat in the process?
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When we started up the PSA unit for the concentration of gas after CO conversion, we found that the temperature at the PSA outlet was as high as 70 degrees. After communicating with Dakota, they said that CO2 had penetrated into the molecular sieve and reacted with it, releasing heat; this caused the molecular sieve to become deactivated. Has anyone encountered this situation? Is this the reason?
Did they not teach you how to drive? The issue of carbon dioxide penetration might not be a big problem; what’s concerning is water penetration. PSA outlet at 70°C has never been encountered.
What material is the molecular sieve made of? Carbon dioxide will react with it
You can adjust the adsorption time and try again.
Physical reaction: strong adsorption with heat release, and it can also be activated and regenerated
When the partial pressure of CO2 in the feed gas exceeds a certain value, it is not easy to completely desorb it after being adsorbed by molecular sieves, as molecular sieves have a high adsorption capacity for CO2; generally, the more easily an ingredient can be adsorbed, the harder it is to desorb it. If the over-temperature is as severe as described by the poster, a large amount of CO2 needs to be absorbed. During operation of the unit, the cycle time is under control; generally, no tower will absorb gas for an excessively long period of time, unless there is no operating program in place and gas is allowed to flow into a particular tower for an extended time.
This situation occurred during the initial startup of the hydrogen enrichment PSA unit; I had never seen it before, but it did not happen again afterward. The molecular sieve used is 5A molecular sieve, and its material is likely zeolite.