PSA unit
PSA unit
(OP)
Does anyone can provide me the frequent problems that occur for the PSA unit as a new PSA unit is to be built in a new plant.
From your experience, there are some major problems with the design or operation of PSA that I would like to know.
Also, from safety point of view, what are major things to be considered in the design or the installation of this unit.
Sorry for giving a generic subject, but I am after major concerns of such unit so for having proper design of our new PSA unit.
Regards to all
From your experience, there are some major problems with the design or operation of PSA that I would like to know.
Also, from safety point of view, what are major things to be considered in the design or the installation of this unit.
Sorry for giving a generic subject, but I am after major concerns of such unit so for having proper design of our new PSA unit.
Regards to all





RE: PSA unit
Many adsorbants will pull water vapor from the gas stream. PSA will not remove this on the depressurization cycle, it takes added heat to cook the water off. The biggest problem I've had with PSA units is that they can quickly get so saturated with water that they don't have room to attach the material you are trying to remove.
I've found this to be a slightly bigger problem than the adsorbent material migrating downstream, but that is a problem as well.
David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
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RE: PSA unit
Like I said, the valves are the only moving parts, so since they will switch very frequently you can expect the most problems will be at the valves.
I know that there are PSA-unit manufacturers who took this problem into consideration and design the unit in this way that when there is a valve problem, that particular adsorber is switch off the process and the unit continous with producing on the adsorbers who are still in operation. Ofcourse this will change the adsorbtion time, which gives an increase of tailgas, but at least it's better than no production at all.
Ofcourse the control of the regenerationgas is importent, because, no good regeneration will give problems with the production and an efficiency that reduces.
Also it sometimes occurs that filters/flame arresters in the blow-off of the adsorbers are glogged by dust from the adsorbers. During the pressure relief at the end of the cycle dust is withdrawn from the adsorbers.
Cryotechnic
RE: PSA unit
RE: PSA unit
if the tail gas is entering a compressor be sure to put a filter (dual) at the inlet to collect adsorbent and prevent damage to the commpressor.
regards,
roker
RE: PSA unit
RE: PSA unit
Cheers,
RE: PSA unit
Now for some unregular problems. Our vessels are about 20 years old. This year we have found cracks in two different vessels. The first crack we found penetrated the wall, the second did not, but almost. The cracks developed from some improper welding on the outside of the vessels. Fortunately, on PSA vessels, cracking is the typical failure mechanism and does not result in a catostrophic failure. The welding was performed by a local contractor, not the vessel fabricator, for an insulation ring near the top of the vessels. The other vessels have been thouroughly inspected and found to be in good shape.
RE: PSA unit
roker
You brought good point but which type of compressor you mean
Is it only applicable for centrifugal type?
Regards
RE: PSA unit
Greetings,
Cryotechnic
"Math is the ruler of your potential succes...."