We have installed a new air dryer to supersede the old one, however the new air dryer suffers from higher pressure drop and the dried air contains a lot of condensate. So, what is the best selection criteria for the fixed bed Silica Gel air dryer?
Over many cycles of drying and regeneration, silica gel has a tendency to turn powdery and the pressure drop goes up tremendously. But that should not be the problem in freshly charged dryers. I assume that the old and new dryers are geometrically identical. If so, in the new dryer, are you using finer particles than before?
In the dryer, as a result of removal of water vapor from the air, heat is generated. Therefore, condensate in the dryer comes as a complete surprise. Does your air come from a reciprocating compressor? It looks to me that the drain from the compressor's receiver is blocked and the water accumulating in the receiver is being carried along with the air into the dryer. Please check that. To me, it appears that your problems are not due to selection criteria of the dryer!
Thanks ,Vijay
The old air dryer capacity is (365 scfm) which reveals that, it is undersized the new air dryer (250 scfm), the air compression piping network was checked o.k., therefore, my question now, is the flow capacity the only selection criteria or there are other parameters, and how current situation can be solved without removal the new one?
Hi Mr.Said,
I have worked with dessicant dryer few years back. From my experience, even the temperature and the pressure of the compressed air going in to the dryer play a part in the dryer performance. We had a similar problem in a relatively new dryer of 1000SCFM. The diagnosis revealed that the pressure and temperature(going in to dryer) are not maintained as decribed in the dryer manual. If the pressure is not maintained at dryer inlet, then check for the air consumption and leakage at the user end.
USE Psychometric chart to determine the condition of the air before and after the drier...well if the pressure ,temp., and humidity meets your requirement then your drier is o.k
Hi ,all
Thanks to Bharathy and Mohammad
The pressure and temperature at the air dryer inlet are maintained without any changes between the two installations. Can you group the key performance parameters such that new air dryer is correctly selected ?
Your air consumption (load) downstream of the dryer is greater than the volume of air you can treat (dry). The dryer is then "choking" the flow and hence the big pressure drop. The dryer is undersized and the only solution is to analyze if any of your downstream uses can be met by a by-pass arrangement with a enough volume to get the dryer within specs. The other solution is get another dryer and branch your supply in a balanced manner (parallel dryers preferably of same capacity) or a branch supply with its own dryer sized for load. Unless you removed loads, the old dryer gave you a minimum need and maybe only needed help if you were increasing loads.
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