Detoriation of silicagel/glass fibre rotor
Detoriation of silicagel/glass fibre rotor
(OP)
Dear all,
We are using a desiccant rotor for drying our compressed air. This rotor is build up of glass fibre paper, impregnated silica gel to adsorb moisture. The silica gel itself also acts as a binder to hold the glass fibres together.
After some time, we see that this rotor becomes soft and brittle. The rotor operates in conditions with temperatures up to 150°C during the regeneration phase and around 30°C during the adsorption phase.
Has anyone experienced similar reactions?
Has anyone an explanation for this phenomenon? Some already mentioned that a hydrothermal proces occured, but does this proces affect the silicagel or the glass fibre?
Many thanks in advance!
Best regards,
Max
We are using a desiccant rotor for drying our compressed air. This rotor is build up of glass fibre paper, impregnated silica gel to adsorb moisture. The silica gel itself also acts as a binder to hold the glass fibres together.
After some time, we see that this rotor becomes soft and brittle. The rotor operates in conditions with temperatures up to 150°C during the regeneration phase and around 30°C during the adsorption phase.
Has anyone experienced similar reactions?
Has anyone an explanation for this phenomenon? Some already mentioned that a hydrothermal proces occured, but does this proces affect the silicagel or the glass fibre?
Many thanks in advance!
Best regards,
Max





RE: Detoriation of silicagel/glass fibre rotor
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RE: Detoriation of silicagel/glass fibre rotor
His opinion is that our regeneration phase is not sufficient enough to dry the desiccant rotor completely (our calculations, simulations and measurement tell us the other thing).
Also according to our manufacturer, it is possible to wash the rotor with water.
I find this strange: if water is detrimental for the rotor (e.g. insufficient regeneration), why is it allowed to wash the rotor (dipping) in water?
RE: Detoriation of silicagel/glass fibre rotor
If the former, is there any chance that chlorides have contaminated/are contaminating your air system? Oil mist from compressor?
RE: Detoriation of silicagel/glass fibre rotor
The same SEM analysis didn't show any signs of chlorides, oils are impossible because of the oil-free compressor and filters (and also no oil was found in the SEM).
Is it possible that a combination of high temperatures (in the regeneration phase) and high humidities cause the deteroriation of the silica gel (or glass fibres), and in what way? What could be the physico-chemical reaction behind this phenomenon?
RE: Detoriation of silicagel/glass fibre rotor
RE: Detoriation of silicagel/glass fibre rotor
Less than 1% Na will cause the deterioration of glass fibre when heated above 140F.
RE: Detoriation of silicagel/glass fibre rotor
RE: Detoriation of silicagel/glass fibre rotor
Can I know what is the reason for going with a rotary dryer? How are you sealing the process and reactivation side? The cup seals used for sealing these two sides may not be very effective at higher pressures. PSA systems could have been economic.
RE: Detoriation of silicagel/glass fibre rotor
Thank you for your reply.
Regarding the operation of this type of rotary dryer, I can not go into detail.
You mentioned three types of desiccant detoriation, do you have an idea which one is the most agressive towards silicagel? Personally I think the combination of heat (150°C) and high humidity is the worst combination.
Are you familiar with the science behind this degradation proces?
Best regards,
Max
RE: Detoriation of silicagel/glass fibre rotor