Acid Free 3A Zeolite Alternative

[T3PRanch]

I believe I have found a 3A Zeolite alternative that overcomes the biggest potential problem with Zeolite which is acid production when saturated. The new adsorbent is Activated Alumina. "It is an excellent desiccant for liquids and gases and can achieve dew points from -40°F to -100˚F depending on the operating conditions and the design of the dryer." 

https://www.deltaadsorbents.com/SDS-Specs/Silica-Gel-Desiccant-SDS-Specs/DelSORB-Activated-Alumina
https://www.deltaadsorbents.com/activated-alumina-f-200-18

Fairly inexpensive and completely reusable. Now we need an acid free indicator to mix with it and we are good to go.
I will order some soon to replace the Zeolite in my Diablo Filter.

Thurmond

 

[ravenlunatic]

Molcular sieve is acid free. I have looked through more pages than I care to enumerate, and nowhere did I find any reference to the production of acid when wet. It does produce a bit of heat when it gets wet, but in the small amount that we use, I think the risk is negligible. I did read that type 4A is used in soaps and some toothpastes as a foaming agent. (Replaced phosphates.) I hope this helps you save some money. 



Take care.



Mike

 

[airgunfans]

http://hengyeusa.com/community/activated-alumina-and-molecular-sieve

"..... Activated alumina has a real strong water adsorption capacity, it can adsorb a lot more water than molecular sieve, this makes it a very useful material in air compressors ..... The durability of the material allows it withstand a lot of pressure along with high levels of humidity......."

Really sounds better but I am not sure how we can tell whether the air going into our guns / tanks is drier after switching to activated alumina .

Both molecular sieve and activated alumina are so cheap that I wont bother to regenerate them. 

 

[T3PRanch]

Molcular sieve is acid free. I have looked through more pages than I care to enumerate, and nowhere did I find any reference to the production of acid when wet. It does produce a bit of heat when it gets wet, but in the small amount that we use, I think the risk is negligible. I did read that type 4A is used in soaps and some toothpastes as a foaming agent. (Replaced phosphates.) I hope this helps you save some money. 



Take care.



Mike

Molecular sieve has one of 3 makeups. Each has either calcium, potassium or sodium cations involved. Under the wrong conditions these reactive metal ions make a corrosive liquid that can attack the usual aluminum vessel that contains the sieve. Just plain chemistry.

On the other hand molecular sieve which has a lower water saturation capacity than Activated Silica it is less dependent on partial water pressure which lets a dryer air be produced by the molecular sieve (zeolite). Knowing this, certain design changes in the drier can be made to minimize issues that might arise because of the different isotherms of each adsorbent. 

 

[airgunfans]

Just talked to a number of vendors selling activated alumina. Many have mentioned the issue of beads turning into powder over time. Can be an issue if those powder find ways to valves in the airtube of guns.

 

[Centercut]

Two words. Zeolite 13x

 

[bandg]

A little expansion on your two words would be helpful.

 

[Centercut]

@bandg, expansion of two words below:


I did some research and that’s what dive shops use in their filtration towers for moisture removal. Additionally, it has approx. a 10 Angstrom pore diameter compared to 3A, 4A, or 5A which makes it more suitable for trapping water molecules.

Molecular Sieve 13X is a multiple purpose, highly porous, high capacity alkali metal alumino-silicate in the spherical form. It is the sodium form of the Type X crystal structure with pore diameters of approximately 10Å. It can adsorb all molecules that can be adsorbed by 3A, 4A, and 5A molecular sieve. Type 13X molecular sieve can also adsorb molecules such as aromatics and branched-chain hydrocarbons, which have large critical diameters.

I'm of the opinion, and I couldn't find any research to dispute it, that the "it'll form acid and eat through your aluminum "gold" filter" is a made up story to sell the much more expensive filters and cartridges. I've put over 8 hours run time on mine, and when I took it apart it looked like new inside. The threads and interior surfaces had ZERO wear, and ZERO corrosion. And that's with the first inch of the cotton tampon being a dark color that has obviously absorbed some moisture and contaminates....

 

[T3PRanch]

None of the mentioned Activated Alumina or Zeolites will present a problem on a well maintained system. The zeolites can be an issue when the system is not maintained as a worst case scenario. All can experience a breakdown of the clay binder also in a worst case scenario and pass powder downstream. I personally use a .5 um millipore filter in a 10,000 psi housing as a final particle filter.