combination of air dryer materials..
- Thread starter cosmic
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Why would you want to?? MS is FAAAAR superior in every aspect of air filtering. Good place to get it: https://www.deltaadsorbents.com/ Get 4A 8-12mesh. Same size as what's used in most filter cartridges.
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Most dryers use Zeolite 13x molecular sieve. You could “salt” the Zeolite with a small amount of the color changing silica beads to make it easier to see when to change out the Zeolite.
From one of my previous posts.
Well, I could say because that’s what Joe B recommends. But 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.
Now for the science speak…
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
From one of my previous posts.
Well, I could say because that’s what Joe B recommends. But 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.
Now for the science speak…
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
You might try this, already has color changing beads. https://www.amazon.com/gp/product/B07CJXDBV2/ref=pe_253590_291545930_em_1p_4_ti
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I also use color-indicating beads but I only put a small quantity next to the outlet of the filter. The beads are sandwich between two thin layer of the cotton-like filter material that came with the gold filter. The color of the beads was slightly on the purple side when it came indicating that it has already absorbed a small amount of water. After using it the filter for some time, it's color changed to blue , seems that the 13X has sucked water out of it.
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yes, this one has combine silica desiccant and molecular sieve together.
https://www.aliexpress.com/store/product/4500PSI-air-compressor-filter-water-oil-separator-absord-moisture-filter-absord-water-filter/2305020_32891857578.html
https://www.youtube.com/watch?v=6SjoTB4btJY
https://www.aliexpress.com/store/product/4500PSI-air-compressor-filter-water-oil-separator-absord-moisture-filter-absord-water-filter/2305020_32891857578.html
https://www.youtube.com/watch?v=6SjoTB4btJY
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This web page compares molecular sieve and silica gel in terms of their water absorption performance. It appears that molecular sieve is a better choice because of it's higher rate of absorption and absorption capacity at elevated temperature ( compressed air is hot ) : https://www.sorbentsystems.com/desiccants_charts.html
Regarding the concern over the release of acid by molecular sieve, I take it with a grain of salt. A common practice is to use another plastic tube to isolate the acid from the inner surface of the aluminium filter tube but my question is if acid is really produced, will it be possible for the acid to be carrying by the air flow to the unshielded parts of the filter tube such as the threads which is likely to be the first point of failure ? In my set up , the molecular sieve is allowed to come into direct contact with the inner surface of the filter tube and I am going to check the internals regularly to see if corrosion is a real problem.
Perhaps a more relevant concern is how tight the molecular sieve material is packed together. I am convinced that if there is too much space between the molecular sieve balls, the majority of air will just go around the balls instead of through them so the effectiveness of water absorption will be lower. At present I am using 13X balls of diameter 1.6 ~ 2.5 mm and it is possible to get smaller 5A balls of diameter 0.4 ~ 0.8 mm. I have not tried it yet because I am yet to come up with a way to objectively compare the results.
Regarding the concern over the release of acid by molecular sieve, I take it with a grain of salt. A common practice is to use another plastic tube to isolate the acid from the inner surface of the aluminium filter tube but my question is if acid is really produced, will it be possible for the acid to be carrying by the air flow to the unshielded parts of the filter tube such as the threads which is likely to be the first point of failure ? In my set up , the molecular sieve is allowed to come into direct contact with the inner surface of the filter tube and I am going to check the internals regularly to see if corrosion is a real problem.
Perhaps a more relevant concern is how tight the molecular sieve material is packed together. I am convinced that if there is too much space between the molecular sieve balls, the majority of air will just go around the balls instead of through them so the effectiveness of water absorption will be lower. At present I am using 13X balls of diameter 1.6 ~ 2.5 mm and it is possible to get smaller 5A balls of diameter 0.4 ~ 0.8 mm. I have not tried it yet because I am yet to come up with a way to objectively compare the results.
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Great to know about the 13x. 5lbs. from Delta is only around 40bux. https://www.deltaadsorbents.com/13x-8x12-molecular-sieve-desiccant
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After further study the MS is can not be regenerated at home.. It needs a vacuum chamber and 500 C (950 F) temps..
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@cosmic, even if it could be regenerated at home, why bother? When you can buy a couple pounds for $20, and you only use a couple ounces each time you change it out, and you change it out maybe twice a year (if that), that couple of pounds will last many many years...
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I agree with you about the fallacy of zeolite acid release. It is only claimed by one vendor who has a sales motive for saying so. No third party research has shown that water adsorbed by zeolite causes acid induced corrosion on anodized aluminum.
The purpose of adding a small percentage of silica gel beads to zeolite or alumina desiccant is to indicate that the desiccant needs replacement or recharging since the tan beads won't change appearance as they adsorb water vapor. This is not a mis-spelling. Zeolite and alumina beads filter and adsorb (attach) water vapor molecules within openings in their internal crystal structure. Cotton tampon inserts and silica gel beads absorb moisture like a sponge absorbs water.
You may reconsider using a tiny desiccant bead size. 13X zeolite is universally sold in 4x8 (1/8”) and 8x12 (1/16”) mesh sizes. The 8x12 and 4x 8 mesh sizes are used in commercial diving filter cartridges sold by Coltri, Bauer, etc. Zeolite 13X in 20x40 mesh size would be .4mm-.8mm bead size. The 3,4,5, and 13X zeolite desiccants refer to the desiccant's filtration purpose instead of a bead size. Each numbered zeolite has different crystal opening sizes to capture different gases or liquids having different molecule sizes. https://www.deltaadsorbents.com/13x-molecular-sieve
A high pressure filter properly filled with zeolite 13X and a pressure maiintaining valve will not channel moisture to a tank bypassing all of the adsorbant. Air channeling and zeolite acid leeching is marketing strategy intended to sell one vendor's brand of filters. There are hundreds of Tuxing and Xin Yong Shi Gold filter users and Diablo filter users and there aren't reports that gold filters are internally corroding or channeling water vapor into air tanks.
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Am I the only one that noticed that the corrosion in the tube from the acid leaching is not a anodized tube....
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Can you post some pictures ? I would like to get a feel of how bad the corrosion is visually.
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Since the silica is less efficient than the molecular sieve, using it in with the sieve really only indicates the silica is full, not the sieve...So how do we know it’s time to change the sieve?
Should it be based on run time?
Should it be based on run time?
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Absolutely. I cnange the desiccant in my filter after 20 hours based upon my hour meter. The silica beads are an indicator not an absolute.
Just to clarify, I believe Cosmic is saying that the one report that showed a corroded aluminum tube was one that was unprotected aluminum and was not anodized. The gold filters and the Diablo filters are anodized. In the photo of the corroded tube I don't recall that the type of desiccant used was even mentioned.
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