Dry Shop Air - Step 1 (Compressor After-Cooler)

[MtnBiker]

I'm starting to feel inadequate with my puny 5hp compressor.

 

[MtnBiker]

My company may have to take notes from you guys . We have 23 IR and Atlas compressors thruout the plant , after coolers , dryers , drain alls , oil / water seperators and more coalescing filters than you can shake a stick at and we STILL get water in our lines . Good thing is , we make the filters in our plant !

We have two completely different air systems going on also . HP plant air and 28 PSI " heated air " 800 degrees . This may be the cause of some of the problems . We have engineers coming in next month to try and diagnose our issues .

Don't pretend any special knowledge on the subject - but the 800 degree air at only 28 PSI can hold a LOT of vapor in suspension. I'd imagine it would be almost impossible to filter (the separators torture the air to try to convert vapor to larger droplets that can be filtered or dropped into the filter bowl).

 

[Larry$]

Getting the water out is one of those things you pay for up front or down the road. An air to air cooler helps but you need additional drying. As air is used it cools from expansion. Cool air holds less moisture than warmer air so you get condensation at point of use if the air hasn't been dried enough. Change desiccant often. It is usually available with a color change ingredient to show when it needs changing. Refrigerated driers cost more up front but don't take as much maintenance. They are better for shops for continuous air use. Big desiccant self regenerating driers are available.

 

[Firstram]

I'm starting to feel inadequate with my puny 5hp compressor.

Shouldn't, if it does what you need, it's perfect. Enjoy your dry air!

 

[rabler]

I've added this to my list of projects. Thanks for the idea!

 

[MtnBiker]

Shouldn't, if it does what you need, it's perfect. Enjoy your dry air!

Thanks for trying...but I won't be truly satisfied until at least 100 HP of compressor power. I feel like 3,500 HP might be overkill for a garage-based side hustle though.

 

[MtnBiker]

Getting the water out is one of those things you pay for up front or down the road. An air to air cooler helps but you need additional drying. As air is used it cools from expansion. Cool air holds less moisture than warmer air so you get condensation at point of use if the air hasn't been dried enough. Change desiccant often. It is usually available with a color change ingredient to show when it needs changing. Refrigerated driers cost more up front but don't take as much maintenance. They are better for shops for continuous air use. Big desiccant self regenerating driers are available.

I hear you - spent some time looking at various commercial solutions just for grins. Big money. As we grow this outfit we'll add capability as needed. For now, we'll be installing a Milton polishing system with a fairly large, for a garage shop anyway, 2 quart desiccant dryer.



I may put an additional Motor Guard filter at point of use. We'll see how things work out with the CNC plasma.

Who knows, maybe we get big enough to buy one of these auto-regenerating desiccant dryers someday:

 

[Firstram]

Thanks for trying...but I won't be truly satisfied until at least 100 HP of compressor power. I feel like 3,500 HP might be overkill for a garage-based side hustle though.

You could set up a small Indoor Skydiving Source as a side side hustle!
When I retire I'll have to downsize my compressor to something home shop sized. 100 amps won't run my 65 amp plasma and start this one.

 

[MtnBiker]

So here is some technical background that most will find boring. But just in case - I've done a little more homework. Consider the following:

• Let's compress 8 cubic feet of air down to 1 cubic foot (about 100 PSI).
• Compression makes a lot of heat which allows air to store a lot more water as vapor.
• Once cooled back to ambient, that compressed air will only hold about 1/8th as much water vapor.
• So 7/8ths of that incoming vapor in the air will have condensed to liquid water (the reason you drain your tank).
• Regardless of whether you have an after-cooler or not, the now ambient temperature air in both scenarios will be at 100% humidity. Really.
• Per the point above - with or without an after-cooler, if ambient temp air comes out of your tank there is an equal amount of water vapor.
• With an after-cooler you'll remove most of the liquid water. That's good - keeps the tank from rusting (and going all JATO in your shop).
• If you leave your tank pressurized, drain it regularly and only use it to run a nail gun, an after-cooler won't buy you much.

However:

• Let's say you don't keep your compressor pressurized all the time. And you fire it up right before you use compressed air.
• Or let's say that you do long runs on a CNC plasma, sand-blaster, paint job, die grinding.
• You'll add or start replacing all that nice cool, but 100% relative humidity air, with very hot, very saturated air that carries about 14X more water vapor at 150 PSI.
• An after-cooler will give you stable outlet temperatures and LOTS less water to filter downstream.
• A downstream coalescing filter / water separator will not get overloaded so quickly sending water through the line.
• If you use them, your desiccant dryer will thank you (and last way longer).
• If you use a refrigerant dryer you'll get much better results.

Industrial applications need after-coolers because the compressors are running all the time. If you are using compressed air with your pump running you should have an after-cooler. If your pump rarely if ever runs when you are using your compressor and you have an automatic tank drain you might not need an after-cooler.

If interested, this is a pretty good deep dive:

 

[MERLIncMan]

I hear you - spent some time looking at various commercial solutions just for grins. Big money. As we grow this outfit we'll add capability as needed. For now, we'll be installing a Milton polishing system with a fairly large, for a garage shop anyway, 2 quart desiccant dryer.

View attachment 376602

I may put an additional Motor Guard filter at point of use. We'll see how things work out with the CNC plasma.

Who knows, maybe we get big enough to buy one of these auto-regenerating desiccant dryers someday:

View attachment 376603

Here ya go brother!

You got me brain doing things, so Google found this little guy.

MDH3-AHE Mini Regenerative Desiccant Dryer, 1.1 SCFM @ 100 PSIG, 115VAC

AVP is a leading provider of compressed air dryers, Laboratory Air Compressors, air compressors, natural gas dehydrators & equipment for removing water vapor from compressed air & gas.

shop.airvacuumprocess.com

Not as neat as a home-built, but if you pay yourself by the hour, it might make sense.

Oh, the plots and the schemes!