How Much Condensate Water for a Given SCFM of Compressed Air

With a little bit more information this calculator will calculate for you:

Can the intake not be located somewhere else? That's a lot of water, perhaps consider a move of the compressor itself? That humid an environ can be unfriendly on equipment.

I don't care how many scfm you are making, condensate removal is absolutely necessary. Water in the airlines will destroy much of your air powered equipment.

I know this from experience, when our air dryer went down, Management thought we could hold off on a new one. I nickeled and dimed them to death with failed MAC valves, air motors, air brakes, cylinders, defective parts from water contaminating paint guns, etc.

I won, and got an entire new air system from Kaeser, with 2 new compressors, air drier, condensate filters and removal valves, plus a new tank and all new piping because old tank and piping could not be used from the corrosion on the inside. There is a lot of piping in a 50,000 square foot coating facility.

New dryer at the time in went down - $15k

Cost of equipment replaced because of water contamination over a 2 year period - $25k to 35k.

Cost of complete new compressed air system with piping and tanks - $220k

A lot of useful replies, especially about the economic benefits of installing a dryer.

Nobody in their right mind runs a modern compressed system without a dryer.

I say this because over the years manufacturers of products using compressed air to function have relied on 'dry' air to work - often to the extent of using 'wet' air as grounds for invalidating their warranties.

No complex arguments are needed. "Premature failure of our products? Yes!" - "Have you got a dryer?" - "No! - well tough,not our problem."

Anyway back to answer you question about the quantity of water it would help to look at the volume off air sucked in (the volume at atmospheric pressure). Where in your case SCFM means Standard Cu Ft per Minute. The 'standard' refers to atmospheric volume, and 3200 cu.ft should be used in calculations.

All you need is a chart or graph giving saturated water vapour content at various temperatures. For the purpose of keeping it within the realms of mental arithmetic using 25C as the atmospheric temperature it will be 23g/m3. Convert cu.ft to m3 by dividing by 35. that is 92m3. Now multiply both = 2103 grams - and that is 2.1kg per minute sucked into your system.

Now look at the pressure. At 110 psig the volume of the atmospheric air will have been reduced by a factor of 8.5 when it is in the system.

Which comes from the pressure ratio. ie. (110 + 14.7)/(14.7)=8.5. Your air volume is now 10.8 m3. Now the interesting bit - the air volume has reduced but the 'grams', not reacting to pressure, remain exactly the same, ie. 2.1kg in all - where in theory if spread evenly throughout the air would be 195g/m3.

Now because the ambient air is 25C, that is the temperature of your system to which the compressed air will cool to, and when it does the final maximum water the air at any pressure at 25C is still the same = 23g/m3 - and this figure can only be achieved when at 110 psig by 172 g/m3 condensing to liquid.

The problem is the air cools to ambient through every inch of the pipework and the condensate appears everywhere. Any equipment using compressed air will cool as air expands rapidly so further condensation occurs.

A fridge dryer will create a pressure dewpoint below ambient. The condensate drops out at one point, is separated and dumped - the warms up above dewpoint and remains dry as it passes through the system.

Keep to basics when explaining it to 'management' they will not appreciate being blinded with science - as is the complex subject of water vapour in air - the met office with experts and £millions of computers still get it wrong.