Just wanting a little guidance on filter sizing for an upcoming installation for a combustion test cell.
About a year ago I was asked to procure a vortex oil/water separator for a pair of reciprocating compressors (Worthington BDC). To size the separator, I simply took the stated ICFM of both compressors (~9500cfm combined) and ordered according to that figure. The discharge pressure of both recips is 300psi max. I obtained a 10,000cfm unit rated at 300psi. Was my methodology correct, or should I have taken something else into account? It seems to be working well, except for some float drains that are going to be replaced with pneumatically operated full-port ball valve style autodrains to correct a plugging issue with the current small-orifice (5/32") drains.
My current issue is that I have been asked to size an appropriate coalescing filter for a new installation in another test cell. One stream of air is coming from the two recips, while a second stream will be coming from a pair of Atlas Copco HM7 centrifugals. The recips flow through a dedicated filter rated for 10,000cfm in the basement, so that part is taken care of. The problem lies with the centrifugals. They are rated at 7pps each. I need to convert this to a CFM figure to properly size out a new filter. Here's where I always get confused.
I take the weight of air at .0807 lbs/cuft. Each compressor is good for 7pps, so 7 lbs/sec / .0807lbs/cuft = 86 cuft/sec = 5204cfm X 2 compressors = 10,408cfm. I realize the air will not be "standard" weight, as of course it will have moisture in it, but it works well enough for my needs.
Considering one of these centrifugals @ 2500hp is already equal to both recips at 1250hp apiece, it seems like I either grossly oversized the vortex separator, or I am underestimating the flow from 5000hp worth of centrifugals. Where am I making my mistake?
Thank you for any guidance you can offer.