Chemical filter consideration for instrument air compressor

[Wkcoo]

Does anybody have experience in design consideration when specifying chemical filter (for h2S,SO2 removal) is required for integral gear instrument air compressor?

Have a integral gear instrument air compressor with 17-4PH impellers (3-stage with intercoolers) which takes suction from atmosphere. Trying to understand if there is any guidance on these contaminant limits for satisfactory compressor life, and whether the chemical filter is specified to reduce fouling / deposits on rotor which can cause vibration due to unbalance or to avoid corrosion on the casing internals.

New machines seem to be equipped with chemical filter by default.

Any input is appreciated!

 

[compguy22]

In general a reference could possibly be to look at NACE MR0175 as far as H2S is concerned. I do not know about SO2.
Basically depending on whether the service is Sour and its severity, the current material selection of the rotating parts in contact with process medium may become limited and 17-4 might become inadequate for impellers (especially the 1st inlet). The severity is based on Pp of H2S and the relative humidity, which again depends on the quantity of H2S in ppm, water content and process conditions at operation and stand still, if that is applicable. I guess from there, the concept of filtration would have amongst other things the objective to limit the quantity of H2S ppm flowing through the machine. As regards the particles carry over acceptance, this is dictated by OEM in particular in view of criterion on erosion.