High Pressure Cylinder Compressor Walls Repair

[HVoilF]

Dear SEF members,
our costumer needs to repair a 3Rd stage natural high pressure cylinder compressor working in the following conditions:

Inlet gas pressure : 1200 to 1500PSI
Discharge pressure: 2300PSI
Compressor RPM : 1200 Max gas temperature: 185ºF
Cylinder Diameter : 7,25"
Compressed Gas: natural gas
Piston Rings material : Teflon

We have been repairing the compressor cylinder walls using an arc spray high carbon steel coating,ground and honed . After few hours of operation was found that the piston rings were damaged by premature wear due the porosity of the arc coating of the cylinder surface.
We guess if the correct coating for this application would be a Plasma sprayed ground and honed coating. If so could anybody suggest the correct coating procedure and the spraying techniques as:
Required air extraction flow to avoid oxide entrapment into the coating.
Coating suggested thickness
Coating material friendly to the Teflon piston rings?
Required surface finish

Any technical suggestion is welcomed. Does anybody have experience in similar applications? Is the thermal spraying technology well suited for application like the showed in this post?

   

[Gordon]

Hi HVoilF

Coating material friendly to the Teflon piston rings?

Could you expand on this part? Teflon is extremely soft by itself with poor wear resistance.

[HVoilF]

Thanks Gordon. The fact is that D/R manufactures this third stage high pressure cylinders with "glass Teflon" I don't really know which material is but for sure is harder than pure Teflon..I am trying to get more info about this material,it hardness and it properties. Do you know if somebody repair high pressure cylinders with some thermal spray procedure?