plating, anodizing, & finishing Q&As since 1989
Air Tubes Failure in 2nd Stage Air Compressor
I have a serious problem in air compressor particularly in 2nd stage intercooler, the intercooler is shell and tube type, the air is passing in the tube bundles whereas is the water used for cooling flows in shell side. Actually our compressor has three stages with coolers, we are facing the tube failures in the 2nd stage only, we have inspected and plugged 10 tubes out of 130 tubes and because of the that pluggings in the tubes our air temperature outlet reached to a higher worrisome limit !
We have investigated the problem and we are sure that our air surrounding quality is unhealthy, it contains some acidic contaminants, we make analysis with using copper coupon fixed in the air suction, we had analyzed and found un health limit for H2S, sulfide and chlorines exist with the air. We have six air compressor units three in utility I and more three unit in utility II,these phenomena is common in the six units specifically and only in the 2nd stage intercooler, BUT BUT WHY, the answer is simply that intercooler in 2nd stage is higher in cooling duty than the other in 1st or 3rd stage, so any acidic contaminant exist in air,it can easily get condensed with the moisture and can attack the tubes. Our engineering stuff came to a conclusion that we need to upgrade the tube bundles to another material can resist the attack and avoid corrosion. Our tubes bundles made of Copper, Again we have plugged 10 tubes in one compressor. the question is what is best material can be selected to avoid any tubes failure because of air quality? Also I need your experience to tell me more about this phenomena, we are believing that we are working in very unhealthy environment?
NOTES: don't ask about the water quality because we have a huge amount of coolers exist in our complex working very well with using that cooling water with our and recorded problem....
SABIC-IBNRUSHD - YANBU INDUSTRIAL CITY, WESTERN REGION, K. SAUDI ARABIA
It is my understanding that with an atmosphere such as yours that this is a fairly common, not only in your coolers, but also downstream of the compressor where moisture can condense. From what I understand, as the moisture in the air condenses, it mixes with the contaminants you mentioned and forms an acid. Moisture can condense where ever the dewpoint of the air is lower than the surrounding environment. So you can expect that the pipe downstream of the compressor(s) to degrade. You ought to UT the piping between the compressor discharge and the air dryer (if you have one).William M Eister
Duke Energy - Seneca, South Carolina