Air and non-condensable gases are one of the major problems in a steam system.   Both can cause production problems for a steam system’s operation and performance.   For example, the thermal conductivity of air is 0.000049, compared with 0.002 for water, 0.20 for iron, and 0.96 for copper.

 Not removing air and non-condensable gases from the steam system can reduce heat transfer efficiencies by 21 % or more depending on the air concentration in the steam system. Because air is one of the greatest insulators, a major steam operation objective is elimination of air from a steam system.

 Adding to the problem is the fact that steam systems are typically not designed to eliminate air at startup or during operation.

http://www.swagelokenergy.com/download/Best%20Practices_No.28LR.pdf

We have a process heating system and we continue to have steam coil failures. The failures are always located in the bottom header assembly. The units are 40,000 scfm and using 165 psig steam pressure to the steam coils. We have tried several different steam traps, based on information from the steam trap supplier – but continue to have coil failures. We have received quotes on “better materials” from the steam coil supplier, but the improved material selection has not stop the coil failures. What are some of the causes for steam coil failure? How do I calculate the real cost of constant coil replacement?