"The compressor that we have offered is already a roots blower type which is the most robust type of design for this application. For a continuous operating blower the amount of liquid water entering must be zero or excessive wear and vibration will occur resulting in significant compressor damage within a few months operation. For this application a small amount of water vapour is acceptable (which is possibly corrosive when mixed with some components of the gas) because the internals of the blower are treated with corrosion resistant coating but liquid water must not be present because it causes vibration, wear and local corrosion pitting. When the gas passes through the blower the compression process heats the gas and the temperature rises by about 60 Deg C and more at lower flows. Hence the gas passing down the pipe to the boiler is hot and will slowly cool as the heat is lost through the pipe to atmosphere. The temperature will never get back to atmospheric temperature again though and hence it is extremely unlikely that any moisture will condense in the pipe as you describe. Your concern about moisture condensing on the way from the blower to the boiler is not a problem because the gas is heated in the compressor. It is virtually impossible for any liquid moisture to be formed before the gas reaches the boiler. Even if liquid moisture is present in the gas the amount of heat used to vapourise it is minute compared to the combustion heat in the gas. For example if the gas contains 1% by mass water droplets which is significant the energy required to convert this to steam is 0.1% of the available energy and is insignificant. Hence we do not consider that 1,000 metre of pipe will ether generate any water droplets or lose any available energy from the gas.
We will consider further alternatives to using water bath heater but we do not agree that cooler is a practical option."