Hi All,

We are considering buying dyeing machines kiers for batch dyeing cotton/synthetic made fabrics. We have two options both are pressurised type vessels which can go upto 135 C which is a requirement for polyester dyeing. But one machine has an additional option that in it after 85C if you want to raise the temperature it seals the machine and takes in compressed air @ 2.5 to 3 bar pressure.

This machine manufacturer claims that in this way if you raise the temperature to 135C the boiling point is increased and you save a lot of steam (heating is done indirectly through a shell and tube SS316L heat exchanger using steam).

Can someone give the calculations for how much steam would be saved in the machine that fills itself with compressed air as compared to the other machine in which the machine is sealed but no compressed air is filled in if we have 10 KG water inside the vessel and we want to raise temperature to 135 c from 30C.

 

I would think that any manufacturer making such a claim would be glad to show you his calcs proving his point.

 

I presume the additional cost for the compressed air option would be minimal, so worth a shot. Too many unknowns to answer your question, including size of vessel. This might answer some of your questions:
https://thundersaidenergy.com/downloads/energy-needed-to-produce-steam-enthalpy-and-entropy-data/

 

In most drum rollers, you must constantly drain off all condensate to avoid mechanical intability of sloshing liquids.
Now you are faced with the heat content of compressed air, versus that of steam.

Typically, the last thing you need is air mixed steam/condensate.