Purging Carbon Dioxide from cooling system


Thread Starter



i want to know after purging of Hydrogen, why there is necessary to purge out Carbon-dioxide from generator.


Carbon dioxide is used as an intermediate inert gas to displace air and hydrogen from the generator in order to avoid air-hydrogen mixture, as hydrogen is very explosive and flame is supported within a wide range of concentration from 5% to 75%.

The purging procedure, after a maintenance for example, is to introduce carbon dioxide to displace the air, then hydrogen is introduced to displace the carbon dioxide.

Purging carbon dioxide is necessary as it has higher density and lower thermal conductivity than hydrogen. So generator cannot be placed into service until 95% hydrogen in carbon dioxide discharge is obtained.


You have not defined the conditions of purging. If someone is to be "entering" or accessing areas of the generator that would have CO2 it would be best to purge the CO2.
I know it's an old thread but i was wondering about this same thing myself. Assuming that there will be absolutely no entering into the generator, would there be an issue of having CO2 instead of air inside the generator for long periods of time (1 week)?