Many industrial processes need a supply of hydrogen gas, and users who need very high purity and large quantity may decide to make their own gas, rather than buying from a gas manufacturer. There are two common ways of producing the gas:
1. Electrolysis. Air is broken down by electrolysis, and the resulting hydrogen is used by the application. There is a risk of mercury contamination, which will damage the Shaw sensor.
2. Palladium diffusion. Methanol is the raw material in this case - the hydrogen being separated at high temperature through a diffusion process. On start-up of a new plant there can be severe contamination of the gas with many impurities, including ammonia, although this process is usually sold because of the high purity hydrogen it produces when working properly.
Some years ago someone had a good idea: use hydrogen instead of air to cool an electrical generator and, because its a better conductor of heat, the power output of the generator can be increased without making it any bigger! This is now almost standard practice with the stator being water cooled, and the rotor being hydrogen cooled. The gas needs to be dry because of the high voltages and it can also act as a leak detector for the water cooled sections. (N.B. the system must be intrinsically safe. We have a specially designed sample system which is part of the recirculation system, and monitors the inlet and outlet of the dryer.) Usual moisture: <-60°C.