Why Is Hydrogen Purity Important For Cooling Generators?

Why is hydrogen purity important for cooling generators?

Purity is important primarily for safety reasons. Purity of hydrogen must be kept above the 75% UFL (upper flammability limit). Most generators have alarms set at levels above 90%, and if purity drops below 88%, an automatic trip and purge occurs.

Purity of hydrogen also has an impact on effectiveness. Hydrogen is 14 times less dense than air. When the hydrogen purity in a power generator casing is less than 99%, air makes up the majority of the pollutant.

The hydrogen gas produced is 47% denser for every 1% of purity below 99% (the realistic feasible / maintainable purity in a power generator).

Viscosity, which naturally has an impact on friction, is directly influenced by density. Windage loss is a problem that gets worse with increased friction. Windage loss is the energy that could have been used to generate electricity that is instead converted into heat by the friction of the revolving rotor.

This windage loss per percent purity can range from 70 to 400 kW per every percent purity below 99, depending on the power generator's capacity and the generator OEM's design specifications.

Depending on generator capacity, this translates to somewhere between 600 and 3,650 MWhr/year for every percent purity kept below 99%. In power plants, hydrogen purity is typically between 94 and 99%.