why is hydrogen gas preferentially used in cooling a steam turbine generator
Hussein
Where is hydrogen being used as cooling gas for steam turbine generators?
I am curious to know, based on the information I posted previously it would not appear to be a good candidate for a cooling gas.
What am I missing?
Niel
Follow up to my post of yesterday concerning Hydrogen as a Coolant for Steam Turbine Generators.
General Electric [1] has been building Hydrogen Cooled Gas since at least 2005 [2] (so they are relatively new).
It appears that with the proper selection of materials and design of the seals most of the challenges using Hydrogen Gas as a coolant have been resolved, so they would be viable systems.
Niel
You can read the information at
http://en.wikipedia.org/wiki/Hydrogen#Applications
and I stated that the generator room is sealed so only hydrogen is present there, which eliminate any danger of explosions (no oxygen to burn with).
I worked at a dual purpose desalination plant previously & they also were using hydrogen as coolant in the steam turbine generator.
Sish:
Thank you for the link, in application as described where hydrogen is used as a conductor (highest conductivity) and not simply as a coolant I can see how and why it is used.
Large steam turbines use gas bearing to support the various rotating components away from each other and reduce friction.
As a coolant that is used to remove heat, it would still appear to be less than an ideal medium for the reasons that I noted in my original post. It will take large amounts of hydrogen to remove the heat. Maybe in conjunction with the excellent heat conductivity, it does work out.
I will take this further and ask some questions of some Power Plant Engineers I know.
Niel
All:
I deleted my first post because some of the assumptions where incorrect. Hydrogen has been used as a coolant in large steam turbine generators for more than 40 years (Thank you Ed Coleman, a power plant engineer I know).
My concerns about flammability issues are valid. All large power plants are design with this issue in mind. Most of the systems in the turbine gallery are designed as explosion proof.
The hydrogen does leak out of the turbines though all the rotating seals. They facilities all have big tanks of hydrogen gas and keep pumping the necessary hydrogen into the system to maintain pressure.
Niel
The specific heat capacity of hydrogen is very high compared to other gases, also hydrogen is available through more convenient methods than other gases, and it should be noted that the generator room must be sealed so that no air will infiltrate the room causing critical problems obviously. Also as a sealing gas between the rotor winding and the lube oil of the turbine -rotor coupling shaft.
