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I'm processing hydrocraker and my question is about steam turbine vibration hunting.
This is Recycle gas compressor turbine and its driving force is HP Steam.
I've noticed that HP steam Temp. & Press. was little changed after discovered the problem and controlled them.
But vibration hunting has still been occurring and I'm looking for another source of hunting.
Could you please advise about this if anything you have a similar experience or knowledge?
 
Answers
28/12/2011 A: Bruce Carr, Suncor Inc, matukaze1@hotmail.com
What type of governor system is on the turbine? A lot of times excessive tolerances in the governor linkage can lead to hunting. Most steam throttling valves operate within a small range some only have 5/8" travel from fully open to closed. Hunting will occur if the process conditions are constantly changing which is most likely in your system. This can sometimes be eliminated (short term solution) by throttling in in on the inlet block valve forcing the governor to operate within a different range. (this is only a short term solution and more of a troubleshooting technique as it will soon cut the valve assuming it is a gate type valve which will make isolating the turbine difficult) if it works the trim of the throttling valve requires to be redesigned. If the turbine is equipped with auxiliary steam nozzles, try closing one off, again this will change the operating range of the governor.