Steam Turbine Vacuum System

[Emkel]

Hello, im graduate trainee and i have a question about Steam Turbine Vacuum system.

This is our vacuum interlocks
Jet Water Pump press : 5 - 6 bar
Vacuum Normal : (-0.86) - (-0.91) bar
Vacuum alarm water pump : <-0.75 bar
Turbin trip : -0.61 bar


What might make the vacuum system not work normally and cause a turbine trip?

 

[ScottyUK]

Leaks.
Gland steam problems
Poor condenser performance (fouling, blockages)
Inadequate cooling water supply (too warm, low flow)

 

[crshears]

Hello Emkel,

"Jet Water Pump" - ? - suggests a contact or "jet" condenser, a technology that to the the best of my knowledge is rarely encountered nowadays. Can you share more information about the application?

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[ScottyUK]

crshears -

I read that as a venturi-type ejector using water rather than steam as the motive power. Might be wrong - would be a strange choice if steam is available.

 

[EdStainless]

Is this the vacuum system for the condenser?
I have seen water jet eductors used on small units before.

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P.E. Metallurgy, Plymouth Tube

 

[Emkel]

Sorry i just read your reply.

Thx before for your answer, yeah the ejector use water. This is vacuum system for condenser.

This is the vacuum system :

What major problems that can disturb vacuum system?

 

[EdStainless]

When trouble shooting one of these the first step is to check water temp, pressure, and flow. If not then fix the water system. These also look to have cooling water jackets on them, that water needs to be checked also for flow and temp.
If those are all to spec then you blank off the inlet of the eductor and see if it will pull the correct vacuum. If not then replace the eductor, there could be internal erosion that has damaged it.
If those both work fine then you need to look for leaks, and look everywhere. Start with the lines back to the condenser, then everywhere else, coupling between the turbines and condenser neck, condenser shell, turbine housing, every line that penetrates the condenser shell needs to be traced back also.

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P.E. Metallurgy, Plymouth Tube