Turbine Problem 1

[escariote]

Hello everyone.

i need you help regarding turbine test, the problem after we run the turbine (hot condition) about 1 hour, the shaft cannot rotate manually. but during cold condition the shaft is easy to rotate manually.

also if someone can give me reference for commissioning a boiler or share or tips it will be highly appreciated.

thanks in advance..
Escariote.

 

[metengr]

What is the size and manufacturer of this turbine? Typically, there are turbine start-up and shutdown procedures that are provided by the turbine manufacturer to ensure the rotor heats and cools uniformly before and after operation. Are you following turbine shutdown procedures after operation? Normally, the turbine is placed on a turning gear to avoid thermal bowing.

 

[racookpe1978]

What are you doing with lube oil flow and temperature?

This is wrong - dead wrong - and you need to check with your turbine sales representative (and the turbine installation company rep)immediately.

 

[escariote]

@metengr and racookpe1978

thank you for your comments. after thorough investigation and several testing, we found out that the exhaust piping during hot condition pushes the turbine so we need to install a new support to reinforce the piping.

escariote

 

[dougarthur42]

We had the same issue with our unit. Our turbine is 110 Mw unit, it run at 1350 psi and 925* F temp. Our problem was when we took the unit off it would turn for an hour then bind up and stop we couldn't get it going at all. even our turning gear would not move it. After 3 or 4 shut downs we changed the way we shut down, We now take the unit from full load to minimum load 3 to 5 megs. We run it there for about 1 hour. then we trip the unit and turn it with steam at approx 1000 rpm for 45 minutes. This work with us and our casing and flange metal temps cool more evenly and we don't have any trouble. Next we trip the unit isolate the steam an put it on turning gear at 55 rpm until the rest of the cooldown occurs. From full load to turning gear in about 3 1/2 to 4 hours not really that bad overall. also we keep the gland steam and vacuum on the unit until we secure the steam, this keeps cold air from being drawn across the shaft. hope it helps Doug

 

[rmw]

Nice explaination Doug. A star for you.

rmw

 

[gr2vessels]

I'm not a kill joy, but I wonder what's going to happen after an emergency trip...
Cheers,
gr2vessels

 

[rmw]

The OP's problem and probably lots more bad stuff.

rmw

 

[chief]

A flexible banjo section is required on the exhaust to absorb thermal expansion and misalignment piping issues.

Offshore Engineering&Design