Hi All,

We have 3 units SGT6-3000E Siemens Gas Turbine. The Lube Oil Header Temperature Trip is 155 Deg F. We plan to increase the setting since operate other gas turbine and

I want to have opinion from others users about:

1. What are the consideration for determining the Lube Oil Header Temperature Trip?

2. What is the other Gas Turbine Lube Oil Header Temperature Trip setting for the same or high size turbine? (100 MW Operating Load ~ 120 MW Rating @ ISO Condition)

Best Regards;
Sati

 

Hi,

Kindly follow the VENDOR specification document in steady of some body opinion. It is always better follow or adopt data sheet.

best regards
saradhi

 

I reckon you are pretty crazy thinking about changing this setting without consulting the manufacturer. This setting is protecting all the devices using Lube Oil particularly the bearings. Why do you want to increase it anyway? Are you running near the trip point, if you are, that is the problem you need to address.

 

> I reckon you are pretty crazy thinking about changing this setting without consulting the manufacturer. This setting is
> protecting all the devices using Lube Oil particularly the bearings. Why do you want to increase it anyway? Are you
> running near the trip point, if you are, that is the problem you need to address.

The reasons are:

1. Not all gas turbine has this kind of trip level, they rely on the bearing metal temperature trip point only.

2. Some gas turbine that we know (<75 MW) has higher lube oil header trip setting, like GE Frame 6B or 7EA which is around 175 Deg F.

3. Yes correct, we are running near the limit and recently the ambient temperature is quit high in the power plant.

We are consulting to OEM but no feedback yet.

I just want to know what are the other user setting and consideration during determining the trip setting.

Cheers;
Sati

 

rkysati,

glenmoranjie's 1000% right--the real problem is why is the L.O. Header temp so high?

The trip setpoint is a function of L.O. vapour flashpoint temperature which is also affected by the expected pressures in the bearing cavities. A fire or explosion can result if the L.O. vapours ignite in the bearing cavities--and that would be extremely undesirable and difficult to extinguish!

Solve the cause of the excessive high L.O. Header temp--and protect the turbine. Allowing the L.O. Header temp to keep increasing runs a very real risk of catastrophic damage to the turbine, or worse, personnel in the area when a L.O. fire erupts might be hurt--or worse.

Turbine trip set points aren't selected willy-billy with little or no foundation. Tripping turbines is very hard on the hot gas path components because of the thermal stresses caused when flame is lost very suddenly in the combustor(s) and as the turbine coasts down while hot.

I'm willing to wager the cause of the high L.O. Header temp is known--but it requires a lengthy and or costly shutdown to resolve--and management doesn't want to shut the unit down at this time to fix the cause of the excessive L.O. Header temp.

Do as rvsaradhi and glenmoranjie have suggested--follow the OEM specifications. Or be prepared to suffer the consequences of not doing so.

 

For GE D11 steam turbine and Alstom like that we haven't any protection for lube oil header temp.