Wheel space high temperature at IGV min position


Thread Starter


Dear all,

My Gas turbine is MS 5001PA and has a problem. It is faced with aft 2nd high wheel space temperature and 24 hours to shutdown at 11MW. IGV is still in minimum position 46 degree.

Is there any people melt this situation?



Bob Johnston

Check your IGV control, your IGVs shouldn't be at 46 Deg. at 11Mw. If you are not using IGV Temp. control, your IGVs should be fully open. For sure that is why your W/space temps. are high
Thanks for your comments.

I checked IGV position already, Its position is 46 degree. Our machine uses IGV temperature control. So, When we increase load about 14MW IGV open at 50 degree, then Wheelspace temperature recover normal temperature.

So I think that IGV open so small. It is the cause of high wheelspace temperature. Could I change Minimum position IGV to 50 degrees? Thanks.
I have two GE MS5001 gas turbine. our Machine minimum IGV opening is restricted at 56 degree, at that opening, 09.5 Mw power load, exhaust temp remained at about 410-430 degree C, but now we want to increase our gas turbine temp up to 460C by decreasing IGV opening to 50%. now my querry is: your IGV opening is 46~50degree, do you have Inlet bleed heating system for your gas turbine to protect the compressor from surging.. plz brief it you have IBH or with out IBH you have so low value of IGV. & also tell the exhaust temp at 50 degree & 14 MW.

actually I was surprised when I read posted text MS5oo1 is being operated with IGVs opening 48~50% now my next question related to the above posted was that they have the IBH system with their gas turbine or not. as I contacted with my vendor, his suggestive text was without inlet bleed heating system gas turbine IGVs could not be reduced further, but it can be reduced to even 42 degree (min opening) if you installed IGV system.

So I want to ask that they have the IBH system or anti surge protection system with their gas turbine whose IGVs are at 50 degree , if not then either vendor has recommended this min opening or they did their self.

IBH (Inlet Bleed Heat) is not generally used with machines that do not have DLN combustors. Or, IBH is used primarily with machines that have DLN combustors. If IBH is used on machines with conventional combustors it's generally used to provide inlet air heating in very cold ambients to prevent the formation of ice on the IGVs and first stages of the axial compressor. And that's generally only done at Base Load with the IGVs fully open. And, there is a performance decrease when IBH is used for inlet air heating.

Unfortunately, we don't know if the machines in this thread have DLN combustors, or if they have IBH systems. And, when IBH is active at low loads, there is a performance/efficiency decrease also.

I would suggest that if you went to the expense of adding IBH in order to increase exhaust temperature to increase steam temperature production at low gas turbine loads that you would find the decrease in efficiency (poor heat rate) would increase the cost of the steam above an economical level. In other words, the cost would outweigh the benefits.

If you are operating your turbine at low loads but need higher steam temperature or steam flows, then something has changed with regards to the original intent/usage of the machine or it's being operated in a manner different from that for which it was intended.

I can't recall if we've discussed auxiliary "duct" burners in the exhaust which could be used to increase steam temperature/flow, but that also comes at a cost.

Operating a gas turbine at low load and requiring high steam temperature flows from the exhaust is placing the two conditions at odds with each other. Operating a gas turbine low load with IGVs closed (as they are in combined cycle mode) is already sacrificing some efficiency to maximize steam temperature/flow, and you want to sacrifice even more efficiency. You might achieve the steam temperature/flow you need at low gas turbine loads, but some day some bean counter is going to raise a huge red flag and then you're going to be right back where you are now: trying to figure out how to get what you need, only this time without bankrupting the company with ridiculous capital expenditures or high fuel costs.

Something is really amiss here. I suggest you work with an engineering firm to understand your needs and what might be possible, both from a technical perspective and from a financial perspective (short-term and long-term).