Hi guys.....I am working with GE frame 6 machine.

I want to understand that in gas turbine how CPD and FSR relates to TEMPERATURE CONTROL as i am not getting it. As i read the constant firing temp curve btw exhaust temp and FSR similarly between emp and CPD.

Please reply..........

Please explain CPD bias and FSR bias.

 

The exhaust temperature control line (exhaust temperature vs. compressor discharge pressure) is a horizontal line (isothermal limit which protects the exhaust system) at lower compressor discharge pressure. At some point, the line slopes down so that the exhaust temperature limit decreases as compressor discharge pressure increases - this part is the constant firing temperature line, which protects the first stage nozzles and buckets.

For a fixed speed turbine with the IGV's full open (i.e., generator drive without waste heat recovery), you can approximate CPD as a function of FSR, and thereby eliminate the need for measuring compressor discharge pressure.

Generally, if there are transmitters for CPD (I think all GE gas turbines with current combustion systems have CPD transmitters), then FSR bias is not needed. But back in the good old days, before anyone cared about NOx, FSR bias was a cost effective way to get the job done. (Back on Mark I and Mark II, it was called VCE bias, for those of you whose hair is as gray as mine.)

 

Dear Sir,

Welcome to Control dot com....

There has been a huge GOOOOOOOOOOOD talk on this subject.

Use the GOOOOOOOOOOD feature of control dot com i.e. SEARCH

With Regards

 

Dear Sir,

what is the differance between cpd and the unit being in peek? and do both cpd and peek put the same wear on the turbine?

 

CPD is used for BOTH Base Load and Peak Load temperature control. Peak Load occurs at a slightly higher firing temperature and CPD than Base Load. The exhaust temperature control "curves" for both Base Load and Peak Load represent constant firing temperatures (the temperature of the hot gases leaving the first stage turbine nozzles--not the exhaust temperature, and not the flame temperature).

Gas turbines are designed for optimal operation at Base Load (CPD-biased exhaust temperature control)--meaning that the hot gas path parts (fuel nozzles; combustion liners; transition pieces; turbine nozzles and -buckets; exhaust components) will last reasonably long at that firing temperature.

Peak Load occurs at a higher firing temperature, therefore the firing temperature the turbine is subjected to is hotter--and the hot gas path parts life is degraded, sometimes significantly. This means that maintenance outages will have to be scheduled sooner, and that prolonged operation at Peak Load will result in much more wear on hot gas path components.

More power is produced at Peak Load, but it comes at a price--and not just fuel cost. Peak Load is intended to be a occasional, "emergency" operating condition. If turbines are operated for very long at Peak Load without the additional maintenance outages it is very likely that catastrophic damage will occur.

Hope this helps!