Steam Turbine performance with variation in inlet steam pressure 2

[icecool]

Dear All,

I am estimating a future problem while still in erection phase for 60 MW steam turbine. I may need your help to estimate a solution.

Due to some reason my process heater is not able to generate steam at the desired pressure (other parameters are remain same). Therefore I want to know the effect of reduce inlet pressure in the HP Steam turbine output. Th steam parameters are mention below

Steam Turbine is Superheated, Condensing type with Reheater (HP-LP combination)

1. Normal condition
Manufacturer : GE
HP Steam inlet pressure : 98 bar
HP Steam inlet temperature : 365 Degree C
HP Steam Turbine outlet pressure 23 bar
HP Steam Turbine outlet Temperature 220 Degree C

There is 1 extraction of steam from the turbine to HP Heater

2 Revised condition

HP Steam inlet pressure : 75 bar
HP Steam inlet temperature : 365 Degree C

Can somebody suggest the role of pressure in steam turbine. Will steam turbine able to work properly even at low inlet pressure?

 

[icecool]

hermit47,

What is component number? Does it relates to number of stages in a turbine.

Also it seems to me that the pressure lines are parallel to each other in most part of the expansion. That means apart from low pressure region the expansion at different pressure will be same?

 

[hermit47]

I run meanline analysis in AxSTREAM. Here component stands for either rotor or stator.
The expansion is almost the same in both cases excluding last stage (see charts below)

And the reaction of last stage will be negative. It means that rotor works in compressor mode.

All simulation above where performed on sample turbine obtained via preliminary design.
Also it was meanline analysis only.

For more reliable results it is necessary to use actual flow path geometry and streamline analysis. It is much more expensive work.