Steam Turbine Operating Cost Calculation
Steam Turbine Operating Cost Calculation
(OP)
I'm working on some cost justifications and looking at the existing operating costs of some seal oil pumps. One pump is motor driven, one turbine driven. What do I need to calculate the operating cost of the turbine?
What I have:
Turbine HP
Inlet / exhaust conditions
Cost of steam ($/1000lb)
Steam Flow
What I have:
Turbine HP
Inlet / exhaust conditions
Cost of steam ($/1000lb)
Steam Flow





RE: Steam Turbine Operating Cost Calculation
A typical turbine with 600 psi @ 700 F inlet, exhausing into a 40 psi header will have superheated steam at about 440 F (based on 45% isentropic effiency). The enthalpy goes from 274 btu/lb to 179btu/lb (net 95btu/lb). If the exit steam is used as a heat source and condensed and cooled to 250F, an additional 1035 btu/lb is removed. So in reality, the turbine only used 95/1130 or 8.4% of the steams energy which means, only 8.5% of the value in the first paragraph.
Now, if you have a condensing steam turbine, you'll need to go through the same calculations and you can get 30% or more of the energy is used.
RE: Steam Turbine Operating Cost Calculation
As for decasto's example, the enthalpy of 615 psia (600 psig), 700 deg-F steam is approximately 1350 Btu/lb. Assuming the same efficiency of 45% and 55 psia (40 psig) exhaust pressure, the exhaust enthalpy is about 1249 Btu/lb.
RE: Steam Turbine Operating Cost Calculation
Give us some more information.
rmw