Steam Turbine efficiency calculation VIA HYSYS
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Asim shahbaz
- Posts: 2
- Joined: 24 Mar 2010, 12:59
- Area of interest: Chemical Engineering
Steam Turbine efficiency calculation VIA HYSYS
How can we calculate steam turbine efficiency through HYSYS? P1, T1, Q1,P2,T2 are known.
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Imran.Idris
- Core Member
- Posts: 59
- Joined: 16 Mar 2010, 04:22
- Area of interest: Chemical Engineering
Re: Steam Turbine efficiency calculation VIA HYSYS
Dear Shehbaz,
Select turbine from Hysys tool bar, provide flow, and any of the two inlet conditions; similarly provide any of the two outlet conditions (temperature pressure or temperature enthalpy or pressure enthalpy etc). Delete default efficiency used by Hysys.
Getting the same efficiency using Steam Tables...
For an ideal steam turbine, entropy remains the same both at inlet and outlet. At inlet conditions (temperature and pressure), you need to get the following properties of steam:
1. Enthalpy
2. Entropy
For a given outlet pressure which is desired in normal plant operation, for the same entropy as at the inlet, you will get outlet temperature and enthalpy if the turbine was going to behave as an ideal.
Work done in ideal condition will be change in enthalpy at inlet & outlet conditions.
This is called ideal work.
For actual conditions, when we know the temperature and pressure at the outlet of turbine, you can get enthalpy from the steam tables. In that case actual work done will be the difference of enthalpy at outlet and inlet conditions.
And finally the ratio of actual work to ideal is Turbine Efficiency.
For example,
say at T1 and P1 the entropy of the system is S1 and enthalpy is H1
at ideal conditions, S1 = S2
for ideal outlet conditions, at P2 and S1, enthalpy will be Hi (H ideal)
Ideal work would be H1 - Hi
For actual conditions, at P2 and T2 calculate H2 from steam tables
and actual work would be H1 - H2
Efficiency = (H1 - H2) / (H1 - Hi) * 100
Select turbine from Hysys tool bar, provide flow, and any of the two inlet conditions; similarly provide any of the two outlet conditions (temperature pressure or temperature enthalpy or pressure enthalpy etc). Delete default efficiency used by Hysys.
Getting the same efficiency using Steam Tables...
For an ideal steam turbine, entropy remains the same both at inlet and outlet. At inlet conditions (temperature and pressure), you need to get the following properties of steam:
1. Enthalpy
2. Entropy
For a given outlet pressure which is desired in normal plant operation, for the same entropy as at the inlet, you will get outlet temperature and enthalpy if the turbine was going to behave as an ideal.
Work done in ideal condition will be change in enthalpy at inlet & outlet conditions.
This is called ideal work.
For actual conditions, when we know the temperature and pressure at the outlet of turbine, you can get enthalpy from the steam tables. In that case actual work done will be the difference of enthalpy at outlet and inlet conditions.
And finally the ratio of actual work to ideal is Turbine Efficiency.
For example,
say at T1 and P1 the entropy of the system is S1 and enthalpy is H1
at ideal conditions, S1 = S2
for ideal outlet conditions, at P2 and S1, enthalpy will be Hi (H ideal)
Ideal work would be H1 - Hi
For actual conditions, at P2 and T2 calculate H2 from steam tables
and actual work would be H1 - H2
Efficiency = (H1 - H2) / (H1 - Hi) * 100