for the proposed 800 MW Combined Cycle Power Plant ...

CO 2 Capture Study
For 800 MW Power Plant – Tjeldbergodden
1. The alternative of using an auxiliary boiler to provide the steam for the
CO2 capture plant has been demonstrated to be of lesser thermal
efficiency
If the rules of integration are to be followed then the alternatives are:
2. Install the optimum steam turbine for the capture case and accept the
inefficiency resulting while the capture plant is not present.
3. Install the optimum steam turbine for the capture case and add a small
steam turbine to accept the steam which will be used by the capture plant
when it is eventually commissioned
4. Install the optimum steam turbine for the non-capture case and accept the
inefficiency resulting after the capture plant is commissioned and the
plant will be configured as shown below
HP Steam
Source
Reheat
Coils
IP Steam
Source
LP Steam
Source
Condenser
Steam to CO 2
capture plant
Steam Circuit for CCGT Power Plant with steam extraction for CO 2
capture plant
GT-Master versions of the abated and non-abated cases were made and
used to demonstrate each case in the off design form. The net thermal
efficiencies obtained are:
With Extract Without Extract
Small LP Turbine (Abated case) 51.71% 55.31%
Large LP Turbine (Non-abated case) 51.50% 56.63%
In reality these results show so little difference between either configuration of
turbine that there is no point in considering the addition of a small temporary
turbine (alternative 3 above). Alternative 4 will give a marginally greater
output until the Carbon dioxide capture plant is commissioned but the capital
cost of the turbine is likely to be higher. It is suggested that options 2 & 4
should be developed during detailed design with a turbine supplier when the
costs can be developed in greater detail and when the minor performance
differences can be quantified with assurance.
CB2005-0022_Final Report.Doc