Power Generation/Gas Turbine Power/Part2

Figure 2:A diagram of IGCC (integrated gasification combined cycle) power plant ( Click on image to view full size image )

Gas turbine in a Combined cycle: Because Gas turbine stations are expensive to operate on their own, they are usually constructed in a Combined cycle configuration together with Steam Power station. Figure 2 is a schematic diagram to illustrate the Combined cycle configuration. Notice that the overall efficiency of this Combined cycle configuration station has a much better efficiency compared to a Steam Power station with ≈ 30% efficiency. Pros & Cons: what a Gas turbine power station presents Advantages Disadvantages It is simple to design & construct compared to a Steam Power station, since no boilers are required. Problem of starting. Compressor needs to be operating thus external source of power is necessary. Much smaller compared to Steam Power station of same capacity Net output is low since greater power is used to drive compressor. Lower operating costs Overall efficiency of plant is low ≈ 20% because of exhaust gases still containing heat. only efficient in a Combined cycle configuration Less water used since there is no need for a condenser Temperature of combustion chamber is too high thus resulting in a lower life. Maintenance charges are low . Can be started quickly . No stand-by losses .

This schematic diagram must be properly understood. it is the basis upon which Typical Gas turbine power station designs are done. the individual power station complexity may differ slightly to the schematic and yet over and above that will use the same principle.