2. Combined gas and steam cycles

2.1 Thermodynamic considerations

The use of gas turbines for VCC rehabilitation is limited to the development of certain combined gas-steam cycles.

Figure 1 shows the temperature ranges between which work extraction takes place for the installation of a steam turbine (ST), a gas turbine (GT) and a combined gas-steam cycle (GSCC). In the case of the steam cycle, work extraction takes place in the relatively low-temperature range. Although the temperature obtained from fuel combustion at the heat source of the thermal cycle can reach 1,800 to 2,000°C, the temperature of the steam usually does not exceed 540 to 570°C. On the other hand, the lower temperature of...