COMBINED GAS/STEAM TURBINE POWER PLANTS. THE PRESENT STATE OF PROGRESS AND FUTURE DEVELOPMENTS.

The term 'combined gas/steam turbine plant' is understood to signify the joint operation of a gas turbine with a steam turbine cycle, in which the waste heat from the gas turbine is utilized in a heat recovery boiler to generate steam which is then fed to a steam turbine. Of the many combined cycles proposed for the improvement of the overall efficiency the combination of gas and steam processes is the only solution which has gained a place in practical application - in the transformation of thermal into electrical energy and in the cogeneration of heat and electricity. Due to the fact that the gas turbine process is characterized by a high upper temperature and the steam turbine process by a low temperature at the 'cold end', a high Carnot efficiency is attained. The high and sometimes very high efficiencies are, indeed, the reason for the success of this type of installation during the last 25 years. The contribution presents a review of the arrangements which can be provided today, and of the attainable outputs and efficiencies.