Integration of the Brayton and Rankine cycle to maximize gas turbine performance--A cogeneration option

The Brayton and Rankine cycles are well known and widely used in their own way to generate power. A combining of the fluids of the two cycles has been proposed by International Power Technology and tested by Allison Gas Turbine Operations. Steam generated by the exhaust heat is mixed with the fuel and air in the gas turbine combustion chamber prior to expansion through the turbine.The thermal efficiency of an existing engine can be increased by 40% and power output by 60% at constant turbine temperature. This concept is identified as the Dual Fluid Cycle (DFC).In addition to the basic improvement in cycle performance, the DFC provides an added degree of flexibility to the power plant engineer in his effort to satisfy plant needs for power, heat, and steam.Allison test results of this concept on a Model 501-KB engine have been correlated with a computer model of the engine and show good agreement. This paper will show how the DFC can be used to maximize thermal efficiency while meeting the requirement for power and steam in selected cases. Comparisons will be made to other options for power and steam generation.Copyright © 1984 by ASME