SELECTION OF OPTIMUM HEAT EXCHANGER IN DUAL GAS TURBINE COMBINED CYCLES

Abstract

ABSTRACT

This paper studies the desired heat exchanger located between the gas topping cycle and air bottoming cycle in sight of characteristics, performance, and optimizing design aspects among the plant power generation cycle. The performance of the combined power cycle with the desired heat exchanger is investigated under different operating conditions for different available types and arrangements of such heat exchangers. Various mathematical models including geometry, operation, performance, and economy are introduced. Several numerical correlations are worked on to transform the literature published data to thermoeconomic mathematical relationships. Our own computer software package is established to carry out the evaluation, design, and optimization processes. The Plain plate-fin surface 2.0 heat exchangers are employed with unmixed fluids for each cross-flow and counter-flow arrangements, while two Westinghouse gas turbines of 160 and 32.2 MW, are implemented, transporting 435 kg/s flue gases and 199 kg/s air, respectively.

The study considers simple cycles, cycles with one intercooler, or with two intercoolers. Various and detailed parametric, and optimization study outcomes are achieved. There is a linear relation among counter-flow heat exchanger effectiveness and plant power cycle efficiency, with a rate of each 0.1 effectiveness improvement gives 1.25 % rise in the efficiency. For Plain Plate-Fin Surface 2.00, counter-flow arrangement, at the optimum line, the net savings grow up to 30 and 54%, for plants with one and two intercoolers, respectively, based on the simple case with 2.7 MUSD. This heat exchanger augmented with two intercoolers in the cycle, through dimensions of 1.77 m x 5.03 m x 10.06 m, is the optimum one, has the highest energy savings, efficiency, and effectiveness, with net energy savings of 4.1 MUSD and mass of 136 Ton.https://jer.ly/PDF/Vol-35-2023/JER-03-35-Abstract.php?f=a