Title: Exergetic analysis in a combined gas-steam power cycle with two regenerators in parallel

Authors: Nattan Roberto Caetano; Eduardo Xavier Barreto; Ana Cristina Ruoso; Marcos Antonio Klunk; Paulo Roberto Wander

Addresses: Mechanical Engineering Department, Federal University of Santa Maria, Roraima Street 1000, 97105-900 Santa Maria, Brazil ' Mechanical Engineering Department, Federal University of Santa Maria, Roraima Street 1000, 97105-900 Santa Maria, Brazil ' Production and Systems Engineering Department, Federal University of Santa Maria, Roraima Street 1000, 97105-900 Santa Maria, Brazil ' Mechanical Engineering Department, University of Vale do Rio dos Sinos, São Leopoldo, Brazil ' Mechanical Engineering Department, University of Vale do Rio dos Sinos, São Leopoldo, Brazil

Abstract: This work presents an exergetic analysis applied in a configuration in which two regenerators were in parallel for a combined gas-steam power cycle. The working fluids considered for the gas and vapour cycles were air and water. In this case, two heat recovery steam generators vaporise water and reheat using a steam turbine second stage, where the full power cycle was 10,000 kW. A numerical study was performed from 100 to 7,000 kPa steam pressure. The exergy approach was performed in order to maximise the thermal efficiency. The benefits brought by two regenerators was an increase of 37% in the thermal efficiency. Also, the second regenerator reduces the lost exergy in the exhaust gases. Reductions of 81% were observed in the condenser.

Keywords: combined gas-steam cycle; exergy analysis; parallel regenerators.

DOI: 10.1504/IJHM.2020.107784

International Journal of Hydromechatronics, 2020 Vol.3 No.2, pp.109 - 127

Received: 30 Sep 2019
Accepted: 30 Oct 2019

Published online: 15 Jun 2020 *

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