Exergoeconomic and Sustainability Analysis of Reheat Gas Turbine Engine

Abstract

Exergoeconomic and sustainability analyses have been performed for a heavy duty industrial reheat gas turbine engine. The proposed system was inspired by a GT26, Alstom advance-class gas turbine with a unique design modification based on the reheat principle using two sequential combustion chambers. The IPSEpro software package was used for validating the process and results tested against the manufacturer’s published data. Energy system performance is usually evaluated through energetic or exergetic criteria. The latter has the advantage of determining energy degradation and quantifying the deficiencies within a system as well as recognizing loss sources and types. The cost-effectiveness of using this gas turbine engine has been evaluated using exergoeconomic approach: the Specific Exergy Costing [SPECO] method. The sustainability of the proposed model was estimated using a generic combustor model, HEPHAESTUS, to appraise the emissions impact. The performance of gas turbine engines has been investigated for different load demand and climatic conditions using two configurations. The first system, Case-I, was a simple gas turbine (SCGT) engine, and the second, Case-II, a reheat gas turbine (RHGT) system. The reheat system boosted power output in RGHT, at the same time, reducing exergetic efficiency because of greater fuel consumption. Operating both systems at low ambient temperature is preferable and full load reduces waste exergy. The production cost on an exergy basis demonstrates that the RHGT has a lower value at 7.58 US$/GJ while the SCGT produces energy at 7.77 US$/GJ. From a sustainability perspective, the SCGT shows lower emission levels and has lower environmental impact than the RHGT.