THERMODYNAMIC ASSESSMENT OF S-CO2 BRAYTON CYCLE INTEGRATED WITH CASCADED LIBR-H2O AND TRANS-CO2 VAS FOR WASTE HEAT RECOVERY OF GAS TURBINE ENGINE.

Abstract

With rising global oil costs and growing environmental consciousness, the power sector is grappling with how to enhance gas turbine efficiency and minimise pollutant emissions from gas turbines. Waste heat recovery is an efficient way to increase gas turbine fuel efficiency and assist future turbines satisfy the more demanding Energy Efficiency Design Standard. In the present study, thermodynamic modelling and analysis of waste heat recovery comprising of Supercritical Carbon Dioxide recompression Brayton cycle, Transcritical Carbon Dioxide cycle, water lithium bromide vapour absorption system has been proposed for Gas turbine application based on first and second law thermodynamic laws. Thermodynamic performance of standalone Supercritical Carbon Dioxide Recompression Brayton cycle was compared with the proposed Design on the basis of standard operating design conditions. For thermodynamic analysis of combined system, high temperature exhaust gas of TitanTM 350 (Designed by Solar turbines-a Caterpillar company) was utilised. Energic efficiency of standalone SRBC was found to be 35.92 % while Exergic efficiency was found to be 60.26 %. The overall thermal efficiency of proposed cycle was found to be 40.37% which signifies that waste heat can be recovered efficiency when combination of cycles is used. It was also found that the variation of important parameters such as compressor inlet temperature, turbine inlet temperature, and pressure ratio have a significant effect on the performance on standalone supercritical carbon dioxide recompression Brayton cycle.