Statistical Analysis for Parametric Optimization of Gas Turbine-Steam Turbine Combined Power Cycle with Different Natural Gas Combustion

Abstract

The combined Gas Turbine (GT) and Steam Turbine (ST) power generation techniques plays important role in power production. The coal fired thermal power plants have maximum possible efficiency about 34-36% with all arrangements of reheating and regeneration thermal systems. The integration of GT power generation system with old coal based thermal power plant helps to re-powering of plant and utilization of exhaust energy of GT unit through heat recovery steam generator (HRSG) of ST plant. The proposed title of research deals two steps of analysis. Energy analysis is adopted as first step for performance and energy destruction evaluation purpose where as Multi Linear regression (MLR) method is introduced as second method for parametric optimization. The four natural gases have been considered in this analysis and investigate the suitable fuel gas performance as per operating condition of GT plant such as gas turbine inlet turbine temperature (GTIT), compression ratio (CR) and mass flow of gases. The result of this paper concluded as maximum exergy loss found in combustion chamber of GT system and exhaust flow system of ST system in terms of 41% and 8% respectively. The combined and exergetic efficiency of plant are estimated to be 41% and 38.5% respectively. In present statistical model 4 levels and 3 factors (Pressure ratio, operating temperature and type of fuel gases) have been considered. And overall efficiency, gas turbine efficiency, heat loss in GT plant, Exergy destruction in thermal utilities like Compressor, combustion chamber and gas turbine are investigated. The statistical modeling concluded that the comparative results of actual and predicted results at different compression ratio of combustible gases which is affects the overall performance of combined GT-ST plant. This study helps to justify possible efficiency improvement with identifying the irreversibilities of plant utilities.