Performance Enhancement of Gas Turbine Power Plant via Wet Compression Technique and Its Effects on Economic Aspects

The study is intended to improve the performance of gas turbine engines to meet both electrical power demand and peak load in the power plant and to analyze their economic aspects. Performance enhancement of gas turbine was analyzed using thermodynamic modelling and focusing on power enhancement, specific fuel consumption (SFC), heat rate and thermal efficiency due to the application of wet compression system. The study was conducted on the two gas turbine units (GT1 and GT2) in the Pesanggaran power plant, Southern Bali Island, Indonesia between December 2014 and March 2015. GTPro, a power cycle thermodynamic computer modeling software program, was utilized to conduct the performance evaluation of the application of wet compression system. The study was conducted based on three conditions, i.e. saturated fogging and wet compression at 1% and 2% over spray (OS). The capacity cost, operating cost, and payback period due to the investment cost of the system are determined using PEACE. Based on the results of evaluation, performance enhancement of gas turbines using wet compression system is more significant than with conventional fogging, with maximum incremental power reaching 23.09%. In addition, in terms of SFC, heat rate and thermal efficiency, the wet compression system is more economical than conventional fogging; therefore the application of the wet compression system on GT1 and GT2 can achieve the fastest payback in, respectively, 9 and 10 year. It can be concluded that the wet compression system is more effective and economical than conventional fogging for improving the performance of gas turbines. However, the experimental work to validate a thermodynamic modelling and the effects of adding water to gas turbine components needs be further investigated.