Exergy and Environmental Impact Assessment between Solar Powered Gas Turbine and Conventional Gas Turbine Power Plant

Ali Rajaei,Hasan Barzegar Avval,Elmira Eslami

doi:10.1155/2016/8323859

Abstract

Recuperator is a heat exchanger that is used in gas turbine power plants to recover energy from outlet hot gases to heat up the air entering the combustion chamber. Similarly, the combustion chamber inlet air can be heated up to temperatures up to 1000 (°C) by solar power tower (SPT) as a renewable and environmentally benign energy source. In this study, comprehensive comparison between these two systems in terms of energy, exergy, and environmental impacts is carried out. Thermodynamic simulation of both cycles is conducted using a developed program in MATLAB environment. Exergetic performances of both cycles and their emissions are compared and parametric study is carried out. A new parameter (renewable factor) is proposed to evaluate resources quality and measure how green an exergy loss or destruction or a system as a whole is. Nonrenewable exergy destruction and loss are reduced compared to GT with recuperator cycle by 34.89% and 47.41%, respectively. Reductions in CO2,NOx, and CO compared to GT with recuperator cycle by 49.92%, 66.14%, and 39.77%, respectively, are in line with renewable factor value of around 55.7 which proves the ability of the proposed green measure to evaluate and compare the cycles performances.

Highlights

Recuperation as one of the conventional optimization enhancements in gas turbine cycles by preheating inlet air entering combustor which decreases fuel consumption rate dramatically leads to less greenhouse gas emissions
Several studies are conducted on energy and exergy analysis of hybrid solar gas cycles [2]
It is proved that hybrid solar gas turbine cycles are more efficient in terms of CO2 emission prevention compared to conventional gas cycle with recuperator

Summary

Introduction

Recuperation as one of the conventional optimization enhancements in gas turbine cycles by preheating inlet air entering combustor which decreases fuel consumption rate dramatically leads to less greenhouse gas emissions. Renewable sources integration with power cycles with the aim of increasing total exergy efficiency based on different scenarios is performed by them. Several studies are conducted on energy and exergy analysis of hybrid solar gas cycles [2]. Schwarzbozl et al [4] using advanced software tools carried out design optimization and performance prediction of the solar tower gas turbine power plants. It is proved that hybrid solar gas turbine cycles are more efficient in terms of CO2 emission prevention compared to conventional gas cycle with recuperator. SOx which is prevented by preoperations in all gas cycles is considered negligible in modeling This analysis is aimed at quantitatively addressing the impact of renewable and nonrenewable sources on environment by introducing renewable factor. (iii) To propose renewable factor which helps in comparing renewable and nonrenewable sources quantitatively and more accurately

System Description and Assumptions

Formulation

Recuperator

Results and Discussion

Conclusions