Thermodynamic, Environmental and Economic Assessment of Exhaust Gas Recirculation for NOx Reduction in Gas Turbine Based Compressor Station

Abstract

A thermodynamic, environmental and economic assessment of an exhaust gas recirculation (EGR) system for NOx reduction has been carried out on an RB211 gas turbine based compressor station. The configured system was evaluated using a commercial process simulation software ASPEN PLUS® for the EGR process, along with a one dimensional model for the prediction of NOx. The assessment was focused on a realistic system of 20% gas recirculation cooled 300 °C with an aerial cooler. Detailed economic analysis based on present value cost per unit mechanical energy (kWh), showed that there is no economic advantage in implementing an EGR system in an existing gas turbine based station. Although the environmental cost was lower with the EGR system, it was offset by the cost of the EGR system itself combined with the additional incremental cost of fuel due to the decrease in the thermal efficiency.