Performance and Cost Analysis of Natural Gas Combined Cycle Plants with Chemical Looping Combustion

The natural gas combined cycle (NGCC) is the most popular and efficient fossil fuel power plant; however, integrating a carbon capture system reduces its performance efficiency. The demand to reduce the carbon capture cost and improve eco-friendliness drives the development of alternatives. In this study, four alternative NGCC-based process schemes were designed: NGCC with amine carbon capture as a base configuration and NGCCs with three different chemical looping combustion (CLC) configurations. Detailed heat and material balances were evaluated for all four cases using the PRO/II simulation package. A comparative analysis of the gross and net power, plant efficiency, and carbon capture efficiency, which are imperative to optimizing the process configuration, was conducted for all of the proposed cases. All NGCC-CLC processes could produce higher net power than NGCC-MEA because the amine regenerator consumes a high amount of power in its operation. In the condition using an equal amount of natural gas supply, NGCC-CLC configurations using excess air could produce a net power of 510.1 MW with a plant efficiency of 44.35%. The excess air fed in both cases enabled the turbine to generate more power. NGCC-CLC using excess air with steam turbine integration has an investment cost of 132.9 $/net MWh, an operating cost of 56.7 $/net MWh year, and a levelized cost of electricity of 90.9 $/MWh. In addition, NGCC-CLC with excess air resulted in a carbon capture efficiency of 99.93% under 59.2 $/ton of CO2, which was higher than that of NGCC-MEA with a carbon efficiency of 95.1%. NGCC-CLC using excess air with steam turbine integration is considered as the most efficient process scheme for generating power from natural gas with regard to efficiency, cost, and environmental impact.

Automated summary

This study designed four alternative NGCC-based process schemes and found that NGCC-CLC processes could produce higher net power than NGCC-MEA. Among them, NGCC-CLC with excess air and steam turbine integration was considered as the most efficient process scheme for generating power from natural gas.