Techno-economic assessment of the modified Allam cycle configurations with multi-stage pump/compressor for efficient operation in hot regions

Abstract

The Allam cycle is renowned for its zero-carbon power generation and high efficiency. However, it faces challenges in hot regions where there is no available cold source for carbon dioxide liquefaction, leading to deterioration in its performance. In this study, a multi-stage pump/compressor is introduced, aiming to enhance the net electric efficiency of the conventional Allam cycle. Various potential enhancement methods are explored and analyzed through comprehensive thermodynamic and economic analyses. Among the configurations under consideration, the Allam cycle combined with two-stage pump/compressor and bypass compressor exhibits the best performance, achieving a 6.71 % increase in the efficiency of the conventional cycle. For the conventional Allam cycle, the efficiency decreases by 0.42 % for every 1 ℃ increase in ambient temperature, however, it is 0.17 % for the Allam-MPC cycle, which indicates it is less responsive to changes in ambient temperature. Moreover, the economic performance of the proposed cycle is better than that of the conventional cycle, which has higher revenue and lower levelized cost of electricity. The capital costs of the modified equipment represent around 1.43 % of the total capital costs of the conventional Allam cycle, and the investment-increment payback period is less than 0.5 years when the ambient temperature exceeds 30 ℃. Sensitivity analyses suggest that the proposed cycle will be more economically viable in hot regions with lower natural gas prices and higher electricity prices. Overall, this study provides a promising approach to improving the performance of Allam cycle in hot regions and offering valuable references for its practical implementation.