Comparative exergy analysis between liquid fuels production through carbon dioxide reforming and conventional steam reforming

Gas-to-liquid fuels technology has been deemed as an important implement to address the domestic oil shortage with the conversion of syngas into liquid fuel through Fischer-Tropsch synthesis. In this study, we propose a more effective approach (a novel carbon looping cyclic reforming) to aid such necessity based on quantifying the benefits of such process by comparison with conventional steam methane reforming. Our approach is underpinned by using a reformer with a water-gas shift reactor that enables the acquisition of an optimal H-2/CO ratio. As such, adjustment of H-2/CO ratio in syngas can be easily attained, beneficial to downstream Fischer-Tropsch synthesis, ultimately minimizing exergy destruction. We find that, with conventional steam methane reforming as reference, the exergy efficiency of this novel process could be increased by 4.34 percentage points, with simultaneously reducing exergy destruction in syngas production unit by 5.17 kJ/mol CH4. Further, the exergy destruction in Fischer-Tropsch synthesis is cut down by 13.98 kJ/mol by adoption of one-through pass of unreacted gas. (C) 2018 Elsevier Ltd. All rights reserved.