Thermodynamic and exergoeconomic analysis of a multi-generation gas-to-X system based on fuel-rich combustion to produce power, hydrogen, steam and heat

Besides paying more attention to renewables, developing efficient multi-generation systems fed by currently available energy sources is another pathway to sustainable development. Meanwhile, hydrogen production will play a key role in the green transition. The present work investigates a multi-generation gas-to-X system to produce power, hydrogen, steam, and heat from thermodynamic and economic points of view. The proposed system includes a gas turbine, a water gas shift reactor, membrane, inverted Brayton cycle and recuperated organic Rankine cycles. The partial oxidation of the rich mixture in the combustion chamber of the gas turbine results in the presence of a considerable amount of hydrogen in the combustion products, through which, in addition to generating power and heat, there can also be hydrogen production. Results showed that the cost of produced hydrogen ranges from 8.13 to 2.12 $/kg and the overall exergy efficiency ranges from 54 to 62% for equilibrium ratios of 1.65–2.9. Besides, the cost of power generated by the gas turbine and the total cost rate of the system at an equilibrium ratio of 2 is obtained to be 47.7 $/MWh and 248 $/h, respectively.