Co-production of hydrogen, power, and liquid carbon dioxide in an integrated methane partial oxidation plant with zero-direct-emission: Thermodynamic and economic assessment

This study introduces a zero-emission cogeneration process that combines methane partial oxidation, recuperating organic Rankine cycle, CO₂ capture and storage, and hydrogen-fueled steam Rankine cycle through cascade heat recovery. The process is modeled in Aspen HYSYS and analyzed using energy, exergy, and thermoeconomic methods. Under standard conditions, the plant consumes 25 MW of fuel, generates 1164 kW of net power, and produces 487.5 kg/h of H₂ and 4851 kg/h of liquid CO₂, with overall thermal and exergy efficiencies of 66.03 % and 64.58 %, respectively. The specific fuel consumption is 1.514, and the specific reboiler duty is 4.11 MJ/kg CO₂, as the partial oxidation reactor supplies all solvent-regeneration heat with a heat-recovery efficiency of 83.78 %. Exergy analysis shows that the reforming unit and partial oxidation reactor account for about 66 % of total exergy destruction. Sensitivity analysis indicates that increasing the organic Rankine turbine inlet temperature to 600 °C and reducing oxygen flow to the partial oxidation reactor to 0.82 kg/s can boost exergy efficiency to 70 %, raise net power to 1,393 kW, and lower the energy cost from 1.354$/kWh, resulting in a payback period (PBP) of 8.54 years. The geographical analysis indicates that Turkmenistan provides the lowest Levelized cost of hydrogen, at approximately 3.01 $/kg H₂, whereas Italy offers the shortest PBP, at approximately 4.7 years.