Thermodynamic and thermoeconomic assessment of hydrogen production employing an efficient multigeneration system based on rich fuel combustion

The recent development of distributed multigeneration energy systems is changing the focus of producing different energy vectors from large centralized plants to local energy systems. A novel multigeneration system is designed in the present work to supply domestic energy demands of power, hydrogen and heating. The proposed system mainly consists of a supercritical CO₂ cycle, a gas turbine equipped with a rich-fueled combustion chamber, a membrane for hydrogen separation and a water-gas shift reactor. Feeding the combustion chamber with a rich fuel mixture leads to the availability of a significant hydrogen amount in the products, which can be separated and stored. Thermodynamic analysis revealed that the highest irreversibility belongs to the combustion chamber, which is responsible for almost half of total exergy destruction. The cost of the produced hydrogen is estimated to be 2.2–6.8 $/kg for a natural gas price of 9.51 $/GJ and equivalence ratios of 2.9–1.65. The overall energy and exergy efficiencies, hydrogen production rate, total system cost rate, and cost of produced electricity are found to be 75.1%, 58.9%, 40.6 kg/h, 222 $/h and 51 $/MWh, respectively, assuming an equivalence ratio of 2.