Techno-economic assessment of solar steam reforming of methane in a membrane reactor using molten salts as heat transfer fluid

• Published in: International journal of hydrogen energy Vol. 46; no. 71; pp. 35172 - 35188
• Main Authors: Giaconia, Alberto, Iaquaniello, Gaetano, Morico, Barbara, Salladini, Annarita, Palo, Emma
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 14.10.2021
• Subjects: Hydrogen production; Membrane reactor; Molten salt; Solar reforming; Steam methane reforming; Techno-economic analysis; Techno-economic analysis; Membrane reactor; Solar reforming; Hydrogen production; Steam methane reforming; Molten salt
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2021.08.096

This paper reports the results obtained in a techno-economic analysis of the Steam Methane Reforming (SMR) technology aided with solar heat, developed and demonstrated in the European FCH JU project CoMETHy: a compact membrane reformer heated with molten salt up to 550 °C allowed to simultaneously carry out methane steam reforming, water-gas-shift reaction and hydrogen separation. This reactor can be integrated with new generation Concentrating Solar Thermal (CST) systems to supply the process heat. Experimental validation of the technology has been successfully achieved in a pilot scale plant and the results recently published. In this paper, we introduce a fully-integrated scheme and operation strategies of a plant on the 1500 Nm3/h hydrogen production scale. Then, techno-economic analysis of this new solar-driven process is presented to evaluate its competitiveness. Considering a plant capacity of 1500 Nm3/h (pure hydrogen production) and today's costs for the methane feed and the CST technology, obtained Hydrogen Production Cost (HPC) are in the range of 2.8–3.3 €/kg for a “solar-hybrid” system with high capacity factor (8000 h/year operation) and 4.7 €/kg for a “solar-only” case, while HPC≅1.7 €/kg can be obtained with the conventional route under equivalent assumptions. However, a sensitivity analysis shows that the expected drop of the cost of the CST technology will bring the HPC around 2.4 €/kg for the “solar-hybrid” case and close to 3.4 €/kg for the “solar-only” case, thus making the cost of solar reforming closer to conventional SMR with CO2 capture and with wind/solar electrolysis in the future. In the “solar-hybrid” case total CO2 production can be reduced by 13–29% with 58–70% of produced CO2 recovered as pure stream (at 1.3 bar); in the “solar-only” case total CO2 production can be reduced by 52% and 100% of produced CO2 recovered as pure stream (at 1.3 bar). However, compared to the conventional route, CO2 avoidance costs are still relatively high (≥137 €/tonCO2) and process optimization measures required. Therefore, optimization measures have been outlined to increase the overall process efficiency and further reduce the HPC. •Solar reforming achieved using membrane reactors heated with molten salts at 550 °C.•A solar reforming plant producing 1500 Nm3/h H2 was designed and analyzed.•Operation modes were analyzed to continuously drive 24 h the solar reforming process.•H2 production cost from solar reforming approaches the one from conventional routes.•Reforming driven by solar heat & power allows up to 79% reduction of CO2 emissions.