Conversion of Methane to Hydrogen and Synthesis Gas Using Bimetallic Oxygen Carriers

Hydrogen (H₂) produced from methane has garnered significant interest recently due to its environmental friendliness, abundance, and the wide range of commercial applications it can be used for. On a per unit weight basis, the amount of energy produced during H₂ combustion is higher than any other fuels.

Current commercial H₂ production is based on methods like steam methane reforming, coal or biomass gasification, electrolysis, and thermochemical process. Energy efficiency and H₂ price data indicate that methane steam reforming, methane partial oxidation, and coal gasification are currently the most cost effective techniques for H₂ production. However, these techniques generate large quantities of carbon dioxide (CO₂) and require additional processing steps that include a water-gas shift reactor for converting carbon monoxide to H₂ and CO₂, followed by a CO₂ separation step to produce a pure stream of H₂. In addition, most of the reactions involved in H₂ production (e.g., methane steam reforming) are endothermic and heat must be provided for the reaction. Traditionally, methane has to be combusted in air to provide heat for the reaction, which creates additional CO₂ that must be separated prior to storage.

This invention describes a new method to produce pure H₂ from methane by combining two processes: methane chemical looping process (CLC) for production of heat using a copper oxide-ferric oxide oxygen carrier and the production of H₂ from methane decomposition using the reduced copper oxide-ferric oxide oxygen carrier and the heat from the CLC process. In addition, carbon formed from the methane decomposition process can be used directly or can be converted to synthesis gas using steam gasification. This method is capable of producing pure H₂ with a storage ready CO₂ stream.