Making Chemicals from Carbon Dioxide and Steam Using Electricity

This patent describes a process that uses electricity to split steam and then reacts the resulting hydrogen with carbon dioxide or carbon monoxide to create various carbon-based compounds, like fuels or plastics.

What it covers

This process uses an electrolyzer with a special proton-conducting membrane to convert steam and carbon gases into useful chemicals. First, steam is injected under pressure into the anode compartment (Claim 1). Water in the steam is oxidized at the anode, creating protonated species that travel through the proton-conducting membrane (Claim 1). These species are then reduced at the cathode surface, forming reactive hydrogen atoms (Claim 1). Simultaneously, carbon dioxide (CO2) and/or carbon monoxide (CO) are introduced under pressure into the cathode compartment (Claim 1). The reactive hydrogen atoms then reduce the CO2 and/or CO, forming compounds of the CxHyOz type, which are organic chemicals like hydrocarbons or oxygenates (Claim 1). For example, this system could take waste CO2 and steam, and using electricity, convert them into a liquid fuel such as methanol or ethanol.

What it doesn't cover

• —Does not cover electrolysis processes that do not use a proton-conducting membrane to separate the anode and cathode compartments.
• —Does not cover systems that produce only hydrogen gas without also reducing carbon dioxide or carbon monoxide into CxHyOz compounds.
• —Does not cover processes where carbon dioxide or carbon monoxide are reduced by hydrogen that was not generated directly from steam electrolysis within the same system.
• —Does not cover CO2/CO reduction methods that operate outside the specified temperature range of 200°C to 800°C (Claim 9) or pressure ranges for steam and CO2/CO (Claims 6, 8).
• —Does not cover the direct electrochemical reduction of CO2/CO without an intermediate reactive hydrogen step from steam.

The clever bit

The patent's innovation is the integrated system that uses a proton-conducting membrane to efficiently generate reactive hydrogen atoms from steam, and then immediately uses these atoms to reduce carbon dioxide or carbon monoxide within the same cathode compartment to form complex carbon compounds. This direct, in-situ conversion avoids the need to produce and store hydrogen separately, and allows for control over the final product type by adjusting electrical settings (Claim 2).

Why it matters

This technology aims to convert greenhouse gases like carbon dioxide and carbon monoxide into valuable chemicals or fuels. This approach offers a way to reduce carbon emissions by recycling carbon from industrial processes or the atmosphere. It could also provide a sustainable method for producing chemicals and energy carriers, lessening reliance on fossil resources.

Real-world examples

• 1.Carbon capture and utilization (CCU) systems
• 2.Synthetic fuel production (e-fuels)
• 3.Chemical feedstock production from waste CO2
• 4.Power-to-X technologies