As the world faces destructive consequences of continuously ascending carbon footprint, capturing CO2 and transforming it to something as useful as fuel seem too good to be true. Yet, a team of scientists from Air Fuel Synthesis (AFS) have developed a system to capture CO2 and water from thin air and produce synthetic gasoline from them.
The system developed by AFS can be divided into four main processes:
- Capturing of CO2 from air: Carbon dioxide is captured from air by allowing the latter to enter a tower which atomizes sodium hydroxide. The two proceeds to a reaction producing sodium carbonate solution.
- Dehumidification of air: Water is captured from humid air through dehumidification that allows condensation of water from air.
- Electrolysis of sodium carbonate solution and water: The sodium carbonate solution produced from step one will be electrolyzed to form carbon dioxide. Meanwhile, water condensed from air is also electrolyzed to form hydrogen.
- Reaction of CO2 and hydrogen: A hydrocarbon fuel can then be made by reacting carbon dioxide and hydrogen. Depending on required form of fuel, various synthesis routes can be utilized. For instance, carbon monoxide/hydrogen mixture, also called Synthetic Gas (SynGas), can be formed. This SynGas can then be converted to desired fuels via Fisher-Tropsch reaction or to methanol first and from methanol to gasoline via Mobil methanol-to-gasoline reaction.
AFS’ prototype of the system is able to produce five to ten liters of liquid fuel per day.
The energy used for the electrolysis part is designed to come from a renewable energy source to maximize reduction in greenhouse gases emissions. Moreover, water for hydrolysis can be from any source as long as it can be made pure enough for the electrolyzer. This means that water recovered from wastewater systems can also be utilized for this application.
More process improvements can still be done with AFS’ system that one day, it may be possible to produce fuel directly from reacting carbon dioxide and hydrogen, omitting electrolysis step for carbonate solution.