A method of converting captured carbon dioxide (CO2) into methane developed by researchers at the US Department of Energy’s Pacific Northwest National Laboratory (PNNL) could see carbon capture costs being reduced by a significant amount, according to the study.
Using a solvent known as EEMPA the researchers were able take CO2 from power plant flue gas before binding it and turning it into useful chemicals such as methane.
This method was found to be considerably cheaper than the existing process of methane conversion. The research discovered that the initial investment cost was 32% lower, operation and maintenance costs 35% lower, and the overall selling price of the synthetic natural gas being reduced by 12%.
The study follows previous PNNL research which found that, by using EEMPA in power plants, carbon capture could be reduced by 19% compared with standard industry costs.
In addition to being a cheaper method of CO2 to methane conversion, the use of EEMPA could help reduce the impact the gas industry has on the environment.
Jotheeswari Kothandaraman, lead author and chemist, PNNL, spoke about the opportunity to lower carbon emissions, saying, “Right now a large fraction of the natural gas used in the US has to be pumped out of the ground.”
“The methane produced by this process – made using waste CO2 and renewably sourced hydrogen – could offer an alternative for utilities and consumers looking for natural gas with a renewable component and a lower carbon footprint.”
EEMPA also allows for easy dissolution of CO2 when capturing the gas that’s emitted from chimneys in plants. The captured CO2 can then be converted to methane on site by mixing it with renewable hydrogen and a catalyst inside a chamber. The mixture is then heated to half the pressure required by conventional methods of CO2 to methane conversion, reducing further the energy required.
The research team plans to apply the same process that works for methane to methanol, as methanol has many more practical applications. The possibility of using captured CO2 to manufacture plastics is also being investigated by the team.