A research group comprised of Koji Kuramoto, Research Group Leader, Fumihiko Kousaka, researcher, and Liu Yanyong, lead researcher of the Energy Conversion Process Group of the Energy Process Research Institute (EPRI), National Institute of Advanced Industrial Science and Technology (AIST), together with Professor Atsushi Urakawa of Delft University of Technology in the Netherlands, have successfully developed a technology to synthesize high density methane from low density CO2, across a range of CO2 densities, from trace atmospheric CO2 to CO2 released by power plants, without the need for preprocessing using a CO2 separation and capture process.
Technology to capture CO2 emissions from power plants and other industrial sources, as well as CO2 already released into the atmosphere, and convert it into hydrocarbon fuel or other useful carbon compounds is essential for achieving carbon neutrality. Unfortunately, that CO2 is diluted by other gases, such as nitrogen and oxygen, with a density of only 400 ppm in the case of the atmosphere. As such, CO2 separation and capture must be carried out, at great cost and energy, before the CO2 becomes available for use. According to Kuramoto, "To date we have been searching for a technology to capture CO2 from industrial and civil sources, or CO2 in the atmosphere, and convert it to useful carbon compounds such as hydrocarbon fuel, without the need for separation and capture."
The solution the team found was to develop a bifunctional catalyst that can both absorb CO2 and also convert it to methane by causing it to react with hydrogen. This technology to directly capture and convert trace CO2 uses little energy and does not require a CO2 separation and capture process. The technology enables the direct synthesis of methane at high densities of over 1,000 times atmospheric levels using only CO2 at densities of only 100 ppm, lower than is present in the atmosphere.
Kuramoto adds, "The strength of the technology is that it does not need a carbon gas concentration method, such as the amine absorption method. We will continue our research moving forward to develop a low cost, high efficiency catalyst, and a continuous process using said catalyst, in order to make the technology available for practical application."
■Bifunctional catalyst: unlike normal catalysts that have only one function, such as converting CO2 to methane, this catalyst has both the function of selectively absorbing CO2 for capture and the function of converting it to methane.
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