According to the latest information released on the official website of Toray on April 15, the company has successfully invented a carbon dioxide (CO2) separation membrane with a dual all-carbon structure. This dual structure includes hollow porous carbon fibers as a support and a surface. The thin carbon film separation layer.
The membrane has excellent CO2 separation performance and high durability. Compared with the traditional inorganic separation membrane, the membrane can make the equipment more compact. It is reported that Toray will increase its research and development efforts in the future and deploy this separation membrane in social infrastructure.
CO2 separation technology is essential for the use of carbon dioxide to achieve a circular carbon economy. This technology usually uses CO2 absorption and adsorption equipment. However, the problem with such devices and technologies is that they consume too much energy, which has also promoted research on energy-saving membrane separation technology worldwide.
The separation layer with a pore diameter of less than 1 nanometer is thinner and has better gas permeability, but lower pressure resistance needs to be used in combination with the support layer. The conventional inorganic support layer is hard and fragile, and its diameter cannot be reduced, thereby preventing dense module packaging and miniaturization.
In November 2019, Toray successfully developed the world's first porous carbon fiber with continuous, nano/micron-scale pore structure. For the excellent properties and potential applications of this fiber, read "Japan Toray New Porous Carbon Fiber: Permeable, Excellent adsorption and conductivity" (read the original text). This porous carbon fiber with a continuous pore structure can provide a support layer for the gas separation membrane. By forming the hollow fiber, the gas separation membrane has excellent gas permeability, chemical resistance and heat resistance.
The company's new carbon dioxide separation membrane uses thin hollow fiber porous carbon fibers with a diameter of less than 300 microns as a support layer, and on the surface is a uniform carbon membrane separation layer only a few microns thick. Since the support layer and the separation layer are independent of each other, this separation membrane provides excellent CO2 separation and durability.
This CO2 separation membrane is very soft, very thin, and can be continuously produced like ordinary fibers. High-density packaging makes the module miniaturized. Under the same volume, the CO2 transmission rate can be 5 times higher than that of conventional inorganic CO2 separation membrane modules.
One potential use of Toray's new CO2 separation membrane is the purification of natural gas and biogas. It can select the gas to be separated by using the functional layer, and it can also be used for hydrogen production and purification, waste CO2 separation and other gas separation applications.