Toray Industries has innovated a CO2 separation membrane with a dual all-carbon structure, including a hollow porous carbon fiber as a carrier, and a thin carbon membrane layer.
This separation membrane provides excellent CO2 separation and durability, and is more suitable for manufacturing more compact facilities than traditional inorganic separation membranes. Toray will accelerate research and development and deploy this separation membrane in social infrastructure.
CO2 separation technology is essential for the use of CO2 to achieve a circular economy. This technology usually uses absorption and adsorption facilities, but the problem with such facilities is that they consume too much energy, which promotes the global research on energy-efficient separation membrane technology.
The pore diameter of the separation layer is less than 1 nanometer. Because it is thinner, it provides better gas permeability, but the low pressure resistance needs to be combined with the carrier layer. The ordinary inorganic carrier layer is hard and fragile, and the diameter cannot be reduced, which affects the packaging and miniaturization of dense components.
In 2019, Toray created a porous carbon fiber with a continuous pore structure. This fiber can provide a carrier layer for gas separation membranes. By creating a hollow fiber, it provides good air permeability, chemical resistance and heat resistance.
The company's new CO2 separation membrane uses a thin hollow porous carbon fiber with a diameter of less than 300 μm as the carrier layer, and the surface is a uniform carbon membrane separation layer that is only a few microns thick.
Since the carrier layer and the separation layer are independent of each other, this separation membrane provides excellent CO2 separation and durability. It is very flexible and very thin, just like ordinary fiber, which can realize continuous production. Compared with the traditional organic CO2 separation membrane with the same volume, this high density can realize the miniaturization of the module, and the CO2 permeability is 5 times larger.
One potential application of Toray's new separation membrane is the purification of natural gas and biogas. It can also be used for hydrogen production and purification, CO2 waste gas separation, and the use of functional layers to separate other gases according to the gas to be separated.