Japanese chemical company Asahi Kasei has begun a demonstration of its biogas purification system at the Kojima Sewage Treatment Plant in Kurashiki, Japan, using zeolite-based CO2 separation technology.
The trial, launched in collaboration with Kurashiki City, aims to refine biogas by removing CO2 and recovering high-purity methane (biomethane) as a substitute for natural gas. The system separates CO2 and methane using a pressure vacuum swing adsorption (PVSA) process, where zeolites, porous minerals with microscopic channels, selectively absorb CO2.
Biogas, produced from sewage sludge, food waste and organic material, typically contains 60% methane and 40% CO2. Biomethane is already a growing low-carbon fuel in Europe and the US, but improved separation and purification could help scale its use in Japan.
Asahi Kasei is responsible for the design, installation and operation of the system, while Kurashiki City supplies the biogas and hosts the trial. If successful, the company plans to commercialise the technology by 2027 and expand trials to other regions where biogas purification is already in use.
“We are excited to start this on-site demonstration, which showcases our zeolite and PVSA process technology,” said Osamu Matsuzaki, Senior Executive Officer at Asahi Kasei. “We aim to accelerate the adoption of this technology to reduce environmental impact and contribute to sustainability.”
Beyond biogas purification, the system could support carbon capture, utilisation and storage (CCUS), where separated CO2 is stored or repurposed, potentially making the process carbon negative.
