On-site demonstration trial on CO₂ separation/recovery utilizing zeolites

Asahi Kasei and Kurashiki City held a grand opening ceremony on February 4, 2025, for a biogas purification system (the System) in Kurashiki, Okayama Prefecture, Japan. The System uses Asahi Kasei’s CO₂ separation/recovery technology utilizing zeolites installed at a sewage treatment plant. The goal of this collaboration is to evaluate and demonstrate the performance of the System.

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Kaori Ito, Mayor of Kurashiki City (fourth from right), and Osamu Matsuzaki, Senior Executive Officer of Asahi Kasei (fourth from left), were among the attendees of the grand opening ceremony (Photo: Business Wire)

Asahi Kasei and Kurashiki City concluded a comprehensive partnership agreement for the realization of carbon neutrality in society on September 15, 2022. Advancing the demonstration trial for decarbonization is one of the provisions of the partnership.

The System separates CO₂ and methane from biogas using the optimum combination of a special zeolite as adsorbent that selectively adsorbs CO₂ and a special pressure vacuum swing adsorption (PVSA) process technology. The zeolite is a crystalline aluminosilicate having regular channels (pores) controlled on the order of angstroms (ten-millionths of a millimeter) and cavities (voids) with a specific surface area exceeding several hundred square meters per gram. Asahi Kasei’s PVSA process technology, which separates specific gases by changes in pressure, enables the removal of CO₂ from biogas to refine high-purity methane gas (biomethane) at a high recovery rate.

Biogas from sewage sludge, garbage, etc., consists of approximately 60% methane and 40% CO₂. While the use of biogas as a carbon-neutral fuel is rapidly expanding, it is also a source of biomethane as a substitute for natural gas in Europe, the U.S., and other regions.¹

In Kurashiki City, electricity is generated using biogas derived from sewage sludge at the Kojima Sewage Treatment Plant. The System will use a portion of this biogas for the demonstration trial. Furthermore, if the CO₂ separated by this System is utilized and/or stored, it would achieve carbon capture, utilization, and storage (CCUS), which is carbon negative. In the demonstration trial, the separated methane is returned and used as fuel to generate electricity for effective utilization of the biogas.

The demonstration trial at the Kojima Sewage Treatment Plant began in February 2025. Asahi Kasei is responsible for the design, installation, and operation of the System, as well as evaluating and demonstrating its performance, while Kurashiki City supplies biogas generated from sewage sludge in addition to providing the site for the trial.

Commercialization of the System is expected around 2027 following additional trials in countries or regions where biogas purification is performed.

“We are excited to start the on-site demonstration trial of a biogas purification system using Asahi Kasei's zeolite and PVSA process technology,” says Osamu Matsuzaki, Senior Executive Officer of Asahi Kasei and Senior General Manager of Corporate Research & Development. “As the next step, by expanding co-creation partnerships globally, we will accelerate the advancement and practical implementation of this outstanding technology that can reduce environmental impacts, contributing to sustainability for the world.”

¹ Please refer to the following webpages

International Energy Agency | Special section: Biogas and biomethane

https://www.iea.org/reports/renewables-2023/special-section-biogas-and-biomethane

European Commission | Biomethane

https://energy.ec.europa.eu/topics/renewable-energy/bioenergy/biomethane_en

Related press release: “Asahi Kasei to construct biogas purification system at sewage treatment plant in Kurashiki, Okayama, Japan”

https://www.asahi-kasei.com/news/2022/e220915_2.html

Information on the sustainability of the Asahi Kasei Group

https://www.asahi-kasei.com/sustainability/about_sustainability/

About Asahi Kasei

The Asahi Kasei Group contributes to life and living for people around the world. Since its foundation in 1922 with ammonia and cellulose fiber business, Asahi Kasei has consistently grown through the proactive transformation of its business portfolio to meet the evolving needs of every age. With more than 49,000 employees worldwide, the company contributes to sustainable society by providing solutions to the world’s challenges through its three business sectors of Material, Homes, and Health Care. For more information, visit www.asahi-kasei.com.

Asahi Kasei is also dedicated to sustainability initiatives and is contributing to reaching a carbon neutral society by 2050. To learn more, visit https://www.asahi-kasei.com/sustainability/.

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