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Asahi Kasei to construct biogas purification system at sewage treatment plant

| By Mary Bailey

Asahi Kasei Corp. (Tokyo, Japan) and Kurashiki City concluded an agreement to hold a trial to evaluate and demonstrate the performance of a biogas purification system at a sewage treatment plant in the city. Earlier, the Mizushima Works of Asahi Kasei’s Production Center and Kurashiki City concluded a comprehensive partnership agreement focused on carbon neutrality. Advancing the demonstration trial for decarbonization is one of the provisions of the partnership.

asahi kasei

Kojima Sewage Treatment Plant, Kurashiki, Okayama Prefecture, Japan (Source: Asahi Kasei)

The system refines high-purity methane gas (biomethane) by removing CO2 from biogas utilizing Asahi Kasei’s newly developed adsorbent, K-GIS zeolite, which selectively adsorbs CO2. Unlike conventional adsorbents which adsorb methane together with CO2, K-GIS zeolite adsorbs almost no methane. This enables the System to efficiently separate and recover high-purity methane while recovering high-purity CO2

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 and the U.S.

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. If biomethane production using the System is combined with carbon capture and utilization or storage (CCUS), the cycle would be carbon negative. In the demonstration trial, the separated gases are recombined to biogas as fuel for generating electricity.

Asahi Kasei will design, install, and operate the System, and evaluate and demonstrate its performance. Fabrication of equipment will occur in November 2022, with the start of installation in May 2023. Operation is expected to begin at the end of 2023

Commercialization of the system is expected around 2025 or 2026 following additional trials in countries or regions where biogas purification is performed. The technology will also be applied to CO2 separation and recovery from gases other than biogas.