The operator of a biogas facility near Koblenz is realigning its plant’s concept by turning to biomethane production, and has commissioned Hitachi Zosen Inova BioMethan to construct a membrane system with the capacity to handle 500m³/h of raw biogas.

At the beginning of April 2016, the plant operator commissioned the Zeven-based specialists Hitachi Zosen Inova BioMethan GmbH (HZI BioMethan) to construct a gas upgrading facility, to be realized with a membrane-based gas permeation system with a raw biogas capacity of 500 Nm³/h. The membrane technology separates the carbon dioxide (CO2) contained in the biogas from the methane. The biomethane produced as a result of this scrubbing and subsequent upgrading to natural gas quality will be fed into the natural gas grid of the local network operator from February 2017.

The operating company has been producing biogas from organic and industrial waste and converting it into electricity in three CHP plants since 2002. In light of the imminent expiry of the feed-in tariffs for electricity under the German Renewable Energy Act (EEG), the operator was seeking economically viable alternatives for the future. HZI BioMethan was able to offer a solution that was ideally aligned to the performance requirements and the specific conditions at the location: gas upgrading to produce biomethane.

Part of the raw biogas will still be converted into electricity. The resultant CHP waste heat is used to provide the heating required for waste hygienization. The remainder of the biogas will be upgraded to high-quality biomethane. “Coupled with our development expertise and many years of project experience, it was the choice of two processes that was crucial,” said Dr. Karsten Wünsche, CEO of HZI BioMethan, commenting on the decision to award the contract. Given that the CHP waste heat is required elsewhere, the pressure-driven membrane system fulfills the operator’s needs. HZI BioMethan will deliver the system using a specifically designed modular container construction.

Fresh prospects for aging biogas plants

There are many biogas plants that have already been in operation for more than 15 years; cogeneration plants are due for renovation, and feed-in tariffs under the EEG are scheduled to expire. Looking to the future, retrofitting biogas facilities with a gas upgrading system offers attractive advantages from both the economic and ecological perspectives: “Selling gas is a lucrative and forward-looking business model for many operators of biogas plants,” stressed Wünsche.


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