In the city of Bitburg in Germany, a newly built biogas pipeline will soon bundle raw biogas supplies of up to 48 biogas plants from the German region.

The 45 kilometer-long pipeline will transport the renewable energy source to a central upgrading plant at the Bitburg commercial, service and leisure center area. There it will be refined into biomethane, a natural gas equivalent renewable alternative then fed into the gas grid.

The core of the project is the biomethane upgrading plant of ETW Energietechnik, a German energy company.

The future of biogas

The biogas plant network in the region can produce around 10,000 cubic meters of raw biogas per hour. Since May 2020, an initial seven plants have been sending 1800 cubic meters per hour of biogas to the upgrading plant-which corresponds to an annual volume of around 64 million kilowatt-hours.

With this volume, a good third of the annual natural gas demand of the nearby district town of Bitburg (14,000 inhabitants) can be covered. The processing plant comes from the biogas upgrading specialists ETW Energietechnik in Moers, Germany. It is based on the established ETW SmartCycle PSA technology, which was developed by ETW's own design team.

How is the biogas upgrading done?

In the module, up to about 1800 cubic meters of raw biogas are upgraded every hour by removing CO2 and other undesirable elements, converted into biomethane and finally fed into the natural gas grid of the Trier public utility company," explains Dr. Oliver Jende, responsible sales manager at ETW Energietechnik GmbH.

Biogas upgrading is used to refine biogas with a composition of about 50 percent CH4, the rest CO2. With this plant, the CO2 portion is separated from the main gas stream, thus producing a product gas interchangeable with natural gas that can be fed into the natural gas grid via a downstream feed-in plant.

The gas components are separated by means of pressure swing adsorption (PSA), a physical process for separating gas components under pressure by adsorption. The separation effect is achieved because one of the components to be separated (CO2) adsorbs more strongly than the other (CH4). This results in an enrichment of the less adsorbing component (CH4) in the gas phase.

Advantages

A particular advantage of the ETW SmartCycle PSA compared to other biogas upgrading processes is the dynamic adaptation to fluctuating raw gas compositions. This is done automatically according to the desired purity of the product gas and the volume flow by adjusting the cycle speed.

The benefits of the ETW process for the users have now also spread around the world. ETW Energietechnik has received another order to deliver the first ETW SmartCycle plant to Canada.

ETW Energietechnik GmbH can count itself among the companies in the energy sector that are even creating new jobs in these difficult times.

The following are just some of the advantages of the ETW SmartCycle PSA gas upgrading process:

• Lowest energy consumption of all biogas upgrading processes
• Simple process control and high availability (reference plants with 99% availability)
• Fully automatic startup and turndown - Function
• Methane content in the product gas adjustable between 96 and 99%
• Guardbed to protect the adsorber filling
• Absorbent service life of more than 15 years
• No chemical and biological risks as the process is completely dry