ETW Energietechnik supplies the biomethane upgrading technology for a 45 km biogas grid

With a newly built biogas pipeline, the association „Biogaspartner Bitburg“ will in future bundle the raw biogas supplies of up to 48 biogas plants from the region. The 45-kilo- metre-long pipeline will transport the renewable energy source to a central upgrading plant at the Bitburg commercial, service and leisure centre area “Flugplatz Bitburg” from May 2020. There it will be refined to biomethane, a natural gas equivalent rene- wable alternative and fed into the gas grid.

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With this pipeline, the shareholders, SWT Stadtwerke Trier, the private waste manage- ment company Luzia Francois and Landwerke Eifel AöR, are creating the conditions for an important component of the green and decentralised energy transition. The core of the project is the biomethane upgrading plant of ETW Energietechnik from Moers - based on the established, efficient ETW SmartCycle ® PSA technology.

The biogas plant network in the region has a total potential to 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 CHP and biogas upgrading specialists ETW Energietechnik in Moers. It is based on the established ETW SmartCycle ® PSA tech- nology, which was developed by ETW‘s own design team. „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.

A particular advantage of the ETW SmartCycle® PSA compared to other biogas up- grading 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 plant consists of a total of four containers, in which the PSA units, the vacuum pumps, the compressors and the entire instrumentation of the system control are accommodated. „It also contains a comfortable control room from which not only the treatment plant can be operated but also the already connected and future biogas plants can be monitored,“ says Dr. Oliver Jende. „During the planning stage, we have already provided for the possibility of being able to adjust the future capacity at any time to the expected growth of the agricultural biogas plants“, Dr. Jende looks ahead. 

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. The setup will have a processing capacity of 1920 Nm3/h raw biogas and is the first biomethane project for ETW outside Europe.

In addition, ETW ist developing projects to produce both biomethane and liquefied CO2 according to EIGA Food grade.. In this combination the plant will enable a 100% CH4 yield, i.e. zero CH4 emissions and even a negative CO2 footprint. Also Land-fill gas upgrading plants are being designed, that are able to extract high amounts of Nitrogen (N2) from land-fill gas with the ETW SmartCycle ® PSA technology.ETW is thus gradu- ally establishing itself as a supplier of industrial biomethane plants.

Not least for this reason, ETW Energietechnik is currently in the process of doubling its production capacity at its headquarters in Moers. Construction work on the new hall and office building is in full swing and should be completed by August. With these or- ders and capacity expansions, ETW Energietechnik GmbH can count itself among the companies in the energy sector that are even creating new jobs in these difficult times.

Reliability and economy - The advantages of the ETW SmartCycle® PSA gas upgrading process at a glance:

• 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

• Adsorbent service life of more than 15 years

• No chemical and biological risks as the process is completely dry

• No waste water and no waste.