Biogas upgrading success

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Upgrading biogas to biomethane success

ETW Energietechnik supplies the biomethane upgrading technology for a 45km biogas gridWith a newly built biogas pipeline, the association Biogaspartner Bitburg in Germany will be bundling the raw biogas supplies of up to 48 biogas plants from the region. The 45km-long pipeline began transporting the renewable energy source to a central upgrading plant at the Bitburg commercial, service and leisure centre area Flugplatz Bitburg in May 2020. There it is refined to biomethane (a natural gas equivalent renewable alternative) and fed into the gas grid.

With this pipeline, the shareholders, SWT Stadtwerke Trier, the private waste management 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 10,000m3 of raw biogas per hour. Since May 2020, an initial seven plants have been sending 1,800m3 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 specialist ETW Energietechnik in Moers. It is based on the established ETW SmartCycle PSA technology, which was developed by ETW’s own design team. “In the module, up to about 1,800m3 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 at ETW Energietechnik. 

Biogas upgrading is used to refine biogas with a composition of about 50% 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. 

Dynamic adaptation during the biogas upgrading process

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 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 that not only the treatment plant can be operated but also the already connected and future biogas plants can be monitored,” says 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.” 

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 1,920 Nm3/h raw biogas and is the first biomethane project for ETW outside Europe. 

In addition, ETW is 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 therefore gradually establishing itself as a supplier of industrial biomethane plants. 

Not least for this reason, the company is currently in the process of doubling its production capacity at its headquarters in Moers. With these orders and capacity expansions, ETW Energietechnik can count itself among the companies in the energy sector that are even creating new jobs in these difficult times.  

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