Golden hydrogen from biogas

22.05.2025

Source: E & M powernews

An advanced process is set to produce CO2-negative hydrogen from biogas and deliver usable carbon as a by-product. Researchers at the TH Köln are working on this.

A research team led by the Cologne University of Applied Sciences (TH Köln) wants to produce hydrogen in future in such a way that CO2 remains permanently bound. The "H2MikroPlas" project uses plasma cracking of biomethane to produce hydrogen and solid carbon - known as carbon black - at the same time. The latter is an important raw material for plastics and in battery technology. The project participants want to further develop an existing laboratory process and prepare it for industrial use.

In the process, the researchers separate hydrogen and carbon by passing biogas through a microwave plasma. "We produce two usable raw materials in the process - that's what sets our method apart from other hydrogen production technologies," emphasizes project leader Prof. Peter Stenzel from the Cologne Institute for Renewable Energy at TH Köln. So far, the researchers have been using natural gas in the laboratory. Now they want to expand the process to include biomethane, which is supplied by biogas plants and landfill sites.

More complex process control required

The challenge: compared to natural gas, biogas brings with it additional impurities - including nitrogen, water vapor and organic by-products. For this reason, the researchers are working on upstream gas treatment and robust process control. "We have to ensure that our plant also works with the fluctuating compositions of landfill gas," explains research assistant Dr. Patrick Beuel. The Bergische Abfallwirtschaftsverband and the municipal waste disposal company "AVEA GmbH & Co. KG" provide the biogas from biowaste to the TH Köln.

The industrial partner "iplas GmbH" is converting the existing microwave reactor so that it can work continuously with processed biogas. The process: the transparent gas flows through the plasma, which separates the hydrogen molecules (H2) from the carbon (C). The carbon then trickles out of the reactor as a black powder - in the form of fine, reactive nanoparticles. On an industrial scale, the project team expects to produce several hundred kilograms of carbon black per day.

Plant technology enables mobile use

The third partner, "ayxesis GmbH", which specializes in plant and process technology, will also develop an automated system that separates the particles, packages them airtight and prepares them for further industrial use. Depending on the quality, companies could use the material as a filler for conductive plastics, batteries or fuel cells, according to TH Köln. Use as a soil conditioner is also possible.

Another partner is the machine and plant manufacturer Brockhaus Lennetal. According to information from Cologne, this company will design the entire plant as a container solution. This would allow the technology to be set up directly at biogas plants or landfills, without the need to build a hall. The TH Köln is the project coordinator and checks the quality of the products produced and accompanies the development and construction phase. It evaluates the CO2 balance and economic efficiency of the process.

Project proposes new hydrogen category

In the established color scheme for hydrogen, the color grey stands for the fossil production of hydrogen, green for the electrolysis of water with electricity from renewable sources and turquoise for production through methane pyrolysis. Production from pyrolysis. Stenzel sees a fourth option in plasma cracking technology: "As we work with biomethane and bind CO2 in solid form, we produce hydrogen with a negative carbon footprint. That's why we call it golden hydrogen."

The "H2MikroPlas - CO2-negative hydrogen from renewable gases using microwave plasma cracking" project will run until March 2028 and is funded by the European Union and the state of North Rhine-Westphalia with around 3.2 million euros via the ERDF/JTF program NRW (Innovation Competition Energie.IN.NRW).

Author: Davina Spohn