OptiFlexMethan

Duration: 01.06.2024-30.11.2025

Funding provider: BMBF ‘DATI Sprint’ Funding reference: 03DPS1006

Initial situation:

The energy and resource transition requires new approaches to the production of chemicals, electricity and heat. Traditional methods are reaching their limits, which is why innovative solutions are needed to achieve CO₂-neutral operations in the long term. The increasing demand for sustainable energy requires efficient storage and utilisation options for surplus renewable electricity. Furthermore, even after achieving CO₂ neutrality, additional CO₂ must be removed from the atmosphere and bound in order to lower the global earth temperature again in the long term. Biological methanisation, in which CO₂ and hydrogen are converted to methane, can be used both for energy storage and for the material industrial use of CO₂ as a resource. Methane is already not only an energy source, but also a starting material in the petrochemical industry.

The project:

Microorganisms known as archaea are used in biological methanisation. These feed on hydrogen and carbon dioxide in the absence of air and produce methane at relatively low temperatures (40-120°C). If the hydrogen is produced with an electrolyser, the process can be used to relieve the load on electricity grids through flexible operation: if there is a surplus supply, electricity is consumed in the electrolyser and converted into methane in the tubular reactor. The methane can be used not only to generate electricity or heat, but also as a material in chemical processes.

Since 2019, scientists at FH Aachen have been researching the development of a tubular reactor that can be operated flexibly. The 22-litre tubular reactor achieved a methane production rate of 2.5 litres per litre of reactor volume per day and a methane concentration of 94%. In order for the process to be implemented on an industrial scale, further optimisation and long-term proof of stable, flexible operation, even with a fluctuating hydrogen supply, are required.

Objectives:

In the project, the tubular reactor system from the predecessor project SmartBioFlex will be further optimised and the flexibility tested in the long term. The main objective is to increase the methane production rate by automating and improving the mass transfer of hydrogen from the gas to the liquid phase.

In addition, various flexible operating modes will be used to test the resilience of the system. On the one hand, the start-up times are determined, but also the framework conditions for long-term operation are defined.

Once the project has been successfully completed, it will be scaled up and the principle will be tested on a pilot scale, for example at a biogas plant.