BioH2Ref

BioH2Ref: Decentralized hydrogen production of biogas through steam reforming

Federal Ministry of Economics and Climate Protection (BMWK) , 1 January 2022 to 31 December 2024

Project description

The project deals with the development of an innovative process for the production of hydrogen from renewable energies. The main goal is to generate sustainable energy from biological waste materials. Currently, decentralized electricity and heat production in combined heat and power units (CHP) accounts for 90% of the german market for biogas plants. However, the efficiency there is only 40%. For the hydrogen plant, which uses the principle of steam reforming, an efficiency of over 60% was determined by comparison. The pilot plant has already shown that this can be increased even further through various measures. The project is scheduled to run for three years and is funded by the BMWK. The following project partners are involved in the project:

The standard values for the reduction of greenhouse gas emissions range from 20 % for pure manure systems to 25% for systems with 40% maize input and open digestate storage without waste gas incineration. These high greenhouse gas reduction potentials are due to the fact that the methane emissions associated with animal husbandry are reduced. In this way, 20 million tons of GHG emissions are already saved with the current biogas plant stock in Germany. Promoting decentralized hydrogen upgrading plants from biogas would therefore have a major impact on GHG reduction in the energy sector in the future.

In this project, a container unit for hydrogen treatment was set up at the project partner’s farm and then operated in pilot construction. The container unit consists of a steam reformer (50 Nm³H₂/h) including a burner to provide the process heat, a water-gas shift reactor, a water treatment unit, cooling units and the pressure swing adsorption for the final separation of the hydrogen. The process flow diagram for hydrogen treatment is shown in Figure 1:

Process flow diagram of hydrogen production

Part of the biogas is burned in a highly efficient burner to provide process heat. A biogas volume flow of approx. 30 Nm³/h is converted into a hydrogen-containing gas mixture together with purified water in the reformer with the connected water-gas shift reaction. The hydrogen is finally separated by pressure swing adsorption (PSA). The tail gas has a residual calorific value and is fed back into the combustion process to optimize the energy balance. The resulting waste heat is fed into the biogas process to heat the substrate to the fermentation temperature in order to optimize the overall plant efficiency.

Project goals

The main objective of the project is the production of market-ready green hydrogen from biogas in the pilot plant specially developed for this purpose. Using steam reforming as the process basis and with the help of the project partners, the highest possible purity level should be achieved for the hydrogen treatment process. The hydrogen produced is to be integrated into existing transportation systems (e.g. hydrogen filling stations for cars and trucks) as planned and thus enter into commercial distribution. In addition, the pilot plant (Figure 2) will serve as a model for further plants to be built at other locations in the future in order to produce hydrogen decentrally using the same principle.