Novel bio-based products from meadow grass

Problem statement

Displacement of fossil based products with bio-based alternatives, while offering rural diversification opportunities.

Executive summary

The biorefinery processes meadow grass silage into a variety of alternative bio-based products including bio-composites, bio-based insulation material, fertiliser and biogas.

Technology description

Biowert Industrie GmbH operates a green biorefinery in Brensbach in the Odenwald, which consists of a biogas plant with two combined heat and power plants (total 1.4 MWel) and a grass refinement plant. In the grass refinement plant, grass from permanent grassland and arable land is processed into various material products, such as AgriCell (thermal insulation material), AgriPlast (natural fibre-reinforced composite material), AgriFer (fertiliser from fermentation residue), as well as the energy products electricity and heat.
Grass silage is slurried and the cellulose fibres are isolated in a mechanical digestion process and then dried. The "grass juice" is fermented together with food waste in the biogas plant. The biogas is converted into electricity and heat. Heat and electricity cover the plant's own needs, the surplus electricity is fed into the public grid. The fermentation residue is used as fertiliser. The process water recovered from the digestate is used again to slurry the silage.
For the production of AgriPlast, the dried cellulose fibres are mixed with a plastic matrix, such as recycled PP or bio-based plastics, such as PLA, and combined in a modified pellet press to form granules that can be processed by injection moulding or extrusion.

Market deployment considerations

Acceptance for bio-based materials (and possibly higher prices)

Environmental considerations

Circular economy, minimal ressource consumption, biobased, CO2 saving