Farm-based lignocellulosic biorefinery

Problem statement

The biorefinery approach uses farm residues to produce bio-materials and energy, without competing with food production. The focus is the production of the platform chemical hydroxymethylfurfural for biobased plastics.

Executive summary

This is a pilot research project that involves the creation of a biorefinery plant at the university’s “Unterer Lindenhof” research station.
The vision is to design a small-scale plant for farm use that uses both biogenic plant residues and agricultural by-products to produce a wide range of raw materials and energy sources, without competing with food production.

Technology description

In the center of the biorefinery, there is an existing biogas plant. The whole concept is demonstrated in the research station "Lindenhöfe" of the University of Hohenheim. The mass flows of the research-station, which is a farm, are used as input of the biorefinery.
For the utilization of agricultural residues via the production of the bio based basic chemical 5-hydroxymethylfurfural (HMF for short) a pilot plant was built up. In this process, the carbohydrates in the (residual) biomass react in aqueous medium under pressure and elevated temperature (hydrothermal conditions) to form HMF. The different chemical-functional groups of this reactive molecule allow a variety of chemical modifications and make HMF a versatile renewable basic building block. For this reason, it is also one of the 12 most important bio based platform chemicals of the future. For example, oxidation of 5-HMF produces the platform chemical FDCA, which can replace petrochemical-based terephthalic acid (TA) in all its polymer applications. Currently, one of the best studied polymer applications is polyethylene furanoate (PEF), a high-performance bio-based polymer with excellent physicochemical properties compared to PET. This leads to lower energy requirement in further processing and thus the environmental impact.
In addition, PEF has higher gas barriers by a factor of 10. The structural similarity to PET allows, in addition to single-grade recycling, the mixing with PET.

Market deployment considerations

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Environmental considerations

In the case of PEF, a saving of approx. 4.6 kg of CO2 per kg of plastic is possible.