Assessment of By-product Valorisation in a Swedish Wheat-Based Biorefinery

Biorefineries are examples of industries striving towards a circular and bio-based economy through valorising natural raw materials to a spectrum of products. This is a resource-efficient process which also decreases overall environmental impact, as the products from a biorefinery can replace fossil-based products such as plastics or fuels. To become even more resource efficient, an optimisation of the by-product use can increase the performance. This study will evaluate different scenarios for the valorisation of stillage coming from a wheat-based biorefinery. The alternatives range from the direct use of the stillage for fodder, fertiliser or incineration to three different biogas production-based scenarios. The biogas scenarios are divided into the production of fuel at a local or distant plant and the alternative of creating heat and power at the local plant. The results show how locally produced biogas for vehicle fuel and fodder usage are the better alternatives regarding greenhouse gas emissions, the finances of the biorefinery, energy balance and nutrient recycling. The results also indicate that biorefineries with several high-value products may receive lower quality by-product flows, and to these, the biogas solutions become more relevant for valorising stillage while improving value and performance for the biorefinery.Biogas Research Center