Membrane processes in lignocellulosic biorefineries: Status, potential and challenges

Lignocellulosic biorefineries are a cornerstone in the transition of our largely fossil-based society to a climate-society using renewable raw materials. In first generation of biorefineries the focus was on starch and sugar-based feedstock which lead to a competition with the food supply. In order to avoid this the second generation of biorefineries focus on lignocellulosic feedstocks such as wood biomass and agricultural residuals. Key to the success of lignocellulosic biorefineries is the availability of highly selective and low energy separation technologies to ensure the sustainable production of biofuels and biochemicals on an industrial scale, which makes it a perfect match for membrane technology. The focus of this presentation is thus on the status, potential and challenges of membranes processes in lignocellulosic biorefineries. The first part of this presentation will review the current status of membrane processes in lignocellulosic biorefineries. The focus will be on the different membrane applications with regard to the various lignocellulosic biorefinery concepts using e.g. wood biomass, agricultural residuals or grass as raw materials. This will include membrane applications in the pre-treatment of raw materials, in the fermentation stage as well as in the down-stream processing. The emerging membrane processes such as membrane contactors, forward osmosis and pervaporation and their potential applications in the concept of lignocellulosic biorefineries will be covered in the second part of the presentation.The final part of the presentation will focus on the challenges of membrane processes in lignocellulosic biorefineries with special focus on fouling and cleaning of membranes as well as scale-up and process integration. Overall, the presentation will show the current status of membrane processes in lignocellulosic biorefinery concepts and the research challenges to overcome to use the full potentials of membranes processes in these concepts.