BIOSCEN: Modelling Biorefinery Scenarios

Biorefining unit processes were studied in terms of their physicochemical modelling properties and parameters, complemented by surrogate metamodelling and extensive sensitivity analysis. The unit processes included flash condensation of the fast biomass pyrolysis, thermal and enzyme catalysed hydrolysis of lignocellulosic biomass and fermentation of the hydrolysis product to bioethanol and biobutanol. In addition, a flowsheet based mass and energy balance was developed for the bark biorefinery, the key factors of which were then assessed by using the elementary efficiency method for sensitivity analysis. With the results from hydrolysis and fermentation models, a comparison of the greenhouse gas emissions from barley straw based ethanol and butanol was performed. The bark-based biorefinery producing mainly tannin and ethanol proved to be economically challenging. The results also show that biobutanol is in general more demanding (in terms of greenhouse gas emissions) than the production of bioethanol.