OPTIMAL ENERGY OUTPUT OF A LIGNOCELLULOSIC RESIDUAL BASED BIOREFINERY

The aim of this work was to analyse different scenarios for a bioethanol and biogas producing wheat straw biorefinery focusing on the maximal energy output. Wheat straw was steam exploded at different times and temperature conditions. Glucose yields and specific biogas yields were determined via laboratory batch-experiments. Ethanol yield was stated to be 0.4 gEtOH/gglucose. Five different scenarios, including single biogas production of untreated and pretreated wheat straw as well as biogas production of hydrolysed pretreated straw and the combined production of biogas and bioethanol were evaluated. It was shown that single biogas production from pretreated and hydrolysed straw had the highest energy output based on input material, when the energy content of the endproducts methane and ethanol was considered. Process energy needs and energy content of any by-products were not included in the evaluation. Preferable pretreatment conditions differ between biogas and bioethanol production.