Techno-economic assessment of an integrated biorefinery producing bio-oil, ethanol, and hydrogen

Abstract

The production of multiple products, in an integrated manner, encourages the full valorization of biomass feedstock and reduces waste streams. This may improve the economic outlook of the biorefinery and provide a hedge for investors. There is limited understanding of the techno-economics of an integrated, multi-product biorefinery. This study addresses this gap. In this study, we investigated an integrated, multi-product biorefinery. In addition to bio-oil, the valuable products ethanol and hydrogen are produced from fast pyrolysis by-products. We developed process models for bio-oil, ethanol, and hydrogen production from spruce woodchips in an integrated syngas fermentation and fast pyrolysis plant. Six scenarios set against a base fast pyrolysis plant were investigated, and the economic performance of each scenario was evaluated based on the rate of return. The scenarios differ in terms of the use of the non-condensable gases and the type of external fuel used for process heat. In every scenario, biochar is used for ethanol production and bio-oil is assumed to be a final product. The base case had a return rate of 7.0%, while the return rate ranged between 7.46 and 13.01% among the six scenarios. The scenario producing hydrogen from hydrogen-rich non-condensable gases and ethanol from biochar was the most profitable. The profitability was found to be most sensitive to product prices, capital cost, and feedstock cost. The study’s results show that an integrated, multi-product approach to biorefining has the potential to improve the economics of biorefineries and biofuel production.