Economic and environmental assessment of catalytic and thermal pyrolysis routes for fuel production from lignocellulosic biomass

Abstract

Meeting the transport needs of a growing world population makes it imperative to develop renewable and sustainable routes to production of liquid fuels. With a market-driven economic structure and pressing environmental issues, it is essential that these new routes provide environmental benefits while being economically viable. Conversion of second-generation lignocellulosic biomass resources to fuels via pyrolysis represents an important technological route. In this article, we report comparative assessment of the economic and lifecycle environmental aspects for catalytic and thermal pyrolysis. The goal of this assessment is two-fold: one is to understand the potential of this conversion route via the catalytic and thermal processes and second is to provide feedback for further development of catalysts for various stages of this conversion. The complete assessment is interdisciplinary in nature and connects the laboratory experiments with contextual sustainability assessment. Three catalytic and one thermal pyrolysis processes are analyzed using this assessment approach. Subject to the model choices and data inputs, the results, which consider quality of the oil product, show that biofuels produced using catalytic and thermal routes are rather expensive compared to gasoline. But at the same time, they provide significant greenhouse gas emission savings and can lead to lower CO2 abatement costs compared to the first-generation ethanol that is used currently. With one of the product scenarios of hydrotreated (HT) oil, the abatements costs are estimated to be 51% of those associated with first-generation ethanol. Additional product scenarios with developments in catalysts show potential to further reduce abatement costs significantly to below 100 EUR per metric tonne of CO2 equivalents. Using scenario analysis, the results help us to understand specific areas for development of novel catalysts. At the same time, the results demonstrate the trade-offs associated with the variety and complexity of technical factors associated with the pyrolysis routes. The study highlights the challenges and the promises of catalytic and thermal pyrolysis for production of high-quality biofuels produced via a sustainable production route.