Thermochemical conversion of biomass and upgrading of bio-products to produce fuels and chemicals

The considerable growth in energy demands and limited fossil fuel sources, together with environmental concerns, have forced the study of renewable, green and sustainable energy sources. Biomass and its residues can be transformed into valued chemicals and fuels with several thermal conversion processes, which are combustion, gasification and pyrolysis. Combustion is a chemical process that involves the rapid reaction of substances with oxygen, producing heat. Gasification produces synthesis gas at high temperatures (800–1200 °C) to generate heat and power. Pyrolysis has been applied for many years for charcoal formation, while intermediate and fast pyrolysis processes have become of significant interest in recent years. The reason for this interest is that these processes provide different bio-products (bio-oil, synthesis gas and biochar), which can be applied directly in various applications or as a sustainable energy carrier. The present chapter covers an overview of the fundamentals of slow, intermediate and fast pyrolysis, followed by the properties and applicability of the pyrolysis products. This study also identifies the features and advantages of the thermo-catalytic reforming (TCR) process in comparison with other technologies. This report presents a comprehensive literature review of bio-oil production and upgrading methods. In addition, the most common catalysts and supports for different upgrading methods are introduced. Finally, the current pathways for 2-methylfuran (2-MF) formation and the selection of xylose-rich biomass are discussed.