Catalysis for renewable energy and chemicals, the thermal conversion of biomass

The production of energy from fossil fuels gives rise to the emission of CO2, NO, and SO2. The amounts of these compounds formed during the production of energy from renewables such as wind, sun and biomass are less than those in case of fossil fuels. Therefore, research and development is carried out for the application of renewables now and in the near future. This chapter focuses on the application of biomass, and more specific on the use of catalysts for the conversion technologies of biomass. Promising technologies, which are in a demonstration phase, are pyrolysis, gasification and hydrothermal upgrading. The products from these types of conversion technologies are: gas, fuel oil or bio-oil transport fuels and chemicals for the food and chemical industry. The production of hydrocarbons is a major objective of most bio-oil upgrading research. Flash and fast pyrolysis are techniques combining high healing rates and short reaction times. Rapid quenching preserves valuable products. Most of the technologies are studied on lab-scale or pilot-scale. For a number of conversion routes catalysts are applied. Char formation and coke deposition are major problems in upgrading of pyrolysis oils. Coke deposition deactivates the catalyst and has to be avoided or minimised. Pyrolysis oils are highly oxygenated, viscous, corrosive, relatively unstable and very complex. However, catalytic upgrading may produce a high valuable chemical feedstock. Oxygen in the oxygenated compounds is, therefore, converted to CO and CO2 rather than H2O to preserve hydrogen for hydrocarbon reactions. This paper discusses the use of catalysts in the field of thermal conversion of biomass.