Catalytic Processes and Catalyst Development in Biorefining
The great potential of the catalytic biorefinery makes it practical for the substitution of renewable plant biomass for fossil feedstocks in new and traditional technologies. The scientific and commercial interest in the biorefinery concept has grown rapidly in the XXI century. The present Chapter is an overview of prospective catalysts and catalytic processes for valorization of plant biomass. There are three parts in the Chapter. Part 1 is a brief description of the composition and properties of the three most important components of plant biomass (cellulose, hemicelluloses and lignin). Part 2 gives insights into thermochemical and liquid-phase (more details are given in Chapter 3) processes for lignocellulose decomposition to produce bio-products (biochar, bio-oil and biogas) and platform molecules that are capable of replacing fossil raw materials (coal, oil and natural gas). Special emphasis is placed on pyrolysis, liquefaction and gasification, which transform lignocellulose into bio-oil and synthesis gas, as the methods for thermochemical depolymerization. Liquid-phase depolymerization of polysaccharides combined with dehydration, reduction, hydrogenolysis and oxidation in one-pot processes, as well as aqueous-phase reforming and biomass delignification, are discussed. Part 3 describes transformations of the main biomass-derived semi-products (syngas, bio-oil, sugars, furfurals and levulinic acid) to fuels or chemicals. Ready-to-use and promising methods for catalytic and biotechnological upgrading of bio-products to fuels and chemicals are considered.