Conversion routes from biomass feedstock

The study summarized in this paper involved the identification of over 1.100 possible missions (specific conversion routes from biomass feedstock to useful fuel and chemical products to end-use markets) prior to the selection of 15 missions for detailed analysis. 

Second-generation biofuel technologies make use of a much wider range of biomass feedstock (e.g., forest residues, biomass waste, wood, woodchips, grasses and short rotation crops, etc.) for the production of ethanol biofuels based on the fermentation of lignocellulosic material, while other routes include thermo-chemical processes such as biomass gasification followed by a transformation from gas to liquid (e.g., synthesis) to obtain synthetic fuels similar to diesel. The conversion processes for these routes have been available for decades, but none of them have yet reached a high scale commercial level. 

The present chapter discusses aspects, known by the authors, of (a) biomass as feedstock, (b) the concept of bio-refinery, (c) thermochemical routes from lignocellulosic biomass to fuels, and (d) the contribution of catalytic technology. The main focus will be on the catalytic conversion of fast pyrolysis oil into fuels with regard to problems encountered currently and the challenges for future research and development. 

This chapter focuses on production of sugars from cellulosic or fibrous biomass feedstocks using conversion routes based on enzymatic hydrolysis. Section 4.2 describes the nature of cellulase and hemicellulase enzyme systems capable of depolymerizing cellulose and hemicellulose to soluble sugars, and reviews the prominent concepts of enzyme synergy and biomass recalcitrance. Performance of enzymatic hydrolysis under anticipated real-world processing conditions involving... 

Figure 4.3 illustrates different possible conversion routes for the production of ethylene from biomass. One way to produce ethylene from renewable feedstock is catalytic dehydration of bioethanol. In the short term, it is likely that bioethanol dehydration for the production of ethylene will be established in regions with cheap access to bioethanol, for example, Brazil, where ethanol usage is on the same level as usage of fossil-based fuels (on an energy basis) in the transportation sector. In Europe and the United States, this trend is expected to occur after the commercial introduction of lignocellulosic ethanol (Jones et al., 2010). 

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