Biofuel conversion routes, biomass

FIGURE 12.1 Different physical, chemical and thermochemical conversion routes of biomass to biofuels (adapted from Mohanty et al., 2014). 

There is not only a need but also an urge to use waste biomass resources in the production of biofuels, due to the many envirorunental and economic impacts from the conventional fossil-based transportation fuels. The conversion routes applied to biomass for fuel production widely include thermo-chemical, hydrothermal and biochemical. All the three conversion methods are well-suited to achieve the energy requirements for being ecofriendly processes. However, in the present context both thermochemical and hydro-thermal conversion are foimd effective to produce an energy dense liquid bio-oil that could not only be used as a transportation fuel but also for heat and power generation. 

The biorefinery concept is analogous to the modem petrochemical refinery, which is an integrated system of the production of fuels and other value-added products from the biological conversion of various fractions of biomass at different process conditions. A broader classification of the commercial products obtained by the biochemical conversion route is enlisted in Table 25.1. The demand for biofuels will increase to 180/XX) milUon liters, out of which bioethanol constitutes 73% of the demand (Dutta et al., 2012). The increasing demand for biofuels is mainly... 

Lavoie, J.-M., Marie-Rose, S., Lynch, D., 2013. Non-homogeneous residual feedstocks to biofuels and chemicals via the methanol route. Biomass Conversion and Biorefinery 3(1), 39-44. 

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. 

Both biomethane production paths complement one another in an ideal way. While the thermo-chemical route focuses on solid biofuels e.g. wood, straw) the bio-chemical route uses wet biomass e.g. animal manure, maize silage). The latter will be realized with plant capacities in the one-digit thermal MW-scale and the former in the two- to three-digit MW-scale. The provided product is basically similar and can be used together with natural gas in any mixture. The erection of the biogas and Bio-SNG conversion plants can be planned directly at the established gas grid. 

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