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Phytotechnology with Biomass Production
10.1 Introduction
The gradual depletion of nonrenewable fossil fuels and environmental deterioration due to the growing demand for energy sources and concern over
greenhouse gas emissions have attracted considerable attention to exploring renewable and sustainable biofuels and supporting sustainable economic development (Arnoult & Brancourt-Hulmel, 2015). Lignocellulosic
biomass, mainly composed of carbohydrate polymers (cellulose and hemicellulose) and an aromatic polymer (lignin), is widely identified as a promising alternative with great potential for biofuels production (Ho et al.,
2019; Kim et al., 2016). Biological conversion of lignocellulosic biomass into
ethanol, methane, hydrogen, heat, power, bio-oil, and syngas can reduce
overdependence on petroleum-based fuels and mitigate climatic change
(Brosse et al., 2012; Ge et al., 2016; Ziolkowska, 2014). In particular, bioethanol derived from lignocellulosic biomass has been utilized as a substitutive
transportation biofuel to conventional gasoline (Bailey, 2018; von Blottnitz
& Curran, 2007; Wyman, 2008).
The biomass of the second-generation crops including Miscanthus is processed to energy through distinct conversion routes: thermochemical and
biochemical (Damartzis & Zabaniotou, 2011). The thermochemical route
consists of the pyrolysis and/or gasification and subsequent gas cleaning
and conditioning processes, followed by the Fischer–Tropsch synthesis for
the production of synthetic liquid fuels. The biochemical route involves
the enzymatic transformation of cellulose and hemicellulose to sugars and
subsequent fermentation to bioethanol. The second route, although having
more cost reduction potential due to its most recent development and constant effort for optimization, is less prone to commercialization than the first
alternative. These two main pathways of biomass processing are illustrated
in Figure 10.1.
The differences among the thermochemical processes are determined by
the operation conditions of feed properties, oxidizer (air, oxygen or steam)
amount, temperature, heating rate, and residence time.
10.2 Evaluation of Biomass Suitability for Energy
The key criteria for evaluating the suitability of plants as a raw material for
combustion are the amount of biomass from 1 ha of cultivation, the amount of
heat obtainable per unit weight of biomass, the cost of establishment of plantation, and the content of mineral substances determined as ash. The amount