Page 265 - Refining Biomass Residues for Sustainable Energy and Bioproducts

234 Refining Biomass Residues for Sustainable Energy and Bioproducts

biomass after sugar extraction can be considered a good candidate for solid biofuels
production (Ivanova et al., 2018).

10.5 Output across the world

Research outputs presented in terms of patents, publications, and products are help-
ful to mankind. Sorghum grain is an important source of food and industrial pro-
ducts (Williams and Rao, 1981). In recent times, various technologies and products
based on sorghum have been patented. Sweet sorghum is a crop where each part of
the plant has an application—its grain can be utilized to make food, feed, and bev-
erages, its stalk can yield sugar, fuel, forage, and fiber for use as mat, hat, building
material, frame material, and barrier, its roots can be utilized to produce the biofuel,
its peduncle is used to make cover, and finally threshed spikes are used to make
broom and pot-scouring brush (Almodares and Hadi, 2009; Anglani, 1998;
Williams and Rao, 1981). Sweet sorghum is one of the most drought-tolerant cereal
crops which reduces the costs on irrigation and other on-farm expenditures (Hattori
et al., 2005). A compilation of patents on sweet sorghum, which can be utilized for
various applications for feed, food, and biofuels, is shown in Table 10.1.

10.6 Techno-economic aspects

Major factors affecting the techno-economic viability of ethanol production using
sweet sorghum are (1) the supply and demand for ethanol, (2) competence of this
biomass as an alternative substrate, and (3) to fulfill the government-mandated etha-
nol blending requirements (Ratnavathi et al., 2016). To understand the ethanol eco-
nomics from sweet sorghum, biofuel production value chain models should be
analyzed—two primary models, centralizing unit (CU) and decentralizing unit
(DCU), wherein the cost of area cultivation, input supply, and bioethanol produc-
tion (Basavaraj et al., 2013; Dar et al., 2018).
The economics of ethanol production using sweet sorghum under both, the CU
and DCU models, were analyzed by Bsavraj et al. In India, Rusni distillery (Medak,
Andhra Pradesh) was the first sweet sorghum based ethanol plant (CU system)
established in 2007. Based on the CU model, cost of raw material, processing, etha-
nol recovery, and ethanol was 9.62, 6.19, 0.72, and 0.35 $/t, respectively. In this
case, average production rate of ethanol was 4.5% and the benefit-to-cost ratio fig-
ured out to 0.01 (Dar et al., 2018). For CU-based model, sweet sorghum is one of
the best alternatives to produce ethanol. Still the ethanol economics favors the sugar
molasses; sorghum biomass has some advantages, such as low water requirement,
short growing period, and low cultivation cost and resolves the issue of “food ver-
sus fuel.” In order to overcome the inadequacies of CU system, same authors have
set up a DCU system at Andhra Pradesh and Maharashtra with the help of local
farmers and ICRISAT (Dar et al., 2018). The process is like this—sorghum stalk is