A comparative thermo-chemical characterization of oilseed, millet and pulse stem biomass for bioethanol production

Abstract

Various thermochemical and biochemical processes are resorted to transform agri-wastes into diverse green fuels. Current investigation encompassed three different types of biomass viz., gingelly, kodo millet and horse grams, whose desirability as biofuel feedstock have been largely unexplored till date. The existence of significant amount of cellulose (38.07 %), volatiles (75.19 %), calorific value (avg. 16.98 MJ/kg) in the gingelly biomass, demonstrates the effectiveness of the concerned biomass for utilization as feedstock in diverse industrial applications. The mean estimates of Eα were lower for kodo millet (approx. 150 kJ/mole), followed by gingelly (approx. 178 kJ/mole) and horse gram (approx. 180 kJ/mole). The mean estimates of ΔHα were 174.81 (FWO), 170.22 (KAS), 169.17 (S) and 170.40 (T) kJ/mol for the gingelly biomass. The mean estimates of ΔHα were 147.83 (FWO), 148.81 (KAS), 147.93 (S) and 149.04 (T) kJ/mol for kodo millet biomass, while for horse gram biomass, mean estimates of ΔHα were 178.91 (FWO), 169.61 (KAS), 168.56 (S) and 168.81 (T) kJ/mol. The minor difference of 3–4 kJ/mole between Aα and Hα, signifies the viability of the thermal disintegration process. From master plot, it's evident that the experimental curve intersects multiple theoretical curves, highlighting the intricate characteristics of the thermal disintegration process. The overall ethanol recovery was highest in gingelly as compared to both the biomasses. Gingelly biomass yielded an ethanol titer of 24.8 g/L after 24 h, resulting in a volumetric ethanol productivity of 1.03 g/L/h and an ethanol yield of 0.36 g/g.

Keywords

• Agri-wastes
• Feedstock
• TGA
• Spectroscopy
• ICP-OES
• Bioethanol