Thermal energy of plant biomass, its components, and secondary biofuels

The main purpose of this article was to study the content of thermal energy (Q)and energy density (ED) in various biomass types, in the biomass components such as cellulose, hemicelluloses, lignin, and some other substances, as well as, in biomass-based secondary biofuels, solid (bio-char), liquid (bio-alcohols, bio-gasoline, biodiesel fuels), and gaseous (bio-hydrogen, bio-methane, syngas). For this purpose, methods of chemical thermodynamics were used. It was found that the increased content of lignin, lipids, resins, and waxes in the biomass contributes to its high Q value, while moisture and ash reduce the Q value of the biomass. A method of additive contributions of thermal energies of main biomass components is proposed to calculate the Q value of the biomass sample. Considerable attention is also paid to studying thermal energy content in cellulose derivatives, and secondary solid, liquid, and gaseous biofuels. The Q and ED values of biochar obtained from biomass are significantly higher than those of the initial biomass. Of the various liquid fuels, bio-gasoline synthesized from synthesis gas by the Fischer-Tropsch method has the largest amount values of Q and ED. Among the various biogases, bio-hydrogen has no competitors because of its enormous thermal energy content. However, if the value of energy density is calculated, then bio-methane comes out on top.