Thermodynamic Evaluation of Wood Tars’ Oxy-Conversion with the Production of Hydrogen and Synthesis Gas

A thermodynamic evaluation of the modes of oxidative conversion of wood pyrolysis products with the production of hydrogen and synthesis gas is carried out. The modes of air, oxygen, and steam-air conversion of wood pyrolysis products are studied. In the case of air conversion, with an increase of the fuel-air equivalence ratio (φ), the hydrogen concentration increases logarithmically to 29 vol % at φ = 10 and T = 1000 K; however, at φ = 3, the condensed carbon appears in the products. An increase in temperature to 1300 K slightly enhances the hydrogen yield to 33 vol % at φ = 10, and shifts the appearance of soot into richer mixtures at φ = 5. The addition of water vapor leads to an increase in the hydrogen content in the products and a shift in soot formation to φ = 9. Oxygen conversion makes it possible to increase the concentrations of hydrogen and carbon monoxide to 42.1 and 45.5 vol %, respectively, due to the absence of their dilution with nitrogen. The presence of condensed carbon is not a disadvantage of the process and can be considered as a target product, while the amount of carbon dioxide emissions is reduced.