Thermodynamic and physical property estimation of compounds derived from the fast pyrolysis of lignocellulosic materials

The development of biomass pyrolysis oil refineries is a very promising path for the production of biofuels and bioproducts from lignocellulosic materials. Given that bio-oil is a complex mixture of organic compounds, the production of valuable bioproducts may imply the use of different separation processes, such as distillation, selective condensation, crystallization based on melting points, liquid-liquid extraction or adsorption, and/or upgrading treatments, such as catalytic cracking or hydrodeoxygenation. In this context, the main objectives of this work are (1) to propose a simple but representative composition of the bio-oil, which can be used as a bio-oil surrogate, and (2) to determine selected thermodynamic, physical, and molecular properties of the organic compounds included in the bio-oil surrogate using different estimation methods and calculation procedures. These properties are critical temperature, critical pressure, critical volume, normal boiling point, enthalpy of vaporization, vapor pressure curves, normal melting point, enthalpy of fusion, heat capacities of gas, liquid, and solid, gas and liquid standard enthalpy of formation, gas standard Gibbs free energy of formation, Hansen solubility parameters, molecular volume, and molecular diameter. This group of properties has been selected for their possible application in the simulation or design of thermochemical, separation, and upgrading processes. Additionally, the suitability of the estimated thermodynamic properties and the proposed surrogate composition has been assessed by comparing experimental and literature data with the apparent enthalpy of formation of the bio-oil predicted from the weight-averaged contributions of the compounds as well as the heat required for the pyrolysis process at 500 °C.