Stabilization of pyrolysis oil: Comparison of reactive distillation and reactive chromatography

• Reactive distillation and reactive chromatography can successfully stabilize bio-oil.
• The performance of reactive distillation is hampered by catalyst deactivation.
• Reactive chromatography (RC) does not show noticeable catalyst deactivation.
• The reaction kinetics and adsorption isotherm are determined using the experimental data.
• The proposed model for RC explains the experimental results reasonably well.

The present study, evaluates the applicability of reactive distillation and reactive chromatography for stabilization of bio-oil, obtained from pyrolysis of wood. Bio-oil, along with several oxygenated organic compounds, contains substantial amounts of carboxylic acids (e.g., acetic acid, 5–10%). The presence of acids results in a shorter shelf life of bio-oil, as it catalyzes condensation reactions of furfural-like components leading to an increase in viscosity over a time period. Thus, we investigate the ability of multifunctional reactor for stabilization of bio-oil through esterification of acid with suitable alcohol in the presence of ion-exchange resin catalyst. Reactive distillation is performed at higher a temperature which is dictated by the bubble point of the mixture, reactive chromatography allows one to perform reaction at relatively low temperatures and with lower alcohols. It results in an improvement in the characteristic properties of bio-oil, thereby increasing the shelf life. The main limitation of this approach is that the catalyst used for esterification also catalyzes simultaneous polymerization of furfural-like components which deactivate the catalyst. Deactivation of Amberlyst-15 with ethanol after 20 h of continuous run in a fixed-bed chromatographic-reactor was found to be less compared to RD making RC a promising candidate for this particular application.