Catalytic Pyrolysis of Pine Wood Sawdust to Produce Bio-oil: Effect of Temperature and Catalyst Additives

In this work, non-catalytic pyrolysis of Turkish pine (Pinus brutia Ten.) wood sawdust was performed in a fixed-bed reactor at various temperatures to obtain the optimum conditions to achieve a maximum bio-oil yield. The highest yield of bio-oil was obtained about 46 wt% at 550°C for non-catalytic pyrolysis. At the optimum conditions, the effects of different catalyst types (KOH, ZnCl₂, and ZnO) and amount of catalyst (5, 10, 15, and 20 wt%) on the pyrolysis product yields and bio-oil properties were investigated. The presence of catalysts changed the product distribution considerably. Increasing the amount of catalyst led to a decrease in the yield of liquid product, while the gas and char yields increased compared to non-catalytic pyrolysis. The chemical compositions of bio-oil were determined with GC-MS analyses. It was determined that bio-oils contain a large variety of organic compounds, such as furans, aldehydes, ketones, phenols, acids, benzenes, alcohols, alkanes, and polycyclic aromatic hydrocarbons (PAHs). The catalysis by KOH significantly increased the levels of phenols, while it reduced the formation of acids and aldehydes. ZnCl₂ produced bio-oil with high percentages of aldehydes. Moreover, ZnO reduced the proportion of PAH in the bio-oil. These results demonstrated that bio-oils could improve with a catalyst. Therefore, catalyst selection for high bio-oil quality is crucial in industrial applications.