Investigation of the effects of different additives on pyrolysis liquid product properties

In this thesis, the effect of aging under different conditions (7 days at room temperature, and 24 and 168 hours at 80 oC), and the addition of chemicals on the characteristics and rheological behavior of olive pomace-based bio-oil were investigated. Bio-oil was produced via slow pyrolysis at 500 oC. Methanol, furfural, and tetrahydronaphthalene were used as the solvent additives at 5, 10, and 15 wt.%. Ultimate analysis, FT-IR, TGA, and GC-MS analyses were conducted on pre- and post-aged samples to analyze the characteristics of bio-oil and a rheometer was used to analyze the rheological behavior of each sample under different shear rates and temperatures. Shear rate ramp was increased from 5 to 580 1/s, and temperature ramp was applied from 20 to 60 oC. Bio-oil was found to be unstable after a certain period under all storage conditions and durations. GC-MS results showed that chemical reactions occur during storage and the additives trigger several chemical reactions between the compounds in the bio-oil. The rheological behavior of bio-oil was found to be Newtonian. Solvent addition to bio-oil improved the dynamic viscosity. The addition of 10% methanol decreased the dynamic viscosity of non-aged bio-oil by 34.54% and after 168 hours of accelerated aging by 33.90% at 40 oC. Among the chemicals used in this study, methanol was found to be the best additive for the long-term stability of bio-oil. As a result, storage temperature, compared to storage duration has a higher effect on the stability of olive pomace-based bio-oil.