Pyrolysis of biomass with sulfated/zirconia-titania
thesisposted on 2022-08-29, 08:18 authored by Yichen Liu
The project carried out in the past four years has focused on the area of biomass pyrolysis for the production of bio-oil, and the upgrading of bio-oil. In the beginning of the work, mixed metal oxide catalysts – sulfated/ zirconia-titania with different ZrO2 loading amounts were studied. One of the major parts of this work was to investigate the relationship between catalyst activity and catalyst properties, including surface area and surface acidity. Model reaction between acetic acid and ethanol was also carried out to test the catalyst activity. The investigation has shown the highest acetic acid conversion was obtained by using 60 wt% SO4 2-/ ZrO2-TiO2. Furthermore, SO4 2-/ ZrO2- TiO2 was applied in bio-oil esterification. The result showed the bio-oil properties have been improved greatly. Following on from this work, biomass hydro-pyrolysis and catalytic cracking was studied since it is a possible approach for high grade bio-oil production thus enhancing the level of biomass conversion. 60 wt% SO4 2-/ ZrO2-TiO2 was used in this study, as well as different H2 pressures ranging from ambient pressure to 20 bar. The result has shown the hydro-pyrolysis had many advantages over the conventional pyrolysis since a large amount of oxygen was removed from bio-oil in the form of water and COx. This would not only enhance the stability but also the high heating value of bio-oil. Moreover, hydrolysis residue and pure lignin were also tested as feedstock. The result showed the hydrolysis has potential to become the resource for phenolics production. Finally, ZrO2-modified TiO2 nanorod composites were synthesized using the hydrothermal synthesis approach. The synthesized materials were characterized by XRD, SEM, TEM, Raman, IR, and XPS. It was found that both sizes and morphologies of ZrO2 particles significantly depended on the reaction temperatures and hydrothermal synthesis time. The highest conversion of levulinic acid to ethyl levulinate, 81.2%, was reached in at 110°C after 2h over a ZrO2-TiO2 nanorod composite. The synthesized composite as the catalyst showed the potential ability for bio-oil upgrading.