Progress of the applications of bio-oil

Bio-oil is considered a renewable feedstock for the production of energy, fuels, chemicals and carbon materials. These specifically include the direct combustion of bio-oil as a boiler fuel, the production of biofuel from bio-oil via hydrotreatment, or the production of value-added chemicals via separation and acid-catalysis/hydrogenation or the conversion of bio-oil to carbon materials via polymerisation/cracking. So far, considerable efforts have been made to develop feasible method for utilizing bio-oil. However, it remains a challenge to find a suitable outlet for the commercial application of bio-oil. The conversion of bio-oil into the useful products has been the focus of numerous studies. Therefore, the review of the progress of this area is of importance for providing the necessary information for assessing the feasibility of the varied process for the application of bio-oil in a comparative manner. This work reviewed the progress of bio-oil as the feedstock for the use as boiler, heavy-duty engine fuel, or the use as the feedstock for the production biofuel, hydrogen, chemicals, carbonaceous materials, binder for electrode and asphalt, pesticide and fertilizer, polyurethane foam and plastics. In addition, the major issues associated with the application of bio-oil as well as the techno-economic aspects of each application were analysed as well. Suggestions were given for the future developments in each application. The analysis indicated that majority of these technologies are mainly in the initial stages of developments. Either cost or the technical issues are the major barrier for the commercial application of bio-oil in large scale.