Study On The Liquid Phase In-situ Upgrading Of Bio-oil

With the development of science and technology, the primary sources of energy such as coal and petroleum are in decreasing supply, resulting in the urgent demand for renewable biomass energy. Bio-oil obtained from the fast pyrolysis or liquefaction of biomass has played a very important role in the clean-energy field due to its so many advantages. This promising liquid fuel can be easily stored and transported, directly used for the combustion, further modified to diesel or gasoline and moreover used for extracting commercially valuable chemical products. Nevertheless, the chemical and physical properties of bio-oil are very different from those of traditional hydrocarbon fuel. Its high water content (15～30wt%), high oxygen content, high viscosity, low calorific value, acidity (pH 2.5) and chemically instability greatly hinder the widespread use of it as a kind of hydrocarbon fuel. Therefore, the bio-oil modification research for the acceptability in the fuel market has become the main research hotspot.Crude bio-oil contains a variety of aldehydes and phenols, which cause the bio-oil instability and affect the combustion performance of bio-oil. Therefore, these harmful ingredients are hoped to preferentially get rid of in the process of bio-oil upgrading. This paper focuses on the treatment of aldehydes and phenols in bio-oil.1、In this work, we report a novel means, named liquid phase in-situ hydrodeoxygenation of bio-derived phenol to cyclohexene and cyclohexane over Raney Ni and Nafion/SiO2.In this method, producing hydrogen, hydrogenation and dehydration are merged and coupled owing to the close reaction conditions. The overall specific reaction pathway was studied and influences of Nafion loading, temperature, H2O/MeOH ratio and the quantity of catalysts on the reaction were also researched. In terms of 3g phenol, the suitable operating conditions are drawn as follows:the Nafion loading 13wt%, the reaction temperature 200℃,H2O/MeOH ratio 20mL:15mL, Raney Ni 1g, Nafion/SiO20.3g. The conversion rate of phenol and the total yield of cyclohexene and cyclohexane can reach respectively 100% and 87%.2、While most researchers focus on deoxidation of crude bio-oils to reduce the content of oxygen, this paper proposed another approach as to convert chemically unstable and corrosive oxygenated components into stable and flammable oxygenated compounds. In this work, we report a novel means, named liquid phase in-situ hydrogenation of bio-derived phenols and aldehydes to stable and flammable oxygenated compounds over Raney Ni. In terms of 3g phenol,2g furfural and 1g vanillin, the suitable operating conditions are drawn as follows:the the reaction temperature 220℃, H2O/MeOH ratio 30mL:35mL, Raney Ni 2.5g. The conversion rate of phenol, furfural and vanillin can reach respectively 96.2%,97.6% and 97.5%.The whole reaction system is performed in the liquid phase using in situ hydrogen produced from methanol aqueous-phase reforming, not requiring an external source of hydrogen. The operating conditions are gentle, and the cost is considerably reduced.