Biodiesel, which is a renewable and environmentally friendly fuel, has been studied widely to help remedy increasing environmental problems. One of the key processes of biodiesel production is oil extraction from oils...Biodiesel, which is a renewable and environmentally friendly fuel, has been studied widely to help remedy increasing environmental problems. One of the key processes of biodiesel production is oil extraction from oilseed materials. Switchable solvents can reversibly change from molecular to ionic solvents under atmospheric CO_2,and can be used for oil extraction. N, N-dimethylcyclohexylamine(DMCHA), a switchable solvent, was used to extract oil from Jatropha curcas L. oil seeds to produce biodiesel. The appropriate extraction conditions were:1:2 ratio of seed mass to DMCHA volume, 0.3–1 mm particle size, 200 r·min-1agitation speed, 60 min extraction time, and 30 °C extraction temperature. The extraction ratio was about 83%. This solvent extracted the oil more efficiently than hexane, and is much less volatile. By bubbling CO_2 under 1 atm and 25 °C for 5 h, the oil was separated, and DMCHA was recovered after releasing CO_2 by bubbling N_2 under 1 atm and 60 °C for 2 h. The residual solvent content in oil was about 1.7%. Selectivity of DMCHA was evaluated by detecting the protein and sugar content in oil. Using the oil with residual solvent to conduct transesterification process, the oil conversion ratio was approximately 99.5%.展开更多
In this study,by means of the experiments for desulfurization of model diesel through oxidative extraction,the changes associated with the rate of desulfurization of diesel and the mechanism for oxidation of sulfides ...In this study,by means of the experiments for desulfurization of model diesel through oxidative extraction,the changes associated with the rate of desulfurization of diesel and the mechanism for oxidation of sulfides in diesel were explored. Through studying the mechanism for oxidation of sulfides and the principle of solvent extraction,the kinetic equation of desulfurization via oxidative extraction were determined. By means of the evaluation of model parameters and curve fitting,the reaction order between organic sulfide and sulfone,the intrinsic oxidation rate constant of organic sulfide and sulfone,and the equilibrium constant between sulfone in model diesel and extractive solvent were determined. The experimental values of the desulfurization rate and the theoretical values of the corresponding model equation had closely demonstrated that the desulfurization reaction rate had high accuracy. And the reaction kinetics could provide an important basis for diesel desulfurization process in the future.展开更多
基金Supported by Doctoral Fund of Ministry of Education of China(20130181130006)the National Natural Science Foundation of China(No.21476150)
文摘Biodiesel, which is a renewable and environmentally friendly fuel, has been studied widely to help remedy increasing environmental problems. One of the key processes of biodiesel production is oil extraction from oilseed materials. Switchable solvents can reversibly change from molecular to ionic solvents under atmospheric CO_2,and can be used for oil extraction. N, N-dimethylcyclohexylamine(DMCHA), a switchable solvent, was used to extract oil from Jatropha curcas L. oil seeds to produce biodiesel. The appropriate extraction conditions were:1:2 ratio of seed mass to DMCHA volume, 0.3–1 mm particle size, 200 r·min-1agitation speed, 60 min extraction time, and 30 °C extraction temperature. The extraction ratio was about 83%. This solvent extracted the oil more efficiently than hexane, and is much less volatile. By bubbling CO_2 under 1 atm and 25 °C for 5 h, the oil was separated, and DMCHA was recovered after releasing CO_2 by bubbling N_2 under 1 atm and 60 °C for 2 h. The residual solvent content in oil was about 1.7%. Selectivity of DMCHA was evaluated by detecting the protein and sugar content in oil. Using the oil with residual solvent to conduct transesterification process, the oil conversion ratio was approximately 99.5%.
文摘In this study,by means of the experiments for desulfurization of model diesel through oxidative extraction,the changes associated with the rate of desulfurization of diesel and the mechanism for oxidation of sulfides in diesel were explored. Through studying the mechanism for oxidation of sulfides and the principle of solvent extraction,the kinetic equation of desulfurization via oxidative extraction were determined. By means of the evaluation of model parameters and curve fitting,the reaction order between organic sulfide and sulfone,the intrinsic oxidation rate constant of organic sulfide and sulfone,and the equilibrium constant between sulfone in model diesel and extractive solvent were determined. The experimental values of the desulfurization rate and the theoretical values of the corresponding model equation had closely demonstrated that the desulfurization reaction rate had high accuracy. And the reaction kinetics could provide an important basis for diesel desulfurization process in the future.
