Preparation Of Biodiesel From The Foot Oil Of Tea

Biodiesel was prepared with the foot oil of tea as the raw material under the action of the catalyst for the problem of expensive raw materials and it combined with the policy of "national tea industry development plan(2009- 2020)". The optimum concentration of potassium hydroxide was studied during the process of alkali refining. Meanwhile, thebiodiesel was prepared with the pretreated foot oil of tea as the raw material under the catalysis of methanol sodium. The effect of molar ratio of oil to methanol, reaction temperature, reaction time, catalyst amount and string rate on the process was invested by using the yield of biodiesel as the evaluation index. The results showed that yield of biodiesel got a good balance when the molar ratio of oil to methanol was 6:1, reaction temperature was 60℃,reaction time was 90 min, catalyst amount was 1.1% and string rate was 800r/min.A new kind of solid catalyst was prepared to overcome the shortcomings of methanol sodium which was not easy to separate and recover in the homogeneous reaction. The solid catalyst was prepared with sepiolite as carrier and potassium carbonate as dipping solution by the means of impregnation method based on the principle of environmental protection, low-cost. The loading amount of catalyst in different concentrations of potassium carbonateand the effect of the loading amount of catalyst on the conversion rate of biodiesel were studied respectively. Meanwhile, the structure of the solid catalyst was characterized. The results showed that the loading amount of catalyst increased first and then tend to flatten with the increase of the concentration of potassium carbonate, the loading amount of catalyst achieved maximum(1.427 g / 6g) when the concentration of potassium carbonate was 50wt%.The yield of biodiesel was also increased with the increase of the loading amount of catalyst, when the loading of sepiolite was 1.427 g / 6g, the conversion of biodiesel was 64.3%.In order to further increase the loading amount of potassium carbonate, sulfuric acid was used to the acidification of sepiolite to increase the specific surface area. The solid catalyst was prepared with potassium carbonate solution as the dipping solution and sepiolite after the acidification as a carrier. BET, SEM-EDS and XRD were used to characterize and analyze the structure of solid catalyst before and after the acidification of sulfuric acid. The results show that the specific surface area of sepiolite increased significantly after acidification of sulfuric acid, the loading amount of potassium carbonate and the conversion rate of biodiesel also both increased significantly. The optimum conditions of acidification and the preparation of biodiesel were invested. The results show that the optimal conditions for acidification: the concentration of potassium carbonate was 50%, the optimal concentration of sulfuric acid used for acidification was 20%, the temperature of acidification was 87 ℃; the optimum conditions for the preparation of biodiesel: the methanol to oil ratio was 8: 1, the reaction temperature was 65 ℃, reaction time was 10 h, the amount of catalyst was 5wt%.