Research On Producing Bio-diesel By Using Waste Food Oil Of Restraunt In Non-homogeneous System

Bio-diesel is becoming an alternative to fossil diesel because it has the characteristics of safety and environmental friendliness. Using highly active solid base catalyst for waste food oil transesterificating to produce bio-diesel in the non-homogeneous system has became an important issue with environmental protection and significance of energy strategy.In this paper, supported solid base catalysts were prepared by incipient impregnation, and were applied to catalytic waste food oil and methanol ester-exchange to synthesis bio-diesel. Two higher activity solid base catalysts were selected: KF/CaO and ZnO/CaO.Through the study the suitable technological conditions for preparing solid base were determined: the optimal loading amount of KF·2H2O was 40wt%, the calcination tempreture was 500℃and the calcination time was 3h. To the catalyst of ZnO/CaO the optimum preparation technique was that Zn(CH3COO)2·2H2O loading mount was 2wt%, the calcination tempreture was 700℃and the calcination time was 3h. Using XRD and IR to characterize the prepared catalysts and the results showed that, the active component would generate a new crystal phase KCaF3 after the KF/CaO roasting under a high temperature, and the enhanced catalytic activity of KF/CaO was closely related to the emergence of the new crystal phase. At the same time, the introduction of KF reduced the probability of the alkaline center inactivating because of acidic gases such as CO2. The introduction of ZnO made diffraction peak of activity components enhanced, impurity peak reduced, so its activity better than KF/CaO catalyst.In addition, the effect of catalyst dosage, reaction temperature, reaction time and alcohol-oil ratio on the waste food oil and methanol transesterification r was investigated. The results showed that under the conditions of reaction temperature at 65℃, catalyst dosage at 4wt% of the KF/CaO, alcohol-oil ratio at 6:1 and the reaction time 3h. The yield of biodiesel reached 97.17%.For the ZnO/CaO the dosage at 3wt%, alcohol-oil ratio at 9:1, the reaction time at 3h, the yield of bio-diesel can be as high as 98.11%.Testing the performance of biodiesel products, the results showed that various indicators reached No.0 biodiesel standards. Qualitative analysis by gas chromatography showed that the main group of biodiesel which synthesis from waste food oil is divided into palmitic acid methyl ester, methyl oleate, methyl linoleate and methyl linen.