Study On Preparation Of Biodiesel From Rapeseed Oil Catalyzed By Solid Base Catalyst

As one of the most important clean fuel,biodiesel has drawn more and more attention.Homogeneously catalyzed transesterification is widely used,but this sophisticated method has many drawbacks such as environmental pollution and saponification.Solid base prepared by impregnation can efficiently catalyze transesterification without problems mentioned above.At this work,a novel solid base maken by impregnating K₂CO₃ on Hydrotalcite(HT) was prepared.We also produced biodiesel using the solid base as a catalyst.The main conclusions were as follows:(1) Biodiesel was prepared from rapeseed oil by transesterification with the solid base catalyst of K₂CO₃.The conversion of 95.9%was achieved using a 9:1 methanol to oil molar ratio at 60℃for 20 minutes and 1 wt%catalyst.(2) K₂CO₃/HT catalyst was prepared by impregnation method and the condition of preparing catalyst were the amount of K₂CO₃ loaded 20%,blending temperature 80℃,calcination temperature 600℃and calcination time 6h.The prepared catalyst was characterized by X-ray diffraction(XRD),thermogravimetry (TG),scanning electron microscope(SEM).The results indicated under calcination at 600℃,K₂CO₃ interacted with HT and formed new stable crystalline phase.(3) The effect of reaction time,catalyst dose,methanol to oil ratio, temperature on biodiesel yield was investigated.The conversion of 96.9%was achieved using a 12:1 methanol to oil molar ratio at 60℃for 6 h and 4wt%catalyst.(4) Through regression rotating orthogonal combination analysis,the optimum condition was molar ratio of oil was 13.5:1,usage amount of catalyst was 5%,reaction temperature was 65℃and reaction duration was 65min.Conversion of fatty acid methyl ester was up to 99%and true test value of 98.3%.A mathematical regression model was established by Matlab.The error is less than 5%between model value and experimental value.(5) K₂CO₃/HT can be reused in transesterification under the same reaction condition.The results show that at the fifth time of reusing catalyst,Conversion of fatty acid methyl ester is still more than 80%.