Study On The Application Of Nanometer Lanthanum - Based Catalyst In Biodiesel

With the continuous consumption of fossil fuels, biodiesel as a sustainable and green energy has gaind worldwide attention. Not much land and lots of people in our country make it impossible to use edible oil for biodiesel production. Therefore, producing biodiesel from reasonable non-edible oil is selected. In the production process of biodiesel, heterogeneous base catalysts has become the research hot because of the fast reaction rate. And nano heterogeneous base catalysts can improve its catalytic activity more. However, the general base catalyst has no resistance to FFA. Therefore, this paper is design to choose reasonable raw materials and prepare nano heterogeneous base catalysts which has an improved tolerance to FFA, mainly carried out the following tasks:(1) Selected Cornus controversa Hemsl.(CCH) as raw materials for evaluation and analysis. Determine the physical and chemical properties and the fatty acid composition of oil seeds. Compared with Jatropha curcas L.(JC) which is our group’s previous work. The results showed that the oil content of CCH is low, iodine value and ployunsaturated fatty acids content of CCH oil is high. JC possesses the high oil content, suitab le iodine value and saponification value, suitable content of monounsaturated fatty acids and polyunsaturated fatty acids. Therefore, JC is suitable as a raw materials for biodiesel production and CCH is not suitable.(2) A comparative study on the activity of La2O3 and two kinds of nano La2O3 catalysts prepared by sonochemical(nano La2O3-S) and hydrothermal(nano La2O3-H) method in the transesterification of refined Jatropha curcas L. oil(aicd value: 0.82 mg KOH/g) with methanol to produce biodiesel was carried out. These catalysts were characterized by XRD, CO2-TPD, etc. The results showed that the activity of nano La2O3 is higher than La2O3 and the higher activity of nano La2O3 is ascribed to their higher base strength, larger base amount and lar ger BET surface areas. nano La2O3-H and nano La2O3-S almost have the same activity. Considering the preparation time of nano La2O3-S is short and the preparation process of nano La2O3-S is simple, selected nano La2O3-S as an optimum catalyst for optimization of transesteri?cation reaction condition. Under optimal conditions 180 oC, 120 min, 10 wt.%, and 28:1 methanol/oil molar ratio, the FAME content obtained 97.6%. In order to investigate the performance of acid resistance of the catalys, increase oil acid value to 16.66 mg KOH/g, the FAME content obtained 85.2%. Indicating that nano La2O3-S showed a remarkable tolerance to FFA. But the reaction conditions is harsh, requiring high temperature and pressure.(3) Given the results of the above nano preparation methods and harsh reaction conditons, a comparative study on the activity of different molar ratio of Ca/La mixed metal oxide catalysts which introduced CaO to La2O3 prepared by sonochemical method in the transesterification of raw JCO(aicd value: 9.80 mg KOH/g) with methanol to produce biodiesel was carried out. These catalysts were characterized by XRD, CO2-TPD, etc. The results showed that nano Ca/La 3:1 has the highest activity. The optimal reaction conditions is 65 oC, 125.55 min, 8 wt.% and 21.64:1 methanol/oil molar ratio through calculation of response surface methodology, the theory value of FAME content is 90.5% and the actual value of FAME content is 92.7%. Indicating that nano Ca/La 3:1 can catalyze raw oil(aicd value: 9.80 mg KOH/g) under moderate condition.(4) Given the results of part III, and the property of SrO and La2O3 is similar. A comparative study on the activity of Sr/La(I) catalyst prepared by impregnation method in the transesterification of JCO with methanol to produce biodiesel was carried out. These catalysts were characterized by XRD and CO2-TPD. The results showed that 24 mmol SrO/g nano La2O3-S has the highest activity. The optimal reaction conditions is 20:1 methanol/oil molar ratio, 7 wt.% and 120 min through analysis of orthogonal test. Under this conditions, the FAME content is 94.5%. Indicating that 24 mmol SrO/g nano La2O3-S can catalyze raw oil(aicd value: 9.80 mg KOH/g) under moderate condition.