Solid Base Catalyst Waste Oil Biodiesel Production Research

With the reducing of the fossil fuel and the deterioration of ecological environment, biodiesel is preparated by the vegetable oils and animal fats. It is has been paid increasing attention as one of the green and renewable diesel fuel. Biodiesel could have the advantanges of solving energy shortage,environment pollution and reducing the emission of Greenhouse Gas. Now, the degree of industrializatal production is lower. The main reason is that the producing cost is too high. About75%percent cost comes from raw materials. Therefore, there is an important significance to use the cheap resources as raw materials to produce biodiesel.In this work, hogwash oil was used to produce biodiesel by two-steps. First a pre-esterification through no catalyst, and then the oil produce biodiesel by a trans-esterification with methanol under KOH as catalys. the production condition and production process to produce biodiesel were studied. The relative experiments and results are summarized as follow:1. The main physical and chemical indexes of hogwash oil and biodiesel were analysised. The hogwash oil was acid value119.2760mgKOH/g, paroxide value127.8263mol/L, saponification number198.5235mgKOH/g; the biodiesel was acid value0.4783mgKOH/g, the density0.7532g/cm3, saponification number15.8761mgKOH/g, the relative molecular mass847.76, paroxide value3.8931mol/L. The structure of biodiesel using gas chromatography analysis, the results showed that the main components for5kinds of fatty acid methyl ester, according to the peak of order: Methyl palmitate, Methyl stearate, Methyl oleate, Methyl linoleate, Methyl linolenate. Analysising the structure of biodiesel to use the FT-IR. Comparing the indicators of biodiesel with U.S. biodiesel standar, the results showed the hogwash oil can be used as the raw material for preparation of biodiesel.2. In no catalyst conditions, the preparation of biodiesel's reaction kinetics was discussed with the hogwash oil and glycerin as raw material. The acid value of hogwash oil by the reaction of fatty acids and glycerin. Using the orthogonal experiment, the effects of reaction temperature, reaction time and material molar ratio of glycerin to hogwash oil on conversion of the free fatty caids in hogwash oil were studied. Under optimum reaction conditions of temperature465.5K, time8hour and mole ration of glycerin to hogwash oil4. The acid value of hogwash oil reduced to1.4mgKOH/g in these conditions, the conversion rate of the free fatty acid up to98.1%. And factors affecting the strength of the order is molar ration of reaction temperature, renction time and methanol to oil. At the same time we put forward the esterification reaction dynamics model of glycerin the pre-esterification. A kinetics model for the esterification of fatty acids was established, in which activation energy E and pre-exponential factor A were67.194kJ/mol and5.67X103L/(kmol-h), respectively. Verification of the kinetics model shows that it can be described the esterification process.3. Fatty acid methyl esters(biodiesel)were prepared by transesterification of Hogwash oil and anhydrous methanol. The Box-Behnken of response surface methodology(RSM) was used to optimine the conditions for biodiesel production using KOH as an alkaline catalyst. A quadratic polynomial equation was received for biodiesel conversion by multiple regression analysis and verification experiments confirmed the validity of the predicted model. The optimum combination for transesterification was methanol-to-oil molar ratio11.52:1, catalyst amount1.39%, and reaction time62.12min. At this optimum condition, the conversion to biodiesel reached above95.14%, the error of about0.98%is less than5%.