The Study Of Gas-phase Esterification Of Preparation Of Biodiesel By Two-step Method

In this paper, come up with hydrolysis-gas phase esterification two-step preparation of biodiesel. Grease the hydrolysis reaction of the preparation of mixed fatty acid, provide fuel for esterification reaction of fatty acids.But usually used hydrolysis conversion rate is low, In order to improve the hydrolysis conversion rate, in this paper, the condition of the hydrolysis reaction was investigated, in order to get the optimal hydrolysis reaction conditions. The esterification reaction is one of the main method of preparation of biodiesel, but usually used in esterification process is easy to cause waste of methanol, acid and drop rate is low, this paper proposes the gas phase esterification method, in order to improve the utilization rate of drop rate of acid and methanol. Through the experimental study, get the following conclusion:(1) Based on the current overview of the main raw material for biodiesel production in the world, for a variety of raw materials for biodiesel production have a detailed understanding. And the specific national conditions in China, by analyzing the economic costs, think jatropha curcasl oil as main raw material for biodiesel production in our country is feasible.(2) The hydrolysis reaction, through atmospheric conditions for hydrolysis catalyst type, catalyst dosage and reaction temperature on the hydrolysis reaction, Show that:optimum reaction conditions of atmospheric pressure under the condition of namely to heavy oil10%sulfuric acid as catalyst, rtemperature is100℃, and the influencing factors of hydrolysis conversion rate in the order:hydrolysis catalyst type> catalyst> reaction temperature. Combined with the optimal conditions of the hydrolysis reaction under atmospheric pressure, the pressure under the condition of hydrolysis conversion rate was investigated, investigation results show that:When the pressure of2MPa, hydrolysis conversion rate is highest, can be reached to93.08%, so the pressure of2MPa is pressurized hydrolysis optimum conditions. In the first two steps of the optimal reaction conditions is investigated on the basis of ultrasonic assisted mixing effects on hydrolysis conversion rate, investigation results show that:Ultrasonic assisted mixing when the power is140w, the hydrolysis conversion can reach the highest, is94.68%. Know the ultrasonic power is140w is the optimal reaction condition.We can know, ultrasonic assisted mixing pressurized hydrolysis reaction of optimal conditions on heavy oil10%sulfuric acid as catalyst, Reaction temperature90℃, pressure of2MPa, ultrasonic power is140w, Under the condition of the hydrolysis conversion rate was94.68%.(3) For gas phase esterification reaction, through the single factor experiment investigates the methanol steam flow rate, the esterification reaction temperature, catalyst type, the influence of the catalyst for the esterification were acid. Investigation results show that:With p-toluene sulfonic acid as catalyst is most obvious effects of acid reduction, conversion rate can reach94.68%. By studying the effect of catalyst reaction to drop acid, think with raw material weight fatty acids2%p-toluene sulfonic acid as catalyst is the optimal conditions.By investigating the impact of esterification reaction temperature on conversion rate, get in the temperature105℃, the conversion rate can reach95.27%. Methanol flow rate on the influence of the acid test, get in methanol steam flow rate for3L-min-1when the conversion rate can reach94.52%.Then, using the Design Expert7.1software for gas phase esterification analysis of the optimum reaction conditions are optimized, through the optimization analysis, For gas phase esterification reaction of the optimum reaction conditions for methanol flow velocity of3.10L·min-1, the esterification reaction temperature is106.30℃, catalyst to oil weight of2.17%.Through the gas phase esterification reaction experiment was carried out, the results show that:The gas phase esterification method acid reduction effect is obvious, conversion rate and conversion rate is higher, implement and test in the process of methanol recycle, save the reaction raw material, reduces the production cost, It has very important significance for the actual industrial production.(4) Using the optimal reaction conditions, studied the mixing the fat cow’s impact on the biodiesel conversion, used to simulate the actual industrial production in different acid value oil raw material of biodiesel conversion rate. The results showed that:The biodiesel conversion with mixed fat cow price rises, thus it is known that, the higher the acid value of raw material oil is more suitable for used as a raw material for biodiesel production.