甘油酯化反应动力学研究

甘油酯化是高酸值油脂降酸值的有效方法,可用于生物柴油的制备。采用大豆油与油酸的混合物为模型化合物,考察了反应温度对甘油酯化产物分布的影响,建立了甘油酯化二级反应动力学模型,并关联出相关反应的动力学参数速率常数k和反应活化能Ea;通过该模型预测了反应温度、甘油与游离脂肪酸摩尔比和原料油酸值对降酸效果的影响。结果表明:模型值与实验值有较好的一致性;降酸反应对反应温度有较高的依赖性,反应温度越高、甘油与游离脂肪酸摩尔比越大及原料油初始酸值越高,降酸速率越快,降酸反应越彻底。研究结果将有助于揭示甘油酯化反应机理,为甘油酯化反应器的设计提供依据。

Kinetics of glycerol esterification reaction

Glycerol esterification is an effective method to reduce the acid value of acidic oil, which can be used for biodiesel production. A mixture of soybean oil and oleic acid was used as the model compound. The effect of reaction temperature on glycerol esterified product distribution was examined. Kinetic parameters, including reaction rate constant k and activation energy E_a, of all the reactions involved in glycerol esterification process were determined using the second-order reaction kinetics model. The effects of reaction temperature, molar ratio of glycerol to free fatty acid, and acid value of feedstock on acid value reduction were predicted based on the model. The results showed that the model values were in good agreement with the experimental values. The reduction of acid value was highly dependent on the reaction temperature. The higher acid value reduction rate and lower final acid value were observed at higher reaction temperature, higher molar ratio of glycerol to free fatty acid and higher initial acid value of feedstock. The research results were helpful to reveal the mechanism of glycerol esterification reaction and design of glycerol esterification reactor.