对甲苯磺酸加压催化高酸值地沟油连续甲酯化的研究

Continuous methyl esterification of high acid value swill-cooked dirty oil catalyzed by p-toluene sulphonic acid under pressure

以高酸值地沟油为原料,提出了一种对甲苯磺酸催化、加压下连续甲酯化反应的技术。采用单因素实验和正交实验研究了不同工艺条件对甲酯化效果的影响。结果表明,甲酯化的最佳工艺条件为:醇油摩尔比5∶1,反应压力0.8 MPa,催化剂用量0.5%(以地沟油质量计),反应时间25min。在最佳工艺条件下,地沟油酸值(KOH)可从120 mg/g降至1.78 mg/g,酯化率可达98.5%,满足下一步碱催化酯交换制备生物柴油的技术要求。

A continuous methyl esterification technology of high acid value swill-cooked dirty oil catalyzed by p-toluene sulphonic acid under pressure was proposed.The effects of process conditions on methyl esterification effect were studied by single factor experiment and orthogonal experiment.The results showed that the optimal conditions of methyl esterification were obtained as follows：molar ratio of methanol to oil 5∶ 1,reaction pressure 0.8 MPa,catalyst dosage 0.5 % （based on the mass of swill-cooked dirty oil）,reaction time 25 min.Under these conditions,the acid value of swill-cooked dirty oil could be reduced from 120 mgKOH/g to 1.78 mgKOH/g,and the esterification rate reached 98.5%,which satisfied the technical requirements of alkali catalyzed transesterification for biodiesel production.