Conventional esterification of fats/waste oils with high free fatty acids is time-consuming and energy intensive. In this study, a novel liquid-phase plasma discharge (LPPD) reactor was designed and evaluated for rapid esterification to convert oleic acid to biodiesel. Three LPPD operating parameters, i.e., feeding flowrate, methanol to oleic acid molar ratio (M/O), and sulfuric acid to oleic acid weight ratio (A/O), were all evaluated at five levels (1.2, 1.8, 2.4, 3.0, and 3.6 ml s⁻¹ for flowrate; 4, 6, 8, 10, and 12 for M/O; and 0, 1, 2, 3, and 4 % w/w for A/O) using a fractional factorial experiment design. For each experiment, three treatment times (2, 6, and 10 min) were also tested. The optimum operating parameters for the LPPD were 2.4 ml s⁻¹ for flowrate, 10 for M/O, and 2.0 % w/w for A/O, respectively, with the maximum conversion rate of 78 %. The power and applied voltage were consumed at 340 W and 2.12 kV during the 2-min treatment. The methyl oleate samples produced in this LPPD process were identified by GC-MS (gas-chromatography mass spectrometry) and FTIR (Fourier transform infrared spectroscopy) to confirm the esterification pathway.

脂肪/废油与高游离脂肪酸的常规酯化既费时又耗能。在这项研究中，设计并评估了新型液相等离子体放电（LPPD）反应器的快速酯化反应，以将油酸转化为生物柴油。进料流量，甲醇与油酸摩尔比（M / O）和硫酸与油酸重量比（A / O）的三个LPPD操作参数均在五个级别（1.2、1.8、2.4、3.0）下进行了评估，流量为3.6 ml s ^-1； M / O为4、6、8、10和12； A / O为0、1、2、3和4％w / w），使用分数阶乘实验设计。对于每个实验，还测试了三个处理时间（2、6和10分钟）。LPPD的最佳操作参数为2.4 ml s ^-1流量，M / O为10，A / O为2.0％w / w，最大转换率为78％。在2分钟的处理过程中，功率和施加的电压在340 W和2.12 kV下消耗。通过GC-MS（气相色谱质谱法）和FTIR（傅立叶变换红外光谱法）鉴定在此LPPD工艺中产生的油酸甲酯样品，以确认酯化途径。