The problem with sourcing inedible feedstock is that a single plant species is not widely available, resulting in low oil yields which are unsustainable for commercial biodiesel production. Thus in this study, two high-FFA oils Madhuca indica (MI) and waste cooking oil (WCO) were tested for suitability as a blend for biodiesel production. Char obtained from carbonization and steam activation of Delonix regia pods and Mesua ferrea linn (MFL) seed shells were doped with KOH and H₂SO₄ for base and acid catalyst development to be used separately. In the two-step conversion process, the oil blend was esterified with methanol and acid catalyst, while esterified oil was transesterified with methanol:2-propanol blend and base catalyst. The parameters optimized for both processes (using L25 Taguchi matrices) were reaction temperature, reaction duration, catalyst concentration, alcohol concentration (methanol or methanol:2-propanol blend), and agitation speed. For esterification, MI:WCO ratio and for transesterification, methanol:2-propanol ratio were also optimized. With 98.27% FFA conversion, 99.05% biodiesel yield was the highest, and both carbonaceous supports showed comparable efficiency as catalyst supports. Obtained kinetic data conforms to pseudo-first order kinetic model, with E_a of 2.172 kJ/mol and 1.219 kJ/mol, with A of 45.61 min⁻¹ and 20.97 min⁻¹ for esterification and transesterification, respectively. With both catalysts showing good reusability, the catalyst preparation costs were only $0.047/L of esterified oil and $0.016/L of biodiesel. Therefore, the established cost-efficient process can be used for producing biodiesel with high yields from compatible oil blends and thus reduce dependency on exclusive feedstock.

采购不可食用原料的问题在于单一植物物种无法广泛获得，导致油产量低，这对于商业生物柴油生产而言是不可持续的。因此，在本研究中，测试了两种高 FFA 油Madhuca indica (MI) 和废食用油 (WCO) 作为生物柴油生产混合物的适用性。Delonix regia pods 和Mesua ferrea linn (MFL) 种子壳的碳化和蒸汽活化获得的炭掺杂了 KOH 和 H ₂ SO ₄用于碱和酸催化剂开发分开使用。在两步转化过程中，油混合物用甲醇和酸催化剂酯化，而酯化油用甲醇：2-丙醇混合物和碱催化剂进行酯交换。为两种工艺优化的参数（使用 L25 田口矩阵）是反应温度、反应持续时间、催化剂浓度、醇浓度（甲醇或甲醇：2-丙醇混合物）和搅拌速度。对于酯化，MI:WCO 比率和酯交换，甲醇:2-丙醇比率也进行了优化。FFA 转化率为 98.27%，生物柴油收率最高为 99.05%，两种碳质载体均表现出与催化剂载体相当的效率。获得的动力学数据符合准一级动力学模型，其中 E _a2.172 kJ/mol和1.219 kJ/mol，酯化和酯交换的A分别为45.61 min ^-1和20.97 min ^-1。由于两种催化剂都显示出良好的可重复使用性，催化剂制备成本仅为 0.047 美元/升酯化油和 0.016 美元/升生物柴油。因此，已建立的具有成本效益的工艺可用于从相容的油混合物中以高产率生产生物柴油，从而减少对专有原料的依赖。