Biodiesel was produced from waste coffee grounds (WCGs) using solid catalysts manufactured from waste scallop shells through a one-step direct process (OSDP) comprising lipid extraction and simultaneous transesterification in a reactor. To facilitate the reuse of the solid catalysts, a cartridge containing the solid catalysts was devised, and the optimal conditions of the OSDP with the cartridge were investigated. Agitation speed was a critical factor for the operation of this novel process, and should be at least 200 rpm. The optimal total volume of the mixture consisting of methanol and n-hexane (9 mL/g-WCGs) was determined, along with the volume fraction of methanol (18.0%) and n-hexane (82.0%) using a statistical Mixture-Design technique. The optimum catalyst concentration (5.0 wt%), temperature (50°C), and reaction time (13 h) were determined through a Full Factorial Design, followed by a One-Factor-at-a-Time technique. Under these optimum conditions, 8.7% of biodiesel yield was obtained. The concentration of solid catalysts in the cartridge significantly influenced the reuse number of the cartridge. The cartridge containing 5.0 wt% of solid catalysts was reused only for the 2nd round of operation, while that containing 100 wt% of solid catalysts was successfully reused until the 12th round of operation, without a noticeable decrease in biodiesel yield.

生物柴油是由废咖啡渣（WCG）使用一种由扇贝贝壳制成的固体催化剂通过一步一步直接工艺（OSDP）制成的，该工艺包括脂质提取和在反应器中同时进行酯交换反应。为了促进固体催化剂的再利用，设计了装有固体催化剂的药筒，并研究了具有该药筒的OSDP的最佳条件。搅拌速度是该新方法操作的关键因素，应至少为200 rpm。该混合物的组成和甲醇的最佳总体积Ñ己烷（9毫升/克-WCGs）测定，用甲醇（18.0％）和体积分数沿Ñ使用统计混合物设计技术的正己烷（82.0％）。最佳催化剂浓度（5.0 wt％），温度（50°C）和反应时间（13 h）通过全因子设计确定，然后采用“一次因子”技术确定。在这些最佳条件下，获得了8.7％的生物柴油收率。筒中固体催化剂的浓度显着影响筒的再利用次数。含有5.0 wt％固体催化剂的药筒仅可在第二轮操作中重复使用，而含有100 wt％固体催化剂的药筒可成功地重复使用至第12轮操作，而生物柴油收率却没有明显下降。