Optimizing biodiesel production from Madhuca Longifolia oil: Catalyst comparison and process parameters optimization

Abstract

The current research delves into the transesterification of Madhuca Longifolia seed oil into biodiesel, employing both homogeneous catalysts (KOH and NaOH) and a heterogeneous catalyst derived from waste eggshell. For the homogeneous system, various process variables such as reaction temperature, catalyst quantity, and oil to molar ratio were meticulously optimized to assess their impact on biodiesel yield. The optimal conditions for the NaOH-catalyzed transesterification reaction were determined as follows: 0.4 gm NaOH, 1:6 oil to methanol molar ratio, 60°C reaction temperature, and a reaction time of 60 minutes. Results indicated that NaOH outperformed KOH, yielding a remarkable 96% conversion. In the case of the heterogeneous catalyst derived from waste eggshell, a batch reactor was employed. Here, 100 ml of Madhuca Longifolia oil was mixed with 26.67 gm of methanol, maintaining a methanol to Madhuca Longifolia oil molar ratio of 9:1. The eggshell-based catalyst was utilized at a proportion of 3 wt% relative to the oil weight, with a reaction temperature of 60°C and a reaction time of 2 hours. This process yielded a biodiesel with an 87% conversion. The produced biodiesel was evaluated in accordance with the ASTM D6751 standard and was found to meet the acceptable quality limits. In summary, this study underscores NaOH as a superior catalyst for generating biodiesel with desirable properties from non-edible Madhuca Longifolia seed oil. Additionally, waste eggshell emerges as a viable option for producing biodiesel as a heterogeneous catalyst.