Optimizing the process parameters to maximize palm stearin wax biodiesel yield using response surface methodology

Abstract

ABSTRACT Transformation of vegetable waste into a value added biodiesel is the need of the hour with minimal utilization of available resources. The present work focused on understanding the simulation and optimization capabilities of response surface methodology in the transesterification process during the production of biodiesel from palm stearin wax, a waste by-product during palm oil refining process. Single stage transesterification process was used on the pretreated palm stearin wax with main considerations on the process parameters like reaction duration, methanol to oil molar ratio and catalyst concentration to convert the mono-alkyl triglycerides into fatty acid methyl esters. Response surface methodology predicted the yield of biodiesel using the central composite rotatable design involving the process parameters. The prediction process illustrated the optimum biodiesel yield as 97% at methanol to oil molar ratio of 0.28 v/v, catalyst concentration of 1.9201 g/g and reaction duration of 68.18 minutes and it was found to be comparable with the experimental biodiesel yield. The response surface methodology maximized the yield, and significantly reduced the time duration and energy consumption during the assessment of optimal biodiesel yield. The physiochemical properties of the palm stearin biodiesel were tested as per American Society of Testing and Materials standards and it was found to be within limits. Further, the energy assessment and economic viability for the production of palm stearin biodiesel was also carried out. The optimized process parameters could be implemented for bulk industrial batch production to maximize biodiesel yield from palm stearin wax, a waste by-product thereby maximizing the gain from palm oil.