Biodiesel production from oleic acid and palm fatty acid distillate/ oleic acid using sulfonated carbon

Abstract

Biodiesel has been globally accepted as a substitute to diesel fuel, and is an ongoing subject for research. It is a fuel obtained from renewable sources such as vegetable oils, animal fat, and algal oil. Biodiesel is non- toxic, biodegradable, inflammable, and has a good combustion emission profile. Recently, the application of edible sources in the production of biodiesel has caused a lot of debate due the insecurity on food. Hence, the use of inedible and industrial waste sources such as palm fatty acid distillate (PFAD) and oleic acid (OA). Although, they could be the answer to a more economic biodiesel production due to their availability and low cost, their high free fatty acid (FFA) content causes biodiesel production to be expensive when homogeneous catalysts are used. Hence, the need for a heterogeneous acid catalyst, which is the most economically viable catalyst in the production of biodiesel from low cost feedstocks. In this work, the production of biodiesel (FAME) from oleic acid and PFAD/oleic acid mixed feed using a sulfonated carbon catalyst derived from glycerol was investigated. The synthesized catalyst was characterized using FTIR, BET, FESEM, XRD and TPDNH3 to determine its catalytic activity. Simultaneous esterification/ transesterification of oleic acid, and PFAD/oleic acid mixed feed were carried out using the synthesized catalyst. In addition, Response Surface Methodology (RSM) using Box-Behnken Design was used in optimization of the process variables to study the influence of molar ratio of methanol to oleic acid, and PFAD/Oleic acid mixed feed, catalyst loading and reaction time on the conversion and yield of FAME. For oleic acid conversion and yield, 99% and 97% were obtained respectively. While 98%, 94% and 96% were obtained as PFAD/oleic acid conversion, methyl oleate yield and methyl palmitate respectively.