Biodiesel Production Potential from Littered Edible Oil Fraction Using Directly Synthesized S-TiO2/MCM-41 Catalyst in Esterification Process via Non-Catalytic Subcritical Hydrolysis

Md Sufi Ullah Siddik Bhuyan,Yong Chan Seo,Younghwan Chu,Abul Hasnat Md Ashraful Alam

doi:10.3390/en10091290

Abstract

Due to uncontrolled consumption of fossil fuel it is necessary to use alternative resources as renewable energy. Among all the available liquid fuels biodiesel has drawn attention for producing less emissions and having less aromatic contents than diesel and because it can also be obtained from inferior grade feedstocks. Since the various uses of fats and oils have increased, a significant amount of waste animal fat and used edible oil is generated every year. In this work, we produced biodiesel from littered edible oil fraction (LEOF) via hydrolysis followed by catalytic esterification. Nearly 90% free fatty acids (FFA) content was achieved at 275 °C, after 45 min during hydrolysis and linoleic acid (C18:2) was observed to be the highest component. Compared to refined soybean oil (SBO) the reaction rate was accelerated by the auto-catalytic behavior of free fatty acids (FFA) in littered edible oil fraction (LEOF). For catalytic esterification, S-TiO2/MCM-41 catalyst was directly synthesized and characterized by using XRD, SEM, NH3-TPD and Brunauer Emmett Teller (B.E.T). The parameters such as; SO4−2 content, TiO2 loading and calcination temperature were varied to get optimum free fatty acids (FFA) conversion. Fatty acid methyl ester (FAME) conversion was 99.29% using 1% S-TiO2/MCM-41 catalyst at 240 °C whereas 86.18% was observed with 3.5% catalyst at 180 °C with 20 min. Thus, using S-TiO2/MCM-41 catalyst in esterification via hydrolysis would be a better option for treating low quality feedstocks.

Highlights

With the increasing global trend in natural resources consumption, the supply of fossil fuels is going to start to diminish
Two independent samples of raw littered edible oil fraction (LEOF) and refined soybean oil (SBO) were collected from a restaurant and a grocery shop located in Sangji University, Wonju-si, and Gangwon-do, South Korea on different days and stored under ambient conditions until the pretreated samples were used for fatty acid production
We examined the comparative performance of the catalytic activities of synthesized S-TiO2/MCM-41 with conventional liquid H2SO4, Ti(SO4)2 and TiO2 under sub- and supercritical methanol free fatty acids (FFA) treatment

Summary

Introduction

With the increasing global trend in natural resources consumption, the supply of fossil fuels is going to start to diminish. First generation biodiesel, produced from edible oil feedstocks, represents a more sustainable source of renewable energy, but in the long run it will not be socially and economically viable as it requires a significant share of the available edible oil crops for fuel production. To overcome these challenges, there is a growing demand for non-edible/unproductive sources of feedstocks, called 2nd generation biodiesel, to produce renewable fuel all over the world [2].

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Results

Conclusion