Low-Cost Feedstock Conversion to Biodiesel via Ultrasound Technology

Abstract

Biodiesel has attracted increasing interest and has proved to be a good substitute for fossil-based fuels due to its environmental advantages and availability from renewable resources such as refined and waste vegetable oils. Several studies have shown that biodiesel is a better fuel than the fossil-derived diesel in terms of engine performance, emissions reduction, lubricity and environmental benefits. The increasing popularity of biodiesel has generated great demand for its commercial production methods, which in turn calls for the development of technically and economically sound process technologies. This paper explores the applicability of ultrasound in the optimization of low-cost feedstock -in this case waste cooking oil -in the transesterification conversion to biodiesel. It was found that the conversion efficiency of the waste oil using ultrasound was higher than with the mechanical stirring method. The optimized variables of 6:1 methanol/oil ratio at a reaction temperature of 30 °C and a reaction time of 30 min and 0.75% KOH (wt/wt) catalyst concentration was obtained for the transesterification of the waste oil via the use of ultrasound.

Novel zeolite Na-X synthesized from fly ash as a heterogeneous catalyst in biodiesel production

“…Characterization of fly ash applied has been presented elsewhere [19]. The synthesized fly ash based zeolite Na-X catalysts (FA/Na-X) and the ion exchanged fly ash based zeolite X (FA/K-X) were characterized using the techniques described below.…”

“…The chemical composition, pore size distribution and ion exchange properties of zeolite are responsible for their versa-tile catalytic behaviour [10,11]. In a previous study by the authors, South African Class F fly ash loaded with potassium was used as a solid-base catalyst in the transesterification of sunflower oil to methyl esters to make a meaningful utilization of waste coal fly ash in biodiesel catalysis [19]. With the cost of synthesizing zeolite X from coal fly ash estimated to be almost one-fifth of that of producing commercial zeolites [7], the applications of the fly ash based hierarchical zeolites in biodiesel production is expected to be a low cost substitute for the commercially available zeolite X synthesized using conventional feedstocks.…”

Utilization of Agroindustry Wastewater as Growth Medium for Microalgae based Bioenergy Feedstock in Indonesia (an Overview)

“…However, in the international market, the most technically feasible and commercialized alternative renewable fuel sources are biodiesel and bioethanol [7]. Several researchers found that oil from microalgae could be converted to biodiesel, by using supercritical and microwave methods [8], ultrasound methods [9,10], and direct transesterification (in situ) [11].The last method is one of the most promising technologies due to the simple process and lower energy consumption to produce biodiesel from microalgae [8,12,13]. By using In situ transesterification, energy consumption could be lowered due to bypassing lipid extraction.…”

Preliminary Testing of Hybrid Catalytic-Plasma Reactor for Biodiesel Production Using Modified-Carbon Catalyst

“…The maximum yield of biodiesel that can be achieved was 90% at a temperature of 40 o C and at atmospheric pressure. Meanwhile, the use of ultrasound in the transesterification of waste cooking oil by Babajide et al [20] obtain a conversion of >90% at temperature of 30 o C and a pressure of 1 atm. However, weakness of ultrasound technology on the performance of this reactor are requiring quite long reaction time of about 30 minutes, the formation of glycerol as a byproduct and requiring a homogeneous alkaline catalyst.…”

“…Advanced methods developed in the production of biodiesel were supercritical [16,17], microwave [18,19], ultrasonic [20,21], and plasma technology [22,23] methods. Some researchers studied the effect of the use of the reactor type to biodiesel yield as well as the process efficiency in biodiesel production [21,[24][25][26].…”