Enhancement of Biodiesel Production from High-Acid-Value Waste Cooking Oil via a Microwave Reactor Using a Homogeneous Alkaline Catalyst

Abstract

In this study, low quality oils (waste cooking oils) with high acid value (4.81 mg KOH/g) were utilized as the feedstocks for a transesterification reaction enhanced by additional microwave power and the use of an NaOH catalyst. The kinetics of the transesterification reaction under different reaction times and temperatures was studied. It was found that in the microwave-assisted transesterification reaction, the optimum conditions under a microwave power of 600 W were as follows: an NaOH catalyst of 0.8 wt %, a 12:1 molar ratio of methanol to oil, a reaction time of 2 min, and a reaction temperature of 65 °C. The conversion of waste cooking oil into biodiesel reached 98.2% after this short reaction time. This result conformed to 96.5% of the standard value of Taiwan CNS 15072. In addition, with increases in the reaction temperature from 55 to 65 °C, the reaction rate constant increased from 0.635 to 2.396 min−1, and the activation energy required for the transesterification reaction was 123.14 kJ/mole.

New Catalysts for Biodiesel Production under Supercritical Conditions of Alcohols: A Comprehensive Review

“…Moreover, very low catalyst concentrations may not accelerate the reaction towards the products to completion due to emulsification, which negatively affects the phase separation. To confirm this point, Hsiao et al [11] . revealed that when 0.4 wt % was applied instead of 0.2 wt % NaOH as a homogeneous catalyst, the biodiesel conversion rate jumped significantly from 16.3 % to reached 91.4 %.…”

An experimental study on synthesis of ternary biodiesel through potassium hydroxide catalyst transesterification

“…with those of other researchers. 46,59 Biodiesel contains more oxygen, which improves oxidation reactions and reduces CO while raising CO 2 emissions. The production of CO 2 is increased by increasing the applied load in the SCDE, which causes chemical reactions inside the combustion chamber due to higher fuel accumulation at maximum load.…”

“…The saponification value (SV) and acid value (AV) were found out by below equations 45,46 where, V b is the volume of blank titration (ml), V s is the volume of the oil titration (ml) and m is the mass of the oil (g).…”

Effect of Different Parameters on Catalytic Production of Biodiesel from Different Oils

“…As these catalysts are dissolved in alcohol and glycerol, so they cannot be recycled again. In addition, the removal of these catalysts is very difficult which increases the cost of biodiesel 98.…”