Vol. 52 No. 6 2019 545 Copyright © 2019 The Society of Chemical Engineers, Japan Journal of Chemical Engineering of Japan, Vol. 52, No. 6, pp. 545–553, 2019 Intensification of Continuous Biodiesel Production Using a Spinning Disc Reactor Weerinda App amana 1 , Patcharaporn Sukj arern 1,3 , Kanokwan Ngaosuwan 2 and Suttichai Assabumrungrat 3 1 Department of Chemical and Materials Engineering, Faculty of Engineering, Rajamangala University of Technology anyaburi, Pathumtani, ailand 2 Chemical Engineering Division, Engineering Faculty, Rajamangala University of Technology Krungthep, Bangkok, ailand 3 Center of Excellence in Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, ailand Keywords: Spinning Disc Reactor (SDR), Biodiesel, Waste Cooking Oil, Grooved Disc, Kinetics The present study investigates a spinning disc reactor (SDR) as a process intensification technology for continuous biodiesel production. Refined palm oil (RPO) and waste cooking oil (WCO) were transesterified with methanol in the presence of NaOH as a homogeneous catalyst. The effects of operating temperature, methanol to oil molar ratio, catalyst loading, and rotational speed were investigated. The highest fatty acid methyl ester (FAME) yields as high as 97.0% and 90.9% could be achieved at a very short residence time of 2–3 s when using RPO and WCO, respectively, as feedstocks. It was found that the grooved disc surface plays an important role in increasing FAME yield obtained from WCO to 97.7% compared to the conventional mechanical stirring. This FAME yield also conforms to the EN 14103 standard. Moreover, the calculated values of activation energy based on the first order reaction kinetics were 57.5 and 43.4 kJ mol −1 for RPO and WCO, respectively. The performance of SDR in terms of yield efficiency was also compared with other reactors. The use of SDR offers a significant reduction in the reaction time for the transesterification, especially when compared with the reaction time of 90 min required for the conventional mechanical stirred reactor. It was demonstrated that the SDR is the most promising intensification reactor for continuous biodiesel production from waste cooking oil. Introduction Limited fossil resources and environmental problems caused by combustion of fossil fuels have generated a de- mand to fnd an alternative energy source to meet the increasing world energy needs (Avhad and Marchetti, 2015). Biodiesel has become of interest due to its envi- ronmental-friendliness, non-toxicity, sustainability and high heating values comparable to diesel fuel (Choedkiatsakul et al., 2015). It can be produced from edible or non-edible oil sources, but high feedstock costs are the major obstacle to the commercialization of biodiesel production from ed- ible oils. For this reason, waste cooking oil has become a more attractive feedstock. Waste cooking oil costs, on av- erage, only 20% of the cost of refned cooking oil (Chuah et al., 2015). Furthermore, the utilization of waste cooking oil as a feedstock of biodiesel provides a more sustainable and environmental-friendly route for disposal (Chen et al., 2009; Tan et al., 2011). Te conventional technique for biodiesel production is to activate the basic catalyst with methanol, and then in- timately mix this with the triglyceride (TG) to form bio- diesel (Fatty Acid Methyl Ester, FAME) and glycerol (GL), typically in a stirred tank batch reactor. However, trans- esterifcation of TGs involves three factors which limit bio- diesel yield; mass transfer between oil and methanol phase, reaction kinetic regime and ester formation controlled by equilibrium (Bargole et al., 2017). Te major limiting step is the mass transfer due to immiscibility of oil and alco- hol (Likozar et al., 2016). A large number of researchers have proposed various efficient intensifcation reactors to diminish the mass transfer resistance and to enhance the reaction rates as well as biodiesel yield. Tese include the microchannel reactor (Rahimi et al., 2016), static mixer re- actor (Sungwornpatansakul et al., 2013), reactive distillation (Petchsoongsakul et al., 2017), high pressure homogenizers (Laosuttiwong et al., 2018), ultrasonic (Poosumas et al., 2016) and microwave assisted reactor (Hong et al., 2016). Gupta et al. (2015) studied the synthesis of biodiesel from used frying oil in an ultrasonic assisted reactor. Te results showed that the role of an ultrasonic feld to induce an ef- fective emulsifcation and mass transfer was important and the rate of ester formation was signifcantly enhanced. Te microwave reactor was used for transesterifcation of refned palm oil in the presence of methanol and sodium hydroxide (NaOH), and found that high biodiesel yield of 99.4% was obtained in a short residence time of 1.75 min with half the energy consumption compared to the conventional process. However, scaling up the process is a major hurdle for ultra- Received on November 15, 2018; accepted on February 14, 2019 DOI: 10.1252/jcej.18we322 Correspondence concerning this article should be addressed to W. Appamana (E-mail address: Weerinda.a@en.rmutt.ac.th). Research Paper