In-situ reactive extraction of castor seeds for biodiesel production using the coordinated ultrasound - microwave irradiation: Process optimization and kinetic modeling

Kartikkumar Thakkar; Keyur Shah; Pravin Kodgire; Surendra Singh Kachhwaha

doi:10.1016/j.ultsonch.2018.08.007

In-situ reactive extraction of castor seeds for biodiesel production using the coordinated ultrasound - microwave irradiation: Process optimization and kinetic modeling

Ultrason Sonochem. 2019 Jan:50:6-14. doi: 10.1016/j.ultsonch.2018.08.007. Epub 2018 Aug 13.

Authors

Kartikkumar Thakkar¹, Keyur Shah², Pravin Kodgire³, Surendra Singh Kachhwaha⁴

Affiliations

¹ Mechanical Engineering Department, School of Technology, Pandit Deendayal Petroleum University, Gandhinagar 382007, Gujarat, India; Center for Biofuel & Bioenergy Studies, Pandit Deendayal Petroleum University, Gandhinagar 382007, Gujarat, India. Electronic address: kartik.tphd16@sot.pdpu.ac.in.
² Mechanical Engineering Department, School of Technology, Pandit Deendayal Petroleum University, Gandhinagar 382007, Gujarat, India; Center for Biofuel & Bioenergy Studies, Pandit Deendayal Petroleum University, Gandhinagar 382007, Gujarat, India.
³ Chemical Engineering Department, School of Technology, Pandit Deendayal Petroleum University, Gandhinagar 382007, Gujarat, India; Center for Biofuel & Bioenergy Studies, Pandit Deendayal Petroleum University, Gandhinagar 382007, Gujarat, India. Electronic address: pravin.kodgire@sot.pdpu.ac.in.
⁴ Mechanical Engineering Department, School of Technology, Pandit Deendayal Petroleum University, Gandhinagar 382007, Gujarat, India; Center for Biofuel & Bioenergy Studies, Pandit Deendayal Petroleum University, Gandhinagar 382007, Gujarat, India. Electronic address: surendra.singh@sot.pdpu.ac.in.

PMID: 30122463
DOI: 10.1016/j.ultsonch.2018.08.007

Abstract

The present study demonstrates innovative and industrially viable in-situ biodiesel production process using coordinated ultrasound-microwave reactor. Reactive extraction process has been carried out by mixing grinded castor seeds with methanol in the presence of base catalyst (KOH). Response surface methodology coupled with central composite design has been applied for process optimization to achieve maximum yield. The result shows that maximum biodiesel yield of 93.5 ± 0.76% was obtained under favorable conditions of: molar ratio (350:1), catalyst (w/w) (1.74%), reaction temperature (43 °C) and reaction time (30 min). Regression equation obtained for the model having (R²), and (R²_adj) equal to 0.9737 and 0.9507 respectively shows goodness of fit. First time reaction kinetics as well as oil extraction kinetics studies have been performed on coordinated ultrasound-microwave reactor. Assuming pseudo first order reaction activation energy was found to be 28.27 kJ·mol^-1 and activation energy for oil extraction was observed to be 9.11 kJ mol^-1. Estimated activation energy for the reaction kinetics and extraction kinetics was reduced by 27%, reaction rate constants were eight to ten times higher and diffusion coefficient was found to be two times higher in case of hybrid system as compared to conventional mechanical stirring technique. Estimated thermo-physical properties of biodiesel were found in agreement with ASTM and DIN standards in comparison to gasoline diesel.

Keywords: Castor oil methyl ester; Central composite design; Coordinated microwave-ultrasound; In-situ; Kinetic study.