Optimization of the comparative continuous process of ethyl and methyl ester productions using a static mixer reactor: a response surface methodology approach

ABSTRACT

Static mixer was used as the continuous reactor in the biodiesel production. This study reports methyl ester and ethyl ester production from refined palm oil (RPO) using a 10 m long static mixer reactor. Alcohol content (vol.%), KOH (g.L⁻¹), and static mixer length (m) were optimized to determine the ester purities with response surface methodology. As a result, 96.5 wt.% ester purity was substituted into the predicted models of FAME and FAEE. The appropriate conditions for methanolysis of 44.7 vol.% of methanol, 11.2 g.L⁻¹ of KOH, and 4.8 m of static mixer length was obtained. The appropriate condition for ethanolysis were 45.3 vol.% of ethanol, 12.5 g.L⁻¹ of KOH, and 5.1 m of static mixer length. From all statistical analysis data, KOH has a less significant effect when compared with other parameters, whereas alcohol content and static mixer length are first- and second-key, respectively. Alcohol consumption and reaction time for ethanolysis are more than for methanolysis. Regarding glycerol–ethyl ester separation, the glycerol phase of ethyl ester is more difficult than methyl ester.

KEYWORDS:

• Methyl ester
• ethyl ester
• static mixer
• continuous
• biodiesel

Acknowledgments

This work was supported by the Higher Education Research Promotion and National Research University Project of Thailand, Office of the Higher Education Commission, and the Faculty of Engineering, Prince of Songkla University by providing research funds.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Higher Education Research Promotion and National Research University Project of Thailand [grant number ENG570596S], Office of the Higher Education Commission; Prince of Songkla University [grant number ENG570123c].