Biodiesel production from renewable biosources ternary oil blends and its kinetic-thermodynamic parameters using Eyring Polanyi and Gibb's-Duhem equations

Abstract

This work reports the blends of oils from renewable bioresource for biodiesel synthesis via the ethanolysis of a derived base catalyst from calcined shell powder. The derived base catalyst was calcined and characterized using FTIR, SEM, XRF, BET adsorption, and qualitative analysis. Biodiesel production was via transesterification reaction, and the process conversion was optimized through central composite design (CCD) with references to four factors (reaction period, catalyst amount, reaction temperature, and E-OH/OMR) on the response (biodiesel yield). Kinetic and thermodynamic parameters of biodiesel conversion were evaluated, and the strength of catalyst derived was tested via catalyst reusability test.Results showed that a blend ratio of 32:35:33 was enough to produce a low acid value, low viscous and low-density blend oil of the biodiesel produced via transesterification. The process optimization via CCD produced a predicted optimum biodiesel yield of 99.44% (wt. /wt.) at reaction period of 81.91 min, reaction temperature of 67.00 °C, and catalyst amount of 3.28 (% wt.), and E-OH/OMR of 5.56 (vol./vol.). This optimum yield was validated in triplicate; an average optimum yield of 99.44% (wt./wt.) was obtained in 30 experimental runs. The derived catalyst was found to be rich in calcium oxide (CaO) with 97.21% concentration. Kinetic studies revealed the highest reaction rate constant of 10.00 min−1, and activation energy (Ea) of 572.13 J.mol−1. The thermodynamic parameters ΔH*,ΔS*,andΔG* were estimated as 55.71 × 10−3 J.mol−1, -1.08 kJ.mol−1, and 381.24 kJ.mol−1 at temperature of 353 K. The produced biodiesel properties conformed to the recommended standard.