Performance and evaluation of calcined limestone as catalyst in biodiesel production from high viscous nonedible oil

Abstract

Biodiesel production by transesterification of rubber seed oil (RSO) using calcium oxide (CaO) derived from calcined limestone as a heterogeneous catalyst is presented in this study. Optimization of process parameters affecting the conversion of RSO to biodiesel is done by design of experiments (DOE) and an effective comparison of two different optimization methods, namely, response surface methodology (RSM) and artificial neural networks (ANN) is presented. A high conversion of 95.2% was obtained at 12:1 methanol: Oil molar ratio, 4 (wt%) catalyst and 5 hr of reaction time. The proposed design model of RSM is found to fit well with the predicted conversion and with molar ratio and reaction time as the significant process parameters affecting the conversion. Best validation performance of 8.8991 occurred at epoch 4 with a mean square error (MSE) of 1.55 in ANN model trained with Levenberg-Marquardt algorithm. By comparing the predicted coefficient of determination, R 2 , values of 0.8452 obtained by using RSM, and 0.9939 obtained by using ANN for biodiesel conversion, it is concluded that ANN model is the best model for predicting the percentage conversion of RSO to biodiesel with minimum error between experimental and predicted values. K E Y W O R D S artificial neural networks, biodiesel, limestone, optimization, response surface methodology, transesterification

Identification of sensitive process parameter of rubber seed oil conversion to biodiesel using fluorite and calcined limestone as catalysts—Uncertainty error analysis

“…Biodiesel from RSO using synthesized catalysts is prepared as per the procedure mentioned in our previous reported works 18,19 . From these studies it was concluded that RSO conversion of 95.95% (using fluorite) and 95.2% (using calcined limestone) to biodiesel was observed at optimum process conditions of 12:1 methanol: oil molar ratio (mol/mol), 4 (wt %) of catalyst concentration, and 5 (h) of reaction time.…”

Statistical analysis of experimental factor optimization in acid esterification of rubber seed oil

“…A reasonable acid value within the limits of ASTM standard was also observed for the synthesized biodiesel of all the four catalysts used. All the above results including the physico‐chemical properties of raw RSO and synthesized biodiesel were explained in detail as reported in our previous studies (Bharadwaj et al., 2019a, 2019b, 2019c; Sai Bharadwaj et al., 2020).…”

“…including the physico-chemical properties of raw RSO and synthesized biodiesel were explained in detail as reported in our previous studies (Bharadwaj et al, 2019a(Bharadwaj et al, , 2019b(Bharadwaj et al, , 2019cSai Bharadwaj et al, 2020).…”

“…The esterified RSO prepared as per the conditions presented in this study was used in biodiesel production (as reported in our earlier studies) using different heterogeneous catalysts. A high conversion of 99.7%, 95.95%, 95.20%, and 98.9% was observed while working with calcined eggshells (Bharadwaj et al., 2019a), fluorite (Bharadwaj et al., 2019b), calcined limestone (Bharadwaj et al., 2019c), and impregnated catalyst (Al 2 O 3 /calcined eggshells) (Sai Bharadwaj et al., 2020), respectively, as catalysts. The conversion percentage of esterified RSO to biodiesel was determined using 1 H nuclear magnetic resonance analysis.…”

Synthesis of sodium titanate catalysts using a factorial design for biodiesel production

“…Transesterification reaction was carried out according to the following conditions: a methanol:oil molar ratio of 6:1 at 55°C for 5 hr at 300 rpm. Of note, 3.4% of catalyst was used in all of the tests to compare the activity of CaO catalyst reported in the work of Camacho an collaborators 25 and Sai Bharadwai and collaborators 26 . The reaction was carried out in a 100 mL beaker, which was placed in a reflux system to prevent methanol evaporation.…”