Free fatty acid optimization and modeling of biodiesel production from high viscous rubber seed oil– A comparative study of RSM and ANN

ABSTRACT

Free fatty acid (FFA) optimization consequent to transesterification of high viscous rubber seed oil by solid base catalyst studied is presented in this work. Presence of more FFA in the feedstock leads to soap formation in the case of base catalysis and hence, pre-treatment is required to reduce the high acid value of raw rubber seed oil. FFA of raw rubber seed oil is reduced to 1.64% by acid catalyzed esterification and the FFA of esterified oil is minimized to 0.115% after biodiesel formation using fluorite (CaF₂) derived from the calcination of fluorspar. Response surface methodology (RSM) equipped with central composite design (CCD) is used for FFA optimization. From the RSM analysis, the FFA of synthesized biodiesel is expressed as a quadratic model having a coefficient of determination, R²of value 0.8179. From the 3D-surface plots and 2D contour plots obtained from RSM analysis, it is observed that reaction time is the most significant process parameter that influences FFA optimization. Artificial Neural Network (ANN) modeling with the Levenberg-Marquardt algorithm is used for model network training in rubber seed oil FFA optimization. Mean square error (MSE) of 7.04 × 10⁻⁴ and coefficient of determination R² value of 0.993 was observed at the best validation performance of 0.0019395 at epoch 5. On comparing the coefficient of determination of R² values observed for both RSM and ANN, it is observed that the value obtained from ANN model fits the data well with minimum error.

KEYWORDS:

• Response surface methodology
• Artificial neural network
• Free fatty acids
• Transesterification
• Biodiesel
• Mean square error

Conflicts of Interest

There are no potential conflicts of interest between authors.

Additional information

Notes on contributors

A.V.S.L. Sai Bharadwaj

A.V.S.L. Sai Bharadwaj (also called as Bharadwaj A.V.S.L.SAI) obtained his B.Tech (2012) from MVGR COE, Vizianagaram and M.tech (Research) (2015) in Chemical Engineering from National Institute of Technology, Rourkela. Currently, he is PhD Research Scholar of Chemical Engineering Department, National Institute of Technology, Tiruchirappalli. His research interests include Heterogeneous catalysis, Alternative Fuels, Process Optimization.

Niju S

Niju S is Assistant Professor (Senior Grade) of Biotechnology at PSG College of Technology, Coimbatore, India. He has obtained hisPh.D in Chemical Engineering from National Institute of Technology, Tiruchirappalli, India in 2015. He received Early Career Research (ECR) Award from Science and Engineering Research Board (SERB), Govt. of India in 2016. His research interests mainly focused on alternate fuels, green catalyst development and biomass energy.

K. M.Meera S Begum

K. M.Meera S Begum graduated from Anna university, Chennai. Doctoral research work was under taken at “Chennai Petroleum Corporation Ltd” (Formerly Madras Refineries Ltd) at R&D division as “MRL Research Fellow” from 1991-95. She is a faculty at the Department of Chemical Engineering, NIT, Tiruchirappalli since 1997. Co-authored three Chemical Engineering books, published by PHI, India. Contributed sponsored and consultancy research projects towards Functional materials for Sustainable environment, and energy funded by MHRD, DST and CSIR. Involvement in professional related activities and administrative responsibilities to serve the community.

Anantharaman N

Anantharaman N (also called as N Anantharaman) (Corresponding Author) obtained his B.Tech (1977) and Ph.D (1985) in Chemical Engineering from Regional Engineering College, Tiruchirappalli, Madras University and M.E (1979) in Chemical Engineering from Indian Institute of Science Bangalore. Currently, he is Professor (HAG) of chemical Engineering and Head of Department of Energy and Environment, National Institute of Technology, Tiruchirappalli. His research interests include Mass transfer, Fluidization, Treatment of Industrial effluents using advanced separation techniques, Alternative fuels and energy conservation.