Azolla pinnata methyl ester production and process optimization using a novel heterogeneous catalyst

This study concentrated on utilizing a novel heterogeneous dolomite catalyst in transesterification of Azolla pinnata algae oil with methanol to convert Azolla pinnata methyl ester (AME). The thermophysical properties of the catalyst were characterized by XRF, XRD, FTIR, and BET analysis. The optimized AME yield of 88.7% was obtained for the methanol to oil molar ratio (30:1), catalyst weight% (4 wt%), and operating temperature of (70 degrees C) through central composite design (CCD) in response surface methodology (RSM) technique. Five different proportions of Azolla pinnata methyl ester (AME) viz., 10%, 20%, 30%, 40% and 100% by volume were blended with 90%, 80%, 70%, 60% and 0% by volume of diesel. These AME test fuel blends were named AME10, AME20, AME30, AME40, and AME100. American Society for Testing and Materials (ASTM D6751) standards followed to testing the thermophysical properties of prepared biodiesel. AME fuel blends were tested in the single-cylinder variable compression ratio (VCR) engine with varied compression ratios (CR) of 16:1, 17:1, and 18:1 for different loadings at a constant speed of 1500 rpm. The performance, in-cylinder combustion, and exhaust emission results were concluded among five different diesel-AME blends at varied compression ratios. The obtained results for AME blends were compared with the diesel fuel under the same working conditions. At peak load condition, AME30 test fuel with CR18:1 gives a reduction of CO (14.0%), HC (12.06%) and smoke opacity (5.88%) and slight increment in NOx (2.46%) emissions as well as reduced BTE (10.20%) and increased BSEC (17.33%) were obtained related to diesel fuel. Better diffusion phase combustion was recorded for AME blends due to their higher cetane value than neat diesel. (C) 2021 Elsevier Ltd. All rights reserved.