Scaling-up heterotrophic cultures of C. Pyrenoidosa microalgae for sustainable synthesis of low-density biodiesel mixtures and predict CI engine behavior at optimal proportions

摘要

Abstract Sustainable fuel production techniques and feedstocks are essential to meet the future energy demand. In this context, the present study is aimed at sustainably producing low-density biodiesel from Chlorella pyrenoidosa microalgae by heterotrophic means and processed using enzymatic transesterification. To assess the potential of the low-density biodiesel, the fatty acid methyl profile is analyzed and homogenized with diesel fuel at 10, 20, 30, and 40 (v/v/) and tested in a light commercial compression ignition engine at maximum throttle pedal position condition. Furthermore, to identify the optimal mixture proportion and predict the engine outputs, statistical tools like multivariate principal component analysis–desirability approach are employed. From the study, it was inferred that the biomass concentrations of the cultures from 100, 200, and 300L stir tank bioreactor reached up to 5.15, 4.24, and 4.36?g/L on scaling-up. The maximum biodiesel conversion rate of 98 was achieved at an optimal reaction time of 12?h and temperature of 37?°C during enzymatic transesterification. During engine testing, the lowest fuel consumption of 0.41?kg/kWh was attained at full load condition while operating on 40 biodiesel composition. At 20 biodiesel composition, hydrocarbon, nitrogen oxides, and smoke emissions reduce by 44.26, 23.55, and 11.69 as compared to diesel fuel at full load condition. Maximum in-cylinder pressure and heat release rate were achieved by CP30D70 at full load condition as compared to diesel fuel. The optimal biodiesel proportion was identified as 20 and 30 based on the cluster similarly index of 89.67 and desirability value.