Co-pyrolysis of a coal/biomass blend into biofuel: optimization of operational parameters using central composite design

Abstract

Researchers are attempting to replace fossil and petro-based fuels with renewable and green fuels. Knowing the optimum values of pyrolysis parameters during the production of biofuel from biomass/coal blends is important to obtain biofuel in the desired yield and quality. In this study, a central composite design was used in order to optimize pyrolysis parameters to obtain biofuel from the co-pyrolysis of a coal (lignite)/biomass (pistachio seeds) mixture in a well-swept resistance fixed bed reactor. Knowing the optimum values of different parameters affecting the biofuel yield and quality is very important in terms of the most efficient conditions and the economical production of energy. The effects of some operational parameters, like final temperature (factor A), heating rate (factor B) and percentage of lignite (factor C), were optimized through the central composite design method, and their behaviors were analyzed using analysis of variance. While the linear and quadratic effects of the final temperature and heating rate on the biofuel yield were significant, only the linear effect of the percentage of lignite was found to be important; on the other hand, the effects of the binary interaction between the factors were found to be insignificant. A quadratic equation was proposed to predict the behavior of the process under various conditions with an R-2 of 98.19. The best condition was predicted at a final temperature of 595 degrees C, a heating rate of 458 degrees C/min and a percentage lignite of 16.7% with maximum biofuel yield of 61.23%. (c) 2022 Society of Chemical Industry and John Wiley & Sons, Ltd