Parametric study on the catalytic pyrolysis of cellulose using formulated red mud catalyst

Abstract

Abstract A parametric study using a response surface methodology was conducted to investigate bamboo effect of feed rate, gas flow rate, and reaction temperature on the pyrolysis product distribution as well as the levoglucosan (LGA) yield during the formulated red mud (FRM) catalyzed pyrolysis of cellulose (CE). Box–Behnken design with three factors at three different levels was used. The factors used were the reaction temperature (350 °C, 400 °C, and 450 °C), the feed rate (50 g/h, 100 g/h, and 150 g/h), and the gas flow rate (5.6 L/min, 6.7 L/min, and 7.8 L/min). The significance of each factor was determined using the analysis of variance (ANOVA). The total liquid yield was significantly affected by the feed rate and the gas flow rate and it ranged from 30.0 wt% to 60.3 wt% but the temperature effect was less significant. The char/coke residue yield was significantly affected by the reaction temperature and it ranged from 2.7 wt% to 15.4 wt%. The water yield ranged from 8.2 wt% to 18.3 wt% and was significantly affected by the feed rate and the gas flow rate, but not significantly affected by the reaction temperature. The LGA yield reached a maximum of 31.9 wt% and was significantly influenced by the feed rate and the gas flow rate; however, the reaction temperature was statistically insignificant. The regression models developed for the char/coke yield, total liquid yield, water yield, and LGA yield accounted for more than 99.8%, 97.9%, 98.9%, and 96.0%, respectively, of the variability in those yields. The novelty of this work is the development of statistically validated response-surface models for LGA yield and product distribution under scale-relevant, continuous fluidized-bed conditions (continuous feeding, realistic vapor residence time, catalyst–biomass mixing, and downstream quench/condensation constraints), rather than pyroprobe or batch microreactor conditions.