Optimizing the catalytic performance of Ni-Ce/HZSM-5 catalyst for enriched C6–C8 hydrocarbons in pyrolysis oil via response surface methodology

Abstract

A response surface methodology (RSM) was used to optimize the C6–C8 hydrocarbons in pyrolysis oil from catalytic upgrading of biomass-derived oxygenated pyrolysis vapour over the Ni-Ce/HZSM-5 catalyst via Box-Behnken design. The effect of operating factors such as pyrolysis reaction temperature, catalyst to biomass mass ratio, and nickel to cerium mass ratio on HZSM-5 was employed via in situ fixed bed reactor. The ANOVA results showed that the operating factors significantly affect the total contents of C6–C8 hydrocarbons in pyrolysis oil. The optimal conditions of factors within this study for the maximum contents of C6–C8 hydrocarbons in pyrolysis oil is attainable at a pyrolysis reaction temperature of 505 °C, catalyst to biomass mass ratio of 1.1:1.0, and nickel to cerium mass ratio of 3.14:2.86. The confirmation runs gave 8.83% and 8.86% of C6–C8 hydrocarbon contents (%) in pyrolysis oil compared with 8.90% of predicted value. The developed quadratic mathematical model is significant due to the P value < 0.05. In addition, all three factors individually influence the upgrading of oxygenated compounds into C6–C8 hydrocarbons due to P value < 0.05. The pyrolysis reaction temperature had the strongest effect on the content of C6–C8 hydrocarbons in pyrolysis oil due to higher F value than other factors.