Oil sludge addition enables prediction of biomass pyrolysis product profiles by synergistic behaviors between biomass components and oil sludge

The complex composition of biomass leads to wide variations of pyrolysis products, which makes the prediction of pyrolysis product profiles greatly difficult. This study firstly found that biomass co-pyrolysis with oil sludge (OS) made product profiles well-predictable. Co-pyrolysis of three biomass components, hemicellulose (Hemi), cellulose (Cel), and lignin (Lig) with OS increased the comprehensive pyrolysis index compared to OS pyrolysis alone. Moreover, co-pyrolysis with OS led to a weaker intensity of gas release (CH4, H2O, CO, and CO2) and lower apparent activation energies than pyrolysis of individual biomass components. OS/Hemi and OS/Cel co-pyrolysis promoted the formation of char and gaseous products as well as the generation of oxygenates in oil products. On the other hand, OS/Lig co-pyrolysis enhanced gas production and contributed to the formation of hydrocarbons like long straight-chain alkanes with less oxygenates formation. Using co-pyrolysis results of OS/Hemi, OS/Cel, and OS/Lig, the product yields and oil compositions of OS/real biomass co-pyrolysis (woody biomass and rice straw) were successfully predicted based on only Hemi/Cel/Lig composition ratios of the biomass. Because direct interactions between OS and biomass components might be prior to pyrolytic interactions among biomass components, it enables the excellent predictability. It also proposes that OS or other appropriate materials might facilitate the industrial applications of miscellaneous biomass pyrolysis owing to reliable predictions of product profiles based on the biomass composition ratios.