Preparation of Aromatic Hydrocarbons from Catalytic Pyrolysis of Digestate

Catalytic pyrolysis of digestate to produce aromatic hydrocarbons can be combined with anaerobic fermentation to effectively transform and utilize all biomass components. The study on the feasibility of preparing aromatic hydrocarbons by catalytic pyrolysis of digestate can provide guidance for the treatment and high-value utilization of digestate, and achieve the purpose of changing waste into high-value products, which is of great significance. This study explored whether catalytic pyrolysis of digestate is feasible to prepare aromatic hydrocarbons by analyzing the thermogravimetric characteristics, pyrolysis characteristics, and catalytic pyrolysis characteristics of digestate. For digestate pyrolysis, an increase in temperature was found to elevate the CO, CH4, and monocyclic aromatic hydrocarbon (benzene, toluene, and xylene; BTX) content, whereas it decreased the contents of phenols, acids, aldehydes, and other oxygenates. Furthermore, the catalytic pyrolysis process effectively inhibited the acids, phenols, and furans in the liquid, whereas the yield of BTX and the selectivity of X was increased significantly after adding ZSM-5. ZSM-5 also inhibited the production of nitrogenous compounds.