In situ catalytic upgrading of pyrolysis vapours from vacuum pyrolysis of rape straw over La/MCM-41

Abstract

By combining the large pore size of MCM-41 and the adjustable acid property of La, La/MCM-41 catalysts with La loading mass fractions of 1%, 5% and 10% were prepared and used in the catalytic upgrading of pyrolysis vapours from vacuum pyrolysis of rape straw to obtain high-value bio-oil. MCM-41 zeolite before and after the La loading was characterized in detail by TEM, Py-IR and TG. The characterization data showed that the amount of Brönsted and Lewis acid sites on the surface of La/MCM-41 increased. The highest hydrocarbon content (35%), and the highest higher heating value (34 MJ kg−1) were obtained at a La loading of 5% (La(5)/MCM-41). This may be closely related to the promotion of the reaction efficiency of the active sites with proper acid concentrations. Simultaneously, the coke content of the catalyst decreased further, and the selectivity for the high-value aromatic hydrocarbons increased. Considering the suitable concentration of La(5)/MCM-41 with strong acidity and stability, it is more appropriate for use in the upgrading of pyrolysis vapour for liquid fuel production.