Catalytic Upgrading of Fast Pyrolysis Products with Fe-, Zr-, and Co-Modified Zeolites Based on Pyrolyzer–GC/MS Analysis

To explore the influence of Fe-, Zr-, and Co-modified zeolites on bio-oil characteristics, the catalytic fast pyrolysis of cellulose combined with sawdust and cotton stalk was investigated using a pyrolyzer reactor. The results indicate that Fe-loaded zeolite favors naphthalene and 1-methylnaphthalene formation through catalytic deoxygenation and hydrocarbon formation. Zr-modified zeolite enhances the contents of ketones and aromatics with higher benzene and p -xylene selectivity. Co leads to higher production of anhydrous sugars but suppresses the progress of aromatics evolution, whereas the selectivity of Co for toluene and p -xylene is the highest. A comprehensive reaction network is also proposed to describe the cellulose catalytic pyrolysis process. Considering the catalytic adaptability, catalytic pyrolysis of typical biomass samples with Fe/HZSM-5 was investigated. The total contents of aromatic hydrocarbons are in the following order: sawdust > cellulose > cotton stalk. The selectivities of naphthalene and 2-methylnaphthalene in cellulose are the highest, while the selectivities of benzene and its derivatives in sawdust and cotton stalk are higher.