Coking characteristics and deactivation mechanism of the HZSM-5 zeolite employed in the upgrading of biomass-derived vapors

Characterization of deactivated and regenerated zeolite ZSM-5-based catalyst extrudates used in catalytic pyrolysis of biomass

“…This XRD peak may be attributed to the attapulgite phase, suggesting a possible re-dispersion of the attapulgite binder upon reaction. Alternatively the better resolution of the 26.6°XRD peak could be due to the disappearance of the graphite peak of coke, which locates at a very similar position to quartz [36][37][38].…”

“…5 and Figs. S4-S6; bigger (25-50 nm) spherical shapes (2), which might correspond to quartz, a common impurity in attapulgite [45,46]; and amorphous carbonaceous deposits [47][48][49] and graphite flakes (3) [36,37,50]. TEM examination revealed the used samples to be more agglomerated than the fresh, in particular after 40 min reaction (Fig.…”

Bifunctional Mg−Cu‐Loaded β‐Zeolite: High Selectivity for the Conversion of Furfural into Monoaromatic Compounds

“…[3,4] Jae et al [5] investigated the shape selectivity of zeolite on the conversion of glucose into aromatics, and found that glucose-derived vapors can easily diffuse into the pores of ZSM-5 and ZSM-11, resulting in the formation of aromatics with high yield. [8] Therefore, it is necessary to improve the activity, selectivity and stability of zeolite for BTXs production by avoiding PAHs and coke formations. However, even though these zeolites showed good catalytic activity for deoxygenation with high selectivity toward aromatic hydrocarbons, a large amount of undesirable polycyclic aromatic hydrocarbons (PAHs) such as indenes and naphthalenes were also generated in the upgraded bio-oil due to the further aromatization and alkylation of MAHs.…”

Hydrodeoxygenation of raw bio-oil towards platform chemicals over FeMoP/zeolite catalysts

“…This way, the obtained results correspond to both the transitory period of the reaction (TOS = 0-5 h, while progressive catalyst deactivation takes place) as well as to the pseudosteady state (TOS > 5 h), which is more interesting from an industrial perspective.In all cases, the main products at TOS = 1 h are gases and coke. Gases originate from decarbonylation/decarboxylation reactions and coke is formed through repolymerization/condensation reactions of bio-oil oxygenated on the outter Surface of the catalyst particles[35] and also from condesation of aromatic compounds within the micropores of the catalyst[40]. Water is also formed by dehydration of oxygenates at the initial hours of reaction for the supported catalysts and resulted the predominant product fraction for all the catalysts at TOS > 2 h, with yields of 22-62 wt%, followed by carbon products in the case of the zeolite-supported catalysts, and gas+coke products when using the bulk FeMoP phase.…”