HZSM5 and HUSY deactivation during the catalytic pyrolysis of polyethylene

In situ fast pyrolysis of biomass with zeolite catalysts for bioaromatics/gasoline production: A review

“…These products diffused into the zeolite pores and underwent a series of reactions including hydrocracking, dehydrogenation, polymerization and oligomerization and during which they consequently blocked the catalyst's pores. Consistent with earlier studies involving hydrocarbons [78,79], the reduction in the amount of acids sites in the H-USY catalyst decreased the yield of the desired reaction products (i.e., aromatics in this case); however, catalyst regeneration between 550 and 650°C by heating in air significantly restored the catalyst's textural features and improved the catalytic activity.…”

TG/FT-IR analysis of HZSM5 and HUSY deactivation during the catalytic pyrolysis of polyethylene

“…4 seems to indicate that the degradation process may be more complex with HUSY than that observed with HZSM5. In a previous work [12] it was suggested that under these experimental conditions the degradation mechanism is catalytic at the beginning of the process with HUSYand thermal at the very end. This fact was justified by the textural properties found in HUSY (pore volume, BET and external surface area) and by the coke content determined [12] in a progressively deactivated zeolite.…”

“…1 shows the 3D diagram obtained during the thermal pyrolysis of LDPE. The solid line in the temperature scale indicates the temperature at which the decomposition process starts according to TG data [12]. As can be seen, the gases proceed in a single step.…”

“…In a recent work [12] the catalytic activity of HZSM5 and HUSY over two polyethylene samples of different branching degree by TG have been studied. In that work the catalyst activity was defined in terms of the reduction of the decomposition temperature of the polymer.…”

Using simultaneous DSC/TG to analyze the kinetics of polyethylene degradation—catalytic cracking using HY and HZSM-5 zeolites

“…It allows better control of the hydrocarbon products distribution and reduces the processing temperature, [7,8] resulting in reduced energy consumption. Different studies have been performed using different catalysts, including organometallics [9,10], but mostly with solid acids, and particularly with zeolites [11][12][13][14][15].…”