Upgrading of polyethylene to hydrocarbon fuels over the Fe-modified Pt/Al2O3 catalysts at a mild condition without external H2

Chen, Zezhou; Xu, Linlin; Zhang, Xurui

doi:10.1016/j.cej.2022.136213

Cited by 14 publications

(12 citation statements)

References 79 publications

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“…These products are valuable as lubricants and detergent precursors, and are currently produced through more energy-intensive routes . Adding a small amount of iron to the catalyst has been shown to further increase the yield of aromatics . A technoeconomic assessment for this type of polymer conversion has not been published as of this writing, but the catalyst will undoubtedly be a cost driver given the low polymer/catalyst ratios and energy-intensive catalyst regeneration procedures detailed in the literature.…”

Section: Introductionmentioning

confidence: 99%

“…19 Adding a small amount of iron to the catalyst has been shown to further increase the yield of aromatics. 21 A technoeconomic assessment for this type of polymer conversion has not been published as of this writing, but the catalyst will undoubtedly be a cost driver given the low polymer/catalyst ratios and energy-intensive catalyst regeneration procedures detailed in the literature. Lowering catalyst costs and increasing efficiency are paramount to moving the technology forward.…”

Section: ■ Introductionmentioning

confidence: 99%

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Activity of Silica-Alumina for the Conversion of Polyethylene into Tunable Aromatics Below Pyrolytic Temperatures

Pennel,

Maurya,

Ebrahim

et al. 2023

ACS Sustainable Chem. Eng.

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Plastic waste is a mounting problem that lacks global strategy, largely due to inadequate recycling capabilities. One alternative gaining traction in the heterogeneous catalysis community is the upcycling of polyolefins into value-added products, such as hydrogen-free conversion to alkylaromatic compounds over Pt/Al2O3. Here, we examined the activity of nominally metal-free, mesoporous silica-alumina mixed oxide materials (SiO2–Al2O3) for the conversion of polyethylene into aromatic compounds at temperatures of and below 280 °C. Yields with the silica-alumina catalysts are comparable to those obtained over Pt(1 wt %)/Al2O3 under identical conditions, and product selectivity can be tuned by altering reaction conditions or the acid site density of the SiO2–Al2O3. Notably, the fraction of polyaromatic products increases with the Brønsted acid site density of the catalyst, as does the degree of polymer deconstruction. These catalysts can be reused without regeneration, and their activity improves with each recycling event, producing soluble product yields up to 83%. Preliminary work on the mechanism of the reaction suggests that acid sites are responsible for initiating depolymerization and aromatization reactions, in analogy to previous work in the literature. This work showcases the activity of SiO2–Al2O3 for polyolefin deconstruction/aromatization at subpyrolytic temperatures and lays the foundation for future studies involving solid acid and bifunctional catalysts.

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Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Activity of Silica-Alumina for the Conversion of Polyethylene into Tunable Aromatics Below Pyrolytic Temperatures

Pennel,

Maurya,

Ebrahim

et al. 2023

ACS Sustainable Chem. Eng.

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“…First, the Lewis acid sites of Fe 2 O 3 were partially weakened, since the lattice oxygen was removed by the reaction with the light hydrocarbons, meanwhile producing CO and CO 2 . Secondly, the microporous structure of Al 2 O 3 could facilitate the dehydrogenation and aromatic reactions, which promotes the formation of aromatic hydrocarbons and catalytic coke . As for combinative catalysts, Fe 2 O 3 + Al 2 O 3 and Al 2 O 3 + Fe 2 O 3 both exhibited slightly higher hydrogen yields than solo catalysts did.…”

Section: Resultsmentioning

confidence: 99%

Synergistic Activity of the Fe₂O₃/Al₂O₃ Catalyst for Hydrogen Production through Pyrolysis-Catalytic Decomposition of Plastics

Xue

Lin

et al. 2023

ACS Sustainable Chem. Eng.

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Plastic recycling through thermochemical conversion for the production of fuels and chemicals is a promising way for simultaneous waste processing and utilization. In the current study, high-density polyethylene (HDPE) was subjected to pyrolysis and then catalytic upgrading to produce hydrogen in the presence of a novel Fe2O3/Al2O3 catalyst with a grain boundary. To understand the catalyst–support interaction as well as the resulting synergistic catalytic effects, catalytic pyrolysis of HDPE with supported Fe2O3/Al2O3 was compared with those over Fe2O3, Al2O3, and a cascade combination of both. It was found that the performance of Fe2O3/Al2O3 was superior to that of other catalysts in terms of chain cracking and C–C/C–H bond cleavage. The hydrogen yield with Fe2O3/Al2O3 was 50.53 mmol·gplastic –1, equivalent to more than 70% of hydrogen in plastic. Besides, alkanes/alkenes ranging from C2 to C9 dominated the hydrocarbon products. The analysis of the cycle performance revealed that the reduction pathway of Fe2O3/Al2O3 was different from those of other Fe2O3-containing catalysts, which was also confirmed by temperature-programmed reduction. To investigate the essential role and reaction mechanism with Fe2O3/Al2O3, characterizations of Fe2O3/Al2O3 before and after the reaction were conducted. The grain boundary between Fe2O3 and Al2O3 enhanced the adsorption of gaseous products. More importantly, the catalyst–support interaction to form FeAl2O4 during the pyrolysis reaction, determined by X-ray photoelectron spectroscopy, was responsible for effective proton adsorption and C–H bond cleavage. This study provides an insightful understanding of catalyst transformation during plastic catalytic pyrolysis for hydrogen production.

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“…With a small amount of Fe species (Fe/Pt = 0.25), the Pt–Fe/Al 2 O 3 catalyst shows the best performance in conversion of PE to fuel oils in a moderate yield of 55.6%. 67 The oil contains mainly linear C 7 –C 19 alkanes and alkenes with a small fraction of alkylaromatics. This is quite different from the case reported by Zhang, where long-chain alkylaromatics and alkylnaphthenes are the primary products in the oil.…”

Section: Catalytic Hydroconversion Processes For Deconstruction Of Po...mentioning

confidence: 99%

Catalytic hydroconversion processes for upcycling plastic waste to fuels and chemicals

Wei¹,

Liu²,

Zeng³

et al. 2023

Catal. Sci. Technol.

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Upgrading of polyethylene to hydrocarbon fuels over the Fe-modified Pt/Al2O3 catalysts at a mild condition without external H2

Cited by 14 publications

References 79 publications

Activity of Silica-Alumina for the Conversion of Polyethylene into Tunable Aromatics Below Pyrolytic Temperatures

Activity of Silica-Alumina for the Conversion of Polyethylene into Tunable Aromatics Below Pyrolytic Temperatures

Synergistic Activity of the Fe₂O₃/Al₂O₃ Catalyst for Hydrogen Production through Pyrolysis-Catalytic Decomposition of Plastics

Catalytic hydroconversion processes for upcycling plastic waste to fuels and chemicals

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Upgrading of polyethylene to hydrocarbon fuels over the Fe-modified Pt/Al2O3 catalysts at a mild condition without external H2

Cited by 14 publications

References 79 publications

Activity of Silica-Alumina for the Conversion of Polyethylene into Tunable Aromatics Below Pyrolytic Temperatures

Activity of Silica-Alumina for the Conversion of Polyethylene into Tunable Aromatics Below Pyrolytic Temperatures

Synergistic Activity of the Fe2O3/Al2O3 Catalyst for Hydrogen Production through Pyrolysis-Catalytic Decomposition of Plastics

Catalytic hydroconversion processes for upcycling plastic waste to fuels and chemicals

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Synergistic Activity of the Fe₂O₃/Al₂O₃ Catalyst for Hydrogen Production through Pyrolysis-Catalytic Decomposition of Plastics