Comparative study of continuous-stirred and batch microwave pyrolysis of linear low-density polyethylene in the presence/absence of HZSM-5

Li, Fan; Liu, Lei; Xiao, Zhiguo; Su, Zheyang; Huang, Pei; Peng, Hongyu; Lv, Sen; Jiang, Haiwei; Ruan, Roger; Chen, Paul

doi:10.1016/j.energy.2021.120612

Cited by 49 publications

(19 citation statements)

References 47 publications

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“…Since polyolefins are long-chain hydrocarbon molecules, all of the long-chain carbenium ion intermediates formed from an alkane or alkene will undergo skeletal rearrangement and β-scissions many times until sufficiently low molecular weight hydrocarbon products are obtained, similar to the case of thermal pyrolysis. In addition to this random scission mode, the branches of a polyolefin molecule could proceed through end-chain scission as well, directly forming low-molecular-weight products as a result. − …”

Section: Reaction Mechanism For Pyrolysis and Catalytic Pyrolysismentioning

confidence: 99%

Understanding the Structure–Activity Relationships in Catalytic Conversion of Polyolefin Plastics by Zeolite-Based Catalysts: A Critical Review

Dong

Liu

et al. 2022

ACS Catal.

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Polyolefins, the largest used commodity plastics in the world, find extensive application in many fields. However, most end up in landfills or incineration, leading to severe ecological crises, environmental pollution, and serious resource waste problems. As representatives on chemical upcycling of polyolefin plastics polyolefin waste to fuels and bulk/fine chemicals, polyolefin catalytic cracking and hydrocracking based on zeolite or metal/zeolite composite catalysts are considered the most effective paths due to their large capacity and strong adaptability to existing petrochemical equipment. After an overview of the reaction mechanisms of pyrolysis and catalytic cracking, this review aims to comprehensively discuss the influence of zeolite catalyst structure (acidity, pore structure, and morphology) on the catalytic activity, selectivity, and stability of polyolefin cracking, particularly emphasizing the importance for matching acidity and pore structure for target product formation. Subsequently, the structure–activity relationship between the metal site and zeolite’s acid site in polyolefin hydrocracking is also discussed. In the end, emerging opportunities and challenges are proposed to promote a more efficient way for polyolefin chemical upcycling.

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Section: Reaction Mechanism For Pyrolysis and Catalytic Pyrolysismentioning

confidence: 99%

Understanding the Structure–Activity Relationships in Catalytic Conversion of Polyolefin Plastics by Zeolite-Based Catalysts: A Critical Review

Dong

Liu

et al. 2022

ACS Catal.

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“…Zhou and co-workers 214 performed pyrolysis of LLDPE in a continuously stirred and batch microwave reactor under similar conditions, and their performances were compared. Interestingly, the selectivity was high for C 14 −C 20 hydrocarbons under continuously stirred conditions, whereas batch pyrolysis provided higher selectivity toward gaseous products including methane as a major fraction.…”

Section: Polypropylene (Pp)mentioning

confidence: 99%

Thermochemical Recycling of Waste Plastics by Pyrolysis: A Review

et al. 2021

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The increasing demand for plastics for their widespread applications has ultimately resulted in accumulation of substantial plastic waste, which remains a concern due to limited efforts, inadequacy, and environmental distresses of conventional techniques for waste plastics remediation. The enhanced production of raw materials for polymer syntheses has a dual impact on our ecosystem by causing rapid depletion of nonrenewable petroleum resources and waste generation. To address this situation, researchers have adopted advanced thermochemical recycling processes to produce intermediate products of the petrochemical industries including monomers, fuels, and other value-added products. Such practices can potentially serve the purpose of a circular economy. This review aims to cover the recent highlights in the field of waste plastics pyrolysis including critical observations from the past to provide precise understanding. Consequently, the reactivities and product distributions for plastic feeds, pyrolysis reactors, roles of catalysts, and effects of operating parameters on reactivity and selectivity have been covered. Coprocessing of plastic waste with radioactive materials, biomass, and heavy petroleum residue is also discussed. Furthermore, an overview on kinetics and mechanistic aspects of plastic pyrolysis is presented with a discussion on relevant analytical techniques. The applications of pyrolysis oil as a fuel or fuel additive are comprised in a separate section. Lastly, comparisons of existing chemical recycling technologies, summaries of commercial operations, and future projections are provided.

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“…GC‐MS analysis showed that linear alkanes (>C 12 ) chains were dominant, and a 1‐alkene fraction was also observed. The Diels‐Alder reactions of the olefines (dienes and dienophiles) also take place to form aromatic compounds from the LDPE and HDPE pyrolysis [192] …”

Section: Depolymerization and Pyrolysis Reaction Mechanismsmentioning

confidence: 99%

“…[97] A recent study by Fan et al used continuous-stirred microwave pyrolysis (CSMP) and a batch microwave system for the pyrolysis of linear LDPE (LLDPE) in the presence and absence of HZSM-5. [98] Using CSMP, long hydrocarbons (C 14 À C 20 ) are obtained selectively. In contrast, using the batch system, more gaseous products (CH 4 ) are produced.…”

Section: Use Of Catalystsmentioning

confidence: 99%

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Recent Trends in the Pyrolysis of Non‐Degradable Waste Plastics

2021

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Waste plastics are non‐degradable constituents that can stay in the environment for centuries. Their large land space consumption is unsafe to humans and animals. Concomitantly, the continuous engineering of plastics, which causes depletion of petroleum, poses another problem since they are petroleum‐based materials. Therefore, energy recovering trough pyrolysis is an innovative and sustainable solution since it can be practiced without liberating toxic gases into the atmosphere. The most commonly used plastics, such as HDPE, LDPE (high‐ and low‐density polyethylene), PP (polypropylene), PS (polystyrene), and, to some extent, PC (polycarbonate), PVC (polyvinyl chloride), and PET (polyethylene terephthalate), are used for fuel oil recovery through this process. The oils which are generated from the wastes showed caloric values almost comparable with conventional fuels. The main aim of the present review is to highlight and summarize the trends of thermal and catalytic pyrolysis of waste plastic into valuable fuel products through manipulating the operational parameters that influence the quality or quantity of the recovered results. The properties and product distribution of the pyrolytic fuels and the depolymerization reaction mechanisms of each plastic and their byproduct composition are also discussed.

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Comparative study of continuous-stirred and batch microwave pyrolysis of linear low-density polyethylene in the presence/absence of HZSM-5

Cited by 49 publications

References 47 publications

Understanding the Structure–Activity Relationships in Catalytic Conversion of Polyolefin Plastics by Zeolite-Based Catalysts: A Critical Review

Understanding the Structure–Activity Relationships in Catalytic Conversion of Polyolefin Plastics by Zeolite-Based Catalysts: A Critical Review

Thermochemical Recycling of Waste Plastics by Pyrolysis: A Review

Recent Trends in the Pyrolysis of Non‐Degradable Waste Plastics

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