Catalyst Deactivation

Figueiredo, Joana; Ribeiro, F. Ramôa

doi:10.1007/978-94-011-4329-5_5

Cited by 3 publications

(2 citation statements)

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“…These techniques are used for elemental analysis but can also provide relevant data on the adsorbed species. As an example, Chen et al used a combination of 13 C NMR, FTIR and UV-Vis to characterize coke formed over a Y-zeolite during catalytic pyrolysis of PE [65]. Deconvolution of NMR spectra provided them with a very precise description of coke nature (aliphatic, aromatic), amount, and repartition.…”

Section: Structural and Physical Propertiesmentioning

confidence: 99%

“…However, similarly to many other catalytic processes, industrial application of plastic waste catalytic pyrolysis is hindered by fast deactivation of catalysts. The science of catalyst deactivation has been steadily developed and its literature has expanded over the years, including books [13,14], comprehensive reviews [15][16][17], as well as many papers and topical journal issues [18][19][20][21][22]. Most of them indicate that formation of coke is a very common deactivation pathway in industrial processes involving organic compounds in the presence of heterogeneous catalysts.…”

Section: Introductionmentioning

confidence: 99%

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Deactivation and Regeneration of Zeolite Catalysts Used in Pyrolysis of Plastic Wastes—A Process and Analytical Review

2021

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In catalytic industrial processes, coke deposition remains a major drawback for solid catalysts use as it causes catalyst deactivation. Extensive study of this phenomenon over the last decades has provided a better understanding of coke behavior in a great number of processes. Among them, catalytic pyrolysis of plastics, which has been identified as a promising process for waste revalorization, is given particular attention in this paper. Combined economic and environmental concerns rose the necessity to restore catalytic activity by recovering deactivated catalysts. Consequently, various regeneration processes have been investigated over the years and development of an efficient and sustainable process remains an industrial challenge. Coke removal can be achieved via several chemical processes, such as oxidation, gasification, and hydrogenation. This review focuses on oxidative treatments for catalyst regeneration, covering the current progress of oxidation treatments and presenting advantages and drawbacks for each method. Molecular oxidation with oxygen and ozone, as well as advanced oxidation processes with the formation of OH radicals, are detailed to provide a deep understanding of the mechanisms and kinetics involved (direct and indirect oxidation, reaction rates and selectivity, diffusion, and mass transfer). Finally, this paper summarizes all relevant analytical techniques that can be used to characterize deactivated and regenerated solid catalysts: XRD, N2 adsorption-desorption, SEM, NH3-TPD, elemental analysis, IR. Analytical techniques are classified according to the type of information they provide, such as structural characteristics, elemental composition, or chemical properties. In function of the investigated property, this overall tool is useful and easy-to-use to determine the adequate analysis.

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Section: Structural and Physical Propertiesmentioning

confidence: 99%