Correlations between product distribution and feedstock composition in thermal cracking processes for mixed plastic waste

Forero-Franco, Renesteban; Cañete-Vela, Isabel; Berdugo-Vilches, Teresa; González-Arias, Judith; Maric, Jelena; Thunman, Henrik; Seemann, Martin

doi:10.1016/j.fuel.2023.127660

Cited by 12 publications

(2 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…63,74,75 Further reactions (e.g., 1,x-hydrogen shifts in primary radicals) of the initial products may eventually lead to cyclizations and subsequently the formation of hydrogen, aromatics, and finally coke. 46,73,76 Here, we report upon the pyrolysis of several common types of polyethylene using the "Hamburger Verfahren" with nitrogen gas as the medium (one pass). In the past, the operation of a fluidized bed at the ITMC was majorly performed using the pyrolysis gas as the fluidizing medium.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Successive β-scission in midchain radicals will lead to primary alkyl radicals and terminal olefins. Considerations based on these processes lead to the prediction of a mixture of dienes, alkanes, ethylene, and 1-olefins as “simple pathway” products (in a ratio of 1:1: x :2). , The formation of products may also be influenced by mass transport of volatile products and hence be dependent on the dynamics of the polymer (melt), i.e., processes that will scale with densities and viscosities. ,, Further reactions (e.g., 1, x -hydrogen shifts in primary radicals) of the initial products may eventually lead to cyclizations and subsequently the formation of hydrogen, aromatics, and finally coke. ,, …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Fast Pyrolysis Product Analysis of Commercial Polyethylenes

Matthiesen,

Plessing,

Luinstra

2024

Energy Fuels

View full text Add to dashboard Cite

The pyrolysis of eight commercial polyethylene grades in a fluidized bed reactor (FBR, Hamburger Verfahren) operating at 750 °C (residence time of ∼3 s) is carried out to show that the gaseous and liquid product spectra are very similar. The reaction temperature is the sole parameter of major impact for the outcome of the pyrolysis in the FBR between 700 and 800 °C. The temperature of 750 °C gives a good yield of ethylene (31 wt %) and propylene (15 wt %) and moderate amounts of methane (11 wt %). Solid products (soots) are hardly formed. A stochastic analysis shows that the molar amounts of the linear alkane and alkene products with less than 4−5 carbon atoms (making up 75 wt % of the products) are confidently described by geometric distributions Geom(1 − α). The remaining 25 wt % of the products are mainly aromatics with 6 or more carbon atoms. The formation of alkanes at a 750 °C bed temperature is interpreted to result from random chain scission with a probability α of 0.82 in n-alkyls, followed by a hydrogen abstraction: 1-alkenes result from a competition between β-scission and 1,2-hydrogen shifts with an α of 0.64 for β-scission in linear alkyl radicals. The intermediate formation of n-alkyls and primary radicals is key; weak bond scissions (at branching points) are not relevant for polyethylene decomposition at 750 °C. The α geometric parameters are temperature dependent, giving access to activation energies of 47(4) kJ/mol for alkane formation and 54(2) kJ/mol for the difference in β-scission and 1,2-hydrogen shift on the interval between 600 and 900 °C. The geometric distributions suggest that the 75 wt % gaseous products are directly formed and transported away from the hot zone (surface ablation). The same analysis applied to published data on polyethylene pyrolysis shows that different geometric distributions for alkanes and alkenes are present too.

show abstract

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fast Pyrolysis Product Analysis of Commercial Polyethylenes

Matthiesen,

Plessing,

Luinstra

2024

Energy Fuels

View full text Add to dashboard Cite

show abstract

Highly Efficient Recycling Waste Plastic into Hydrogen and Carbon Nanotubes through a Double Layer Microwave‐Assisted Pyrolysis Method

Wang,

Hu,

et al. 2024

Macromol. Rapid Commun.

View full text Add to dashboard Cite

Microwave‐assisted pyrolysis of PE to hydrogen and carbon material has great potential to solve the problem of waste PE induced white pollution and provide a promising way to produce hydrogen energy. To increase the hydrogen yield, a new microwave‐assisted pyrolysis procedure should be developed. In the present study, a facile double‐layer microwave‐assisted pyrolysis (DLMP) method is developed to pyrolyze PE. Within this method, PE can be converted to hydrogen, multiwalled carbon nanotubes with extremely high efficiency compared with the traditional methods. A high hydrogen yield of 66.4 mmol g−1PE is achieved, which is ≈93% of the upper limit of the theoretical hydrogen yield generated from the PE pyrolysis process. The mechanism of high hydrogen yield during the microwave‐assisted pyrolysis of PE using the DLMP method is also clarified in detail. The DLMP method paved the potential way for recycling plastic waste into high‐value‐added products.

show abstract