High-pressure pyrolysis and its mechanism of polyethylene

GU Jing; CHENG Lei-lei; WANG Ya-zhuo; ZHANG Yuan-xiang; YUAN Hao-ran

doi:10.19906/j.cnki.JFCT.2021028

Volume 49 Issue 3

Mar. 2021

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Article Navigation > Journal of Fuel Chemistry and Technology > 2021 > 49(3): 395-406

GU Jing, CHENG Lei-lei, WANG Ya-zhuo, ZHANG Yuan-xiang, YUAN Hao-ran. High-pressure pyrolysis and its mechanism of polyethylene[J]. Journal of Fuel Chemistry and Technology, 2021, 49(3): 395-406. doi: 10.19906/j.cnki.JFCT.2021028

Citation:

GU Jing, CHENG Lei-lei, WANG Ya-zhuo, ZHANG Yuan-xiang, YUAN Hao-ran. High-pressure pyrolysis and its mechanism of polyethylene[J]. Journal of Fuel Chemistry and Technology, 2021, 49(3): 395-406. doi: 10.19906/j.cnki.JFCT.2021028

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High-pressure pyrolysis and its mechanism of polyethylene

doi: 10.19906/j.cnki.JFCT.2021028

GU Jing^{1, 2, 3, 4, 5
,},
CHENG Lei-lei²,
WANG Ya-zhuo^{1, 2, 3, 4, 5},
ZHANG Yuan-xiang²,
YUAN Hao-ran^{1, 2, 3, 4, 5
,
,}

1.
Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences (CAS), Guangzhou 510640, China
2.
Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
3.
CAS Key Laboratory of Renewable Energy, Guangzhou 510640, China
4.
Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China
5.
Foshan Kehengbo Environmental Protection Technology Co. LTD, Foshan 528200, China

Funds: The project was supported by the National Key Research and Development Program of China (2018YFC1901200), National Natural Science Foundation of China (51976223) and Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) （GML2019ZD0101）.

Received Date: 2020-10-21
Rev Recd Date: 2020-11-27

Available Online: 2021-03-19

Publish Date: 2021-03-19

Abstract

Abstract

With the increasing waste disposal problems, high-value utilization technology using less energy is important to incentivize better recycling of plastic waste. Polyethylene high-pressure thermal cracking and catalytic pyrolysis experiments were conducted at a set temperature of 380 ℃ and low initial pressures (1−5) × 10⁵ Pa. The process temperature curves were recorded and the hydrocarbon distribution of products was analyzed. The results suggest that the phase state in the pyrolysis system is a critical issue for reaction pathways. Thus, the pressure changes have different effects on the thermal cracking and catalytic pyrolysis of polyethylene. There is a phenomenon of thermal runaway during the polyethylene high-pressure pyrolysis process. The peak temperature represents a monotonous increase with the increasing initial pressure; the higher peak temperature leads to deeper cracking of polyethylene, giving more low-molecular-weight products. In the high-pressure catalytic pyrolysis experiments under the same other conditions, no thermal runaway is observed. The Zn-supported ZSM-5 catalyst converts polyethylene into aromatics, and the selectivity for monocyclic aromatics in the liquid phase is up to 82.53%. Moreover, the coke yield is less than 1.5%.
- polyethylene,
- high pressure,
- thermal cracking,
- catalytic pyrolysis,
- thermal runaway

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References(29)

References

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