Study on the decomposition mechanism of supercritical ethylene during ultra-high pressure polymerization process

Chen Yao; Zhang Zhichen; Zhu Yunfeng; Chen Haowen; Song Yifan; Zhang Ruiyi; Shi Xiaogang; Sun Bing; Xu Wei

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Study on the decomposition mechanism of supercritical ethylene during ultra-high pressure polymerization process

Updated：2026-05-14

- Study on the decomposition mechanism of supercritical ethylene during ultra-high pressure polymerization process
- Chinese Journal of Chemical Engineering Vol. 90, Issue 2, Pages: 146-156(2026)
- Affiliations：
  
  State Key Laboratory of Chemical Safety, Qingdao 266000, China
  SINOPEC Research Institute of Safety Engineering Co., Ltd. Qingdao 266000, China
  National Registration Center for Chemicals, Ministry of Emergency Management, Qingdao 266000, China
  College of Chemical Engineering and Environment, China University of Petroleum (Beijing), Beijing 102249, China
- Author bio：
  
  These authors contributed equally to this work.
  Corresponding authors. E-mail addresses: sunb.qday@sinopec.com (B. Sun)
  Corresponding authors. xuw.qday@sinopec.com (W.Xu).
- Funds：
- DOI：
  CLC：
- Received：27 June 2025，
  
  Revised：2025-09-28，
  
  Accepted：28 September 2025，
  
  Online First：27 November 2025，
  
  Published：2026-02
- Accepted：
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Chen Yao, Zhang Zhichen, Zhu Yunfeng, et al. Study on the decomposition mechanism of supercritical ethylene during ultra-high pressure polymerization process[J]. Chinese Journal of Chemical Engineering, 2026, 90(2): 146-156.
DOI：

Chen Yao, Zhang Zhichen, Zhu Yunfeng, et al. Study on the decomposition mechanism of supercritical ethylene during ultra-high pressure polymerization process[J]. Chinese Journal of Chemical Engineering, 2026, 90(2): 146-156. DOI：

摘要

Abstract

In the production of low density polyethylene (LDPE)

the presence of oxygen may induce the decomposition of supercritical ethylene

thereby affecting the stability of equipment operation and potentially leading to safety hazards. This study investigated the inducing and promoting effects of oxygen on the runaway decomposition of supercritical ethylene. The reaction mechanism of oxygen-induced supercritical ethylene was explored through ReaxFF molecular dynamics

simulation

and the reaction network was systematically constructed. It was found that the minimum oxygen concentration required to initiate ethylene decomposition at 240℃ and 240 MPa was 0.0042% (mass). The coupling of oxygen and ethylene to form the intermediate C

O· promoted the cleavage of the C—C bond in ethylene. Under the condition of oxygen absence

ethylene mainly underwent polymerization reactions. As the oxygen concentration increased

unstable intermediates such as C

O· were generated

and the dominant reaction pathway of ethylene shifted from polymerization to decomposition. This study provided a theoretical basis for understanding the oxygen induced supercritical ethylene decomposition in low density polyethylene process.

关键词

Keywords

references

Y. Gao, Y. Yao, H. Li, J. Dong, Review and prospect of polyethylene mark et development at home and abroad, Sino-Global Energy 27 (2022) 58—63. (in Chinese)

H.J. Lee, Y.K. Yeo, J.Y. Changn, Modeling of industrial high pressure autoclave polyethylene reactor including decomposition phenomena, Kor. J. Chem. Eng. 17 (2)(2000)223—229.

Z.C. Zhang, W. Xu, Y.F. Zhu, S.T. Ma, Y.H. Li, J. Jiang, Z. Yang, W.S. Cheng, Z.C. Zhou, B. Sun, The decomposition mechanism of ethylene and modeling simulation during LDPE production: a comprehensive review and perspectives, J. Anal. Appl. Pyrolysis 175 (2023) 106199.

Y.C. Cheng, S.C. Chang, C.M. Shu, Effects of volatile organic compounds on the explosion characteristics of polyethylene dust, Process Saf. Environ. Prot. 168 (2022)114—122.

G. Luft, R. Neumann, Selbstzerfall und fremdgezündeter zerfall von verdichtetem äthylen, Chem. Ing. Tech. 50 (8) (1978) 620—622.

D.I. Shannon, Relief device sizing for ethylene decompositions: high pressure polyethylene industry, Process Saf. Prog. 27(1)(2008)35—40.

O. Ashrafi, N. Mostoufi, R. Sotudeh-Gharebagh, Two phase steady-state particle size distribution in a gas-phase fluidized bed ethylene polymerization reactor, Chem. Eng. Sci. 73 (2012) 1—7.

S.X. Zhang, N.K. Read, W.H. Ray, Runaway phenomena in low-d ensity polyethylene autoclave reactors, AIChE J. 42 (10) (1996) 2911—2925.

Y. Fei, B. Sun, F. Zhang, W. Xu, N. Shi, J. Jiang, Inherently safer reactors and procedures to prevent reaction runaway, Chin. J. Chem. Eng. 26 (6) (2018) 1252—1263.

Y.N. Yang, J. Jin, L.T. Zhu, Y.N. Zhou, Z.H. Luo, Runaway criteria for predicting the thermal behavior of chemical reactors, Curr. Opin. Chem. Eng. 43(2024)100986.

X.Q. Fan, J.Y. Sun, J.D. Wang, Z.L. Huang, Z.W. Liao, G.D. Han, Y.R. Yang, Scaleup and thermal stability analysis of fluidized bed reactors for ethylene polymerization, Chin. J. Chem. Eng. 62 (2023) 281—290.

J. Albert, G. Luft, Runaway phenomena in the ethylene/vinylacetate copolymerization under high pressure, Chem. Eng. Process. Process. Intensif. 37 (1) (1998) 55—59.

J.C. Wang, Cause analysis and countermeasures of ethylene decomposition in high pressure polyethylene plant, Knowl. Econ. 15 (2013) 72—73. (in Chinese)

N.H. Kolhapure, R.O. Fox, A. Daiβ, F.O. Mähling, PDF simulations of ethylene decomposition in tubular LDPE reactors, AIChE. J. 51 (2) (2005) 585—606.

L. Bao, Cause analysis and control measures for decomposition reactions in LDPE plant, Sino-Global Energy 25 (2020)79—82. (in Chinese)

M.X. Zhou, F.W. Yan, X.L. Zhong, L. Xu, Y. Wang, Sooting characteristics of partially-premixed flames of ethanol and ethylene mixtures: unravelling the opposing effects of ethanol addition on soot formation in non-premixed and premixed flames, Fuel 291(2021)120089.

L. Song, C.C. Xu, J. Ye, Y. Zhang, B. Chen, F.C. Hou, B.C. Chen, H.L. Su, J. Sun, Pyrolysis and oxidation mechanisms of ethylene and ethanol blended fuel based on ReaxFF molecular dynamics simulation, Fuel 373(2024)132361.

J.H. Martin, B. Akih-Kumgeh, Reactive molecular dynamics simulation of methane-oxygen autoignition at high-pressure conditions, Int. J. Chem. Kinet. 57(11)(2025)662—673.

Z.J. Chen, W.Z. Sun, L. Zhao, High-temperature and high-pressure pyrolysis of hexadecane: molecular dynamic simulation based on reactive force field (ReaxFF), J. Phys. Chem. A 121(10)(2017)2069—2078.

B. Wang, C.C. Wang, B.L. Lv, Comparative analysis on safety of polyethylene production process by high pressure method and low pressure method, Ind. Des. 9(2011)156.

K. Yamada, S. Kumagai, T. Shiratori, T. Kameda, Y. Saito, A. Watanabe, C. Watanabe, N. Teramae, T. Yoshioka, Combined UV-irradiation and pyrolysis-GC/MS approach for evaluating the deterioration behavior of ethylene vinyl acetate, Polym. Degrad. Stab. 190(2021)109623.

Y. Chen, Z.C. Zhang, Y.F. Zhu, X.G. Shi, B. Sun, W. Xu, Research on the explosion behavior and flame evolution characteristics of LDPE powder with different sizes, Process. Saf. Environ. Prot. 195 (2025) 106735.

C.A. Gunawardana, A. Kong, D.O. Blackwood, C. Travis Powell, J.F. Krzyzaniak, M.C. Thomas, C. Calvin Sun, Magnesium stearate surface coverage on tablets and drug crystals: insights from SEM-EDS elemental mapping, Int. J. Pharm. 630(2023)122422.

Z.C. Zhang, E.Q. Yu, Y.J. Liu, F.S. Wen, N. Shi, H. Du, Z.J. Chen, Z.C. Wang, D. Liu, The effect of composition change and allocation in raw material on the carbonaceous structural evolution during calcination process, Fuel 309 (2022)122173.

S. Na, H. Jeong, I. Kim, S.M. Hong, J. Shim, I.H. Yoon, K.H. Cho, Distribution coefficient prediction using multimodal machine learning based on soil adsorption factors, XRF, and XRD spectrum data, J. Hazard. Mater. 478(2024) 135285.

Z.C. Zhang, Y. Chen, Y.F. Zhu, Y.H. Li, S.T. Ma, H.W. Chen, Z.Q. He, H.C. Bao, J. Jiang, B. Sun, W. Xu, Decomposition behavior of supercritical ethylene under ultra-high temperature and ultra-high pressure, J. Anal. Appl. Pyrolysis 181 (2024)106654.

Y. Chen, Z.C. Zhang, Y.F. Zhu, Y.H. Li, S.T. Ma, H.W. Chen, J. Jiang, B. Sun, W. Xu, Investigation on the effect of carbon powder structural characteristics derived from ethylene decomposition on powde r explosion, Thermochim. Acta 742(2024)179895.

Z.C. Zhang, Z.H. Wang, L.J. Zhang, J.J. Cui, S.H. Guo, H.H. Ji, Y.J. Liu, G.L. Zhao, W. Zhu, C. Jiao, Y.G. Cao, D. Liu, Study on the co-carbonization behavior of high-temperature coal tar pitch and raffinate oil of low-temperature coal tar, Fuel 310(2022)122469.

Y.B. Wang, S.J. Yao, W. Wang, C.L. Qiu, J. Zhang, S.W. Deng, H. Dong, C. Wu, J. G. Wang, Pyrolysis of vulcanized styrene-butadiene rubber via ReaxFF molecular dynamics simulation, Chin. J. Chem. Eng. 31 (2021) 94—102.

J.T. Cai, Q.F. Huang, H. Chen, T. Zhang, B. Niu, Y.Y. Zhang, D.H. Long, Evaluating two stages of silicone-containing arylene resin oxidation via experiment and molecular simulation, Chin. J. Chem. Eng. 66(2024)189—202.

C. Ashraf, A.C.T. van Duin, Extension of the ReaxFF combustion force field toward syngas combustion and initial oxidation kinetics, J. Phys. Chem. A 121 (5)(2017)1051—1068.

D. Hibbitts, M. Neurock, Promotional effects of chemisorbed oxygen and hydroxide in the activation of C—H and O—H bonds over transition metal surfaces, Surf. Sci. 650(2016)210—220.

B. Xing, G.C. Wang, Insight into the general rule for the activation of the X-H bonds (X = C, N, O, S) induced by chemisorbed oxygen atoms, Phys. Chem. Chem. Phys. 16(6)(2014) 2621—2629.

B. Xing, X.Y. Pang, G.C. Wang, C—H bond activation of methane on clean and oxygen pre-covered metals: a systematic theoretical study, J. Catal. 282 (1) (2011)74—82.

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