Open Access

ARTICLE

Molecular Dynamics-Based Simulation of Polyethylene Pipe Degradation in High Temperature and High Pressure Conditions

Guowei Feng¹, Qing Li^2,3, Yang Wang^1,*, Nan Lin⁴, Sixi Zha¹, Hang Dong¹, Ping Chen⁵, Minjun Zheng⁶

1 School of Mechanical Engineering, Xinjiang University, Urumqi, 830046, China
2 Xinjiang Yian Special Inspection Engineering Company Limited, Urumqi, 830063, China
3 Xinjiang Uygur Autonomous Region Inspection Institute of Special Equipment, Urumqi, 830000, China
4 Pressure Pipe Department, China Special Equipment Inspection and Research Institute, Beijing, 100013, China
5 Tarim Oilfield Branch Company, Korla, 841000, China
6 Yimai Cai Oil and Gas Management Area, Tarim Oilfield Branch Office, Korla, 841000, China

* Corresponding Author: Yang Wang. Email:

(This article belongs to the Special Issue: Computational Mechanics and Fluid Dynamics in Intelligent Manufacturing and Material Processing Ⅱ)

Fluid Dynamics & Materials Processing 2024, 20(9), 2139-2161. https://doi.org/10.32604/fdmp.2024.053941

Received 14 May 2024; Accepted 25 June 2024; Issue published 23 August 2024

Abstract

High-density polyethylene (HDPE) pipes have gradually become the first choice for gas networks because of their excellent characteristics. As the use of pipes increases, there will unavoidably be a significant amount of waste generated when the pipes cease their operation life, which, if improperly handled, might result in major environmental contamination issues. In this study, the thermal degradation of polyethylene materials is simulated for different pressures (10, 50, 100, and 150 MPa) and temperatures (2300, 2500, 2700, and 2900 K) in the framework of Reactive Force Field (ReaxFF) molecular dynamics simulation. The main gas products, density, energy, and the mean square displacement with temperature and pressure are also calculated. The findings indicate that raising the temperature leads to an increase in the production of gas products, while changing the pressure has an impact on the direction in which the products are generated; the faster the temperature drops, the less dense the air; both temperature and pressure increase impact the system’s energy conversion or distribution mechanism, changing the system’s potential energy as well as its total energy; the rate at which molecules diffuse increases with temperature, and decreases with pressure. The results of this investigation provide a theoretical basis for the development of the pyrolytic treatment of polyethylene waste materials.

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Keywords

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