Kinetic modelling of high density polyethylene pyrolysis: Part 1. Comparison of existing models

Abstract

High Density Poly-Ethylene (HDPE) is one of the possible solid fuels to be used in hybrid 5 rocket propulsion, despite its low ability of rapidly producing combustible gas. This 6 drawback may be balanced by the auto-ignition delay of the pyrolysis products, which would 7 conduct to the increase of the heat release rate in the engine and thus to the one of the 8 regression rate. Six single and multi steps HDPE pyrolysis mechanisms from the literature 9 are compared in this paper to determine their ability to predict the production of by-10 products and the consumption of HDPE. Transient pyrolysis is observed from 650 K to 11 823 K at atmospheric pressure and discrepancies up to a factor 7 are found between these 12 mechanisms, despite they are all derived from experimental data. One mechanism is finally 13 selected to conduct a parametric study in more realistic operating conditions for hybrid 14 rocket, up to 1700 K and 100 bar. Identifying and quantifying pyrolysis products are 15 necessary to study their combustion with another detailed mechanism. 16

Realizing the Potential High Benefits of Circular Economy in the Chemical Industry: Ethylene Monomer Recovery via Polyethylene Pyrolysis

“…To close materials loops in the chemical industry through circular economy strategies, the role of this technology needs to be projected, scaled and integrated. Some attempts to model the pyrolysis of PE include the development of kinetic models 25 and process simulations 26 . However, a further technical, economic and environmental analysis is still required to assess the implications of industrializing this process.…”

“…Some attempts to model the pyrolysis of PE include the development of kinetic models and process simulations . However, a further technical, economic, and environmental analysis is still required to assess the implications of industrializing this process.…”

Oxidation of crystalline polyethylene

“…(random scission). At high temperature under pyrolytic conditions, PE undergoes both backbiting and random scission pathways [6,[13][14][15][16]. The overall relatively high activation energy for the inert decomposition of PE (150-260 kJ/mol) is linked to a limiting step characterised by the initial random scission [6,12,[17][18][19][20].…”

Chemical Recycling of Polyolefins (PE, PP): Modern Technologies and Products

“…• random scission -intermolecular transfer of hydrogen atom and then β-scission in the middle part of the molecule with the creation of products with shorter chains (Figure 2) [8].…”