Update to “Effect of Temperature and Vapor Residence Time on the Micropyrolysis Products of Waste High Density Polyethylene”

Abstract

A previously published paper presented product composition results in peak area percentage following pyrolysis of waste highdensity polyethylene experiments in a two-stage micropyrolysis reactor.

Expanding Plastics Recycling Technologies: Chemical Aspects, Technology Status and Challenges

“…261 In PE pyrolysis, early studies showed that only liquid and gas -no wax -are produced above 600 ºC. 265 Increasing temperature leads to increased aromatic production, as gas is converted to aromatics through a Diels-Alder reaction and unimolecular cyclization reactions, [266][267] although a study by Kulas et al 263 showed that the reaction pathway from gas to aromatics has low temperature dependence.…”

Micropyrolysis of Polyethylene and Polypropylene Prior to Bioconversion: The Effect of Reactor Temperature and Vapor Residence Time on Product Distribution

“…This means that these reaction pathways have a very low temperature dependence. This is unexpected for k 10 , as the literature shows that increasing temperature has a significant positive effect on aromatic production. , …”

“…Going from 550 to 600 °C increased the gas yield from 20 to 30 wt %. Further increases of the reactor temperature up to 675 °C have been found to increase the gas yield up to 80 wt % at a VRT of 1.4 s for waste HDPE . Similar to gas production, aromatic production is also favored at high reaction temperatures (>600 °C).…”

“…Increasing the residence time increases the conversion of high molecular weight primary pyrolysis products to low molecular weight liquid hydrocarbons and noncondensable hydrocarbon gases. , High temperatures and long residence times have been found to be the best conditions for maximizing hydrocarbon gas production and also for aromatics production in the pyrolysis process. , Random chain scission has been proposed as the dominant thermal degradation mechanism, which leads to the formation of a large number of hydrocarbon species. , The stabilization of the resultant radical after chain scission leads to the formation of carbon–carbon double bonds (CC) in the structure as well as the production of alkanes . Previous research on the pyrolysis of PP and PE shows that waxes and heavy oil olefins are produced at low temperatures with gases and light oils at high temperatures. , In one study, fast pyrolysis of waste HDPE at a temperature of 625 °C produced 30 wt % light oil and 60 wt % gases …”

Expanding Plastics Recycling Technologies: Chemical Aspects, Technology Status and Challenges

“…In PE pyrolysis, early studies showed that only liquid and gas -no wax -are produced above 600 ºC. 246 Increasing temperature leads to increased aromatic production, as gas is converted to aromatics through a Diels-Alder reaction and unimolecular cyclization reactions, [247][248] although a study by Kulas et al 249 showed that the reaction pathway from gas to aromatics has low temperature dependence.…”