Chemical Recycling of Polyolefins with the Molten Metal Reactor at 460 °C

Abstract

This paper describes the pyrolysis of high‐density polyethylene (HDPE) in a molten metal reactor, where the HDPE is initially in direct contact with molten metal at 460 °C. Due to the equal temperature across the molten metal, secondary reactions are minimised, and long‐chain waxes with boiling points over 600 °C accumulate on the molten metal. Once enough wax has accumulated, further HDPE pyrolysis occurs within the wax in a direct heat transfer reaction.

High Molecular Weight Product Formation in Polyolefin Chemical Recycling: A Comprehensive Review on Primary and Secondary Products

“…In another study, a molten metal reactor was employed to convert HDPE, where tin was melted at 460 °C . The introduction of plastics led to the formation of heavy waxes; once enough waxes accumulated in the reactor, plastic pyrolysis occurred in the wax phase itself.…”

“…Wax products comprised chain lengths ranging from C21 to C100, with the majority toward the higher range. However, no information regarding the yields was given for the waxes or other formed products . Another successful reactor technology is the auger reactor, which, in the work of Al-Salem, yielded a substantial yield of waxes (65%) .…”