Depolymerization of recovered plastic materials

Abstract

Described herein are systems and methods for the depolymerization of polyethylene-based plastics. In one embodiment, a method is disclosed that comprises combining a polyethylene-based plastic with a solvent in a reactor to generate a plastic solvent mixture, heating the plastic solvent mixture in the reactor, and fractionating the plastic solvent mixture into a gas phase product, a solid phase product, and a liquid phase product. In another embodiment, a system is disclosed that comprises a solvent, and a reactor configured to receive the polyethylene-based plastic and the solvent and convert the polyethylene-based plastic into a gas phase product, a solid phase product, and a liquid phase product, the reactor being configured to operate at a temperature greater than 275° C. and at a pressure greater than 2 megapascals.

1 - 12 . (canceled) 
     
     
         13 . A system for depolymerizing a polyethylene-based plastic, the system comprising:
 a solvent; and   a reactor configured to receive the polyethylene-based plastic and the solvent and convert the polyethylene-based plastic into a gas phase product, a solid phase product, and a liquid phase product;   wherein the reactor is configured to operate at a temperature greater than 275° C. and at a pressure greater than 2 megapascals.   
     
     
         14 . The system according to  claim 13 , further comprising a catalyst comprising HCl, H2SO4, 1-butyl-3-methylimidazolium bis[(perfluoroethyl)sulfonyl]-imide ([BMIM][PF 2 ]), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF 6 ]), or combinations thereof. 
     
     
         15 . The system according to  claim 13 , wherein the system is configured to convert at least about 60% of the polyethylene-based plastic into the gas phase product and the liquid phase product. 
     
     
         16 . The system according to  claim 15 , wherein the system is configured to produce a yield of liquid phase product of at least about 30%. 
     
     
         17 . The system according to  claim 13 , wherein the liquid phase product has an oxygen/carbon ratio of about 0.01 to about 0.70. 
     
     
         18 . The system according to  claim 13 , wherein the liquid phase product has a hydrogen/carbon ratio of about 1.4 to about 2.0. 
     
     
         19 . The system according to  claim 13 , wherein the liquid phase product has a high heat value of about 35 MJ/kg to about 45 MJ/kg. 
     
     
         20 . (canceled)