Process and system for depolymerizing plastic

A process for continuously depolymerizing plastic, the process comprising:

• (a) mixing solid polyethylene terephthalate (PET) particles with a solvent and a catalyst to produce a heterogeneous reaction mixture;
• (b) transmitting the heterogeneous reaction mixture through a first section of a first heat exchanger to preheat the heterogeneous reaction mixture, wherein the heterogeneous reaction mixture is passed through the first portion of the first heat exchanger at a pump flow rate by a pump, wherein the pump maintains a continuous flow rate that ensures a particle speed of the heterogeneous mixture great enough to keep the particles in suspension such that particles do not settle in the lines and clog the system;
• (c) transmitting the preheated heterogeneous reaction mixture into a heating region of a heating chamber;
• (d) heating the heterogeneous reaction mixture within the heating region of the heating chamber with a heat source which indirectly heats the heterogeneous mixture using a heat transfer fluid to a reaction temperature of at least 230° C. to initiate conversion of the heterogeneous reaction mixture into a homogeneous reaction solution comprising a liquefied reaction product, and maintaining the mixture at the reaction temperature in a hold tube for at least one minute to complete the conversion of the heterogeneous reaction mixture to the homogeneous reaction solution;
• (e) transmitting the homogeneous reaction solution through a second section of the first heat exchanger to cool the homogeneous reaction solution;
• (f) transmitting the homogeneous reaction solution to a settling tank to allow the liquefied reaction product to convert into a solid reaction product and precipitate from the cooled homogeneous reaction solution.