(a) a pump for transmitting a heterogeneous reaction mixture comprising solid plastic particles and a solvent at a particle speed sufficient to maintain the plastic particles in suspension in the solvent;

(b) a first heat exchanger fluidly coupled to the pump, wherein the first head exchanger is positioned downstream of the pump and comprises a cooling section and a heating section, wherein the heating section of the first heat exchanger is adapted to preheat the heterogeneous reaction mixture;

(c) a heating apparatus comprising a heating chamber, the heating chamber including a material passageway having an inlet fluidly coupled to an outlet of the heating section of the first heat exchanger, wherein the material passageway defines a heating region adapted to heat the heterogeneous reaction mixture to at least a reaction temperature sufficient to initiate conversion of the heterogeneous reaction mixture into a homogeneous reaction solution comprising a liquefied reaction product;

(d) a hold tube adapted to maintain the heterogeneous reaction mixture at or above the reaction temperature in order to complete the conversion of the heterogeneous reaction mixture into a homogeneous reaction solution, the hold tube having a tube inlet and a tube outlet, wherein the tube inlet is fluidly coupled to an outlet of the material passageway of the heating chamber, and wherein tube outlet is fluidly coupled to an inlet of the cooling section of the first heat exchanger.