Methods and systems for conversion of mixed plastics to high value chemicals

A method of processing a mixed plastic waste feed to produce a high value chemical (HVC) product, the method comprising:

• introducing a mixed plastic waste feed containing a plurality of plastic polymers to a depolymerization unit;
• operating the depolymerization unit at a temperature and a residence time sufficient to at least partially depolymerize the plurality of plastic polymers in the mixed plastic waste feed to produce a hydrogen-rich molten oligomers product stream containing inorganic products and a gas stream containing volatile hydrocarbons and heteroatoms;
• supplying the hydrogen-rich molten oligomers product stream and a hydrogen stream to a first cracking unit containing a cracking catalyst to produce a first hydrocarbonaceous stream and a first slurry stream, the first cracking unit being a continuous cracking unit and the first slurry stream containing a portion of the cracking catalyst, the inorganic products, and residual hydrocarbons;
• passing the first slurry stream from the first cracking unit to a first separation unit to produce a second slurry stream containing the inorganic products and the residual hydrocarbons and a catalyst-rich stream containing the portion of the cracking catalyst;
• supplying the catalyst-rich stream to the first cracking unit;
• introducing the second slurry stream to a second separation unit to produce a second hydrocarbonaceous stream containing the residual hydrocarbons and an inorganic products-rich stream;
• delivering the first hydrocarbonaceous stream and the second hydrocarbonaceous stream to a distillation unit to produce a distillate stream and a bottoms stream containing residual hydrocarbons, metals, and residual inorganic products;
• processing the bottoms stream in a third separation unit to remove the metals and the residual inorganic products and to produce a recovered hydrocarbon stream;
• mixing the recovered hydrocarbon stream and the distillate stream to produce a hydrogen-rich liquid hydrocarbon stream;
• and
• supplying the hydrogen-rich liquid hydrocarbon stream and a hydrogen-lean hydrocarbon stream to a second cracking unit operated at a temperature ranging from about 400° C. to about 750° C. to produce a HVC product, the hydrogen-lean hydrocarbon stream being one or more of an atmospheric residue, a vacuum residue, a straight run vacuum gas oil, or a cracked vacuum gas oil.

A method of processing a mixed plastic waste feed to produce a high value chemical (HVC) product, the method comprising:

• introducing a mixed plastic waste feed containing a plurality of plastic polymers to a depolymerization unit;
• operating the depolymerization unit at a temperature and a residence time sufficient to at least partially depolymerize the plurality of plastic polymers in the mixed plastic waste feed to produce a hydrogen-rich molten oligomers product stream containing inorganic products from the mixed plastic waste feed and a gas stream containing volatile hydrocarbons and heteroatoms;
• supplying the hydrogen-rich molten oligomers product stream and a hydrogen stream to a thermal hydrotreating unit to produce a first hydrocarbonaceous stream and a slurry stream containing the inorganic products and residual hydrocarbons;
• passing the first slurry stream from the thermal hydrotreating unit to a first separation unit to produce an inorganic products-rich stream and a second hydrocarbonaceous stream containing the residual hydrocarbons;
• delivering the first hydrocarbonaceous stream and the second hydrocarbonaceous stream to a distillation unit to produce a distillate stream and a bottoms stream containing the residual hydrocarbons, metals, and residual inorganic products;
• processing the bottoms stream in a second separation unit to remove the metals and the residual inorganic products and to produce a recovered hydrocarbon stream;
• mixing the recovered hydrocarbon stream and the distillate stream to produce a hydrogen-rich liquid hydrocarbon stream;
• and
• supplying the hydrogen-rich liquid hydrocarbon stream and a hydrogen-lean hydrocarbon stream to a fluid catalytic cracking unit operated at a temperature ranging from about 400° C. to about 750° C. to produce a HVC product, the hydrogen-lean hydrocarbon stream being one or more of an atmospheric residue, a vacuum residue, a straight run vacuum gas oil, or a cracked vacuum gas oil.