Robotic separation of plastics for chemical recycling
The invention comprises methods of robotically separating unwanted heteroatom-containing materials from a plastic mixture and catalytically pyrolyzing the resulting mixed plastics to obtain olefins and aromatics. Systems and compositions useful in the catalytic pyrolysis of plastics are also described.
1. A method of converting a mixture comprising plastics to olefins, or aromatics, or both, comprising:
a. providing a first mixture comprising the mixture comprising plastics and removing heteroatom containing materials from the feed mixture by use of a robotic mechanical system for removing materials;
b. mechanically and/or thermally processing of the remaining mixture;
c. feeding the mixture to a pyrolysis reactor;
d. pyrolyzing the remaining feed mixture within the reactor in the presence of a catalyst under reaction conditions sufficient to produce a raw product mixture comprising one or more olefins, or one or more aromatics, or both.
2. A method of converting a mixed feed of materials, comprising:
a. providing a first stream comprising one or more polymers;
b. separating heteroatom containing materials from the first stream by robotic mechanical separation to produce a separated second stream and a heteroatom containing stream;
c. feeding the second stream of materials to a fluidized bed pyrolysis reactor comprising a catalyst;
d. pyrolyzing the second stream in the reactor;
e. transferring at least a portion of the used catalyst with coke to a regenerator where the coke is reacted with oxygen or air to form hot regenerated catalyst and returning at least a portion of the hot regenerated catalyst to the fluidized bed reactor wherein heat from the hot regenerated catalyst provides energy to the step of pyrolyzing.
3. A method of catalytically pyrolyzing a feed mixture comprising a mixture of polymers in a fluidized bed reactor wherein at least a portion of the heteroatom containing materials have been robotically mechanically separated from the feed and the amount of oxygen introduced into the process is at least enough such that combustion of feed materials or other components with the introduced oxygen increases the temperature of the reacting mixture by at least 25° C., or at least 100° C., or at least 200° C., or at least 300° C., or from 50° C. to 400° C., or from 100° C. to 400° C., or from 200° C. to 400° C.
4. The method of claim 1 wherein the materials to be removed comprise one or more heteroatoms selected from among oxygen, nitrogen, sulfur, chlorine, bromine, iodine, alkali or alkaline earth metals, and transition metals.
5. The method of claim 1 wherein the robotic mechanical separation comprises:
a. Identifying the objects to be removed from a waste feed mixture;
b. Gripping the objects to be removed with an articulated robotic arm;
c. Removing the objects identified to be removed;
d. Processing the remaining materials in a pyrolysis or catalytic pyrolysis process.
6. The method of claim 5 wherein the robotic mechanical separation comprises:
a. at least one robot arm provided with a gripping member;
b. an artificial visualization system, one or more sensors, or both, allowing the localization of objects, and partial recognition of their nature;
c. a means for processing the information supplied by the vision system or by the one or more sensors, or both, and a means of piloting the robotic arm for the selective removal of the objects comprising heteroatoms.
7. The method of claim 5 wherein the objects to be removed are gripped mechanically by suction, compression, mechanical action, vacuum system, or some combination of these.
8. The method of claim 5 wherein step b) comprises employing at least one sensor to identify the objects to be removed by recognizing their constituent material.
9. The method of claim 8 wherein the one or more sensors detect objects using Fourier Transform Near Infra-Red (FT-NIR) spectroscopy, optical vision systems, or X-ray fluorescence.
10. The method of claim 1 wherein characterization data obtained by the mechanical robotic separation unit are collected, stored, and analyzed using artificial intelligence to enhance the accuracy of the separation process.
11. The method of claim 1 wherein the feed mixture materials are selected from biomass, polyethylene (PE), polypropylene (PP), polyacetylene, polybutylene, polyolefins, polyethylene terephthalate (PET), polybutyleneterephthalate, copolyesters, polyester, polycarbonate, polyurethanes, polyamides, polystyrene (PS), polyacetal, epoxies, polycyanurates, polyacrylics, polyurea, vinyl esters, polyacrylonitrile, polyvinyl alcohol, polyvinylchloride (PVC), polyvinyl acetate, nylon, copolymers such as: ethylene-propylene, EPDM, acrylonitrile-butadienestyrene (ABS), nitrile rubber, natural and synthetic rubber, tires, styrene-butadiene, styrene-acrylonitrile, styrene-isoprene, styrene-maleic anhydride, ethylene-vinylacetate, nylon 6, nylon 66, nylon 12, nylon 46, filled polymers, polymer composites, plastic alloys, other polymeric materials, and polymers or plastics dissolved in a solvent, whether obtained from polymer or plastic manufacturing processes as waste or discarded materials, post-consumer recycled polymer materials, materials separated from waste streams such as municipal solid waste, black liquor, wood waste, or other biologically produced materials, or some combination of these.
12. The method of claim 3 wherein the feed mixture materials comprise PVC, or PVDC, or both PVC and PVDC that are removed from the feedstream.
13. The method of claim 3 wherein the feed mixture materials comprise multi-layer packaging that comprises one or more metallic components and that are removed from the feedstream.
14. The method of claim 3 wherein the mixture of polymers is molten and further comprising filtering solids from the molten mixture prior to pyrolyzing.
15. The method of claim 2 wherein the feed or mixture of polymers comprises at least 80 mass % of polyethylene or polypropylene, or a combination of both.
16. The method of claim 2 wherein the polymer or mixture of polymers comprises at least 80 mass % of PET or other polyesters.
17. The method of any of claims 2 or 3 wherein olefins, or aromatics, or aromatics and olefins are recovered from the product stream.
18. The method of claim 2 wherein at least a portion of the product gases is combusted in the catalyst regeneration unit.
19. The method of any of claims 1-6 wherein the catalytic pyrolysis is conducted in a fluidized bed, circulating bed, bubbling bed, or riser reactor at an operating temperature in the range from 300° C. to 800° C., or from 350° C. to 700° C., or from 400° C. to 650° C., or from 450° C. to 625° C., or from 500° C. to 600° C.
20. The method of claim 2 wherein the step of pyrolyzing comprises a zeolite catalyst.