High efficiency process for separating fillers from catalyst and gases in a fluid bed catalytic pyrolysis process
A process that separates the fillers found in plastics from catalyst and the gases in a fluid bed catalytic pyrolysis process for the conversion of waste plastics, polymers, and other waste materials to useful chemical and fuel products such as paraffins, olefins, and aromatics such as BTX, is described.
1. A method for producing olefins and aromatics comprising:
passing a feed stream comprising plastics, at least one of which contains filler material, to a fluidized bed reactor comprising a catalyst; wherein the filler material has a particle size that is smaller than a particle size of the fluid bed catalyst;
catalytically reacting the feed stream with the catalyst in the fluidized bed reactor to form a product mixture comprising a first mass ratio of catalyst to filler material;
recovering a vapor effluent from the product mixture, wherein the vapor effluent comprises catalyst particles and filler material;
passing the vapor effluent through a solids separation system comprising passing the vapor effluent into a first cyclone and separating a first bottoms fraction and a first overflow fraction;
wherein the first cyclone is a classifier cyclone;
wherein the first bottoms fraction has a second mass ratio that is greater than the first mass ratio;
passing the overflow fraction from the first cyclone into a second cyclone and separating a second bottoms fraction and a second overflow fraction;
wherein the first cyclone has a first separation efficiency for the catalyst particles and the second cyclone has a second separation efficiency for the particles that is greater than the first separation efficiency;
wherein the second bottoms fraction has a third mass ratio that is less than the first mass ratio;
discarding the second bottoms fraction and
recovering olefins, aromatics, or some combination thereof from the second overflow fraction exiting the second cyclone.
2. The method of claim 1 wherein the second cyclone or series of cyclones comprises one or more recovery cyclones or multiclones.
3. The method of claim 1 wherein at least a portion of solids recovered in the first bottoms fraction from the one or more classifier cyclones is returned to the fluidized bed reactor.
4. The method of claim 1 wherein a stream comprising more ethylene, propylene, or both than the feed stream is separated from volatile products.
5. The method of claim 1 wherein the catalyst is a solid catalyst and wherein the step of catalytically reacting is catalytically pyrolyzing and comprises pyrolyzing in the presence of the solid catalyst in the fluidized bed reactor to produce the vapor effluent and used catalyst with coke, and wherein at least 90% of the carbon in the feed is converted to coke and volatile products.
6. The method of claim 1 wherein the feed stream comprises the plastics chosen from among polyethylene, polypropylene, polyesters, polyethylene terephthalate (PET), acrylonitrilebutadiene-styrene (ABS) copolymers, polyethylenefuranoate (PEF), polyamide, polyurethane, polyethers, polycarbonates, poly(oxides), poly(sulfides), polyarylates, polyetherketones, polyetherimides, polysulfones, polyurethanes, polyvinyl alcohols; polymers produced by polymerization of monomers comprising dienes, olefins, styrenes, acrylates, acrylonitrile, methacrylates, methacrylonitrile, diacids and diols, lactones, diacids and diamines, lactams, vinyl esters, block copolymers thereof, and alloys thereof; thermoset polymers comprising epoxy resins phenolic resins, melamine resins, alkyd resins, vinyl ester resins unsaturated polyester resins, crosslinked polyurethanes, and polyisocyanurates; crosslinked elastomers comprising polyisoprene, polybutadiene, styrene-butadiene, styrene-isoprene, and ethylene-propylene-diene monomer polymer; and mixtures thereof.
7. The method of claim 1 wherein the catalyst in the fluidized bed reactor comprises a zeolite.
8. The method of claim 1 wherein a solid co-reactant comprising agricultural lime, calcium oxide, calcium hydroxide, magnesium oxide, magnesium hydroxide, limestone, hydrotalcites, activated carbon, zeolite, other solid basic material, or some combination thereof, is fed to a thermal treatment reactor.
9. The method of claim 1 wherein the vapor effluent from the fluidized bed catalytic reactor comprises at least 10 mass % BTX, or in a range of 10 to 90 mass % BTX.
10. The method of claim 1 wherein the vapor effluent comprises CH4 and C2-C4 paraffins; and wherein 50 to 100 mass % of the CH4 and C2-C4 paraffins is combusted in a regenerator.
11. The method of claim 1 wherein, in one or more of the classifier cyclones, a ratio of vortex diameter to cylinder diameter can be 0.2, or 0.3, or 0.4, or 0.5, or 0.6, or 0.7, or lie within a range from 0.1 to 0.8, or from 0.3 to 0.7, or from 0.4 to 0.6, or from 0.45 to 0.55, or from 0.49 to 0.51, or a ratio of vortex length (S) to cylinder length can be 0.5, or 0.6, or 0.7, or 0.8, or 0.9, or lie within a range from 0.3 to 0.95, or from 0.5 to 0.95, or from 0.8 to 0.95, or from 0.85 to 0.95, or a ratio of underflow diameter to the vortex diameter can be 0.02, or 0.1, or 0.15, or 0.2, or 0.25, or 0.3, or 0.5, or 1.0, or 1.25, or lie within a range from 0.02 to 1.25, or from 0.02 to 0.5, or from 0.1 to 0.3, or from 0.15 to 0.25, or a ratio of inlet height to inlet width can be 0.75, or 1, or 1.5, or 2, or 2.4, or 3, or 4, or 5 or can lie within a range from 0.75 to 5, or from 1.5 to 4, or from 2 to 3, or from 2.2 to 2.6, or a ratio of the vortex length (S) to total height (H) can be 0.1, or 0.2, or 0.3, or 0.36, or 0.4, or 0.5, or 0.6, or 0.8, or lie within a range from 0.1 to 0.8, or from 0.2 to 0.6, or from 0.3 to 0.4, or from 0.34 to 0.38.
12. The method of claim 2 wherein the one or more recovery cyclones comprises at least one multiclone.
13. The method of claim 1 wherein the feed stream is treated in a thermal treatment reactor and condensed phases are passed to the fluidized bed reactor.
14. The method of claim 8 wherein at least a portion of the solid co-reactant material is separated from the product stream of the thermal treatment reactor and transferred to a combustion regenerator, wherein the carbonaceous materials are reacted with air and at least a portion of a hot solid co-reactant material is returned to the thermal treatment reactor.
15. The method of claim 14 wherein a hot flue gas exiting the combustion regenerator is passed to a catalyst heater to heat the catalyst for the fluidized bed reactor.
16. The method of claim 2 wherein filler material is recovered from the solids separation system.
17. The method of claim 16 wherein the filler material that is recovered in the solids separation system stripped of volatile materials by passing a stream of steam, nitrogen, CO, CO 2 , CH 4 , He, or some combination of these, or a recycle stream from the product gases through the filler material, condensing the stream, separating organic and aqueous phases, sending the organic phase to product recovery, sending the aqueous phase to wastewater recovery, and sending the filler material that has been stripped of volatile materials to the filler regenerator, discarding the filler material, or a combination thereof.
18. The method of claim 1 wherein the mass ratio of catalyst particles to filler particles entering the classifier cyclone is at least 1, 2, 5, 10, 20, 30, or 50, or from 0.1 to 50, from 0.5 to 30, or from 5 to 20.