Composite catalyst for polyolefin depolymerization

Abstract

A catalyst composition and method of use for the depolymerization of polyolefin waste into useful petrochemical products is described. The composition is a composite of at least one zeolite catalyst and one or more co-catalysts that are solid inorganic materials. These catalyst composites are used in conjunction with heat to increase the depolymerization reaction rate of the feed stream and suppress the poisoning effects of non-polyolefin polymers that may be present. This reduces residence time in the depolymerization unit, resulting in a more efficient process.

Claims

1. A composite catalyst for depolymerizing a polyolefin containing a non-polyolefin component, comprising Zr(HPO4)2 and β-zeolite, Y-zeolite, or ZSM-5.

2. The composite catalyst according to claim 1, wherein the total amount of Zr(HPO4)2 is 20 to 90% by weight of the composite catalyst.

3. A method for depolymerizing a polymer, a) Adding a polyolefin feed stream, Zr(HPO4)2, and a composite catalyst containing β-zeolite, Y-zeolite, or ZSM-5 to a reactor heated to a temperature of 200°C to 600°C, b) A method comprising the step of reacting the polyolefin feed stream with the composite catalyst to depolymerize the polyolefin feed stream.

4. The method according to claim 3, wherein the amount of the composite catalyst present is greater than 0% by weight and up to 20% by weight of the polyolefin-based feed stream.

5. The method according to claim 3, wherein the polyolefin-based supply stream is low-density polyethylene, high-density polyethylene, polypropylene, or a combination thereof.

6. The method according to claim 3, wherein the polyolefin-based feed stream contains at least one non-polyolefin component in an amount of up to 10%.

7. The method according to claim 6, wherein the at least one non-polyolefin component is selected from the group consisting of nylon polymer, cellulose, polyaramid, polyurethane, and polyvinyl polymer.

8. The method according to claim 7, wherein the polyolefin-based supply stream is post-consumer waste or post-industrial waste.

9. The method according to claim 6, wherein the at least one non-polyolefin component is a pigment having at least one nitrogen atom.

10. The method according to claim 3, wherein the polyolefin-based feed stream includes both post-industrial waste and post-consumer waste.

11. A method for depolymerizing a polymer, a) Adding a polyolefin feed stream having up to 10% by weight of non-polyolefin components, and a composite catalyst containing Zr(HPO4)2 and β-zeolite, Y-zeolite, or ZSM-5 to a reactor heated to a temperature of 200°C to 600°C, b) A method comprising the step of reacting the polyolefin feed stream with the composite catalyst to depolymerize the polyolefin feed stream.

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