Waste plastic density separation
AssigneeEastman Chemical Company
InventorsBruce Roger DeBruin, Kyle Lyn Collings, James Stewart Nelson
Life of this patent
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Abstract
Methods and systems for separating mixed plastic waste are provided herein. The methods generally comprise separating the mixed plastic waste into a PET-enriched stream and one or more PET-depleted streams. The separating may be accomplished using the combinations of two or more density separation stages. Exemplary density separation stages include sink-float separators and centrifugal force separators. The PET-enriched and PET-depleted streams may be recovered and/or directed to downstream chemical recycling processes.
Claims18
A waste plastic separation method comprising separating a mixed plastic waste (MPW) into a polyethylene terephthalate (PET)-enriched stream and a PET-depleted stream, wherein said PET-enriched stream comprises at least 70 weight percent PET on a dry basis and at least 0.1 weight percent and not more than 10 weight percent halogens on a dry basis, wherein the PET-enriched stream has a microorganism content of less than 105 CFU/g.
A waste plastic separation method comprising:
- (a) introducing mixed waste plastic (MPW) particulates into a first density separation stage;
- and
- (b) feeding an output stream from said first density separation stage into a second density separation stage,
- wherein one of said first and second density separation stages is a low-density separation stage and the other of said first and second density separation stages is a high-density separation stage,
- wherein said low-density separation stage has a target separation density that is less than 1.35 g/cc and at least 1.25 g/cc,
- wherein said high-density separation stage has a target separation density that is at least 0.01 g/cc greater than the target separation density of said low-density separation stage and that is at least 1.31 g/cc.
A waste plastic separation method comprising:
- (a) feeding a stream of a caustic solution into at least one of a first or second density separation stages;
- (b) introducing mixed waste plastic (MPW) particulates into said first density separation stage;
- and
- (c) feeding an output stream from said first density separation stage into the second density separation stage,
- wherein one of said first and second density separation stages is a low-density separation stage and the other of said first and second density separation stages is a high-density separation stage,
- wherein no separate caustic component is introduced into said first density separation stage and/or said second density separation stage as a unit operation separate from said stream of caustic solution in step (a), and wherein said MPW particulates are not subjected to a separate antimicrobial processing stage, comprising addition of a caustic component, before being introduced into said first density separation stage.
Dependencies are inferred from the claim text.