Systems and methods for processing mixed solid waste

• US 9,700,896 B1
• Filed: 02/16/2014
• Issued: 07/11/2017
• Est. Priority Date: 02/16/2013
• Status: Active Grant

• Current Assignee: Upland Road IP Holdco LLC
• Original Assignee: Organic Energy Corporation
• Inventors: Gitschel, George K.
• Primary Examiner(s): Francis, Faye
• Application Number:
  US14/181,718
• Time in Patent Office: 1,241 Days
• Field of Search: 241 19, 241 20
• CPC Class Codes: B02C 18/0084 specially adapted for disintegrating garbage, waste or sewage
• CPC Class Codes: B02C 18/142 with two or more inter-engaging rotatable cutter assemblies
• CPC Class Codes: B02C 18/145 with knives spaced axially and circumferentially on the periphery of a cylindrical rotor unit
• CPC Class Codes: B02C 23/14 with more than one separator
• CPC Class Codes: B03B 9/06 specially adapted for refuse
• CPC Class Codes: B07B 15/00 Combinations of apparatus for separating solids from solids by dry methods applicable to bulk material, e.g. loose articles fit to be handled like bulk material using wet methods B03B7/00; using gas currents B07B9/00
• CPC Class Codes: C10L 2250/06 Particle, bubble or droplet size
• CPC Class Codes: C10L 2290/26 Composting, fermenting or anaerobic digestion fuel components or materials from which fuels are prepared
• CPC Class Codes: C10L 2290/28 Cutting, disintegrating, shredding or grinding
• CPC Class Codes: C10L 2290/54 Specific separation steps for separating fractions, components or impurities during preparation or upgrading of a fuel
• CPC Class Codes: C10L 3/00 Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
• CPC Class Codes: C10L 5/40 essentially based on materials of non-mineral origin
• CPC Class Codes: C10L 5/403 on paper and paper waste
• CPC Class Codes: C10L 5/406 on plastic
• CPC Class Codes: C10L 5/42 on animal substances or products obtained therefrom , e.g. manure
• CPC Class Codes: C10L 5/442 Wood or forestry waste
• CPC Class Codes: C10L 5/445 Agricultural waste, e.g. corn crops, grass clippings, nut shells or oil pressing residues
• CPC Class Codes: C10L 5/46 on sewage, house, or town refuse C10L5/403, C10L5/406 take precedence
• CPC Class Codes: C10L 5/48 on industrial residues and waste materials C10L5/403, C10L5/406 take precedence
• CPC Class Codes: Y02E 50/30 Fuel from waste, e.g. synthetic alcohol or diesel
• CPC Class Codes: Y02W 30/52 : Mechanical processing of waste for the recovery of materials, e.g. crushing, shredding, separation or disassembly

Abstract

Described are methods for processing mixed solid waste. The method includes providing a mixed solid waste stream including dry organic material comingled with wet organic and/or inorganic material. The mixed waste is shredded and then separated using size separation and density separation. The shredder has a cut size and rotation speed that produces less than 20% by mass of particles smaller than 2 inches from the mixed solid waste. The shredded mix solid waste is then separated by density and a portion of the stream is recovered as a recyclable or converted to a high value product.

Claims

1. A method for processing mixed solid waste, comprising:

providing a mixed solid waste stream including dry organic material comingled with wet organic and/or inorganic material;

shredding the solid mixed waste using a shredder with a cut size and rotation speed that produces less than 20% by mass of particles smaller than 2 inches;

separating the shredded material by size to produce an over fraction and an under fraction;

separating the over fraction in a density separator to produce a heavy stream and a light stream; and

converting the light stream or the heavy stream or a downstream portion thereof to a fuel and/or recovering one or more recyclable products therefrom.

2. The method of claim 1, wherein the shredder has a plurality of cutters positioned on a rotor, wherein the cutters engage a cutting surface upon rotation of the rotor.

3. The method of claim 2, wherein the rotor is spun at a speed less than 500 rpm.

4. The method of claim 2, wherein the cutting surface is formed in cutouts in a fixed cutting bar that serves as a counter knife.

5. The method of claim 3, wherein the cutouts have a longitudinal diameter of at least 8 inches.

6. The method of claim 1, wherein the rotor has a diameter of at least 15 inches.

7. The method of claim 1, wherein the shredder is a dual shaft shredder having counter rotating rotors.

8. The method of claim 1, wherein less than 1 wt % of the mixed waste stream is separated as a recovered product using manual labor.

9. The method of claim 1, wherein the mixed waste stream includes at least 15% dry organic waste and at least 30% wet organic waste.

10. The method of claim 1, wherein at least 10 wt % of the mixed waste stream is dry organic waste selected from the group consisting of 3-D plastic, film plastic, paper, cardboard, rubber, textiles, and wood.

11. The method of claim 10, wherein at least 10 wt % of the mixed waste stream is a wet organic waste selected from the group consisting of food waste, animal waste, yard waste and green waste.

12. The method of claim 1, wherein the shredder has a throughput of at least 2 metric tons per hour per single line of mixed solid waste.

13. The method of claim 1, wherein the screening and density separation produce a first stream enriched in wet organics and a second stream enriched in dry organics.

14. The method of claim 1, wherein the wet organics are converted to a fuel or product using a first conversion technique selected from wet digestion, dry digestion, anaerobic digestion, aerobic digestion, or composting.

15. The method of claim 14, wherein the first conversion technique produces biogas.

16. The method of claim 15, wherein the biogas is converted to a liquid fuel or electricity.

17. The method of claim 13, wherein the separation of the wet organic from the dry organic materials yields a dry organic material having less than 25% moisture content and the dry organic material is converted to a refuse derived fuel.

18. The method of claim 13, wherein the dry organic waste is enriched in plastics, the second conversion technique comprising sorting the dry organic material by separating 3-dimensional plastics from 2-dimensional plastics to yield a 3-dimensional recyclable plastic product.

19. The method of claim 1, wherein the mixed waste stream includes at least 20% by weight of low value material selected from the group consisting of wet organics, green waste, food waste, grit, fines less than 1 inch, asphalt, concrete, textiles, wood, rubber, film plastic, PVC, foil, rock, used consumer products, low value glass, composite materials, and combinations of these.

20. The method of claim 1, wherein the mixed waste stream includes inorganic waste, the method further comprising:

separating at least a portion of the inorganic waste from the wet organic waste material and the dry organic waste material to increase purity of the wet organic and dry organic waste streams; and

recovering at least a portion of the dry organic material as a recyclable product.