Depolymerization of Plastic Materials

• US 20150210611A1
• Filed: 12/30/2014
• Published: 07/30/2015
• Est. Priority Date: 11/02/2010
• Status: Active Grant

• Current Assignee: Fina Technology, Inc. (Totalenergies Se)
• Original Assignee: Fina Technology, Inc. (Totalenergies Se)
• Inventors: Tippet, Jon, Butler, James, Assef, James, Ashbaugh, John, Clark, Jason, Duc, Michel, Cary, Jean-Bernard
• Granted Patent: US 9,650,313 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B01J 8/062 being installed in a furnace
• CPC Class Codes: C07C 15/46 Styrene; Ring-alkylated styrenes
• CPC Class Codes: C07C 2523/04 Alkali metals
• CPC Class Codes: C07C 4/22 by depolymerisation to the original monomer, e.g. dicyclopentadiene to cyclopentadiene
• CPC Class Codes: C08J 11/18 by treatment with organic material
• CPC Class Codes: C08J 2325/06 Polystyrene
• CPC Class Codes: Y02W 30/62 Plastics recycling; Rubber recycling

Abstract

A styrene monomer reclamation process and system is described. The styrene monomer reclamation process includes providing a waste plastic. The waste plastic includes styrenic polymers. The waste plastic is formed into polymer particles. At least a portion of the polymer particles are dissolved in a solvent to form a polymer stream. The dissolved polymer particles are depolymerized to form a styrene monomer stream.

Claims

1-27. -27. (canceled)

28. A process for reclaiming styrene monomer from a waste plastic comprising:

caustic treating a polymer stream, hydrotreating the polymer stream, or combinations thereof, wherein the polymer stream comprises polymers dissolved from the waste plastic; and

depolymerizing the polymers dissolved from the waste plastic to form styrene monomer.

29. The process of claim 28, wherein the polymer stream is caustic treated before depolymerizing.

30. The process of claim 29, wherein the caustic treatment removes nitrile groups in acrylonitrile polymers in the polymer stream, and converts at least some of the nitrile groups to carboxylate groups.

31. The process of claim 29, wherein the caustic treating of the polymer stream comprises contacting the polymer stream with a caustic solution.

32. The process of claim 28, wherein the polymer stream is caustic treated and then hydrotreated before the depolymerizing.

33. The process of claim 28, wherein the polymer stream is hydrotreated before the depolymerizing.

34. The process of claim 33, wherein the hydrotreating removes halogens from the polymer stream.

35. A process for reclaiming styrene monomer from a waste plastic comprising:

heating a polymer stream to a temperature below a critical temperature of a solvent in the polymer stream, wherein the polymer stream comprises polymers from the waste plastic dissolved in the solvent; and

depolymerizing the polymers dissolved from the waste plastic to form styrene monomer.

36. A process for reclaiming styrene monomer from a waste plastic comprising:

dissolving polymers from the waste plastic to form a plastic stream;

depolymerizing the polymers dissolved from the waste plastic to form a styrene monomer stream; and

cooling the styrene monomer stream by heating the polymer stream in a preheater.

37. The process of claim 36, further comprising after the cooling of the styrene monomer stream, neutralizing the styrene monomer stream to a pH of 5 to 9.

38. The process of claim 37, wherein the neutralizing of the styrene monomer stream comprises combining a neutralizing stream with the styrene monomer stream.

39. The process of claim 38, wherein the neutralizing stream comprises a caustic or amine solution.

40. The process of claim 37, wherein after neutralizing the styrene monomer stream, the styrene monomer stream is fed to a compartment decanter, wherein hydrocarbons are separated from steam condensate and salts from neutralization.

41. A process for reclaiming styrene monomer from a waste plastic comprising:

depolymerizing polymers dissolved from the waste plastic to form styrene monomer in a reactor at a temperature of equal to or greater than 600°

C.

42. The process of claim 41, wherein a residence time of the polymers dissolved from the waste plastic in the reactor is less than or equal to 1 minute.

43. The process of claim 41, wherein the reactor is an adiabatic fixed bed reactor, a fluidized bed reactor, a falling bed reactor, a tubular reactor, or a direct-fired tubular reactor reactor.

44. The process of claim 41, wherein prior to the depolymerizing, the polymers dissolved from the waste plastic are heated to the depolymerization temperature.

45. The process of claim 44, wherein the polymers dissolved from the waste plastic are heated to the depolymerization temperature in less than 3 seconds.