Recycling of plastics in a steam cracker

• US 5,731,483 A
• Filed: 11/17/1995
• Issued: 03/24/1998
• Est. Priority Date: 07/20/1993
• Status: Expired due to Fees

• Current Assignee: "DER Gruene Punkt" Duales System Deutschland AG
• Original Assignee: BASF AG (BASF SE)
• Inventors: Stabel, Uwe, Fried, Andreas, Woerz, Helmut, Kotkamp, Ruediger
• Primary Examiner(s): Caldarola, Glenn
• Assistant Examiner(s): Yildirim, Bekir L.
• Application Number:
  US08/553,658
• Time in Patent Office: 858 Days
• Field of Search: 585/241, 585/648, 208/130
• US Class Current: 585/241
• CPC Class Codes: B29B 13/022 Melting the material to be shaped
• CPC Class Codes: B29B 17/02 Separating plastics from other materials
• CPC Class Codes: B29K 2023/06 PE, i.e. polyethylene
• CPC Class Codes: B29K 2023/12 PP, i.e. polypropylene
• CPC Class Codes: B29K 2025/00 Use of polymers of vinyl-aromatic compounds or derivatives thereof as moulding material
• CPC Class Codes: B29K 2027/06 PVC, i.e. polyvinylchloride
• CPC Class Codes: B29K 2105/065 containing impurities
• CPC Class Codes: B29K 2711/12 Paper, e.g. cardboard
• CPC Class Codes: C10G 1/002 in combination with oil conversion- or refining processes
• CPC Class Codes: C10G 1/10 from rubber or rubber waste
• CPC Class Codes: C10G 9/36 with heated gases or vapours
• CPC Class Codes: Y02W 30/62 Plastics recycling; Rubber recycling

Abstract

A process for recycling plastic waste in a steam cracker, wherein a melt obtained from plastic waste is converted into products at from 400° 550° C., and a distillate fraction is separated off from the products at from 180° to 280° C. and is fed as feed material to a steam cracker.

Claims

1. A process for recycling plastic waste in a steam cracker, wherein a melt obtained from heating plastic waste is converted into steam cracker feed products by heating the melt at from 400°

to 550°

C. and a distillate fraction separated from said products at from 180°

to 280°

C. is fed to a steam cracker.

2. A process as defined in claim 1, wherein

the plastic waste is melted,

the melt is fed to a reactor where the polymers are converted into products at from 400°

to 550°

C.,

a distillate fraction is separated by distillation at from 200°

to 280°

C. from the products,

the other products are returned to the reactor, with the exception of residues and solids and any inorganic acids, and

the distillate fraction separated off is introduced, optionally after further separation, as a feed material into the steam cracker.

3. A process as defined in claim 1, wherein the distillate fraction is separated by distillation from the products by a process in which

the products are separated by means of a 1st column which is directly downstream of the reactor, and into

a bottom product resulting at from 300°

to 420°

C., which, after removal of the residues and solids, is returned to the tubular furnace, and into

a top product resulting at from 200°

to 280°

C., which, after partial condensation, is fed to a 2nd column at from 70°

to 150°

C.,

the liquid/gas mixture resulting after the partial condensation is separated by means of the above 2nd column into

a liquid mixture emerging at the bottom of the 2nd column, which is, in part returned to the 1st column, and, in part, used as feed material for the steam cracker, and into

a gas mixture emerging at the top of the 2nd column, which is used as feed material for the steam cracker.

4. A process for recycling chlorine-containing and/or aromatics-containing plastic waste in a steam cracker as defined in claim 1, wherein

the plastic waste is melted at from 280°

to 380°

C. with dehydrohalogenation of the chlorine-containing plastic,

the melt is fed into a reactor where the polymers are converted at from 410°

to 530°

C. into products,

the above products are separated by means of a 1st column which is directly downstream of the reactor into

a bottom product resulting at from 330°

to 450°

C., which, after removal of the residues and solids, is returned to the reactor, and into

a top product resulting at from 200°

to 280°

C., which, after partial condensation, is fed to a 2nd column at from 70°

to 150°

C.,

the liquid/gas mixture resulting after the partial condensation is separated by means of the above 2nd column, into

a liquid mixture emerging at the bottom of the 2nd column, which is, in part, returned to the 1st column and, in part, fed to a distillation or extraction unit suitable for removing aromatics, and into

a gas mixture emerging at the top of the 2nd column, which is used as feed material for the steam cracker.

5. A process as defined in claim 4, wherein the liquid mixture fed to the distillation or extraction unit is separated into

a liquid fraction which is used as feed material for the steam cracker, and into

an aromatic fraction.

6. A process as defined in claim 1, wherein the plastic waste employed comprises a blow molded fraction consisting of bottles and containers composed essentially of polyolefins, optionally with adherent soiling, sticky label materials, fillers and residual contents.

7. A process as defined in claim 1, wherein the plastic waste comprises a mixed plastic fraction composed essentially of polyolefins, polystyrene and polyvinyl chloride, optionally with adherent soiling, sticky label materials, fillers and residual contents.

8. A process as defined in claim 1, wherein the plastic waste employed comprises a sheet fraction composed essentially of polyethylene, polypropylene, including optional soiling, sticky label materials, filler and residual contents.

9. A process as defined in claim 1, wherein the plastic waste employed comprises a light fraction consisting essentially of polyethylene, polypropylene and polystyrene, including optional soiling, sticky label materials, fillers, residual contents.