High organic concurrent decoating kiln

Patent metadata

Field	Value
Publication number	US-2017051914-A1
Application number	US-201515307708-A
Country	US
Kind code	A1
Filing date	May 22, 2015
Priority date	May 22, 2014
Publication date	Feb 23, 2017
Grant date	—

Abstract

A high organic concurrent decoating kiln includes a low-oxygen zone and a high-oxygen zone. The disclosed kiln allows a gas low in free oxygen to be used in the initial stages of decoating, while a gas higher in free oxygen can be used in the final stages. The total amount of free oxygen used throughout the kiln, in particular at the upstream portion of the kiln, is kept low. Exhaust gas can be recirculated for use in a burner-fired chamber that provides the initial low-oxygen gas to the kiln.

First claim

What is claimed is:

1 . A decoating kiln, comprising:
a rotating drum comprising:
an entry side for accepting metal scrap and a low-oxygen hot gas; and
an exit side for outputting decoated scrap and accepting a high-oxygen hot gas;
an exhaust tube positioned within the rotating drum for exhausting a mixture of exhaust gas and entrained scrap; a cyclone coupled to the exhaust tube for separating the entrained scrap from the exhaust gas; and an exit port coupled to the cyclone for exhausting the exhaust gas.

2 . The decoating kiln of claim 1 , further comprising:
a multicyclone coupled to the exit port for separating particles from the exhaust gas; and a burner-fired chamber coupled to the multicyclone for accepting the exhaust gas and generating the low-oxygen hot gas.

3 . The decoating kiln of claim 1 , further comprising:
a low-oxygen hot gas entry duct coupled to the decoating kiln proximate the entry side; and a high-oxygen hot gas entry duct coupled to the decoating kiln proximate the exit side.

4 . The decoating kiln of claim 2 , further comprising:
a low-oxygen hot gas entry duct coupled to the decoating kiln proximate the entry side; and a high-oxygen hot gas entry duct coupled to the decoating kiln proximate the exit side.

5 . The decoating kiln of claim 4 , wherein:
the exhaust tube is configured to remove exhaust gas from the decoating kiln; and the burner-fired chamber uses at least a portion of the exhaust gas to generate a low-oxygen hot gas provided to the low-oxygen hot gas entry duct.

6 . The system of claim 1 , wherein:
the low-oxygen hot gas is less than approximately 10 percent oxygen; and wherein the high-oxygen hot gas is between approximately 5 percent oxygen and 25 percent oxygen.

7 . A system, comprising:
the decoating kiln of claim 1 comprising a low-oxygen zone proximate the entry side and a high-oxygen zone proximate the exit side.

8 . The system of claim 7 , further comprising:
a low-oxygen hot gas entry duct coupled to the decoating kiln proximate the entry side; and a high-oxygen hot gas entry duct coupled to the decoating kiln proximate the exit side.

9 . The system of claim 8 , further comprising:
the exhaust tube coupled to the decoating kiln for removing exhaust gas from the decoating kiln; and a burner-fired chamber coupled to the exhaust tube and the low-oxygen hot gas entry duct, wherein the burner-fired chamber uses at least a portion of the exhaust gas to generate a low-oxygen hot gas provided to the low-oxygen hot gas entry duct.

10 . The system of claim 7 , further comprising an exhaust tube coupled to the decoating kiln for removing exhaust gas from the decoating kiln, wherein the exhaust gas contains a sufficiently low percentage of free oxygen to be incombustible.

11 . The system of claim 7 , wherein:
the low-oxygen hot gas is less than approximately 10 percent oxygen; and wherein the high-oxygen hot gas is between approximately 5 percent oxygen and 25 percent oxygen.

12 . A method of using the decoating kiln of claim 1 , comprising:
passing coated scrap through a low-oxygen zone of the decoating kiln; and passing coated scrap through a high-oxygen zone of the decoating kiln.

13 . The method of claim 12 , further comprising:
removing exhaust gas and entrained scrap from the decoating kiln; separating the entrained scrap from the exhaust gas.

14 . The method of claim 12 , further comprising:
providing the exhaust gas to a burner-fired chamber; providing air to the burner-fired chamber; burning the exhaust gas and the air to generate a low-oxygen hot gas; providing the low-oxygen hot gas to the decoating kiln proximate the low-oxygen zone.

15 . The method of claim 12 , further comprising:
providing low-oxygen hot gas that is less than approximately 10 percent oxygen along the low-oxygen zone; and providing high-oxygen hot gas that is between approximately 5 percent oxygen and 25 percent oxygen along the high-oxygen zone.

Assignees

• Novelis Inc

Inventors

• Rauch Edwin L

Classifications

• F27B7/36 Primary

  Arrangements of air or gas supply devices · CPC title

• F27D17/00

  Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases · CPC title

• F23G5/20

  having rotating or oscillating drums · CPC title

• F27D7/02

  Supplying steam, vapour, gases or liquids · CPC title

• F23G5/027 Primary

  pyrolising or gasifying stage (pyrolisation of sludge C02F11/00; destructive distillation of carbonaceous materials C10B53/00) · CPC title