Plasma oxidation of an exhaust gas stream from chlorinating titanium-containing material

• US 5,824,277 A
• Filed: 12/05/1996
• Issued: 10/20/1998
• Est. Priority Date: 12/06/1995
• Status: Expired due to Fees

• Current Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Campos, Daniel, Lyke, Stephen Erwin
• Primary Examiner(s): Straub, Gary P.
• Assistant Examiner(s): Vanoy, Timothy C.
• Application Number:
  US08/761,734
• Time in Patent Office: 684 Days
• Field of Search: 204/157.3, 204/157.4, 204/164, 204/174, 423/242.1, 423/418.2, 423/437 R, 423/532, 423/539, 423/DIG. 10
• US Class Current: 423/242.1
• CPC Class Codes: B01D 2259/818 Employing electrical discharges or the generation of a plasma
• CPC Class Codes: B01D 53/007 by irradiation
• CPC Class Codes: B01D 53/32 by electrical effects other than those provided for in group B01D61/00
• CPC Class Codes: B01D 53/485 containing only one sulfur compound other than sulfur oxides or hydrogen sulfide
• CPC Class Codes: B01D 53/8606 only one sulfur compound other than sulfur oxides or hydrogen sulfide
• CPC Class Codes: B01J 19/081 employing particle radiation or gamma-radiation
• CPC Class Codes: B01J 19/088 giving rise to electric discharges for heating purposes H05B7/00; for the production of ozone C01B13/11, H01T19/00
• CPC Class Codes: B01J 19/122 Incoherent waves gamma-radiation B01J19/082
• CPC Class Codes: B01J 2219/0849 Corona pulse discharge
• CPC Class Codes: B01J 2219/0894 Processes carried out in the presence of a plasma
• CPC Class Codes: Y10S 423/10 Plasma energized

Abstract

A process is disclosed for treating an exhaust gas stream containing COS and CO arising from chlorinating titanium-containing material with a cold plasma wherein oxygen is present and selectively oxidizing COS.

Claims

1. A process for treating an exhaust gas stream comprising COS, wherein the exhaust gas stream is produced from the chlorination of titanium-containing material, comprising the steps of:

(a) passing the exhaust gas stream into a cold plasma generating zone generating a cold plasma at a temperature within the range of about -20°

C. to about 500°

C. in the presence of oxygen, and

(b) oxidizing COS to SO_x, wherein x is 2 or 3.

2. The process of claim 1, wherein the exhaust gas stream comprises COS and CO, and COS is selectively oxidized to SO_x and CO_z, wherein x is 2 or 3 and z is 1 or 2.

3. The process of claim 1 or claim 2, wherein the temperature of the cold plasma is within the range of about 0°

C. to about 300°

C.

4. The process of claim 3, wherein the temperature of the cold plasma is within the range of about 0°

C. to about 150°

C.

5. The process of claim 1, claim 2 or claim 4, wherein the plasma is generated by ionizing radiation selected from the group consisting of alpha-rays, beta-rays, gamma-rays, ultraviolet light, x-rays and high energy electron beam.

6. The process of claim 1, claim 2 or claim 4, wherein the plasma is generated by electrical discharge selected from the group consisting of radio frequency, microwave, laser induced discharge, dc or ac glow discharge, dc or ac corona, arc discharge, silent discharge and streamer corona.

7. The process of claim 1 or claim 2, wherein step (b) occurs in the absence of an oxidation catalyst.

8. The process of claim 1 or claim 2, wherein step (b) occurs in the presence of an oxidation catalyst.