Method of removing sulfur dioxide from a flue gas stream

• US 7,531,154 B2
• Filed: 08/18/2005
• Issued: 05/12/2009
• Est. Priority Date: 08/18/2005
• Status: Expired due to Fees

• Current Assignee: Solvay Chemicals Incorporated (Solvac SA)
• Original Assignee: Solvay Chemicals Incorporated (Solvac SA)
• Inventors: Maziuk, John Jr.
• Primary Examiner(s): Vanoy; Timothy C
• Application Number:
  US11/208,432
• Publication Number:
  US 20070041885A1
• Time in Patent Office: 1,363 Days
• Field of Search: 423/243.01, 423/243.08, 423/244.01, 423/244.07, 423/244.08
• US Class Current: 423/243.01
• CPC Class Codes: B01D 53/508 by treating the gases with solids

Abstract

A method of removing SO₂ from a flue gas stream including SO₂ includes providing a source of trona and injecting the trona into the flue gas stream. The temperature of the flue gas is between about 600° F. and about 900° F. The trona is maintained in contact with the flue gas for a time sufficient to react a portion of the trona with a portion of the SO₂ to reduce the concentration of the SO₂ in the flue gas stream.

Claims

1. A method of removing SO₂ from a flue gas stream comprising SO₂, comprising:

providing a source of trona, wherein the mean particle size of the trona is less than about 40 micron;

injecting the trona into the flue gas stream, wherein the trona is injected at a rate with respect to the flow rate of the SO₂ to provide a normalized stoichiometric ratio of sodium to sulfur of between about 1.0 and about 1.5, further wherein the temperature of the flue gas is between about 630°

F. and about 900°

F.; and

maintaining the trona in contact with the flue gas for a time sufficient to react a portion of the trona with a portion of the SO₂ to reduce the concentration of the SO₂ in the flue gas stream by at least about 78%.

2. The method of claim 1 wherein the mean particle size of the trona is between about 10 micron and about 40 micron.

3. The method of claim 1 wherein the mean particle size of the trona is between about 24 micron and about 28 micron.

4. The method of claim 1 wherein the temperature of the flue gas is greater than about 700°

F.

5. The method of claim 1 wherein the temperature of the flue gas is less than about 800°

F.

6. The method of claim 1 wherein the temperature of the flue gas is less than about 750°

F.

7. The method of claim 1 wherein the temperature of the flue gas is between about 700°

F. and about 750°

F.

8. The method of claim 1 wherein the trona is injected as a dry material.

9. The method of claim 1 further comprising milling the trona to a desired mean particle size at a location proximate the flue gas stream.

10. The method of claim 1 further comprising collecting a reaction product of the trona and the SO₂ in an electrostatic precipitator.

11. The method of claim 1, wherein the concentration of the SO₂ in the flue gas stream is reduced by at least about 80%.

12. The method of claim 1, wherein the maintaining of the trona in contact with the flue gas to reduce the concentration of the SO₂ in the flue gas substantially avoids formation of solids buildup on process equipment.

13. The method of claim 1, wherein the maintaining of the trona in contact with the flue gas to reduce the concentration of the SO₂ in the flue gas substantially avoids solids buildup in a particulate collection device.

14. A method of removing SO₂ from a flue gas stream comprising SO₂, comprising:

providing a source of trona having a mean particle size between about 10 micron and about 40 micron;

injecting the trona as a dry granular material into the flue gas stream, wherein the trona is injected at a rate with respect to the flow rate of the SO₂ to provide a normalized stoichiometric ratio of sodium to sulfur of between about 1.0 and about 1.5, further wherein the temperature of the flue gas is between about 700°

F. and about 800°

F.; and

maintaining the trona in contact with the flue gas for a time sufficient to react a portion of the trona with a portion of the SO₂ to reduce the concentration of the SO₂ in the flue gas stream by at least about 78%.

15. The method of claim 14 wherein the mean particle size of the trona is between about 24 micron and about 28 micron.

16. The method of claim 14, wherein the temperature of the flue gas is between about 700°

F. and about 750°

F.

17. The method of claim 14 further comprising adjusting the flue gas temperature upstream of the trona to obtain the desired flue gas temperature where the trona is injected.

18. The method of claim 17 wherein the adjusting further comprises introducing ambient air into the flue gas stream and monitoring the flue gas temperature where the trona is injected.

19. The method of claim 17 wherein the adjusting further comprises controlling the flow of a material through a heat exchanger in communication with the flue gas.

20. The method of claim 14, wherein the concentration of the SO₂ in the flue gas stream is reduced by at least about 80%.