Complexation and removal of mercury from flue gas desulfurization systems

Patent metadata

Field	Value
Publication number	US-10124290-B2
Application number	US-201615241259-A
Country	US
Kind code	B2
Filing date	Aug 19, 2016
Priority date	Aug 21, 2015
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

A method for the reduction and prevention of mercury emissions into the environment from combusted fossil fuels or other off-gases with the use of peracetic acid is disclosed. The peracetic acid is used for the capture of mercury from the resulting flue gases using a flue gas desulfurization system or scrubber. The method uses peracetic acid in conjunction with a scrubber to capture mercury and lower its emission and/or re-emission with stack gases. The method allows the use of coal as a cleaner and environmentally friendlier fuel source as well as capturing mercury from other processing systems.

First claim

What is claimed is:

1. A method for reducing mercury emissions, comprising: providing a gas stream comprising mercury; and
passing the gas stream into a scrubber comprising a scrubber liquor and peracetic acid,
wherein the scrubber liquor is a limestone slurry and the limestone slurry and the peracetic acid are mixed.

2. The method of claim 1 , further comprising mixing acetic acid and an oxidant to form the peracetic acid.

3. The method of claim 2 , wherein the oxidant is selected from hydrogen peroxide, sodium hypochlorite and mixtures of the same.

4. The method of claim 3 , wherein the oxidant is hydrogen peroxide.

5. The method of claim 4 , wherein the mercury is from combusted coal.

6. The method of claim 4 , wherein the scrubber is a wet scrubber selected from a spray tower system, a jet bubbler system, and a co-current packed tower system.

7. The method of claim 4 , wherein the peracetic acid is added to the scrubber liquor and then the scrubber liquor is added to the scrubber.

8. The method of claim 4 , wherein the peracetic acid is added to the scrubber containing the liquor.

9. The method of claim 4 , wherein the peracetic acid is added to a virgin liquor then the virgin liquor is added to the scrubber.

10. The method of claim 4 , wherein the peracetic acid is added to a make-up liquor then the make-up liquor is added to the scrubber.

11. The method of claim 4 , wherein the peracetic acid is added to a return liquor then the return liquor is added to the scrubber.

12. The method of claim 4 , wherein the peracetic acid is added to a reclaimed liquor then the reclaimed liquor added to the scrubber.

13. The method of claim 4 , wherein the peracetic acid is added to a liquor and then the peracetic acid and liquor are injected directly into flue gases then the flue gases are added to the scrubber.

14. The method of claim 4 , wherein the peracetic acid is added to a recirculation loop of the scrubber liquor.

15. The method of claim 4 , wherein the peracetic acid is added to a low solids return stream to the scrubber from a scrubber purge stream.

16. The method of claim 4 , wherein the peracetic acid is added to an aqueous stream introduced into the scrubber, wherein the aqueous stream is from a demister or a make-up water stream.

17. The method of claim 4 , wherein the mercury is from an incinerator, cement kiln, or an ore refinery.

18. The method of claim 4 , further comprising adding sulfur dioxide to the gas stream.

Assignees

• Ecolab Usa Inc

Inventors

• Denny Nicholas R
• Keiser Bruce A
• Dotzauer David M
• Carlson Wayne M

Classifications

• B01D53/78

  with gas-liquid contact · CPC title

• B01D2251/70

  Organic acids · CPC title

• B01D53/502

  characterised by a specific solution or suspension · CPC title

• B01D2251/108

  Halogens or halogen compounds · CPC title

• B01D2251/404

  of calcium · CPC title