Method for controlling aerosol production during absorption in ammonia desulfurization

• US 10,369,517 B2
• Filed: 12/26/2018
• Issued: 08/06/2019
• Est. Priority Date: 09/07/2017
• Status: Active Grant

• Current Assignee: Jiangnan Environmental Protection Group Inc.
• Original Assignee: Jiangnan Environmental Protection Group Inc.
• Inventors: Luo, Jing, Qi, Lifang, Wang, Jinyong
• Primary Examiner(s): Vanoy, Timothy C
• Application Number:
  US16/232,320
• Publication Number:
  US 20190126197A1
• Time in Patent Office: 223 Days
• CPC Class Codes: B01D 2251/206 Ammonium compounds
• CPC Class Codes: B01D 2251/608 Sulfates
• CPC Class Codes: B01D 2252/102 Ammonia
• CPC Class Codes: B01D 2257/302 Sulfur oxides
• CPC Class Codes: B01D 2258/0283 Flue gases
• CPC Class Codes: B01D 53/501 by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound
• CPC Class Codes: B01D 53/502 characterised by a specific solution or suspension
• CPC Class Codes: B01D 53/504 characterised by a specific device
• CPC Class Codes: B01D 53/505 in a spray drying process
• CPC Class Codes: B01D 53/75 Multi-step processes
• CPC Class Codes: B01D 53/78 with gas-liquid contact
• CPC Class Codes: B01D 53/96 Regeneration, reactivation or recycling of reactants
• CPC Class Codes: F23J 15/04 using washing fluids scrubbers for removing solids only F23J15/022
• CPC Class Codes: F23J 2215/20 Sulfur; Compounds thereof
• CPC Class Codes: F23J 2217/50 by cleaning fluids (washers or scrubbers)

Abstract

Apparatus and methods for controlling aerosol production during absorption in ammonia desulfurization, by removing sulfur dioxide in flue gas with an absorption circulation liquid containing ammonium sulfite, so as to control the aerosol production during absorption in ammonia desulfurization. Efficient desulfurization and dust removal may be achieved by staged solution composition control and reaction condition control. At the same time ammonia escape and aerosol production during absorption may be controlled. The flue gas may be subjected to preliminary temperature lowering and purification, and may be allowed to contact with an absorption circulation liquid and a fine particle washing circulation liquid sequentially. Levels of solution compositions and reaction temperatures may be controlled.

Claims

1. A method for controlling aerosol production during absorption of sulfur dioxide from a flue gas, the method comprising applying an ammonium salt gradient to the flue gas;

wherein the applying an ammonium salt gradient comprises applying;

a first ammonium salt concentration at a first stage; and

a second ammonium salt concentration at a second stage.

2. The method of claim 1 wherein the salt includes ammonium sulfite.

3. The method of claim 1 wherein the salt includes ammonium bisulfite.

4. The method of claim 1 wherein the salt includes ammonium sulfate.

5. The method of claim 1 wherein the first concentration is greater than the second concentration.

6. The method of claim 5 wherein the applying a first ammonium salt concentration at a first stage comprises spraying absorption circulation liquid on the flue gas in a sulfur dioxide absorption process.

7. The method of claim 6 wherein the applying a second ammonium salt concentration at a second stage comprises spraying absorption circulation liquid on the flue gas in the sulfur dioxide absorption process.

8. The method of claim 5 wherein the applying a first ammonium salt concentration at a first stage comprises spraying fine particle washing circulation liquid on the flue gas in a fine particle washing process.

9. The method of claim 8 wherein the applying a second ammonium salt concentration at a second stage comprises spraying fine particle washing circulation liquid on the flue gas in the fine particle washing process.

10. A method for controlling aerosol production during absorption of sulfur dioxide from a flue gas, the method comprising:

applying an ammonium salt gradient to the flue gas; and

applying a reaction condition gradient to the flue gas.

11. The method of claim 10 wherein the applying a reaction condition gradient comprises providing:

a first temperature at a first stage; and

a second temperature at a second stage.

12. The method of claim 11 wherein the first temperature is greater than the second temperature.

13. The method of claim 11 wherein the providing a first temperature at a first stage comprises setting a first temperature in a sulfur dioxide absorption process.

14. The method of claim 11 wherein the providing a second temperature at a second stage comprises setting a second temperature in a fine particle washing process.

15. The method of claim 10 wherein the applying a reaction condition gradient comprises providing:

a first pH at a first stage; and

a second pH at a second stage.

16. The method of claim 15 wherein the first pH is greater than the second pH.

17. The method of claim 15 wherein the providing a first pH at a first stage comprises spraying absorption circulation liquid on the flue gas in a sulfur dioxide absorption process.

18. The method of claim 15 wherein the providing a second pH at a second stage comprises spraying absorption circulation liquid on the flue gas in the sulfur dioxide absorption process.

19. The method of claim 15 wherein the providing a first pH at a first stage comprises spraying fine particle washing circulation liquid on the flue gas in a fine particle washing process.

20. The method of claim 15 wherein the providing a second pH at a second stage comprises spraying fine particle washing circulation liquid on the flue gas in the fine particle washing process.

21. The method of claim 10 wherein:

the reaction condition is a temperature gradient defined by an absorption temperature and a washing temperature; and

the applying a reaction condition gradient includes;

controlling the absorption temperature and the washing temperature to reduce an energy consumption;

maintaining an absorption efficiency;

maintaining a limit on ammonia escape; and

maintaining a limit on aerosol escape.

22. The method of claim 21 wherein the absorption temperature is in the range 30°

C. to 70°

C.

23. The method of claim 22 wherein the absorption temperature is in the range 35°

C. to 60°

C.

24. The method of claim 23 wherein the absorption temperature is in the range 45°

C. to 55°

C.

25. The method of claim 21 wherein the washing temperature is in the range 28°

C. to 68°

C.

26. The method of claim 25 wherein the washing temperature is in the range 30°

C. to 55°

C.

27. The method of claim 26 wherein the washing temperature is in the range 40°

C. to 50°

C.

28. A method for controlling aerosol production during absorption of sulfur dioxide from a flue gas, the method comprising:

applying an ammonium salt gradient to the flue gas;

cooling and purifying the flue gas;

after the cooling and purifying, absorbing sulfur dioxide; and

,

after the absorbing, removing the flue gas with a fine particle washing circulation liquid;

wherein;

the applying an ammonium salt gradient is performed after the purifying and cooling; and

the absorbing and the removing both include;

spraying ammonium sulfite; and

spraying ammonium sulfate.

29. The method of claim 28 wherein:

the absorbing includes spraying absorption circulation liquid on the flue gas; and

the fine particle washing circulation liquid has;

a pH that is lower than a pH of the absorption circulation liquid; and

an ammonium sulfite concentration less than an ammonium sulfite concentration of the absorption circulation liquid.

30. The method of claim 28 wherein:

the absorbing includes;

spraying an absorption circulation liquid at a lower stage;

spraying an absorption circulation liquid at an upper stage that is downstream, relative to the flue gas, from the lower stage; and

the absorption circulation liquid at one or both of the lower and upper stages;

comprises;

0.15%-4.95% ammonium sulfite; and

5%-38% ammonium sulfate; and

has a pH value in the range 4-6.6;

wherein the ammonium sulfite concentration of the upper stage absorption circulation liquid is lower than the ammonium sulfite concentration of the lower stage of the absorption circulation liquid.