Method for controlling aerosol production during absorption in ammonia desulfurization

• US 10,449,488 B2
• Filed: 03/29/2019
• Issued: 10/22/2019
• 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:
  US16/369,146
• Publication Number:
  US 20190270048A1
• Time in Patent Office: 207 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. Apparatus for controlling aerosol production in ammonia desulfurization, the apparatus comprising:

a gas purification and removal system that is configured to apply an ammonium salt gradient to flue gas;

an oxidation system configured, to form the ammonium salt gradient, to provide;

to a fine particle washing circulation liquid an ammonium solution of a first composition; and

p2 to an absorption circulation liquid an ammonium solution of a second composition;

an auxiliary system;

a tower that;

houses the gas purification and removal system; and

includes;

a pre-washing zone;

an absorption zone; and

a fine particle control zone;

a plurality of spraying layers, each of the pre-washing zone, the absorption zone, and the fine particle control zone including a spraying layer of the plurality of spraying layers; and

a plurality of demister layers, wherein a demister layer of the plurality of demister layers is disposed in the fine particle control zone.

2. The apparatus of claim 1 further comprising a component disposed between the absorption zone and the pre-washing zone that allows only gas to pass;

and

wherein the tower is configured to provide divisional control of solution compositions to the spraying layers.

3. The apparatus of claim 2 wherein

a demister layer of the plurality is disposed in each spraying layer of the pre-washing zone and the absorption zone.

4. The apparatus of claim 3 wherein a demister of the plurality of demister layers includes a baffle.

5. The apparatus of claim 3 wherein a demister of the plurality of demister layers includes a ridge.

6. The apparatus of claim 3 wherein a demister of the plurality of demister layers includes filler.

7. The apparatus of claim 3 wherein a demister of the plurality of demister layers includes a wire mesh.

8. The apparatus of claim 3 wherein a demister of the plurality of demister layers includes a structure selected from the group consisting of:

a baffle;

a ridge;

filler;

wire mesh; and

a combination of one or more of a baffle;

a ridge;

filler; and

wire mesh.

9. The apparatus of claim 2 wherein:

in each spraying layer of the absorption zone;

a liquid-to-gas ratio is not less than 0.2 L/Nm₃; and

spray coverage is not less than 110%; and

,

in each spraying layer of the fine particle control zone;

a liquid-to-gas ratio is not less than 0.1 L/Nm₃; and

spray coverage is not less than 105%.

10. The apparatus of claim 2 wherein the tower is configured to:

cool and wash the flue gas using circulation washing liquid in the pre-washing zone, and simultaneously increase a concentration of the circulation washing liquid;

pass the flue gas through the absorption zone, in which the flue gas is washed and desulfurized by absorption circulation liquid;

pass the flue gas through the fine particle control zone, in which fine particles are removed by a fine particle circulation washing liquid;

discharge the flue gas;

replenish the circulation washing liquid in the pre-washing zone from the fine particle circulation washing liquid;

rinse fouling on a tower wall;

replenish the absorption circulation liquid;

oxidize the absorption circulation liquid in the oxidation system, and

draw circulation liquids with different compositions from different sections of the oxidation system for distribution to the different zones.

11. The apparatus of claim 10 wherein the fine particle circulation washing liquid is a majority constituent of circulation washing liquid replenishment fluids.

12. The apparatus of claim 10 wherein the tower is configured to rinse fouling by spraying fine particle circulation washing liquid.

13. The apparatus of claim 10 wherein the tower is configured to rinse fouling by spraying process water.

14. The apparatus of claim 10 wherein the absorption circulation liquid is replenished by liquid from a fine particle control zone.

15. The apparatus of claim 10 wherein the absorption circulation liquid is replenished by process water.

16. The apparatus of claim 15 wherein the process water is replenished from liquid from the fine particle control zone.

17. The apparatus of claim 10 further comprising a drying device that is configured to:

receive absorption liquid; and

produce a solid product that includes an ion from a circulation liquid.

18. The apparatus of claim 17 wherein the ion is chloride.

19. The apparatus of claim 18 wherein the drying device is configured to reduce the circulation liquid chloride ion concentration to 10,000-31,000 mg/L.

20. The apparatus of claim 17 wherein the ion is fluoride.

21. The apparatus of claim 20 wherein the drying device is configured to reduce the circulation liquid fluoride ion concentration to 300-3000 mg/L.

22. The apparatus of claim 10 wherein the tower is configured to spray, in a spraying layer in the absorption zone, absorption circulation liquid having a mass fraction ratio of ammonium sulfate to ammonium sulfite that is in the range 1.5-199 to 1.

23. The apparatus of claim 10 wherein the tower is configured to spray, in a spraying layer in the fine particle absorption zone, fine particle circulation washing liquid having a mass fraction ratio of ammonium sulfate to ammonium sulfite that is in the range 3-1999 to 1.

24. Apparatus for controlling aerosol production in ammonia desulfurization, the apparatus comprising:

a gas purification and removal system that is configured to apply an ammonium salt gradient to flue gas;

an oxidation system; and

an auxiliary system;

wherein the oxidation system;

includes a plurality of sections, each section corresponding to an ammonium solution of a different composition.

25. The apparatus of claim 24 wherein each section is defined by a layer of the oxidation system.

26. The apparatus of claim 24 wherein each section is defined by a component of the oxidation system.

27. The apparatus of claim 24 wherein each section occupies a different position in the oxidation system.

28. The apparatus of claim 24 wherein the oxidation system includes 1-5 layers of gas-liquid dispersion enhancers.

29. The apparatus of claim 24 wherein the oxidation system includes a liquid stage having a height greater than 3 m.

30. The apparatus of claim 29 wherein the oxidation system is configured to provide not less than 20% excess oxidation air.