Combined desulfuration, denitration, and demercuration apparatus and method using semi-dry process in circulating fluidized bed

Patent metadata

Field	Value
Publication number	US-9656206-B2
Application number	US-201314892150-A
Country	US
Kind code	B2
Filing date	Oct 23, 2013
Priority date	Oct 15, 2013
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

A combined desulfuration, denitration, and demercuration apparatus and method using a semi-dry process in a circulating fluidized bed. The apparatus comprises a flue ( 2 ) and a circulating fluidized bed reaction column ( 8 ) connected in sequence, the flue ( 2 ) being connected to a bottom inlet of the circulating fluidized bed reaction column ( 8 ). The flue ( 2 ) is further connected to an ozone generation apparatus ( 1 ). The ozone distributor ( 1 ) feeds ozone in the flue ( 2 ) and sends oxidized flue gas into the circulating fluidized bed reaction column ( 8 ), so that the SO 2 , high-valence NO x , and Hg 2+ contained in the flue gas are removed through reactions with a Ca-based absorbent under the effect of atomized water in the reaction column ( 8 ).

First claim

The invention claimed is:

1. A combined desulfuration, denitration, and demercuration apparatus using semi-dry process in circulating fluidized bed, comprising a flue and a circulating fluidized bed reaction column connected in sequence, the flue being connected to a bottom inlet of the circulating fluidized bed reaction column; the flue is further connected to an ozone generation apparatus.

2. The apparatus according to claim 1 , further comprising an upper outlet on the circulating fluidized bed reaction column connected to a cyclone separator, and a first outlet of a separation hopper of the cyclone separator connected to a recycled material inlet of the circulating fluidized bed reaction column.

3. The apparatus according to claim 2 , wherein the upper outlet of the circulating fluidized bed reaction column is connected in tangential direction to the cyclone separator.

4. The apparatus according to claim 2 , wherein the first outlet is connected to the recycled material inlet through an air chute.

5. The apparatus according to claim 2 , wherein the cyclone separator is connected to a deduster, and a second outlet of the separation hopper is communicated with a separation hopper of the deduster and an ash bin simultaneously.

6. The apparatus according to claim 5 , further comprising a purged gas outlet of the deduster is connected to a chimney.

7. The apparatus according to claim 1 , further comprising an ozone distributor arranged at the connecting position of the ozone generation apparatus and the flue.

8. The apparatus according to claim 2 , wherein the bottom of the circulating fluidized bed reaction column has a Venturi structure, a feed inlet, a recycled material inlet and a water spray nozzle are arranged in a Venturi expansion section of the Venturi structure; and the water spray nozzle is mounted along the downstream direction of where the flue gas would travel.

9. The apparatus according to claim 8 , further comprising an absorbent warehouse connected to the feed inlet through a screw conveyor.

10. A method for removing various pollutants by the combined desulfuration, denitration, and demercuration apparatus using semi-dry process in circulating fluidized bed comprising the steps of:
1) Spraying ozone into a flue comprising flue gas, so that NO and Hg 0 in the flue gas are oxidized to high-valence NO x and Hg 2+ in the flue; and
2) The oxidized flue gas is transferred to a circulating fluidized bed reaction column, so that the SO 2 , high-valence NO x and Hg 2+ contained in the flue gas are removed through reactions with a Ca-based absorbent under the effect of atomized water in the reaction column.

11. The method according to claim 10 , further comprising the reacted Ca-based absorbent returns to the reaction column through an air chute after being separated by a cyclone separator to achieve multiple cycles, and the flue gas is discharged after dust is removed by a deduster.

12. The method according to claim 10 , further comprising that, in step 1), the molar ratio of ozone sprayed into the flue to nitrogen oxide in the flue gas is 0.5-2.5 and the reaction time is not less than 0.5 seconds.

13. The method according to claim 10 , further comprising that, in step 2), the Ca-based absorbent is added in a ratio that makes the molar ratio of Ca/(S+N) to be 1.1-2.0.

14. The method according to claim 10 , further comprising the contents of sulfur oxides, nitrogen oxides, and mercury in the treated flue gas are controlled by adjusting the addition amount of the Ca-based absorbent.

15. The method according to claim 10 , further comprising the amount of water is adjusted according to the flue gas temperature at the outlet of a circulating fluidized bed reaction column to ensure the temperature in the column is kept above the dew point of the flue gas.

16. The method according to claim 10 , further comprising that a differential pressure between the inlet and outlet of the circulating fluidized bed reaction column is controlled by adjusting the amount of the recycled material.

Assignees

• Inst Process Eng Cas
• Beijing Zstc Env Eng Co Ltd

Inventors

• Zhu Tingyu
• Xu Wenqing
• Ye Meng
• Zhao Ruizhuang

Classifications

• B01D2257/404

  Nitrogen oxides other than dinitrogen oxide · CPC title

• B01D2251/404

  of calcium · CPC title

• B01D2257/302

  Sulfur oxides · CPC title

• B01D2251/104

  Ozone · CPC title

• B01D53/83 Primary

  with moving reactants · CPC title