Device and method for purifying sulfur dioxide and nitrogen oxide in flue gas

Patent metadata

Field	Value
Publication number	US-10730010-B2
Application number	US-201916515634-A
Country	US
Kind code	B2
Filing date	Jul 18, 2019
Priority date	Jul 19, 2018
Publication date	Aug 4, 2020
Grant date	Aug 4, 2020

Abstract

The invention is a device and method for purifying sulfur dioxide and nitrogen oxide in flue gas with an electrolysis-chemical advanced oxidation enhanced ammonia method. The device includes a thermal activation reactor, ammonium hydroxide storage tank, absorption tower, electrolytic bath and crystallization separator. The method takes raw material part of an ammonium sulfate solution that is a reaction product of ammonia and sulfur oxide in flue gas, and an ammonium persulfate solution prepared by electrolysis of an electrolytic bath as an oxidant to enhance the efficiency of purifying sulfur dioxide and nitrogen oxide in the flue gas with an ammonia method. A thermal activation reactor activates an ammonium persulfate containing solution to generate a strong oxidizing SO4. − , so that NO x and SO 2 in the flue gas may be more efficiently converted into a product having higher solubleness for enhanced removal of sulfur dioxide and nitrogen oxide in the flue gas.

First claim

What is claimed is:

1. A device for purifying sulfur dioxide and nitrogen oxide in flue gas with an electrolysis-chemical advanced oxidation enhanced ammonia method, comprising a thermal activation reactor ( 1 ), an ammonium hydroxide storage tank ( 2 ), an absorption tower ( 3 ), an entire electrolytic cell ( 4 ) and a crystallization separator ( 5 ), wherein a shell side inlet of the thermal activation reactor ( 1 ) communicates with high temperature flue gas, and an outlet of the thermal activation reactor ( 1 ) communicates with a gas inlet of the absorption tower ( 3 ); a tube side inlet of the thermal activation reactor ( 1 ) communicates with an outlet of the entire electrolytic cell ( 4 ), and a first power pump ( 6 ) is disposed on a tube line; a tube side outlet of the thermal activation reactor ( 1 ) communicates with a liquid inlet of the absorption tower ( 3 ), the ammonium hydroxide storage tank ( 2 ) also communicates with the liquid inlet of the absorption tower ( 3 ), and a second power pump ( 6 ) is disposed on the tube line; a circulating absorption liquid outlet of the absorption tower ( 3 ) communicates with a spray atomization system, and a third power pump ( 6 ) is disposed on the tube line; and a liquid outlet of the absorption tower ( 3 ) respectively communicates with the crystallization separator ( 5 ) and the entire electrolytic cell ( 4 ).

2. The device according to claim 1 , wherein the thermal activation reactor ( 1 ) is of a shell-and-tube structure, and is made of a stainless steel or a ceramic.

3. The device according to claim 1 , wherein a cathode chamber and an anode chamber of the entire electrolytic cell ( 4 ) are separated by a plate-like cation exchange membrane; and an anode of the entire electrolytic cell ( 4 ) uses a pure platinum, titanium-based platinum-plated or graphite electrode, and a cathode of the entire electrolytic cell ( 4 ) uses a graphite or titanium electrode.

4. The device according to claim 3 , wherein the tube side inlet of the thermal activation reactor ( 1 ) communicates with the anode of the entire electrolytic cell ( 4 ).

5. A method for purifying sulfur dioxide and nitrogen oxide in flue gas with an electrolysis-chemical advanced oxidation enhanced ammonia method, comprising the following steps: first introducing high temperature flue gas containing the sulfur dioxide and the nitrogen oxide to a shell side of a thermal activation reactor ( 1 ) for circulation, wherein a tube side of the thermal activation reactor ( 1 ) circulates an ammonium persulfate containing solution obtained by electrolysis of an entire electrolytic cell ( 4 ), the high temperature flue gas and the ammonium persulfate containing solution implement indirect heat exchange in the thermal activation reactor ( 1 ), and ammonium persulfate is activated to generate a strong oxidizing SO 4 . − ; and then, inputting the flue gas to an absorption tower ( 3 ) via a gas tube line, inputting the SO 4 . − containing solution, subject to the heat exchange and activation, to the absorption tower ( 3 ) via a liquid delivery tube line, and simultaneously inputting ammonium hydroxide to the absorption tower ( 3 ) via the liquid delivery tube line from an ammonium hydroxide storage tank ( 2 ), wherein as a flue gas absorption liquid, the SO 4 . − containing solution and the ammonium hydroxide contact with SO 2 and NO x in the flue gas by spray atomization for reaction, to oxidatively remove the SO 2 and the NO x in the flue gas, the SO 2 and the NO x are converted into a product having higher solubleness such as SO 3 , H 2 SO 4 , NO 2 and HNO 3 , and simultaneously react with the ammonium hydroxide in the absorption liquid to generate a solution containing ammonium sulfate and ammonium nitrate, one part of the solution containing the ammonium sulfate and the ammonium nitrate serves as a raw material solution for generating ammonium persulfate by electrolysis of the entire electrolytic cell ( 4 ), and the other part of the solution containing the ammonium sulfate and the ammonium nitrate is input to a crystallization separator ( 5 ) to obtain an ammonium sulfate and ammonium nitrate product.

6. The method according to claim 5 , wherein the raw material solution for generating the ammonium persulfate by the electrolysis in the entire electrolytic cell ( 4 ) contains 20-45 wt % of ammonium sulfate.

7. The method according to claim 5 , wherein anodic current density of the entire electrolytic cell ( 4 ) is 0.8 A/cm 2 or more, electrolysis time is 3-6 h, and pH of the anode chamber is maintained at 3-7.

Assignees

• Univ Kunming Science & Technology

Inventors

• Tian Senlin
• Song Yuxin
• Huang Jianhong
• Hu Xuewei
• Li Yingjie
• Ning Ping

Classifications

• B01D53/60 Primary

  Simultaneously removing sulfur oxides and nitrogen oxides · CPC title

• B01D53/96

  Regeneration, reactivation or recycling of reactants · CPC title

• B01D2258/0283

  Flue gases · CPC title

• B01D2251/206

  Ammonium compounds · CPC title

• B01D2257/404

  Nitrogen oxides other than dinitrogen oxide · CPC title