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Combined method for removing sulfur dioxide and nitrogen oxides from flue gas

A technology for combined removal and nitrogen oxide compound removal, applied in the fields of chemical industry and environmental protection, can solve the problems of ozone layer depletion, absorbing liquid polluting the environment, and high process costs, achieving less pharmaceutical usage, reducing gypsum production, and avoiding secondary pollution. Effect

Inactive Publication Date: 2016-03-02
SHANGHAI JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Removal of NO from flue gas X Existing technologies include liquid absorption method, solid absorption method, catalytic reaction method and biological purification method, among which the capture agent Fe(II) (EDTA) is used in the liquid absorption method to remove NO X The effect is remarkable, but this process will generate N-S compounds, which will be decomposed into laughing gas (N 2 O), which is one of the members of the substance that produces the greenhouse effect and one of the substances that cause the depletion of the ozone layer. At the same time, the absorbed solution cannot be recycled to remove NO X , the cost of this process is high, and the waste absorption liquid pollutes the environment

Method used

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  • Combined method for removing sulfur dioxide and nitrogen oxides from flue gas
  • Combined method for removing sulfur dioxide and nitrogen oxides from flue gas
  • Combined method for removing sulfur dioxide and nitrogen oxides from flue gas

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0055] Example 1. Activated carbon catalysis, electrochemical assistance, and sodium sulfite reduction combined removal of NO from flue gas X and SO 2 effect fruit

[0056] In this example, Fe(II) (EDTA) is used as the metal complex and nut activated carbon as the catalyst to investigate the combined desulfurization and denitrification effects of this invention. It should be noted that sodium sulfite comes from SO dissolved in the metal complex solution 2 . Other detailed parameters of this case are as follows:

[0057] 1) Flue gas parameters: temperature 50°C, oxygen content 5%, NOx concentration 400mg m -3 and SO 2 Concentration 900ppm;

[0058] 2) Fe(II)(EDTA) solution: pH8, 100mM;

[0059] 3) The liquid-gas ratio is 4.0L / m 3 ;

[0060] 4) The rotating speed of the turntable is 156rpm;

[0061] 5) Perfluorosulfonic acid type proton exchange membrane;

[0062] 6) Working voltage 2V;

[0063] 7) The cathode and anode electrode materials are Ti and Ti e...

Embodiment 2

[0066] Example 2, with and without activated carbon catalysts for electrochemical assisted, sodium sulfite reduction combined removal of flue gas NO X and SO 2 Effect of effect

[0067] This case investigates the ability of electrochemically assisted, sodium sulfite to reduce nitrogen oxides and regenerate metal complex solutions with and without activated carbon. The detailed operation process and parameters of this case are as follows:

[0068] 1) Catholyte: Fe(II)(EDTA) solution containing nitrogen and oxygen;

[0069] 2) Anode area: saturated sodium sulfate solution;

[0070] 3) Cathode: cylindrical Cu sheet;

[0071] 4) Anode: cylindrical Pb sheet;

[0072] 5) Catalyst: charcoal granular activated carbon 25g;

[0073] 6) Working voltage: 1V;

[0074] 7) Perfluorosulfonic acid type proton exchange membrane.

[0075] Table 1 Comparison of reduction and regeneration time of Fe(II)(EDTA) mixed solution containing nitrogen and oxygen with and without cataly...

Embodiment 3

[0078] Example 3, the effect of the pH value of the metal complex solution on the combination of activated carbon catalysis, electrochemical assistance, and sodium sulfite reduction NO removal from flue gas X and SO 2 Impact

[0079] This example evaluates the effect of the pH value of the metal complex solution on the combined desulfurization and denitrification effects. In this embodiment, Fe(II)(EDTA) is selected as the metal complex with a concentration of 60 mM. The detailed parameters are as follows:

[0080] 1) Flue gas parameters: temperature 50°C, oxygen content 5%, NO X Concentration 400mg·m -3 and SO 2 Concentration 500ppm;

[0081] 2) The liquid-gas ratio is 1.5L / m 3 ;

[0082] 3) Working voltage 2V;

[0083] 4) The anode and cathode electrode materials are respectively Ti and Ni electrodes;

[0084] 5) Perfluorosulfonic acid type proton exchange membrane;

[0085] 6) 25g of nut granular activated carbon.

[0086] CAR joint removal of SO fro...

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Abstract

The invention discloses a method for combined removal of sulfur dioxide and nitrogen oxide in a flue gas. According to the method, the use level of quicklime in a desulfurization process (FGD (flue gas desulfurization)) is reduced according to the concentration of NOX to realize partial desulfurization, the remaining SO2 is used for directly reducing the NOX into nitrogen (N2), and meanwhile, the SO2 is oxidized into sulfate. The method comprises the following working flows of: efficiently absorbing the NOX and SO2 in the flue gas after the FGD process by using a solution containing metal complex, and meanwhile, converting the SO2 into sodium sulfite (Na2SO3); reacting the NOX with the metal complex to generate a nitrogenous oxide; reducing the nitrogenous oxide into N2 by using SO3<2-> under the action of active carbon (AC) catalysis and electrochemical assistance, and oxidizing the SO3<2-> into harmless sulfate; and regenerating a metal complex absorption solution at the same time. Along with the continuous accumulation of sodium sulfate in the regenerated absorption solution, the solution is subjected to low-temperature freezing, the sodium sulfate is separated out in the form of crystals, and the metal complex solution after recovering the sulfate is used for continuously absorbing the NOX and the SO2 to realize recycling.

Description

technical field [0001] The invention belongs to the fields of chemical industry and environmental protection, and in particular relates to a method for combined removal of sulfur dioxide and nitrogen oxides in flue gas (CAR for short). Background technique [0002] With the development of modern industry, sulfur dioxide (SO 2 ) emissions are getting worse. Atmospheric SO 2 It is the main source of acid rain, urban ozone and photochemical smog, and it is extremely harmful to human health. [0003] Nitrogen oxides (NO X ), same as SO 2 Similarly, it is one of the important pollutants causing air pollution, wherein nitric oxide (NO) content accounts for more than 95%. [0004] NO in flue gas X Emissions have brought serious harm to the natural environment and human production. The photochemical smog produced will damage the health of people and animals; affect the growth of plants and reduce the resistance of plants to diseases and insect pests; reduce the visibility of ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D53/78B01D53/60B01D53/86B01D53/96
CPCY02A50/20
Inventor 贾金平郭清彬孙同华王亚林
Owner SHANGHAI JIAOTONG UNIV