Mercury removal for smoke desulfurizing system by fortified wetting method

A wet flue gas desulfurization and flue gas technology, applied in chemical instruments and methods, separation methods, dispersed particle separation, etc., can solve the problems of secondary pollution, elimination of mercury efficiency, low mercury removal efficiency, etc. The effect of reducing operating costs, thorough treatment, and solving the problem of secondary pollution

Inactive Publication Date: 2007-01-17
SHANGHAI JIAO TONG UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

However, the existing wet desulfurization system for mercury removal still has the following problems: 1) Because the elemental mercury in the flue gas is difficult to dissolve in water, when the mercury in the flue gas mostly exists in the form of elemental mercury, the mercury removal efficiency of this method is not high. High; 2) Di

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0023] Example 1 (Using elemental bromine as a gas-phase oxidant)

[0024] The gas-phase oxidation effect of bromine molecules on elemental mercury: Take 2mL of liquid elemental bromine (analytical purity, >98%), put it into a 50mL glass vaporization bottle (with inlet and outlet pipes), and vaporize it with a water bath device The temperature of the bottle is controlled at about 2°C. The dry air is continuously passed through the vaporization bottle containing liquid bromine at a flow rate of 5-50ml / min, and the bromine vapor is taken out and mixed with the air to form a mixed gas with a concentration of about 2%.

[0025] Using a similar method to the above, using dry air to prepare a concentration of about 100μg / m 3 The elemental mercury vapor, the flow rate of mercury-containing gas is 10-30L / min.

[0026] The above two gases are rapidly mixed during the reaction and flow through the reactor. The reactor uses a three-necked flask with a volume of 1000 mL and is equipped with a...

Example Embodiment

[0033] Example 2 (Using bromine element as a gas-phase oxidant, oxidation reaction involving fly ash)

[0034] The gas distribution conditions used are the same as those of the reaction device in Example 1, but 1g of coal-fired fly ash of about 200 mesh is added to the reactor in advance, and the fly ash is evenly dispersed in the airflow by a fan installed inside the reactor. In order to prevent fly ash from being carried out of the reactor by the gas flow, a layer of glass wool filter layer is added at the gas outlet.

[0035] The experiment was carried out with a method similar to Example 1, at a temperature of 120°C, a gas residence time of 6 seconds, and a bromine concentration of 10 mg / m 3 Under the conditions, the oxidation rate of elemental mercury can reach 95%. It can be seen that the presence of fly ash can significantly improve the oxidation efficiency of elemental mercury.

[0036] After washing with the alkaline solution in the absorption bottle, the divalent mercury...

Example Embodiment

[0037] Example 3 (using calcium hypochlorite as oxidant)

[0038] A quartz tube with a diameter of 20 mm and a length of 500 mm is used as the reactor, with a 200 mm water jacket cooling device downstream, heated by a tubular heating furnace, and a vertical settling furnace. Use the simulated flue gas prepared on site ([NO]=300mg / m 3 , [NO 2 ]=5mg / m 3 , [Hg 0 ]=100μg / m 3 , [SO2]=2000mg / m 3 , The rest is air), 800ml / min of gas flow continuously through the reactor, and through the total mercury, Hg in the reactor outlet gas 0 Concentration to determine the effect.

[0039] The massive calcium hypochlorite (analytical grade) was ground and sieved to obtain fine particles of about 200 meshes. The calcium hypochlorite powder was added into the reaction tube using a micro feeder at a feed rate of 2 g / h. When the temperature of the reaction tube is 600 ℃ and the reaction is stable, the outlet gas after cooling [Hg 0 ] Is 12μg / m 3 , So the oxidation rate of elemental mercury reaches 88%....

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PUM

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Abstract

A process for intensifying the Hg removing action of a wet fume desulfurizing system includes such steps as spraying chemical oxidant into the fume generated by burning coal, gas-phase (or catalytic) oxidizing reaction to oxidize Hg, absorbing the mercury oxide along with the 2-valence Hg in the fume by desufurizing liquid, adding the S-contained chemical additive to said desulfurizing liquid, and converting the Hg ions in desulfurizing liquid to stable Hg compound.

Description

technical field [0001] The invention relates to a method for strengthening the mercury removal effect of a wet flue gas desulfurization system. By oxidizing the elemental mercury in the flue gas and inhibiting the reduction and release of mercury ions in the desulfurization liquid, the wet desulfurization system can effectively remove mercury from the flue gas. The mercury has a high removal efficiency and converts the captured mercury into stable mercury sulfide, so as to achieve a more thorough treatment of flue gas mercury. Background technique [0002] Mercury has serious physiological toxicity. In its "Global Mercury Status Assessment" report published in February 2003, the United Nations Environment Program warned against the global mercury pollution problem. Since coal contains a certain amount of mercury, the use (mainly combustion) of a large amount of coal is one of the main causes of mercury pollution. For this reason, many countries have begun to pay attention t...

Claims

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Application Information

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IPC IPC(8): B01D53/64B01D53/50
Inventor 晏乃强吴忠标贾金平徐新华汪大翚
Owner SHANGHAI JIAO TONG UNIV
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