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Coal-fired mercury discharge control method based on semi-dry process

An emission control, semi-dry technology, applied in separation methods, chemical instruments and methods, dispersed particle separation, etc., can solve the problems of low total mercury removal rate, difficult to popularize and apply, difficult to remove, etc., and achieve easy adsorption. , improve the utilization rate, the effect of large reactivity

Inactive Publication Date: 2004-04-14
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in general, the removal rate of these methods for the total mercury in the flue gas of coal-fired power plant boilers is too low to be popularized and applied.
[0010] At present, mercury pollution control technology has been applied in the waste incinerator industry in foreign countries, but my country has no industrial equipment for removing mercury from flue gas.
In view of the low concentration of mercury in coal-fired flue gas and the difficulty of removal, foreign technologies in this field are in the stage of industrial testing and pilot testing, and have not yet been widely promoted.

Method used

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  • Coal-fired mercury discharge control method based on semi-dry process
  • Coal-fired mercury discharge control method based on semi-dry process
  • Coal-fired mercury discharge control method based on semi-dry process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Such as figure 1 , a coal-fired power plant boiler, the flue gas flow rate is 8.31×10 5 N m 3 / h, the mercury content in the generated flue gas is 6.8μg / Nm 3 . The additive is selected as HCl (excessive HCl can be removed in the desulfurization device and will not cause secondary pollution), the injection amount of HCl / Hg is 600, and it is injected when the flue gas temperature is 900°C, and there is oxygen in the flue gas Under this condition, a part of elemental mercury is oxidized to oxidized mercury, and the speciation analysis is carried out by the Ontario-Hydro method. The result shows that the ratio of elemental mercury to oxidized mercury is 80%; the reaction chemical equation is as follows:

[0037]

[0038] When the flue gas temperature is 150°C, a solution containing 0.5% hydrogen peroxide is sprayed into the flue gas through the spraying device, and the liquid flow rate is 600Kg / h. The hydrogen peroxide is decomposed by heat to generate active oxyg...

Embodiment 2

[0048] Such as figure 1 Show, the flue gas flow rate, the content of mercury in the flue gas are the same as in Example 1, and the additive is selected as FeCl 3 , the injection amount of FeCl 3 / Hg is 1600, sprayed when the flue gas temperature is 800°C, oxidizes a part of elemental mercury to oxidized mercury, and uses the Ontario-Hydro method for speciation analysis, the result shows that the ratio of elemental mercury to oxidized mercury is 50%; The reaction chemical equation is as follows:

[0049]

[0050] When the flue gas temperature is 160°C, the solution containing 0.4% sodium hypochlorite is sprayed into the flue gas through the spraying device, and the liquid flow rate is 600Kg / h, so that the ratio of elemental mercury to be oxidized to mercuric chloride or mercuric oxide is increased to 80%. At the same time, the temperature of the flue gas is reduced to 100 degrees; then, FeCl is injected into the flue gas 3 Impregnated modified vermiculite adsorbent, t...

Embodiment 3

[0052] Such as figure 2 shown, with figure 1 Compared with not spraying additives. For a coal-fired boiler, the flue gas output is about 6×10 5 N m 3 / h, the total mercury content in the flue gas produced is about 3.8μg / Nm 3 . When the flue gas temperature is 150°C, spray a solution containing 0.2% chlorine water into the flue gas through the spraying device, and the liquid flow rate is 400Kg / h, and the ratio of elemental mercury to mercuric chloride or mercuric oxide is increased to 86%. , while the temperature of the flue gas is reduced to 100 degrees; then the MnO 2 Impregnated modified activated carbon adsorbent, sprayed at a rate of C / Hg 12000, to convert elemental mercury into Hg 2 MnO 2 This adsorption process is a relatively strong chemical adsorption process, and a new compound Hg is generated after adsorption. 2 MnO 2 :

[0053]

[0054] Mercury is in a low-valence state in this compound, and electrons are transferred from mercury to manganese insid...

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Abstract

The invention discloses a kind of coal mercury discharging control method which is based on semi-drying method. Sprays additive into the boiler smoke, oxidizes the elemetary mercury into mercuric oxide easy to remove; then sprays liquid including oxidant into smoke and oxidizes the mercury, and the temperature is decreased and forms the low temperature for high efficiency absorption; sprays absorption agent into cooled smoke, eliminates the mercuric oxide and mercury; the solid particle containing mercury is collected through electricity deduster or baggage dedusting device. The invention reduces the cost of operation.

Description

technical field [0001] The invention relates to a coal-fired mercury emission control method based on a semi-dry method. Background technique [0002] Mercury is a familiar environmental pollutant. After entering the atmosphere and water from pollution sources, mercury in various forms can be converted into inorganic divalent mercury, and then converted into methylmercury under biological action. Methylmercury accumulates in aquatic organisms such as algae and fish, and directly endangers human health through the food chain. The intrusion of methylmercury in the environment into various animals and plants increases the chance, scope and way of methylmercury intrusion into the human body, and leads to more lasting harm to the human body. The main source of mercury environmental pollution is man-made mercury pollution. According to statistics, the total annual emissions to the atmosphere around the world is about 5,000 tons, of which 4,000 tons are ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/64
Inventor 骆仲泱周劲松王勤辉岑可法方梦祥高翔施正伦程乐鸣王树荣余春江倪明江
Owner ZHEJIANG UNIV
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