Method for removing elemental mercury in coal-fired flue gas

A coal-fired flue gas and elemental mercury technology, which is applied in the field of flue gas purification, can solve the problems of unrecoverable catalyst, large amount of absorbent, secondary pollution, etc.

Inactive Publication Date: 2016-01-13
NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the existing mercury removal technology has the following disadvantages: (1) the general reaction has a high mercury removal efficiency in an acidic environment. Once it is used in industry, the equipment will be severely corroded due to the low pH value of the operation; (2) the amount of absorbent is large , the economy is poor, and the cost of mercury removal is increased; (3) metal ions (Mn, Cr, Ag, Cu, etc.) Catalysts cannot be recycled, easily causing secondary pollution, and waste water requires additional treatment

Method used

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  • Method for removing elemental mercury in coal-fired flue gas
  • Method for removing elemental mercury in coal-fired flue gas
  • Method for removing elemental mercury in coal-fired flue gas

Examples

Experimental program
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Effect test

Embodiment 1

[0037] Example 1: Weigh 100 g of the magnetic catalyst cobalt-doped bismuth ferrite according to the ratio (the molar ratio of cobalt atoms and iron atoms in cobalt-doped bismuth ferrite is 1:9), 200 g of oxidative additive sodium persulfate, and 200 liters of high-purity water , mix the magnetic catalyst with high-purity water, ultrasonically disperse for 1 minute, adjust the pH to 6, then add a proportioned amount of oxidizing additives at room temperature, and stir mechanically for 3 minutes to prepare the absorbent.

Embodiment 2

[0038] Example 2: Weigh 50 g of the magnetic catalyst cobalt-doped bismuth ferrite (the molar ratio of cobalt atoms to iron atoms in cobalt-doped bismuth ferrite is 3:7), 50 g of cobalt / lanthanum doped bismuth ferrite (cobalt / The molar ratio of cobalt atom, lanthanum atom and iron atom in lanthanum-doped bismuth ferrite is 3:1:6), oxidative additive sodium perborate 300g, potassium hydrogen persulfate compound salt 200g, high-purity water 380 liters, magnetic The catalyst is mixed with high-purity water, ultrasonically dispersed for 2 minutes, and the pH is adjusted to 12. Then, at room temperature, a proportioned amount of oxidizing additive is added, and mechanically stirred for 4 minutes to obtain the absorbent.

Embodiment 3

[0039] Embodiment 3: Take by weighing 100g of magnetic catalyst bismuth ferrite, 300g of oxidative additive potassium hydrogen persulfate compound salt, 280 liters of high-purity water, mix magnetic catalyst with high-purity water, ultrasonically disperse for 3 minutes, adjust pH to 7, and then Under the condition of room temperature, adding the proportioning amount of oxidative additives and stirring mechanically for 5 minutes, the absorbent is prepared.

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Abstract

The invention discloses a method for removing elemental mercury in coal-fired flue gas. Removing is carried out in a spray absorber. A prepared absorbent is sprayed from the upper portion of the spray absorber for carrying out spraying on coal-fired flue gas introduced in from a smoke opening in the lower portion of the spray absorber, elemental mercury in the coal-fired flue gas sufficiently reacts with the absorbent, and conversion from the elemental mercury to divalent state mercury is achieved; the absorbent comprises an oxidation additive and a magnetic catalyst which have the mass ratio being 2-5:1, the oxidation additive is any one of or the combination of two or more of potassium peroxymonosulfate, sodium persulfate, sodium perborate and sodium percarbonate, and the catalyst is any one of or the mixture of two or more of bismuth ferrite, cobalt doped bismuth iron acid, cobalt / lanthanum doped bismuth ferrite, cobalt / strontium doped bismuth ferrite, cobalt / rubidium doped bismuth ferrite. The method has the advantages that the absorbent utilization rate is high, the catalyst can be repeatedly used, secondary pollution is avoided, operation is easy and convenient, running is stable, the product is easy to treat, and application and popularization are convenient.

Description

technical field [0001] The invention relates to a flue gas purification method, in particular to a method for removing elemental mercury in coal-fired flue gas by catalytic oxidation using a recyclable magnetic material as a catalyst, and belongs to the technical field of flue gas purification. Background technique [0002] Mercury is a three-cause substance (carcinogenic, teratogenic, mutagenic) and one of the priority pollutants. The total amount of mercury emitted into the atmosphere in the world is about 5000t per year, of which 4000t is the result of man-made, and the mercury emission in the process of coal combustion accounts for more than 30%. According to relevant regulations, the emission limit of mercury and its compounds in thermal power plants is 0.03mg / m 3 . Therefore, it is necessary to strengthen the research on the control of mercury pollution emissions from coal-fired power plants. [0003] There are three main forms of mercury in flue gas: oxidized mercu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/90B01D53/64
Inventor 赵毅马霄颖
Owner NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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