A method for removing elemental mercury in coal-fired flue gas

A coal-fired flue gas and elemental mercury technology, applied in the field of flue gas purification, can solve the problems of low operating pH, increased cost of mercury removal, and large amount of absorbent

Inactive Publication Date: 2018-01-02
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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  • A method for removing elemental mercury in coal-fired flue gas
  • A method for removing elemental mercury in coal-fired flue gas

Examples

Experimental program
Comparison scheme
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 oxidizing 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 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-doped bismuth ferrite) The mol ratio of cobalt atom, lanthanum atom, iron atom in lanthanum-doped bismuth ferrite is 3:1:6), oxidizing 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

A method for removing elemental mercury in coal-burning flue gas. The removal is carried out in a spray absorption tower. The prepared absorbent is sprayed down from the upper part of the spray absorption tower, and the mercury introduced from the lower part of the spray absorption tower is sprayed. The coal-fired flue gas is sprayed to fully react the elemental mercury in the coal-fired flue gas with the absorbent to realize the conversion of elemental mercury to divalent mercury; the absorbent includes oxidizing additives and magnetic catalysts, oxidizing The mass ratio of the additive to the magnetic catalyst is 2 to 5:1, and the oxidizing additive is one or more combinations of potassium hydrogen persulfate, sodium persulfate, sodium perborate, and sodium percarbonate, and the catalyst It is one or more mixtures of bismuth ferrite, cobalt doped bismuth ferrite, cobalt / lanthanum doped bismuth ferrite, cobalt / strontium doped bismuth ferrite, cobalt / rubidium doped bismuth ferrite. The invention has the characteristics of high utilization rate of the absorbent, repeated use of the catalyst, no secondary pollution, simple and convenient operation, stable operation, easy handling of the product, and convenient popularization and application.

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-causing substance (carcinogenic, teratogenic, and mutagenic), and it is also one of the priority pollutants. The total amount of mercury emitted into the atmosphere in the world is about 5000t every 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...

Claims

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Application Information

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