Method for removing hydrargyrum from coal burning boiler flue gas by ozone oxidation

A technology for ozone oxidation and coal-fired boilers, applied in chemical instruments and methods, separation methods, and separation of dispersed particles, etc., can solve problems such as difficult large-scale popularization and application, reduced boiler efficiency, and low total mercury removal efficiency of coal-fired boilers

Active Publication Date: 2006-05-10
ZHEJIANG UNIV
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Problems solved by technology

[0008] The adsorption of fly ash is used to remove mercury. The fly ash produced by coal combustion has adsorption effect on mercury. The higher carbon content is beneficial to the adsorption of mercury, but the increase of carbon content in fly ash will reduce the boiler efficiency and affect the fly ash. Resistivity, reduce the collection efficiency of electrostatic precipitator for fly ash
In addition, the removal efficiency of this method for total mercury in coal-fired boilers is low, and it is difficult to apply it on a large scale.

Method used

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  • Method for removing hydrargyrum from coal burning boiler flue gas by ozone oxidation
  • Method for removing hydrargyrum from coal burning boiler flue gas by ozone oxidation

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specific Embodiment 1

[0027] In specific embodiment 1, it is the arrangement mode of dust-laden wet scrubbing by ozone oxidation of coal-fired boiler flue gas to remove mercury, and the implementation method is as follows figure 1 shown. After the air is dried and purified, it is sent to the dry and filtered oxygen generator 2, and the generated oxygen is sent to the ozone generator 3 to prepare high-concentration ozone, and the ozone is sent to the dusty smoke with a temperature of 110°C before the electrostatic precipitator 5 after the air preheater Road, the amount of injection according to the flue gas NO concentration according to O 3 / NO molar ratio of 1.1:1 is adjusted from time to time to ensure a reaction time of at least 0.5s. The nozzle adopts porous grid injection, and the injection position is 1m away from the flue gas outlet of the air preheater. After passing through the electrostatic precipitator 5, it enters the wet scrubber 7, and the Hg 2+ Dissolving and absorbing, using H 2 ...

specific Embodiment 4

[0030] In the specific embodiment 4, it is the dust-free layout method of the ozone oxidation of coal-fired boiler flue gas to remove mercury, and the realization method is as follows figure 2 shown. Send ozone into the dust-free environment with a temperature of 110°C after the electrostatic precipitator, and the amount of ozone sent is O according to the concentration of NO 3 The / NO molar ratio is selected as 1.2:1. The injection position is after the dust collector and away from the washing tower inlet. The injection position can be determined according to the actual pipeline to ensure a response time of at least 0.5s. Divalent Hg 2+ Absorption and removal are carried out after entering the scrubber. The washing tower uses water or lye as the absorbent, and the washing tower is a spray tower or a packed tower. The lye used as absorbent is calcium hydroxide, but also potassium hydroxide or sodium hydroxide. Other steps are identical with specific embodiment 1.

[0031...

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Abstract

The invention provides a method for controlling the hydrargyrum exhaustion of boiler smoke. The method comprises: ejecting ozone into the low-temperature section of smoke channel of boiler whose temperature ranges from 110-150Deg. C; oxygenizing the nonvalent Hg which is not dissolved in water into bivalent Hg; washing the smoke in the washing tower to dissolve the bivalent Hg in water; adding H2S fixation agent into solution to generate HgS deposition from bivalent Hg. Compared to the Hg exhaustion removing efficiency in present fire coal power station which is lower than 50-50%, the total Hg removing efficiency of said invention can be over 80%.

Description

technical field [0001] The invention relates to the technical field of environmental protection, in particular to a method for controlling mercury emission in boiler flue gas, which is suitable for coal-fired and oil-fired boilers and industrial kilns. Background technique [0002] Mercury is a toxic trace heavy metal element. After various forms of mercury enter the atmosphere and water from pollution sources, they form methylmercury under biological action. Methylmercury can accumulate in water organisms such as algae and fish, and enter the human body through the biological chain. Since mercury cannot be detoxified and discharged in the human body, it will cause long-term harm to human health. The total amount of mercury emitted to the atmosphere globally is 5,000 tons per year, of which 4,000 tons are anthropogenic. The sources of man-made emissions of mercury are mainly factories and mines producing mercury, smelting of non-ferrous metals, chlor-alkali industry, electr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/64
Inventor 岑可法周俊虎王智化刘建忠杨卫娟周志军黄镇宇程军
Owner ZHEJIANG UNIV
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