Method for removing fine particles and heavy metals in coal fume

A coal-fired flue gas, fine particle technology, applied in chemical instruments and methods, solid separation, cyclone devices, etc., can solve the problems of inability to achieve Coulomb condensation effect, negligible electric charge, and insignificant effect, and achieve good mercury removal. effect, increase the degree of mixing, and increase the size of the structure

Active Publication Date: 2012-11-14
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
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Problems solved by technology

Due to the charging speed of large particles, and the charge occupancy is much higher than that of PM 2.5 Fine particles, under the conditions of limited charge generation and residence time in the agglomerator or coagulation electric field, the actual charge that the fine particles can obtain is insignificant, resulting in the fact that the fine particles that should be condensed cannot achieve a significant charge due to too little charge. Coulomb condensation effect
In addition, if it is necessary to add an Indigo coalescer or an electrocoagulation parallel field before the electrostatic precipitator, there are still problems such as insufficient space for the transformation of the existing electrostatic precipitator
In addition, existing electrocoagulation techniques are not effective in controlling condensable PM 2.5 , volatile heavy metals and semi-volatile organic pollutants are not obvious

Method used

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  • Method for removing fine particles and heavy metals in coal fume

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] The present invention utilizes the experimental four electric field electrostatic precipitator of laboratory to carry out experiment. The length and width of the four dust collection plates in the electric area of ​​the electrostatic precipitator are both 0.3m, and the total area of ​​the dust collection plates is 0.72m 2 , The distance between dust collectors is 0.2m. The effective space of the bonding area between the electric fields is about 0.012m 3 . The discharge electrode structure of the spray gun is single-needle, the power supply voltage is 0-80kV, the charging current is 0-80 microampere, and the adsorbent injection rate is 0-1kg / h (continuously adjustable). The adsorbent is charged and sprayed into the area between two adjacent electric fields by using a spray gun.

[0035] The dust concentration in the simulated coal-fired flue gas is 2000mg / m 3 , the total mercury content is about 20μg / m 3 , SO 3 Concentration is 20ppm, flue gas flow rate is 200m 3 ...

Embodiment 2

[0038] The device and method are the same as in Example 1, except that magnesium oxide powder with a particle size of 40-60 μm is added in a proportion of 30 wt % while spraying on the iron-titanium adsorbent. The results show that after the adsorbent is mixed with magnesium oxide, the concentration of soot in the outlet flue gas can be reduced to 30mg / m 3 around, the removal rate of mercury remains basically the same, but the SO 3 The removal efficiency can be increased to about 70%. It can be seen that the mixed use of adsorbent and magnesium oxide can significantly improve the removal efficiency of various pollutants.

Embodiment 3

[0040] The device and method are the same as examples 1 and 2, and the experiment is carried out mainly on the recovery and separation of the adsorbent. A standard cyclone separator with a diameter of 250mm is used to process the mixture of adsorbent and fine particles collected by the electrostatic precipitator. According to the analysis of the results, after the adsorbent is separated by two high-speed cyclones, the fine particles attached to the surface can basically be stripped off and collected separately from the adsorbent through inertial separation, and the adsorbent can be reused.

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Abstract

The invention relates to a method for removing fine particles and heavy metals in coal fume. The method is an electric precipitator coupling charging absorbing agglomeration technology. The method comprises the steps of: pre-charging (positive charge) on an adsorbent by a charging spray gun, and spraying the adsorbent to an area between two adjacent electric fields of the electric precipitator; by a Coulomb agglomeration action between a positively charged absorbent particle and a fine particle which is negatively charged by last electric field and is not captured, and an absorption action of the charged absorbent, capturing a plurality of pollutants including fine particles, heavy metals and condensable substances, onto the absorbent to form larger particles; and efficiently capturing the larger particles by the electric field at the back of the electric precipitator, so as to achieve the purpose of synergistically removing a plurality of pollutants in smoke. Compared with prior art, the method of removing fine particles and heavy metals in coal fume has the advantages of high efficiency and low cost and the like.

Description

technical field [0001] The invention belongs to the field of environmental protection and relates to a discharge control technology for various pollutants such as coal-fired flue gas fine particles, heavy metals and condensable substances. In particular, it relates to a method for removing fine particles and heavy metals by coupling an electrostatic precipitator with charge adsorption and condensation technology. Background technique [0002] PM 2.5 (particulate matter) refers to particulate matter in the atmosphere with an aerodynamic diameter less than or equal to 2.5 microns. Thanks to PM 2.5 Belonging to submicron fine particles, it will be inhaled into the human lungs and enter the bronchi, interfering with the gas exchange in the lungs. Scientific analysis shows that submicron dust PM entering the lungs 2.5 It cannot be excreted from the body, causing lung diseases and affecting human health. At the same time, submicron dust PM 2.5 The composition of the compound...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B03C3/01B04C9/00
Inventor 瞿赞晏乃强马永鹏潘杰徐浩淼
Owner SHANGHAI JIAO TONG UNIV
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