CN103495504A - Multi-level charging coagulation device for removing fine dust and mercury - Google Patents

Abstract

The invention discloses a multi-stage charged coagulation device for efficiently removing fine dust and mercury, which comprises a shell, and the front part of the shell is provided with a charging area, the middle part is provided with a coagulation area, and the rear part is provided with a recharging area. area; this device is suitable for efficiency improvement of existing electrostatic precipitators. By setting up a recharge area, the collection efficiency of fine dust can be further improved; at the same time, elemental mercury can be converted into oxidized mercury after multiple oxidations, which is easier It is adsorbed by dust and converted into particulate mercury, so as to realize the efficient removal of mercury in subsequent equipment. The removal efficiency of this device for fine dust and mercury is as high as 99.8% and 68% respectively; the device has a simple structure, no need to modify the dust collector during use, it can be constructed and repaired offline, the maintenance workload is small, and the work is stable and reliable.

Description

A multi-stage charged coagulation device for removing fine dust and mercury

technical field

The invention relates to a dust removal device, in particular to a multi-stage charged coagulation device for removing fine dust and mercury.

Background technique

Fine dust and mercury are the main pollutants contained in the flue gas of thermal power plants. Fine dust can be deposited in the alveoli of the human body, leading to lung diseases such as silicosis; mercury is a chemical substance with severe physiological toxicity, which can enter the human body through the respiratory tract, esophagus and skin. Excessive inhalation of mercury by the human body can also cause mercury poisoning.

China has implemented the "Emission Standards of Air Pollutants for Thermal Power Plants" GB13223-2011 since 2011, and the emission standards of particulate matter have been raised from 50mg/m ³ to 20-30mg/m ^{3 .} , it is clear that the mercury content in the atmosphere should not exceed 0.03mg/m ³ . Existing high-efficiency dust collectors, such as electrostatic precipitators, bag filters, and cyclone dust collectors, are the most widely used. Although the total dust emission concentration is not high, due to the limitation of the mechanism, the collection efficiency for fine particles of about 1 μm is low. With the increasing environmental emission standards, using less investment and operating costs to improve the collection efficiency of fine dust has become an effective means of improving the efficiency of existing high-efficiency dust collectors.

Mercury in flue gas includes elemental mercury (Hg ⁰ ), oxidized mercury (Hg ²⁺ ) and particulate mercury (Hg ^p ), and their removal difficulty decreases in turn. Studies have shown that mercury in flue gas mainly exists in the form of elemental mercury and oxidized mercury, and the particulate mercury is less than 20%. Particulate mercury can be removed by a dust collector, and oxidized mercury can be effectively removed in a wet removal system; elemental mercury is gaseous and has poor hydrophilicity, so traditional dust collectors and wet detergent systems have lower removal efficiencies. very low. Therefore, with the increasingly stringent mercury emission standards, it is imperative to use appropriate devices to achieve efficient removal.

Electrostatic precipitators are widely used due to their high efficiency, stability, reliability, and easy maintenance. However, in recent years, with the increasing environmental protection standards, it is urgent to transform the electrostatic precipitator. In order to cope with the new situation, conventional measures such as changing the electric bag, increasing equipment specifications, and increasing the number of electric fields are usually adopted for the transformation of the electrostatic precipitator. However, due to its own defects, the bag filter cannot completely replace the electrostatic precipitator. Retrofitting measures are usually affected by unfavorable factors such as high retrofit costs, long construction period, and site limitations, and are often difficult to implement.

The patent document with the publication number CN202006137U discloses a fine dust electrocoagulation device. The device is connected to the flue, including: a shell, one end is the flue gas inlet, and the other end is the flue gas outlet; several pairs of discharge electrodes are fixed on the shell In the body, each pair of discharge electrodes includes positive and negative discharge electrodes, and several pairs of discharge electrodes are arranged in parallel with the direction of flue gas in and out in each pair of positive and negative procedures in the casing to form an electrode group; several grounding plates are respectively fixed on the casing. Between every two electrodes in the electrode group in the body; several pairs of condensed electrodes are fixedly distributed in the casing near the smoke outlet, and are made of conductive materials.

After the fine dust is agglomerated by the agglomeration device disclosed in the above-mentioned patent documents, it needs to pass through the electrostatic precipitator to remove coarse particles. Since the dust collecting plate of the general electrostatic precipitator is an anode plate, some positively charged particles are too late in the agglomeration area. Agglomerates with negatively charged particles, causing positively charged particles to be difficult to reach the dust collecting plate in the electrostatic precipitator and discharged directly, which is not conducive to dust removal and mercury removal

Contents of the invention

The invention provides a multi-stage charged coagulation device for removing fine dust and mercury. By setting a recharging zone, the collection efficiency of fine dust is further improved; at the same time, the elemental mercury is converted into an oxidized state after multiple oxidations. Mercury is more likely to be adsorbed by dust and converted into particulate mercury, so as to achieve efficient removal of mercury in subsequent equipment.

The invention discloses a multi-stage charged coagulation device for removing fine dust and mercury, which comprises a shell, the front part of the shell is provided with a charging area, the middle part is provided with a coagulation area, and the rear part is provided with a recharging area ;

Several pairs of discharge electrodes are fixed in the charging area, and each pair of discharge electrodes includes a positive discharge electrode and a first negative discharge electrode. Several pairs of discharge electrodes are arranged in the casing with each pair of positive discharge electrodes and the first negative discharge electrode along the length of the casing. The directions are arranged in parallel to form an electrode group. Each first negative discharge electrode is connected to a negative high-voltage power supply, and each positive discharge electrode is connected to a positive high-voltage power supply; a first discharge electrode is arranged in parallel between two adjacent positive discharge electrodes and the first negative discharge electrode. Grounding plates, all the first grounding plates are connected together and connected to the grounding grid;

The coagulation area is provided with several coagulation electrodes placed vertically at the bottom of the casing;

In the recharging area, a group of second negative discharge electrodes placed in parallel are fixed along the length direction of the shell, and each second negative discharge electrode is connected to a negative high voltage power supply; between two adjacent second negative discharge electrodes, there are parallel A second ground plane, all the second ground planes are connected together and connected to the ground grid.

Preferably, there are at least two pairs of discharge electrodes in the charging area, and the high-voltage power supply is provided with two sets of transformers and two sets of control cabinets.

An insulating material is provided between each positive discharge electrode and the first negative discharge electrode in the charging area and the junction of the casing.

The condensing electrode can be cylindrical, elliptical cylindrical, grooved, narrow or angled, and preferably, the condensing electrode is cylindrical, and the use of a cylindrical condensing electrode can reduce resistance and improve coagulation and mixing. The effect, thereby improving the efficiency of dust removal and mercury removal.

Preferably, the diameter of the cylindrical condensing electrodes is equal to the distance between the adjacent positive plate in the charging area and the first negative plate, and the number of the condensing electrodes is at least twice the number of the discharging electrodes. The material of the condensation electrode is a non-metal wear-resistant material.

As preferably, the distance between adjacent plates in the recharging zone is equal to the distance between the adjacent positive discharge electrodes and the first negative discharge electrode in the charging zone; the length of the plates in the recharging zone is the length of the pole plates in the charging zone 1/20~1/2 of that. Considering the aggregation efficiency and manufacturing cost comprehensively, the length of the electrode plate in the recharging region is preferably within the above range.

Preferably, an insulating material is provided between each second negative discharge electrode in the recharging area and the bottom plate, and a set of transformers and a set of control cabinets are provided for the high-voltage power supply.

Preferably, the voltage of the high-voltage power supply in the recharging zone is 40-300KV; more preferably 130-300KV. High voltage is beneficial to the removal of mercury, but it is more difficult to manufacture a power supply with too high voltage.

Preferably, the shell is made of plain carbon steel.

The working principle of the multi-stage charged coagulation device for removing fine dust and mercury according to the present invention is as follows: the fine dust first passes through the charging area of the multi-stage charged coagulation device, and is charged negatively and positively in the charging area respectively, The uncondensed fine dust or condensed large particle dust is negatively charged in the recharging zone, which cooperates with the anode dust collecting plate in the subsequent electrostatic precipitator. Since some particles are positively charged in the charging area, they cannot condense with negatively charged particles in time, and entering the subsequent electrostatic precipitator is not good for dust removal. Therefore, carrying negative charges in the recharging area can increase the dust removal efficiency of electrostatic precipitator and improve the dust removal efficiency of fine dust again. capture efficiency. At the same time, the multi-stage charged coagulation device oxidizes elemental mercury to oxidized mercury multiple times, which is more easily absorbed by dust and converted into particulate mercury, so as to achieve efficient removal of mercury in subsequent equipment.

The beneficial effect of this device:

The device is especially suitable for improving the efficiency of the existing electrostatic precipitator to improve the removal efficiency of fine dust and mercury. Its electrocoagulation device can be installed on the flue before the inlet of the dust collector. After the flue gas passes through the device, the fine particles can condense and increase, and the fine dust in the recharging area will be negatively charged, and it will be collected with the anode in the subsequent electrostatic precipitator. The combination of these plates increases the dust removal efficiency of the electrostatic precipitator, and improves the collection efficiency of fine dust again; at the same time, the elemental mercury is oxidized to oxidized mercury for many times, which is easier to be adsorbed by fly ash and converted into particulate mercury, thereby improving the follow-up equipment. The removal efficiency of fine dust and mercury. It can improve the removal of PM2.5 fine particles and mercury by the existing dust collector, and effectively improve the ambient air quality. The structure of the device is simple, there is no need to modify the dust collector during use, it can be built and repaired offline, the maintenance workload is small, and the work is stable and reliable.

Description of drawings

Fig. 1 is the structural representation of device of the present invention;

Figure 2 is a top view of the device of the present invention.

Detailed ways

The specific implementation of the method will be described in detail below in conjunction with the accompanying drawings of the embodiments.

Example 1

Referring to Figures 1-2, the device of the present invention includes a housing 1, in which a charging zone is provided at the front, a coagulation zone is provided at the middle, and a recharging zone is provided at the rear.

Six pairs of discharge electrodes are fixed in the charging area, and each pair of discharge electrodes includes the first negative discharge electrode 2 and the positive discharge electrode 4, and the six pairs of discharge electrodes are arranged in the housing 1 along the sides of each pair of positive and first negative discharge electrodes. The length direction of the shells is arranged in parallel to form an electrode group, each first negative discharge electrode 2 is connected to a negative high voltage power supply (not shown), and each positive discharge electrode 4 is connected to a positive high voltage power supply (not shown). Polytetrafluoroethylene is used as insulating material between each positive and first negative discharge electrode and the junction of the shell. The discharge electrode is composed of zigzag lines. A first grounding plate 3 is arranged in parallel between two adjacent positive and first negative discharge electrodes, and all the first grounding plates 3 are connected together and connected to a grounding grid (not shown).

The condensation area is provided with a cylindrical condensation electrode 5 placed vertically on the bottom of the casing, and its diameter is equal to the distance between the adjacent positive and first negative plates of the charging area. The condensation electrodes are arranged in three rows, and there are six condensation electrodes in each row. The positive discharge electrodes in the area are on the same straight line, and the center of the third row of cylindrical condensation electrodes is on the same straight line as the negative discharge electrodes in the charging area. The cylindrical condensation electrodes are made of ceramics.

In the recharging area, six pairs of second negative discharge electrodes placed in parallel are fixed along the length direction of the shell, the distance between adjacent plates is equal to the distance between the adjacent positive and first negative plates in the charging area, and the length of the plates is 1/5 of the length of the electrode plate. Each second negative discharge electrode 6 is connected to a negative high voltage power supply (not shown), and polytetrafluoroethylene is used as an insulating material between each second negative discharge electrode 6 and the casing. A second grounding plate 7 is arranged in parallel between two adjacent second negative discharge electrodes, and all the second grounding plates are connected together and connected to a grounding grid (not shown).

In this multi-stage charged coagulation device for highly efficient removal of fine dust and mercury:

(1) The wind speed of the electric field in the coalescer is 5m/s;

(2) The power supply mode of the charging area is a positive and negative DC high-voltage power supply with adjustable frequency, which are respectively connected to the positive and negative discharge electrodes, and the power supply voltage is 80kV. The power supply mode of the recharging area is a frequency-adjustable negative DC high-voltage power supply, and the power supply voltage is 200kV.

Example 2

In this embodiment, the power supply voltage in the recharging area is 80kV, and the same device as in Embodiment 1 is used.

comparative example

In this comparative example, the same apparatus as in Example 1 was used except for the recharging zone.

Application example 1:

The flue gas inlet contains 45 μg/m ³ mercury and 11 g/m ³ smoke dust, and the flow rate is 100000 m ³ /h. After the multi-stage charged coagulation device and conventional electrostatic precipitator in Example 1, the concentrations of mercury and smoke dust are respectively reduced to 13μg/m ³ and 20mg/m ³ , the removal efficiencies of mercury and soot are 71.1% and 99.8% respectively;

After the multi-stage charged coagulation device of Example 2 and the conventional electrostatic precipitator, the concentrations of mercury and soot were reduced to 15 μg/m ³ and 28 mg/m ³ respectively, and the removal efficiencies of mercury and soot were 66.7% and 99.7% respectively;

After the comparative single-stage charged coagulation device and conventional electrostatic precipitator, the concentrations of mercury and soot were reduced to 26μg/m ³ and 80mg/m ³ respectively, and the removal efficiencies of mercury and soot were 42.2% and 99.3% respectively.

Application example 2:

The flue gas inlet contains 82μg/m ³ mercury and 9g/m ³ smoke dust, and the flow rate is 500000m ³ /h. After the multi-stage charged coagulation device and conventional electrostatic precipitator in Example 1, the concentrations of mercury and smoke dust are respectively reduced to 26μg/m ³ and 15mg/m ³ , the removal efficiencies of mercury and soot are 68.3% and 99.8% respectively;

After the multi-stage charged coagulation device of Example 2 and the conventional electrostatic precipitator, the concentrations of mercury and soot were reduced to 29 μg/m ³ and 23 mg/m ³ respectively, and the removal efficiencies of mercury and soot were 64.6% and 99.7% respectively;

After the comparative single-stage charged coagulation device and conventional electrostatic precipitator, the concentrations of mercury and dust were reduced to 51 μg/m ³ and 70 mg/m ³ respectively, and the removal efficiencies of mercury and dust were 37.8% and 99.2%, respectively.

The above is only a preferred specific implementation of this method, but the protection scope of this method is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of this method. Therefore, the protection scope of the method should be based on the protection scope of the claims.

Claims (10)

1. a multi-lever electric coacervation device that removes fine dust and mercury, comprise housing, it is characterized in that, in described housing, front portion is provided with charging area, and middle part is provided with condensation region, and rear portion is provided with charging area again;

In described charging area, be fixed with several to sparking electrode, every pair of sparking electrode comprises positive sparking electrode and the first negative sparking electrode, several to sparking electrode in housing often aligning sparking electrode, the first negative sparking electrode is arranged in parallel along the shell length direction, form the electrode group, each first negative sparking electrode connects negative high voltage power source, and each positive sparking electrode connects the positive high voltage power supply; Parallelly between adjacent two positive sparking electrodes and the first negative sparking electrode be provided with first earth plate, all the first earth plates connect, and are connected with grounded screen;

Be provided with the cohesion electrode that place several vertical shell bottom in described condensation region;

In described charging area again, be fixed with the second negative sparking electrode of the parallel placement of array along the shell length direction, each second negative sparking electrode connects negative high voltage power source; Parallelly between adjacent two the second negative sparking electrodes be provided with second earth plate, all the second earth plates connect, and are connected with grounded screen.

2. the multi-lever electric coacervation device that removes fine dust and mercury as claimed in claim 1, is characterized in that, several in described charging area sparking electrode be at least 2 pairs, and high voltage source is provided with two cover transformers, and two overlap switch boards.

3. the multi-lever electric coacervation device that efficiently removes fine dust and mercury as claimed in claim 2, is characterized in that, in described charging area, between each positive sparking electrode and the first negative sparking electrode and base plate, is provided with insulating materials.

4. the multi-lever electric coacervation device that removes fine dust and mercury as claimed in claim 1, it is characterized in that, described cohesion electrode is cylindrical, and its diameter equals charging area adjacent positive plate and the first negative plate spacing, and the quantity of described cohesion electrode is at least 2 times of sparking electrode quantity.

5. the multi-lever electric coacervation device that efficiently removes fine dust and mercury as claimed in claim 4, is characterized in that, described cohesion electrode material is nonmetallic wear-resistant material.

6. the multi-lever electric coacervation device that efficiently removes fine dust and mercury as claimed in claim 1, is characterized in that, the described adjacent plate of charging area again spacing equals the polar plate spacing of the adjacent positive sparking electrode of charging area and the first negative sparking electrode; The described pole plate of charging area again length is 1/20～1/2 of charging area pole plate length.

7. the multi-lever electric coacervation device that efficiently removes fine dust and mercury as claimed in claim 6, is characterized in that, between each second negative sparking electrode of described charging area again and base plate, is provided with insulating materials, and high voltage source is provided with a set of transformer, a set of switch board.

8. the multi-lever electric coacervation device that efficiently removes fine dust and mercury as claimed in claim 7, is characterized in that, the voltage of the described inner high voltage of charging area again power supply is 40～300KV.

9. the multi-lever electric coacervation device that efficiently removes fine dust and mercury as claimed in claim 8, is characterized in that, the voltage of the described inner high voltage of charging area again power supply is 130～300KV.

10. the multi-lever electric coacervation device that efficiently removes fine dust and mercury as claimed in claim 1, is characterized in that, described shell material is straight carbon steel.

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