CN111729760A - A wet electrostatic precipitator for enhanced SO3 agglomeration and removal by stepped deep cooling phase change - Google Patents

Abstract

The invention proposes a wet electrostatic precipitator for strengthening SO ₃ agglomeration and removal by step-deep cooling and phase change. A cooling zone, a wet electrostatic precipitator, a demisting zone and an outlet end, a number of first nozzles are installed in the pre-spray zone, the first nozzles are connected to the water supply system, the first cooling zone, the second cooling zone The bottom of the water collection tank is respectively provided with a first water collection tank and a second water collection tank, and the bottoms of the first water collection tank and the second water collection tank are respectively connected with a grey water circulation system, and a spray device is arranged on the grey water circulation system. The device has a plurality of second nozzles, the first cooling zone and the second cooling zone are respectively provided with a wet electrostatic precipitator, the second nozzle is arranged on the top of the wet electrostatic precipitator, and the mist removal zone is provided with a wet electrostatic precipitator. There is a defogger. The device can improve the applicable range of the wet electrostatic precipitator to SO ₃ and can significantly reduce the emission of blue smoke plumes.

Description

A wet electrostatic precipitator for enhanced SO3 agglomeration and removal by stepped deep cooling phase change

【Technical field】

The invention relates to the technical field of electric power environmental protection, in particular to a wet electrostatic precipitator capable of strengthening the agglomeration and removal of SO ₃ by stepped deep cooling and phase change.

【Background technique】

In the process of coal combustion, a part of sulfur is directly converted into sulfur trioxide (SO ₃ ), and a part of sulfur dioxide (SO ₂ ) is oxidized by catalytic reduction under high temperature conditions, and converted into sulfur trioxide (SO ₃ ). When sulfur trioxide reaches a certain concentration, it is easy to cause environmental pollution and aggravate smog when it is discharged into the atmosphere. After the sulfur trioxide enters the wet desulfurization tower, it forms aerosols, which are discharged through the chimney and form a "blue plume", which is the main cause of "acid rain". At present, the efficiency of the removal equipment for SO ₃ is relatively low, generally only about 20%.

In conventional wet electrostatic precipitators, when the inlet SO ₃ is too high, such as more than 50mg/m ³ , it will not only reduce the SO ₃ removal efficiency, but also the space charge effect of aerosol particles will also affect the discharge of the discharge electrode, resulting in the removal of particulate matter. The emission of particulate matter is difficult to meet the standard, and a wet electrostatic precipitator with stepped deep cooling phase change to strengthen SO ₃ agglomeration and removal is proposed.

[Content of the invention]

The purpose of the present invention is to solve the problems in the prior art, and to propose a wet electrostatic precipitator for strengthening the agglomeration and removal of SO ₃ by stepped deep cooling phase change, which can improve the application range _{of the wet electrostatic precipitator to SO 3 .} When the concentration reaches 50-100mg/ ^m3 , the performance of electrostatic precipitator will not be reduced, and the emission of blue plume can be significantly reduced.

In order to achieve the above purpose, the present invention proposes a wet electrostatic precipitator for strengthening the agglomeration and removal of SO ₃ by stepped deep cooling and phase change, including an inlet end, a diversion area, a pre-spray area, a first A cooling zone, a second cooling zone, a wet electrostatic precipitator, a demisting zone and an outlet end, a number of first nozzles are installed in the pre-spray zone, the first nozzles are connected to the water supply system, and the water supply system is the first nozzle Provide lye, the bottoms of the first cooling zone and the second cooling zone are respectively provided with a first water collection tank and a second water collection tank, and the bottoms of the first water collection tank and the second water collection tank are respectively connected with the grey water circulation system , the grey water circulation system is provided with a spray device, the spray device is provided with a plurality of second nozzles, the first cooling zone and the second cooling zone are respectively provided with wet electrostatic precipitators, the second cooling zone The nozzle is arranged on the top of the wet electrostatic precipitator, and a mist eliminator is arranged in the mist elimination area.

Preferably, the first water collection tank and the second water collection tank are respectively connected with two grey water circulation systems, and each grey water circulation system includes a circulation pump, a water treatment device, a partition heat exchanger, a circulation liquid supply pipe and a spray The water treatment device has an alkali replenishing port, and a PH meter is also connected to the water treatment device. The water inlet end of the water treatment device is connected to the first water collecting tank and the second water collecting tank. The liquid outlet end is connected with the liquid inlet end of the circulating pump, the liquid outlet end of the circulating pump is connected with the circulating liquid supply pipe through a partition heat exchanger, and the liquid outlet end of the circulating liquid supply pipe is connected with the spray device .

Preferably, the water supply system includes a first liquid supply pump, a lye tank, and a first liquid supply pipe, the lye tank is provided with a water supply port and an alkali replenishment port, and a pH meter is also connected to the lye tank, The liquid outlet of the lye tank is connected to the liquid inlet end of the first liquid supply pump, and the liquid outlet end of the first liquid supply pump is connected to a plurality of first liquid supply pipes, and the first liquid supply pipes A plurality of first nozzles are installed thereon, and the temperature of the mist droplets sprayed by the first nozzles is lower than the temperature of the flue gas.

Preferably, the wet electrostatic precipitator is connected to a power source, the wet electrostatic precipitator has a plurality of anode plates and cathode lines, the anode plates and cathode lines are arranged in parallel with each other, and the anode plate is connected to the adjacent cathode lines An electric field channel is formed between them.

Preferably, the diversion area is in the shape of a bell mouth, and the cross-sectional area of the diversion area gradually increases along the flue gas treatment direction. The diversion area is provided with a number of first diversion plates arranged obliquely. A guide channel is formed between the two first guide plates, and the cross-sectional area of the guide channel increases gradually along the flue gas conveying direction.

Preferably, the defogging area is in the shape of a bell mouth, and the cross-sectional area of the defogging area gradually decreases along the flue gas treatment direction.

The beneficial effects of the present invention: the pre-spray area of the present invention can spray high-concentration lye (such as sodium hydroxide, sodium carbonate, sodium bicarbonate solution, etc.), part of the sulfur dioxide in the flue gas can be absorbed by the lye, and then the flue gas is sequentially After the first cooling zone and the second cooling zone, the agglomeration of fine particles is promoted, and the temperature of the spray slurry can be reduced by the partition heat exchanger, thereby reducing the temperature of the spray water, and promoting the stepwise reduction of the smoke temperature in the wet electric field, thereby effectively improving the concentration of condensable particles. It can filter the condensation effect of fine particles or sulfuric acid aerosol as condensation nuclei, and promote the efficient agglomeration of fine particles through turbulent drag force, temperature gradient force, electric field force, etc. Particles with a certain cutting particle size are efficiently removed together with the droplets to effectively avoid their escape. The PM1 agglomeration efficiency of the device can reach more than 50%, the removal efficiency of PM2.5 can reach more than 80%, and the removal of condensable particulate matter (including SO ₃ ) can reach more than 70%, which effectively improves the wet electrostatic precipitator's ability to remove SO ₃ When the concentration of SO ₃ reaches 50-100mg/m ³ , the performance of electrostatic precipitator will not decrease. The device can be used for waste gas treatment in coal-fired power plants, chemical industry, metallurgy, cement and other industries, and can significantly reduce blue plume emissions.

The features and advantages of the present invention will be described in detail through embodiments in conjunction with the accompanying drawings.

【Description of drawings】

Fig. 1 is a schematic diagram of the internal structure of a wet electrostatic precipitator of the present invention for strengthening SO ₃ agglomeration and removal by step-deep cooling phase change.

【Detailed ways】

Referring to Fig. 1, a wet electrostatic precipitator of the present invention for strengthening the agglomeration and removal of SO ₃ by step-depth cooling and phase change comprises an inlet end 1, a diversion zone 2, a pre-spray zone 3, a first cooling zone arranged in sequence along the flue gas treatment direction Zone 4, second cooling zone 5, wet electrostatic precipitator 6, demisting zone 7 and outlet end 8, a number of first nozzles 34 are installed in the pre-spray zone 3, and the first nozzles 34 are connected to the water supply system , the water supply system provides lye for the first nozzle 34, the bottoms of the first cooling zone 4 and the second cooling zone 5 are respectively provided with a first water collection tank 40 and a second water collection tank 50, the first water collection tank 40, The bottoms of the second sump 50 are respectively connected with the grey water circulation system, and the grey water circulation system is provided with a spray device, and the spray device has a plurality of second nozzles 45, the first cooling zone 4, the first cooling zone A wet electrostatic precipitator 6 is respectively provided in the second cooling zone 5 , the second nozzle 45 is arranged on the top of the wet electrostatic precipitator 6 , and a mist eliminator is arranged in the demisting zone 7 .

Further, the first water collection tank 40 and the second water collection tank 50 are respectively connected with two grey water circulation systems, and each grey water circulation system includes a circulation pump 41, a water treatment device 42, a partition heat exchanger 43, a circulating supply The liquid pipe 44 and the spray device, the water treatment device 42 is provided with an alkali replenishing port, and the water treatment device 42 is also connected with a PH meter for adding alkali to adjust the pH value. The first water collecting tank 40 and the second water collecting tank 50 are connected, the liquid outlet end of the water treatment device 42 is connected with the liquid inlet end of the circulating pump 41, and the liquid outlet end of the circulating pump 41 and the circulating liquid supply pipe 44 pass through. The partition heat exchanger 43 is connected, and the liquid outlet end of the circulating liquid supply pipe 44 is connected with the spraying device to realize the recycling of the slurry.

Further, the water supply system includes a first liquid supply pump 31, a lye tank 32, and a first liquid supply pipe 33. The lye tank 32 has a water supply port and an alkali replenishment port, and the lye tank 32 also has a A PH meter is connected, the liquid outlet of the lye tank 32 is connected to the liquid inlet end of the first liquid supply pump 31, and the liquid outlet end of the first liquid supply pump 31 is connected to a plurality of first liquid supply pipes 33. connected, a plurality of first nozzles 34 are installed on the first liquid supply pipe 33, and the temperature of the mist droplets sprayed by the first nozzles 34 is lower than the temperature of the flue gas.

Further, the wet electrostatic precipitator 6 is connected to a power source 60, and the wet electrostatic precipitator 6 has a plurality of anode plates 61 and cathode lines 62, the anode plates 61 and cathode lines 62 are arranged parallel to each other, and the anode plates 61 and cathode lines 62 are arranged in parallel to each other. An electric field channel is formed between the plate 61 and the adjacent cathode lines 62 .

Further, the guide area 2 is in the shape of a bell mouth, and the cross-sectional area of the guide area 2 is gradually increased along the flue gas treatment direction. The guide area 2 is provided with a number of first guide plates 21 that are arranged obliquely. , a guide channel is formed between two adjacent first guide plates 21 , and the cross-sectional area of the guide channel gradually increases along the flue gas conveying direction.

Further, the defogging area 7 is in the shape of a bell mouth, and the cross-sectional area of the defogging area 7 decreases gradually along the flue gas treatment direction.

The working process of the present invention:

The working process of the wet electrostatic precipitator for strengthening the agglomeration and removal of SO ₃ by step-depth cooling and phase change of the present invention: the flue gas enters from the inlet end 1, is diverted from the diversion zone 2 and enters the pre-spray zone 3, and the first nozzle 34 It can spray high-concentration lye (such as sodium hydroxide, sodium carbonate, sodium bicarbonate solution, etc.), part of the sulfur dioxide in the flue gas can be absorbed by the lye, and then the flue gas passes through the first cooling zone 4 and the second cooling zone in turn 5. Promote the agglomeration of fine particles, and the temperature of the spray slurry can be reduced by the partition heat exchanger 43, thereby reducing the temperature of the spray water, and promoting the stepwise reduction of the smoke temperature in the wet electric field, thereby effectively increasing the condensable particles and filtering fine particles or sulfuric acid aerosols It is the condensation effect of condensation nuclei, and promotes the efficient agglomeration of fine particles through turbulent drag force, temperature gradient force, electric field force, etc. Finally, the wet electrostatic precipitator 6 is used for high-efficiency dust removal. The droplets are efficiently removed together to effectively avoid their escape, and the treated flue gas is discharged through the outlet end 8 .

The device can be used for waste gas treatment in coal-fired power plants, chemical industry, metallurgy, cement and other industries, and can significantly reduce blue plume emissions. The agglomeration efficiency of PM1 can reach more than 50%, the removal efficiency of PM2.5 can reach more than 80%, and the removal of condensable particulate matter (including SO ₃ ) can reach more than 70%, which effectively improves the application of wet electrostatic precipitator to SO ₃ When the concentration of SO ₃ reaches 50～100mg/m ³ , the electrostatic precipitator performance will not decrease.

The above-mentioned embodiments are illustrative of the present invention, not limitations of the present invention, and any scheme after simple transformation of the present invention belongs to the protection scope of the present invention.

Claims (6)

1. the wet electrostatic precipitator of step _- wise deep cooling phase change strengthening SO3 agglomeration removal, it is characterized in that: comprise the inlet end (1), the diversion zone (2), the pre-spray zone that are arranged successively along the flue gas treatment direction (3), the first cooling zone (4), the second cooling zone (5), the wet electrostatic precipitator (6), the demisting zone (7) and the outlet end (8), in the pre-spray zone (3) A number of first nozzles (34) are installed, the first nozzles (34) are connected to a water supply system, and the water supply system provides the first nozzles (34) with lye, the first cooling zone (4), the second cooling The bottom of the area (5) is respectively provided with a first water collection tank (40) and a second water collection tank (50), and the bottoms of the first water collection tank (40) and the second water collection tank (50) are respectively connected with the grey water circulation system. connected, the grey water circulation system is provided with a spray device, the spray device is provided with a plurality of second nozzles (45), and the first cooling zone (4) and the second cooling zone (5) are respectively provided with There is a wet electrostatic precipitator (6), the second nozzle (45) is arranged on the top of the wet electrostatic precipitator (6), and a mist eliminator is provided in the demisting zone (7). 2. The wet electrostatic precipitator for step-deep cooling and phase change strengthening SO3 agglomeration and removal as claimed in claim ₁ , characterized in that: the first water collecting tank (40) and the second water collecting tank (50) are respectively Connected with two grey water circulation systems, each grey water circulation system includes a circulating pump (41), a water treatment device (42), a partition heat exchanger (43), a circulating liquid supply pipe (44) and a spray device, so The water treatment device (42) is provided with an alkali replenishing port, a pH meter is also connected to the water treatment device (42), and the water inlet end of the water treatment device (42) is connected to the first water collecting tank (40) and the second collecting tank (40). The water tank (50) is connected, the liquid outlet end of the water treatment device (42) is connected with the liquid inlet end of the circulating pump (41), and the liquid outlet end of the circulating pump (41) is connected with the circulating liquid supply pipe (44) They are connected through a partition heat exchanger (43), and the liquid outlet end of the circulating liquid supply pipe (44) is connected with a spray device. 3. the wet electrostatic precipitator of a kind of step-deep cooling phase change strengthening SO3 agglomeration removal as claimed in claim ₁ , is characterized in that: described water supply system comprises the first liquid supply pump (31), lye tank ( 32), the first liquid supply pipe (33), the lye tank (32) is provided with a water supply port and an alkali replenishing port, the lye tank (32) is also connected with a pH meter, and the lye tank (32) is provided with a pH meter. The liquid outlet of 32) is connected with the liquid inlet end of the first liquid supply pump (31), and the liquid outlet end of the first liquid supply pump (31) is connected with a plurality of first liquid supply pipes (33), so A plurality of first nozzles (34) are installed on the first liquid supply pipe (33), and the temperature of the mist droplets sprayed by the first nozzles (34) is lower than the temperature of the flue gas. 4. The wet electrostatic precipitator for a step-deep cooling phase change strengthening SO3 agglomeration removal according to any one of claims 1 to ₃ , characterized in that: the wet electrostatic precipitator (6) and the power supply ( 60) connected, the wet electrostatic precipitator (6) has a plurality of anode plates (61) and cathode lines (62), the anode plates (61) and cathode lines (62) are arranged in parallel with each other, the anode plates An electric field channel is formed between (61) and adjacent cathode lines (62). 5. The wet electrostatic precipitator of step-deep cooling phase change strengthening SO3 agglomeration and removal as claimed in claim ₁ , characterized in that: the diversion area (2) is in the shape of a bell mouth, along the flue gas treatment direction The cross-sectional area of the guide area (2) is gradually increased, and a plurality of first guide plates (21) arranged at an inclination are arranged in the guide area (2), and two adjacent first guide plates (21) are arranged in the guide area (2). A diversion channel is formed between ), and the cross-sectional area of the diversion channel increases gradually along the flue gas conveying direction. 6. The wet electrostatic precipitator for step-deep cooling and phase change strengthening SO3 agglomeration and removal as claimed in claim ₁ , characterized in that: the defogging zone (7) is in the shape of a bell mouth, along the flue gas treatment direction The cross-sectional area of the defogging zone (7) gradually decreases.

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