A fine particle trapping system of combined rotational disturbance and flue gas condensation

Abstract

The application discloses a kind of fine particle trapping systems of rotary disturbance combined flue gas condensation, it is related to waste heat recovery and dust removal field, it is characterized in that, including wet limestone-gypsum flue gas desulfurization system, cyclone air device, first stage heat exchanger, rotary fan, second stage heat exchanger and net demister by flue gas pipeline sequentially connected, first stage heat exchanger, second stage heat exchanger are connected with heat pump.The application combines the effect of turbulent flow disturbance and flue gas condensation, on the one hand, through the mode of flue gas condensation, the waste heat and moisture in flue gas are recovered, on the other hand, by adding cyclone equipment, the effective trapping and removal of fine particles are realized.

Description

Technical Field

[0001] This invention relates to the field of waste heat recovery and dust removal, and in particular to a fine particle capture system that combines rotary disturbance with flue gas condensation. Background Technology

[0002] Fine particulate matter (PM2.5) emissions from coal combustion and motor vehicles cause serious air pollution and health problems. However, traditional dust collectors, such as cyclone separators, Venturi scrubbers, electrostatic precipitators, and filters, are difficult and expensive to remove fine particles. This is because these systems remove particulate matter from flue gas based on diffusion, inertial impaction, and sedimentation methods; however, fine particles of 0.1–1 μm are too large to be effective for Brownian diffusion and too small for inertial impaction. Therefore, pretreatment techniques can be used to scale up particles to a size of several micrometers, which can greatly simplify the separation of particles from the gas.

[0003] Condensing heat exchangers can promote the growth of particles several nanometers in size into droplets of several micrometers in size. Rotational disturbance of the gas can promote particle collision, aggregation, and growth. Therefore, those skilled in the art are dedicated to developing a fine particle capture system that combines rotational disturbance with flue gas condensation. This system recovers waste heat and moisture from the flue gas through condensation, while simultaneously achieving effective capture and removal of fine particles by adding a swirling device. Summary of the Invention

[0004] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is how to achieve effective capture and removal of fine particles in flue gas.

[0005] To achieve the above objectives, the present invention provides a fine particle capture system combining rotating disturbance and flue gas condensation, characterized in that it includes a swirling air device, a first heat exchanger, a rotary fan, and a second heat exchanger, wherein the swirling air device, the first heat exchanger, the rotary fan, and the second heat exchanger are connected in sequence.

[0006] Furthermore, it also includes a wet limestone-gypsum flue gas desulfurization system and a mesh demister. The wet limestone-gypsum flue gas desulfurization system is located at the front end of the swirling air device, and the mesh demister is located at the rear end of the second heat exchanger. The wet limestone-gypsum flue gas desulfurization system, the swirling air device, the first heat exchanger, the rotary fan, the second heat exchanger, and the mesh demister are connected in sequence through a flue gas duct.

[0007] Furthermore, the swirling air device consists of air nozzles arranged on the outside of the flue gas duct, with the air outlets of the air nozzles located inside the flue gas duct. The swirling air device sends the flue gas into the first heat exchanger in a spiral shape.

[0008] Furthermore, the swirling air device rotates the flue gas in the opposite direction to the rotation of the flue gas by the rotating fan.

[0009] Furthermore, it also includes a heat pump. The first heat exchanger further includes a first cooling medium water inlet and a first cooling medium water outlet. The second heat exchanger further includes a second cooling medium water inlet and a second cooling medium water outlet. The first cooling medium water inlet, the first cooling medium water outlet, the second cooling medium water inlet, and the second cooling medium water outlet are connected to the heat pump.

[0010] Furthermore, the pipe of the first heat exchanger has a concave groove directly below it, and a first condensate outlet is provided at the lowest point of the concave groove of the first heat exchanger. The pipe of the second heat exchanger has a concave groove directly below it, and a second condensate outlet is provided at the lowest point of the concave groove of the second heat exchanger. The first condensate outlet and the second condensate outlet are connected to the wet limestone-gypsum flue gas desulfurization system.

[0011] Furthermore, the length of the second heat exchanger is shorter than the length of the first heat exchanger.

[0012] Furthermore, the tube wall temperatures of the first and second heat exchangers are lower than the flue gas water dew point temperature.

[0013] Furthermore, a condensate film is provided on the tube wall of the first heat exchanger.

[0014] Furthermore, both the first heat exchanger and the second heat exchanger are staggered tube bundle heat exchangers, and both the first heat exchanger and the second heat exchanger are equipped with cleaning devices.

[0015] This invention combines the effects of turbulence disturbance and flue gas condensation. On the one hand, it recovers waste heat and moisture from the flue gas through flue gas condensation at the first and second heat exchangers. The collected heat can be used for urban central heating, etc. On the other hand, by adding a swirling air device and a rotating fan, the particles in the flue gas are effectively collided. During the rotation of the rotating fan, sound waves with a certain frequency and sound pressure level are generated, which enhances the collision and aggregation of condensation nuclei, thus achieving effective capture and removal of fine particles.

[0016] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a fine particle capture system for combined rotational disturbance and flue gas condensation, according to a preferred embodiment of the present invention.

[0018] Among them, 1-wet limestone-gypsum flue gas desulfurization system, 2-cyclone air device, 3-first stage heat exchanger, 4-first cooling medium water inlet, 5-first condensate outlet, 6-first cooling medium water outlet, 7-rotary fan, 8-second stage heat exchanger, 9-mesh demister, 10-heat pump, 11-second cooling medium water inlet, 12-second condensate outlet, 13-second cooling medium water outlet. Detailed Implementation

[0019] The preferred embodiments of the present invention are described below with reference to the accompanying drawings to make the technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0020] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0021] like Figure 1 As shown, a fine particle capture system combining rotational disturbance and flue gas condensation includes a wet limestone-gypsum flue gas desulfurization system 1, a swirling air device 2, a first-stage heat exchanger 3, a rotary fan 7, a second-stage heat exchanger 8, and a mesh demister 9, connected sequentially through a flue gas duct. The swirling air device 2 consists of air nozzles arranged on the outside of the flue gas duct, with the outlets of the air nozzles located inside the flue gas duct. The swirling air device sends the flue gas into the first-stage heat exchanger 3 in a spiral shape. The fine particles in the flue gas undergo rotational disturbance in the swirling air device 2. Larger particles are captured by the first-stage heat exchanger 3, while fine particles nucleate under the condensation effect of the first-stage heat exchanger 3. The airflow in the opposite direction emitted by the rotary fan 7 causes the particles to collide and agglomerate, and are captured by the second-stage heat exchanger 8. Finally, the remaining moisture in the flue gas is captured by the mesh demister 9.

[0022] The wet limestone-gypsum flue gas desulfurization system 1 can achieve self-circulation of moisture in the flue gas. During the desulfurization process, the heat of the flue gas is absorbed by some of the moisture in the slurry and turned into steam. The steam enters the pipeline with the flue gas, and under the action of heat exchanger condensation, it turns into liquid water, which is then collected again by the pipeline and transported to the water pool of the desulfurization system.

[0023] Both the first heat exchanger 3 and the second heat exchanger 8 are staggered tube bundle heat exchangers. Both are equipped with cleaning devices that clean the dust from the tube bundles at regular intervals. Because the cooling intensity of the second stage is lower, the length of the second heat exchanger 8 is shorter than that of the first heat exchanger 3. The flue gas duct directly below the first and second heat exchangers 3 is a concave groove. A first condensate outlet 5 is located at the lowest end of the concave groove in the first heat exchanger 3, and a second condensate outlet 12 is located at the lowest end of the concave groove in the second heat exchanger 8. This facilitates the collection and circulation of condensate, which is then used as makeup water for the wet limestone-gypsum flue gas desulfurization system 1. The first cooling medium water outlet 6 of the first heat exchanger 3 and the second cooling medium water outlet 13 of the second heat exchanger 8 are connected to the heat pump 10. The collected heat can be used for urban central heating. The medium water cooled by the heat pump 10 enters the first cooling medium water inlet 4 of the first heat exchanger 3 and the second cooling medium water inlet 11 of the second heat exchanger 8 for recycling.

[0024] After passing through the wet limestone-gypsum flue gas desulfurization system 1, the flue gas, carrying a certain amount of moisture and residual fine particles, passes through the swirling air device 2. Under the action of swirling flow, the flue gas and fine particles undergo swirling disturbance. The flue gas undergoes heat exchange in the first heat exchanger 3. Both the first heat exchanger 3 and the second heat exchanger 8 can reduce the temperature of the flue gas to below the dew point temperature. Since the tube wall temperature is lower than the dew point temperature of the flue gas water, a supersaturated zone of water vapor is formed near the heat exchanger tube wall. In this zone, water vapor condenses on the heat exchanger tube wall and on the particles. At this time, the diffusion and thermophoresis effects generated by the water vapor concentration gradient and the flue gas temperature gradient near the tube wall of the first heat exchanger 3 cause the fine particles to move towards the tube wall of the first heat exchanger 3. At the same time, the swirling disturbance of the flue gas accelerates the collision between the fine particles and the tube wall. A highly adhesive condensate film is provided on the tube wall of the first heat exchanger 3 to prevent the particles from rebounding, thus achieving the capture and removal of some fine particles.

[0025] The remaining fine particles, under the action of heterogeneous condensation, condense into nuclei of small droplets. These nuclei, along with the flue gas, pass through the first heat exchanger 3 and enter the swirling disturbance zone of the rotary fan 7. The rotary fan 7 rotates the flue gas in the opposite direction to that of the swirling air device 2. Due to the change in the direction of the swirling disturbance, the particles in the flue gas can collide effectively. Furthermore, during the rotation of the rotary fan 7, sound waves of a certain frequency and sound pressure level are generated, which enhances the collision and aggregation of condensation nuclei, thus promoting the agglomeration of particles in the flue gas.

[0026] The agglomerated particles enter the second heat exchanger 8, where the size of the agglomerates and nucleated particles is further increased by the condensation of water vapor, which strengthens the inertial impact with the tube wall of the second heat exchanger 8, thus achieving further removal of fine particles. The agglomerates and nucleated particles that have increased in size are more easily captured by the wire mesh demister 9.

[0027] When flue gas passes through the fine particulate capture system of rotating disturbance combined with flue gas condensation provided by the present invention, the process of waste heat recovery, moisture recovery and fine particulate capture in the flue gas includes the following steps:

[0028] Step 1: After the flue gas passes through the wet limestone-gypsum flue gas desulfurization system 1, it carries a certain amount of moisture and residual fine particles through the swirling air device 2. Under the action of swirling, the flue gas and fine particles are disturbed by swirling.

[0029] Step 2: The swirling flue gas undergoes heat exchange at the first heat exchanger (section 3). Since the tube wall temperature is lower than the flue gas dew point temperature, a supersaturated zone of water vapor forms near the tube wall. Within this zone, water vapor condenses on both the tube wall and the particles. The diffusion and thermophoresis effects generated by the water vapor concentration gradient and flue gas temperature gradient near the tube wall cause fine particles to move towards the tube wall. Simultaneously, the swirling turbulence of the flue gas accelerates the collision between fine particles and the tube wall. A strong adhesive condensate film on the heat exchanger tube wall prevents particle rebound, thus achieving the capture and removal of some fine particles.

[0030] Step 3: The remaining fine particles, under the action of heterogeneous condensation, condense into nuclei of small droplets, which, along with the flue gas, pass through the first heat exchanger 3 and enter the swirling disturbance area of ​​the rotary fan 7. Due to the change in the direction of the swirling disturbance, coupled with the sound waves of a certain frequency and sound pressure level emitted by the fan, the collision and aggregation of the condensation nuclei are enhanced.

[0031] Step 4: The agglomerated particles enter the second heat exchanger 8. The size of the agglomerates and nucleated particles is further increased by the condensation of water vapor, which strengthens the inertial impact with the tube wall of the second heat exchanger 8 and achieves further removal of fine particles.

[0032] Step 5: The agglomerates and nucleated particles that have been further enlarged in size are easily captured by the wire mesh demister 9.

[0033] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A fine particle capture system combining rotating disturbance and flue gas condensation, characterized in that, It includes a swirling air device, a first heat exchanger, a rotary fan, and a second heat exchanger, wherein the swirling air device, the first heat exchanger, the rotary fan, and the second heat exchanger are connected in sequence, and the swirling air device rotates the flue gas in the opposite direction to the rotation of the flue gas by the rotary fan.

2. The fine particle capture system based on rotating disturbance combined with flue gas condensation as described in claim 1, characterized in that, It also includes a wet limestone-gypsum flue gas desulfurization system and a mesh demister. The wet limestone-gypsum flue gas desulfurization system is located at the front end of the swirling air device, and the mesh demister is located at the rear end of the second heat exchanger. The wet limestone-gypsum flue gas desulfurization system, the swirling air device, the first heat exchanger, the rotary fan, the second heat exchanger, and the mesh demister are connected in sequence through a flue gas pipeline.

3. The fine particle capture system based on rotating disturbance combined with flue gas condensation as described in claim 2, characterized in that, The swirling air device consists of air nozzles arranged on the outside of the flue gas duct, with the air outlets of the air nozzles located inside the flue gas duct. The swirling air device sends the flue gas into the first heat exchanger in a spiral shape.

4. The fine particle capture system based on rotating disturbance combined with flue gas condensation as described in claim 1, characterized in that, It also includes a heat pump. The first heat exchanger further includes a first cooling medium water inlet and a first cooling medium water outlet. The second heat exchanger further includes a second cooling medium water inlet and a second cooling medium water outlet. The first cooling medium water inlet, the first cooling medium water outlet, the second cooling medium water inlet, and the second cooling medium water outlet are connected to the heat pump.

5. The fine particle capture system based on rotating disturbance combined with flue gas condensation as described in claim 2, characterized in that, The first heat exchanger has a concave groove directly below the pipe, and a first condensate outlet is provided at the lowest point of the concave groove. The second heat exchanger has a concave groove directly below the pipe, and a second condensate outlet is provided at the lowest point of the concave groove. The first condensate outlet and the second condensate outlet are connected to the wet limestone-gypsum flue gas desulfurization system.

6. The fine particle capture system based on rotating disturbance combined with flue gas condensation as described in claim 1, characterized in that, The second heat exchanger is shorter than the first heat exchanger.

7. The fine particle capture system of rotating disturbance combined with flue gas condensation as described in claim 1, characterized in that, The tube wall temperature of the first and second heat exchangers is lower than the flue gas water dew point temperature.

8. The fine particle capture system of rotating disturbance combined with flue gas condensation as described in claim 1, characterized in that, A condensate film is provided on the tube wall of the first heat exchanger.

9. The fine particle capture system of rotating disturbance combined with flue gas condensation as described in claim 1, characterized in that, Both the first heat exchanger and the second heat exchanger are staggered tube bundle heat exchangers, and both the first heat exchanger and the second heat exchanger are equipped with cleaning devices.

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