A desulfurization and denitrification equipment for thermal power plants

Abstract

The application discloses a kind of thermal power plant desulfurization and denitrification equipment, it is related to thermal power plant flue gas treatment technical field, including absorption tower, the top of the absorption tower is provided with first separation mechanism and second separation mechanism, the top of the second separation mechanism is further provided with composite demister;The first separation mechanism includes the mouthpiece of erection in the upper portion of the absorption tower, the top of the mouthpiece is provided with first spiral flue, the first spiral flue is provided with first demister outside sleeve joint installation;The second separation mechanism includes the second spiral flue of erection in the upper portion of the first spiral flue, the second spiral flue is provided with second demister outside sleeve joint installation, the composite demister is distributed in the first demister and the top of the second demister.The thermal power plant desulfurization and denitrification equipment disclosed in the application has the effect of high purification efficiency, high stability.

Description

Technical Field

[0001] This invention relates to the field of flue gas treatment technology for thermal power plants, and in particular to a desulfurization and denitrification device for thermal power plants. Background Technology

[0002] Wet flue gas desulfurization is the mainstream desulfurization process in thermal power plants. In the desulfurization and denitrification absorption tower, the flue gas after spray desulfurization treatment carries a large number of slurry droplets upwards. It needs to be separated into gas and liquid by a demister set at the top of the tower to prevent droplets from depositing on the surface of downstream equipment to form gypsum scale or causing "rain" from the chimney to pollute the environment. Most demisters in the existing technology adopt a folded plate structure. Since the folded plate demister relies on the turbulence characteristics to scrape off and intercept the moisture in the flue gas, the more turbulent the airflow, the better the moisture interception effect.

[0003] Existing demister installation methods typically involve horizontally arranging the demister at the top of the absorption tower, with flue gas flowing vertically upwards through the demister channel. Moisture trapped by the demister is held on the surface of the baffle plates. Due to this limitation, the flue gas velocity in traditional baffle-type demisters can usually only be maintained at 2.4~3.6 m / s. If the velocity is too high, the captured droplets will be re-carried by the flue gas, causing secondary water carryover and significantly reducing demister efficiency. Furthermore, existing demisters generally suffer from poor airflow turbulence. Better airflow turbulence results in better demister performance. Therefore, improving flue gas turbulence while simultaneously preventing secondary water carryover has become a key technical challenge for enhancing demister performance. Summary of the Invention

[0004] This invention discloses a desulfurization and denitrification equipment for thermal power plants, which aims to solve the technical problem that the stability and completeness of the demisters used in existing desulfurization and denitrification equipment for thermal power plants need to be improved.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A desulfurization and denitrification device for a thermal power plant includes an absorption tower. The top of the absorption tower is provided with a first separation mechanism and a second separation mechanism for graded purification of flue gas. The second separation mechanism is located on top of the first separation mechanism. Above the second separation mechanism, a composite demister for combined purification of flue gas is further provided.

[0007] The first separation mechanism includes a closing member installed above the inside of the absorption tower. The top of the closing member is provided with a first spiral channel. A first demister is sleeved on the outside of the first spiral channel. The closing member and the first demister are connected through the first spiral channel.

[0008] The second separation mechanism includes a second spiral channel mounted above the first spiral channel. A second demister is sleeved on the outer side of the second spiral channel. The spiral direction of the second spiral channel is opposite to that of the first spiral channel. The composite demister is distributed directly above the first demister and the second demister.

[0009] Based on the existing demisting equipment and technology used in desulfurization and denitrification equipment in thermal power plants, two sets of staggered separation mechanisms are set up. First, the rising flue gas is graded using two separate spiral channel structures, and the direction of flue gas movement is changed. The flue gas enters the interior of the channel along the spiral state for separation. Second, the flue gas is purified first by the two spiral channels in conjunction with a separate demister, and then the mixed flue gas is purified a second time by a composite demister, which greatly improves the demisting efficiency of traditional equipment.

[0010] In a preferred embodiment, a settling tank is fitted onto the outer side of the second spiral channel. The settling tank is located directly below the second demister. A guide pipe is connected through the side wall of the settling tank, and the guide pipe extends from the interior of the absorption tower.

[0011] By further installing a sedimentation tank structure along the bottom of the second demister, the settled droplets are continuously collected in the sedimentation tank and discharged to the absorption tower through the guide pipe, thereby maintaining the integrity of the equipment operation.

[0012] In a preferred embodiment, the top outer edge of the second demister is provided with a flared part.

[0013] By further providing a flared structure along the top of the second demister, the flue gas discharged from the inside of the second demister is diffused outward by the flared structure, causing the flue gas to mix with the flue gas discharged from the first demister and generating turbulence, thereby improving the working efficiency of the subsequent composite demister.

[0014] In a preferred embodiment, the main structures of the first demister, the second demister, and the composite demister are all composed of a number of closely arranged intercepting baffles. The horizontal height of the intercepting baffles located inside the first demister and the second demister is higher than that of the first spiral channel and the second spiral channel, respectively. Flow channels are reserved between each pair of intercepting baffles. The flue gas enters the interior of the flow channels in a spiral upward state, and the generated droplets move out from the bottom of the flow channels in a vertical direction. The flue gas ejected from the first spiral channel and the second spiral channel moves upward in a spiral shape and passes through the flow channels upward.

[0015] By setting up a demister structure with intercepting baffles as the main body, the flow direction of the vertically moving flue gas is changed by using the first spiral channel and the second spiral channel, so that the flue gas enters the interior of the channel in a spiral state. This avoids the problem that droplets have to overcome the drag of the flue gas to fall in the traditional structure, resulting in more thorough droplet separation and a significant reduction in the moisture content of the outlet flue gas.

[0016] Each of the intercepting baffles is provided with a first turbulence scraper in the middle and a second turbulence scraper at the top of each of the intercepting baffles. The interior of the absorption tower is provided with several sets of evenly distributed spray pipes in layers, and the spray pipes spray alkaline absorbent into the interior of the absorption tower.

[0017] As can be seen from the above, the desulfurization and denitrification equipment for thermal power plants provided by the present invention has the following technical effects.

[0018] Firstly, by setting up two sets of staggered separation mechanisms, the rising flue gas is graded using two separate spiral channel structures. At the same time, the direction of flue gas movement is reversed, and the flue gas enters the interior of the channel in a spiral state. Taking advantage of the longer travel distance and weaker longitudinal traction of the spiral airflow, the problem that droplets must overcome the strong vertical drag of the flue gas to fall in the traditional structure is avoided. Moreover, the turbulence between the spiral airflow and the intercepting baffle is stronger, making the interception and separation of droplets more thorough and significantly reducing the moisture content of the outlet flue gas.

[0019] Secondly, the flue gas is first purified by two spiral channels in conjunction with a separate demister, and then the mixed flue gas is purified a second time by a composite demister. The flue gas purified first will be turbulent and mixed, thereby greatly improving the demisting efficiency of the composite demister.

[0020] Thirdly, the first and second turbulence scrapers will improve the turbulence effect of the interception baffle on the flue gas, and the structure is bent downwards. Since the flue gas moves upwards as a whole, the efficiency of scraping and intercepting droplets can be improved. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure proposed in this invention.

[0022] Figure 2 This is a cross-sectional view of the overall structure proposed in this invention.

[0023] Figure 3 This is a schematic diagram of the composite demister structure proposed in this invention.

[0024] Figure 4 This is a schematic diagram of the bottom structure of the sealing member proposed in this invention.

[0025] Figure 5 This is a schematic diagram of the ventilation opening structure proposed in this invention.

[0026] Figure 6 This is an exploded view of the first separation mechanism proposed in this invention.

[0027] Figure 7 This is an exploded view of the second separation mechanism proposed in this invention.

[0028] Figure 8 The present invention proposes Figure 7 Enlarged view of the structure at point A in the middle.

[0029] Figure 9 This is a schematic diagram of the flue gas flow direction under cross-sectional view as proposed in this invention.

[0030] In the diagram: 1. Absorption tower; 2. First separation mechanism; 201. Closing component; 202. First spiral channel; 203. First demister; 204. Ventilation port; 3. Second separation mechanism; 301. Second spiral channel; 302. Sedimentation tank; 303. Second demister; 304. Flaring component; 305. Guide pipe; 4. Composite demister; 5. Spray pipe; 6. Interceptor baffle; 601. First turbulence scraper; 602. Second turbulence scraper; 7. Flow channel. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0032] The desulfurization and denitrification equipment disclosed in this invention is mainly used in the scenario of purifying the exhaust gas generated by thermal power plants.

[0033] Reference Figures 1 to 9 A desulfurization and denitrification device for a thermal power plant includes an absorption tower 1. The top of the absorption tower 1 is provided with a first separation mechanism 2 and a second separation mechanism 3 for graded purification of flue gas. The second separation mechanism 3 is located on top of the first separation mechanism 2. Above the second separation mechanism 3, a composite demister 4 for composite purification of flue gas is further provided.

[0034] The first separation mechanism 2 includes a closing member 201 installed above the inside of the absorption tower 1. A first spiral channel 202 is provided on the top of the closing member 201. A first demister 203 is sleeved on the outside of the first spiral channel 202. The closing member 201 and the first demister 203 are connected through the first spiral channel 202.

[0035] The second separation mechanism 3 includes a second spiral channel 301 mounted above the first spiral channel 202. A second demister 303 is sleeved on the outer side of the second spiral channel 301. The spiral direction of the second spiral channel 301 is opposite to that of the first spiral channel 202. The composite demister 4 is distributed directly above the first demister 203 and the second demister 303.

[0036] In this embodiment: the saturated wet flue gas after spray denitrification and desulfurization will rise vertically from the bottom of the absorption tower 1. At this time, the flue gas will first enter the interior of the first spiral channel 202, and a portion of it will enter the interior of the second spiral channel 301. The flue gas discharged along the interior of the first spiral channel 202 and the second spiral channel 301 will be blown outward in a spiral shape, and will pass upward through the first demister 203 and the second demister 303 respectively, thereby being filtered by the first demister 203 and the second demister 303, intercepting the liquid droplets in the wet flue gas. The liquid droplets will drip vertically from the interior of the first demister 203 and the second demister 303. At this time, the two flue gases that continue to rise will mix and enter the interior of the composite demister 4. After further purification by the composite demister 4, it will be discharged from the top of the absorption tower 1.

[0037] Since the horizontal height of the intercepting baffle 6 located inside the first demister 203 and the second demister 303 is higher than that of the first spiral channel 202 and the second spiral channel 301, respectively, the flue gas ejected from the first spiral channel 202 and the second spiral channel 301 moves upward in a spiral shape and passes upward through the flow channel 7. This increases the horizontal displacement of the spiraling flue gas, which will increase the contact time and turbulence effect between the flue gas and the intercepting baffle 6, thereby improving the interception efficiency of droplets in the flue gas. Furthermore, it is worth noting that when the flue gas comes into contact with the droplets intercepted on the intercepting baffle 6, the spiral path will reduce the probability of the droplets detaching from the intercepting baffle 6 in the vertical direction, thereby reducing the moisture content of the flue gas.

[0038] The top of the first spiral tunnel 202 is provided with a ventilation opening 204, and the second spiral tunnel 301 is connected through the ventilation opening 204.

[0039] Furthermore, a settling tank 302 is fitted onto the outer side of the second spiral channel 301. The settling tank 302 is located directly below the second demister 303. A guide pipe 305 is connected through the side wall of the settling tank 302. The guide pipe 305 extends from the inside of the absorption tower 1 and is filtered by the first demister 203 and the second demister 303, which intercepts the droplets in the wet flue gas. The droplets drip from the first demister 203 and the second demister 303 in a vertical direction. The droplets dripping from the second demister 303 accumulate inside the settling tank 302 and are eventually discharged from the inside of the absorption tower 1 through the guide pipe 305.

[0040] Reference Figures 3 to 8 In a preferred embodiment, the main structure of the first demister 203, the second demister 303, and the composite demister 4 is composed of several closely arranged intercepting baffles 6. A flow channel 7 is reserved between each pair of intercepting baffles 6. The flue gas enters the interior of the flow channel 7 in a spiral state, and the generated droplets move out from the bottom of the flow channel 7 in a vertical direction.

[0041] The flue gas discharged along the first spiral channel 202 and the second spiral channel 301 will spiral into the intercepting baffles 6 of the first demister 203 and the second demister 303 respectively. The flue gas will move along the inside of the flow channel 7 and be scraped and filtered by the intercepting baffles 6, intercepting the liquid droplets in the wet flue gas. The liquid droplets will drip vertically from the inside of the flow channel 7 of the first demister 203 and the second demister 303. The liquid droplets dripping from the second demister 303 will accumulate inside the sedimentation tank 302 and finally be discharged from the inside of the absorption tower 1 through the guide pipe 305.

[0042] It is worth noting that, such as Figure 9 As shown, the top outer edge of the second demister 303 is provided with a flared part 304, which causes the flue gas discharged from the second demister 303 to be dispersed obliquely upward and to turbulently interact with the flue gas discharged from the first demister 203. This results in the flue gas passing through the composite demister 4 being in a turbulent state. Because the turbulent airflow can improve the demisting effect of the intercepting baffle 6 of the composite demister 4, the flow direction of the flue gas is as follows: Figure 9 As shown by the arrow in the image.

[0043] Each intercepting baffle 6 has a first turbulence scraper 601 in the middle and a second turbulence scraper 602 at the top. The first turbulence scraper 601 and the second turbulence scraper 602 improve the turbulence effect of the intercepting baffle 6 on the flue gas, and the structure is bent downwards. Since the flue gas moves upward as a whole, the efficiency of the liquid droplet removal and interception can be improved.

[0044] Reference Figure 1 and Figure 2 In a preferred embodiment, the interior of the absorption tower 1 is equipped with several sets of evenly distributed spray pipes 5 arranged in layers. The spray pipes 5 spray an alkaline absorbent (such as limestone slurry) into the interior of the absorption tower 1. It is worth noting that since over 90% of the NO in the flue gas is poorly soluble in water, it is necessary to add [a specific additive] first. , Oxidizing agents oxidize NO into water-soluble compounds. The nitrogen oxides are then removed by absorption with an alkaline absorbent solution. This is an existing technique and will not be described in detail here.

[0045] Working principle: During operation, flue gas rises vertically from the bottom of the absorption tower 1. Then, limestone slurry is sprayed downwards from the multi-layer spray pipes 5. The flue gas and sprayed slurry flow counter-currently and mix. Sulfur dioxide in the flue gas reacts chemically with the limestone slurry, and after oxidation by oxidizing air, it forms calcium sulfate dihydrate. The sulfur dioxide is absorbed. At this point, the desulfurized flue gas, carrying droplets, first enters the interior of the first spiral duct 202, and a portion is diverted into the interior of the second spiral duct 301. The flue gas discharged along the first spiral duct 202 and the second spiral duct 301 spirals into the first demister 203 and the second demister 303 respectively for interception. Inside plate 6, the flue gas moves along the inside of the flow channel 7 and is scraped and filtered by the intercepting baffle 6, which intercepts the droplets in the wet flue gas. The droplets drip vertically from the inside of the flow channel 7 of the first demister 203 and the second demister 303. The droplets dripping from the second demister 303 will accumulate inside the sedimentation tank 302 and finally be discharged from the inside of the absorption tower 1 through the guide pipe 305 (the guide pipe 305 is equipped with a one-way valve to prevent the external airflow from flowing back into the inside of the absorption tower 1). At this time, the two flue gases that continue to rise will mix and enter the inside of the composite demister 4. After being purified by the composite demister 4, they are discharged from the top of the absorption tower 1.

[0046] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A desulfurization and denitrification device for a thermal power plant, comprising an absorption tower (1), characterized in that, The top of the absorption tower (1) is provided with a first separation mechanism (2) and a second separation mechanism (3) for graded purification of flue gas. The second separation mechanism (3) is located on top of the first separation mechanism (2). Above the second separation mechanism (3) is a composite demister (4) for composite purification of flue gas. The first separation mechanism (2) includes a closing member (201) installed above the inside of the absorption tower (1). The top of the closing member (201) is provided with a first spiral channel (202). A first demister (203) is sleeved on the outside of the first spiral channel (202). The closing member (201) and the first demister (203) are connected through the first spiral channel (202) and the first demister (203). The second separation mechanism (3) includes a second spiral channel (301) mounted above the first spiral channel (202). A second demister (303) is sleeved on the outside of the second spiral channel (301). The spiral direction of the second spiral channel (301) is opposite to that of the first spiral channel (202). The composite demister (4) is distributed directly above the first demister (203) and the second demister (303). The intercepting baffle (6) located inside the first demister (203) and the second demister (303) is at a horizontal height higher than the first spiral channel (202) and the second spiral channel (301), respectively.

2. The desulfurization and denitrification equipment for thermal power plants according to claim 1, characterized in that, The top of the first spiral channel (202) is provided with a ventilation opening (204), and the second spiral channel (301) is connected through the ventilation opening (204).

3. The desulfurization and denitrification equipment for thermal power plants according to claim 1, characterized in that, A settling tank (302) is fitted onto the outer side of the second spiral channel (301), and the settling tank (302) is located directly below the second demister (303).

4. The desulfurization and denitrification equipment for thermal power plants according to claim 1, characterized in that, The second demister (303) has a flared part (304) on the top outer edge.

5. The desulfurization and denitrification equipment for thermal power plants according to claim 3, characterized in that, The side wall of the sedimentation tank (302) is connected to a guide pipe (305), which extends from the inside of the absorption tower (1).

6. The desulfurization and denitrification equipment for thermal power plants according to claim 1, characterized in that, The main structures of the first demister (203), the second demister (303) and the composite demister (4) are all composed of several closely arranged intercepting baffles (6).

7. The desulfurization and denitrification equipment for thermal power plants according to claim 6, characterized in that, The intercepting baffles (6) leave a flow channel (7) between each other. The flue gas enters the interior of the flow channel (7) in a spiral upward state, and the generated droplets move out from the bottom of the flow channel (7) in a vertical direction.

8. The desulfurization and denitrification equipment for thermal power plants according to claim 6, characterized in that, The flue gas ejected from the first spiral channel (202) and the second spiral channel (301) moves upward in a spiral shape and passes upward through the flow channel (7).

9. A desulfurization and denitrification equipment for a thermal power plant according to claim 6, characterized in that, Each of the intercepting baffles (6) is provided with a first turbulence scraper (601) at the middle and a second turbulence scraper (602) at the top of each of the intercepting baffles (6).

10. A desulfurization and denitrification equipment for a thermal power plant according to claim 1, characterized in that, The absorption tower (1) is equipped with several sets of evenly distributed spray pipes (5) in layers inside, and the spray pipes (5) spray alkaline absorbent into the absorption tower (1).

Images