Multistage reaction semi-dry absorption tower

Abstract

The utility model relates to a multistage reaction semi-dry absorption tower which comprises an absorbent bin, a water tank, an absorption tower and a dust remover which are integrally designed, and a main induced draft fan and a chimney are arranged behind the dust remover; the absorbent bin is communicated with the absorption tower through an absorbent pipeline; an absorbent feeder for conveying an absorbent, an absorbent ejector and an absorbent feeding fan are arranged on the absorbent pipeline; the water tank is communicated with the absorption tower through a water pipeline; a water pump for conveying water is also arranged on the water pipeline; an absorption tower ash hopper is arranged at the bottom of the absorption tower, the upper end of the absorption tower ash hopper is connected with the bottom of the absorption tower, the lower end of the absorption tower ash hopper is communicated with the absorption tower through a circulating ash return pipeline, an ash hopper fan, an ash hopper feeder and an ash hopper ejector are arranged on the circulating ash return pipeline, and a waste ash bin is further arranged on the circulating ash return pipeline. The circulating ash return pipeline is provided with two or more ash outlets which are communicated with the absorption tower, and the ash outlets have height differences. The device can be widely applied to the field of flue gas treatment.

Description

Technical Field

[0001] The utility model relates to the field of flue gas treatment, in particular to a multi-stage reaction semi-dry absorption tower. Background Art

[0002] In recent years, semi-dry desulfurization has been gradually recognized by users due to its advantages of no wastewater, no white smoke, no secondary pollution and relatively low operating costs. The application of semi-dry desulfurization has gradually become widespread and applied to the carbon industry. However, due to the complex nature of flue gas in the carbon industry, especially the large amount of tar and dust in the flue gas, a large amount of absorbent cannot get a good reaction after entering, and the surface of the absorbent will soon be wrapped by tar and dust, causing the absorbent to lose activity and difficult to humidify. In order to ensure sulfur emissions, it is necessary to continuously increase the amount of absorbent and water. It is not enough to increase the absorbent alone. If the absorbent has no water activity, the absorbent utilization rate is extremely low. However, if the amount of water is increased blindly, the flue gas temperature is easy to drop, which is very easy to cause hardening and the risk of stepping on the bed. This is the problem with the current traditional semi-dry method for the treatment of such high-dust, high-sulfur, tar-containing flue gas. Summary of the invention

[0003] The utility model provides a multi-stage reaction semi-dry absorption tower with a single tower and multiple layers of reactions in order to solve the technical problem that the existing semi-dry desulfurization technology is difficult to handle complex flue gases such as high dust, high sulfur, tar, and hydrogen fluoride.

[0004] The utility model provides a multi-stage reaction semi-dry absorption tower, which is provided with an absorbent bin, a water tank, an absorption tower and a dust collector of integrated design, a main induced draft fan and a chimney are arranged behind the dust collector; the absorbent bin is communicated with the absorption tower through an absorbent pipeline, an absorbent feeder, an absorbent ejector and an absorbent feeding fan for conveying absorbent are arranged on the absorbent pipeline; the water tank is communicated with the absorption tower through a water pipeline, and a water pump for conveying water is also arranged on the water pipeline; an absorption tower ash hopper is arranged at the bottom of the absorption tower, the upper end of the absorption tower ash hopper is connected to the bottom of the absorption tower, the lower end of the absorption tower ash hopper is communicated with the absorption tower through a circulating ash return pipeline, an ash hopper fan, an ash hopper feeder and an ash hopper ejector are arranged on the circulating ash return pipeline, a waste ash bin is also arranged on the circulating ash return pipeline, two or more ash outlets are arranged on the circulating ash return pipeline to lead into the absorption tower, and each of the ash outlets has a height difference.

[0005] Preferably, the absorption tower is U-shaped, the upper front end of the U-shaped absorption tower inlet is provided at the absorption tower inlet, a stirring and material equalizing device is provided at the absorption tower inlet, and the dust collector is arranged at the upper rear end of the U-shaped absorption tower.

[0006] Preferably, the absorption tower ash hopper is provided with a front ash hopper and a rear ash hopper in sequence according to the direction of the flue gas, and the front ash hopper and the rear ash hopper are respectively provided with a circulating ash return pipeline connected to the absorption tower, and the circulating ash return pipeline is provided with an electric valve for controlling the on-off of the pipeline.

[0007] Preferably, the circulating ash return pipeline of the rear ash hopper is provided with three or more ash outlets with different heights leading to the absorption tower.

[0008] Preferably, the dust collector is provided with two dust collector ash hoppers, and the dust collector ash hoppers are connected to the inlet of the absorption tower through a pipeline with a feeder.

[0009] Preferably, the water pipelines are two or more water pipelines with different heights.

[0010] Preferably, the height distance between each ash outlet is 2-3.5 meters.

[0011] Beneficial effects of the utility model:

[0012] The utility model aims at the problems of difficult humidification of the existing semi-dry absorbent, stepping bed, low utilization rate of absorbent and large resistance, and adopts the mode of "single tower multi-layer reaction + high density of absorbent in the tower + humidification in the tower" to completely solve the treatment problems of complex flue gas such as high tar, dust and high sulfur. The mode of combining single tower multi-layer reaction plus high density of absorbent plus multi-layer humidification in the tower is adopted. The single tower multi-layer reaction can realize multiple contacts between flue gas and absorbent, and multiple reactions of flue gas are realized. Therefore, the multi-layer arrangement of the absorbent injection pipeline also increases the density of absorbent in the absorption tower, thereby greatly increasing the contact time between flue gas and absorbent. In addition, the rise of absorbent is carried out by pneumatic conveying outside the tower instead of being carried up by the high flow rate of flue gas in the tower. In this way, the wind speed requirement in the tower will not be very high, so the resistance of the entire absorption tower will not be very high. At present, the resistance of the absorption tower is 500-700Pa, which is much lower than the resistance of the absorption tower of the traditional circulating fluidized bed technology absorption tower of 1500-1700Pa.

[0013] The tower is humidified with two layers of water spray points, one high and one low, to evenly humidify the high-density absorbent. When sulfur emissions are controllable, only the low-position humidification nozzle can be opened. When the sulfur content and flue gas temperature are high, the high-position humidification nozzle can be opened. After the absorbent falls to the ash hopper at the bottom of the absorption tower, it returns to the tower to participate in the reaction through pneumatic conveying. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the utility model.

[0015] Description of the accompanying symbols:

[0016] 1. Dust collector; 2. Water tank; 3. High-level water pump; 4. Mixing and equalizing device; 5. Dust collector ash hopper feeder 1; 6. Low-level water pump; 7. Absorbent bin; 8. Absorbent feeder; 9. Absorbent ejector; 10. Absorbent feeding fan; 11. Absorbent hopper feeder No. 1; 12. Absorbent hopper ejector No. 1; 13. Roots blower No. 1; 14. Roots blower No. 2; 15. Absorbent hopper feeder No. 2; 16. Absorbent hopper No. 2 Ejector; 17. Waste ash bin; 18. Ash discharge valve; 19. Absorption tower; 20. Low-level humidification nozzle; 21. Electric valve for the return line of No. 1 ash hopper of absorption tower; 22. Electric valve for the return line of No. 1 ash hopper of absorption tower; 23. High-level humidification nozzle; 24. Electric valve for the return line of No. 2 ash hopper of absorption tower; 25. Dust collector ash hopper feeder 2; 26. Electric valve for the return line of No. 3 ash hopper of absorption tower; 27. Main induced draft fan; 28. Chimney. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with the accompanying drawings and embodiments so that those skilled in the art can easily implement the present invention.

[0018] Example 1: Figure 1 As shown, this embodiment is a flue gas treatment module, which adopts an integrated design of an absorption tower 19 and a dust collector 1, and the dust collector 1 is above the absorption tower 19. The bottom of the absorption tower 19 has two ash hoppers. The bottoms of the two ash hoppers are connected to the absorption tower No. 1 ash hopper feeder 11 and the absorption tower No. 2 ash hopper feeder 15, and the lower parts of the feeders are respectively connected to the absorption tower No. 1 ash hopper ejector 12 and the absorption tower No. 2 ash hopper ejector 16, and the ejectors are respectively connected to the No. 1 Roots blower 13 and the No. 2 Roots blower 14 through pipelines. There is only one circulation pipeline entering the tower behind the absorption tower No. 1 ash hopper ejector 12, and the absorption tower No. 1 ash hopper return pipeline electric valve 21 is installed on the pipeline; the return pipeline behind the absorption tower No. 2 ash hopper ejector 16 is divided into three layers to enter the tower, and the absorption tower No. 2 ash hopper return pipeline No. 1 electric valve 22, the absorption tower No. 2 ash hopper return pipeline No. 2 electric valve 24 and the absorption tower No. 2 ash hopper return pipeline No. 3 electric valve 26 are installed on the three layers of pipelines, and an ash discharge pipeline is installed on the main pipeline to connect the waste ash bin 17, and an ash discharge valve 18 is installed on the ash discharge pipeline. The electric valve 21 of the absorption tower No. 1 ash hopper return pipeline, the electric valve 22 of the absorption tower No. 2 ash hopper return pipeline, the electric valve 24 of the absorption tower No. 2 ash hopper return pipeline and the electric valve 26 of the absorption tower No. 2 ash hopper return pipeline control the corresponding ash outlets. There is a height difference between the ash outlets, and the ash outlets are arranged in sequence with a height spacing of 2-3.5 meters.

[0019] Two layers of water-adding humidifying nozzles are arranged near the ash outlet, the water tank 2 is separately connected to the high-level water pump 3 and the low-level water pump 6, the water pumps are respectively connected to the low-level humidifying nozzle 23 and the low-level humidifying nozzle 20 by pipelines, the nozzles are arranged inside the lower absorption tower, the nozzles can adopt a dual-fluid spray gun or a reflux nozzle, but to ensure the atomization effect, the low-level humidifying nozzle 20 should be arranged near the middle position between the ash outlet of the absorption tower No. 1 ash hopper return tower circuit and the ash outlet of the absorption tower No. 2 ash hopper return tower No. 1 pipeline, specifically should be arranged at the position of 1 / 3-2 / 3, the high-level humidifying nozzle 23 is arranged near the middle position between the ash outlet of the absorption tower No. 2 ash hopper return tower No. 2 pipeline and the ash outlet of the No. 3 pipeline, specifically should be arranged at the position of 1 / 3-2 / 3.

[0020] An absorbent feeder 8 and an absorbent injector 9 are sequentially installed at the bottom of the absorbent bin 7. An absorbent feed blower 10 is installed in front of the absorbent injector 9 and then directly connected to the absorption tower through a pipeline.

[0021] The absorption tower 19 is a "U"-shaped structure, with two ash hoppers at the bottom of the absorption tower. The circulating ash in one ash hopper is directly pneumatically conveyed back to the absorption tower, and the absorption ash in the other ash hopper is pneumatically conveyed back to the absorption tower in multiple ways after being discharged. A stirring and homogenizing device 4 is provided at the smoke inlet of the absorption tower 19.

[0022] The dust collector 1 is provided with two ash hoppers, and the dust collector ash hopper feeder 1 5 and the dust collector ash hopper feeder 2 25 are installed at the bottom of the ash hopper respectively, and the feeders are connected to the absorption tower inlet through pipelines. A main induced draft fan 27 and a chimney 28 are arranged behind the dust collector 1.

[0023] As shown in Table 1, this embodiment compares the number of flue gas humidification opening layers and the number of desulfurization tower return circuit opening layers for different SO2 contents.

[0024]

[0025]

[0026] Table 1

[0027] In this embodiment, when the first layer of humidification is turned on, the SO2 content of the inlet flue gas is less than 2000 mg / Nm 3 The outlet flue gas can reach 35mg / Nm 3 Below. If the imported SO2 content is > 2000mg / Nm 3 The export will exceed the standard, and a desulfurization system needs to be used in series to achieve the goal of meeting the export SO2 emission standards.

[0028] In this embodiment, the desulfurization cycle and water humidification are both set up with multiple layers. The number of layers to be opened can be determined according to the sulfur content of the flue gas. The inlet SO2 content is ≤800mg / Nm 3, the bottom layer can be opened to add water and humidify, and the desulfurized ash returns to the tower to open the top desulfurization tower return loop; the imported SO2 content is >800mg / Nm 3 <1500mg / Nm 3 , open two layers of water to add humidification, and return the desulfurized ash to the tower. Open the return loop of the top two layers of desulfurization tower; the inlet SO2 content is >1500mg / Nm 3 <2000mg / Nm 3 Open two layers of water to add humidification, and return the desulfurized ash to the tower to open the three-layer desulfurization tower return loop. Flexible operation can make the flue gas realize multi-stage reaction in a single tower, achieving the effect of multiple towers in series. It can be adapted to the treatment of complex flue gases such as high tar, dust and high sulfur.

[0029] Example 2: The smoke volume processed by one module of the utility model is 300,000-400,000 m 3 / h, the module can be added according to the actual working condition flue gas volume. For example: the actual working condition flue gas volume is 1.2 million m 3 / h, 3 modules are required.

[0030] The above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. For those skilled in the art, the utility model may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the scope of the claims of the utility model shall be within the scope of protection of the utility model.

Claims

1. A multi-stage reaction semi-dry absorption tower, which is provided with an absorbent bin, a water tank, an absorbent tower and a dust collector of integrated design, wherein a main induced draft fan and a chimney are arranged behind the dust collector; the absorbent bin is communicated with the absorbent tower through an absorbent pipeline, and an absorbent feeder, an absorbent ejector and an absorbent feeding fan for conveying absorbent are arranged on the absorbent pipeline; the water tank is communicated with the absorbent tower through a water pipeline, and a water pump for conveying water is also arranged on the water pipeline; an absorbent ash hopper is arranged at the bottom of the absorbent tower, the upper end of the absorbent ash hopper is connected to the bottom of the absorbent tower, and the lower end of the absorbent ash hopper is communicated with the absorbent tower through a circulating ash return pipeline, and an ash hopper fan, an ash hopper feeder and an ash hopper ejector are arranged on the circulating ash return pipeline, and a waste ash bin is also arranged on the circulating ash return pipeline, wherein the waste ash bin is characterized in that: The circulating ash return pipeline is provided with two or more ash outlets leading to the absorption tower, and each of the ash outlets has a height difference.

2. The multi-stage reaction semi-dry absorption tower according to claim 1, characterized in that: The absorption tower is U-shaped, the upper front end of the U-shaped absorption tower inlet is provided at the absorption tower inlet, a stirring and material-averaging device is provided at the absorption tower inlet, and the dust collector is provided at the upper rear end of the U-shaped absorption tower.

3. The multi-stage reaction semi-dry absorption tower according to claim 2, characterized in that: The absorption tower ash hopper is provided with a front ash hopper and a rear ash hopper in sequence according to the direction of the flue gas. The front ash hopper and the rear ash hopper are respectively provided with circulating ash return pipelines connected to the absorption tower. The circulating ash return pipelines are provided with electric valves for controlling the on-off of the pipelines.

4. The multi-stage reaction semi-dry absorption tower according to claim 3, characterized in that: The circulating ash return pipeline of the rear ash hopper is provided with three or more ash outlets with different heights leading to the absorption tower.

5. The multi-stage reaction semi-dry absorption tower according to claim 2, characterized in that: The dust collector is provided with two dust collector ash hoppers, and the dust collector ash hoppers are connected to the inlet of the absorption tower through a pipeline with a feeder.

6. The multi-stage reaction semi-dry absorption tower according to claim 1, characterized in that: The water pipelines are two or more water pipelines with height differences.

7. The multi-stage reaction semi-dry absorption tower according to claim 1, characterized in that: The height distance between each ash outlet is 2-3.5 meters.

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