Flue gas desulfurization system

Abstract

The utility model discloses a flue gas desulfurization system and belongs to the technical field of desulfurization devices. The flue gas desulfurization system comprises a sulfur dioxide absorption system, an alkali liquor storage system, an oxidation system and a process water system, the sulfur dioxide absorption system comprises an absorption tower and a slurry recirculation system, a circulating slurry pond, a rectification layer, a spraying layer, a demisting device and an auxiliary flushing device are sequentially arranged in the absorption tower from bottom to top, and the bottom of the circulating slurry pond is communicated with an inlet of the slurry recirculation system through a pipeline; an outlet of the slurry recycling system is communicated with the spraying layer through a pipeline; the flue gas inlet is formed in the side wall of the absorption tower; a top outlet of the absorption tower is communicated with a chimney through a pipeline. The flue gas desulfurization system disclosed by the utility model is simple and compact in overall structure, relatively low in investment cost, convenient to maintain, relatively high in desulfurization reaction speed and relatively high in desulfurization efficiency, and has a very good application prospect.

Description

Technical Field

[0001] This utility model belongs to the technical field of desulfurization devices, specifically relating to a flue gas desulfurization system. Background Technology

[0002] With the acceleration of industrialization, the flue gas produced during the combustion of coal, oil, and gas contains large amounts of sulfur dioxide (SO2) and nitrogen oxides (NOx). x Pollutants such as particulate matter and particulate matter cause serious air pollution, leading to environmental problems such as acid rain and smog, which severely impact human health and ecological balance. Therefore, environmental regulations in various countries have imposed increasingly stringent requirements on the concentration of pollutants emitted into flue gas, driving the continuous development of flue gas desulfurization technology.

[0003] Currently, flue gas desulfurization (FGD) technologies are mainly classified into three categories: wet FGD, dry FGD, and semi-dry FGD. Among them, wet FGD technology is the most widely used, especially the lime / limestone-gypsum method, which absorbs SO2 from flue gas through limestone slurry, generating gypsum as a byproduct. However, this method suffers from problems such as complex equipment, high investment costs, difficult operation and maintenance, and the generation of a large amount of byproducts that need to be treated. Therefore, developing a highly efficient, economical, environmentally friendly, and adaptable FGD system is of significant practical importance. Utility Model Content

[0004] To solve the above-mentioned technical problems, this utility model provides a flue gas desulfurization system. The flue gas desulfurization system of this utility model has a simple and compact overall structure, low investment cost, convenient maintenance, fast desulfurization reaction speed, and high desulfurization efficiency, and has very good application prospects.

[0005] The technical solution of this utility model is as follows:

[0006] This utility model provides a flue gas desulfurization system, including a sulfur dioxide absorption system, an alkali storage system, an oxidation system, and a process water system. The sulfur dioxide absorption system includes an absorption tower and a slurry recirculation system. The absorption tower, from bottom to top, includes a circulating slurry tank, a rectifying layer, a spray layer, a demister, and an auxiliary flushing device. The demister consists of a single-stage tubular demister and a two-stage ridge demister. The auxiliary flushing device is connected to the process water system via a pipeline. The alkali storage system includes an alkali tank and a bubbling device located at the bottom of the alkali tank. The bubbling device is connected to the air inlet via a pipeline, and the sidewall of the alkali tank is connected to the bottom of the circulating slurry tank via a pipeline. The system is interconnected, with regulating valves installed on the pipelines. The oxidation system includes an oxidation tank and an air duct network located at the bottom of the oxidation tank. The air duct network is connected to the outlet of the blower via a pipeline. A humidification and cooling device is installed at the inlet of the blower. The outlet of the oxidation tank is connected to the slurry discharge pump via a pipeline. The top of the circulating slurry tank is connected to the top of the oxidation tank via a pipeline. The bottom of the circulating slurry tank is connected to the inlet of the slurry recirculation system via a pipeline. The outlet of the slurry recirculation system is connected to the spray layer via a pipeline. The flue gas inlet is located on the side wall of the absorption tower, between the rectifier layer and the circulating slurry tank. The top outlet of the absorption tower is connected to the chimney via a pipeline.

[0007] Based on the above technical solution, the spray layer further comprises a distribution pipe and spiral nozzles installed on the distribution pipe, with the spiral nozzles facing the bottom of the absorption tower.

[0008] Based on the above technical solution, a regulating valve is further installed on the pipeline between the top of the circulating slurry tank and the top of the oxidation tank.

[0009] Based on the above technical solution, the number of rectifier layers is 1 to 5, and it is a pipe grid structure; the slurry recirculation system includes 2 to 6 circulation pumps, and the number of spray layers is 2 to 6.

[0010] Based on the above technical solution, the absorption tower is further shaped into a cylindrical shape.

[0011] Based on the above technical solution, furthermore, the pipeline between the auxiliary flushing device and the process water system is equipped with pumps and valves.

[0012] Based on the above technical solution, a pH measuring device is further installed in the circulating slurry tank inside the absorption tower.

[0013] Compared with the prior art, the present invention achieves the following beneficial effects:

[0014] The flue gas desulfurization system of this invention has a simple and compact overall structure, low investment cost, convenient maintenance, fast desulfurization reaction speed, and high desulfurization efficiency, and has a very good application prospect. Attached Figure Description

[0015] To clearly illustrate the embodiments of this utility model, the accompanying drawings related to the embodiments will be briefly described below.

[0016] Figure 1 This is a schematic diagram of the flue gas desulfurization system of this utility model, wherein 1: absorption tower, 2: slurry recirculation system, 3: circulating slurry pool, 4: rectification layer, 5: spray layer, 6: tubular demister, 7: ridge demister, 8: auxiliary flushing device, 9: process water system, 10: alkali tank, 11: bubbling device, 12: oxidation tank, 13: air pipeline, 14: fan, 15: humidification and cooling device, 16: slurry discharge pump, 17: circulation pump, 18: chimney, 19: flue gas inlet, 20: air inlet. Detailed Implementation

[0017] The present invention will be described in detail below with reference to the embodiments. However, the implementation of the present invention is not limited thereto. Obviously, the embodiments described below are only some embodiments of the present invention. For those skilled in the art, other similar embodiments can be obtained without creative effort and all fall within the protection scope of the present invention.

[0018] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", "front", "back", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0019] Example 1

[0020] This utility model provides a flue gas desulfurization system, such as Figure 1As shown, it includes a sulfur dioxide absorption system, an alkali storage system, an oxidation system, and a process water system 9. The sulfur dioxide absorption system includes an absorption tower 1 and a slurry recirculation system 2. The slurry recirculation system 2 includes four circulating pumps 17. The absorption tower 1 is cylindrical, and from bottom to top, it is equipped with a circulating slurry pool 3, two rectifying layers 4 (the rectifying layers are of a pipe grid structure), four spray layers 5, a demister (used to remove mist droplets entrained in the flue gas), and an auxiliary flushing device 8 (used to flush...). The demisting device consists of a primary tubular demister 6 and a two-stage ridge demister 7. The auxiliary flushing device 8 is connected to the process water system 9 via a pipeline. The pipeline is equipped with pumps and valves. The process water is demineralized water. The alkali storage system includes an alkali tank 10 and a bubbling device 11 located at the bottom of the alkali tank. The bubbling device 11 is connected to the air inlet 12120 via a pipeline. The side wall of the alkali tank is connected to the bottom of the circulating slurry pool 3 via a pipeline. The pipeline is equipped with regulating valves. The oxidation system (for reducing the COD of discharged wastewater) includes an oxidation tank 12 and an air duct network 13 located at the bottom of the oxidation tank. The air duct network 13 is connected to the outlet of a blower 14 via a pipe. A humidification and cooling device 15 is installed at the inlet of the blower to ensure that the air is saturated before entering the blower, effectively preventing scaling at the outlet of the air duct network. The outlet of the oxidation tank 12 is connected to a slurry discharge pump 16 via a pipe. The top of the circulating slurry tank 3 is connected to the top of the oxidation tank 12 via a pipe. A regulating valve is installed on the pipe. The opening and closing of the regulating valve between the circulating slurry tank 3 and the oxidation tank 12 is controlled by monitoring the slurry density value and absorption effect of the circulating slurry tank 3. The bottom of the circulating slurry tank 3 is connected to the inlet of four circulating pumps 17 of the slurry recirculation system via pipes. The outlets of the four circulating pumps are connected to four spray layers 5 via pipes. The spray layer 5 consists of a distribution pipe and spiral nozzles installed on the distribution pipe. The spiral nozzles face the bottom of the absorption tower. The spray layer 5 ensures spray coverage by evenly distributing the sprayed slurry. The flue gas inlet 19 is located on the side wall of the absorption tower 1, between the rectifier layer 4 and the circulating slurry tank 3. The top outlet of the absorption tower 1 is connected to the chimney 18 via a pipe. The system is connected to the slurry tank 3 inside the absorption tower 1, which is used to purify the emission of flue gas. A pH measuring device is installed in the circulating slurry tank 3 to detect the pH value of the slurry in the circulating slurry tank 3. When the pH value is lower than 5.0, it will aggravate the corrosion of equipment, especially the pump impeller, and reduce its service life. When the pH value is lower than 8.0, the main product is NaHSO3. When the pH value is higher than 8.0, the main product is Na2SO3. The pH value of the slurry should be controlled between 6 and 9. The pH value in the slurry tank of the absorption tower is controlled by adjusting the injection amount of alkali solution.

[0021] The specific process of removing the main acidic gases SO2 and SO3 from flue gas in the flue gas desulfurization system of this utility model is as follows: The alkali tank 10 is filled with NaOH solution, the concentration of which is controlled at 10 wt% to 18 wt%. The alkali solution is pumped into the circulating slurry tank 3 by a pump. The flow rate of the alkali solution is adjusted by a regulating valve. The flue gas enters the absorption tower 1 through the flue gas inlet 19. The circulating pump 17 sends the alkali solution in the circulating slurry tank 3 to the nozzles of the spray layer 5 inside the absorption tower 1. The slurry is sprayed out through the nozzles, and the flue gas and NaOH slurry come into countercurrent contact. The main acidic gases SO2 and SO3 in the flue gas react with the nitrogen in the slurry. The sodium sulfite and sodium bisulfite react with NaOH to form sodium sulfite and sodium bisulfite. Trace amounts of acidic gases HCl and HF in the flue gas react with NaOH to form water-soluble NaCl and NaF, respectively. The resulting wastewater is discharged into oxidation tank 12. Air blown in by fan 14 is injected into the bottom of oxidation tank 12 through air duct 13, oxidizing the sodium sulfite and sodium bisulfite into sodium sulfate. Finally, the sodium sulfate is transported to the wastewater treatment workshop by slurry discharge pump 16. The desulfurized flue gas, carrying droplets, flows towards the top of absorption tower 1 and is collected by the demister in absorption tower 1, ensuring that the droplet content of the clean flue gas does not exceed 75 mg / m³. 3 (Wet basis, standard state, 3% O2), the clean flue gas enters the chimney 18 through the top flue and is discharged into the atmosphere; when the pressure drop of the demister layer approaches or reaches 150Pa, the demineralized water of the process water system 9 is used to flush the demister. The flushing water pressure of the demister is 200kPa, which removes the main acidic gases SO2 and SO3 in the flue gas.

[0022] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of the present utility model, and these all fall within the protection scope of the present utility model.

Claims

1. A flue gas desulfurization system, characterized in that, The system includes a sulfur dioxide absorption system, an alkali storage system, an oxidation system, and a process water system. The sulfur dioxide absorption system comprises an absorption tower and a slurry recirculation system. Inside the absorption tower, from bottom to top, are a circulating slurry tank, a rectifying layer, a spray layer, a demister, and an auxiliary flushing device. The demister consists of a single-stage tubular demister and a two-stage ridge demister. The auxiliary flushing device is connected to the process water system via a pipeline. The alkali storage system includes an alkali tank and a bubbling device located at the bottom of the tank. The bubbling device is connected to the air inlet via a pipeline. The sidewall of the alkali tank is connected to the bottom of the circulating slurry tank via a pipeline. The pipeline is equipped with… It has a regulating valve; the oxidation system includes an oxidation tank and an air duct network located at the bottom of the oxidation tank. The air duct network is connected to the outlet of the blower through a pipe. A humidification and cooling device is installed at the inlet of the blower. The outlet of the oxidation tank is connected to the slurry discharge pump through a pipe. The top of the circulating slurry tank is connected to the top of the oxidation tank through a pipe. The bottom of the circulating slurry tank is connected to the inlet of the slurry recirculation system through a pipe. The outlet of the slurry recirculation system is connected to the spray layer through a pipe. The flue gas inlet is located on the side wall of the absorption tower, between the rectifier layer and the circulating slurry tank. The top outlet of the absorption tower is connected to the chimney through a pipe.

2. The flue gas desulfurization system according to claim 1, characterized in that, The spray layer consists of a distribution pipe and spiral nozzles installed on the distribution pipe, with the spiral nozzles facing the bottom of the absorption tower.

3. The flue gas desulfurization system according to claim 1, characterized in that, A regulating valve is installed on the pipe between the top of the circulating slurry tank and the top of the oxidation tank.

4. The flue gas desulfurization system according to claim 1, characterized in that, The rectifier layer has 1 to 5 layers and is a pipe grid structure; the slurry recirculation system includes 2 to 6 circulation pumps, and the spray layer has 2 to 6 layers.

5. The flue gas desulfurization system according to claim 1, characterized in that, The absorption tower is cylindrical in shape.

6. The flue gas desulfurization system according to claim 1, characterized in that, Pumps and valves are installed in the pipeline between the auxiliary flushing device and the process water system.

7. The flue gas desulfurization system according to claim 1, characterized in that, A pH measuring device is installed in the circulating slurry tank inside the absorption tower.

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