Device for removing SO2 in flue gas

Abstract

The utility model relates to the technical field of flue gas desulfurization, and provides a device for removing SO2 in flue gas, which comprises a heat exchange area, an absorption area and an electrolysis area, the heat exchange area comprises a plate heat exchanger, the plate heat exchanger is communicated with a flue gas inlet channel, the top of the absorption area is provided with a gas outlet I, and the absorption area is provided with an alkali liquor collecting layer, a spraying layer and a Pall ring packing layer from top to bottom; the electrolysis area is located at the bottom of the absorption area and is communicated with the absorption area through a liquid outlet, the electrolysis area comprises an anode electrolysis chamber and a cathode electrolysis chamber, the anode electrolysis chamber is communicated with the plate heat exchanger through a water pump, and the cathode electrolysis chamber is provided with a second air outlet; the plate heat exchanger is communicated with the absorption area through a liquid inlet and a low-temperature gas inlet, and the plate heat exchanger is also communicated with a sulfuric acid collector. The device disclosed by the utility model has the beneficial effects that the device can be suitable for a method for improving the solubility of SO2 by utilizing an alcohol auxiliary agent, and the effects of efficiently removing SO2 in flue gas and synchronously preparing sulfuric acid and hydrogen are realized.

Description

Technical Field

[0001] This utility model relates to the technical field of flue gas desulfurization, specifically to a device for removing SO2 from flue gas. Background Technology

[0002] In many domestic industries producing sulfuric acid from SO2, the contact oxidation process is the main method, applied to flue gas with a large gaseous component. Vanadium catalysts are commonly used. The principle is to produce SO2-containing flue gas from sulfur-containing raw materials, where SO2 is oxidized to sulfur trioxide gas. The sulfur trioxide generated after conversion is then absorbed by water in the liquid phase to produce sulfuric acid. A typical "two-conversion, two-absorption" method is commonly used for sulfuric acid production, suitable for flue gas with SO2 concentrations greater than 5%, with a maximum SO2 concentration reaching 12.5%. This atmospheric SO2 conversion must be carried out at high temperatures, and most of it requires the intervention of a catalyst, making it unsuitable for the comprehensive treatment of low-temperature flue gas. Several large copper smelting enterprises in China use ionic liquid methods and hydrogen peroxide methods for desulfurization and sulfur production. Comparing these two flue gas desulfurization and sulfuric acid production technologies, the ionic liquid method requires processing in a low-pressure steam environment, limiting its applicability, while the transportation and storage of hydrogen peroxide pose certain safety hazards.

[0003] Therefore, an idea is proposed to use an alcohol auxiliary. The addition of ethanol can promote the decomposition of SO2 in water through hydrogen bonding with water and SO2 molecules. Utilizing the theory that SO2 aqueous solutions have a low decomposition voltage, i.e., bypassing the OER reaction by using the SO2OR reaction, the dissolved SO2 in water is treated, causing hydrogen evolution reaction to occur at the cathode, while the anode is used to treat SO3. 2- The oxidation process replaces OER to lower the potential for hydrogen production through water electrolysis, without producing useless O2. It directly utilizes oxidation to produce SO2, achieving the simultaneous production of sulfuric acid and hydrogen. Utility Model Content

[0004] This invention proposes a device for removing SO2 from flue gas, which is applicable to the method of using alcohol additives to increase the solubility of SO2, thereby achieving efficient removal of SO2 from flue gas and simultaneous production of sulfuric acid and hydrogen.

[0005] Therefore, the technical solution adopted is as follows:

[0006] An apparatus for removing SO2 from flue gas includes a heat exchange zone, an absorption zone, and an electrolysis zone. The heat exchange zone includes a plate heat exchanger connected to a flue gas inlet channel. The absorption zone has an outlet at the top and is provided with an alkaline solution collection layer, a spray layer, and a Pall ring packing layer from top to bottom. The spray layer is connected to a solution inlet. The electrolysis zone is located at the bottom of the absorption zone and is connected to the absorption zone through a liquid outlet. The electrolysis zone includes an anode electrolysis chamber and a cathode electrolysis chamber. The anode electrolysis chamber is connected to the plate heat exchanger via a water pump. The cathode electrolysis chamber has a second outlet. The plate heat exchanger is connected to the absorption zone through a liquid inlet and a low-temperature gas inlet.

[0007] A further technical solution is that the plate heat exchanger is also connected to a sulfuric acid collector.

[0008] A further technical solution is that a guide plate is fixed to the side wall of the absorption zone to guide the solution into the outlet.

[0009] A further technical solution is that the spray layer includes a plurality of spiral sprayers, which are fixed to the inner wall of the absorption zone by a bracket.

[0010] A further technical solution is that a demisting device is fixed at one of the air outlets.

[0011] A further technical solution is that an observation port is provided on the side wall of the absorption region.

[0012] The working principle and beneficial effects of this application are as follows:

[0013] A device for removing SO2 from flue gas is proposed. Through a heat exchange zone, an absorption zone, and an electrolysis zone, SO2 can be synergistically absorbed using a water-ethanol liquid phase system. After heat exchange, SO2 is electrochemically oxidized to simultaneously produce sulfuric acid and hydrogen, thus achieving pollutant purification and resource utilization simultaneously. The desulfurization scheme adapted to this device can not only significantly reduce the use of chemical reagents such as sodium alkali, but also achieve clean and energy-saving effects. Moreover, it is easy to operate and has a simple process, making it very suitable for large-scale industrial applications. Attached Figure Description

[0014] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0015] Figure 1 This is a schematic diagram of the structure of this application.

[0016] In the diagram: 1. Plate heat exchanger; 11. Flue gas inlet channel; 21. Outlet 1; 22. Alkali collection layer; 23. Spray layer; 231. Solution inlet; 24. Pall ring packing layer; 25. Liquid inlet; 26. Low-temperature gas inlet; 27. Baffle plate; 28. Demisting device; 29. ​​Observation port; 30. Liquid outlet; 31. Anode electrolysis chamber; 32. Cathode electrolysis chamber; 321. Outlet 2; 4. Water pump; 5. Sulfuric acid collector. Detailed Implementation

[0017] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this utility model.

[0018] like Figure 1 As shown, a device for removing SO2 from flue gas includes a heat exchange zone, an absorption zone, and an electrolysis zone. The heat exchange zone includes a plate heat exchanger 1, which is connected to a flue gas inlet channel 11. The absorption zone has an outlet 21 at the top and is provided with an alkaline solution collection layer 22, a spray layer 23, and a Pall ring packing layer 24 from top to bottom. The spray layer 23 is connected to a solution inlet 231. The electrolysis zone is located at the bottom of the absorption zone and is connected to the absorption zone through a liquid outlet 30. The electrolysis zone includes an anode electrolysis chamber 31 and a cathode electrolysis chamber 32. The anode electrolysis chamber 31 is connected to the plate heat exchanger 1 through a water pump 4. The cathode electrolysis chamber 32 has an outlet 321. The plate heat exchanger 1 is connected to the absorption zone through a liquid inlet 25 and a low-temperature gas inlet 26. The plate heat exchanger 1 is also connected to a sulfuric acid collector 5.

[0019] The heat exchange zone, absorption zone, and electrolysis zone are connected to sensors and actuators of various devices by a control system, which monitors parameters such as water pump flow rate, temperature, pH value, flue gas flow rate, and flue gas composition in real time. Based on preset parameter values, the control system automatically adjusts the operating status of the equipment to ensure the stable and efficient operation of the entire device. An observation port 29 is provided on the side wall of the absorption zone.

[0020] The desulfurization process of this device is as follows: high-temperature flue gas containing SO2 is introduced into plate heat exchanger 1 through flue gas inlet channel 11. At the same time, low-temperature liquid containing a mixed solution of water, ethanol and sulfuric acid in anode electrolysis chamber 31 is introduced into plate heat exchanger 1 by water pump 4. The high-temperature gas and low-temperature liquid exchange heat in plate heat exchanger 1. After the exchange, the high-temperature gas is converted into low-temperature SO2 and enters the absorption zone through low-temperature gas inlet 26. Meanwhile, the low-temperature liquid introduced into anode electrolysis chamber 31 absorbs heat and is converted into high-temperature water, ethanol and SO2 and enters the absorption zone through liquid inlet 25. At the same time, sulfuric acid is produced and introduced into sulfuric acid collector 5.

[0021] At this time, the spray layer 23 at the top of the absorption zone is sprayed with water and ethanol solution through the solution inlet 231. The absorption zone is shaped like an absorption tower, with a Pall ring packing layer 24 with high porosity in the middle to increase the gas-liquid contact area and improve mass transfer efficiency. The low-temperature SO2 gas entering the absorption zone from the heat exchange zone, as well as the high-temperature SO2 gas, water vapor and ethanol gas after heat exchange, rise upward through the middle Pall ring packing layer 24 and are fully mixed with the water and ethanol solution. After absorption, a mixed solution is formed. A guide plate 27 is fixed on the side wall of the absorption zone to guide the solution into the outlet 30. The mixed solution flows through the guide plate 27 to the lower outlet 30, and is then detected by the pH detector. When the set value is reached, the controller sends a signal to open the valve of the outlet 30 and flow into the electrolysis zone. The unabsorbed flue gas moves upward and is absorbed by the alkaline solution collection layer 22. A demisting device 28 is fixed at the outlet 21. The flue gas finally passes through the demisting device 28 and is discharged into the atmosphere through the outlet 21.

[0022] In the mixed solution entering the electrolysis zone, the mixture of water, ethanol and SO2 passes through the anode electrolysis chamber 31 and is oxidized into sulfuric acid by the high-efficiency anode material under the action of the power supply. The mixed solution of water, ethanol and sulfurous acid is then pumped back into the heat exchange zone to circulate and do work. Meanwhile, the cathode reduces water to produce hydrogen gas, which is discharged through the outlet 321.

[0023] Through the heat exchange zone, absorption zone, and electrolysis zone of this device, SO2 can be absorbed synergistically using a water-ethanol liquid phase system. After heat exchange, SO2 is then electrochemically oxidized to simultaneously produce sulfuric acid and hydrogen, thus achieving pollutant purification and resource utilization. The desulfurization scheme adapted to this device can not only significantly reduce the use of chemical reagents such as sodium alkali, but also achieve clean and energy-saving effects. Moreover, it is easy to operate and has a simple process, making it very suitable for large-scale industrial applications.

[0024] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. An apparatus for removing SO2 from flue gas, characterized in that: The system includes a heat exchange zone, an absorption zone, and an electrolysis zone. The heat exchange zone includes a plate heat exchanger (1), which is connected to a flue gas inlet channel (11). The absorption zone has an outlet (21) at the top and is provided with an alkali collection layer (22), a spray layer (23), and a Pall ring packing layer (24) from top to bottom. The spray layer (23) is connected to a solution inlet (231). The electrolysis zone is located at the bottom of the absorption zone and is connected to the absorption zone through a liquid outlet (30). The electrolysis zone includes an anode electrolysis chamber (31) and a cathode electrolysis chamber (32). The anode electrolysis chamber (31) is connected to the plate heat exchanger (1) through a water pump (4). The cathode electrolysis chamber (32) has an outlet (321). The plate heat exchanger (1) is connected to the absorption zone through a liquid inlet (25) and a low-temperature gas inlet (26).

2. The apparatus for removing SO2 from flue gas according to claim 1, characterized in that, The plate heat exchanger (1) is also connected to a sulfuric acid collector (5).

3. The apparatus for removing SO2 from flue gas according to claim 1, characterized in that, The sidewall of the absorption zone is fixed with a guide plate (27) that guides the solution into the outlet (30).

4. The apparatus for removing SO2 from flue gas according to claim 1, characterized in that, The spray layer (23) includes several spiral sprayers, which are fixed to the inner wall of the absorption zone by a bracket.

5. The apparatus for removing SO2 from flue gas according to claim 1, characterized in that, A de-misting device (28) is fixed at the air outlet (21).

6. The apparatus for removing SO2 from flue gas according to claim 1, characterized in that, An observation port (29) is provided on the side wall of the absorption zone.

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