Silver nitrate tail gas treatment system

Abstract

The present invention relates to the technical field of tail gas treatment, and in particular to a silver nitrate tail gas treatment system, comprising a mixing and pressurizing device, wherein the mixing and pressurizing device comprises a mixing bin, an air inlet of the mixing bin is provided with a tail gas pipe and an oxygen supply pipe, a pressurizing device is provided inside the mixing bin, a plurality of outlet pipes are provided on the side of the mixing bin, a heating device is provided in the conveying direction of the outlet pipe, an output end of the heating device is connected with a treatment tank for adsorbing nitrogen dioxide, so as to avoid direct discharge causing harm to the environment, the system has a simple structure, is easy to operate, has high treatment efficiency, and is suitable for use in industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of tail gas treatment, and in particular to a silver nitrate tail gas treatment system. Background Art

[0002] Silver nitrate is a colorless crystal. It is commonly used in photographic emulsions, silver plating, mirror making, printing, medicine, hair dyeing, and testing of chloride ions, bromide ions and iodine ions. It is also used in the electronics industry. Silver nitrate is generally produced by reacting silver with nitric acid. The tail gas produced during the production of silver nitrate is mainly composed of NO and NO2, which are harmful gases to the human body and are important atmospheric pollutants. Therefore, the tail gas produced during the production process needs to be treated to avoid direct emissions that cause harm to the environment.

[0003] In order to improve the treatment effect during the treatment process, NO is sometimes converted into NO2. However, it is known that the reaction of NO and O2 requires high temperature. Under atmospheric pressure, the reaction rate is very slow, but under high pressure, the reaction rate will increase. Although this reaction is a spontaneous reaction and does not require a catalyst to accelerate the reaction rate, in the industrial production process, the use of catalysts can accelerate the reaction rate and promote the selective catalytic reduction of nitrogen oxides at lower temperatures. The equipment used in the commonly used nitrogen oxide treatment technology is large and costly, which is not suitable for the exhaust gas treatment of industrial production of silver nitrate, and generally has problems such as low purification efficiency. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art that the tail gas treatment equipment in the production of silver nitrate is bulky and has low purification efficiency, and to provide a silver nitrate tail gas treatment system.

[0005] In order to achieve the above-mentioned purpose, the embodiment of the present invention specifically adopts the following technical scheme: a silver nitrate tail gas treatment system, including a mixing and pressurizing device, the mixing and pressurizing device includes a mixing bin, the air inlet of the mixing bin is provided with a tail gas pipe and an oxygen supply pipe, the interior of the mixing bin is provided with a pressurizing device, the side of the mixing bin is provided with a plurality of outlet pipes, a heating device is provided in the conveying direction of the outlet pipes, and the output end of the heating device is connected to a treatment tank for adsorbing nitrogen dioxide.

[0006] Furthermore, the mixing bin is cylindrical, an upper end cover is provided at the top of the mixing bin and a lower end cover is provided at the bottom, the pressurizing device includes a lower piston provided at a middle position of the lower end cover, and an upper piston is slidably provided at the top of the mixing bin.

[0007] Furthermore, a sleeve is provided on the upper part of the upper end cover, a sliding rod is provided inside the sleeve, the lower part of the sliding rod passes through the upper end cover and is connected with the upper piston, a spring is wound around the outside of the sleeve, a sliding groove is vertically provided on the outer wall of the sleeve, a blocking rod is provided on the side wall of the sliding rod, and the sliding groove abuts against the bottom of the spring, and an adjusting nut is provided on the upper part of the sleeve.

[0008] Furthermore, two layers of diamond mesh are arranged on the inner wall of the mixing bin, and a catalyst is arranged between the two layers of diamond mesh.

[0009] Furthermore, the air inlet of the air outlet pipe is arranged on the side of the mixing chamber, the bottom dead point of the upper piston is lower than the air inlet, and the top dead point of the upper piston is higher than the air inlet.

[0010] Furthermore, a connector is provided at the connection between the air outlet pipe and the mixing chamber, the air outlet pipe is a coil arranged upward, and a support plate for connection is provided between the air outlet pipes.

[0011] Furthermore, the temperature increasing device comprises a heat source arranged below the air outlet pipe, the support plate is made of heat conductive material, and a reinforcing pipe for protection is sleeved on the outer side of the initial section of the air outlet pipe.

[0012] Furthermore, at least three outlet pipes are provided, and an air distribution plate is provided at the outlet end of the outlet pipe inside the processing tank, a spraying device for spraying alkali solution is provided on the upper part of the processing tank, and an exhaust pipe is provided on the side wall of the processing tank.

[0013] Furthermore, the gas distributor is conical, the middle position of the gas distributor is rotatably set on the inner wall of the processing tank, the installation direction of the gas distributor is inclined toward the central axis of the processing tank, and the working surface of the gas distributor is provided with multiple nozzles to drive the gas distributor to rotate.

[0014] Furthermore, the spraying device includes a first-level spraying pipe arranged above the gas distribution plate, a delivery pipe connected to the alkali solution storage tank is arranged in the middle position of the first-level spraying pipe, the first-level spraying pipe is rotatably arranged on the delivery pipe, a partition is arranged above the first-level spraying pipe, a plurality of holes are arranged on the partition, and a second-level spraying pipe is arranged above the partition.

[0015] The beneficial effects of the embodiments of the present invention are as follows: the reaction environment of NO and O2 inside the mixing chamber is a high-pressure and catalyst-containing environment, and by heating the initial section of the outlet pipe, the reaction of NO and O2 is accelerated during the transportation of the mixed gas inside the outlet pipe, and the NO that has not reacted completely inside the mixing chamber is further reacted, greatly accelerating the reaction rate of NO and O2.

[0016] The NO2 in the mixed gas is fully absorbed by the primary spray pipe and the secondary spray pipe, so that the alkali solution and NO2 fully react, and the tail gas containing NO and NO2 generated in the production process of silver nitrate is effectively treated to avoid direct discharge and harm to the environment. The system has a simple structure, easy operation and high processing efficiency, and is suitable for use in industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0018] Figure 2 It is a schematic diagram of the overall cross-sectional structure of the present invention;

[0019] Figure 3 It is a schematic diagram of the internal structure of the mixing bin of the present invention;

[0020] Figure 4 It is a schematic diagram of the enlarged structure of point A of the present invention;

[0021] Figure 5 It is a schematic diagram of the internal structure of the processing tank of the present invention;

[0022] Figure 6 It is a structural schematic diagram of the first-level spray pipe of the present invention;

[0023] In the figure: 1. mixing chamber; 101. tail gas pipe; 102. oxygen supply pipe; 2. upper end cover; 201. upper piston; 202. sliding rod; 2021. stop rod; 203. sleeve; 2031. slide groove; 204. spring; 3. lower end cover; 301. lower piston; 302. diamond mesh; 4. outlet pipe; 401. reinforcement pipe; 402. support plate; 403. heat source; 5. treatment tank; 501. gas distribution plate; 502. exhaust pipe; 503. partition; 6. delivery pipe; 601. primary spray pipe; 602. secondary spray pipe; 603. branch pipe. DETAILED DESCRIPTION

[0024] Preferred embodiments of the present invention are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0025] See also Figures 1 to 6 The embodiment of the present invention discloses a silver nitrate tail gas treatment system, which mainly includes a mixing and pressurizing device, a heating device and a treatment tank 5 for adsorbing nitrogen dioxide. The tail gas generated in mass production on the production line is filtered through graded treatment, and the internal nitric oxide is converted into nitrogen dioxide for treatment and absorption, thereby increasing the treatment capacity, ensuring that the tail gas emissions in the entire production meet the standards, and improving the treatment effect.

[0026] The filtered tail gas first enters the mixing and pressurizing device, which includes a mixing chamber 1. The air inlet of the mixing chamber 1 is provided with a tail gas pipe 101 and an oxygen supply pipe 102 for mixing the tail gas with oxygen. The oxygen supply pipe 102 supplies compressed air, and the oxygen in the compressed air is combined with nitric oxide to reduce the production cost. At the same time, a one-way valve is arranged on the tail gas pipe 101 and the oxygen supply pipe 102 to prevent backflow during the pressurization process and ensure the use effect. A pressurizing device is arranged inside the mixing chamber 1 to increase the reaction rate of the tail gas and oxygen. The mixing chamber 1 is cylindrical and adopts a thickened setting. To ensure the pressure-bearing effect, an upper end cover 2 is provided on the upper part of the mixing chamber 1, and a lower end cover 3 is provided on the lower part. The pressurizing device includes a lower piston 301 arranged in the middle position of the lower end cover 3, and an upper piston 201 is slidably provided on the upper part of the mixing chamber 1. The bottom of the lower piston 301 is connected to a hydraulic cylinder or a motor connecting rod structure for driving, and the lower piston 301 is driven to move up and down to increase the pressure of the mixed gas by compressing the space between the upper piston 201 and the lower piston 301, wherein the upper dead point of the lower piston 301 is below the inlet of the exhaust pipe 101 and the oxygen supply pipe 102, so that the lower piston 301 can replenish air during the downward process, thereby reducing the air supply time.

[0027] A sleeve 203 is fixedly provided on the top of the upper end cover 2, a slide rod 202 is slidably provided inside the sleeve 203, the lower part of the slide rod 202 passes through the upper end cover 2 and is connected to the upper piston 201, a spring 204 is wound around the outside of the sleeve 203 to provide a reset force for the upper piston 201, a slide groove 2031 is vertically provided on the outer wall of the sleeve 203, a stopper rod 2021 is provided on the side wall of the slide rod 202 to protrude from the slide groove 2031 and abut against the bottom of the spring 204 to limit the travel of the slide rod 202, and the sleeve An adjusting nut is arranged on the upper part of the tube 203 for adjusting the compression degree of the spring 204, and then the driving pressure when the upper piston 201 is squeezed by the lower gas can be adjusted by adjusting the tightening degree of the nut, thereby improving the use effect. A plurality of air outlet pipes 4 are arranged on the side of the mixing chamber 1 for conveying the mixed gas to the heating device, and the air inlet of the air outlet pipe 4 is arranged on the side of the mixing chamber 1, the lower dead point of the upper piston 201 is lower than the air inlet, and the upper dead point of the upper piston 201 is higher than the air inlet. When the upper piston 201 moves to the lower dead center, the upper surface of the upper piston 201 is higher than the air inlet, and the side of the upper piston 201 is sealed to prevent the mixed gas from entering the air outlet pipe 4 from flowing back, ensuring that the mixed gas can smoothly enter the air outlet pipe 4 when the upper piston 201 moves up and down, ensuring the use effect. When in use, the lower piston 301 moves upward to compress the internal space of the mixing chamber 1. As the internal pressure of the mixing chamber 1 increases, the upper piston 201 will move upward, thereby exposing the air inlet of the air outlet pipe 4, and the mixed gas enters the interior of the air outlet pipe 4. After part of the mixed gas is discharged, the upper piston 201 moves downward to block the air inlet of the air outlet pipe 4 when the lower piston 301 moves downward. At this time, the tail pipe 101 and the oxygen supply pipe 102 continue to supply gas to ensure the positive pressure inside the mixing chamber 1, so that the entire gas supply and compression process is continuous, and the number of different mixing chambers 1 can be selected according to the amount of tail gas generated in actual production, so that the gas entering the air outlet pipe 4 is continuous multi-pulse gas, thereby ensuring the continuity of production and improving processing efficiency.

[0028] Two layers of diamond mesh 302 are arranged on the inner wall of the mixing chamber 1, and a catalyst is arranged between the two layers of diamond mesh 302. The catalyst is selected from metal oxides such as Mn-, Co-, Cr-, and Ce-based. Such catalysts have the characteristics of high activity and low cost, so that the reaction environment of NO and O2 inside the mixing chamber 1 is a high-pressure and catalytic environment, which greatly accelerates the reaction rate of NO and O2.

[0029] A heating device is arranged in the conveying direction of the outlet pipe 4, and is used to increase the temperature of the mixed gas, so as to accelerate the reaction of NO and O2 to generate NO2. A connector is arranged at the connection between the outlet pipe 4 and the mixing chamber 1. The outlet pipe 4 is a coil arranged upward to increase the heating time of the gas. A support plate 402 for connection is arranged between the outlet pipes 4. The support plate 402 is made of heat-conducting material to improve the heating efficiency. A heat source 403 below the outlet pipe 4 is used to provide the heat required for heating. The heat source 403 uses natural gas as fuel and is arranged below the support plate 402. The bottom of the support plate 402 is directly burned by the flame. A reinforcing pipe 401 for protection is arranged on the outside of the initial section of the outlet pipe 4 to prevent the outlet pipe 4 from being damaged by high temperature. When in use, the support plate 402 strengthens and fixes the multi-layer outlet pipe 4 and provides a relatively high temperature conveying process for the outlet pipe 4, which enters the mixing chamber 1. At the moment of entering and exiting the air pipe 4 at the initial section, the mixed gas still has a relatively high pressure. By heating the initial section of the air outlet pipe 4, the reaction of NO and O2 is accelerated during the transportation of the mixed gas inside the air outlet pipe 4, and the NO that has not reacted completely in the mixing chamber 1 is further reacted. The upper temperature of the air outlet pipe 4 is lower than the temperature of the lower part. The subsequent cooling process makes the mixed gas gradually tend to be stable, ensuring that the mixed gas entering the treatment tank 5 tends to be stable. In order to improve the use effect, multiple mixing chambers 1 can share a heating device. By pressurizing, catalyzing and heating the tail gas generated in the production process, NO and O2 are prompted to react more, so that most of the NO in the mixed gas is converted into NO2. Compared with the treatment method in the prior art, the NO content is greatly reduced, making the treatment effect more thorough and suitable for large-scale industrial production.

[0030] The output end of the heating device is connected to a treatment tank 5 for absorbing nitrogen dioxide. The treatment tank 5 is used to absorb the generated NO2 to prevent it from being discharged into the atmosphere. The outlet pipe 4 is provided with at least three outlets. The outlet end of each outlet pipe 4 is provided with a gas distribution plate 501 inside the treatment tank 5 for evenly distributing the gas into the treatment tank 5. The occipital bone of the gas distribution plate 501 is conical, and the middle position is rotatably arranged on the inner wall of the treatment tank 5. The installation direction of the gas distribution plate 501 is inclined toward the central axis direction of the treatment tank 5. A plurality of nozzles for driving the gas distribution plate 501 to rotate are provided on the working surface, so that when the gas distribution plate 501 sprays the mixed gas, it can drive the gas distribution plate 501 to rotate as a whole, The gas distribution plates 501 cooperate with each other and impact and collide inside the treatment tank 5, which can ensure that the gas is evenly distributed in the treatment tank 5 and improve the treatment efficiency. The spraying device includes a first-level spraying pipe 601 arranged above the gas distribution plate 501, and a delivery pipe 6 connected to the alkali solution storage tank is arranged in the middle position of the first-level spraying pipe 601. The first-level spraying pipe 601 includes a plurality of branch pipes and is rotatably arranged on the delivery pipe 6. The branch pipes can adjust the spraying angle as needed. According to different spraying angles, the first-level spraying pipe 601 can rotate during the process of spraying the alkali solution, so that the alkali solution can be more fully in contact with NO2 in the mixed gas, which greatly improves the absorption efficiency of NO2 and ensures the treatment effect.

[0031] A partition 503 is arranged above the primary spray pipe 601, and a plurality of holes are arranged on the partition 503. The holes on the partition 503 have a smaller diameter. A secondary spray pipe 602 is arranged above the partition 503. Due to the continuous delivery of the mixed gas at the bottom, the mixed gas in the treatment tank 5 will flow upward through the holes on the partition 503, and the alkali solution above the partition 503 will flow downward from the holes. The rotating primary spray pipe 601 will break up the flowing alkali solution to increase the contact area. However, due to the smaller diameter of the holes on the partition 503, the alkali solution sprayed from the secondary spray pipe 602 will gather above the partition 503 to form a solution layer. The spraying and downward flow of the solution layer reach a relative balance. A liquid level sensor is installed above the partition 503 to prevent the alkali solution from being too high. During use, the liquid level at the bottom of the treatment tank 5 The mixed gas is first processed by the first-level spray pipe 601 to absorb most of the NO2 therein. Due to the action of the upper piston 201 and the lower piston 301 in the mixing chamber 1, the pressure of the mixed gas at the bottom will form a frequency vibration pulse as the pressurization process occurs, forming a vibration mixing effect, resulting in a vibration effect when the mixed gas rises through the partition 503, thereby preventing a large amount of accumulation of the solution layer. At the same time, the mixed gas passing through the partition 503 contacts the solution layer and the second-level spray pipe 602 above, and the remaining NO2 in the mixed gas is fully absorbed, so that the alkali solution and NO2 fully react, and the tail gas containing NO and NO2 generated in the silver nitrate production process is effectively treated to avoid direct emissions causing harm to the environment. The system has a simple structure, is easy to operate, and has a high processing efficiency, and is suitable for use in industrial production.

[0032] An exhaust pipe 502 is provided on the side wall of the treatment tank 5 for discharging the treated gas. The exhaust pipe 502 is arranged to be inclined upward, and a filter is installed at the inlet of the exhaust pipe 502. A branch pipe 603 is provided from the delivery pipe 6, and a nozzle is installed on the branch pipe 603 to flush the filter, thereby improving the treatment effect of NO2 and improving the absorption degree.

[0033] It should be noted that in the description of the present invention, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0034] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] The term "comprise" or any other similar term is intended to cover a non-exclusive inclusion, such that a process, article, or apparatus / device that includes a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, article, or apparatus / device.

[0036] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A silver nitrate tail gas treatment system, characterized in that: It includes a mixing and pressurizing device, which includes a mixing chamber, an air inlet of the mixing chamber is provided with a tail gas pipe and an oxygen supply pipe, a pressurizing device is provided inside the mixing chamber, a plurality of air outlet pipes are provided on the side of the mixing chamber, a heating device is provided in the conveying direction of the air outlet pipes, and an output end of the heating device is connected to a treatment tank for adsorbing nitrogen dioxide.

2. The silver nitrate tail gas treatment system according to claim 1, characterized in that: The mixing bin is cylindrical, an upper end cover is arranged at the top of the mixing bin and a lower end cover is arranged at the bottom of the mixing bin, the pressurizing device comprises a lower piston arranged at the middle position of the lower end cover, and an upper piston is slidably arranged at the top of the mixing bin.

3. The silver nitrate tail gas treatment system according to claim 2, characterized in that: A sleeve is provided on the upper part of the upper end cover, a slide rod is provided inside the sleeve, the lower part of the slide rod passes through the upper end cover and is connected with the upper piston, a spring is wound around the outside of the sleeve, a slide groove is vertically provided on the outer wall of the sleeve, a stop rod is provided on the side wall of the slide rod, and the slide groove abuts against the bottom of the spring, and an adjusting nut is provided on the upper part of the sleeve.

4. The silver nitrate tail gas treatment system according to claim 2, characterized in that: Two layers of diamond mesh are arranged on the inner wall of the mixing bin, and a catalyst is arranged between the two layers of diamond mesh.

5. The silver nitrate tail gas treatment system according to claim 2, characterized in that: The air inlet of the air outlet pipe is arranged on the side of the mixing chamber, the bottom dead point of the upper piston is lower than the air inlet, and the top dead point of the upper piston is higher than the air inlet.

6. The silver nitrate tail gas treatment system according to claim 1, characterized in that: A connector is provided at the connection between the air outlet pipe and the mixing chamber. The air outlet pipe is a coil arranged upward. A support plate for connection is provided between the air outlet pipes.

7. The silver nitrate tail gas treatment system according to claim 6, characterized in that: The temperature increasing device comprises a heat source arranged below the air outlet pipe, the support plate is made of heat conductive material, and a reinforcing pipe for protection is sleeved on the outer side of the initial section of the air outlet pipe.

8. The silver nitrate tail gas treatment system according to claim 1, characterized in that: At least three outlet pipes are provided, and an air distribution plate is provided at the outlet end of the outlet pipe inside the processing tank. A spraying device for spraying alkali solution is provided on the upper part of the processing tank, and an exhaust pipe is provided on the side wall of the processing tank.

9. The silver nitrate tail gas treatment system according to claim 8, characterized in that: The gas distributor is conical in shape, and its middle position is rotatably arranged on the inner wall of the processing tank. The installation direction of the gas distributor is inclined toward the central axis of the processing tank, and the working surface of the gas distributor is provided with a plurality of nozzles for driving the gas distributor to rotate.

10. The silver nitrate tail gas treatment system according to claim 8, characterized in that: The spraying device includes a first-level spraying pipe arranged above the gas distribution plate, a delivery pipe connected to the alkali solution storage tank is arranged in the middle position of the first-level spraying pipe, the first-level spraying pipe is rotatably arranged on the delivery pipe, a partition is arranged above the first-level spraying pipe, a plurality of holes are arranged on the partition, and a second-level spraying pipe is arranged above the partition.

Images