An evaluation device for hydrogen chloride catalytic oxidation reaction

Abstract

The application provides an evaluation device for hydrogen chloride catalytic oxidation reaction and relates to the chlor-alkali chemical industry technical field.The evaluation device comprises a nitrogen steel cylinder, a hydrogen chloride steel cylinder and an oxygen steel cylinder, the nitrogen steel cylinder, the hydrogen chloride steel cylinder and the oxygen steel cylinder are communicated to a reaction tube through a first gas conveying pipeline, a second gas conveying pipeline and a third gas conveying pipeline respectively, the first gas conveying pipeline and the second gas conveying pipeline are communicated to form a composite pipeline, switch valves are arranged on the gas conveying pipelines, the composite pipeline and the third gas conveying pipeline are provided with a pressure reducing valve, the pressure reducing valve is located downstream of the switch valves, a mass flow meter is arranged downstream of the pressure reducing valve, a thermocouple sleeve is fused in the reaction tube, a discharge pipeline is communicated to one side of the reaction tube, a sampling pipe and a tail gas absorption device are connected to the discharge pipeline, the composite pipeline is communicated with a venting pipeline for emptying hydrogen chloride in the direction opposite to the gas conveying direction, a venting valve is arranged on the venting pipeline, and two switch valves are arranged on the first gas conveying pipeline.

Description

Technical Field

[0001] This application relates to the field of chlor-alkali chemical technology, and in particular to an evaluation device for the catalytic oxidation reaction of hydrogen chloride. Background Technology

[0002] Currently, the production of chlorine from hydrogen chloride includes electrolysis, direct oxidation, and catalytic oxidation, among which catalytic oxidation with ruthenium-based catalysts has extensive industrial applications. Under the action of a catalyst, hydrogen chloride and oxygen are converted into chlorine and water. This method has the advantages of low reaction temperature and high conversion rate, and is currently the mainstream process for recovering and reproducing chlorine from hydrogen chloride.

[0003] Related technologies can be found in Chinese Utility Model Patent No. CN221124458U. This utility model discloses a catalyst evaluation system, including an inlet unit and a reaction unit. The inlet unit includes an oxygen source, a hydrogen chloride source, and a nitrogen source, each connected to a gas pipeline. Each gas pipeline is divided into multiple parallel branch pipelines, each equipped with a branch control valve and a flow controller to individually control the flow rate of the raw material gas. The reaction unit includes multiple reactors. The branch pipelines corresponding to the three raw material gases are grouped and connected to the reactors. Each reactor is independent and can simulate catalysts under different process conditions for evaluation, resulting in high evaluation efficiency and accuracy. A purging pipeline is connected to the gas pipeline corresponding to the nitrogen source. The outlet of the purging pipeline is connected to the gas pipeline corresponding to the hydrogen chloride source. By purging with nitrogen, residual hydrogen chloride in the raw material gas is purged and dried, thereby reducing corrosion to the equipment and protecting and extending the service life of the equipment.

[0004] However, the existing evaluation device still has the following shortcomings. Although a hydrogen chloride purging device is provided, in addition to purging the hydrogen chloride downstream for treatment by the tail gas absorption system, the purging device will also bring the purged mixed gas into the reactor to participate in the reaction. The reaction ratio of the mixed gas is not fixed, and the evaluation device requires extremely high data accuracy for evaluation. Therefore, the mixed gas with an unfixed reaction ratio will affect the accuracy of the reaction data. Utility Model Content

[0005] This application provides an evaluation device for the catalytic oxidation reaction of hydrogen chloride, which solves the problem that the mixed gas formed after purging affects the accuracy of the data.

[0006] The technical solution adopted in the embodiments of this application is as follows: In a first aspect, embodiments of this application provide an evaluation device for the catalytic oxidation reaction of hydrogen chloride, comprising a nitrogen cylinder, a hydrogen chloride cylinder, and an oxygen cylinder. The nitrogen cylinder, hydrogen chloride cylinder, and oxygen cylinder are respectively connected to a reaction tube via a first gas supply pipeline, a second gas supply pipeline, and a third gas supply pipeline. The first gas supply pipeline and the second gas supply pipeline are interconnected to form a composite pipeline. Each gas supply pipeline is equipped with a switching valve. The composite pipeline and the third gas supply pipeline are equipped with pressure reducing valves. The pressure reducing valves are located downstream of the switching valves. A mass flow meter is installed downstream of the pressure reducing valves. A thermocouple sheath is fused inside the reaction tube. A discharge pipeline is connected to one side of the reaction tube. A sampling pipe and a tail gas absorption device are connected to the discharge pipeline. A venting pipeline for venting hydrogen chloride is connected to the composite pipeline in the direction opposite to the gas supply direction. A venting valve is installed on the venting pipeline.

[0007] By adopting the above technical solution, when purging is required, the vent valve of the venting pipeline is opened, and nitrogen gas flows in reverse from the composite pipeline to directly discharge the residual gas in the hydrogen chloride pipeline into the device, without passing through the reaction tube and downstream equipment. This design is based on the principle of gas flow, and by using reverse purging, it avoids hydrogen chloride from entering the reaction area, thereby significantly reducing the risk of corrosion of the catalyst, reaction tube, and sampling system by hydrogen chloride. Furthermore, since the mixed gas does not enter the downstream of the device to participate in the reaction, it ensures the accuracy of the reaction data.

[0008] In one alternative implementation, a premixing tank is provided between the composite pipeline, the third gas transmission pipeline, and the reaction pipe.

[0009] By adopting the above technical solution, the premixing tank acts as a buffer container, utilizing its internal space to allow hydrogen chloride and oxygen to fully diffuse and convect before entering the reaction tube, ensuring the uniformity of the gas composition. This reduces side reactions or incomplete reactions caused by excessively high or low local concentrations, thereby improving the reaction conversion rate.

[0010] In one alternative implementation, a reaction valve is provided at the inlet of the reaction tube.

[0011] By adopting the above technical solution, the reaction valve, acting as a shut-off device, can instantly block gas flow, facilitating the separation of the reaction tube from the upstream pipeline when replacing the catalyst or cleaning the reaction tube. This reduces equipment downtime, thereby improving operational efficiency and reducing the risk of gas leakage.

[0012] In one alternative implementation, the reaction valve is connected to the reaction pipe via a flange.

[0013] By adopting the above technical solution and using flange connections for the reaction valve, the impact of insufficient sealing at the connection and inconvenience in disassembly is reduced. Flange connections provide a high-strength, high-sealing interface capable of withstanding high temperatures and pressure fluctuations during the reaction process, preventing gas leakage, and achieving both guaranteed sealing and convenient disassembly and maintenance.

[0014] In one alternative implementation, the reaction tube is made of quartz.

[0015] By adopting the above technical solution and using quartz material to make the reaction tube, the quartz material has excellent high temperature resistance, corrosion resistance and chemical inertness. It can maintain structural stability under the high temperature conditions of the chlorination-hydrogenation reaction and does not interact with the reactants or products, thus achieving the effect of ensuring the stability of the reaction.

[0016] In one alternative implementation, heat tracing cables can be detachably connected to both sides of the reaction tube.

[0017] By adopting the above technical solution, the heating cable continuously heats the reaction tube and connected pipelines, maintaining the temperature above the dew point of water vapor and hydrogen chloride, reducing the corrosive hydrochloric acid formed by condensate, and achieving the effect of ensuring the uniformity and continuity of heating and reducing the risk of corrosion.

[0018] In one alternative implementation, a three-way valve is provided on the discharge pipeline, with one end of the three-way valve connected to a sampling bottle and the other end connected to a tail gas absorption device.

[0019] By adopting the above technical solution, the three-way valve allows the operator to easily direct the airflow to the sampling bottle or the exhaust gas absorption device without disassembling the pipeline, thus achieving a fast and seamless mode switch.

[0020] In one alternative implementation, the exhaust gas absorption device includes two absorption bottles connected in series, with the pipelines inside each absorption bottle having a longer inlet and a shorter outlet.

[0021] By adopting the above technical solutions, the series design increases the contact time and path between the gas and the absorbent, while the long inlet and short outlet structure utilizes gravity difference and fluid dynamics to allow the gas to remain in the bottle for a sufficient period of time and react with the liquid, thereby improving the efficiency of tail gas absorption.

[0022] In summary, this application includes at least one of the following beneficial technical effects: 1. By setting up venting pipelines and premixing tanks, the corrosive gases are safely isolated and the reaction gases are fully premixed, which significantly reduces the risk of equipment corrosion and ensures uniform and stable reaction conditions, thereby effectively improving the accuracy and reliability of experimental data. 2. By combining a quartz reaction tube with a detachable heat tracing cable, along with a three-way valve switching and series absorption bottle design, the device ensures corrosion resistance and temperature uniformity while achieving efficient switching between sampling and exhaust gas treatment, thus comprehensively improving operational safety and exhaust gas treatment effectiveness. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of an evaluation device for the catalytic oxidation reaction of hydrogen chloride.

[0024] Explanation of reference numerals in the attached diagram: 1. Nitrogen cylinder; 2. Hydrogen chloride cylinder; 3. Oxygen cylinder; 4. First gas delivery pipeline; 5. Second gas delivery pipeline; 6. Third gas delivery pipeline; 7. Composite pipeline; 8. Switch valve; 9. Vent valve; 10. Pressure reducing valve; 11. Mass flow meter; 12. Premixing tank; 13. Reaction valve; 14. Flange; 15. Reaction pipe; 16. Thermocouple sheath; 17. Heating tape; 18. Discharge pipeline; 19. Three-way valve; 20. Sampling bottle; 21. Absorption bottle. Detailed Implementation

[0025] The present application will be further described in detail below with reference to all the accompanying drawings in the embodiments of the present application.

[0026] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. "Fixed connection" refers to a connection where the relative positional relationship remains unchanged after the connection. It should be understood that when component A is fixedly connected to component C via component B, changes in the relative positional relationship due to deformation of components A, B, and C are permissible. The integrated structure obtained by the two components through a one-piece molding process means that during the formation of one of the two components, that component is connected to the other component, without requiring further processing (such as bonding, welding, snap-fit ​​connections, or screw connections) to connect the two components.

[0027] The directional terms mentioned in the embodiments of this application, such as "upper", "lower", "side", etc., are only for reference to the direction of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of this application, and are not intended to 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 the embodiments of this application.

[0028] The term "multiple" refers to at least two. The term "more than" includes the stated number. The term "and / or" describes a relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0029] This application discloses an evaluation device for the catalytic oxidation reaction of hydrogen chloride.

[0030] Reference Figure 1 An evaluation device for the catalytic oxidation reaction of hydrogen chloride includes a nitrogen cylinder 1, a hydrogen chloride cylinder 2, and an oxygen cylinder 3. Each cylinder is connected to a reaction tube 15 via a first gas supply line 4, a second gas supply line 5, and a third gas supply line 6, respectively.

[0031] The first gas supply line 4 and the second gas supply line 5 are interconnected by a pipe joint to form a composite pipeline 7. This parallel structure allows nitrogen to be used as both a purging gas and a balancing gas. All gas supply lines are made of 316L stainless steel and are equipped with manual on / off valves 8.

[0032] The composite pipeline 7 is equipped with a venting pipeline. This venting pipeline is connected to the end of the composite pipeline 7 opposite to the delivery direction, and a dedicated venting valve 9 is installed on the pipeline. Correspondingly, the first gas delivery pipeline 4 is equipped with two switch valves 8. When the two valves are closed, the venting pipeline can be fully opened to discharge the residual gas in the pipeline.

[0033] The venting pipeline extends to an external exhaust gas treatment device. When the venting valve 9 is opened, nitrogen can flow in the reverse direction, directly expelling the residual gas in the hydrogen chloride pipeline from the device, instead of following the gas flow into the downstream of the device to participate in the reaction, thus affecting the accuracy of the reaction data.

[0034] On both the composite pipeline 7 and the third gas supply pipeline 6, downstream of the switching valve 8, pressure reducing valves 10 are installed. These pressure reducing valves 10 can stabilize the high-pressure gas at the cylinder outlet to the pressure required for the experiment. Downstream of the pressure reducing valve 10 is a mass flow meter 11, which controls the gas flow rate by measuring the parameter changes as the gas flows through the sensor.

[0035] A premixing tank 12 is installed between the composite pipeline 7, the third gas supply pipeline 6, and the reaction pipe 15. This premixing tank 12 is made of quartz material, has a suitable volume, and is connected to both the composite pipeline 7 and the third gas supply pipeline 6 on one side. An outlet is located on the upper surface of the tank and is connected to the reaction pipe 15 via a gas supply pipeline. The premixing tank 12 is connected to the inlet of the reaction pipe 15 via a standard flange 14, and a sealing gasket is used at the flange 14 connection to ensure a tight seal. A reaction valve 13 is also installed on the pipeline between the premixing tank 12 and the reaction pipe 15. This valve employs a reliable sealing structure to completely block gas flow. The reaction tube 15 is made of transparent quartz material and has a straight tube structure. Inside the reaction tube 15, a thermocouple sheath 16 is fused together at high temperature. The sheath is made of the same quartz material as the reaction tube 15 and has a thin tube structure. The reaction tube 15 is fixed with a heat tracing tape 17 on both sides by Velcro.

[0036] One end of the reaction tube 15 is connected to the air inlet pipe via flange 14, and the other side of the reaction tube 15 is connected to the discharge pipe 18. The discharge pipe 18 is also made of quartz and is reliably connected to the reaction tube 15 via a polytetrafluoroethylene hose.

[0037] A three-way valve 19 is installed on the discharge line 18. One outlet of the three-way valve 19 is connected to the sampling bottle 20 via a sampling tube, and the other outlet is connected to the tail gas absorption device.

[0038] The exhaust gas absorption device consists of two absorption bottles 21 connected in series. Each absorption bottle 21 includes an inlet pipe and an outlet pipe. The inlet pipe is a long pipe with its end close to the bottom of the bottle, while the outlet pipe is a short pipe that only slightly extends into the bottle stopper. This long-inlet, short-outlet design ensures that the gas remains in the alkaline solution for a sufficient period of time, thus maximizing the absorption of the exhaust gas.

[0039] The implementation principle of the evaluation device for the catalytic oxidation reaction of hydrogen chloride in this application embodiment is as follows: The structural design of the venting pipeline allows the device to directly discharge corrosive hydrogen chloride gas from the system by opening the venting valve 9 and utilizing the reverse flow of nitrogen, reducing the possibility of it entering the reaction tube 15 and downstream equipment, thereby effectively protecting the catalyst and precision components and ensuring the accuracy of the reaction data. The internal structure and volume design of the premixing tank 12 provide sufficient mixing space for the reaction gas, ensuring that the gas composition entering the reaction tube 15 is uniform and reducing the impact of local concentration fluctuations on the reaction results. The quartz reaction tube 15 can not only withstand high-temperature reaction conditions, but its chemical inertness also avoids the interaction between the tube wall and the reactants, ensuring the authenticity of the reaction data. The detachable heating cable 17 structure not only achieves continuous heating of the pipeline to prevent corrosion caused by product condensation, but also facilitates equipment maintenance and replacement. The reasonable arrangement of the three-way valve 19 allows for quick switching between sampling and tail gas treatment modes, reducing the risk of gas leakage and pollution caused by pipeline disassembly. The series absorption bottle 21, combined with the long-in-short-out pipeline design, significantly improves the tail gas absorption efficiency and ensures the environmental safety of the experimental process.

[0040] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other, and any combination of features in different embodiments is also within the protection scope of this application. That is to say, the multiple embodiments described above can also be arbitrarily combined according to actual needs.

[0041] It should be noted that all the above-mentioned figures are exemplary illustrations of this application and do not represent the actual size of the product. Furthermore, the dimensional proportions between the components in the figures are not intended to limit the actual product of this application. The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An evaluation device for the catalytic oxidation reaction of hydrogen chloride, comprising a nitrogen cylinder (1), a hydrogen chloride cylinder (2), and an oxygen cylinder (3), wherein the nitrogen cylinder (1), the hydrogen chloride cylinder (2), and the oxygen cylinder (3) are respectively connected to a reaction tube (15) through a first gas supply line (4), a second gas supply line (5), and a third gas supply line (6), and the first gas supply line (4) and the second gas supply line (5) are interconnected to form a composite pipeline (7), and each of the gas supply lines is equipped with The system is equipped with a switch valve (8), and the composite pipeline (7) and the third gas transmission pipeline (6) are equipped with pressure reducing valves (10). The pressure reducing valves (10) are located downstream of the switch valve (8), and a mass flow meter (11) is installed downstream of the pressure reducing valves (10). A thermocouple sheath (16) is fused inside the reaction tube (15). A discharge pipeline (18) is connected to one side of the reaction tube (15), and a sampling tube and a tail gas absorption device are connected to the discharge pipeline (18). The system is characterized in that: The composite pipeline (7) is connected to a venting pipeline for venting hydrogen chloride in the opposite direction to the gas transmission direction. A venting valve (9) is provided on the venting pipeline, and two switching valves (8) are provided on the first gas transmission pipeline (4).

2. The evaluation device for the catalytic oxidation reaction of hydrogen chloride as described in claim 1, characterized in that: A premixing tank (12) is provided between the composite pipeline (7), the third gas transmission pipeline (6), and the reaction pipe (15).

3. The evaluation device for the catalytic oxidation reaction of hydrogen chloride as described in claim 1, characterized in that: A reaction valve (13) is provided at the inlet of the reaction tube (15).

4. The evaluation device for the catalytic oxidation reaction of hydrogen chloride as described in claim 3, characterized in that: The reaction valve (13) is connected to the reaction pipe (15) via a flange (14).

5. The evaluation device for the catalytic oxidation reaction of hydrogen chloride as described in claim 1, characterized in that: The reaction tube (15) is made of quartz.

6. The evaluation device for the catalytic oxidation reaction of hydrogen chloride as described in claim 1, characterized in that: Both sides of the reaction tube (15) can be detachably connected with a heat tracing cable (17).

7. The evaluation device for the catalytic oxidation reaction of hydrogen chloride as described in claim 1, characterized in that: A three-way valve (19) is provided on the discharge pipeline (18). One end of the three-way valve (19) is connected to the sampling bottle (20), and the other end is connected to the tail gas absorption device.

8. The evaluation device for the catalytic oxidation reaction of hydrogen chloride as described in claim 1, characterized in that: The exhaust gas absorption device includes two absorption bottles (21) connected in series, and the pipelines in the absorption bottles (21) are all long in and short out.

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