Multi-stage catalytic oxidation reactor for preparing chlorine from hydrogen chloride

Abstract

The invention discloses a multistage catalytic oxidation reactor for preparing chlorine from hydrogen chloride, and relates to the technical field of processes for preparing chlorine from hydrogen chloride, the multistage catalytic oxidation reactor comprises a plurality of catalytic oxidation reaction assemblies which are connected in series, and each catalytic oxidation reaction assembly comprises a catalytic oxidation reaction tank, a condensation dryer and a sulfuric acid tank dryer; wherein the catalytic oxidation reaction tank is provided with an air inlet pipe and an exhaust pipe, and the air inlet pipe is connected with an oxygen connecting pipe in parallel; the condensation dryer is used for condensing moisture in mixed gas formed by catalytic oxidation of feed gas; and the sulfuric acid tank dryer is used for drying residual moisture in the mixed gas and carrying out temperature compensation on the mixed gas through heat generated by drying the moisture by sulfuric acid. The reaction efficiency and the product purity are remarkably improved, heat is released while moisture is absorbed through the sulfuric acid tank dryer, mixed gas is heated, it is ensured that the high-temperature condition needed by the catalytic oxidation reaction is maintained, efficient water removal operation is achieved, and energy consumption is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of a process for preparing chlorine from hydrogen chloride, and in particular to a multi-stage catalytic oxidation reactor for preparing chlorine from hydrogen chloride. Background Art

[0002] Many industrial processes use chlorine as a raw material to produce hydrogen chloride as a byproduct. However, the byproduct hydrogen chloride is a cheap, low-demand, highly corrosive, and difficult to handle chemical. Therefore, people hope to find an economical and safe process for producing chlorine from hydrogen chloride. This can not only solve the problem of hydrogen chloride pollution to the environment, but also to a certain extent meet the growing demand for chlorine in industry.

[0003] There are many methods for preparing chlorine from hydrogen chloride in literature and patents, mainly electrolysis, direct oxidation with inorganic oxidants, and oxidation with catalyst air / oxygen (i.e., Deacon process). The electrolysis method consumes too much energy and is costly; the disadvantages of direct oxidation with inorganic oxidants are that the equipment is relatively complex, product separation is difficult, and energy consumption is high; the Deacon process is the process of oxidizing hydrogen chloride with oxygen or air in the presence of CuCl2 catalyst. The reaction of the Deacon process is a reversible reaction, and the product gas contains unreacted hydrogen chloride (HCl), oxygen, inert gases in the raw gas, and product chlorine and water vapor. The HCl conversion rate is usually less than 80%.

[0004] The patent with the authorization announcement number CN101130428B discloses a process for producing chlorine by catalytic oxidation of hydrogen chloride, which is composed of multiple groups of reactors and water separation devices. In the presence of a catalyst, hydrogen chloride and oxygen react chemically in the reactor to generate chlorine and water; the gas flowing out of the reactor is condensed and dehydrated in the water separation device, and the uncondensed gas enters the next reactor. Since the water is removed, the chemical equilibrium is broken, which is conducive to the continued reaction of unreacted hydrogen chloride and oxygen in the next reactor. After multiple groups of reactions and dehydration operations, the conversion rate of hydrogen chloride or oxygen can be close to 100%. The present invention has the advantages of high hydrogen chloride or oxygen conversion rate, simple equipment, stable operation and easy control.

[0005] However, in the above scheme, the condensation operation will cause the reaction temperature to decrease, while the catalytic oxidation reaction requires to be carried out at a higher temperature. Too low a temperature will significantly affect the reaction rate and the formation of products. In addition, under normal circumstances, the dew point temperature of hydrogen chloride is roughly between 27°C and 60°C, but the dew point temperature of hydrogen chloride may increase due to the moisture or oxygen content in the raw materials. If the hydrogen chloride gas contains a small amount of moisture, the dew point temperature may increase to 108.65°C. Therefore, the dew point temperature of hydrogen chloride partially overlaps with the dew point temperature of moisture. In the process of condensation and dehydration, the reaction gas is caused to be lower than the acid dew point, which may cause corrosion of subsequent heat exchangers and process pipelines, increasing the difficulty and cost of equipment maintenance. Summary of the invention

[0006] The purpose of the present invention is to solve the problem that when the conversion rate of hydrogen chloride to chlorine is improved by multi-stage catalytic oxidation in the prior art, the condensation and water removal process will reduce the reaction temperature of the subsequent catalytic reaction, affecting the reaction and causing pipeline corrosion, and a multi-stage catalytic oxidation reactor for preparing chlorine from hydrogen chloride is proposed.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: A multi-stage catalytic oxidation reactor for preparing chlorine from hydrogen chloride comprises a plurality of catalytic oxidation reaction components connected in series, wherein the catalytic oxidation reaction components comprise a catalytic oxidation reaction tank, a condensation dryer and a sulfuric acid tank dryer, wherein: The catalytic oxidation reaction tank is provided with an air inlet pipe and an exhaust pipe, the air inlet pipe is connected to an oxygen pipe, the exhaust pipe is connected to the top of the condensation dryer, and a slurry reaction bed structure is provided in the catalytic oxidation reaction tank, and hydrogen chloride and oxygen are mixed through the air inlet pipe and enter the slurry reaction bed structure for catalytic oxidation; The condensation dryer is used to condense the moisture in the mixed gas formed by catalytic oxidation of the raw gas, and the output end of the condensation dryer is connected to the bottom of the sulfuric acid tank dryer through a pipeline; The sulfuric acid tank dryer is used to dry the remaining moisture in the mixed gas and to perform temperature compensation on the mixed gas through the heat generated by drying the moisture with sulfuric acid. The output end of the sulfuric acid tank dryer is connected to the air inlet pipe of the subsequent catalytic oxidation reaction tank.

[0008] Preferably, the air inlet pipe, the exhaust pipe and the oxygen connecting pipe are all provided with independent solenoid valves.

[0009] Preferably, the slurry reaction bed structure includes a partition tube, and a support plate is arranged between the bottom of the partition tube and the inner wall of the catalytic oxidation reaction tank, so that a packing chamber is formed between the partition tube and the catalytic oxidation reaction tank, the packing chamber is filled with a slurry bed, and a porous aeration plate is arranged at the bottom of the slurry bed, and the air inlet pipe is connected to the porous aeration plate.

[0010] Preferably, the slurry bed is a slurry material formed by dispersing and suspending catalyst powder in a liquid inert reaction medium, and a mixed gas of hydrogen chloride and oxygen is introduced into the slurry bed to perform a catalytic oxidation reaction at 250-450° C. to prepare chlorine.

[0011] Preferably, the inert reaction medium is a binary mixture of lithium nitrate and potassium nitrate.

[0012] Preferably, the condensation dryer comprises a condensation tank, a rotating shaft is sealed and rotatably arranged inside the condensation tank, a driving mechanism is arranged between the rotating shafts of the multiple condensation dryers for synchronous driving, a plurality of blades are fixedly arranged on the outer wall of the rotating shaft, and an interlayer for the flow of heat exchange medium is arranged on the side wall of the condensation tank, and the interlayer is connected to a conduit for the circulation of heat exchange medium.

[0013] Preferably, the upper half of the condensation tank is a cylindrical condensation area, and the lower half is a conical gas collecting area, wherein the interlayer is in the cylindrical condensation area, and the output end of the condensation tank is located at the bottom of the gas collecting area.

[0014] Preferably, a liquid collecting annular groove is provided in the condensing area of ​​the condensing tank, and a plurality of heat exchange fins extending axially to the top of the condensing tank are evenly arranged in the circumferential direction of the liquid collecting annular groove.

[0015] Preferably, the driving mechanism comprises a driving motor, and a double-track pulley is fixedly mounted on the output end of the driving motor and one end of each rotating shaft located outside the condensing tank, and a plurality of the double-track pulleys are connected by belt transmission.

[0016] Preferably, at least three groups of the catalytic oxidation reaction components are provided, a plurality of the oxygen pipes are used to supplement oxygen at intervals, and a molar ratio of hydrogen chloride to the total amount of oxygen input by the plurality of oxygen pipes is 4:1 to 1:1.

[0017] Compared with the prior art, the present invention has the following advantages: The reactor uses multiple catalytic oxidation reaction components. Hydrogen chloride and oxygen gradually undergo catalytic oxidation reactions in each stage of the catalytic oxidation reaction tank. Through multi-stage reactions, not only the reaction is more complete, but the products after each stage of the reaction will undergo a dehydration operation, which can effectively break the chemical equilibrium and further promote the reaction in the positive direction, prompting the reaction to proceed in the direction of generating chlorine, so that the conversion rate of hydrogen chloride or oxygen is close to 100%, significantly improving the reaction efficiency and product purity.

[0018] The reactor is equipped with a condensation dryer and a sulfuric acid tank dryer. The former uses the condensation principle to remove moisture, while the latter absorbs moisture and releases heat through sulfuric acid. The condensation dryer efficiently removes moisture from the mixed gas, while the sulfuric acid tank dryer releases heat while absorbing moisture to heat up the mixed gas, ensuring that the high temperature conditions required for the catalytic oxidation reaction are maintained. It not only achieves efficient water removal operation, but also reduces energy consumption and ensures the complete removal of moisture from the reaction gas.

[0019] The reactor is equipped with a drive motor to drive the shaft to rotate. The blades rotate at high speed and use centrifugal force to separate the mixed gas. The lighter water vapor is thrown to the outside and comes into contact with the heat exchange fins for condensation and removal, while the heavier chlorine and hydrogen chloride gases are located at the center of rotation and rarely come into contact with the heat exchange fins for heat exchange, effectively avoiding the reaction gas below the acid dew point during the condensation and water removal process, thereby reducing the corrosion risk of subsequent heat exchangers and process pipelines, and improving the stability and service life of the equipment.

[0020] The reactor is connected to an oxygen pipe on the air inlet pipe of each catalytic oxidation reaction tank, so that oxygen can be mixed and enter the reaction in batches for multiple times. By controlling the amount and batches of oxygen added, the hydrogen chloride in a single reaction is in an excessive state, ensuring that the conversion rate of each catalytic oxidation reaction tank is not too high to cause excessive concentration of heat release, avoiding the loss of active components of the catalyst caused by untimely local heat exchange, and extending the service life of the oxidation catalyst. At the same time, the total amount of oxygen in the entire reaction process is in an excessive state, ensuring the forward progress of the reaction and improving the conversion rate of hydrogen chloride.

[0021] The reactor adopts a slurry reaction bed structure. The mixed gas is agitated to disperse and suspend the catalyst powder in a liquid inert reaction medium. The slurry reaction bed structure makes the temperature distribution in the bed more uniform, and can control the reaction to proceed under isothermal conditions, avoiding the sintering and deactivation of the catalyst caused by high temperature. The use of powder catalyst eliminates the influence of internal diffusion, improves the utilization rate and reaction capacity of the catalyst, and the catalyst powder is suspended in a liquid inert reaction medium for reaction, which further enhances the catalytic effect and makes the reaction more efficient and stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the overall structure of a multi-stage catalytic oxidation reactor for producing chlorine from hydrogen chloride proposed by the present invention; Figure 2 This is a schematic diagram of the top view of a multi-stage catalytic oxidation reactor for producing chlorine from hydrogen chloride proposed by the present invention; Figure 3 This is a schematic structural diagram of a single catalytic oxidation reaction assembly of a multi-stage catalytic oxidation reactor for producing chlorine from hydrogen chloride proposed by the present invention; Figure 4This is a schematic structural diagram of a catalytic oxidation reaction tank in a multi-stage catalytic oxidation reactor for producing chlorine from hydrogen chloride proposed by the present invention; Figure 5 This is a schematic diagram of the structure of a condensation dryer in a multi-stage catalytic oxidation reactor for producing chlorine from hydrogen chloride proposed by the present invention; Figure 6 This is a schematic diagram of the structure of a condenser in a multi-stage catalytic oxidation reactor for producing chlorine from hydrogen chloride proposed by the present invention; Figure 7 This is a schematic diagram of the structure of blades in a multi-stage catalytic oxidation reactor for producing chlorine from hydrogen chloride proposed by the present invention.

[0023] In the figure: 1. catalytic oxidation reaction component; 2. catalytic oxidation reaction tank; 21. air inlet pipe; 22. exhaust pipe; 23. oxygen pipe; 24. slurry reaction bed structure; 241. separator pipe; 242. support plate; 243. porous aeration plate; 3. condensation dryer; 31. condensation tank; 32. rotating shaft; 33. blades; 34. interlayer; 35. liquid collecting ring groove; 36. heat exchange fins; 4. sulfuric acid tank dryer; 5. solenoid valve; 6. drive motor; 61. double-track pulley; 62. belt. DETAILED DESCRIPTION

[0024] Reference Figure 1-3 A multi-stage catalytic oxidation reactor for preparing chlorine from hydrogen chloride comprises a plurality of catalytic oxidation reaction components 1 connected in series, wherein the catalytic oxidation reaction component 1 comprises a catalytic oxidation reaction tank 2, a condensation dryer 3 and a sulfuric acid tank dryer 4.

[0025] The catalytic oxidation reaction tank 2, the condensation dryer 3 and the sulfuric acid tank dryer 4 are sequentially arranged in series. The hydrogen chloride gas and the oxygen are mixed to form the raw gas, which is input into the catalytic oxidation reaction tank 2 and then catalytically oxidized under the action of the catalyst to generate the product chlorine. In the reaction of catalytic oxidation of hydrogen chloride to produce chlorine, under normal conditions, hydrogen chloride will not spontaneously oxidize to generate chlorine, but under specific catalyst and high temperature conditions, hydrogen chloride can react with oxygen to generate chlorine and water, which is usually used for industrial preparation of chlorine.

[0026] The chemical equation for this reaction is:

[0027] In the above reaction, the product gas includes unreacted hydrogen chloride, oxygen, inert gas in the raw material gas, and product chlorine and water vapor. The conversion rate of hydrogen chloride is usually less than 80%. The reactor adopts multiple catalytic oxidation reaction components 1 in series. Hydrogen chloride and oxygen gradually undergo catalytic oxidation reaction in each stage of catalytic oxidation reaction tank 2. Through multi-stage reaction, not only the reaction is more complete, but the product after each stage of reaction will be dehydrated by condensation dryer 3 and sulfuric acid tank dryer 4 to reduce the content of the product in the above reaction. Therefore, the chemical equilibrium can be effectively broken to further promote the reaction to move in the positive direction, and the reaction is prompted to proceed in the direction of generating chlorine, so that the conversion rate of hydrogen chloride or oxygen is close to 100%, which significantly improves the reaction efficiency and product purity.

[0028] Reference Figure 4 The catalytic oxidation reaction tank 2 is provided with an air inlet pipe 21 and an exhaust pipe 22. The air inlet pipe 21 is connected with an oxygen pipe 23. Hydrogen chloride is input through the air inlet pipe 21, and oxygen is mixed into the hydrogen chloride gas through the oxygen pipe 23. In order to ensure the reaction effect, the hydrogen chloride gas and oxygen are preheated at a temperature of 120°C to 180°C. The exhaust pipe 22 is connected to the top of the condensation dryer 3. The mixed gas after the reaction is introduced into the condensation dryer 3 for dehydration. A slurry reaction bed structure 24 is provided in the catalytic oxidation reaction tank 2. Hydrogen chloride and oxygen are mixed into the slurry reaction bed structure 24 through the air inlet pipe 21 for catalytic oxidation.

[0029] It can be seen from the above formula ① that the reaction of catalytic oxidation of hydrogen chloride to produce chlorine is an exothermic reaction. For every 1 mol of oxygen consumed, 115.4 kJ of heat is released. The violent redox reaction will cause the catalyst to overheat and the active components to sinter or lose more. The reactor is connected to the oxygen pipe 23 on the air inlet pipe 21 of each catalytic oxidation reaction tank 2, so that oxygen can be mixed into the reaction in batches for multiple times. By controlling the amount and batch of oxygen added, the hydrogen chloride in a single reaction is in an excessive state, ensuring that the conversion rate of each catalytic oxidation reaction tank 2 is not too high and the heat release is too concentrated. At the same time, the generated chlorine, water vapor and gas not participating in the reaction are all heat carriers, which avoids the loss of active components of the catalyst caused by untimely local heat exchange and prolongs the service life of the oxidation catalyst. After the reaction, the mixed gas is cooled by the condensation dryer 3, and it is easier to control when entering the downstream catalytic oxidation reaction component 1 for reaction to avoid excessive reaction temperature.

[0030] Reference Figure 1-3The catalytic oxidation reaction assembly 1 is provided with at least three groups. In this embodiment, the catalytic oxidation reaction assembly 1 is provided with four groups. The catalytic oxidation reaction assembly 1 at the end can be selectively provided with a condensation dryer 3 and a sulfuric acid tank dryer 4 according to the situation. In this embodiment, the catalytic oxidation reaction assembly 1 at the end is not provided with a condensation dryer 3 and a sulfuric acid tank dryer 4, and is directly discharged into the subsequent impurity removal equipment. A plurality of oxygen pipes 23 are supplemented with oxygen at intervals, and the molar ratio of the hydrogen chloride input amount to the total amount of oxygen input by the plurality of oxygen pipes 23 is 4:1 to 1:1. It can be seen from formula ① that for every 4 moles of hydrogen chloride reacted, 1 mole is consumed. The oxygen in the embodiment is preferably 2:1, ensuring that the hydrogen chloride can fully react, and the oxygen input by each oxygen pipe 23 is the same, so the molar ratio of the hydrogen chloride input to the oxygen input of a single oxygen pipe 23 is 8:1, then in the upstream catalytic oxidation reaction tank 2, the hydrogen chloride is in an excess state, and the oxygen introduced into the catalytic oxidation reaction tank 2 in the upstream stage can react completely, ensuring that the conversion rate of the catalytic oxidation reaction tank 2 is not too high to cause excessive concentration of heat release, and at the same time, the total amount of oxygen in the entire reaction process is in an excess state, ensuring the forward progress of the reaction and improving the conversion rate of hydrogen chloride.

[0031] Reference Figure 1-4 The slurry reaction bed structure 24 includes a partition tube 241. A support plate 242 is arranged between the bottom of the partition tube 241 and the inner wall of the catalytic oxidation reaction tank 2, so that a packing chamber is formed between the partition tube 241 and the catalytic oxidation reaction tank 2. The packing chamber is filled with a slurry bed, and a porous aeration plate 243 is arranged at the bottom of the slurry bed. The air inlet pipe 21 is connected with the porous aeration plate 243. The reaction mixed gas enters the catalytic oxidation reaction tank 2 and forms small bubbles through the porous aeration plate 243 to agitate upward. During the rising process of the bubbles, the reaction is completed under the action of the catalyst in the slurry bed.

[0032] The slurry bed is a slurry material formed by catalyst powder being dispersed and suspended in a liquid inert reaction medium. The inert reaction medium is a binary mixture of lithium nitrate and potassium nitrate. The catalyst is one or more of metal oxides, self-transition metals or alkali metals, and can also be a precious metal catalyst such as platinum, palladium, rhodium, etc. In this embodiment, the catalyst uses a cerium copper potassium composite oxide catalyst, and the particle size of the catalyst is 1 μm. A mixed gas of hydrogen chloride and oxygen is introduced into the slurry bed, and a catalytic oxidation reaction is carried out at 250 to 450° C. to prepare chlorine. The mixed gas is agitated by aeration to disperse and suspend the catalyst powder in the liquid inert reaction medium. The slurry reaction bed structure 24 makes the temperature distribution in the bed more uniform, and the reaction can be controlled to proceed under isothermal conditions, further avoiding the sintering and deactivation of the catalyst caused by high temperature. The use of a powder catalyst eliminates the influence of internal diffusion, improves the utilization rate and reaction capacity of the catalyst, and the catalyst powder is suspended in a liquid inert reaction medium for reaction, further improving the catalytic effect, making the reaction more efficient and stable.

[0033] The condensation dryer 3 is used to condense the moisture in the mixed gas formed by catalytic oxidation of the raw gas. The output end of the condensation dryer 3 is connected to the bottom of the sulfuric acid tank dryer 4 through a pipeline, and the mixed gas passing through the condensation dryer 3 is input into the sulfuric acid tank dryer 4 for secondary drying.

[0034] Reference Figure 5-7 The condensation dryer 3 includes a condensation tank 31, in which a rotating shaft 32 is sealed and rotatably provided, and a driving mechanism is provided between the rotating shafts 32 of multiple condensation dryers 3 for synchronous driving. A plurality of blades 33 are fixedly provided on the outer wall of the rotating shaft 32, and a side wall of the condensation tank 31 is provided with an interlayer 34 for the flow of heat exchange medium, and the interlayer 34 is connected with a conduit for the circulation of the heat exchange medium, which is not shown in the figure. Usually, the temperature of the heat exchange medium is controlled at 60-90°C, and the heat exchange medium is heat transfer oil. The high-temperature mixed gas after the reaction enters the condensation tank 31 and exchanges heat with the heat exchange medium in the interlayer 34, wherein the water vapor is pre-cooled and liquefied and is trapped, which reduces the content of water vapor in the subsequent reaction process, thereby promoting the forward reaction, and can reduce the temperature of the reaction gas, avoid continuous reaction of the high-temperature reaction gas, and avoid overheating caused by heat accumulation.

[0035] Reference Figure 5-7 The upper half of the condensation tank 31 is a cylindrical condensation area, and the lower half is a conical gas collection area, wherein the interlayer 34 is in the cylindrical condensation area, and the output end of the condensation tank 31 is located at the bottom of the gas collection area.

[0036] Reference Figure 5-7 A liquid collecting annular groove 35 is arranged in the condensation area of ​​the condensation tank 31, and a plurality of heat exchange fins 36 extending axially to the top of the condensation tank 31 are evenly arranged in the circumferential direction of the liquid collecting annular groove 35. The condensed water flows downward along the heat exchange fins 36 into the liquid collecting annular groove 35 and is discharged through an external pipe, wherein the heat exchange fins 36 can increase the heat exchange area and improve the heat exchange effect.

[0037] Since the dew point temperature of hydrogen chloride may increase due to the moisture or oxygen content in the raw materials, if the hydrogen chloride gas contains a small amount of moisture, the dew point temperature may increase to 108.65°C, and the dew point temperature of water is 100°C. Therefore, the dew point temperature of hydrogen chloride and the dew point temperature of water partially overlap, and the reaction gas is caused to be lower than the acid dew point during the condensation and dehydration process, which may cause corrosion of subsequent heat exchangers and process pipelines, increasing the difficulty and cost of equipment maintenance. Under the action of the driving mechanism, multiple shafts 32 rotate synchronously, causing the blades 33 to rotate to form centrifugal force. Under standard conditions, i.e., 0°C and 1 standard atmospheric pressure, the density of hydrogen chloride gas is about 1.64 g / L, the density of water vapor is about 0.804 g / L, and the density of chlorine is about 3.2 g / L, these values ​​may vary with changes in temperature and pressure. Generally speaking, under the same conditions, chlorine has the highest density, followed by hydrogen chloride, and water vapor has the lowest density. Under the action of centrifugal force, water vapor with lower density is thrown to the outside and contacts the heat exchange fins 36 for condensation and removal, while heavier chlorine and hydrogen chloride are located at the center of rotation and rarely contact the heat exchange fins 36 for heat exchange, which effectively avoids the reaction gas being lower than the acid dew point during the condensation and dehydration process, thereby reducing the corrosion risk of subsequent heat exchangers and process pipelines and improving the stability and service life of the equipment.

[0038] Reference Figure 1-3 The driving mechanism includes a driving motor 6. The output end of the driving motor 6 and one end of each rotating shaft 32 located outside the condensing tank 31 are fixedly installed with a double-track pulley 61, and the multiple double-track pulleys 61 are connected by belts 62.

[0039] The sulfuric acid tank dryer 4 is used to dry the remaining moisture in the mixed gas, and the heat generated by the sulfuric acid drying the moisture is used to compensate the temperature of the mixed gas. The output end of the sulfuric acid tank dryer 4 is connected to the air inlet pipe 21 of the subsequent catalytic oxidation reaction tank 2. The sulfuric acid tank dryer 4 is a prior art, and gas drying is achieved through the water absorption of sulfuric acid. Since the temperature of the mixed gas will be greatly reduced after passing through the condensation dryer 3, and may even be unable to meet the reaction temperature, the sulfuric acid tank dryer 4 will release heat while absorbing moisture, and the mixed gas will be heated to ensure that the high temperature conditions required for the catalytic oxidation reaction are maintained, which not only achieves efficient water removal operation, but also reduces energy consumption and ensures the complete removal of moisture in the reaction gas.

[0040] It should be noted that, although the use of sulfuric acid tank dryer 4 alone can prevent the mixed gas from reaching the acid dew point and causing pipeline corrosion, the consumption of sulfuric acid will increase. At the same time, the catalytic oxidation reaction and water absorption drying are both exothermic processes. Continuous heat release will make the temperature too high and destroy the balance of the reaction system.

[0041] Independent solenoid valves 5 (part of the solenoid valves 5 are not shown in the attached drawings) are provided on the air intake pipe 21, the exhaust pipe 22, the oxygen pipe 23 and other connecting pipes involved in flow control, which is conducive to accurately controlling the opening and closing of each pipeline and regulating the flow.

[0042] The specific working principle of the present invention is as follows: Hydrogen chloride gas and a small amount of oxygen are mixed to form raw gas, which is input into the upstream catalytic oxidation reaction tank 2. Small bubbles are formed through the porous aeration plate 243 and agitated upward. Catalytic oxidation is carried out during the rising process of the bubbles. The hydrogen chloride is in an excess state, and the oxygen introduced into the upstream catalytic oxidation reaction tank 2 can react completely, ensuring that the conversion rate of the catalytic oxidation reaction tank 2 is not too high to cause excessive concentration of heat release.

[0043] The mixed gas enters the condensation dryer 3. Under the action of the driving mechanism, multiple shafts 32 rotate synchronously, causing the blades 33 to rotate to generate centrifugal force. Under the action of the centrifugal force, the water vapor with lower density is thrown to the outside and contacts the heat exchange fins 36 for condensation and removal, while the heavier chlorine and hydrogen chloride gases are located at the center of rotation and rarely contact the heat exchange fins 36 for heat exchange, which effectively avoids the reaction gas being lower than the acid dew point during the condensation and water removal process, thereby reducing the corrosion risk of subsequent heat exchangers and process pipelines. The condensed water flows downward along the heat exchange fins 36 into the liquid collecting ring groove 35 and is discharged through an external pipe.

[0044] The mixed gas continues to enter the sulfuric acid tank dryer 4 to dry the remaining water vapor, and the heat generated by the sulfuric acid drying the water is used to compensate the temperature of the mixed gas to ensure that the high temperature conditions required for the catalytic oxidation reaction are maintained.

[0045] After drying, the mixed gas enters the downstream catalytic oxidation reaction component 1, and at the same time, oxygen is compensated. Hydrogen chloride and oxygen gradually undergo catalytic oxidation reaction in each stage of the catalytic oxidation reaction tank 2. Through multi-stage reaction, not only the reaction is more complete, but the product after each stage of reaction will pass through the condensation dryer 3 and the sulfuric acid tank dryer 4 for dehydration operation to reduce the content of the product in the above reaction. Therefore, it can effectively break the chemical balance and further promote the reaction to move in the positive direction, prompting the reaction to proceed in the direction of generating chlorine, which significantly improves the reaction efficiency and product purity.

Claims

1. A multi-stage catalytic oxidation reactor for preparing chlorine from hydrogen chloride, characterized in that: The invention comprises a plurality of catalytic oxidation reaction assemblies (1) connected in series, wherein the catalytic oxidation reaction assembly (1) comprises a catalytic oxidation reaction tank (2), a condensation dryer (3) and a sulfuric acid tank dryer (4), wherein: The catalytic oxidation reaction tank (2) is provided with an air inlet pipe (21) and an exhaust pipe (22), the air inlet pipe (21) is connected to an oxygen pipe (23), the exhaust pipe (22) is connected to the top of the condenser dryer (3), and a slurry reaction bed structure (24) is provided in the catalytic oxidation reaction tank (2), and hydrogen chloride and oxygen are mixed through the air inlet pipe (21) and enter the slurry reaction bed structure (24) for catalytic oxidation; The condensation dryer (3) is used to condense water in the mixed gas formed by catalytic oxidation of the raw gas, and the output end of the condensation dryer (3) is connected to the bottom of the sulfuric acid tank dryer (4) through a pipeline; The condensation dryer (3) comprises a condensation tank (31), a rotating shaft (32) is provided in a sealed and rotatable manner inside the condensation tank (31), a driving mechanism is provided between the rotating shafts (32) of the plurality of condensation dryers (3) for synchronous driving, a plurality of blades (33) are fixedly provided on the outer wall of the rotating shaft (32), and a sandwich (34) for the flow of a heat exchange medium is provided on the side wall of the condensation tank (31), the sandwich (34) is connected to a conduit for the circulation of the heat exchange medium, the upper half of the condensation tank (31) is a cylindrical condensation area, and the lower half is a conical gas collection area, wherein the sandwich (34) is located in the cylindrical condensation area, the output end of the condensation tank (31) is located at the bottom of the gas collection area, a liquid collecting annular groove (35) is provided in the condensation area of ​​the condensation tank (31), and a plurality of heat exchange fins (36) extending axially to the top of the condensation tank (31) are evenly provided in the circumferential direction of the liquid collecting annular groove (35); The sulfuric acid tank dryer (4) is used to dry the remaining moisture in the mixed gas and to perform temperature compensation on the mixed gas by using the heat generated by drying the moisture with sulfuric acid. The output end of the sulfuric acid tank dryer (4) is connected to the air inlet pipe (21) of the subsequent catalytic oxidation reaction tank (2).

2. A multi-stage catalytic oxidation reactor for preparing chlorine from hydrogen chloride according to claim 1, characterized in that: The air intake pipe (21), the exhaust pipe (22) and the oxygen pipe (23) are all provided with independent solenoid valves (5).

3. The multi-stage catalytic oxidation reactor for preparing chlorine from hydrogen chloride according to claim 1, characterized in that: The slurry reaction bed structure (24) comprises a partition tube (241), a support plate (242) being arranged between the bottom of the partition tube (241) and the inner wall of the catalytic oxidation reaction tank (2), so that a packing chamber is formed between the partition tube (241) and the catalytic oxidation reaction tank (2), the packing chamber being filled with a slurry bed, and a porous aeration plate (243) being arranged at the bottom of the slurry bed, and the air inlet pipe (21) being in communication with the porous aeration plate (243).

4. A multi-stage catalytic oxidation reactor for preparing chlorine from hydrogen chloride according to claim 3, characterized in that: The slurry bed is a slurry material formed by dispersing and suspending catalyst powder in a liquid inert reaction medium. A mixed gas of hydrogen chloride and oxygen is introduced into the slurry bed to perform a catalytic oxidation reaction at 250-450° C. to prepare chlorine.

5. A multi-stage catalytic oxidation reactor for preparing chlorine from hydrogen chloride according to claim 4, characterized in that: The inert reaction medium is a binary mixture of lithium nitrate and potassium nitrate.

6. The multi-stage catalytic oxidation reactor for preparing chlorine from hydrogen chloride according to claim 1, characterized in that: The driving mechanism comprises a driving motor (6), and a double-track pulley (61) is fixedly mounted on the output end of the driving motor (6) and one end of each rotating shaft (32) located outside the condensing tank (31), and the plurality of double-track pulleys (61) are connected to each other through a belt (62).

7. The multi-stage catalytic oxidation reactor for preparing chlorine from hydrogen chloride according to claim 1, characterized in that: The catalytic oxidation reaction assembly (1) is provided with at least three groups, and the plurality of oxygen pipes (23) replenish oxygen at intervals, and the molar ratio of hydrogen chloride to the total amount of oxygen input by the plurality of oxygen pipes (23) is 4:1 to 1:1.

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