A method for purifying hydrogen bromide by removing bromine, water and impurities before liquefaction

Abstract

The application belongs to the technical field of fine chemical industry, and particularly relates to a hydrogen bromide purification method for removing bromine, water and impurities before liquefaction, which comprises the following steps: S1, removal of free bromine: hydrogen bromide gas is introduced into a first bromine removal tank filled with a red phosphorus filler layer; S2, preliminary removal of water: the gas treated in S1 is introduced into a first drying tank filled with liquid phosphorus tribromide; S3, deep removal of trace water: the gas treated in S2 is introduced into a second drying tank filled with resin or mordenite; and S4, separation of mechanical impurities: the gas treated in S3 is introduced into a cyclone separator. By adopting the red phosphorus filler layer and controlling the loading amount, particle size and loading density of the red phosphorus, the free bromine in the hydrogen bromide gas can be efficiently removed, liquid phosphorus tribromide is used as a drying medium and is supplemented in real time to maintain the mass concentration of the phosphorus tribromide, so that the bromine and water content in the gas can be effectively reduced, and high-quality gas is provided for subsequent deep drying and impurity separation.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical technology, specifically a method for purifying hydrogen bromide by removing bromine, water, and impurities before liquefaction. Background Technology

[0002] Liquefied hydrogen bromide, as a key chemical raw material, plays an irreplaceable role in the chemical, pharmaceutical, and electronics industries. In the chemical industry, it is a fundamental raw material for the synthesis of inorganic bromides and alkyl bromides; in the pharmaceutical industry, its high purity directly affects the quality and efficacy of drug synthesis; and in the electronics industry, especially in semiconductor manufacturing, liquefied hydrogen bromide, as an environmentally friendly alternative to fluorocarbon gases, can precisely etch polycrystalline silicon chips, which is crucial for improving the performance and product yield of electronic devices. With increasingly stringent environmental requirements, its potential application value in green chemistry is becoming increasingly prominent.

[0003] Hydrogen bromide gas produced in industry usually contains free bromine, moisture, and mechanical impurities (such as metal particles and dust). These impurities can easily lead to equipment corrosion and reduced gas purity, as well as uneven semiconductor etching, deterioration of electronic device performance, and even production accidents.

[0004] Traditional bromine removal methods are inefficient, and adsorbents are prone to failure, resulting in poor removal of free bromine. Preliminary moisture removal processes cannot achieve deep drying, resulting in high dew points that cannot meet high purity requirements. In addition, the separation of mechanical impurities usually relies on a single filtration device, which is difficult to completely remove submicron particles, leaving the gas with a significant amount of impurities. Summary of the Invention

[0005] The purpose of this invention is to provide a method for purifying hydrogen bromide by removing bromine, water, and impurities before liquefaction, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for purifying hydrogen bromide by removing bromine, water, and impurities before liquefaction includes the following steps:

[0008] S1. Removal of free bromine: Hydrogen bromide gas is introduced into a primary bromine removal tank filled with red phosphorus packing.

[0009] S2, Preliminary removal of moisture: The gas treated by S1 is passed into a primary drying tank filled with liquid phosphorus tribromide.

[0010] S3. Deep removal of trace water: The gas treated by S2 is passed into a secondary drying tank filled with resin or mordenite.

[0011] S4. Separation of mechanical impurities: The gas treated in S3 is passed into a dust removal device to remove particles with a diameter >5μm, and then into a cyclone separator. The gas inlet angle is controlled at 80-100°, the flow rate is 0.5-1m / s, and the centrifugal acceleration is 500-1500m / s². The treated gas is then passed into a condensation device with a final liquefaction temperature of -25~-15℃ and a heat exchange area of ​​12-18m² to liquefy hydrogen bromide. Finally, the gas is sent to a liquefied storage tank.

[0012] A gas buffer tank is installed between the primary bromine removal tank and the primary drying tank. A dew point detector is installed at the outlet of the secondary drying tank. The inner wall of the gas pipeline connecting the primary bromine removal tank, the primary drying tank, the secondary drying tank and the cyclone separator is coated with polytetrafluoroethylene.

[0013] By adopting the above technical solution: in the free bromine removal step, a red phosphorus packing layer is used and the red phosphorus loading amount, particle size, and packing density are controlled, which can efficiently remove free bromine from hydrogen bromide gas; at the same time, in the preliminary moisture removal step, liquid phosphorus tribromide is used as a drying medium and replenished in real time to maintain the concentration of phosphorus tribromide, ensuring the preliminary moisture removal effect. This can effectively reduce the bromine and moisture content in the gas, providing high-quality gas for subsequent deep drying and impurity separation, and avoiding the impact of impurity residue on subsequent processes.

[0014] Preferably, the packing density of red phosphorus in S1 is 1200-1800 kg / m³, and the particle size is 2-5 mm.

[0015] Preferably, the mass concentration of liquid phosphorus tribromide in S2 is 200-600 kg / m³, and phosphorus tribromide is replenished in real time during the reaction to maintain the mass fraction of phosphorus tribromide ≥85%.

[0016] Preferably, the resin in S3 is a strong acid cation exchange resin with an exchange capacity ≥ 4.5 mmol / g and a particle size of 0.5-1.5 mm; the silica-alumina molar ratio of the mordenite is (10-20):1, the pore size is 0.4-0.7 nm, and the packing density is 300-500 kg / m³.

[0017] Preferably, in S4, the ratio of the cylinder height to the diameter of the cyclone separator is 3:1 to 5:1, and the width of the gas inlet is 1 / 5 to 1 / 3 of the cylinder diameter.

[0018] Preferably, the condensation device in S4 adopts a two-stage series refrigeration. The first stage refrigeration medium is an aqueous solution of ethylene glycol, and the temperature is controlled at -5 to 0°C. The second stage is a liquid nitrogen circulation, and the temperature is controlled at -25 to -15°C.

[0019] Preferably, the pressure fluctuation range of the gas buffer tank is ≤±5%, and the gas residence time is 10-30s.

[0020] Preferably, the dew point detector monitors the gas dew point in real time to ≤-60℃, and dynamically adjusts the temperature and gas flow rate of the secondary drying tank according to the detection results.

[0021] Preferably, the bottom of the cyclone separator in S4 is equipped with a vibrating screening device with a screen mesh size of 100-200 mesh, a vibration frequency of 20-50Hz, and an amplitude of 1-3mm.

[0022] Preferably, the polytetrafluoroethylene coating has a roughness Ra≤0.8μm and a thickness of 50-100μm, and the gas pipeline is backflushed with 0.3-0.5MPa nitrogen every 2-4 hours.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. This invention utilizes a red phosphorus packing layer and controls the amount, particle size, and packing density of red phosphorus in the free bromine removal step to efficiently remove free bromine from hydrogen bromide gas. Simultaneously, in the initial moisture removal step, liquid phosphorus tribromide is used as a drying medium and replenished in real time to maintain the concentration of phosphorus tribromide, ensuring the initial moisture removal effect. This effectively reduces the bromine and moisture content in the gas, providing high-quality gas for subsequent deep drying and impurity separation, and avoiding the impact of impurity residues on subsequent processes.

[0025] 2. In the deep removal step of trace water, this invention uses a strongly acidic cation exchange resin or mordenite as the drying medium, and controls the packing density, particle size, and silicon-aluminum molar ratio to deeply remove trace water from the gas. In the separation step of mechanical impurities, the cyclone separator, by optimizing the ratio of cylinder height to diameter, gas inlet width, and centrifugal acceleration, combined with the screen mesh number, frequency, and amplitude of the vibrating sieve device, can effectively separate mechanical impurities from the gas. At the same time, the condensation device adopts a two-stage series refrigeration, combined with ethylene glycol aqueous solution and liquid nitrogen circulation, to further reduce the temperature to condense impurities, ensuring the high efficiency of gas drying and separation.

[0026] 3. This invention includes a gas buffer tank between the primary bromine removal tank and the primary drying tank to control pressure fluctuation range and gas residence time, thereby stabilizing gas flow and reducing the impact of pressure fluctuations on the primary drying tank and subsequent process equipment, ensuring the overall stability of the equipment operation. The dew point detector monitors the gas dew point in real time and dynamically adjusts the temperature and gas flow rate of the secondary drying tank, accurately controlling the degree of gas drying and avoiding over-drying or under-drying. Furthermore, the polytetrafluoroethylene coating on the inner wall of the pipeline and the periodic nitrogen backflushing prevent pipeline corrosion and blockage, extending the service life of the primary bromine removal tank, drying tank, and cyclone separator, ensuring the long-term stable operation of the process. Attached Figure Description

[0027] Figure 1 This is a schematic diagram showing the connection relationship of the equipment used in this invention;

[0028] Figure 2 This is a flowchart of the present invention. Detailed Implementation

[0029] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Please see the appendix Figure 1 This invention provides a method for purifying hydrogen bromide by removing bromine, water, and impurities before liquefaction, comprising the following steps:

[0031] S1. Removal of free bromine: Hydrogen bromide gas is introduced into a primary bromine removal tank filled with red phosphorus packing, and the gas temperature is controlled at 20-40℃, the flow rate at 1-3m / s, and the pressure at 0.1-0.2MPa.

[0032] S2. Preliminary removal of moisture: The gas treated by S1 is passed into a primary drying tank filled with liquid phosphorus tribromide, and the temperature is controlled at 20-40℃, the flow rate at 1-3m / s, and the pressure at 0.1-0.2MPa.

[0033] S3. Deep removal of trace water: The gas treated by S2 is passed into a secondary drying tank filled with resin or mordenite, and the temperature is controlled at 15-35℃, the flow rate at 0.8-2.5m / s, and the pressure at 0.08-0.18MPa.

[0034] S4. Separation of mechanical impurities: The gas treated in S3 is passed into a dust removal device to remove particles with a diameter >5μm, and then into a cyclone separator. The gas inlet angle is controlled at 80-100°, the flow rate is 0.5-1m / s, and the centrifugal acceleration is 500-1500m / s². The treated gas is then passed into a condensation device with a final liquefaction temperature of -25~-15℃ and a heat exchange area of ​​12-18m² to liquefy hydrogen bromide. Finally, the gas is sent to a liquefied storage tank.

[0035] A gas buffer tank is installed between the primary bromine removal tank and the primary drying tank. A dew point detector is installed at the outlet of the secondary drying tank. The inner wall of the gas pipeline connecting the primary bromine removal tank, the primary drying tank, the secondary drying tank and the cyclone separator is coated with polytetrafluoroethylene.

[0036] Specifically, by passing hydrogen bromide gas into a primary bromine removal tank filled with red phosphorus packing, and controlling the gas temperature at 20-40℃, flow rate at 1-3 m / s, and pressure at 0.1-0.2 MPa, free bromine is effectively adsorbed and removed, thus purifying the gas and ensuring the safety and efficiency of the primary drying tank, secondary drying tank, and cyclone separator in subsequent treatment steps. Furthermore, by passing the gas treated by S1 into a primary drying tank filled with liquid phosphorus tribromide, and controlling the temperature at 20-40℃, flow rate at 1-3 m / s, and pressure at 0.1-0.2 MPa, the gas reacts with moisture in the gas to generate phosphorous acid, removing most of the moisture and achieving the initial drying of the hydrogen bromide gas. This lays the foundation for deep drying. By passing the gas treated by S2 into a secondary drying tank filled with resin or mordenite, and controlling the temperature at 15-35℃, the flow rate at 0.8-2.5m / s, and the pressure at 0.08-0.18MPa, trace moisture is deeply removed, thereby improving the dryness of the gas and ensuring that the moisture content in the gas is reduced to an extremely low level. By passing the gas treated by S3 into a dust removal device, particles with a diameter >5μm are removed, achieving the purpose of preliminary gas purification and removal of large particulate impurities, thereby reducing wear and blockage of subsequent equipment and improving the operating efficiency and stability of the entire system. By controlling the gas inlet angle at 80-100° and the flow rate at 0.With a speed of 5-1 m / s and a centrifugal acceleration of 500-1500 m / s², the gas rotates at high speed within the cyclone separator, further separating and removing smaller particulate impurities, thereby improving gas purity and creating purer conditions for subsequent condensation and liquefaction. The treated gas is then passed into a condensation device with a final liquefaction temperature of -25~-15℃ and a heat exchange area of ​​12-18 m², achieving efficient condensation and liquefaction of hydrogen bromide gas at low temperatures, thus converting gaseous hydrogen bromide into liquid for easy storage and transportation. The liquefied hydrogen bromide is then sent to a liquefied storage tank for safe storage, facilitating subsequent use and transportation. A gas buffer tank is installed between the primary bromine removal tank and the primary drying tank to stabilize pressure fluctuations and mitigate gas pressure shocks. A dew point detector is installed at the outlet of the secondary drying tank to monitor the gas dew point in real time and dynamically... The temperature and flow rate of the drying tank are adjusted to precisely control the dryness of the gas, ensuring the consistency and stability of the drying quality. A polytetrafluoroethylene (PTFE) coating is applied to the inner wall of the gas pipeline connecting the primary bromine removal tank, primary drying tank, secondary drying tank, and cyclone separator. This reduces the roughness of the pipeline inner wall and decreases gas flow resistance, thereby improving gas transmission efficiency. The PTFE coating also possesses good chemical stability and high-temperature resistance, effectively preventing corrosion and contamination of the gas pipeline. The primary drying tank is equipped with a temperature sensor and cooling coils to control the reaction temperature to ≤40℃. The heat generated by the reaction is promptly dissipated through the cooling coils. Combined with dynamic temperature control by the temperature sensor, the internal temperature of the tank is kept ≤40℃, thus preventing localized overheating that could lead to phosphorus tribromide decomposition or equipment damage, ensuring a safe and stable drying process.

[0037] Please see the appendix Figure 2 The packing density of red phosphorus in S1 is 1200-1800 kg / m³, and the particle size is 2-5 mm.

[0038] Specifically, by setting the red phosphorus packing density to 1200-1800 kg / m³ in step S1, sufficient contact area is provided to promote the chemical reaction between hydrogen bromide and red phosphorus, thereby achieving efficient removal of free bromine. A packing density within this range ensures sufficient contact time between the gas flow and the red phosphorus packing material, thus improving the removal rate of free bromine. Setting the red phosphorus particle size to 2-5 mm controls the particle size to optimize gas flow and reaction efficiency, thereby balancing gas flow rate and reaction contact area. Appropriate particle size reduces gas flow resistance while maintaining sufficient surface area for the reaction between hydrogen bromide and red phosphorus, ensuring effective removal of free bromine. Setting the red phosphorus packing density to 1200-1800 kg / m³ adjusts the porosity between red phosphorus particles to optimize gas flow and reaction kinetics, thereby improving reaction efficiency and reducing pressure drop.

[0039] Please see the appendix Figure 2 The mass concentration of liquid phosphorus tribromide in S2 is 200-600 kg / m³, and phosphorus tribromide is replenished in real time during the reaction to maintain the mass fraction of phosphorus tribromide ≥85%.

[0040] Specifically, by setting the mass concentration of liquid phosphorus tribromide to 200-600 kg / m³ in step S2, sufficient reaction medium is provided to promote the chemical reaction of moisture in the hydrogen bromide gas, thereby effectively removing most of the moisture. An appropriate mass concentration of liquid phosphorus tribromide ensures that the gas comes into contact with sufficient phosphorus tribromide during its passage, thus improving the efficiency of moisture removal. By continuously replenishing liquid phosphorus tribromide during the reaction to maintain a phosphorus tribromide mass fraction ≥85%, the reaction activity and stability are maintained, ensuring a continuous and efficient moisture removal effect.

[0041] Please see the appendix Figure 2 The resin in S3 is a strong acidic cation exchange resin with an exchange capacity ≥4.5mmol / g and a particle size of 0.5-1.5mm; the silica-alumina molar ratio of the mordenite is (10-20):1, the pore size is 0.4-0.7nm, and the packing density is 300-500kg / m³.

[0042] Specifically, by using a strongly acidic cation exchange resin in step S3 and setting its exchange capacity to ≥4.5 mmol / g, it achieves efficient adsorption and removal of trace water, thereby achieving deep drying. The high exchange capacity of the resin provides more active sites, thereby enhancing the adsorption capacity for moisture and ensuring that the trace amounts of residual moisture in the gas are effectively removed. By setting the packing density of mordenite to 300-500 kg / m³, it balances the adsorption efficiency and gas flow resistance, thereby achieving efficient moisture removal and a low pressure drop.

[0043] Please see the appendix Figure 2 In S4, the ratio of the cylinder height to the diameter of the cyclone separator is 3:1 to 5:1, and the width of the gas inlet is 1 / 5 to 1 / 3 of the cylinder diameter.

[0044] Specifically, by setting the cylinder height to diameter ratio of the cyclone separator to 3:1-5:1 in step S4, the gas flow path is optimized and the separation effect is enhanced, thereby achieving more efficient separation of mechanical impurities. A suitable cylinder height to diameter ratio can extend the rotation path of the gas in the cyclone separator, increase the centrifugal force, and make it easier for heavier mechanical impurities to be deposited on the separator wall, thus being effectively separated.

[0045] Please see the appendix Figure 2 In S4, the condenser uses a two-stage series refrigeration system. The first stage uses an aqueous ethylene glycol solution as the refrigerant and the temperature is controlled between -5 and 0°C. The second stage uses liquid nitrogen circulation and the temperature is controlled between -25 and -15°C.

[0046] Specifically, by employing a two-stage series refrigeration condenser in step S4, the gas temperature is reduced in stages to improve the efficiency of mechanical impurity separation, thereby enabling more thorough removal of impurities. This two-stage series refrigeration condenser allows for more precise control of the gas temperature to meet the needs of removing different impurities. The first stage uses an aqueous ethylene glycol solution as the refrigerant and controls the temperature to -5 to 0°C, which initially reduces the gas temperature to condense some water vapor and larger particulate impurities, thus reducing the load on subsequent liquid nitrogen refrigeration. The second stage uses liquid nitrogen as the refrigerant and controls the temperature to -25 to -15°C, which deeply cools the gas to further condense finer impurities and water vapor, thereby improving the purity of the gas.

[0047] Please see the appendix Figure 2 The pressure fluctuation range of the gas buffer tank is ≤±5%, and the gas residence time is 10-30s.

[0048] Specifically, limiting the range of pressure fluctuations can reduce wear and tear and potential safety risks to the primary drying tank and subsequent processing equipment caused by sudden pressure changes. At the same time, it can ensure the continuity and uniformity of the gas processing process. Appropriately extending the residence time of the gas can ensure that impurities in the gas have enough time to contact the processing medium, thereby improving the removal efficiency. Meanwhile, it can prevent the gas from staying in the buffer tank for too long, which would lead to unnecessary energy consumption and efficiency reduction.

[0049] Please see the appendix Figure 2 The dew point detector monitors the gas dew point in real time (≤-60℃) and dynamically adjusts the temperature and gas flow rate of the secondary dryer based on the detection results.

[0050] Specifically, dew point temperature is an important parameter for measuring the water vapor content in a gas. The lower the dew point, the less water vapor is in the gas. By monitoring the dew point in real time, the drying process can be precisely controlled to ensure that the dryness of the gas always meets the requirements.

[0051] Please see the appendix Figure 2 The bottom of the cyclone separator in S4 is equipped with a vibrating screen device with a screen mesh size of 100-200 mesh, a vibration frequency of 20-50Hz, and an amplitude of 1-3mm.

[0052] Specifically, the vibrating sieving device can more effectively separate solid impurities deposited at the bottom of the cyclone separator from the gas through vibration, thereby improving separation efficiency. At the same time, vibration can prevent solid impurities from accumulating and clogging at the bottom of the cyclone separator, ensuring smooth operation of gas purification. By setting the screen mesh to 100-200 mesh, the screening precision can be adjusted as needed to ensure that only solid particles that meet the requirements are separated.

[0053] Please see the appendix Figure 2 The roughness of the polytetrafluoroethylene coating Ra≤0.8μm and the thickness is 50-100μm. Nitrogen gas at 0.3-0.5MPa is backflushed into the gas pipeline every 2-4 hours.

[0054] Specifically, a coating roughness Ra≤0.8μm indicates a very smooth coating surface, which helps reduce frictional resistance during fluid flow, thereby reducing energy consumption. Simultaneously, the smooth surface helps reduce the adhesion and deposition of particulate matter, keeping the gas pipeline clean and reducing maintenance requirements. A coating thickness of 50-100μm provides sufficient protection against corrosion and wear, while maintaining the coating's flexibility to accommodate the bending and vibration of the gas pipeline. Regular backflushing with nitrogen removes dust, particulate matter, and other impurities from the gas pipeline, keeping it unobstructed and reducing the risk of blockage. Furthermore, the inert nature of nitrogen reduces the risk of oxidation and corrosion from hydrogen bromide gas within the pipeline.

[0055] Example 1

[0056] 1. Removal of free bromine:

[0057] Hydrogen bromide gas was introduced from the bottom of the primary bromine removal tank at a flow rate of 2 m / s. The tank was filled with 200 kg of red phosphorus with a particle size of 3 mm and a packing density of 1500 kg / m³. The temperature was controlled at 30℃ and the pressure at 0.15 MPa.

[0058] Result: The free bromine content decreased from the initial 500 ppm to 0 ppm.

[0059] 2. Preliminary removal of moisture:

[0060] The gas enters the primary drying tank, which is filled with liquid phosphorus tribromide with a density of 400 kg / m³. The temperature is controlled at 25°C, the flow rate at 2 m / s, and the pressure at 0.12 MPa. Phosphorus tribromide is replenished in real time to maintain the mass fraction of phosphorus tribromide at ≥85%.

[0061] Result: Moisture content decreased from the initial 3000 ppm to 253 ppm.

[0062] 3. Deep removal of trace amounts of water:

[0063] The gas enters a secondary drying tank, which is filled with 300 kg of strong acid cation exchange resin with an exchange capacity of 5.0 mmol / g and a particle size of 1.0 mm. The temperature is controlled at 25℃, the flow rate at 1.5 m / s, and the pressure at 0.10 MPa.

[0064] Result: Moisture content further decreased to 12 ppm.

[0065] 4. Mechanical impurity separation:

[0066] The treated gas is passed into a dust removal device to remove particles with a diameter >5μm, and then into a cyclone separator, with the gas inlet angle controlled at 90°, flow velocity at 0.8m / s, and centrifugal acceleration at 1000m / s². The treated gas is then passed into a condensation device, with a final liquefaction temperature of -20℃ and a heat exchange area of ​​16m², to liquefy hydrogen bromide. Finally, the gas is sent to a liquefied storage tank. The condensation device in S4 uses a two-stage series refrigeration system. The first stage uses an ethylene glycol aqueous solution as the refrigerant and the temperature is controlled at -3℃. The second stage uses liquid nitrogen circulation and the temperature is controlled at -20℃.

[0067] Results: The purity of hydrogen bromide reached 99.9%, and the content of mechanical impurities was ≤0.01%.

[0068] Example 2

[0069] 1. Removal of free bromine:

[0070] The gas is introduced into the primary bromine removal tank at a flow rate of 1.5 m / s, and is filled with 300 kg of red phosphorus with a particle size of 4 mm and a filling density of 1200 kg / m³. The temperature is controlled at 35℃ and the pressure at 0.18 MPa.

[0071] Result: The free bromine content decreased from 500 ppm to 0 ppm.

[0072] 2. Preliminary removal of moisture:

[0073] The gas enters the primary drying tank, which is filled with liquid phosphorus tribromide with a density of 200 kg / m³. The temperature is controlled at 30°C, the flow rate at 1.8 m / s, and the pressure at 0.15 MPa. Phosphorus tribromide is replenished in real time to maintain the mass fraction of phosphorus tribromide at ≥85%.

[0074] Result: Moisture content decreased from 3000 ppm to 251 ppm.

[0075] 3. Deep removal of trace amounts of water:

[0076] The gas enters the secondary drying tank, which is filled with 400 kg of mordenite zeolite with a silicon-aluminum molar ratio of 10:1, a pore size of 0.5 nm, a packing density of 400 kg / m³, and controlled at a temperature of 20 °C, a flow rate of 2.0 m / s, and a pressure of 0.12 MPa.

[0077] Result: Moisture content decreased to 14 ppm.

[0078] 4. Mechanical impurity separation:

[0079] The treated gas is passed into a dust removal device to remove particles larger than 5 μm, and then into a cyclone separator with the gas inlet angle controlled at 80°, flow rate at 0.5 m / s, and centrifugal acceleration at 500 m / s². The treated gas is then passed into a condensation device with a final liquefaction temperature of -15°C and a heat exchange area of ​​12 m² to liquefy hydrogen bromide, and finally sent to a liquefied storage tank. The condensation device uses a two-stage series refrigeration system. The first stage uses an ethylene glycol aqueous solution as the refrigerant and is controlled at -5°C. The second stage uses liquid nitrogen circulation and is controlled at -15°C.

[0080] Results: Hydrogen bromide purity was 99.9%, and mechanical impurity content was ≤0.01%.

[0081] Example 3

[0082] 1. Removal of free bromine:

[0083] The gas is introduced into the primary bromine removal tank at a flow rate of 2.5 m / s, and 400 kg of red phosphorus with a particle size of 2 mm and a packing density of 1800 kg / m³ is loaded. The temperature is controlled at 25℃ and the pressure at 0.10 MPa.

[0084] Result: The free bromine content decreased from 500 ppm to 0 ppm.

[0085] 2. Preliminary removal of moisture:

[0086] The gas enters the primary drying tank, which is filled with liquid phosphorus tribromide with a density of 600 kg / m³. The temperature is controlled at 40℃, the flow rate at 3.0 m / s, and the pressure at 0.20 MPa. Phosphorus tribromide is replenished in real time to maintain the mass fraction of phosphorus tribromide at ≥85%.

[0087] Result: Moisture content decreased from 3000 ppm to 240 ppm.

[0088] 3. Deep removal of trace amounts of water:

[0089] The secondary drying tank is filled with 500 kg of resin and mordenite mixed packing material in a mass ratio of 1:1. The resin exchange capacity is 4.8 mmol / g, the zeolite silica-alumina molar ratio is 20:1, and the temperature is controlled at 30℃, the flow rate is 0.8 m / s, and the pressure is 0.08 MPa.

[0090] Result: Moisture content decreased to 10 ppm.

[0091] 4. Mechanical impurity separation:

[0092] The treated gas is passed into a dust removal device to remove particles larger than 5 μm, then into a cyclone separator with the gas inlet angle controlled at 100°, flow rate at 1 m / s, and centrifugal acceleration at 1500 m / s². The treated gas is then passed into a condensation device with a final liquefaction temperature of -25°C and a heat exchange area of ​​18 m², liquefying hydrogen bromide before finally being sent to a liquefied storage tank. The condensation device employs a two-stage series refrigeration system: the first stage uses an ethylene glycol aqueous solution as the refrigerant, with the temperature controlled at 0°C; the second stage uses liquid nitrogen circulation, with the temperature controlled at -25°C.

[0093] Results: Hydrogen bromide purity was 99.9%, and mechanical impurity content was ≤0.01%.

[0094] Comparative Example 1

[0095] 1. Removal of free bromine: Same as in Example 1.

[0096] 2. Moisture removal: Only a primary drying tank filled with silica gel is used, with a filling of 300 kg, a temperature of 25℃, a flow rate of 2 m / s, and a pressure of 0.12 MPa.

[0097] 3. Steps for deep removal of water without leaving traces.

[0098] 4. Mechanical separation: Ordinary cyclone separator, without condensation device.

[0099] The test results are shown in Table 1:

[0100] Table 1

[0101]

[0102] As can be seen from the data in Table 1, Comparative Example 1, due to the lack of deep drying and cooling separation steps, has a significantly lower efficiency in removing moisture and impurities than Example 1.

[0103] Comparative Example 2

[0104] 1. Free bromine removal: Same as in Example 2, but no buffer tank is installed between the primary bromine removal tank and the primary drying tank.

[0105] 2. Preliminary removal of moisture: Liquid phosphorus tribromide was not replenished in time, and its mass fraction dropped to 60%.

[0106] 3. Trace water removal: Dew point meter was not used to adjust parameters.

[0107] The test results are shown in Table 2:

[0108] Table 2

[0109]

[0110] As can be seen from the data in Table 2, the comparative example 2 suffered from large process fluctuations and decreased drying efficiency due to the lack of a buffer tank and dynamic adjustment.

[0111] Experimental standards and parameter optimization basis

[0112] 1. Testing Standards:

[0113] Free bromine content: GB / T1600-2001 (iodometric method);

[0114] Moisture content: GB / T6283-2008 (Karl Fischer method);

[0115] Mechanical impurity content: GB / T13277.1-2008 (gravimetric method);

[0116] Hydrogen bromide purity: Gas chromatography (ASTM D4626);

[0117] Pressure differential fluctuation in drying tank: GB / T1226-2017 (Dynamic pressure recording);

[0118] Process stability: ISO22514-3:2008 (Statistical Process Control).

[0119] 2. Basis for parameter optimization:

[0120] Red phosphorus particle size (2-5mm): If the particle size is too small (<2mm), the porosity between particles decreases, leading to an increase in bed pressure difference. This can easily cause dense accumulation at the bottom sieve plate of the adsorption tank, resulting in local blockage of the gas flow channel. If the particle size is too large (>5mm), the specific surface area decreases significantly, and the free bromine adsorption efficiency decreases by more than 20%.

[0121] Phosphorus tribromide mass fraction ≥85%: below this value will cause a sharp drop in water removal rate (experimental verification);

[0122] Centrifugal acceleration of cyclone separator (500-1500m / s²): Too low an acceleration will result in incomplete separation of impurities, while too high an acceleration will result in a sharp increase in energy consumption.

[0123] 3. Verification of implementation results:

[0124] By comparing Examples 1 to 3 with Comparative Examples 1 and 2, this invention significantly improves the purification efficiency (purity ≥ 99.9%) and process stability of hydrogen bromide through a multi-stage controlled process (red phosphorus adsorption → phosphorus tribromide reaction → resin / zeolite adsorption → cyclone cooling separation) and a dynamic compensation mechanism (buffer tank, dew point feedback), making it suitable for the industrial production of high-purity electronic-grade hydrogen bromide gas.

[0125] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for purifying hydrogen bromide by removing bromine, water, and impurities before liquefaction, characterized in that, Includes the following steps: S1. Removal of free bromine: Hydrogen bromide gas is passed into a primary bromine removal tank filled with red phosphorus packing material; The packing density of red phosphorus in S1 is 1200-1800 kg / m³, and the particle size is 2-5 mm; S2, Preliminary removal of moisture: The gas treated by S1 is passed into a primary drying tank filled with liquid phosphorus tribromide. The mass concentration of liquid phosphorus tribromide in S2 is 200-600 kg / m³, and phosphorus tribromide is replenished in real time during the reaction to maintain the mass fraction of phosphorus tribromide ≥85%. S3, Deep removal of trace water: The gas treated by S2 is passed into a secondary drying tank filled with mordenite zeolite. The silica-alumina molar ratio of the mordenite in S3 is (10-20):1, the pore size is 0.4-0.7 nm, and the packing density is 300-500 kg / m³. S4. Separation of mechanical impurities: The gas treated in S3 is passed into a dust removal device to remove particles with a diameter >5μm, and then into a cyclone separator. The gas inlet angle is controlled at 80-100°, the flow rate is 0.5-1m / s, and the centrifugal acceleration is 500-1500m / s². The treated gas is then passed into a condensation device with a final liquefaction temperature of -25~-15℃ and a heat exchange area of ​​12-18m² to liquefy hydrogen bromide. Finally, the gas is sent to a liquefied storage tank. The ratio of the cylinder height to the diameter of the cyclone separator in S4 is 3:1-5:1, and the width of the gas inlet is 1 / 5-1 / 3 of the cylinder diameter; The condensation device in S4 employs a two-stage series refrigeration system. The first stage uses an ethylene glycol aqueous solution as the refrigerant, with the temperature controlled between -5 and 0°C. The second stage uses liquid nitrogen circulation, with the temperature controlled between -25 and -15°C. A gas buffer tank is provided between the primary bromine removal tank and the primary drying tank. A dew point detector is provided at the outlet of the secondary drying tank. The inner wall of the gas pipeline connecting the primary bromine removal tank, the primary drying tank, the secondary drying tank and the cyclone separator is coated with polytetrafluoroethylene. The polytetrafluoroethylene coating has a roughness Ra≤0.8μm and a thickness of 50-100μm. The gas pipeline is backflushed with 0.3-0.5MPa nitrogen every 2-4 hours.

2. The method for purifying hydrogen bromide by removing bromine, water, and impurities before liquefaction according to claim 1, characterized in that: The pressure fluctuation range of the gas buffer tank is ≤±5%, and the gas residence time is 10-30s.

3. The method for purifying hydrogen bromide by removing bromine, water, and impurities before liquefaction according to claim 1, characterized in that: The dew point detector monitors the gas dew point in real time (≤-60℃) and dynamically adjusts the temperature and gas flow rate of the secondary drying tank based on the detection results.

4. The method for purifying hydrogen bromide by removing bromine, water, and impurities before liquefaction according to claim 1, characterized in that: The bottom of the cyclone separator in S4 is equipped with a vibrating screening device with a screen mesh size of 100-200 mesh, a vibration frequency of 20-50Hz, and an amplitude of 1-3mm.

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