A method and system for purifying hydrogen peroxide

Abstract

This invention relates to the field of hydrogen peroxide production technology, and more particularly to a method and system for purifying hydrogen peroxide. The purification method includes: introducing an initial hydrogen peroxide solution with a concentration of 20-35% into a distillation column; sending the water vapor distilled from the top of the distillation column into the tube side of a first heat exchanger for condensation, with the resulting liquid water being input into a cold water tank and partially returned to the distillation column; the refrigerant in the shell side of the first heat exchanger absorbing heat and evaporating then entering the shell side of a falling film heat exchanger, providing a reboiling heat source for the purified hydrogen peroxide with a concentration of 50-70% output from the bottom of the distillation column to the tube side of the falling film heat exchanger, causing partial evaporation that returns to the distillation column to provide rising steam, while the unevaporated portion is output as product; when the system triggers a safety interlock condition, an emergency valve located between the cold water tank and the tube side of the falling film heat exchanger is opened to achieve rapid cooling and dilution. This method achieves low energy consumption and intrinsic safety while ensuring high product purity.

Description

Technical Field

[0001] This invention relates to the field of hydrogen peroxide production technology, and in particular to a method and system for purifying hydrogen peroxide. Background Technology

[0002] Hydrogen peroxide (H2O2), as an important inorganic chemical product, is widely used in chemical, pharmaceutical, and environmental protection fields, and its purity directly affects its effectiveness. Currently, the mainstream industrial technology for purifying hydrogen peroxide is vacuum distillation. This technology lowers the boiling point of the material by reducing the system pressure, thus separating it at a relatively low temperature to avoid the violent decomposition of hydrogen peroxide at high temperatures. To further reduce energy consumption, mechanical vapor recompression (MVR) technology has also been introduced. This technology uses a compressor to heat and pressurize the vapor at the top of the column, using it as a heat source for the reboiler at the bottom, significantly reducing the consumption of fresh steam and greatly improving economic efficiency.

[0003] However, these existing technologies suffer from a fundamental and irreconcilable problem: the contradiction between safety and purity. Specifically, hydrogen peroxide is a strong oxidizing agent and unstable, easily decomposing under conditions of high temperature and impurity catalysis, releasing oxygen and accompanied by a sudden increase in temperature and pressure. Improper control could lead to safety accidents. Furthermore, higher purity results in higher instability. In MVR systems, the high-speed rotating compressor impeller inevitably produces substances such as Fe... 2+ Ni 2+ Metal shavings and other metal ions act as highly efficient catalysts for the decomposition of hydrogen peroxide. Once they enter the system, they drastically accelerate the decomposition of hydrogen peroxide, leading to anything from decreased product concentration and excessive impurities to serious accidents such as boiling over and explosions. To address such runaway reactions, the system needs safety emergency measures. However, traditional emergency solutions often rely on conventional control systems, resulting in delayed cooling and dilution measures in emergencies. While injecting external cooling water for cooling and dilution is effective, it introduces new metal ion impurities such as calcium and magnesium, contaminating the entire system and completely destroying the quality of subsequent high-purity products.

[0004] Therefore, achieving low energy consumption and inherent safety while ensuring high product purity has become a key issue that urgently needs to be addressed in current hydrogen peroxide purification processes.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the present invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The technical problem this invention aims to solve is to provide a hydrogen peroxide purification method that does not use MVR technology but employs distillation and an innovative refrigerant cycle thermal integration method to purify the initial hydrogen peroxide solution to 50-70%. The entire system's cooling capacity is provided by a closed-loop refrigerant refrigeration cycle. The water source for the cooling tank is entirely pure water condensed from the top of the distillation column, with no metal ions introduced, completely avoiding the risks of metal ion contamination and catalytic decomposition that may arise from external cooling water.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for purifying hydrogen peroxide includes the following steps:

[0009] S1 introduces an initial hydrogen peroxide solution with a concentration of 20-35% into a distillation column for separation;

[0010] Furthermore, in step S1, the separation temperature inside the distillation column is 50-68℃. When the system is started for the first time or restarted after a long shutdown, the initial hydrogen peroxide solution (20-35%) in the distillation column bottom is at room temperature and cannot establish normal boiling and reflux. At this time, the inlet valves of the tube side and shell side of the standby heat exchanger are opened, and the opening of the regulating valve is controlled to send liquid water from the cold water tank into the tube side of the standby heat exchanger at a set flow rate. The external steam source valve is controlled to introduce external steam into the shell side of the standby heat exchanger. The standby heat exchanger uses the heat of the external steam to convert the liquid water in its tube side into clean steam, which is used to heat the initial hydrogen peroxide solution in the distillation column. During the process, the bottom temperature is monitored. When the bottom temperature rises to the stable operating temperature range, the main process is started. After the main process stabilizes, the inlet valves of the shell side and tube side of the standby heat exchanger are closed in sequence to isolate it from the system.

[0011] Furthermore, in step S1, the liquid water in the spare heat exchanger tube side is either the liquid water from the previous batch of cold water tank or high-purity water free of any metal ions and organic matter, thus preventing the introduction of metal ions and organic matter at the source. This avoids contamination of hydrogen peroxide by impurities, ensures product purity, eliminates the risk of metal ions catalyzing the decomposition of hydrogen peroxide, reduces safety hazards, and adapts to the purification needs of hydrogen peroxide at multiple concentrations.

[0012] S2 sends the water vapor distilled from the top of the distillation column to the tube side of the first heat exchanger for condensation. The resulting liquid water is fed into the cold water tank and partially returned to the distillation column, while the remainder is stored in the cold water tank.

[0013] Furthermore, in step S2, the top of the distillation column distills off a component mainly consisting of water vapor at a lower temperature, with the water vapor temperature being 26-30°C. This water vapor enters the tube side of the first heat exchanger and is condensed into liquid water at ≤10°C by the refrigerant in the shell side of the first heat exchanger. A portion of the liquid water is returned to the top of the distillation column as reflux liquid to maintain the operation inside the column, while the remaining condensate is collected and stored.

[0014] Furthermore, the cold water tank adopts a double-layer vacuum insulation structure. The cold water tank is not only a process water tank but also a dedicated safety buffer storage tank. The liquid water in the cold water tank is pure water condensed from the top of the distillation column, free of exogenous metal ions and other organic matter. The temperature of the liquid water in the cold water tank is maintained below 10°C, and the liquid water is the only cold source used for process cooling in step S4.

[0015] The refrigerant in the shell side of the first heat exchanger of S3 absorbs heat and evaporates, then enters the shell side of the falling film heat exchanger and condenses and releases heat. This provides a reboiling heat source for the purified hydrogen peroxide with a concentration of 50-70% that is output from the bottom of the distillation column to the tube side of the falling film heat exchanger, causing part of it to evaporate and return to the distillation column to provide rising steam, while the unevaporated part is output as product.

[0016] In this process, the high-temperature, high-concentration purified hydrogen peroxide output from the bottom of the distillation column enters the tube side of the falling film heat exchanger, absorbing the heat released by the condensation of the refrigerant in the shell side of the falling film heat exchanger. That is, the shell side temperature of the falling film heat exchanger is higher than the tube side temperature. After absorbing heat, some of the hydrogen peroxide evaporates, and the generated vapor is drawn back to the bottom of the distillation column as the source of rising vapor in the column. The unevaporated hydrogen peroxide with the required concentration is output as the final product. Specifically, the temperature difference between the shell side and the tube side in the falling film heat exchanger is 3-15℃, the temperature of the hydrogen peroxide output from the bottom of the distillation column is 50-68℃, and the temperature of the refrigerant entering the shell side of the falling film heat exchanger is 55-80℃.

[0017] In this invention, the falling film heat exchanger, as the core component of the "heat pump," utilizes refrigerant to transfer the low-temperature heat that needs to be removed from the top of the tower and releases it at a higher temperature, providing heat for the partial evaporation of hydrogen peroxide at the bottom of the tower. This significantly reduces the net energy consumption of the entire process.

[0018] Furthermore, in step S3, after the refrigerant absorbs heat and evaporates, it all enters the shell side of the falling film heat exchanger. The excess refrigerant that is not completely condensed in the shell side of the falling film heat exchanger enters the auxiliary condenser and is completely condensed before returning to the first heat exchanger for recycling.

[0019] Furthermore, the refrigerant is either a Freon-based refrigerant or a hydrocarbon-based refrigerant.

[0020] The S4 system is equipped with a safety monitoring device that monitors changes in the hydrogen peroxide system in real time. When the system triggers a safety interlock condition, an emergency valve located between the cold water tank and the tube side of the falling film heat exchanger is opened. This injects condensate stored in the cold water tank into the material flow of the falling film heat exchanger tube side. The cold water directly lowers the material temperature and dilutes the hydrogen peroxide concentration, rapidly reducing the risk of decomposition and ensuring system safety. After the emergency valve opens, the chiller supplying refrigerant to the shell side of the first heat exchanger is shut off, cutting off the heat source for the falling film heat exchanger. Simultaneously, reflux operation from the cold water tank to the top of the distillation column is maintained. Closing the emergency valve requires confirmation of system safety; for example, the valve should only be closed after the hydrogen peroxide concentration has been diluted to <40% and the temperature <45°C.

[0021] Furthermore, in step S4, the safety interlock condition is: the emergency valve is immediately opened when any of the following conditions are met:

[0022] a. The rate of increase in dissolved O2 concentration is ≥0.1 ppm / s;

[0023] b. Temperature change rate ≥ 0.5℃ / min;

[0024] c. Actual temperature ≥ dynamic safety threshold;

[0025] d. Pressure change rate ≥ 0.1 MPa / min;

[0026] e. Absolute pressure ≥ safe pressure limit.

[0027] The dynamic safety threshold is set as the theoretical self-accelerating decomposition temperature at the current concentration minus 10-15℃; the safety pressure limit is 90% of the design pressure of the falling film heat exchanger. It should be noted that the self-accelerating decomposition process of hydrogen peroxide is significantly affected by pH value, metal ion concentration (especially iron and copper), solid catalyst, pressure, and the heat transfer performance of the equipment. In this invention, the entire system does not introduce metal ions, organic matter, or other catalytically active substances, thus maintaining a high self-accelerating decomposition temperature.

[0028] Furthermore, when the rate of increase of dissolved O2 concentration at the tube outlet of the falling film heat exchanger increases slightly or when various parameters are abnormal but do not reach the limit, the refrigerant flow rate is automatically increased to reduce the heating at the bottom of the tower.

[0029] Furthermore, after water injection is performed in step S4, the system automatically shuts off the feed to the distillation column.

[0030] The second objective of this invention is to provide a hydrogen peroxide purification system that, while ensuring high product purity, also achieves low energy consumption and intrinsic safety.

[0031] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0032] A hydrogen peroxide purification system includes a distillation column, a first heat exchanger, a cold water tank, a falling film heat exchanger, a standby heat exchanger, and an auxiliary condenser.

[0033] The top outlet of the distillation column is connected to the tube-side inlet of the first heat exchanger, and the tube-side outlet of the first heat exchanger is connected to the cold water tank. The cold water tank is equipped with two outlets, which are respectively connected to the top reflux port of the distillation column and the tube-side inlet of the falling film heat exchanger. An emergency valve is installed between the cold water tank and the tube-side of the falling film heat exchanger.

[0034] The bottom outlet of the distillation column is connected to the tube-side inlet of the falling film heat exchanger; the tube-side outlet of the falling film heat exchanger is connected to the hydrogen peroxide concentration storage tank; and the tube-side vapor outlet of the falling film heat exchanger is connected to the reflux port at the bottom of the distillation column.

[0035] The shell-side outlet of the first heat exchanger is connected to the shell-side inlet of the falling film heat exchanger, and a chiller is installed on its circuit. The shell-side outlet of the falling film heat exchanger is connected to the feed port of the auxiliary condenser and the shell-side inlet of the first heat exchanger, respectively. The discharge port of the auxiliary condenser is connected to the shell-side inlet of the first heat exchanger.

[0036] The tube-side inlet of the standby heat exchanger is connected to a cold water tank and is equipped with a regulating valve and a shut-off valve; the tube-side outlet is connected to the bottom of the distillation column; the shell-side inlet is connected to an external steam source; and the shell-side outlet is connected to a condensate recovery system.

[0037] Furthermore, the tube-side outlet of the falling film heat exchanger is equipped with a TDLAS sensor, a temperature sensor, and a pressure sensor to monitor the rate of increase in dissolved O2 concentration and the system temperature / pressure changes in real time. All sensor signals are connected to an independent safety instrument system, and the action delay of triggering the emergency valve is <100ms.

[0038] Furthermore, the standby heat exchanger is only put into use during the system startup phase; when the temperature at the bottom of the distillation column reaches 50-68℃ and a stable reflux is established at the top of the column, the heat source is switched to the falling film heat exchanger, and the standby heat exchanger is isolated.

[0039] The beneficial effects of this invention are as follows:

[0040] This invention innovatively employs a refrigerant circulation system to directly convert the waste heat at the top of the tower, which originally needed to be removed through an external cold source, into the heat energy required for reboiling at the bottom of the tower. This forms an energy closed loop within the system, successfully replacing traditional MVR technology or external steam heating. While achieving efficient energy integration and recycling and significantly reducing energy consumption, it completely avoids the risk of metal shavings contamination caused by MVR compressors.

[0041] This invention utilizes the pure water condensed at the top of the distillation column as the sole emergency cooling source and diluent, fundamentally eliminating potential metal ion contamination from external cooling water or other media. This eliminates the primary cause of catalytic decomposition at its source, ensuring high product purity and the system's inherent safety. Furthermore, by directly integrating a safety interlock mechanism into the critical heat and mass transfer process of falling film heat exchange and employing its own pure water for millisecond-level emergency response, rapid cooling and dilution are achieved without introducing any secondary contamination, resulting in a truly intrinsically safe design. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a process flow diagram of the hydrogen peroxide purification method in this invention;

[0044] Figure 2 Flowchart of the safety monitoring device response;

[0045] Figure 3 This is a schematic diagram of the hydrogen peroxide purification system in this invention.

[0046] Reference numerals: 11. Distillation column; 12. First heat exchanger; 13. Cold water tank; 14. Falling film heat exchanger; 15. Standby heat exchanger; 16. Auxiliary condenser; 17. Emergency valve; 18. Regulating valve and shut-off valve; 19. Sensor group. Detailed Implementation

[0047] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0049] like Figure 1 The hydrogen peroxide purification method provided by this invention includes the following steps:

[0050] S1 introduces an initial hydrogen peroxide solution with a concentration of 20-35% into a distillation column for separation at a temperature of 50-68℃. This invention is based on the difference in boiling points between hydrogen peroxide and water, and achieves the separation of hydrogen peroxide and water through a distillation column.

[0051] When the system is first started up or restarted after a long shutdown, the initial hydrogen peroxide solution (20-35%) in the distillation column reboiler is at room temperature, which cannot establish normal boiling and reflux. At this time, the inlet valves of the standby heat exchanger's tube side and shell side are opened, and the opening of the regulating valve is controlled to send liquid water from the cold water tank into the tube side of the standby heat exchanger at a set flow rate. The external steam source valve is controlled to introduce external steam into the shell side of the standby heat exchanger. The standby heat exchanger uses the heat of the external steam to convert the liquid water in its tube side into clean steam, which is used to heat the initial hydrogen peroxide solution in the distillation column. During this process, the reboiler temperature is monitored. When the reboiler temperature rises to the stable operating temperature range, the main process is started. After the main process stabilizes, the inlet valves of the standby heat exchanger's shell side and tube side are closed sequentially to isolate it from the system, further reducing overall energy consumption. This invention, through the switching between the standby heat exchanger and the falling film heat exchanger, ensures a smooth transition of the distillation column from start-up to stable operation, maintaining separation efficiency. Specifically, the liquid water in the spare heat exchanger tube side is either the liquid water from the previous batch of cold water tank or high-purity water that contains no metal ions and no organic matter.

[0052] The top of the S2 distillation column distills off a component mainly composed of water vapor at a relatively low temperature, with the water vapor temperature being 26-30℃. This water vapor enters the tube side of the first heat exchanger, where it is condensed into liquid water at ≤10℃ by the refrigerant in the shell side. The resulting liquid water is fed into a cold water tank, and a portion of it is returned to the top of the distillation column as reflux to maintain column operation. The remaining condensate is collected and stored. Low-temperature distillation and condensation reduce the decomposition of hydrogen peroxide at high temperatures, ensuring product yield and safety. The partial reflux of condensate maintains the gas-liquid balance and separation accuracy within the distillation column, ensuring a stable hydrogen peroxide concentration at the bottom. The remaining condensate, collected and stored in the cold water tank, can serve as a water source for subsequent backup heat exchangers, achieving water resource recycling, reducing the cost of high-purity water consumption, and preventing the introduction of impurities that could affect system operation.

[0053] The cold water tank employs a double-layer vacuum insulation structure to reduce external heat transfer and maintain the low temperature of the liquid water. The cold water tank is not only a process water tank but also a dedicated safety buffer storage tank. The liquid water in the cold water tank is pure water condensed from the top of the distillation column, free of exogenous metal ions and other organic matter. The water temperature in the cold water tank is maintained below 10°C. This low-temperature characteristic gives it a stronger cooling capacity when used as an emergency cooling source. The liquid water is the only cooling source used for process cooling in step S4.

[0054] The refrigerant in the shell side of the first heat exchanger of S3 absorbs heat and evaporates, then enters the shell side of the falling film heat exchanger and condenses and releases heat. This provides a reboiling heat source for the purified hydrogen peroxide with a concentration of 50-70% that is output from the bottom of the distillation column to the tube side of the falling film heat exchanger, causing part of it to evaporate and return to the distillation column to provide rising steam, while the unevaporated part is output as product.

[0055] In this process, the high-temperature, high-concentration purified hydrogen peroxide output from the bottom of the distillation column enters the tube side of the falling film heat exchanger, absorbing the heat released by the condensation of the refrigerant in the shell side of the heat exchanger. This means the shell side temperature of the falling film heat exchanger is higher than the tube side temperature. After absorbing heat, some of the hydrogen peroxide evaporates, and the resulting vapor is drawn back to the bottom of the distillation column as the source of rising vapor within the column. The unevaporated hydrogen peroxide, meeting the required concentration, is output as the final product. Specifically, the temperature difference between the shell side and the tube side of the falling film heat exchanger is 3-15℃ to avoid excessive temperature difference leading to localized overheating of the hydrogen peroxide. The temperature of the hydrogen peroxide output from the bottom of the distillation column is 50-68℃. The temperature of the refrigerant entering the shell side of the falling film heat exchanger is 55-80℃, which satisfies the heat required for the reboiling of the hydrogen peroxide while preventing excessively high temperatures from causing decomposition.

[0056] In this invention, the falling film heat exchanger, as the core component of the "heat pump," utilizes the refrigerant to transfer the low-temperature heat that needs to be removed from the top of the tower and releases it at a higher temperature, providing heat for the partial evaporation of hydrogen peroxide at the bottom of the tower. This significantly reduces the net energy consumption of the entire process. After the refrigerant absorbs heat and evaporates, it all enters the shell side of the falling film heat exchanger. After the falling film heat exchanger is used, the excess portion is processed by an auxiliary condenser to ensure efficient refrigerant circulation. The condensed refrigerant returns to the shell side of the first heat exchanger for reuse.

[0057] Specifically, the refrigerant is either a Freon-based or a hydrocarbon-based refrigerant. Freon-based refrigerants, such as R134a, R410A, and R32, are commonly used in industrial refrigeration. They are highly stable, non-flammable, and their refrigeration efficiency is suitable for water vapor condensation conditions at 26-30℃. Their phase change temperature and pressure are easily controlled, and they can stably condense water vapor to ≤10℃. They also have low corrosivity to system metal components and strong operational safety. Hydrocarbon-based refrigerants, such as propane (R290), isobutane (R600a), and propylene (R1270), are mostly natural hydrocarbons. They are environmentally friendly, have high thermal conductivity, high condensation heat exchange efficiency, and are widely available and relatively inexpensive.

[0058] The S4 system is equipped with a safety monitoring device that monitors changes in the hydrogen peroxide system in real time, such as... Figure 2When the system triggers the safety interlock condition, the emergency valve located between the cold water tank and the tube side of the falling film heat exchanger is opened. This injects condensate stored in the cold water tank into the material flow of the falling film heat exchanger tube side. The cold water directly lowers the material temperature and dilutes the hydrogen peroxide concentration, rapidly reducing its decomposition risk and ensuring system safety. After the emergency valve opens, the chiller supplying refrigerant to the shell side of the first heat exchanger is shut off, cutting off the heat source for the falling film heat exchanger and automatically closing the feed to the distillation column. Simultaneously, reflux operation from the cold water tank to the top of the distillation column is maintained. Closing the emergency valve requires confirmation of system safety; for example, the valve should only be closed after the hydrogen peroxide concentration has been diluted to <40% and the temperature <45°C.

[0059] After water injection is performed in step S4, the system automatically shuts off the feed to the distillation column and cuts off the heat source to the falling film heat exchanger. This prevents the continuous input of the material to be treated from causing further accumulation of risks within the abnormal system; cutting off the heat source to the falling film heat exchanger directly terminates the external energy input, fundamentally suppressing the core cause of hydrogen peroxide decomposition due to heating. These two measures simultaneously prevent the risk from escalating and avoid its compounding.

[0060] The chilled water used is the condensate from within the system, eliminating the need for additional emergency water reserves. It is compatible with the closed-loop design of the purification system, and the water is clean and free of impurities, avoiding the introduction of new risks. At the same time, it is quickly injected into the tube side of the falling film heat exchanger, directly acting on the material flow, resulting in a faster risk control response.

[0061] The safety interlock condition is as follows: the emergency valve will be opened immediately when any of the following conditions are met:

[0062] a. The rate of increase in dissolved O2 concentration is ≥0.1 ppm / s;

[0063] b. Temperature change rate ≥ 0.5℃ / min;

[0064] c. Actual temperature ≥ dynamic safety threshold; the dynamic safety threshold is set as the theoretical self-accelerating decomposition temperature at the current concentration minus 10-15℃.

[0065] d. Pressure change rate ≥ 0.1 MPa / min;

[0066] e. Absolute pressure ≥ safe pressure limit. The safe pressure limit is 90% of the design pressure of the falling film heat exchanger.

[0067] The decomposition of hydrogen peroxide is a complex, autocatalytic, and exothermic process. Its autoaccelerated decomposition temperature refers to the lowest ambient temperature at which, under specific packaging and conditions, the rate of internal heat generation exceeds the rate of heat dissipation, leading to a spontaneous temperature rise and ultimately uncontrolled decomposition. The decomposition rate of hydrogen peroxide increases with concentration; different concentrations correspond to different theoretical autoaccelerated decomposition temperatures. The higher the concentration, the lower the decomposition temperature. The dynamic safety threshold is set at the theoretical autoaccelerated decomposition temperature minus 10-15°C, providing a safety buffer zone to prevent the actual decomposition temperature from being reached. The safety pressure limit is set at 90% of the design pressure of the falling film heat exchanger to prevent overpressure damage and leakage.

[0068] The self-accelerating decomposition process of hydrogen peroxide is significantly affected by pH value, metal ion concentration (especially iron and copper), solid catalyst, pressure, and the heat transfer performance of the equipment. In this invention, the entire system does not introduce metal ions, organic matter, or other substances with catalytic effects, and can maintain a high self-accelerating decomposition temperature.

[0069] It is important to note that the accelerated decomposition of hydrogen peroxide, once initiated, is highly exothermic. The release of O2, heat, and gases causes an increase in dissolved O2 concentration, temperature, and pressure; these abnormal changes are early signs of intensified decomposition. The established safety interlock conditions directly correspond to the key characteristics of the decomposition reaction, triggering emergency measures before the danger escalates. This invention sets interlock conditions from three core dimensions: dissolved oxygen, temperature, and pressure, using multi-parameter fusion to determine decomposition signals. It covers the precursors and critical states of hydrogen peroxide decomposition, eliminating monitoring blind spots and avoiding misjudgments or omissions based on a single indicator. Simultaneously, the system utilizes its own generated ultrapure cold water to physically cool and chemically dilute the hazardous sites within milliseconds, interrupting the self-accelerating chain.

[0070] When the rate of increase in dissolved O2 concentration at the tube outlet of the falling film heat exchanger slightly rises, or when various parameters are abnormal but do not reach the limit, the refrigerant flow rate is automatically increased to reduce the heating load at the bottom of the tower. This prevents the problem from accumulating to the point of triggering emergency injection and reduces the impact on system stability.

[0071] like Figure 3 As shown, a hydrogen peroxide purification system includes a distillation column 11, a first heat exchanger 12, a cold water tank 13, a falling film heat exchanger 14, a standby heat exchanger 15, and an auxiliary condenser 16.

[0072] The top outlet of the distillation column 11 is connected to the tube-side inlet of the first heat exchanger 12, and the tube-side outlet of the first heat exchanger 12 is connected to the cold water tank 13. The cold water tank 13 is provided with two outlets, which are respectively connected to the top reflux port of the distillation column 11 and the tube-side inlet of the falling film heat exchanger 14. The top reflux ratio of the distillation column 11 is controlled at 3:1, which can ensure sufficient contact between the reflux liquid and the rising vapor at the top of the column, enhance the gas-liquid mass transfer effect, improve the separation and purification accuracy of hydrogen peroxide, and maintain the consistency of the operating conditions in the distillation column 11 through stable reflux ratio control, so as to avoid unstable purification quality due to reflux fluctuations. An emergency valve 17 is installed between the tube side of the cold water tank 13 and the falling film heat exchanger 14. During normal operation, the cold water tank 13 mainly serves the reflux from the distillation column 11, ensuring the purification process. When the safety interlock is triggered, the emergency valve 17 opens, while the valve controlling the reflux remains open. The cold water tank 13 immediately switches to the "emergency water source," and the switching process is completed using existing pipelines without the need for additional adjustments to the material path. This avoids resource waste caused by the idle emergency device and ensures the stability of the system during the switch.

[0073] The bottom outlet of the distillation column 11 is connected to the tube-side inlet of the falling film heat exchanger 14; the tube-side outlet of the falling film heat exchanger 14 is connected to the hydrogen peroxide concentration storage tank, and the tube-side vapor outlet of the falling film heat exchanger 14 is connected to the reflux port at the bottom of the distillation column 11; the vapor generated by the hydrogen peroxide material in the tube side of the falling film heat exchanger 14 is refluxed back to the bottom of the distillation column 11 through the pipeline, and the residual heat of the vapor is used to provide some heat to the bottom of the distillation column 11 to help maintain the distillation temperature at the bottom of the column; after the vapor is condensed, it can be integrated into the material at the bottom of the column to replenish the liquid phase components in the column.

[0074] The shell-side outlet of the first heat exchanger 12 is connected to the shell-side inlet of the falling film heat exchanger 14, and a chiller is installed on its circuit to prioritize the heat dissipation needs of the falling film heat exchanger 14. The shell-side outlet of the falling film heat exchanger 14 is connected to the feed port of the auxiliary condenser 16 and the shell-side inlet of the first heat exchanger 12, respectively. The discharge port of the auxiliary condenser 16 is connected to the shell-side inlet of the first heat exchanger 12.

[0075] After the cooling medium flows out from the shell-side outlet of the first heat exchanger 12, it undergoes heat exchange in the falling film heat exchanger 14 and then flows back to the shell-side inlet of the first heat exchanger 12, forming a closed loop. Excess heat after being processed by the falling film heat exchanger enters the auxiliary condenser, condenses, and then flows back to the shell-side inlet of the first heat exchanger 12, forming a closed loop. During this cycle, the temperature gradient of the cooling medium is more stable, reducing temperature fluctuations in the shell-side of the first heat exchanger 12. This indirectly ensures the condensation effect of the gas exiting the distillation column 11 within its tube side, preventing liquid impurities from being carried into the gas due to insufficient cooling.

[0076] The standby heat exchanger 15 has its tube-side inlet connected to the cold water tank 13 and equipped with a regulating valve and a shut-off valve, while its tube-side outlet is connected to the bottom of the distillation column 11. Its shell-side inlet is connected to an external steam source, and its shell-side outlet is connected to a condensate recovery system. The standby heat exchanger 15 is only activated during the startup phase. Once the main process is stable, it can be completely isolated by closing the shell-side and tube-side inlet valves. This eliminates the need for long-term operation, avoids ineffective circulation of cold water and steam, reduces long-term operating losses of pumps and valves, and lowers electricity and steam costs associated with continuous equipment operation, thus reducing the overall energy consumption cost of the system.

[0077] Specifically, the distillation column 11 can be made of stainless steel, such as 316L, with corrugated packing inside. A level gauge is installed at the bottom of the column, and a temperature sensor is installed at the top. The first heat exchanger 12 can be designed as a shell-and-tube structure, with the tube side made of polytetrafluoroethylene to avoid metal ion contamination, and the shell side filled with refrigerant. The cold water tank 13 has a double-layer vacuum insulation structure with polished inner walls to reduce impurity adhesion. A temperature sensor and a level sensor are installed inside the tank. The falling film heat exchanger 14 has 316L stainless steel tubes, and a sensor group 19 is installed at the tube outlet. Specifically, it includes a TDLAS sensor with a detection accuracy of 0.01ppm, a temperature sensor with a detection accuracy of ±0.1℃, and a pressure sensor with a detection accuracy of ±0.001MPa installed in sequence. The TDLAS sensor monitors the dissolved O2 concentration in real time, and the temperature / pressure sensors track changes in the physical parameters of the system. All sensor signals are connected to an independent safety instrument system to avoid interference with the conventional control system. The action delay of the emergency valve 17 is <100ms.

[0078] The tube side of the standby heat exchanger 15 can be made of polytetrafluoroethylene, and it is equipped with a regulating valve and a shut-off valve 18. The standby heat exchanger 15 is only put into use during the system startup phase. When the bottom temperature of the distillation column 11 reaches 50-68℃ and a stable reflux is established at the top of the column, the heat source is switched to the falling film heat exchanger 14, and the standby heat exchanger 15 is isolated.

[0079] The auxiliary condenser 16 can be designed as a shell-and-tube structure, such as a horizontal heat exchanger, forming a closed loop with the shell side of the falling film heat exchanger 14, and is equipped with a refrigerant circulation pump. The emergency valve 17 can be a pneumatic ball valve with a response time of <50ms, and is directly linked to the independent safety instrumented system (SIS). All system components form a closed loop: the distillation column 11 separates the gas-liquid mixture; the first heat exchanger 12 achieves heat recovery and condensation; the cold water tank 13 stores the emergency medium and provides reflux; the falling film heat exchanger 14 completes reboiling and product output; the standby heat exchanger 15 ensures startup; and the auxiliary condenser 16 balances the refrigerant circulation. The emergency valve 17 connects the cold water tank 13 and the falling film heat exchanger 14, ensuring that the emergency medium directly acts on the high-risk area.

[0080] Example 1 (Hydrogen peroxide concentration at the bottom of the tower: 50%):

[0081] The operating procedure for the hydrogen peroxide purification system with the above-described pipeline connections is as follows:

[0082] Introduce an initial hydrogen peroxide solution with a concentration of 30% into the distillation column at a feed rate of 10,000 kg / h, and maintain the liquid level at 1.2 m. Check the cold water tank to ensure that it contains liquid water at ≤10℃ left over from the previous batch, and maintain the liquid level at 50%. Close the emergency valve and turn on the auxiliary condenser and refrigerant circulation pump to allow the refrigerant to circulate initially in the shell side of the first heat exchanger.

[0083] Turn on the external steam source for the shell side of the standby heat exchanger, and stabilize the steam pressure at 0.6 MPa. At the same time, slowly open the regulating valve and shut-off valve for the tube side of the standby heat exchanger to allow liquid water from the cold water tank to enter the tube side. After absorbing the heat from the steam, the liquid water is converted into clean steam at a temperature of about 105°C, which is then introduced into the bottom of the distillation column to heat the initial hydrogen peroxide solution. By controlling the steam flow rate through the regulating valve, the temperature at the bottom of the distillation column rises to 46.4°C at a rate of 1°C / min, the temperature at the top of the column gradually rises to 28.7°C, and the pressure at the top of the column stabilizes at 4 kPa.

[0084] The reflux at the top of the distillation column is continuously monitored. When the top temperature stabilizes at 28.7℃ and the top pressure at 4kPa, and a stable reflux (reflux flow rate of 10807kg / h) is observed at the top through the sight glass, the system is considered to have entered a stable state. At this time, the steam source of the shell side of the standby heat exchanger is shut off, the regulating valve and shut-off valve of the tube side are cut off, and the standby heat exchanger is isolated. At the same time, the refrigerant at the shell side outlet of the first heat exchanger is adjusted to enter the shell side of the falling film heat exchanger. The remaining refrigerant processed by the falling film heat exchanger is then processed by the auxiliary condenser, completing the switch from external heating to internal energy circulation.

[0085] The distillation column is maintained at a bottom temperature of 46.4℃, a top temperature of 28.7℃, and a top pressure of 4kPa. The initial hydrogen peroxide solution is separated in the distillation column through a segmented packing layer. Water vapor is distilled from the top of the column at a rate of 6000 kg / h and enters the tube side of the first heat exchanger. The refrigerant in the shell side of the first heat exchanger absorbs heat from the water vapor and evaporates at a temperature of approximately 35℃. The water vapor then condenses into liquid water at a temperature ≤10℃. The liquid water enters the cold water tank through the tube side outlet. The reflux rate from the cold water tank to the distillation column is controlled according to the reflux ratio. The remaining portion is stored in the cold water tank, which is maintained at a water temperature ≤10℃ by a vacuum insulation structure.

[0086] The hydrogen peroxide (50% concentration, 46.4℃, bottom flow rate 4000 kg / h) at the bottom of the distillation column enters the tube side of the falling film heat exchanger; the refrigerant at a temperature of about 54℃ after evaporation in the shell side of the first heat exchanger enters the shell side of the falling film heat exchanger, providing a reboiling heat source for the hydrogen peroxide in the tube side; causing some of the hydrogen peroxide in the tube side to evaporate into steam, which returns to the bottom of the distillation column to replenish the rising steam, while the unevaporated hydrogen peroxide is used as a product and is transported to the hydrogen peroxide concentration storage tank through the tube side outlet.

[0087] Unused refrigerant in the shell side of the falling film heat exchanger is cooled in the auxiliary condenser. The refrigerant condensed in the falling film heat exchanger is combined with the refrigerant processed in the auxiliary condenser and returned to the shell side of the first heat exchanger via the circulation pump to complete the cycle. The auxiliary condenser only processes excess refrigerant to ensure that the shell side refrigerant pressure is stable at 0.5 MPa and to avoid system overpressure.

[0088] During the process, the TDLAS sensor, temperature sensor, and pressure sensor at the tube outlet of the falling film heat exchanger collect data in real time, and the signals are connected to an independent SIS system. The safety interlock thresholds are set as follows: dissolved O2 concentration rise rate ≥ 0.1 ppm / s; temperature change rate ≥ 0.5℃ / min; dynamic safety threshold ≥ 68℃; pressure change rate ≥ 0.1 MPa / min; absolute pressure ≥ 0.9 MPa.

[0089] When the SIS system detects any of the above conditions, it immediately triggers the safety interlock. The emergency valve opens within 80ms, and liquid water at ≤10℃ in the cold water tank is injected into the tube side of the falling film heat exchanger. The low-temperature water rapidly exchanges heat with the hydrogen peroxide in the tube side, achieving rapid cooling and dilution. After the safety interlock is triggered, the system executes the emergency shutdown procedure (ESD), including interlocking to stop the feed, cutting off the heat source, depressurizing, and discharging the materials in the system into the emergency pool. The system can only be restarted after a full inspection confirms that everything is in order.

[0090] Example 2 (Hydrogen peroxide concentration at the bottom of the tower: 55%):

[0091] The hydrogen peroxide purification system using the same piping connection as in Example 1 has the following adjusted operating procedure:

[0092] Introduce an initial hydrogen peroxide solution with a concentration of 30% into the distillation column at a feed rate of 10,000 kg / h, and maintain the liquid level at 1.2 m. Check the cold water tank to ensure that it contains liquid water at ≤10℃ left over from the previous batch, and maintain the liquid level at 50%. Close the emergency valve and turn on the auxiliary condenser and refrigerant circulation pump to allow the refrigerant to circulate initially in the shell side of the first heat exchanger.

[0093] Turn on the external steam source for the shell side of the standby heat exchanger, and stabilize the steam pressure at 0.6 MPa. At the same time, slowly open the regulating valve and shut-off valve for the tube side of the standby heat exchanger to allow liquid water from the cold water tank to enter the tube side. After absorbing the heat from the steam, the liquid water is converted into clean steam at a temperature of about 105°C, which is then introduced into the bottom of the distillation column to heat the initial hydrogen peroxide solution. Control the steam flow rate by regulating the regulating valve to raise the temperature at the bottom of the distillation column to 48.3°C at a rate of 1°C / min, gradually raise the temperature at the top of the column to 28.7°C, and stabilize the pressure at the top of the column at 4 kPa.

[0094] The reflux at the top of the distillation column is continuously monitored. When the top temperature stabilizes at 28.7℃ and the top pressure at 4kPa, and a stable reflux (reflux flow rate of 11460kg / h) is observed at the top through the sight glass, the system is considered to have entered a stable state. At this time, the steam source of the shell side of the standby heat exchanger is shut off, the regulating valve and shut-off valve of the tube side are cut off, and the standby heat exchanger is isolated. At the same time, the refrigerant at the shell side outlet of the first heat exchanger is adjusted to enter the shell side of the falling film heat exchanger. The remaining refrigerant processed by the falling film heat exchanger is then processed by the auxiliary condenser, completing the switch from external heating to internal energy circulation.

[0095] The distillation column is maintained at a bottom temperature of 48.3℃, a top temperature of 28.7℃, and a top pressure of 4kPa. The initial hydrogen peroxide solution is separated in the distillation column through a segmented packing layer. Water vapor is distilled from the top of the column, with a top vapor flow rate of 17823 kg / h, and enters the tube side of the first heat exchanger. The refrigerant in the shell side of the first heat exchanger absorbs heat from the water vapor and evaporates at an evaporation temperature of approximately 35℃. The water vapor then condenses into liquid water at a temperature ≤10℃. The liquid water enters the cold water tank through the tube side outlet. The reflux flow rate from the cold water tank to the distillation column is controlled according to the reflux ratio. The remaining portion is stored in the cold water tank, which is maintained at a water temperature ≤10℃ by a vacuum insulation structure.

[0096] The hydrogen peroxide (concentration 55%, temperature 48.3℃, bottom flow rate 3637kg / h) at the bottom of the distillation column enters the tube side of the falling film heat exchanger; the refrigerant at a temperature of about 54℃ after evaporation in the shell side of the first heat exchanger enters the shell side of the falling film heat exchanger, providing a reboiling heat source for the hydrogen peroxide in the tube side; causing some of the hydrogen peroxide in the tube side to evaporate into steam, which returns to the bottom of the distillation column to replenish the rising steam, and the unevaporated hydrogen peroxide, as the product, is transported to the hydrogen peroxide concentration storage tank through the tube side outlet.

[0097] Unused refrigerant in the shell side of the falling film heat exchanger is cooled in the auxiliary condenser. The refrigerant condensed in the falling film heat exchanger is combined with the refrigerant processed in the auxiliary condenser and returned to the shell side of the first heat exchanger via the circulation pump to complete the cycle. The auxiliary condenser only processes excess refrigerant to ensure that the shell side refrigerant pressure is stable at 0.5 MPa and to avoid system overpressure.

[0098] During the process, the TDLAS sensor, temperature sensor, and pressure sensor at the tube outlet of the falling film heat exchanger collect data in real time, and the signals are connected to an independent SIS system. The safety interlock thresholds are set as follows: dissolved O2 concentration rise rate ≥ 0.1 ppm / s; temperature change rate ≥ 0.5℃ / min; dynamic safety threshold ≥ 66℃; pressure change rate ≥ 0.1 MPa / min; absolute pressure ≥ 0.9 MPa.

[0099] When the SIS system detects any of the above conditions, it immediately triggers the safety interlock. The emergency valve opens within 80ms, and liquid water at ≤10℃ in the cold water tank is injected into the tube side of the falling film heat exchanger. The low-temperature water rapidly exchanges heat with the hydrogen peroxide in the tube side, achieving rapid cooling and dilution. After the safety interlock is triggered, the system executes the emergency shutdown procedure (ESD), including interlocking to stop the feed, cutting off the heat source, depressurizing, and discharging the materials in the system into the emergency pool. The system can only be restarted after a full inspection confirms that everything is in order.

[0100] Example 3 (Hydrogen peroxide concentration at the bottom of the tower: 60%):

[0101] The hydrogen peroxide purification system using the same piping connection as in Example 1 has the following adjusted operating procedure:

[0102] Introduce an initial hydrogen peroxide solution with a concentration of 30% into the distillation column at a feed rate of 10,000 kg / h, and maintain the liquid level at 1.2 m. Check the cold water tank to ensure that it contains liquid water at ≤10℃ left over from the previous batch, and maintain the liquid level at 50%. Close the emergency valve and turn on the auxiliary condenser and refrigerant circulation pump to allow the refrigerant to circulate initially in the shell side of the first heat exchanger.

[0103] Turn on the external steam source for the shell side of the standby heat exchanger, and stabilize the steam pressure at 0.6 MPa. At the same time, slowly open the regulating valve and shut-off valve for the tube side of the standby heat exchanger to allow liquid water from the cold water tank to enter the tube side. After absorbing the heat from the steam, the liquid water is converted into clean steam at a temperature of about 105°C, which is then introduced into the bottom of the distillation column to heat the initial hydrogen peroxide solution. Control the steam flow rate through the regulating valve to raise the temperature at the bottom of the distillation column to 50.9°C at a rate of 1°C / min, gradually raise the temperature at the top of the column to 28.7°C, and stabilize the pressure at the top of the column at 4 kPa.

[0104] The reflux at the top of the distillation column is continuously monitored. When the top temperature stabilizes at 28.7℃ and the top pressure at 4kPa, and a stable reflux (reflux flow rate of 12008kg / h) is observed at the top through the sight glass, the system is considered to have entered a stable state. At this time, the steam source of the shell side of the standby heat exchanger is shut off, the regulating valve and shut-off valve of the tube side are cut off, and the standby heat exchanger is isolated. At the same time, the refrigerant at the shell side outlet of the first heat exchanger is adjusted to enter the shell side of the falling film heat exchanger. The remaining refrigerant processed by the falling film heat exchanger is then processed by the auxiliary condenser, completing the switch from external heating to internal energy circulation.

[0105] The distillation column is maintained at a bottom temperature of 50.9℃, a top temperature of 28.7℃, and a top pressure of 4kPa. The initial hydrogen peroxide solution is separated in the distillation column through a segmented packing layer. Water vapor is distilled from the top of the column, with a top vapor flow rate of 16667 kg / h, and enters the tube side of the first heat exchanger. The refrigerant in the shell side of the first heat exchanger absorbs heat from the water vapor and evaporates at an evaporation temperature of approximately 35℃. The water vapor then condenses into liquid water at a temperature ≤10℃. The liquid water enters the cold water tank through the tube side outlet. The reflux flow rate from the cold water tank to the distillation column is controlled according to the reflux ratio. The remaining portion is stored in the cold water tank, which is maintained at a water temperature ≤10℃ by a vacuum insulation structure.

[0106] The hydrogen peroxide (60% concentration, 50.9℃, bottom flow rate 3333kg / h) at the bottom of the distillation column enters the tube side of the falling film heat exchanger; the refrigerant at a temperature of about 56℃ after evaporation in the shell side of the first heat exchanger enters the shell side of the falling film heat exchanger, providing a reboiling heat source for the hydrogen peroxide in the tube side; causing some of the hydrogen peroxide in the tube side to evaporate into steam, which returns to the bottom of the distillation column to replenish the rising steam, and the unevaporated hydrogen peroxide, as the product, is transported to the hydrogen peroxide concentration storage tank through the tube side outlet.

[0107] Unused refrigerant in the shell side of the falling film heat exchanger is cooled in the auxiliary condenser. The refrigerant condensed in the falling film heat exchanger is combined with the refrigerant processed in the auxiliary condenser and returned to the shell side of the first heat exchanger via the circulation pump to complete the cycle. The auxiliary condenser only processes excess refrigerant to ensure that the shell side refrigerant pressure is stable at 0.5 MPa and to avoid system overpressure.

[0108] During the process, the TDLAS sensor, temperature sensor, and pressure sensor at the tube outlet of the falling film heat exchanger collect data in real time, and the signals are connected to an independent SIS system. The safety interlock thresholds are set as follows: dissolved O2 concentration rise rate ≥ 0.1 ppm / s; temperature change rate ≥ 0.5℃ / min; dynamic safety threshold ≥ 64℃; pressure change rate ≥ 0.1 MPa / min; absolute pressure ≥ 0.9 MPa.

[0109] When the SIS system detects any of the above conditions, it immediately triggers the safety interlock. The emergency valve opens within 80ms, and liquid water at ≤10℃ in the cold water tank is injected into the tube side of the falling film heat exchanger. The low-temperature water rapidly exchanges heat with the hydrogen peroxide in the tube side, achieving rapid cooling and dilution. After the safety interlock is triggered, the system executes the emergency shutdown procedure (ESD), including interlocking to stop the feed, cutting off the heat source, depressurizing, and discharging the materials in the system into the emergency pool. The system can only be restarted after a full inspection confirms that everything is in order.

[0110] Example 4 (Hydrogen peroxide concentration at the bottom of the tower: 65%):

[0111] The hydrogen peroxide purification system using the same piping connection as in Example 1 has the following adjusted operating procedure:

[0112] Introduce an initial hydrogen peroxide solution with a concentration of 30% into the distillation column at a feed rate of 10,000 kg / h, and maintain the liquid level at 1.2 m. Check the cold water tank to ensure that it contains liquid water at ≤10℃ left over from the previous batch, and maintain the liquid level at 50%. Close the emergency valve and turn on the auxiliary condenser and refrigerant circulation pump to allow the refrigerant to circulate initially in the shell side of the first heat exchanger.

[0113] Turn on the external steam source for the shell side of the standby heat exchanger, and stabilize the steam pressure at 0.6 MPa. At the same time, slowly open the regulating valve and shut-off valve for the tube side of the standby heat exchanger to allow liquid water from the cold water tank to enter the tube side. After absorbing the heat from the steam, the liquid water is converted into clean steam at a temperature of about 105°C, which is then introduced into the bottom of the distillation column to heat the initial hydrogen peroxide solution. By controlling the steam flow rate through the regulating valve, the temperature at the bottom of the distillation column rises to 53.1°C at a rate of 1°C / min, the temperature at the top of the column gradually rises to 28.7°C, and the pressure at the top of the column stabilizes at 4 kPa.

[0114] The reflux at the top of the distillation column is continuously monitored. When the top temperature stabilizes at 28.7℃ and the top pressure at 4kPa, and a stable reflux (reflux flow rate of 12469kg / h) is observed at the top through the sight glass, the system is considered to have entered a stable state. At this time, the steam source of the shell side of the standby heat exchanger is shut off, the regulating valve and shut-off valve of the tube side are cut off, and the standby heat exchanger is isolated. At the same time, the refrigerant at the shell side outlet of the first heat exchanger is adjusted to enter the shell side of the falling film heat exchanger. The remaining refrigerant processed by the falling film heat exchanger is then processed by the auxiliary condenser, completing the switch from external heating to internal energy circulation.

[0115] The distillation column is maintained at a bottom temperature of 53.1℃, a top temperature of 28.7℃, and a top pressure of 4kPa. The initial hydrogen peroxide solution is separated in the distillation column through a segmented packing layer. Water vapor is distilled from the top of the column, with a top vapor flow rate of 6923 kg / h, and enters the tube side of the first heat exchanger. The refrigerant in the shell side of the first heat exchanger absorbs heat from the water vapor and evaporates at an evaporation temperature of approximately 35℃. The water vapor then condenses into liquid water at a temperature ≤10℃. The liquid water enters the cold water tank through the tube side outlet. The reflux flow rate from the cold water tank to the distillation column is controlled according to the reflux ratio. The remaining portion is stored in the cold water tank, which is maintained at a water temperature ≤10℃ by a vacuum insulation structure.

[0116] The hydrogen peroxide (65% concentration, 53.1℃ temperature, bottom flow rate 3077 kg / h) at the bottom of the distillation column enters the tube side of the falling film heat exchanger; the refrigerant at a temperature of about 56℃ after evaporation in the shell side of the first heat exchanger enters the shell side of the falling film heat exchanger, providing a reboiling heat source for the hydrogen peroxide in the tube side; causing some of the hydrogen peroxide in the tube side to evaporate into steam, which returns to the bottom of the distillation column to replenish the rising steam, and the unevaporated hydrogen peroxide, as the product, is transported to the hydrogen peroxide concentration storage tank through the tube side outlet.

[0117] Unused refrigerant in the shell side of the falling film heat exchanger is cooled in the auxiliary condenser. The refrigerant condensed in the falling film heat exchanger is combined with the refrigerant processed in the auxiliary condenser and returned to the shell side of the first heat exchanger via the circulation pump to complete the cycle. The auxiliary condenser only processes excess refrigerant to ensure that the shell side refrigerant pressure is stable at 0.5 MPa and to avoid system overpressure.

[0118] During the process, the TDLAS sensor, temperature sensor, and pressure sensor at the tube outlet of the falling film heat exchanger collect data in real time, and the signals are connected to an independent SIS system. The safety interlock thresholds are set as follows: dissolved O2 concentration rise rate ≥ 0.1 ppm / s; temperature change rate ≥ 0.5℃ / min; dynamic safety threshold ≥ 62℃; pressure change rate ≥ 0.1 MPa / min; absolute pressure ≥ 0.9 MPa.

[0119] When the SIS system detects any of the above conditions, it immediately triggers the safety interlock. The emergency valve opens within 80ms, and liquid water at ≤10℃ in the cold water tank is injected into the tube side of the falling film heat exchanger. The low-temperature water rapidly exchanges heat with the hydrogen peroxide in the tube side, achieving rapid cooling and dilution. After the safety interlock is triggered, the system executes the emergency shutdown procedure (ESD), including interlocking to stop the feed, cutting off the heat source, depressurizing, and discharging the materials in the system into the emergency pool. The system can only be restarted after a full inspection confirms that everything is in order.

[0120] Example 5 (70% hydrogen peroxide concentration at the bottom of the tower):

[0121] The hydrogen peroxide purification system using the same piping connection as in Example 1 has the following adjusted operating procedure:

[0122] Introduce an initial hydrogen peroxide solution with a concentration of 30% into the distillation column at a feed rate of 10,000 kg / h, and maintain the liquid level at 1.2 m. Check the cold water tank to ensure that it contains liquid water at ≤10℃ left over from the previous batch, and maintain the liquid level at 50%. Close the emergency valve and turn on the auxiliary condenser and refrigerant circulation pump to allow the refrigerant to circulate initially in the shell side of the first heat exchanger.

[0123] Turn on the external steam source for the shell side of the standby heat exchanger, and stabilize the steam pressure at 0.6 MPa. At the same time, slowly open the regulating valve and shut-off valve for the tube side of the standby heat exchanger to allow liquid water from the cold water tank to enter the tube side. After absorbing the heat from the steam, the liquid water is converted into clean steam at a temperature of about 105°C, which is then introduced into the bottom of the distillation column to heat the initial hydrogen peroxide solution. By controlling the steam flow rate through the regulating valve, the temperature at the bottom of the distillation column rises to 56.2°C at a rate of 1°C / min, the temperature at the top of the column gradually rises to 28.7°C, and the pressure at the top of the column stabilizes at 4 kPa.

[0124] The reflux at the top of the distillation column is continuously monitored. When the top temperature stabilizes at 28.7℃ and the top pressure at 4kPa, and a stable reflux (reflux liquid flow rate of 12865kg / h) is observed at the top through the sight glass, the system is considered to have entered a stable state. At this time, the steam source of the shell side of the standby heat exchanger is shut off, the regulating valve and shut-off valve of the tube side are cut off, and the standby heat exchanger is isolated. At the same time, the refrigerant at the shell side outlet of the first heat exchanger is adjusted to enter the shell side of the falling film heat exchanger. The remaining refrigerant processed by the falling film heat exchanger is then processed by the auxiliary condenser, completing the switch from external heating to internal energy circulation.

[0125] The distillation column is maintained at a bottom temperature of 56.2℃, a top temperature of 28.7℃, and a top pressure of 4kPa. The initial hydrogen peroxide solution is separated in the distillation column through a segmented packing layer. Water vapor is distilled from the top of the column, with a top vapor flow rate of 7143 kg / h, and enters the tube side of the first heat exchanger. The refrigerant in the shell side of the first heat exchanger absorbs heat from the water vapor and evaporates at an evaporation temperature of approximately 35℃. The water vapor then condenses into liquid water at a temperature ≤10℃. The liquid water enters the cold water tank through the tube side outlet. The reflux flow rate from the cold water tank to the distillation column is controlled according to the reflux ratio. The remaining portion is stored in the cold water tank, which is maintained at a water temperature ≤10℃ by a vacuum insulation structure.

[0126] The hydrogen peroxide (70% concentration, 56.2℃, bottom flow rate 2857 kg / h) at the bottom of the distillation column enters the tube side of the falling film heat exchanger; the refrigerant at a temperature of about 58℃ after evaporation in the shell side of the first heat exchanger enters the shell side of the falling film heat exchanger, providing a reboiling heat source for the hydrogen peroxide in the tube side; causing some of the hydrogen peroxide in the tube side to evaporate into steam, which returns to the bottom of the distillation column to replenish the rising steam, while the unevaporated hydrogen peroxide is used as a product and is transported to the hydrogen peroxide concentration storage tank through the tube side outlet.

[0127] Unused refrigerant in the shell side of the falling film heat exchanger is cooled in the auxiliary condenser. The refrigerant condensed in the falling film heat exchanger is combined with the refrigerant processed in the auxiliary condenser and returned to the shell side of the first heat exchanger via the circulation pump to complete the cycle. The auxiliary condenser only processes excess refrigerant to ensure that the shell side refrigerant pressure is stable at 0.5 MPa and to avoid system overpressure.

[0128] During the process, the TDLAS sensor, temperature sensor, and pressure sensor at the tube outlet of the falling film heat exchanger collect data in real time, and the signals are connected to an independent SIS system. The safety interlock thresholds are set as follows: dissolved O2 concentration rise rate ≥ 0.1 ppm / s; temperature change rate ≥ 0.5℃ / min; dynamic safety threshold ≥ 60℃; pressure change rate ≥ 0.1 MPa / min; absolute pressure ≥ 0.9 MPa.

[0129] When the SIS system detects any of the above conditions, it immediately triggers the safety interlock. The emergency valve opens within 80ms, and liquid water at ≤10℃ in the cold water tank is injected into the tube side of the falling film heat exchanger. The low-temperature water rapidly exchanges heat with the hydrogen peroxide in the tube side, achieving rapid cooling and dilution. After the safety interlock is triggered, the system executes the emergency shutdown procedure (ESD), including interlocking to stop the feed, cutting off the heat source, depressurizing, and discharging the materials in the system into the emergency pool. The system can only be restarted after a full inspection confirms that everything is in order.

[0130] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for purifying hydrogen peroxide, characterized in that, Includes the following steps: S1 introduces an initial hydrogen peroxide solution with a concentration of 20-35% into the distillation column; S2 sends the water vapor distilled from the top of the distillation column into the tube side of the first heat exchanger to be condensed, and the resulting liquid water is fed into the cold water tank and partially returned to the distillation column; The refrigerant in the shell side of the first heat exchanger of S3 absorbs heat and evaporates before entering the shell side of the falling film heat exchanger. It provides a reboiling heat source for the purified hydrogen peroxide with a concentration of 50-70% that is output from the bottom of the distillation column to the tube side of the falling film heat exchanger, so that part of it evaporates and returns to the distillation column to provide rising steam, while the unevaporated part is output as product. S4 When the system triggers the safety interlock condition, the emergency valve set between the cold water tank and the tube side of the falling film heat exchanger is opened to achieve rapid cooling and dilution; The safety interlock condition is as follows: the emergency valve will be opened immediately when any of the following conditions are met: a. The rate of increase in dissolved O2 concentration is ≥0.1 ppm / s; b. Temperature change rate ≥ 0.5℃ / min; c. Actual temperature ≥ dynamic safety threshold; d. Pressure change rate ≥ 0.1 MPa / min; e. Absolute pressure ≥ safe pressure limit; The dynamic safety threshold is set as the theoretical self-accelerating decomposition temperature at the current concentration minus 10-15℃; the safety pressure limit is 90% of the design pressure of the falling film heat exchanger.

2. The method for purifying hydrogen peroxide according to claim 1, characterized in that, In step S1, the separation temperature in the distillation column is 50-68℃. During the initial startup, the standby heat exchanger uses the heat of external steam to convert the liquid water in its tube side into clean steam, which is used to heat the initial hydrogen peroxide solution in the distillation column. The liquid water in the tube side of the standby heat exchanger is the liquid water in the previous batch of cold water tank.

3. The method for purifying hydrogen peroxide according to claim 1, characterized in that, In step S2, the temperature of the water vapor distilled from the top of the distillation column is 26-30℃; the water vapor is condensed into liquid water at ≤10℃, and the cold water tank adopts a double-layer vacuum insulation structure.

4. The hydrogen peroxide purification method according to claim 1, characterized in that, In step S3, after the refrigerant absorbs heat and evaporates, it all enters the shell side of the falling film heat exchanger. The excess refrigerant that is not completely condensed in the shell side of the falling film heat exchanger enters the auxiliary condenser and is completely condensed before returning to the first heat exchanger for recycling. The temperature difference between the shell side and the tube side of the falling film heat exchanger is 3-15℃, the temperature of the hydrogen peroxide output from the bottom of the distillation column is 50-68℃, and the temperature of the refrigerant entering the shell side of the falling film heat exchanger is 55-80℃.

5. The method for purifying hydrogen peroxide according to claim 1, characterized in that, The refrigerant is a Freon-based refrigerant or a hydrocarbon refrigerant.

6. The method for purifying hydrogen peroxide according to claim 1, characterized in that, In step S4, after the emergency valve is opened, the chiller that supplies refrigerant to the shell side of the first heat exchanger is shut off, and the passage for liquid water in the cold water tank to flow back to the distillation column is maintained.

7. A hydrogen peroxide purification system according to any one of claims 1 to 6, characterized in that, include: Distillation column, first heat exchanger, cold water tank, falling film heat exchanger, standby heat exchanger and auxiliary condenser; The top outlet of the distillation column is connected to the tube-side inlet of the first heat exchanger, and the tube-side outlet of the first heat exchanger is connected to a cold water tank. The cold water tank is provided with two outlets, which are respectively connected to the top reflux port of the distillation column and the tube-side inlet of the falling film heat exchanger. An emergency valve is provided between the cold water tank and the tube-side of the falling film heat exchanger. The bottom outlet of the distillation column is connected to the tube-side inlet of the falling film heat exchanger; the tube-side outlet of the falling film heat exchanger is connected to the hydrogen peroxide concentration storage tank; and the tube-side vapor outlet of the falling film heat exchanger is connected to the reflux port at the bottom of the distillation column. The shell-side outlet of the first heat exchanger is connected to the shell-side inlet of the falling film heat exchanger, the shell-side outlet of the falling film heat exchanger is connected to the feed inlet of the auxiliary condenser and the shell-side inlet of the first heat exchanger, and the discharge outlet of the auxiliary condenser is connected to the shell-side inlet of the first heat exchanger. The tube-side inlet of the standby heat exchanger is connected to a cold water tank and is equipped with a regulating valve and a shut-off valve; the tube-side outlet is connected to the bottom of the distillation column; the shell-side inlet is connected to an external steam source; and the shell-side outlet is connected to a condensate recovery system.

8. A hydrogen peroxide purification system according to claim 7, characterized in that, The tube outlet of the falling film heat exchanger is equipped with a TDLAS sensor, a temperature sensor, and a pressure sensor to monitor the rate of increase of dissolved O2 concentration and the system temperature / pressure changes in real time. All sensor signals are connected to an independent safety instrument system, and the action delay of triggering the emergency valve is <100ms.

9. A hydrogen peroxide purification system according to claim 7, characterized in that, The backup heat exchanger is only used during the system startup phase; when the temperature at the bottom of the distillation column reaches 50-68℃ and a stable reflux is established at the top of the column, the heat source is switched to the falling film heat exchanger, and the backup heat exchanger is isolated.

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