Working solution flash dehydration system and method in process of preparing hydrogen peroxide by anthraquinone process

Abstract

The invention discloses a working solution flash dehydration system and method in hydrogen peroxide preparation through an anthraquinone method in the field of hydrogen peroxide production, and the method comprises the following steps: waste heat recovery and preheating: waste heat of an oxidation process outlet solution in hydrogen peroxide preparation through the anthraquinone method is used for heat exchange; carrying out super-gravity preliminary dehydration, and removing non-dissolved water by using a rotating packed bed filled with nickel-based foam metal filler; carrying out flash evaporation for deep dehydration, doping pressure response type carrier gas microspheres, and then carrying out flash evaporation; gas-liquid separation and product collection are carried out, liquid drops are removed through a spiral fluid director, and dehydration is completed. According to the invention, a supergravity and flash coupling technology is adopted, so that the overall dehydration effect is prominent; the occupied area of equipment is reduced, and the technological process is simplified; according to the process, waste heat of the outlet liquid in the oxidation process in the anthraquinone process for preparing hydrogen peroxide is utilized for preheating, and energy consumption can be effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen peroxide production, and in particular to a flash evaporation and dehydration system and method for a working liquid in hydrogen peroxide production using an anthraquinone process. Background Art

[0002] The anthraquinone method is currently the mainstream process for producing hydrogen peroxide (H2O2) in industry. The main steps include: ① Preparation of the working solution: 2-ethylanthraquinone (EAQ) or tetrahydro-2-ethylanthraquinone is added to heavy aromatic hydrocarbons and trioctyl phosphate as solvents, heated and dissolved to form a working solution, which is then washed and purified for later use. ② Hydrogenation: The working solution reacts with hydrogen over a palladium catalyst, converting EAQ into 2-ethylhydroanthraquinone (H2AQ). ③ Oxidation: The hydrogenated solution reacts with compressed air in an oxidation tower, oxidizing H2AQ to regenerate EAQ and generate hydrogen peroxide. ④ Extraction and purification: The oxidation solution is countercurrently exposed to pure water in a sieve plate extraction tower, extracting hydrogen peroxide to form crude H2O2 (27.5%). The crude product is then purified by a heavy aromatics purification tower to remove organic impurities, yielding a qualified rare product. ⑤ Concentration: A portion of the rare product is concentrated under reduced pressure in a rising film evaporator to obtain a high-concentration product, such as 50%. The condensed water is then reused in the extraction process. ⑥ Working fluid post-treatment: The raffinate (working fluid containing EAQ) is dehydrated in the alkali tower and regenerated in the clay bed, and then returned to the hydrogenation process for recycling.

[0003] As can be seen, the working fluid is the "circulating carrier" of the anthraquinone process, acting as a hydrogen transfer medium, a phase transfer platform, and a reaction medium. The working fluid's performance determines production efficiency, EAQ concentration, and solvent ratio, while its water content directly impacts catalytic activity, yield, and equipment life. Therefore, the working fluid must be deeply dehydrated before returning to the hydrogenation process. This protects the palladium catalyst, prevents phase separation, and prevents equipment corrosion, while also maintaining the effectiveness of the clay bed.

[0004] As mentioned above, traditional dehydration of the working fluid in anthraquinone-based hydrogen peroxide production primarily relies on alkaline tower dehydration. However, this process can easily lead to significant alkalinity in the working fluid exiting the drying tower. Once this alkaline material enters the oxidation and extraction systems, it can cause the hydrogen peroxide to violently decompose, potentially posing an explosion hazard. In recent years, vacuum flash dehydration has emerged as a post-treatment method for the working fluid. Due to its deep dehydration capabilities and environmental advantages, it is gradually replacing alkaline tower dehydration. For example, Chinese patent publication number CN108264024B discloses a combined method and apparatus for deep dehydration of the working fluid in anthraquinone-based hydrogen peroxide production. This method combines reduced-pressure flash evaporation with other processes, offering strong economic and applicability. In theory, vacuum dehydration can achieve a 100% dehydration rate (although this is generally not sought, as energy consumption increases significantly with increasing dehydration rates).

[0005] However, the existing vacuum flash dehydration still has the following defects: (1) The process is lengthy: for example, in the above-mentioned CN108264024B process, the actual dehydration process alone requires a series of five stages of equipment: cyclone → coarse granulation → fiber bed → corrugated plate → flash tank; (2) Low thermal energy utilization: It relies on external "circulating liquid heating" and does not utilize the waste heat of the working fluid itself (the liquid temperature at the outlet of the oxidation process is 70-80°C). The additional energy consumption accounts for about 45% of the total energy consumption of the dehydration unit. Summary of the Invention

[0006] The object of the present invention is to provide a system and method for flash dehydration of a working solution in hydrogen peroxide produced by anthraquinone process, which solves the defects of the existing vacuum flash dehydration process, such as a lengthy process and low thermal energy utilization rate.

[0007] The present invention achieves the above-mentioned purpose through the following technical solutions: A method for flash dehydration of a working solution in the production of hydrogen peroxide by anthraquinone, comprising the following steps: S1, waste heat recovery preheating The working fluid to be dehydrated is pumped into a spiral plate heat exchanger, and the waste heat of the outlet liquid of the oxidation process in the anthraquinone process for hydrogen peroxide production is used for heat exchange, so that the working fluid is preheated to 70±2℃; S2. Initial dehydration under high gravity A rotating packed bed filled with nickel-based metal foam filler was constructed. The preheated working fluid was sprayed into the rotor cavity from the central axial feed port of the rotating packed bed. The rotor speed was controlled at 3000-3200 rpm, so that the working fluid was radially ejected from the filler and discharged from the packed bed outlet. Undissolved water was captured and collected by the hydrophilic surface of the filler. S3, flash deep dehydration Pressure-responsive carrier gas microspheres are added at a dosage of 10-15 g / L to the working fluid discharged from the packed bed at a temperature of 60±2°C. The working fluid is then introduced into a flash tank, and the absolute pressure of the flash tank is controlled at 10-12 kPa to cause flash evaporation of dissolved water in the working fluid. Simultaneously, the pressure-responsive carrier gas microspheres are broken by the internal and external pressure differential, causing the internal carrier gas to expand and diffuse, generating an impact airflow to promote the flash evaporation process, and forming a gas-liquid mixture after flash evaporation. S4. Gas-liquid separation and product collection The gas-liquid mixture after flash evaporation is introduced into the spiral guide, where droplets are removed under the action of cyclone, and the dehydrated working liquid is obtained by converging, while the steam and carrier gas are discharged from the top of the spiral guide to complete the dehydration.

[0008] A further improvement is that in step S1, the flow rate of the working fluid in the spiral plate heat exchanger is 25-35m 3 / h, the pressure is 0.5-0.8MPa, the flow rate of the oxidation process outlet liquid in the spiral plate heat exchanger is 30-40m 3 / h, pressure is 1-1.2MPa.

[0009] A further improvement is that in step S2, the porosity of the nickel-based foam metal filler is 93-96%, and the filler is made of nickel foam with a hydroxyapatite coating electrochemically deposited on the surface, and the water contact angle θ on the filler surface is less than 25°; The preparation method of the nickel-based foam metal filler is as follows: pre-treating the nickel foam, dissolving calcium nitrate, ammonium dihydrogen phosphate, disodium ethylenediaminetetraacetic acid, sodium chloride and triethanolamine in deionized water, adjusting the pH to 9.5±0.1, stirring at 38-42°C for 1.5-2.5 hours to obtain an electrochemical deposition solution, performing electrochemical deposition with a platinum sheet as an anode and the nickel foam as a cathode to deposit a hydroxyapatite coating on the surface of the nickel foam, immersing the nickel foam in deionized water at 75-85°C for 10-15 hours, taking it out and performing a vacuum heat treatment at 280-300°C for 0.8-1.2 hours, and finally cleaning the surface to obtain the nickel-based foam metal filler.

[0010] A further improvement is that the pretreatment refers to: immersing the nickel foam in acetone and using ultrasonic cleaning with a frequency of 35-45kHz and a power of 280-300W for 25-30 minutes to remove grease, blowing it out with nitrogen to dry it, and then immersing it in a NaOH solution with a temperature of 55-65°C and a concentration of 8-12wt% for 12-15 minutes to remove the oxide film, rinsing it with deionized water after taking it out, and then immersing it in a room temperature H2SO4-HNO3 mixed acid with a volume ratio of 3:1 for 100-120 seconds for surface etching, and then immediately transferring it to deionized water to terminate the reaction.

[0011] A further improvement is that the concentrations of the components in the electrochemical deposition solution are: calcium nitrate 0.16-0.18 mol / L, ammonium dihydrogen phosphate 0.08-0.12 mol / L, disodium ethylenediaminetetraacetic acid 0.04-0.06 mol / L, sodium chloride 0.12-0.15 mol / L and triethanolamine 4-6 mL / L.

[0012] A further improvement is that the current density of the electrochemical deposition is 2.5 mA / cm², the temperature is 65±1°C, the time is 130-150 min, and the thickness of the obtained hydroxyapatite coating is 10±1 μm.

[0013] A further improvement is that in step S3, the density of the pressure-responsive gas-carrying microspheres is 0.9-0.91 g / cm 3 , carrier gas pressure is 120-130kPa; The preparation method of the pressure-responsive gas-carrier microspheres is as follows: porous hollow polylactic acid microspheres are prepared by a template method, the porous hollow polylactic acid microspheres are placed in a vacuum chamber and maintained for 25-30 minutes to remove residual gas, nitrogen is then filled into the chamber to 120-130 kPa and the pressure is maintained for 5-6 hours to allow the nitrogen to diffuse into the micropores, and then an encapsulation liquid is added to the chamber while maintaining the pressure constant, so that the porous hollow polylactic acid microspheres are immersed in the encapsulation liquid, the encapsulation liquid is then discharged, and the chamber is heated to 52-55° C. to dry the porous hollow polylactic acid microspheres and form an encapsulation layer on the surface, thereby obtaining pressure-responsive gas-carrier microspheres; The porous hollow polylactic acid microspheres have a diameter of 9±0.4 μm, a wall thickness of 1.5±0.2 μm, and an encapsulation layer thickness of 0.4±0.1 μm.

[0014] A further improvement is that the specific steps for preparing the porous hollow polylactic acid microspheres are: dissolving polylactic acid in acetonitrile at a ratio of 100 mg:18-22 mL to obtain a coating solution, then taking 10-12% of calcium carbonate by mass of the polylactic acid and dispersing it in the coating solution, and stirring at 48-52°C for 25-35 minutes, followed by centrifugal washing with acetonitrile to obtain polylactic acid microspheres, and then dispersing the polylactic acid microspheres in a 0.18-0.25 mol / L disodium ethylenediaminetetraacetic acid solution and vortexing and oscillating at a speed of 800-1200 r / min for 8-12 hours to remove the calcium carbonate template to obtain porous hollow polylactic acid microspheres.

[0015] A further improvement is that the encapsulation liquid has a viscosity of 250-350 cP and is made of an aqueous solution with a mass concentration of 2-5% polyvinyl alcohol and 5-10% glycerol.

[0016] The present invention also provides a dehydration system for implementing the flash dehydration method of the working solution in the anthraquinone process for producing hydrogen peroxide, the dehydration system comprising: The spiral plate heat exchanger module is used to pump the working fluid to be dehydrated into the spiral plate heat exchanger, and utilize the waste heat of the outlet liquid of the oxidation process in the anthraquinone process to preheat the working fluid to 70±2℃; The rotating packed bed module is used to fill nickel-based foam metal fillers. The preheated working fluid is sprayed into the rotor cavity from the central axial feed port of the rotating packed bed. The rotor speed is controlled at 3000-3200 rpm, so that the working fluid is radially ejected from the filler and discharged from the packed bed outlet. The non-dissolved water is captured and collected by the hydrophilic surface of the filler. The flash tank module is used to add pressure-responsive carrier gas microspheres at a dosage of 10-15 g / L into the working fluid discharged from the packed bed outlet at a temperature of 60±2°C. The working fluid is then introduced into the flash tank, and the absolute pressure of the flash tank is controlled at 10-12 kPa to cause the dissolved water in the working fluid to flash evaporate. Simultaneously, the pressure-responsive carrier gas microspheres are broken by the internal and external pressure differential, causing the internal carrier gas to expand and diffuse to generate an impact airflow to promote the flash evaporation process, and form a gas-liquid mixture after flash evaporation. The spiral deflector module is used to introduce the gas-liquid mixture after flash evaporation into the spiral deflector, remove droplets under the action of swirl, and converge to obtain the dehydrated working liquid, while the steam and carrier gas are discharged from the top of the spiral deflector to complete the dehydration.

[0017] The beneficial effects of the present invention are: (1) The present invention adopts the coupling technology of supergravity and flash evaporation, wherein the supergravity initial dehydration can enhance the separation of non-dissolved water, and the flash evaporation can efficiently remove dissolved water, making the overall dehydration effect outstanding; and the rotating packed bed used integrates the functions of swirl / coarsening / fiber bed, and a single device can complete the initial dehydration, which helps to reduce the equipment footprint and simplify the process flow. At the same time, the design of nickel-based foam metal filler can also resist crystallization adhesion and avoid the problem of fiber bed clogging; (2) The process of the present invention utilizes the waste heat of the outlet liquid of the oxidation process in the anthraquinone method for hydrogen peroxide production to preheat the liquid, which can effectively reduce energy consumption; (3) The present invention mixes pressure-responsive carrier gas microspheres into the working fluid during flash deep dehydration. The microspheres have a density comparable to that of the working fluid and are filled with gas at a pressure slightly greater than normal pressure. They can be evenly suspended and distributed in the working fluid and stably transported under pumping pressure. After entering the flash tank, they are instantly broken by the internal and external pressure difference, causing the internal gas to diffuse and impact the surrounding working fluid, destroying the gas-liquid interface and enhancing mass transfer, thereby accelerating the evaporation and removal of water.

[0018] In addition, the pressure-responsive gas-carrying microspheres will not pollute the working fluid during transportation and after crushing, and are easy to filter and separate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a SEM image of the process of preparing pressure-responsive gas-carrying microspheres in Example 2 of the present invention; Figure 2 Schematic diagram of the dehydration system of the present invention. DETAILED DESCRIPTION

[0020] The present application is described in further detail below in conjunction with the accompanying drawings. It is necessary to point out that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technicians in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0021] 1. Main raw materials The working liquid to be dehydrated is the raffinate from the extraction tower. The solvent is heavy aromatics + trioctyl phosphate, with a volume ratio of 75:25. The anthraquinone carrier is 2-ethylanthraquinone (EAQ). The concentration is about 120 g / L, the temperature is about 40 ° C, the water content is about 4230 ppm, and the initial density is measured to be 0.911 g / cm 3 , its density will decrease slightly with dehydration.

[0022] The outlet liquid of the oxidation process in the anthraquinone method of producing hydrogen peroxide comes from the process of generating H2O2 by oxidation of hydroanthraquinone in the oxidation tower, contains about 2.2g / L of H2O2, and has a temperature of about 75℃.

[0023] Unless otherwise specified, other materials involved in the test are common commercial products.

[0024] 2. Implementation of the Experiment Example 1 A method for flash dehydration of a working solution in the production of hydrogen peroxide by anthraquinone, comprising the following steps: S1, waste heat recovery preheating The working fluid to be dehydrated is pumped into the spiral plate heat exchanger, and the waste heat of the outlet liquid of the oxidation process in the anthraquinone method of hydrogen peroxide is used for heat exchange to preheat the working fluid to 68.1°C. The flow rate of the working fluid in the spiral plate heat exchanger is 25m 3 / h, the pressure is 0.5MPa, the flow rate of the oxidation process outlet liquid in the spiral plate heat exchanger is 30m 3 / h, pressure is 1MPa.

[0025] S2. Initial dehydration under high gravity A rotating packed bed filled with nickel-based metal foam filler was constructed. The preheated working fluid was sprayed into the rotor cavity from the central axial feed port of the rotating packed bed. The rotor speed was controlled at 3000 rpm, so that the working fluid was radially ejected from the filler and discharged from the packed bed outlet. Undissolved water was captured and collected by the hydrophilic surface of the filler. Among them, the porosity of the nickel-based foam metal filler is about 93%, and the filler is made of foam nickel with a hydroxyapatite coating electrochemically deposited on the surface. The water contact angle θ of the filler surface is about 24.5°, and the preparation method of the nickel-based foam metal filler is: take the foam nickel, immerse it in acetone, and use ultrasonic cleaning with a frequency of 35kHz and a power of 280W for 30 minutes to remove grease, take it out and blow it with nitrogen to dry, then immerse it in a 55°C and 8wt% NaOH solution for 15 minutes to remove the oxide film, take it out and rinse it with deionized water, and then immerse it in a room temperature H2SO4-HNO3 mixed acid with a volume ratio of 3:1 for 100 seconds for surface etching, and then immediately transfer it to deionized water to terminate the reaction, and then take 0.16mol / L calcium nitrate. L, 0.08 mol / L ammonium dihydrogen phosphate, 0.04 mol / L disodium ethylenediaminetetraacetic acid, 0.12 mol / L sodium chloride and 4 mL / L triethanolamine were mixed and dissolved in deionized water, the pH was adjusted to 9.4, and then stirred at 38°C for 2.5 hours to obtain an electrochemical deposition solution. Subsequently, electrochemical deposition was carried out using a platinum sheet as an anode and nickel foam as a cathode to deposit a hydroxyapatite coating on the surface of the nickel foam. The current density of the electrochemical deposition was 2.5 mA / cm², the temperature was 64°C, and the time was 130 minutes. The thickness of the obtained hydroxyapatite coating was 10±1 μm. The nickel foam was then immersed in 75°C deionized water and kept warm for 15 hours. After being taken out, it was subjected to a vacuum heat treatment at 280°C for 1.2 hours. Finally, the surface was cleaned to obtain a nickel-based foam metal filler.

[0026] S3, flash deep dehydration Pressure-responsive carrier gas microspheres were added at a dosage of 10 g / L to the working fluid discharged from the packed bed at a temperature of 59.6°C. The working fluid was then introduced into a flash tank with an absolute pressure of 10 kPa. This caused the dissolved water in the working fluid to flash evaporate. Simultaneously, the pressure-responsive carrier gas microspheres shattered under the action of the internal and external pressure differential, causing the internal carrier gas to expand and diffuse, generating an impact airflow that promoted the flash evaporation process. After flash evaporation, a gas-liquid mixture was formed. The density of the pressure-responsive gas-carrying microspheres is 0.906 g / cm 3, the carrier gas pressure is 120kPa; and the preparation method of the pressure-responsive carrier gas microspheres is: porous hollow polylactic acid microspheres are prepared by a template method, specifically: polylactic acid is dissolved in acetonitrile at a ratio of 100mg:18mL to obtain a coating liquid, and then calcium carbonate accounting for 10% of the mass of the polylactic acid is dispersed in the coating liquid, and stirred at 48°C for 35min, followed by centrifugal washing with acetonitrile to obtain polylactic acid microspheres, and then the polylactic acid microspheres are dispersed in 0.18mol / L disodium ethylenediaminetetraacetic acid solution, and vortexed at a speed of 800r / min for 12h to remove the calcium carbonate template to obtain porous hollow polylactic acid microspheres; and then the porous hollow polylactic acid microspheres are placed in a vacuum chamber The pressure was maintained for 25 minutes to remove residual gas, and then nitrogen was filled into the cavity to 120 kPa and maintained for 6 hours to allow nitrogen to diffuse into the ball through the micropores. Then, while maintaining the pressure unchanged, encapsulation liquid was added into the cavity. The viscosity of the encapsulation liquid was 250 cP, and it was made of an aqueous solution with a mass concentration of 2% polyvinyl alcohol and 5% glycerol. The porous hollow polylactic acid microspheres were immersed in the encapsulation liquid. The encapsulation liquid was then discharged and the cavity was heated to 52°C to dry the porous hollow polylactic acid microspheres, and an encapsulation layer was formed on the surface, thereby obtaining pressure-responsive carrier gas microspheres. The obtained porous hollow polylactic acid microspheres had a diameter of 9±0.4 μm, a wall thickness of 1.5±0.2 μm, and an encapsulation layer thickness of 0.4±0.1 μm.

[0027] S4. Gas-liquid separation and product collection The gas-liquid mixture after flash evaporation is introduced into a spiral guide with a spiral angle of 30°. The droplets are removed under the action of the swirl and the dehydrated working liquid is obtained by converging. The steam and carrier gas are discharged from the top of the spiral guide to complete the dehydration.

[0028] Example 2 A method for flash dehydration of a working solution in the production of hydrogen peroxide by anthraquinone, comprising the following steps: S1, waste heat recovery preheating The working fluid to be dehydrated is pumped into the spiral plate heat exchanger, and the waste heat of the outlet liquid of the oxidation process in the anthraquinone process for hydrogen peroxide is used for heat exchange to preheat the working fluid to 70.2°C. The flow rate of the working fluid in the spiral plate heat exchanger is 30m 3 / h, the pressure is 0.6MPa, the flow rate of the oxidation process outlet liquid in the spiral plate heat exchanger is 35m 3 / h, pressure is 1.1MPa.

[0029] S2. Initial dehydration under high gravity A rotating packed bed filled with nickel-based metal foam was constructed. Preheated working fluid was sprayed into the rotor cavity from the central axial feed port of the rotating packed bed. The rotor speed was controlled at 3100 rpm, causing the working fluid to be radially ejected from the packing and discharged from the packed bed outlet. Undissolved water was captured and collected by the hydrophilic surface of the packing. Among them, the porosity of the nickel-based foam metal filler is about 95%, and the filler is made of foam nickel with a hydroxyapatite coating electrochemically deposited on the surface, the water contact angle θ of the filler surface is about 23.4°, and the preparation method of the nickel-based foam metal filler is: take the foam nickel, immerse it in acetone, and use ultrasonic cleaning with a frequency of 40kHz and a power of 290W for 28 minutes to remove grease, take it out and blow it with nitrogen to dry, then immerse it in a 60°C and 10wt% NaOH solution for 14 minutes to remove the oxide film, take it out and rinse it with deionized water, and then immerse it in a room temperature H2SO4-HNO3 mixed acid with a volume ratio of 3:1 for 110 seconds for surface etching, and then immediately transfer it to deionized water to terminate the reaction, and then take 0.17 mol / L, 0.1mol / L ammonium dihydrogen phosphate, 0.05mol / L disodium ethylenediaminetetraacetic acid, 0.13mol / L sodium chloride and 5mL / L triethanolamine were mixed and dissolved in deionized water, the pH was adjusted to 9.5, and then stirred at 40℃ for 2h to obtain an electrochemical deposition solution. Then, a platinum sheet was used as an anode and nickel foam was used as a cathode for electrochemical deposition to deposit a hydroxyapatite coating on the surface of the nickel foam. The current density of the electrochemical deposition was 2.5mA / cm², the temperature was 65℃, and the time was 140min. The thickness of the obtained hydroxyapatite coating was 10±1μm. The nickel foam was then immersed in 80℃ deionized water and kept warm for 12h. After being taken out, it was subjected to a vacuum heat treatment at 290℃ for 1h. Finally, the surface was cleaned to obtain a nickel-based foam metal filler.

[0030] S3, flash deep dehydration Pressure-responsive carrier gas microspheres were added at a dosage of 15 g / L to the working fluid discharged from the packed bed at a temperature of 60.4°C. The working fluid was then introduced into a flash tank with an absolute pressure of 11 kPa. This caused the dissolved water in the working fluid to flash evaporate. Simultaneously, the pressure-responsive carrier gas microspheres shattered under the action of the internal and external pressure differential, causing the internal carrier gas to expand and diffuse, generating an impact airflow that promoted the flash evaporation process. After flash evaporation, a gas-liquid mixture was formed. The density of the pressure-responsive gas-carrying microspheres is 0.908 g / cm 3, the carrier gas pressure is 125kPa; and the preparation method of the pressure-responsive carrier gas microspheres is: porous hollow polylactic acid microspheres are prepared by a template method, specifically: polylactic acid is dissolved in acetonitrile at a ratio of 100mg:20mL to obtain a coating liquid, and then calcium carbonate accounting for 11% of the mass of the polylactic acid is dispersed in the coating liquid, and stirred at 50°C for 30min, followed by centrifugal washing with acetonitrile to obtain polylactic acid microspheres, and then the polylactic acid microspheres are dispersed in 0.22mol / L disodium ethylenediaminetetraacetic acid solution, and vortexed at a speed of 1000r / min for 10h to remove the calcium carbonate template to obtain porous hollow polylactic acid microspheres; and then the porous hollow polylactic acid microspheres are placed in a vacuum chamber The pressure was maintained for 28 minutes to remove residual gas, and then nitrogen was filled into the cavity to 125kPa and maintained for 5.5 hours to allow nitrogen to diffuse into the ball through the micropores. Then, while maintaining the pressure unchanged, encapsulation liquid was added to the cavity. The viscosity of the encapsulation liquid was 300cP, and it was made of an aqueous solution with a mass concentration of 3% polyvinyl alcohol and 8% glycerol. The porous hollow polylactic acid microspheres were immersed in the encapsulation liquid. The encapsulation liquid was then discharged and the cavity was heated to 53°C to dry the porous hollow polylactic acid microspheres, and an encapsulation layer was formed on the surface, thereby obtaining pressure-responsive gas-carrying microspheres. The obtained porous hollow polylactic acid microspheres had a diameter of 9±0.3μm, a wall thickness of 1.5±0.2μm, and an encapsulation layer thickness of 0.4±0.1μm.

[0031] During the preparation of the pressure-responsive gas-carrying microspheres, the surface morphologies of the intermediate porous hollow polylactic acid microspheres and the final product were scanned using a FEI Quanta 200 scanning electron microscope. Figure 1 As shown in the figure, A is the surface micromorphology of the intermediate product porous hollow polylactic acid microspheres, which have uniform pores distributed on the surface, which is conducive to gas penetration. B is the surface micromorphology of the final product pressure-responsive gas-carrying microspheres. It can be seen that the encapsulation layer completely blocks the surface of the sphere to prevent gas leakage.

[0032] S4. Gas-liquid separation and product collection The gas-liquid mixture after flash evaporation is introduced into a spiral guide with a spiral angle of 30°. The droplets are removed under the action of the swirl and the dehydrated working liquid is obtained by converging. The steam and carrier gas are discharged from the top of the spiral guide to complete the dehydration.

[0033] Example 3 A method for flash dehydration of a working solution in the production of hydrogen peroxide by anthraquinone, comprising the following steps: S1, waste heat recovery preheating The working fluid to be dehydrated is pumped into the spiral plate heat exchanger, and the waste heat of the outlet liquid of the oxidation process in the anthraquinone process of hydrogen peroxide is used for heat exchange to preheat the working fluid to 71.8°C. The flow rate of the working fluid in the spiral plate heat exchanger is 35m 3 / h, the pressure is 0.8MPa, the flow rate of the oxidation process outlet liquid in the spiral plate heat exchanger is 40m 3 / h, pressure is 1.2MPa.

[0034] S2. Initial dehydration under high gravity A rotating packed bed filled with nickel-based metal foam filler was constructed. Preheated working fluid was sprayed into the rotor cavity from the central axial feed port of the rotating packed bed. The rotor speed was controlled at 3200 rpm, so that the working fluid was radially ejected from the filler and discharged from the packed bed outlet. Undissolved water was captured and collected by the hydrophilic surface of the filler. Among them, the porosity of the nickel-based foam metal filler is about 96%, and the filler is made of foam nickel with a hydroxyapatite coating electrochemically deposited on the surface. The water contact angle θ of the filler surface is about 24.4°, and the preparation method of the nickel-based foam metal filler is: take the foam nickel, immerse it in acetone, and use ultrasonic cleaning with a frequency of 45kHz and a power of 300W for 25 minutes to remove grease, take it out and blow it with nitrogen to dry, then immerse it in a 65°C and 12wt% NaOH solution for 12 minutes to remove the oxide film, take it out and rinse it with deionized water, and then immerse it in a room temperature H2SO4-HNO3 mixed acid with a volume ratio of 3:1 for 120 seconds for surface etching, and then immediately transfer it to deionized water to terminate the reaction, and then take 0.18mol calcium nitrate. / L, 0.12mol / L ammonium dihydrogen phosphate, 0.06mol / L disodium ethylenediaminetetraacetic acid, 0.15mol / L sodium chloride and 6mL / L triethanolamine are mixed and dissolved in deionized water, the pH is adjusted to 9.6, and then stirred at 42°C for 1.5h to obtain an electrochemical deposition solution. Subsequently, electrochemical deposition is carried out using a platinum sheet as an anode and nickel foam as a cathode to deposit a hydroxyapatite coating on the surface of the nickel foam. The current density of the electrochemical deposition is 2.5mA / cm², the temperature is 66°C, and the time is 130min. The thickness of the obtained hydroxyapatite coating is 10±1μm. The nickel foam is then immersed in 85°C deionized water and kept warm for 10h. After being taken out, it is subjected to a vacuum heat treatment at 300°C for 0.8h. Finally, the surface is cleaned to obtain a nickel-based foam metal filler.

[0035] S3, flash deep dehydration Pressure-responsive carrier gas microspheres were added at a dosage of 12 g / L to the working fluid discharged from the packed bed at a temperature of 61.5°C. The working fluid was then introduced into a flash tank with an absolute pressure of 12 kPa. This caused the dissolved water in the working fluid to flash evaporate. Simultaneously, the pressure-responsive carrier gas microspheres shattered under the action of the internal and external pressure differential, causing the internal carrier gas to expand and diffuse, generating an impact airflow that promoted the flash evaporation process. After flash evaporation, a gas-liquid mixture was formed. The density of the pressure-responsive gas-carrying microspheres is 0.910 g / cm 3, the carrier gas pressure is 130kPa; and the preparation method of the pressure-responsive carrier gas microspheres is: porous hollow polylactic acid microspheres are prepared by a template method, specifically: polylactic acid is dissolved in acetonitrile at a ratio of 100mg:22mL to obtain a coating liquid, and then calcium carbonate accounting for 12% of the mass of the polylactic acid is dispersed in the coating liquid, and stirred at 52°C for 25min, followed by centrifugal washing with acetonitrile to obtain polylactic acid microspheres, and then the polylactic acid microspheres are dispersed in 0.25mol / L disodium ethylenediaminetetraacetic acid solution, and vortexed at a speed of 1200r / min for 8h to remove the calcium carbonate template to obtain porous hollow polylactic acid microspheres; and then the porous hollow polylactic acid microspheres are placed in a vacuum chamber The pressure was maintained for 30 minutes to remove residual gas, and then nitrogen was filled into the cavity to 130 kPa and maintained for 6 hours to allow nitrogen to diffuse into the ball through the micropores. Then, while maintaining the pressure unchanged, encapsulation liquid was added into the cavity. The viscosity of the encapsulation liquid was 350 cP, and it was made of an aqueous solution with a mass concentration of 5% polyvinyl alcohol and 10% glycerol. The porous hollow polylactic acid microspheres were immersed in the encapsulation liquid. The encapsulation liquid was then discharged and the cavity was heated to 55°C to dry the porous hollow polylactic acid microspheres, and an encapsulation layer was formed on the surface, thereby obtaining pressure-responsive carrier gas microspheres. The obtained porous hollow polylactic acid microspheres had a diameter of 9±0.4 μm, a wall thickness of 1.5±0.2 μm, and an encapsulation layer thickness of 0.4±0.1 μm.

[0036] S4. Gas-liquid separation and product collection The gas-liquid mixture after flash evaporation is introduced into a spiral guide with a spiral angle of 30°. The droplets are removed under the action of the swirl and the dehydrated working liquid is obtained by converging. The steam and carrier gas are discharged from the top of the spiral guide to complete the dehydration.

[0037] Example 4 like Figure 2 As shown, a dehydration system for implementing the flash dehydration method of the working solution in the anthraquinone method for producing hydrogen peroxide described in Examples 1-3, the dehydration system comprises: The spiral plate heat exchanger module is used to pump the working fluid to be dehydrated into the spiral plate heat exchanger, and utilize the waste heat of the outlet liquid of the oxidation process in the anthraquinone process to preheat the working fluid to 70±2℃; The rotating packed bed module is used to fill nickel-based foam metal fillers. The preheated working fluid is sprayed into the rotor cavity from the central axial feed port of the rotating packed bed. The rotor speed is controlled at 3000-3200 rpm, so that the working fluid is radially ejected from the filler and discharged from the packed bed outlet. The non-dissolved water is captured and collected by the hydrophilic surface of the filler. The flash tank module is used to add pressure-responsive carrier gas microspheres to the working fluid discharged at a temperature of 60±2°C from the outlet of the packed bed, and then introduce the working fluid into the flash tank. The absolute pressure of the flash tank is controlled at 10-12kPa to flash evaporate the dissolved water in the working fluid. At the same time, the pressure-responsive carrier gas microspheres are broken by the internal and external pressure differential, causing the internal carrier gas to expand and diffuse to generate impact airflow to promote the flash evaporation process, forming a gas-liquid mixture after flash evaporation. The spiral deflector module is used to introduce the gas-liquid mixture after flash evaporation into the spiral deflector, remove droplets under the action of swirl, and converge to obtain the dehydrated working liquid, while the steam and carrier gas are discharged from the top of the spiral deflector to complete the dehydration.

[0038] Comparative Example 1 A method for flash dehydration of a working solution in the production of hydrogen peroxide by anthraquinone, comprising the following steps: S1, waste heat recovery preheating Same as Example 2.

[0039] S2, flash deep dehydration The working liquid was cooled to 60.4°C, and pressure-responsive carrier gas microspheres were added to the working liquid at a dosage of 15g / L. The working liquid was then introduced into a flash tank, and the absolute pressure of the flash tank was controlled at 11kPa to cause the dissolved water in the working liquid to flash evaporate. At the same time, the pressure-responsive carrier gas microspheres were broken by the internal and external pressure differential, causing the internal carrier gas to expand and diffuse, generating an impact airflow to promote the flash evaporation process, and forming a gas-liquid mixture after flash evaporation. The density of the pressure-responsive gas-carrying microspheres is 0.908 g / cm 3, the carrier gas pressure is 125kPa; and the preparation method of the pressure-responsive carrier gas microspheres is: porous hollow polylactic acid microspheres are prepared by a template method, specifically: polylactic acid is dissolved in acetonitrile at a ratio of 100mg:20mL to obtain a coating liquid, and then calcium carbonate accounting for 11% of the mass of the polylactic acid is dispersed in the coating liquid, and stirred at 50°C for 30min, followed by centrifugal washing with acetonitrile to obtain polylactic acid microspheres, and then the polylactic acid microspheres are dispersed in 0.22mol / L disodium ethylenediaminetetraacetic acid solution, and vortexed at a speed of 1000r / min for 10h to remove the calcium carbonate template to obtain porous hollow polylactic acid microspheres; and then the porous hollow polylactic acid microspheres are placed in a vacuum chamber The pressure was maintained for 28 minutes to remove residual gas, and then nitrogen was filled into the cavity to 125kPa and maintained for 5.5 hours to allow nitrogen to diffuse into the ball through the micropores. Then, while maintaining the pressure unchanged, encapsulation liquid was added to the cavity. The viscosity of the encapsulation liquid was 300cP, and it was made of an aqueous solution with a mass concentration of 3% polyvinyl alcohol and 8% glycerol. The porous hollow polylactic acid microspheres were immersed in the encapsulation liquid. The encapsulation liquid was then discharged and the cavity was heated to 53°C to dry the porous hollow polylactic acid microspheres, and an encapsulation layer was formed on the surface, thereby obtaining pressure-responsive gas-carrying microspheres. The obtained porous hollow polylactic acid microspheres had a diameter of 9±0.3μm, a wall thickness of 1.5±0.2μm, and an encapsulation layer thickness of 0.4±0.1μm.

[0040] During the preparation of the pressure-responsive gas-carrying microspheres, the surface morphologies of the intermediate porous hollow polylactic acid microspheres and the final product were scanned using a FEI Quanta 200 scanning electron microscope. Figure 1 As shown in the figure, A is the surface micromorphology of the intermediate product porous hollow polylactic acid microspheres, which have uniform pores distributed on the surface, which is conducive to gas penetration. B is the surface micromorphology of the final product pressure-responsive gas-carrying microspheres. It can be seen that the encapsulation layer completely blocks the surface of the sphere to prevent gas leakage.

[0041] S3. Gas-liquid separation and product collection The gas-liquid mixture after flash evaporation is introduced into a spiral guide with a spiral angle of 30°. The droplets are removed under the action of the swirl and the dehydrated working liquid is obtained by converging. The steam and carrier gas are discharged from the top of the spiral guide to complete the dehydration.

[0042] Comparative Example 2 A method for flash dehydration of a working solution in the production of hydrogen peroxide by anthraquinone, comprising the following steps: S1, waste heat recovery preheating Same as Example 2.

[0043] S2. Initial dehydration under high gravity Same as Example 2.

[0044] S3, flash deep dehydration The working fluid with a temperature of 60.4°C discharged from the outlet of the packed bed is directly introduced into the flash tank. The absolute pressure of the flash tank is controlled at 11 kPa to flash evaporate the dissolved water in the working fluid to form a gas-liquid mixture.

[0045] S4. Gas-liquid separation and product collection Same as Example 2.

[0046] Comparative Example 3 A method for flash dehydration of a working solution in the production of hydrogen peroxide by anthraquinone, comprising the following steps: S1, waste heat recovery preheating Same as Example 2.

[0047] S2. Initial dehydration under high gravity Same as Example 2.

[0048] S3, flash deep dehydration Pressure-responsive carrier gas microspheres were added at a dosage of 15 g / L to the working fluid discharged from the packed bed at a temperature of 60.4°C. The working fluid was then introduced into a flash tank with an absolute pressure of 11 kPa. This caused the dissolved water in the working fluid to flash evaporate. Simultaneously, the pressure-responsive carrier gas microspheres shattered under the action of the internal and external pressure differential, causing the internal carrier gas to expand and diffuse, generating an impact airflow that promoted the flash evaporation process. After flash evaporation, a gas-liquid mixture was formed. The density of the pressure-responsive gas-carrying microspheres is 0.759 g / cm 3, the carrier gas pressure is 125kPa; and the preparation method of the pressure-responsive carrier gas microspheres is: porous hollow polylactic acid microspheres are prepared by a template method, specifically: polylactic acid is dissolved in acetonitrile at a ratio of 100mg:20mL to obtain a coating solution, and then calcium carbonate accounting for 13% of the mass of the polylactic acid is dispersed in the coating solution, and stirred at 50°C for 27min, followed by centrifugal washing with acetonitrile to obtain polylactic acid microspheres, and then the polylactic acid microspheres are dispersed in a 0.22mol / L disodium ethylenediaminetetraacetic acid solution, and vortexed at a speed of 1000r / min for 10h to remove the calcium carbonate template to obtain porous hollow polylactic acid microspheres; the porous hollow polylactic acid microspheres are then placed in a vacuum chamber and maintained for 28mi n to remove residual gas, then nitrogen was filled into the cavity to 125kPa and maintained at this pressure for 5.5h to allow nitrogen to diffuse into the sphere through the micropores. Then, while maintaining the pressure, encapsulation liquid was added into the cavity. The viscosity of the encapsulation liquid was 300cP and it was made of an aqueous solution with a mass concentration of 3% polyvinyl alcohol and 8% glycerol. The porous hollow polylactic acid microspheres were immersed in the encapsulation liquid. The encapsulation liquid was then drained and the cavity was heated to 53°C to dry the porous hollow polylactic acid microspheres and form an encapsulation layer on the surface, thereby obtaining pressure-responsive gas-carrying microspheres. The obtained porous hollow polylactic acid microspheres had a diameter of 11±0.3μm (controlled by the particle size of calcium carbonate), a wall thickness of 1.4±0.2μm, and an encapsulation layer thickness of 0.4±0.1μm.

[0049] S4. Gas-liquid separation and product collection Same as Example 2.

[0050] Comparative Example 4 A method for flash dehydration of a working solution in the production of hydrogen peroxide by anthraquinone, comprising the following steps: S1, waste heat recovery preheating Same as Example 2.

[0051] S2. Initial dehydration under high gravity Same as Example 2.

[0052] S3, flash deep dehydration Pressure-responsive carrier gas microspheres were added at a dosage of 15 g / L to the working fluid discharged from the packed bed at a temperature of 60.4°C. The working fluid was then introduced into a flash tank with an absolute pressure of 11 kPa. This caused the dissolved water in the working fluid to flash evaporate. Simultaneously, the pressure-responsive carrier gas microspheres shattered under the action of the internal and external pressure differential, causing the internal carrier gas to expand and diffuse, generating an impact airflow that promoted the flash evaporation process. After flash evaporation, a gas-liquid mixture was formed. The density of the pressure-responsive gas-carrying microspheres is 1.122 g / cm 3, the carrier gas pressure is 125kPa; and the preparation method of the pressure-responsive carrier gas microspheres is: porous hollow polylactic acid microspheres are prepared by a template method, specifically: polylactic acid is dissolved in acetonitrile at a ratio of 100mg:20mL to obtain a coating liquid, and then calcium carbonate accounting for 10% of the mass of the polylactic acid is dispersed in the coating liquid, and stirred at 50°C for 35min, followed by centrifugal washing with acetonitrile to obtain polylactic acid microspheres, and then the polylactic acid microspheres are dispersed in 0.22mol / L disodium ethylenediaminetetraacetic acid solution, and vortexed at a speed of 1000r / min for 10h to remove the calcium carbonate template to obtain porous hollow polylactic acid microspheres; then the porous hollow polylactic acid microspheres are placed in a vacuum chamber and maintained for 28min To remove residual gas, nitrogen was then filled into the cavity to 125 kPa and maintained at this pressure for 5.5 hours, allowing nitrogen to diffuse into the ball through the micropores. Then, while maintaining the pressure, encapsulation liquid was added into the cavity. The viscosity of the encapsulation liquid was 300 cP, and it was made of an aqueous solution with a mass concentration of 3% polyvinyl alcohol and 8% glycerol. The porous hollow polylactic acid microspheres were immersed in the encapsulation liquid. The encapsulation liquid was then discharged and the cavity was heated to 53°C to dry the porous hollow polylactic acid microspheres, and an encapsulation layer was formed on the surface, thereby obtaining pressure-responsive gas-carrying microspheres. The obtained porous hollow polylactic acid microspheres had a diameter of 7.5±0.3 μm (controlled by the particle size of calcium carbonate), a wall thickness of 1.6±0.2 μm, and an encapsulation layer thickness of 0.4±0.1 μm.

[0053] S4. Gas-liquid separation and product collection Same as Example 2.

[0054] Comparative Example 5 A method for flash dehydration of a working solution in the production of hydrogen peroxide by anthraquinone, comprising the following steps: S1, waste heat recovery preheating Same as Example 2.

[0055] S2. Initial dehydration under high gravity Same as Example 2.

[0056] S3, flash deep dehydration Pressure-responsive carrier gas microspheres were added at a dosage of 15 g / L to the working fluid discharged from the packed bed at a temperature of 60.4°C. The working fluid was then introduced into a flash tank with an absolute pressure of 11 kPa. This caused the dissolved water in the working fluid to flash evaporate. Simultaneously, the pressure-responsive carrier gas microspheres shattered under the action of the internal and external pressure differential, causing the internal carrier gas to expand and diffuse, generating an impact airflow that promoted the flash evaporation process. After flash evaporation, a gas-liquid mixture was formed. The density of the pressure-responsive gas-carrying microspheres is 0.905 g / cm 3, the carrier gas pressure is 85kPa; and the preparation method of the pressure-responsive carrier gas microspheres is: porous hollow polylactic acid microspheres are prepared by a template method, specifically: polylactic acid is dissolved in acetonitrile at a ratio of 100mg:20mL to obtain a coating liquid, and then calcium carbonate accounting for 11% of the mass of the polylactic acid is dispersed in the coating liquid, and stirred at 50°C for 30min, followed by centrifugal washing with acetonitrile to obtain polylactic acid microspheres, and then the polylactic acid microspheres are dispersed in 0.22mol / L disodium ethylenediaminetetraacetic acid solution, and vortexed at a speed of 1000r / min for 10h to remove the calcium carbonate template to obtain porous hollow polylactic acid microspheres; and then the porous hollow polylactic acid microspheres are placed in a vacuum chamber The pressure was maintained for 28 minutes to remove residual gas, and then nitrogen was filled into the cavity to 85kPa and maintained for 5.5 hours to allow nitrogen to diffuse into the ball through the micropores. Then, while maintaining the pressure unchanged, encapsulation liquid was added to the cavity. The viscosity of the encapsulation liquid was 300cP, and it was made of an aqueous solution with a mass concentration of 3% polyvinyl alcohol and 8% glycerol. The porous hollow polylactic acid microspheres were immersed in the encapsulation liquid. The encapsulation liquid was then discharged and the cavity was heated to 53°C to dry the porous hollow polylactic acid microspheres, and an encapsulation layer was formed on the surface, thereby obtaining pressure-responsive carrier gas microspheres. The obtained porous hollow polylactic acid microspheres had a diameter of 9±0.3μm, a wall thickness of 1.5±0.2μm, and an encapsulation layer thickness of 0.4±0.1μm.

[0057] S4. Gas-liquid separation and product collection Same as Example 2.

[0058] Comparative Example 6 A method for flash dehydration of a working solution in the production of hydrogen peroxide by anthraquinone, comprising the following steps: S1, waste heat recovery preheating Same as Example 2.

[0059] S2. Initial dehydration under high gravity Same as Example 2.

[0060] S3, flash deep dehydration Pressure-responsive carrier gas microspheres were added at a dosage of 15 g / L to the working fluid discharged from the packed bed at a temperature of 60.4°C. The working fluid was then introduced into a flash tank with an absolute pressure of 11 kPa. This caused the dissolved water in the working fluid to flash evaporate. Simultaneously, the pressure-responsive carrier gas microspheres shattered under the action of the internal and external pressure differential, causing the internal carrier gas to expand and diffuse, generating an impact airflow that promoted the flash evaporation process. After flash evaporation, a gas-liquid mixture was formed. The density of the pressure-responsive gas-carrying microspheres is 0.910 g / cm 3, the carrier gas pressure is 225kPa; and the preparation method of the pressure-responsive carrier gas microspheres is: porous hollow polylactic acid microspheres are prepared by a template method, specifically: polylactic acid is dissolved in acetonitrile at a ratio of 100mg:20mL to obtain a coating liquid, and then calcium carbonate accounting for 11% of the mass of the polylactic acid is dispersed in the coating liquid, and stirred at 50°C for 30min, followed by centrifugal washing with acetonitrile to obtain polylactic acid microspheres, and then the polylactic acid microspheres are dispersed in 0.22mol / L disodium ethylenediaminetetraacetic acid solution, and vortexed at a speed of 1000r / min for 10h to remove the calcium carbonate template to obtain porous hollow polylactic acid microspheres; and then the porous hollow polylactic acid microspheres are placed in a vacuum chamber The pressure was maintained for 28 minutes to remove residual gas, and then nitrogen was filled into the cavity to 225 kPa and maintained for 5.5 hours to allow nitrogen to diffuse into the ball through the micropores. Then, while maintaining the pressure unchanged, encapsulation liquid was added to the cavity. The viscosity of the encapsulation liquid was 300 cP, and it was made of an aqueous solution with a mass concentration of 3% polyvinyl alcohol and 8% glycerol. The porous hollow polylactic acid microspheres were immersed in the encapsulation liquid. The encapsulation liquid was then discharged and the cavity was heated to 53°C to dry the porous hollow polylactic acid microspheres, and an encapsulation layer was formed on the surface, thereby obtaining pressure-responsive gas-carrying microspheres. The obtained porous hollow polylactic acid microspheres had a diameter of 9±0.3 μm, a wall thickness of 1.5±0.2 μm, and an encapsulation layer thickness of 0.4±0.1 μm.

[0061] S4. Gas-liquid separation and product collection Same as Example 2.

[0062] 3. Performance Testing Test method: Karl Fischer method Test instruments and reagents: V20 automatic moisture analyzer; methanol; KF reagent: titer is 2.5 mgH2O / mL.

[0063] Test analysis steps: (1) Adjust the instrument according to the instrument manual, add an appropriate amount of methanol to the titration bottle of the instrument, and titrate the water in the methanol. Take 10uL of pure water and titrate it with Karl Fischer reagent. Calculate the KF reagent titer T as follows:

[0064] (2) Then, add 5 ml of working solution sample (the working solution obtained after treatment in Examples 1-3 and Comparative Examples 1-6) to the titration bottle of the instrument, titrate the water in the sample, and record the consumed Karl Fischer volume V.

[0065] (3) Calculation results: The water content (X) in the working fluid is calculated as follows:

[0066] Where: V1 is the sample volume, unit is mL; V is the volume of Karl Fischer reagent consumed for titration, unit is mL; T is the titration degree of the titrant for pure water, unit is mgH2O / mL.

[0067] 4. Results Analysis The calculation results of the water content of the working fluid are statistically obtained in Table 1 below: Table 1: Water content of working solution after treatment in Examples 1-3 and Comparative Examples 1-6

[0068] As can be seen from Table 1, the water content of the working fluid after the process treatment of Examples 1-3 of the present invention is reduced to below 0.031%, which is far lower than the general requirement of <0.25% in the industry. In particular, Example 2 has a water content as low as 0.024%, which shows an outstanding effect.

[0069] Comparative Examples 1-6 are all single-factor adjustment solutions made on the basis of Example 2, wherein: In Comparative Example 1, the step of high-gravity initial dehydration was omitted, and flash dehydration was performed directly after preheating. As a result, the water content after treatment was 0.179%, and the removal rate was 57.7%, which was significantly lower than that of Example 2. Although it still met the basic requirements of the industry, it inevitably had an impact on the hydrogen peroxide production performance, which also shows the indispensability of high-gravity initial dehydration.

[0070] In the flash dehydration process of Comparative Example 2, no pressure-responsive carrier gas microspheres were added. As a result, the water content after treatment was 0.116%, and the removal rate was 72.6%, which was significantly lower than that of Example 2, indicating that the pressure-responsive carrier gas microspheres had a very significant effect in promoting flash evaporation.

[0071] Comparative Examples 3 and 4 adjusted the overall density of the incorporated pressure-responsive gas-carrying microspheres by process parameters. The density of Comparative Example 3 was 0.759 g / cm 3 , which is significantly smaller than the working fluid density. The density of comparative example 4 is 1.122 g / cm 3 , which is significantly greater than the density of the working fluid. As a result, the water content and removal rate after treatment are significantly reduced compared with those in Example 2, indicating that suitable density is very important for pressure-responsive gas-carrying microspheres. Too heavy or too light will result in the inability to be evenly dispersed and suspended in the working fluid, thereby affecting the effect of the airflow.

[0072] Comparative Examples 5 and 6 adjusted the carrier gas pressure of the added pressure-responsive carrier gas microspheres through process parameters. The pressure in Comparative Example 5 was 85 kPa, and in Comparative Example 6 was 225 kPa. As a result, the water content and removal rate after treatment were significantly reduced compared to Example 2. The reason for this is that the pressure difference of the pressure-responsive carrier gas microspheres during the flash evaporation process in Example 2 was 114 kPa, while the carrier gas pressure in Comparative Example 5 was too small. The pressure difference of the pressure-responsive carrier gas microspheres during the flash evaporation process was too small (74 kPa), resulting in the pressure-responsive carrier gas microspheres being unable to break normally and thus unable to generate airflow. The results also verified that its dehydration effect was basically equivalent to that of Comparative Example 2 without the addition of pressure-responsive carrier gas microspheres. The carrier gas pressure in Comparative Example 6 was too high, resulting in an inappropriate pressure difference during the transportation process (for example, if the transportation pressure was 125 kPa, the pressure difference would be 100 kPa), causing some pressure-responsive carrier gas microspheres to be damaged. In addition, the higher the carrier gas pressure, the higher the requirements for the microsphere preparation process itself, especially the encapsulation process, so the carrier gas pressure needs to be set within a reasonable range.

[0073] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A flash dehydration method for the working solution in the anthraquinone process for producing hydrogen peroxide, characterized in that the steps include: S1, waste heat recovery preheating The working fluid to be dehydrated is pumped into a spiral plate heat exchanger, and the waste heat of the outlet liquid of the oxidation process in the anthraquinone process for hydrogen peroxide production is used for heat exchange, so that the working fluid is preheated to 70±2℃; S2. Initial dehydration under high gravity A rotating packed bed filled with nickel-based metal foam filler was constructed. The preheated working fluid was sprayed into the rotor cavity from the central axial feed port of the rotating packed bed. The rotor speed was controlled at 3000-3200 rpm, so that the working fluid was radially ejected from the filler and discharged from the packed bed outlet. Undissolved water was captured and collected by the hydrophilic surface of the filler. S3, flash deep dehydration Pressure-responsive carrier gas microspheres are added at a dosage of 10-15 g / L to the working fluid discharged from the packed bed at a temperature of 60±2°C. The working fluid is then introduced into a flash tank, and the absolute pressure of the flash tank is controlled at 10-12 kPa to cause flash evaporation of dissolved water in the working fluid. Simultaneously, the pressure-responsive carrier gas microspheres are broken by the internal and external pressure differential, causing the internal carrier gas to expand and diffuse, generating an impact airflow to promote the flash evaporation process, and forming a gas-liquid mixture after flash evaporation. S4. Gas-liquid separation and product collection The gas-liquid mixture after flash evaporation is introduced into the spiral guide, where droplets are removed under the action of cyclone, and the dehydrated working liquid is obtained by converging, while the steam and carrier gas are discharged from the top of the spiral guide to complete the dehydration.

2. The flash dehydration method for the working solution in the anthraquinone process for producing hydrogen peroxide according to claim 1, characterized in that: In step S1, the flow rate of the working fluid in the spiral plate heat exchanger is 25-35m 3 / h, the pressure is 0.5-0.8MPa, the flow rate of the oxidation process outlet liquid in the spiral plate heat exchanger is 30-40m 3 / h, pressure is 1-1.2MPa.

3. The flash dehydration method for the working solution in the anthraquinone process for producing hydrogen peroxide according to claim 1, characterized in that: In step S2, the porosity of the nickel-based foam metal filler is 93-96%, and the filler is made of nickel foam with a hydroxyapatite coating electrochemically deposited on the surface, and the water contact angle θ on the filler surface is less than 25°; The preparation method of the nickel-based foam metal filler is as follows: pre-treating the nickel foam, dissolving calcium nitrate, ammonium dihydrogen phosphate, disodium ethylenediaminetetraacetic acid, sodium chloride and triethanolamine in deionized water, adjusting the pH to 9.5±0.1, stirring at 38-42°C for 1.5-2.5 hours to obtain an electrochemical deposition solution, performing electrochemical deposition with a platinum sheet as an anode and the nickel foam as a cathode to deposit a hydroxyapatite coating on the surface of the nickel foam, immersing the nickel foam in deionized water at 75-85°C for 10-15 hours, taking it out and performing a vacuum heat treatment at 280-300°C for 0.8-1.2 hours, and finally cleaning the surface to obtain the nickel-based foam metal filler.

4. The flash dehydration method for the working solution in the anthraquinone process for producing hydrogen peroxide according to claim 3, characterized in that: The pretreatment includes immersing the nickel foam in acetone and performing ultrasonic cleaning at a frequency of 35-45kHz and a power of 280-300W for 25-30 minutes to remove grease, blowing the nickel foam out with nitrogen for drying, and then immersing the nickel foam in a NaOH solution at a temperature of 55-65°C and a concentration of 8-12wt% for 12-15 minutes to remove the oxide film, rinsing the nickel foam with deionized water, and then immersing the nickel foam in a room temperature H2SO4-HNO3 mixed acid with a volume ratio of 3:1 for 100-120 seconds for surface etching, and then immediately transferring the nickel foam into deionized water to terminate the reaction.

5. The flash dehydration method for the working solution in the anthraquinone process for producing hydrogen peroxide according to claim 3, characterized in that: The concentrations of the components in the electrochemical deposition solution are: 0.16-0.18 mol / L of calcium nitrate, 0.08-0.12 mol / L of ammonium dihydrogen phosphate, 0.04-0.06 mol / L of disodium ethylenediaminetetraacetate, 0.12-0.15 mol / L of sodium chloride, and 4-6 mL / L of triethanolamine.

6. The method for flash dehydration of a working solution in hydrogen peroxide produced by anthraquinone process according to claim 3, characterized in that: The electrochemical deposition process has a current density of 2.5 mA / cm², a temperature of 65±1° C., and a time of 130-150 min. The thickness of the resulting hydroxyapatite coating is 10±1 μm.

7. The flash dehydration method for the working solution in the anthraquinone process for producing hydrogen peroxide according to claim 1, characterized in that: In step S3, the density of the pressure-responsive gas-carrying microspheres is 0.9-0.91 g / cm 3 , carrier gas pressure is 120-130kPa; The preparation method of the pressure-responsive gas-carrier microspheres is as follows: porous hollow polylactic acid microspheres are prepared by a template method, the porous hollow polylactic acid microspheres are placed in a vacuum chamber and maintained for 25-30 minutes to remove residual gas, nitrogen is then filled into the chamber to 120-130 kPa and the pressure is maintained for 5-6 hours to allow the nitrogen to diffuse into the micropores, and then an encapsulation liquid is added to the chamber while maintaining the pressure constant, so that the porous hollow polylactic acid microspheres are immersed in the encapsulation liquid, the encapsulation liquid is then discharged, and the chamber is heated to 52-55° C. to dry the porous hollow polylactic acid microspheres and form an encapsulation layer on the surface, thereby obtaining pressure-responsive gas-carrier microspheres; The porous hollow polylactic acid microspheres have a diameter of 9±0.4 μm, a wall thickness of 1.5±0.2 μm, and an encapsulation layer thickness of 0.4±0.1 μm.

8. The method for flash dehydration of a working solution in hydrogen peroxide produced by anthraquinone process according to claim 7, characterized in that: The specific steps of preparing the porous hollow polylactic acid microspheres are as follows: dissolving polylactic acid in acetonitrile at a ratio of 100 mg:18-22 mL to obtain a coating solution, dispersing calcium carbonate accounting for 10-12% of the mass of the polylactic acid in the coating solution, and stirring at 48-52° C. for 25-35 minutes, followed by centrifugal washing with acetonitrile to obtain polylactic acid microspheres, and then dispersing the polylactic acid microspheres in a 0.18-0.25 mol / L disodium ethylenediaminetetraacetic acid solution, and vortexing and oscillating at a speed of 800-1200 r / min for 8-12 hours to remove the calcium carbonate template to obtain porous hollow polylactic acid microspheres.

9. The method for flash dehydration of a working solution in hydrogen peroxide produced by anthraquinone process according to claim 7, characterized in that: The encapsulation liquid has a viscosity of 250-350 cP and is made of an aqueous solution with a mass concentration of 2-5% polyvinyl alcohol and 5-10% glycerol.

10. A dehydration system for implementing the flash dehydration method for the working solution in the anthraquinone process for producing hydrogen peroxide according to any one of claims 1 to 9, characterized in that: The dehydration system comprises: The spiral plate heat exchanger module is used to pump the working fluid to be dehydrated into the spiral plate heat exchanger, and utilize the waste heat of the outlet liquid of the oxidation process in the anthraquinone process to preheat the working fluid to 70±2℃; The rotating packed bed module is used to fill nickel-based foam metal fillers. The preheated working fluid is sprayed into the rotor cavity from the central axial feed port of the rotating packed bed. The rotor speed is controlled at 3000-3200 rpm, so that the working fluid is radially ejected from the filler and discharged from the packed bed outlet. The non-dissolved water is captured and collected by the hydrophilic surface of the filler. The flash tank module is used to add pressure-responsive carrier gas microspheres at a dosage of 10-15 g / L into the working fluid discharged from the packed bed outlet at a temperature of 60±2°C. The working fluid is then introduced into the flash tank, and the absolute pressure of the flash tank is controlled at 10-12 kPa to cause the dissolved water in the working fluid to flash evaporate. Simultaneously, the pressure-responsive carrier gas microspheres are broken by the internal and external pressure differential, causing the internal carrier gas to expand and diffuse to generate an impact airflow to promote the flash evaporation process, and form a gas-liquid mixture after flash evaporation. The spiral deflector module is used to introduce the gas-liquid mixture after flash evaporation into the spiral deflector, remove droplets under the action of swirl, and converge to obtain the dehydrated working liquid, while the steam and carrier gas are discharged from the top of the spiral deflector to complete the dehydration.

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