Method and system for separating and recycling noble metal catalyst in multi-component organic mixture

Abstract

The invention relates to the technical field of recycling, and particularly provides a method and a system for separating and recycling a noble metal catalyst in a multi-component organic mixture. The separation and recovery method comprises the following steps: carrying out multi-stage separation on a multi-component organic mixture, wherein each stage of separation comprises falling film evaporation separation and rectification separation; sequentially separating the first organic component, the second organic component and the third organic component from the multi-component organic mixture by means of the multi-stage separation; and recovering the residual kettle residue component rich in the noble metal catalyst after the multi-stage separation. According to the method, falling film evaporation separation and rectification purification processes are combined, organic components in the mixture are separated step by step, the noble metal catalyst is concentrated step by step, finally, the organic components and the noble metal catalyst with high purity can be separated and recovered, and the recovery rate of the noble metal catalyst is high.

Description

Technical Field

[0001] This application relates to the field of recycling technology, and in particular to a method and system for separating and recovering precious metal catalysts from multi-component organic mixtures. Background Technology

[0002] Precious metal catalysts (such as platinum, palladium, rhodium, and platinum group metals like ruthenium) are widely used in petrochemicals, pharmaceutical synthesis, automotive exhaust purification, and new energy fields due to their excellent catalytic activity, selectivity, and stability. However, precious metal resources are scarce and expensive, and the limited global reserves contradict the continuous growth in industrial demand; moreover, the recovery cost of traditional precious metal catalysts accounts for more than 30% of the production cost. Against this backdrop, efficient recovery and recycling technologies for precious metal catalysts have become a key link in achieving resource recycling, reducing production costs, and minimizing environmental burden.

[0003] The existing methods for precious metal recovery include the following: (1) Physical separation processes: physical means such as filtration, adsorption, centrifugation, and high-temperature calcination have low metal recovery rates and large losses. (2) Chemical purification processes: traditional hydrometallurgical and pyrometallurgical processes have problems such as high energy consumption, complicated steps, low metal purity (<99.9%), and degradation of heat-sensitive components. (3) Purification and refining processes: such as precipitation and extraction, but these methods have defects such as low separation efficiency and incomplete recovery.

[0004] The existing technologies for purifying liquid organic mixtures mainly include the following processes:

[0005] (1) Falling film evaporation process: It has a wide range of applications and is mainly used in evaporation operations in industries such as chemical, pharmaceutical, food, and metallurgy. It is especially suitable for high-concentration, high-viscosity, and easily crystallizing materials, and reduces the energy consumption of subsequent processing through efficient evaporation. Although it is suitable for heat-sensitive materials, it cannot achieve high-precision separation of multiple components. If the evaporation volume is large, the catalyst may be carried away by the evaporating components and run away, resulting in economic losses.

[0006] (2) Distillation column: It can efficiently separate components, but it has a large pressure drop and high energy consumption when processing high viscosity materials. Continuous distillation column and batch distillation column have lower heat transfer efficiency than falling film evaporation column. Precious metal catalysts are prone to deactivation at high temperature and are more prone to scaling, which increases the difficulty of catalyst recovery.

[0007] Therefore, to purify multi-component products and recover precious metal catalysts for recycling, no single technology can simultaneously meet the requirements of "high-efficiency concentration + high-precision purification." If precious metal catalysts are only recycled without considering reuse, the catalysts need to be collected and processed to reduce them to active catalysts after a period of production, which is time-consuming and costly. Summary of the Invention

[0008] Therefore, the key to this application lies in how to organically integrate the three processes of product purification, catalyst recovery, and catalyst recycling. This application combines the technological characteristics of falling film evaporation and distillation, enabling continuous production throughout the entire process. Simultaneously, while achieving high-efficiency separation of multi-component organic products, it also achieves the goal of catalyst recycling.

[0009] First, this application provides a method for separating and recovering a noble metal catalyst from a multi-component organic mixture, wherein the multi-component organic mixture contains a noble metal catalyst and a first organic component, a second organic component, and a third organic component with sequentially increasing boiling points;

[0010] The recovery method includes: performing multi-stage separation on the multi-component organic mixture, wherein each stage of separation includes falling film evaporation separation and distillation separation; separating the first organic component, the second organic component, and the third organic component sequentially from the multi-component organic mixture through the multi-stage separation; and recovering the residue components rich in precious metal catalyst remaining after the multi-stage separation.

[0011] Preferably, the multi-level separation is a three-level separation, specifically including:

[0012] S1. First-stage separation: The multi-component organic mixture is subjected to a first falling film evaporation separation to obtain a first light component and a first heavy component; the first light component is subjected to a first distillation separation to separate the first organic component and the first bottom feed.

[0013] S2, Second-stage separation: The first heavy component and the first column bottom feed are combined and then subjected to a second falling film evaporation separation to obtain a second light component and a second heavy component; the second light component is subjected to a second distillation separation to separate the second organic component and the second column bottom feed.

[0014] S3, Third-stage separation: The second heavy component and the second column bottom feed are combined and then subjected to third falling film evaporation separation to obtain a third light component and a third heavy component; the third light component is subjected to third distillation separation to separate the third organic component and the third column bottom feed;

[0015] S4. Recover the third heavy component and the third tower bottom feed to obtain the precious metal catalyst.

[0016] Preferably, the boiling point of the first organic component is ≤81℃, the boiling point of the second organic component is greater than 81℃ and less than 150℃, and the boiling point of the third organic component is ≥150℃.

[0017] Preferably, the first falling film evaporation separation is carried out under a vacuum of -20 to -50 kPa and a temperature of 65 to 75°C; the first distillation separation is carried out under a vacuum of -20 to -50 kPa.

[0018] The second falling film evaporation separation is carried out under a vacuum of -20 to -50 kPa and a temperature of 75 to 85 °C; the second distillation separation is carried out under a vacuum of -20 to -50 kPa.

[0019] The third falling film evaporation separation is carried out under vacuum conditions of -85 to -95 kPa and temperature conditions of 80 to 95 °C; the third distillation separation is carried out under vacuum conditions of -85 to -95 kPa.

[0020] Preferably, the material conveying rate in the falling film evaporation separation is 0.3 to 0.6 m³ / h; and / or, the separation and recovery method is carried out in an environment with an oxygen volume content ≤ 0.5%.

[0021] Preferably, before performing a multi-stage separation step on the multi-component organic mixture, the multi-component organic mixture is dissolved in an organic solvent, the organic solvent having a boiling point higher than that of the third organic component, and the organic solvent not affecting the catalytic reaction of the noble metal catalyst.

[0022] Preferably, before performing a multi-stage separation step on the multi-component organic mixture, the multi-component organic mixture is dissolved in an organic solvent, the organic solvent having a boiling point higher than that of the third organic component, and the organic solvent not affecting the catalytic reaction of the noble metal catalyst.

[0023] Preferably, the organic solvent is selected from N-methylpyrrolidone, glycerol, mineral oil, white oil, liquid paraffin, diphenyl ether, dibutyl phthalate, triglyceride, sulfolane, or diphenyl ether.

[0024] Preferably, the first organic component includes one or more of methanol, ethanol, tetrahydrofuran, acetone, n-hexane, cyclohexane, dichloromethane, butene, and hexene;

[0025] The second organic component includes one or more of dichloropentane, n-propanol, isopropanol, toluene, and xylene;

[0026] The third organic component includes one or more of hexachloroethane, N,N-dimethylformamide, dimethyl sulfoxide, ethylene glycol, and glycerol;

[0027] The noble metal catalyst is selected from elements or compounds containing platinum group metals.

[0028] This application also provides a system for separating and recovering noble metal catalysts from multi-component organic mixtures, comprising:

[0029] A multi-stage separation and recovery system includes a first separation and recovery system, a second separation and recovery system, and a third separation and recovery system connected in series. Each separation and recovery system is equipped with a falling film evaporator, a separation chamber, a distillation column, and a reflux tank. The lower end of the falling film evaporator is connected to the separation chamber, the upper end of the separation chamber is connected to the bottom of the distillation column, and the top of the distillation column is connected to the reflux tank.

[0030] A heat supply system is used to provide hot water to the shell side of each falling film evaporator;

[0031] A vacuum system is used to control the vacuum pressure of the multi-stage separation and recovery system;

[0032] The feed control system is used to control the feed rate of each falling film evaporator.

[0033] Preferably, when the liquid level in the separation chamber of the first and second separation and recovery systems reaches 40-50%, the transfer pump is started to transport the material in the separation chamber to the next separation and recovery system.

[0034] The mechanism by which this application achieves the separation and recovery of noble metal catalysts from multi-component organic mixtures is as follows:

[0035] 1. The separation and recovery process in this application consists of a three-stage falling film evaporation section. The falling film evaporator contains multiple thin-film evaporation tubes, with a liquid disperser installed at the top end to ensure the mixture enters each tube uniformly. Hot water is circulated within the evaporator shell as a heat source. The mixture enters from the top of the first-stage evaporator and flows downwards, forming a uniform liquid film on the inner wall of the tubes. This film exchanges heat thoroughly with the hot water in the shell side and evaporates. The vaporized steam, under the influence of gravity and an upstream pump, enters the low-pressure end (i.e., the first separation chamber) for gas-liquid separation. The evaporated light components enter a distillation column from the top of the separation chamber for efficient distillation separation; the heavy components and a small amount of catalyst entrained in the steam fall back into the system; the light components continue to rise in the distillation column, are cooled by heat exchange, and then enter a separation tank for collection. Based on the analysis of the components in the separation tank, they can be returned to the top of the distillation column for further purification or collected downstream via a reflux pump.

[0036] 2. The heavy components at the bottom of the separation chamber are pumped into the next falling film evaporator, with a process similar to that of the first-stage evaporation. After being separated from light components in the second separation chamber, they are pumped into the third-stage evaporator via the second transfer pump. Each component in the mixture is efficiently purified through each falling film stage. Since precious metals cannot be evaporated, each stage of evaporation is equivalent to one concentration.

[0037] 3. Falling film evaporators have a small liquid holdup per unit area in their membrane tubes, resulting in a large heat exchange area and significant evaporation efficiency. Under low vacuum, the boiling points of high-boiling-point organic compounds decrease. Combined with the advantages of falling film evaporators, higher-boiling-point components can be vaporized without requiring excessively high temperatures, meeting separation and purification requirements while protecting the catalyst and saving energy – a triple benefit. When separation efficiency is unsatisfactory or production fluctuates, normal operation can be quickly restored by reducing the feed flow rate or adjusting the liquid level, demonstrating significant operational flexibility and stability.

[0038] 4. Before the multi-component organic mixture is fed into the first falling film evaporator, the multi-component organic mixture is dissolved in an organic solvent, so that the precious metal catalyst is dissolved in it. This can prevent the precious metal from being lost with a large amount of steam during the falling film evaporation process and further improve the recovery effect of the precious metal catalyst.

[0039] Compared with existing technologies, the technical solution of this application has the following advantages:

[0040] High separation efficiency of organic mixtures: This application employs multi-stage separation, with each stage using falling film separation and distillation to sequentially separate the first, second, and third organic components, finally recovering the component containing the precious metal catalyst. In the falling film evaporation separation, the falling film evaporator utilizes the thin-film evaporation principle, where the liquid forms a uniform film flow under gravity, achieving a heat transfer coefficient as high as 1390–2910 W / m²·K, significantly higher than traditional evaporators. Distillation separation can accurately separate different components in the mixture, significantly improving product purity and yield. This method combines the advantages of both separation and purification technologies. By controlling the temperature and pressure of the falling film evaporator, the organic mixture can instantly vaporize and evaporate upon entering, achieving a flash evaporation effect. The removal rate of light components typically reaches 100%, while the small amount of heavy components and trace amounts of precious metal catalyst entrained by the large amount of light components are buffered and cooled by the distillation column and then fall back into the system. This method greatly improves separation efficiency and effectively reduces catalyst loss. Meanwhile, the tower top is also equipped with a reflux line and a production line, allowing for flexible adjustment of the operating method based on the light component index at the tower top.

[0041] The recovered catalyst maintains good activity: After entering the falling film evaporator, the organic mixture descends along the tube wall under gravity, resulting in a short heating time. This effectively prevents heat-sensitive materials from decomposing or deteriorating due to high temperatures. Simultaneously, the low retention rate in the tubes reduces the risk of material and catalyst residue and blockage. The concentrated precious metal catalyst collected from the bottom of the separation chamber in the third separation and recovery system exhibits no significant difference in activity compared to fresh catalyst and can be directly returned to the upstream process for continued catalytic reaction.

[0042] Significant advantages in low energy consumption: Falling film evaporators have high heat transfer efficiency, low temperature difference loss, and short heating time, resulting in lower overall energy consumption than forced circulation evaporators. Their single-pass non-circulating design reduces liquid column static pressure and achieves a higher pure heat temperature difference, further reducing energy consumption. The pressure drop within the evaporator is almost zero, and the tube side operates at atmospheric pressure, effectively reducing energy consumption. Low-calorific-value heat sources (such as dried exhaust gas, warm water, etc.) can be utilized, effectively reducing steam consumption. While distillation columns typically require an external heat source (such as steam, heat transfer oil, etc.) when used alone, this method combines falling film evaporation and distillation processes. The material entering the distillation section is a light component that has already been vaporized by the falling film evaporator, thus eliminating the need for secondary vaporization with an external heat source, effectively reducing energy consumption.

[0043] Good economic performance over long-term operation: The initial investment for this process is relatively high, mainly due to the input of falling film evaporators, distillation columns, and precious metal catalysts. However, it has economic advantages in the long run. These advantages are mainly reflected in the following aspects: a) The entire process can be operated continuously with upstream and downstream components. The precious metal catalyst recovered from the falling film process maintains good activity and can be directly returned to the upstream reaction, eliminating the precious metal catalyst recovery and regeneration process in traditional processes. The unit can operate without interruption, significantly improving the effective output rate. Therefore, only the minimum amount of precious metal catalyst required to ensure the stability of the upstream reaction needs to be added in the initial stage of startup. b) Low energy consumption, resulting in more advantageous operating costs.

[0044] Furthermore, by introducing a high-boiling-point solvent (such as sulfolane) and a multi-stage falling film evaporation-distillation coupling process, this application has for the first time achieved efficient separation and in-situ reuse of noble metal catalysts in multi-component organic mixtures. Compared with single falling film evaporation or distillation processes, this application has significant technical advantages in the following aspects: catalyst recovery rate ≥99.9% and activity retention rate ≥98%; separation purity ≥99.5%, meeting the reuse standards for most organic synthesis reactions; energy consumption reduced by 20%~30%, thanks to the thermal coupling design of falling film evaporation and distillation; system oxygen content controlled ≤0.5%, ensuring the structural stability of the thermosensitive catalyst. Attached Figure Description

[0045] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some implementation methods of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0046] Figure 1 This is a schematic diagram of the workflow of a multi-stage separation and recycling system used in one embodiment of this application.

[0047] Figure Labels

[0048] 1. First falling film evaporator; 2. Second falling film evaporator; 3. Third falling film evaporator; 4. First distillation column; 5. Second distillation column; 6. Third distillation column; 7. First separation chamber; 8. Second separation chamber; 9. Third separation chamber; 10. First condenser; 11. Second condenser; 12. Third condenser; 13. First reflux tank; 14. Second reflux tank; 15. Third reflux tank; 16. First transfer pump; 17. Second transfer pump; 18. Third transfer pump; 19. First vacuum pump; 20. Second vacuum pump; 21. Third vacuum pump; 22. First reflux pump; 23. Second reflux pump; 24. Third reflux pump. Detailed Implementation

[0049] The embodiments described in this specification are merely for explaining this application and are not intended to limit this application.

[0050] For simplicity, this paper only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an undefined range; and any lower limit can be combined with other lower limits to form an undefined range, just as any upper limit can be combined with any other upper limit to form an undefined range. Furthermore, although not explicitly stated, every point or individual value between the endpoints of a range is included within that range. Therefore, each point or individual value can serve as its own lower or upper limit and be combined with any other point or individual value, or with other lower or upper limits, to form an undefined range.

[0051] In one embodiment of this application, a method for separating and recovering a noble metal catalyst from a multi-component organic mixture is provided, wherein the multi-component organic mixture contains a noble metal catalyst and a first organic component, a second organic component, and a third organic component with sequentially increasing boiling points.

[0052] The recovery method includes: performing multi-stage separation on the multi-component organic mixture, wherein each stage of separation includes falling film evaporation separation and distillation separation; separating the first organic component, the second organic component and the third organic component sequentially from the multi-component organic mixture through multi-stage separation; and recovering the residue components rich in precious metal catalyst remaining after multi-stage separation.

[0053] In some embodiments, multi-level separation is three-level separation, specifically including:

[0054] S1. First-stage separation: The multi-component organic mixture is subjected to a first falling film evaporation separation to obtain a first light component and a first heavy component; the first light component is subjected to a first distillation separation to separate the first organic component and the first bottom feed.

[0055] S2, Second-stage separation: The first heavy component and the first column bottom feed are combined and then subjected to a second falling film evaporation separation to obtain a second light component and a second heavy component; the second light component is then subjected to a second distillation separation to separate a second organic component and a second column bottom feed.

[0056] S3, Third-stage separation: The second heavy component and the second column bottom feed are combined and then subjected to third falling film evaporation separation to obtain the third light component and the third heavy component; the third light component is then subjected to third distillation separation to separate the third organic component and the third column bottom feed;

[0057] S4. The third heavy component and the bottom feed of the third tower are recovered to obtain the precious metal catalyst.

[0058] In some embodiments, the boiling point of the first organic component is ≤81℃, the boiling point of the second organic component is greater than 81℃ and less than 150℃, and the boiling point of the third organic component is ≥150℃.

[0059] In some embodiments, the boiling point of the first organic component is 40~81℃, the boiling point of the second organic component is 82~145℃, and the boiling point of the third organic component is 150~200℃.

[0060] In some embodiments, the first falling film evaporation separation is carried out under a vacuum of -20 to -50 kPa and a temperature of 65 to 75°C; the first distillation separation is carried out under a vacuum of -20 to -50 kPa.

[0061] In some embodiments, the second falling film evaporation separation is carried out under a vacuum of -20 to -50 kPa and a temperature of 75 to 85°C; the second distillation separation is carried out under a vacuum of -20 to -50 kPa.

[0062] In some embodiments, the third falling film evaporation separation is carried out under a vacuum of -85 to -95 kPa and a temperature of 80 to 95 °C; the third distillation separation is carried out under a vacuum of -85 to -95 kPa.

[0063] In some embodiments, the material conveying rate in falling film evaporation separation is 0.3 to 0.6 m³ / h.

[0064] In some embodiments, the separation and recovery method is carried out in an environment with an oxygen volume content ≤0.5%.

[0065] In some embodiments, prior to the multi-component organic mixture undergoing a multi-stage separation step, the multi-component organic mixture is dissolved in an organic solvent with a boiling point higher than that of the third organic component, and the organic solvent does not affect the catalytic reaction of the noble metal catalyst.

[0066] In some embodiments, the organic solvent is selected from N-methylpyrrolidone, glycerol, mineral oil, white oil, liquid paraffin, diphenyl ether, dibutyl phthalate, triglyceride, sulfolane, or diphenyl ether.

[0067] In some embodiments, the first organic component includes one or more of methanol, ethanol, tetrahydrofuran, acetone, n-hexane, cyclohexane, dichloromethane, butene, and hexene.

[0068] In some embodiments, the second organic component includes one or more of dichloropentane, n-propanol, isopropanol, toluene, and xylene.

[0069] In some embodiments, the third organic component includes one or more of hexachloroethane, N,N-dimethylformamide, dimethyl sulfoxide, ethylene glycol, and glycerol.

[0070] In some embodiments, the noble metal catalyst is selected from elements or compounds containing platinum group metals (including coordination compounds formed by their combination with organophosphorus ligands). Noble metal catalysts include, but are not limited to, elements, oxides, metal salts, or other forms of compounds of platinum group metals, including platinum, palladium, osmium, iridium, ruthenium, and rhodium, such as RuO2, Rh2O3, PdO, OsO2, IrO2, PtO2, RuCl3·xH3O, [Ru(NO)(NO3)3], RhCl3·xH2O, Rh(NO3)3, and Rh4(CO). 12 , PdCl2, Pd(NO3)2, Pd(OAc)2, H2PtCl2, etc.

[0071] In some embodiments, the multi-component organic mixture is derived from reactants in cross-coupling reactions; for example, reactants in cross-coupling reactions of olefins and halogenated aromatics, cross-coupling reactions of arylboronic acids and halogenated aromatics, hydrogenation reactions, hydroformylation reactions of olefins reacting with syngas CO / H2 to produce aldehydes, CH bond activation reactions, metathesis reactions of olefins to construct C=C double bonds, oxidation reactions, carbonylation reactions of methanol carbonylation to produce acetic acid, asymmetric catalytic reactions, dehydrogenation reactions, and hydrosilylation reactions.

[0072] In one embodiment, this application provides a separation and recovery system for noble metal catalysts in a multi-component organic mixture, comprising: a multi-stage separation and recovery system, the multi-stage separation and recovery system including a first separation and recovery system, a second separation and recovery system and a third separation and recovery system connected in series, each separation and recovery system being equipped with a falling film evaporator, a separation chamber, a distillation column and a reflux tank, wherein the lower end of the falling film evaporator is connected to the separation chamber, the upper end of the separation chamber is connected to the bottom of the distillation column, and the top of the distillation column is connected to the reflux tank;

[0073] A heat supply system is used to provide hot water to the shell side of each falling film evaporator;

[0074] Vacuum system, used to control the vacuum pressure of multi-stage separation and recovery system;

[0075] The feed control system is used to control the feed rate of each falling film evaporator.

[0076] See Figure 1 In one embodiment, the first separation and recovery system includes a first falling film evaporator 1, a first separation chamber 7, a first distillation column 4, and a first reflux tank 13. The lower end of the first falling film evaporator 1 is connected to the first separation chamber 7, the upper end of the first separation chamber 7 is connected to the bottom of the first distillation column 4, and the top of the first distillation column 4 is connected to the first reflux tank 13. After the first evaporation separation in step S1, the first light component and the first heavy component enter the first separation chamber 7 at the low-pressure end. Then, the first light component continues to rise to the first distillation column 4 for the first distillation separation. During the first distillation separation, the sediment in the bottom of the column falls back into the first separation chamber 7 and mixes with the first heavy component. The top fraction with the first boiling point is condensed and recovered into the first reflux tank 13.

[0077] Preferably, the top of the first distillation column 4 is connected to the first reflux tank 13 via a connecting pipe. A first condenser 10 is provided outside the connecting pipe. The top distillate with the first boiling point is condensed into a liquid state by the heat exchange of the first condenser 10 and then returned to the first reflux tank 13 for storage.

[0078] In one embodiment, the second separation and recovery system includes a second falling film evaporator 2, a second separation chamber 8, a second distillation column 5, and a second reflux tank 14; the connection method of the second falling film evaporator 2, the second separation chamber 8, the second distillation column 5, and the second reflux tank 14 is the same as the connection method of the first falling film evaporator 1, the first separation chamber 7, the first distillation column 4, and the first reflux tank 13 in the first separation and recovery system. After the second evaporation separation in step S2, the second light component and the second heavy component enter the second separation chamber 8 at the low-pressure end, and then the second light component continues to rise to the second distillation column 5 for the second distillation separation; the sediment in the bottom of the column during the second distillation separation falls back into the second separation chamber 8 and mixes with the second heavy component, and the top fraction with the second boiling point is condensed and recovered to the second reflux tank 14.

[0079] Preferably, the top of the second distillation column 5 is connected to the second reflux tank 14 via a connecting pipe. A second condenser 11 is installed outside the connecting pipe. The top distillate with the second boiling point is condensed into a liquid state by the heat exchange of the second condenser 11 and then refluxed back to the second reflux tank 14 for storage.

[0080] In one embodiment, the third separation and recovery system includes a third falling film evaporator 3, a third separation chamber 9, a third distillation column 6, and a third reflux tank 15; the connection method of the third falling film evaporator 3, the third separation chamber 9, the third distillation column 6, and the third reflux tank 15 is the same as the connection method of the first falling film evaporator 1, the first separation chamber 7, the first distillation column 4, and the first reflux tank 13 in the first separation and recovery system. After the third evaporation separation in step S3, the third light component and the third heavy component enter the third separation chamber 9 at the low-pressure end, and then the third light component continues to rise to the third distillation column 6 for third distillation separation; the sediment in the bottom of the column during the third distillation separation falls back into the third separation chamber 9 and mixes with the third heavy component, and the top fraction with the third boiling point is condensed and recovered into the third reflux tank 15.

[0081] Preferably, the top of the third distillation column 6 is connected to the third reflux tank 15 via a connecting pipe. A third condenser 12 is installed outside the connecting pipe. The top distillate with the third boiling point is condensed into a liquid state by the heat exchange of the third condenser 12 and then refluxed back to the third reflux tank 15 for storage.

[0082] Preferably, the first separation chamber 7 in the first separation and recovery system is connected to the upper end of the second falling film evaporator 2 in the second separation and recovery system via a pipeline, on which a first transfer pump 16 is installed. The mixture in the first separation chamber 7 is transported to the second falling film evaporator by the first transfer pump 16 for a second evaporation and separation.

[0083] Preferably, the second separation chamber 8 in the second separation and recovery system is connected to the upper end of the third falling film evaporator in the third separation and recovery system via a pipeline, on which a second transfer pump 17 is installed. The mixture in the second separation chamber 8 is transported to the third falling film evaporator by the second transfer pump 17 for third evaporation and separation.

[0084] Preferably, the lower end of the third separation chamber 9 is connected to a downstream device via a pipeline, on which a third transfer pump 18 is installed. The third transfer pump 18 can transport the material in the third separation chamber 9 to the downstream device.

[0085] In some embodiments, when the liquid level in the separation chamber of the first separation and recovery system and the second separation and recovery system reaches 40% to 50%, the transfer pump is started to transport the material in the separation chamber to the next separation and recovery system.

[0086] As an example, when the liquid level in the first separation chamber 7 reaches 40% to 50%, the first transfer pump 16 is started to transport the mixture of the first heavy component and the first tower bottom feed to the second falling film evaporator 2.

[0087] When the liquid level in the second separation chamber 8 reaches 40%–50%, the second transfer pump 17 is started to transport the mixture of the second heavy component and the bottom feed of the second tower to the third falling film evaporator 3. By controlling the mixture in the separation chamber to reach a specific liquid level before starting the transfer pump, the mixture to be separated and recovered is transferred to the upstream reactor for use.

[0088] In some embodiments, when the mass content of the first organic component in the overhead fraction obtained after the first distillation separation is less than 99%, the overhead fraction is refluxed, with the reflux ratio controlled at 0~2. Reflux can further improve the purity of the recovered first organic component.

[0089] In some embodiments, when the liquid level in the first reflux tank 13 reaches 20%, a sample is taken for analysis. If the mass content of the first organic component in the liquid in the first reflux tank 13 is ≥99%, it is transported to the downstream storage tank by a reflux pump. If the mass content of the first organic component is <99%, the reflux ratio is increased and the liquid is refluxed to the top of the first distillation column 4, and the reflux ratio is controlled to be 0~2.

[0090] Preferably, the liquid in the first reflux tank 13 is transported to the downstream storage tank by the first reflux pump 22, or refluxed back to the top of the first distillation column 4.

[0091] In some embodiments, when the liquid level in the second reflux tank 14 reaches 20%, a sample is taken for analysis. When the mass content of the second organic component in the liquid in the second reflux tank 13 is ≥99%, it is transported to the downstream storage tank by the second reflux pump 23. When the mass content of the second organic component is <99%, the reflux ratio is increased and the liquid is refluxed to the top of the second distillation column 5, and the reflux ratio is controlled to be 0~2.

[0092] Preferably, the liquid in the second reflux tank 14 is transported to the downstream storage tank by the second reflux pump 23, or refluxed to the top of the second distillation column 5.

[0093] In some embodiments, when the mass content of the second organic component in the overhead fraction obtained after the second distillation is less than 99%, the overhead fraction is refluxed, and the reflux ratio is controlled to be 0~2.

[0094] In some embodiments, when the liquid level in the third reflux tank 15 reaches 20%, a sample is taken for analysis. When the mass content of the third organic component in the liquid in the third reflux tank 15 is ≥99%, it is transported to the downstream storage tank by a reflux pump. When the mass content of the third organic component is <99%, the reflux ratio is increased and the liquid is refluxed to the top of the third distillation column 6, and the reflux ratio is controlled to be 0~2.

[0095] Preferably, the liquid in the third reflux tank 15 is transported to the downstream storage tank by the third reflux pump 24, or refluxed to the top of the third distillation column 6.

[0096] In some embodiments, when the mass content of the second organic component in the overhead fraction obtained after the third distillation is less than 99%, the overhead fraction is refluxed, and the reflux ratio is controlled to be 0~2.

[0097] In some embodiments, the first reflux tank 13 is connected to the first vacuum pump 19; before the multi-component organic mixture is delivered to the first falling film evaporator 1, the vacuum pump is started to bring the internal cavity gas pressure of the first falling film evaporator 1, the first separation chamber 7 and the first distillation column 4 to the working gas pressure.

[0098] In some embodiments, the second reflux tank 14 is connected to the second vacuum pump 20; before the mixture formed by the first heavy component and the first column bottom feed is delivered to the second falling film evaporator 2, the vacuum pump is started to bring the internal cavity gas pressure of the second falling film evaporator 2, the second separation chamber 8 and the second distillation column 5 to the working gas pressure.

[0099] In some embodiments, the third reflux tank 15 is connected to the third vacuum pump 21; before the mixture formed by the second heavy component and the second column bottom material is transported to the third falling film evaporator 3, the vacuum pump is started to bring the internal cavity gas pressure of the third falling film evaporator 3, the third separation chamber 9 and the third distillation column 6 to the working gas pressure.

[0100] In some embodiments, the heat medium introduced into the first falling film evaporator 1, the second falling film evaporator 2, and the third falling film evaporator 3 is water, and the heat medium enters from the lower end inlet and exits from the upper end outlet.

[0101] In some embodiments, the separation and recovery system also includes an oxygen content detection device for monitoring the oxygen content within the system.

[0102] In some embodiments, when separating and recovering precious metal catalysts from multi-component organic mixtures, the oxygen volume content in the multi-stage separation and recovery system is ≤0.5%.

[0103] The present application is further illustrated below with reference to embodiments. It should be understood that these embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0104] The bottom feed material discharged from catalytic reactions using precious metal catalysts typically contains both low-boiling-point organic compounds (alcohols, aldehydes) and high-boiling-point organic compounds (ethers, higher-carbon alkanes, etc.). The composition of the recoverable mixture used in the examples and comparative examples of this application is: 14.86% 1-hexene, 55.55% toluene, 0.24% tris(2,4-di-tert-butylphenyl)phosphonite, 0.02% tetrarhodium dodecylcarbonyl, and 29.31% heptanal.

[0105] Example 1

[0106] See Figure 1 ,exist Figure 1 The system shown separates and recovers platinum group metal catalysts from the mixture using the following method:

[0107] S1: Before feeding the system, use nitrogen to fully purge the system to ensure that the oxygen content is <0.5%.

[0108] S2: Hot water at 70°C is introduced into the first falling film evaporator (1), hot water at 75°C is introduced into the second falling film evaporator (2), and hot water at 85°C is introduced into the third falling film evaporator (3).

[0109] S3: Start the first vacuum pump (19) and control the vacuum degree of the first separation and recovery system to -20KPa; start the second vacuum pump (20) and control the vacuum degree of the second separation and recovery system to -20KPa; start the third vacuum pump (21) and control the vacuum degree of the third separation and recovery system to -90KPa.

[0110] S4: Start the upstream feed pump and control the feed flow rate of the first falling film evaporator 1 to 0.6 m³ / s. 3 / h; The mixture enters from the top of the first falling film evaporator (1) and flows from top to bottom, forming a uniform liquid film on the inner wall of the tube. It fully exchanges heat with the hot water in the shell side and evaporates. The vaporized steam enters the low-pressure end under the action of gravity and the upstream delivery pump, and enters the first separation chamber (7) for gas-liquid separation. The evaporated light component enters the first distillation column (4) section from the top of the first separation chamber (7) for efficient separation; the heavy component and a small amount of entrained catalyst fall back to the bottom of the first separation chamber (7). The temperature at the top of the first distillation column (4) is 69°C and the reflux ratio is 1. The light component in the column continues to rise and is cooled by the first condenser (10) before entering the first reflux tank (13) for collection.

[0111] S5: The first reflux tank (13) is set to 20% liquid level, and samples are taken for analysis. The first light component is collected by pumping it out through the first reflux pump (22).

[0112] S6: Establish a liquid level of 40% to 50% in the first separation chamber (7), start the first transfer pump (16), and transport the mixed liquid in the first separation chamber (7) to the second falling film evaporator (2), controlling the flow rate to 0.5 m³ / s. 3 / h, for separation and recovery; wherein, the top temperature of the second distillation column (5) is 73℃.

[0113] S7: The second reflux tank (14) is set to 20% liquid level, and samples are taken for analysis. The second reflux pump collects the samples externally.

[0114] S8: Establish a liquid level of 40% to 50% in the second separation chamber (8), start the second transfer pump (17) to feed the third falling film evaporator (3), and control the flow rate to 0.5 m³ / h. 3 / h; separation and recovery are carried out; among them, the top temperature of the third distillation column (6) is 82℃.

[0115] Note: Oxygen content is sampled and analyzed from the outlet of each vacuum pump every 24 hours to ensure that the system is oxygen-free.

[0116] Examples 2-3

[0117] The separation and recovery methods in Examples 2 and 3 are basically the same as those in Example 1. The main difference is that the parameter settings of each device are different. The parameter setting conditions for each Example 2 and 3 are shown in Table 1.

[0118] Examples 4-6: Solvent introduction method

[0119] The composition of the mixture to be recovered in Examples 4-6 is as follows: 14.28% 1-hexene, 45.62% toluene, 0.23% tris(2,4-di-tert-butylphenyl)phosphonite, 0.03% tetrarhodium dodecylcarbonyl, 29.43% heptanal, and 10.02% sulfolane.

[0120] The specific separation and recovery steps and parameters of the mixture after the addition of sulfolane solvent in Example 4 are basically the same as those in Example 1. The main difference is that no reflux treatment was performed in the third distillation column.

[0121] Example 5 follows the same separation and recovery steps and parameters as Example 4 for the mixture after the addition of sulfolane solvent. The main difference is that the parameters of each device are set differently. The specific parameter settings are shown in Table 1.

[0122] Example 6 follows the same separation and recovery steps and parameters as Example 4 for the mixture after the addition of sulfolane solvent. The main difference is that the parameters of each device are set differently. The specific parameter settings are shown in Table 1.

[0123] Comparative Examples 1-3

[0124] The preparation methods of Comparative Examples 1 to 3 are basically the same as those of Example 1. The only difference is that the vacuum degree and temperature conditions in each falling film evaporator are different. The specific parameter settings are shown in Table 1. Other parameters are the same as those in Example 1.

[0125] Test Analysis:

[0126] The components in each separation chamber and reflux tank of Examples 1-6 and Comparative Examples 1-3 were analyzed, and the mass contents of 1-hexene, toluene, heptanal, and sulfolane in the liquid of each separation chamber and reflux tank were calculated. The content of the noble metal catalyst was also calculated. The specific test results are shown in Tables 2 and 3.

[0127] The evaporation rate of the third-stage falling film evaporator in the third separation and recovery system of Examples 1-6 was recorded, and the specific results are shown in Table 4.

[0128] Table 1. Parameter settings for each separation stage in Examples 1-6 and Comparative Examples 1-3

[0129]

[0130] Table 2 shows the organic component content in the separation chambers and reflux tanks of Examples 1-6 and Comparative Examples 1-3.

[0131]

[0132] Note: In Table 2, the content of each organic component in each separation chamber or reflux tank refers to the mass percentage of the organic component with the total mass of the solution in the corresponding separation chamber or reflux tank being 100%; for example, in Example 1 of Table 2, the mass content of 1-hexene in the first separation chamber refers to the mass content of 1-hexene being 14% with the total mass of the solution in the first separation chamber being 100%.

[0133] Table 3. Recovery of rhodium in the solutions of each separation chamber and reflux tank in Examples 1-6 and Comparative Examples 1-3.

[0134]

[0135] Table 4. Evaporation Statistics of the Third Separation and Recovery System in Examples 1-6

[0136]

[0137] The relative improvement rate in Table 4 refers to the improvement rate of the evaporation amount of the third-stage separation section in the example with added sulfolane compared to the evaporation amount of the third-stage separation section in the example without added sulfolane. The calculation method is: relative improvement rate = (evaporation amount of the third-stage separation section in the example with added sulfolane - evaporation amount of the third-stage separation section in the example without added sulfolane) / evaporation amount of the third-stage separation section in the example without added sulfolane * 100%. For example, the relative improvement rate of the evaporation amount of the third-stage separation section in Example 4 compared to the evaporation amount of the third-stage separation section in Example 1 is calculated as: (0.2 - 0.1) / 0.1 * 100% = 100%.

[0138] Analysis of the data in Tables 1 to 4 shows that the technical solution of this application combines falling film evaporation and distillation processes to achieve complete recovery of the rhodium catalyst, and the operating conditions of this process are mild. Combined with a multi-stage separation and recovery system, this method can achieve continuous production throughout the entire process, while meeting the requirements of efficient separation of multi-component organic materials and realizing the recovery and recycling of solvents and catalysts.

[0139] Furthermore, comparing Examples 1-3 with Examples 4-6, in Examples 4-6, the fractions in the distillation column were not refluxed during separation and recovery in the third separation and recovery system. Because there was no cold feed reflux to suppress the rising vapor in the distillation column, the evaporation rate in the third distillation column of Examples 4-6 increased by approximately 20%. Generally, increased evaporation rate leads to increased entrainment of precious metals, resulting in increased precious metal loss. However, the data in Table 3 shows that no precious metal components were found in the third reflux tank of Examples 4-6. This indicates that after the introduction of sulfolane, the catalyst can dissolve well in it and will not be lost with a large amount of evaporated material, thus preventing catalyst entrainment.

[0140] In summary, the solvent introduction method can increase the processing load of the falling film evaporation system. Compared with the embodiment without solvent introduction, its relative evaporation capacity is increased by 25-100%, and no reflux is required in the third separation and recovery system, thus resulting in lower energy consumption over long-term operation. However, this method requires careful consideration of whether the upstream catalyst reaction unit can introduce suitable heavy component solvents. If no suitable additives are available, it can also be applied in practice according to the process without introducing additional high-boiling-point solvents.

[0141] The following are experimental examples comparing the activity of fresh catalyst and recycled catalyst.

[0142] Using 1-hexene as a starting material for the carbonylation to prepare n-heptaldehyde as a model reaction, the catalyst's reactivity and changes in selectivity for the target product were evaluated based on the conversion rate of the starting material, the selectivity of the target product, and the ratio of straight-chain to branched-chain heptaldehyde in the target product. This determined the effectiveness of the catalyst's chemical structure. The preparation steps for n-heptaldehyde using 1-hexene as a starting material are as follows:

[0143] 0.1 mol of 1-hexene was dissolved in 100 mL of toluene. Based on the molar content of rhodium, 0.015 mmol of a fresh tetrarhodium dodecylcarbonyl-organophosphine ligand catalyst or the recovered tetrarhodium dodecylcarbonyl-organophosphine ligand catalyst from Example 1 was added, and the reaction was carried out at 100 °C and 2 MPa. The conversion rate of the starting material and the selectivity of the target product were recorded. The specific results are shown in Table 5 below.

[0144] Table 5. Experimental data for the catalyst-catalyzed carbonylation of 1-hexene to prepare n-heptaldehyde in each experimental example.

[0145]

[0146] Analysis of the data in Table 5 above shows that the catalytic effect of the recovered catalyst in Example 1 is comparable to that of the new catalyst. It can be considered that the recovered catalyst has good activity and the coordination structure of the catalyst is well maintained.

[0147] Control Group 1: Multi-stage Falling Film Evaporation System Process

[0148] This control group included two examples: Control Group 1-1 and Control Group 1-2. Each example employed a multi-stage falling film evaporation process. The main difference between this process and Example 1 is that the distillation column is omitted in this process; the upper end of the separation chamber is directly connected to the reflux tank. Other equipment and connection methods are the same as in the multi-stage falling film evaporation system used in Example 1. The specific steps are as follows:

[0149] S1: Before feeding the system, use nitrogen to fully purge the system to ensure that the oxygen content is <0.5%.

[0150] S2: Hot water at 65~70℃ is introduced into the first falling film evaporator, hot water at 75~80℃ is introduced into the second falling film evaporator, and hot water at 80~85℃ is introduced into the third falling film evaporator.

[0151] S3: Start the first vacuum pump and control the vacuum level of the first-stage separation and recovery system to -20kPa; start the second vacuum pump and control the vacuum level of the second-stage separation and recovery system to -20kPa; start the third vacuum pump and control the vacuum level of the third falling film evaporation system to -80kPa.

[0152] S4: Start the upstream feed pump and control the feed flow rate of the first falling film evaporator to 0.6 m³ / h. 3 When the liquid level in the separation chamber reaches 40%–50% per hour, start the first feed pump to feed the second falling film evaporator, controlling the flow rate at 0.5 m³ / h. 3 / h.

[0153] S5: The first reflux tank is set to 20% liquid level, samples are taken for analysis, and the first light component is collected externally by the pump.

[0154] S6: Establish a liquid level of 40%–50% in the second separation chamber, start the second transfer pump to feed the third falling film evaporator, and control the flow rate at 0.5 m³ / h. 3 / h.

[0155] S7: The second reflux tank is set to 20% liquid level for sampling and analysis, and the second light component is collected externally by the pump.

[0156] S8: Establish a liquid level of 20%–30% in the third separation chamber, start the third transfer pump to discharge to the collection tank or return to the upstream reaction system, controlling the flow rate at 0.2–0.3 m³ / h. 3 / h.

[0157] S9: The third reflux tank is set to 20% liquid level for sampling and analysis, and the third-stage light component is collected externally by the pump.

[0158] Note: Oxygen content is sampled and analyzed from the vacuum pump outlet every 24 hours to ensure that the system is oxygen-free.

[0159] The parameter settings for each control group are shown in Table 6:

[0160] Table 6 Parameter settings for each control group

[0161]

[0162] Test Analysis:

[0163] The components in each separation chamber and reflux tank of control groups 1-1 to 1-2 were analyzed, and the mass contents of 1-hexene, toluene, heptanal, and sulfolane in the liquid of each separation chamber and reflux tank were calculated. The content of rhodium was also calculated. The specific test results are shown in Tables 7 and 8.

[0164] Table 7. Analysis of Organic Components in Falling Film Evaporation at Various Levels

[0165]

[0166] Table 8. Analysis of Rhodium Content in Falling Film Evaporation at Various Levels

[0167]

[0168] Data from Tables 6-8 show that under the same operating conditions, the evaporation rate of each stage of the falling film evaporator increases with increasing temperature. Comparative Examples 1-2 show the optimal temperature, where the evaporation rate of each component in the mixed composition reaches the theoretical value of its content percentage. However, analysis of Table 7 indicates that the separation and purification effect of each component is not ideal. 1-Hexene was detected in the reflux tank of the first falling film evaporator system, and toluene was detected in the reflux tank of the second falling film evaporator system, with their proportion increasing with increasing temperature, far from the target of high-efficiency separation (>99%). Analysis of the data in Table 8 shows that a large amount of rhodium was detected in the reflux tanks of the first, second, and third falling film evaporators. The likely reason for this is the high evaporation rate in each stage of the falling film evaporator, which causes some rhodium catalyst to be carried out of the system by a large amount of vaporized components. Furthermore, the higher the temperature, the greater the vaporization rate, and the more catalyst is lost. This lost catalyst cannot be returned to the system, thus causing direct economic losses. In summary, the advantages of traditional falling film evaporation are a large effective heat exchange area and high evaporation efficiency; however, its disadvantages are also obvious: poor separation of components and large metal entrainment.

[0169] Control group 2: Pure multi-stage distillation column process

[0170] This comparative experiment designed a control experiment for a distillation column process. Three continuous distillation columns were designed, abbreviated as T-01, T-02, and T-03. Hot water was used as the heat source, and structured packing was used on the trays. A heat exchanger at the top of each column was connected to a vacuum pump, allowing for adjustable vacuum levels. Lighter components, cooled by the heat exchanger at the top, were collected in a reflux tank. The heavier components were collected at the bottom of the columns. The lighter components could be returned to the column via the reflux pump or collected externally. The heavier components at the bottom of the columns, after being separated from the lighter components, were transferred to the next distillation column for purification via a bottom transfer pump. In this experiment, 1-hexene, toluene, and heptanal were separated using columns T-01, T-02, and T-03, respectively. The rhodium catalyst was finally collected and reused at the bottom of column T-03. The specific process method is as follows:

[0171] S1: Nitrogen replacement in T-01, T-02, and T-03 systems, with oxygen content <0.5%.

[0172] S2: Component analysis and metal content analysis of the upstream mixture were performed. The components included 14.86% 1-hexene, 55.55% toluene, 0.24% tris(2,4-di-tert-butylphenyl)phosphonite, 0.02% tetrarhodium dodecylcarbonyl, and 29.31% heptanal.

[0173] S3: Put into operation the cooling water of the top heat exchangers of towers T-01, T-02, and T-03.

[0174] S4: Start the top vacuum pumps of T-01, T-02, and T-03, and control the vacuum levels of T-01, T-02, and T-03 to -20kPa, -20kPa, and -90kPa, respectively.

[0175] S5: Start the upstream feed pump of T-01 and control the flow rate to 0.6m³. 3 / h, feed material into T-01.

[0176] S6: T-01 liquid level is set to 50%, hot water is used in the bottom heater of the tower, and the heating rate is controlled at 2℃ / min, gradually rising to 65~97℃.

[0177] S7: As the temperature rises, the light components at the bottom of the tower continuously evaporate and vaporize until the T-01 reflux tank reaches 50% liquid level. Then, the T-01 reflux pump is started to establish circulation and the reflux ratio R=1 is controlled.

[0178] S8: Analyze the top and bottom components of T-01, adjust the operation according to the test results until there are no light components at the bottom of T-01, start the T-01 bottom conveying pump to feed to T-02, and control the flow rate to 0.5m³ / h. 3 / h.

[0179] S9: T-02 establishes a 50% liquid level, uses hot water to raise the temperature, controls the heating rate at 2℃ / min, and targets 75~101℃.

[0180] S10: Set the T-02 reflux tank to 50% liquid level, start the T-02 reflux pump, establish circulation, and control the reflux ratio R=1.

[0181] S11: Analyze the top and bottom components of T-02, adjust the operation according to the analysis results until there are no light components at the bottom of T-02, start the T-02 bottom conveying pump to feed T-03, and control the flow rate to 0.5 m³ / s. 3 / h.

[0182] S12: T-03 establishes a 50% liquid level, uses hot water to raise the temperature, controls the heating rate at 2℃ / min, and targets 80~103℃.

[0183] S13: Set the T-03 reflux tank to 50% liquid level, start the T-03 reflux pump, establish circulation, and control the reflux ratio R=1.

[0184] The composition of the top and bottom of T-03 is detected and analyzed. The operation is adjusted according to the analysis results. The catalyst concentrate at the bottom of T-03 is returned to the upstream to participate in the catalytic reaction or collected externally. The components in the T-03 reflux tank are sent to the downstream process.

[0185] Two control cases were set up in this control group, and the process parameters for each control case are shown in Table 9.

[0186] Test Analysis:

[0187] The components in the top and bottom of each distillation column in Comparative Examples 2-1 to 2-2 were analyzed, and the mass contents of 1-hexene, toluene, and heptanal in the top and bottom components of each distillation column were calculated. The rhodium content was also calculated. Specific test results are shown in Tables 10 and 11.

[0188] Table 9 Operating conditions for each type of distillation column

[0189]

[0190] Table 10. Analysis of Organic Components in Each Stage of Distillation Column (Comparative Examples 2-1 to 2-2)

[0191]

[0192] Table 11 Statistical table of metal recovery in comparison examples 2-1 to 2-2

[0193]

[0194] Analysis of Tables 9-11 shows that the distillation column effectively separates, purifies, and recovers the catalyst from the mixture components. Furthermore, no metal components were detected at the top of the column, indicating that the reflux of the material at the top and the packing material within the distillation column effectively inhibited catalyst loss. The catalyst at the bottom of the column maintained high activity, suggesting that the catalyst recovery effect of the distillation column process is superior to that of the traditional falling film process. However, based on the component analysis in Table 10, as the operating temperature of each column increased, a small amount of the target light components remained at the bottom of the column, indicating that the removal of light components was not as effective as that of the traditional falling film process. Possible reasons include: (1) Due to equipment limitations, the evaporation rate per unit area in the distillation process is lower than that in the falling film process, requiring higher temperatures to separate and purify mixtures with the same components. (2) Because the distillation column contains packing material, the resistance drop when the evaporating components pass through the equipment is greater than that in the falling film process, perhaps requiring a lower vacuum.

[0195] Considering the aforementioned possible reasons, Comparative Example 2 primarily focused on adjusting temperature control. Under the premise that other control conditions remained unchanged, after increasing the temperature of each column by approximately 10-20°C in Comparative Example 2, no target light components were detected at the bottom of columns T-01, T-02, and T-03, achieving the separation and purification target satisfactorily. However, sampling at the bottom of each column revealed a small amount of black insoluble matter, and the catalytic activity of the concentrated catalyst solution showed varying degrees of decline. This was due to uneven heat transfer in the distillation column reboiler, with localized overheating in areas such as the reboiler wall. Since the catalyst is heat-sensitive, prolonged heating at excessively high temperatures degrades its stability, leading to breakage, decomposition, or oxidation, resulting in decreased catalytic activity. Returning the catalyst to the upstream reaction often resulted in unsatisfactory catalytic effects. In summary, while a simple distillation process can achieve efficient separation of multiple components and complete catalyst recovery, the recovered catalyst has poor activity, and the deactivated catalyst has no value for recycling.

[0196] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for separating and recovering noble metal catalysts from multi-component organic mixtures, characterized in that, The multi-component organic mixture contains a noble metal catalyst and a first organic component, a second organic component, and a third organic component with sequentially increasing boiling points; The recovery method includes: performing multi-stage separation on the multi-component organic mixture, wherein each stage of separation includes falling film evaporation separation and distillation separation; separating the first organic component, the second organic component, and the third organic component sequentially from the multi-component organic mixture through the multi-stage separation; and recovering the residue components rich in precious metal catalyst remaining after the multi-stage separation.

2. The separation and recovery method according to claim 1, characterized in that, The multi-level separation is a three-level separation, specifically including: S1. First-stage separation: The multi-component organic mixture is subjected to a first falling film evaporation separation to obtain a first light component and a first heavy component; the first light component is subjected to a first distillation separation to separate the first organic component and the first bottom feed. S2, Second-stage separation: The first heavy component and the first column bottom feed are combined and then subjected to a second falling film evaporation separation to obtain a second light component and a second heavy component; the second light component is subjected to a second distillation separation to separate the second organic component and the second column bottom feed. S3, Third-stage separation: The second heavy component and the second column bottom feed are combined and then subjected to third falling film evaporation separation to obtain a third light component and a third heavy component; the third light component is subjected to third distillation separation to separate the third organic component and the third column bottom feed; S4. Recover the third heavy component and the third tower bottom feed to obtain the precious metal catalyst.

3. The separation and recovery method according to claim 1, characterized in that, The first organic component has a boiling point ≤ 81℃, the second organic component has a boiling point greater than 81℃ and less than 150℃, and the third organic component has a boiling point ≥ 150℃.

4. The separation and recovery method according to claim 2, characterized in that, The first falling film evaporation separation is carried out under a vacuum of -20 to -50 kPa and a temperature of 65 to 75 °C; the first distillation separation is carried out under a vacuum of -20 to -50 kPa. The second falling film evaporation separation is carried out under a vacuum of -20 to -50 kPa and a temperature of 75 to 85 °C; the second distillation separation is carried out under a vacuum of -20 to -50 kPa. The third falling film evaporation separation is carried out under vacuum conditions of -85 to -95 kPa and temperature conditions of 80 to 95 °C; the third distillation separation is carried out under vacuum conditions of -85 to -95 kPa.

5. The separation and recovery method according to claim 1, characterized in that, The material conveying rate in the falling film evaporation separation is 0.3–0.6 m³ / h; and / or, the separation and recovery method is carried out in an environment with an oxygen volume content ≤0.5%.

6. The separation and recovery method according to claim 1, characterized in that, Before performing a multi-stage separation step on the multi-component organic mixture, the multi-component organic mixture is dissolved in an organic solvent with a boiling point higher than that of the third organic component, and the organic solvent does not affect the catalytic reaction of the noble metal catalyst.

7. The separation and recovery method according to claim 6, characterized in that, The organic solvent is selected from N-methylpyrrolidone, glycerol, mineral oil, white oil, liquid paraffin, diphenyl ether, dibutyl phthalate, triglyceride, sulfolane, or diphenyl ether.

8. The separation and recovery method according to claim 1, characterized in that, The first organic component includes one or more of methanol, ethanol, isopropanol, tetrahydrofuran, acetone, n-hexane, cyclohexane, dichloromethane, dichloroethane, butene, and hexene; The second organic component includes one or more of dichloropentane, n-propanol, toluene, xylene, and methylcyclohexane; The third organic component includes one or more of hexachloroethane, N,N-dimethylformamide, dimethyl sulfoxide, ethylene glycol, and glycerol; The noble metal catalyst is selected from elements or compounds containing platinum group metals.

9. A system for separating and recovering noble metal catalysts from multi-component organic mixtures, characterized in that, include: A multi-stage separation and recovery system includes a first separation and recovery system, a second separation and recovery system, and a third separation and recovery system connected in series. Each separation and recovery system is equipped with a falling film evaporator, a separation chamber, a distillation column, and a reflux tank. The lower end of the falling film evaporator is connected to the separation chamber, the upper end of the separation chamber is connected to the bottom of the distillation column, and the top of the distillation column is connected to the reflux tank. A heat supply system is used to provide hot water to the shell side of each falling film evaporator; A vacuum system is used to control the vacuum pressure of the multi-stage separation and recovery system; The feed control system is used to control the feed rate of each falling film evaporator.

10. The separation and recovery system according to claim 9, characterized in that, When the liquid level in the separation chamber of the first and second separation and recovery systems reaches 40% to 50%, the transfer pump is started to transport the material in the separation chamber to the next separation and recovery system.

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