Circulating gas stripping device for organic solvent

Abstract

The utility model belongs to the technical field of petroleum and chemical engineering, and particularly discloses a circulating gas stripping device for an organic solvent. Comprising a heating device, a drying tower, a deoxidizing gas stripping tower, a condenser and a deoxidizing and impurity removing tower, a feeding hole in the bottom of the drying tower is used as a feeding hole of the circulating gas stripping device, and a drying agent is arranged in the drying tower; a first inlet in the side wall of the deoxygenation gas stripping tower is connected with a discharge hole in the top of the drying tower, and a second inlet in the side wall of the deoxygenation gas stripping tower is connected with a first outlet of the heating device. The drying tower and the deoxygenization gas stripping tower are adopted for deoxygenization and water removal of the organic solvent at the temperature of about 30-60 DEG C, the organic solvent can be in close contact with a drying agent or a contact filler or other media in the tower, mass transfer is enhanced, temperature distribution in a reaction system is better controlled, and the reaction efficiency is improved. And high-efficiency drying and deoxidation treatment of materials can be realized under relatively mild conditions.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of petroleum and chemical industry, and more particularly, relates to a circulating gas stripping device for organic solvents. BACKGROUND

[0002] In the context of global energy structure transformation and surging demand for clean energy, the water and oxygen content in solvents in the chemical production industry, especially in the field of polymerization and fine chemical industry, can cause catalyst deactivation, polymer degradation and byproduct generation, affecting product quality. Therefore, reducing water and oxygen content is crucial for improving the quality and consistency of polymer products, and can also reduce side reactions and extend product life. At the same time, controlling water and oxygen content can also prevent polymerization reaction explosions or fires caused by oxidation reactions. In the field of fine chemicals, due to the high requirements for product purity and performance, trace amounts of water and oxygen in solvents can seriously affect the performance of the final product. Dehydration and deoxygenation technology can effectively remove these impurities, ensuring the performance and effectiveness of high-value-added fine chemical products such as pharmaceuticals, pesticides, fragrances, and dyes.

[0003] With the development of dehydration and deoxygenation technology in the chemical industry, gas stripping separation technology for dehydration and deoxygenation is increasingly attracting attention. This technology has the ability to efficiently extract high-purity raw materials, and has a decisive impact on optimizing product quality and performance in the process of polymerization and fine chemical and other chemical production.

[0004] Currently, gas stripping towers mainly use dry stripping and wet stripping methods. For example, patent document CN106715657A discloses an innovative deodorization and cleaning system for light coal tar, aiming to solve the problems existing in the traditional light coal tar process, such as high sulfur and nitrogen content, dark color, and high impurity content. The system uses a series of specific processing units, including a steam stripping tank, a static separation tank, a static dehydration tank, a desulfurization resin tank, a desulfurization catalyst tank, and a solid treatment agent tank, to achieve deep purification of coal tar. Finally, the color and odor of the treated light coal tar are significantly improved, and the content of sulfur, nitrogen, and other components is reduced to below 50 ppm, meeting the quality requirements as a reforming device raw material. The system includes multiple processing units and pipelines, increasing the complexity of operation and the skill requirements of operators.

[0005] To avoid the moisture oxygen of raw materials brought by wet method, patent document CN221491481U discloses a polymer polyol (POP) single removal device. The process device adopts material-driven disc impeller distributor to ensure the uniform distribution of materials in the cylinder, avoiding the problem of equipment blockage. At the same time, inert gas (such as N2) is used to promote the evaporation and removal of monomers, instead of relying on steam or liquid in wet gas stripping, realizing the environmental protection effect of no wastewater generation and significantly reducing energy consumption. Patent CN219423761U proposes an innovative nitrogen stripping tower to improve energy efficiency and reduce production costs in oil processing. The stripping tower uses nitrogen as a stripping agent, which is heated to high temperature by a heating device and then sent into the tower body to contact with the raw oil in countercurrent, realizing the effective removal of light components. This process significantly increases the initial temperature of nitrogen, reduces the energy consumption of the heater, and realizes the efficient use of energy. However, due to the design of the heat dissipation fins and the heat dissipation water tank, the maintenance cost and cleaning difficulty may be increased. Patent document CN116836719A proposes a new type of non-condensable gas circulating stripping device system and its stripping separation method, mainly used in the oil separation process in the field of petroleum and petrochemical technology. The system consists of a non-condensable gas stripping unit and a membrane separation unit, including a stripping tower, an air cooler, a tower top reflux tank, a membrane separation device, a booster device and a heat exchange device. In the experiment, the tower top and bottom temperatures are in the range of 130~175℃, the pressure is 0.6~0.65MPa, and the non-condensable gas is circulated in the system. The gas phase product is separated by the membrane separation device to obtain light components and non-condensable gas, and is pressurized again for stripping, realizing no wastewater discharge, especially the energy consumption of the system is only 11% of the comparative example. But the membrane separation device used in this stripping device involves high investment cost, which will affect its industrialization process. Practical new type content

[0006] In view of the defects of the prior art, the purpose of the present application is to improve the existing non-condensable gas circulating stripping device, thereby reducing the production cost and improving the application range of the circulating stripping device.

[0007] To achieve the above purpose, the present application provides a circulating stripping device for organic solvents, which comprises a heating device, a drying tower, a deoxygenation stripping tower, a condenser and a deoxygenation and impurity removal tower; the heating device is used to heat the non-condensable gas to 30℃~60℃;

[0008] The bottom feed inlet of the drying tower serves as the feed inlet of the circulating stripping device for feeding the organic solvent to be separated, and the inside of the drying tower is provided with a drying agent;

[0009] The first inlet of the side wall of the deoxygen stripping tower is connected to the top discharge port of the drying tower, and the second inlet of the side wall is connected to the first outlet of the heating device for introducing non-condensable gas; the first inlet of the side wall of the deoxygen stripping tower is located above the second inlet of the side wall, and a contact filler is provided between the second inlet of the side wall and the first inlet of the side wall; the bottom discharge port of the deoxygen stripping tower is used to guide out the organic solvent after gas stripping;

[0010] The inlet of the condenser is connected to the top gas outlet of the deoxygen stripping tower, and the third inlet at the top of the deoxygen stripping tower is connected to the discharge port of the condenser; the condenser is used to cool the non-condensable gas exchanged with the organic solvent to room temperature, and transport the liquid phase back to the deoxygen stripping tower, and transport the gas phase to the deoxygenation and impurity removal tower;

[0011] The bottom inlet of the deoxidation and impurity removal tower is connected to the top air outlet of the condenser, and a deoxidizer is provided inside the deoxidation and impurity removal tower;

[0012] The first inlet of the heating device is connected to the top outlet of the deoxidation and impurity removal tower, and the second inlet serves as the air inlet of the circulating gas stripping device.

[0013] Preferably, at the bottom feed port of the drying tower, the flow rate of the organic solvent is 200 mL / min to 300 mL / min.

[0014] Preferably, the flow rate of the non-condensable gas at the first inlet of the side wall of the deoxygenating stripping tower is 0.5 to 15 times the flow rate of the organic solvent.

[0015] Preferably, the circulating gas stripping device further comprises a first centrifugal pump and a collecting device sequentially connected to the bottom discharge port of the deoxygenating stripping tower;

[0016] The first centrifugal pump is used to promote the organic solvent after gas stripping to flow towards the collection device;

[0017] The collecting device is used to collect the organic solvent after gas stripping.

[0018] As a further preference, a heat exchange device is provided at the contact point of the pipeline between the deoxygenation stripping tower and the collecting device, and the pipeline between the deoxygenation and impurity removal tower and the heating device, for reducing the temperature of the organic solvent entering the collecting device and increasing the temperature of the non-condensable gas entering the heating device.

[0019] Preferably, a second centrifugal pump is provided between the third inlet at the top of the deoxygenating stripping tower and the discharge port of the condenser, and the second centrifugal pump is used to facilitate the flow of part of the organic solvent separated by the condenser back to the deoxygenating stripping tower.

[0020] Preferably, a booster device is further arranged between the top outlet of the deoxygenation and impurity removal tower and the first inlet of the heating device; the booster device is used to pressurize the non-condensable gas output from the deoxygenation and impurity removal tower to 0.1 MPa ~ 1 MPa.

[0021] Preferably, the desiccant is silica gel desiccant, activated alumina desiccant or calcium-aluminum-silicate molecular sieve desiccant, the contact filler is a Pall ring, a Raschig ring, a ladder ring, a Helix ring, a Taylor ring or a Snowflake ring, and the deoxidizer is activated carbon deoxidizer, metal oxide deoxidizer or nickel catalyst deoxidizer.

[0022] Preferably, the non-condensable gas is one or more of N2, H2, CO2 or CH4.

[0023] Preferably, a first on-off valve is arranged between the side wall second inlet of the deoxygenation and stripping tower and the first outlet of the heating device, a second on-off valve is arranged between the top outlet of the deoxygenation and impurity removal tower and the first inlet of the heating device, a third on-off valve is arranged at the top gas inlet of the drying tower and communicated with the second outlet of the heating device, a fourth on-off valve is arranged at a pipeline communicated between the top gas inlet of the deoxygenation and impurity removal tower and the third outlet of the heating device, and a fifth on-off valve is arranged between the discharge port of the drying tower and the side wall first inlet of the deoxygenation and stripping tower; the on-off valves are not only used to close the channel of the non-condensable gas to other devices when the material to be separated is separated, but also used to introduce a regenerating gas and close the channel of the drying tower or the deoxygenation and impurity removal tower to other devices when the desiccant in the drying tower or the deoxidizer in the deoxygenation and impurity removal tower needs to be regenerated.

[0024] As a further preferred, the upper limit of the working temperature of the heating device is 110℃ ~ 210℃.

[0025] Another purpose of the present application is to provide the above-mentioned circulating stripping device in the application of the circulating stripping of the organic solvent.

[0026] Overall, compared with the prior art, the above technical solutions conceived by the present application have the following technical advantages:

[0027] 1. This application utilizes a drying tower and a deoxygenation stripping tower to deoxygenate and dehydrate the organic solvent. This process can be performed at temperatures of approximately 30°C to 60°C, a 50°C to 100°C reduction compared to existing technologies, resulting in lower energy consumption. Furthermore, the organic solvent can be in close contact with media such as desiccants or contact fillers within the tower, enhancing mass transfer and better controlling the temperature distribution within the reaction system. This allows for efficient drying and deoxygenation of the material under relatively mild conditions.

[0028] 2. This application utilizes a condenser to cool the non-condensable gas after the exchange with the organic solvent to room temperature, and transports the liquid phase back to the deoxygenation stripping tower, thereby reducing the difficulty of subsequent treatment of the non-condensable gas;

[0029] 3. A heat exchanger is preferably used to exchange heat between the organic solvent and the non-condenser. The non-condensable gas after deoxidation can continue to be introduced into the system for circulation under a certain heating condition, thereby saving energy costs and realizing the recycling of raw materials.

[0030] 4. Preferably, the desiccant and deoxidizer can be regenerated by using several switch valves without disassembling the device, which is simple to install, low cost and has good repeatability.

[0031] 5. It has been verified that the water and oxygen contents of the organic solvent after treatment by the device of the present application are less than 1 ppm, which significantly reduces the moisture and oxygen content in the organic solvent; the treated material can be used in environments with water and oxygen content control index requirements, such as for polymerization reaction processes; this application achieves an optimal balance between cost-effectiveness and process efficiency, providing an innovative solution for industrial production; it can stabilize the reaction center and simplify the downstream separation process, providing a cost-effective, efficient and environmentally friendly solution for the chemical industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a simplified structural diagram of the circulating gas stripping device of this application;

[0033] Figure 2 This is a schematic diagram of the structure of Example 1 of the present application;

[0034] Figure 3 This is a schematic structural diagram of Comparative Example 1 of this application;

[0035] In all the drawings, the same reference numerals are used to represent the same elements or structures, wherein: 1-heating device, 2-drying tower, 3-deoxygen stripping tower, 4-condenser, 5-deoxygenation and impurity removal tower, 61-first centrifugal pump, 62-second centrifugal pump, 7-heat exchanger, 8-collecting device, 9-boosting device, 11-first switch valve, 12-second switch valve, 13-third switch valve, 14-fourth switch valve, 15-fifth switch valve. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the present application.

[0037] In the description of the present application, it should be understood that the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0038] In addition, throughout the specification, the reference to "one embodiment"; "one embodiment", "one example" or similar language means that the specific features, structures or characteristics described in connection with the embodiment are included in at least one embodiment of the present application. Therefore, the appearance of the phrase "in one embodiment" and similar language throughout the specification may, but does not necessarily, all refer to the same embodiment.

[0039] Figure 1 is a simplified structure schematic diagram of the circulating gas stripping device of the present application, wherein the red channel schematically shows the main component passing through the inside, which is non-condensable gas, the black channel schematically shows the main component passing through the inside, which is organic solvent, and the channels with the same main component but crossing each other are represented by solid lines and dashed lines respectively; the circulating gas stripping device can be used for organic solvents such as alkane solvents (hexane, heptane), cycloalkane solvents (cyclohexane), aromatic solvents (toluene) and the like; the circulating gas stripping device includes a heating device 1, a drying tower 2, a deoxygenation stripping tower 3, a condenser 4, a first centrifugal pump 61, a collection device 8 and a deoxygenation and impurity removal tower 5 and the like;

[0040] The bottom feed inlet of the drying tower 2 serves as the feed inlet of the circulating gas stripping device, and is used to pass in the organic solvent to be separated at a flow rate of 200 mL / min to 300 mL / min, and the inside of the drying tower 2 is provided with a drying agent; in some embodiments, the drying agent is a silica gel drying agent, an activated alumina drying agent or a calcium alumino-silicate molecular sieve drying agent;

[0041] The side wall first inlet of the deoxygenation stripping tower 3 is connected to the top discharge outlet of the drying tower 2, and the side wall second inlet is connected to the first outlet of the heating device 1, and is used to pass in the non-condensable gas heated to 30°C to 60°C by the heating device 1; the non-condensable gas is one or more of N2, H2, CO2 or CH4;

[0042] The side wall second inlet of the deoxidizing gas stripping tower 3 is located above the side wall first inlet, and a contact packing is arranged between the side wall second inlet and the side wall first inlet; the contact packing is a Pall ring, a Raschig ring, a ladder ring, a Hel ring, a Taylor ring or a snowflake ring; the bottom discharge port of the deoxidizing gas stripping tower 3 is connected with a first centrifugal pump 61 and a collecting device 8 in sequence, and under the action of the first centrifugal pump 61, the stripped organic solvent is collected into the collecting device 8;

[0043] The inlet of the condenser 4 is connected with the top gas outlet of the deoxidizing gas stripping tower 3, the discharge port of the condenser 4 is connected with the top third inlet of the deoxidizing gas stripping tower 3, and the top gas outlet is connected with the bottom inlet of the deoxidizing impurity removal tower 5; after the condenser 4, the non-condensed gas is cooled to normal temperature, and part of the organic solvent components are reflowed to the deoxidizing gas stripping tower 3 from the discharge port, and the non-condensed gas enters the deoxidizing impurity removal tower 5 to be deoxidized; the deoxidizing impurity removal tower 5 is provided with a deoxidizing agent, such as an activated carbon deoxidizing agent, a metal oxide deoxidizing agent or a nickel catalyst deoxidizing agent; the non-condensed gas reenters the heating device 1 after being deoxidized in the deoxidizing impurity removal tower 5; the heating device is also provided with a second inlet for supplementing the non-condensed gas from the outside, so that the flow rate of the non-condensed gas in the deoxidizing gas stripping tower 3 is 0.5 times to 15 times (by volume) of the flow rate of the organic solvent; in some embodiments, the second inlet can also pass the first regeneration gas and the second regeneration gas for regeneration.

[0044] In one embodiment, a second centrifugal pump 62 is further arranged between the top third inlet of the deoxidizing gas stripping tower 3 and the discharge port of the condenser 4, and the second centrifugal pump 62 is used to promote the flow of part of the organic solvent separated by the condenser 4 back to the deoxidizing gas stripping tower 3; in another embodiment, a heat exchange device 7 is further arranged at the contact position of the pipeline between the deoxidizing gas stripping tower 3 and the collecting device 8 and the pipeline between the deoxidizing impurity removal tower 5 and the heating device 1, so as to reduce the temperature of the organic solvent entering the collecting device 8 and increase the temperature of the non-condensed gas entering the heating device 1; in another embodiment, a booster device 9 is further arranged between the top outlet of the deoxidizing impurity removal tower 5 and the first inlet of the heating device 1; the booster device is used to pressurize the non-condensed gas output from the deoxidizing impurity removal tower 5 to 0.1 MPa to 1 MPa.

[0045] In one embodiment, in order to achieve the regeneration of the desiccant inside the drying tower 2 and the deoxidizer inside the deoxidation and impurity removal tower 5, a first switch valve 11 is provided between the second inlet of the side wall of the deoxidation and impurity removal tower 3 and the first outlet of the heating device 1, and a second switch valve 12 is provided between the top outlet of the deoxidation and impurity removal tower 5 and the first inlet of the heating device 1. The drying tower 2 and the deoxidation and impurity removal tower 5 are also provided with a top air inlet, a communicating pipe is provided between the top air inlet of the drying tower 2 and the second outlet of the heating device 1, and a third switch valve 13 is provided on the pipe, a communicating pipe is provided between the top air inlet of the deoxidation and impurity removal tower 5 and the third outlet of the heating device, and a fourth switch valve 14 is provided on the pipe, and a fifth switch valve 15 is provided between the discharge port of the drying tower 2 and the first inlet of the side wall of the deoxidation and impurity removal tower 3. Figure 2 As shown; the configuration of on-off valves is not limited to the five described above; the attached figure only shows valves of relatively important shapes for the regeneration of the desiccant and deoxidizer. When the desiccant in drying tower 2 needs to be regenerated, the third on-off valve 13 is opened and the other on-off valves are closed, allowing the first regeneration gas to be discharged from the bottom feed port through drying tower 2. When the deoxidizer in deoxidation and impurity removal tower 5 needs to be regenerated, the fourth on-off valve 14 is opened and the other on-off valves are closed (the fifth on-off valve 15 may not be closed), allowing the second regeneration gas to be discharged from the bottom inlet through deoxidation and impurity removal tower 5. The first and second regeneration gases can be one or more of N2, H2, CO2, or CH4, with a temperature of 110-210°C and a pressure of 0.1-0.5 MPa. Therefore, to balance the needs of circulating gas and regeneration in the stripping device, the upper operating temperature limit of the heating device 1 is preferably 110-210°C. The first regeneration gas is preferably N2, and the second regeneration gas is preferably a mixed gas with a volume ratio of 5% H2 / 95% N2. The regeneration time is preferably 24-72 hours.

[0046] Taking the circulating gas stripping device with the above-mentioned switching valve as an example, the working process of the gas stripping is as follows:

[0047] S1. Open the first switch valve 11, the second switch valve 12, close the third switch valve 13, the fourth switch valve 14; to the drying tower 2 at a flow rate of 200 mL / min ~ 300 mL / min, continuously introduce room temperature organic solvent; the pressure of the organic solvent needs to ensure that it can flow out from the top discharge port;

[0048] S2. Subsequently, the dried organic solvent is flowed into the deoxygenation stripping tower 3 at a flow rate of 200 mL / min to 300 mL / min, while the non-condensable gas heated to 30°C to 60°C in the heating device 1 is introduced. Since the material inlet is above the gas inlet, the heated non-condensable gas meets the liquid organic solvent in the contact filler of the deoxygenation stripping tower 3 and deoxygenates the organic solvent. The deoxygenated organic solvent is recovered from the bottom outlet into the recovery tank 8 with the assistance of the first centrifugal pump 61.

[0049] S3. The non-condensable gas flowing out of the top outlet of the deoxygenation stripping tower 3 enters the gas inlet of the condenser 4 and is further cooled to room temperature. Due to the mixed steam containing a portion of the organic solvent, the cooled liquid component is mainly the organic solvent, which is flowed back to the top third inlet of the deoxygenation stripping tower 3 through the outlet of the condenser 4.

[0050] S4. The gas component mainly composed of non-condensable gas flowing out of the condenser 4 first enters the deoxygenation and impurity removal tower 5, and is deoxygenated and impurity-removed by the deoxygenating agent in the tower, and then reenters the heating device 1 for heating. Since there is no non-condensable gas in the initial state of the circulating stripping device, and the non-condensable gas is also lost to a certain extent during the circulating stripping process, an external gas source at the second inlet of the heating device 1 is needed to supplement the non-condensable gas to ensure that the flow rate of the non-condensable gas remains stable.

[0051] The working process of the same circulating stripping device when the desiccant is regenerated is as follows:

[0052] The third switch valve 13 is opened, and the first switch valve 11, the second switch valve 12, and the fourth switch valve 14 are closed. The second inlet of the heating device 1 is connected to the gas source of the first regeneration gas, which is heated to 110°C to 210°C, and then introduced into the drying tower 2. The gas passes through the desiccant that needs to be regenerated in the drying tower 2 and flows out from the bottom inlet of the drying tower 2.

[0053] The working process of the same circulating stripping device when the deoxygenating agent is regenerated is as follows:

[0054] The fourth switch valve 14 is opened, and the first switch valve 11, the second switch valve 12, and the third switch valve 13 are closed. The second inlet of the heating device 1 is connected to the gas source of the second regeneration gas, which is heated to 110°C to 210°C, and then introduced into the deoxygenation and impurity removal tower from top to bottom through the second inlet at the top of the tower, and finally discharged from the bottom inlet of the deoxygenation and impurity removal tower 5, thereby completing the regeneration of the deoxygenating agent.

[0055] The following is an example.

[0056] Example 1

[0057] The structure of the non-condensable gas circulating stripping device of this example is as follows: Figure 2As shown, mainly includes heating device 1, drying tower 2, deoxidizing gas extraction tower 3, first centrifugal pump 61, heat exchanger 7, recovery tank 8, condenser 4, second centrifugal pump 62, booster device 9 and deoxidizing and impurity removing tower 5 and so on;

[0058] Wherein, the inside of the drying tower 2 is provided with 5A type calcium-aluminum-silicate desiccant (the model of this embodiment is 5A-DG-K), the bottom feed inlet of the drying tower 2 is connected with the input pipeline of external material, for passing in the material to be separated at normal temperature, the material in this embodiment is n-heptane, which is liquid at normal temperature; the top gas inlet of the drying tower 2 is used for passing to the first regeneration gas when the internal desiccant is regenerated.

[0059] The side wall first inlet of the deoxidizing gas extraction tower 3 is connected with the top discharge outlet of the drying tower 2, for passing in the dried n-heptane, the side wall second inlet is connected with the first outlet of the heating device 1, for passing in the heated N2; the side wall first inlet is located above the side wall second inlet, the deoxidizing gas extraction tower 3 is provided with scattered stainless steel Pall rings (stainless steel model S304) with a diameter of about 25mm between the side wall first inlet and the side wall second inlet;

[0060] The feed inlet of the recovery tank 8 is connected with the bottom discharge outlet of the deoxidizing gas extraction tower 3, for collecting the gas-extracted material, and the first centrifugal pump 61 is further provided between the recovery tank 8 and the deoxidizing gas extraction tower 3, for accelerating the pumping of the material in the deoxidizing gas extraction tower 3 into the recovery tank 8;

[0061] The second centrifugal pump 62 is connected between the top gas outlet of the deoxidizing gas extraction tower 3 and the inlet of the condenser 4, and the discharge outlet of the condenser 4 is connected with the top third inlet of the deoxidizing gas extraction tower 3;

[0062] The deoxidizing and impurity removing tower 5 is provided with copper-based metal oxide deoxidizing and impurity removing agent (model 513-1T); the bottom inlet of the deoxidizing and impurity removing tower 5 is connected with the top gas outlet of the condenser 4; the top outlet is connected with the inlet of the booster device 9; the outlet of the booster device 9 is connected with the first inlet of the heating device 1; the top of the deoxidizing and impurity removing tower 5 is further provided with a top gas inlet, for passing in the second regeneration gas when the internal deoxidizing agent is regenerated; the second inlet of the heating device 1 is connected with an external gas source, for supplementing N2 or regeneration gas;

[0063] The heat exchanger 7 is further provided between the pipeline between the deoxidizing gas extraction tower 3 and the recovery tank 8, and the pipeline between the outlet of the booster device 9 and the heating device 1, for reducing the temperature of n-heptane in the former pipeline and increasing the temperature of N2 in the latter pipeline;

[0064] A first switch valve 11 is arranged between the first inlet of the side wall of the deoxidizing stripping tower 3 and the top outlet of the drying tower 2, a second switch valve 12 is arranged between the first inlet of the heating device 1 and the outlet of the pressurizing device 9, a third switch valve 13 is arranged between the top inlet of the drying tower 2 and the second outlet of the heating device 1, a fourth switch valve 14 is arranged between the top inlet of the deoxidizing and impurity-removing tower 5 and the third outlet of the heating device 1, and a fifth switch valve 15 is arranged between the outlet of the drying tower 2 and the first inlet of the side wall of the deoxidizing stripping tower 3. The third switch valve 13 and the fourth switch valve 14 are usually opened only when the drying agent in the drying tower 2 or the deoxidizing agent in the deoxidizing and impurity-removing tower 5 is regenerated.

[0065] The working process of stripping n-heptane material using the non-condensable gas circulating stripping device of the embodiment is as follows:

[0066] S1. The first switch valve 11, the second switch valve 12 and the fifth switch valve 15 are opened, and the third switch valve 13 and the fourth switch valve 14 are closed. The room-temperature n-heptane is continuously fed into the drying tower 2 at a flow rate of 200 mL / min to 300 mL / min. The pressure of the n-heptane needs to be ensured to flow out from the top outlet;

[0067] S2. Subsequently, the dried n-heptane flows into the deoxidizing stripping tower 3 at a flow rate of 200 mL / min to 300 mL / min, and the heated N2 at 30°C to 60°C and at a pressure of 0.85 MPa is fed in at a gas-liquid ratio of 0.5 (i.e., the volume of the fed-in gas-phase N2 is about 0.5 times that of the n-heptane). Since the material inlet is above the gas inlet, the heated N2 meets the liquid material in the contact filler of the deoxidizing stripping tower 3 and deoxidizes the material. The deoxidized material flows out from the bottom outlet and is recovered into the recovery tank 8 with the assistance of the first centrifugal pump 61.

[0068] S3. The N2 flowing out from the top gas outlet of the deoxidizing stripping tower 3 enters the inlet of the condenser 4 under the action of the second centrifugal pump 62 and is further cooled to room temperature. Since a part of the material vapor is mixed in the middle, a part of the n-heptane material is separated after cooling. The n-heptane material is fed back into the top third inlet of the deoxidizing stripping tower 3 through the outlet of the condenser 4.

[0069] S4. The N2-based gas component flowing out of the condenser 4 first enters the deoxidizing and impurity removing tower 5, is deoxidized and impurity removed by the deoxidizer inside the deoxidizing and impurity removing tower 5, is pressurized to a pressure of about 0.85 MPa by the pressure increasing device 9, and then is heated in the heating device 1 again. Since there is no N2 in the initial state of the circulating gas stripping device, and the N2 is also lost to a certain extent during the circulating gas stripping process, the N2 needs to be supplemented from the external gas source at the second inlet of the heating device 1, as long as the gas and liquid phase volume ratio entering the deoxidizing and impurity removing tower 5 is maintained at 1:2. The heater 1 can play a heating role under different temperature conditions during the material circulating gas stripping and the regeneration of the drying agent and the deoxidizer.

[0070] Through the above-mentioned circulating gas stripping process, the n-heptane material collected in the recovery tank 8 is detected, and the water content is reduced from 40 ppm to 0.70 ppm, and the oxygen content is reduced from 40 ppm to 0.87 ppm compared with before the n-heptane material is introduced into the drying tower 2.

[0071] Example 2

[0072] After the non-condensable gas circulating gas stripping device in Example 1 is used for more than 1000 hours, the drying agent and the deoxidizer are regenerated.

[0073] Step one: regeneration of the drying agent

[0074] The third switch valve 13 is opened, and the fifth switch valve 15, the first switch valve 11, the second switch valve 12 and the fourth switch valve 14 are closed; N2 heated to 150℃ by the heating device 1 is introduced into the drying tower 2 at a flow rate of 100 Nm³ / h, and the N2 passes through the drying agent that needs to be regenerated and then flows out from the bottom inlet of the drying tower 2. After 24 hours of continuous introduction of N2, the regeneration of the drying agent is completed.

[0075] Step two: regeneration of the deoxidizer

[0076] The fourth switch valve 14 is opened, and the first switch valve 11, the second switch valve 12 and the third switch valve 13 are closed; the second inlet of the heating device 1 is connected to the gas source of the second regeneration gas (the second regeneration gas includes 5% H2 and 95% N2 in this example), and the second regeneration gas is heated to 150℃; the mixed gas enters from the top gas inlet of the deoxidizing and impurity removing tower and is finally discharged from the bottom inlet of the deoxidizing and impurity removing tower 5; during the process, the operating pressure is maintained at 0.24 MPa, and the flow rate of the mixed gas is controlled at 100 Nm³ / h. After 24 hours of continuous introduction of the second regeneration gas, the regeneration of the drying agent is completed.

[0077] Step three: circulating gas stripping

[0078] When both the drying agent and the deoxidizer are regenerated, repeat the whole process of Example 1, and the results of the circulating stripping are shown in Table 1.

[0079] Example 3

[0080] Toluene, an aromatic compound, also plays an important role in the polymerization reaction. Toluene and the like serve as a solvent in the polymerization reaction, help to dissolve the raw material and the catalyst, and adjust the viscosity and temperature of the reaction system, thus providing a stable site for the polymerization reaction.

[0081] Example 3 is repeated with the same steps as in Example 1, except that toluene is used instead of n-heptane as the material in Example 1, and the results of the circulating stripping are shown in Table 1.

[0082] Example 4

[0083] Example 3 is repeated with the same steps as described above, except that the gas-liquid ratio in step S2 is set to 1 (the flow rate of the material is unchanged, and the flow rate of the gas is changed), and the results of the circulating stripping are shown in Table 1.

[0084] Example 5

[0085] Example 3 is repeated with the same steps as described above, except that the gas-liquid ratio in step S2 is set to 3 (the flow rate of the material is unchanged, and the flow rate of the gas is changed), and the results of the circulating stripping are shown in Table 1.

[0086] Example 6

[0087] Example 3 is repeated with the same steps as described above, except that the gas-liquid ratio in step S2 is set to 5 (the flow rate of the material is unchanged, and the flow rate of the gas is changed), and the results of the circulating stripping are shown in Table 1.

[0088] Example 7

[0089] Example 3 is repeated with the same steps as described above, except that the gas-liquid ratio in step S2 is set to 10 (the flow rate of the material is unchanged, and the flow rate of the gas is changed), and the results of the circulating stripping are shown in Table 1.

[0090] Example 8

[0091] Example 3 is repeated with the same steps as described above, except that the gas-liquid ratio in step S2 is set to 15 (the flow rate of the material is unchanged, and the flow rate of the gas is changed), and the results of the circulating stripping are shown in Table 1.

[0092] Example 9

[0093] Example 1 is repeated with the same steps as described above, except that the gas-liquid ratio in step S2 is set to 1 (the flow rate of the material is unchanged, and the flow rate of the gas is changed), and the results of the circulating stripping are shown in Table 1.

[0094] Example 10

[0095] Example 1 was repeated with the same steps, except that the gas-liquid ratio of step S2 was set to 3 (the flow rate of the material was unchanged, and the flow rate of the gas was changed), and the results of the circulating stripping are shown in Table 1.

[0096] Example 11

[0097] Example 3 was repeated with the same steps, except that the stainless steel Pall ring (stainless steel type S304) with a diameter of about 25 mm was arranged in the structured packing in the portion of the deoxygenation stripping column 3 between the first side wall inlet and the second side wall inlet, and the results of the circulating stripping are shown in Table 1.

[0098] Comparative Example 1

[0099] Example 3 was repeated with the same steps, except that the deoxygenation stripping column 3 was not filled with packing, and the results of the circulating stripping are shown in Table 1. Figure 3

[0100] Comparative Example 2

[0101] Example 1 was repeated with the same steps, except that no drying agent was arranged in the drying column 2, and the results of the circulating stripping are shown in Table 1.

[0102] Comparative Example 3

[0103] Example 3 was repeated with the same steps, except that no drying agent was arranged in the drying column 2, and the results of the circulating stripping are shown in Table 1.

[0104] Comparative Example 4

[0105] Example 1 was repeated with the same steps, except that the deoxygenation stripping column 3 was not filled with packing, and in the step S1, the first on-off valve 11 remained closed during the reaction stage, and in the step S2, the non-condensable gas was not introduced into the deoxygenation stripping column 3, but the material to be separated was introduced into the deoxygenation stripping column 3 after being dried by the drying column 1, and as shown in Table 1, the material entered the column from the first side wall inlet and flowed downward from the column bottom to the recovery tank 8, without mass transfer and heat exchange processes with the non-condensable gas. Figure 3

[0106] Comparative Example 5

[0107] Comparative Example 4 was repeated with the same steps, except that toluene was used instead of n-heptane as the material in Comparative Example 4.

[0108] Comparative Example 6

[0109] ​​Example 1 was repeated with the same steps, except that the deoxygenation stripping column 3 was not packed, and the drying column 2 was not provided with a drying agent; meanwhile, the first switch valve 11 was kept closed in step S1, and in step S2, as shown in FIG. 2, the material flowed from top to bottom in the deoxygenation stripping column 3, flowed through the column bottom to the recovery tank 8 for collection, and did not perform a mass transfer and heat exchange process with the non-condensable gas. Figure 3 The deoxygenation stripping column 3 was not packed, and the drying column 2 was not provided with a drying agent; meanwhile, the first switch valve 11 was kept closed in step S1, and in step S2, as shown in FIG. 2, the material flowed from top to bottom in the deoxygenation stripping column 3, flowed through the column bottom to the recovery tank 8 for collection, and did not perform a mass transfer and heat exchange process with the non-condensable gas.

[0110] Comparative Example 7

[0111] Comparative Example 6 was repeated with the same steps, except that toluene was used to replace n-heptane in Comparative Example 6 as the material.

[0112] Experimental results verification

[0113] The reaction conditions and reaction results of the different solvents stripped by the non-condensable gas in the above examples and comparative examples are shown in Table 1. The water and oxygen contents of the n-heptane solvent before stripping were about 40 ppm; the water content of the toluene solvent before stripping was about 40 ppm, and the oxygen content was about 15 ppm.

[0114] Table 1: Reaction conditions and water and oxygen content measurements after stripping of different solvents by non-condensable gas

[0115]

[0116] In the examples and comparative examples of the present application, we respectively applied the circulation stripping method to n-heptane with a boiling point below 100°C and toluene with a boiling point above 100°C. As can be seen from Table 1, by using the drying column, we can significantly reduce the water content in these solvents from 40 ppm to below 1 ppm, meeting the strict standards of the polymerization reaction process.

[0117] As can be seen from the toluene stripping experimental data, when the gas-liquid ratio is 0.5, the oxygen content in the deoxygenation stripping column can be reduced from 15 ppm to 10 ppm without using packing, and when the deoxygenation stripping column is respectively introduced with regular packing and random packing, the oxygen content can be further reduced to 0.81 ppm and 0.89 ppm. Based on cost-effectiveness considerations, the random packing has a higher cost performance. In particular, for n-heptane with a boiling point below 100°C, the stripping process using random packing can further reduce the oxygen content to 0.87 ppm. At the same time, after comparing and analyzing the water and oxygen content changes of the material only subjected to drying treatment and only subjected to stripping treatment, we found that the combined use of the drying column and the stripping column significantly improves the efficiency of drying and dehydrating and stripping and deoxygenating, thereby improving the overall efficiency of the material separation and purification.

[0118] In addition, the influence of gas-liquid ratio on the stripping effect was also systematically analyzed. The experimental data revealed that with the increase of gas-liquid ratio, the oxygen content after stripping continued to decrease, but the decreasing amplitude tended to slow down. This finding is crucial for optimizing the process parameters of stripping, which helps to maximize the cost-effectiveness while ensuring the stripping effect.

[0119] Meanwhile, the effect of Example 2 demonstrates that the regeneration method of molecular sieve adsorbent proposed in the present application is not only effective, but also can maintain long-term cyclic use, which is of great significance for improving the economic efficiency and sustainability of the process.

[0120] Those skilled in the art will readily understand that the above description is only preferred embodiments of the present application, and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An organic solvent recycling stripping apparatus characterized by comprising: The heating device, the drying tower, the deoxidizing stripping tower, the condenser and the deoxidizing and impurity-removing tower are included. The bottom inlet of the drying tower is used as the inlet of the circulating stripping device, and the drying agent is arranged in the drying tower. The first side wall inlet of the deoxidizing stripping tower is connected with the top outlet of the drying tower, and the second side wall inlet is connected with the first outlet of the heating device. The inlet of the condenser is connected with the top gas outlet of the deoxidizing stripping tower, and the third top inlet of the deoxidizing stripping tower is connected with the outlet of the condenser. The bottom inlet of the deoxidizing and impurity-removing tower is connected with the top gas outlet of the condenser, and the deoxidizing agent is arranged in the deoxidizing and impurity-removing tower. The first inlet of the heating device is connected with the top outlet of the deoxidizing and impurity-removing tower, and the second inlet is used as the gas inlet of the circulating stripping device.

2. The circulating gas stripping device according to claim 1, characterized in that A first centrifugal pump connected with the bottom outlet of the deoxidizing stripping tower and a collecting device are further included.

3. A circulating gas extraction device as claimed in claim 2, characterised in that, Heat exchange devices are arranged at the contact positions of the pipelines between the deoxidizing stripping tower and the collecting device and between the deoxidizing and impurity-removing tower and the heating device.

4. The circulating gas extraction device of claim 1, wherein, A second centrifugal pump is further arranged between the third top inlet of the deoxidizing stripping tower and the outlet of the condenser.

5. The circulating gas extraction device of claim 1, wherein, A booster device is further arranged between the top outlet of the deoxidizing and impurity-removing tower and the first inlet of the heating device.

6. The circulating gas extraction device of claim 1, wherein, The drying agent is silica gel drying agent, active alumina drying agent or calcium-aluminum-silicate molecular sieve drying agent.

7. The circulating gas extraction device of claim 1, wherein, The contact packing is Pall ring, Rasi ring, ladder ring, Hale ring, Taylor ring or snowflake ring.

8. The circulating gas extraction device of claim 1, wherein, The deoxidizing agent is active carbon deoxidizing agent, metal oxide deoxidizing agent or nickel catalyst deoxidizing agent.

9. The circulating gas extraction device of claim 1, wherein, A first switch valve is arranged between the second side wall inlet of the deoxidizing stripping tower and the first outlet of the heating device, a second switch valve is arranged between the top outlet of the deoxidizing and impurity-removing tower and the first inlet of the heating device, a pipeline connected with the second outlet of the heating device is arranged between the top gas inlet of the drying tower and the second outlet of the heating device, and a third switch valve is arranged on the pipeline, a pipeline connected with the third outlet of the heating device is arranged between the top gas inlet of the deoxidizing and impurity-removing tower and the third outlet of the heating device, and a fourth switch valve is arranged on the pipeline, and a fifth switch valve is arranged between the outlet of the drying tower and the first side wall inlet of the deoxidizing stripping tower.

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