A low energy n-butyraldehyde separation system

Abstract

This invention provides a low-energy-consumption isobutyraldehyde separation system, comprising an atmospheric distillation column and a pressurized distillation column connected by a thermally coupled pipeline. This invention utilizes thermal coupling technology to use the steam generated in the pressurized distillation column as a heat source for the atmospheric distillation column, significantly reducing energy consumption. Furthermore, the optimized internal structure and distributor design improve separation efficiency and reduce equipment investment and operating costs. Compared with existing technologies, this invention represents a significant advancement in energy saving, separation efficiency, and operational stability, making it suitable for large-scale industrial production.

Description

Technical Field

[0001] This utility model belongs to the field of chemical production technology, specifically to a low-energy-consumption isobutyraldehyde separation system. Background Technology

[0002] Butyraldehyde and isobutyraldehyde are important intermediates in chemical production, widely used in plasticizers, coatings, and solvents. Due to their similar boiling points, traditional separation methods such as atmospheric distillation or single-column distillation suffer from high energy consumption and low efficiency. Current technologies often employ multi-column series or high-pressure distillation processes, but these methods involve complex equipment, high investment costs, and persistently high energy consumption. For example, conventional dual-column separation processes require additional reboilers and condensers, leading to significant heat loss and increased operating costs. Furthermore, insufficient mass transfer efficiency within the column and uneven gas distribution further reduce separation effectiveness and increase the difficulty of product purity control. In recent years, thermal coupling technology has been proposed to reduce energy consumption, but it still suffers from drawbacks such as low thermal integration efficiency and operational instability in practical applications. For instance, some thermal coupling systems, due to a lack of optimized column structure and distributor design, result in insufficient steam utilization or localized overheating, affecting separation efficiency.

[0003] Therefore, the development of a low-energy, high-efficiency, and stable separation system for isobutyraldehyde has become an urgent need in the industry.

[0004] In view of the above, this utility model is hereby proposed. Utility Model Content

[0005] The primary objective of this invention is to provide a low-energy-consumption isobutyraldehyde separation system that achieves efficient energy recovery and improved mass transfer efficiency through innovative thermal coupling design, optimized tower internal structure, and the application of spiral guide vanes.

[0006] In order to achieve the above-mentioned objectives of this utility model, the following technical solution is adopted:

[0007] A low-energy-consumption isobutyraldehyde separation system includes an atmospheric distillation column and a pressurized distillation column, wherein the atmospheric distillation column and the pressurized distillation column are connected by a thermally coupled pipeline;

[0008] The pressurized distillation column is equipped with a double-layer sieve tray. The upper sieve tray has a hole diameter of 4-6mm, the lower sieve tray has a hole diameter of 2-4mm, and the distance between the two sieve trays is 50-100mm. The pressurized distillation column is also equipped with an umbrella-shaped gas collector at the top.

[0009] The atmospheric distillation column is equipped with an alternating corrugated packing layer, the height of which is 1 / 3 to 1 / 2 of the column height, and the corrugation spacing is 10-20 mm.

[0010] This invention provides a low-energy-consumption n- and isobutyraldehyde separation system. Its core lies in achieving efficient and low-energy separation of n-butyraldehyde and isobutyraldehyde through specific equipment structure design and optimized thermal coupling process. The key components of this system include an atmospheric distillation column, a pressurized distillation column, and thermal coupling pipelines connecting the two. Each component is precisely designed to synergistically improve separation efficiency and reduce energy consumption.

[0011] First, the pressurized distillation column adopts a double-layer sieve tray structure. The upper sieve tray has a pore size of 4-6 mm, the lower sieve tray has a pore size of 2-4 mm, and the distance between the two sieve trays is 50-100 mm. This layered design can effectively optimize the contact efficiency of the gas and liquid phases. The larger pore size of the upper sieve tray helps to reduce pressure drop and reduce mist entrainment, while the smaller pore size of the lower sieve tray enhances the mass transfer effect, making it easier for the light component (isobutyraldehyde) to escape from the top of the column, while the heavy component (n-butyraldehyde) is enriched at the bottom of the column. In addition, the umbrella-shaped gas collector set at the top of the column can better collect the isobutyraldehyde gas flow accumulated at the top of the column, so that it can escape from the top of the pressurized column more effectively.

[0012] Secondly, the interior of the atmospheric distillation column uses a staggered corrugated packing layer with a packing layer height of 1 / 3 to 1 / 2 of the column height and a corrugation spacing of 10-20 mm. The geometric characteristics of the corrugated packing increase the gas-liquid contact area, while its staggered arrangement reduces flow dead zones, resulting in more uniform liquid distribution and significantly improved mass transfer efficiency. This design is particularly suitable for atmospheric distillation processes, enabling preliminary separation with lower energy consumption and providing optimized feed conditions for subsequent pressurized distillation.

[0013] As the core component connecting the two towers, the thermal coupling pipe has spiral guide vanes (with a pitch of 30-50 mm and a thickness of 1-2 mm) inside, which further optimizes the energy transfer efficiency. The spiral structure can extend the residence time of steam in the pipe, enhance the heat exchange effect, and reduce pressure drop loss, ensuring that steam is efficiently transferred from the pressurized distillation tower to the atmospheric distillation tower. This thermal coupling design makes full use of the high-temperature steam of the pressurized distillation tower as the heat source of the atmospheric distillation tower, which greatly reduces the additional energy consumption requirements of the reboiler in the traditional process and realizes the cascade utilization of energy.

[0014] From an overall process perspective, the technical solution of this utility model solves the industry problems of high energy consumption and low efficiency in traditional separation processes through structural innovation and system integration. The combination of double-layer sieve trays and umbrella-shaped gas collectors improves the separation performance of pressurized distillation columns, the corrugated packing layer optimizes the mass transfer process of atmospheric distillation columns, and the thermally coupled pipelines achieve efficient energy recovery. This collaborative design not only reduces equipment investment and operating costs, but also improves product purity and process stability, making it particularly suitable for large-scale industrial production.

[0015] Preferably, as a further feasible option, a guide tube is added between the double-layer sieve trays of the pressurized distillation column. The diameter of the guide tube is 1 / 5 to 1 / 4 of the column diameter, and the tube wall has vertical strip holes with a width of 2-3 mm and a spacing of 5-10 mm.

[0016] This invention further optimizes and improves the double-layer sieve tray structure of the pressurized distillation column by adding a key component, a flow guide tube. The addition of the flow guide tube significantly improves the fluid distribution between the trays, thereby enhancing the mass transfer efficiency of the entire separation system, reducing energy consumption, and improving operational stability. Structurally, the diameter of the flow guide tube is 1 / 5 to 1 / 4 of the column diameter. This ratio ensures sufficient flow cross-sectional area while effectively guiding the gas-liquid two-phase flow. A diameter that is too small will increase flow resistance and energy consumption; a diameter that is too small will... If the orifice is too large, it cannot effectively guide the flow, negating the purpose of structural optimization. The vertical strip-shaped holes in the guide tube wall are another key design element. These holes are 2-3 mm wide with a spacing of 5-10 mm. This specific array of orifices creates a unique fluid channel pattern. Compared to traditional circular holes, the vertical strip-shaped holes better adapt to the flow characteristics of the gas-liquid two phases in the vertical direction, reducing eddies and back-mixing. The width design of the strip-shaped holes ensures sufficient open area to reduce pressure drop while avoiding uneven gas-liquid distribution caused by excessively large openings. The optimized hole spacing ensures uniform fluid distribution after passing through the strip-shaped holes, preventing the formation of localized flow dead zones or excessive velocity gradients.

[0017] Furthermore, during the process of the gas-liquid two-phase flow rising from the lower sieve plate to the upper sieve plate, the cylindrical structure of the guide tube can constrain the radial diffusion of the fluid, forcing the fluid to move mainly along the axial direction. This constraint significantly reduces the lateral mixing of the fluid between the trays and improves the separation efficiency of each theoretical tray. Secondly, the special design of the strip-shaped orifice creates a controllable fluid redistribution mechanism. When the fluid passes through the strip-shaped orifice, moderate turbulence is generated. This controlled turbulence enhances interphase mass transfer without causing excessive energy loss. Finally, the presence of the guide tube changes the local pressure distribution between the trays, forming a pressure gradient that is conducive to gas-liquid separation, further optimizing the thermodynamic conditions of the separation process.

[0018] This invention solves several key problems inherent in traditional double-layer sieve tray distillation columns by introducing a flow guide tube: First, it avoids disordered mixing of the gas and liquid phases between the trays, which reduces the theoretical tray number and affects separation efficiency. Second, it reduces entrainment, as fine droplets in traditional designs are easily carried to the upper tray by the rising airflow, causing cross-contamination of the product. Third, it improves the uniformity of liquid distribution on the trays, preventing operational instability phenomena such as "dry trays" or "flooding." The combined effect of these improvements allows the distillation column to operate with higher throughput and lower energy consumption while maintaining product purity.

[0019] Preferably, as a further feasible option, an annular baffle is added below the umbrella-shaped gas collector of the pressurized distillation column. The width of the baffle is 1 / 10 to 1 / 8 of the column diameter, and the angle between the baffle surface and the horizontal plane is 10° to 15°.

[0020] Furthermore, this invention significantly improves the structure of the umbrella-shaped gas collector in the pressurized distillation column by adding a key component: an annular baffle. The addition of this baffle creatively optimizes the gas-liquid two-phase flow field distribution in the column top region, effectively solving industry problems such as mist entrainment and uneven liquid redistribution. This significantly improves the operational stability and separation efficiency of the entire separation system. The width of the annular baffle is designed to be 1 / 10 to 1 / 8 of the column diameter. This ratio ensures sufficient interception area while avoiding excessive obstruction of the rising airflow. Simultaneously, the angle between the baffle surface and the horizontal plane is set at 10°-15°. This precise angle design allows the intercepted liquid to form a stable thin film flow, preventing secondary entrainment of droplets and ensuring smooth liquid flow. An excessively large angle would... This design avoids liquid stagnation, and an excessively small angle can affect the interception effect. In addition, this invention selects the installation position of the annular liquid baffle below the umbrella-shaped gas collector. This layout ensures that the annular liquid baffle constructs a physical interception barrier, which can effectively capture the fine droplets entrained in the rising airflow. In traditional designs, these droplets often directly enter the subsequent isobutyraldehyde condensation system, which not only reduces the purity of isobutyraldehyde but also wastes materials. Secondly, the inclined surface formed by the liquid baffle guides the intercepted liquid to form a uniform falling film flow. This orderly liquid flow pattern avoids flow field disturbances caused by local accumulation and random dripping. Moreover, the space between the liquid baffle and the umbrella-shaped collector forms a dynamically balanced separation zone. In this zone, the gas and liquid phases reach the optimal separation state under the action of a specific pressure difference and surface tension.

[0021] Therefore, it can be concluded that the ratio of the width of the annular baffle plate to the tower diameter ensures structural strength and avoids vibration problems under high gas velocity conditions; the specific angled tilt design prevents the accumulation of solid deposits and reduces the risk of blockage. The baffle plate can be made of corrosion-resistant metal materials or treated with special coatings to adapt to slightly corrosive media such as n-butyraldehyde and isobutyraldehyde. The installation method can adopt a detachable connection for easy daily maintenance and cleaning.

[0022] Preferably, as a further feasible option, a porous support plate is also provided at the bottom of the corrugated packing layer of the atmospheric distillation column. The porous support plate has an opening ratio of 20%-30%, a pore diameter of 5-8 mm, and a plate thickness of 3-5 mm. A metal wire mesh layer with a mesh count of 40-60 is provided between the porous support plate and the corrugated packing layer.

[0023] This invention also makes key improvements to the corrugated packing support structure of atmospheric distillation columns. By adding a combination of porous support plates and a wire mesh layer, it solves long-standing technical problems in industrial packed columns such as packing deformation, uneven liquid distribution, and local channeling. The synergistic effect of the porous support plate and the wire mesh layer not only significantly improves the structural stability of the packing layer but also significantly improves the mass transfer efficiency of the entire column by optimizing the initial liquid distribution, resulting in a qualitative leap in the operational flexibility and separation accuracy of the entire separation system. The porous support plate adopts an opening ratio of 20%-30%, with the pore diameter controlled within the range of 5-8mm and the plate thickness set at 3-5mm, thereby ensuring sufficient mechanical strength while achieving optimal fluid throughput performance. A low opening ratio would lead to… This leads to a sharp increase in pressure drop, affecting the tower's processing capacity; excessively high porosity weakens the support strength, making it unable to withstand the static load of the packing layer for a long time. Precise control of the pore size avoids the accumulation of liquid on the surface of the support plate. A pore size range of 5-8mm can prevent flooding and ensure uniform gas distribution. The 3-5mm plate thickness design perfectly balances the relationship between structural strength and weight load, avoiding deformation due to being too thin and unnecessary weight increase due to being too thick. At the same time, the introduction of a 40-60 mesh metal wire mesh layer creates an ideal transition interface. Its fine mesh structure can effectively prevent packing particles from leaking down without significantly obstructing the rising airflow. In addition, the elasticity of the wire mesh can absorb the impact load caused by operational fluctuations, protecting the packing structure from damage.

[0024] Preferably, as a further feasible option, the thermally coupled pipeline is connected to the atmospheric distillation column via the circulation port of the atmospheric reboiler located at the bottom of the atmospheric distillation column, and the thermally coupled pipeline is connected to the pressurized distillation column via the outlet of the pressurized distillation column located at the top of the pressurized distillation column; a pressure control valve and an atmospheric reboiler are provided on the thermally coupled pipeline, the atmospheric reboiler is connected to the atmospheric distillation column via the circulation port of the atmospheric reboiler, and the pressure control valve is connected to the pressurized distillation column via the outlet of the pressurized distillation column; the atmospheric reboiler is also externally connected to a heat pump, and the heat pump is connected to the atmospheric distillation column outlet located at the bottom of the atmospheric distillation column; a feed liquid inlet is also provided in the middle of the atmospheric distillation column.

[0025] In this invention, the thermal coupling pipeline is the core component, which makes full use of the heat source in the pressurized distillation column to heat the material in the atmospheric distillation column, thereby reducing the introduction of additional heat.

[0026] Preferably, as a further feasible option, a material inlet is provided in the middle of the pressurized distillation column, the material inlet is connected to the outlet of the atmospheric distillation column provided at the top of the atmospheric column, and a condenser and a reflux tank are also provided in parallel between the material inlet and the outlet of the atmospheric distillation column, the condenser is connected to the outlet of the atmospheric distillation column, and the reflux tank is connected to the circulating feed inlet provided at the top of the atmospheric distillation column.

[0027] Preferably, as a further feasible option, the pressurized distillation column is also provided with a buffer reflux tank inlet, and the buffer reflux tank is connected to the pressurized distillation column through the buffer reflux tank inlet; the bottom of the pressurized distillation column is provided with a pressurized distillation column outlet, and the pressurized distillation column outlet and the outlet of the atmospheric distillation column converge and are connected to the n-butyraldehyde storage tank;

[0028] A reboiler is also provided on the outside of the pressurized distillation column, and the reboiler is connected to the outlet of the pressurized distillation column.

[0029] Preferably, as a further feasible option, it also includes an isobutyraldehyde storage tank, which is connected to the reboiler of the atmospheric distillation column; and a buffer reflux tank inlet is also provided between the reboiler of the atmospheric distillation column and the isobutyraldehyde storage tank, which is connected to the buffer reflux tank inlet.

[0030] Therefore, in summary, the low-energy-consumption n- and isobutyraldehyde separation system of this utility model achieves highly efficient and energy-saving separation of n-butyraldehyde and isobutyraldehyde through innovative thermal coupling design and optimized equipment structure. The entire process begins with the feeding stage of the mixed liquid into the atmospheric distillation column. The raw material liquid enters the system through the raw material liquid inlet located in the middle of the atmospheric distillation column. After entering the column, the mixed liquid is heated in the reboiler of the atmospheric distillation column to achieve vaporization. Subsequently, it gradually rises in the column and comes into contact with the condensate flowing down from the top of the column in a staggered corrugated packing layer with a height of 1 / 3 to 1 / 2 of the column height, achieving mass and heat transfer. The precise design of the packing corrugation spacing of 10-20mm creates a huge gas-liquid contact area while reducing flow dead zones. It is particularly noteworthy that the combination support system of a porous support plate with an opening rate of 20%-30% and a pore size of 5-8mm and a 40-60 mesh metal wire mesh layer at the bottom of the packing layer not only provides reliable mechanical support for the packing but also optimizes the liquid distribution, significantly improving the mass transfer efficiency.

[0031] During atmospheric distillation, due to the boiling point difference between n-butyraldehyde (boiling point 75.7℃) and isobutyraldehyde (boiling point 64.1℃), the lighter isobutyraldehyde component preferentially vaporizes. These vapors, carrying a large amount of heat energy, rise to the top of the column and flow out through the outlet of the atmospheric distillation column. After condensation by a condenser connected to the outlet, most of the liquid flows into the pressurized distillation column through the feed inlet located in the middle of the pressurized distillation column. A portion returns to the circulating feed inlet at the top of the atmospheric distillation column via a reflux tank, flowing back into the atmospheric distillation column as condensate. Simultaneously, at the bottom of the atmospheric distillation column... The material is discharged through the discharge system. Part of the material enters the reboiler of the atmospheric distillation column, and part flows into the n-butyraldehyde storage tank. The material flowing into the reboiler of the atmospheric distillation column exchanges heat with the isobutyraldehyde vapor flowing in through the thermal coupling pipe. Thus, the material in the atmospheric distillation column is heated by the isobutyraldehyde vapor from the pressurized distillation column. If the heat carried by the isobutyraldehyde vapor is insufficient, it can be heated by the heat pump connected to the outside of the reboiler of the atmospheric distillation column. At this time, the main function of the atmospheric distillation column is to perform preliminary separation of the mixture, distilling off most of the isobutyraldehyde from the top of the column, while the bottom of the column yields a material rich in n-butyraldehyde.

[0032] As the core equipment of the separation system, the pressurized distillation column receives material from the atmospheric distillation column at a specific location in the middle of the column. There, it undergoes mass and heat transfer through full contact with the condensate in a unique double-layer sieve tray. The upper sieve tray uses a larger aperture of 4-6 mm, while the lower tray uses a smaller aperture of 2-4 mm. The tray spacing is precisely controlled within the range of 50-100 mm. This gradient aperture design creates optimized gas-liquid contact conditions: the larger aperture in the upper layer effectively reduces pressure drop, while the smaller aperture in the lower layer significantly enhances mass transfer. Particularly noteworthy is the flow guide tube structure located between the double-layer sieve trays. Its diameter is strictly controlled within 1 / 5-1 / 4 of the column diameter, and the tube wall has vertical strip-shaped holes 2-3 mm wide, with a hole spacing controlled within 5-10 mm. This precise design effectively constrains the radial diffusion of the fluid, significantly reducing backmixing between trays and increasing the theoretical plate number by more than 20%. The umbrella-shaped gas collector installed at the top of the column allows the gas enriched at the top of the column to be better collected and escape from the top of the pressurized distillation column. Together with the annular baffle plate below, which is 1 / 10 to 1 / 8 of the column diameter and tilted at an angle of 10° to 15°, it forms a highly efficient gas-liquid separation system that can effectively intercept liquid droplets in the rising gas flow, reduce the amount of mist entrainment by more than 60%, and significantly improve the purity of the product at the top of the column.

[0033] In the pressurized distillation process, the material flowing into the pressurized distillation column from the middle section gradually undergoes re-vaporization of the mixture in the reboiler at the bottom of the column. Subsequently, the vaporized mixture rises in the pressurized distillation column and undergoes mass and heat transfer with the condensate in the double-layer sieve plate. The isobutyraldehyde vapor, carrying a large amount of heat, flows out from the pressurized distillation column outlet at the top of the column, flows through the heat-coupled pipeline into the atmospheric reboiler for condensation, and then enters the isobutyraldehyde storage tank. Meanwhile, the material rich in n-butyraldehyde flows out from the bottom of the pressurized distillation column. The pressure control valve installed on the heat-coupled pipeline allows the high-temperature steam (120-150℃) at the top of the pressurized distillation column to serve as a heat source for the atmospheric reboiler, realizing the cascade utilization of energy. At the same time, the materials from the bottom outlet of the pressurized distillation column and the outlet of the atmospheric column are combined and flow into the n-butyraldehyde storage tank.

[0034] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0035] (1) This utility model provides a low-energy-consumption isobutyraldehyde separation system. Through innovative thermal coupling design, optimized tower internal structure and application of spiral guide vanes, it achieves efficient energy recovery and improved mass transfer efficiency. Attached Figure Description

[0036] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0037] Figure 1 This is a structural diagram of a low-energy-consumption isobutyraldehyde separation system according to the present invention.

[0038] In the attached diagram:

[0039] 1. Feed inlet; 2. Atmospheric distillation column; 3. Condenser; 4. Reflux tank; 5. Pressure control valve; 6. Buffer reflux tank; 7. Pressurized distillation column; 8. Pressurized column reboiler; 9. n-Butyraldehyde storage tank; 10. Isobutyraldehyde storage tank; 11. Atmospheric column reboiler; 12. Corrugated packing layer; 13. Wire mesh layer; 14. Porous support layer; 15. Heat pump; 16. Umbrella-shaped gas collector; 17. Double-layer sieve tray; 18. Flow guide tube; 19. Annular baffle plate. Detailed Implementation

[0040] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are only some embodiments of this utility model, not all embodiments, and are only used to illustrate this utility model, and should not be regarded as limiting the scope of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0041] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0043] To more clearly illustrate the technical solution of this utility model, the following description is provided in the form of specific embodiments.

[0044] Example 1

[0045] The specific low-energy consumption analysis procedure for isobutyraldehyde according to this utility model is as follows:

[0046] The n-butyraldehyde mixture (n-butyraldehyde 55wt%, isobutyraldehyde 45wt%, initial temperature 45℃) is first heated to 65℃ in a preheater, and then discharged at a flow rate of 5m 3 The flow rate of the mixture is / h. It enters the separation system through the feed inlet 1 in the middle of the atmospheric distillation column 2. After entering the column, the mixture is first heated in the column bottom by the atmospheric reboiler 11. The heat source comes from the high temperature steam at the top of the pressurized distillation column 7 and the heat pump 15 of the external heat source. The steam is transported to the atmospheric reboiler 11 through the heat coupling pipeline. The heat coupling pipeline is equipped with a pressure control valve 5 to precisely adjust the steam pressure and ensure the stability of heat transfer. If the steam heat is insufficient, the external heat pump 15 will assist in heating to ensure that the column bottom temperature is maintained within a suitable range. After heating, the mixture gradually vaporizes. Since the boiling point of isobutyraldehyde is 64.1℃ lower than that of n-butyraldehyde (75.7℃), isobutyraldehyde vaporizes preferentially and rises to the top of the column.

[0047] The rising steam passes through an alternating corrugated packing layer 12 within the atmospheric distillation column 2. The height of the packing layer is one-third of the column height, and the corrugation spacing is 10 mm. This design significantly increases the gas-liquid contact area and reduces flow dead zones, resulting in more uniform liquid distribution and a substantial improvement in mass transfer efficiency. A porous support plate 14 with an opening ratio of 20%, a pore diameter of 5 mm, and a plate thickness of 3 mm is provided at the bottom of the packing layer. Its function is to support the packing layer and optimize liquid distribution. A metal wire mesh layer 13 with a mesh count of 40 is also provided between the porous support plate 14 and the corrugated packing layer 12 to further prevent packing particles from leaking down and enhance the uniformity of liquid distribution.

[0048] The isobutyraldehyde vapor at the top of the column enters the condenser 3 through the outlet of the atmospheric distillation column. The condensed liquid is divided into two parts: one part returns to the circulating feed port at the top of the atmospheric distillation column 2 through the reflux tank 4 as condensate; the other part enters the material input port in the middle of the pressurized distillation column 7 for further distillation separation. The stream at the bottom of the atmospheric distillation column 2 is rich in n-butyraldehyde. One part is discharged through the outlet of the atmospheric distillation column to the n-butyraldehyde storage tank 9, and the other part enters the reboiler 11 of the atmospheric column for circulating heating.

[0049] The material entering the pressurized distillation column 7 rises within the column and undergoes mass and heat transfer with the condensate flowing in from the top of the column on the double-layer sieve tray 17. The upper sieve tray has a pore size of 4 mm, the lower sieve tray has a pore size of 2 mm, and the distance between the two sieve trays is 50 mm. This layered design optimizes the contact efficiency between the gas and liquid phases: the larger pore size of the upper sieve tray reduces pressure drop and mist entrainment, while the smaller pore size of the lower sieve tray enhances mass transfer. A flow guide tube 18 with a diameter of 1 / 5 of the column diameter is provided between the double-layer sieve trays 17. The tube wall has vertical strip-shaped holes with a width of 2 mm and a spacing of 5 mm. The function of the flow guide tube 18 is to constrain the radial diffusion of the fluid, reduce disordered mixing between the trays, and thus improve separation efficiency.

[0050] The pressurized distillation column 7 is equipped with an umbrella-shaped gas collector 16 at the top for efficient collection of isobutyraldehyde vapor from the top of the column. Below the umbrella-shaped gas collector 16, an annular baffle plate 19 is added, with a width of 1 / 10 of the column diameter and an angle of 10° between the plate surface and the horizontal plane. The function of the annular baffle plate 19 is to intercept liquid droplets entrained in the rising gas flow and prevent them from entering the condensation system, thereby improving the purity of the product at the top of the column. The bottom of the column is heated by the pressurized column reboiler 8, which enriches the heavy component n-butyraldehyde at the bottom of the column. The isobutyraldehyde vapor at the top of the column returns to the atmospheric column reboiler 11 through a thermal coupling pipe, realizing the cascade utilization of heat. After that, the isobutyraldehyde vapor is condensed in the atmospheric column reboiler, and part of it flows into the isobutyraldehyde storage tank 10, while part of it flows into the pressurized distillation column 7 as condensate through the buffer reflux tank 6. The n-butyraldehyde stream from the bottom of the column enters the n-butyraldehyde storage tank 9 together with the stream from the bottom of the atmospheric distillation column 2. The isobutyraldehyde storage tank 10 receives the condensate from the atmospheric column reboiler 11.

[0051] Example 2

[0052] The specific low-energy consumption analysis procedure for isobutyraldehyde according to this utility model is as follows:

[0053] The n-butyraldehyde mixture (n-butyraldehyde 55wt%, isobutyraldehyde 45wt%, initial temperature 45℃) is first heated to 65℃ in a preheater, and then discharged at a flow rate of 5m 3The flow rate of the mixture is / h. It enters the separation system through the feed inlet 1 in the middle of the atmospheric distillation column 2. After entering the column, the mixture is first heated in the column bottom by the atmospheric reboiler 11. The heat source comes from the high temperature steam at the top of the pressurized distillation column 7 and the heat pump 15 of the external heat source. The steam is transported to the atmospheric reboiler 11 through the heat coupling pipeline. The heat coupling pipeline is equipped with a pressure control valve 5 to precisely adjust the steam pressure and ensure the stability of heat transfer. If the steam heat is insufficient, the external heat pump 15 will assist in heating to ensure that the column bottom temperature is maintained within a suitable range. After heating, the mixture gradually vaporizes. Since the boiling point of isobutyraldehyde is 64.1℃ lower than that of n-butyraldehyde (75.7℃), isobutyraldehyde vaporizes preferentially and rises to the top of the column.

[0054] The rising steam passes through an alternating corrugated packing layer 12 within the atmospheric distillation column 2. The height of the packing layer is half the height of the column, and the corrugation spacing is 20 mm. This design significantly increases the gas-liquid contact area and reduces flow dead zones, resulting in more uniform liquid distribution and a substantial improvement in mass transfer efficiency. A porous support plate 14 with an opening ratio of 30%, a pore diameter of 8 mm, and a plate thickness of 5 mm is provided at the bottom of the packing layer. Its function is to support the packing layer and optimize liquid distribution. A metal wire mesh layer 13 with a mesh count of 60 is also provided between the porous support plate 14 and the corrugated packing layer 12 to further prevent packing particles from leaking down and enhance the uniformity of liquid distribution.

[0055] The isobutyraldehyde vapor at the top of the column enters the condenser 3 through the outlet of the atmospheric distillation column. The condensed liquid is divided into two parts: one part returns to the circulating feed port at the top of the atmospheric distillation column 2 through the reflux tank 4 as condensate; the other part enters the material input port in the middle of the pressurized distillation column 7 for further distillation separation. The stream at the bottom of the atmospheric distillation column 2 is rich in n-butyraldehyde. One part is discharged through the outlet of the atmospheric distillation column to the n-butyraldehyde storage tank 9, and the other part enters the reboiler 11 of the atmospheric column for circulating heating.

[0056] The material entering the pressurized distillation column 7 rises within the column and undergoes mass and heat transfer through the double-layer sieve tray 17. The upper sieve tray has a pore size of 6 mm, the lower sieve tray has a pore size of 4 mm, and the distance between the two sieve trays is 100 mm. This layered design optimizes the contact efficiency between the gas and liquid phases: the larger pore size of the upper sieve tray reduces pressure drop and mist entrainment, while the smaller pore size of the lower sieve tray enhances mass transfer. A flow guide tube 18 with a diameter of 1 / 4 of the column diameter is provided between the double-layer sieve trays 17. The tube wall has vertical strip-shaped holes with a width of 3 mm and a spacing of 10 mm. The function of the flow guide tube 18 is to constrain the radial diffusion of the fluid, reduce disordered mixing between the trays, and thus improve separation efficiency.

[0057] The pressurized distillation column 7 is equipped with an umbrella-shaped gas collector 16 at the top for efficient collection of isobutyraldehyde vapor from the top of the column. Below the umbrella-shaped gas collector 16, an annular baffle plate 19 is added, with a width of 1 / 8 of the column diameter and an angle of 15° between the plate surface and the horizontal plane. The function of the annular baffle plate 19 is to intercept liquid droplets entrained in the rising gas flow, preventing them from entering the condensation system, thereby improving the purity of the product at the top of the column. The bottom of the column is heated by the pressurized column reboiler 8, causing the heavy component n-butyraldehyde to accumulate at the bottom of the column. The isobutyraldehyde vapor from the top of the column returns to the atmospheric pressure column reboiler 11 through a thermally coupled pipe, achieving... The heat is utilized in stages. After the isobutyraldehyde vapor is condensed in the reboiler of the atmospheric distillation column, part of it flows into the isobutyraldehyde storage tank 10, and part of it flows into the pressurized distillation column 7 as condensate through the buffer reflux tank 6. The n-butyraldehyde stream at the bottom of the column enters the n-butyraldehyde storage tank 9 together with the stream at the bottom of the atmospheric distillation column 2. The isobutyraldehyde storage tank 10 receives the condensate from the reboiler 11 of the atmospheric distillation column.

[0058] Example 3

[0059] The specific low-energy consumption analysis procedure for isobutyraldehyde according to this utility model is as follows:

[0060] The n-butyraldehyde mixture (n-butyraldehyde 55wt%, isobutyraldehyde 45wt%, initial temperature 45℃) is first heated to 65℃ in a preheater, and then discharged at a flow rate of 5m 3 The flow rate of the mixture is / h. It enters the separation system through the feed inlet 1 in the middle of the atmospheric distillation column 2. After entering the column, the mixture is first heated in the column bottom by the atmospheric reboiler 11. The heat source comes from the high temperature steam at the top of the pressurized distillation column 7 and the heat pump 15 of the external heat source. The steam is transported to the atmospheric reboiler 11 through the heat coupling pipeline. The heat coupling pipeline is equipped with a pressure control valve 5 to precisely adjust the steam pressure and ensure the stability of heat transfer. If the steam heat is insufficient, the external heat pump 15 will assist in heating to ensure that the column bottom temperature is maintained within a suitable range. After heating, the mixture gradually vaporizes. Since the boiling point of isobutyraldehyde is 64.1℃ lower than that of n-butyraldehyde (75.7℃), isobutyraldehyde vaporizes preferentially and rises to the top of the column.

[0061] The rising steam passes through an alternating corrugated packing layer 12 within the atmospheric distillation column 2. The height of the packing layer is 2 / 5 of the column height, and the corrugation spacing is 15 mm. This design significantly increases the gas-liquid contact area while reducing flow dead zones, resulting in more uniform liquid distribution and a substantial improvement in mass transfer efficiency. A porous support plate 14 with an opening ratio of 25%, a pore diameter of 6.5 mm, and a plate thickness of 4 mm is provided at the bottom of the packing layer. Its function is to support the packing layer and optimize liquid distribution. A metal wire mesh layer 13 with a mesh count of 50 is also provided between the porous support plate 14 and the corrugated packing layer 12 to further prevent packing particles from leaking down and enhance the uniformity of liquid distribution.

[0062] The isobutyraldehyde vapor at the top of the column enters the condenser 3 through the outlet of the atmospheric distillation column. The condensed liquid is divided into two parts: one part returns to the circulating feed port at the top of the atmospheric distillation column 2 through the reflux tank 4 as condensate; the other part enters the material input port in the middle of the pressurized distillation column 7 for further distillation separation. The stream at the bottom of the atmospheric distillation column 2 is rich in n-butyraldehyde. One part is discharged through the outlet of the atmospheric distillation column to the n-butyraldehyde storage tank 9, and the other part enters the reboiler 11 of the atmospheric column for circulating heating.

[0063] The material entering the pressurized distillation column 7 rises within the column and undergoes mass and heat transfer through a double-layer sieve tray 17. The upper sieve tray has a pore size of 5 mm, the lower sieve tray has a pore size of 3 mm, and the distance between the two sieve trays is 75 mm. This layered design optimizes the contact efficiency between the gas and liquid phases: the larger pore size of the upper sieve tray reduces pressure drop and mist entrainment, while the smaller pore size of the lower sieve tray enhances mass transfer. A flow guide tube 18 with a diameter of 9 / 40 of the column diameter is provided between the double-layer sieve trays 17. The tube wall has vertical strip-shaped holes with a width of 2.5 mm and a spacing of 7.5 mm. The function of the flow guide tube 18 is to constrain the radial diffusion of the fluid, reduce disordered mixing between the trays, and thus improve separation efficiency.

[0064] The pressurized distillation column 7 is equipped with an umbrella-shaped gas collector 16 at the top for efficient collection of isobutyraldehyde vapor from the top of the column. Below the umbrella-shaped gas collector 16, an annular baffle plate 19 is added, with a width of 9 / 80 of the column diameter and an angle of 12.5° between its surface and the horizontal plane. The function of the annular baffle plate 19 is to intercept liquid droplets entrained in the rising gas flow, preventing them from entering the condensation system, thereby improving the purity of the product at the top of the column. The bottom of the column is heated by the pressurized column reboiler 8, causing the heavy component n-butyraldehyde to accumulate at the bottom. The isobutyraldehyde vapor from the top of the column is returned to the atmospheric pressure column reboiler 11 through a thermally coupled pipe. To achieve cascade utilization of heat, after isobutyraldehyde vapor is condensed in the reboiler of the atmospheric distillation column, part of it flows into the isobutyraldehyde storage tank 10, and part of it flows into the pressurized distillation column 7 as condensate through the buffer reflux tank 6. The n-butyraldehyde stream from the bottom of the column enters the n-butyraldehyde storage tank 9 together with the stream from the bottom of the atmospheric distillation column 2. The isobutyraldehyde storage tank 10 receives the condensate from the reboiler 11 of the atmospheric distillation column.

[0065] Experiment Example 1: Performance Verification of a Low-Energy N-Isobutyraldehyde Separation System

[0066] Experimental objective: To verify the actual separation effect, energy consumption level, and operational stability of the low-energy-consumption isobutyraldehyde separation system described in this invention, and to compare it with the traditional dual-tower separation process;

[0067] Experimental group setup:

[0068] The separation system described in Examples 1-3 of this utility model is used for the separation of isobutyraldehyde;

[0069] The control group used a traditional dual-tower separation process;

[0070] The final data is shown in Table 1 below:

[0071] Table 1 Test Results

[0072]

[0073] Therefore, as can be seen from the above data, the low-energy-consumption n- and isobutyraldehyde separation system shown in Examples 1-3 of this utility model exhibits significant advantages in separation efficiency, energy consumption level, and operational stability through innovative thermal coupling design, optimized tower structure, and precisely controlled process parameters. In terms of separation effect, the n-butyraldehyde purity of Examples 1-3 reached 99.4%, 99.5%, and 99.6%, respectively, and the isobutyraldehyde purity was 99.3%, 99.4%, and 99.7%, respectively, which are significantly higher than the 98.2% and 97.8% of the traditional process. This improvement is mainly attributed to the synergistic optimization of the system structure: the double-layer sieve tray design of the pressurized distillation column creates a gradient mass transfer environment, with the upper large-aperture sieve reducing pressure drop and mist entrainment, and the lower small-aperture sieve enhancing gas-liquid contact efficiency; the introduction of the guide tube further constrains the radial diffusion of the fluid. At the same time, the staggered corrugated packing layer and the porous support plate-metal wire mesh combination structure of the atmospheric distillation column work together to achieve a liquid distribution uniformity of over 90%, effectively reducing flow dead zones; the combination of the umbrella-shaped gas collector and the annular baffle plate reduces mist entrainment by more than 60%. These structural innovations have jointly solved the purity bottleneck caused by uneven gas-liquid distribution in traditional processes.

[0074] In terms of energy consumption, the unit energy consumption of Examples 1-3 is 87.3, 86.2, and 85.1 kW·h / t, respectively, which is about 40% lower than the 142.6 kW·h / t of the traditional process. This indicates that the steam at the top of the pressurized distillation column of this invention, after being precisely regulated by the pressure control valve, serves as the heat source for the reboiler of the atmospheric distillation column, achieving cascaded energy utilization and reducing energy consumption. In addition, the temperature complementarity design of the bottom streams of the two columns further recovers waste heat, while the parallel condenser-reflux tank system realizes closed-loop circulation of materials, increasing the overall thermal energy utilization rate by more than 15%. This multi-level energy recovery mechanism fundamentally changes the drawback of the traditional dual-tower process that relies on external heat sources.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A low-energy-consumption isobutyraldehyde separation system, characterized in that, It includes an atmospheric distillation column and a pressurized distillation column, wherein the atmospheric distillation column and the pressurized distillation column are connected by a thermally coupled pipeline; The pressurized distillation column is equipped with a double-layer sieve tray. The upper sieve tray has a hole diameter of 4-6mm, the lower sieve tray has a hole diameter of 2-4mm, and the distance between the two sieve trays is 50-100mm. The pressurized distillation column is also equipped with an umbrella-shaped gas collector at the top. The atmospheric distillation column is equipped with an alternating corrugated packing layer, the height of which is 1 / 3 to 1 / 2 of the column height, and the corrugation spacing is 10-20 mm.

2. The low-energy consumption isobutyraldehyde separation system according to claim 1, characterized in that, A guide tube is added between the double-layer sieve trays of the pressurized distillation column. The diameter of the guide tube is 1 / 5 to 1 / 4 of the column diameter. The tube wall has vertical strip holes with a width of 2-3 mm and a spacing of 5-10 mm.

3. The low-energy consumption isobutyraldehyde separation system according to claim 1, characterized in that, An annular baffle plate is added below the umbrella-shaped gas collector of the pressurized distillation column. The width of the baffle plate is 1 / 10 to 1 / 8 of the column diameter, and the angle between the plate surface and the horizontal plane is 10° to 15°.

4. The low-energy-consumption isobutyraldehyde separation system according to claim 1, characterized in that, The bottom of the corrugated packing layer of the atmospheric distillation column is also provided with a porous support plate. The porous support plate has an opening rate of 20%-30%, a hole diameter of 5-8mm, and a plate thickness of 3-5mm. A metal wire mesh layer with a mesh count of 40-60 is provided between the porous support plate and the corrugated packing layer.

5. The low-energy-consumption isobutyraldehyde separation system according to claim 1, characterized in that, The thermally coupled pipeline is connected to the atmospheric distillation column via the reboiler circulation port at the bottom of the atmospheric distillation column, and to the pressurized distillation column via the outlet at the top of the pressurized distillation column. A pressure control valve and an atmospheric distillation column reboiler are installed on the thermally coupled pipeline. The atmospheric distillation column reboiler is connected to the atmospheric distillation column via its circulation port, and the pressure control valve is connected to the pressurized distillation column via its outlet. The atmospheric distillation column reboiler is also externally connected to a heat pump, which is connected to the atmospheric distillation column outlet at the bottom of the atmospheric distillation column. A feed inlet is also located in the middle of the atmospheric distillation column.

6. The low-energy-consumption isobutyraldehyde separation system according to claim 5, characterized in that, The pressurized distillation column is provided with a material inlet in the middle, which is connected to the outlet of the atmospheric distillation column at the top of the atmospheric column. A condenser and a reflux tank are also provided in parallel between the material inlet and the outlet of the atmospheric distillation column. The condenser is connected to the outlet of the atmospheric distillation column, and the reflux tank is connected to the circulating feed inlet at the top of the atmospheric distillation column.

7. The low-energy-consumption isobutyraldehyde separation system according to claim 6, characterized in that, The pressurized distillation column is also equipped with a buffer reflux tank inlet, and the buffer reflux tank is connected to the pressurized distillation column through the buffer reflux tank inlet; the bottom of the pressurized distillation column is equipped with a pressurized distillation column outlet, and the pressurized distillation column outlet and the outlet of the atmospheric distillation column converge and are connected to the n-butyraldehyde storage tank. A reboiler is also provided on the outside of the pressurized distillation column, and the reboiler is connected to the outlet of the pressurized distillation column.

8. The low-energy-consumption isobutyraldehyde separation system according to claim 7, characterized in that, It also includes an isobutyraldehyde storage tank, which is connected to the atmospheric pressure tower reboiler; and a buffer reflux tank inlet is provided between the atmospheric pressure tower reboiler and the isobutyraldehyde storage tank, which is connected to the buffer reflux tank inlet.

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