Batch rectification device for recovering centrifugal mother liquor
By adding switch valves and setting up intermediate tanks in the batch distillation device, flexible switching of batch distillation/distillation system and efficient separation of the material system are achieved, which solves the problems of high investment, slow processing and high energy consumption in the existing devices, and improves product quality and yield.
Patent Information
- Application Number
- CN202420557361.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-21
- Publication Date
- 2025-03-11
- Estimated Expiration
- 2034-03-21
AI Technical Summary
When recycling centrifugal mother liquor, the existing batch distillation device has high investment cost, long processing time, and high energy consumption. The yield of single batch heavy-phase products is low, which affects the replacement time of the next batch distillation.
An intermittent distillation device is designed. By adding multiple switch valves to the original system, the switching of the intermittent distillation/distillation system is achieved through the change of valve status, simplifying the operation process of the equipment, and an intermediate tank is set up on the top of the tower to separate heterogeneous substance systems and improve product quality and yield.
It effectively reduces investment costs and processing time, improves the yield of single batches of heavy-phase products, reduces energy consumption, and improves product quality.
Smart Images
Figure CN222593532U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to an intermittent distillation device, in particular to an intermittent distillation device for recovering centrifugal mother liquor in fine chemical industries such as medicine and pesticide. Background Art
[0002] In fine chemical industries such as medicine and pesticides, especially in the production process of raw material pharmaceutical companies, there is a problem of recycling solvent waste liquid, especially when the waste liquid contains non-volatile components (such as solid phase), the residual liquid cannot be recycled as the final product, and the residual product needs to be separated from the residual liquid.
[0003] In the prior art, common methods for recovering centrifugal mother liquor include distillation, membrane separation, resin adsorption, etc.
[0004] The distillation (intermittent) method uses the difference in volatility of each component in the mixture to separate and purify substances. Usually, the raw materials are pre-distilled to discharge the non-volatile substances from the system, and then intermittent distillation is used to separate and recover the light and heavy phases; or after the light phase products and transition fractions of intermittent distillation are fully extracted, the heavy phase products are distilled along the original distillation system and condensed at the top of the tower for recovery.
[0005] Membrane separation uses a selectively permeable membrane as the separation medium. When there is a driving force (concentration difference, pressure difference, temperature difference, etc.) on both sides of the membrane, the components of the mixture selectively pass through the membrane to achieve the purpose of separation and purification.
[0006] The resin adsorption method utilizes polar or non-polar interactions to adsorb polar substances onto non-polar resins. This interaction is achieved through the interaction of positive and negative charges during contact to achieve resin adsorption; and then through desorption, the solvent is recovered.
[0007] In conventional intermittent distillation devices, it is usually necessary to set up a separate pre-distillation device (or use the original intermittent distillation device, which cannot achieve continuous pre-distillation-distillation, has low efficiency and long processing time) to separate the kettle residue from the material, resulting in high investment costs for the device and complex device processes; and after recovering the light phase products and transition fractions, the heavy phase is completely distilled from the distillation tower and extracted from the system. The phenomenon of liquid retention in the distillation tower will cause a significant increase in the output of the transition fraction, and the second distillation will result in high energy consumption and a low yield of a single batch of heavy phase products; and it will cause high levels of heavy phase products to be distributed in each section of the distillation tower, which will greatly extend the replacement time for the next batch of distillation.
[0008] Membrane separation has obvious advantages in energy saving and environmental protection. However, its large-scale application is limited by its disadvantages such as the short service life of the membrane, the need for frequent cleaning and replacement, and the high one-time investment cost.
[0009] The resin adsorption method avoids the disadvantages of short membrane service life and high investment cost, but it has high selectivity for adsorbed substances, and the selection and implementation of regeneration schemes limits its large-scale application. Utility Model Content
[0010] The utility model provides an intermittent distillation device for recovering centrifugal mother liquor, which aims to overcome the above-mentioned shortcomings of the prior art, reduce investment costs and shorten processing time.
[0011] The technical solution of the utility model is as follows: an intermittent distillation device for recovering centrifugal mother liquor, the structure of which comprises an intermittent distillation reactor, a distillation tower, a condenser, an intermediate tank, a heavy phase product tank and a light phase product tank, wherein the outlet of the intermittent distillation reactor is connected to the inlet of the bottom of the distillation tower, the intermittent distillation reactor is also provided with a raw material feed inlet, a reactor residue extraction outlet and a heat medium inlet and outlet, the top outlet of the distillation tower is connected to the inlet of the condenser, the condenser outlet is respectively connected to the inlet of the intermediate tank and the inlet of the heavy phase product tank through branch pipelines, the reflux outlet of the intermediate tank is connected to the reflux inlet of the top of the distillation tower, the outlet of the intermediate tank is connected to the inlet of the light phase product tank, the intermediate tank is also provided with a decantation phase extraction outlet, a second switch valve is provided on the pipeline between the outlet of the distillation reactor and the inlet of the bottom of the distillation tower, a fourth switch valve is provided on the pipeline between the outlet of the distillation tower and the inlet of the condenser, a bypass pipeline is connected between the pipeline between the fourth switch valve and the inlet of the condenser and the pipeline between the second switch valve and the outlet of the distillation reactor, and a third switch valve is provided on the bypass pipeline, and a sixth switch valve is provided on the branch pipeline between the outlet of the condenser and the inlet of the intermediate tank. By adding a switch valve to the original system, the switching of the intermittent distillation / distillation system can be achieved by changing the valve state, which is convenient and quick, and no modification of pipelines and equipment is required. An intermediate tank is set at the top of the tower. When the system produced from the top of the tower is a homogeneous system, it normally functions as a distillation reflux tank; when the condensed system at the top of the tower is a heterogeneous system (or free water phase), the product quality and yield can be improved by re-stratification and extraction of the decantation phase.
[0012] Preferably, a fifth switch valve is provided on the branch pipeline between the condenser outlet and the heavy phase product tank inlet, so as to avoid contamination of the intermediate tank and the corresponding light phase / transition fraction extraction and reflux pipelines during the collection of the heavy phase product.
[0013] Preferably, the bottom outlet of the distillation tower is connected to the inlet of the intermittent distillation reactor, and a first switch valve is provided on the pipeline between the bottom outlet of the distillation tower and the inlet of the intermittent distillation reactor. The pipeline is a reactor liquid phase reflux pipeline, and the first switch valve can prevent the material in the tower from flowing back into the reactor after the tower reactor product is qualified, thereby preventing the tower reactor product quality from decreasing.
[0014] Preferably, a transition fraction tank is further included, and the outlet of the intermediate tank is connected to the inlet of the light phase product tank and the inlet of the transition fraction tank through branch pipelines, respectively, so as to cope with the situation that the quality of the light phase product drops to the point where it does not meet the demand.
[0015] Preferably, sampling ports are respectively provided on the pipelines between the condenser outlet and the intermediate tank reflux outlet and the top reflux inlet of the distillation tower.
[0016] The advantages of this utility model are: reasonable structural design, adding a control valve inside the intermittent distillation device, and controlling each stage of intermittent distillation / distillation through the operating state of the valve; and adding an intermediate tank on the top of the tower, for the system containing free water phase (or other two liquid phases), the decantation phase is extracted to achieve the high quality requirements of the product. Compared with the traditional centrifugal mother liquor treatment device, it can effectively reduce investment costs and shorten processing time. Specifically,
[0017] 1) Convenient and practical: On the basis of the original intermittent distillation device, multiple switch valves are added. Different products can be extracted by switching the valves. In the process of extracting the heavy phase of the tower, the original top condenser equipment is used, which does not increase equipment investment and does not pollute the original extraction / reflux equipment and pipelines. It is highly practical. Remote control can also be used to switch the valves, which is convenient to operate and safe. Adding a valve to the liquid reflux pipeline at the bottom of the distillation tower can prevent the material in the tower from returning to the reactor at the end of the distillation, which will cause the quality of the heavy phase product in the tower to decrease.
[0018] 2) Strong functionality: Based on the original intermittent distillation system, the system retains its functions. For systems that do not contain difficult-to-volatilize / solid phases, the light phase and transition fractions can be collected from the top of the tower normally, and the heavy phase can be collected from the bottom of the tower to achieve solvent recovery; through dynamic valve switching, the centrifugal mother liquor can also be quickly recovered. An intermediate tank is set on the top of the tower, which can be used as a normal reflux tank and the separation of heterogeneous systems, which can effectively improve product quality and yield. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 The utility model is a schematic structural diagram of an intermittent distillation device for recovering centrifugal mother liquor.
[0020] In the figure, 1 is an intermittent distillation reactor, 2 is a distillation tower, 3 is a condenser, 4 is an intermediate tank, 5 is a heavy phase product tank, 6 is a light phase product tank, 7 is a transition fraction tank, 81 is a first switch valve, 82 is a second switch valve, 83 is a third switch valve, 84 is a fourth switch valve, 85 is a fifth switch valve, and 86 is a sixth switch valve. DETAILED DESCRIPTION
[0021] The present invention is further described in detail below in conjunction with embodiments and specific implementation methods.
[0022] like Figure 1As shown, an intermittent distillation device for recovering centrifugal mother liquor comprises an intermittent distillation reactor 1, a distillation tower 2, a condenser 3, an intermediate tank 4, a heavy phase product tank 5, a light phase product tank 6 and a transition fraction tank 7, wherein the outlet of the intermittent distillation reactor 1 is connected to the bottom inlet of the distillation tower 2, the bottom outlet of the distillation tower 2 is connected to the inlet of the intermittent distillation reactor 1, the intermittent distillation reactor 1 is also provided with a raw material feed inlet, a reactor residue outlet and a heat medium inlet and outlet, the top outlet of the distillation tower 2 is connected to the inlet of the condenser 3, the outlet of the condenser 3 is respectively connected to the inlet of the intermediate tank 4 and the inlet of the heavy phase product tank 5 through branch pipelines, the reflux outlet of the intermediate tank 4 is connected to the top reflux inlet of the distillation tower 2, the outlet of the intermediate tank 4 is respectively connected to the inlet of the light phase product tank 6 and the inlet of the transition fraction tank 7 through branch pipelines, and the intermediate tank 4 is also provided with a decantation phase outlet.
[0023] A first switch valve 81 is provided on the pipeline between the bottom outlet of the distillation tower 2 and the inlet of the intermittent distillation reactor 1 .
[0024] A second switch valve 82 is provided on the pipeline between the outlet of the rectification reactor 1 and the bottom inlet of the rectification tower 2 .
[0025] A fourth switch valve 84 is provided on the pipeline between the top outlet of the distillation tower 2 and the inlet of the condenser 3 .
[0026] A bypass pipeline is connected between the pipeline between the fourth switch valve 84 and the inlet of the condenser 3 and the pipeline between the second switch valve 82 and the outlet of the distillation reactor 1, and a third switch valve 83 is provided on the bypass pipeline.
[0027] A fifth switch valve 85 is provided on the branch pipeline between the outlet of the condenser 3 and the inlet of the heavy phase product tank 5 .
[0028] A sixth switch valve 86 is provided on the branch line between the outlet of the condenser 3 and the inlet of the intermediate tank 4 .
[0029] Sampling ports are respectively arranged on the pipelines between the outlet of the condenser 3 and the reflux outlet of the intermediate tank 4 and the reflux inlet at the top of the distillation tower 2 .
[0030] According to the above structure, when working, firstly, the centrifugal mother liquor to be recovered is pumped into the intermittent distillation reactor 1 at one time, the third switch valve 83 and the fifth switch valve 85 are closed, and the other valves are opened normally;
[0031] Secondly, the heat medium of the intermittent distillation reactor 1 is turned on to heat up and reflux the distillation system, and the full reflux state is maintained. Under the heating of the reactor heat medium, the light phase product will first gather gradually toward the top of the distillation tower 2 and be extracted due to its low boiling point and strong volatility;
[0032] After the light phase product at the top of the distillation tower 2 is qualified, the appropriate reflux ratio is controlled to be extracted to the light phase product tank 6;
[0033] When the quality of the light phase product drops to the point where it does not meet the demand, the transition fraction (if any) is extracted and collected into the transition fraction tank 7 (which can be applied to the next batch according to the situation) (when the light phase material content in the system becomes lower and lower, some heavy phase materials will gradually accumulate along the tower section, thereby affecting the quality of the light phase product at the top of the tower, so the transition fraction needs to be extracted until the bottom product meets the quality requirements);
[0034] After the heavy phase material product in the intermittent distillation reactor 1 is qualified, stop collecting the transition fraction; close the second switch valve 82, the fourth switch valve 84, and the sixth switch valve 86 accordingly, and open the third switch valve 83 and the fifth switch valve 85. At this time, the distilled gas phase does not pass through the inside of the distillation tower 2, but directly enters the top condenser 3 for condensation, and prepares to distill and recover the heavy phase product in the reactor to the heavy phase product tank 5. At the same time, the first switch valve 81 should be closed to prevent the material in the distillation tower 2 from flowing back into the reactor, causing the tower reactor product to be unqualified, and it can be used as the tower liquid for the next batch of processing, avoiding the energy loss of multiple distillations, and to a certain extent improving the yield of a single batch of heavy phase products;
[0035] After the distillation of the heavy phase material is completed, the heat medium of the intermittent distillation reactor 1 is turned off, the residue in the reactor is discharged out of the system after cooling down, the valve state is restored, and the system is ready to process the next batch of materials. Example 1
[0036] The composition and output of the centrifuged mother liquor produced during the production process of a certain API company are as follows: 51.91% (mass fraction, the same below) of isopropanol, 44.8% of ethyl acetate, 0.93% of cyclohexane, 2.37% of water and 190kg of kettle residue, with a single batch of 6000kg of mother liquor; the requirements for the recovered product are 27-31% of ethyl acetate, ≤0.5% of cyclohexane, and 69-73% of isopropanol.
[0037] Analysis of the mother liquor feed composition shows that the top of the tower is produced as light phase azeotropic impurities (initial composition is about 87% cyclohexane and 12% water). After the cyclohexane is produced, the main composition is high content ethyl acetate (about 75%), isopropanol (about 17%) and a small amount of water (about 5%). The isopropanol content in the bottom of the tower continues to increase with the production of the top of the tower to meet the product recovery requirements, and then the product is distilled and collected in the product tank by means of distillation; this process does not consider the collection of transition fractions (transition fraction tank 7 is idle or cancelled).
[0038] The main equipment parameters are as follows: the number of theoretical plates of the distillation tower 2 is 20, the nominal volume of the intermittent distillation reactor 1 is 6m³, the heat exchange area of the condenser 3 is 25㎡ (the cooling medium is circulating water), the light phase product tank 6 is 5m³, and the heavy phase product tank 5 is 5m³.
[0039] The following are the detailed steps:
[0040] First, confirm the working status of each valve, open the second switch valve 82, the fourth switch valve 84, the sixth switch valve 86, and the first switch valve 81, close the third switch valve 83 and the fifth switch valve 85, and inject 6000 kg of raw materials into the intermittent distillation reactor 1 at one time, and start the reactor heat medium feed to heat up and reflux the system.
[0041] After the system is stable, the reflux ratio is controlled to 5 to continuously extract the light component. During the process, the tower top / bottom temperature will continue to rise, and the isopropanol content in the tower bottom will continue to rise. When the tower bottom reaches the product quality requirement, the tower bottom temperature is about 80.7℃, the tower top temperature is 73.9℃, and the tower top extraction is stopped; at this time, the material composition in the kettle is as follows: 70% isopropanol, 29.5% ethyl acetate, and 0.5% water.
[0042] At the same time, the second switch valve 82, the fourth switch valve 84, the sixth switch valve 86, and the first switch valve 81 are remotely closed, and the third switch valve 83 and the fifth switch valve 85 are opened. The product in the kettle is distilled and condensed through the condenser 3 and collected into the heavy phase product tank 5 until all the products are distilled out.
[0043] After the heavy phase product is collected, the heat medium feed to the reactor is closed, and the reactor residue is taken out of the system. At this point, the single batch of mother liquor processing is completed, and the valve state is restored before the next batch of mother liquor processing.
[0044] The intermittent distillation system can be controlled by DCS or PLC as required. Example 2
[0045] The composition and output of the centrifuged mother liquor produced during the production process of a certain API company are as follows: 98.85% (mass fraction, the same below) of isopropyl acetate, 1.15% of water and 12 kg of kettle residue, with a single batch of mother liquor of 9000 kg; the quality requirement for the recovery of isopropyl acetate is ≥99.5%.
[0046] Analysis of the mother liquor composition shows that isopropyl acetate and water are azeotropic, the azeotropic temperature under normal pressure is 73.3°C, and the azeotropic composition is 83.5% isopropyl acetate and 16.5% water. Intermittent distillation is used for separation, and isopropyl acetate is used to take the water in the kettle out of the system. The content of isopropyl acetate in the tower bottom will gradually increase until the content meets the demand.
[0047] The main equipment parameters are as follows: the number of theoretical plates of the distillation tower 2 is 10, the nominal volume of the intermittent distillation reactor 1 is 10m³, the heat exchange area of the condenser 3 is 20㎡ (the cooling medium is circulating water), the light phase product tank 6 is 1m³, the transition fraction tank 7 is 1m³, and the heavy phase product tank 5 is 10m³.
[0048] The following are the detailed steps:
[0049] First, adjust the working status of each valve, open the second switch valve 82, the fourth switch valve 84, the sixth switch valve 86, and the first switch valve 81, close the third switch valve 83 and the fifth switch valve 85, and inject 9000 kg of raw materials into the intermittent distillation reactor 1 at one time, and simultaneously start the reactor heat medium to heat up and reflux the system.
[0050] After the system is stabilized, the reflux ratio is controlled to 2 to continuously extract the light component (azeotropic composition) to the light component product tank 6; during the process, the tower top / bottom temperature will continue to rise, and the isopropyl acetate content in the bottom will continue to rise.
[0051] When the water content at the top of the tower begins to decrease (part of it is isopropyl acetate outside the azeotropic composition), the temperature in the tower changes sharply during this process; switch the top of the tower to the transition fraction tank 7, and control the reflux ratio to 2 for continuous extraction. When the isopropyl acetate product in the bottom of the tower meets the quality requirements, the bottom temperature is about 88.3°C, and the composition is: 99.5% isopropyl acetate, 0.5% water, and the top of the tower is stopped; the transition fraction collected in the process can be distilled and recovered together with the next batch of raw materials.
[0052] At the same time, the second switch valve 82, the fourth switch valve 84, the sixth switch valve 86, and the first switch valve 81 are remotely closed, and the third switch valve 83 and the fifth switch valve 85 are opened. The product in the kettle is distilled and condensed through the condenser 3 and collected into the heavy phase product tank 5 until all the products are distilled out.
[0053] After the heavy phase product is collected, the heat medium feed to the reactor is closed, and the reactor residue is taken out of the system. At this point, the single batch of mother liquor processing is completed, and the valve state is restored before the next batch of mother liquor processing.
[0054] The intermittent distillation system can be controlled by DCS or PLC as required.
[0055] All the components mentioned above are prior art, and those skilled in the art can use any model and existing design that can achieve their corresponding functions.
[0056] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.
Claims
1. An intermittent distillation device for recovering centrifugal mother liquor, characterized in that: The invention comprises an intermittent distillation reactor (1), a distillation tower (2), a condenser (3), an intermediate tank (4), a heavy phase product tank (5) and a light phase product tank (6), wherein the outlet of the intermittent distillation reactor (1) is connected to the bottom inlet of the distillation tower (2), the intermittent distillation reactor (1) is also provided with a raw material feed inlet, a reactor residue outlet and a heat medium inlet and outlet, the top outlet of the distillation tower (2) is connected to the inlet of the condenser (3), the outlet of the condenser (3) is respectively connected to the inlet of the intermediate tank (4) and the inlet of the heavy phase product tank (5) through branch pipelines, the reflux outlet of the intermediate tank (4) is connected to the reflux inlet of the top of the distillation tower (2), the outlet of the intermediate tank (4) is connected to the light phase product tank (5) The intermediate tank (4) is also provided with a decantation phase extraction outlet, a second switch valve (82) is provided on the pipeline between the outlet of the rectification reactor (1) and the bottom inlet of the rectification tower (2), a fourth switch valve (84) is provided on the pipeline between the top outlet of the rectification tower (2) and the inlet of the condenser (3), a bypass pipeline is connected between the pipeline between the fourth switch valve (84) and the inlet of the condenser (3) and the pipeline between the second switch valve (82) and the outlet of the rectification reactor (1), and a third switch valve (83) is provided on the bypass pipeline, and a sixth switch valve (86) is provided on the branch pipeline between the outlet of the condenser (3) and the inlet of the intermediate tank (4).
2. An intermittent distillation device for recovering centrifugal mother liquor according to claim 1, characterized in that: A fifth switch valve (85) is provided on the branch pipeline between the outlet of the condenser (3) and the inlet of the heavy phase product tank (5).
3. The intermittent distillation device for recovering centrifugal mother liquor according to claim 1, characterized in that: The bottom outlet of the distillation tower (2) is connected to the inlet of the intermittent distillation reactor (1), and a first switch valve (81) is provided on the pipeline between the bottom outlet of the distillation tower (2) and the inlet of the intermittent distillation reactor (1).
4. The intermittent distillation device for recovering centrifugal mother liquor according to claim 1, characterized in that: It also includes a transition distillate tank (7), and the outlet of the intermediate tank (4) is connected to the inlet of the light phase product tank (6) and the inlet of the transition distillate tank (7) through branch pipelines.
5. The intermittent distillation device for recovering centrifugal mother liquor according to claim 1, characterized in that: Sampling ports are respectively provided on the pipelines between the outlet of the condenser (3), the reflux outlet of the intermediate tank (4) and the reflux inlet at the top of the distillation tower (2).