Nitrile compound refining system and amine compound preparation system
By integrating distillation and simulated moving bed technologies, and combining separation towers, simulated moving beds, and recovery towers, the problems of high energy consumption and low efficiency in isomer separation of nitrile compounds have been solved, enabling efficient separation and large-scale continuous production of high-purity nitrile compounds.
Patent Information
- Application Number
- CN202522464638.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-20
- Publication Date
- 2026-01-16
- Estimated Expiration
- 2035-11-20
AI Technical Summary
Existing technologies are energy-intensive and inefficient in separating isomer impurities in nitrile compounds, making it difficult to achieve high-purity separation, especially in the production of adiponitrile and related compounds, where isomers such as 2-methylglutaronitrile and ethylbutadionitrile present significant challenges.
By employing integrated distillation technology and simulated moving bed (SMB) adsorption separation technology, materials are initially separated through a separation tower, and then finely separated using a simulated moving bed. Combined with a recovery tower and a distillation tower, this achieves efficient separation of isomers and recycling of solvents, reducing solvent consumption and waste emissions.
It achieves the separation of high-purity nitrile compounds, reduces energy consumption, improves separation efficiency and product recovery rate, and is suitable for large-scale continuous production.
Smart Images
Figure CN223800090U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of nitrile compound separation and purification, and particularly relates to a nitrile compound purification system and an amine compound preparation system. BACKGROUND
[0002] In the production process of nitrile compounds, raw materials or intermediate products are often accompanied by isomer impurities with similar structures and close boiling points. For example, in the production process of adiponitrile (ADN) and related compounds, C6 dinitrile isomers such as 2-methylglutaronitrile (2-MGN) and ethylsuccinonitrile (ESN) are generated. These isomers seriously affect the quality of the final product and must be separated.
[0003] In related technologies, distillation technology is used for separation, such as gradually separating target products through multiple vacuum rectification column systems connected in series, or crystallization technology is used for separation, such as achieving deep purification through solvent crystallization, for example, using alkanols and other solvents to preferentially crystallize and precipitate target products at low temperatures.
[0004] However, due to the small difference in boiling points of isomer impurities, distillation and crystallization processes need to rely on high-energy consumption equipment or extend the operation time to achieve the target purity, which is high in energy consumption and low in efficiency. CONTENT OF THE INVENTION
[0005] The present application provides a nitrile compound purification system and an amine compound preparation system, which realizes efficient separation of isomer impurities with close boiling points and reduces energy consumption.
[0006] In order to achieve the above purpose, the present application provides a nitrile compound purification system, comprising: a separation column, the separation column being provided with a first feed inlet, a column top outlet and a column bottom outlet; a simulated moving bed, the simulated moving bed being provided with a second feed inlet, a first outlet, a second outlet and a solvent inlet, the second feed inlet being communicated with the column top outlet, the second outlet being communicated with the separation column; a recovery column, the recovery column being provided with a third feed inlet, a third outlet and a fourth outlet, the third feed inlet being communicated with the first outlet of the simulated moving bed, the third outlet being communicated with the solvent inlet of the simulated moving bed, and the fourth outlet being used for outputting a first compound; and a rectification column, the rectification column being provided with a fourth feed inlet and a fifth outlet, the fourth feed inlet being communicated with the column bottom outlet of the separation column, and the fifth outlet being used for outputting a second compound.
[0007] In a possible implementation manner, the nitrile compound purification system provided by the present application further comprises a circulation pipeline, one end of the circulation pipeline being communicated with the solvent inlet of the simulated moving bed, and the other end of the circulation pipeline being communicated with the third outlet of the recovery column.
[0008] In a possible implementation manner, the nitrile compound purification system provided by the present application further comprises a supplement pipeline, the supplement pipeline being communicated with the solvent inlet of the simulated moving bed.
[0009] In a possible implementation, the nitrile compound refining system provided in the present application includes the simulated moving bed comprising N adsorbent-filled chromatographic columns, N is greater than or equal to 6 and less than or equal to 24.
[0010] In a possible implementation, the nitrile compound refining system provided in the present application, in the height direction of the simulated moving bed, the solvent inlet of the simulated moving bed is located at the bottom end of the simulated moving bed, the second feed inlet of the simulated moving bed is higher than the solvent inlet, and the material entering the second feed inlet is countercurrently contacted with the desorbent entering the solvent inlet.
[0011] In a possible implementation, the nitrile compound refining system provided in the present application further comprises a buffer tank, the buffer tank is located between the separation column and the simulated moving bed, and the buffer tank is in communication with the overhead outlet and the second feed inlet of the simulated moving bed, respectively.
[0012] In a possible implementation, the nitrile compound refining system provided in the present application, the boiling point of the second compound is greater than the boiling point of the first compound.
[0013] In a possible implementation, the nitrile compound refining system provided in the present application, the first compound is ethyl succinonitrile, and the second compound is 2-methylglutaronitrile.
[0014] In a possible implementation, the nitrile compound refining system provided in the present application, the desorbent input by the solvent inlet is toluene or p-diethylbenzene;
[0015] And / or, the adsorbent in the simulated moving bed is 13X molecular sieve or spherical silica gel modified by-CN group.
[0016] In a possible implementation, the nitrile compound refining system provided in the present application, the rectifying column is further provided with a heavy impurity outlet.
[0017] The present application also provides an amine compound preparation system comprising the nitrile compound refining system of any one of the above embodiments.
[0018] The application provides a nitrile compound refining system and an amine compound preparation system. The system is provided with a first feed inlet, a tower top outlet and a tower kettle outlet through a separation tower; a simulated moving bed is provided with a second feed inlet, a first outlet, a second outlet and a solvent inlet, the second feed inlet is communicated with the tower top outlet, and the second outlet is communicated with the separation tower; a recovery tower is provided with a third feed inlet, a third outlet and a fourth outlet, the third feed inlet is communicated with the first outlet of the simulated moving bed, the third outlet is communicated with the solvent inlet of the simulated moving bed, and the fourth outlet is used for outputting a first compound; and a rectifying tower is provided with a fourth feed inlet and a fifth outlet, the fourth feed inlet is communicated with the tower kettle outlet of the separation tower, and the fifth outlet is used for outputting a second compound. The application realizes the separation of isomer impurities with similar boiling points by integrating the rectification technology and the adsorption separation technology of the simulated moving bed (SMB), adding the simulated moving bed on the basis of the rectifying tower, and realizing the fine separation of the preliminarily separated materials (such as isomers (ESN) with low boiling points) in the simulated moving bed, removing residual impurity isomers (2-MGN), and obtaining the first compound, such as the ESN product with high purity, through the recovery tower. And the preliminarily separated materials (such as isomers (2-MGN) with high boiling points and heavy impurities) are further purified in the rectifying tower to obtain the second compound, and meanwhile, the role of batch separation of the rectifying tower is played to realize large-scale continuous production. In addition, the third outlet of the recovery tower is used for recycling the solvent to the solvent inlet of the simulated moving bed, so that the solvent consumption and waste discharge are reduced, the second outlet of the simulated moving bed is used for returning the incompletely separated materials to the separation tower for recycling treatment, the overall separation efficiency and product recovery rate are improved, and resource waste is reduced. BRIEF DESCRIPTION OF DRAWINGS
[0019] The drawings incorporated into the specification and constituting a part of the specification show embodiments consistent with the application and, together with the specification, serve to explain the principles of the application.
[0020] Figure 1 A structure schematic diagram of a nitrile compound refining system provided by the application is provided.
[0021] Figure 2 A structure schematic diagram of another nitrile compound refining system provided by the application is provided.
[0022] Explanation of reference signs:
[0023] 100 - separation tower; 101 - first feed inlet; 102 - tower top outlet; 103 - tower kettle outlet;
[0024] 200 - simulated moving bed; 201 - second feed inlet; 202 - first outlet; 203 - second outlet; 204 - solvent inlet;
[0025] 300 - recovery column; 301 - third feed inlet; 302 - third outlet; 303 - fourth outlet;
[0026] 400 - rectification column; 401 - fourth feed inlet; 402 - fifth outlet; 403 - heavy impurity outlet;
[0027] 500 - recycle line;
[0028] 600 - make-up line;
[0029] 700 - buffer tank.
[0030] The specific embodiments of the application have been shown by way of example in the above figures, and will be described in more detail hereafter. These figures and the written description are not to be understood to limit the scope of the inventive concept in any way, but rather to illustrate the inventive concept by reference to specific embodiments. DETAILED DESCRIPTION
[0031] The exemplary embodiments will be described in detail herein with reference to the attached drawings. The description of the exemplary embodiments is intended to apply to any embodiment of the application, unless specified otherwise. It should be understood that every embodiment need not necessarily include all of the features shown and described herein. The following exemplary embodiments are described with reference to the attached figures.
[0032] In the production process of nitrile compounds, raw materials or intermediate products are often accompanied by the generation of structural similar, close-boiling-point isomer impurities. For example, in the production process of adiponitrile (ADN) and its related compounds, C6 dinitrile isomers such as 2-methylglutaronitrile (2-MGN) and ethylsuccinonitrile (ESN) are generated. These isomers seriously affect the quality of the final product and must be separated.
[0033] In the related art, distillation technology is used for separation, such as gradually separating target products through multiple vacuum rectification column systems connected in series, or crystallization technology is used for separation, such as achieving deep purification through solvent crystallization, for example, using alkanols and other solvents to preferentially crystallize and precipitate target products at low temperatures.
[0034] However, due to the small difference in boiling points of isomer impurities, distillation and crystallization processes need to rely on high-energy consumption equipment or extend the operation time to achieve the target purity, which is high in energy consumption and low in efficiency.
[0035] In addition, adsorption technology is also used for separation, such as mainly used for removing trace impurities or recovering organic matter in tail gas (such as activated carbon adsorption), while crystallization and fixed bed adsorption technology cannot meet the needs of large-scale continuous production, and the efficiency is low.
[0036] In view of the above, the present application provides a nitrile compound refining system and an amine compound preparation system, comprising: a separation column, which is provided with a first feed inlet, a column top outlet and a column bottom outlet; a simulated moving bed, which is provided with a second feed inlet, a first outlet, a second outlet and a solvent inlet, the second feed inlet being communicated with the column top outlet, and the second outlet being communicated with the separation column; a recovery column, which is provided with a third feed inlet, a third outlet and a fourth outlet, the third feed inlet being communicated with the first outlet of the simulated moving bed, the third outlet being communicated with the solvent inlet of the simulated moving bed, and the fourth outlet being used for outputting a first compound; and a rectifying column, which is provided with a fourth feed inlet and a fifth outlet, the fourth feed inlet being communicated with the column bottom outlet of the separation column, and the fifth outlet being used for outputting a second compound.
[0037] The present application integrates the rectification technology and the adsorption separation technology of the simulated moving bed (SMB), adds the simulated moving bed on the basis of the rectifying column, realizes the separation of isomer impurities with similar boiling points, and separates the preliminarily separated materials (such as isomers (ESN) with lower boiling points) into the simulated moving bed for fine separation to remove residual impurity isomers (2-MGN), and obtains a first compound, such as an ESN product with high purity, through the recovery column. The preliminarily separated materials (isomers (2-MGN) with higher boiling points and heavy impurities) are separated into the rectifying column for further purification to obtain a second compound. The second compound can also be 2-MGN. In addition, the third outlet of the recovery column recycles the solvent to the solvent inlet of the simulated moving bed, reduces the solvent consumption and waste discharge, the second outlet of the simulated moving bed returns the incompletely separated materials to the separation column for recycling treatment, improves the overall separation efficiency and product recovery rate, and reduces resource waste.
[0038] The present application will be described below in combination with the drawings and specific embodiments.
[0039] The present application provides a nitrile compound refining system, such as Figure 1As shown, it comprises: a separation column 100, which is provided with a first feed inlet 101, an overhead outlet 102 and a column bottom outlet 103; a simulated moving bed 200, which is provided with a second feed inlet 201, a first outlet 202, a second outlet 203 and a solvent inlet 204, the second feed inlet 201 is communicated with the overhead outlet 102, and the second outlet 203 is communicated with the separation column 100; a recovery column 300, which is provided with a third feed inlet 301, a third outlet 302 and a fourth outlet 303, the third feed inlet 301 is communicated with the first outlet 202 of the simulated moving bed 200, the third outlet 302 is communicated with the solvent inlet 204 of the simulated moving bed 200, and the fourth outlet 303 is used for outputting a first compound; and a rectification column 400, which is provided with a fourth feed inlet 401 and a fifth outlet 402, the fourth feed inlet 401 is communicated with the column bottom outlet 103 of the separation column 100, and the fifth outlet 402 is used for outputting a second compound.
[0040] The present application integrates the rectification technology and the adsorption separation technology of the simulated moving bed 200, preliminarily separates the near-boiling-point isomers (such as 2-methyl glutaronitrile (2-MGN) and ethyl succinonitrile (ESN)) through the separation column 100, and then deeply purifies the key components by using the purification unit of the simulated moving bed 200, so as to realize efficient, low-energy-consumption and continuous separation.
[0041] The present application preliminarily separates the near-boiling-point isomers through the separation column 100, sends the high-purity target components (such as ESN) into the simulated moving bed 200 for deep purification, reduces the impurity load of the feed of the simulated moving bed 200, and improves the overall separation efficiency. The impurities of the simulated moving bed 200 are returned to the raw material inlet of the separation column 100 through the second outlet 203, forming an impurity recycling path, realizing the reprocessing of the unseparated impurities, avoiding material waste, and improving the utilization rate of the feed of the separation column 100.
[0042] The column bottom outlet 103 of the separation column 100 is connected with the rectification column 400, the rectification column 400 is used for separating 2-MGN and heavy impurities in the column bottom material of the separation column 100, recovering high-purity 2-MGN (purity 99.5%) from the column bottom material, and improving the overall material utilization rate and economic benefit of the system. Moreover, the rectification column 400 is suitable for batch separation, the combination of the rectification technology and the adsorption separation technology of the simulated moving bed 200 plays the role of batch separation of the rectification column, realizes large-scale continuous production, and the simulated moving bed 200 performs precise separation and improves the purity.
[0043] The first feed inlet 101 is used for the crude raw material to enter, taking the crude raw material containing 2-methyl glutaronitrile (2-MGN), ethyl succinonitrile (ESN) and high-boiling-point heavy impurities as an example, which is pumped into the middle and lower part of the separation column 100 through the first feed inlet 101.
[0044] The separation column 100 is used for the preliminary batch separation. As the separation column 100 is configured, the relatively low boiling ethyl succinonitrile (ESN) is concentrated as the overhead product, flowing out of the overhead outlet 102, through the overhead material line, into the second feed inlet 201; the slightly higher boiling 2-MGN and significantly higher boiling heavy impurities are trapped in the column sump and discharged from the column sump outlet 103, through the column sump material line, into the fourth feed inlet 401.
[0045] The gas phase or condensed liquid drawn from the overhead outlet 102 of the separation column 100, i.e. the mixture of concentrated ESN and a small amount of residual 2-MGN, flows into the second feed inlet 201 of the simulated moving bed 200 through the overhead material line. In addition, a buffer tank 700 can also be provided on the overhead material line. After pressure and flow stabilization through the buffer tank 700 as necessary, it is fed into the simulated moving bed 200 as feed.
[0046] The feed from the second feed inlet 201 into the simulated moving bed 200 is countercurrently contacted with the desorbent. Since ESN is the main component, the simulated moving bed 200 is used to remove trace amounts of strongly adsorbed impurities (2-MGN in this case) therein. Therefore, high-purity ESN as a weakly adsorbed component (fast component) flows out of the first outlet 202, through the purified product line, into the recovery column 300 through the third feed inlet 301. And the residual 2-MGN as a strongly adsorbed component (slow component) flows out of the second outlet 203, through the impurity outlet line, back to the first feed inlet 101 of the separation column 100, to avoid material loss. Among them, the second outlet 203 is used as an extraction liquid outlet to make the impurities flow out.
[0047] The material flowing out of the first outlet 202 of the simulated moving bed 200, through the third feed inlet 301, into the recovery column 300, is subjected to simple rectification to obtain the final high-purity ESN product, which flows out of the fourth outlet 303, thereby obtaining high-purity ESN. The desorbent recovered from the top of the column is returned to the simulated moving bed 200 through the third outlet 302. Among them, the material flowing out of the first outlet 202 of the simulated moving bed 200, through the third feed inlet 301, into the recovery column 300, includes high-purity ESN and desorbent.
[0048] At the same time, the material rich in 2-MGN and heavy impurities drawn from the column sump outlet 103 of the separation column 100, through the column sump material line, through the fourth feed inlet 401, into the rectification column 400. The task of this rectification column 400 (such as a high-efficiency rectification column 400) is to separate 2-MGN from the final heavy impurities, obtaining high-purity 2-MGN product from the fifth outlet 402 at the top or side of the column. The heavy impurities are discharged from the heavy impurity outlet 403 at the column sump.
[0049] Among them, as Figure 1 and Figure 2As shown, the system further comprises a circulation pipeline 500, one end of the circulation pipeline 500 being in communication with the solvent inlet 204 of the simulated moving bed 200, and the other end of the circulation pipeline 500 being in communication with the third outlet 302 of the recovery column 300. The desorbent recovered from the top of the column passes through the third outlet 302, the circulation pipeline 500, and returns to the simulated moving bed 200 from the solvent inlet 204.
[0050] In order to supplement the system with solvent, as shown in Figure 1 and Figure 2 As shown, the system further comprises a circulation pipeline 500, one end of the circulation pipeline 500 being in communication with the solvent inlet 204 of the simulated moving bed 200, and the other end of the circulation pipeline 500 being in communication with the third outlet 302 of the recovery column 300. The desorbent recovered from the top of the column passes through the third outlet 302, the circulation pipeline 500, and returns to the simulated moving bed 200 from the solvent inlet 204.
[0051] The circulation pipeline 600 is used to supplement the system with fresh solvent, such as adding desorbent to the simulated moving bed 200. In addition, since the desorbent recovered from the recovery column 300 returns to the simulated moving bed 200 from the solvent inlet 204 through the third outlet 302. Therefore, the circulation pipeline 600 can also combine the desorbent from the recovery column 300 with the solvent inlet 204.
[0052] In some embodiments, the simulated moving bed 200 comprises N chromatographic columns filled with adsorbent, N being greater than or equal to 6 and less than or equal to 24. For example, the simulated moving bed 200 comprises 8 chromatographic columns filled with 13X molecular sieve adsorbent.
[0053] The present application combines rectification with the simulated moving bed 200 technology, and effectively solves the problems of high energy consumption and low purity in separating such near-boiling point isomers by traditional methods, by utilizing the synergistic effect of specific adsorbent and desorbent, and has industrial applicability.
[0054] In some embodiments, in the height direction of the simulated moving bed 200, the solvent inlet 204 of the simulated moving bed 200 is located at the bottom end of the simulated moving bed 200, the second feed inlet 201 of the simulated moving bed 200 is higher than the solvent inlet 204, and the material entering from the second feed inlet 201 is countercurrently contacted with the desorbent entering from the solvent inlet 204.
[0055] In the purification unit of the simulated moving bed 200, the feed and the desorbent are countercurrently contacted, the feed entering from the second feed inlet 201 is countercurrently contacted with the desorbent, and since ESN is the main component, the simulated moving bed 200 is used to remove the trace strong adsorption impurities (2-MGN in this example) therein. Therefore, the high-purity ESN, as a weakly adsorbed component (fast component), flows out from the first outlet 202 and enters the recovery column 300. And the residual 2-MGN, as a strongly adsorbed component (slow component), flows out from the second outlet 203 and returns to the feed inlet of the separation column 100, avoiding material loss. The second outlet 203 is used as an extract outlet to make the impurities flow out.
[0056] The material flowing out of the first outlet 202 of the simulated moving bed 200, through the third feed port 301, into the recovery column 300, is subjected to simple distillation to obtain the final high-purity ESN product, which flows out of the fourth outlet 303. The desorbent recovered at the top of the column is returned to the simulated moving bed 200 through the third outlet 302. The material flowing out of the first outlet 202 of the simulated moving bed 200, through the third feed port 301, into the recovery column 300, includes high-purity ESN and desorbent.
[0057] In addition, as shown in Figure 2 The application further includes a buffer tank 700, which is located between the separation column 100 and the simulated moving bed 200, and which is in communication with the overhead outlet 102 of the separation column 100 and the second feed port 201 of the simulated moving bed 200, respectively. The buffer tank 700 is used to stabilize the pressure and flow rate of the gas phase or condensed liquid drawn from the overhead outlet 102 of the separation column 100, i.e., the mixture of the enriched ESN and a small amount of residual 2-MGN, which is sent into the purification unit of the simulated moving bed 200 as feed after being stabilized in pressure and flow rate by the material pipeline and, if necessary, by the buffer tank 700.
[0058] In some embodiments, the second compound has a higher boiling point than the first compound.
[0059] In a specific implementation, the separation column 100 is configured to enrich ESN, which has a relatively low boiling point, as the overhead product, and to make the first compound have a lower boiling point, so that the first compound flows out of the overhead outlet 102; and to retain 2-MGN, which has a slightly higher boiling point, and heavy impurities, which have a significantly higher boiling point, in the column sump, and to make the second compound have a higher boiling point, so that the second compound flows out of the column sump outlet 103, and thus the second compound has a higher boiling point than the first compound.
[0060] In some embodiments, the first compound is ethyl succinonitrile, and the second compound is 2-methylglutaronitrile.
[0061] In addition, the desorbent input through the solvent inlet 204 is toluene or p-diethylbenzene; and / or, the adsorbent in the simulated moving bed 200 is 13X molecular sieve or spherical silica gel modified with a -CN group on the surface.
[0062] It should be noted that the specific combination of 13X molecular sieve adsorbent and toluene desorbent for the separation of the ESN / 2-MGN system exhibits selectivity beyond that of conventional aromatic desorbents (such as p-diethylbenzene), enabling extremely high product purity to be achieved under mild conditions, which is unpredictable for those skilled in the art.
[0063] In some other embodiments, the distillation column 400 is further provided with a heavy impurity outlet 403.
[0064] Specifically, the material rich in 2-MGN and heavy impurities, drawn from the bottom outlet 103 of the separation column 100, enters the distillation column 400 through the fourth feed inlet 401. The task of this column (such as a high-efficiency distillation column 400) is to separate the 2-MGN from the final heavy impurities, obtaining a high-purity 2-MGN product from the fifth outlet 402 at the top or side stream. The heavy impurities are discharged from the heavy impurities outlet 403 at the bottom of the column.
[0065] Experimental Example 1
[0066] In specific implementation, the following methods are adopted: Figure 1 The system shown continuously pumps crude feed into a separation column 100 equipped with 30 theoretical trays. The column top temperature is controlled at 155°C, the column top pressure at 5.0 kPa (absolute pressure), and the reflux ratio at 8:1. A mixture of 80 wt% ethyl succinate (ESN), 18 wt% 2-methylglutaronitrile (2-MGN), and 2 wt% other light impurities (mainly valeronitrile) is obtained from the top of the column.
[0067] The mixture from the top of the column was fed into the purification unit of a simulated moving bed 200 at a flow rate of 10 kg / h. The simulated moving bed 200 contained eight chromatographic columns packed with 13X molecular sieve adsorbent, and the operating temperature was maintained at 130°C. Toluene was used as the desorbent, with the desorbent flow rate set at 15 kg / h, the feed flow rate at 10 kg / h, the extract flow rate at 12 kg / h, and the extract flow rate at 13 kg / h, with a switching time of 60 seconds. After operation, the liquid exiting from the first outlet 202 was processed by a recovery tower 300, and the first compound was output from the fourth outlet 303 of the recovery tower 300, thus obtaining an ESN product with a purity of 99.92% and a yield of 99.1%.
[0068] The bottom material of the separation tower 100 enters the distillation process. After distillation, the fifth outlet 402 is used to output the second compound, thereby obtaining a 2-MGN product with a purity of 99.5%.
[0069] Experiment Example 2
[0070] It should be noted that this embodiment aims to illustrate the adaptability of the present invention under different operating temperatures, and uses the exact same equipment and materials as in Experimental Example 1. The operating conditions of the separation tower 100 remain unchanged. The operating temperature of the purification unit of the simulated moving bed 200 is reduced to 110°C, while other parameters such as flow rate and switching time remain unchanged.
[0071] After stable operation at 110℃, the feed liquid is transferred from the simulated moving bed 200 to the recovery column 300, and the first compound obtained after treatment by the recovery column 300 is ESN product with a purity of 99.86% and a yield of 98.8%. The results show that at a lower temperature, the adsorption selectivity can be slightly improved, but the mass transfer rate can be reduced, and the overall effect can still achieve very high product purity, proving that the present application has a wide temperature operation window.
[0072] Experimental Example 3
[0073] It should be noted that this embodiment is intended to illustrate the applicability of the present application to different types of adsorbents, and the same equipment and materials as in Experimental Example 1 are used. The operating conditions of the separation column 100 remain unchanged. The adsorbent in the purification unit of the simulated moving bed 200 is replaced by spherical silica gel modified with a -CN group on the surface. To adapt to the characteristics of the new adsorbent, the operating temperature of the simulated moving bed 200 is adjusted to 100℃, the switching time is extended to 75 seconds, and the remaining flow rate parameters remain unchanged.
[0074] After stable operation, the first compound is obtained from the fourth outlet 303, i.e. ESN product with a purity of 99.90% and a yield of 99.0%. The results show that by using different types of selective adsorbents and adapting the operating parameters, the system of the present application can also achieve efficient separation, proving the universality of the technical solution of the present application.
[0075] Experimental Example 4
[0076] It should be noted that this embodiment is intended to illustrate the performance of the present application under high processing load, and the same equipment and materials as in Experimental Example 1 are used. The operating conditions of the separation column 100 remain unchanged. To improve the processing efficiency, the feed flow rate into the purification unit of the simulated moving bed 200 is increased by 50% to 15 kg / h. To maintain material balance and separation effect, the other flow rates are scaled up proportionally: the desorbent flow rate is increased to 22.5 kg / h, the draw-off liquid flow rate is increased to 18 kg / h, and the extractant flow rate is increased to 19.5 kg / h. The operating temperature and switching time remain unchanged.
[0077] After stable operation, the first compound is obtained from the fourth outlet 303, i.e. ESN product with a purity of 99.81% and a yield of 98.5%. The results show that after significantly increasing the processing load, the product purity has a slight decrease, but it is still much higher than that of conventional rectification, and the total output per unit time is greatly increased. This proves that the system of the present application not only has high separation precision, but also has excellent industrial scaling potential and operating flexibility.
[0078] Comparative Experimental Example 1, pure rectification process, such as a series system composed of two high-efficiency rectification towers 400. The first tower (equivalent to the separation tower 100) is also operated to obtain the same overhead distillate (containing 80% ESN) as in Experimental Example 1. The overhead distillate (containing 80% ESN) is sent to the second closely rectification tower with 120 theoretical plates, which is operated at a high reflux ratio of 25:1. The final ESN product purity is only 99.2%, and the unit product steam consumption is 3.5 times that of Example 1. The results show that it is difficult to economically obtain high-purity products by pure rectification method, and the energy consumption is huge.
[0079] The utility model rationally allocates the separation task, lets the rectification tower 400 bear its batch separation, and lets the simulated moving bed 200 bear its precision purification. Compared with the pure rectification process, the comprehensive energy consumption of the system is reduced, and the economic benefit is remarkable.
[0080] Comparative Experimental Example 2, the simulated moving bed 200 process using different desorbents, using the same system and operation process as Experimental Example 1 above, only replacing the desorbent of the simulated moving bed 200 with the commonly used p-diethylbenzene in the field. Under the same operating conditions, the final ESN product purity obtained from the recovery tower 300 is only 97.5%. If the purity of 99.9% is to be achieved, the equipment scale of the simulated moving bed 200 needs to be expanded by 50% or the product yield needs to be reduced to below 85%. The results prove that the combination of toluene and 13X molecular sieve has an unexpected synergistic effect and technical advantage in the system of the utility model, which cannot be easily predicted by those skilled in the art.
[0081] The application also includes an amine compound preparation system, which includes the nitrile compound refining system of any one of the above embodiments. The nitrile compound refining system obtains a second compound, such as 2-methylglutaronitrile, and the amine compound preparation system further obtains an amine compound (such as 2-methylglutaramide) using the second compound obtained by the nitrile compound refining system as a raw material. For example, 2-methylglutaramide is prepared from 2-methylglutaronitrile, and the 2-methylglutaronitrile refined by the nitrile compound refining system has higher purity, which can be used to prepare purer 2-methylglutaramide.
[0082] It should be noted that the amine compound preparation system can use a commonly used catalytic hydrogenation process to obtain 2-methylglutaramide from 2-methylglutaronitrile, and under other conditions, only by using the nitrile compound refining system to obtain purer 2-methylglutaronitrile as a raw material, the obtained 2-methylglutaramide is purer.
[0083] It should be understood that many variations can be made in the embodiments described and shown which should be considered within the scope of the present application as defined by the appended claims.
Claims
1. A nitrile compound refining system characterized by comprising: The application relates to a separation system. The separation system comprises: a separation tower (100) provided with a first feed inlet (101), a tower top outlet (102) and a tower bottom outlet (103); a simulated moving bed (200) provided with a second feed inlet (201), a first outlet (202), a second outlet (203) and a solvent inlet (204), the second feed inlet (201) being communicated with the tower top outlet (102), and the second outlet (203) being communicated with the separation tower (100); a recovery tower (300) provided with a third feed inlet (301), a third outlet (302) and a fourth outlet (303), the third feed inlet (301) being communicated with the first outlet (202) of the simulated moving bed (200), the third outlet (302) being communicated with the solvent inlet (204) of the simulated moving bed (200), and the fourth outlet (303) being used for outputting a first compound; 2. The nitrile compound refining system according to claim 1, wherein a rectifying tower (400) provided with a fourth feed inlet (401) and a fifth outlet (402), the fourth feed inlet (401) being communicated with the tower bottom outlet (103) of the separation tower (100), and the fifth outlet (402) being used for outputting a second compound.
3. The nitrile compound refining system according to claim 2, wherein The separation system further comprises a circulating pipeline (500), one end of the circulating pipeline (500) being communicated with the solvent inlet (204) of the simulated moving bed (200), and the other end of the circulating pipeline (500) being communicated with the third outlet (302) of the recovery tower (300).
4. The nitrile compound refining system according to any one of claims 1 to 3, characterized by, The separation system further comprises a supplement pipeline (600), the supplement pipeline (600) being communicated with the solvent inlet (204) of the simulated moving bed (200).
5. The nitrile compound refining system according to any one of claims 1 to 3, wherein The simulated moving bed (200) comprises N chromatographic columns filled with adsorbents, N being greater than or equal to 6 and less than or equal to 24.
6. The nitrile compound refining system according to any one of claims 1 to 3, wherein In the height direction of the simulated moving bed (200), the solvent inlet (204) of the simulated moving bed (200) is located at the bottom end of the simulated moving bed (200), the second feed inlet (201) of the simulated moving bed (200) is higher than the solvent inlet (204), and the material entering the second feed inlet (201) is countercurrently contacted with the desorbent entering the solvent inlet (204).
7. The nitrile compound refining system according to any one of claims 1 to 3, wherein The separation system further comprises a buffer tank (700) located between the separation tower (100) and the simulated moving bed (200), and the buffer tank (700) is communicated with the tower top outlet (102) and the second feed inlet (201) of the simulated moving bed (200) respectively.
8. The nitrile compound refining system according to any one of claims 1 to 3, wherein The boiling point of the second compound is greater than that of the first compound, the first compound is ethyl succinonitrile, and the second compound is 2-methylglutaronitrile. The desorbent input by the solvent inlet (204) is toluene or p-diethylbenzene. And / or, the adsorbent in the simulated moving bed (200) is 13X molecular sieve or spherical silica gel modified by a-CN group.
9. The nitrile compound refining system according to any one of claims 1 to 3, wherein The rectification tower (400) is further provided with a heavy impurity outlet (403).
10. A system for preparing amine compounds, characterized in that, The nitrile compound refining system comprises the rectification tower (400).