Compound rectification system

Abstract

The utility model provides a compound rectification system which comprises a first-stage rectification tower, a second-stage rectification tower and a third-stage rectification tower, a feed port of the first-stage rectification tower is communicated with a crude product tank through a crude product pipeline, and a steam outlet in the top of the first-stage rectification tower is communicated with a steam inlet of a first condenser through a first steam pipeline; the lower section of the second-stage rectifying tower is communicated with a condensate outlet of the first condenser through a first condensing pipeline, the lower section of the second-stage rectifying tower is communicated with the lower section of the first-stage rectifying tower through a material transferring pipeline, and a steam outlet in the top of the second-stage rectifying tower is communicated with a steam inlet of the second condenser through a second steam pipeline; a condensate outlet of the second condenser is communicated with the refined product tank through a second condensation pipeline; a water inlet of the first condenser and a water inlet of the second condenser are communicated with the condensate water storage tank through water inlet pipelines; wherein sulfur layers are arranged on the upper sections of the primary rectifying tower and the secondary rectifying tower. According to the invention, the separation efficiency of thionyl chloride is improved, so that the purity of thionyl chloride obtained by rectification is relatively high.

Description

Technical Field

[0001] The present application relates to the field of distillation technology, and in particular to a compound distillation system. Background Art

[0002] A compound is a pure substance (as distinct from a single substance) composed of two or more different elements. A compound has certain properties, which are different from the elements or ions it contains, and from other compounds, and usually have a certain composition. During the preparation process of a compound, one or more by-products are usually produced, resulting in a low purity of the resulting compound. Therefore, in order to improve the purity of the compound, the resulting crude compound needs to be purified, and distillation is one of the many ways to purify the compound. For example, thionyl chloride is a type of compound. Specifically, thionyl chloride, also known as thionyl chloride, is an inorganic compound with the chemical formula SOCl 2 It is a colorless or yellow odorous liquid with a strong pungent odor. It is miscible with solvents such as benzene, chloroform, and carbon tetrachloride. It is hydrolyzed in water and decomposed by heating. It is mainly used to make acyl chlorides, and is also used in the production of pesticides, medicines, dyes, etc. The sulfur dioxide gas phase synthesis of thionyl chloride uses sulfur dichloride as the raw material. Therefore, a certain amount of sulfur dichloride is contained in the generated crude thionyl chloride. Due to the different volatility of thionyl chloride and sulfur dichloride, a compound distillation system is often used to purify thionyl chloride from the crude thionyl chloride.

[0003] Due to the advantages of simple equipment and easy operation required for single-stage distillation, it is widely used in existing compound distillation systems. That is to say, the existing compound distillation system uses a single-stage distillation method to purify the thionyl chloride in the crude thionyl chloride product, that is, the crude thionyl chloride product is added into a heating kettle, and the heating kettle is heated, so that the volatilized thionyl chloride steam is condensed by a condenser and its condensate is collected. In the above distillation process, the liquid phase and the vapor phase will constantly interact with each other, resulting in the mixing of components, especially in the low-boiling point components, this mixing phenomenon is more obvious. Therefore, the above process makes the separation efficiency of thionyl chloride and sulfur dichloride low, resulting in low purity of the thionyl chloride obtained by distillation. Utility Model Content

[0004] The present application provides a compound distillation system to solve the technical problems described in the above background technology.

[0005] In order to solve the above technical problems, this application adopts the following technical solutions:

[0006] The present application provides a compound distillation system, comprising:

[0007] A primary distillation tower, wherein a feed inlet of the primary distillation tower is connected to a crude product tank via a crude product pipeline, and a steam outlet at the top of the primary distillation tower is connected to a steam inlet of a first condenser via a first steam pipeline;

[0008] A secondary distillation tower, wherein the lower section of the secondary distillation tower is connected to the condensate outlet of the first condenser through a first condensation pipeline, the lower section of the secondary distillation tower is connected to the lower section of the first distillation tower through a material transfer pipeline, the steam outlet at the top of the secondary distillation tower is connected to the steam inlet of the second condenser through a second steam pipeline, the condensate outlet of the second condenser is connected to the fine product tank through a second condensation pipeline, and the water inlet of the first condenser and the water inlet of the second condenser are both connected to the condensate storage tank through a water inlet pipeline;

[0009] Wherein, the upper sections of the primary distillation tower and the secondary distillation tower are both provided with a sulfur layer.

[0010] Optionally, a cooling tower is also included;

[0011] The water inlet of the cooling tower is connected to the water outlet of the first condenser through a first water outlet pipe, the water outlet of the second condenser is connected to the first water outlet pipe through a branch pipe, and the water outlet of the cooling tower is connected to the condensed water storage tank through a second water outlet pipe.

[0012] Optionally, the bottom of the primary distillation tower is connected to a storage tank for storing high-boiling products discharged from the primary distillation tower through a discharge pipeline, and the storage tank is connected to a chlorine pipeline;

[0013] The discharge pipeline is provided with a first flow regulating valve, and the chlorine pipeline is provided with a second flow regulating valve.

[0014] Optionally, heating jackets are provided on the outside of the first distillation tower and the second distillation tower, a first temperature sensor and a second temperature sensor are provided on the side walls near the top and bottom of the first distillation tower, respectively, and a third temperature sensor and a fourth temperature sensor are provided on the sides near the top and bottom of the second distillation tower, respectively.

[0015] Optionally, a plunger metering pump is provided on the crude product pipeline.

[0016] Optionally, a material transfer pump is provided on the material transfer pipeline.

[0017] Optionally, a three-stage distillation tower is also included;

[0018] The lower section of the three-stage distillation tower is connected to one end of the second condensation pipeline away from the condensate outlet of the second condenser, the lower section of the three-stage distillation tower is connected to the lower section of the secondary distillation tower through the material transfer pipeline, the steam outlet at the top of the three-stage distillation tower is connected to the steam inlet of the third condenser through the third steam pipeline, the condensate outlet of the third condenser is connected to the fine product tank through the third condensation pipeline, and the water inlet of the third condenser is connected to the condensate storage tank through the water inlet pipeline;

[0019] Wherein, the sulfur layer is arranged in the upper section of the three-stage distillation tower.

[0020] The compound distillation system provided by the application, the thionyl chloride crude product in the crude product tank is added to a primary distillation tower, the thionyl chloride crude product is under the distillation effect of the primary distillation tower, the steam containing thionyl chloride enters the first condenser and enters the secondary distillation tower through the condensate after the first condenser condenses, the condensate is under the distillation effect of the secondary distillation tower, so that the thionyl chloride in the condensate containing thionyl chloride and other compounds (mainly sulfur dichloride) contained in the thionyl chloride crude product are separated for a second time, the thionyl chloride steam obtained by the secondary distillation enters the second condenser and is condensed by the second condenser, the thionyl chloride condensate after the second condenser condensation is collected by the fine product tank, the separation efficiency of thionyl chloride and other compounds (mainly sulfur dichloride) contained in the thionyl chloride crude product is improved with this, so that the purity of the thionyl chloride obtained by distillation is higher. In addition, the high-boiling substance obtained by rectification in the secondary distillation tower enters the primary distillation tower through its lower section, and the high-boiling substance after the primary distillation and the secondary distillation is recovered by the primary distillation tower, avoiding the waste of raw materials, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 A schematic diagram of the structure of a compound distillation system provided in one embodiment of the present application;

[0023] Figure 2 A schematic diagram of the structure of a compound distillation system provided in another embodiment of the present application;

[0024] Figure 3 A schematic diagram of the structure of a compound distillation system provided in another embodiment of the present application;

[0025] Figure 4A schematic diagram of the structure of a compound distillation system provided in another embodiment of the present application;

[0026] Figure 5 A schematic diagram of the internal structure of a primary distillation tower and a secondary distillation tower provided in one embodiment of the present application.

[0027] In the figure: 100, primary distillation tower; 101, crude product pipeline; 1011, crude product tank; 1012, plunger metering pump; 102, sulfur layer; 103, heating jacket; 104, first temperature sensor; 105, second temperature sensor; 200, first steam pipeline; 201, first condenser; 2011, first condensation pipeline; 300, secondary distillation tower; 301, third temperature sensor; 302, fourth temperature sensor; 400, transfer pipeline; 401, transfer pump; 500, second steam pipeline; 50 1. Second condenser; 5011. Second condensation pipeline; 5012. Fine product tank; 5013. Branch pipe; 600. Water inlet pipeline; 601. Condensate storage tank; 700. Cooling tower; 701. First water outlet pipeline; 702. Second water outlet pipeline; 800. Discharge pipeline; 801. Storage tank; 8011. Chlorine pipeline; 8012. Second flow regulating valve; 802. First flow regulating valve; 900. Three-stage distillation tower; 901. Third steam pipeline; 1000. Third condenser; 1001. Third condensation pipeline. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work also fall within the scope of protection of the present application.

[0029] refer to Figures 1 to 5 , the present application provides a compound distillation system, comprising:

[0030] A primary distillation tower 100, the feed port of the primary distillation tower 100 is connected to the crude product tank 1011 through the crude product pipeline 101, and the steam outlet at the top of the primary distillation tower 100 is connected to the steam inlet of the first condenser 201 through the first steam pipeline 200; wherein, the boiling point of thionyl chloride is 78.8°C; the boiling point of sulfur dichloride is 60°C; sulfur dichloride reacts with sulfur to generate sulfur monochloride, and its boiling point is 137.1°C. The temperature in the bottom of the primary distillation tower is controlled between 110-130°C.

[0031] A secondary distillation tower 300, the lower section of the secondary distillation tower 300 is connected to the condensate outlet of the first condenser 201 through the first condensation pipe 2011, the lower section of the secondary distillation tower 300 is connected to the lower section of the primary distillation tower 100 through the material transfer pipe 400, the steam outlet at the top of the secondary distillation tower 300 is connected to the steam inlet of the second condenser 501 through the second steam pipe 500, the condensate outlet of the second condenser 501 is connected to the fine tank 5012 through the second condensation pipe 5011, and the water inlet of the first condenser 201 and the water inlet of the second condenser 501 are both connected to the condensate storage tank 601 through the water inlet pipe 600; wherein, the temperature in the bottom of the secondary distillation tower 300 is controlled at 70-105°C.

[0032] The upper sections of the primary distillation tower 100 and the secondary distillation tower 300 are both provided with a sulfur layer 102 .

[0033] The compound distillation system provided by the present application, in the process of distilling thionyl chloride, the crude thionyl chloride in the crude product tank 1011 is added to the primary distillation tower 100, the bottom temperature in the primary distillation tower 100 is controlled between 110-130°C, the crude thionyl chloride and sulfur dichloride in the bottom of the tower are converted into steam, and the above-mentioned steam reacts with the sulfur layer 102 in the upper section of the primary distillation tower 100 to be converted into sulfur monochloride during the rising process, and the boiling point of sulfur monochloride (137.1°C) is higher than the temperature in the bottom of the primary distillation tower 100, so the sulfur monochloride refluxes to the bottom of the primary distillation tower 100, and the thionyl chloride steam and the sulfur dichloride steam that is not completely converted into sulfur monochloride enter the first condenser 201 through the steam outlet at the top of the primary distillation tower 100, the first steam pipeline 200 and the steam inlet of the first condenser 201, and the condensate after condensation by the first condenser 201 is condensed by the first condenser 201. The condensate outlet and the first condensation pipe 2011 enter the secondary distillation tower 300, and the temperature in the bottom of the secondary distillation tower 300 is controlled at 70-105°C. The thionyl chloride condensate and the sulfur dichloride condensate entering the secondary distillation tower 300 are converted into thionyl chloride vapor and sulfur dichloride vapor again. In the process of the above-mentioned steam diffusing to the upper section of the secondary distillation tower 300, the sulfur dichloride vapor reacts with the sulfur layer 102 in the upper section of the secondary distillation tower 300 and is converted into sulfur monochloride and refluxes to the bottom of the secondary distillation tower 300, and the thionyl chloride vapor enters the second condenser 501 through the steam outlet at the top of the secondary distillation tower 300, the second steam pipe 500 and the steam inlet of the second condenser 501. The condensate condensed by the second condenser 501 enters the fine product tank 5012 through the condensate outlet of the second condenser 501 and the second condensation pipe 5011, and the thionyl chloride after the secondary distillation is stored in the fine product tank 5012. The present application removes impurities in thionyl chloride step by step through the primary distillation tower 100 and the secondary distillation tower 300, thereby improving the separation efficiency of thionyl chloride and other compounds (mainly sulfur dichloride) contained in the crude thionyl chloride product, so that the purity of the thionyl chloride obtained by distillation is higher. In addition, the high boiling products obtained by distillation in the secondary distillation tower 300 enter the primary distillation tower 100 through its lower section, and the high boiling products after the primary distillation and the secondary distillation are recovered by the primary distillation tower 100 to avoid the waste of raw materials, etc.

[0034] It is particularly noted that the present application is only an example of the distillation of thionyl chloride in a compound. In addition, the present application can also be used for the distillation of other compounds with similar chemical properties to thionyl chloride, such as acyl chlorides.

[0035] In some embodiments, reference Figure 2The compound distillation system in the present application also includes a cooling tower 700; specifically, the water inlet of the cooling tower 700 is connected to the water outlet of the first condenser 201 through a first water outlet pipe 701, the water outlet of the second condenser 501 is connected to the first water outlet pipe 701 through a branch pipe 5013, and the water outlet of the cooling tower 700 is connected to the condensed water storage tank 601 through a second water outlet pipe 702.

[0036] In the above embodiment, the condensed water required for condensing thionyl chloride vapor and sulfur dichloride vapor is provided to the first condenser 201 and the second condenser 501 through the condensed water storage tank 601. After the condensed water exchanges heat with the above-mentioned steam (thionyl chloride vapor and sulfur dichloride vapor), the temperature of the condensed water increases. The water with increased temperature in the first condenser 201 enters the cooling tower 700 through the water outlet of the first condenser 201 and the first water outlet pipe 701, while the water with increased temperature in the second condenser 501 enters the cooling tower 700 through the water outlet of the second condenser 501, the branch pipe 5013 and the first water outlet pipe 701. The cooling tower 700 cools the water entering it, and the cooled water is supplied to the condensed water storage tank 601 again, thereby realizing the recycling of condensed water and saving water resources.

[0037] In some embodiments, reference Figure 3 The bottom of the primary distillation tower 100 in the present application is connected to a storage tank 801 for storing high-boiling products discharged from the primary distillation tower 100 through a discharge pipe 800, and a chlorine pipe 8011 is connected to the storage tank 801; wherein, the high-boiling products in the primary distillation tower 100 are mainly sulfur monochloride generated by the reaction of sulfur dichloride and sulfur, and the high-boiling products in the primary distillation tower 100 enter the storage tank 801 through the discharge pipe 800, and chlorine flows into the storage tank 801 through the chlorine pipe 8011, and sulfur monochloride and chlorine react in the storage tank 801 to generate sulfur dichloride (raw material for preparing thionyl chloride).

[0038] A first flow regulating valve 802 is provided on the discharge pipe 800, and a second flow regulating valve 8012 is provided on the chlorine pipe 8011. The amount of sulfur monochloride entering the storage tank 801 is regulated by the first flow regulating valve 802, and the amount of chlorine entering the storage tank 801 is regulated by the second flow regulating valve 8012, so that sulfur monochloride and chlorine react in equal proportions, and then the storage tank 801 contains as much sulfur dichloride as possible generated by the reaction of sulfur monochloride and chlorine, and other by-products, sulfur monochloride, chlorine, etc. are prevented from being stored in the storage tank 801, thereby improving the purity of sulfur dichloride in the storage tank 801.

[0039] In some embodiments, reference Figure 5In the present application, a heating jacket 103 is disposed on the outside of the primary distillation tower 100 and the secondary distillation tower 300, a first temperature sensor 104 and a second temperature sensor 105 are disposed on the side walls near the top and the bottom of the primary distillation tower 100, respectively, and a third temperature sensor 301 and a fourth temperature sensor 302 are disposed on the sides near the top and the bottom of the secondary distillation tower 300, respectively.

[0040] In the above embodiment, in order to improve the purity of thionyl chloride after step-by-step distillation by the primary distillation tower 100 and the secondary distillation tower 300, it is necessary to accurately control the temperature in the primary distillation tower 100 and the secondary distillation tower 300, and the primary distillation tower 100 is heated by the heating jacket 103, and the temperatures of the upper section and the lower section in the primary distillation tower 100 are respectively detected in real time by the first temperature sensor 104 and the second temperature sensor 105, so as to accurately grasp the temperature in the primary distillation tower 100. In addition, while the secondary distillation tower 300 is heated by the heating jacket 103, the temperatures of the upper section and the lower section in the secondary distillation tower 300 are respectively detected in real time by the third temperature sensor 301 and the fourth temperature sensor 302, so as to accurately grasp the temperature in the secondary distillation tower 300. That is to say, the present application improves the distillation efficiency of thionyl chloride by accurately controlling the heating temperature in the primary distillation tower 100 and the secondary distillation tower 300, so as to effectively separate the impurities in the thionyl chloride crude product.

[0041] In some embodiments, reference Figures 1 to 4 In the present application, a plunger metering pump 1012 is provided on the crude product pipeline 101. On the one hand, the plunger metering pump 1012 provides the power for the crude thionyl chloride to enter the crude product tank 1011 through the crude product pipeline 101; on the other hand, the plunger metering pump 1012 can measure the amount of the crude thionyl chloride delivered to the crude product tank 1011, so as to calculate the distillation efficiency of the thionyl chloride according to the amount of the thionyl chloride obtained after distillation.

[0042] In some embodiments, reference Figures 1 to 4 The transfer pipe 400 in the present application is provided with a transfer pump 401. The high-boiling substances at the bottom of the secondary distillation tower 300 are pumped into the primary distillation tower 100 through the transfer pipe 400 by the transfer pump 401, ensuring that the high-boiling substances in the secondary distillation tower 300 enter the primary distillation tower 100 as much as possible.

[0043] In some embodiments, reference Figure 4The compound distillation system in the present application also includes a three-stage distillation tower 900; specifically, the lower section of the three-stage distillation tower 900 is connected to one end of the second condensation pipe 5011 away from the condensate outlet of the second condenser 501, the lower section of the three-stage distillation tower 900 is connected to the lower section of the two-stage distillation tower 300 through the transfer pipe 400, the steam outlet at the top of the three-stage distillation tower 900 is connected to the steam inlet of the third condenser 1000 through the third steam pipe 901, the condensate outlet of the third condenser 1000 is connected to the fine tank 5012 through the third condensation pipe 1001, and the water inlet of the third condenser 1000 is connected to the condensate storage tank 601 through the water inlet pipe 600; wherein, the bottom temperature in the three-stage distillation tower 900 is 78-80°C, which is closer to the boiling point of thionyl chloride.

[0044] The upper section of the three-stage distillation tower 900 is provided with a sulfur layer 102. The condensate condensed by the second condenser 501 enters the three-stage distillation tower 900 through the condensate outlet of the second condenser 501 and the second condensation pipeline 5011, and is converted into steam under the temperature in the three-stage distillation tower 900. The sulfur dichloride vapor contained in the steam reacts with the sulfur layer 102 in the upper section of the three-stage distillation tower 900 and is converted into sulfur monochloride and refluxes to the bottom of the three-stage distillation tower 900, while the remaining thionyl chloride vapor enters the fine product tank 5012 through the steam outlet on the three-stage distillation tower 900 and the third steam pipeline 901. The thionyl chloride after the three-stage distillation is collected by the fine product tank 5012, and the three-stage distillation further improves the purity of the thionyl chloride after distillation.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A compound distillation system, characterized in that: include: A primary distillation tower (100), wherein a feed inlet of the primary distillation tower (100) is connected to a crude product tank (1011) via a crude product pipeline (101), and a steam outlet at the top of the primary distillation tower (100) is connected to a steam inlet of a first condenser (201) via a first steam pipeline (200); A secondary distillation tower (300), wherein the lower section of the secondary distillation tower (300) is connected to the condensate outlet of the first condenser (201) via a first condensation pipeline (2011), the lower section of the secondary distillation tower (300) is connected to the lower section of the first distillation tower (100) via a material transfer pipeline (400), the steam outlet at the top of the secondary distillation tower (300) is connected to the steam inlet of the second condenser (501) via a second steam pipeline (500), the condensate outlet of the second condenser (501) is connected to the fine product tank (5012) via a second condensation pipeline (5011), and the water inlet of the first condenser (201) and the water inlet of the second condenser (501) are both connected to the condensate storage tank (601) via a water inlet pipeline (600); Wherein, the upper sections of the primary distillation tower (100) and the secondary distillation tower (300) are both provided with a sulfur layer (102).

2. The compound distillation system according to claim 1, characterized in that: Also includes a cooling tower (700); The water inlet of the cooling tower (700) is connected to the water outlet of the first condenser (201) through a first water outlet pipe (701), the water outlet of the second condenser (501) is connected to the first water outlet pipe (701) through a branch pipe (5013), and the water outlet of the cooling tower (700) is connected to the condensed water storage tank (601) through a second water outlet pipe (702).

3. The compound distillation system according to claim 1, characterized in that: The bottom of the primary distillation tower (100) is connected to a storage tank (801) for storing high-boiling products discharged from the primary distillation tower (100) through a discharge pipe (800), and the storage tank (801) is connected to a chlorine gas pipe (8011); The discharge pipeline (800) is provided with a first flow regulating valve (802), and the chlorine pipeline (8011) is provided with a second flow regulating valve (8012).

4. The compound distillation system according to claim 1, characterized in that: The first distillation tower (100) and the second distillation tower (300) are both provided with a heating jacket (103) on the outside, the first distillation tower (100) is provided with a first temperature sensor (104) and a second temperature sensor (105) on the side walls near the top and the bottom thereof, respectively, and the second distillation tower (300) is provided with a third temperature sensor (301) and a fourth temperature sensor (302) on the side walls near the top and the bottom thereof, respectively.

5. The compound distillation system according to claim 1, characterized in that: The crude product pipeline (101) is provided with a plunger-type metering pump (1012).

6. The compound distillation system according to claim 1, characterized in that: The material transfer pipeline (400) is provided with a material transfer pump (401).

7. The compound distillation system according to any one of claims 1 to 6, characterized in that: Also includes a three-stage distillation tower (900); The lower section of the three-stage distillation tower (900) is connected to one end of the second condensation pipeline (5011) away from the condensate outlet of the second condenser (501), the lower section of the three-stage distillation tower (900) is connected to the lower section of the two-stage distillation tower (300) through the material transfer pipeline (400), the steam outlet at the top of the three-stage distillation tower (900) is connected to the steam inlet of the third condenser (1000) through the third steam pipeline (901), the condensate outlet of the third condenser (1000) is connected to the fine product tank (5012) through the third condensation pipeline (1001), and the water inlet of the third condenser (1000) is connected to the condensate storage tank (601) through the water inlet pipeline (600); Wherein, the sulfur layer (102) is provided at the upper section of the three-stage distillation tower (900).

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