Device for secondary sulfur distribution of thionyl chloride rectification system

Abstract

The utility model provides a device of secondary sulfur distribution of thionyl chloride rectification system, include: sulfur distribution tank, rectifying column, two shunt settings'supplement sulfur tank, thionyl chloride conveying unit and liquid sulfur supply unit, the crude product thionyl chloride of synthetic procedure output is connected with the inlet of sulfur distribution tank, the outlet of sulfur distribution tank is connected with the inlet of rectifying column, the top outlet of rectifying column is connected with the material inlet of two supplement sulfur tanks respectively through thionyl chloride conveying unit, the liquid sulfur supply unit's outlet is connected with the liquid sulfur inlet of two supplement sulfur tanks respectively, and the discharge port of supplement sulfur tank is used for outputting secondary sulfur distribution thionyl chloride, adopt liquid sulfur supply unit, make liquid sulfur replace traditional solid sulfur, solve the technical problem that solid sulfur is easy to block pipeline and rectifying column, set up the supplement sulfur tank system of shunt, realize the continuous discharge of supplement sulfur tank through intermittent operation, carry out the depth conversion of the unreacted sulfur dichloride in the preposition procedure, improve the purity of subsequent rectification thionyl chloride product.

Description

Technical Field

[0001] This utility model belongs to the field of fine chemical production technology, specifically relating to a device for secondary sulfur preparation in a thionyl chloride distillation system. Background Technology

[0002] Thionyl chloride (SOCl2) is a colorless or pale yellow transparent liquid with a strong, pungent odor. It is soluble in benzene, chloroform, and carbon tetrachloride. In water, it decomposes to produce sulfurous acid and hydrogen chloride gas. When heated to 140°C, it decomposes to produce chlorine gas, sulfur dioxide, and sulfur monochloride. The chlorine atom of thionyl chloride has a strong ability to substitute for hydroxyl and mercapto groups, and sometimes it can also substitute for sulfur dioxide, oxygen, or hydrogen. It can react with organic compounds containing hydroxyl groups, such as phenols or alcohols, to form the corresponding chlorides. It reacts with sulfonic acids to form sulfonyl chlorides, and with Grignard reagents to form the corresponding sulfoxide compounds. It is mainly used in the production of dyes, pharmaceutical intermediates, food additives, and novel lithium salts (LiFSI).

[0003] Currently, the main technologies for producing thionyl chloride in my country include the chlorosulfonic acid method, the co-production method, the sulfur dioxide gas-phase method, and the sulfur trioxide gas-phase method. Among these, the sulfur dioxide gas-phase method is the most advanced, producing colorless and transparent products with virtually no waste generated during the production process, resulting in high product stability.

[0004] The sulfur dioxide gas-phase method mainly uses sulfur, sulfur dioxide, and chlorine as raw materials. The reaction temperature is ≥180℃. Under the action of a catalyst, crude thionyl chloride is generated. The reacted material is then purified by distillation to obtain the final product.

[0005] The gas-phase production process of sulfur dioxide involves multiple reactions, mainly as follows:

[0006] Overall reaction: S + 2Cl₂ + SO₂ = 2SOCl₂

[0007] Sulfur dichloride reactor: Cl₂ + S₂Cl₂ = 2SCl₂, Cl₂ + 2S = S₂Cl₂

[0008] The main reaction in the thionyl chloride synthesis reactor is: 2Cl₂ + SO₂ + SCl₂ = 2SOCl₂

[0009] Side reaction: Cl2 + SO2 = SO2Cl2

[0010] The main reaction for sulfur synthesis is: S + SCl2 = S2Cl2

[0011] In the production of thionyl chloride, the mixed gas from the thionyl chloride synthesis reactor is condensed to form crude thionyl chloride, the main components of which are crude thionyl chloride, sulfur monochloride (S2Cl2) and sulfur dichloride (SCl2). Since the boiling points of sulfur dichloride and thionyl chloride are similar, it is difficult to separate thionyl chloride by distillation. In order to facilitate the separation and purification of thionyl chloride, it is necessary to react the light component sulfur dichloride into the heavy component sulfur monochloride by adding sulfur in the distillation process. The boiling points of sulfur monochloride and thionyl chloride are significantly different, making them easy to separate by distillation.

[0012] The commonly used method for sulfur preparation is to pass crude thionyl chloride into the sulfur preparation vessel and then add sulfur into the vessel. In actual production, secondary sulfur preparation is usually required, but traditional secondary sulfur preparation has three major technical defects: (1) Sulfur is added intermittently to the sulfur-passing section at the top of the distillation column, which results in a large workload and high labor intensity for personnel, and the process of adding sulfur disrupts the balance inside the distillation column; (2) The reaction and blockage of the sulfur-passing section of the distillation column need to be observed regularly, and the accumulated material needs to be cleaned manually to prevent sulfur accumulation; (3) The product after secondary sulfur preparation contains a small amount of unreacted sulfur dichloride, which affects the product quality. Utility Model Content

[0013] This invention provides a device for secondary sulfur preparation in a thionyl chloride distillation system, which solves the problem that the products of the thionyl chloride sulfur preparation system in the prior art contain a small amount of incompletely reacted sulfur dichloride.

[0014] This utility model provides a device for secondary sulfur preparation in a thionyl chloride distillation system, comprising: a sulfur preparation tank, a distillation column, two parallel sulfur replenishment tanks, a thionyl chloride conveying unit, and a liquid sulfur supply unit;

[0015] The crude thionyl chloride output from the synthesis process is connected to the inlet of the sulfur mixing tank, the outlet of the sulfur mixing tank is connected to the inlet of the distillation column, the top outlet of the distillation column is connected to the material inlet of the two sulfur replenishment tanks through the thionyl chloride conveying unit, the outlet of the liquid sulfur supply unit is connected to the liquid sulfur inlet of the two sulfur replenishment tanks, and the outlet of the sulfur replenishment tank is used to output secondary sulfur-mixed thionyl chloride.

[0016] Compared with the prior art, the advantages of this utility model are as follows: It adopts a liquid sulfur supply unit, replacing traditional solid sulfur with liquid sulfur. Utilizing the good fluidity and reactivity of liquid sulfur, it completely solves the technical problem of solid sulfur easily clogging pipes and distillation columns, thus improving the conversion rate of sulfur dichloride. Furthermore, it sets up a parallel sulfur replenishment tank system, achieving continuous discharge from the replenishment tanks through intermittent operation. This allows for the deep conversion of incompletely reacted sulfur dichloride from the pre-treatment sulfur preparation process, significantly improving the purity of the subsequent distilled thionyl chloride product.

[0017] Furthermore, the crude thionyl chloride conveying unit includes a first pump, a first flow meter, a level regulating valve, and a shut-off valve group connected in sequence. The shut-off valve group includes two first shut-off valves connected in parallel, which correspond to the material inlets of the two sulfur replenishment tanks, respectively.

[0018] Furthermore, the liquid sulfur supply unit includes a liquid sulfur storage tank, an external steam coil, and an external thermal insulation material. The steam coil and the thermal insulation material are used to heat and keep the liquid sulfur inside the liquid sulfur storage tank.

[0019] Furthermore, the liquid sulfur supply unit also includes a segmented jacketed pipe, a third pump, a second flow meter, and a second shut-off valve. The third pump, the second flow meter, and the second shut-off valve are installed on the segmented jacketed pipe. The outlet of the liquid sulfur storage tank is connected to the liquid sulfur inlets of the two sulfur replenishment tanks through the segmented jacketed pipe.

[0020] Furthermore, the segmented jacketed pipe includes 15-20 independent heat tracing units, each with a length of 4-6 meters, and the segments are connected by flanges.

[0021] Furthermore, it also includes a second pump, the outlet of the sulfur replenishment tank is connected to the inlet of the second pump, the outlet of the second pump is connected to the return port of the sulfur replenishment tank, and the outlet of the second pump is also used to output the secondary sulfur-containing thionyl chloride.

[0022] Furthermore, a first sight glass is installed on the material inlet pipe of the sulfur replenishment tank to observe the color of the material after distillation, and the second shut-off valve in the liquid sulfur supply unit is controlled according to its color.

[0023] Furthermore, a second sight glass is installed on the pipe connecting the outlet of the second pump to the reflux port of the sulfur replenishment tank, which is used to observe the color of the material after secondary sulfur blending and to control the reflux ratio of the sulfur replenishment tank according to its color.

[0024] Furthermore, a sealed sampling port is installed on the pipeline at the outlet of the sulfur replenishment tank for collecting samples of secondary sulfur-containing thionyl chloride. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the secondary sulfur preparation device in a thionyl chloride distillation system according to one embodiment of the present invention.

[0026] Explanation of reference numerals in the attached figures:

[0027] 1. Sulfur mixing tank; 2. Distillation column; 3. Thionyl chloride conveying unit; 4. Sulfur replenishment tank; 5. Liquid sulfur supply unit; 31. First pump; 32. First flow meter; 33. Liquid level regulating valve; 34. First shut-off valve; 41. Second pump; 42. First sight glass; 42. Second sight glass; 51. Liquid sulfur storage tank; 52. Segmented jacketed pipe; 53. Third pump; 54. Second flow meter; 55. Second shut-off valve; 6. Sealed sampling port. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions in the embodiments of this utility model will be clearly and completely described below in conjunction with the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0029] Please see Figure 1 This utility model provides a device for secondary sulfur preparation in a thionyl chloride distillation system, characterized in that it includes: a sulfur preparation tank 1, a distillation column 2, two parallel sulfur replenishment tanks 4, and a liquid sulfur supply unit 5;

[0030] The crude thionyl chloride output from the synthesis process is connected to the inlet of the sulfur mixing tank 1. The outlet of the sulfur mixing tank 1 is connected to the inlet of the distillation column 2. The top outlet of the distillation column 2 is connected to the material inlets of the two sulfur replenishment tanks 4 through the thionyl chloride conveying unit 3. The outlet of the liquid sulfur supply unit 5 is connected to the liquid sulfur inlets of the two sulfur replenishment tanks 4. The outlet of the sulfur replenishment tank 4 is used to output secondary sulfur-mixed thionyl chloride.

[0031] The device for secondary sulfur preparation in the thionyl chloride distillation system provided by this utility model adopts a liquid sulfur supply unit, which replaces the traditional solid sulfur with liquid sulfur. By utilizing the good fluidity and reactivity of liquid sulfur, the technical problem of solid sulfur easily clogging pipes and distillation columns is completely solved, and the conversion rate of sulfur dichloride is improved. A parallel sulfur replenishment tank system is set up, and the sulfur replenishment tank is continuously discharged through intermittent operation, which deeply converts the sulfur dichloride that has not been fully reacted in the previous sulfur preparation process, and significantly improves the purity of the subsequent distilled thionyl chloride product.

[0032] The crude thionyl chloride feedstock output from the synthesis process comprises 65-75% thionyl chloride, 13-17% sulfur dichloride, 3-7% sulfur monochloride, 3-7% sulfur dioxide, and a small amount of chlorine. The primary thionyl chloride feedstock output from the outlet of sulfur mixing tank 1 comprises 62-72% thionyl chloride, 2-6% sulfur dichloride, 18-22% sulfur monochloride, 3-6% sulfur dioxide, and a small amount of sulfur and chlorine. The distilled thionyl chloride feedstock output from the top outlet of distillation column 2 comprises 85-90% thionyl chloride, 5-7% sulfur dichloride, and a small amount of chlorine and sulfur dioxide. The feedstock output from the bottom outlet of distillation column 2 comprises 93-98% sulfur monochloride, 1-3% sulfur, and a small amount of thionyl chloride. The secondary thionyl chloride feedstock output from the outlet of sulfur replenishment tank 4 comprises 80-90% thionyl chloride, 4-8% sulfur monochloride, and a small amount of chlorine and sulfur dioxide. The material output from the bottom outlet of distillation column 2 is output as sulfur monochloride product and sent to the synthesis process.

[0033] Furthermore, the crude thionyl chloride conveying unit 3 includes a first pump 31, a first flow meter 32, a liquid level regulating valve 33 and a shut-off valve group connected in sequence. The shut-off valve group includes two first shut-off valves 34 connected in parallel, which correspond to the material inlets of the two sulfur replenishment tanks 4 respectively.

[0034] By setting up the first pump 31 to ensure the stable delivery of crude thionyl chloride, the first flow meter 32 to achieve accurate measurement, the liquid level regulating valve 33 to automatically control the liquid level in the sulfur replenishment tank 4, and the two parallel first shut-off valves 34 to achieve flexible switching between the two sulfur replenishment tanks 4, the continuity of production is guaranteed, which further improves production efficiency and ensures the accuracy of process control.

[0035] Optionally, the liquid sulfur supply unit 5 includes a liquid sulfur storage tank 51, with a steam coil on the outside of the liquid sulfur storage tank 51 and thermal insulation material on the outside of the steam coil. The steam coil and thermal insulation material are used to heat and keep the liquid sulfur in the liquid sulfur storage tank 51.

[0036] Through the dual design of steam coils and thermal insulation materials, the sulfur temperature within the liquid sulfur storage tank 51 can be precisely controlled, further ensuring the fluidity of the sulfur and avoiding the impact of temperature fluctuations on the reaction effect, while significantly reducing heat loss. Optionally, the liquid sulfur temperature is 135-145℃, and the flow rate is controlled at 20-30 kg / h.

[0037] Furthermore, the liquid sulfur supply unit 5 also includes a segmented jacketed pipe 52, a third pump 53, a second flow meter 54, and a second shut-off valve 55. The third pump 53, the second flow meter 54, and the second shut-off valve 55 are installed on the segmented jacketed pipe 52. The outlet of the liquid sulfur storage tank 51 is connected to the liquid sulfur inlet of the two sulfur replenishment tanks 4 through the segmented jacketed pipe 52.

[0038] The segmented jacketed pipe 52 is used to transport liquid sulfur. With the help of the third pump 53, the second flow meter 54 and the second shut-off valve 55, the precise metering and temperature-controlled transportation of liquid sulfur are realized. This further ensures that the sulfur maintains the optimal reaction temperature during transportation, while also facilitating system maintenance and repair.

[0039] Specifically, the segmented jacketed pipe 52 includes 15-20 independent heat tracing units, each with a length of 4-6 meters, and the segments are connected by flanges; this further ensures that the sulfur maintains the optimal reaction temperature during transportation. Steam is introduced into the jacketed pipe for heat tracing, and the outside of the jacketed pipe is equipped with thermal insulation material. The steam temperature is 150~160℃.

[0040] In one specific embodiment, a second pump 41 is also included. The outlet of the sulfur replenishment tank 4 is connected to the inlet of the second pump 41, and the outlet of the second pump 41 is connected to the return port of the sulfur replenishment tank 4. The outlet of the second pump 41 is also used to output the secondary sulfur-containing thionyl chloride.

[0041] The material is circulated via a second pump 41, further improving the product reaction efficiency and preventing liquid sulfur deposition. After the reaction, the material is pumped back to a subsequent distillation column via the second pump 41 for further purification of thionyl chloride. Specifically, the reflux ratio is controlled at 20-25%.

[0042] A first sight glass 42 is installed on the material inlet pipe of the sulfur replenishment tank 4 to observe the color of the material after distillation. The opening and closing of the second shut-off valve 55 in the liquid sulfur supply unit 5 is controlled according to the color. It is understood that the thionyl chloride material after the first sulfur preparation and distillation contains a large amount of sulfur dichloride, and the material is reddish-brown. By setting the first sight glass 42, the amount of liquid sulfur added can be judged according to the degree of redness of the material.

[0043] A second sight glass 42 is installed on the pipe connecting the outlet of the second pump 41 to the reflux port of the sulfur replenishment tank 4. This sight glass is used to observe the color of the material after secondary sulfur blending and to control the reflux ratio of the sulfur replenishment tank 4 based on the color. Similarly, after secondary sulfur blending, sulfur dichloride in the material is converted into sulfur monochloride, and the material changes from red to pale yellow. Operators can adjust the reflux ratio and optimize the reaction conditions based on the color change of the reaction products to ensure the complete conversion of sulfur dichloride and improve the quality stability of the final product.

[0044] A sealed sampling port 6 is installed on the pipeline at the outlet of the sulfur replenishment tank 4 for collecting secondary sulfur-containing thionyl chloride samples.

[0045] Furthermore, it also includes a DCS control system, which includes: a PID control module interlocked with the first flow meter 32 and the second flow meter 54; a liquid level control module communicatively connected to the liquid level regulating valve 33; and a time-based switching module for the sulfur replenishment tank 4.

[0046] The integrated PID control module can dynamically adjust the ratio of materials and liquid sulfur based on real-time data from the first flow meter 32 and the second flow meter 54, ensuring that the reaction process is always in the optimal state. The liquid level control module achieves automatic and stable control of the liquid level in the sulfur replenishment tank 4 through linkage with the liquid level regulating valve 33, avoiding the uncertainty of manual adjustment. The time-controlled sulfur replenishment tank 4 switching module realizes the intelligent rotation operation of the two parallel sulfur replenishment tanks 4, which not only ensures production continuity but also extends the service life of the equipment.

[0047] Specifically, the temperature of the distilled thionyl chloride material output from the top outlet of distillation column 2 is 60-80℃, the liquid level of the sulfur replenishment tank 4 is controlled at 60-70%, and the liquid level of distillation column 2 is controlled at 50%-80% by the liquid level regulating valve 33. The first shut-off valve 34 controls the crude thionyl chloride to enter the two sulfur replenishment tanks 4 of distillation column 2 respectively for intermittent operation, thereby improving the product reaction efficiency.

[0048] In one specific embodiment, liquid sulfur in the liquid sulfur storage tank 51 is pumped into the sulfur replenishment tank 4 via a third pump 53, a jacketed pipeline, a second flow meter 54, and a shut-off valve. The flow rate is controlled at 20-30 kg / h. The steam temperature introduced into the jacketed pipeline is 150-160℃. Care is taken to prevent steam condensation and water leakage from the jacketed pipeline to avoid uneven steam distribution, which could cause sulfur crystallization and blockage of the pipeline. Crude thionyl chloride enters the distillation column 2 and flows from the bottom of the column through a first pump 31, a first flow meter 32, a level regulating valve 33, and a first shut-off valve 34 into the sulfur replenishment tank 4. The level of the distillation column 2 is cascaded with the level regulating valve 33 to automatically control the level and flow rate of the distillation column 2. The sulfur replenishment tank 4 operates intermittently. When the second pump 41 at the bottom of the sulfur replenishment tank 4 is started, the reaction begins to circulate. After the reaction is completed, the sulfur is sent to the subsequent distillation system for distillation separation.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. If these modifications and variations fall within the scope of the claims of this utility model and their equivalents, they should be considered to be within the protection scope of this utility model.

Claims

1. A device for secondary sulfur preparation in a thionyl chloride distillation system, characterized in that, include: The system includes a sulfur mixing tank, a distillation column, two parallel sulfur replenishment tanks, a thionyl chloride conveying unit, and a liquid sulfur supply unit. The crude thionyl chloride output from the synthesis process is connected to the inlet of the sulfur mixing tank, the outlet of the sulfur mixing tank is connected to the inlet of the distillation column, the top outlet of the distillation column is connected to the material inlet of the two sulfur replenishment tanks through the thionyl chloride conveying unit, the outlet of the liquid sulfur supply unit is connected to the liquid sulfur inlet of the two sulfur replenishment tanks, and the outlet of the sulfur replenishment tank is used to output secondary sulfur-mixed thionyl chloride.

2. The apparatus for secondary sulfur preparation in the thionyl chloride distillation system according to claim 1, characterized in that, The crude thionyl chloride conveying unit includes a first pump, a first flow meter, a level regulating valve, and a shut-off valve group connected in sequence. The shut-off valve group includes two first shut-off valves connected in parallel, which correspond to the material inlets of the two sulfur replenishment tanks, respectively.

3. The apparatus for secondary sulfur preparation in the thionyl chloride distillation system according to claim 2, characterized in that, The liquid sulfur supply unit includes a liquid sulfur storage tank, an external steam coil, and an external thermal insulation material. The steam coil and thermal insulation material are used to heat and keep the liquid sulfur in the liquid sulfur storage tank.

4. The apparatus for secondary sulfur preparation in the thionyl chloride distillation system according to claim 3, characterized in that, The liquid sulfur supply unit also includes a segmented jacketed pipe, a third pump, a second flow meter, and a second shut-off valve. The third pump, the second flow meter, and the second shut-off valve are installed on the segmented jacketed pipe. The outlet of the liquid sulfur storage tank is connected to the liquid sulfur inlet of the two sulfur replenishment tanks through the segmented jacketed pipe.

5. The apparatus for secondary sulfur preparation in the thionyl chloride distillation system according to claim 4, characterized in that, The segmented jacketed pipe consists of 15-20 independent heat tracing units, each with a length of 4-6 meters, and the segments are connected by flanges.

6. The apparatus for secondary sulfur preparation in the thionyl chloride distillation system according to claim 5, characterized in that, It also includes a second pump, the outlet of the sulfur replenishment tank is connected to the inlet of the second pump, the outlet of the second pump is connected to the return port of the sulfur replenishment tank, and the outlet of the second pump is also used to output the secondary sulfur-containing thionyl chloride.

7. The apparatus for secondary sulfur preparation in the thionyl chloride distillation system according to claim 6, characterized in that, A first sight glass is installed on the material inlet pipe of the sulfur replenishment tank to observe the color of the material after distillation, and the second shut-off valve in the liquid sulfur supply unit is controlled according to its color.

8. The apparatus for secondary sulfur preparation in the thionyl chloride distillation system according to claim 7, characterized in that, A second sight glass is installed on the pipe connecting the outlet of the second pump to the reflux port of the sulfur replenishment tank. This is used to observe the color of the material after secondary sulfur blending and to control the reflux ratio of the sulfur replenishment tank based on the color.

9. The apparatus for secondary sulfur preparation in the thionyl chloride distillation system according to claim 8, characterized in that, A sealed sampling port is installed on the pipeline at the outlet of the sulfur replenishment tank for collecting samples of thionyl chloride from the secondary sulfur preparation.

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