Secondary sulfur preparation method for thionyl chloride rectification system
By replacing solid sulfur with liquid sulfur and using two sulfur mixing and distillation treatments, the problems of high labor intensity and blockage in traditional methods are solved, the conversion rate of sulfur dichloride and the purity of sulfoxide chloride are improved, and the production cost is reduced.
Patent Information
- Application Number
- CN202510910735.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-02
- Publication Date
- 2025-08-19
AI Technical Summary
The traditional secondary sulfur distribution method has high workload and high labor intensity, the distillation tower is prone to blockage, and the sulfur dichloride does not fully react to affect product quality.
Liquid sulfur is used to replace solid sulfur, and through two sulfur combinations and two distillation treatments, the good fluidity and reaction activity of liquid sulfur are used to achieve deep conversion and efficient separation of sulfur dichloride.
It completely solved the problem that solid sulfur can easily block the pipeline, improved the conversion rate of sulfur dichloride and the purity of sulfoxide chloride products, and reduced production costs.
Smart Images
Figure CN120502117A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of fine chemical production, and particularly relates to a method for secondary sulfur distribution in a thionyl chloride distillation system. Background Art
[0002] Thionyl chloride (SOCl2) appears as a colorless or pale yellow, transparent liquid with a strong pungent odor. It is soluble in benzene, chloroform, and carbon tetrachloride. It decomposes in water to produce sulfurous acid and hydrogen chloride gas. When heated to 140°C, it decomposes into chlorine gas, sulfur dioxide, and sulfur monochloride. The chlorine atoms in thionyl chloride have a strong ability to replace hydroxyl and sulfhydryl groups, and can sometimes replace sulfur dioxide, oxygen, or hydrogen. It reacts with organic compounds containing hydroxyl groups, such as phenols or alcohols, to produce the corresponding chlorides, with sulfonic acids to produce sulfonyl chlorides, and with Grignard reagents to produce the corresponding sulfoxide compounds. It is primarily used in the production of dyes, pharmaceutical intermediates, food additives, and new lithium salts (LiFSI).
[0003] The main technologies currently used to produce thionyl chloride in my country include the chlorosulfonic acid method, the co-production method, the sulfur dioxide vapor method, and the sulfur trioxide vapor method. Most thionyl chloride manufacturers in my country use the sulfur dioxide vapor method due to its advanced technology, high product stability, colorless and transparent product, and virtually no "three wastes" generated during the production process.
[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 catalyst, crude thionyl chloride is generated. The reacted material is then distilled to obtain the final product.
[0005] The sulfur dioxide gas phase production process involves multiple reactions, mainly as follows: Overall reaction: S + 2Cl2 + SO2 = 2SOCl2 Sulfur dichloride reactor: Cl2+S2Cl2=2SCl2, Cl2+2S=S2Cl2 The main reaction of thionyl chloride synthesis reactor: 2Cl2+SO2+SCl2=2SOCl2 Side reaction: Cl2+SO2 =SO2Cl2 The main reaction of sulfur coordination: S+SCl2=S2Cl2 In the production of thionyl chloride, the mixed gas coming out of the thionyl chloride synthesis reactor in the synthesis process 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 point of sulfur dichloride is similar to that of thionyl chloride, 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 through sulfur matching in the distillation process. The boiling point of sulfur monochloride and thionyl chloride is quite different, and they are easy to separate by distillation.
[0006] The commonly used sulfur preparation method is to pass the crude thionyl chloride into the sulfur preparation kettle and then add sulfur to the sulfur preparation kettle. In actual production, secondary sulfur preparation is usually required, and traditional secondary sulfur preparation has three major technical defects: (1) Sulfur is added intermittently in the sulfur section at the top of the distillation tower, which is labor-intensive and labor-intensive. The sulfur replenishment process disrupts the balance in the distillation tower; (2) The reaction and blockage conditions in the sulfur section of the distillation tower need to be regularly monitored, and the accumulated materials need to be manually cleaned to prevent sulfur accumulation. (3) A small amount of unreacted sulfur dichloride exists in the product after secondary sulfur preparation, which affects product quality. Summary of the Invention
[0007] The invention provides a secondary sulfur preparation method for a thionyl chloride distillation system, which is used to solve the problem that a small amount of unreacted sulfur dichloride exists in the product of the thionyl chloride sulfur preparation system in the prior art.
[0008] The present invention provides a method for secondary sulfur addition in a thionyl chloride distillation system, comprising the following steps: The crude thionyl chloride outputted from the synthesis step is subjected to a primary sulfur addition treatment to obtain a primary sulfur addition thionyl chloride material; The sulfur-containing thionyl chloride material is subjected to a first distillation treatment to obtain a rectified thionyl chloride material and a crude sulfur monochloride material; The thionyl chloride material after distillation is mixed with liquid sulfur to perform a secondary sulfurization treatment to obtain a secondary sulfurized thionyl chloride material; The secondary sulfur-matched thionyl chloride material is subjected to a second distillation treatment to obtain a crude sulfur monochloride material and a thionyl chloride product.
[0009] Compared with the prior art, the present invention is advantageous in that: by providing a process flow of two sulfur preparation treatments and two distillation treatments, deep conversion and efficient separation of sulfur dichloride in crude thionyl chloride are achieved, liquid sulfur is used to replace traditional solid sulfur, and the good fluidity and reactivity of liquid sulfur are utilized to completely solve the technical problem that solid sulfur is prone to clogging pipelines and distillation towers, thereby improving the conversion rate of sulfur dichloride, deeply converting the sulfur dichloride that is not completely reacted in the pre-sulfur preparation process, and significantly improving the purity of the subsequent distillation thionyl chloride product.
[0010] Furthermore, the method further comprises: allowing at least a portion of the secondary sulfur-compounded thionyl chloride material to participate in the secondary sulfur-compounding treatment again.
[0011] Furthermore, the secondary sulfur-compounded thionyl chloride material that re-participates in the secondary sulfur-compounding treatment is 20-25%.
[0012] Furthermore, the temperature of the liquid sulfur is 135-145° C., and the flow rate is 20-30 kg / h.
[0013] Furthermore, liquid sulfur is transported using a segmented jacketed pipe, into which steam is introduced for heating, with a steam temperature of 150-160°C; thermal insulation material is provided on the outside of the jacketed pipe, and the segmented jacketed pipe includes 15-20 independent heating units, each of which is 4-6 meters long, and each section is connected by flanges.
[0014] Furthermore, the temperature of the first sulfurization treatment is 80-90° C., the pressure is 100-120 kPa, and solid sulfur is used in the first sulfurization treatment; and / or, the temperature of the second sulfurization treatment is 90-100° C., and the pressure is 250-300 kPa.
[0015] Furthermore, the temperature of the first distillation treatment is 90-130° C. and the pressure is 50-100 kPa; and / or the temperature of the thionyl chloride material after distillation is 60-80° C.
[0016] Furthermore, the liquid level in the secondary sulfur addition treatment is 60-70%; and / or the liquid level in the first distillation treatment is 50-80%.
[0017] Furthermore, the crude thionyl chloride comprises 65-75% thionyl chloride, 13-17% sulfur dichloride, 3-7% sulfur monochloride, 3-7% sulfur dioxide, and the remainder is chlorine.
[0018] Furthermore, after distillation, the thionyl chloride material includes 85-90% thionyl chloride, 5-7% sulfur dichloride, and the rest is chlorine and sulfur dioxide. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 The figure is a schematic diagram of a device for secondary sulfur distribution in a thionyl chloride distillation system according to one embodiment of the present invention.
[0020] Description of reference numerals: 1. Sulfur distribution tank; 2. Distillation tower; 3. Thionyl chloride delivery unit; 4. Sulfur replenishment tank; 5. Liquid sulfur supply unit; 31. First pump; 32. First flowmeter; 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 flowmeter; 55. Second shut-off valve; 6. Sealed sampling port. DETAILED DESCRIPTION
[0021] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.
[0022] The present invention provides a method for secondary sulfur addition in a thionyl chloride distillation system, comprising the following steps: The crude thionyl chloride outputted from the synthesis step is subjected to a primary sulfur addition treatment to obtain a primary sulfur addition thionyl chloride material; The sulfur-containing thionyl chloride material is subjected to a first distillation treatment to obtain a rectified thionyl chloride material and a crude sulfur monochloride material; The thionyl chloride material after distillation is mixed with liquid sulfur to perform a secondary sulfurization treatment to obtain a secondary sulfurized thionyl chloride material; The secondary sulfur-matched thionyl chloride material is subjected to a second distillation treatment to obtain a crude sulfur monochloride material and a thionyl chloride product.
[0023] The method for secondary sulfur preparation in a thionyl chloride distillation system provided by the present invention realizes deep conversion and efficient separation of sulfur dichloride in crude thionyl chloride by arranging a process flow of two sulfur preparation treatments and two distillation treatments, replaces traditional solid sulfur with liquid sulfur, and thoroughly solves the technical problem that solid sulfur is prone to clogging pipelines and distillation towers by utilizing the good fluidity and reactivity of liquid sulfur. The conversion rate of sulfur dichloride is improved, the sulfur dichloride that is not completely reacted in the pre-sulfur preparation process is deeply converted, and the purity of the subsequent distillation thionyl chloride product is significantly improved.
[0024] Furthermore, the method further includes re-entering the secondary sulfur-compounding thionyl chloride material for the secondary sulfur-compounding process. By recirculating the secondary sulfur-compounding thionyl chloride material for the secondary sulfur-compounding process, a circulating reaction system is formed, which not only improves sulfur utilization but also ensures thorough mixing of the reaction materials and extends the reaction time. This design optimizes reaction conditions, resulting in more complete sulfur dichloride conversion, while also reducing fresh sulfur consumption and lowering production costs.
[0025] Optionally, the secondary sulfur-compounded thionyl chloride material that re-participates in the secondary sulfur-compounding treatment is 20-25%.
[0026] Furthermore, the temperature of the liquid sulfur is 135-145°C and the flow rate is 20-30 kg / h, which further improves the fluidity of the sulfur and ensures its full reaction with the thionyl chloride material.
[0027] In a specific embodiment, liquid sulfur is transported using a segmented jacketed pipe. Steam is introduced into the segmented jacketed pipe for heating, and the steam temperature is 150-160°C. The jacketed pipe is provided with thermal insulation material on the outside. The segmented jacketed pipe includes 15-20 independent heating units, each of which is 4-6 meters long and is connected by flanges.
[0028] Specifically, the temperature of the primary sulfurization treatment is 80-90°C, the pressure is 100-120 kPa, and solid sulfur is used for the primary sulfurization. When solid sulfur is used for the primary sulfurization, the reaction system contains intermediate products such as S2Cl2 that are not completely decomposed. The slow dissolution characteristics of solid sulfur can form a gradient reaction with these components, avoiding instantaneous overheating of the reaction; further, it prevents excessive conversion of sulfur dichloride caused by the violent reaction in the primary sulfurization stage to produce side reactions.
[0029] The temperature of the first distillation treatment is 90~130℃ and the pressure is 50~100kPa; the temperature of the thionyl chloride material after distillation is 60~80℃; the liquid level in the secondary sulfurization treatment is 60~70%; and the liquid level in the first distillation treatment is 50~80%.
[0030] The crude thionyl chloride output from the synthesis process consists of 65-75% thionyl chloride, 13-17% sulfur dichloride, 3-7% sulfur monochloride, 3-7% sulfur dioxide, and the remainder is a small amount of chlorine. The primary sulfur-blending thionyl chloride feed consists of 62-72% thionyl chloride, 2-6% sulfur dichloride, 18-22% sulfur monochloride, 3-6% sulfur dioxide, and the remainder is a small amount of sulfur and chlorine. The thionyl chloride feed after rectification consists of 85-90% thionyl chloride, 5-7% sulfur dichloride, and the remainder is a small amount of chlorine and sulfur dioxide. The crude sulfur monochloride feed consists of 93-98% sulfur monochloride, 1-3% sulfur, and the remainder is a small amount of thionyl chloride. The secondary sulfur-blending thionyl chloride feed consists of 80-90% thionyl chloride, 4-8% sulfur monochloride, and the remainder is a small amount of chlorine and sulfur dioxide. The crude sulfur monochloride feed can be output as sulfur monochloride product and sent to the synthesis process.
[0031] See also Figure 1 The present invention provides a device for performing the above-mentioned method of secondary sulfur addition in the thionyl chloride distillation system, comprising: a sulfur addition tank 1, a distillation tower 2, two sulfur supply tanks 4 arranged in parallel, and a liquid sulfur supply unit 5; The crude thionyl chloride output from the synthesis step is connected to the inlet of the sulfur preparation tank 1, the outlet of the sulfur preparation tank 1 is connected to the inlet of the distillation tower 2, the top outlet of the distillation tower 2 is connected to the material inlets of the two sulfur supplement tanks 4 through the thionyl chloride delivery unit 3, the outlet of the liquid sulfur supply unit 5 is connected to the liquid sulfur inlets of the two sulfur supplement tanks 4, and the discharge port of the sulfur supplement tank 4 is used to output the secondary sulfur preparation thionyl chloride.
[0032] The device for secondary sulfur preparation in a thionyl chloride distillation system provided by the present invention adopts a liquid sulfur supply unit 5, so that liquid sulfur replaces traditional solid sulfur. By utilizing the good fluidity and reactivity of liquid sulfur, the technical problem of solid sulfur easily clogging pipelines and a distillation tower 2 is completely solved, thereby improving the conversion rate of sulfur dichloride. A parallel sulfur replenishing tank 4 system is provided, and continuous discharge of the sulfur replenishing tank 4 is achieved through intermittent operation, so that the sulfur dichloride that is not completely reacted in the pre-sulfur preparation process is deeply converted, thereby significantly improving the purity of the subsequent distillation thionyl chloride product.
[0033] Furthermore, the crude thionyl chloride conveying unit 3 includes a first pump 31, a first flowmeter 32, a liquid level regulating valve 33 and a shut-off valve group connected in sequence. The shut-off valve group includes two parallel first shut-off valves 34, which correspond to the material inlets of the two sulfur replenishing tanks 4 respectively.
[0034] By providing a first pump 31 to ensure stable delivery of crude thionyl chloride, a first flowmeter 32 to achieve precise metering, a liquid level regulating valve 33 to automatically control the liquid level in the sulfur replenishing tank 4, and two parallel first shut-off valves 34 to achieve flexible switching between the two sulfur replenishing tanks 4, the continuity of production is ensured, 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 , a steam coil is provided outside the liquid sulfur storage tank 51 , and thermal insulation material is also provided outside the steam coil. The steam coil and the thermal insulation material are used to heat and keep the liquid sulfur in the liquid sulfur storage tank 51 warm.
[0036] The dual design of steam coils and thermal insulation materials allows precise control of the sulfur temperature within the liquid sulfur storage tank 51, further ensuring sulfur fluidity, preventing the impact of temperature fluctuations on reaction efficiency, and significantly reducing heat loss. Optionally, the liquid sulfur temperature is 135-145°C, 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 flowmeter 54 and a second shut-off valve 55. The third pump 53, the second flowmeter 54 and the second shut-off valve 55 are arranged on the segmented jacketed pipe 52. The liquid outlet of the liquid sulfur storage tank 51 is connected to the liquid sulfur inlets of the two sulfur replenishing tanks 4 respectively through the segmented jacketed pipe 52.
[0038] Liquid sulfur is transported using a segmented jacketed pipe 52, which, in conjunction with a third pump 53, a second flow meter 54 and a second shut-off valve 55, achieves precise metering and temperature-controlled transportation of liquid sulfur, further ensuring that the sulfur maintains an optimal reaction temperature during transportation and facilitating system maintenance and overhaul.
[0039] Specifically, the segmented jacketed pipe 52 includes 15-20 independent heating units, each of which is 4-6 meters long and is connected by flanges, further ensuring that the sulfur maintains the optimal reaction temperature during transportation.
[0040] In a specific embodiment, a second pump 41 is further included, the discharge port of the sulfur replenishing tank 4 is connected to the inlet of the second pump 41, the outlet of the second pump 41 is connected to the reflux port of the sulfur replenishing tank 4, and the outlet of the second pump 41 is also used to output the secondary sulfur-matched thionyl chloride.
[0041] The second pump 41 circulates the material, further improving the product reaction efficiency and preventing liquid sulfur deposition. After the reaction is completed, the second pump 41 is used to feed the material into a subsequent distillation tower for further purification of thionyl chloride.
[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 distilled material and control the opening and closing of the second shut-off valve 55 in the liquid sulfur supply unit 5 based on this color. As can be understood, the thionyl chloride material after primary sulfur blending and distillation contains a large amount of sulfur dichloride, resulting in a reddish-brown color. By providing first sight glass 42, the amount of liquid sulfur to be added can be determined based on 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 is used to observe the color of the material after the secondary sulfurization and to control the reflux ratio of the sulfur replenishment tank 4 based on the color. Similarly, after the secondary sulfurization, the sulfur dichloride in the material is converted into sulfur monochloride, and the material changes from red to light yellow. The operator can adjust the reflux ratio based on the color change of the reaction product, optimize the reaction conditions, ensure the full conversion of the sulfur dichloride, and improve the quality and stability of the final product.
[0044] A sealed sampling port 6 is provided on the pipe at the discharge port of the sulfur replenishing tank 4 for collecting the secondary sulfur-matched thionyl chloride sample.
[0045] Furthermore, it also includes a DCS control system, which includes: a PID adjustment module interlocked with the first flowmeter 32 and the second flowmeter 54; a liquid level control module communicatively connected to the liquid level regulating valve 33; and a sulfur tank 4 switching module based on time control.
[0046] The system's integrated PID regulation module can dynamically adjust the ratio of material and liquid sulfur based on the real-time data of the first flowmeter 32 and the second flowmeter 54, ensuring that the reaction process is always in the optimal state; the liquid level control module realizes automatic and stable control of the liquid level in the sulfur supply tank 4 through linkage with the liquid level regulating valve 33, avoiding the uncertainty of manual adjustment; and the sulfur supply tank 4 switching module based on time control realizes the intelligent rotation operation of the two parallel sulfur supply tanks 4, which not only ensures production continuity but also extends the service life of the equipment.
[0047] Specifically, the temperature of the rectified thionyl chloride material discharged from the top outlet of distillation tower 2 is 60-80°C, the liquid level in sulfur replenishment tank 4 is controlled at 60-70%, and the liquid level in distillation tower 2 is controlled by liquid level regulating valve 33 to 50-80%. A first shut-off valve 34 controls the crude thionyl chloride product to enter the two sulfur replenishment tanks 4 for intermittent operation, improving product reaction efficiency.
[0048] In one specific embodiment, after crude thionyl chloride enters the distillation tower 2, it passes through a first pump 31, a first flowmeter 32, a liquid level regulating valve 33, and a first shut-off valve 34 from the bottom of the tower into the sulfur feed tank 4. The liquid level of the distillation tower 2 and the liquid level regulating valve 33 are arranged in cascade to automatically control the liquid level and flow of the distillation tower 2. The sulfur feed tank 4 is operated intermittently, and a second pump 41 is provided at the bottom of the sulfur feed tank 4 for circulating materials and transporting materials to subsequent processes. The liquid sulfur storage tank 51 enters the sulfur feed tank 4 through a jacketed pipe, sequentially passes through a third pump 53, a second flowmeter 54, and a second shut-off valve 55.
[0049] Hereinafter, a device for secondary sulfur distribution in a thionyl chloride distillation system provided by the present invention will be described in detail through specific embodiments. Example 1
[0050] (1) The crude thionyl chloride (72.4% thionyl chloride, 16.3% sulfur dichloride, 8.7% sulfur monochloride, 4.6% sulfur dioxide, and the rest is a small amount of chlorine) output from the synthesis step is fed into the sulfur preparation tank 1 for a primary sulfur preparation treatment to obtain a primary sulfur preparation thionyl chloride material (69.7% thionyl chloride, 2.3% sulfur dichloride, 21.9% sulfur monochloride, 5.5% sulfur dioxide, and the rest is a small amount of sulfur and chlorine); wherein the primary sulfur preparation temperature is 80-90°C and the pressure is 100-120 kPa, and the sulfur preparation tank 1 contains solid sulfur; (2) sending the sulfur-added thionyl chloride material to the distillation tower 2 for the first distillation treatment to obtain the rectified thionyl chloride material (temperature 60°C, containing 90.3% thionyl chloride, 4.2% sulfur dichloride, and the rest being a small amount of chlorine and sulfur dioxide) and the crude sulfur monochloride material; (3) The liquid sulfur in the liquid sulfur storage tank 51 is fed into the sulfur replenishing tank 4 by the third pump 53 through the jacketed pipe, the second flow meter 54 and the shut-off valve. The flow rate is controlled at 20 kg / h. The temperature of the steam introduced into the jacketed pipe is 150-160°C. The jacketed pipe should be drained of steam condensate to prevent uneven steam distribution, which may cause sulfur crystallization and solidification to block the pipe.
[0051] (4) The thionyl chloride material after distillation flowing out from the top of the distillation tower 2 is pumped by the first pump 31 through the first flow meter 32, the liquid level regulating valve 33 and the first sight glass 42 into the sulfur replenishing tank 4, and the flow rate is controlled at 3000 kg / h; (5) The second pump 41 at the bottom of the sulfur replenishing tank 4 is started, and the reaction begins to circulate. After the reaction is completed, the material is sent to the subsequent process. The material composition is analyzed through a closed sampler in the delivery pipeline. The measured content of thionyl chloride is 85% and the content of sulfur monochloride is 6%. The material is then sent to the subsequent distillation system for distillation separation. Example 2
[0052] (1) The crude thionyl chloride (74.3% thionyl chloride, 15.7% sulfur dichloride, 7.4% sulfur monochloride, 6.2% sulfur dioxide, and the rest is a small amount of chlorine) output from the synthesis step is fed into the sulfur preparation tank 1 for a primary sulfur preparation treatment to obtain a primary sulfur preparation thionyl chloride material (71.3% thionyl chloride, 3.3% sulfur dichloride, 22.3% sulfur monochloride, 4.7% sulfur dioxide, and the rest is a small amount of sulfur and chlorine); wherein the primary sulfur preparation temperature is 80-90°C and the pressure is 100-120 kPa, and the sulfur preparation tank 1 contains solid sulfur; (2) sending the sulfur-added thionyl chloride material to the distillation tower 2 for the first distillation treatment to obtain the rectified thionyl chloride material (temperature 70°C, containing 92.3% thionyl chloride, 2.7% sulfur dichloride, and the rest being a small amount of chlorine and sulfur dioxide) and the crude sulfur monochloride material; (3) The liquid sulfur in the liquid sulfur storage tank 51 is fed into the sulfur replenishing tank 4 by the third pump 53 through the jacketed pipe, the second flow meter 54 and the shut-off valve. The flow rate is controlled at 25 kg / h. The temperature of the steam introduced into the jacketed pipe is 150-160°C. The jacketed pipe should be drained of steam condensate to prevent uneven steam distribution, which may cause sulfur crystallization and solidification to block the pipe.
[0053] (4) The thionyl chloride material after distillation flowing out from the top of the distillation tower 2 is pumped by the first pump 31 through the first flow meter 32, the liquid level regulating valve 33 and the first sight glass 42 into the sulfur replenishing tank 4, and the flow rate is controlled at 3000 kg / h; (5) The second pump 41 at the bottom of the sulfur replenishing tank 4 is started, and the reaction begins to circulate. After the reaction is completed, the material is sent to the subsequent process. The material composition is analyzed through a closed sampler in the delivery pipeline. The measured content of thionyl chloride is 87% and the content of sulfur monochloride is 4%. The material is then sent to the subsequent distillation system for distillation separation. Example 3
[0054] (1) The crude thionyl chloride (71.3% thionyl chloride, 16.5% sulfur dichloride, 7.6% sulfur monochloride, 6.7% sulfur dioxide, and the rest is a small amount of chlorine) output from the synthesis step is fed into the sulfur preparation tank 1 for a primary sulfur preparation treatment to obtain a primary sulfur preparation thionyl chloride material (68.7% thionyl chloride, 6.7% sulfur dichloride, 19.7% sulfur monochloride, 5.3% sulfur dioxide, and the rest is a small amount of sulfur and chlorine); wherein the primary sulfur preparation temperature is 80-90°C and the pressure is 100-120 kPa, and the sulfur preparation tank 1 contains solid sulfur; (2) sending the sulfur-containing thionyl chloride material to the distillation tower 2 for the first distillation treatment to obtain the rectified thionyl chloride material (temperature 70°C, containing 87% thionyl chloride, 4.2% sulfur dichloride, and the rest being a small amount of chlorine and sulfur dioxide) and the crude sulfur monochloride material; (3) The liquid sulfur in the liquid sulfur storage tank 51 is fed into the sulfur replenishing tank 4 by the third pump 53 through the jacketed pipe, the second flow meter 54 and the shut-off valve. The flow rate is controlled at 30 kg / h. The temperature of the steam introduced into the jacketed pipe is 150-160°C. The jacketed pipe should be drained of steam condensate to prevent uneven steam distribution, which may cause sulfur crystallization and solidification to block the pipe.
[0055] (4) The thionyl chloride material after distillation flowing out from the top of the distillation tower 2 is pumped by the first pump 31 through the first flow meter 32, the liquid level regulating valve 33 and the first sight glass 42 into the sulfur replenishing tank 4, and the flow rate is controlled at 3000 kg / h; (5) The second pump 41 at the bottom of the sulfur replenishing tank 4 is started, and the reaction begins to circulate. After the reaction is completed, the material is sent to the subsequent process. The material composition is analyzed through a closed sampler in the delivery pipeline. The measured content of thionyl chloride is 90% and the content of sulfur monochloride is 2%. The material is then sent to the subsequent distillation system for distillation separation.
[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. If these modifications and variations fall within the scope of the claims of the present invention and their equivalent technologies, they should be considered to be within the scope of protection of the present invention.
Claims
1. A method for secondary sulfur addition in a thionyl chloride distillation system, characterized in that: The following steps are involved: The crude thionyl chloride outputted from the synthesis step is subjected to a primary sulfur addition treatment to obtain a primary sulfur addition thionyl chloride material; The sulfur-containing thionyl chloride material is subjected to a first distillation treatment to obtain a rectified thionyl chloride material and a crude sulfur monochloride material; The thionyl chloride material after distillation is mixed with liquid sulfur to perform a secondary sulfurization treatment to obtain a secondary sulfurized thionyl chloride material; The secondary sulfur-matched thionyl chloride material is subjected to a second distillation treatment to obtain a crude sulfur monochloride material and a thionyl chloride product.
2. The method for secondary sulfur distribution in a thionyl chloride distillation system according to claim 1, characterized in that: Also includes: At least part of the secondary sulfur-matching thionyl chloride material is made to participate in the secondary sulfur-matching treatment again.
3. The method for secondary sulfur addition in a thionyl chloride distillation system according to claim 2, characterized in that: The amount of secondary sulfur-compounded thionyl chloride material that re-participates in the secondary sulfur-compounding treatment is 20~25%.
4. The method for secondary sulfur addition in a thionyl chloride distillation system according to any one of claims 1 to 3, characterized in that: The temperature of liquid sulfur is 135-145°C, and the flow rate is 20-30 kg / h.
5. The method for secondary sulfur addition in a thionyl chloride distillation system according to claim 4, characterized in that: Liquid sulfur is transported using segmented jacketed pipes, with steam introduced into the pipes for heating at a temperature of 150-160°C. Thermal insulation material is provided on the outside of the pipes, and the pipes include 15-20 independent heating units, each 4-6 meters long, connected by flanges.
6. The method for secondary sulfur addition in a thionyl chloride distillation system according to any one of claims 1 to 3, characterized in that: The temperature of the primary sulfur treatment is 80-90°C, the pressure is 100-120 kPa, and solid sulfur is used for the primary sulfur treatment; and / or, The temperature of the secondary sulfur treatment is 90~100℃ and the pressure is 250~300kPa.
7. The method for secondary sulfur addition in a thionyl chloride distillation system according to any one of claims 1 to 3, characterized in that: The temperature of the first distillation treatment is 90-130° C. and the pressure is 50-100 kPa; and / or, The temperature of the thionyl chloride material after distillation is 60~80℃.
8. The method for secondary sulfur addition in a thionyl chloride distillation system according to any one of claims 1 to 3, characterized in that: The liquid level in the secondary sulfur treatment is 60-70%; and / or, The liquid level in the first distillation treatment is 50 to 80%.
9. The method for secondary sulfur addition in a thionyl chloride distillation system according to any one of claims 1 to 3, characterized in that: The crude thionyl chloride comprises 65-75% thionyl chloride, 13-17% sulfur dichloride, 3-7% sulfur monochloride, 3-7% sulfur dioxide, and the remainder is chlorine.
10. The method for secondary sulfur addition in a thionyl chloride distillation system according to any one of claims 1 to 3, characterized in that: After distillation, the thionyl chloride material includes thionyl chloride 85-90%, sulfur dichloride 5-7%, and the rest is chlorine and sulfur dioxide.