Dimethyl sulfoxide synthesis system and synthesis method

Abstract

A dimethyl sulfoxide synthesis system and a synthesis method, the system comprising: a fixed bed reactor (2) used to synthesize dimethyl sulfide, and an oxidation reactor (4) used to synthesize dimethyl sulfoxide. An external intensification unit (9) is disposed outside the oxidation reactor (4), the external intensification unit (9) comprising a first intensification reactor (901) and a second intensification reactor (902), the first intensification reactor (901) being disposed above the second intensification reactor (902), the first intensification reactor (901) being connected to a discharge port at a bottom end of the fixed bed reactor (2), the second intensification reactor (902) being connected to a nitrogen dioxide or oxygen storage tank (13), a connecting pipe (903) being disposed between the first intensification reactor (901) and the second intensification reactor (902), and a static mixer (904) being disposed in the connecting pipe (903).

Description

A synthesis system and method for dimethyl sulfoxide Technical Field The present invention belongs to the technical field of dimethyl sulfoxide production, and more specifically, it belongs to a synthesis system and method for dimethyl sulfoxide. Background Art Dimethyl sulfoxide is an extremely important organic solvent in the fields of medicine, chemical engineering, and materials science. Industrially, several methods are mainly used for the synthesis of dimethyl sulfoxide: nitric acid method, hydrogen peroxide method, ozone method, and nitrogen dioxide method. Among them, the nitrogen dioxide method has become the mainstream industrial production method due to its high production efficiency and low safety risk. In this method, liquid-phase oxidation and gas-phase oxidation are two commonly used processes. Liquid-phase oxidation usually uses methanol and hydrogen sulfide as raw materials, and dimethyl sulfide is generated under the action of γ-aluminum oxide, and then nitrogen dioxide or oxygen is used for the oxidation reaction to produce crude dimethyl sulfoxide, and finally refined dimethyl sulfoxide is obtained by vacuum distillation. Although the liquid-phase oxidation method has advantages in industrial production, there are still some problems and disadvantages. The reaction conditions of the liquid-phase oxidation method are difficult to control, and in the traditional process of synthesizing dimethyl sulfoxide, the conversion rate of raw materials is low and the product purity is low. In view of this, the present invention is specifically proposed. Summary of the Invention The first object of the present invention is to provide a synthesis system for dimethyl sulfoxide. Aiming at the problems of low raw material conversion rate and difficult reaction condition control in the prior art, a reasonable process flow is designed. Based on the intensified reaction technology, the raw materials are broken and dispersed into micron-sized bubbles through an intensified reactor, greatly improving the mass transfer rate of gaseous raw materials to the reaction liquid and the macroscopic reaction rate, and increasing the raw material conversion rate. The second object of the present invention is to provide a method for synthesizing dimethyl sulfoxide using the above dimethyl sulfoxide synthesis system. This method is simple to operate, the operating conditions are milder, the energy consumption is low, and it achieves a better treatment effect than the prior art process. To achieve the above objects of the present invention, the following technical solutions are specifically adopted: The present invention provides a synthesis system for dimethyl sulfoxide, including: A fixed-bed reactor for synthesizing dimethyl sulfide and an oxidation reactor for synthesizing dimethyl sulfoxide; An external intensification unit is arranged outside the oxidation reactor. The external intensification unit includes a first intensification reactor and a second intensification reactor. The first intensification reactor is arranged above the second intensification reactor. The first intensification reactor is connected to the discharge port at the bottom end of the fixed-bed reactor. The second intensification reactor is connected to a nitrogen dioxide or oxygen storage tank. A communication pipeline is arranged between the first intensification reactor and the second intensification reactor, and a static mixer is arranged in the communication pipeline. In the prior art, the following problems mainly exist in the synthesis of dimethyl sulfoxide: the incompleteness of the reaction in the synthesis of dimethyl sulfoxide by traditional processes results in low raw material conversion rate, which means that in the oxidation stage of dimethyl sulfide, the raw materials are not completely converted into the target product, thereby reducing the overall production efficiency and economy; at the same time, in the prior art, during the synthesis of dimethyl sulfoxide, the reaction energy consumption is high, the reaction temperature and pressure of the oxidation reactor are high, and the production capacity is relatively low. To solve the above technical problems, the present invention provides a synthesis system for dimethyl sulfoxide. The overall structure of this synthesis system is simple. By providing an external strengthening unit outside the oxidation reactor, the raw materials entering the oxidation reactor can be initially broken and dispersed, and the dimethyl sulfide liquid and nitrogen dioxide gas or oxygen are broken and dispersed into micron-sized microbubbles, increasing the interfacial mass transfer area between the gas-liquid two phases, and thus improving the raw material conversion rate. In the external strengthening unit of the present invention, the first strengthening reactor is arranged above the second strengthening reactor. This is because the dimethyl sulfide liquid is introduced into the first strengthening reactor, and nitrogen dioxide or oxygen is introduced into the second strengthening reactor. The liquid flows from top to bottom, and the gas moves upward from bottom to top, thereby increasing the contact time between the two; at the same time, the present invention is provided with a connecting pipe between the first strengthening reactor and the second strengthening reactor, which can provide a mixing place for the gas-liquid two phases. At the same time, the static mixer arranged inside the connecting pipe can cooperate with the strengthening reactor to mix the microbubbles coming out of the strengthening reactor more evenly, so that the tiny bubbles generated by the strengthening reactor can contact the surrounding fluid more effectively, thereby improving the reaction efficiency. Preferably, an internal strengthening unit is arranged inside the oxidation reactor. The internal strengthening unit includes a third strengthening reactor arranged at the top of the oxidation reactor and a fourth strengthening reactor arranged below the third strengthening reactor. The third strengthening reactor is connected to the connecting pipe, and the fourth strengthening reactor is connected to the nitrogen dioxide or oxygen storage tank. By providing the internal strengthening unit, it forms a strengthening system with the external strengthening unit arranged outside the oxidation reactor. The internal strengthening reactor can perform secondary fragmentation and dispersion on the mixed materials entering the oxidation reactor, breaking the reaction raw materials into extremely small micron-sized bubbles, further increasing the interfacial mass transfer area. At the same time, the fourth strengthening reactor of the present invention is directly connected to the nitrogen dioxide or oxygen storage tank. The purpose of this setting is to ensure that the carbon dioxide or oxygen in the oxidation reactor is in excess, so that the dimethyl sulfide can react fully. Preferably, the internal strengthening unit is arranged inside the oxidation reactor. The internal strengthening unit includes a third strengthening reactor arranged at the top of the oxidation reactor and a fourth strengthening reactor arranged below the third strengthening reactor. The third strengthening reactor is connected to the connecting pipe, and the fourth strengthening reactor is connected to the nitrogen dioxide or oxygen storage tank. By providing the internal strengthening unit, it forms a strengthening system with the external strengthening unit arranged outside the oxidation reactor. The internal strengthening reactor can perform secondary fragmentation and dispersion on the mixed materials entering the oxidation reactor, breaking the reaction raw materials into extremely small micron-sized bubbles, further increasing the interfacial mass transfer area. At the same time, the fourth strengthening reactor of the present invention is directly connected to the nitrogen dioxide or oxygen storage tank. The purpose of this setting is to ensure that the carbon dioxide or oxygen in the oxidation reactor is in excess, so that the dimethyl sulfide can react fully. Preferably, the outlet of the third intensifying reactor is opposite to the outlet of the fourth intensifying reactor. A nozzle is connected to the outlet of the third intensifying reactor, and a stirrer is arranged at the outlet of the fourth intensifying reactor. By making the outlets of the third intensifying reactor and the fourth intensifying reactor with built-in intensifying units opposite to each other, counterflow can be achieved. By arranging a nozzle at the outlet of the third intensifying reactor and using it in cooperation with the third intensifying reactor, the flow rate of the microbubbles coming out of the third intensifying reactor can be accurately controlled, and at the same time, the microbubbles are evenly sprayed inside the oxidation reaction kettle to achieve the effect of efficient mixing. A stirrer is arranged at the outlet of the fourth intensifying reactor of the present invention. The purpose of this arrangement is that the gas coming out of the fourth intensifying reactor is nitrogen dioxide gas or oxygen, which needs to fully react with the dimethyl sulfide liquid coming out of the third intensifying reactor. Since the third intensifying reactor is arranged above, arranging the stirrer can not only evenly diffuse the gas coming out of the fourth intensifying reactor, but also cooperate with the third intensifying reactor to stir and mix the dimethyl sulfide liquid coming out of the third intensifying reactor with the gas coming out of the fourth intensifying reactor, thereby improving the conversion rate between the raw materials. Preferably, a shunt assembly is arranged directly below the built-in intensifying unit. The shunt assembly includes a plurality of shunt plates arranged in sequence from top to bottom, and the distance between adjacent two shunt plates gradually becomes smaller. The shunt assembly of the present invention is arranged below the built-in intensifying unit. The advantage of this arrangement is that it can extend the reaction time between the microbubble mixed materials coming out of the built-in intensifying reactor. The gradually decreasing distance between adjacent two shunt plates can enhance the turbulence degree in the fluid, thereby improving the mixing effect; at the same time, it can effectively control the fluid velocity, reduce the energy loss caused by fluid friction or turbulence, and improve the energy efficiency of the overall system. Preferably, shunt holes are arranged on the shunt plates, and the aperture of the shunt holes is 50 - 100 μm. The aperture on the shunt plates of the present invention is set to be in the micron range, which can filter out large bubbles, thereby improving the overall reaction efficiency. Preferably, the static mixer is a spiral metal tube, and the spiral metal tube spirally extends along the longitudinal axis of the connecting pipe, and the spiral metal tube is adapted to the length of the connecting pipe. Preferably, through holes are arranged on the surface of the spiral metal tube. By selecting a spiral metal tube, the reaction time can be extended, and at the same time, the fluid can be guided to flow in a more effective way, reducing turbulence and fluid resistance, and improving the heat exchange efficiency; at the same time, arranging through holes can reduce the resistance of the fluid in the pipe. Preferably, a vacuum distillation column is connected to the crude product outlet at the bottom of the oxidation reactor, and the side wall of the vacuum distillation column is connected to the third intensification reactor to recover unreacted raw materials. By providing the vacuum distillation column, the unreacted raw materials are returned to the oxidation reactor for further reaction, thereby increasing the conversion rate of the raw materials. In the present invention, by providing the fixed bed reactor and the oxidation reactor, a stable reaction environment can be provided for synthesizing dimethyl sulfide and converting dimethyl sulfide into dimethyl sulfoxide; at the same time, an external intensification unit is provided outside the oxidation reactor, and through the combined action of the first intensification reactor and the second intensification reactor, the gas-liquid two-phase raw materials can be converted into micron-sized bubbles, increasing the phase boundary mass transfer area of the gas-liquid two-phase; through the internal intensification unit, used in combination with the external intensification unit, an intensification system is formed to further break and disperse the mixed material entering the oxidation reactor, thereby increasing the reaction efficiency and the selectivity of the raw materials. In the present invention, a connecting pipe is provided inside the external intensification unit, and a static mixer is provided inside the connecting pipe. By providing the connecting pipe, the uniform mixing of the materials can be promoted, and it can play a role in supporting the first intensification reactor and the second intensification reactor; at the same time, both ends of the static mixer are respectively connected to the first intensification reactor and the second intensification reactor, and the reaction raw materials coming out of the intensification reactor can be uniformly mixed, and the large bubbles can be filtered out through the through holes, increasing the reaction rate. In the present invention, by respectively connecting a nozzle and a stirrer to the ends of the two intensification reactors of the internal intensification unit, the microbubbles coming out of the intensification reactor can be stirred and mixed in a timely manner, further increasing the reaction rate and the conversion rate of the raw materials; at the same time, a shunt component is provided below the internal intensification reactor, and it is used in combination with the internal intensification unit to filter the mixed material coming out of the internal intensification unit, ensuring that only micron-sized microbubbles flow into the bottom of the oxidation reactor, and at the same time, the reaction time can be extended and the conversion rate of the raw materials can be increased. Those skilled in the art will appreciate that the enhanced reactor used in the present invention has been embodied in the inventor's prior patents, such as patents with application numbers CN201610641119.6, CN201610641251.7, CN201710766435.0, CN106187660, CN105903425A, CN109437390A, CN205833127U and CN207581700U. The prior patent CN201610641119.6 describes in detail the specific product structure and working principle of the micron bubble generator (i.e., enhanced reactor). The application document states that "the micron bubble generator includes a main body and a secondary crushing member, a cavity is provided in the main body, an inlet connected to the cavity is provided on the main body, the first and second opposite ends of the cavity are open, wherein the cross-sectional area of the cavity decreases from the middle of the cavity to the first and second ends of the cavity; the secondary crushing member is provided at at least one of the first and second ends of the cavity, a part of the secondary crushing member is provided in the cavity, and an annular channel is formed between the secondary crushing member and the through holes open at both ends of the cavity. The micron bubble generator also includes an air inlet pipe and a liquid inlet pipe." From the specific structure disclosed in the application document, it can be known that its specific working principle is: the liquid enters the micron bubble generator tangentially through the liquid inlet pipe, rotates at ultra-high speed and cuts the gas, so that the gas bubbles are broken into micron-level microbubbles, thereby increasing the mass transfer area between the liquid phase and the gas phase, and the micron bubble generator in the patent belongs to a pneumatic enhanced reactor. In addition, the prior patent 201610641251.7 records that the primary bubble breaker has a circulating liquid inlet, a circulating gas inlet and a gas-liquid mixture outlet, and the secondary bubble breaker connects the feed inlet with the gas-liquid mixture outlet, indicating that the bubble breaker requires gas-liquid mixture to enter. In addition, it can be seen from the following figures that The primary bubble breaker mainly uses circulating fluid as power, so in fact the primary bubble breaker belongs to a hydraulic enhanced reactor. The secondary bubble breaker simultaneously passes the gas-liquid mixture into an elliptical rotating ball for rotation, thereby achieving bubble breaking during the rotation process, so the secondary bubble breaker actually belongs to a gas-liquid linkage enhanced reactor. In fact, both the hydraulic enhanced reactor and the gas-liquid linkage enhanced reactor are a specific form of enhanced reactor. However, the enhanced reactor used in the present invention is not limited to the above-mentioned forms. The specific structure of the bubble breaker recorded in the prior patent is only one of the forms that can be adopted by the enhanced reactor of the present invention. In addition, it is recorded in the prior patent 201710766435.0 that "the principle of the bubble breaker is to achieve gas mutual collision through high-speed jet flow", and it is also elaborated that it can be used in a microinterface intensification reactor to verify the relevance between the bubble breaker itself and the microinterface generator; moreover, the prior patent CN106187660 also has relevant records on the specific structure of the bubble breaker. Specifically, see paragraphs

[0031] -

[0041] , as well as the attached drawings. It elaborates in detail the specific working principle of the bubble breaker S-2. The top of the bubble breaker is the liquid-phase inlet, and the side is the gas-phase inlet. The liquid phase entering from the top provides the entrainment power, thereby achieving the effect of crushing into ultrafine bubbles. It can also be seen from the attached drawings that the bubble breaker has a conical structure, and the diameter of the upper part is larger than that of the lower part, which is also to enable the liquid phase to better provide the entrainment power. Since in the initial stage of the prior patent application, the intensification reactor was just developed, it was early named as a microbubble generator (CN201610641119.6), a bubble breaker (201710766435.0), etc. With continuous technological improvement, it was later renamed as an intensification reactor. Now, the intensification reactor in the present invention is equivalent to the previous microbubble generator, bubble breaker, etc., only with different names. In summary, the intensification reactor of the present invention belongs to the prior art. Preferably, the dimethyl sulfoxide synthesis system of the present invention further includes a heating furnace, an azeotropic rectification tower, a neutralization evaporation reactor, an incinerator, and a waste water storage tank; The heating furnace is connected to the feed inlet of the fixed-bed reactor, and the heating furnace is used to preheat methanol and hydrogen sulfide; The azeotropic rectification tower is arranged between the fixed-bed reactor and the oxidation reactor, and the azeotropic rectification tower is used to refine the dimethyl sulfide coming out of the fixed-bed reactor; The neutralization evaporation reactor is arranged between the oxidation reactor and the azeotropic rectification tower and is used to filter and remove impurities from dimethyl sulfoxide; The incinerator is respectively connected to the fixed-bed reactor, the azeotropic rectification tower, the oxidation reactor, the neutralization evaporation reactor, and the vacuum rectification tower; The waste water storage tank is connected to the vacuum rectification tower to store waste water. By setting up the heating furnace, the azeotropic rectification tower, the neutralization evaporation reactor, the incinerator, and the waste water storage tank, the synthesis system of the present invention is made more perfect. At the same time, the comprehensive system design ensures the continuity and efficiency of the production process and reduces environmental pollution. In addition to this, the present invention also provides a method for synthesizing dimethyl sulfoxide, which uses the above synthesis system to synthesize dimethyl sulfoxide. Preferably, the method for synthesizing dimethyl sulfoxide comprises the following steps: dimethyl sulfide is synthesized from methanol and hydrogen sulfide, and dimethyl sulfide is subjected to an oxidation reaction with nitrogen dioxide or oxygen to produce dimethyl sulfoxide. Preferably, the reaction temperature during the oxidation reaction is 30-50 °C, and the reaction pressure is 0.1-0.2 MPa. The synthesis method of the present invention is easy to operate, the operating conditions are milder, and the product quality is higher. Compared with the prior art, the beneficial effects of the present invention are as follows: (1) An external strengthening unit is arranged outside the oxidation reactor of the present invention to crush and disperse the raw materials entering the oxidation reactor, improve the mass transfer effect between the reaction materials, and enhance the reaction efficiency. (2) An internal strengthening unit is arranged inside the oxidation reactor of the present invention and is used in cooperation with the shunt assembly, which can effectively crush and disperse the reaction raw materials, extend the reaction time at the same time, and improve the conversion rate of the raw materials. (3) An azeotropic distiller and a vacuum rectification column are respectively connected after the fixed bed reactor and the oxidation reactor of the present invention, which can respectively purify and refine the intermediate product dimethyl sulfide and the final product dimethyl sulfoxide, and improve the product quality. Description of the Drawings By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings: FIG. 1 is a schematic flow chart of a dimethyl sulfoxide synthesis system provided by Embodiment 1 of the present invention; FIG. 2 is a partial enlarged view of a static mixer provided by Embodiment 1 of the present invention; FIG. 3 is a schematic structural diagram of a shunt plate provided by Embodiment 1 of the present invention. Wherein: 1 - heating furnace; 2 - fixed bed reactor; 3 - azeotropic rectification column; 4 - oxidation reactor; 401 - shunt assembly; 4011 - shunt plate; 4012 - shunt hole; 5 - neutralization evaporation reactor; 6 - vacuum rectification column; 7 - waste water storage tank; 8 - incinerator; 9 - external strengthening unit; 901 - The first intensifying reactor; 902 - The second intensifying reactor; 903 - Connecting pipeline; 904 - Static mixer; 9041 - Spiral metal pipe; 9042 - Through hole; 10 - Built-in intensifying unit; 101 - The third intensifying reactor; 102 - The fourth intensifying reactor; 103 - Nozzle; 104 - Agitator; 11 - Hydrogen sulfide storage tank; 12 - Methanol storage tank; 13 - Nitrogen dioxide or oxygen storage tank. Detailed implementation manners The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific implementation manners. However, those skilled in the art will understand that the following described embodiments are some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase. In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations. In order to more clearly elaborate on the technical solutions in the present invention, the following will be described in the form of specific embodiments. Embodiment 1 Referring to FIGS. 1-3, a synthesis system for dimethyl sulfoxide according to an embodiment of the present invention includes a heating furnace 1, a fixed-bed reactor 2 for synthesizing dimethyl sulfide, an azeotropic distillation column 3 for refining crude dimethyl sulfide, an oxidation reactor 4 for synthesizing dimethyl sulfoxide, a neutralization evaporation reactor 5, and a vacuum distillation column 6 connected in sequence; the heating furnace 1 is connected to the feed inlet of the fixed-bed reactor 2; the azeotropic distillation column 3 is connected to the discharge port at the bottom of the fixed-bed reactor 2; the azeotropic distillation column 3 is connected to the oxidation reactor 4; wherein, an external strengthening unit 9 is provided outside the oxidation reactor 4, and the external strengthening unit 9 includes a first strengthening reactor 901 and a second strengthening reactor 902; the first strengthening reactor 901 is connected to the bottom of the azeotropic distillation column 3, the second strengthening reactor 902 is connected to a nitrogen dioxide or oxygen storage tank 13, and a communication pipeline 903 is provided between the first strengthening reactor 901 and the second strengthening reactor 902, and a static mixer 904 is provided in the communication pipeline 903. Referring to FIG. 2, the static mixer 904 in the present invention is a spiral metal tube 9041, and the spiral metal tube 9041 spirally extends along the longitudinal axis of the communication pipeline 903, and the spiral metal tube 9041 is adapted to the length of the communication pipeline 903. Specifically, a plurality of through holes 9042 are provided on the surface of the spiral metal tube 9041 of the present invention. In this embodiment, an internal strengthening unit 10 is provided inside the oxidation reactor 4. The internal strengthening unit 10 includes a third strengthening reactor 101 provided at the top of the oxidation reactor 4 and a fourth strengthening reactor 102 provided below the third strengthening reactor 101. The third strengthening reactor 101 is connected to the outlet of the communication pipeline 903, and the fourth strengthening reactor 102 is connected to the nitrogen dioxide or oxygen storage tank 13. Specifically, the outlet of the third strengthening reactor 101 is opposite to the outlet of the fourth strengthening reactor 102. A nozzle 103 is connected to the outlet of the third strengthening reactor 101, and a stirrer 104 is provided at the outlet of the fourth strengthening reactor 102. The side wall of the vacuum distillation column 6 of the present invention is connected to the third strengthening reactor 101 to recover unreacted raw materials. A flow splitting assembly 401 is provided directly below the internal strengthening unit 10 of the present invention. The flow splitting assembly 401 includes a plurality of flow splitting plates 4011 arranged in sequence from top to bottom, and the distance between adjacent two flow splitting plates 4011 gradually decreases. Specifically, referring to FIG. 3, flow splitting holes 4012 are provided on the flow splitting plates 4011, and the aperture of the flow splitting holes 4012 is 50-100 μm. The synthesis system of dimethyl sulfoxide of the present invention further includes an incinerator 8 and a wastewater storage tank 7; the incinerator 8 is respectively connected to the tops of the fixed-bed reactor 2, the azeotropic distillation column 3, the oxidation reactor 4, the neutralization evaporation reactor 5 and the vacuum distillation column 6 to remove the waste gas generated by the reaction; the wastewater storage tank 7 is connected to the vacuum distillation column 6 to store the wastewater. When the dimethyl sulfoxide synthesis system of the present invention is actually applied, it includes the following technological process: The hydrogen sulfide gas and methanol gas from the upstream hydrogen sulfide storage tank 11 and methanol storage tank 12 are preheated by the heating furnace 1; then they are introduced into the fixed-bed reactor 2 to react with the catalyst in the fixed-bed reactor 2 to generate crude dimethyl sulfide; the crude dimethyl sulfide enters the azeotropic distillation column 3 through the material outlet at the bottom of the fixed-bed reactor 2 to remove the moisture in the crude dimethyl sulfide by azeotropic distillation; the dimethyl sulfide after rectification and purification enters the external strengthening unit 9. At the same time, the nitrogen dioxide gas or oxygen in the nitrogen dioxide or oxygen storage tank 13 enters the external strengthening unit 9 for primary crushing, dispersion and mixing; then the mixed material is introduced into the oxidation reactor 4 for oxidation reaction to generate crude dimethyl sulfoxide; then the crude dimethyl sulfoxide enters the neutralization evaporation reactor 5 for neutralization, evaporation and concentration to remove salt; it is introduced into the vacuum distillation column 6 and made into finished dimethyl sulfoxide by vacuum distillation method; the waste gas generated during the reaction is subjected to high-temperature treatment by the incinerator 8, and at the same time the wastewater generated by the reaction is introduced into the wastewater storage tank 7 and transported to the subsequent wastewater treatment unit. Example 2 The difference between this example and Example 1 is only that the static mixer is a direct-current metal pipe. Example 3 The difference between this example and Example 1 is only that the distance between each shunt plate is equal. Example 4 The difference between this example and Example 1 is only that the aperture of the shunt hole is 10 mm. Comparative Example 1 The difference between this example and Example 1 is only that the external strengthening unit is not provided. Comparative Example 2 The difference between this example and Example 1 is only that the internal strengthening unit is not provided. Comparative Example 3 The difference between this example and Example 1 is only that the shunt component is not provided. Comparative Example 4 This example uses the prior art to directly oxidize the dimethyl sulfide generated from hydrogen sulfide gas and methanol gas with nitrogen dioxide to generate dimethyl sulfoxide. Experimental Example 1 The systems of Examples 1-4 and Comparative Examples 1-3 were respectively used to synthesize dimethyl sulfoxide. Hydrogen sulfide gas from a certain factory with a flow rate of 500 m3 / h and methanol gas with a flow rate of 1000 m3 / h were reacted with the catalyst γ-aluminum oxide to form dimethyl sulfide, and then oxidized with nitrogen dioxide gas to form dimethyl sulfoxide. The experimental data are as follows: Table 1 Experimental Data When dimethyl sulfoxide was synthesized by the prior art, the yield of the synthesized dimethyl sulfoxide was 88.2%, and the purity of dimethyl sulfoxide was about 80.5%. Among them, the reaction temperature was about 110°C and the reaction pressure was about 1.5 MPa. It can be seen from Table 1 that compared with the prior art, the yield and purity of dimethyl sulfoxide in each embodiment of the present invention were significantly improved, and the yield of dimethyl sulfoxide in Example 1 reached 99.9%, the purity reached 99.5%, and the reaction temperature and reaction pressure in Example 1 were significantly reduced, saving reaction energy consumption. It can be seen from Table 1 that Example 1 of the present invention is the optimal example. The system of this example uses a strengthening unit and an oxidation reaction kettle in combination, and the product yield and purity of the obtained dimethyl sulfoxide are significantly higher than those of the dimethyl sulfoxide synthesized in the prior art; at the same time, the reaction temperature and reaction pressure are significantly reduced, indicating that the combined setting method of the strengthening unit and the oxidation reaction kettle in Example 1 can achieve the optimal reaction effect. It can be seen that the preparation system of this example has low reaction energy consumption and good preparation effect. Among them, the yield and purity of dimethyl sulfoxide in Comparative Example 1 were lower than those in Example 1 because an external strengthening unit was not set in Comparative Example 1, and it could not fully crush and disperse the reaction raw materials entering the oxidation reaction kettle. It can be seen that Example 1 of the present invention improved the quality of dimethyl sulfoxide by setting an external strengthening unit outside the oxidation reaction tower. In short, compared with the prior art, the synthesis system of dimethyl sulfoxide of the present invention has a high raw material conversion rate and a high product yield, and is worthy of wide promotion and application. 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 them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A synthesis system for dimethyl sulfoxide, characterized in that, Comprising: A fixed-bed reactor for synthesizing dimethyl sulfide and an oxidation reactor for synthesizing dimethyl sulfoxide; An external strengthening unit is arranged outside the oxidation reactor. The external strengthening unit includes a first strengthening reactor and a second strengthening reactor. The first strengthening reactor is arranged above the second strengthening reactor. The first strengthening reactor is connected to the discharge port at the bottom end of the fixed-bed reactor. The second strengthening reactor is connected to a nitrogen dioxide or oxygen storage tank. A communication pipeline is arranged between the first strengthening reactor and the second strengthening reactor, and a static mixer is arranged in the communication pipeline.

2. The synthesis system of dimethyl sulfoxide according to claim 1, characterized in that, An internal strengthening unit is arranged inside the oxidation reactor. The internal strengthening unit includes a third strengthening reactor arranged at the top end of the oxidation reactor and a fourth strengthening reactor arranged below the third strengthening reactor. The third strengthening reactor is connected to the communication pipeline, and the fourth strengthening reactor is connected to the nitrogen dioxide or oxygen storage tank.

3. The synthesis system of dimethyl sulfoxide according to claim 2, characterized in that, The outlet of the third strengthening reactor is opposite to the outlet of the fourth strengthening reactor. A nozzle is connected to the outlet of the third strengthening reactor, and a stirrer is arranged at the outlet of the fourth strengthening reactor.

4. The synthesis system of dimethyl sulfoxide according to claim 2, wherein A flow splitting component is arranged directly below the internal strengthening unit. The flow splitting component includes a plurality of flow splitting plates arranged in sequence from top to bottom, and the interval distance between two adjacent flow splitting plates gradually becomes smaller.

5. The synthesis system of dimethyl sulfoxide according to claim 4, wherein, Flow splitting holes are arranged on the flow splitting plates, and the aperture of the flow splitting holes is 50 - 100 μm.

6. The synthesis system of dimethyl sulfoxide according to claim 1, characterized in that, The static mixer is a spiral metal pipe, and the spiral metal pipe spirally extends along the longitudinal axis of the communication pipeline, and the spiral metal pipe is adapted to the length of the communication pipeline.

7. The synthesis system of dimethyl sulfoxide according to claim 1, wherein A crude product outlet at the bottom end of the oxidation reactor is connected to a vacuum rectification tower, and the side wall of the vacuum rectification tower is connected to the third strengthening reactor to recover unreacted raw materials.

8. The synthesis system of dimethyl sulfoxide according to claim 7, characterized in that, It also includes a heating furnace, an azeotropic rectification tower, a neutralization evaporation reactor, an incinerator, and a waste water storage tank; The heating furnace is connected to the feed inlet of the fixed-bed reactor, and the heating furnace is used to preheat methanol and hydrogen sulfide; The azeotropic rectification tower is arranged between the fixed-bed reactor and the oxidation reactor, and the azeotropic rectification tower is used to refine the dimethyl sulfide coming out of the fixed-bed reactor; The neutralization evaporation reactor is arranged between the oxidation reactor and the azeotropic rectification tower to filter and remove impurities from dimethyl sulfoxide; The incinerator is respectively connected to the fixed-bed reactor, the azeotropic rectification tower, the oxidation reactor, the neutralization evaporation reactor, and the vacuum rectification tower; The waste water storage tank is connected to the vacuum rectification tower to store waste water.

9. A method for synthesizing dimethyl sulfoxide using the dimethyl sulfoxide synthesis system according to any one of claims 1-8, characterized in that, Including the following steps: Synthesizing dimethyl sulfide from methanol and hydrogen sulfide, and subjecting the dimethyl sulfide to an oxidation reaction with nitrogen dioxide or oxygen to generate dimethyl sulfoxide.

10. The synthesis method of dimethyl sulfoxide according to claim 9, characterized in that, The reaction temperature during the oxidation reaction is 30 - 50 °C, and the reaction pressure is 0.1 - 0.2 MPa.

Images