A distillation kettle for producing benzyl dichloride

Abstract

The present invention relates to the field of benzyl dichloride production, and in particular to a distillation kettle for benzyl dichloride production, comprising a kettle body, a plurality of partitions are installed at intervals inside the kettle body, the partitions seal and separate the kettle body into a plurality of chambers, a plurality of heat dissipation pipes are evenly arranged in the kettle body, the heat dissipation pipes respectively pass through the plurality of partitions in a sealed manner, and are used to complete the heating of a mixed liquid, and the flow direction of a circulating medium in the heat dissipation pipes is opposite to the flow direction of the mixed liquid in the kettle body; an adjusting mechanism is installed on the top of the kettle body, and is used to drive the partition between the first two chambers and the partition between the last two chambers to slide back and forth. The present invention uses continuous distillation to accurately control the dividing points of the front section, middle section and rear section of the distillation, on the one hand, to ensure the product purity of the benzyl dichloride obtained by distillation, and on the other hand, to avoid the loss of too much benzyl dichloride components, thereby improving product quality and production efficiency.

Description

Technical Field

[0001] The invention relates to the field of p-dichlorobenzyl production, in particular to a rectification kettle for p-dichlorobenzyl production. Background Art

[0002] During the chlorination reaction of p-dichlorobenzyl, a series of intermediates are produced, which usually include p-methylbenzyl chloride and some by-products. In order to ensure the purity of the product, the above products and by-products need to be further separated and purified.

[0003] At present, the commonly used distillation method is to use a distillation tower to carry out two stages of flash evaporation and rectification. In the flash evaporation stage, the raw material mixture undergoes simple distillation, and the collected mixture mainly includes p-xylene and p-methylbenzyl chloride. In the rectification stage, the slow distillation of p-dimethylbenzyl chloride is achieved by precise control of the heating temperature.

[0004] The above distillation method has the following disadvantages: 1. In the two stages of flash evaporation and distillation, the mixed liquid needs to be heated separately, resulting in energy waste; 2. The boundary point between the two stages of flash evaporation and distillation is relatively vague, resulting in part of the p-dichlorobenzyl product being evaporated in the flash evaporation stage, resulting in product loss, or the intermediate product in the flash evaporation stage is not completely removed, resulting in the p-dichlorobenzyl product in the distillation stage having a low purity, affecting the product quality. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a distillation kettle for producing benzyl dichloride, which solves the problem of energy waste by continuous distillation; and solves the problems of product quality and product loss by accurately controlling the distillation cutoff point through feedback regulation. It is specifically achieved by the following technical solutions:

[0006] The invention discloses a distillation kettle for producing benzyl dichloride, comprising a kettle body, a plurality of partitions are installed at intervals inside the kettle body, the partitions seal and separate the kettle body into a plurality of chambers, an exhaust pipe is installed on the top of each chamber, a first flow valve is installed on the bottom of the first chamber, a second flow valve is installed on the top of the last chamber, two adjacent chambers are connected through a circulation pipe, a liquid outlet of each chamber is located at the top, a liquid inlet is located at the bottom, and a liquid level sensor is fixedly installed on the top of the kettle body.

[0007] The exhaust pipe of the last chamber is communicated with the inlet of the cooling tower through a pipeline, and the outlet of the cooling tower is communicated with the first flow valve through a pipeline installed with a circulation pump.

[0008] A heat circulation mechanism is installed in the kettle body, and the heat circulation mechanism includes a heat dissipation pipe. A plurality of the heat dissipation pipes are evenly arranged in the kettle body. The heat dissipation pipes respectively and sealedly pass through a plurality of the partitions to complete the heating of the mixed liquid. The first end of the heat dissipation pipe is fixedly connected to the inlet of the heating unit, and the second end of the heat dissipation pipe is fixedly connected to the outlet of the heating unit through a pipeline installed with a pump body.

[0009] The flow direction of the circulating medium in the heat dissipation pipe is opposite to the flow direction of the mixed liquid in the kettle body;

[0010] An adjusting mechanism is installed on the top of the kettle body, which is used to drive the partition between the first two chambers and the partition between the last two chambers to slide back and forth. The adjusting mechanism includes a driving nut, the partition is drivingly connected to the driving nut, the driving nut is threadedly connected to the screw, the screw is coaxially fixed to the output end of the motor, and the motor is fixed to the kettle body.

[0011] The first flow valve, the second flow valve, the liquid level sensor, the circulation pump, the heating unit, and the motor are respectively connected to the controller signal.

[0012] Preferably, the thermal circulation mechanism also includes a diverter chamber, which is fixedly connected to the kettle body, and the side of the diverter chamber close to the first flow valve is fixedly connected to the liquid outlet pipe, and the liquid outlet pipe is fixedly connected to the inlet of the heating unit through a pipeline, and the outlet of the heating unit is fixedly connected to the liquid inlet pipe through a pipeline equipped with a pump body, and the liquid inlet pipe is fixedly connected to the side of the diverter chamber close to the second flow valve.

[0013] A diverter plate is vertically and sealedly installed in the diverter chamber, and the diverter plate seals and separates the diverter chamber into two chambers, one chamber is fixedly connected to the first ends of a plurality of the heat dissipation pipes, and the second ends of the heat dissipation pipes are fixedly connected to the other chamber.

[0014] Preferably, the adjustment mechanism also includes a rectangular window, the top of the kettle body is provided with the rectangular window, the top plate of the kettle body is provided with a mounting groove, a sliding plate sliding along the mounting groove is sealed and configured, the sliding plate completely blocks the rectangular window, the sliding plate is fixed to the partition, and the sliding plate is fixed to the drive nut.

[0015] Preferably, the sliding plate is fixed to a positioning plate, the positioning plate can be arranged between a laser and a receiver of a photoelectric sensor, the photoelectric sensor is mounted on the kettle body, and the photoelectric sensor is connected to the controller signal.

[0016] Preferably, a guide groove is provided on the side of the partition, and a guide block is provided in the guide groove for movement along the sealing sleeve, and the guide block is fixed to the side wall of the kettle body.

[0017] Preferably, the exhaust pipes at the top of the first chamber and the last chamber in the kettle are respectively connected to the inlet of the concentration measuring instrument, and the exhaust pipes at the top of the remaining chambers are respectively fixedly connected to the gas flow meter, and the concentration measuring instrument and the gas flow meter are respectively connected to the controller signal.

[0018] Preferably, the contour shape of the kettle body is a racetrack shape.

[0019] Preferably, the contour shape of the heat dissipation pipe is a runway shape which is the same as the contour shape of the kettle body.

[0020] After adopting the above technical solution, the beneficial effects of the present invention are:

[0021] 1. Through the continuous distillation of multiple chambers with the same heat source, the energy consumption of distillation in the front, middle and back sections is reduced, and the production cost is reduced;

[0022] 2. Through continuous distillation and combined with the concentration measurement of the evaporated gas and the heating temperature adjustment, the dividing points of the front section, middle section and back section of the distillation are accurately controlled, which, on the one hand, ensures the purity of the distilled benzyl chloride product and, on the other hand, avoids excessive loss of the dibenzyl chloride component.

[0023] 3. By monitoring the flow rate of the distillation gas in each chamber in the middle section, the circulation speed of the mixed liquid is controlled. Under the premise of ensuring the completion of the distillation, a higher efficiency distillation is achieved simultaneously, the distillation process of benzyl dichloride is optimized, and the production efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 This is the installation diagram of the distillation kettle for producing p-dichlorobenzyl;

[0026] Figure 2 This is a top view of the distillation kettle for producing p-dichlorobenzyl;

[0027] Figure 3 This is a top cutaway schematic diagram of a distillation reactor for producing p-dichlorobenzyl;

[0028] Figure 4 It is a side section schematic diagram of the distillation kettle body for producing benzyl dichloride;

[0029] Figure 5 for Figure 4 A partial enlarged view of

[0030] Figure 6 This is a transverse cross-sectional view of the distillation kettle body for producing benzyl dichloride.

[0031] Description of reference numerals:

[0032] 101-kettle body, 102-partition plate, 103-exhaust pipe, 104-first flow valve, 105-second flow valve, 106-liquid level sensor, 107-circulation pipe, 108-cooling tower, 109-circulation pump, 110-concentration measuring instrument, 111-gas flow meter;

[0033] 200-thermal circulation mechanism, 201-dividing chamber, 202-liquid outlet pipe, 203-heating unit, 204-liquid inlet pipe, 205-dividing plate, 206-heating pipe;

[0034] 300-adjusting mechanism, 301-rectangular window, 302-mounting slot, 303-sliding plate, 304-driving nut, 305-screw, 306-motor, 307-positioning plate, 308-photoelectric sensor, 309-guide slot, 310-guide block;

[0035] 400-Controller. DETAILED DESCRIPTION

[0036] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are not configured to limit the present invention. For those skilled in the art, the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by illustrating examples of the present invention.

[0037] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of the present invention. In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "installation" and "connection" 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 directly connected or indirectly connected. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0038] The embodiment of the present invention provides a distillation kettle for producing benzyl dichloride, see Figures 1 to 6, including a kettle body 101, the outline shape of the kettle body 101 is a runway type, a plurality of partitions 102 are installed at intervals inside the kettle body 101, and the inner cavity of the kettle body 101 is divided into a plurality of chambers, and an exhaust pipe 103 is installed on the top of each chamber for discharging the gas generated by distillation to the outside, a first flow valve 104 is installed at the bottom of the first chamber for conveying the mixed liquid to be distilled into the first chamber, and a second flow valve 105 is installed on the upper part of the last chamber for discharging the distilled liquid to the outside.

[0039] Two adjacent chambers are connected by a circulation pipe 107, and the first end of the circulation pipe 107 is fixedly connected to the top of the previous chamber, and the second end of the circulation pipe 107 is fixedly connected to the bottom of the next chamber. The reason for adopting this structure is that the components with higher temperatures in the mixed liquid in each chamber will be concentrated in the upper layer of the chamber due to their lower density, and the components with lower temperatures are concentrated in the bottom layer of the chamber. Therefore, they enter from the bottom and are discharged from the top, so that when the mixed liquid flows in each chamber connected in series, the temperature gradually increases, thereby realizing continuous distillation.

[0040] A liquid level sensor 106 is fixedly installed on the top of the kettle body 101. The liquid level sensor 106 is used to measure the liquid level in the kettle body 101, so that the liquid level is maintained above the second flow valve 105 and below the exhaust pipe 103, which can meet the discharge of the distilled gas and the circulation requirements of the mixed liquid.

[0041] The gas exhausted from the last chamber through the exhaust pipe 103 is transported to the inlet of the cooling tower 108 through a pipeline. After being cooled and liquefied by the cooling tower 108, it is transported from the outlet of the cooling tower 108 through a pipeline equipped with a circulation pump 109 to the first flow valve 104 to complete the cycle, thereby recovering the benzyl dichloride in the gas produced by the final distillation to avoid the loss of the product.

[0042] For further explanation of the present invention, see Figure 1 , 23. The heating of the mixed liquid in each chamber of the kettle body 101 is achieved by the thermal circulation mechanism 200. The thermal circulation mechanism 200 includes a diverter chamber 201, a liquid outlet pipe 202, a heating unit 203, a liquid inlet pipe 204, a diverter plate 205, and a heat dissipation pipe 206. The diverter chamber 201 is fixed to the first end of the kettle body 101, and the side of the diverter chamber 201 close to the first flow valve 104 is fixed and connected to the liquid outlet pipe 202. The liquid outlet pipe 202 is used to discharge the circulating medium in the diverter chamber 201. The diverter chamber 201 is fixed and connected to the inlet of the heating unit 203 through a pipeline equipped with a pump body. The heating unit 203 is used to complete the heating of the circulating medium. The outlet of the heating unit 203 is fixed and connected to the liquid inlet pipe 204 through a pipeline. The liquid inlet pipe 204 is fixed and connected to the side of the diverter chamber 201 close to the second flow valve 105. The liquid inlet pipe 204 is used to introduce the circulating medium into the diverter chamber 201.

[0043] A diverter plate 205 is vertically and sealedly installed in the diverter chamber 201, and the diverter plate 205 seals and separates the diverter chamber 201 into two chambers. One chamber is fixedly connected to the first ends of a plurality of heat dissipation tubes 206, and the second ends of the heat dissipation tubes 206 are fixedly connected to the other chamber. The contour shape of the plurality of heat dissipation tubes 206 is a runway shape that is the same as the contour shape of the kettle body 101. The heat dissipation tubes 206 are respectively and sealedly passed through a plurality of partitions 102 and distributed in each chamber of the kettle body 101 to complete the heating of the mixed liquid.

[0044] The above structure realizes synchronous and continuous heating of each chamber by the circulating medium. The heated circulating medium first enters the diverter chamber 201 through the liquid inlet pipe 204, and flows along the various chambers in the kettle body 101 through the heat dissipation pipe 206. The flow direction of the circulating medium in the heat dissipation pipe 206 is opposite to the flow direction in the chamber of the kettle body 101, that is, the circulating medium in the heat dissipation pipe 206 flows forward from the last chamber in the kettle body 101 in sequence, and finally returns to the diverter chamber 201 to be discharged outward through the liquid outlet pipe 202, and returns to the heating unit 203 for heating and circulation.

[0045] The above structure just makes the temperature of the mixed liquid in the kettle body 101 gradually rise when it flows in series between the chambers, thereby ensuring that the heating temperature in each chamber is continuous, which is convenient for determining the dividing point of the distillation of benzyl dichloride. In addition, through the recycling of the circulating medium, the residual energy in the circulating medium is effectively utilized, avoiding energy waste.

[0046] As another possible embodiment of the present invention, the partition 102 between the first two chambers and the partition 102 between the last two chambers in the kettle body 101 can be adjusted in position by an adjustment mechanism 300, and the adjustment mechanism 300 is installed on the top of the kettle body 101, and the adjustment mechanism 300 includes a rectangular window 301, a mounting groove 302, a sliding plate 303, a driving nut 304, a screw 305, a motor 306, a positioning plate 307, a photoelectric sensor 308, a guide groove 309, and a guide block 310. Figure 4 , 5 As shown in Figure 6, taking the partition 102 between the first two chambers as an example, a rectangular window 301 is provided on the top of the kettle body 101, and the rectangular window 301 can be connected with the first two chambers of the kettle body 101 respectively, and a mounting groove 302 is horizontally provided on the top plate of the kettle body 101. A sliding plate 303 that slides back and forth along its length direction is sealed in the mounting groove 302, and the sliding plate 303 can completely block the rectangular window 301. The lower surface of the sliding plate 303 is fixed to the partition 102, and the middle part of the upper surface of the sliding plate 303 is fixed to the driving nut 304. The driving nut 304 is threadedly connected to the screw 305. The first end of the screw 305 is coaxially fixed to the output end of the motor 306, the motor 306 is fixedly connected to the upper surface of the kettle body 101, and the second end of the screw 305 is rotatably installed on the upper surface of the kettle body 101.

[0047] The upper surface of the sliding plate 303 is also fixedly connected to the first end of the positioning plate 307. The second end of the positioning plate 307 can be configured between the laser and the receiver of the photoelectric sensor 308 and can block the light of the laser of the photoelectric sensor 308. The photoelectric sensor 308 is installed on the upper surface of the kettle body 101.

[0048] A guide groove 309 is provided on the side of the partition 102. A sealing sleeve in the guide groove 309 is provided with a guide block 310 that moves along the guide groove. The guide block 310 is fixed to the side wall of the kettle body 101. This structure is used to guide the partition 102 so that the partition 102 can slide more smoothly.

[0049] Of course, the partition 102 is also sealed and sleeved on the outer surfaces of the heat dissipation tubes 206 , so that the partition 102 can slide relative to the heat dissipation tubes 206 .

[0050] At the same time, the distilled gases discharged from the first chamber and the last chamber of the kettle body 101 through the exhaust pipe 103 on the top are respectively detected by the concentration measuring instrument 110, and the concentration measuring instrument 110 can detect the concentration of benzyl chloride in the gas. The gas in the first chamber is detected by the concentration measuring instrument 110 and discharged after exhaust gas treatment. The gas in the last chamber is transported to the entrance of the cooling tower 108 after being detected by the concentration measuring instrument 110; the exhaust pipes 103 on the top of the remaining chambers are respectively fixedly connected to the pipelines equipped with gas flow meters 111, and the gas flow meters 111 can detect the flow rate of the evaporated gas, so that the gas evaporated in the remaining chambers can be detected by the gas flow meters 111, and then condensed and collected to obtain the benzyl chloride product.

[0051] The concentration measuring instrument 110 includes a benzyl dichloride concentration meter and a measuring chamber. The probe of the benzyl dichloride concentration meter is arranged in the measuring chamber. The distilled gas discharged from the first chamber and the last chamber of the kettle body 101 through the exhaust pipe 103 at the top is respectively transported to the measuring chamber, thereby completing the measurement of the benzyl dichloride concentration.

[0052] In order to facilitate the coordinated work among the various mechanisms, the first flow valve 104, the second flow valve 105, the liquid level sensor 106, the circulation pump 109, the concentration meter 110, the gas flow meter 111, the heating unit 203, the motor 306, and the photoelectric sensor 308 are respectively connected to the controller 400 for signal connection. The controller 400 is used to collect signals and issue instructions to complete the mutual coordination among the various mechanisms.

[0053] The working principle and working process steps of the present invention are as follows:

[0054] S1. According to the empirical value, the heating unit 203 heats the medium to the target temperature value, and transports it to the diversion chamber 201 through the pump body, and then refluxes after heat dissipation through a plurality of heat dissipation pipes 206 arranged in the kettle body 101.

[0055] S2, opening the first flow valve 104 and the second flow valve 105, and conveying the mixed liquid to be distilled to the interior of the kettle 101 in a flow direction opposite to the medium in the heat dissipation pipe 206 to start distillation.

[0056] The temperature of the circulating medium in the heat dissipation pipe 206 will become lower and lower as the heat dissipation proceeds. The present invention sets the inlet of the mixed liquid in the chamber with the lowest temperature, so that the temperature of the mixed liquid gradually increases during the heating cycle, thereby effectively separating the impurity gases evaporated from the front and rear stages of the distillation, and ensuring the purity of the dibenzyl chloride in the middle stage of the distillation.

[0057] S3. Detect the height of the mixed liquid level in the kettle body 101 through the liquid level sensor 106. When the liquid level is lower than the top of the second flow valve 105 pipeline, close the second flow valve 105 and increase the first flow valve 104. When the liquid level is higher than the bottom of the exhaust pipe 103, close the first flow valve 104 and increase the second flow valve 105, so that the liquid level is always maintained between the top of the second flow valve 105 and the bottom of the exhaust pipe 103.

[0058] The height of the liquid level is maintained to achieve gas-liquid separation in each chamber in the kettle body 101, ensuring that all gases are discharged from the exhaust pipe 103 at the top of the chamber, and ensuring that the mixed liquid circulates smoothly.

[0059] S4. The concentration C1 of the benzyl chloride in the distilled gas in the first chamber of the kettle body 101 is detected by the concentration measuring instrument 110. When C1≥2%, the partition 102 between the first chamber and the second chamber is driven by the motor 306 to move toward the side close to the diversion chamber 201, and the positioning plate 307 is driven to move toward the photoelectric sensor 308 synchronously. When the positioning plate 307 triggers the photoelectric sensor 308, the controller 400 controls the heating unit 203 to reduce the heating temperature of the medium; when C1=0, the partition 102 between the first chamber and the second chamber is driven by the motor 306 to move toward the side away from the diversion chamber 201.

[0060] The first chamber in the kettle body 101 is used as the front section of distillation, and its purpose is to distill out impurities with a boiling point lower than that of p-dibenzyl chloride in the mixed liquid to avoid affecting the purity of the p-dibenzyl chloride product produced in the middle section of distillation. Therefore, there should be a small amount of p-dibenzyl chloride in the gas produced by distillation in this chamber, proving that p-dibenzyl chloride has begun to be evaporated. However, the concentration of p-dibenzyl chloride is controlled to be lower than 2% in order to avoid excessive p-dibenzyl chloride being evaporated, thereby causing loss and waste of the product.

[0061] When the partition 102 between the first chamber and the second chamber in the kettle body 101 moves toward the side close to the diversion chamber 201, the maximum heating temperature in the first chamber will decrease, thereby reducing the evaporation of benzyl dichloride, and vice versa, the evaporation of benzyl dichloride will increase. When the partition 102 moves to the extreme position, that is, when the photoelectric sensor 308 is triggered, if the detected concentration of benzyl dichloride is still not less than 2% at this time, it means that the temperature of the circulating medium is too high. At this time, the controller 400 controls the heating unit 203 to appropriately reduce the heating temperature of the medium to avoid the loss of benzyl dichloride product.

[0062] S5. The concentration C2 of the benzyl chloride in the distilled gas in the last chamber in the kettle body 101 is detected by the concentration measuring instrument 110. When C2≥5%, the partition 102 between the last two chambers is driven by the motor 306 to move toward the side close to the diversion chamber 201. At this time, the positioning plate 307 is driven to move toward the photoelectric sensor 308 synchronously. When the positioning plate 307 triggers the photoelectric sensor 308, the controller 400 controls the heating unit 203 to increase the heating temperature of the medium; when C2=0, the partition 102 between the last two chambers is driven by the motor 306 to move toward the side away from the diversion chamber 201.

[0063] The gas exhausted through the exhaust pipe 103 of the last chamber is input into the cooling tower 108 for liquefaction, and is transported back to the first flow valve 104 through a pipeline equipped with a circulation pump 109 and input into the first chamber for circulation distillation, thereby realizing the recovery and utilization of benzyl dichloride.

[0064] The last chamber in the kettle body 101 is used as the rear section of the distillation, and its purpose is to distill out the last p-dichlorobenzyl in the mixed liquid to avoid excessive loss of p-dichlorobenzyl product. Therefore, the gas evaporated in the chamber should contain some p-dichlorobenzyl gas, but the concentration of p-dichlorobenzyl should not be too high. If the concentration of p-dichlorobenzyl is too high, it is necessary to consider whether the p-dichlorobenzyl is completely distilled in the middle section of the distillation.

[0065] When it is detected that the concentration of benzyl dichloride evaporated in the chamber is greater than or equal to 5%, it means that a large amount of benzyl dichloride remains after the distillation of the middle section. Therefore, the partition 102 between the last two chambers is controlled by the motor 306 to move toward the side close to the diversion chamber 201, thereby increasing the distillation stroke and the maximum temperature of the middle section. When the partition 102 moves to the extreme position, that is, the photoelectric sensor 308 is triggered, if the detected concentration of benzyl dichloride is still greater than or equal to 5% at this time, it means that the temperature of the circulating medium is too low. At this time, the controller 400 controls the heating unit 203 to appropriately increase the heating temperature of the medium to avoid the loss of the benzyl dichloride product.

[0066] S6. Measure the flow rate of the gas distilled in each chamber in the middle section of the distillation (i.e., each chamber except the first chamber and the last chamber), set the flow rate of the gas distilled from the second to last chamber as Q1, and set the flow rate of the gas distilled from the third to last chamber as Q2. When Q1≥Q2, reduce the first flow valve 104 and the second flow valve 105 at the same time. When Q1<Q2*80%, increase the first flow valve 104 and the second flow valve 105 at the same time.

[0067] Under the premise of step S4 and step S5, the temperature of the middle section of the distillation is basically controlled within an appropriate range. At this time, the gas flow rate evaporated in the last two chambers of the middle section of the distillation is measured to determine the distillation completion of the middle section. When the distillation temperature in the last two chambers of the middle section of the distillation increases at any time and the amount of evaporated gas increases, the distillation may not be completely completed. Therefore, the first flow valve 104 and the second flow valve 105 are simultaneously adjusted to reduce the flow rate of the mixed liquid between the chambers, giving sufficient distillation time to ensure that the distillation of the mixed liquid is more thorough, so that the gas flow rate Q1 evaporated from the second to last chamber is slightly smaller than the gas flow rate Q2 evaporated from the third to last chamber; but Q1 cannot be much lower than Q2, because unlimited extension of the distillation time will reduce the overall distillation efficiency. Therefore, by setting an appropriate limit value, it is possible that a higher distillation efficiency can be achieved while ensuring the completion of the distillation of benzyl dichloride.

[0068] According to the embodiments of the present invention as described above, these embodiments do not describe all the details in detail, nor do they limit the invention to specific embodiments. Obviously, many modifications and changes can be made based on the above description. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can make good use of the present invention and the modified use based on the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A distillation kettle for producing benzyl dichloride, comprising a kettle body (101), characterized in that: A plurality of partitions (102) are installed at intervals inside the kettle body (101), and the partitions (102) seal and separate the kettle body (101) into a plurality of chambers. An exhaust pipe (103) is installed at the top of each chamber. A first flow valve (104) is installed at the bottom of the first chamber, and a second flow valve (105) is installed at the top of the last chamber. Two adjacent chambers are connected via a circulation pipe (107). The liquid outlet of each chamber is located at the top, and the liquid inlet is located at the bottom. A liquid level sensor (106) is fixedly installed at the top of the kettle body (101); The exhaust pipe (103) of the last chamber is connected to the inlet of the cooling tower (108) through a pipeline, and the outlet of the cooling tower (108) is connected to the first flow valve (104) through a pipeline equipped with a circulation pump (109); A heat circulation mechanism (200) is installed in the kettle body (101), and the heat circulation mechanism (200) comprises a heat dissipation pipe (206). A plurality of the heat dissipation pipes (206) are evenly arranged in the kettle body (101), and the heat dissipation pipes (206) respectively pass through a plurality of the partitions (102) in a sealed manner to complete the heating of the mixed liquid. A first end of the heat dissipation pipe (206) is fixedly connected to an inlet of a heating unit (203), and a second end of the heat dissipation pipe (206) is fixedly connected to an outlet of the heating unit (203) via a pipeline installed with a pump body; The flow direction of the circulating medium in the heat dissipation pipe (206) is opposite to the flow direction of the mixed liquid in the kettle body (101); An adjusting mechanism (300) is installed on the top of the kettle body (101) for driving the partition (102) between the first two chambers and the partition (102) between the last two chambers to slide back and forth, the adjusting mechanism (300) comprising a driving nut (304), the partition (102) being drivingly connected to the driving nut (304), the driving nut (304) being threadedly connected to a screw rod (305), the screw rod (305) being coaxially fixed to an output end of a motor (306), and the motor (306) being fixed to the kettle body (101); The first flow valve (104), the second flow valve (105), the liquid level sensor (106), the circulation pump (109), the heating unit (203), and the motor (306) are respectively connected to the controller (400) via signals.

2. A rectifying kettle for producing benzyl dichloride according to claim 1, characterized in that: The thermal cycle mechanism (200) further comprises a flow distribution chamber (201), the flow distribution chamber (201) being fixedly connected to the kettle body (101), the side of the flow distribution chamber (201) close to the first flow valve (104) being fixedly connected to a liquid outlet pipe (202), the liquid outlet pipe (202) being fixedly connected to an inlet of the heating unit (203) via a pipeline, the outlet of the heating unit (203) being fixedly connected to a liquid inlet pipe (204) via a pipeline equipped with a pump body, and the liquid inlet pipe (204) being fixedly connected to a side of the flow distribution chamber (201) close to the second flow valve (105); A flow divider plate (205) is vertically and sealedly installed in the flow divider chamber (201), and the flow divider plate (205) seals and separates the flow divider chamber (201) into two chambers, one chamber is fixedly connected to the first ends of a plurality of heat dissipation pipes (206), and the second ends of the heat dissipation pipes (206) are fixedly connected to the other chamber.

3. A distillation kettle for producing benzyl dichloride according to claim 1, characterized in that: The regulating mechanism (300) further comprises a rectangular window (301), the rectangular window (301) is provided on the top of the kettle body (101), a mounting groove (302) is provided on the top plate of the kettle body (101), a sliding plate (303) sliding along the mounting groove (302) is sealedly arranged inside the mounting groove (302), the sliding plate (303) completely blocks the rectangular window (301), the sliding plate (303) is fixed to the partition plate (102), and the sliding plate (303) is fixed to the driving nut (304).

4. A rectifying kettle for producing benzyl dichloride according to claim 3, characterized in that: The sliding plate (303) is fixed to the positioning plate (307), and the positioning plate (307) can be arranged between the laser and the receiver of the photoelectric sensor (308). The photoelectric sensor (308) is installed on the kettle body (101), and the photoelectric sensor (308) is connected to the controller (400) by signal.

5. A rectifying kettle for producing benzyl dichloride according to claim 4, characterized in that: A guide groove (309) is provided on the side of the partition plate (102), and a sealing sleeve in the guide groove (309) is provided with a guide block (310) that moves along the guide groove, and the guide block (310) is fixed to the side wall of the kettle body (101).

6. A distillation kettle for producing benzyl dichloride according to claim 1, characterized in that: The exhaust pipes (103) at the top of the first chamber and the last chamber in the kettle body (101) are respectively connected to the inlet of the concentration measuring instrument (110), and the exhaust pipes (103) at the top of the remaining chambers are respectively fixedly connected to the gas flow meter (111), and the concentration measuring instrument (110) and the gas flow meter (111) are respectively connected to the controller (400) for signal transmission.

7. A rectifying kettle for producing benzyl dichloride according to claim 1, characterized in that: The contour shape of the kettle body (101) is a racetrack shape.

8. A distillation kettle for producing benzyl dichloride according to claim 1, characterized in that: The contour shape of the heat dissipation pipe (206) is a racetrack shape which is the same as the contour shape of the kettle body (101).

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