A device and method for preparing dibasic acid esters

Abstract

The present invention relates to the technical field of dibasic ester preparation, and particularly to a dibasic ester esterification preparation device and method. A steam recovery pipe is connected to the kettle top of an esterification kettle. In an initial state, a sealing plate closes a sample outlet. When sampling is required, the sealing plate is rotated toward the inside of a transverse tube portion until one side of the sealing plate faces the steam outlet direction in the transverse tube portion. The slides on the sealing plates on both sides abut against each other to make the slides elastically retracted, driving the arc-shaped end plates to slide out along the arc-shaped end surfaces of the sealing plates. At this time, the arc-shaped end surfaces on one side of the sealing plates and the extended and slid-out arc-shaped end plates are used to guide the steam outlet in the transverse tube portion toward the sample outlet, so that the steam outlet can be efficiently guided to the sample outlet. By detecting the water content of the steam outlet in the sampling tube, the corresponding steam outlet channel is triggered to be connected. Compared with the existing method of uniformly collecting and re-distilling the evaporated hydrated methanol, the segmented collection and corresponding segmented recycling in different ways are more efficient.

Description

Technical Field

[0001] The present invention relates to the technical field of dibasic ester preparation, and in particular to a device and method for preparing dibasic esters by esterification. Background Art

[0002] Mixed dibasic acid dimethyl ester is a mixture of three dibasic acid esters, commonly known as nylon acid dimethyl ester. It is a combination of three environmentally friendly solvents: dimethyl adipate, dimethyl glutarate, and dimethyl succinate. It is an environmentally friendly high-boiling point solvent with good stability, safe use, and biodegradability, and is widely used. For the preparation of dibasic esters, the esterification process of mixed dibasic acids is often used, that is, mixed dibasic acids, catalysts and other raw materials are added to the esterification kettle for mixed esterification reaction. During the reaction, methanol is continuously added dropwise, and the dropwise addition rate and reaction temperature are controlled. At the same time, evaporated hydrated methanol (a mixture of methanol and water vapor) is continuously discharged to promote the esterification reaction to form esters. The hydrated methanol vapor can be passed to a distillation kettle or a distillation tower for distillation to remove water, and then the methanol is recovered for use in the next batch until the water content of the evaporated hydrated methanol meets the requirements, that is, the water content is very low, indicating that the esterification is nearing the end. After continuing to heat up to evaporate the residual methanol, the temperature in the esterification kettle begins to cool down, and the cooled reaction liquid is discharged into the neutralization kettle, and alkaline water is added to the neutralization kettle for neutralization. After neutralization, the remaining organic phase is subjected to reduced pressure distillation to produce the dibasic ester product.

[0003] There is an existing esterification separation device for the production of dimethyl dicarboxylate, such as that disclosed in Chinese patent document CN201815307U, which connects the gas phase outlet of the esterification reactor of dimethyl dicarboxylate to the esterification separation tower, so as to improve the esterification yield and reduce the burden of the methanol distillation process. However, in actual production, it is necessary to frequently detect the water content of the evaporated hydrated methanol to track and monitor the esterification process so as to adjust the process parameters in time and promote subsequent processes. In this regard, in the existing esterification preparation, the steam outlet is often sampled and the water content is detected by the classic Karl Fischer water determination method. However, since the steam outlet pipe is not suitable for designing a narrow one, there is a problem in how to frequently and evenly collect the steam outlet from a wider steam outlet pipe. In addition, the water content of the steam outlet changes greatly from large to small as the esterification progresses. In the existing esterification preparation, the method of uniformly collecting and distilling the steam outlet is not efficient. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to propose a device and method for preparing dibasic acid esters to solve the problems of how to frequently and evenly collect steam samples for testing and the low efficiency of uniformly collecting and distilling the steam in the existing dibasic acid ester preparation.

[0005] Based on the above purpose, the present invention provides a dibasic acid esterification preparation device, including an esterification kettle, wherein a stirring mechanism is provided in the esterification kettle:

[0006] The top of the esterification kettle is provided with a feeding port and a dripping pipe. The top of the esterification kettle is connected to a steam recovery pipe. The steam recovery pipe comprises a vertical pipe portion connected to the top of the esterification kettle and a horizontal pipe portion connected to one end of the vertical pipe portion. One end of the horizontal pipe portion is connected to a diversion pipe. A plurality of partitions are arranged in parallel at intervals in the diversion pipe, and the partitions are used to divide the diversion pipe into a plurality of separate steam outlet channels.

[0007] Sample outlets are symmetrically provided on both sides of the transverse tube portion, and a sampling tube is externally connected to the sample outlet. A sealing plate is rotatably connected to the sample outlet, and one side of the sealing plate is designed with an arc-shaped end face, and an arc-shaped end plate is slidably connected to the arc-shaped end face, and a slide is slidably connected to the other end face of the sealing plate. The slide and the arc-shaped end plate are transmission-connected. In the initial state, the other end face of the sealing plate is parallel to the tube wall of the transverse tube portion and closes the sample outlet, and the slide is in an initial pop-up state. When sampling is required, the sealing plate is rotated toward the inside of the transverse tube portion until one side of the sealing plate faces the steam outlet direction in the transverse tube portion, and the slides on the sealing plates on both sides abut against each other, so that the slide is elastically retracted, driving the arc-shaped end plate to slide out along the arc-shaped end face of the sealing plate, which is used to guide the steam outlet in the transverse tube portion to the sample outlet, and trigger the corresponding steam outlet channel to be connected by detecting the water content of the steam outlet in the sampling tube.

[0008] Preferably, the transverse tube is designed as a square tube, the slide plate is in the shape of a flat plate, and the sample outlets are symmetrically opened on the left and right sides or the upper and lower sides of the transverse tube.

[0009] Preferably, a gear is rotatably connected inside the sealing plate, and two sides of the gear are respectively meshed and connected with the inner side surface of the slide plate and the inner side surface of the arc-shaped end plate.

[0010] Preferably, one end of the slide away from the sealing plate is vertically connected to a stop block. When one side of the sealing plate faces the steam outlet direction in the transverse tube, the stop blocks on both sides of the slides abut against each other to make the slide into an elastically retracted state.

[0011] Preferably, a slot is provided on the inner wall of the transverse tube portion, and when the other end face of the sealing plate is parallel to the tube wall of the transverse tube portion and closes the sample outlet, the stop block is inserted into the slot to prevent the slide plate from elastically retracting.

[0012] Preferably, a connecting pipe is connected between the transverse pipe portion and the diversion pipe, the narrow end of the connecting pipe is connected to the transverse pipe portion, and the flared end of the connecting pipe is connected to the diversion pipe. Guide plates are rotatably connected on both sides of the narrow end of the connecting pipe, and are turned to the corresponding steam outlet channels through the guide plates on both sides, so as to guide the steam outlet in the transverse pipe portion to the corresponding steam outlet channels.

[0013] Preferably, an arc-shaped limit strip is connected to the expanded end of the connecting pipe, and the end of the guide plate away from the horizontal pipe portion is designed as a telescopic structure and elastically abuts against the arc-shaped limit strip.

[0014] Preferably, a sealing block is slidably connected to the inner wall of the narrow end of the connecting pipe. When the other end face of the sealing plate is parallel to the tube wall of the horizontal tube portion and closes the sample outlet, the steam outlet in the connecting pipe blows the sealing block so that the sealing block abuts against the end of the guide plate close to the horizontal tube portion.

[0015] The present invention also provides a dibasic acid esterification preparation method, comprising the following steps:

[0016] Methanol is first pumped into the esterification kettle, a stirring mechanism is turned on for stirring, and then a mixed dibasic acid raw material is added for mixing. After the addition of the raw materials is completed, the temperature in the esterification kettle is controlled to rise to dissolve the mixed dibasic acid and methanol. After the dissolution is completed, a catalyst is added, and the temperature in the esterification kettle is controlled to continue to rise to the reaction temperature. Then, methanol is started to be added dropwise into the kettle, the dropping rate and the reaction temperature are controlled, and the hydrated methanol evaporated from the kettle is continuously recovered through a steam recovery pipe. At the same time, the hydrated methanol flowing out of the steam recovery pipe is intermittently sampled through a sampling port, and the water content of the samples is detected.

[0017] In the early stage of the esterification reaction, the hydrated methanol discharged through one of the steam outlet channels is used for distillation to remove water and then recover methanol;

[0018] In the middle of the esterification reaction, when it is detected that the water content of the sampled hydrated methanol is less than the first preset value, another steam outlet channel is triggered to be opened, and the hydrated methanol discharged through the other steam outlet channel is led to the storage tank 1 for dissolving the next batch of mixed dibasic acid;

[0019] In the later stage of the esterification reaction, when it is detected that the water content of the sampled hydrated methanol is less than a second preset value, the remaining steam outlet channel is triggered to be opened, and the hydrated methanol discharged through the remaining steam outlet channel is led to the second storage tank for the next batch of dripping;

[0020] At the end of the esterification reaction, when it is detected that the water content of the sampled hydrated methanol is less than the third preset value, the temperature in the esterification kettle is controlled to continue to rise and the residual methanol is evaporated, and then the temperature in the esterification kettle is controlled to cool down, and the cooled reaction liquid is discharged into the neutralization kettle through the liquid outlet, and alkaline water is added to the neutralization kettle for neutralization. After neutralization, the remaining organic phase is subjected to reduced pressure distillation to produce a dibasic ester product.

[0021] The beneficial effects of the present invention are as follows: a steam recovery pipe is connected to the top of the esterification kettle. In the initial state, the end face of the other side of the sealing plate is parallel to the tube wall of the transverse tube part and closes the sample outlet. When sampling is required, the sealing plate is rotated toward the inside of the transverse tube part until one side of the sealing plate faces the steam outlet direction in the transverse tube part. The slides on the sealing plates on both sides abut against each other to make the slides elastically retracted, driving the arc-shaped end plate to slide out along the arc-shaped end face of the sealing plate. At this time, the arc-shaped end face on one side of the sealing plate and the extended arc-shaped end plate are used to guide the steam outlet in the transverse tube part to the sample outlet, which can efficiently guide the steam outlet to the sample outlet. By detecting the water content of the steam outlet in the sampling tube, the corresponding steam outlet channel is triggered to be connected. Compared with the existing method of uniformly collecting and re-distilling the evaporated hydrated methanol, the efficiency is higher through segmented collection and segmented recycling corresponding to different methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 It is a structural schematic diagram of the steam recovery pipe of the present invention;

[0025] Figure 3 This is a schematic structural diagram of a steam recovery pipe according to another embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the structure of the sampling tube of the present invention when sampling;

[0027] Figure 5 For the present invention Figure 4 A magnified schematic diagram of point A in the middle;

[0028] Figure 6 This is a schematic structural diagram of the sealing plate of the present invention when it starts to rotate;

[0029] Figure 7 For the present invention Figure 6 A magnified schematic diagram of point B in the middle;

[0030] Figure 8 This is a schematic structural diagram of the present invention when the sealing plate rotates to separate the abutment blocks on both sides;

[0031] Figure 9 For the present invention Figure 8 Enlarged schematic diagram of point C in the middle;

[0032] Figure 10 This is a structural schematic diagram of the sealing plate of the present invention when it rotates back to the initial state;

[0033] Figure 11 For the present invention Figure 10 The enlarged schematic diagram of point D in the middle;

[0034] Figure 12 For the present invention Figure 10 The enlarged schematic diagram of point E in the middle;

[0035] Figure 13 This is a schematic structural diagram of the guide plate of the present invention when it is rotated to the steam outlet channel at the lowest layer;

[0036] Figure 14 For the present invention Figure 13 Enlarged schematic diagram of point F in the middle.

[0037] The following are marked in the figure:

[0038] 1. Esterification kettle; 100. Feeding port; 101. Drip pipe; 102. Liquid outlet; 2. Steam recovery pipe; 21. Vertical pipe; 22. Horizontal pipe; 23. Diverter pipe; 24. Partition; 25. Steam outlet channel; 26. Connecting pipe; 3. Sample outlet; 4. Sampling tube; 5. Sealing plate; 51. Arc-shaped end plate; 52. Slide plate; 53. Stop block; 6. Gear; 7. Slot; 8. Guide plate; 9. Arc-shaped limit strip; 10. Sealing block. DETAILED DESCRIPTION

[0039] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific embodiments.

[0040] It should be noted that, unless otherwise defined, the technical or scientific terms used in the present invention should have the usual meanings understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0041] like Figure 1 、 Figure 2 、 Figure 4 、 Figure 5 、 Figure 10 、 Figure 11 As shown, a dibasic acid esterification preparation device includes an esterification kettle 1, the esterification kettle 1 is provided with a stirring mechanism, a feeding port 100 and a drip pipe 101 are provided on the top of the esterification kettle 1, and a steam recovery pipe 2 is connected to the top of the esterification kettle 1. The steam recovery pipe 2 includes a vertical pipe part 21 connected to the top of the esterification kettle 1 and a horizontal pipe part 22 connected to one end of the vertical pipe part 21. One end of the horizontal pipe part 22 is connected to a diversion pipe 23. A plurality of partitions 24 are arranged in parallel and at intervals in the diversion pipe 23. The partitions 24 divide the diversion pipe 23 into a plurality of separate steam outlet channels 25. Sample outlets 3 are symmetrically opened on both sides of the horizontal pipe part 22. A sampling tube 4 is externally connected to the sample outlet 3. A sealing plate 5 is rotatably connected to the sample outlet 3, and one side of the sealing plate 5 is designed with an arc-shaped end surface. , and an arcuate end plate 51 is slidably connected to the arcuate end surface, and a slide plate 52 is slidably connected to the other end surface of the sealing plate 5, and the slide plate 52 is transmission-connected to the arcuate end plate 51. In the initial state, the other end surface of the sealing plate 5 is parallel to the tube wall of the transverse tube portion 22 and closes the sample outlet 3. The slide plate 52 is in the initial pop-up state. When sampling is required, the sealing plate 5 is rotated toward the inside of the transverse tube portion 22 until one side of the sealing plate 5 faces the steam outlet direction in the transverse tube portion 22. The slide plates 52 on the sealing plates 5 on both sides abut against each other, so that the slide plate 52 is elastically retracted, driving the arcuate end plate 51 to slide out along the arcuate end surface of the sealing plate 5, and is used to guide the steam outlet in the transverse tube portion 22 to the sample outlet 3, and trigger the corresponding steam outlet channel 25 to be connected by detecting the water content of the steam outlet in the sampling tube 4.

[0042] The present invention is based on the existing dibasic acid esterification preparation process and equipment, including an esterification kettle 1, which is provided with a stirring mechanism. The stirring mechanism can adopt existing conventional structures such as turbine stirrers, anchor stirrers, and combined stirrers, and is driven to rotate by a driving device on the top of the kettle. The esterification kettle 1 can be designed as a dual heat exchange system with an inner coil and an outer jacket, that is, it includes a jacket on the outer periphery of the kettle and a spiral coil inside the kettle, which is conducive to efficient reaction temperature increase, temperature control, and rapid cooling after the reaction. The top of the esterification kettle 1 is provided with a feeding port 100 and a drip pipe 101 for feeding raw materials into the kettle and dripping methanol. The bottom of the esterification kettle 1 can also be provided with a liquid outlet 102 for discharging the reaction liquid and leading it to a neutralization kettle for alkaline water neutralization.

[0043] The top of the esterification kettle 1 is connected to a steam recovery pipe 2. The steam recovery pipe 2 is generally designed to be a thick pipe to facilitate the recovery of steam at the top of the kettle. The steam recovery pipe 2 includes a vertical pipe portion 21 connected to the top of the esterification kettle 1 and a horizontal pipe portion 22 connected to one end of the vertical pipe portion 21. One end of the horizontal pipe portion 22 is connected to a diversion pipe 23. A plurality of partitions 24 are arranged in parallel and at intervals in the diversion pipe 23. The partitions 24 divide the diversion pipe 23 into a plurality of separate steam outlet channels 25. In the present invention, Figure 4 、 Figure 5As shown, two partitions 24 are provided to separate three independent steam outlet channels 25 with a similar inner diameter to the transverse tube portion 22. Sample outlets 3 are symmetrically provided on both sides of the transverse tube portion 22. Specifically, the transverse tube portion 22 is a square tube design. The sample outlets 3 can be symmetrically provided on the left and right sides or the upper and lower sides of the transverse tube portion 22. A sampling tube 4 is externally connected to the sample outlet 3. A sealing plate 5 is rotatably connected to the sample outlet 3. The length and width of the sealing plate 5 match the length and width of the sample outlet 3. One side of the sealing plate 5 is designed as an arc-shaped end face, and an arc-shaped end plate 51 is fitted and slidably connected to the arc-shaped end face. A slide plate 52 is fitted and slidably connected to the other end face of the sealing plate 5. Specifically, the slide plate 52 can be a flat plate. The slide plate 52 is transmission-connected to the arc-shaped end plate 51. In the initial state, as shown Figure 10 、 Figure 11 As shown, the other side end surface of the sealing plate 5 is parallel to the tube wall of the horizontal tube portion 22 and closes the sample outlet 3, and the slide plate 52 is in the initial pop-up state. Specifically, the slide plate 52 and the other side end surface of the sealing plate 5 can be elastically connected by an elastic member such as a spring, so that the slide plate 52 is in the initial pop-up state. When sampling is required, Figure 4 、 Figure 5 As shown, by rotating the sealing plate 5 toward the inside of the transverse tube portion 22 until one side of the sealing plate 5 faces the steam outlet direction of the transverse tube portion 22, the slide plates 52 on the sealing plates 5 on both sides abut against each other, so that the slide plates 52 are elastically retracted, driving the arc-shaped end plates 51 to slide out along the arc-shaped end surfaces of the sealing plates 5. At this time, the arc-shaped end surface on one side of the sealing plate 5 and the arc-shaped end plates 51 that extend and slide out are used to guide the steam outlet in the transverse tube portion 22 to the sample outlet 3. Since the sealing plate 5 and the arc-shaped end plates 51 are symmetrically arranged on the left and right sides or the upper and lower sides of the transverse tube portion 22, they almost completely cover the entire transverse tube portion 22, and can efficiently guide the steam outlet to the sample outlet 3. Compared with the existing method of opening a sampling port in a wider steam outlet pipe, Holes are used for sampling. Since the sampling holes are only distributed on the inner wall of the steam outlet pipe, only the steam flowing close to the inner wall is sampled, and the sampling efficiency is not high. At the same time, considering the precipitation of water vapor in hydrated methanol and the interference of factors such as the condensation of methanol close to the pipe wall, the sampling holes on the inner wall of the steam outlet pipe affect the uniformity of sampling and the detection of the actual water content. The steam in the sampling pipe 4 can be tested for water content by Karl Fischer water determination, which is fast and the results are accurate. The interval time or frequency of sampling detection can be set according to the actual process requirements to realize the tracking and monitoring of the esterification process. After the sampling and detection, the sealing plate 5 rotates back to the initial state of the closed sample outlet 3. During the rotation, if Figure 4 、 Figure 6 、 Figure 8 、 Figure 10 As shown, the slides 52 on the two side sealing plates 5 gradually separate, so that the slides 52 return to the initial pop-up state, driving the arc-shaped end plates 51 to slide and return along the arc-shaped end surfaces of the sealing plates 5, thereby preventing the extended arc-shaped end plates 51 from abutting against the sample outlet 3 and affecting the sealing plates 5 from rotating to close the sample outlet 3;

[0044] In the esterification preparation process of the present invention, methanol is first pumped into the esterification kettle 1, the stirring mechanism is turned on for stirring, and then the mixed dibasic acid raw material is added for mixing. After the mixing is completed, the temperature in the esterification kettle 1 is controlled to rise to dissolve the mixed dibasic acid and methanol. After the dissolution is completed, a catalyst is added. The catalyst is a conventional concentrated sulfuric acid, solid acid, etc. After the temperature in the esterification kettle 1 is controlled to continue to rise to the reaction temperature, methanol is started to be added dropwise to the kettle, the dropping rate and reaction temperature are controlled, and the water evaporated in the kettle is continuously recovered through the steam recovery pipe 2. At the same time, the hydrated methanol flowing out of the steam recovery pipe 2 is intermittently sampled through the sampling port 3, and the water content is detected. In the early stage of the esterification reaction, the water content of the hydrated methanol is high. The hydrated methanol that has discharged steam through one of the steam outlet channels 25 is used to be discharged to the distillation kettle or the distillation tower for distillation to remove water, and then the methanol is recovered. In the middle stage of the esterification reaction, the water content of the hydrated methanol continues to decrease. When it is detected that the water content of the sampled hydrated methanol is less than the first preset value, another steam outlet channel 25 is triggered to be opened, and another steam outlet channel 2 is used to be discharged through the other steam outlet channel 2 The hydrated methanol with steam is passed to the storage tank 1 for dissolving the mixed dibasic acid in the next batch. When the water content of the hydrated methanol is further reduced in the late stage of the esterification reaction, the water content of the sampled hydrated methanol is detected to be less than the second preset value, which triggers the conduction of the last remaining steam outlet channel 25. The hydrated methanol with steam passing through the last remaining steam outlet channel 25 is passed to the storage tank 2 for the next batch of dropwise addition. When the water content of the hydrated methanol is further reduced in the late stage of the esterification reaction, the water content of the sampled hydrated methanol is detected to be less than the second preset value. At the third preset value, the temperature in the esterification kettle 1 is controlled to continue to rise and the residual methanol is evaporated, and then the temperature in the esterification kettle 1 is controlled to cool down, and the cooled reaction liquid is discharged into the neutralization kettle through the liquid outlet 102, and alkaline water is added to the neutralization kettle for neutralization. After neutralization, the remaining organic phase is subjected to reduced pressure distillation to produce the dibasic ester product, thereby completing the entire dibasic acid esterification preparation process. Compared with the existing method of uniformly collecting and re-distilling the evaporated hydrated methanol, the efficiency is higher through segmented collection and corresponding segmented recycling in different ways.

[0045] In an embodiment of the present invention, optionally, Figure 1 、 Figure 2 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 、 Figure 11As shown, a gear 6 is rotatably connected inside the sealing plate 5, and both sides of the gear 6 are respectively meshed with the inner side surface of the slide plate 52 and the inner side surface of the arc-shaped end plate 51. Specifically, the inner side surface of the slide plate 52 and the inner side surface of the arc-shaped end plate 51 may be provided with tooth-like protrusions meshed with the gear 6, similar to the tooth structure of the existing conventional rack, so that when the slide plate 52 slides along the other side end surface of the sealing plate 5, it drives the gear 6 to rotate, thereby transmitting the synchronous movement of the arc-shaped end plate 51.

[0046] In an embodiment of the present invention, optionally, Figure 1 、 Figure 2 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 As shown, the end of the slide plate 52 away from the sealing plate 5 is vertically connected to a stop block 53, so that when the sealing plate 5 rotates toward the transverse tube portion 22, the stop block 53 can more efficiently abut against each other, ensuring that the slide plates 52 on both sides of the sealing plates 5 press against each other, until one side of the sealing plate 5 faces the steam outlet direction in the transverse tube portion 22, the stop blocks 53 on the two sides of the slide plates 52 abut against each other, so that the slide plate 52 is in an elastically retracted state.

[0047] In an embodiment of the present invention, optionally, Figure 1 、 Figure 2 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 As shown, a slot 7 is provided on the inner wall of the transverse tube portion 22, and the other end face of the sealing plate 5 is parallel to the tube wall of the transverse tube portion 22 and closes the sample outlet 3. The slide plate 52 is in the initial pop-up state. Figure 10 、 Figure 11 As shown, the slide plate 52 is located on the inner side of the tube wall of the transverse tube portion 22, and the stop block 53 is inserted into the slot 7. Even if the steam flow out of the transverse tube portion 22 is large, it can ensure that the slide plate 52 cannot be elastically retracted, thereby avoiding the initial stage of the next rotation of the sealing plate 5 toward the transverse tube portion 22. Due to the small sliding and retraction of the slide plate 52, the arc-shaped end plate 51 slides out, which in turn affects the rotation of the sealing plate 5. At the same time, the firm attachment of the slide plate 52 is also beneficial to the sealing of the sample outlet 3 and prevents the sealing plate 5 from rotating back into the sampling tube 4.

[0048] Among them, sealing strips can be attached around the sealing plate 5. When the sealing plate 5 closes the sample outlet 3, the sealing strips around it can elastically abut against the gap between the sealing plate 5 and the sample outlet 3 to achieve a better sealing effect. Even if a small amount of hydrated methanol seeps into the sampling tube 4, it will have little effect on the preparation and use of the dibasic acid ester preparation device.

[0049] In an embodiment of the present invention, optionally, Figure 1 、 Figure 2 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 、 Figure 13 As shown, a connecting pipe 26 is connected between the transverse pipe portion 22 and the diverter pipe, the narrow end of the connecting pipe 26 is connected to the transverse pipe portion 22, and the flared end of the connecting pipe 26 is connected to the diverter pipe 23. The two sides of the narrow end of the connecting pipe 26 are rotatably connected with guide plates 8. The diverter pipe 23 can also be designed to be a square tube shape, and is divided into three layers of independent steam outlet channels 25 above and below. The guide plate 8 can be designed horizontally, and the front and rear sides of the guide plate 8 can be respectively provided with sealing strips, and are abutted against the front and rear sides of the connecting pipe 26 through the sealing strips. When the guide plates 8 on both sides rotate up and down, that is, when the guide plates 8 on both sides turn to the corresponding steam outlet channels 25, they are used to guide the steam outlet in the transverse pipe portion 22 to the corresponding steam outlet channels 25.

[0050] In an embodiment of the present invention, optionally, Figure 1 、 Figure 2 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 、 Figure 13 As shown, an arc-shaped limit strip 9 is connected to the flared end of the connecting tube 26, and the arc-shaped limit strip 9 can be respectively connected to the front and rear sides of the connecting tube 26. The end of the guide plate 8 away from the cross tube portion 22 is designed as a telescopic structure and elastically abuts against the arc-shaped limit strip 9, which is similar to the existing conventional elastic telescopic rod structure, except that the telescopic rod is replaced by a plate-shaped structure. When the guide plates 8 on both sides rotate up and down, the telescopic end of the guide plate 8 always abuts against the arc-shaped limit strip 9, thereby connecting with one end of the partition 24, so as to efficiently guide the steam outlet to the corresponding steam outlet channel 25.

[0051] Among them, such as Figure 1 、 Figure 2As shown, the rotating connection of the sealing plate 5 and the rotating connection of the guide plate 8 can be provided with a rotating shaft to realize the rotation connection with the pipe wall. Specifically, one end of each rotating shaft can be individually controlled by an existing conventional rotary cylinder to realize the rotation driving action. As another embodiment, Figure 1 、 Figure 3 As shown, one end of the rotating shaft of the guide plate 8 can be connected to a gear part respectively, and the guide plates 8 on both sides can be driven to move in the same direction through a gear set. One end of the rotating shaft of the sealing plate 5 can be connected to a gear part respectively, and the two gear parts are meshed and connected through a slide, and then the sealing plates 5 on both sides are driven to rotate in the opposite direction through the lateral movement of the slide.

[0052] In an embodiment of the present invention, optionally, Figure 1 、 Figure 2 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 、 Figure 12 、 Figure 13 、 Figure 14 As shown, a sealing block 10 is slidably connected to the inner wall of the narrow end of the connecting tube 26. The sealing block 10 can be made of conventional flexible materials such as sealing rubber. When the other end surface of the sealing plate 5 is parallel to the wall of the horizontal tube portion 22 and closes the sample outlet 3, as shown in FIG. Figure 12 As shown, the steam outlet in the connecting pipe 26 blows the sealing block 10 so that the sealing block 10 abuts against the end of the guide plate 8 close to the transverse tube portion 22, thereby helping to block the gap between the end of the guide plate 8 close to the transverse tube portion 22 and the connecting pipe 26, and preventing the steam from leaking toward the adjacent steam outlet channel 25. However, the continuous pressure of the sealing block 10 is obviously not conducive to the flexible rotation of the guide plate 8. When the sealing plate 5 rotates toward the transverse tube portion 22, even if the slides 52 abutting on both sides do not completely block the steam outlet toward the connecting pipe 26, the steam outlet flow rate and pressure toward the connecting pipe 26 will also drop significantly, and then the sealing block 10 will not press tightly against the guide plate 8. Figure 14 As shown, it is beneficial to the flexible rotation adjustment of the guide plate 8.

[0053] The present invention also provides a dibasic acid esterification preparation method, comprising the following steps:

[0054] Methanol is first pumped into the esterification kettle 1, a stirring mechanism is turned on for stirring, and then a mixed dibasic acid raw material is added for mixing. After the feeding is completed, the temperature in the esterification kettle 1 is controlled to rise to dissolve the mixed dibasic acid and methanol. After the dissolution is completed, a catalyst is added, and the temperature in the esterification kettle 1 is controlled to continue to rise to the reaction temperature. Then, methanol is started to be added dropwise into the kettle, the dropping rate and the reaction temperature are controlled, and the hydrated methanol evaporated in the kettle is continuously recovered through the steam recovery pipe 2. At the same time, the hydrated methanol flowing out of the steam recovery pipe 2 is intermittently sampled through the sampling port 3, and the water content of the samples is detected;

[0055] In the early stage of the esterification reaction, the hydrated methanol discharged through one of the steam outlet channels 25 is used for distillation to remove water and then recover methanol;

[0056] In the middle of the esterification reaction, when the water content of the sampled hydrated methanol is detected to be less than the first preset value, another steam outlet channel 25 is triggered to be opened, and the hydrated methanol discharged through the other steam outlet channel 25 is led to the storage tank 1 for dissolving the next batch of mixed dibasic acid;

[0057] In the later stage of the esterification reaction, when it is detected that the water content of the sampled hydrated methanol is less than a second preset value, the remaining steam outlet channel 25 is triggered to be opened, and the hydrated methanol discharged through the remaining steam outlet channel 25 is led to the storage tank 2 for the next batch of dripping;

[0058] At the end of the esterification reaction, when it is detected that the water content of the sampled hydrated methanol is less than the third preset value, the temperature in the esterification kettle 1 is controlled to continue to rise and the residual methanol is evaporated, and then the temperature in the esterification kettle 1 is controlled to cool down, and the cooled reaction liquid is discharged into the neutralization kettle through the liquid outlet 102, and alkaline water is added to the neutralization kettle for neutralization. After neutralization, the remaining organic phase is subjected to reduced pressure distillation to produce a dibasic ester product, thereby completing the entire dibasic acid esterification preparation process. Compared with the existing method of uniformly collecting and re-distilling the evaporated hydrated methanol, the efficiency is higher through segmented collection and corresponding segmented recycling in different ways.

[0059] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Within the scope of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. A dibasic acid esterification preparation device, comprising an esterification kettle (1), wherein the esterification kettle (1) is provided with a stirring mechanism, characterized in that: The top of the esterification kettle (1) is provided with a feeding port (100) and a dripping pipe (101); the top of the esterification kettle (1) is connected to a steam recovery pipe (2); the steam recovery pipe (2) comprises a vertical pipe portion (21) connected to the top of the esterification kettle (1) and a horizontal pipe portion (22) connected to one end of the vertical pipe portion (21); one end of the horizontal pipe portion (22) is connected to a diversion pipe (23); a plurality of partitions (24) are arranged in parallel and at intervals in the diversion pipe (23); the partitions (24) divide the diversion pipe (23) into a plurality of separate steam outlet channels (25); Sample outlets (3) are symmetrically provided on both sides of the transverse tube portion (22), and a sampling tube (4) is externally connected to the sample outlet (3). A sealing plate (5) is rotatably connected to the sample outlet (3). One side of the sealing plate (5) is designed as an arc-shaped end face, and an arc-shaped end plate (51) is slidably connected to the arc-shaped end face. A slide plate (52) is slidably connected to the other side end face of the sealing plate (5). The slide plate (52) is transmission-connected to the arc-shaped end plate (51). In the initial state, the other side end face of the sealing plate (5) is parallel to the tube wall of the transverse tube portion (22) and closes the sample outlet (3). The slide plate (5 2) is in the initial pop-up state. When sampling is required, the sealing plate (5) rotates toward the inside of the transverse tube (22) until one side of the sealing plate (5) faces the steam outlet direction of the transverse tube (22). The slides (52) on the sealing plates (5) on both sides abut against each other, so that the slides (52) are in an elastically retracted state, driving the arc-shaped end plate (51) to slide out along the arc-shaped end surface of the sealing plate (5), so as to guide the steam outlet in the transverse tube (22) to the sampling port (3). By detecting the water content of the steam outlet in the sampling tube (4), the corresponding steam outlet channel (25) is triggered to be connected.

2. The dibasic acid esterification preparation device according to claim 1, characterized in that: The transverse tube portion (22) is designed as a square tube, the slide plate (52) is in the shape of a flat plate, and the sample outlets (3) are symmetrically opened on the left and right sides or the upper and lower sides of the transverse tube portion (22).

3. The dibasic acid esterification preparation device according to claim 1, characterized in that: A gear (6) is rotatably connected inside the sealing plate (5), and two sides of the gear (6) are respectively meshed and connected with the inner side surface of the slide plate (52) and the inner side surface of the arc-shaped end plate (51).

4. The dibasic acid esterification preparation device according to claim 1, characterized in that: One end of the slide plate (52) away from the sealing plate (5) is vertically connected to a stop block (53). When one side of the sealing plate (5) faces the steam outlet direction in the transverse tube portion (22), the stop blocks (53) on both sides of the slide plates (52) abut against each other, so that the slide plates (52) are in an elastically retracted state.

5. The dibasic acid esterification preparation device according to claim 4, characterized in that: A slot (7) is provided on the inner wall of the transverse tube portion (22). When the other end face of the sealing plate (5) is parallel to the tube wall of the transverse tube portion (22) and closes the sample outlet (3), the stop block (53) is inserted into the slot (7) to prevent the slide plate (52) from elastically retracting.

6. The dibasic acid esterification preparation device according to claim 1, characterized in that: A connecting pipe (26) is connected between the transverse pipe portion (22) and the diverter pipe (23); a narrow end of the connecting pipe (26) is connected to the transverse pipe portion (22); an expanded end of the connecting pipe (26) is connected to the diverter pipe (23); guide plates (8) are rotatably connected on both sides of the narrow end of the connecting pipe (26); the guide plates (8) on both sides are used to guide the steam out of the transverse pipe portion (22) to the corresponding steam outflow channel (25).

7. The dibasic acid esterification preparation device according to claim 6, characterized in that: An arc-shaped limit strip (9) is connected to the expanded end of the connecting pipe (26), and the end of the guide plate (8) away from the transverse pipe portion (22) is designed as a telescopic structure and elastically abuts against the arc-shaped limit strip (9).

8. The dibasic acid esterification preparation device according to claim 6, characterized in that: A sealing block (10) is slidably connected to the inner wall of one end of the narrow opening of the connecting pipe (26). When the other end surface of the sealing plate (5) is parallel to the wall of the transverse pipe portion (22) and closes the sample outlet (3), the steam in the connecting pipe (26) blows the sealing block (10) so that the sealing block (10) abuts against one end of the guide plate (8) close to the transverse pipe portion (22).

9. A method for preparing a dibasic acid ester by esterification, the method using the dibasic acid ester preparation device according to any one of claims 1 to 8, characterized in that: The following steps are involved: Methanol is first pumped into the esterification kettle (1), a stirring mechanism is turned on for stirring, and then a mixed dibasic acid raw material is added for mixing. After the addition of the raw materials is completed, the temperature in the esterification kettle (1) is controlled to rise to dissolve the mixed dibasic acid and methanol. After the dissolution is completed, a catalyst is added, and the temperature in the esterification kettle (1) is controlled to continue to rise to the reaction temperature. Then, methanol is added dropwise to the kettle, the dropping rate and the reaction temperature are controlled, and the hydrated methanol evaporated from the kettle is continuously recovered through the steam recovery pipe (2). At the same time, the hydrated methanol flowing out of the steam recovery pipe (2) is intermittently sampled through the sample outlet (3), and the water content of the sample is detected. In the early stage of the esterification reaction, the hydrated methanol discharged through one of the steam outlet channels (25) is used for distillation to remove water and then recover methanol; In the middle stage of the esterification reaction, when it is detected that the water content of the sampled hydrated methanol is less than a first preset value, another steam outlet channel (25) is triggered to be opened, and the hydrated methanol discharged through the other steam outlet channel (25) is led to the storage tank 1 for dissolving the next batch of mixed dibasic acid; In the later stage of the esterification reaction, when it is detected that the water content of the sampled hydrated methanol is less than a second preset value, the remaining steam outlet channel (25) is triggered to be turned on, and the hydrated methanol discharged through the remaining steam outlet channel (25) is led to the second storage tank for the next batch of dripping; At the end of the esterification reaction, when it is detected that the water content of the sampled hydrated methanol is less than a third preset value, the temperature in the esterification kettle (1) is controlled to continue to rise and the residual methanol is evaporated, and then the temperature in the esterification kettle (1) is controlled to cool down, and the cooled reaction liquid is discharged into the neutralization kettle through the liquid outlet (102), and alkaline water is added to the neutralization kettle for neutralization. After neutralization, the remaining organic phase is subjected to reduced pressure distillation to produce a dibasic ester product.

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