Methylamine rectification equipment, separation and purification components, and purification process

Abstract

The present invention discloses a methylamine rectification device, a separation and purification component, and a purification process, which relate to the technical field of methylamine processing. The methylamine rectification device includes a tower body. A skirt support is provided at the bottom of the tower body. A manhole is opened on the side of the skirt support. A liquid discharge pipe is provided at the bottom of the tower body. A ventilation hole is provided on the side of the skirt support. A steam inlet pipe is provided at the bottom side of the side of the tower body. A liquid inlet pipe is provided on the side of the tower body. A reflux pipe and a tower top suspension column are respectively provided on both sides at the top of the side of the tower body. A steam outlet pipe is provided at the top end of the tower body. A gas-liquid separator is provided at the top side inside the tower body. A tray assembly is vertically and staggeredly provided inside the tower body. The present invention realizes the adjustment of the distance between trays to reduce the risk of liquid flooding, and timely monitors and adjusts process parameters when liquid leakage occurs on the trays. In addition, it is convenient to adjust the flow rate of the liquid on the trays according to production needs, and it is convenient to intervene in blockage removal in time when the trays are blocked.

Description

Technical Field

[0001] The present invention relates to the technical field of methylamine processing, and specifically to a methylamine rectification device, a separation and purification component, and a purification process. Background Art

[0002] Methylamine is a class of important organic compounds, mainly including monomethylamine, dimethylamine, and trimethylamine. Methylamine rectification is a key link in the production process of methylamine, aiming to separate the mixture after the methylamine synthesis reaction into high-purity products such as monomethylamine, dimethylamine, and trimethylamine. In the prior art, methylamine rectification equipment usually includes a deammoniation tower (Tower I), an extraction tower (Tower II), a dehydration tower (Tower III), a separation tower (Tower IV), and a methanol recovery tower (Tower V). The dehydration tower is a crucial link in the methylamine rectification process, mainly used to separate water and organic components such as monomethylamine and dimethylamine in the feed.

[0003] Chinese Patent with application number 2017207591622 discloses a tray-type rectification tower, which includes a tower body and a number of trays. The trays divide the inside of the tower body into several rectification chambers, and a pressure regulating mechanism is arranged between the rectification chambers. The pressure regulating mechanism includes a horizontal pipe and branch pipes; one end of the horizontal pipe is connected to the rectification chamber, and one end of the branch pipe is connected to another rectification chamber; the other end of the branch pipe is connected to the horizontal pipe; a slider and an elastic member are also arranged in the horizontal pipe. One end of the elastic member is fixed at the end of the horizontal pipe far from the rectification chamber, and the other end is fixedly connected to the slider; in the initial state, the elastic member is in a relaxed state, the slider is located at the connection between the branch pipe and the horizontal pipe, and the branch pipe and the horizontal pipe are not connected.

[0004] However, in the actual use process of the above prior art, the tray spacing cannot be adjusted as needed. If the tray spacing is small, when the gas-liquid flow rate in the tower exceeds the bearing capacity range of the trays, flooding will occur, resulting in poor quality of the top product. Moreover, when the gas-liquid flow rate in the tower is lower than the lower limit of the bearing capacity of the trays, a leakage phenomenon will occur, causing the liquid to flow directly through the holes in the trays, resulting in insufficient gas-liquid contact and a decrease in mass transfer and heat transfer efficiency.

[0005] In addition, during the dehydration process using a plate rectification tower, if the liquid on the trays flows into the downcomer too quickly, it will lead to short and insufficient contact time between the steam and the liquid, reducing the mass transfer efficiency. In addition, the raw materials or reaction products in the methylamine production process contain impurities, polymers, or solid particles, etc. These substances are likely to accumulate on the trays, causing blockage of the trays, and further making the gas-liquid contact uneven and the mass transfer and heat transfer effects poor. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the existing defects, and provide a methylamine rectification device, a separation and purification component and a purification process, so as to realize the adjustment of the distance between the trays, reduce the risk of flooding, and timely monitor and adjust the process parameters when liquid leakage occurs on the trays. In addition, it is convenient to adjust the flow rate of the liquid on the trays according to production needs, and it is convenient to intervene and clear the blockage in time when the trays are blocked.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] On the one hand, the present invention provides a methylamine rectification device, including a tower body. A skirt support is provided at the bottom of the tower body. A manhole is opened on the side of the skirt support. A drain pipe is provided at the bottom of the tower body. A ventilation hole is provided on the side of the skirt support. A steam inlet pipe is provided at the bottom side of the side of the tower body. A liquid inlet pipe is provided on the side of the tower body. A reflux pipe and a tower top suspension column are respectively provided on both sides of the top of the side of the tower body. A steam outlet pipe is provided at the top end of the tower body. A gas-liquid separator is provided at the top side inside the tower body. A tray assembly is vertically and staggeredly arranged inside the tower body;

[0009] The tray assembly includes a tray. The tray is slidably matched with the inner wall of the tower body. A plurality of air holes are evenly opened in the middle of the tray. An overflow weir is provided on one side of the tray. A downcomer is provided through the other side of the tray. The downcomer is of an arc structure. Two adjacent trays up and down are staggeredly arranged.

[0010] On the other hand, the present invention also provides a methylamine separation and purification component, applicable to the above-mentioned methylamine rectification device, including a tray assembly, and further including an adjustment component evenly arranged on the side of the tower body from top to bottom, a detection component arranged at the bottom of the tray assembly, and an auxiliary component staggeredly arranged on both sides of the inner wall of the tower body. The auxiliary component is located above the tray assembly;

[0011] The adjustment component includes a guide rail seat evenly distributed vertically. The guide rail seat is embedded in the side of the tower body. A sealed sliding seat is slidably connected inside the guide rail seat. A screw rod is vertically rotatably connected in the middle of the guide rail seat;

[0012] The detection component includes a hollow rod and a sliding rod arranged obliquely. The hollow rod is slidably sleeved outside the middle sliding rod. The end of the hollow rod is hinged to the bottom surface of the tray through a hinge seat. One ends of the outer parts of the sliding rods are jointly hinged to a collecting cylinder. An elastic member is provided on the top surface of the sliding rod through a fixing rod;

[0013] The auxiliary component includes a cover plate staggered in the vertical direction and a telescopic part arranged horizontally. The bottom of the telescopic end of the telescopic part is provided with a support rod through a mounting seat. The support rod is fixedly connected to the top of the cover plate.

[0014] Preferably, the guide rail seat corresponds to the tray in position. The sealing sliding seat is of an arc-shaped structure. The arc surface of the sealing sliding seat is fixedly connected to the side surface of the tray, and a liquid level gauge is provided on the tray.

[0015] Preferably, the screw rod is in threaded connection with the sealing sliding seat. An adjusting motor is provided at the bottom of the guide rail seat, and the output shaft of the adjusting motor is fixedly connected to the end of the screw rod.

[0016] Preferably, the hollow rods are distributed in an annular array on the bottom surface of the tray. Grooves are correspondingly formed on the upper surfaces of the sliding rods and the hollow rods, and a spring is provided between the end of the sliding rod and the inner end surface of the hollow rod.

[0017] Preferably, an elastic block is provided at the bottom of the collection cylinder. A liquid level sensor is provided inside the collection cylinder, and a liquid discharge valve is provided on one side of the bottom of the collection cylinder.

[0018] Preferably, the cover plate is located above the downcomer. The cover plate is of an arc-shaped structure, and the internal cross-sectional dimensions of the cover plate match those of the downcomer. A cleaning part is provided on the bottom surface of the cover plate, and the fixed end of the telescopic part is provided on the inner wall of the tower body.

[0019] In addition, the present invention also provides a methylamine purification process. The purification process uses the separation and purification assembly as described above to achieve the purification of methylamine during the production process, including the following steps:

[0020] S1. After preheating the material from the extraction tower, select the feed pipe located between the rectifying section and the stripping section for feeding. The incoming liquid sequentially passes through each tray assembly in a staggered manner from top to bottom;

[0021] S2. The reboiler at the bottom of the tower body inputs steam into the tower body through the steam inlet pipe to heat the incoming liquid. By adjusting the opening degree of the steam inlet valve, accurately control the steam flow rate to control the vaporization amount of the liquid in the tower kettle;

[0022] S3. The vaporized steam carries energy and mass and passes through the pores on the tray from bottom to top into the upper tray assembly. On each tray assembly, the rising steam fully contacts the liquid overflowing from the upper tray assembly;

[0023] S4. The easily volatile component of methylamine in the steam diffuses into the liquid phase, while the hardly volatile component of water in the liquid phase diffuses into the gas phase. During multiple gas-liquid contact processes, the light components of methylamine gradually accumulate towards the top of the tower body and are discharged through the gas-liquid separator and the steam outlet pipe, and the heavy components such as water move towards the bottom of the tower body to achieve preliminary separation;

[0024] S5. When a flooding condition occurs, use the adjusting assembly to adjust the distance between each tray assembly to reduce the flooding risk. When the pores are blocked, clear the blockage of the pores through the cooperation of the adjusting assembly and the detection assembly.

[0025] S6. After the steam at the top of the tower body enters the condenser, it condenses into a liquid and flows into an external reflux tank. A part of the liquid is returned to the top of the tower body as reflux liquid through a reflux pipe and flows down along the tray assembly, continuing to perform mass transfer and heat transfer with the rising steam for further separation. Another part is taken out as a product;

[0026] S7. The methylamine product taken out from the top of the tower body is transported to a product storage tank through a pipeline, and an on-line quality analyzer is set to monitor the indicators of methylamine in real time. The mixture of monomethylamine and dimethylamine obtained at the top of the tower is sent to a separation tower for further separation, and the liquid at the bottom of the tower body is discharged through a drain pipe.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] 1. When a flooding phenomenon occurs in the tower body of the present invention, the regulating motor at the liquid inlet is started to move the tray at that place upward, reducing the opening at the top of the downcomer and restricting the amount of liquid flowing from the upper tray to the lower tray per unit time, alleviating the flooding. When the flooding is still not alleviated, the other regulating motors at the bottom are started to increase the distance between the lower trays to provide a larger gas-liquid separation space, further alleviating the flooding phenomenon.

[0029] 2. When cleaning the air holes, the present invention uses the regulating motor to reduce the distance between the trays, and then makes the trays move up and down reciprocally through the regulating motor. At the same time, the hollow rod, the sliding rod and the collecting cylinder swing up and down reciprocally. At this time, the rapid up and down movement of the trays is used to make the elastic member and the elastic block respectively collide with the bottom and the top of the trays cyclically, causing the trays to vibrate and shaking off the impurities attached in the air holes, realizing the cleaning of the air holes.

[0030] 3. When cleaning the surface of the trays, the present invention uses the drive of the telescopic part to move the cover plate horizontally to a position corresponding to the edge air holes. Secondly, the top surface of the tray is made to contact the cleaning part on the bottom surface of the cover plate through the adjusting component, and the telescopic part is used to make the cover plate and the cleaning part move horizontally reciprocally, realizing the cleaning of the surface of the trays. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic structural diagram of the present invention;

[0032] Figure 2 is a schematic sectional structural diagram of the present invention;

[0033] Figure 3 is the present invention Figure 2 the enlarged structural diagram at A in;

[0034] Figure 4 is a schematic structural diagram of the separation and purification assembly of the present invention;

[0035] Figure 5This is a schematic structural diagram of another angle of the separation and purification component of the present invention.

[0036] In the figure: 1. Tower body; 101. Skirt support; 102. Manhole; 103. Drain pipe; 104. Vent hole; 105. Steam inlet pipe; 106. Feed pipe; 107. Return pipe; 108. Steam outlet pipe; 109. Top lifting column; 110. Gas-liquid separator; 2. Tray assembly; 201. Tray; 202. Air hole; 203. Overflow weir; 204. Downcomer; 3. Adjustment assembly; 301. Guide rail seat; 302. Screw; 303. Sealed sliding seat; 304. Adjustment motor; 4. Detection assembly; 401. Hinge seat; 402. Hollow rod; 403. Slide bar; 404. Spring; 405. Collection cylinder; 406. Elastic block; 407. Fixed rod; 408. Elastic member; 5. Auxiliary assembly; 501. Cover plate; 502. Telescopic part; 503. Mounting seat; 504. Support rod. Detailed implementation manners

[0037] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0038] Embodiment 1

[0039] Please refer to Figures 1-5 , this embodiment discloses a methylamine rectification device, including a tower body 1. A skirt support 101 is provided at the bottom of the tower body 1. A manhole 102 is opened on the side of the skirt support 101. A drain pipe 103 is provided at the bottom of the tower body 1. A vent hole 104 is provided on the side of the skirt support 101. A steam inlet pipe 105 is provided at the bottom side of the tower body 1. A feed pipe 106 is provided on the side of the tower body 1. A return pipe 107 and a top lifting column 109 of the tower body 1 are respectively provided on both sides of the top side of the tower body 1. A steam outlet pipe 108 is provided at the top end of the tower body 1. A gas-liquid separator 110 is provided on the top side inside the tower body 1. A tray assembly 2 is vertically and staggeredly provided inside the tower body 1.

[0040] The tray assembly 2 includes a tray 201. The tray 201 is slidably matched with the inner wall of the tower body 1. A plurality of air holes 202 are evenly opened in the middle of the tray 201. An overflow weir 203 is provided on one side of the tray 201. A downcomer 204 penetrates through the other side of the tray 201. The downcomer 204 is of an arc structure. The two adjacent trays 201 are staggeredly arranged.

[0041] During use, the material from the extraction column is transported to the feeding system of column 1. A flow meter and a regulating valve are installed on the transport pipeline to precisely control the feeding flow rate and ensure stable feeding to the rectification column. Before the material enters column 1, it is preheated using a preheater, which is preferably a shell-and-tube heat exchanger, to bring the material close to the temperature at the liquid inlet of column 1, so as to ensure that the raw material quickly reaches the gas-liquid equilibrium state after entering the column, and at the same time avoid premature vaporization of part of the methylamine due to excessive temperature, which affects the rectification effect.

[0042] Secondly, select the liquid inlet pipe 106 located between the rectifying section and the stripping section as the liquid inlet, and introduce the material into the interior of column 1. The material first falls on the topmost tray 201 and flows horizontally to the other side's downcomer 204, then passes through the downcomer 204 and falls on the next lower tray 201 and then flows horizontally towards the downcomer 204. In this way, the material flows staggered from top to bottom on each tray 201. At the same time, the bottom reboiler injects steam into the bottom of column 1 through the steam inlet pipe 105. By adjusting the opening degree of the steam inlet valve, the steam flow rate is precisely controlled. The introduced steam passes through each tray 201 in sequence from bottom to top through the air holes 202. When the liquid material flows horizontally on the tray 201, it contacts the rising steam. Part of the liquid material vaporizes to generate rising steam. The vaporized steam passes through the air holes 202 from bottom to top and enters the upper tray. On each tray 201, the rising steam fully contacts the liquid from the upper tray 201. According to the gas-liquid equilibrium principle, the volatile components such as methylamine in the steam will diffuse into the liquid phase because their concentration in the gas phase is higher than that in the liquid phase; while the less volatile components such as water in the liquid phase will diffuse into the gas phase. In the process of multiple gas-liquid contacts, the light components such as methylamine gradually accumulate towards the top of the column, and the heavy components such as water move towards the bottom of the column to achieve preliminary separation.

[0043] The steam at the top of the column enters the external condenser and condenses into a liquid. The condensed liquid flows into the external reflux tank. The flow rate of the reflux pump is adjusted by the reflux ratio controller. Part of the liquid is returned to the top of column 1 as reflux liquid, and the other part is taken out as the top product. As the gas-liquid mass transfer process proceeds, water, as a heavy component, continuously flows towards the bottom of column 1 under the action of gravity. At the bottom of the column, water gradually accumulates and its concentration continuously increases. By controlling the bottom temperature and the tray efficiency, water is effectively separated at the bottom of the column.

[0044] When the methylamine product taken out from the top of the column is transported to the product through the pipeline, on-line quality analyzers are used to monitor in real time indicators such as the purity and water content of methylamine. The liquid at the bottom of the column is discharged through the drain pipe 103.

[0045] Example 2

[0046] This embodiment discloses a methylamine separation and purification component, which includes a tray component 2. The separation and purification component further includes an adjustment component 3 uniformly arranged on the side of the tower body 1 from top to bottom and an auxiliary component 5 staggered on both sides of the inner wall of the tower body 1. The auxiliary component 5 is located above the tray component 2.

[0047] The adjustment component 3 includes guide rail seats 301 vertically and uniformly distributed. The guide rail seats 301 correspond to the positions of the trays 201. The guide rail seats 301 are embedded in the side of the tower body 1. A sealing sliding seat 303 is slidably connected in the guide rail seats 301. The sealing sliding seat 303 is of an arc structure. The arc surface of the sealing sliding seat 303 is fixedly connected to the side surface of the tray 201. The inner arc surface of the sealing sliding seat 303 is co-circular with the side surface of the guide rail seat 301 and the inner wall of the tower body 1 to ensure the sealing effect and prevent air leakage and liquid leakage. A screw rod 302 is vertically rotatably connected to the middle of the guide rail seat 301. The screw rod 302 is threadedly connected to the sealing sliding seat 303. An adjustment motor 304 is arranged at the bottom of the guide rail seat 301. The output shaft of the adjustment motor 304 is fixedly connected to the end of the screw rod 302. Specifically, by driving the screw rod 302 to rotate forward and backward by the adjustment motor 304, the tray 201 can be driven to move up and down through the sealing sliding seat 303 to adjust the distance between each tray 201.

[0048] A liquid level gauge is arranged on the tray 201. The liquid level gauge is used to detect the liquid level on the tray 201 to judge whether the phenomenon of liquid flooding occurs.

[0049] The auxiliary component 5 includes cover plates 501 staggered in the vertical direction and a telescopic part 502 arranged horizontally. The cover plates 501 are located above the downcomers 204. The fixed end of the telescopic part 502 is arranged on the inner wall of the tower body 1. The telescopic part 502 is an electric telescopic mechanism or a hydraulic telescopic mechanism. A support rod 504 is arranged at the bottom of the telescopic end of the telescopic part 502 through a mounting seat 503. The support rod 504 is fixedly connected to the top of the cover plate 501. By driving the tray 201 to move upward by using the adjustment component 3, the distance between the top end of the downcomer 204 and the cover plate 501 is adjusted, and then the opening size of the downcomer 204 is adjusted.

[0050] It should be noted that when adjusting the opening size of the top of the downcomer 204, in order to prevent the distance between each tray 201 from changing, each adjustment component 3 should drive each tray 201 to move synchronously.

[0051] During use, when the liquid level meter detects that the liquid level on the corresponding tower tray 201 is greater than the liquid level threshold set by the liquid level meter, it means that liquid has accumulated on the lower tower tray 201, and it is actively judged that liquid flooding has occurred. At this time, the regulating motor 304 close to the liquid inlet is started first, and the tower tray 201 at the liquid inlet moves upward through the cooperation of the screw 302 and the sealing slide 303, so that the top of the downcomer 204 is close to the cover plate 501, thereby reducing the top opening of the downcomer 204 at the liquid inlet, limiting the amount of liquid flowing from the upper tower tray 201 to the lower tower tray 201 per unit time, reducing the thickness of the liquid layer on the lower tower tray 201, slowing down the flow rate of the liquid on the lower tower tray 201, and prolonging the residence time of the liquid on the tower tray 201, so as to make the gas-liquid contact more orderly and alleviate liquid flooding.

[0052] When the liquid level meter detects that the flooding phenomenon has not been alleviated, the remaining regulating motors 304 at the bottom are synchronously started to increase the distance between the lower tower plates 201 and the spacing between the tower plates 201, thereby providing a larger gas-liquid separation space and further alleviating the flooding phenomenon.

[0053] However, during the separation and purification process, when the gas-liquid flow rate in the tower is lower than the lower limit of the carrying capacity of the tray assembly 2, the liquid on the tray 201 does not fully contact the gas phase and directly flows down from the tray holes, resulting in liquid leakage, which cannot be monitored in time and reduces the dehydration effect. In order to solve the above problems, the following improvements are made:

[0054] The separation and purification component also includes a detection component 4 arranged at the bottom of the tower plate component 2, and the detection component 4 includes an inclined hollow rod 402 and a sliding rod 403. The hollow rod 402 is distributed in a circular array on the bottom surface of the tower plate 201, and the hollow rod 402 is slidably sleeved on the outside of the sliding rod 403. The end of the hollow rod 402 is hinged to the bottom surface of the tower plate 201 through a hinge seat 401. The upper surfaces of the sliding rod 403 and the hollow rod 402 are respectively provided with grooves, and the grooves are used to guide the flow direction of the liquid. A spring 404 is provided between the end of the sliding rod 403 and the internal end surface of the hollow rod 402. A collecting tube 405 is hinged to the outer end of each sliding rod 403. A liquid level sensor is provided inside the collecting tube 405. A drain valve is provided on one side of the bottom of the collecting tube 405, and the drain valve is used to discharge the liquid in the collecting tube 405.

[0055] During use, when liquid leakage occurs on the tower plate 201, the leaked liquid will fall into the grooves on the upper side of the sliding rod 403 and the hollow rod 402, and flow along the grooves to the collecting tube 405. When the liquid level sensor inside the collecting tube 405 detects that liquid has entered and the liquid level has risen rapidly, it is actively determined that there is leakage on the tower plate 201, and at the same time, an abnormal signal is sent to the external control terminal to remind the staff to adjust the process parameters.

[0056] It should be noted that, in order to improve the accuracy and timeliness of detection, by increasing the density of the annular array of the sliding rod 403 and the hollow rod 402, the liquid leaking from the tray 201 is more likely to fall into the grooves on the sliding rod 403 and the hollow rod 402, thereby making the detection more timely and accurate.

[0057] In addition, after long-term use, the air holes 202 on the tray 201 will be blocked by impurities in the material, reducing the mass transfer and heat transfer efficiency. To solve the above problems, the following improvements are made:

[0058] The top surface of the sliding rod 403 is provided with an elastic member 408 through a fixing rod 407, and the bottom of the collection cylinder 405 is provided with an elastic block 406. The elastic member 408 and the elastic block 406 are preferably made of rubber, and the collection cylinder 405 has a certain weight.

[0059] In order to prevent the air holes 202 from being blocked after long-term use, a cleaning process is performed on the tray 201 after each use to clean the air holes 202. During the cleaning, the adjustment motor 304 is started to make the trays 201 approach each other, reducing the distance between the trays 201. Then, the adjustment motors 304 rotate forward and backward, and the forward and backward rotation of the screw 302 drives the sealing sliding seat 303 and each tray 201 to move up and down rapidly in a reciprocating manner. At the same time, the hollow rods 402 and the sliding rods 403 swing up and down rapidly. When the tray 201 moves upward rapidly, under the action of the self-weight of the collection cylinder 405, the tray 201 and the collection cylinder 405 will first move away from each other, and the spring 404 is stretched. When the tray 201 moves downward rapidly, under the elastic action of the spring 404, the tray 201 and the collection cylinder 405 move closer to each other, causing the elastic member 408 to hit the bottom of the tray 201, thereby causing the tray 201 to vibrate. At the same time, during this process, under the action of the elasticity of the elastic member 408 itself, the elastic member 408 will quickly rebound downward after hitting the bottom of the tray 201, and the collection cylinder 405 moves downward rapidly, causing the elastic block 406 at the bottom of the collection cylinder 405 to hit the top of the lower tray 201, realizing the intermittent impact on the top of the tray 201. Thus, by the rapid up and down movement of the tray 201, the intermittent impacts of the elastic member 408 and the elastic block 406 on the bottom and top of the tray 201 are realized, causing the tray 201 to vibrate and shaking off the impurities attached in the air holes 202. Therefore, the present invention realizes the cleaning of the air holes 202 through the coordinated cooperation between the adjustment assembly 3 and the detection assembly 4, preventing the tray 201 from being blocked during use.

[0060] In addition, after long-term use, more impurities will adhere to the surface of the tray 201 and the inner wall of the downcomer 204, accelerating the corrosion of the surfaces of the tray 201 and the downcomer 204. Therefore, the following improvements are made:

[0061] The bottom surface of the cover plate 501 is provided with a cleaning part, and the cleaning part is preferably a soft brush.

[0062] The cover plate 501 is of an arc-shaped structure, and the internal cross-sectional dimensions of the cover plate 501 match those of the downcomer 204.

[0063] After cleaning the air holes 202 by the above method, the surface of the tray 201 is cleaned. When cleaning, the telescopic part 502 is extended to drive the cover plate 501 to move horizontally, so that the cover plate 501 corresponds to the position of the air holes 202 at the edge. Then, the adjusting component 3 is used to move the tray 201 upward until the tray 201 abuts against the cleaning part on the bottom surface of the cover plate 501. Then, the telescopic part 502 moves horizontally to drive the cover plate 501 and the cleaning part at the bottom to move horizontally back and forth, so as to clean the surface of the tray 201. Moreover, the length of the cleaning part is sufficient to cover the width of the air holes 202. At the same time, clean water or a special cleaning liquid is introduced into the tower body 1 from the liquid inlet pipe 106 and flows through each tray 201 from top to bottom in sequence, so that the impurities cleaned from the tray 201 can be washed to the bottom of the tower body 1 and discharged from the drain pipe 103, thus completing the cleaning of the surface of the tray 201. Therefore, the present invention realizes the cleaning of the surface of the tray 201 through the linkage cooperation between the adjusting component 3 and the auxiliary component 5, and delays the corrosion of the surface of the tray 201.

[0064] When cleaning the inner wall of the downcomer 204, each adjusting motor 304 is synchronously started to drive the downcomer 204 to move upward by each tray 201, so that the cover plate 501 extends into the downcomer 204, and the side surface of the cover plate 501 can be used to scrape and clean the impurities attached to the inner wall of the downcomer 204.

[0065] Embodiment III

[0066] This embodiment discloses a methylamine purification process, which includes the following steps:

[0067] S1. After preheating the material from the extraction tower, select the liquid inlet pipe 106 located between the rectifying section and the stripping section for feeding, and the entering liquid sequentially passes through each tray assembly 2 from top to bottom in a staggered manner;

[0068] S2. The reboiler at the bottom of the tower body 1 inputs steam into the tower body 1 through the steam inlet pipe 105 to heat the entering liquid, and the steam flow rate is precisely controlled by adjusting the opening degree of the steam inlet valve to control the vaporization amount of the liquid in the tower kettle;

[0069] S3. The vaporized steam carries energy and mass and passes upward through the air holes 202 on the tray 201 into the upper tray assembly 2. On each tray assembly 2, the rising steam fully contacts the liquid overflowing from the upper tray assembly 2;

[0070] S4. The volatile components of methylamine in the steam diffuse into the liquid phase, while the non-volatile components of water in the liquid phase diffuse into the gas phase. During multiple gas-liquid contact processes, the light components of methylamine gradually accumulate at the top of the tower body 1 and are discharged through the gas-liquid separator 110 and the steam outlet pipe 108. The heavy components such as water move towards the bottom of the tower body 1 to achieve preliminary separation;

[0071] S5. When a flooding condition occurs, the distance between each tray assembly 2 is adjusted by the adjustment assembly 3 to reduce the flooding risk. When the air hole 202 is blocked, the air hole 202 is cleared by the cooperation of the adjustment assembly 3 and the detection assembly 4;

[0072] S6. The steam at the top of the tower body 1 enters the condenser and condenses into a liquid, which then flows into an external reflux tank. A part of the liquid returns to the top of the tower body 1 as reflux liquid through the reflux pipe 107 and flows down along the tray assembly 2 to continue mass transfer and heat transfer with the rising steam for further separation. Another part is taken out as a product;

[0073] S7. The methylamine product taken out from the top of the tower body 1 is transported to the product storage tank through a pipeline, and an on-line quality analyzer is set to monitor the indicators of methylamine in real time. The mixture of monomethylamine and dimethylamine obtained at the top of the tower is sent to a separation tower for further separation. The liquid at the bottom of the tower body 1 is discharged through the drain pipe 103.

[0074] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. A methylamine distillation device, comprising a tower body (1) and a separation and purification component, characterized in that: The separation and purification assembly comprises a tower plate assembly (2) vertically staggeredly arranged inside the tower body (1); The tower plate assembly (2) comprises a tower plate (201), the tower plate (201) is slidably matched with the inner wall of the tower body (1), the middle of the tower plate (201) is evenly provided with air holes (202), one side of the tower plate (201) is provided with an overflow weir (203), and the other side of the tower plate (201) is penetrated by a downcomer (204), the downcomer (204) is an arc-shaped structure, and two tower plates (201) adjacent to each other are arranged in a staggered manner; The separation and purification assembly further comprises an adjustment assembly (3) evenly arranged on the side of the tower body (1) from top to bottom, a detection assembly (4) arranged at the bottom of the tower plate assembly (2), and auxiliary assemblies (5) staggeredly arranged on both sides of the inner wall of the tower body (1), wherein the auxiliary assemblies (5) are located on the upper side of the tower plate assembly (2); The adjustment assembly (3) comprises a vertically evenly distributed guide rail seat (301), the guide rail seat (301) being embedded in the side of the tower body (1), a sealing sliding seat (303) being slidably connected inside the guide rail seat (301), and a screw rod (302) being vertically rotatably connected in the middle of the guide rail seat (301); The detection assembly (4) comprises a hollow rod (402) and a sliding rod (403) which are arranged obliquely, the hollow rod (402) being slidably sleeved on the outside of the sliding rod (403), the end of the hollow rod (402) being hinged to the bottom surface of the tower plate (201) via a hinge seat (401), the outer end of each sliding rod (403) being hinged to a collecting cylinder (405), and the top surface of the sliding rod (403) being provided with an elastic member (408) via a fixing rod (407); The auxiliary component (5) comprises cover plates (501) staggeredly distributed in the vertical direction and a telescopic portion (502) arranged horizontally, a support rod (504) being provided at the bottom of the telescopic end of the telescopic portion (502) via a mounting seat (503), and the support rod (504) being fixedly connected to the top of the cover plate (501); The guide rail seat (301) corresponds to the position of the tower plate (201); the sealing slide seat (303) is an arc-shaped structure; the arc-shaped surface of the sealing slide seat (303) is fixedly connected to the side surface of the tower plate (201); and a liquid level meter is provided on the tower plate (201); The hollow rods (402) are distributed in a circular array on the bottom surface of the tower plate (201), the upper surfaces of the sliding rods (403) and the hollow rods (402) are respectively provided with grooves, and a spring (404) is provided between the end of the sliding rod (403) and the inner end surface of the hollow rod (402); An elastic block (406) is provided at the bottom of the collecting cylinder (405), a liquid level sensor is provided inside the collecting cylinder (405), and a liquid drain valve is provided at one side of the bottom of the collecting cylinder (405); The cover plate (501) is located above the downcomer (204); the cover plate (501) is an arc-shaped structure; the cover plate (501) matches the internal cross-sectional dimensions of the downcomer (204); a cleaning portion is provided on the bottom surface of the cover plate (501); and a fixed end of the telescopic portion (502) is provided on the inner wall of the tower body (1).

2. The methylamine distillation equipment according to claim 1, characterized in that: The bottom of the tower body (1) is provided with a skirt seat (101), a manhole (102) is provided on the side of the skirt seat (101), a liquid discharge pipe (103) is provided at the bottom of the tower body (1), a ventilation hole (104) is provided on the side of the skirt seat (101), a steam introduction pipe (105) is provided at the bottom of the side of the tower body (1), a liquid inlet pipe (106) is provided on the side of the tower body (1), a return pipe (107) and a tower body (1) top suspension column (109) are respectively provided on both sides of the top of the side of the tower body (1), a steam outlet pipe (108) is provided at the top of the tower body (1), and a gas-liquid separator (110) is provided on the inner top side of the tower body (1).

3. The methylamine distillation equipment according to claim 1, characterized in that: The screw rod (302) is threadedly connected to the sealing sliding seat (303); an adjusting motor (304) is provided at the bottom of the guide rail seat (301); and an output shaft of the adjusting motor (304) is fixedly connected to the end of the screw rod (302).

4. A methylamine purification process, wherein the methylamine distillation equipment according to claim 1 is used to purify methylamine in the production process, characterized in that: The following steps are involved: S1, after preheating the material from the extraction tower, select the liquid inlet pipe (106) located between the distillation section and the stripping section to feed the material, and the incoming liquid passes through each tray assembly (2) in an alternating manner from top to bottom; S2, the reboiler at the bottom of the tower body (1) inputs steam into the tower body (1) through the steam inlet pipe (105) to heat the incoming liquid, and the steam flow rate is accurately controlled by adjusting the opening of the steam inlet valve to control the vaporization amount of the liquid in the tower bottom; S3, the vaporized steam carries energy and mass from bottom to top through the air holes (202) on the tray (201) and enters the upper tray assembly (2). On each tray assembly (2), the rising steam fully contacts the liquid overflowing from the upper tray assembly (2); S4, the volatile component of methylamine in the steam diffuses into the liquid phase, while the non-volatile component of water in the liquid phase diffuses into the gas phase. During multiple gas-liquid contact processes, the light component of methylamine gradually accumulates at the top of the tower body (1) and is discharged through the gas-liquid separator (110) and the steam outlet pipe (108), while the heavy component of water moves to the bottom of the tower body (1), thereby achieving preliminary separation; S5. When a flooding condition occurs, the distance between each tower plate assembly (2) is adjusted by using the adjustment assembly (3) to reduce the risk of flooding. When the air hole (202) is blocked, the air hole (202) is cleared by cooperating with the adjustment assembly (3) and the detection assembly (4); S6, the steam at the top of the tower body (1) enters the condenser and condenses into liquid and flows into the external reflux tank. A portion of the liquid is returned to the top of the tower body (1) through the reflux pipe (107) as reflux liquid and flows down along the tower plate assembly (2), continuing to transfer mass and heat with the rising steam for further separation, and the other portion is extracted as a product; S7. The methylamine product extracted from the top of the tower body (1) is transported to a product storage tank through a pipeline and an online mass analyzer is set to monitor the methylamine index in real time. The mixture of monomethylamine and dimethylamine extracted from the top of the tower is sent to a separation tower for further separation. The liquid at the bottom of the tower body (1) is discharged through a drain pipe (103).

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