A 2-chloronicotinic acid production, separation and purification process

Abstract

The invention belongs to the technical field of 2-chloronicotinic acid production, and specifically is a 2-chloronicotinic acid production separation and purification process, comprising the following steps: S1: inputting a 2-chloronicotinic acid raw material solution into a tank body of a separation device from a feed inlet, and at the same time, starting a motor to drive an absorption column to start moving; the running speed of the motor is periodically changed within a set speed range; S2: starting an external suction pump to extract liquid in the absorption column through a liquid outlet pipe and a floating block; the suction pump is temporarily closed periodically; S3: after the liquid in the tank body is completely extracted and solid-liquid separation is completed, the 2-chloronicotinic acid crystals in the tank body are taken out through a discharge port; the invention isolates the crystals in the raw material solution through a rotating absorption column and separates the crystals attached to the absorption column through centrifugal force and friction of the liquid, thereby avoiding the crystals from being extracted through a filter screen to cause waste and avoiding the crystals from clogging the filter screen, thereby affecting the efficiency of solid-liquid separation.

Description

Technical Field

[0001] The invention belongs to the technical field of 2-chloronicotinic acid production, in particular to a 2-chloronicotinic acid production, separation and purification process. Background Art

[0002] 2-Chloronicotinic acid is a commonly used intermediate in the chemical field. It can not only be used as a pharmaceutical intermediate for the manufacture of non-steroidal anti-inflammatory drugs, such as niflumic acid, pranoprofen, nicotinic acid and nicotinic acid; it can also be used as a pesticide intermediate and is an important intermediate for the manufacture of herbicides nicosulfuron and diflufenicol. These products are in large supply, so research on the preparation of 2-chloronicotinic acid is of great significance.

[0003] 2-Chloronicotinic acid is a chemical substance, usually in the form of white powder. When the existing 2-chloronicotinic acid separation and purification device performs solid-liquid separation, since 2-chloronicotinic acid is in powder form, it is easy to bring out the powder body together, which easily leads to reduced yield and waste of raw materials. At the same time, during separation, the powdered 2-chloronicotinic acid particles are also easy to penetrate into the mesh of the filter, causing the filter to be blocked, affecting the normal operation of the purification device, and reducing the solid-liquid separation efficiency. Summary of the invention

[0004] In order to make up for the shortcomings of the prior art, the present invention proposes a production, separation and purification process for 2-chloronicotinic acid, by isolating the crystals in the raw material solution through a rotating absorption column and detaching the crystals already attached to the absorption column through centrifugal force and the friction of the liquid, thereby avoiding the crystals from passing through the filter screen and being sucked away to cause waste and avoiding the crystals from clogging the filter screen and affecting the efficiency of solid-liquid separation.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a 2-chloronicotinic acid production, separation and purification process according to the present invention comprises the following steps:

[0006] S1: The 2-chloronicotinic acid raw material solution is fed into the tank of the separation device from the feed port, and at the same time, the motor is started to drive the absorption column to start moving; the running speed of the motor is periodically changed within a set speed range;

[0007] S2: Start the external suction pump to extract the liquid in the absorption column through the liquid outlet pipe and the floating block; the suction pump will be temporarily closed periodically;

[0008] S3: After the liquid in the tank body is completely extracted and the solid-liquid separation is completed, the 2-chloronicotinic acid crystals in the tank body are taken out through the discharge port;

[0009] Wherein, the separation device in step S1 comprises a tank body, a top cover is installed on the tank body, and a feed inlet and a discharge port are installed on the tank body;

[0010] An absorption column is installed in the tank body, and the absorption column includes a frame and a filter screen, and the filter screen is evenly installed on the frame. A motor is installed under the tank body, and the motor drives the absorption column to rotate;

[0011] A floating block is slidably installed in the absorption column, and a retractable liquid outlet pipe is installed on the floating block. The liquid outlet pipe extends from the top cover and is connected to an external suction pump;

[0012] A plurality of separation discs are installed on the surface of the absorption column, and arc-shaped convex plates are arranged on the surface of the separation discs.

[0013] Preferably, a mounting shaft is mounted on the top cover, a curved baffle is mounted on the lower end of the mounting shaft, the curved baffle is in contact with the inner wall of the absorption column, a sliding groove is provided on the floating block, and the curved baffle is located in the sliding groove;

[0014] The installation shaft is a hollow shaft, and the liquid outlet pipe passes through the installation shaft.

[0015] Preferably, a sponge strip is installed at the edge of the arc-shaped baffle plate, and the sponge strip is used to block the gap between the arc-shaped baffle plate and the inner wall of the absorption column.

[0016] Preferably, a through hole is opened in the middle of the separation disk, the diameter of the through hole is larger than the diameter of the absorption column, and a connecting rod is installed on the separation disk, and the other end of the connecting rod is installed on the frame of the absorption column.

[0017] Preferably, the diameter of the separation disc increases gradually from top to bottom, and the diameters of the through holes on each separation disc are the same.

[0018] Preferably, the frame is provided with movable grooves, which are symmetrically distributed at the upper and lower ends of the frame, and movable rods are slidably installed in the movable grooves, and the movable rods are in contact with the surface of the filter screen.

[0019] Preferably, elastic rods are installed between adjacent movable rods, and the movable rods are evenly distributed in the movable grooves under the action of the elastic rods.

[0020] Preferably, a silicone layer is provided on the surface of the movable rod, and evenly distributed grooves are formed on the surface of the silicone layer.

[0021] The beneficial effects of the present invention are as follows:

[0022] 1. The present invention discloses a 2-chloronicotinic acid production separation and purification process, which isolates crystals in a raw material solution through an absorption column to prevent the crystals from passing through a liquid and being sucked away together, thereby reducing the yield and wasting raw materials. At the same time, through the rotation of the absorption column, the crystals attached to the surface of the absorption column are affected by centrifugal force and the friction of the liquid, thereby promoting the crystals to separate from the filter screen. At the same time, the separation disk on the absorption column further drives the liquid to flow, thereby promoting the crystals to move away from the absorption column, thereby preventing the crystals from clogging the filter screen and affecting the efficiency of solid-liquid separation.

[0023] 2. The present invention discloses a 2-chloronicotinic acid production, separation and purification process. By arranging an absorption column, a floating block and a separation plate, the absorption column and the separation plate are rotated, thereby driving the liquid to perform centrifugal motion, and promoting the crystals in the liquid to move away from the absorption column, thereby preventing the crystals from passing through the filter and being sucked away together, resulting in reduced yield and waste of raw materials. At the same time, the crystals attached to the surface of the absorption column will detach from the filter under the action of centrifugal force and the friction of the liquid, and then be driven away from the absorption column by the liquid, thereby preventing the crystals from clogging the filter and affecting the efficiency of solid-liquid separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below in conjunction with the accompanying drawings.

[0025] Figure 1 It is a flowchart of the steps of the process of the present invention;

[0026] Figure 2 is a front view of a separation device used in the process of the present invention;

[0027] Figure 3 is a schematic diagram of the structure of a separation device used in the process of the present invention;

[0028] Figure 4 is a schematic diagram of the structure of an absorption column in a separation device used in the process of the present invention;

[0029] Figure 5 is a schematic diagram of the structure of a floating block in a separation device used in the process of the present invention;

[0030] Figure 6 is a schematic diagram of the structure of a movable rod in a separation device used in the process of the present invention;

[0031] Figure 7 is a schematic diagram of the structure of a separation disk in a separation device used in the process of the present invention;

[0032] Figure 8 yes Figure 4 A partial enlarged view of the middle part;

[0033] Fig. 9 yes Figure 4 A partial enlarged view of point B in the middle;

[0034] Fig.10 yes Figure 4 A partial enlarged view of point C in the middle;

[0035] In the figure: tank body 1, top cover 11, feed port 12, discharge port 13, motor 14, mounting shaft 2, arc baffle 21, sponge bar 211, liquid outlet pipe 22, floating block 23, slide 231, absorption column 3, frame 31, movable groove 311, filter screen 32, separation plate 4, connecting rod 41, raised plate 42, movable rod 5, elastic rod 51. DETAILED DESCRIPTION

[0036] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0037] like Figures 1 to 10 As shown, the present invention provides a 2-chloronicotinic acid production, separation and purification process, the process comprising the following steps:

[0038] S1: The 2-chloronicotinic acid raw material solution is fed into the tank 1 of the separation device from the feed port 12, and at the same time, the motor 14 is started to drive the absorption column 3 to start moving; the running speed of the motor 14 is periodically changed within a set speed range;

[0039] S2: Start the external suction pump to extract the liquid in the absorption column 3 through the liquid outlet pipe 22 and the floating block 23; the suction pump will be temporarily closed periodically;

[0040] S3: After the liquid in the tank body 1 is completely extracted and the solid-liquid separation is completed, the 2-chloronicotinic acid crystals in the tank body 1 are taken out through the discharge port 13;

[0041] When 2-chloronicotinic acid is separated and purified, after the raw material solution is added to the separation device, the motor 14 and the suction are started, thereby driving the absorption column 3 to start rotating, and liquid is extracted from the absorption column 3. At this time, the rotation of the absorption column 3 drives the liquid near the surface of the absorption column 3 to rotate, generating centrifugal force, and the 2-chloronicotinic acid crystals in the raw material solution are thrown off, reducing the possibility of the crystals contacting and adsorbing on the absorption column 3. At the same time, the rotation of the absorption column 3 increases the friction between the surface of the absorption column 3 and the liquid, and promotes the crystals adsorbed on the surface of the absorption column 3 to be washed away, thereby effectively avoiding the 2-chloronicotinic acid crystals being adsorbed on the absorption column 3, resulting in clogging of the filter screen 32, and affecting the efficiency and separation effect of solid-liquid separation;

[0042] At the same time, since the rotation speed of the motor 14 will change and the suction pump will be temporarily closed periodically, the rotation speed of the absorption column 3 will change through the change of the rotation speed of the motor 14, thereby changing the centrifugal force of the liquid near the surface of the absorption column 3 and the inertial force of the crystals adsorbed on the absorption column 3, thereby promoting the separation of the crystals near the surface of the absorption column 3 or adsorbed on the absorption column 3, avoiding the clogging of the filter screen 32 on the absorption column 3 or the 2-chloronicotinic acid crystals being sucked away with the liquid at the absorption column 3, causing the loss of 2-chloronicotinic acid crystals. At the same time, when the suction pump is temporarily closed, the absorption column 3 does not have a negative pressure attraction for the liquid. The centrifugal force and inertial force changes caused by the change of the rotation speed of the absorption column 3 can further promote the crystals near the surface of the absorption column 3 and adsorbed on the absorption column 3 to move away from and separate from the absorption column 3, avoiding the clogging of the filter screen 32 on the absorption column 3, which affects the effect and efficiency of solid-liquid separation.

[0043] Wherein, the separation device in step S1 comprises a tank body 1, a top cover 11 is installed on the tank body 1, and a feed port 12 and a discharge port 13 are installed on the tank body 1;

[0044] An absorption column 3 is installed in the tank body 1, and the absorption column 3 includes a frame 31 and a filter 32. The filter 32 is evenly installed on the frame 31. A motor 14 is installed below the tank body 1, and the motor 14 drives the absorption column 3 to rotate;

[0045] A floating block 23 is slidably mounted in the absorption column 3, and a retractable liquid outlet pipe 22 is mounted on the floating block 23. The liquid outlet pipe 22 extends from the top cover 11 and is connected to an external suction pump.

[0046] A plurality of separation discs 4 are installed on the surface of the absorption column 3, and arc-shaped raised plates 42 are arranged on the surface of the separation discs 4;

[0047] When 2-chloronicotinic acid is separated and purified, the motor 14 drives the absorption column 3 to rotate, so that the 2-chloronicotinic acid crystals near the surface of the absorption column 3 and on the surface of the absorption column 3 are away from and separated from the absorption column 3, so as to avoid the crystals passing through the filter screen 32 and being drawn away, causing waste or the crystals clogging the filter screen 32, thereby affecting the effect and efficiency of solid-liquid separation;

[0048] At the same time, since the floating block 23 is installed in the absorption column 3, the floating block 23 will change with the change of the liquid level in the tank body 1, ensuring that the liquid in the tank body 1 is always sucked and the solid-liquid separation is smoothly carried out. At the same time, since the floating block 23 is connected to the top cover 11 through the liquid outlet pipe 22, when the absorption column 3 rotates, the floating block 23 will not rotate;

[0049] At the same time, when the absorption column 3 drives the separation disk 4 to rotate, the separation disk 4 and the arc-shaped raised plate 42 will also drive the liquid, thereby increasing the centrifugal force on the liquid, promoting the liquid and the crystals in the liquid to be thrown toward the inner wall of the tank body 1, and further promoting the crystals near the surface of the absorption column 3 and adsorbed on the surface of the absorption column 3 to move away from and detach from the surface of the absorption column 3, thereby reducing the number of crystals contained in the liquid near the absorption column 3, thereby reducing the possibility of relatively small crystals passing through the filter screen 32 and relatively large crystals being adsorbed on the filter screen 32, improving the effect and efficiency of solid-liquid separation, and avoiding as much as possible the 2-chloronicotinic acid crystals being pumped away with the liquid to cause waste.

[0050] As an embodiment of the present invention, the top cover 11 is provided with a mounting shaft 2, the lower end of the mounting shaft 2 is provided with an arc-shaped baffle 21, the arc-shaped baffle 21 is in contact with the inner wall of the absorption column 3, the floating block 23 is provided with a slide groove 231, and the arc-shaped baffle 21 is located in the slide groove 231;

[0051] The installation shaft 2 is a hollow shaft, and the liquid outlet pipe 22 passes through the installation shaft 2;

[0052] Since there are multiple groups of arc-shaped baffles 21, through the contact between the arc-shaped baffles 21 and the inner wall of the absorption column 3, the arc-shaped baffles 21 act as the rotation axis of the absorption column 3, thereby improving the stability of the absorption column 3 during rotation and avoiding vibration and shaking of the absorption column 3 during rotation;

[0053] At the same time, since the arc-shaped baffle 21 and the inner wall of the absorption column 3 are in contact with each other, the portion where the filter screen 32 on the absorption column 3 contacts the arc-shaped baffle 21 is isolated from the space inside the absorption column 3, that is, there is no negative pressure attraction at the portion where the filter screen 32 contacts the arc-shaped baffle 21. Therefore, as the absorption column 3 rotates, the filter screen 32 on the absorption column 3 will continuously contact the arc-shaped baffle 21, and then when there is no negative pressure attraction, the crystals adsorbed on the surface of the absorption column 3 are washed away by the centrifugal force and the friction of the liquid, thereby promoting the detachment of the crystals attached to the absorption column 3, avoiding the crystals from clogging the filter screen 32 and affecting the efficiency and effect of solid-liquid separation.

[0054] As an embodiment of the present invention, a sponge strip 211 is installed at the edge of the arc-shaped baffle plate 21, and the sponge strip 211 blocks the gap between the arc-shaped baffle plate 21 and the inner wall of the absorption column 3;

[0055] Since the arc baffle 21 and the inner wall of the absorption column 3 are in contact with each other, there will be friction between the two when the absorption column 3 rotates, which can easily cause the filter screen 32 on the absorption column 3 to be worn and damaged, and the arc baffle 21 to be worn, affecting the normal use of the separation device. At the same time, by installing a sponge strip 211 on the arc baffle 21, the sponge strip 211 is used to block the gap between the arc baffle 21 and the inner wall of the absorption column 3, so that there is a tiny gap between the arc baffle 21 and the inner wall of the absorption column 3, and the friction between the two is buffered and isolated by the sponge, so as to avoid excessive wear between the absorption column 3 and the arc baffle 21 during rotation, which affects the normal use of the separation device.

[0056] At the same time, since the sponge strip 211 is elastic and contacts the inner wall of the absorption column 3, during the rotation process, the sponge strip 211 will scrape and clean the inner wall of the absorption column 3, that is, clean the filter screen 32 on the absorption column 3, thereby promoting the detachment of crystals adsorbed on the absorption column 3, avoiding clogging the filter screen 32 and affecting the effect and efficiency of solid-liquid separation.

[0057] As an embodiment of the present invention, a through hole is opened in the middle of the separation disk 4, the diameter of the through hole is larger than the diameter of the absorption column 3, and a connecting rod 41 is installed on the separation disk 4, and the other end of the connecting rod 41 is installed on the frame 31 of the absorption column 3;

[0058] When the separation disk 4 rotates with the absorption column 3, the separation disk 4 will drive the liquid to rotate, so that the liquid is thrown toward the inner wall of the tank body 1 under the action of centrifugal force. At this time, the liquid near the absorption column 3 and the separation disk 4 will flow. By opening a through hole on the separation disk 4, a gap is created between the through hole and the absorption column 3. When the multiple sets of separation disks 4 are set to drive the liquid to flow synchronously, the liquid flows vertically along the surface of the absorption column 3 to supplement the liquid taken away by the separation disk 4 in the middle position when it rotates, thereby ensuring the normal flow of the liquid. At the same time, the surface of the absorption column 3 is flushed by the liquid flowing vertically along the surface of the absorption column 3, thereby further accelerating the detachment of crystals attached to the surface of the absorption column 3, thereby preventing the crystals from clogging the filter screen 32 and affecting the effect and efficiency of solid-liquid separation.

[0059] As an embodiment of the present invention, the diameter of the separation disc 4 gradually increases from top to bottom, and the diameters of the through holes on each separation disc 4 are the same;

[0060] Since the separation disk 4 with a relatively large diameter drives relatively more liquid when rotating, when the absorption column 3 drives the separation disk 4 to rotate, the separation disk 4 located at the lower position drives more liquid, so that the liquid as a whole flows vertically downward along the surface of the absorption column 3, and the liquid flow in the tank body 1 is relatively regular, so that the flowing liquid can wash off the crystals adsorbed on the surface of the absorption column 3, and carry the crystals away from the absorption column 3, so as to avoid the filter screen 32 on the absorption column 3 from being blocked, which affects the solid-liquid separation effect and separation efficiency of the separation device.

[0061] As an embodiment of the present invention, the frame 31 is provided with movable grooves 311, which are symmetrically distributed at the upper and lower ends of the frame 31, and a movable rod 5 is slidably installed in the movable groove 311, and the movable rod 5 is in contact with the surface of the filter screen 32;

[0062] When the rotation speed of the motor 14 changes, the movable rod 5 in the movable groove 311 will move under the action of inertia, so that the movable rod 5 scrapes the surface of the filter screen 32, thereby improving the cleaning effect of the crystals attached to the surface of the filter screen 32, and preventing the filter screen 32 from being blocked by the crystals, which affects the effect and efficiency of solid-liquid separation;

[0063] At the same time, since the movable rod 5 is in contact with the surface of the filter 32, the movable rod 5 limits and constrains the filter 32, thereby preventing the filter 32 from moving under the action of centrifugal force or detaching from the absorption column 3 when the absorption column 3 rotates, thereby ensuring that the filter 32 is stably installed on the absorption column 3, thereby ensuring the normal use of the separation device.

[0064] As an embodiment of the present invention, elastic rods 51 are installed between adjacent movable rods 5, and the movable rods 5 are evenly distributed in the movable grooves 311 under the action of the elastic rods 51;

[0065] Through the action of the elastic rod 51, each movable rod 5 is evenly distributed in the movable groove 311, so as to avoid the movable rods 5 from gathering together under the action of inertia, causing the movable rods 5 in the movable groove 311 to be concentrated together, affecting the restriction and restraint effect of the movable rods 5 on the filter 32. At the same time, it can also ensure that when the inertia effect on the movable rods 5 does not change, the movable rods 5 can automatically return to their original positions, which is convenient for the movable rods 5 to move again under the action of inertia to clean the surface of the filter 32, and avoid the movable rods 5 being unable to move when the movable rods 5 are affected by inertia after they gather together.

[0066] As an embodiment of the present invention, a silicone layer is provided on the surface of the movable rod 5, and the surface of the silicone layer is provided with evenly distributed grooves;

[0067] The silicone layer and the grooves provide a relatively good cleaning effect of the movable rod 5 on the surface of the filter 32 , and avoid direct contact between the movable rod 5 and the filter 32 , so as to avoid damage and wear of the filter 32 and affect the service life of the filter 32 .

[0068] The specific workflow is as follows:

[0069] When separating and purifying 2-chloronicotinic acid, after adding the raw material solution into the separation device, the motor 14 and the suction are started, thereby driving the absorption column 3 to start rotating and start extracting liquid from the absorption column 3;

[0070] At the same time, since the rotation speed of the motor 14 will change and the suction pump will be temporarily closed periodically, the rotation speed of the absorption column 3 will change through the change of the rotation speed of the motor 14, thereby changing the centrifugal force of the liquid near the surface of the absorption column 3 and the inertial force of the crystals adsorbed on the absorption column 3, thereby promoting the separation of the crystals near the surface of the absorption column 3 or adsorbed on the absorption column 3. At the same time, when the suction pump is temporarily closed, the absorption column 3 does not have a negative pressure attraction to the liquid. The changes in the centrifugal force and inertial force caused by the change in the rotation speed of the absorption column 3 can further promote the crystals near the surface of the absorption column 3 and adsorbed on the absorption column 3 to move away from and separate from the absorption column 3.

[0071] When 2-chloronicotinic acid is separated and purified, the absorption column 3 is driven to rotate by the motor 14, so that the 2-chloronicotinic acid crystals near the surface of the absorption column 3 and on the surface of the absorption column 3 are moved away from and separated from the absorption column 3;

[0072] At the same time, since the floating block 23 is installed in the absorption column 3, the floating block 23 will change with the change of the liquid level in the tank body 1, ensuring that the liquid in the tank body 1 is always sucked;

[0073] At the same time, when the absorption column 3 drives the separation disk 4 to rotate, the separation disk 4 and the arc-shaped raised plate 42 will also drive the liquid, promoting the liquid and the crystals in the liquid to be thrown toward the inner wall of the tank body 1, and promoting the crystals near the surface of the absorption column 3 and adsorbed on the surface of the absorption column 3 to move away from and detach from the surface of the absorption column 3;

[0074] Since there are multiple groups of arc-shaped baffles 21, the arc-shaped baffles 21 act as the rotating shaft of the absorption column 3 through the contact between the arc-shaped baffles 21 and the inner wall of the absorption column 3;

[0075] At the same time, since the arc-shaped baffle 21 and the inner wall of the absorption column 3 are in contact with each other, the portion where the filter screen 32 on the absorption column 3 contacts the arc-shaped baffle 21 is isolated from the space inside the absorption column 3, that is, there is no negative pressure attraction at the portion where the filter screen 32 contacts the arc-shaped baffle 21. Therefore, as the absorption column 3 rotates, the filter screen 32 on the absorption column 3 will continuously contact the arc-shaped baffle 21, and then when there is no negative pressure attraction, the crystals adsorbed on the surface of the absorption column 3 are washed away by the centrifugal force and the friction of the liquid, thereby promoting the separation of the crystals attached to the absorption column 3.

[0076] At the same time, by installing a sponge strip 211 on the arc baffle 21, the sponge strip 211 is used to block the gap between the arc baffle 21 and the inner wall of the absorption column 3, so that there is a tiny gap between the arc baffle 21 and the inner wall of the absorption column 3, and the friction between the two is buffered and isolated by the sponge;

[0077] Through holes are provided on the separation disc 4 so that there is a gap between the through holes and the absorption column 3. When the multiple sets of separation discs 4 are synchronously driven to flow the liquid, the liquid flows vertically along the surface of the absorption column 3 to replenish the liquid taken away by the separation disc 4 in the middle position when it rotates, thereby ensuring the normal flow of the liquid. At the same time, the surface of the absorption column 3 is flushed by the liquid flowing vertically along the surface of the absorption column 3, thereby accelerating the separation of the crystals attached to the surface of the absorption column 3.

[0078] Since the separation disc 4 with a relatively large diameter drives relatively more liquid when rotating, when the absorption column 3 drives the separation disc 4 to rotate, the separation disc 4 located at the lower position drives more liquid, so that the liquid as a whole flows vertically downward along the surface of the absorption column 3, so that the liquid flow in the tank body 1 is relatively regular, so that the flowing liquid washes down the crystals adsorbed on the surface of the absorption column 3, and carries the crystals away from the absorption column 3;

[0079] When the rotation speed of the motor 14 changes, the movable rod 5 in the movable groove 311 will move under the action of inertia, so that the movable rod 5 scrapes the surface of the filter 32 to clean the crystals attached to the surface of the filter 32;

[0080] At the same time, since the movable rod 5 and the surface of the filter 32 are in contact with each other, the movable rod 5 restricts and restrains the filter 32, thereby preventing the filter 32 from moving under the action of centrifugal force or detaching from the absorption column 3 when the absorption column 3 rotates;

[0081] Through the action of the elastic rod 51, each movable rod 5 is evenly distributed in the movable groove 311, so as to prevent the movable rods 5 from gathering together under the action of inertia;

[0082] The silicone layer and the grooves provide a relatively good cleaning effect of the movable rod 5 on the surface of the filter screen 32 , and avoid direct contact between the movable rod 5 and the filter screen 32 , so as to avoid damage and wear of the filter screen 32 .

[0083] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A 2-chloronicotinic acid production, separation and purification process, characterized in that: The process comprises the following steps: S1: The 2-chloronicotinic acid raw material solution is fed into the tank (1) of the separation device from the feed port (12), and at the same time, the motor (14) is started to drive the absorption column (3) to start moving; the running speed of the motor (14) is periodically changed within a set speed range; S2: starting an external suction pump to extract the liquid in the absorption column (3) through the liquid outlet pipe (22) and the floating block (23); the suction pump will be temporarily closed periodically; S3: After the liquid in the tank body (1) is completely extracted and the solid-liquid separation is completed, the 2-chloronicotinic acid crystals in the tank body (1) are taken out through the discharge port (13); Wherein, the separation device in step S1 comprises a tank body (1), a top cover (11) is installed on the tank body (1), and a feed inlet (12) and a discharge outlet (13) are installed on the tank body (1); An absorption column (3) is installed in the tank body (1), the absorption column (3) comprises a frame (31) and a filter screen (32), the filter screen (32) is evenly installed on the frame (31), and a motor (14) is installed below the tank body (1), and the motor (14) drives the absorption column (3) to rotate; A floating block (23) is slidably mounted in the absorption column (3), a retractable liquid outlet pipe (22) is mounted on the floating block (23), and the liquid outlet pipe (22) extends from the top cover (11) and is connected to an external suction pump; A plurality of separation discs (4) are installed on the surface of the absorption column (3), and an arc-shaped raised plate (42) is provided on the surface of the separation disc (4); The top cover (11) is provided with a mounting shaft (2), the lower end of the mounting shaft (2) is provided with an arc-shaped baffle (21), the arc-shaped baffle (21) is in contact with the inner wall of the absorption column (3), the floating block (23) is provided with a slide groove (231), and the arc-shaped baffle (21) is located in the slide groove (231); The installation shaft (2) is a hollow shaft, and the liquid outlet pipe (22) passes through the installation shaft (2); A sponge strip (211) is installed at the edge of the arc-shaped baffle plate (21), and the sponge strip (211) blocks the gap between the arc-shaped baffle plate (21) and the inner wall of the absorption column (3).

2. A 2-chloronicotinic acid production, separation and purification process according to claim 1, characterized in that: A through hole is provided in the middle of the separation disc (4), the diameter of the through hole being larger than the diameter of the absorption column (3); a connecting rod (41) is installed on the separation disc (4), and the other end of the connecting rod (41) is installed on the frame (31) of the absorption column (3).

3. A 2-chloronicotinic acid production, separation and purification process according to claim 2, characterized in that: The diameter of the separation disc (4) gradually increases from top to bottom, and the diameters of the through holes on each of the separation discs (4) are the same.

4. A 2-chloronicotinic acid production, separation and purification process according to claim 1, characterized in that: The frame (31) is provided with movable grooves (311), which are symmetrically distributed at the upper and lower ends of the frame (31). A movable rod (5) is slidably installed in the movable groove (311), and the movable rod (5) is in contact with the surface of the filter screen (32).

5. A 2-chloronicotinic acid production, separation and purification process according to claim 4, characterized in that: Elastic rods (51) are installed between adjacent movable rods (5), and the movable rods (5) are evenly distributed in the movable grooves (311) under the action of the elastic rods (51).

6. A 2-chloronicotinic acid production, separation and purification process according to claim 4, characterized in that: A silicone layer is provided on the surface of the movable rod (5), and evenly distributed grooves are provided on the surface of the silicone layer.

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