A production process and system for high-concentration 2,4-D sodium salt

Abstract

The invention discloses a production process and system of high-concentration 2,4-dichlorophenoxyacetic acid sodium salt. The main reactions involved in this process are chloroacetic acid salt-forming reaction, 2,4-dichlorophenol salt-forming reaction, and condensation reaction. After the reaction, solid-liquid separation is carried out by a filter press, and the high-salt mother liquor therein is acidified by acidification, and the two phases are separated after standing after acidification. The organic matter is recovered and applied back to the condensation reactor, and the wastewater part (containing the high-salt mother liquor) enters a triple-effect evaporation system, and biochemical sewage treatment is carried out; the (2,4-dichlorophenoxyacetic acid sodium salt) crystallization filter cake of the filter press is dried and dusted by hot air and packaged into finished products. The present invention overcomes the shortcomings of the prior art, has a reasonable design, can effectively increase the concentration of 2,4-dichlorophenoxyacetic acid sodium salt, has a good weed control effect, and has a certain prevention and control effect, and has a high social use value and application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of 2,4-D sodium salt, and in particular to a production process and system of high-concentration 2,4-D sodium salt. Background Art

[0002] 2,4-D sodium salt, chemical name is 2,4-dichlorophenoxyacetic acid sodium salt, molecular formula is C8H5Cl2O3Na, mainly used as herbicide or plant growth regulator, used to preserve flowers and fruits, can stimulate pollen germination, can better complete the fertilization process to achieve flower and fruit preservation. At the same time, it can mature early. This product is a selective systemic hormone-transmitting chemical preparation, which has strong physiological activity on plants. At low concentrations (1-30ppm), it has the function of plant growth hormone, can stimulate crop growth, preserve flowers and prevent fruit drop, promote fruit expansion, produce seedless fruits, promote early maturity, can be used as a plant growth regulator, suitable for crops such as tomatoes, eggplants, peppers, zucchini, citrus and other crops. Higher concentrations inhibit growth, and higher concentrations can cause crop deformity and death, and can be used as a herbicide.

[0003] The synthesis of 2,4-dichlorophenoxyacetic acid mainly adopts the condensation method, and the production process can be specifically divided into two types: condensation first and then chlorination and chlorination first and then condensation.

[0004] Condensation followed by chlorination means that phenol is first condensed with sodium chloroacetate to obtain sodium phenoxyacetate, and then chlorinated to obtain 2,4-dichlorophenoxyacetic acid. The advantages of this method are high condensation yield, less hydrolysis of chloroacetic acid, and high chlorination selectivity. The disadvantages are large amounts of three wastes and difficulty in treatment.

[0005] Compared with post-chlorination, the product obtained by chlorination first and then condensation has high purity and good color. The disadvantage is that the selectivity of phenol chlorination is poor. While obtaining 2,4-dichlorophenol, 2,6-dichlorophenol and other by-products will be produced, and the separation of the two is difficult; more importantly, if the hydrolysis side reaction of chloroacetic acid cannot be well controlled during the condensation reaction, it will lead to increased consumption of chloroacetic acid, greatly increasing the production cost.

[0006] At present, the production process commonly used at home and abroad is chlorination followed by condensation. However, the wastewater generated by the existing production process has defects such as high COD concentration and high salinity. At the same time, the purity of the produced 2,4-D sodium salt is not high, and it is difficult to meet higher production standards.

[0007] Therefore, in view of this, the inventor, with many years of rich experience in design, development and actual production in the relevant industry, has studied and improved the existing structure and deficiencies, and provided a production process and system for high-concentration 2,4-D sodium salt, in order to achieve a more practical purpose. Summary of the invention

[0008] In order to solve the problems mentioned in the above background technology, the present invention provides a production process and system for high-concentration 2,4-D sodium salt.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] (1) Reaction principle

[0011] The raw material chloroacetic acid is subjected to a liquid alkali neutralization and salt-forming reaction to obtain sodium chloroacetate; the raw material 2,4-dichlorophenol is subjected to a liquid alkali neutralization and salt-forming reaction to obtain sodium 2,4-dichlorophenol.

[0012]

[0013] Sodium chloroacetate and sodium 2,4-dichlorophenol are reacted by condensation to obtain the product 2,4-D sodium salt.

[0014]

[0015] (2) Reaction heat effect: In this step, the neutralization and salt-forming reaction is an exothermic reaction, and the condensation reaction is an exothermic reaction.

[0016] The main reactions involved in this process are chloroacetic acid salt formation reaction, 2,4-dichlorophenol salt formation reaction, and condensation reaction. After the reaction, the solid-liquid separation is carried out through a filter press, the high-salt mother liquor is acidified with acid, and the two phases are separated after being allowed to stand. The organic matter is recovered and reused back to the condensation reactor, and the wastewater part (including the high-salt mother liquor) enters the three-effect evaporation system and is treated with biochemical sewage; the (2,4-dichlorophenoxyacetic acid sodium salt) crystallization filter cake of the filter press is dried and dusted with hot air before packaging the finished product.

[0017] S1. Salt formation reaction

[0018] Add chloroacetic acid to the salt-forming kettle, and add 32% liquid alkali dropwise at 5-30°C to prepare a sodium chloroacetate solution for standby use; add 2,4-dichlorophenol to the salt-forming kettle, raise the temperature to about 45°C, and add 32% liquid alkali dropwise to prepare a sodium 2,4-dichlorophenol solution for standby use.

[0019] S2. Condensation reaction

[0020] The 2,4-dichlorophenol sodium salt solution formed in the previous step is put into a condensation kettle, the temperature is raised to about 80°C, the sodium chloroacetate solution is added dropwise, and the reaction is refluxed at 80°C-110°C for 3 hours. After the reaction is completed, the temperature is lowered and crystallized, and then the 2,4-dichlorophenoxyacetic acid sodium salt crystals are separated by filtration. After two washings, the solid obtained is dried at 70°C under normal pressure to obtain 2,4-dichlorophenoxyacetic acid sodium salt. The condensation reaction yield is 92.54% (calculated based on 2,4-dichlorophenol sodium).

[0021] S3. Mother liquor treatment

[0022] The high-salt mother liquor is acidified with 32% hydrochloric acid (the dissolved part of 2,4-dichlorophenoxyacetic acid sodium in the mother liquor is acidified with hydrochloric acid to convert it into organic matter, which is then extracted and back-extracted). The acidified mother liquor is allowed to stand and then separated. The organic phase is 2,4-dichlorophenol and 2,4-dichlorophenoxyacetic acid, which are recycled. The aqueous phase is high-salt wastewater, which is neutralized to alkalinity, then desalinated by triple-effect evaporation and sent to the sewage station for biochemical treatment.

[0023] S4. Drying

[0024] The wet product of 2,4-dichlorophenoxyacetic acid sodium is dried by air flow, and the dried product is transferred to the packaging equipment through the finished product transfer pump. The hot air in the drying process carries 2,4-dichlorophenoxyacetic acid sodium and is discharged from the upper part of the drying equipment and passes through the bag dust collector. The exhaust gas discharged from the bag dust collector is sprayed with three-level alkaline water and discharged from a 20m high exhaust pipe.

[0025] This project adopts ton bag packaging. The transferred products slowly enter the ton bag. When the product weight reaches 0.8t, the electronic control device will stop transferring and the ton bag will be automatically sealed. When the product slowly enters the ton bag, air will carry the product and be discharged from the top. The discharged waste gas is collected by the bag dust collector. The discharged waste gas and dry waste gas are treated with water spray before being discharged.

[0026] The present application relates to a 2,4-D sodium salt chemical process. The present application uses chloroacetic acid, 2,4-dichlorophenol, 32% liquid alkali, and 32% hydrochloric acid as raw materials, and reacts in a ratio of 6.9:12:23:5.2 to obtain a high-concentration 2,4-D sodium salt with an effective content of up to 99.9%.

[0027] A high-concentration, 2,4-D sodium salt production system, the system comprising a 1# salt-forming kettle, a 2# salt-forming kettle, a condensation kettle, a centrifuge, a mother liquid tank and an acidification kettle, the bottoms of the 1# salt-forming kettle and the 2# salt-forming kettle are respectively connected to the top of the condensation kettle, and the condensation kettle, the centrifuge, the mother liquid tank and the acidification kettle are connected in sequence;

[0028] The top of the No. 1 salt-forming kettle is connected to a liquid alkali high-level tank 1 and a chloroacetic acid feed port, the top of the No. 2 salt-forming kettle is connected to a liquid alkali high-level tank 2 and a 2,4-dichlorophenol feed port, the top of the condensation kettle is connected to a condenser, one side of the top of the acidification kettle is connected to a hydrochloric acid high-level tank, the bottom of the acidification kettle is respectively connected to an oil phase tank and a water phase tank, and the oil phase tank is connected to the top of the No. 2 salt-forming kettle through a feed pump.

[0029] Preferably, the centrifuge comprises a fixing frame and a body shell, a drum is arranged in the body shell, a plurality of groups of centrifugal holes are evenly distributed on the circumferential side wall of the drum, a discharge port is connected to one side of the bottom of the body shell, the discharge port is connected to the top of the mother liquid tank, a cover is arranged on the top of the drum, a top plate is arranged at the bottom of the cover, bolts are respectively threadedly connected on both sides of the top of the cover, and the cover and the top plate are fixed by the bolts;

[0030] A rotating shaft is vertically arranged at the bottom of the rotating drum, and the rotating shaft passes through the outer wall of the downwardly extending end of the fixing frame, and a first gear is sleeved thereon. A second gear is meshedly connected to one side of the first gear, and the second gear is connected to a motor via the rotating shaft.

[0031] Preferably, a filter press plate is provided at the inner bottom of the drum, and a plurality of tiny filter holes are provided on the inner wall of the filter press plate, and the pore size of the filter holes is 0.01-0.03 mm. The upper end surface of the filter press plate is provided as a trapezoidal groove, and the top plate is provided as a corresponding trapezoidal structure, and a movable rod is vertically provided at the bottom of the filter press plate, and a top groove is provided at the downward extending end of the movable rod passing through the rotating shaft, and a T-shaped top block is movably inserted in the top groove, and a piston rod is fixed to the bottom of the T-shaped top block, and a cylinder is connected to the end of the piston rod, and the cylinder is arranged in the mounting frame.

[0032] Preferably, a plurality of groups of limit sliding blocks are evenly distributed on the circumferential side wall of the movable rod, and a movable groove corresponding to the movable rod is provided on the inner wall of the rotating shaft, and a limit sliding groove for sliding the limit sliding block is provided in the movable groove.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The 2,4-D sodium salt (2,4-D sodium salt) in the present invention is a plant growth regulator, which is prepared by reacting 2,4-dichlorophenol, chloroacetic acid, 32% liquid alkali and 32% hydrochloric acid as raw materials in a ratio of 12:6.9:23:5.2. The finished product has a high-concentration 2,4-D sodium salt with an effective content of up to 99.9%, has a good weed control effect and a certain prevention and control effect.

[0035] 2. The centrifuge of the present invention is easy to install and disassemble, and can minimize the filter cake residue, making the collection of the filter cake convenient and quick, thereby increasing the output.

[0036] In summary, the present invention overcomes the shortcomings of the prior art, has a reasonable design, can effectively increase the concentration of 2,4-D sodium salt, has a good weed control effect and a certain control effect, and has a high social use value and application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 is a process flow chart of the present invention;

[0039] Figure 2 It is a schematic diagram of the system structure of the present invention;

[0040] Figure 3 It is a structural schematic diagram of the centrifuge of the present invention;

[0041] Figure 4 It is a schematic cross-sectional diagram of the AA structure of the present invention;

[0042] Figure 5 It is an enlarged schematic diagram of structure B of the present invention.

[0043] In the figure: 1# salt-forming kettle 1, liquid alkali high-level tank 11, 2# salt-forming kettle 2, liquid alkali high-level tank 21, condensation kettle 3, condenser 31, centrifuge 4, fixing frame 41, machine body shell 42, drum 43, centrifugal hole 44, cover 45, top plate 46, bolt 47, filter press plate 48, movable rod 49, rotating shaft 410, first gear 411, second gear 412, motor 413, mounting frame 414, cylinder 415, piston rod 416, T-shaped top block 417, top groove 418, limit slider 419, limit slide 420, mother liquid tank 5, acidification kettle 6, hydrochloric acid high-level tank 61, oil phase tank 62, water phase tank 63. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Example 1

[0046] Reference Figure 1 , a production process of high concentration 2,4-D sodium salt, comprising the following steps:

[0047] S1. Salt formation reaction

[0048] Add 96g of chloroacetic acid to the 500mL salting kettle #1, add 100mL of water, stir to dissolve, keep the temperature in the reactor at 5-30°C, slowly drop 100g of 32% liquid caustic soda, stir to neutralize, and set aside. Add 124g of 2,4-dichlorophenol to the 2000mL salting kettle #2, keep the temperature in the reactor at 45°C, slowly drop 128g of 32% liquid caustic soda, neutralize and set aside. When the pH remains at 9-10 for one hour without changing, the reaction is considered to have reached the end point.

[0049] S2. Condensation reaction

[0050] Heat 224g of material in the 2# salt-forming kettle to 80°C, slowly add 224g of material in the 1# salt-forming kettle to the condensation kettle under stirring, and keep the temperature at 80-110°C for reflux reaction for 3h after the addition is completed. The sample liquid is tested, and the reaction liquid phenol intermediate is less than 3%, which means that the reaction has reached the end point. After the reaction is completed, the material is cooled in the condensation kettle for crystallization and stand-by, and the total yield of the product is 92%.

[0051] S3. Mother liquor treatment

[0052] The mother liquor was condensed and filtered, pumped into the acidification kettle, and 60g of quantitative 32% hydrochloric acid was pumped in. The mixture was stirred for neutralization, and allowed to stand for stratification. The lower aqueous phase was sent to the sewage treatment station for treatment as high-salt wastewater; the upper organic phase was applied to the 2# salt-forming kettle.

[0053] S4. Centrifugation and drying

[0054] The material cooled and crystallized in the condensation kettle is discharged into a closed centrifuge for centrifugal filtration, and the filtrate is collected and sent to the mother liquor treatment process; the filter cake is sent to the drying process and dried in an oven to obtain 188g of product (water content less than 1% is qualified), and the effective content of the finished product reaches 99.8%. The drying tail gas is treated in a bag dust collector and then connected to the workshop exhaust gas treatment system.

[0055] Example 2

[0056] Reference Figure 1 , a production process of high concentration 2,4-D sodium salt, comprising the following steps:

[0057] S1. Salt formation reaction

[0058] Add 69g of chloroacetic acid to the 1#500mL salting kettle, add 100mL of water, stir to dissolve, keep the temperature in the reactor at 5-30℃, slowly drop 110g of 32% liquid caustic soda, stir to neutralize, and set aside. Add 120g of 2,4-dichlorophenol to the 2#2000mL salting kettle, keep the temperature in the reactor at 45℃, slowly drop 120g of 32% liquid caustic soda, neutralize and set aside. When the pH remains at 9-10 for one hour without changing, the reaction is considered to have reached the end point.

[0059] S2. Condensation reaction

[0060] Heat 240g of the material in the 2# salt-forming kettle to 80°C, and slowly add 260g of the material in the 1# salt-forming kettle to the condensation kettle under stirring. After the addition is completed, keep the temperature at 80-110°C for reflux reaction for 3h. The sample liquid is tested. If the phenol intermediate in the reaction liquid is less than 3%, it is considered that the reaction has reached the end point. After the reaction is completed, the material is cooled in the condensation kettle for crystallization and stand-by. The total yield of the product is 96%.

[0061] S3. Mother liquor treatment

[0062] The mother liquor was condensed and filtered, pumped into the acidification kettle, and 52g of quantitative 32% hydrochloric acid was pumped in. The mixture was stirred for neutralization, and allowed to stand for stratification. The lower aqueous phase was sent to the sewage treatment station for treatment as high-salt wastewater; the upper organic phase was applied to the 2# salt-forming kettle.

[0063] S4. Centrifugation and drying

[0064] The material cooled and crystallized in the condensation kettle is discharged into a closed centrifuge for centrifugal filtration, and the filtrate is collected and sent to the mother liquor treatment process; the filter cake is sent to the drying process and dried in an oven to obtain 196g of product (water content less than 1% is qualified), and the effective content of the finished product reaches 99.9%, that is, the purity is 99.9%, and the drying exhaust gas is treated by a bag dust collector and then connected to the workshop exhaust gas treatment system.

[0065] Example 3

[0066] Reference Figure 1 , a production process of high concentration 2,4-D sodium salt, comprising the following steps:

[0067] S1. Salt formation reaction

[0068] Add 89g of chloroacetic acid to the 500mL salting kettle #1, add 100mL of water, stir to dissolve, keep the temperature in the reactor at 5-30°C, slowly drop 130g of 32% liquid caustic soda, stir to neutralize, and set aside. Add 156g of 2,4-dichlorophenol to the 2000mL salting kettle #2, keep the temperature in the reactor at 45°C, slowly drop 130g of 32% liquid caustic soda, neutralize and set aside. When the pH remains at 9-10 for one hour without changing, the reaction is considered to have reached the end point.

[0069] S2. Condensation reaction

[0070] Heat 255g of the material in the 2# salt-forming kettle to 80°C, and slowly add 280g of the material in the 1# salt-forming kettle to the condensation kettle under stirring. After the addition is completed, keep the temperature at 80-110°C for reflux reaction for 3h. The sample liquid is tested. If the phenol intermediate in the reaction liquid is less than 3%, it is considered that the reaction has reached the end point. After the reaction is completed, the material is cooled in the condensation kettle for crystallization and stand-by. The total yield of the product is 95%.

[0071] S3. Mother liquor treatment

[0072] The mother liquor was condensed and filtered, pumped into the acidification kettle, and 52g of quantitative 32% hydrochloric acid was pumped in. The mixture was stirred for neutralization, and allowed to stand for stratification. The lower aqueous phase was sent to the sewage treatment station for treatment as high-salt wastewater; the upper organic phase was applied to the 2# salt-forming kettle.

[0073] S4. Centrifugation and drying

[0074] The material cooled and crystallized in the condensation kettle is discharged into a closed centrifuge for centrifugal filtration, and the filtrate is collected and sent to the mother liquor treatment process; the filter cake is sent to the drying process and dried in an oven to obtain 199g of product (water content less than 1% is qualified), and the effective content of the finished product reaches 99.7%. The drying exhaust gas is treated in a bag dust collector and then connected to the workshop exhaust gas treatment system.

[0075] 2,4-D sodium salt production material balance table (t / a)

[0076]

[0077] Example 4

[0078] Reference Figure 2-5 A high-concentration 2,4-D sodium salt production system, the system includes a 1# salt-forming kettle 1, a 2# salt-forming kettle 2, a condensation kettle 3, a centrifuge 4, a mother liquid tank 5 and an acidification kettle 6, the bottoms of the 1# salt-forming kettle 1 and the 2# salt-forming kettle 2 are respectively connected to the top of the condensation kettle 3, and the condensation kettle 3, the centrifuge 4, the mother liquid tank 5 and the acidification kettle 6 are connected in sequence;

[0079] The top of the 1# salt-forming kettle 1 is connected to a liquid alkali high-level tank 11 and a chloroacetic acid feed port, the top of the 2# salt-forming kettle 2 is connected to a liquid alkali high-level tank 21 and a 2,4-dichlorophenol feed port, the top of the condensation kettle 3 is connected to a condenser 31, one side of the top of the acidifying kettle 6 is connected to a hydrochloric acid high-level tank 61, and the bottom of the acidifying kettle 6 is respectively connected to an oil phase tank 62 and a water phase tank 63, and the oil phase tank 62 is connected to the top of the 2# salt-forming kettle 2 through a material pump.

[0080] The centrifuge 4 includes a fixing frame 41 and a body shell 42. A drum 43 is arranged in the body shell 42. A plurality of groups of centrifugal holes 44 are evenly distributed on the circumferential side wall of the drum 43. A discharge port is connected to one side of the bottom of the body shell 42. The discharge port is connected to the top of the mother liquid tank 5. A cover 45 is arranged on the top of the drum 43. A top plate 46 is arranged at the bottom of the cover 45. Bolts 47 are respectively threadedly connected on both sides of the top of the cover 45. The cover 45 and the top plate 46 are fixed by the bolts 47.

[0081] A rotating shaft 410 is vertically provided at the bottom of the rotating drum 43. The rotating shaft 410 passes through the outer wall of the downwardly extending end of the fixing frame 41 and is sleeved with a first gear 411. A second gear 412 is meshedly connected to one side of the first gear 411. The second gear 412 is connected to a motor 413 through a rotating shaft. When the motor 413 is started, the motor 413 drives the second gear 412 to rotate through the rotating shaft. The second gear 412 drives the first gear 411 to rotate. The first gear 411 drives the rotating shaft 410 to rotate. The rotating shaft 410 is clamped in the limiting sliding groove 420 through the limiting sliding block 419 on the inner wall, thereby driving the movable rod 49 to rotate, thereby making the rotating shaft 410 rotate. The drum 43 and the filter press plate 48 inside can centrifuge the material. The mother liquid enters the mother liquid tank 5 through the discharge port, and the filter material falls onto the filter press plate 48. At this time, the cylinder 415 is started again. The cylinder 415 pushes the T-shaped top block 417 upward through the piston rod 416. When the T-shaped top block 417 is pushed upward, it is clamped into the top groove 418, thereby pushing the movable rod 49 upward. The filter press plate 48 presses the filter material upward and finally forms a filter cake. Thereafter, the bolts 47 are loosened and the cover 45 is disassembled, thereby facilitating the collection of the filter cake. The operation is more convenient and quick, and the residue of the filter cake is greatly reduced, thereby improving the output.

[0082] A filter press plate 48 is provided at the inner bottom of the drum 43, and a plurality of tiny filter holes are provided on the inner wall of the filter press plate 48, and the pore size of the filter holes is 0.01-0.03 mm. The upper end surface of the filter press plate 48 is provided with a trapezoidal groove, and the top plate 46 is provided with a corresponding trapezoidal structure. A movable rod 49 is vertically provided at the bottom of the filter press plate 48, and a plurality of groups of limit sliders 419 are evenly distributed on the circumferential side wall of the movable rod 49. A movable groove corresponding to the movable rod 49 is provided on the inner wall of the rotating shaft 410, and a limit slide groove 420 for the limit slider 419 to slide is provided in the movable groove.

[0083] The movable rod 49 passes through the rotating shaft 410 and is provided with a top groove 418 at the downward extending end. A T-shaped top block 417 is movably inserted in the top groove 418. A piston rod 416 is fixed to the bottom of the T-shaped top block 417. The end of the piston rod 416 is connected to a cylinder 415, and the cylinder 415 is arranged in the mounting frame 414.

[0084] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0085] In the present invention, unless otherwise clearly specified and limited, the terms "set", "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0086] The control method of the present invention is automatic control through a controller. The control circuit of the controller can be implemented by simple programming by technicians in this field. The provision of power is also common knowledge in this field. The present invention is mainly used to protect mechanical devices, so the present invention will no longer explain the control method and circuit connection in detail.

[0087] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A production process for high-concentration 2,4-D sodium salt, characterized in that: The following steps are involved: S1. Salt formation reaction Add 96g of chloroacetic acid to a 500mL 1# salt-forming kettle, add 100mL of water, stir to dissolve, keep the temperature in the reactor at 5-30°C, slowly drop 100g of 32% liquid caustic soda, stir to neutralize, and set aside; add 124g of 2,4-dichlorophenol to a 2000mL 2# salt-forming kettle, keep the temperature in the reactor at 45°C, slowly drop 128g of 32% liquid caustic soda, neutralize and set aside, when the pH remains at 9-10 for one hour without changing, the reaction is considered to have reached the end point; S2. Condensation reaction Heat 224g of the material in the 2# salt-forming kettle to 80°C, and slowly drop 224g of the material in the 1# salt-forming kettle into the condensation kettle under stirring. After the addition is completed, keep the temperature at 80-110°C and reflux for 3h; take a sample for testing, and if the phenol intermediate in the reaction liquid is less than 3%, it is considered that the reaction has reached the end point; after the reaction is completed, cool the material in the condensation kettle for crystallization and set aside, and the total yield of the product is 92%; S3. Mother liquor treatment The mother liquor was condensed and filtered, and pumped into the acidification kettle. 60g of quantitative 32% hydrochloric acid was pumped in, stirred and neutralized, and allowed to stand for stratification. The lower aqueous phase was sent to the sewage treatment station for treatment as high-salt wastewater; the upper organic phase was applied to the 2# salting kettle; S4. Centrifugation and drying The material cooled and crystallized in the condensation kettle is discharged into a closed centrifuge for centrifugal filtration, and the filtrate is collected and sent to the mother liquor treatment process; the filter cake is sent to the drying process and dried in an oven to obtain 188g of product, and the effective content of the finished product reaches 99.8%. The drying tail gas is treated by a bag dust collector and then connected to the workshop exhaust gas treatment system; The production process further comprises the following production system, the production system comprising a No. 1 salt-forming kettle (1), a No. 2 salt-forming kettle (2), a condensation kettle (3), a centrifuge (4), a mother liquor tank (5) and an acidification kettle (6), the bottoms of the No. 1 salt-forming kettle (1) and the No. 2 salt-forming kettle (2) being respectively connected to the top of the condensation kettle (3), and the condensation kettle (3), the centrifuge (4), the mother liquor tank (5) and the acidification kettle (6) being connected in sequence; The top of the No. 1 salt-forming kettle (1) is connected to a first high-level liquid alkali tank (11) and a chloroacetic acid feed port, the top of the No. 2 salt-forming kettle (2) is connected to a second high-level liquid alkali tank (21) and a 2,4-dichlorophenol feed port, the top of the condensation kettle (3) is connected to a condenser (31), one side of the top of the acidification kettle (6) is connected to a hydrochloric acid high-level tank (61), the bottom of the acidification kettle (6) is respectively connected to an oil phase tank (62) and a water phase tank (63), and the oil phase tank (62) is connected to the top of the No. 2 salt-forming kettle (2) via a feed pump; The centrifuge (4) comprises a fixing frame (41) and a machine body shell (42). A rotating drum (43) is arranged in the machine body shell (42). A plurality of groups of centrifugal holes (44) are evenly distributed on the circumferential side wall of the rotating drum (43). A discharge port is connected to one side of the bottom of the machine body shell (42). The discharge port is connected to the top of the mother liquid tank (5). A sealing cover (45) is arranged on the top of the rotating drum (43). A top plate (46) is arranged at the bottom of the sealing cover (45). Bolts (47) are respectively threadedly connected to the two sides of the top of the sealing cover (45). The sealing cover (45) and the top plate (46) are fixed by the bolts (47). A rotating shaft (410) is vertically provided at the bottom of the rotating drum (43). The rotating shaft (410) passes through the outer wall of the downwardly extending end of the fixing frame (41) and is sleeved with a first gear (411). A second gear (412) is meshedly connected to one side of the first gear (411). The second gear (412) is connected to a motor (413) via a rotating shaft. When the motor (413) is started, the motor (413) drives the second gear (412) to rotate via the rotating shaft. The second gear (412) drives the first gear (411) to rotate. The first gear (411) drives the rotating shaft (410) to rotate. The rotating shaft (410) is clamped in the limiting sliding groove (420) via a limiting sliding block (419) on the inner wall, thereby driving the movable rod (49) to rotate. , so that the drum (43) and the filter press plate (48) inside can centrifugally separate the material, the mother liquid enters the mother liquid tank (5) through the discharge port, and the filter material falls onto the filter press plate (48). At this time, the cylinder (415) is started again, and the cylinder (415) pushes the T-shaped top block (417) upward through the piston rod (416). When the T-shaped top block (417) is pushed upward, it is clamped into the top groove (418), thereby pushing the movable rod (49) upward, and the filter press plate (48) presses the filter material upward to finally form a filter cake. Thereafter, the bolt (47) is loosened and the cover (45) is disassembled, thereby facilitating the collection of the filter cake, making the operation more convenient and quick, and greatly reducing the residue of the filter cake, thereby improving the yield; A filter press plate (48) is provided at the inner bottom of the drum (43), and a plurality of tiny filter holes are provided on the inner wall of the filter press plate (48), and the pore size of the filter holes is 0.01-0.03 mm. The upper end surface of the filter press plate (48) is provided with a trapezoidal groove, and the top plate (46) is provided with a corresponding trapezoidal structure. A movable rod (49) is vertically provided at the bottom of the filter press plate (48), and a plurality of groups of limit sliders (419) are evenly distributed on the circumferential side wall of the movable rod (49). A movable groove corresponding to the movable rod (49) is provided on the inner wall of the rotating shaft (41) 0, and a limit slide groove (420) for sliding the limit slider (419) is provided in the movable groove. A movable rod (49) passes through the rotating shaft (410) and is provided with a top groove (418) at the downwardly extending end thereof. A T-shaped top block (417) is movably inserted in the top groove (418). A piston rod (416) is fixed to the bottom of the T-shaped top block (417). The end of the piston rod (416) is connected to a cylinder (415). The cylinder (415) is arranged in a mounting frame (414).

Images