A synthesis system and method of a water-in-oil polyacrylamide emulsion

Abstract

The application provides a water-in-oil polyacrylamide emulsion synthesis system, which comprises a batching unit, a reaction unit and a cooling module; the batching unit comprises a batching tank, a first stirring motor and a metering pump; the reaction unit comprises a reaction kettle, a second stirring motor module and a concentric double-shaft stirrer arranged in the reaction kettle; the cooling module is communicated with the reaction unit and the batching unit through pipelines; the concentric double-shaft stirrer is composed of a blade stirring paddle, a spiral stirring paddle, an anchor stirring paddle and an emulsifying head; the concentric double-shaft stirrer is connected with the second stirring motor module; the blade stirring paddle, the spiral stirring paddle, the anchor stirring paddle and the emulsifying head move synchronously under the driving of the second stirring motor module. The concentric double-shaft stirrer can fully mix and uniformly distribute the emulsion in the tank, rapidly dissipate heat and improve the quality of the polyacrylamide product.

Description

Technical Field

[0001] This invention belongs to the field of polyacrylamide synthesis technology, and particularly relates to a synthesis system and method for a water-in-oil polyacrylamide emulsion. Background Technology

[0002] Polyacrylamide emulsions are generally homogeneous emulsion systems formed by dispersing aqueous solutions of monomers in an oil phase with the aid of surfactants and strong homogenizers. Emulsion polymerization then occurs under the action of deoxygenation and initiators, resulting in stable polyacrylamide emulsion products of varying molecular weights. Current research on polyacrylamide emulsion polymerization largely focuses on improving the composition to increase the relative molecular mass of the polymer. However, the emulsion polymerization process is significantly affected by two-phase homogenization and temperature rise. Laboratory-scale synthesis typically does not consider sufficient homogenization and heat dissipation at large scales. In large-scale synthesis, the inability to ensure adequate mixing and heat dissipation of the emulsion will inevitably affect the quality of the final polyacrylamide emulsion product. Summary of the Invention

[0003] This invention provides a synthesis system and method for water-in-oil polyacrylamide emulsions, aiming to solve the problem that current laboratory-scale equipment cannot meet the homogenization and heat dissipation requirements of large-volume polyacrylamide emulsion products.

[0004] This invention is achieved by providing a synthesis system for a water-in-oil polyacrylamide emulsion, comprising:

[0005] A batching unit, comprising a mixing tank, a first stirring motor, and a metering pump;

[0006] The reaction unit includes a reaction vessel, a second stirring motor module, and a concentric twin-shaft stirrer located inside the reaction vessel.

[0007] A cooling module is connected to the reaction unit and the batching unit via pipes;

[0008] The concentric dual-shaft mixer consists of a blade-type impeller, a spiral impeller, an anchor-type impeller, and an emulsifying head. The concentric dual-shaft mixer is connected to a second mixing motor module. The blade-type impeller, spiral impeller, anchor-type impeller, and emulsifying head move synchronously under the drive of the second mixing motor module.

[0009] Preferably, the reactor is provided with a reactor lid, the second stirring motor module is provided on the reactor lid, the concentric biaxial stirrer is connected to the second stirring motor module, the prepared oil phase liquid is added into the reactor, the aqueous solution continuously transported from the preparation tank is mixed with the oil phase liquid in the reactor, and a uniform water-in-oil emulsion is formed under the high-speed shearing action of the concentric biaxial stirrer before polymerization.

[0010] Preferably, the concentric biaxial stirrer further includes an outer shaft and an inner shaft, with the outer shaft wrapping around the outside of the inner shaft. The blade-type stirring paddle is located on the outer shaft near the reactor lid, the spiral stirring paddle is located on the outer wall of the outer shaft, the anchor-type stirring paddle is connected to the end of the outer shaft away from the reactor lid, and the emulsifying head is located at the end of the concentric biaxial stirrer near the bottom of the reactor.

[0011] Preferably, the emulsifying head includes an outer shaft and an inner shaft; the outer shaft and the inner shaft are nested together, the outer shaft is connected to the end of the outer shaft, and the inner shaft is connected to the end of the inner shaft. The rotational speed difference between the outer shaft and the inner shaft causes a rotational speed difference between them, so that the originally immiscible oil phase and water phase form a uniform water-in-oil emulsion under the action of the emulsifier.

[0012] Preferably, the second stirring motor module includes:

[0013] An external shaft control motor is provided with a first rotating shaft, and a driving gear is provided at the end of the first rotating shaft. The driving gear meshes with a driven gear provided on the outer wall of the external shaft.

[0014] An inner shaft control motor is provided, and a second rotating shaft is provided on the inner shaft control motor, the second rotating shaft being connected to the inner shaft.

[0015] Preferably, the preparation tank is provided with a first control panel, and the preparation tank is provided with a pH detection sensor and a temperature sensor. The first control panel is electrically connected to the first stirring motor, the pH detection sensor and the temperature sensor.

[0016] Preferably, the reaction unit further includes a second control panel, and the reactor is also equipped with a temperature sensor. The second control panel is electrically connected to the second stirring motor module and the temperature sensor.

[0017] A method for synthesizing a water-in-oil polyacrylamide emulsion, wherein the synthesis method is carried out in the water-in-oil polyacrylamide emulsion synthesis system described above, and the synthesis method includes:

[0018] Step 1: Preparation of aqueous solution

[0019] Turn on the water circulation cooling device and adjust the cooling water to a certain temperature for later use; add a certain proportion of monomer, pure water and regulator to the preparation tank, start the first stirring motor through the knob on the first control panel to make it completely dissolved, use the cooling water of the water circulation cooling device to stabilize the temperature in the preparation tank, then add alkali solution to the solution, the pH of the solution can be monitored through the first control panel until the pH is adjusted to neutral, and then stop the cooling water circulation.

[0020] Step 2: Formation of water-in-oil emulsion

[0021] Add the prepared oil phase liquid to the reactor. Adjust the inner and outer shaft speeds of the concentric twin-shaft stirrer to the predetermined values ​​through the second control panel. Turn on the metering pump and pump the aqueous solution in the preparation tank into the reactor through the feed port at a certain flow rate. Under the strong shearing action of the outer shaft and inner shaft of the emulsifying head, the originally immiscible water phase and oil phase form a stable water-in-oil emulsion. Under the action of the combined stirring paddle, the emulsion is quickly and evenly mixed in the reactor.

[0022] Step 3: Initiate aggregation

[0023] Seal the feed inlet, open the exhaust pipe on the reactor, and introduce nitrogen into the reactor for a period of time to remove the liquid phase and oxygen from the air. Turn on the water circulation cooling device to remove the heat from the tank. When the emulsion temperature in the reactor reaches the predetermined value, slowly add an initiator of a certain concentration through the dosing port to initiate polymerization.

[0024] Step 4: Emulsion Phase Inversion

[0025] After the temperature inside the reactor drops to room temperature, add a certain amount of phase inversion agent through the feed inlet and continue stirring for a certain period of time to ensure that the phase inversion agent and the emulsion are mixed evenly.

[0026] Stop stirring, open the outlet at the bottom of the reactor to discharge the emulsion, and obtain the target product.

[0027] Preferably, the regulator includes chain transfer agents, chelating agents, and dispersants;

[0028] Preferably, the outer shaft stirring speed is 200-500 r / min, the inner shaft stirring speed is 1000-2500 r / min, the homogenization time is 7-10 min, and the inner shaft stirring speed is 5-10 times that of the outer shaft stirring speed;

[0029] Preferably, the temperature of the material in the reactor before the initiator is added is set to 10-20°C, the initiator is added for about 2 hours, and the polymerization reaction lasts for about 4-6 hours.

[0030] Compared with the prior art, the embodiments of this application have the following main advantages:

[0031] 1. The synthesis system and method for water-in-oil polyacrylamide emulsion provided by the present invention can achieve homogenization of the oil phase and water phase and emulsion polymerization in the same reactor through the action of a concentric biaxial stirrer. After the water-in-oil emulsion is formed, the polymerization reaction can be directly initiated in situ, saving space and avoiding the impact of further transportation on the stability of the water-in-oil emulsion.

[0032] 2. The synthesis system and method for water-in-oil polyacrylamide emulsion provided by the present invention can fully mix the emulsion in the tank and dissipate heat quickly through the combined stirring paddle, avoiding the product quality degradation caused by the large temperature difference between the emulsion on the outside and the center of the tank and uneven heat dissipation due to traditional stirring methods. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the synthesis system and method for a water-in-oil polyacrylamide emulsion provided by the present invention.

[0034] Figure 2 This is a schematic diagram of the reaction unit structure of the synthesis system and synthesis method for a water-in-oil polyacrylamide emulsion provided by the present invention.

[0035] Figure 3 This is a schematic diagram of the second stirring motor module structure in the synthesis system and synthesis method of a water-in-oil polyacrylamide emulsion provided by the present invention.

[0036] Figure 4 This is a schematic diagram of the emulsifying head structure in the synthesis system and method for a water-in-oil polyacrylamide emulsion provided by the present invention.

[0037] Figure 5 This is a schematic diagram of the outer shaft structure of the emulsifying head in the synthesis system and method for a water-in-oil polyacrylamide emulsion provided by the present invention.

[0038] Figure 6 This is a schematic diagram of the inner shaft structure of the emulsifying head in the synthesis system and method for a water-in-oil polyacrylamide emulsion provided by the present invention.

[0039] Figure 7 This is a schematic diagram of material movement at the emulsification head structure in the synthesis system and method for a water-in-oil polyacrylamide emulsion provided by the present invention.

[0040] 110. Preparation tank; 111. Cooling water outlet of preparation tank; 112. Cooling water inlet of preparation tank; 120. Support plate; 130. First stirring motor; 140. Metering pump; 150. First control panel;

[0041] 210. Water circulation cooling device; 211. Heat dissipation vent; 212. Cooling water tee outlet; 213. Cooling water tee inlet; 220. Cooling water controller;

[0042] 310. Reactor; 311. Second cooling water layer; 312. Feed inlet; 313. Discharge outlet; 314. Chemical dosing port; 315. Temperature sensor sleeve; 316. Reactor cooling water outlet; 317. Reactor cooling water inlet; 318. Exhaust pipe; 319. Nitrogen pipe; 320. Support; 330. Reactor cover; 340. Second stirring motor module; 341. Outer shaft control motor; 342. First rotating shaft; 343. Drive gear; 344. Driven gear; 345. Sliding bearing; 346. Fixed rod; 347. Inner shaft control motor; 348. Second rotating shaft; 350. Second control panel;

[0043] 400. Concentric twin-shaft agitator; 401. Outer shaft; 402. Inner shaft; 410. Blade-type agitator; 420. Spiral agitator; 430. Anchor-type agitator; 440. Emulsifying head; 441. Outer shaft of emulsifying head; 442. Inner shaft of emulsifying head. Detailed Implementation

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0045] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0046] This invention provides a synthesis system for water-in-oil polyacrylamide emulsions, such as... Figures 1-7 As shown, the synthesis system for the water-in-oil polyacrylamide emulsion includes:

[0047] The batching unit includes a mixing tank 110, a first stirring motor 130, and a metering pump 140.

[0048] The reaction unit includes a reaction vessel 310, a second stirring motor module 340, and a concentric twin-shaft stirrer 400 disposed inside the reaction vessel 310.

[0049] A cooling module is connected to the reaction unit and the batching unit via pipes;

[0050] The concentric dual-shaft mixer 400 is composed of a blade-type mixing blade 410, a spiral mixing blade 420, an anchor-type mixing blade 430, and an emulsifying head 440. The concentric dual-shaft mixer 400 is connected to a second mixing motor module 340. The blade-type mixing blade 410, spiral mixing blade 420, anchor-type mixing blade 430, and emulsifying head 440 move synchronously under the drive of the second mixing motor module 340.

[0051] In this embodiment, the preparation tank 110 is provided with a support plate 120, and the top of the preparation tank 110 has an open structure. The first stirring motor 130 is mounted on the support plate 120, and the end of the first stirring motor 130 is provided with a stirring paddle. A certain proportion of monomer, pure water and regulator are injected into the preparation tank 110 from the top. Under the stirring action of the stirring paddle, an aqueous solution is formed. The inlet end of the metering pump 140 provided on the support plate 120 extends into the bottom of the preparation tank 110. The metering pump 140 transports the aqueous solution inside the preparation tank 110 to the reaction vessel 310 through a pipeline.

[0052] The reaction unit also includes a support 320, the reaction vessel 310 is mounted on the support 320, the reaction vessel 310 is provided with a reaction vessel cover 330, the second stirring motor module 340 is provided on the reaction vessel cover 330, the concentric biaxial stirrer 400 is connected to the second stirring motor module 340, the prepared oil phase liquid is added into the reaction vessel 310, and the aqueous solution continuously transported by the preparation tank 110 and the oil phase liquid form a uniform water-in-oil emulsion under the high-speed shearing action of the concentric biaxial stirrer 400 and then polymerize;

[0053] The concentric biaxial stirrer 400 further includes an outer shaft 401 and an inner shaft 402. The outer shaft 401 wraps around the outside of the inner shaft 402. The blade-type stirring paddle 410 is located on the outer shaft 401 near the reactor cover 330. The spiral stirring paddle 420 is located on the outer wall of the outer shaft 401. The anchor-type stirring paddle 430 is connected to the end of the outer shaft 401 away from the reactor cover 330. The emulsifying head 440 includes an emulsifying head outer shaft 441 and an emulsifying head inner shaft 442. The emulsifying head outer shaft 441 and the emulsifying head inner shaft 442 are respectively located on the outer shaft 401 and the inner shaft 402. On 02, a shearing action is generated under the staggered rotation effect of the outer shaft 401 and the inner shaft 402. The concentric dual-shaft stirrer 400 is formed by four sets of structures, which form different stirring effects from top to bottom inside the reactor 310. The blade-type stirring paddle 410 quickly disperses the aqueous solution input by the metering pump 140. Under the transmission action of the spiral stirring paddle 420, the aqueous solution moves from bottom to top and diffuses into the reactor 310. The anchor-type stirring paddle 430 drives the material outside the tank to move inward, while the emulsifying head 440 performs high-speed shearing on the aqueous solution and the oil phase.

[0054] In this embodiment, the cooling module includes a water circulation cooling device 210, and a cooling water controller 220 is provided on the water circulation cooling device 210; the water circulation cooling device 210 is provided with a cooling water tee outlet 212 and a cooling water tee inlet 213, and the cooling water tee outlet 212 and the cooling water tee inlet 213 are respectively connected to the condensation system on the preparation tank 110 and the reaction vessel 310 through pipelines;

[0055] In a preferred embodiment of this invention, the second stirring motor module 340 includes:

[0056] An outer shaft control motor 341 is provided with a first rotating shaft 342, and a drive gear 343 is provided at the end of the first rotating shaft 342. The drive gear 343 is meshed with a driven gear 344 provided on the outer wall of the outer shaft 401.

[0057] An inner shaft control motor 347 is provided with a second rotating shaft 348, which is connected to the inner shaft 402;

[0058] In this embodiment, the outer shaft control motor 341, the inner shaft control motor 347, and related auxiliary equipment constitute a second stirring motor module 340. The second stirring motor module 340 is also provided with a housing. The outer wall of the outer shaft 401 is also provided with a sliding bearing 345. The sliding bearing 345 is connected to a fixing rod 346 provided on the housing. The outer shaft 401 is connected to the second stirring motor module 340 through the fixing rod 346 and the sliding bearing 345. The outer shaft control motor 341 and the inner shaft control motor 347 adopt existing technology, and the rotational speed of the outer shaft 401 and the inner shaft 402 can be changed by controlling the outer shaft control motor 341 and the inner shaft control motor 347.

[0059] Furthermore, the outer shaft control motor 341 is connected to the driving gear 343 via the first rotating shaft 342. The driving gear 343 is meshed with the driven gear 344. When the outer shaft control motor 341 starts working, the first rotating shaft 342 and the driving gear 343 start to rotate, thereby driving the driven gear 344 to rotate. The driven gear 344 is located on the outer wall of the outer shaft 401. The rotation of the driven gear 344 drives the outer shaft 401 to rotate.

[0060] Furthermore, the inner shaft control motor 347 is connected to the inner shaft 402 via the second rotating shaft 348. When the inner shaft control motor 347 starts working, it drives the second rotating shaft 348 and the inner shaft 402 directly connected to the second rotating shaft 348 to start rotating.

[0061] The two independent motors can use independent power supplies and controllers, or they can be implemented by sharing a power supply and controller. By selecting appropriate motor types and specifications to meet the power requirements and speed range of the inner shaft 402 and the outer shaft 401, the speed can be adjusted using a motor controller or speed regulator.

[0062] In a preferred embodiment of this invention, the preparation tank 110 has a first cooling water layer inside its body; the inlet of the first cooling water layer is connected to the outlet 212 of the cooling water tee, and the outlet of the first cooling water layer is connected to the inlet of the inlet 213 of the cooling water tee; the preparation tank 110 is equipped with a pH detection sensor and a temperature sensor; and the preparation tank 110 is also equipped with a first control panel 150 on its outside, which is electrically connected to the pH detection sensor and the temperature sensor.

[0063] In this embodiment, the interior of the preparation tank 110 is hollow, and the first cooling water layer is located inside the tank wall; the water circulation cooling device 210 absorbs the heat of the preparation tank 110 by injecting circulating cooling water into the first cooling water layer, keeping the aqueous solution at a constant temperature, and forming an aqueous solution with a suitable pH value by adding alkali solution.

[0064] In a preferred embodiment of this invention, the top of the reactor 310 is provided with a feed inlet 312; the outlet of the metering pump 140 is connected to the feed inlet 312 via a pipe; the bottom of the reactor 310 is provided with a discharge outlet 313; the reactor cover 330 is also provided with a dosing port 314 and a temperature sensor sleeve 315; and the reaction unit also includes a second control panel 350.

[0065] In this embodiment, the second control panel 350 is connected to a temperature sensor inserted into the reactor 310 through a temperature sensor sleeve 315, and the second control panel 350 is electrically connected to the second stirring motor module 340.

[0066] In a preferred embodiment of this invention, the reactor 310 has a second cooling water layer 311 inside its body, and the reactor 310 has a reactor cooling water outlet 316 and a reactor cooling water inlet 317, which are connected to the second cooling water layer 311.

[0067] In this embodiment, the reactor cooling water inlet 317 is located at the bottom of the reactor body 310, and the reactor cooling water outlet 316 is located at the top of the reactor body 310; the reactor 310 is also provided with an exhaust pipe 318 and a nitrogen pipe 319, the nitrogen pipe 319 is connected to a nitrogen equipment, and the oxygen content in the reactor 310 is reduced by injecting nitrogen;

[0068] In a preferred embodiment of this invention, the emulsifying head 440 includes an outer shaft 441 and an inner shaft 442; the outer shaft 441 and the inner shaft 442 are nested together, with the outer shaft 441 connected to the end of the outer shaft 441 and the inner shaft 442 connected to the end of the inner shaft 442.

[0069] In a further preferred embodiment of the present invention, the rotational speed difference between the outer shaft 401 and the inner shaft 402 causes a rotational speed difference between the outer shaft 441 and the inner shaft 442 of the emulsifying head, so that the originally immiscible oil phase and water phase form a uniform water-in-oil emulsion in the presence of the emulsifier.

[0070] This invention also provides a method for synthesizing a water-in-oil polyacrylamide emulsion, wherein the synthesis method is carried out in the water-in-oil polyacrylamide emulsion synthesis system described above, and the synthesis method includes:

[0071] Step 1: Preparation of aqueous solution

[0072] Open the control panel of the water circulation cooling device 210 and adjust the cooling water to a certain temperature for later use. Add a certain proportion of monomer, pure water, and regulator to the preparation tank 110. The regulator includes chain transfer agent, chelating agent, and dispersant. Start the first stirring motor 130 by turning the knob on the first control panel 150 to dissolve the monomer completely. Open the cooling water tee outlet 212 of the water circulation cooling device 210 to start the circulation. The circulating cold water enters through the cooling water inlet 112 at the lower end of the preparation tank 110 and exits through the cooling water outlet 111, returning to the water circulation cooling device 210. Then, add alkali solution to the solution. The pH of the solution can be monitored through the first control panel 150 until the pH is adjusted to neutral. Then, stop the cooling water circulation.

[0073] Step 2: Formation of water-in-oil emulsion

[0074] The prepared oil phase liquid is added to the reactor 310. The rotation speed of the inner shaft 402 and outer shaft 401 of the concentric twin-shaft stirrer 400 is adjusted to a predetermined value through the second control panel 350. The metering pump 140 is turned on and the aqueous solution in the preparation tank 110 is pumped into the reactor through the feed port 312 at a certain flow rate. Under the strong shearing action of the outer shaft 441 and inner shaft 442 of the emulsifying head, the originally immiscible water phase and oil phase form a stable water-in-oil emulsion. Under the action of the combined stirring paddle, the emulsion is quickly and evenly mixed in the reactor.

[0075] Step 3: Initiate aggregation

[0076] Seal the feed inlet 312, open the exhaust pipe 318 on the reactor 310, and introduce nitrogen into the reactor 310 for a period of time to remove the liquid phase and oxygen from the air. Turn on the cooling water outlet 212 of the water circulation cooling device 210, and let the circulating cooling water enter from the reactor cooling water inlet 317 at the bottom of the reactor and exit from the reactor cooling water outlet 316 to remove the heat in the tank. When the emulsion temperature in the reactor 310 reaches the predetermined value, slowly add an initiator of a certain concentration through the dosing port 314 to initiate polymerization.

[0077] The temperature of the material in the reactor before the initiator is added is set to 10-20°C, the initiator is added for about 2 hours, and the polymerization reaction lasts for about 4-6 hours.

[0078] The polymerization reaction is an exothermic process. The emulsion can be fully mixed in the tank by the action of the stirrer outer shaft 401 combined with the stirring paddle. The anchor-type stirring paddle drives the emulsion on the outside of the tank to move inward, and the spiral stirring paddle drives the emulsion in the tank to move from bottom to top, promoting uniform heat dissipation in all parts of the reactor 310. When the temperature in the reactor 310 rises to the peak and begins to drop, the cooling water circulation is stopped, and stirring continues until the reaction is complete.

[0079] Step 4: Emulsion Phase Inversion

[0080] After the temperature inside the reactor 310 drops to room temperature, a certain amount of phase inversion agent is added through the feed inlet 312, and stirring is continued for a certain period of time to ensure that the phase inversion agent and the emulsion are mixed evenly.

[0081] Stop stirring, open the discharge port 313 at the lower end of the reaction vessel 310 to discharge the emulsion, and obtain the target product.

[0082] In this embodiment, the stirring speed of the outer shaft 401 is 200-500 r / min, the stirring speed of the inner shaft 402 is 1000-2500 r / min, the homogenization time is 7-10 min, and the stirring speed of the inner shaft 402 is 5-10 times that of the stirring speed of the outer shaft 401; the regulator includes chain transfer agents, chelating agents, and dispersants;

[0083] It should be noted that, for the sake of simplicity, the foregoing embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0084] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still combine, add, delete, or otherwise adjust the features of the various embodiments of the present invention according to the circumstances without conflict or creative effort, thereby obtaining different technical solutions that do not fundamentally depart from the concept of the present invention. These technical solutions also fall within the scope of protection of the present invention.

Claims

1. A method for synthesizing a water-in-oil polyacrylamide emulsion, characterized in that, A synthesis system for water-in-oil polyacrylamide emulsions is used, the system comprising: A batching unit, comprising a mixing tank, a first stirring motor, and a metering pump; The reaction unit includes a reaction vessel, a second stirring motor module, and a concentric twin-shaft stirrer located inside the reaction vessel. A cooling module is connected to the reaction unit and the batching unit via pipes; The concentric dual-shaft mixer is composed of a blade-type mixing blade, a spiral mixing blade, an anchor-type mixing blade, and an emulsifying head. The concentric dual-shaft mixer is connected to a second mixing motor module. The blade-type mixing blade, spiral mixing blade, anchor-type mixing blade, and emulsifying head move synchronously under the drive of the second mixing motor module. The preparation tank is equipped with a first control panel, and a pH sensor and a temperature sensor are installed inside the preparation tank. The first control panel is electrically connected to a first stirring motor, the pH sensor, and the temperature sensor. The reaction unit also includes a second control panel, and a temperature sensor is installed inside the reaction vessel. The second control panel is electrically connected to a second stirring motor module and the temperature sensor. The method for synthesizing the water-in-oil polyacrylamide emulsion includes: Step 1: Preparation of aqueous solution Turn on the water circulation cooling device and adjust the cooling water to a certain temperature for later use; add a certain proportion of monomer, pure water and regulator to the preparation tank, the regulator including chain transfer agent, chelating agent and dispersant; start the first stirring motor by turning the knob on the first control panel to make it completely dissolved, use the cooling water of the water circulation cooling device to stabilize the temperature in the preparation tank, then add alkaline solution to the solution, monitor the pH of the solution through the first control panel until the pH is adjusted to neutral, and stop the cooling water circulation; Step 2: Formation of water-in-oil emulsion Add the prepared oil phase liquid to the reactor. Adjust the inner and outer shaft speeds of the concentric twin-shaft stirrer to the predetermined values ​​through the second control panel. Turn on the metering pump and pump the aqueous solution in the preparation tank into the reactor through the feed port at a certain flow rate. Under the strong shearing action of the outer shaft and inner shaft of the emulsifying head, the originally immiscible water phase and oil phase form a stable water-in-oil emulsion. Under the action of the combined stirring paddle, the emulsion is quickly and evenly mixed in the reactor. Step 3: Initiate aggregation Seal the feed inlet, open the exhaust pipe on the reactor, and introduce nitrogen into the reactor for a period of time to remove the liquid phase and oxygen from the air. Turn on the water circulation cooling device to remove the heat from the tank. When the emulsion temperature in the reactor reaches the predetermined value, slowly add a certain concentration of initiator through the dosing port to initiate the polymerization reaction. Step 4: Emulsion Phase Inversion After the temperature inside the reactor drops to room temperature, add a certain amount of phase inversion agent through the feed inlet and continue stirring for a certain period of time to ensure that the phase inversion agent and the emulsion are mixed evenly. Stop stirring, open the outlet at the bottom of the reactor to discharge the emulsion, and obtain the target product.

2. The method for synthesizing a water-in-oil polyacrylamide emulsion as described in claim 1, characterized in that, The reactor is equipped with a reactor lid, and the second stirring motor module is located on the reactor lid. The concentric biaxial stirrer is connected to the second stirring motor module. The prepared oil phase liquid is added into the reactor. The aqueous solution continuously transported from the preparation tank is mixed with the oil phase liquid in the reactor and forms a uniform water-in-oil emulsion under the high-speed shearing action of the concentric biaxial stirrer before polymerization.

3. The method for synthesizing a water-in-oil polyacrylamide emulsion as described in claim 2, characterized in that, The concentric biaxial stirrer also includes an outer shaft and an inner shaft. The outer shaft wraps around the outside of the inner shaft. The blade-type stirring paddle is located on the outer shaft near the reactor lid. The spiral stirring paddle is located on the outer wall of the outer shaft. The anchor-type stirring paddle is connected to the end of the outer shaft away from the reactor lid. The emulsifying head is located at the end of the concentric biaxial stirrer near the bottom of the reactor.

4. The method for synthesizing a water-in-oil polyacrylamide emulsion as described in claim 3, characterized in that, The emulsifying head includes an outer shaft and an inner shaft; the outer shaft and the inner shaft are nested together, the outer shaft is connected to the end of the outer shaft, and the inner shaft is connected to the end of the inner shaft. The rotational speed difference between the outer shaft and the inner shaft creates a rotational speed difference between them, causing the originally immiscible oil phase and water phase to form a homogeneous water-in-oil emulsion under the action of the emulsifier.

5. The method for synthesizing a water-in-oil polyacrylamide emulsion as described in claim 4, characterized in that, The second stirring motor module includes: An external shaft control motor is provided with a first rotating shaft, and a driving gear is provided at the end of the first rotating shaft. The driving gear meshes with a driven gear provided on the outer wall of the external shaft. An inner shaft control motor is provided, and a second rotating shaft is provided on the inner shaft control motor, the second rotating shaft being connected to the inner shaft.

6. The method for synthesizing a water-in-oil polyacrylamide emulsion as described in claim 5, characterized in that, The outer shaft stirring speed is 200-500 r / min, the inner shaft stirring speed is 1000-2500 r / min, the homogenization time is 7-10 min, and the inner shaft stirring speed is 5-10 times that of the outer shaft stirring speed.

7. The method for synthesizing a water-in-oil polyacrylamide emulsion as described in claim 6, characterized in that, The temperature of the material in the reactor before the initiator is added is set to 10-20°C, the initiator is added for 2 hours, and the polymerization reaction lasts for 4-6 hours.

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