Method for enhancing swelling and dissolution of ionic polymer thickener

Abstract

The invention discloses a method for strengthening swelling and dissolution of an ionic polymer thickening agent, belongs to the field of fluid chaotic mixing, and provides an efficient technology for preparation of the thickening agent. According to the method disclosed by the invention, the rigid and flexible stirring paddles are combined with the variable-diameter stirring tank, the shearing action of the stirring paddles is increased, and an isolation region is eliminated, so that the contact area of the macromolecular thickening agent and an aqueous solution is increased, the water absorption expansion of a macromolecular compound is promoted, 'fisheye 'shapes which are bonded into blocks are effectively eliminated, and the swelling and dissolving time of the thickening agent is shortened. Firstly, a flexible material and a traditional rigid stirring paddle are combined to form a rigid-flexible stirring paddle, water is added into a variable-diameter stirring tank, stirring is started, and a thickening agent is slowly added. The whole process flow is simple, the operation is convenient, and an effective method is provided for dissolving the ionic polymer thickener.

Description

Technical Field

[0001] The invention relates to the field of fluid chaotic mixing, and in particular to a rigid-flexible stirring variable-diameter reactor for strengthening the swelling and dissolution of an ionic polymer thickener. Background Art

[0002] Mixing and stirring play a key role in many industrial processing operations, including metallurgical refining, pharmaceutical production, food processing, chemical manufacturing, etc. At the same time, mixing processes occupy a prominent position in various scientific applications such as biochemical reactions, cell culture and microbiology.

[0003] In the prior art, a central vortex is easily formed in the stirred tank, resulting in a highly circular fluid motion. At high Reynolds numbers, the axial and radial mixing in the stirred tank without baffles is still insufficient. At the same time, the mixing time is usually longer than that in the baffle tank, resulting in lower mixing efficiency. This is because the existing stirred tanks often have arbitrary contour symmetry, which tends to produce symmetrical and periodic flow fields. Even when used with a rigid-flexible combination impeller, the stirring effect is affected. Summary of the invention

[0004] The object of the present invention is to provide a method for strengthening the swelling and dissolution of an ionic polymer thickener, characterized in that:

[0005] The stirring device used comprises a stirring tank (4) and a stirring paddle (3); the horizontal cross section of the inner cavity of the stirring tank (4) for accommodating liquid is elliptical;

[0006] When stirring, the following steps are included:

[0007] 1) injecting low-viscosity liquid into the stirring tank (4);

[0008] 2) turning on the stirring paddle (3) and injecting a high-viscosity liquid into the stirring tank (4);

[0009] 3) After stirring evenly, stop the stirring paddle to obtain a mixed liquid

[0010] Furthermore, the major axis of the ellipse corresponding to the horizontal cross section of the stirring tank (4) is L, and the minor axis is D; D / L=2.

[0011] Furthermore, the stirring paddle (3) is a rigid-flexible combined stirring paddle; the stirring paddle (3) is driven by a motor (1) above its stirring shaft (2).

[0012] Furthermore, the stirring tank (4) is a barrel structure, the upper end of which is open and sealed with a top cover; the top cover is provided with a manhole connected to the inner cavity of the stirring tank (4); the sealing head is provided with a feed inlet; and the bottom of the stirring tank (4) is connected with a discharge port.

[0013] Furthermore, the stirring paddle (3) comprises a plurality of rigid blades (301) and flexible ropes (302) having the same number as the rigid blades (301); the rigid blades are divided into two groups and fixed on the stirring shaft (2); the stirring shaft (2) penetrates the connection center of the rigid blades and radially surrounds the stirring shaft (2); each rigid blade (301) has a circular through hole; each pair of rigid blades (301) is provided with a flexible rope (302); and the two ends of a flexible rope (302) are respectively connected to the rigid blades (301) at the upper and lower ends thereof through a connecting buckle (304).

[0014] Furthermore, the high-viscosity liquid is a polymer thickener, and the low-viscosity liquid is water or an aqueous solution. It is worth noting that water has good fluidity at room temperature and pressure, and its viscosity is relatively low. The addition of a thickener will significantly reduce the fluidity of the fluid and significantly increase the viscosity of the fluid, and the two have a significant viscosity difference. In summary, the viscosity of water itself is very low, and the addition of a thickener can significantly increase the viscosity of the system.

[0015] The technical effects of the present invention are unquestionable:

[0016] A. By utilizing the macroscopic asymmetry of the long axis and short axis of the elliptical groove, the macroscopic flow in the elliptical stirred reactor presents an asymmetric form, thereby improving the swirl flow of the flow field;

[0017] B. The reactor does not require internal components such as baffles and guide tubes; compared with adding baffles and eccentric stirring, it does not increase energy consumption or equipment vibration, saves materials, reduces energy consumption, and is easy to clean. It is an economical and simple mixing intensification method;

[0018] C. In the preferred embodiment, the rigid-flexible combination stirring paddle can be coupled with the elliptical stirring reactor to effectively enhance the swirl flow in the stirring tank; the elliptical stirring tank can overcome the columnar reflux, effectively enhance the axial flow of the fluid, and ultimately achieve swirl flow; the variable diameter feature of the elliptical tank itself destroys the symmetrical structure of the flow field, allowing the flow field of the columnar reflux to be transformed into a swirl flow field. At the same time, the rigid-flexible combination stirring paddle disturbs the mixing isolation zone, causing the size and position of the mixing isolation zone to be continuously adjusted, allowing more fluid to enter the chaos, thereby enhancing the chaotic mixing of the fluid.

[0019] The present invention provides a method for strengthening the swelling and dissolution of an ionic polymer thickener. The method increases the shearing effect of the stirring paddle and eliminates the isolation zone by combining a rigid-flexible stirring paddle with a variable diameter stirring tank, thereby increasing the contact area between the polymer thickener and the aqueous solution, promoting the water absorption and swelling of the polymer compound, and effectively eliminating the "fish-eye" shape of the sticky blocks, thereby shortening the swelling and dissolution time of the thickener. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of a variable diameter stirred reactor;

[0021] Figure 2 It is a schematic diagram of the structure of an elliptical stirred reactor;

[0022] Figure 3 This is a schematic diagram of the experimental device for measuring the performance of an elliptical stirred reactor;

[0023] Figure 4 Acid-base visualization experiment comparing the fading time of the mixing process of double-layer rigid paddle, double-layer steel wire paddle, and double-layer rigid-flexible combination paddle

[0024] Figure 5 Comparison of the effects of a double-layer rigid propeller, a double-layer steel wire propeller, and a double-layer rigid-flexible combination propeller after mixing for ten minutes

[0025] Figure 6 The traditional rigid propeller and the rigid-flexible combination propeller show the proportion of the undissolved part after the mixing effect.

[0026] Figure 7 Chaos Advantages of Elliptical Stirred Tanks

[0027] Figure 8 Comparison of mixing effects between oval and circular grooves

[0028] Fig. 9 It is a stereogram of the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with the embodiments, but it should not be understood that the above subject matter of the present invention is limited to the following embodiments. Without departing from the above technical ideas of the present invention, various substitutions and changes are made according to the common technical knowledge and customary means in the art, which should all be included in the protection scope of the present invention.

[0030] The ionic polymer thickener used in the embodiment of the present invention is anionic polyacrylamide, the stirring paddle is a double-layer rigid-flexible combination stirring paddle, the variable diameter groove is an elliptical stirring groove (4) with a cross-section major axis a=140mm and a minor axis b=70mm, and the stirring speed is 200rpm. The stirring paddle (3) includes six rigid blades (301) and flexible ropes (302) of the same number as (301); the six rigid blades are divided into two groups and fixed on the stirring shaft (2); the stirring shaft (2) penetrates the connection center of the rigid blade and radially surrounds the stirring shaft (2); each rigid blade (301) has a circular through hole; each group of blades (301) is equipped with a flexible rope (302); a flexible rope (302) penetrates the upper and lower groups of blades (301) in turn, and each circular through hole on the rigid blade (301) is connected to the two ends of the flexible rope (302) by a connecting buckle (303).

[0031] Embodiment 1:

[0032] See also Figure 1 and Figure 2 In order to destroy the symmetry and periodicity of the flow field, this embodiment provides a variable diameter stirred reactor for strengthening the swelling and dissolution of an ionic polymer thickener, comprising a stirring tank 4, a head and a stirring device.

[0033] The mixing tank 4 is a barrel structure. The cross section of the mixing tank 4 is elliptical. The upper end of the barrel is open and blocked by a head. The head is provided with a manhole connected to the inner cavity of the mixing tank 4. The head is connected to a feed pipe. The feed pipe extends into the inside of the mixing tank 4. The bottom of the mixing tank 4 is connected to a discharge pipe.

[0034] The stirring device comprises a driving motor 1, a stirring shaft 2 and a stirring paddle 3. The driving motor 1 is arranged above the end cap. The stirring shaft 2 vertically penetrates the end cap. The stirring shaft 2 is driven by the driving motor 1. The stirring shaft 2 is provided with multiple layers of stirring paddles 3. Figure 2 A view of the elliptical stirred reactor structure.

[0035] This embodiment utilizes the macroscopic asymmetry of the long axis and short axis of the elliptical groove, so that the flow field in the elliptical stirred reactor presents an asymmetric shape. Using the asymmetric shape of the stirring tank to destroy the symmetry of the macroscopic flow is undoubtedly a more economical and effective way compared to adding baffles and eccentric stirring. The rigid-flexible combination stirring paddle perturbs the mixing isolation zone, so that the size and position of the mixing isolation zone are constantly adjusted, allowing more fluid to enter the chaos, thereby enhancing the chaotic mixing of the fluid. The rigid-flexible combination stirring paddle can be coupled with the elliptical stirred reactor to effectively enhance the mixing of the fluid in the stirring tank.

[0036] Embodiment 2:

[0037] The main structure of this embodiment is the same as that of embodiment 1, wherein the stirring tank 4 and the end cap are connected by welding.

[0038] Embodiment 3:

[0039] The main structure of this embodiment is the same as that of embodiment 1, wherein, in this embodiment, the stirring reactor is used for efficient mixing reaction of high-viscosity liquids, promoting uniform stirring or sufficient reaction of high-viscosity liquids. The stirring tank 4 is used to contain high-viscosity liquids. The stirring paddle 3 is immersed in the high-viscosity liquid.

[0040] Embodiment 4:

[0041] See also Figure 3This embodiment is used to verify the effectiveness of embodiments 1 to 5. In this embodiment, a pressure sensor is arranged on the stirring tank 4. A camera 6 is arranged outside the stirring tank 4. The torque sensor 5 and the camera 6 are both connected to a computer 7.

[0042] The stirring fluid is a 0.1‰ polyacrylamide solution, and the mixing time of the elliptical stirred reactor is determined by the acid-base neutralization decolorization method. The specific implementation process is to add 1ml of phenolphthalein reagent in the tank and stir it thoroughly to make the phenolphthalein indicator fully and evenly dispersed in the liquid phase. Then add 20ml NaOH solution (concentration is 1mol / L), stir it thoroughly to make the NaOH solution fully dispersed in the liquid phase, because the phenolphthalein indicator turns red when it encounters an alkaline solution, until the tank presents a uniform purple-red color. Adjust the speed of the motor 1, turn on the installed camera 6, and after the speed stabilizes, add 20mL of HCl solution (concentration is 1mol / L) from the top of the stirring tank. At the same time, the camera starts timing and records the color change of the liquid in the tank throughout the process until the purple-red color disappears completely. The torque time series is collected by the torque sensor 5 and transmitted to the computer 7.

[0043] In this embodiment, the experimental conditions are as follows: the rotation speed is 200 rpm, the blade is a three-pitch open turbine blade, and holes with a diameter of 5 mm are opened 20 mm inside the distal end of the blade for connecting the flexible belt. The liquid phase is a 0.1‰ polyacrylamide solution, the color developer is a phenolphthalein reagent, the alkali solution is a 1mol / L NaOH solution, and the acid solution is a 1mol / L HCl solution. No baffle is provided.

[0044] Experimental results: The mixing time was determined by the acid-base neutralization reaction decolorization method. Since the acid-base neutralization reaction is a rapid reaction, the fading time of the phenolphthalein indicator can be considered to be the mixing time. Figure 4 It can be clearly seen that the mixing effect of the rigid-flexible combination impeller is much higher than that of the traditional rigid combination impeller in the same mixing time. Fig. 9 It can be clearly seen that in the mixed liquid with equal height and area, the fading speed in the elliptical groove is significantly faster than that in the circular groove, that is, the mixing effect in the elliptical groove is significantly better than that in the circular groove. The phenomenon shown shows that the asymmetric flow field of the elliptical groove can effectively enhance fluid mixing, shorten mixing time, and improve mixing efficiency.

Claims

1. A method for enhancing the swelling and dissolution of an ionic polymer thickener, characterized in that: The stirring device used comprises a stirring tank (4) and a stirring paddle (3); the horizontal cross-section of the inner cavity of the stirring tank (4) for accommodating liquid is elliptical; When stirring, the following steps are included: 1) First, inject low-viscosity liquid into the stirring tank (4); 2) Then, the stirring paddle (3) is turned on, and a polymer thickener is injected into the stirring tank (4); 3) After stirring evenly, stop the stirring paddle to obtain a mixed liquid.

2. A method for enhancing swelling and dissolution of an ionic polymer thickener according to claim 1, characterized in that: The major axis of the ellipse corresponding to the horizontal cross section of the stirring tank (4) is L, and the minor axis is D; D / L=2.

3. The method for enhancing swelling and dissolution of an ionic polymer thickener according to claim 1, characterized in that: The stirring paddle (3) is a rigid-flexible combined stirring paddle; the stirring paddle (3) is driven by a motor (1) above its stirring shaft (2).

4. The method for enhancing swelling and dissolution of an ionic polymer thickener according to claim 1, characterized in that: The stirring tank (4) is a barrel structure, the upper end of which is open and sealed by a top cover; the top cover is provided with a manhole connected to the inner cavity of the stirring tank (4); the sealing head is provided with a feed inlet; and the bottom of the stirring tank (4) is connected with a discharge outlet.

5. The method for enhancing swelling and dissolution of an ionic polymer thickener according to claim 3, characterized in that: The stirring paddle (3) comprises a plurality of rigid blades (301) and flexible ropes (302) having the same number as the rigid blades (301); the rigid blades are divided into two groups and fixed on the stirring shaft (2); the stirring shaft (2) penetrates the connection center of the rigid blades and radially surrounds the stirring shaft (2); each rigid blade (301) has a circular through hole; each pair of rigid blades (301) is provided with a flexible rope (302); and the two ends of a flexible rope (302) are respectively connected to the rigid blades (301) at the upper and lower ends thereof through a connecting buckle (304).

6. The method for enhancing swelling and dissolution of an ionic polymer thickener according to claim 3, characterized in that: The high-viscosity liquid is a polymer thickener, and the low-viscosity liquid is water or an aqueous solution.

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