Post-treatment method and application of polyolefin drag reducer

Abstract

The invention relates to the technical field of high polymer materials, in particular to a polyolefin drag reducer post-treatment method and application thereof.The polyolefin drag reducer post-treatment method comprises the steps that 1, high-molecular-weight poly-alpha-olefin is produced through a bulk polymerization method, and a polyolefin drag reducer is obtained; step 2, heating, softening and mixing: heating the polyolefin drag reducer to a softened state, partitioning the polyolefin drag reducer to obtain a plurality of blocky polyolefin drag reducers, weighing the coating agent and the blocky polyolefin drag reducers, and mixing the coating agent and the blocky polyolefin drag reducers in an internal mixing device to obtain polyolefin drag reducer blocks; step 3, liquid nitrogen soaking and crushing; and 4, preparing a finished product. According to the preparation work, the polyolefin drag reducer and the coating agent are mixed and then treated in the internal mixing device in a mode similar to rubber mixing, the liquid nitrogen cost is saved, meanwhile, the mixing effect of the polyolefin drag reducer and the coating agent is improved, and the operation risk of operators is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a post-treatment method for a polyolefin drag reducer and application thereof. Background Art

[0002] Drag reducers are additives that can significantly reduce the resistance to fluid flow and are widely used in industrial fields such as oil extraction and transportation. In the process of oil pipeline transportation, drag reducers can effectively reduce the friction resistance between the fluid and the inner wall of the pipeline, improve transportation efficiency, and reduce energy consumption. However, due to its high surface activity, polyolefin drag reducers are prone to adhesion, which not only affects its drag reduction effect, but may also cause pipeline blockage and adversely affect production operations. Therefore, in order to ensure that the drag reducer can fully exert its effectiveness while avoiding potential risks, it is particularly important to post-treat the polyolefin drag reducer.

[0003] Although the traditional post-treatment method of polyolefin drag reducer can improve its surface properties to a certain extent, it has many defects. For example, problems such as poor coating effect and uneven dispersion will not only lead to a decrease in drag reduction efficiency, but also increase the risk of pipeline blockage. In order to solve these problems, the industry usually adopts a method of coating a layer of isolation agent on the surface of polyolefin drag reducer, such as polyethylene wax, to reduce its surface activity. However, the existing coating method is often difficult to achieve the ideal coating effect, the coating layer is easy to fall off, and the coating is uneven, which is difficult to meet the needs of practical applications. In addition, domestic drag reducer products also have the disadvantages of easy stratification during long-term storage, low solid content, and poor slurry stability. These problems limit the application of drag reducers in a wider range of fields, especially in finished oil pipelines. In addition, in the mixing process of polyolefin drag reducer and coating agent used in the prior art, it is necessary to rely on liquid nitrogen to freeze the polyolefin drag reducer, and then coarsely crush it before mixing it with the coating agent. This process increases the cost, and the use of liquid nitrogen also increases the production risk. Therefore, in view of the fact that the liquid nitrogen coarse crushing process still has to be relied on when mixing the polyolefin drag reducer with the coating agent, which increases the production risk, a polyolefin drag reducer post-treatment method is proposed which replaces the use of liquid nitrogen when mixing the polyolefin drag reducer with the coating agent. This method increases the uniform mixing of the polyolefin drag reducer and the coating agent, making the entire process safer. Summary of the invention

[0004] To solve the above problems, the present invention provides a post-treatment method for a polyolefin drag reducer and an application thereof, wherein the polyolefin drag reducer and a coating agent are mixed and post-treated in an internal mixing device in a manner similar to rubber mixing, thereby saving liquid nitrogen costs while improving the mixing effect of the polyolefin drag reducer and the coating agent and reducing the operating risks of operators.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows: A method for post-processing a polyolefin drag reducer comprises the following steps:

[0006] Step 1, preparation: using bulk polymerization to produce high molecular weight poly-alpha-olefin and obtain polyolefin drag reducer;

[0007] Step 2, heating, softening and mixing: heating the polyolefin drag reducer to a softened state and dividing it into blocks to obtain a plurality of block polyolefin drag reducers, weighing the coating agent and the block polyolefin drag reducer for mixing, the mixing is carried out in a mixing device, and the polyolefin drag reducer blocks are obtained;

[0008] Step 3, liquid nitrogen soaking and crushing: cooling the mixed polyolefin drag reducer block and placing it in liquid nitrogen for soaking and crushing to obtain a crushed material, collecting the crushed material, drying it, and then sieving it to obtain a powdered polyolefin drag reducer;

[0009] Step 4, preparing the finished product: adding the obtained powdered polyolefin drag reducer to a suspension medium, a density regulator and an emulsifier to prepare a suspension, thereby obtaining a polyolefin drag reducer slurry for injection into an oil pipeline to exert a drag reduction effect.

[0010] Furthermore, in step 2, the temperature range of heating the polyolefin drag reducer to softening is 60°C to 70°C.

[0011] Furthermore, in step 2, the block division is to cut the polyolefin drag reducer into small blocks with a length not exceeding 15 cm and a thickness not exceeding 2 cm, that is, to obtain a plurality of block-shaped polyolefin drag reducers.

[0012] Furthermore, in step 2, the coating agent is polyethylene wax and calcium stearate, the mass ratio of polyethylene wax to polyolefin drag reducer is 1:3, and the mass ratio of calcium stearate to polyolefin drag reducer is 1:3.

[0013] Furthermore, in step 2, the amount of polyethylene wax added to the coating agent is 20%, and the amount of calcium stearate added is 25%.

[0014] Furthermore, in step three, the polyolefin drag reducer block obtained by mixing is placed in a DC3-1 liquid nitrogen low-temperature pulverizer for fine crushing, and liquid nitrogen is continuously introduced during the fine crushing process.

[0015] Furthermore, in step three, the drying process is performed at 60° C. for 2 hours.

[0016] Furthermore, in step three, the particle size of the powdered polyolefin drag reducer obtained after sieving is 40 to 80 meshes.

[0017] Furthermore, in step 4, the auxiliary agents used to prepare the suspension are: n-hexanol as the main suspension medium, ethylene glycol butyl ether as the density regulator, and polyoxyethylene oleyl alcohol ether as the emulsifier;

[0018] The solid content of the prepared slurry is in the range of 30% to 40%.

[0019] Furthermore, a polyolefin drag reducer prepared based on a polyolefin drag reducer post-treatment method is used to reduce the blockage of a finished oil pipeline pump and to improve the drag reduction rate of a finished oil pipeline.

[0020] The above scheme has the following beneficial effects:

[0021] 1. In this scheme, the polyolefin drag reducer and the coating agent are pre-mixed in a mixing device in a manner similar to rubber mixing, so that the amount of liquid nitrogen required in the subsequent liquid nitrogen immersion and crushing process is reduced, thereby reducing the production cost; the use of the mixing device ensures that the polyolefin drag reducer and the coating agent can be mixed more evenly and fully, improves the dispersibility of the drag reducer in the suspension, and makes it easier to distribute evenly in the oil pipeline.

[0022] 2. In this solution, in the traditional method, the storage, transportation and use of liquid nitrogen pose safety risks. Although this solution still uses liquid nitrogen, it is limited to the crushing step, and the automatic control of the equipment reduces manual operation, thereby reducing safety risks. Compared with the traditional liquid nitrogen mixing method, liquid nitrogen freezing requires pre-cooling, and the internal mixing device has a high degree of automation. It only needs to add the materials to be mixed into the internal mixing device for external operation, which reduces the direct contact of operators and reduces the risk of suffocation caused by low temperature during operation.

[0023] 3. In this scheme, the polyolefin drag reducer after being heated and softened is cut into a plurality of blocks of polyolefin drag reducer and then mixed with the coating agent, thereby increasing the contact area between the polyolefin drag reducer and the coating agent, and making the mixture more uniform.

[0024] 4. In this scheme, the post-treated polyolefin drag reducer powder is easy to be mixed with a suspension medium, a density regulator and an emulsifier to prepare a suspension, which is convenient for subsequent injection and application in the oil pipeline. The prepared polyolefin drag reducer slurry performs well in reducing the blockage of the finished oil pipeline pump and improving the drag reduction rate of the finished oil pipeline, reducing the risk of pipeline blockage caused by agglomeration or precipitation of the drag reducer, and helping to improve the efficiency and safety of pipeline transportation.

[0025] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of the method steps of the polyolefin drag reducer post-treatment method and an application embodiment of the present invention;

[0027] Figure 2 It is a schematic diagram of a post-treatment method of a polyolefin drag reducer of the present invention and an application embodiment thereof;

[0028] Figure 3 It is a schematic diagram of the post-treatment method of the polyolefin drag reducer of the present invention and an application example thereof.

[0029] The figure marks in the drawings of the specification include: 1. internal mixer; 2. transmission rod; 3. reducer; 4. motor; 5. fixed seat; 6. support frame; 7. mixing chamber; 8. discharge pipe; 9. air outlet pipe; 10. adjustment box; 11. air inlet pipe; 12. feed pipe; 13. driving rotor; 14. driven rotor. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only 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.

[0031] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0032] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] The following is further described in detail through specific implementation methods:

[0034] Embodiment 1:

[0035] As attached Figure 1 As shown: A post-treatment method for a polyolefin drag reducer comprises the following steps:

[0036] Step 1, preparation: using bulk polymerization to produce high molecular weight poly-alpha-olefin and obtain polyolefin drag reducer.

[0037] Step 2, heating, softening and mixing: the polyolefin drag reducer is heated to 60°C to 70°C to obtain its softened state, and is divided into blocks, wherein the polyolefin drag reducer is cut into small blocks with a length not exceeding 15 cm and a thickness not exceeding 2 cm, that is, a plurality of block polyolefin drag reducers are obtained, and a coating agent is weighed and mixed with the block polyolefin drag reducer. The coating agent is polyethylene wax and calcium stearate, and the mass ratio of polyethylene wax to polyolefin drag reducer is 1:3, and the mass ratio of calcium stearate to polyolefin drag reducer is 1:3. The amount of polyethylene wax added to the coating agent is 20%, and the amount of calcium stearate added to the coating agent is 25%. The mixing is carried out in a mixing device to obtain a polyolefin drag reducer block.

[0038] Step three, liquid nitrogen soaking and crushing: After the mixed polyolefin drag reducer block is cooled, it is placed in a DC3-1 liquid nitrogen low-temperature crusher for fine crushing to obtain a crushed material, and liquid nitrogen is continuously introduced during the fine crushing process. The crushed material is collected and dried at 60°C for 2 hours and then sieved. The powdered polyolefin drag reducer obtained after sieving has a particle size of 40 to 80 meshes, that is, a powdered polyolefin drag reducer is obtained.

[0039] Step 4, preparing the finished product: adding n-hexanol as the main suspension medium, ethylene glycol butyl ether as the density regulator, and polyoxyethylene oleyl alcohol ether as the emulsifier to the obtained powdered polyolefin drag reducer, the powdered polyolefin drag reducer and the suspension medium, density regulator and emulsifier are prepared into a suspension, and the solid content of the prepared slurry is in the range of 30% to 40%, so as to obtain a polyolefin drag reducer slurry for injection into an oil pipeline to exert a drag reduction effect.

[0040] The invention discloses an application of a polyolefin drag reducer prepared by a polyolefin drag reducer post-treatment method in reducing the blockage of a pipe pump in a refined oil pipeline and improving the drag reduction rate of a refined oil pipeline.

[0041] Embodiment 2:

[0042] As attached Figure 2 and Figure 3 As shown, the difference from Example 1 is that, in step 2, the internal mixing device includes an internal mixer 1, a support frame 6 is fixedly connected to the lower part of the internal mixer 1, a mixing chamber 7 is provided in the internal mixer 1, a rotor assembly is provided in the mixing chamber 7, a feed pipe 12 and a discharge pipe 8 are respectively connected to the top and bottom of the mixing chamber 7, an air filter is provided at the connection between the mixing chamber 7 and the feed pipe 12 and the discharge pipe 8, a valve is fixedly connected to the side of the feed pipe 12 and the discharge pipe 8 away from the mixing chamber 7, a drive assembly is provided on one side of the internal mixer 1, and one end of the drive assembly extends into the mixing chamber 7 and is fixedly connected to the rotor assembly.

[0043] The driving assembly includes a motor 4 and a fixed seat 5, the fixed seat 5 is located on one side of the support frame 6, the motor 4 is fixedly connected to the top of the fixed seat 5, the motor 4 signal is connected to the controller, the output shaft of the motor 4 is coaxially fixedly connected to the transmission rod 2, the transmission rod 2 is sleeved with a reducer 3, the reducer 3 is connected to the controller signal, the bottom of the reducer 3 is fixedly connected to the top of the fixed seat 5, and the transmission rod 2 extends to the mixing chamber 7 at one end away from the motor 4 and the reducer 3.

[0044] The rotor assembly includes an active rotor 13 and a driven rotor 14. The arc-shaped protrusions at both ends of the active rotor 13 and the driven rotor 14 are wedged with the inner wall of the mixing chamber 7, and the arc-shaped protrusions at both ends of the active rotor 13 and the driven rotor 14 are wedged with the arc-shaped concave parts on both sides of the active rotor 13 and the driven rotor 14. The transmission rod 2 is coaxially fixedly connected with the active rotor 13. One side of the feed pipe 12 is connected with an air inlet pipe 11, and one side of the discharge pipe 8 is connected with an air outlet pipe 9. The end of the air inlet pipe 11 away from the feed pipe 12 is connected with an adjustment box 10, and the air outlet pipe 9 is connected with the end of the adjustment box 10 away from the air inlet pipe 11. An air pump is arranged in the adjustment box 10, and the air pump is respectively connected to the air inlet pipe 11 and the air outlet pipe 9. The outer wall of the mixing chamber 7 is fixedly connected with a temperature sensor, and the inner wall of the mixing chamber 7 is provided with a heating wire. The air pump, the temperature sensor and the heating wire are all connected with the controller signal.

[0045] The specific implementation process is as follows: the valve at one end of the feed pipe 12 is opened by the controller, a number of blocky polyolefin drag reducers are fed into the mixing chamber 7 from the feed pipe 12, and then the coating agent is added, the valve is closed, the motor 4 and the electric heating wire are started, and the active rotor 13 and the driven rotor 14 rotate in opposite directions under the drive of the motor 4. After the active rotor 13 rotates through the feed pipe 12, the arc-shaped protrusion of the driven rotor 14 is wedged with the arc-shaped concave part of the active rotor 13, and the arc-shaped protrusion of the active rotor 13 is wedged with the inner wall of the mixing chamber 7. At this time, the active rotor 13 and the driven rotor 14 are wedged with each other. A sealed chamber is formed between the rotor 14 and the inner wall of the mixing chamber 7. At this time, the block polyolefin drag reducer and the coating agent are clamped by the two rotors and brought into the roller gap. The block polyolefin drag reducer and the coating agent are squeezed and sheared by the rotors. This process increases the rotation area in the mixing chamber 7, so that the block polyolefin drag reducer and the coating agent can be more evenly mixed in the mixing chamber 7; at this time, the rotor continues to rotate, and the material is sheared and rubbed, so that the temperature of the block polyolefin drag reducer increases and the viscosity decreases, so that the coating agent can fully contact with the surface of the polyolefin drag reducer.

[0046] Since the mixing chamber 7 itself will provide heat through the electric heating wire, and new heat will be generated during the shearing and extrusion process, in this process, the gas extracted from the inlet of the air pump will enter the mixing chamber 7 through the air inlet pipe 11, and when the rotor rotates, the two rotors and the inner wall of the mixing chamber 7 form a sealed chamber, and then as the rotor continues to rotate, the air in the sealed chamber is pressed into the air outlet pipe 9, and the temperature sensor senses whether the temperature in the mixing chamber 7 is too high. If the temperature is normal, the air pump only connects the air inlet pipe 11 and the air outlet pipe 9, so that the air The air repeatedly passes through the air inlet pipe 11 and the air outlet pipe 9, so that the heat can circulate in the air inlet pipe 11 and the air outlet pipe 9, and when the hot air circulates through the air inlet pipe 11 and the air outlet pipe 9, it will also exchange heat with the outside world, taking away part of the heat, so that the temperature in the mixing chamber 7 will not be overheated immediately; and when the heat exchange with the outside world cannot take away the excess heat, the temperature controller transmits this temperature signal to the controller, and the controller controls the air pump to discharge the hot air in the air outlet pipe 9, and then inhale it from the outside air to take away the excess heat generated during mixing.

[0047] Embodiment 3:

[0048] The difference from Example 2 is that the polyolefin drag reducer rubber mixing and coating effect experiment is as follows:

[0049] 1. Experimental Subjects

[0050] Experimental group A: The polyolefin drag reducer block prepared in step 2 of the method was crushed into particles of 0.5 cm;

[0051] Experimental group B: The polyolefin drag reducer prepared in step 1 of the method was frozen in liquid nitrogen for 20 minutes, and the frozen polymer was put into a BP-180 crusher for coarse crushing to obtain coarse drag reducer particles with a particle size of about 0.5 cm and mixed evenly with the coating agent used in step 2;

[0052] Control group: Take the polyolefin drag reducer and crush it into 0.5 cm particles at room temperature, and mix it evenly with the coating agent used in step 2.

[0053] 2. Experimental process

[0054] The microstructure of the drag reducer particles is observed by scanning electron microscopy (SEM) or transmission electron microscopy (TEM), and the distribution of the coating agent and the coating effect are evaluated based on the coating adhesion.

[0055] 3. Experimental Results

[0056] Table 1 Effect of different treatment methods on coating effect

[0057] Group Experimental Group A Experimental Group B Control group Wrapping effect Basically no bonding Basically no bonding Completely bonded together

[0058] Conclusion: The drag reducing polymer is an ultra-high molecular weight polymer with side chains, and the interaction between molecules is strong. Therefore, the polymer is in a viscoelastic state at room temperature. When the polyolefin drag reducer is mixed with the coating agent at room temperature, the coating has almost no effect due to the strong interaction between the molecules. However, the coating effect of the polyolefin drag reducer by the method used in the present invention (experimental group A) and after liquid nitrogen crushing (experimental group B) is that the polyolefin drag reducer basically does not stick together after heating. Therefore, the post-treatment method similar to rubber mixing used in the present invention to mix the polyolefin drag reducer and the coating agent can achieve the same effect as traditional liquid nitrogen, while also reducing the risk of human operation.

[0059] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A post-treatment method for a polyolefin drag reducer, characterized in that: The following steps are involved: Step 1, preparation: using bulk polymerization to produce high molecular weight poly-alpha-olefin and obtain polyolefin drag reducer; Step 2, heating, softening and mixing: heating the polyolefin drag reducer to a softened state and dividing it into blocks to obtain a plurality of block polyolefin drag reducers, weighing the coating agent and the block polyolefin drag reducer for mixing, the mixing is carried out in a mixing device, and the polyolefin drag reducer blocks are obtained; Step 3, liquid nitrogen soaking and crushing: cooling the mixed polyolefin drag reducer block and placing it in liquid nitrogen for soaking and crushing to obtain a crushed material, collecting the crushed material, drying it, and then sieving it to obtain a powdered polyolefin drag reducer; Step 4, preparing the finished product: adding the obtained powdered polyolefin drag reducer to a suspension medium, a density regulator and an emulsifier to prepare a suspension, thereby obtaining a polyolefin drag reducer slurry for injection into an oil pipeline to exert a drag reduction effect.

2. The post-treatment method of polyolefin drag reducer according to claim 1, characterized in that: In step 2, the polyolefin drag reducer is heated to a softening temperature in the range of 60°C to 70°C.

3. The post-treatment method of polyolefin drag reducer according to claim 2, characterized in that: In step 2, the block division is to cut the polyolefin drag reducer into blocks with a length not exceeding 15 cm and a thickness not exceeding 2 cm, that is, to obtain a plurality of blocks of polyolefin drag reducer.

4. The post-treatment method of polyolefin drag reducer according to claim 3, characterized in that: In step 2, the coating agent is polyethylene wax and calcium stearate, the mass ratio of polyethylene wax to polyolefin drag reducer is 1:3, and the mass ratio of calcium stearate to polyolefin drag reducer is 1:

3.

5. The post-treatment method of polyolefin drag reducer according to claim 4, characterized in that: In step 2, the amount of polyethylene wax added to the coating agent is 20%, and the amount of calcium stearate added is 25%.

6. The post-treatment method of polyolefin drag reducer according to claim 5, characterized in that: In step three, the polyolefin drag reducer block obtained by mixing is placed in a DC3-1 liquid nitrogen low-temperature pulverizer for fine crushing, and liquid nitrogen is continuously introduced during the fine crushing process.

7. The post-treatment method of polyolefin drag reducer according to claim 6, characterized in that: In step 3, the drying process is performed at 60° C. for 2 h.

8. The post-treatment method of polyolefin drag reducer according to claim 7, characterized in that: In step 3, the particle size of the powdered polyolefin drag reducer obtained after sieving is 40 to 80 meshes.

9. The post-treatment method of polyolefin drag reducer according to claim 8, characterized in that: In step 4, the auxiliary agents used to prepare the suspension are: n-hexanol as the main suspension medium, ethylene glycol butyl ether as the density regulator, and polyoxyethylene oleyl alcohol ether as the emulsifier; The solid content of the prepared slurry is in the range of 30% to 40%.

10. Use of the polyolefin drag reducer prepared by the method according to any one of claims 1 to 9 in reducing blockage of pipe pumps in a refined oil pipeline and improving the drag reduction rate of a refined oil pipeline.

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