A system and method for preparing a crude oil paraffin inhibitor and pour point depressant

Abstract

The application belongs to the technical field of petroleum chemical industry, and particularly discloses a system and method for preparing a crude oil paraffin inhibitor and pour point depressant, which comprises a vertical reaction kettle, a homogenizer, a mixing barrel, a standing tank, an ultrasonic cleaner and a blast drying oven, the standing tank is provided with a filter assembly composed of a polypropylene non-woven fabric layer, a glass fiber layer and a polytetrafluoroethylene microporous membrane layer, waste heat gas of the blast drying oven is introduced into a reaction kettle jacket through an exhaust pipe to assist preheating, and each component is communicated and controlled by a PLC controller and a central control platform. In the method, specific proportioned monomer A, monomer B and a surfactant are prepared into a pre-emulsion liquid by the homogenizer, an initiator aqueous solution is prepared by ultrasonic, and the pre-emulsion liquid and the initiator aqueous solution are injected into the reaction kettle in stages according to a proportion to react and cool, and then the product is obtained through standing, filtering and drying. The application has high automation degree, reasonable energy utilization and stable performance of the prepared paraffin inhibitor and pour point depressant.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of petroleum chemical industry, and particularly relates to a system and method for preparing a paraffin inhibitor and pour point depressant for crude oil. BACKGROUND

[0002] The paraffin inhibitor and pour point depressant, also known as a low-temperature flow improver (PPD), is a kind of chemical additive used to improve the low-temperature fluidity of high-wax-content crude oil. Its core function is to change the morphology and size of wax crystals through a physical method, rather than a chemical reaction with the crude oil. When the temperature of the crude oil decreases, the wax dissolved in the crude oil will crystallize and gradually form a three-dimensional network structure, resulting in a sharp increase in the viscosity of the crude oil and an increase in the freezing point, thus losing fluidity. The pour point depressant inhibits the aggregation of wax crystals and the formation of network structures by adsorbing on the surface of the wax crystals or co-crystallizing, so that the wax crystals exist in a dispersed and fine form, thereby reducing the freezing point and apparent viscosity of the crude oil and enhancing its flow performance. However, the pour point depressant cannot prevent the precipitation of wax crystals itself, but only modifies the growth behavior of the wax crystals, so its effect depends on the composition of the crude oil and the operating conditions.

[0003] The crude oil resources in China are mainly high-wax-content crude oil, with a wax content generally as high as 15%-37%, and the wax content of the crude oil in individual oilfields even exceeds 40%. The crude oil of an oilfield company has a relatively low wax content, generally 2.5%-10%, but there is still a risk of wax deposition. During the transportation of the crude oil, when the oil temperature drops below the critical point, a large amount of wax precipitates, resulting in wax deposition on the inner wall of the pipeline, a decrease in the oil transportation capacity, and in severe cases, causing blockage accidents and threatening the safe operation of the pipeline. Traditionally, China mainly uses the heating transportation process to alleviate this problem, but this method has significant defects: large fuel consumption, high operating cost, narrow transportation capacity adjustment range, and limited pipeline shutdown time, otherwise the "frozen pipe" accident is likely to occur. In contrast, adding a paraffin inhibitor and pour point depressant is an efficient and economical alternative solution, which has the advantages of simple operation, environmental protection and energy saving, less equipment investment, etc., and can significantly improve the safety and flexibility of pipeline operation, thus attracting widespread attention from the domestic and foreign petroleum industry.

[0004] Although the technology of wax inhibitor and pour point depressant has developed for decades, the existing agents still have the following limitations: ① Insufficient adaptability: the effect of pour point depressant is highly dependent on the chemical composition of crude oil such as wax content and carbon number distribution. The existing agents are often designed for specific oil products, and have poor universality. For example, the sensitivity of common pour point depressants such as polymethyl acrylate and EVA modifiers to crude oil from different regions varies significantly, and needs to be adjusted by compounding or modification, increasing the complexity of application. ② Functional limitations: pour point depressant can only change the morphology of wax crystals and cannot inhibit the precipitation process of wax. In extreme low temperature or high wax conditions, the network structure of wax crystals may still form, resulting in unstable pour point depression effect. In addition, the cleaning ability of pour point depressant for the formed wax layer is limited, and the wax prevention effect is mostly preventive, which is difficult to solve the existing plugging problem. Although nitrogen-containing polymer pour point depressant has good stability, the synthesis process is complex and the cost is high. ④ High demand for compounding and modification: in order to expand the application range, pour point depressant often needs to be copolymerized, grafted or compounded, but this may lead to poor compatibility of the agent, increased addition amount, and thus increased cost and secondary pollution risk. The root cause of these problems is that the mechanism of physical modification of wax crystals has inherent limitations, which makes it difficult to balance the universality, stability and economy of the agent, and cannot systematically meet the wax prevention and pour point depression needs of high-wax crude oil under different transportation conditions. SUMMARY

[0005] The purpose of the present application is to provide a system and method for preparing a crude oil wax inhibitor and pour point depressant, to solve the problem that the existing technology based on the mechanism of physical modification of wax crystals has inherent limitations, which makes it difficult to balance the universality, stability and economy of the agent, and cannot systematically meet the wax prevention and pour point depression needs of high-wax crude oil under different transportation conditions.

[0006] To achieve the above-mentioned purpose, the basic scheme provided by the present application is: a system for preparing a crude oil wax inhibitor and pour point depressant, comprising a vertical reaction kettle, a homogenizer, a mixing barrel, a standing tank, an ultrasonic cleaner and a forced air drying oven. The homogenizer is connected to the mixing barrel. The mixing barrel is connected to a liquid outlet pipe one. The liquid outlet pipe one is provided with a liquid outlet valve one. The liquid outlet pipe one is connected to the vertical reaction kettle. The ultrasonic cleaner is connected to a liquid outlet pipe two. The liquid outlet pipe two is provided with a liquid outlet valve two. The vertical reaction kettle is provided with a liquid injection tank. The liquid outlet pipe two is connected to the liquid injection tank. The liquid injection tank is connected to a liquid outlet pipe three. The liquid outlet pipe three is provided with a liquid outlet valve three. The liquid outlet pipe three is connected to the vertical reaction kettle. The bottom of the vertical reaction kettle is provided with a liquid outlet pipe four. The liquid outlet pipe four is provided with a liquid outlet valve four. The liquid outlet pipe four is connected to the standing tank. The standing tank is provided with a detachable filter assembly. The bottom end of the standing tank is provided with a liquid discharge pipe. The liquid discharge pipe is provided with a liquid discharge valve. The sidewall of the standing tank is connected to a liquid suction pipe. The liquid suction pipe is provided with a liquid suction valve. The liquid suction pipe is connected to a liquid suction pump. The standing tank is provided with a liquid level sensor. The liquid level sensor is electrically connected to the liquid suction valve. The liquid suction pipe is connected to the forced air drying oven.

[0007] The working principle of the present application is that: the homogenizer and the mixing barrel are used for mixing and homogenizing the initial raw materials, the slurry is transported to the vertical reaction kettle through the liquid outlet pipe, and the cleaning liquid or specific components provided by the ultrasonic cleaner can be accurately added into the reaction kettle through the liquid injection tank to carry out the core synthesis reaction; after the reaction is completed, the product is discharged into the standing tank through the liquid outlet pipe four, and the filter assembly in the standing tank can separate the solid-liquid mixture; the liquid level sensor in the standing tank monitors the liquid level, and when the set value is reached, the liquid pumping valve and the liquid pumping pump are automatically controlled to start, so that the upper layer of the coarse emulsion is pumped out and transported to the air drying oven for final drying, so that the finished product of the paraffin inhibitor is obtained.

[0008] The present application has the advantages that: the system integrates multiple functional units such as homogenization, reaction, cleaning, standing separation and drying, and builds a closely connected and continuously efficient automatic production line. The advantages are that: the ultrasonic cleaner removes impurities in the reaction components through ultrasonic cavitation, ensuring the mixing degree and cleanliness of the mixed liquid; the detachable filter assembly in the standing tank and the automatic liquid pumping system linked by the liquid level sensor greatly optimize the solid-liquid separation efficiency and reduce manual intervention and product loss; the overall system design is compact and reasonable, which not only improves the production efficiency and product purity, but also enhances the controllability and stability of the production process.

[0009] Scheme two, which is a preferred embodiment of the basic scheme, the filter assembly includes a frame and a composite filter membrane, the composite filter membrane is nested in the frame, and the composite filter membrane is composed of a polypropylene non-woven fabric layer, a glass fiber layer and a polytetrafluoroethylene microporous membrane layer. The composite filter membrane realizes gradient filtration and surface interception through the synergistic effect of the three layers of materials, thereby significantly improving the filtration precision, efficiency and overall durability of the assembly.

[0010] Scheme three, which is a preferred embodiment of the basic scheme, the vertical reaction kettle is provided with a jacket, the air outlet of the air drying oven is provided with a wind collecting hood, the wind collecting hood is communicated with an exhaust pipe, and the exhaust pipe is communicated with the jacket. This design can efficiently recover the waste heat discharged from the air drying oven for preheating the vertical reaction kettle, thereby significantly reducing the overall energy consumption of the system and improving the energy utilization rate.

[0011] Scheme four, which is a preferred embodiment of scheme three, the jacket is provided with a condensate discharge pipe at the bottom, and the condensate discharge pipe is provided with a condensate discharge valve. This structure can timely discharge the condensate in the jacket, effectively maintain the heat exchange efficiency of the jacket, ensure the temperature stability in the reaction kettle, thereby improving the process effect and saving energy.

[0012] Scheme five, which is the preferred embodiment of the base scheme, the outlet valve one, the outlet valve two, the outlet valve three, the outlet valve four, the liquid discharge valve, the liquid suction valve, the liquid suction pump, the homogenizer, the vertical reaction kettle, the liquid level sensor are electrically connected with the PLC controller, and the PLC controller is in communication connection with the central control platform. Through the integration of the PLC controller and the central control platform, centralized automatic control and remote real-time monitoring of the entire production process are realized, greatly improving the operation precision, production efficiency and system reliability.

[0013] Scheme six, a method for preparing a crude oil anti-wax and pour point depressant, comprising the following steps:

[0014] S1: add the acrylic ester monomer A with long chain alkyl to the mixing barrel in sequence: 10%-12%, the olefin functional monomer B containing carboxyl, anhydride group, amide group or ester group: 2.5%-3%, non-ionic surfactant: 0.3%-0.6%, deionized water: 84.4%-87.2%, mix by using the homogenizer, set the homogenizer speed to 3000 rpm, the stirring time is 10-13 min, after stirring and mixing, the pre-emulsion is obtained;

[0015] S2: add the initiator and deionized water into the ultrasonic cleaner in a ratio of 1:91 and ultrasonic for 30-35 min to obtain the initiator aqueous solution;

[0016] S3: the operator controls remotely through the central control platform, adds 20% pre-emulsion into the vertical reaction kettle, and adds 20% initiator aqueous solution into the liquid injection tank, controls the heating element in the vertical reaction kettle to heat the temperature to 80±1℃, and the stirring motor speed is 150 rpm;

[0017] S4: after reaching the set temperature, the operator adds the initiator aqueous solution in the liquid injection tank into the vertical reaction kettle, the injection rate is controlled at 0.13-0.14 kg / min, and the injection time is set to 30-35 min, and the pre-emulsion and the initiator aqueous solution are preliminarily mixed in a ratio of 35:2-35:3;

[0018] S5: after preliminary mixing, add the remaining 80% pre-emulsion into the vertical reaction kettle, and add the remaining 80% initiator aqueous solution into the liquid injection tank, set the injection rate of the pre-emulsion to 1.5-1.6 kg / min, and the injection rate of the initiator aqueous solution to 0.09-0.1 kg / min, and inject synchronously, after the injection is completed, continue to stir for 2-2.5 h;

[0019] S6: after sufficient stirring, the pre-emulsion and the initiator aqueous solution react to form a polymer product solution, which is naturally cooled to room temperature;

[0020] S7: The operator opens the liquid outlet valve four, and the cooled polymer product solution is discharged into the standing tank, and is allowed to stand for 24 hours for separation and filtration to obtain a polymer crude emulsion;

[0021] S8: The polymer crude emulsion is pumped into a forced air drying oven, the air temperature in the forced air drying oven is controlled at 60-63 DEG C, and the polymer crude emulsion is dried for 12-18 hours to form a paraffin inhibitor and pour point depressant, and the waste heat generated in the drying process is introduced into the jacket of the vertical reaction kettle in step S3 to assist preheating.

[0022] Working principle: The method prepares the paraffin inhibitor and pour point depressant through a step-by-step and controllable feeding and reaction process. The monomers, surfactants and the like are uniformly grinded at high speed in a mixing barrel to form a stable pre-emulsion. Meanwhile, an initiator solution is prepared under the action of ultrasonic waves. In a vertical reaction kettle, a "preheating of bottom material-synchronous batchwise dropping" polymerization process is adopted. A small amount of pre-emulsion and initiator solution are first added for preliminary reaction, and then the remaining materials are synchronously dropped at a precisely controlled rate. The copolymerization reaction is completed under constant temperature stirring to generate a polymer product. After the reaction, the solution is allowed to stand for separation and filtration to obtain a crude emulsion, and finally the crude emulsion is dried into the final product in a forced air drying oven at a specific temperature.

[0023] Advantages: The application uses long-chain alkyl-containing acrylate and polar group-containing olefin monomers to embed wax crystal structure and change wax crystal growth habit during polymerization, thereby significantly improving the universality and performance stability of the paraffin inhibitor and pour point depressant. The preparation system realizes precise and automatic control of temperature, feeding rate and reaction time through PLC and a central control platform, and combines ultrasonic dispersion and gradient temperature polymerization process to significantly improve the monomer conversion rate and the molecular weight distribution uniformity of the polymer product, thereby guaranteeing excellent and stable performance of the paraffin inhibitor and pour point depressant. Meanwhile, the waste heat generated in the drying process is innovatively recycled for preheating of the reaction kettle, thereby constructing an efficient internal energy circulation, reducing overall energy consumption, further optimizing temperature stability of the reaction process, and achieving economic benefits and environmental protection value.

[0024] Scheme seven, which is a preferred embodiment of scheme six, in step S1, the monomer A is selected from at least one of hexadecyl acrylate, octadecyl acrylate and docosyl acrylate.

[0025] Scheme eight, which is a preferred embodiment of scheme six, in step S1, the monomer B is selected from at least one of acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, acrylamide, methacrylamide, vinyl acetate, methyl acrylate, hydroxyethyl acrylate and hydroxypropyl acrylate.

[0026] In Scheme IX, which is a preferred version of Scheme VI, in step S2, the initiator is a water-soluble radical initiator, and the water-soluble radical initiator is at least one selected from the group consisting of ammonium persulfate, potassium persulfate and sodium persulfate.

[0027] In Scheme X, which is a preferred version of Scheme VI, in step S8, the waste heat gas entering the jacket preliminarily preheats the vertical reaction kettle, and the heating power of the heating element is controlled according to the real-time temperature after preheating. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a structural schematic diagram of a system and method for preparing a crude oil wax inhibitor and pour point depressant according to the present application;

[0029] Figure 2 is a top view of a standing tank in the system and method for preparing a crude oil wax inhibitor and pour point depressant according to the present application;

[0030] Figure 3 is a top view of a standing tank in the system and method for preparing a crude oil wax inhibitor and pour point depressant according to the present application; Figure 2 is a sectional view of A-A in

[0031] Figure 4 is a top view of a vertical reaction kettle in the system and method for preparing a crude oil wax inhibitor and pour point depressant according to the present application;

[0032] Figure 5 is a sectional view of B-B in Figure 4

[0033] Figure 6 is a structural schematic diagram of a vertical reaction kettle and a forced air drying oven in the system and method for preparing a crude oil wax inhibitor and pour point depressant according to the present application;

[0034] Figure 7 is an IR graph of a crude oil wax inhibitor and pour point depressant produced in a laboratory and pilot production of the system and method for preparing a crude oil wax inhibitor and pour point depressant according to the present application;

[0035] Figure 8 is a 1H NMR graph of a crude oil wax inhibitor and pour point depressant produced in a laboratory of the system and method for preparing a crude oil wax inhibitor and pour point depressant according to the present application;

[0036] Figure 9 is a 1H NMR graph of a crude oil wax inhibitor and pour point depressant produced in a pilot production of the system and method for preparing a crude oil wax inhibitor and pour point depressant according to the present application. DETAILED DESCRIPTION

[0037] The present application will be further described in detail through specific embodiments:

[0038] ​The reference numerals in the attached drawings of the specification include: 1. Vertical reaction kettle, 2. Homogenizer, 3. Mixing barrel, 4. Standing tank, 5. Ultrasonic cleaner, 6. Air blast drying oven, 7. Liquid outlet pipe 1, 8. Liquid outlet valve 1, 9. Liquid outlet pipe 2, 10. Liquid outlet valve 2, 11. Liquid injection tank, 12. Liquid outlet pipe 3, 13. Liquid outlet valve 3, 14. Liquid outlet pipe 4, 15. Liquid outlet valve 4, 16. Liquid discharge pipe, 17. Liquid discharge valve, 18. Liquid suction pipe, 19. Liquid suction valve, 20. Liquid suction pump, 21. Liquid level sensor, 22. Frame, 23. Composite filter membrane, 2301. Polypropylene non-woven fabric layer, 2302. Glass fiber layer, 2303. Polytetrafluoroethylene microporous membrane layer, 24. Jacket, 25. Air collecting hood, 26. Exhaust pipe, 27. Condensate discharge pipe, 28. Condensate discharge valve.

[0039] Example 1

[0040] As Figures 1 to 6The system for preparing crude oil anti-wax and pour point depressant is shown, which comprises a vertical reaction kettle 1, a homogenizer 2, a mixing barrel 3, a standing tank 4, an ultrasonic cleaner 5 and a blowing drying box 6, the homogenizer 2 is connected with the mixing barrel 3, the mixing barrel 3 is communicated with a liquid outlet pipe one 7, the liquid outlet pipe one 7 is provided with a liquid outlet valve one 8, the liquid outlet pipe one 7 is communicated with the vertical reaction kettle 1, the ultrasonic cleaner 5 is communicated with a liquid outlet pipe two 9, the liquid outlet pipe two 9 is provided with a liquid outlet valve two 10, the vertical reaction kettle 1 is provided with a liquid injection tank 11, the liquid outlet pipe two 9 is communicated with the liquid injection tank 11, the liquid injection tank 11 is communicated with a liquid outlet pipe three 12, the liquid outlet pipe three 12 is provided with a liquid outlet valve three 13, the liquid outlet pipe three 12 is communicated with the vertical reaction kettle 1, the bottom of the vertical reaction kettle 1 is provided with a liquid outlet pipe four 14, the liquid outlet pipe four 14 is provided with a liquid outlet valve four 15, the liquid outlet pipe four 14 is communicated with the standing tank 4, the standing tank 4 is provided with a detachable filter assembly, the filter assembly comprises a frame 22 and a composite filter membrane 23, the composite filter membrane 23 is nested in the frame 22, the composite filter membrane 23 is composed of a polypropylene non-woven fabric layer 2301, a glass fiber layer 2302 and a polytetrafluoroethylene microporous membrane layer 2303, the bottom end of the standing tank 4 is provided with a liquid discharge pipe 16, the liquid discharge pipe 16 is provided with a liquid discharge valve 17, the sidewall of the standing tank 4 is communicated with a liquid pumping pipe 18, the liquid pumping pipe 18 is provided with a liquid pumping valve 19, the liquid pumping pipe 18 is communicated with a liquid pumping pump 20, the standing tank 4 is provided with a liquid level sensor 21, the liquid level sensor 21 is electrically connected with the liquid pumping valve 19, the liquid pumping pipe 18 is communicated with the blowing drying box 6, the outer wall of the vertical reaction kettle 1 is provided with a jacket 24, the air outlet of the blowing drying box 6 is provided with a wind collecting hood 25, the wind collecting hood 25 is communicated with an exhaust pipe 26, the exhaust pipe 26 is communicated with the jacket 24, the bottom of the jacket 24 is provided with a condensate water discharge pipe 27, the condensate water discharge pipe 27 is provided with a condensate water discharge valve 28, the liquid outlet valve one 8, the liquid outlet valve two 10, the liquid outlet valve three 13, the liquid outlet valve four 15, the liquid discharge valve 17, the liquid pumping valve 19, the liquid pumping pump 20, the homogenizer 2, the vertical reaction kettle 1 and the liquid level sensor 21 are electrically connected with a PLC controller, and the PLC controller is in communication connection with a central control platform.

[0041] The embodiment of the present application is:

[0042] When using the system, the material is first processed by the homogenizer 2 and then delivered to the mixing bucket 3. The operator controls the PLC controller through the central control platform to open the liquid outlet valve one 8 to make the material in the mixing bucket 3 enter the vertical reaction kettle 1 through the liquid outlet pipe one 7. At the same time, the ultrasonic cleaner 5 is started, and then the liquid outlet valve two 10 is opened to send the material in the ultrasonic cleaner 5 into the liquid injection tank 11 through the liquid outlet pipe two 9, and then the liquid outlet valve three 13 is opened to make the material in the liquid injection tank 11 enter the vertical reaction kettle 1 through the liquid outlet pipe three 12, and then the vertical reaction kettle 1 is reacted. After the reaction is completed, the liquid outlet valve four 15 is opened, and the material enters the standing tank 4 through the liquid outlet pipe four 14. During the standing process, it is filtered through the composite filter membrane 23 composed of the polypropylene non-woven fabric layer 2301, the glass fiber layer 2302 and the polytetrafluoroethylene microporous membrane layer 2303 in the frame 22. After standing, part of the liquid is discharged through the liquid discharge pipe 16 by opening the liquid discharge valve 17. When the liquid level sensor 21 detects that the liquid level in the standing tank 4 reaches the set value, the liquid pumping valve 19 is automatically opened and the liquid pumping pump 20 is started to send the material into the air drying oven 6 for drying through the liquid pumping pipe 18. The hot air of the air drying oven 6 is sent to the jacket 24 of the outer wall of the vertical reaction kettle 1 through the air collecting hood 25 and the air exhaust pipe 26 for heat preservation. The condensate in the jacket 24 is discharged through the condensate discharge pipe 27 and the condensate discharge valve 28.

[0043] Example two

[0044] As shown in Figures 1 to 9 A method for preparing a crude oil anti-waxing and de-waxing agent, comprising the following steps:

[0045] S1: adding the acrylic ester monomer A with long-chain alkyl group: 10%-12%, the olefin functional monomer B containing carboxyl, anhydride group, amide group or ester group: 2.5%-3%, surfactant: 0.3%-0.6%, and deionized water: 84.4%-87.2% into the mixing bucket 3 in sequence, stirring and mixing by using the homogenizer 2, setting the rotation speed of the homogenizer 2 to 3000 rpm, and stirring for 10-13 min. The pre-emulsion is obtained after stirring and mixing. The monomer A is selected from at least one of hexadecyl acrylate, octadecyl acrylate and docosyl acrylate, and the monomer B is selected from at least one of acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, acrylamide, methacrylamide, vinyl acetate, methyl acrylate, hydroxyethyl acrylate and hydroxypropyl acrylate;

[0046] S2: adding the initiator and deionized water into the ultrasonic cleaner 5 in a ratio of 1:91, and ultrasonicating for 30-35 min to obtain an initiator aqueous solution. The initiator is a water-soluble free radical initiator, and the water-soluble free radical initiator is selected from at least one of ammonium persulfate, potassium persulfate and sodium persulfate;

[0047] S3: The operator controls remotely through the central control platform, adds 20% pre-emulsified liquid into the vertical reaction kettle 1, adds 20% initiator aqueous solution into the liquid injection tank 11, controls the heating element in the vertical reaction kettle 1 to heat the temperature to 80±1℃, and the stirring motor speed is 150 rpm;

[0048] S4: After reaching the set temperature, the operator adds the initiator aqueous solution in the liquid injection tank 11 into the vertical reaction kettle 1, the injection rate is controlled at 0.13-0.14 kg / min, and the injection time is set to 30-35 min. The pre-emulsified liquid and the initiator aqueous solution are preliminarily mixed in a ratio of 35:2-35:3;

[0049] S5: After preliminary mixing, the remaining 80% pre-emulsified liquid is added into the vertical reaction kettle 1, and the remaining 80% initiator aqueous solution is added into the liquid injection tank 11. The injection rate of the pre-emulsified liquid is set to 1.5-1.6 kg / min, and the injection rate of the initiator aqueous solution is set to 0.09-0.1 kg / min. The injection is synchronized, and after the injection is completed, the stirring is continued for 2-2.5 h;

[0050] S6: After sufficient stirring, the pre-emulsified liquid and the initiator aqueous solution react to form a polymer product solution, which is naturally cooled to room temperature;

[0051] S7: The operator opens the liquid outlet valve four 15, and the cooled polymer product solution is discharged into the standing tank 4. After standing for 24 h, the liquid is filtered to obtain a crude polymer emulsion;

[0052] S8: The crude polymer emulsion is pumped into the air drying oven 6 using the liquid pump 20. The air temperature in the air drying oven 6 is controlled at 60℃-63℃, and the crude polymer emulsion is dried for 12-18 h to form a wax inhibitor. The waste heat gas generated during the drying process is introduced into the jacket 24 of the vertical reaction kettle 1 in step S3 to assist in preheating. The waste heat gas entering the jacket 24 preliminarily preheats the vertical reaction kettle 1, and the heating power of the heating element is controlled according to the real-time temperature after preheating.

[0053] The percentages of all components refer to the percentage of the total mass of the system.

[0054] The implementation mode of the embodiment is:

[0055] In the process of preparing the crude oil wax inhibitor and pour point depressant, first, add octadecyl acrylate 39 kg (monomer A), acrylic acid and acrylamide 9 kg (monomer B, mass ratio 2:1), Tween-80 (surfactant) 2 kg and 300 L of deionized water into the mixing barrel 3 in turn, start the homogenizer 2 to stir at 3000 rpm for 10 min to obtain a uniform pre-emulsion. At the same time, add 0.22 kg of potassium persulfate and 20 L of deionized water into the ultrasonic cleaner 5, and ultrasonic for 30 min to prepare the initiator aqueous solution.

[0056] Through remote operation of the central control platform, first, add 70 kg of pre-emulsion to the vertical reaction kettle 1, and add 4.044 kg of initiator aqueous solution to the liquid injection tank 11, control the heating element of the reaction kettle to raise the temperature to 80℃, and adjust the stirring motor to 150 rpm. After reaching the set temperature, control the liquid injection tank 11 to inject the initiator aqueous solution into the vertical reaction kettle 1 at a rate of 0.133 kg / min, and continue for 30 min to complete the preliminary mixing; then, add the remaining 280 kg of pre-emulsion at a rate of 1.556 kg / min, and the remaining 16.176 kg of initiator aqueous solution at a rate of 0.095 kg / min into the vertical reaction kettle 1 synchronously, for 3 h, and continue to stir for 2.2 h after the injection is completed.

[0057] After the reaction is completed, the polymer product solution is naturally cooled to room temperature, the liquid outlet valve 15 is opened to discharge it into the standing tank 4, and after standing for 24 h, the crude emulsion is obtained by filtering through the composite filter membrane 23, the liquid pump 20 is started, and the crude emulsion is sent into the air drying oven 6, dried at 60℃ for 12 h, and the waste heat gas generated during drying is introduced into the jacket 24 to assist in preheating the mixture entering the vertical reaction kettle 1 next time. The heating element detects that the preheating temperature is 47℃, the original heating power is adjusted smaller, and the stirring space temperature is maintained at 80℃. Finally, a brownish yellow viscous wax inhibitor and pour point depressant is obtained.

[0058] The wax-proofing and pour-point depressant pilot product is sampled and analyzed by Fourier infrared spectrometer (IR) and nuclear magnetic resonance hydrogen spectrum (1HNMR). The test results are compared with the infrared and nuclear magnetic charts of the laboratory product and the pilot product, and it is found that the RAFT (Reversible Addition-Fragmentation Chain Transfer) emulsion polymerization product is basically consistent. When the dosage of the agent is 150 ppm, the pour point of the crude oil (condensation point 16℃) is reduced to 0℃, the pour point of the Shixi crude oil is reduced to 4℃ after 24 hours, and the pour point of the Shixi crude oil is reduced to 10℃ after 72 hours. The RAFT (Reversible Addition-Fragmentation Chain Transfer) emulsion polymerization product refers to a functional polymer dispersion with precise amphiphilic block structure and nanogel particle morphology synthesized by controllable free radical polymerization technology; the product becomes the core active ingredient of the wax-proofing and pour-point depressant of the application due to its designability at the molecular level and unique spatial stability, and solves the problems of low efficiency and poor universality of the traditional pour-point depressant.

[0059] Example Three

[0060] The difference from Example Two is that:

[0061] 1. Add octadecyl acrylate (monomer A) 40 kg, maleic anhydride (monomer B) 8 kg, Tween-80 (surfactant) 2 kg and deionized water 300 L into the mixing barrel 3 in sequence.

[0062] 2. Set the homogenizer 2 to stir for 12 min.

[0063] 3. Add ultrasonic cleaner 5 for 32 min.

[0064] 4. The drying time is 15 h.

[0065] The pre-emulsion in the case has no stratification and no excess foam, and there is no violent polymerization or caking in the reaction kettle. The product is a clear coarse emulsion after standing and filtering, and is a uniform white powder after drying. Performance testing shows that when the dosage of the agent is 150 ppm, the pour point of the crude oil (condensation point 16℃) is reduced to 4℃, the wax crystal dispersion efficiency is ≥90%, and the waste heat recovery system reduces the preheating energy consumption of the reaction kettle by 12%, which meets the stability of industrial production.

[0066] Example Four

[0067] 1. Add a compound of hexadecyl acrylate and docosyl acrylate (monomer A, mass ratio 1:1) 39 kg, acrylamide (monomer B) 10 kg, Span-80 (surfactant) 1 kg and deionized water 300 L into the mixing barrel 3 in sequence.

[0068] 2. Add initiator 0.217 kg and deionized water 19.747 kg into the ultrasonic cleaner 5.

[0069] The case selects the propylene glycol hexadecyl ester and the propylene glycol docosyl ester complex with higher long-chain alkyl content and the Span-80 surfactant with stronger oil solubility, and matches the synchronous injection rate, and finally the product shows excellent performance: when the additive amount is 150 ppm, the freezing point of the crude oil (freezing point 16℃) is reduced to 2℃, the wax prevention rate of the waxy crude oil reaches 85%, and the wax crystal morphology is changed from the large aggregate state to the dispersed fine particles (particle size ≤5μm).

[0070] According to the freezing point reduction amplitudes of 16℃ of example two, 12℃ of example three and 14℃ of example four, the freezing point reduction effect of example two is the best, so example two is the optimal example.

[0071] Comparative example one

[0072] The difference from example two is that:

[0073] 1. Add propylene glycol octadecyl ester (monomer A) 39 kg, maleic anhydride (monomer B) 5.5 kg, Tween-80 (surfactant) 5.5 kg, and deionized water 300 L into the mixing barrel 3 in turn.

[0074] 2. The heating element temperature is set to 85℃.

[0075] In this case, the composition of monomer B and non-ionic surfactant is adjusted, a large amount of fine foam appears at the beginning of stirring, the foam height reaches 1 / 3 of the volume of the mixing barrel, and it is difficult to dissipate; during the stirring process when the temperature reaches 85℃, it is found that the viscosity of the system is abnormally low (25 mPa·s is measured, and the normal viscosity should be 45-50 mPa·s). When the additive amount is 150 ppm, the freezing point of the crude oil (freezing point 16℃) is only reduced to 15℃, the thermal decomposition rate of the product reaches 12%, the wax crystal dispersion particle size is ≥15μm, a large amount of agglomerates appear during the reaction process, and effective wax prevention and freezing point reduction cannot be achieved, and a small amount of irritating gas is generated during the waste heat recovery process due to the decomposition of the product, which needs to be treated additionally, increasing the environmental protection cost.

[0076] Comparative example two

[0077] The difference from example two is that:

[0078] 1. Add propylene glycol hexadecyl ester and propylene glycol docosyl ester complex (monomer A) 20.5 kg, acrylamide (monomer B) 20.7 kg, Span-80 (surfactant) 8.8 kg, and deionized water 300 L into the mixing barrel 3 in turn.

[0079] 2. Set the rate of 0.2 kg / min to inject the initiator aqueous solution into the liquid injection tank.

[0080] In the case, the ratio of monomer A, monomer B and Span-80 (surfactant) is adjusted, and the injection rate of initiator aqueous solution is changed. It is found that the temperature in the reactor rises from 81℃ to 85℃ in the first 5 minutes; when the injection time is 10 minutes, the temperature rises to 90℃, and a large amount of bubbles is generated in the reactor, the volume expansion of the bubbles causes the pressure in the reactor to rise from normal pressure to 0.12MPa, the safety valve is slightly triggered, and a small amount of steam is released; after drying, the product is a dark brown brittle solid with white powder attached to the surface. When the dosage of the agent is 150ppm, the freezing point of the crude oil (freezing point 16℃) is only reduced to 15℃, the thermal decomposition rate of the product is 25%, the wax crystal dispersion particle size is ≥20μm, the system is seriously layered, and the unreacted monomer is left, and the wax inhibition and pour point depression performance is completely invalid. In addition, the waste heat gas generated during drying contains a small amount of irritating substances, which causes slight corrosion to the inner wall of the jacket when it is introduced into the jacket for preheating, affecting the service life of the equipment.

[0081] According to the experiments of example two, example three, example four, comparative example one and comparative example two, it is found that when the content of the components in example two, example three and example four is distributed according to the "acrylic acid ester monomer A with long chain alkyl: 10%-12%, olefin functional monomer B containing carboxyl, acid anhydride group, amide group or ester group: 2.5%-3%, surfactant: 0.3%-0.6%" set by the present application, the effect of crude oil pour point depression and wax inhibition is good; in comparative example one and comparative example two, the ratio and injection rate are adjusted, and abnormal conditions such as high temperature and foaming occur during the process, and the effect of crude oil pour point depression and wax inhibition is very poor.

[0082] The above is only an embodiment of the present application, and the specific structure and characteristics of the scheme are not described in detail. It should be pointed out that for those skilled in the art, without departing from the structure of the present application, a number of modifications and improvements can be made, which should be regarded as the protection scope of the present application, and these will not affect the effect and practicality of the patent. The protection scope claimed in this application should be subject to the content of its claims, and the specific implementation mode and the like recorded in the specification can be used to explain the content of the claims.

Claims

1. A system for preparing a crude oil anti-waxing and pour point depressant, characterized in that, The apparatus includes a vertical reactor (1), a homogenizer (2), a mixing tank (3), a settling tank (4), an ultrasonic cleaner (5), and a forced-air drying oven (6). The homogenizer (2) is connected to the mixing tank (3). The mixing tank (3) is connected to a liquid outlet pipe (7). The liquid outlet pipe (7) is equipped with a liquid outlet valve (8). The liquid outlet pipe (7) is connected to the vertical reactor (1). The ultrasonic cleaner (5) is connected to a liquid outlet pipe (9). The liquid outlet pipe (9) is equipped with a liquid outlet valve (10). The vertical reactor (1) is equipped with a liquid injection tank (11). The liquid outlet pipe (9) is connected to the liquid injection tank (11). The liquid injection tank (11) is connected to a liquid outlet pipe (12). The liquid outlet pipe (12) is equipped with a liquid outlet valve (13). The liquid outlet pipe (12) is connected to a liquid outlet pipe (12). The liquid outlet pipe (12) is equipped with a liquid outlet valve (13). 2) Connected to a vertical reactor (1), the bottom of the vertical reactor (1) is provided with a liquid outlet pipe four (14), the liquid outlet pipe four (14) is provided with a liquid outlet valve four (15), the liquid outlet pipe four (14) is connected to a settling tank (4), the settling tank (4) is provided with a detachable filter assembly, the bottom end of the settling tank (4) is provided with a drain pipe (16), the drain pipe (16) is provided with a drain valve (17), the side wall of the settling tank (4) is connected to a suction pipe (18), the suction pipe (18) is provided with a suction valve (19), the suction pipe (18) is connected to a suction pump (20), the settling tank (4) is provided with a liquid level sensor (21), the liquid level sensor (21) is electrically connected to the suction valve (19), and the suction pipe (18) is connected to a forced-air drying oven (6).

2. The system for preparing a crude oil anti-waxing and pour point depressant according to claim 1, characterized in that, The filter assembly includes a frame (22) and a composite filter membrane (23), the composite filter membrane (23) being nested within the frame (22), and the composite filter membrane (23) being composed of a polypropylene nonwoven fabric layer (2301), a glass fiber layer (2302), and a polytetrafluoroethylene microporous membrane layer (2303).

3. The system for preparing a crude oil anti-waxing and pour point depressant according to claim 1, characterized in that, The vertical reactor (1) has a jacket (24) on its outer wall, and the air outlet of the blower drying box (6) is provided with an air collecting hood (25). An exhaust pipe (26) is connected to the air collecting hood (25), and the exhaust pipe (26) is connected to the jacket (24).

4. The system for preparing a crude oil anti-waxing and pour point depressant according to claim 3, characterized in that, The jacket (24) is provided with a condensate drain pipe (27) at the bottom, and a condensate drain valve (28) is provided on the condensate drain pipe (27).

5. The system for preparing a crude oil anti-waxing and pour point depressant according to claim 1, characterized in that, The discharge valve 1 (8), discharge valve 2 (10), discharge valve 3 (13), discharge valve 4 (15), drain valve (17), pumping valve (19), pumping pump (20), homogenizer (2), vertical reactor (1), and liquid level sensor (21) are all electrically connected to the PLC controller, and the PLC controller is communicatively connected to the central control platform.

6. A method for preparing a crude oil anti-waxing and pour point depressant using the system according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1: Add the following to the mixing tank (3): 10%-12% of acrylate monomer A with long-chain alkyl groups, 2.5%-3% of olefin functional monomer B containing carboxyl, anhydride, amide or ester groups, 0.3%-0.6% of nonionic surfactant, and 84.4%-87.2% of deionized water. All percentages of the above components refer to their mass percentage of the total mass of the system. Mix the components using the homogenizer (2). Set the speed of the homogenizer (2) to 3000 rpm and the mixing time to 10-13 min. After mixing, a pre-emulsion is obtained. S2: Add the initiator and deionized water to the ultrasonic cleaner (5) at a mass ratio of 1:91 and sonicate for 30-35 minutes to obtain an initiator aqueous solution; S3: The operator remotely controls the vertical reactor (1) to add 20% of the total pre-emulsion volume of the pre-emulsion liquid to the vertical reactor (1), and adds 20% of the total initiator aqueous solution volume of the initiator aqueous solution to the injection tank (11). The operator controls the heating element in the vertical reactor (1) to heat the temperature to 80±1℃ and the stirring motor speed to 150rpm. S4: After reaching the set temperature, the operator adds the initiator aqueous solution in the injection tank (11) to the vertical reactor (1), the injection rate is controlled at 0.13-0.14 kg / min, the injection time is set at 30-35 min, and the pre-emulsion and initiator aqueous solution are initially mixed at a mass ratio of 35:2-35:

3. S5: After initial mixing, add the remaining 80% pre-emulsion to the vertical reactor (1) and add the remaining 80% initiator aqueous solution to the injection tank (11). Set the injection rate of the pre-emulsion to 1.5-1.6 kg / min and the injection rate of the initiator aqueous solution to 0.09-0.1 kg / min, and inject them simultaneously. After injection, continue stirring for 2-2.5 h. S6: After thorough stirring, the pre-emulsion reacts with the initiator aqueous solution to form a polymer product solution, and then allows it to cool naturally to room temperature; S7: The operator opens the discharge valve four (15) and discharges the cooled polymer product solution into the settling tank (4). After settling for 24 hours, the solution is separated and filtered to obtain a crude polymer emulsion. S8: The polymer crude emulsion is pumped into the blower drying oven (6) using the pump (20). The air temperature in the blower drying oven (6) is controlled at 60℃~63℃. The polymer crude emulsion is dried for 12-18 hours to finally form a wax-resistant decondensing agent. The waste heat generated during the drying process is introduced into the jacket (24) of the vertical reactor (1) in step S3 for auxiliary preheating.

7. The method for preparing a crude oil anti-waxing and pour point depressant according to claim 6, characterized in that, In step S1, monomer A is selected from at least one of hexadecyl acrylate, octadecyl acrylate, and dodecyl acrylate.

8. The method for preparing a crude oil anti-waxing and pour point depressant according to claim 6, characterized in that, In step S1, monomer B is selected from at least one of acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, acrylamide, methacrylamide, vinyl acetate, methyl acrylate, hydroxyethyl acrylate, and hydroxypropyl acrylate.

9. The method for preparing a crude oil anti-waxing and pour point depressant according to claim 6, characterized in that, In step S2, the initiator is a water-soluble free radical initiator, which is selected from at least one of ammonium persulfate, potassium persulfate, and sodium persulfate.

10. The method for preparing a crude oil anti-waxing and pour point depressant according to claim 6, characterized in that, In step S8, the waste heat gas entering the jacket (24) preheats the vertical reactor (1), and the heating power of the heating element is controlled according to the real-time temperature after preheating.

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