Crude oil demetalization agent as well as preparation method and application thereof

Abstract

The invention discloses a crude oil demetalization agent as well as a preparation method and application thereof. The crude oil demetalization agent provided by the invention comprises polymer spheres and polymer chain segments grafted on the surfaces of the polymer spheres, the polymer spheres are submicron organic polymer particles, the polymer chain segments have amphipathy, and functional groups on the polymer chain segments are functional groups with metal chelating ability. The crude oil demetalization agent not only has a group with good metal chelating ability, but also has amphipathy, can go deep into an oil phase to be in full contact with metal, and can bring the metal back to a water phase to be separated from the oil phase, so that the removal efficiency of heavy metals in crude oil is improved.

Description

Technical Field

[0001] The present application relates to the technical field of crude oil pretreatment and refining, and in particular to a crude oil demetallizing agent and a preparation method and application thereof. Background Art

[0002] Driven by scientific and technological progress, my country's energy consumption continues to rise, while fossil energy, especially petroleum products, still dominates the energy supply. With the continuous improvement of oil extraction and refining technology, the quality of crude oil has gradually tended to be heavy and inferior. This type of crude oil has a high viscosity, and the proportion of metal elements such as nickel, vanadium, calcium, and iron continues to increase. The presence of these heavy metals will cause catalyst failure, corrosion of refining equipment, and deterioration of downstream petroleum product quality and reduced output during crude oil processing. Therefore, exploring new methods for efficient removal of heavy metals from crude oil has become an urgent challenge facing the petrochemical industry. Summary of the invention

[0003] The present application provides a crude oil demetallization agent and a preparation method and application thereof. The crude oil demetallization agent not only has a group with good metal chelating ability, but also has amphiphilicity. It can penetrate into the oil phase to fully contact the metal, and can also bring the metal back to the water phase and separate it from the oil phase, thereby improving the removal efficiency of heavy metals in crude oil.

[0004] In a first aspect, an embodiment of the present application provides a crude oil demetallization agent, comprising a polymer sphere and a polymer chain segment grafted onto the surface of the polymer sphere, wherein the polymer sphere is a submicron organic polymer particle, the polymer chain segment is amphiphilic, and the functional groups on the polymer chain segment are functional groups with metal chelating ability.

[0005] In some embodiments, the functional groups on the polymer chain segments include at least one of carboxyl groups, hydroxyl groups, ester groups, amino groups, amide groups, and sulfonic acid groups.

[0006] In some embodiments, the polymer spheres include at least one of polystyrene polymer, polymethyl methacrylate, polybutadiene, and polyisoprene.

[0007] In some embodiments, the particle size of the crude oil demetallization agent is 221 nm-681 nm.

[0008] In some embodiments, in the crude oil demetallization agent, the grafting rate of the polymer chain segments on the surface of the polymer spheres is 20%-37%.

[0009] In some embodiments, the surface charge density of the crude oil demetallization agent is 3 μC / cm 2 -10μC / cm 2 .

[0010] In a second aspect, the present application provides a method for preparing a crude oil demetallization agent, comprising the following steps:

[0011] (1) preparing a pre-solution, dissolving a functional group monomer in water to obtain a pre-solution, placing the pre-solution in a reaction vessel, and then dissolving an initiator in water to obtain an initiator solution, and adding the initiator solution into a constant pressure titration funnel for standby use, wherein the functional group monomer is used to form a polymer segment of the crude oil demetallization agent;

[0012] (2) preparing a crude oil demetallization agent, adding a reaction monomer to a previously prepared pre-solution, immersing the reaction vessel in a water bath and stirring, and exhausting the oxygen in the reaction vessel at room temperature by bubbling a nitrogen flow, gradually increasing the polymerization temperature to 70° C.-80° C., slowly adding the initiator solution in the constant pressure titration funnel to the polymerization system of the reaction vessel for reaction, lowering the temperature to room temperature after the reaction, and collecting a polymer emulsion, wherein the reaction monomer is used to form polymer spheres of the crude oil demetallization agent;

[0013] (3) Removing small molecule impurities by dialysis: the polymer emulsion is subjected to dialysis treatment to remove small molecule impurities in the polymer emulsion, thereby obtaining the crude oil demetallization agent.

[0014] In some embodiments, in step (1), the functional group monomer includes at least one of acrylic acid, carboxymethyl chitosan, acrylic acid, 2-acrylamide-2-methylpropane sulfonic acid, chitosan, acrylamide and hydroxyethyl methacrylate.

[0015] In some embodiments, in step (2), the reactive monomer includes at least one of styrene, methyl methacrylate, polybutadiene and polyisoprene.

[0016] In a third aspect, an embodiment of the present application provides an application method of a crude oil demetallizing agent, the application method comprising using the crude oil demetallizing agent to remove metals from non-acidic crude oil.

[0017] It can be seen from the above technical scheme that the present application provides a crude oil demetallizing agent and its preparation method and application. The crude oil demetallizing agent not only has a group with good metal chelating ability, but also has hydrophilic and lipophilic amphiphilicity. After the oil and water are emulsified and mixed, the crude oil demetallizing agent can be located at the oil-water phase interface, and the polymer chain segments grafted on the surface of the polymer sphere can extend into the oil phase, compete with oil-soluble organic compounds such as metal porphyrins, and chelate metal ions such as Ni, V, Fe, and Ca to the crude oil demetallizing agent, thereby transferring them to the water phase through electrical desalting. After that, as the water is removed after electrical desalting, the mass transfer efficiency of the metal ions from the oil phase to the water phase interface can be greatly improved, thereby improving the removal efficiency of heavy metals in crude oil. It can be seen that the crude oil demetallization agent provided in this application is suitable for removing nickel, vanadium, iron, calcium and other metals from crude oil. It can not only penetrate into the oil phase to fully contact the metal, but also bring the metal back to the water phase and separate it from the oil phase. The crude oil demetallization agent of this application can effectively remove nickel, vanadium, iron and calcium from crude oil, and has the advantages of small dosage, low production cost and environmental friendliness. In addition, compared with the core-shell structure demetallization agent with inorganic substances as the core, the demetallization agent in this application uses an organic polymer as the core, so it has better lipophilicity, so that the demetallization agent is more fully in contact with the oil phase, and it can also reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 Schematic diagram of the chemical structure of the crude oil demetallization agent provided in the embodiment of the present application;

[0020] Figure 2 This is a schematic diagram of the working principle of the crude oil demetallization agent provided in the embodiment of the present application;

[0021] Figure 3 This is a schematic flow chart of a method for preparing a crude oil demetallizing agent provided in an embodiment of the present application;

[0022] Figure 4 It is a schematic flow chart of the analytical method for applying crude oil demetallization agent in the metal removal process. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of the present application, the present application will be described more comprehensively with reference to the relevant drawings below. The preferred embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms without departing from the core spirit of the present application and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0025] In order to facilitate understanding of the technical solution of the present application, the technical background involved in the present application will be described in detail below.

[0026] In crude oil, calcium and iron usually form stable chelates with aromatic compounds in crude oil in the form of oil-soluble organic salts, such as cyclopentaneate. The chemical structure of calcium cyclopentaneate is shown in formula (I).

[0027]

[0028] Nickel and vanadium are often found in oil-soluble porphyrin or non-porphyrin complexes. Nickel porphyrin consists of a porphyrin ring and a central Ni 2+ ions, while vanadium porphyrin is composed of (VO) 2+ As the core, it forms a tetrahedral structure that rises upward. These metalloporphyrins are tightly bound to the colloidal asphaltene in crude oil through coordination bonds and covalent bonds, making them difficult to be effectively removed using traditional electro-desalting methods. With the improvement of characterization technology, three types of metalloporphyrins have been identified in crude oil: ETIO (protoporphyrin), DPEP (deoxyphylloerythrin protoporphyrin) and RHODO (rose-red porphyrin). Under the DPEP category, it can be divided into DPEP and DI-DPEP (bicyclodeoxyphylloerythrin protoporphyrin), while RHODO is further divided into RHODO-ETIO (rose-red protoporphyrin), RHODO-DPEP (rose-red deoxyphylloerythrin protoporphyrin) and RHODO-DI-DPEP (rose-red bicyclodeoxyphylloerythrin protoporphyrin).

[0029] At present, the methods for demetallizing crude oil are mainly divided into physical methods and chemical methods. Among them, the physical methods mainly include distillation, adsorption, solvent extraction, acid extraction and filtration. The distillation method is based on the different boiling points of various components of crude oil. The purpose of removing metals can be achieved by separating the parts containing metal elements from other parts by heating treatment and other methods. Because of the high boiling point, most metals are concentrated in residual oil or heavy distillate oil. However, because the removal efficiency of metals by distillation is very limited and the operating conditions are relatively harsh, it is difficult to be applied in industry. The adsorption method is a method of removing metals from crude oil using substances with special structures such as activated carbon and resin. However, the adsorption method is suitable for crude oil with extremely high metal content. This method is costly and will increase the acid value of crude oil. It is currently only in laboratory research and there is no application example. The solvent extraction method is to use organic reagents that can be miscible with metal porphyrins to extract metals from crude oil to achieve the purpose of demetallization. However, because the solvent extraction process has a small amount of processing and takes a long time, the cost is too high and the economic benefits are low. In addition, the solvent will extract some other matrices in the crude oil while extracting the metal. Therefore, the solvent extraction method is not used on a large scale in industry, but is mostly used for the separation and analysis of petroleum metal porphyrins in the laboratory. The acid extraction method is to add a certain amount of strong acid to the crude oil, which will inhibit the complexation reaction between porphyrin and metals such as nickel and vanadium. At the same time, the ionized hydrogen in the acid will replace the central metals such as nickel and vanadium in the metal porphyrin, turning it back into hydrogen porphyrin, and the central metal will become a free metal ion (such as Ni 2+ ) enters the water phase and is separated from the oil phase during the conventional electro-desalting process. At present, the demetallizing agents that can be used for crude oil acid extraction include hydrobromic acid, hydrofluoric acid, hydrochloric acid, sulfuric acid, phosphoric acid and nitric acid, most of which are strong acids. However, since most of the acids used in the acid extraction method are strong acids, too small an input amount cannot achieve the ideal demetallization efficiency, and too large an input amount will cause crude oil emulsification. At the same time, too high an acid value of crude oil will cause corrosion to the pipeline, which is not conducive to the subsequent processing of oil products. Finally, the filtration method uses membrane separation technology. In recent years, a variety of membrane structures with special properties have been applied to oil processing, effectively reducing the viscosity of heavy oil and the content of sulfur and heavy metals in oil products. However, this method has extremely high requirements for the viscosity of crude oil, and crude oil with too high a viscosity cannot effectively pass through the membrane structure. In addition, when the filtration time is too long, the macromolecular asphaltene in the crude oil will block the pores, affecting the further passage of crude oil through the filter membrane, greatly reducing the efficiency. Therefore, the filtration method has rarely been used in industrial production and processing until now.

[0030] Chemical removal methods mainly include hydrogenation, metal passivation and chelation. In the hydrogenation method, metal compounds such as metal porphyrins and cyclopentaneates in crude oil can be decomposed on the catalyst surface through hydrogenation reaction, so that the metal in the compound is deposited on the catalyst surface. The catalytic hydrogenation method can not only hydrogenate some unsaturated hydrocarbons to saturate, but also effectively remove sulfur, nitrogen and heavy metals from crude oil. However, the metal deposits formed by the hydrogenation method will inevitably block the catalyst pores, reduce the activity of the catalyst, and lead to a shorter service life of the catalyst, which is not conducive to industrial application. In catalytic cracking, the Ni deposited on the catalyst is oxidized into Ni in the regenerator. 2+ , then enters the reactor, part of Ni 2+ It is reduced to a low-valent Ni + and Ni 0 , they are better than Ni 2+ The metal passivation method is to add a passivation component and let it react with Ni in the regenerator to produce a more stable compound, making Ni 2+ Not easily reduced Ni + and Ni 0 , thereby inhibiting Ni contamination of the catalyst. At the same time, the acidity of the molecular sieve can be adjusted to reduce the amount of coke. However, in recent years, countries have become more stringent in their environmental protection requirements, and metal passivators used in industry are usually highly toxic, which has largely restricted their development.

[0031] The purpose of chelation separation is to add a substance that can react with metal compounds, a demetallizing agent, to crude oil, which contacts and chelates with metal porphyrins and cyclopentane salts in the oil phase at the oil-water interface, converts them into oil-insoluble substances, dissolves or disperses in water, and settles with the water phase through the electro-desalting process to achieve the removal of metals from crude oil. In recent years, some inorganic and organic substances with strong chelating ability have gradually become a research hotspot due to their advantages of being non-acidic, non-corrosive and highly efficient. The reaction mechanism of the chelation reaction is shown in formula (II):

[0032]

[0033] Strong acids are mainly used as metal chelating agents in industry. Although a wide variety of crude oil demetallizing agents have been widely studied and put into use, and have achieved certain demetallization effects, they still have more or less problems, which affect the demetallization efficiency, oil quality and subsequent processing. The specific problems are as follows:

[0034] (1) Most crude oil demetallization agents are small molecule strong acids. Excessive acidity will cause severe corrosion to the pipelines of oil processing equipment, reduce the efficiency of electrical desalting and the yield of high-quality products, and at the same time cause the acidity of mid- and downstream products to rise sharply, greatly reducing product quality.

[0035] (2) In recent years, the crude oil demetallization agents widely used are mostly hydrophilic small molecules, which are coated by the water phase in the oil-in-water emulsion. However, the heavy metals (especially nickel) in crude oil are mostly present in the deep oil phase, which makes it impossible for the demetallization agent to effectively contact the metal, affecting the removal effect. In addition, although some small molecules with strong lipophilicity can contact the metal, they cannot pull the metal in the oil into the water phase and settle during the electro-desalting process, so the ideal demetallization effect cannot be achieved.

[0036] (3) The synthesis process of the demetallization agent is complicated, the amount of materials required is large, and the cost is too high. At the same time, some phosphorus-containing compounds are discharged with the waste, causing serious pollution to the environment.

[0037] Therefore, it is necessary to provide an efficient, economical, environmentally friendly and non-corrosive crude oil demetallization agent, which not only has a group with good metal chelating ability, but also has a certain amphiphilicity, which can not only penetrate into the oil phase to fully contact the metal, but also bring the metal back to the water phase and separate it from the oil phase, thereby being more conducive to the application of crude oil demetallization in industry.

[0038] Based on this, in the first aspect, an embodiment of the present application provides a crude oil demetallization agent, which includes polymer spheres and polymer chain segments grafted on the surface of the polymer spheres, wherein the polymer spheres are submicron organic polymer particles, the polymer chain segments are amphiphilic, and the functional groups on the polymer chain segments have metal chelating ability.

[0039] Figure 1 The chemical structure diagram of the crude oil demetallization agent provided in the embodiment of the present application is shown. Figure 1 As shown, the crude oil demetallization agent provided in the embodiment of the present application includes two parts, namely, polymer spheres and polymer segments, wherein the polymer segments are grafted onto the surface of the polymer spheres. In addition, the polymer spheres are submicron-sized organic polymer ions, and the polymer segments are amphiphilic (hydrophilic and lipophilic) polymers.

[0040] Figure 2 The schematic diagram of the working principle of the crude oil demetallization agent provided in the embodiment of the present application is shown. Figure 2 As shown, after the oil and water are emulsified and mixed, the crude oil demetallization agent can be located at the interface between the oil phase and the water phase, and the polymer chain segments grafted on the surface of the polymer spheres can extend into the oil phase to compete with oil-soluble organic compounds such as metal porphyrins, and chelate metal ions such as Ni, V, Fe, and Ca to the crude oil demetallization agent, which can then be transferred to the water phase through electrical desalting. As the water is removed after electrical desalting, the mass transfer efficiency of metal ions from the oil phase to the water phase interface can be greatly improved.

[0041] Compared with the core-shell structure demetallizing agent with inorganic core, the demetallizing agent in the present application has an organic polymer as the core, so it has better lipophilicity, so that the demetallizing agent can contact with the oil phase more fully, and can also reduce the production cost.

[0042] In some embodiments, the functional groups on the polymer segments include at least one of carboxyl groups, hydroxyl groups, ester groups, amino groups, amide groups, and sulfonic acid groups.

[0043] In some embodiments, the polymer spheres include at least one of polystyrene polymer, polymethyl methacrylate, polybutadiene, and polyisoprene.

[0044] In some embodiments, the particle size of the crude oil demetallizing agent is 221 nm-681 nm.

[0045] In some embodiments, in the crude oil demetallization agent, the grafting rate of polymer segments on the surface of the polymer spheres is 20%-37%.

[0046] In some embodiments, the surface charge density of the crude oil demetallization agent is 3 μC / cm 2 -10μC / cm 2 .

[0047] In a second aspect, the present application provides a method for preparing a crude oil demetallization agent. Figure 3 The schematic diagram of the preparation process of the crude oil demetallization agent is shown in FIG. Figure 3 As shown, the preparation method comprises the following steps:

[0048] (1) preparing a pre-solution, dissolving a functional group monomer in water to obtain a pre-solution, placing the pre-solution in a reaction vessel, and then dissolving an initiator in water to obtain an initiator solution, and adding the initiator solution to a constant pressure titration funnel for standby use, wherein the functional group monomer is used to form a polymer segment of the crude oil demetallization agent;

[0049] (2) preparing a crude oil demetallization agent, adding a reaction monomer to a previously prepared pre-solution, immersing a reaction vessel in a water bath and stirring, and exhausting oxygen in the reaction vessel at room temperature by bubbling a nitrogen flow, gradually increasing the polymerization temperature to 80° C., slowly adding an initiator solution in a constant pressure titration funnel to the polymerization system of the reaction vessel for reaction, and after the reaction, lowering the temperature to room temperature, collecting a polymer emulsion, wherein the reaction monomer is used to form polymer spheres of the crude oil demetallization agent;

[0050] (3) Removing small molecule impurities by dialysis: The polymer emulsion is dialyzed to remove small molecule impurities in the polymer emulsion and obtain a crude oil demetallization agent.

[0051] In the above preparation method, a soap-free emulsion polymerization method is used to prepare the crude oil demetallizing agent. The preparation method can improve the particle size, grafting rate and charge density of the crude oil demetallizing agent on the basis of retaining the original polymer properties.

[0052] Among them, the inventors have found through experiments that the particle size of the crude oil demetallization agent can be adjusted by controlling the reaction time of the polymerization system in step (2).

[0053] Among them, the inventors have found through experiments that by controlling the addition amount of the functional group monomer in step (1) and the reaction monomer in step (2), the grafting rate of the polymer chain segments on the surface of the polymer sphere can be regulated.

[0054] Among them, the inventors have found through experiments that before collecting the polymer emulsion in step (2), sodium hydroxide can be added to the polymerization system obtained after the reaction, so as to adjust the surface charge density of the crude oil demetallization agent.

[0055] In some embodiments, in step (1), the functional group monomer includes at least one of acrylic acid (AA), carboxymethyl chitosan (CMCS), acrylic acid (AA), 2-acrylamide-2-methylpropane sulfonic acid (AMPS), chitosan (CTS), acrylamide (AM) and hydroxyethyl methacrylate (HEMA).

[0056] In some embodiments, in step (2), the reactive monomer includes at least one of styrene (St), methyl methacrylate (MMA), polybutadiene (PB), and polyisoprene (PI).

[0057] In a third aspect, an embodiment of the present application provides an application method of a crude oil demetallizing agent, which includes using the crude oil demetallizing agent to remove metals from non-acidic crude oil.

[0058] The following are specific preparation examples involved in the above content of the present disclosure. It should be clear that the following examples are only for illustrating the crude oil demetallization agent disclosed above and its preparation method and application, and the specific implementation methods and parameters used therein are only one or several methods in accordance with the numerous processes and methods described above. Those skilled in the art can use other parameters according to the content introduced in this application and prepare the crude oil demetallization agent according to the above method without deviating from the core spirit disclosed in the application.

[0059] The present application uses the following analytical method to test the metal removal effect of the prepared crude oil demetallization agent: The crude oil demetallization agent prepared in each example is used to remove metals from non-acidic crude oil, and the removal rate of various metals (Ni, V, Fe, Ca) is measured. Figure 4 The schematic diagram of the analytical method for the application of crude oil demetallization agent in the metal removal process is shown in FIG. Figure 4As shown, the specific steps of the analysis method include:

[0060] (1) Crude oil preheating and crude oil demetallization agent addition

[0061] Before sampling, the crude oil was mixed evenly, and then 50 g of crude oil was weighed into a beaker and preheated in an oil bath at 90°C for 0.5 h. Crude oil demetallization agent and water (oil-water ratio of 0.1) were added to the preheated crude oil in sequence, and then 10 ppm of FC-9303 demulsifier was added. The mixture was then emulsified using a high-speed shearing machine at a certain mixing intensity (speed: 8 kr / min, shearing time: 2 min) to form an oil-in-water emulsion.

[0062] (2) Electrical desalination

[0063] The mixed emulsion in step (1) was transferred into the sample tube of the electric desalter, and the process parameters of the electric desalter were set, including the electric desalting temperature (120°C), the constant temperature time (10min), the low voltage field strength (500v / cm) and time (20min), the high voltage field strength (1000v / cm) and time (10min) and the sedimentation time (60min). The instrument was turned on and the electric desalting experiment was carried out until the experiment was completed.

[0064] (3) Analysis of collected materials

[0065] After the completion of the electro-desalting, the electro-desalting sample tube was cooled to about 60°C, 3g crude oil sample was weighed in a quartz crucible, and the sample was placed in a muffle furnace for program heating: room temperature was raised to 100°C for 10min, and stayed for 30min, and 100°C was raised to 600°C for 50min, and stayed for 15h, and then the temperature was stopped and dropped to room temperature, and the double gloves were taken out. The completely ash-cured sample was obtained, and after cooling to room temperature, 10ml of 10% HCl solution and 10ml of 10% HNO3 solution were added to the quartz crucible respectively to dissolve the ash, and the solution was heated on an electric furnace, concentrated to about 3ml, and then stopped heating. After cooling, it was fixed to a 100ml volumetric flask with deionized water. While the sample was placed in the muffle furnace for heating, the empty quartz crucible without the crude oil sample was subjected to muffle furnace program heating, acid dissolution and fixed volume, and the metal brought in by the experiment itself was analyzed to ensure the accuracy of the experimental results.

[0066] (4) Analysis and determination

[0067] The analyte collected in step (3) is used to determine the metal content in the sample using an inductively coupled plasma emission spectrometer (ICP).

[0068]

[0069] R represents the crude oil demetallization rate, in %;

[0070] c0 represents the initial metal content of crude oil before the electrical desalting experiment, in ppm;

[0071] c1 represents the metal content of crude oil after the electrical desalting experiment, in ppm;

[0072] c b Indicates the metal content in the blank experiment, in ppm.

[0073] Example 1

[0074] This embodiment provides a crude oil demetallization agent, and the preparation method thereof comprises the following steps:

[0075] (1) preparing a pre-solution, dissolving a functional group monomer (4.6 g of acrylic acid) in water (180 g) to obtain a pre-solution, placing the pre-solution in a reaction vessel (glass flask), and then dissolving an initiator (0.2 g of potassium persulfate) in water to obtain an initiator solution, and adding the initiator solution to a constant pressure titration funnel for standby use, wherein the functional group monomer is used to form a polymer segment of the crude oil demetallization agent;

[0076] (2) preparing a crude oil demetallization agent, adding a reaction monomer (15.4 g of styrene) to a previously prepared pre-solution, immersing a reaction vessel (glass flask) in a water bath and stirring at a speed of 500 rpm, and exhausting oxygen in the reaction vessel at room temperature by bubbling a nitrogen flow, gradually increasing the polymerization temperature to 80° C., slowly adding the initiator solution in the constant pressure titration funnel to the polymerization system of the reaction vessel to react for 10 h, and after the reaction, lowering the temperature to room temperature, collecting a polymer emulsion, wherein the reaction monomer is used to form polymer spheres of the crude oil demetallization agent;

[0077] (3) Removing small molecule impurities by dialysis: The polymer emulsion is dialyzed to remove small molecule impurities in the polymer emulsion and obtain a crude oil demetallization agent.

[0078] Test Example 1

[0079] The crude oil demetallization agent prepared in Example 1 was used as a test object to test the metal removal effect of the crude oil demetallization agent at different dosages. The crude oil in step (1) is non-acidic crude oil, using residual unconverted oil, with a nickel content of 26 ppm, a vanadium content of 57 ppm, an iron content of 86 ppm, and a calcium content of 36 ppm. The dosage of the crude oil demetallization agent and the metal removal rate corresponding to Test Example 1 are shown in Table 1.

[0080] Table 1. Crude oil demetallization agent dosage and metal removal rate corresponding to test example 1

[0081]

[0082] Embodiment 2-9

[0083] The preparation method of the crude oil demetallization agent of Examples 2-9 is basically the same as that of Example 1, except that the reaction time of slowly adding the initiator solution in the constant pressure titration funnel to the polymerization system in the reaction container in step (2) is different. On this basis, the particle size of the crude oil demetallization agent prepared at different reaction times is different. The reaction time of Examples 2-9 and the particle size of the crude oil demetallization agent corresponding to each Example are shown in Table 2.

[0084] Table 2. Reaction conditions and product particle size of Examples 2-9

[0085] Sample No. Reaction time (h) Particle size (nm) Example 2 12 221 Example 3 13 317 Example 4 14 352 Example 5 15 412 Example 6 16 461 Example 7 17 572 Example 8 18 620 Example 9 19 681

[0086] Test Example 2

[0087] This test example is basically the same as test example 1, except that the crude oil demetallizing agent prepared in Examples 2-9 is used as the test object. The amount of crude oil demetallizing agent used in this test example is 1000 ppm. The crude oil demetallizing agent targeted by test example 2 and the metal removal rate corresponding to each crude oil demetallizing agent are shown in Table 3.

[0088] Table 3. Metal removal rates of crude oil demetallizing agents prepared in Examples 2-9

[0089]

[0090] Examples 10-17

[0091] The preparation method of the crude oil demetallization agent of Examples 10-17 is basically the same as that of Example 1, except that the addition amount of the functional group monomer in step (1) and the reaction monomer in step (2) is different. In the crude oil demetallization agent prepared on this basis, the grafting rate of the polymer chain segment on the surface of the polymer sphere is different. The monomer dosage of Examples 10-17 and the grafting rate of the crude oil demetallization agent corresponding to each Example are shown in Table 4.

[0092] Table 4. Monomer dosage and product grafting rate of Examples 10-17

[0093] Sample No. Acrylic acid(g) Styrene(g) Grafting rate (%) Example 10 6.3 13.7 20.58 Embodiment 11 8.2 11.8 24.25 Example 12 9.7 10.3 26.87 Example 13 11.4 8.6 29.07 Embodiment 14 13.1 6.9 31.12 Embodiment 15 14.8 5.2 32.97 Example 16 16.5 3.5 35.64 Embodiment 17 18.2 1.8 36.68

[0094] Test Example 3

[0095] This test example is basically the same as test example 1, except that the crude oil demetallizing agents prepared in Examples 10-17 are used as test objects. The amount of crude oil demetallizing agent used in this test example is 600 ppm. The crude oil demetallizing agents used in test example 3 and the metal removal rates corresponding to the crude oil demetallizing agents are shown in Table 5.

[0096] Table 5. Metal removal rates of crude oil demetallizing agents prepared in Examples 10-17

[0097]

[0098]

[0099] Examples 18-25

[0100] The preparation methods of the crude oil demetallizing agents of Examples 18-25 are basically the same as those of Example 1, except that different amounts of sodium hydroxide are added to the polymerization system obtained after the reaction before collecting the polymer emulsion in step (2). The crude oil demetallizing agents prepared on this basis have different surface charge densities. The amounts of sodium hydroxide used in Examples 18-25 and the surface charge densities of the crude oil demetallizing agents corresponding to each example are shown in Table 6.

[0101] Table 6. Sodium hydroxide dosage and product surface charge density of Examples 18-25

[0102] Sample No. Sodium hydroxide (ml) <![CDATA[Surface charge density (μC / cm 2 )]]> Embodiment 18 0.2 9.78 Embodiment 19 0.4 8.19 Embodiment 20 0.6 7.53 Embodiment 21 0.8 6.12 Embodiment 22 1.0 5.31 Embodiment 23 1.2 4.68 Embodiment 24 1.4 3.97 Embodiment 25 1.6 3.16

[0103] Test Example 4

[0104] This test example is basically the same as test example 1, except that the crude oil demetallizing agents prepared in Examples 18-25 are used as test objects. The amount of crude oil demetallizing agent used in this test example is 800 ppm. The crude oil demetallizing agents used in test example 4 and the metal removal rates corresponding to the crude oil demetallizing agents are shown in Table 7.

[0105] Table 7. Metal removal rates of crude oil demetallizing agents prepared in Examples 18-25

[0106]

[0107] Examples 26-32

[0108] The preparation methods of crude oil demetallization agents of Examples 26-32 are basically the same as those of Example 1, except that the types of functional group monomers in step (1) and reactive monomers in step (2) are different. On this basis, the types of functional group monomers and reactive monomers of Examples 26-32, as well as the crude oil demetallization agents corresponding to each example are shown in Table 8.

[0109] Table 8. Monomer types and preparation of crude oil demetallization agents in Examples 26-32

[0110] Sample No. Functional group monomer Reactive monomer Crude oil demetallization agent Embodiment 26 CMCS MMA PCMCS@PMMA Embodiment 27 AA MMA PAA@PMMA Embodiment 28 AMPS MMA PAMPS@PMMA Embodiment 29 HEMA MMA PHEMA@PMMA Embodiment 30 AM St PAM@PS Embodiment 31 AA PB PAA@PB Embodiment 32 AA PI PAA@PI

[0111] Test Example 5

[0112] This test example is basically the same as test example 1, except that the crude oil demetallizing agents prepared in Examples 26-32 are used as test objects, and the amount of crude oil demetallizing agents used in this test example is 1000 ppm. The crude oil demetallizing agents targeted by test example 5 and the metal removal rates corresponding to the crude oil demetallizing agents are shown in Table 9.

[0113] Table 9. Metal removal rates of crude oil demetallizing agents prepared in Examples 26-32

[0114]

[0115] Test Example 6

[0116] This test example is basically the same as test example 1, except that the crude oil used in step (1) is Luda crude oil, which has a nickel content of 27ppm, a vanadium content of 1ppm, an iron content of 7ppm, and a calcium content of 97ppm. In this test example, the crude oil demetallizing agents prepared in Examples 1, 26-32 are used as test objects, and the amount of the crude oil demetallizing agents used is 1000ppm. The crude oil demetallizing agents targeted by test example 6 and the metal removal rates corresponding to the various crude oil demetallizing agents are shown in Table 10.

[0117] Table 10. Metal removal rates of crude oil demetallizing agents prepared in Examples 1, 26-32

[0118]

[0119]

[0120] The types of crude oil used in Test Examples 5 and 6 are different. The nickel exists in different forms and structures in different oil samples. The asphaltene and colloid contents in different oil samples are different. These two components will form different aggregates with the nickel in the oil samples, thus producing different obstacles to the removal of nickel, which is finally manifested in different nickel removal rates. In addition, the same phenomenon also exists in vanadium, iron and calcium in different oil samples.

[0121] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of the present application.

[0122] The above-described embodiments only express several embodiments of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. It should be understood that, on the basis of the technical solutions provided by the technical personnel in the present application, the technical solutions obtained through logical analysis, reasoning or limited experiments are all within the protection scope of the claims attached to the present application. Therefore, the protection scope of the patent of the present application shall be based on the attached claims, and the specification and drawings may be used to interpret the contents of the claims.

Claims

1. A crude oil demetallization agent, characterized in that: The crude oil demetallizing agent comprises polymer spheres and polymer segments grafted on the surface of the polymer spheres, wherein the polymer spheres are submicron organic polymer particles, the polymer segments are amphiphilic, and the functional groups on the polymer segments are functional groups with metal chelating ability.

2. The crude oil demetallization agent according to claim 1, characterized in that: The functional groups on the polymer chain segments include at least one of carboxyl groups, hydroxyl groups, ester groups, amino groups, amide groups and sulfonic acid groups.

3. The crude oil demetallization agent according to claim 1, characterized in that: The polymer spheres include at least one of polystyrene polymer, polymethyl methacrylate, polybutadiene, and polyisoprene.

4. The crude oil demetallization agent according to claim 1, characterized in that: The particle size of the crude oil demetallization agent is 221nm-681nm.

5. The crude oil demetallization agent according to claim 1, characterized in that: In the crude oil demetallizing agent, the grafting rate of the polymer chain segments on the surface of the polymer sphere is 20%-37%.

6. The crude oil demetallization agent according to claim 1, characterized in that: The surface charge density of the crude oil demetallization agent is 3 μC / cm 2 -10μC / cm 2 .

7. A method for preparing a crude oil demetallization agent, characterized in that: The following steps are involved: (1) preparing a pre-solution, dissolving a functional group monomer in water to obtain a pre-solution, placing the pre-solution in a reaction vessel, and then dissolving an initiator in water to obtain an initiator solution, and adding the initiator solution into a constant pressure titration funnel for standby use, wherein the functional group monomer is used to form a polymer segment of the crude oil demetallization agent; (2) preparing a crude oil demetallization agent, adding a reaction monomer to a previously prepared pre-solution, immersing the reaction vessel in a water bath and stirring, and exhausting the oxygen in the reaction vessel at room temperature by bubbling a nitrogen flow, gradually increasing the polymerization temperature to 70° C.-80° C., slowly adding the initiator solution in the constant pressure titration funnel to the polymerization system of the reaction vessel for reaction, lowering the temperature to room temperature after the reaction, and collecting a polymer emulsion, wherein the reaction monomer is used to form polymer spheres of the crude oil demetallization agent; (3) Removing small molecule impurities by dialysis: the polymer emulsion is subjected to dialysis treatment to remove small molecule impurities in the polymer emulsion, thereby obtaining the crude oil demetallization agent.

8. The method for preparing a crude oil demetallizing agent according to claim 7, characterized in that: In the step (1), the functional group monomer includes at least one of acrylic acid, carboxymethyl chitosan, acrylic acid, 2-acrylamide-2-methylpropane sulfonic acid, chitosan, acrylamide and hydroxyethyl methacrylate.

9. The method for preparing a crude oil demetallization agent according to claim 7, characterized in that: In the step (2), the reactive monomer includes at least one of styrene, methyl methacrylate, polybutadiene and polyisoprene.

10. A method for applying a crude oil demetallization agent, characterized in that: The application method comprises using the crude oil demetallization agent to remove metals from non-acidic crude oil.

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