Modified plant silica demulsifier, preparation method and application thereof

Abstract

The application discloses a modified plant silica demulsifier and a preparation method and application thereof, and belongs to the technical field of demulsifiers. The preparation method of the modified plant silica demulsifier is that: firstly, plant silica minerals are ground and screened, and then at least one of the following methods is adopted to process the plant silica minerals, i.e. chemical oxidation modification, high-temperature calcination modification or amino modification. The prepared plant silica demulsifier can realize demulsification within half a minute only by adding a small amount of the plant silica demulsifier into emulsion and violently shaking. After demulsification, oil droplets rapidly gather into the upper layer, and the water phase becomes clear and transparent. Moreover, the demulsification rate of the prepared novel plant silica demulsifier can reach more than 98% when the novel plant silica demulsifier is used for demulsification treatment of oil-in-water type crude oil emulsion. Therefore, the plant silica demulsifier can be widely applied to oil-in-water type emulsion, and can be used for treatment of crude oil emulsion in crude oil exploitation and in the environmental field of oily wastewater.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of demulsifiers, and particularly relates to a novel modified plant silica demulsifier used at normal temperature, and a preparation method and application thereof. BACKGROUND

[0002] In the oil industry, the gradual increase in the water content of crude oil production fluid caused by groundwater infiltration and water injection development results in the formation of oil-in-water type crude oil emulsion. Crude oil emulsification causes crude oil loss, so demulsification and dewatering treatment must be carried out. Crude oil dewatering is an important link in the process of crude oil production, transportation and refining. The artificially added oil displacement agent in the process of oil production leads to increasingly complex fluid composition; the resin, asphaltene and the like in the crude oil can significantly reduce the oil-water interfacial tension, resulting in stable emulsion and increasing the difficulty of treatment.

[0003] Demulsification is to break the balance of the crude oil emulsion, so that the immiscible oil and water phases in the emulsion are separated out to realize dewatering. Physical, chemical and biological methods are common demulsification methods. Physical methods can be mechanical demulsification, electric demulsification, ultrasonic demulsification and electric demulsification; chemical methods are to use the special properties of demulsifiers to destroy the stability of the oil-water interface film to realize demulsification; biological methods are to use degradable microorganisms. Among them, the physical method has low efficiency and high energy consumption; the chemical method has low dosage and high efficiency; the biological method is environmentally friendly but has not been industrialized.

[0004] The chemical demulsification method has the advantages of trace amount, high efficiency and large treatment scale, and is most widely used in crude oil production. However, the demulsification process of the crude oil emulsion in the prior art needs to be realized at a high temperature, and the preparation cost of the chemical demulsifier is high, which increases the demulsification cost. In order to solve this problem, it is necessary to find new economic materials and appropriate surface treatment to realize low-temperature, high-efficiency and economic demulsification.

[0005] Based on the above reasons, the present application is proposed. SUMMARY

[0006] Based on the above reasons, in view of the problems or defects in the prior art, the purpose of the present application is to provide a modified plant silica demulsifier, a preparation method and application thereof, to solve or at least partially solve the above technical defects in the prior art: the present application solves the problem that the chemical demulsifier needs to be demulsified at a high temperature, and can realize high-efficiency demulsification at normal temperature.

[0007] The purpose of the present application is to overcome the deficiencies of the prior art, provide a novel mineral demulsifier, a preparation method and demulsification treatment of oil-in-water type crude oil emulsion, and realize high-efficiency demulsification at normal temperature.

[0008] In order to achieve one of the above purposes of the present application, the present application adopts the following technical solutions:

[0009] A preparation method of modified plant silica demulsifier, the method specifically comprises the following steps:

[0010] The modified plant silica demulsifier is prepared by grinding and screening the plant silica mineral, and then treating the plant silica mineral by at least one of chemical oxidation modification, high-temperature calcination modification, and amino modification.

[0011] The modified plant silica demulsifier prepared by the method can realize high-efficiency demulsification of oil-in-water crude oil emulsion at room temperature. The demulsifier obtained by chemical oxidation modification is denoted as O-type demulsifier, the demulsifier obtained by high-temperature calcination modification is denoted as C-type demulsifier, and the demulsifier obtained by amino modification is denoted as N-type demulsifier.

[0012] Further, in the preferred embodiment of the present application, the grinding and screening of the plant silica mineral is specifically as follows:

[0013] The plant silica ore is crushed and then manually ground, and the plant silica powder smaller than 100 mesh is screened out by a steel sieve, and then the plant silica is ball milled by a ball mill, and then the plant silica smaller than 800 mesh is screened out by a wet screening method, and finally the nanometer plant silica suspension smaller than 18000 mesh is obtained by ultrasonic screening through a 18000 mesh silk screen. After standing, the nanometer plant silica smaller than 1 um in particle size is obtained after solid-liquid separation, drying, and grinding.

[0014] Preferably, in the above technical solution, the ball milling time is 3-5 h, and more preferably 4 h.

[0015] Preferably, in the above technical solution, the standing time is 12-36 h, and more preferably 24 h.

[0016] Further, in the above technical solution, the chemical oxidation modification is specifically oxidation treatment of the plant silica raw material by using an oxidation reagent, wherein the oxidation reagent is composed of concentrated sulfuric acid and potassium permanganate, or composed of concentrated ammonia water and hydrogen peroxide, or composed of concentrated sulfuric acid and hydrogen peroxide.

[0017] Still further, when the oxidation reagent is composed of concentrated sulfuric acid and potassium permanganate, the chemical oxidation modification method specifically comprises the following steps:

[0018] The nanometer plant silica and the concentrated sulfuric acid are mixed at a ratio and stirred at 0℃ for 10-20 min, and then the solution is diluted by dropwise adding ultrapure water, and the reaction is continued for 10-20 min; then potassium permanganate is added in batches and reacted at 40℃ for 1-3 h. After the reaction is completed, an ice water mixture is slowly added, and then an appropriate amount of H2O2 is added dropwise until the solution turns light gray. After washing, centrifugation, freeze-drying, and grinding, the modified plant silica demulsifier of the present application, i.e., the O-1 type demulsifier, is obtained.

[0019] Preferably, in the technical solution described above, the ratio of the amount of the nano-plant silica and the concentrated sulfuric acid is 1 mass part: 30-50 volume parts, wherein the mass part and the volume part are based on g:mL.

[0020] Preferably, in the technical solution described above, the mass ratio of the nano-plant silica and the potassium permanganate is 1:(2-3).

[0021] Specifically, in the technical solution described above, the purpose of using H2O2 is to react with the excess KMnO4.

[0022] Further, when the oxidizing agent is composed of concentrated ammonia and hydrogen peroxide, the specific steps of the chemical oxidation modification method described above are as follows: the nano-plant silica is mixed with the concentrated ammonia, the hydrogen peroxide and the ultrapure water according to the proportion, and then reacted at a constant temperature of 30-80℃ for 30 min; after the reaction, the mixture is washed, centrifuged, freeze-dried and ground to obtain the modified plant silica demulsifier, i.e. the O-2 type demulsifier.

[0023] Preferably, in the technical solution described above, the reaction temperature is 40℃.

[0024] Preferably, in the technical solution described above, the volume ratio of the concentrated ammonia, the hydrogen peroxide and the ultrapure water is 1:2:7.

[0025] Preferably, in the technical solution described above, the ratio of the amount of the nano-plant silica and the concentrated ammonia is 1 mass part: 1 volume part, wherein the mass part and the volume part are based on g:mL.

[0026] Further, when the oxidizing agent is composed of concentrated sulfuric acid and hydrogen peroxide, the specific steps of the chemical oxidation modification method described above are as follows: the nano-plant silica particles are mixed with the concentrated sulfuric acid and the hydrogen peroxide according to the proportion, and then reacted at a constant temperature of 85℃ for 30 min; after the reaction, the mixture is washed, centrifuged, freeze-dried and ground to obtain the modified plant silica demulsifier, i.e. the O-3 type demulsifier.

[0027] Preferably, in the technical solution described above, the volume ratio of the concentrated sulfuric acid and the hydrogen peroxide is 7:3.

[0028] Preferably, in the technical solution described above, the ratio of the mass of the nano-plant silica and the sum of the volume of the concentrated sulfuric acid and the hydrogen peroxide is 1 mass part:(5-15) volume parts, wherein the mass part and the volume part are based on g:mL.

[0029] More preferably, in the technical solution described above, the ratio of the mass of the nano-plant silica and the sum of the volume of the concentrated sulfuric acid and the hydrogen peroxide is 1 mass part: 12.5 volume parts, wherein the mass part and the volume part are based on g:mL.

[0030] Further, the high-temperature calcination modification method comprises the following steps: calcining the nano-plant silica at 200-700 DEG C for 8 hours, and cooling to room temperature after the calcination is completed to obtain the C-type demulsifier.

[0031] Preferably, the calcination temperature is 600 DEG C.

[0032] Further, the amino-modification method comprises the following steps:

[0033] The nano-plant silica is treated in a polyethyleneimine (PEI) solution with a mass fraction of 1-9% for 1 hour according to the proportion, and after the reaction is completed, the nano-plant silica is washed, centrifuged and freeze-dried to obtain the N-type demulsifier.

[0034] Further, the nano-plant silica and the PEI solution are used in a ratio of 1 part by mass: 20 parts by volume, wherein the parts by mass and the parts by volume are based on g:mL.

[0035] Further, the mass fraction of the PEI solution is preferably 9%.

[0036] The second object of the present application is to provide the modified plant silica demulsifier prepared by the method.

[0037] The third object of the present application is to provide the application of the modified plant silica demulsifier prepared by the method in the demulsification of the oil-in-water crude oil emulsion. The plant silica demulsifier prepared by the present application can realize demulsification within half a minute only by adding a small amount of the demulsifier into the emulsion and shaking vigorously. After the demulsification, the oil droplets are quickly gathered to the upper layer, and the water phase becomes clear and transparent.

[0038] Further, the application comprises the following steps:

[0039] (1) adjusting the pH value of the crude oil emulsion to 2, 4, 6, 7, 8 or 10;

[0040] (2) weighing the modified plant silica demulsifier according to the corresponding gram weight, and dispersing the modified plant silica demulsifier in ultrapure water to obtain a demulsifier dispersion;

[0041] (3) pouring the emulsion obtained in step (1) into the demulsifier dispersion obtained in step (2) according to the corresponding volume, and demulsifying after shaking sufficiently, and then standing.

[0042] Further, the crude oil emulsion in step (1) is prepared by using 9 g of crude oil and 891 g of ultrapure water.

[0043] Further, the pH value of the crude oil emulsion in step (1) is preferably 7.

[0044] Further, the above technical solution, step (3) the corresponding volume can refer to the grammage of step (2), and the amount of demulsifier is 1-1000 mg / L.

[0045] Further, the above technical solution, the oscillation time of step (3) is preferably 1 min.

[0046] Further, the above technical solution, the demulsification temperature of step (3) is room temperature. The room temperature refers to the natural room temperature condition in four seasons, without additional cooling or heating treatment, and the general room temperature is controlled at 10-30 DEG C, preferably 15-25 DEG C.

[0047] Further, the above technical solution, the standing time of step (3) is 0.5-2 h, preferably 1 h.

[0048] The role of each raw material of the application is as follows:

[0049] (1) Plant silica raw material: plant silica as the base material of the application, there is no plant silica mineralization precedent in the world, and a kind of plant silica deposit natural micro-nano silicon-carbon mine is found in Shilukeng of Fengcheng City in Jiangxi Province in recent years. The main component of plant silica is quartz, which is a good hydrophilic material, and organic carbon has good hydrophobicity, so plant silica nanoparticle material itself is a natural interfacial active material. In the application, the particle size of plant silica raw ore is controlled below 1 um, which can increase the specific surface area and improve the demulsification efficiency. All researches are carried out around the nano plant silica after controlling the particle size.

[0050] (2) Oxidizing agent: the oxidizing agent combination used in the application includes concentrated sulfuric acid and potassium permanganate, concentrated ammonia and hydrogen peroxide, and concentrated sulfuric acid and hydrogen peroxide. After the oxidation treatment of plant silica, hydroxyl, carboxyl and other content functional groups will be generated on the surface of plant silica, so that the demulsifier is more hydrophilic, and can be better dispersed in the oil-in-water emulsion, thereby improving the demulsification efficiency.

[0051] (3) Polyethyleneimine: after the treatment of polyethyleneimine, the surface of plant silica will produce positively charged amine groups, which can enhance the interaction with negatively charged oil droplets, thereby improving the demulsification efficiency.

[0052] Compared with the prior art, the application has the following beneficial effects:

[0053] 1. The novel plant silica demulsifier prepared by the application can reach a demulsification rate of more than 98% when used for the demulsification treatment of oil-in-water type crude oil emulsion.

[0054] 2. The novel plant silica demulsifier raw material of the application has stable properties, is non-toxic and harmless, and is economical and practical. The plant silica mineral material has no application precedent, and the plant silica mineral is used for the first time in the preparation of a demulsifier material in the application.

[0055] 3. The plant silica demulsifier material of the application has a simple preparation method, fast demulsification speed, and no special requirements for demulsification conditions, and can be prepared under normal temperature conditions.

[0056] 4. The plant silica demulsifier of the application is used in oil-in-water emulsions, has wide application, and can be used in the treatment of crude oil emulsions in crude oil exploitation and in the field of oily wastewater environment.

[0057] 5. The preparation method of the plant silica demulsifier of the application opens up the application direction of the new plant silica mineral material, and provides a broad application prospect reference for the new mineral. BRIEF DESCRIPTION OF DRAWINGS

[0058] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0059] Figure 1 Fig. (a) is a microstructure diagram of the plant silica raw material used in the application; and Fig. (b) is an EDS test result diagram of the plant silica raw material used in the application;

[0060] Figure 2 Fig. is an XRD spectrum diagram of the plant silica raw material used in the application;

[0061] Figure 3 Fig. is a comparison diagram of the demulsification rates of the O-1 type demulsifier and the plant silica raw material under the conditions of 25 DEG C and pH in the application example 1 and the comparison application example 1;

[0062] Figure 4 Fig. is a comparison diagram of the demulsification rates of the products obtained by different preparation temperatures of concentrated ammonia and hydrogen peroxide in the application example 2 under the conditions of 25 DEG C and pH = 4;

[0063] Figure 5 Fig. is a comparison diagram of the demulsification rates of the modified plant silica demulsifiers obtained by different amounts of mixed solutions in the application example 3 under the conditions of 25 DEG C and pH = 4;

[0064] Figure 6 Fig. is a comparison diagram of the demulsification rates of the modified plant silica demulsifiers obtained by different calcination temperatures in the application example 4 under the conditions of 25 DEG C and pH = 4;

[0065] Figure 7The demulsification rate of the modified diatomite demulsifier prepared by using different PEI concentrations in Example 5 is compared under the condition of 25℃ and pH=4. DETAILED DESCRIPTION

[0066] The application will be further described in detail by examples.

[0067] The equipment and raw materials used in the application can be purchased from the market or are commonly used in the art. The methods in the following examples are conventional methods in the art unless otherwise specified.

[0068] The diatomite raw material used in the preparation of the demulsifier in the following examples of the application is a natural micro-nano silicon-carbon ore of diatomite deposit discovered in Shilukeng, Fengcheng City, Jiangxi Province in recent years. It is the first application of diatomite in the field of demulsification. The chemical element analysis of diatomite is shown in Table 1. The microstructure and EDS results of diatomite are shown in Figure 1 The diatomite is mainly composed of quartz, carbon, pyrite and kaolinite, and its XRD spectrum is shown in Figure 2 The quartz (65.01% to 85.89%) in the main components of diatomite is a good hydrophilic material, while the organic carbon (9% to 20%) has good hydrophobicity, so the diatomite nano-particle material itself is a natural interfacial active material.

[0069] Table 1 Chemical element analysis of diatomite raw ore

[0070]

[0071] Table 2 Element composition of corresponding points in SEM graph (at%)

[0072]

[0073] In the method of breaking the oil-in-water crude oil emulsion in the following application examples of the application, modified diatomite is used as the demulsification material. The oil concentration corresponding to the absorbance is obtained by measuring the absorbance using a UV spectrophotometer after extracting the residual oil in the water phase and the crude oil in the emulsion after demulsification by toluene extraction, and then the demulsification rate is calculated using the demulsification rate calculation formula.

[0074] 1kg of modified diatomite demulsifier can treat 1-2 tons of oil-in-water crude oil emulsion.

[0075] Example 1

[0076] A modified diatomite demulsifier of this example is prepared by a chemical oxidation modification method. Concentrated sulfuric acid and potassium permanganate are selected as the oxidizing agent, and the obtained product is denoted as O-1 type demulsifier. The method comprises the following steps:

[0077] (1) Silica particle size control: The silica ore was crushed and manually ground in a ceramic mortar. The silica with a particle size less than 100 mesh was used for the next grinding step. 200 g of zirconia beads with a diameter of 1 mm and 40 g of silica were placed in a ball mill tank according to a ball-to-material ratio of 5:1. The ball mill was set to a rotation speed of 210 r / min for dry grinding for 4 h. After ball milling, the zirconia beads were poured out and the silica particles were scraped off. The silica was dispersed by adding an appropriate amount of ultrapure water and then wet sieving. The silica was sieved through a 200 mesh, a 500 mesh, and a 800 mesh steel sieve, respectively. Finally, the silica was sieved through a 15000 mesh (750 nm) and a 18000 mesh (500 nm) silk screen under ultrasonic vibration. A nanosilica suspension with a particle size less than 18000 mesh was obtained. After standing for 24 h, the solid and liquid were separated. The silica was dried in an oven at 50°C for 12 h and then ground to a powder in a maroon mortar to obtain nanosilica.

[0078] (2) Chemical oxidation treatment of silica: 1 g of nanosilica prepared in step (1) was added to a 100 ml conical flask, and 46 ml of 98% concentrated H2SO4 was poured into the conical flask. The conical flask was placed in an ice-water mixing device at 0°C and stirred at a speed of 300 r / min for 15 min. Then 5 ml of ultrapure water was added slowly, and the reaction was continued for another 15 min. Subsequently, 2.5 g of KMnO4 was added to the container in small portions, and the stirring was continued in the ice-water mixing device for 15 min. The conical flask was removed and placed in a constant temperature water bath at 40°C for 2 h. Then the reaction mixture was poured into a 500 ml beaker, and 300 ml of ice water was added slowly. The mixture was stirred for 15 min. Then 30% H2O2 was added dropwise until the solution turned light gray. Finally, the excess manganese salt was washed away with an appropriate amount of 1.5 mol / L HCl solution. The product was obtained by repeated washing and centrifugation with ultrapure water. The product was freeze-dried and ground to obtain a modified silica demulsifier, which is referred to as O-1 type demulsifier.

[0079] Example 2

[0080] A modified silica demulsifier prepared by a chemical oxidation modification method, in which concentrated ammonia and hydrogen peroxide are used as oxidizing agents. The product is referred to as O-21 type demulsifier. The method comprises the following steps:

[0081] (1) Silica particle size control, the steps are the same as in step (1) of Example 1. Nanosilica is prepared.

[0082] (2) Chemical oxidation treatment of the phytolith: 0.5 g of the nano-phytolith prepared in step (1) was put into a mixed solution composed of 28% concentrated ammonia water, 30% hydrogen peroxide and ultrapure water at a volume ratio of 1:2:7 (wherein the amount of the concentrated ammonia water was 0.5 ml, the amount of the hydrogen peroxide was 1 ml, and the amount of the ultrapure water was 3.5 ml), and then reacted in a constant-temperature water bath at 30°C for 30 min. Finally, the reacted mixture was repeatedly washed with ultrapure water, and the particles were separated by centrifugation at a speed of 7000 r / min for 8 min to obtain the product. The obtained product was freeze-dried and ground to obtain the O-21 type demulsifier.

[0083] Example 3

[0084] A modified phytolith demulsifier of the present example was prepared by a chemical oxidation modification method. The oxidation reagent was concentrated ammonia water and hydrogen peroxide. The obtained product was recorded as O-22 type demulsifier. The method was basically the same as that of Example 2, except that step (2) of the present example was reacted in a constant-temperature water bath at 40°C. The other steps and process parameters were the same.

[0085] Example 4

[0086] A modified phytolith demulsifier of the present example was prepared by a chemical oxidation modification method. The oxidation reagent was concentrated ammonia water and hydrogen peroxide. The obtained product was recorded as O-23 type demulsifier. The method was basically the same as that of Example 2, except that step (2) of the present example was reacted in a constant-temperature water bath at 50°C. The other steps and process parameters were the same.

[0087] Example 5

[0088] A modified phytolith demulsifier of the present example was prepared by a chemical oxidation modification method. The oxidation reagent was concentrated ammonia water and hydrogen peroxide. The obtained product was recorded as O-24 type demulsifier. The method was basically the same as that of Example 2, except that step (2) of the present example was reacted in a constant-temperature water bath at 60°C. The other steps and process parameters were the same.

[0089] Example 6

[0090] A modified phytolith demulsifier of the present example was prepared by a chemical oxidation modification method. The oxidation reagent was concentrated ammonia water and hydrogen peroxide. The obtained product was recorded as O-25 type demulsifier. The method was basically the same as that of Example 2, except that step (2) of the present example was reacted in a constant-temperature water bath at 70°C. The other steps and process parameters were the same.

[0091] Example 7

[0092] A modified plant silica demulsifier of the present example is prepared by a chemical oxidation modification method. Concentrated ammonia and hydrogen peroxide are selected as the oxidizing agent. The product is recorded as O-26 type demulsifier. The method is basically the same as that of example 2, with the only difference being that step (2) of the present example is reacted in a constant temperature water bath at 80°C, and other steps and process parameters are the same.

[0093] Example 8

[0094] A modified plant silica demulsifier of the present example is prepared by a chemical oxidation modification method. Concentrated sulfuric acid and hydrogen peroxide are selected as the oxidizing agent. The product is recorded as O-31 type demulsifier. The method comprises the following steps:

[0095] (1) Particle size control of plant silica. The step is the same as step (1) of example 1, and nano plant silica is prepared.

[0096] (2) Chemical oxidation treatment of plant silica: 1g of nano plant silica prepared in step (1) is placed into a mixed solution composed of 98% concentrated sulfuric acid and 30% hydrogen peroxide in a volume ratio of 7:3. The total volume of the mixed solution is 5ml. The reaction is carried out in a constant temperature water bath at 85°C for 30min. It is repeatedly washed to neutral, and then the particles are separated by centrifugation at a speed of 7000r / min for 8min to obtain O-31 type demulsifier.

[0097] Example 9

[0098] A modified plant silica demulsifier of the present example is prepared by a chemical oxidation modification method. Concentrated sulfuric acid and hydrogen peroxide are selected as the oxidizing agent. The product is recorded as O-32 type demulsifier. The method is basically the same as that of example 8, with the only difference being that the total volume of the mixed solution in step (2) of the present example is 7.5ml, and other steps and process parameters are the same.

[0099] Example 10

[0100] A modified plant silica demulsifier of the present example is prepared by a chemical oxidation modification method. Concentrated sulfuric acid and hydrogen peroxide are selected as the oxidizing agent. The product is recorded as O-33 type demulsifier. The method is basically the same as that of example 8, with the only difference being that the total volume of the mixed solution in step (2) of the present example is 10ml, and other steps and process parameters are the same.

[0101] Example 11

[0102] A modified plant silica demulsifier of the present example is prepared by a chemical oxidation modification method. Concentrated sulfuric acid and hydrogen peroxide are selected as the oxidizing agent. The product is recorded as O-34 type demulsifier. The method is basically the same as that of example 8, with the only difference being that the total volume of the mixed solution in step (2) of the present example is 12.5ml, and other steps and process parameters are the same.

[0103] Example 12

[0104] A modified diatomite demulsifier of this example is prepared by chemical oxidation modification method, and concentrated sulfuric acid and hydrogen peroxide are selected as oxidation reagents. The product is recorded as O-35 type demulsifier. The method is basically the same as that of Example 8, and the only difference is that the total volume of the mixed solution in step (2) of this example is 15 ml, and other steps and process parameters are the same.

[0105] Example 13

[0106] A modified diatomite demulsifier of this example is prepared by high-temperature calcination modification. The product is recorded as C1 type demulsifier. The method comprises the following steps:

[0107] (1) Particle size control of diatomite, the step is the same as step (1) in Example 1, and nano diatomite is prepared.

[0108] (2) High-temperature calcination treatment of diatomite: 1 g of nano diatomite prepared in step (1) is loaded into a corundum crucible, and is calcined in a muffle furnace at a rate of 10 ℃ / min. After the temperature is raised to 200 ℃, it is kept constant for 8 h. Then the corundum crucible is taken out with tongs and cooled to room temperature. The obtained product is C1 type demulsifier.

[0109] Example 14

[0110] A modified diatomite demulsifier of this example is prepared by high-temperature calcination modification. The product is recorded as C2 type demulsifier. The method is basically the same as that of Example 13, and the only difference is that the calcination temperature used in step (2) of this example is 300 ℃, and other steps and process parameters are the same.

[0111] Example 15

[0112] A modified diatomite demulsifier of this example is prepared by high-temperature calcination modification. The product is recorded as C3 type demulsifier. The method is basically the same as that of Example 13, and the only difference is that the calcination temperature used in step (2) of this example is 400 ℃, and other steps and process parameters are the same.

[0113] Example 16

[0114] A modified diatomite demulsifier of this example is prepared by high-temperature calcination modification. The product is recorded as C4 type demulsifier. The method is basically the same as that of Example 13, and the only difference is that the calcination temperature used in step (2) of this example is 500 ℃, and other steps and process parameters are the same.

[0115] Example 17

[0116] A modified diatomite demulsifier of this example is realized by high temperature calcination modification, the obtained product is recorded as C5 type demulsifier, the method is basically same as example 13, the only difference is that the calcination temperature used in step (2) of this example is 600℃, and other steps and process parameters are the same.

[0117] Example 18

[0118] A modified diatomite demulsifier of this example is realized by high temperature calcination modification, the obtained product is recorded as C6 type demulsifier, the method is basically same as example 13, the only difference is that the calcination temperature used in step (2) of this example is 700℃, and other steps and process parameters are the same.

[0119] Example 19

[0120] A modified diatomite demulsifier of this example is realized by amino modification, the obtained product is recorded as N1 type demulsifier, the method comprises the following steps:

[0121] (1) Particle size control of diatomite, the step is same as step (1) in example 1, nano diatomite is prepared.

[0122] (2) Solution preparation: the original concentration of polyethyleneimine (PEI) in the laboratory is 99%, and the PEI solution with the required concentration for the experiment is prepared. The specific steps are as follows: 0.2ml 99% PEI solution is mixed with 19.8ml ultrapure water to obtain 1% PEI solution;

[0123] (3) Amino modification treatment of diatomite: 1g of nano diatomite prepared in step (1) is treated in 20ml of 1% PEI solution prepared in step (2) for 1h, after repeated washing and centrifugation, the product is obtained, and after freeze-drying and grinding, N1 type demulsifier is obtained.

[0124] Example 20

[0125] A modified diatomite demulsifier of this example is realized by amino modification, the obtained product is recorded as N2 type demulsifier, the method comprises the following steps:

[0126] (1) Particle size control of diatomite, the step is same as step (1) in example 1, nano diatomite is prepared.

[0127] (2) Solution preparation: the original concentration of polyethyleneimine (PEI) in the laboratory is 99%, and the PEI solution with the required concentration for the experiment is prepared. The specific steps are as follows: 0.2ml 99% PEI solution is mixed with 19.8ml ultrapure water to obtain 1% PEI solution;

[0128] (3) Amino-modification of the silica: 1 g of the nano-silica prepared in step (1) was treated in 20 mL of the 3% PEI solution prepared in step (2) for 1 h. After repeated washing and centrifugation, the product was obtained. The product was freeze-dried and ground to obtain the N2 demulsifier.

[0129] Example 21

[0130] The modified silica demulsifier of the present example was achieved by amino-modification. The product was denoted as N3 demulsifier. The method comprises the following steps:

[0131] (1) Particle size control of the silica: The step was the same as step (1) in Example 1, and nano-silica was prepared.

[0132] (2) Solution preparation: The original concentration of polyethyleneimine (PEI) in the laboratory was 99%, and the PEI solution with the required concentration for the experiment was prepared. The specific steps were as follows: 1 ml of 99% PEI solution was mixed with 9 ml of ultrapure water to obtain a 5% PEI solution.

[0133] (3) Amino-modification of the silica: 1 g of the nano-silica prepared in step (1) was treated in 20 mL of the 5% PEI solution prepared in step (2) for 1 h. After repeated washing and centrifugation, the product was obtained. The product was freeze-dried and ground to obtain the N3 demulsifier.

[0134] Example 22

[0135] The modified silica demulsifier of the present example was achieved by amino-modification. The product was denoted as N4 demulsifier. The method comprises the following steps:

[0136] (1) Particle size control of the silica: The step was the same as step (1) in Example 1, and nano-silica was prepared.

[0137] (2) Solution preparation: The original concentration of polyethyleneimine (PEI) in the laboratory was 99%, and the PEI solution with the required concentration for the experiment was prepared. The specific steps were as follows: 1.4 ml of 99% PEI solution was mixed with 18.6 ml of ultrapure water to obtain a 7% PEI solution.

[0138] (3) Amino-modification of the silica: 1 g of the nano-silica prepared in step (1) was treated in 20 mL of the 7% PEI solution prepared in step (2) for 1 h. After repeated washing and centrifugation, the product was obtained. The product was freeze-dried and ground to obtain the N4 demulsifier.

[0139] Example 23

[0140] The modified plant silica demulsifier of the present embodiment is realized by amino modification, and the obtained product is recorded as N5 type demulsifier, and the method comprises the following steps:

[0141] (1) Particle size control of plant silica, the step is the same as step (1) in embodiment 1, and nano plant silica is prepared.

[0142] (2) Solution preparation: 1.8 ml of 99% polyethyleneimine (PEI) solution is mixed with 18.2 ml of ultrapure water to obtain a 9% PEI solution.

[0143] (3) Amino modification treatment of plant silica: 1 g of nano plant silica prepared in step (1) is treated in 20 mL of 9% PEI solution prepared in step (2) for 1 h, and after repeated washing and centrifugation, the product is obtained, and after freeze-drying and grinding, the N5 type demulsifier is obtained.

[0144] Application Example 1

[0145] The demulsification effect of the modified plant silica demulsifier (O-1 type demulsifier) prepared in embodiment 1 on oil-in-water type crude oil emulsion under different pH conditions is studied. The demulsification experiment method used in the present application embodiment comprises the following steps:

[0146] 891 g of ultrapure water with pH of 4 and 9 g of Lanzhou Petrochemical crude oil are poured into a plastic bottle, and after being shaken thoroughly, a Fluko-FA25 type high shear dispersion emulsifier is used to rotate from low speed to high speed (28000 r / min) for 5 min to prepare a stable oil-in-water emulsion with mass fraction of 1%. At room temperature of about 25℃, the emulsion is divided into 6 equal parts according to 150 ml / portion, and the pH is adjusted to 2, 4, 6, 7, 8 and 10 respectively for standby. The emulsion with adjusted pH is further divided into three equal parts, and is used for demulsification effect comparison test of O-1 type demulsifier, blank control group and untreated plant silica raw material respectively.

[0147] The O-1 type demulsifier prepared in Example 1 is weighed at a dosage of 1000 ppm (1 g / L) to a glass sample bottle, and 1 ml of ultrapure water is added to the bottle, followed by ultrasonic treatment for 10 s to disperse the demulsifier. The emulsion with adjusted pH is measured at a dosage of 1000 ppm (the dosage in this application example is 50 ml), poured into the bottle containing the dispersed demulsifier, shaken thoroughly for 1 min, and then left to stand for 1 h. The control group of emulsions at different pH values is also treated by the above method. After standing for 1 h, 5 ml of water phase separated after demulsification is taken from each bottle, 20 ml of toluene is immediately added, and the mixture is shaken for 1 h to extract the residual oil in the water phase. The wavelength of the ultraviolet spectrophotometer is set to 287 nm, and the absorbance of the toluene-extracted crude oil before and after demulsification is measured. The concentration of the crude oil before and after demulsification is calculated by the standard curve y = 7.1819x of the concentration of the crude oil and the absorbance, and the demulsification rate under different pH conditions is calculated according to the demulsification rate formula.

[0148]

[0149] wherein E is the demulsification rate (%), and C0 and C (mg / L) are the initial oil concentration in the emulsion before demulsification and the residual oil concentration in the separated water after demulsification, respectively.

[0150] The above demulsification experiment of this application example can determine that the prepared material has the best demulsification rate at pH 7 under the conditions of room temperature 25°C and a dosage of 1000 ppm.

[0151] Application Example 2

[0152] The six groups of demulsifiers prepared in Examples 2-7, including O-21 type demulsifier, O-22 type demulsifier, O-23 type demulsifier, O-24 type demulsifier, O-25 type demulsifier, and O-26 type demulsifier, are subjected to demulsification experiments under the same conditions to determine the optimal chemical oxidation treatment temperature when concentrated ammonia and hydrogen peroxide are used for chemical oxidation modification.

[0153] The demulsification experiment method used in this application example is basically the same as that in Application Example 1, except that the demulsifiers used in this application example are the six groups of demulsifiers prepared in Examples 2-7, including O-21 type demulsifier, O-22 type demulsifier, O-23 type demulsifier, O-24 type demulsifier, O-25 type demulsifier, and O-26 type demulsifier, and the dosages of the demulsifiers and the demulsification test steps are the same. According to the method of Application Example 1, the dosage of the demulsifier is uniformly 1000 ppm, and the demulsification rates of the six groups of different demulsifiers prepared in Examples 2-7 in an emulsion with pH = 4 (under room temperature conditions) are measured.

[0154] The application embodiment selects the pH = 4 emulsion for demulsification experiment because the emulsion under the pH condition is relatively stable. Figure 4 It can be determined from the demulsification experiment test result (see the attached

[0155] Application Embodiment 3

[0156] The five groups of demulsifiers prepared in embodiments 8-12, including O-31 type demulsifier, O-32 type demulsifier, O-33 type demulsifier, O-34 type demulsifier and O-35 type demulsifier, are subjected to demulsification experiment under the same condition to determine the optimal dosage of the preparation agent when chemical oxidation modification is performed by using concentrated sulfuric acid and hydrogen peroxide.

[0157] The demulsification experiment method adopted in the application embodiment is basically the same as that in application embodiment 1, and the only difference is that the demulsifier adopted in the application embodiment is the five groups of demulsifiers prepared in embodiments 8-12, including O-31 type demulsifier, O-32 type demulsifier, O-33 type demulsifier, O-34 type demulsifier and O-35 type demulsifier, and the dosage of each demulsifier and the demulsification test steps are the same. According to the method of application embodiment 1, the unified dosage of the demulsifier is 1000 ppm, and the demulsification rate that can be reached by the five groups of different demulsifiers in the pH = 4 emulsion (under room temperature condition) is measured.

[0158] The application embodiment selects the pH = 4 emulsion for demulsification experiment because the emulsion under the pH condition is relatively stable. Figure 5 It can be determined from the demulsification experiment test result (see the attached

[0159] Application Embodiment 4

[0160] The six groups of demulsifiers prepared in embodiments 13-18, including C1 type demulsifier, C2 type demulsifier, C3 type demulsifier, C4 type demulsifier, C5 type demulsifier and C6 type demulsifier, are subjected to demulsification experiment under the same condition to determine the optimal calcination temperature when high-temperature calcination modification is selected.

[0161] The demulsification experiment method adopted in the application embodiment is basically the same as that in application embodiment 1, and the only difference is that the demulsifier adopted in the application embodiment is the six groups of demulsifiers prepared in embodiments 13-18, including C1 type demulsifier, C2 type demulsifier, C3 type demulsifier, C4 type demulsifier, C5 type demulsifier and C6 type demulsifier, and the dosage of each demulsifier and the demulsification test steps are the same. According to the method of application embodiment 1, the unified dosage of the demulsifier is 1000 ppm, and the demulsification rate that can be reached by the six groups of different demulsifiers in the pH = 4 emulsion (under room temperature condition) is measured.

[0162] The application embodiment selects the pH = 4 emulsion to carry out the demulsification experiment because the emulsion under the pH condition is relatively stable. Through the demulsification experiment test result (see the attached Figure 6 ) can be determined that the demulsifier prepared at the calcination temperature of 600 DEG C corresponds to the highest demulsification rate.

[0163] Application Example 5

[0164] The five groups of demulsifiers prepared in the examples 19-23, including the N1 type demulsifier, the N2 type demulsifier, the N3 type demulsifier, the N4 type demulsifier and the N5 type demulsifier are carried out the demulsification experiment under the same condition to determine the best PEI concentration when the amino modification treatment is selected. According to the method of the application example 1, the demulsifier amount is uniformly 1000 ppm, and the demulsification rate of the five groups of different products in the pH = 4 emulsion (under the room temperature condition) is measured.

[0165] The application embodiment selects the pH = 4 emulsion to carry out the demulsification experiment because the emulsion under the pH condition is relatively stable. Through the demulsification experiment test result (see the attached Figure 7 ) can be determined that the demulsifier prepared at the PEI concentration of 9% corresponds to the highest demulsification rate.

[0166] Comparative Application Example 1

[0167] The comparative application example is to study the demulsification effect of the oil-in-water type crude oil emulsion under different pH conditions by using the phytolith raw material. The demulsification experiment method used in the comparative application example is basically the same as the application example 1, and the only difference is that the demulsifier used in the application embodiment is the phytolith raw material, and the phytolith raw material amount and the demulsification test steps are the same.

Claims

1. A method for preparing a modified diatomite demulsifier, characterized by: The method specifically comprises the following steps: firstly, grinding and screening the silicate mineral; and then, treating the silicate mineral by at least one of the following methods: chemical oxidation modification, high-temperature calcination modification or amino modification, to obtain the modified silicate demulsifier. The grinding and screening of the silicate mineral is specifically performed as follows: After the silicate ore is crushed and manually ground, the silicate powder with a size less than 100 mesh is screened out by using a steel sieve, and then the silicate with a size less than 800 mesh is obtained by using a ball mill and a wet screening method. Finally, the nanosilica suspension with a size less than 18000 mesh is obtained by using an ultrasonic screening method, and then the nanosilica with a size less than 1 um is obtained by solid-liquid separation, drying and grinding after standing. The specific steps of the amino modification method are as follows: The nanosilica is treated in a polyethyleneimine (PEI) solution with a mass fraction of 1-9% for 1 h, and then the N-type demulsifier is obtained by washing, centrifuging and freeze-drying after the reaction.

2. The method of claim 1, wherein: The chemical oxidation modification is specifically performed by using an oxidizing agent to oxidize the silicate raw material, wherein the oxidizing agent is composed of concentrated sulfuric acid and potassium permanganate, or composed of concentrated sulfuric acid and hydrogen peroxide.

3. The method of claim 2, wherein: When the oxidizing agent is composed of concentrated sulfuric acid and potassium permanganate, the chemical oxidation modification method specifically comprises the following steps: The nanosilica is stirred with concentrated sulfuric acid at 0°C for 10-20 min, and then the solution is diluted by adding ultrapure water dropwise, and the reaction is continued for 10-20 min. Then, potassium permanganate is added in batches, and the reaction is carried out at 40°C for 1-3 h. After the reaction is completed, ice water mixture is slowly added, and then an appropriate amount of H2O2 is added dropwise until the solution turns light gray. The modified silicate demulsifier, i.e., the O-1 type demulsifier, is obtained by washing, centrifuging, freeze-drying and grinding after the reaction.

4. The method of claim 2, wherein: When the oxidizing agent is composed of concentrated sulfuric acid and hydrogen peroxide, the specific steps of the chemical oxidation modification method are as follows: the nanosilica particles are mixed with concentrated sulfuric acid and hydrogen peroxide at 85°C for 30 min. After the reaction is completed, the modified silicate demulsifier, i.e., the O-3 type demulsifier, is obtained by washing, centrifuging, freeze-drying and grinding.

5. The method of claim 1, wherein: The specific steps of the high-temperature calcination modification method are as follows: the nanosilica is calcined at 200-700°C for 8 h, and then cooled to room temperature to obtain the C type demulsifier.

6. The modified silicate demulsifier prepared by the method of any one of claims 1-5.

7. The application of the modified silicate demulsifier prepared by the method of any one of claims 1-5 in the demulsification of oil-in-water crude oil emulsion.

8. Use according to claim 7, characterized in that: The steps of the application are specifically as follows: (1) adjusting the pH value of the crude oil emulsion to 2, 4, 6, 7, 8 or 10; (2) weighing the modified silicate demulsifier, and then ultrasonically dispersing the demulsifier in ultrapure water to obtain a demulsifier dispersion; (3) taking the emulsion obtained in step (1) in a corresponding volume, and then pouring it into the demulsifier dispersion obtained in step (2), and then fully shaking to demulsify, and then standing.

Images