Device and method for evaluating performance of crude oil demulsifier

Abstract

The invention discloses a crude oil demulsifier performance evaluation device and method.The device comprises a contact angle tester and a bearing device, the contact angle tester comprises a tester body, an automatic rotating platform and a microsyringe, the microsyringe is located over the automatic rotating platform, and the bearing device comprises a watch glass, a bracket and a heating assembly; the watch glass is used for loading crude oil and is mounted on the bracket, and the heating assembly is mounted in the bracket. The method comprises loading crude oil into a watch glass; the method comprises the following steps: respectively preparing a plurality of demulsifier solutions with the concentration of 5-100mg / L, and respectively dripping the plurality of demulsifier solutions onto the crude oil; respectively measuring a plurality of contact angles between various demulsifier solutions and the crude oil by using a contact angle tester; the demulsifiers corresponding to relatively small contact angles are screened out and are inspected through a bottle test method in sequence, and the demulsifier with the best demulsification and desalination effects on crude oil is rapidly obtained. According to the method, part of demulsifiers suitable for demulsifying crude oil can be quickly screened out, and the detection efficiency of a bottle test method is improved.

Description

Technical Field

[0001] This invention relates to the field of crude oil processing technology, specifically to a device and method for evaluating the performance of crude oil demulsifiers. Background Technology

[0002] Crude oil dehydration is a crucial step in the crude oil production process, and crude oil demulsifiers are indispensable chemical additives in this process. Because crude oil demulsifiers are highly selective for different types of crude oil and have a narrow application range—no single demulsifier is universally applicable to demulsifying and desalting crude oils with diverse properties—it is necessary to screen for suitable demulsifiers before demulsifying and desalting crude oils. Existing methods for screening demulsifiers include bottle testing, static electrostatic dehydration, static sedimentation, and dynamic electrostatic dehydration. However, static electrostatic dehydration and static sedimentation are static methods and cannot be well matched with the equipment, while dynamic electrostatic dehydration requires larger equipment, consumes more materials, and is less economical. Therefore, the bottle test method is currently commonly used for demulsifier screening. The specific process is as follows: a certain amount of crude oil demulsifier is added to the crude oil emulsion, thoroughly mixed, and then allowed to settle and dehydrate at a constant temperature. The amount of water removed at different times is recorded, and the color of the removed wastewater and the oil-water interface are observed. The water content of the purified oil and the oil content of the wastewater are measured to test the performance of the crude oil demulsifier. Although the bottle test method and testing instruments are relatively simple, many types of demulsifiers need to be tested and screened individually using this method. The workload is large and tedious, resulting in low efficiency in demulsifier screening. Summary of the Invention

[0003] The present invention aims to provide a crude oil demulsification performance evaluation device and method that can perform preliminary screening of demulsifiers and reduce the number of demulsifier varieties tested by bottle testing.

[0004] To solve the above technical problems, the specific solution adopted by the present invention is a crude oil demulsifier performance evaluation device, including a contact angle tester. The contact angle tester includes a tester body, an automatic rotating platform and a micro-injector installed on the tester body. The micro-injector is located directly above the automatic rotating platform. It also includes a support device, which includes a surface dish for loading crude oil, a bracket for supporting the surface dish, and a heating component for heating the crude oil in the surface dish. The surface dish is installed on the bracket, and the heating component is installed inside the bracket.

[0005] As an optimized solution for the above-mentioned crude oil demulsifier performance evaluation device: the bracket is cylindrical, the curvature of the upper end of the bracket is consistent with the curvature of the bottom of the surface dish, and the upper edge of the bracket is flush with the upper edge of the surface dish.

[0006] As another optimized solution for the above-mentioned crude oil demulsifier performance evaluation device: the heating component includes an electric heating wire, a temperature sensor, a controller installed in the bracket, and an external power supply installed outside the bracket. The external power supply is connected to the electric heating wire, the temperature sensor, and the controller respectively through wires.

[0007] A method for evaluating the performance of crude oil demulsifiers, specifically including the following steps:

[0008] S1: Pour the crude oil into a petri dish;

[0009] S2: Prepare various demulsifier solutions with concentrations of 5-100 mg / L, and drop each demulsifier solution onto crude oil in a petri dish; then use a contact angle meter to measure the multiple contact angles between the various demulsifier solutions and crude oil.

[0010] S3: Screen out the demulsifiers with relatively small contact angles and test them one by one using the bottle test method to quickly obtain the demulsifier with the best effect on crude oil demulsification and desalting.

[0011] As an optimized scheme for the above-mentioned crude oil demulsifier performance evaluation method: five demulsifier solutions with concentrations of 5-100 mg / L were prepared, namely demulsifier 1 solution, demulsifier 2 solution, demulsifier 3 solution, demulsifier 4 solution, and demulsifier 5 solution; the contact angles between the five demulsifier solutions and crude oil were measured by a contact angle tester as follows: contact angle 1, contact angle 2, contact angle 3, contact angle 4, and contact angle 5.

[0012] As another optimization scheme for the above-mentioned crude oil demulsifier performance evaluation method: in step S2 above, the concentration of various demulsifier solutions is 30 mg / L.

[0013] As another optimization scheme for the above-mentioned crude oil demulsifier performance evaluation method: In step S2 above, the demulsifier solution is dripped into the crude oil using a micro-syringe in the contact angle tester, and the amount of demulsifier solution drawn into the micro-syringe is 1-5 μL.

[0014] As another optimization scheme for the above-mentioned crude oil demulsifier performance evaluation method: the intake volume of the demulsifier solution in the micro-syringe is 2μL.

[0015] As another optimization of the above-mentioned crude oil demulsifier performance evaluation method: in step S2 above, the temperature at which the contact angle tester measures the contact angle between crude oil and demulsifier solution is lower than the initial distillation temperature of crude oil.

[0016] As another optimization of the above-mentioned crude oil demulsifier performance evaluation method: In step S1 above, the liquid surface of the crude oil in the petri dish is flush with the upper edge of the petri dish, the liquid surface of the crude oil in the petri dish is smooth and flat, and the edge of the crude oil liquid surface in contact with the inner sidewall of the petri dish is continuous.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The surface dish of this invention can be used to hold crude oil. A bracket is provided at the bottom of the surface dish, and the surface dish is mounted on the upper end of the bracket. The curvature of the bottom of the surface dish is consistent with the curvature of the top of the bracket, and the upper edge of the surface dish is flush with the upper side edge of the bracket. A heating component is provided inside the bracket. The heating component is designed to heat the crude oil contained in the surface dish, so that when the contact angle tester measures the contact angle between the demulsifier solution and the crude oil, its temperature is lower than the initial distillation temperature of the crude oil. A high-performance demulsifier must be highly effective in disrupting the interfacial film of crude oil emulsions. This requires the demulsifier to possess good diffusion and adsorption properties, wetting and film-forming properties, and flocculation and agglomeration properties. The diffusion and adsorption properties of a demulsifier refer to the diffusion rate and adsorption capacity of demulsifier molecules into the oil-water interfacial film. Good diffusion properties indicate high compatibility between the crude oil and the demulsifier, resulting in a smaller contact angle. Therefore, the contact angle between crude oil and the demulsifier-containing solution can be measured, and the compatibility between the demulsifier and crude oil can be determined based on the size of the contact angle, thus evaluating the demulsification performance of the demulsifier. This invention achieves rapid evaluation of the compatibility between the demulsifier and crude oil by measuring the contact angle, enabling preliminary screening of demulsifiers. This reduces the number of samples required for bottle testing of demulsifiers, improves the efficiency of demulsifier detection and evaluation, and significantly reduces the workload of testing personnel. Attached Figure Description

[0019] Figure 1 A schematic diagram of a surface dish mounted on a bracket;

[0020] Figure 2 This is a schematic diagram illustrating the performance evaluation of crude oil demulsifiers after they are dripped into crude oil.

[0021] Reference numerals: 1. Surface dish; 2. Holder; 3. Heating assembly; 301. External power supply. Detailed Implementation

[0022] like Figure 1As shown, a crude oil demulsifier performance evaluation device includes a contact angle tester and a support device. The contact angle tester includes a tester body, on which an automatic rotating platform and a micro-injector are mounted. The micro-injector is located directly above the automatic rotating platform. (The contact angle tester is a conventional technical means well known to those skilled in the art. The figure only shows the micro-injector, crude oil, demulsifier, and the angle between the crude oil and the demulsifier; the tester body and the automatic rotating platform are not shown.)

[0023] The support device includes a petri dish 1, a bracket 2, and a heating element 3. The bracket 2 is cylindrical, and the petri dish 1 is mounted on the upper end of the bracket 2. The curvature of the upper end of the bracket 2 is the same as the curvature of the bottom of the petri dish 1, and the upper edge of the bracket 2 is flush with the upper edge of the petri dish 1. In use, crude oil is filled into the petri dish 1, and the petri dish 1 is moved to the automatic rotating platform of the contact angle tester via the bracket 2, and positioned directly below the micro-injector.

[0024] The heating component 3 is mounted on the bracket 2. The heating component 3 includes an electric heating wire, a temperature sensor, and a controller mounted inside the bracket 2, as well as an external power supply 301 mounted outside the bracket 2. The external power supply 301 is connected to the electric heating wire, the temperature sensor, and the controller via wires, thereby heating the crude oil in the petri dish 1 so that the contact angle tester maintains its temperature below the initial distillation temperature of the crude oil when measuring the contact angle between the demulsifier and the crude oil.

[0025] like Figure 2 As shown, a method for evaluating the performance of crude oil demulsifiers specifically includes the following steps:

[0026] S1: Pour the crude oil into a petri dish;

[0027] In step S1 above, the surface of the crude oil in the petri dish is flush with the upper edge of the petri dish, the surface of the crude oil in the petri dish is smooth and flat, and the edge of the crude oil surface in contact with the inner wall of the petri dish is continuous.

[0028] S2: Prepare various demulsifier solutions with a concentration of 30 mg / L, and drop each demulsifier solution onto crude oil in a petri dish; then use a contact angle meter to measure the multiple contact angles between the various demulsifier solutions and crude oil.

[0029] In step S2 above, five demulsifier solutions with a concentration of 30 mg / L are prepared. The five demulsifier solutions are demulsifier 1 solution, demulsifier 2 solution, demulsifier 3 solution, demulsifier 4 solution, and demulsifier 5 solution. The contact angles between the five demulsifier solutions and crude oil measured by the contact angle tester are contact angle 1, contact angle 2, contact angle 3, contact angle 4, and contact angle 5, respectively.

[0030] In step S2 above, the volume of demulsifier solution drawn into the microsyringe is 2 μL.

[0031] In step S2 above, the temperature at which the contact angle tester measures the contact angle between crude oil and demulsifier solution is lower than the initial distillation temperature of the crude oil.

[0032] S3: Screen out the demulsifiers with relatively small contact angles and test them one by one using the bottle test method to quickly obtain the demulsifier with the best effect on crude oil demulsification and desalting.

[0033] According to the above-mentioned crude oil demulsifier performance evaluation method, five crude oils were first selected, and five corresponding demulsifiers were selected for each crude oil for performance evaluation. The five crude oils were crude oil 1, crude oil 2, crude oil 3, crude oil 4, and crude oil 5; the five corresponding demulsifiers were demulsifier 1, demulsifier 2, demulsifier 3, demulsifier 4, and demulsifier 5. These five demulsifiers were then mixed with water to prepare corresponding demulsifier solutions 1, 2, 3, 4, and 5. Next, the five demulsifier solutions corresponding to crude oil 1 were dropped onto crude oil 1, and the contact angles 1, 2, 3, 4, and 5 between the five demulsifier solutions and crude oil 1 were measured sequentially using a contact angle meter. Then, the demulsifier solutions with relatively small contact angles were screened out, and a small number of screened demulsifiers were subjected to bottle testing to select the most suitable demulsifier for crude oil 1. By following this cycle, a small number of demulsifiers suitable for the corresponding crude oil can be quickly screened out by contact angle analysis before the bottle test. Then, the screened small number of demulsifiers can be tested by the bottle test, which can greatly reduce the workload of bottle test personnel and improve the testing efficiency of the bottle test.

[0034] The invention will be specifically illustrated below through five verification examples:

[0035] Verification Example 1

[0036] Select a density of 0.93 g / cm³ 3 Crude oil 1 with a water content of 5% and five corresponding demulsifiers were prepared. First, each of the five demulsifiers was mixed with water to prepare a 30 mg / L solution. Next, crude oil 1 was placed in a petri dish and positioned on the automatic rotating platform of a contact angle meter. Then, 2 μL of demulsifier solution 1 was drawn into the microsyringe of the contact angle meter. At room temperature, the microsyringe dripped demulsifier solution 1 into crude oil 1. Immediately afterward, the contact angle meter measured the contact angle between demulsifier solution 1 and crude oil 1 as 15°. This process was repeated, and the contact angles between demulsifier solution 2 and crude oil 1 were measured sequentially as follows: 50° for 50°, 80° for 3, 95° for 4, and 121° for 5.

[0037] The five demulsifiers were tested sequentially using the bottle test method at 60℃. The amount of crude oil 1 used was 100 ml, the demulsifier solution concentration was 30 mg / L, and the settling time was 120 min for each. The results of the bottle test for the five demulsifiers are shown in Table 1. Table 1. Results of contact angle analysis and bottle test analysis of crude oil. Note: "-" in the table indicates that the oil content in the wastewater is low and the specific value cannot be detected.

[0038] As shown in Table 1, according to the crude oil demulsifier performance evaluation method, demulsifiers 1 and 2 with relatively small contact angles of less than or equal to 50° were screened out. The demulsification of crude oil 1 by demulsifiers 1 and 2 was tested by bottle test. It was found that the smaller the contact angle between the demulsifier and the crude oil, the more water output, the less water content in the purified oil, and the less oil content in the wastewater in the bottle test, the more suitable it is for demulsifying crude oil 1. That is, the contact angle analysis results are consistent with the bottle test results.

[0039] Verification Example 2

[0040] Select a density of 0.91 g / cm³. 3 Crude oil 2 and five corresponding demulsifiers were used. First, the five demulsifiers were mixed with water to prepare 30 mg / L solutions of each demulsifier. Next, crude oil 2 was placed in a petri dish and placed on the automatic rotating platform of a contact angle meter. Then, 2 μL of demulsifier solution 1 was drawn into the microsyringe of the contact angle meter. At room temperature, the microsyringe dripped demulsifier solution 1 into crude oil 2. Immediately afterward, the contact angle meter measured the corresponding contact angle between demulsifier solution 1 and crude oil 2 as 8°. This process was repeated, and the contact angles between demulsifier solution 2 and crude oil 2 were measured sequentially as follows: 24° for demulsifier solution 2, 76° for demulsifier solution 3, 88° for demulsifier solution 4, and 102° for demulsifier solution 5.

[0041] The five demulsifiers were tested sequentially using the bottle test method at 60℃. The amount of crude oil 2 used was 100 ml, the demulsifier solution concentration was 30 mg / L, and the settling time was 120 min. The results of the bottle test for the five demulsifiers are shown in Table 2. Table 2. Results of contact angle analysis and bottle test method analysis of crude oil. Note: "-" in the table indicates that the oil content in the wastewater is low and the specific value cannot be detected.

[0042] As shown in Table 2, according to the crude oil demulsifier performance evaluation method, demulsifiers 1 and 2 with relatively small contact angles of less than or equal to 50° were screened out. The demulsification of crude oil 2 by demulsifiers 1 and 2 was tested by bottle test. It was found that the smaller the contact angle between the demulsifier and the crude oil, the more water output, the less water content in the purified oil, and the less oil content in the wastewater in the bottle test, the more suitable it is for demulsifying crude oil 2. That is, the contact angle analysis results are consistent with the bottle test results.

[0043] Verification Example 3

[0044] Select a density of 0.89 g / cm³. 3 Crude oil 3 and five corresponding demulsifiers were used. First, the five demulsifiers were mixed with water to prepare 30 mg / L solutions of each demulsifier. Next, crude oil 3 was placed in a petri dish and placed on the automatic rotating platform of a contact angle meter. Then, 2 μL of demulsifier solution 1 was drawn into the microsyringe of the contact angle meter. At room temperature, the microsyringe dripped demulsifier solution 1 into crude oil 3. Immediately afterward, the contact angle meter measured the corresponding contact angle between demulsifier solution 1 and crude oil 3 as 35°. This process was repeated, and the contact angles between demulsifier solution 2 and crude oil 3 were measured sequentially as follows: 5° for 5°, 100° for 100°, 68° for 68°, and 102° for 102°.

[0045] The five demulsifiers were tested sequentially using the bottle test method at 60℃. The amount of crude oil 3 used was 100 ml, the demulsifier solution concentration was 30 mg / L, and the settling time was 120 min for each. The results of the bottle test for the five demulsifiers are shown in Table 3. Table 3. Results of contact angle analysis and bottle test analysis of crude oil. Note: "-" in the table indicates that the oil content in the wastewater is low and the specific value cannot be detected.

[0046] As shown in Table 3, according to the crude oil demulsifier performance evaluation method, demulsifiers 1 and 2 with relatively small contact angles of less than or equal to 50° were screened out. The demulsification of crude oil 3 by demulsifiers 1 and 2 was tested by bottle test. It was found that the smaller the contact angle between the demulsifier and the crude oil, the more water output, the less water content in the purified oil, and the less oil content in the wastewater in the bottle test, the more suitable it is for demulsifying crude oil 3. That is, the contact angle analysis results are consistent with the bottle test results.

[0047] Verification Example 4

[0048] Select a density of 0.87 g / cm³. 3Crude oil 4 and five corresponding demulsifiers were used. First, the five demulsifiers were mixed with water to prepare 30 mg / L solutions of each demulsifier. Next, crude oil 4 was placed in a petri dish and placed on the automatic rotating platform of a contact angle meter. Then, 2 μL of demulsifier solution 1 was drawn into the microsyringe of the contact angle meter. At room temperature, the microsyringe dripped demulsifier solution 1 into crude oil 4. Immediately afterward, the contact angle meter measured the corresponding contact angle between demulsifier solution 1 and crude oil 4 as 25°. This process was repeated, and the contact angles between demulsifier solution 2 and crude oil 4 were measured sequentially as follows: 5° for demulsifier solution 2, 63° for demulsifier solution 3, 68° for demulsifier solution 4, and 96° for demulsifier solution 5.

[0049] The five demulsifiers were tested sequentially using the bottle test method at 60℃. The amount of crude oil 4 used was 100 ml, the demulsifier solution concentration was 30 mg / L, and the settling time was 120 min. The results of the bottle test for the five demulsifiers are shown in Table 4. Table 4. Results of contact angle analysis and bottle test method for crude oil. Note: "-" in the table indicates that the oil content in the wastewater is low and the specific value cannot be detected.

[0050] As shown in Table 4, according to the crude oil demulsifier performance evaluation method, demulsifiers 1 and 2 with relatively small contact angles of less than or equal to 50° were screened out. The demulsification of crude oil 4 by demulsifiers 1 and 2 was tested by bottle test. It was found that the smaller the contact angle between the demulsifier and the crude oil, the more water output, the less water content in the purified oil, and the less oil content in the wastewater in the bottle test, the more suitable it is for demulsifying crude oil 4. That is, the contact angle analysis results are consistent with the bottle test results.

[0051] Verification Example 5

[0052] Select a density of 0.85 g / cm³. 3 Crude oil 5 and five corresponding demulsifiers were used. First, each of the five demulsifiers was mixed with water to prepare a 30 mg / L solution. Next, crude oil 5 was placed in a petri dish and placed on the automatic rotating platform of a contact angle meter. Then, 2 μL of demulsifier solution 1 was drawn into the microsyringe of the contact angle meter. At room temperature, the microsyringe dripped demulsifier solution 1 into crude oil 5. Immediately afterward, the contact angle meter measured the corresponding contact angle between demulsifier solution 1 and crude oil 5 as 25°. This process was repeated, and the contact angles between demulsifier solution 2 and crude oil 5 were measured sequentially as follows: 15° for 15°, 8° for 8°, 53° for 5°, and 79° for 79°.

[0053] The five demulsifiers were tested sequentially using the bottle test method at 60℃. The amount of crude oil used was 100 ml for each test, the demulsifier solution concentration was 30 mg / L for each test, and the settling time was 120 min for each test. The results of the bottle test for the five demulsifiers are shown in Table 5. Table 5. Results of contact angle analysis and bottle test method analysis of crude oil. Note: "-" in the table indicates that the oil content in the wastewater is low and the specific value cannot be detected.

[0054] As shown in Table 5, demulsifiers 1, 2, and 3 with relatively small contact angles of 50° or less were selected based on the crude oil demulsifier performance evaluation method. The water output, purified oil water content, and wastewater oil content of demulsifiers 1, 2, and 3 when demulsifying crude oil 5 were tested using the bottle test method. It was found that the smaller the contact angle between the demulsifier and the crude oil, the more water output and the less water content of the purified oil the corresponding demulsifier had in the bottle test method, and the more suitable it was for demulsifying crude oil 5. That is, the contact angle analysis screening results are consistent with the bottle test analysis results.

[0055] As shown in Experiments 1-5 above, for the same type of crude oil, the smaller the contact angle between the demulsifier and the corresponding crude oil, the more water is produced, the lower the water content of the purified oil, and the lower the oil content of the wastewater during the subsequent bottle test. Therefore, the compatibility between the demulsifier and crude oil can be characterized by the contact angle analysis method, and the results of the contact angle analysis and the bottle test analysis show good consistency. Therefore, the crude oil demulsifier performance evaluation method of this invention can quickly screen out a portion of the demulsifiers for the bottle test, which are the most suitable demulsifiers for the corresponding crude oil demulsification and desalting treatment. Thus, this crude oil demulsifier performance evaluation method has a certain degree of reliability.

Claims

1. A crude oil demulsifier performance evaluation device, comprising a contact angle tester, the contact angle tester comprising a tester body, an automated rotating stage mounted on the tester body, and a microsyringe positioned directly above the automated rotating stage, characterized in that: The carrier device comprises a surface dish (1) for loading crude oil, a bracket (2) for supporting the surface dish (1), and a heating assembly (3) for heating the crude oil in the surface dish (1), the surface dish (1) is mounted on the bracket (2), and the heating assembly (3) is mounted in the bracket (2).

2. The device for evaluating the performance of a crude oil demulsifier according to claim 1, characterized in that: The bracket (2) is cylindrical, the curvature of the upper end of the bracket (2) is consistent with the curvature of the bottom of the surface dish (1), and the upper edge of the bracket (2) is flush with the upper edge of the surface dish (1).

3. The device for evaluating the performance of a crude oil demulsifier according to claim 1, characterized in that: The heating assembly (3) comprises an electric heating wire arranged in the bracket (2), a temperature sensor, a controller, and an external power supply (301) arranged outside the bracket (2), the external power supply (301) is connected with the electric heating wire, the temperature sensor, and the controller through wires.

4. A method for evaluating the performance of a crude oil demulsifier, characterized by: Specifically comprising the following steps: S1: loading crude oil into the surface dish; S2: preparing a plurality of demulsifier solutions with a concentration of 5-100 mg / L, respectively, and dropping the plurality of demulsifier solutions onto the crude oil in the surface dish, respectively; and then using a contact angle tester to measure a plurality of contact angles between the plurality of demulsifier solutions and the crude oil, respectively; S3: screening out demulsifiers corresponding to relatively small contact angles and sequentially testing the demulsifiers by a bottle test method to quickly obtain a demulsifier with the best demulsification and desalination effect on the crude oil.

5. The method for evaluating the performance of crude oil demulsifiers according to claim 4, characterized in that: Five demulsifier solutions with a concentration of 5-100 mg / L are prepared, and the five demulsifier solutions are demulsifier 1 solution, demulsifier 2 solution, demulsifier 3 solution, demulsifier 4 solution, and demulsifier 5 solution; and the contact angles between the five demulsifier solutions and the crude oil measured by the contact angle tester are contact angle 1, contact angle 2, contact angle 3, contact angle 4, and contact angle 5, respectively.

6. The method for evaluating the performance of crude oil demulsifiers according to claim 4, characterized in that: In the above step S2, the concentration of the plurality of demulsifier solutions is 30 mg / L.

7. The method for evaluating the performance of crude oil demulsifiers according to claim 4, characterized in that: In the above step S2, the demulsifier solution is dropped into the crude oil by using a microsyringe in the contact angle tester, and the suction amount of the demulsifier solution in the microsyringe is 1-5 μL.

8. The method for evaluating the performance of crude oil demulsifiers according to claim 7, characterized in that: The suction amount of the demulsifier solution in the microsyringe is 2 μL.

9. The method for evaluating the performance of crude oil demulsifiers according to claim 4, characterized in that: In the above step S2, the temperature when the contact angle tester measures the contact angle between the crude oil and the demulsifier solution is less than the initial distillation temperature of the crude oil.

10. The method for evaluating the performance of crude oil demulsifiers according to claim 4, characterized in that: In the above step S1, the liquid surface of the crude oil loaded in the surface dish is flush with the upper edge of the surface dish, the liquid surface of the crude oil in the surface dish is smooth and flat, and the edge where the liquid surface of the crude oil contacts the inner side wall of the surface dish is coherent.

Images