Quantitative method for determining compatibility and stability of blended oil through variable-temperature spots

Abstract

The invention relates to a quantitative method for determining compatibility and stability of blended oil through variable-temperature spots. Comprising the following steps: in a certain temperature range, quantitatively dropping mixed oil samples with different mixing proportions obtained by isothermal mixing on measurement filter paper to obtain liquid drops, carrying out layered diffusion on the liquid drops to obtain spot images, and representing the compatibility and stability of the mixed oil samples through the spot images. According to the method, a sufficient basis is provided for selecting the blending temperature under the condition of determining the blending ratio, the blending oil conveying stability is improved, and the blending oil conveying difficulty and cost are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of quantitative characterization methods for compatibility and stability of crude oil or fuel oil after blending, and in particular to a quantitative method for determining the compatibility and stability of blended oil by temperature-varying spots. Background Art

[0002] The spot test is an experimental method that directly reflects the colloidal stability and wax precipitation of crude oil or fuel oil. Typically, the spot test is conducted at 50°C for crude oil and 100°C for fuel oil, providing a simple measure of the colloidal stability of crude oil or fuel oil. However, in actual production, the two oil products often mix under non-isothermal conditions during mixing, or the feedstock oil cannot be heated to the standard temperature. Therefore, if the colloidal stability of the blend is still assessed according to the standard, the reference value is limited. In view of this, the present invention provides a quantitative method for determining the compatibility and stability of blended oils using variable temperature spot testing. Summary of the Invention

[0003] The technical problem to be solved by this invention is to provide a quantitative method for determining the compatibility and stability of blended oils using temperature-varying spots. This method aims to provide a sufficient basis for determining the blending temperature under blending ratio conditions, thereby improving the stability of blended oil delivery and reducing the difficulty and cost of blended oil delivery.

[0004] The technical solution of the present invention to solve the above technical problems is as follows:

[0005] A quantitative method for determining the compatibility and stability of blended oils by temperature-varying spots comprises the following steps: within a certain temperature range, quantitatively dropping blended oil samples of different blending ratios obtained by isothermal mixing onto measurement filter paper to obtain droplets, and characterizing the compatibility and stability of the blended oil samples by obtaining spot images through stratified diffusion of the droplets.

[0006] On the basis of the above technical solution, the present invention can also be improved as follows.

[0007] Furthermore, the method includes the following specific steps: mixing different types of oil samples to prepare blended oil samples with different blending ratios, heating measuring filter paper and the blended oil sample to the same specific temperature (for example, in an oven), quantitatively dropping the blended oil sample on the measuring filter paper to obtain droplets, and obtaining a spot image by stratification and color distribution of the droplets, characterizing the compatibility and stability of the blended oil sample based on the stratification and color distribution of the spot image, thereby determining the blending boundaries at different temperatures.

[0008] The blending boundary refers to the blending ratio of two raw oils at which spots of the two raw oils blended at a certain temperature do not undergo stratification or color difference.

[0009] Furthermore, the specific steps of quantitatively dropping the mixed oil sample on the measuring filter paper to obtain droplets are: sucking out the mixed oil sample with a quantitative small dropper, allowing the first drop of the mixed oil sample to fall naturally, and dropping the second drop of the mixed oil sample on the measuring filter paper to obtain droplets.

[0010] Furthermore, the volume of the droplet is 0.010±0.005 ml.

[0011] Furthermore, the oil sample includes high wax oil and / or low wax oil.

[0012] Furthermore, the blended oil sample includes a crude oil blended oil sample or a fuel oil blended oil sample.

[0013] Furthermore, if the blended oil sample is a raw oil blended oil sample, the blended oil samples of different blending ratios obtained by isothermal mixing are quantitatively dropped onto a measuring filter paper in a temperature range of 40°C to 70°C to obtain droplets;

[0014] If the blended oil sample is a fuel oil blended oil sample, the blended oil samples with different blending ratios obtained by isothermal mixing are quantitatively dropped onto a measuring filter paper in a temperature range of 80° C. to obtain droplets.

[0015] Furthermore, the blended oil samples with different blending ratios include crude oil blended oil samples with different blending ratios or fuel oil blended oil samples with different blending ratios.

[0016] Furthermore, the blending ratios of the stock oil blended oil samples with different blending ratios include 0:10, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 2:8, 9:1, and 10:0;

[0017] The blending ratios of the fuel oil blended oil samples with different blending ratios include 0:10, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 2:8, 9:1, and 10:0.

[0018] Furthermore, the measuring filter paper is chromatographic grade quantitative filter paper or surface-modified special quantitative filter paper.

[0019] The beneficial effects of the present invention are as follows: the quantitative method of the present invention completely overcomes the problem that the spot test is not practical, is rough and cannot effectively reflect the compatibility and stability during crude oil blending. Under quantitative conditions, the blending ratio during blending can be determined, or when determining the blending ratio, a reasonable blending temperature can be determined, providing a strong basis for on-site operations, reducing the difficulty and loss of transportation of blended crude oil, and avoiding the waste of heat costs caused by excessive heating during transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1The results of spot experiments on five crude oils at 40℃, 50℃, 60℃ and 70℃ are shown;

[0021] Figure 2 The results of the spot test of crude oil blending at 40°C are shown;

[0022] Figure 3 The results of the spot test on crude oil blended at 50°C are shown;

[0023] Figure 4 The results of the spot test of crude oil blending at 60°C are shown;

[0024] Figure 5 The results of the spot test on crude oil blended at 70°C are shown. DETAILED DESCRIPTION

[0025] The principles and features of the present invention are described below. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in this field or the product instructions are used. Where the manufacturers of the reagents or instruments used are not specified, they are all conventional products that can be purchased through regular channels.

[0026] This embodiment relates to a quantitative method for determining the compatibility and stability of blended oils by using temperature-varying spots, comprising the following steps: within a certain temperature range, quantitatively dropping blended oil samples of different blending ratios obtained by isothermal mixing onto measurement filter paper to obtain droplets, and characterizing the compatibility and stability of the blended oil samples by obtaining a spot image through the layered diffusion of the droplets.

[0027] This embodiment preferably includes the following specific steps: mixing different oil samples to prepare blended oil samples with different blending ratios; heating the measurement filter paper and the blended oil sample to the same specific temperature (e.g., in an oven); dropping a fixed amount of the blended oil sample onto the measurement filter paper to form droplets; and generating a speckle image by stratification and color distribution of the droplets. Characterizing the compatibility and stability of the blended oil sample based on the stratification and color distribution of the speckle image, thereby determining the blending boundary at different temperatures. The specific criteria are shown in Table 1.

[0028] Table 1 Quantitative criteria for sample stability or compatibility

[0029]

[0030] Note: *The spot diameter and diffusion diameter can be determined by measuring with a ruler.

[0031] The blending boundary refers to the blending ratio of two raw oils at which spots of the two raw oils blended at a certain temperature do not undergo stratification or color difference.

[0032] Preferably, in this embodiment, the specific steps of quantitatively dropping the mixed oil sample on the measuring filter paper to obtain droplets are: sucking out the mixed oil sample with a quantitative small dropper, allowing the first drop of the mixed oil sample to fall naturally, and dropping the second drop of the mixed oil sample on the measuring filter paper to obtain droplets.

[0033] Preferably, in this embodiment, the volume of the droplet is 0.010±0.005 ml.

[0034] In this embodiment, the oil sample preferably includes high wax oil and / or low wax oil.

[0035] In this embodiment, the blended oil sample preferably includes a crude oil blended oil sample or a fuel oil blended oil sample.

[0036] Preferably, in this embodiment, if the blended oil sample is a raw oil blended oil sample, the blended oil samples of different blending ratios obtained by isothermal mixing are quantitatively dropped onto a measuring filter paper within a temperature range of 40°C to 70°C to obtain droplets; if the blended oil sample is a fuel oil blended oil sample, the blended oil samples of different blending ratios obtained by isothermal mixing are quantitatively dropped onto a measuring filter paper within a temperature range of 80°C to 120°C to obtain droplets.

[0037] In this embodiment, preferably, the blended oil samples with different blending ratios include raw oil blended oil samples with different blending ratios or fuel oil blended oil samples with different blending ratios.

[0038] Preferably, in this embodiment, the blending ratios of the crude oil blending samples with different blending ratios include 0:10, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 2:8, 9:1, and 10:0; the blending ratios of the fuel oil blending samples with different blending ratios include 0:10, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 2:8, 9:1, and 10:0.

[0039] Preferably, in this embodiment, the measuring filter paper is chromatographic grade quantitative filter paper or surface-modified special quantitative filter paper.

[0040] The present invention will be further described below with reference to Examples 1 and 2.

[0041] Example 1: Compatibility and stability of crude oil blending

[0042] The specific method of this embodiment is as follows: a spot test is conducted at different temperatures between 40°C and 70°C. Oil samples are prepared by mixing high-wax oil A (Zhongyuan crude oil) with low-wax oils B, C, D, and E (two Saudi crude oils and two Brazilian crude oils, respectively). The oil samples are aspirated with a quantitative dropper and dripped onto measurement filter paper. After a period of time, the spread of the oil droplets is observed. The blended oil samples include blending ratios of 0:10, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 2:8, 9:1, and 10:0. The measurement filter paper refers to chromatographic-grade quantitative filter paper, and standard quantitative filter paper is used.

[0043] The specific experimental method is as follows: Place a pre-prepared oil sample in a constant temperature oven for one hour. After the oil sample reaches the predetermined temperature, let it rest at the set temperature for one hour. Meanwhile, dry the filter paper in a 100°C oven for at least 10 minutes. Then, use a thermostated, quantitative dropper to aspirate a predetermined amount of the oil sample. Allow the first drop to fall naturally back into the conical flask. Quickly, place the second drop onto the oven-dried filter paper. Allow the droplet to diffuse freely on the filter paper, eventually forming a spot. Compare the resulting spot with a standard reference chart for the spot test to determine the sample's compatibility.

[0044] The obtained spots are compared with the standard reference map of the spot experiment to determine the stability or compatibility of the sample. In an optimized solution of the quantitative characterization method of the stability of crude oil blending described in the present invention, the modified component is: different crude oils are mixed and prepared under isothermal conditions.

[0045] From the attached Figure 1 As can be seen, under varying temperature testing conditions, compared to the five crude oils, crude oil A alone exhibits significant spotting at temperatures of 40°C and 50°C, with the ratio of spot diameter to diffusion diameter ranging from 20% to 40%. Low-wax crude oils B, C, D, and E are all relatively stable between 40°C and 70°C, indicating that high-wax crude oil A is the primary factor affecting the stability of crude oil blends.

[0046] For different types of crude oils with different proportions, the temperature was changed and spot tests were performed. Figures 2 to 5 Changing the temperature will affect the compatibility of crude oil blends. The spot test results from 40°C to 70°C can be used to preliminarily evaluate the compatibility of crude oils. It can be seen that:

[0047] For the same crude oil type and blending ratio, the lower the blending temperature, the worse the compatibility between the crude oils. High-wax crude oil A, low-wax crude oil D, and low-wax crude oil C blended in ratios ranging from 2:8 to 9:1 were incompatible at 50°C or below. High-wax crude oil A and low-wax crude oil B blended in ratios ranging from 4:6 to 9:1 were incompatible at 50°C or below. High-wax crude oil A and low-wax crude oil E blended in ratios ranging from 4:6 to 9:1 were incompatible at 50°C or below. All other blending ratios were compatible at 40°C, 50°C, 60°C, and 70°C.

[0048] Based on the spot test results at different temperatures, crude oils A and E exhibit the best compatibility, followed by crude oil A and B. Compatibility with crude oils C and D is relatively poor. Temperature-variable testing reveals that these poorly compatible crude oils are already very noticeable at temperatures between 50°C and 40°C. For two crude oils with good compatibility, a slightly higher blending ratio is acceptable at the same blending temperature. This suggests that there are no overly stringent technical requirements for blending ratios and temperatures.

[0049] Example 2: Compatibility and stability of fuel oil blending

[0050] The specific method of this embodiment is as follows: a spot test is conducted at different temperatures between 80°C and 120°C. Oil samples of high-wax fuel oil A mixed with low-wax fuel oils B, C, D, and E are prepared and dripped onto filter paper. The oil droplets are then observed for a period of time. The blended oil samples include blending ratios of 0:10, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 2:8, 9:1, and 10:0. The filter paper is chromatographic-grade quantitative filter paper or surface-modified, specially formulated quantitative filter paper.

[0051] The specific experimental method is as follows: Place the oil sample to be tested in a constant temperature oven for 1 hour. After the oil sample in the bottle reaches the predetermined temperature, let it sit at the set temperature for 1 hour. At the same time, dry the filter paper in a 100°C oven for at least 10 minutes. Then, use a constant temperature quantitative dropper to aspirate a predetermined amount of the oil sample. The first drop of oil sample is allowed to fall naturally back into the conical flask. Then, quickly place the second drop of oil sample on the filter paper that has just been dried in the oven. The droplet on the filter paper is then allowed to diffuse freely. After the diffusion is complete, spots will form on the filter paper. The resulting spots are then compared with the standard reference chart of the spot test to determine the compatibility of the sample. The resulting spots are compared with the standard reference chart of the spot test to determine the stability or compatibility of the sample.

[0052] In summary, the variable temperature spotting method of the present invention breaks away from the limitation of the specified temperature and conforms to the actual working conditions of blending under isothermal conditions or non-isothermal conditions in the production of oil blending and distribution. The spotting experiment can provide a more accurate basis for the temperature and blending ratio of the blended crude oil during blending and transportation, thereby improving the efficiency of blending in production, improving the stability of the blended crude oil, reducing transportation costs, and reducing the consumption and waste of heat resources.

[0053] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A quantitative method for determining the compatibility and stability of blended oils by temperature-varying spots, characterized in that: The method comprises the following steps: within a certain temperature range, quantitatively dropping mixed oil samples of different blending ratios obtained by isothermal mixing on a measuring filter paper to obtain droplets, and obtaining a spot image by layered diffusion of the droplets, and characterizing the compatibility and stability of the mixed oil sample by using the spot image.

2. A quantitative method for determining the compatibility and stability of blended oil by temperature-varying spots according to claim 1, characterized in that: The method comprises the following specific steps: mixing different kinds of oil samples to prepare blended oil samples with different blending ratios, heating measuring filter paper and the blended oil samples to the same specific temperature, quantitatively dropping the blended oil samples on the measuring filter paper to obtain droplets, and obtaining a spot image by stratified diffusion of the droplets, characterizing the compatibility and stability of the blended oil sample according to the stratification and color distribution of the spot image, thereby determining the blending boundaries at different temperatures.

3. A quantitative method for determining the compatibility and stability of blended oil by temperature-varying spots according to claim 2, characterized in that: The specific steps of quantitatively dropping the mixed oil sample on the measuring filter paper to obtain liquid droplets are: sucking out the mixed oil sample with a quantitative small dropper, allowing the first drop of the mixed oil sample to fall naturally, and dropping the second drop of the mixed oil sample on the measuring filter paper to obtain liquid droplets.

4. A quantitative method for determining the compatibility and stability of blended oil by temperature-varying spots according to claim 3, characterized in that: The volume of the droplet is 0.010±0.005 ml.

5. A quantitative method for determining the compatibility and stability of blended oil by temperature-varying spots according to claim 2, characterized in that: The oil sample includes high wax oil and / or low wax oil.

6. A quantitative method for determining the compatibility and stability of blended oil by temperature-varying spots according to claim 1, characterized in that: The blended oil sample includes a crude oil blended oil sample or a fuel oil blended oil sample.

7. A quantitative method for determining the compatibility and stability of blended oil by temperature-varying spots according to claim 6, characterized in that: If the blended oil sample is a raw oil blended oil sample, the blended oil samples with different blending ratios obtained by isothermal mixing are quantitatively dropped on a measuring filter paper in a temperature range of 40°C to 70°C to obtain droplets; If the blended oil sample is a fuel oil blended oil sample, the blended oil samples with different blending ratios obtained by isothermal mixing are quantitatively dropped on a measuring filter paper within a temperature range of 80° C. to 120° C. to obtain droplets.

8. A quantitative method for determining the compatibility and stability of blended oil by temperature-varying spots according to claim 6, characterized in that: The blended oil samples with different blending ratios include crude oil blended oil samples with different blending ratios or fuel oil blended oil samples with different blending ratios.

9. A quantitative method for determining the compatibility and stability of blended oil by temperature-varying spots according to claim 8, characterized in that: The blending ratios of the crude oil blended oil samples with different blending ratios include 0:10, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 2:8, 9:1, and 10:0; The blending ratios of the fuel oil blended oil samples with different blending ratios include 0:10, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 2:8, 9:1, and 10:

0.

10. A quantitative method for determining the compatibility and stability of blended oil by temperature-varying spots according to claim 1, characterized in that: The measuring filter paper is chromatographic grade quantitative filter paper or surface-modified special quantitative filter paper.

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