Method for detecting salinity of water in oil

Abstract

The invention discloses a method for detecting the salinity of water in oil, which comprises the following steps: step a, uniformly mixing an oil sample, measuring a sample, adding a non-polar solvent into the sample, and uniformly mixing to obtain a sample mixed solution; step b, carrying out centrifugal treatment on the sample mixed solution, standing, carrying out oil-water separation on the sample mixed solution, obtaining a mixed solution of a non-polar solvent and oil liquid on the upper layer of the sample mixed solution, and obtaining a water phase on the lower layer of the sample mixed solution; c, according to the volume of the water phase separated from the sample mixed solution, carrying out water volume adaptation treatment to obtain a detection water sample; and step d, sucking the detection water sample, dripping the detection water sample on a refraction prism of the seawater salinity detector, obtaining the salinity concentration in the detection water sample, and determining whether the water sample is seawater or fresh water according to the salinity concentration of the water sample.

Description

Technical Field

[0001] This application relates to the field of environmental monitoring technology, and in particular to a method for detecting the salinity of water in oil. Background Technology

[0002] Oil contamination with water is a common malfunction during the operation and repair of ship equipment. Quickly determining whether the water mixed in the oil is seawater or freshwater is crucial for identifying the source of leakage, assessing equipment damage, and developing maintenance strategies. Currently, the industry commonly uses organic solvents to assist in the separation of seawater and freshwater in oil, followed by qualitative identification through methods such as evaporation crystallization, chemical precipitation, or conductivity testing.

[0003] However, these conventional methods have significant shortcomings in practical applications. Traditional static stratification is inefficient; when the water content in the oil is extremely low, a single operation may not yield enough water to meet testing requirements, making successful testing difficult. Furthermore, the oil typically carries impurities and particulate matter, resulting in poor cleanliness of the separated aqueous phase, directly affecting observation results and leading to misjudgments. In addition, traditional conductivity testing is easily interfered with by impurities such as metal abrasive particles in the oil, resulting in insufficient overall stability and accuracy, making it unsuitable for the practical needs of rapid and reliable on-site testing on ships. Summary of the Invention

[0004] The purpose of this invention is to provide a method for detecting the salinity of water in oil, which can solve the above-mentioned problems existing in the prior art.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] On the one hand, a method for detecting the salinity of water in oil is provided, including: Step a: After mixing the oil sample, measure the sample, add a non-polar solvent to the sample and mix evenly to obtain the sample mixture. Step b: Centrifuge the sample mixture, and after standing, separate the oil and water in the sample mixture. Obtain a mixture of non-polar solvent and oil in the upper layer of the sample mixture, and obtain an aqueous phase in the lower layer of the sample mixture. Step c: Based on the volume of the aqueous phase separated from the sample mixture, perform water volume adaptation processing to obtain the test water sample; Step d: Take a drop of water sample and place it on the refracting prism of the seawater salinity analyzer to obtain the salt concentration in the water sample. Then, determine whether the water sample is seawater or freshwater based on the salt concentration.

[0007] Preferably, in step b, the centrifugation speed is 2500 r / min to 3500 r / min, and the centrifugation time is 3 min to 8 min.

[0008] Preferably, step c includes: When the volume of the aqueous phase separated from the sample mixture is greater than 0.1 mL and less than 0.2 mL, remove the upper layer of the non-polar solvent and oil mixture from the sample mixture, add the oil sample and non-polar solvent to the remaining sample mixture and mix well, then repeat step b until the volume of the aqueous phase separated from the sample mixture is not less than 0.2 mL.

[0009] Preferably, step c includes: When the volume of the aqueous phase separated from the sample mixture is not greater than 0.1 mL, add 0.1 mL of pure water to the sample mixture and mix well, then repeat step b to obtain a diluted water sample that can be used for detection.

[0010] Preferably, the pure water is deionized water.

[0011] Preferably, the salt concentration of the tested water sample is calculated by multiplying the salt concentration obtained from the dilution of the water sample by the dilution factor corresponding to the dilution of the water sample.

[0012] Preferably, in step d, a micropipette, capillary tube, or pipette is used to aspirate the water sample for testing.

[0013] Preferably, in step d, when the salt concentration in the water sample is not less than 3‰, the water sample is determined to be seawater; when the salt concentration in the water sample is less than 1‰, the water sample is determined to be freshwater.

[0014] Preferably, the nonpolar solvent is xylene or n-hexane.

[0015] Preferably, the oil sample is marine equipment lubricating oil, hydraulic oil, gear oil, or diesel oil.

[0016] The beneficial effects of this application are as follows: This application achieves rapid oil-water separation by mixing the oil sample, measuring the sample, adding a non-polar solvent to form a mixture, and then centrifuging followed by settling. This eliminates the need for settling and significantly shortens the separation time, improving efficiency. Centrifugation effectively removes suspended impurities from the aqueous phase, ensuring the cleanliness and accuracy of subsequent salt content detection. Furthermore, targeted water volume adaptation is applied based on the volume of the separated aqueous phase, employing different treatment methods for different volumes. This solves the problem of insufficient aqueous volume for effective detection while ensuring the reliability of the test results, enabling effective detection in trace water content scenarios and meeting the practical needs of rapid on-site detection on ships. Attached Figure Description

[0017] The present application will now be described in further detail with reference to the accompanying drawings and embodiments.

[0018] Figure 1 This is a block diagram illustrating a method for detecting the salinity of water in oil according to an embodiment of this application.

[0019] Figure 2 This is a block diagram illustrating a method for detecting the salinity of water in oil according to another embodiment of this application. Detailed Implementation

[0020] To make the technical problems solved by this application, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of this application are further described in detail below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0023] This application provides a method for detecting the salinity of water in oil, comprising: step a, mixing an oil sample, measuring the sample, adding a non-polar solvent to the sample and mixing evenly to obtain a sample mixture; step b, centrifuging the sample mixture, allowing it to stand to separate the oil and water, obtaining a mixture of non-polar solvent and oil in the upper layer of the sample mixture, and obtaining an aqueous phase in the lower layer of the sample mixture; step c, performing water volume matching based on the volume of the aqueous phase separated in the sample mixture to obtain a test water sample; step d, placing the test water sample onto the refracting prism of a seawater salinity analyzer to obtain the salt concentration in the test water sample, and then determining whether the water sample is seawater or freshwater based on the salt concentration.

[0024] This application achieves rapid oil-water separation by mixing the oil sample, measuring the sample, adding a non-polar solvent to form a mixture, and then centrifuging followed by settling. This eliminates the need for settling and significantly shortens the separation time, improving efficiency. Centrifugation effectively removes suspended impurities from the aqueous phase, ensuring the cleanliness and accuracy of subsequent salt content detection. Furthermore, targeted water volume adaptation is applied based on the volume of the separated aqueous phase, employing different treatment methods for different volumes. This solves the problem of insufficient aqueous volume for effective detection while ensuring the reliability of the test results, enabling effective detection in trace water content scenarios and meeting the practical needs of rapid on-site detection on ships.

[0025] Figure 1 This is a block diagram illustrating a method for detecting the salinity of water in oil according to an embodiment of this application, as shown below. Figure 1 As shown, this embodiment provides a method for detecting the salinity of water in oil, including: Step a: After mixing the oil sample, measure the sample, add a non-polar solvent to the sample and mix evenly to obtain the sample mixture. Step b: Centrifuge the sample mixture, and after standing, separate the oil and water in the sample mixture. Obtain a mixture of non-polar solvent and oil in the upper layer of the sample mixture, and obtain an aqueous phase in the lower layer of the sample mixture. Step c: Based on the volume of the aqueous phase separated from the sample mixture, perform water volume adaptation processing to obtain the test water sample; Step d: Place a drop of water sample onto the refracting prism of the seawater salinity analyzer to obtain the salt concentration in the water sample. Then, determine whether the water sample is seawater or freshwater based on the salt concentration. It should be noted that different models of seawater salinity analyzers can be used, as long as they have refractive detection capabilities and can accurately obtain the salt concentration.

[0026] This embodiment achieves rapid and thorough oil-water separation by combining non-polar solvent-assisted extraction with centrifugal settling. Compared to traditional settling stratification methods, this significantly shortens separation time and improves detection efficiency. Simultaneously, water volume adaptation effectively solves the problem of ineffective detection due to insufficient aqueous phase volume, making it suitable for scenarios with trace water content. The entire detection process is convenient to operate, requires no complex equipment, and can quickly determine whether it is seawater or freshwater, perfectly meeting the detection needs of shipboard operations and improving the efficiency, adaptability, and accuracy of oil-water salinity detection methods.

[0027] In one embodiment, in step a, if the sample is a mixture of free water and oil, a non-polar solvent may be added. The non-polar solvent may be xylene or n-hexane. The dosage of the non-polar solvent added may be 5 mL.

[0028] In one embodiment, in step a, if the oil-water mixture of the sample is a stable emulsion, a nonionic demulsifier can be added first, stirred, and allowed to stand for a period of time before adding a nonpolar solvent. Specifically, 5 mL of nonionic demulsifier can be added first, stirred, allowed to stand for 60 min, and then 5 mL of nonpolar solvent can be added. Here, the nonionic demulsifier can be a polyoxyethylene-polyoxypropylene block copolymer or a fatty alcohol polyoxyethylene ether.

[0029] In one embodiment, the mixing ratio of the non-polar solvent and the sample in step a can be adjusted for oil samples of different viscosities. For marine gear oil and hydraulic oil with higher viscosity, the amount of non-polar solvent added can be appropriately increased to ensure that the oil is fully dispersed in the non-polar solvent, thereby improving the effect of subsequent oil-water separation.

[0030] In one embodiment, the water volume adaptation process in step c can be flexibly adjusted according to actual testing needs. In addition to volume adaptation, the adaptation process can also be optimized in combination with the accuracy requirements of the testing instrument to further improve the applicability of the tested water sample.

[0031] In this embodiment, in step b, the centrifugation speed is 2500 r / min to 3500 r / min, and the centrifugation time is 3 min to 8 min. By limiting the specific range of centrifugation speed and time, this embodiment ensures that the oil and water in the sample mixture are fully and quickly separated, avoiding problems such as incomplete separation and blurred stratification boundaries caused by improper centrifugation parameters. This, in turn, ensures the accuracy of subsequent aqueous phase volume measurement and the cleanliness of the tested water sample.

[0032] In actual operation, the parameters can be flexibly adjusted within the above range according to the specific conditions of the oil sample, such as viscosity and water content. This takes into account the detection needs of different types of oil samples, improves the versatility and stability of the method for detecting water salinity in oil, avoids the fluctuation of detection results caused by the problem of centrifugation parameter settings in traditional detection, and effectively improves the reliability of the detection method.

[0033] Specifically, for marine lubricating oils with low water content and high viscosity, the centrifugation speed can be appropriately increased to 3000r / min-3500r / min, and the centrifugation time extended to 5min-8min to ensure thorough oil-water separation.

[0034] Specifically, for diesel fuel with relatively high water content and low viscosity, the centrifugation speed can be appropriately reduced to 2500r / min-3000r / min, and the centrifugation time can be shortened to 3min-5min. This can improve detection efficiency while ensuring separation effect.

[0035] In one embodiment, within the allowable range of the centrifuge equipment, a gradient centrifugation program can be set, first centrifuging at a low centrifugation speed of 2500 r / min for 2 min, and then centrifuging at a high centrifugation speed of 3500 r / min for 3 min. This can avoid water phase splashing caused by direct centrifugation at high speed and ensure thorough separation.

[0036] In one embodiment, step d can be performed using a micropipette, capillary tube, or pipette to aspirate the water sample. In practice, the appropriate sampling tool can be selected based on the volume of the water sample. When the sample volume is small, a capillary tube or micropipette can be used to ensure accurate aspiration of the entire sample, avoiding detection errors caused by insufficient sampling. When the sample volume is sufficient, a pipette can be used to improve sampling efficiency while ensuring the accuracy of the sample volume. It is also important to note that after sampling, the water sample should be slowly dropped onto the refracting prism of the seawater salinity analyzer to avoid splashing or uneven dripping that could affect the detection results.

[0037] Optionally, the sampling tools can be cleaned before sampling to avoid residual impurities or moisture affecting the purity of the water sample.

[0038] Optionally, for water samples with high viscosity, the sampling tool can be preheated to reduce water sample residue on the inner wall of the tool and further improve the accuracy of sampling.

[0039] Optionally, a graduated micro-sampling tool can be used to facilitate control of the sampling amount, ensure consistency of the sampling amount each time, reduce errors in batch testing, and improve the repeatability of test results.

[0040] In one embodiment, in step d, when the salinity concentration in the tested water sample is not less than 3‰, the tested water sample is determined to be seawater. When the salinity concentration in the tested water sample is less than 1‰, the tested water sample is determined to be freshwater. This embodiment clarifies the criteria for distinguishing between seawater and freshwater, making the determination of seawater and freshwater clearer and effectively avoiding misjudgments near the critical value.

[0041] In one embodiment, the oil sample is marine equipment lubricating oil, hydraulic oil, gear oil, or diesel oil. This embodiment allows for flexible adjustments to the testing details based on the characteristics of different types of oil samples, ensuring that the salinity detection method for water in oil is adaptable to various marine oil samples, achieving efficient and accurate testing, and providing reliable technical support for the operation and maintenance of various marine equipment systems. As an optional embodiment, for marine engine lubricating oil, impurities such as metal abrasive particles can be removed from the sample before mixing and sampling. As another optional embodiment, for diesel oil samples, the proportion of non-polar solvent added can be appropriately adjusted to ensure the adaptability of the testing procedure.

[0042] Figure 2 This is a block diagram illustrating a method for detecting the salinity of water in oil according to another embodiment of this application. Figure 2 As shown, after performing step b, it is necessary to perform water volume adjustment based on the volume of the aqueous phase separated from the sample mixture. This specifically includes: Step c1, if the volume of the aqueous phase separated from the sample mixture is less than 0.2 mL.

[0043] Step c2: When the volume of the aqueous phase separated from the sample mixture is greater than 0.1 mL and less than 0.2 mL, remove the upper layer of the non-polar solvent and oil mixture from the sample mixture. Add the oil sample and non-polar solvent to the remaining sample mixture and mix well. Repeat step b until the volume of the aqueous phase separated from the sample mixture is not less than 0.2 mL. Then continue to step d.

[0044] This embodiment effectively solves the problem of ineffective detection of intermediate-volume aqueous phases by gradually accumulating the aqueous phase volume until the detection requirements are met. Removing the mixture of the upper non-polar solvent and oil prevents oil impurities from contaminating the aqueous phase, ensuring the cleanliness of the water sample for subsequent testing and improving detection accuracy. This embodiment improves the adaptability and practicality of the salinity detection method for water in oil by perfecting the water volume adaptation process.

[0045] In another embodiment, after performing step b, it is necessary to perform water volume adaptation processing based on the volume of the aqueous phase separated from the sample mixture, specifically including: Step c1, if the volume of the aqueous phase separated from the sample mixture is less than 0.2 mL.

[0046] Step c3: When the volume of the aqueous phase separated from the sample mixture is no greater than 0.1 mL, add 0.1 mL of pure water to the sample mixture and mix well. Then, repeat step b to obtain a diluted water sample suitable for detection. Here, the pure water is thoroughly mixed with the sample mixture to ensure uniform fusion of the pure water and the aqueous phase. Then, step b is repeated, and the oil and water are separated again by centrifugation and settling. Finally, a diluted water sample suitable for detection is obtained. The volume of this diluted water sample meets the detection requirements of the instrument and can be used for subsequent salt concentration detection.

[0047] This embodiment achieves rapid and detectable diluted water samples by adding pure water, effectively solving the problem of undetectable trace amounts of aqueous phase. Further centrifugation and settling after adding pure water further separates oil impurities, ensuring the cleanliness of the diluted water sample and preventing oil residue from affecting test results. The entire dilution process is simple and quick, requiring no complex operations, adaptable to rapid on-site testing needs, and can cover processing scenarios with different aqueous phase volumes, improving the method's adaptability and practicality.

[0048] Furthermore, the purified water is deionized water, which effectively avoids interference from trace amounts of salt and impurities that may be present in ordinary purified water, ensuring the purity of the diluted water sample and thus guaranteeing the accuracy and reliability of subsequent salt concentration detection. This solves the problem of detection deviation caused by insufficient purity of purified water. Deionized water is readily available, low in cost, and suitable for the reagent needs of on-site testing, eliminating the need for additional complex purified water treatment processes.

[0049] Furthermore, based on the salt concentration obtained from the diluted water sample, multiplied by the corresponding dilution factor, the salt concentration of the tested water sample is calculated. Here, a seawater salinity meter is used to detect the salt concentration of the diluted water sample. The detected salt concentration value is multiplied by the corresponding dilution factor, and through a simple multiplication operation, the salt concentration of the tested water sample obtained in step c is calculated. Then, based on this calculated salt concentration, it is determined whether the original water phase is seawater or freshwater. It should be noted that the dilution factor can be calculated based on the volume of added deionized water and the volume of the original water phase. For example, if the original water phase volume is 0.1 mL and 0.1 mL of deionized water is added, then the dilution factor is 2.

[0050] This embodiment clarifies the conversion method for salt concentration in diluted water samples. Through simple multiple conversion, the true salt concentration of the tested water sample can be accurately restored, solving the problem of inconsistency between the detected value and the true value caused by the dilution operation, and ensuring the accuracy of the test results in low water volume scenarios. At the same time, the conversion method is simple and convenient to operate, requiring no complicated calculation tools, and can be completed quickly without affecting the overall testing efficiency.

[0051] In one embodiment, step d can be performed using a micropipette, capillary tube, or pipette to aspirate the water sample. In practice, the appropriate sampling tool can be selected based on the volume of the water sample. When the sample volume is small, a capillary tube or micropipette can be used to ensure accurate aspiration of the entire sample, avoiding detection errors caused by insufficient sampling. When the sample volume is sufficient, a pipette can be used to improve sampling efficiency while ensuring the accuracy of the sample volume. It is also important to note that after sampling, the water sample should be slowly dropped onto the refracting prism of the seawater salinity analyzer to avoid splashing or uneven dripping that could affect the detection results.

[0052] Optionally, the sampling tools can be cleaned before sampling to avoid residual impurities or moisture affecting the purity of the water sample.

[0053] Optionally, for water samples with high viscosity, the sampling tool can be preheated to reduce water sample residue on the inner wall of the tool and further improve the accuracy of sampling.

[0054] Optionally, a graduated micro-sampling tool can be used to facilitate control of the sampling amount, ensure consistency of the sampling amount each time, reduce errors in batch testing, and improve the repeatability of test results.

[0055] In one embodiment, in step d, when the salinity concentration in the tested water sample is not less than 3‰, the tested water sample is determined to be seawater. When the salinity concentration in the tested water sample is less than 1‰, the tested water sample is determined to be freshwater. This embodiment clarifies the criteria for distinguishing between seawater and freshwater, making the determination of seawater and freshwater clearer and effectively avoiding misjudgments near the critical value.

[0056] In one embodiment, the oil sample is marine equipment lubricating oil, hydraulic oil, gear oil, or diesel oil. This embodiment allows for flexible adjustments to the testing details based on the characteristics of different types of oil samples, ensuring that the salinity detection method for water in oil is adaptable to various marine oil samples, achieving efficient and accurate testing, and providing reliable technical support for the operation and maintenance of various marine equipment systems. As an optional embodiment, for marine engine lubricating oil, impurities such as metal abrasive particles can be removed from the sample before mixing and sampling. As another optional embodiment, for diesel oil samples, the proportion of non-polar solvent added can be appropriately adjusted to ensure the adaptability of the testing procedure.

[0057] In the description herein, it should be understood that the terms "upper," "lower," "left," "right," and other orientations or positional relationships are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used merely for descriptive distinction and have no special meaning.

[0058] In the description of this specification, references to terms such as "an embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0059] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0060] The technical principles of this application have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of this application without inventive effort, and these embodiments will all fall within the scope of protection of this application.

Claims

1. A method for detecting the salinity of water in oil, characterized in that, include: Step a: After mixing the oil sample, measure the sample, add a non-polar solvent to the sample and mix evenly to obtain the sample mixture. Step b: Centrifuge the sample mixture, and after standing, separate the oil and water in the sample mixture. Obtain a mixture of non-polar solvent and oil in the upper layer of the sample mixture, and obtain an aqueous phase in the lower layer of the sample mixture. Step c: Based on the volume of the aqueous phase separated from the sample mixture, perform water volume adaptation processing to obtain the test water sample; Step d: Take a drop of water sample and place it on the refracting prism of the seawater salinity analyzer to obtain the salt concentration in the water sample. Then, determine whether the water sample is seawater or freshwater based on the salt concentration.

2. The method for detecting the salinity of water in oil according to claim 1, characterized in that, In step b, the centrifugation speed is 2500 r / min to 3500 r / min, and the centrifugation time is 3 min to 8 min.

3. The method for detecting the salinity of water in oil according to claim 1, characterized in that, Step c includes: When the volume of the aqueous phase separated from the sample mixture is greater than 0.1 mL and less than 0.2 mL, remove the upper layer of the non-polar solvent and oil mixture from the sample mixture, add the oil sample and non-polar solvent to the remaining sample mixture and mix well, then repeat step b until the volume of the aqueous phase separated from the sample mixture is not less than 0.2 mL.

4. The method for detecting the salinity of water in oil according to claim 1, characterized in that, Step c includes: When the volume of the aqueous phase separated from the sample mixture is not greater than 0.1 mL, add 0.1 mL of pure water to the sample mixture and mix well, then repeat step b to obtain a diluted water sample that can be used for detection.

5. The method for detecting the salinity of water in oil according to claim 4, characterized in that, The pure water is deionized water.

6. The method for detecting the salinity of water in oil according to claim 4, characterized in that, The salt concentration of the tested water sample is calculated by multiplying the salt concentration obtained from the diluted water sample by the dilution factor corresponding to the diluted water sample.

7. The method for detecting the salinity of water in oil according to claim 1, characterized in that, In step d, the water sample to be tested is drawn using a micropipette, capillary tube, or pipette.

8. The method for detecting the salinity of water in oil according to claim 1, characterized in that, In step d, when the salt concentration in the water sample is not less than 3‰, the water sample is determined to be seawater; when the salt concentration in the water sample is less than 1‰, the water sample is determined to be freshwater.

9. The method for detecting the salinity of water in oil according to claim 1, characterized in that, The nonpolar solvent is xylene or n-hexane.

10. The method for detecting the salinity of water in oil according to claim 1, characterized in that, The oil sample was a marine equipment lubricating oil, hydraulic oil, gear oil, or diesel oil.

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