Moisture Content Of Oil Research Articles

Highly sensitive and chemically resistant moisture sensor based on polyether sulfone and polyimide composite membrane for power transformer oil

Abstract Moisture is the primary factor leading to the deterioration of transformer oil. Real-time detection of transformer oil moisture content holds significant importance to help power companies monitor the transformer’s operational status, track the change curve of the oil moisture content, identify water ingress causes, and implement preventive measures. However, transformer oil has the characteristics of low moisture content and complex chemical composition, which pose a substantial challenge for sensor monitoring, and require the prepared sensor to be chemically resistant and highly sensitive to moisture. To address these challenges, in this paper, a parallel plate oil moisture sensor with high sensitivity and high chemical resistance based on PES and PI was developed using the MEMS process. The sensor incorporates PES as the chemical resistance layer and PI as the moisture sensitivity layer. The parallel plate design not only optimizes sensitivity by effectively utilizing electric field lines but also allows the passage of water while isolating oil molecules, further enhancing the chemical resistance of the sensor. Experimental results in air demonstrate that the prototype sensor exhibits high sensitivity (~1.26 pF/% RH) across the full humidity range of 0-100% RH. Moreover, the sensor can withstand exposure to a wide range of chemical corrosive gases, including acetone, ammonia, etc. Tests in transformer oil reveal that the sensor has a resolution better than 200 ppm and can effectively measure moisture in the range of 0-1400 ppm, demonstrating very high sensitivity (4 pF/100 ppm) and rapid response (10/23 s).

Design of crude oil water content measuring chip based on RF method

Based on the measurement principle of RF method, a crude oil moisture content detect chip is designed with 180 nm CMOS technology. All crude oil water content detect circuits are integrated on a chip for the first time. The chip can realize capacitance measurement in the range of 50–3000 pF, the maximum output current reaches 22 mA, and the maximum current span is less than 0.062 mA. The test results of the crude oil water content measurement system built based on the chip show that the water content test results have high linearity, with the maximum output current span of 1.09 mA. With the help of modern numerical calculation methods, the actual water content in crude oil can be accurately obtained by parameter calibration of the measured value. The inherent shortcomings of the detection circuit built with discrete components are solved, which means that the detection circuit of crude oil water content has fewer components, smaller size, and higher detection accuracy.

Exploring the effects of water content on friction behavior and mechanism of DLC films in oil production environment based on molecular dynamics simulation and first-principles calculations

To provide atomic-level insights for improving the service life of the Sucker Rod Production System (SRPS) in the harsh oil extraction environment, we attempted to investigate the friction and wear behavior of the FeFe model (conventional steel plunger pump barrel) and the DLC-Fe model (DLC-coated plunger pump barrel) in the oil extraction environment through molecular dynamics (MD) simulations and first-principles calculations. The results show that the interaction force between the conventional steel plunger and the light oil chain increases significantly as the crude oil moisture content increases. The shear strain of friction layer is intensified, severely limiting its wear resistance in the harsh oil extraction environment. Interestingly, due to the weaker interaction with the light oil chain, the plunger-pump barrel system coated with DLC films exhibited excellent frictional performance. Further studies showed that the passivation of C-suspension bonds on the films surface in the crude oil effectively improved the shear resistance of the DLC friction layer with the increase of water molecules. The related results provide a theoretical support for the practical engineering application of DLC film on the surface of oil well pump plunger.

Exploration of the Relationship Between Tyndall Effect and Moisture Content in Transformer Oil

Moisture content in oil detection technology such as offline method and online monitoring method has several shortcomings. In this paper, the Tyndall effect of moisture content in transformer oil was excited by a laser with a wavelength of 633 nm, and the relationship between Tyndall effect and moisture content in transformer oil was investigated. The relationship between the grayscale of laser beam column and particles in oil and the relationship between the grayscale of laser beam column and temperature are also investigated. It was found that withstand voltage of the oil was negatively correlated with the gray pixel statistics of the light column, while the micro water content was positively correlated with the pixel statistics of the light column. The attenuation of the light column is only related to particle size. When the micro water content is below 10 ppm, the light column will have a significant brightening process with the increase of temperature, but it will gradually slow down above 10 ppm. The statistical value of gray pixels and the proportion of gray intervals can be used to moisture content determination. This method provides a new direction for the insulation performance detection technology of transformer oil.

Investigation of electrical breakdown and heat transfer properties of coconut oil-based nanofluids

This paper presents the evaluation of two grades of coconut oil - RBD (refined, bleached, and deodorized) and virgin coconut oil, plus MIDEL eN1215 as standard natural ester, by dispersing Zinc oxide (ZnO) nanoparticles to improve their breakdown strength and cooling properties. It is shown that a stable nanofluid can be realized at different concentrations of ZnO nanoparticles with or without Oleic acid as a surfactant depending upon the moisture content in oil. Dry and wet nanofluids at 1 and 0.04–0.05 wt% nanoparticles concentration, respectively, showed increased AC breakdown voltage w.r.t individual base oils. As the temperature is raised to 85 °C, the increase in AC breakdown voltage has been insignificant except for wet oils, wherein the AC breakdown voltage increases by 20–36 %. RBD coconut oil shows better viscosity and heat transfer properties, and the latter enhances further by the addition of ZnO nanoparticles. Further, the resistance to thermal aging of various nanofluids at optimum wt% of nanoparticles in terms of various physical (viscosity, pour point, flash point) and electrical properties (resistivity, dissipation factor, AC breakdown voltage) have also been analyzed and discussed.

On the Feasibility of Monitoring Power Transformer's Winding Vibration and Temperature along with Moisture in Oil Using Optical Sensors.

Despite major progress in the design of power transformers, the Achilles' heel remains the insulation system, which is affected by various parameters including moisture, heat, and vibrations. These important machines require extreme reliability to guarantee electricity distribution to end users. In this contribution, a fiber optic sensor (FOS), consisting of a Fabry-Perot cavity made up of two identical fiber Bragg gratings (FBGs), is proposed, to monitor the temperature and vibration of power transformer windings. A phase shifted gratings recoated sensor, with multilayers of polyimide films, is used to monitor the moisture content in oil. The feasibility is investigated using an experimental laboratory transformer model, especially fabricated for this application. The moisture contents are well correlated with those measured by a Karl Fisher titrator, while the values of temperature compare well with those recorded from thermocouples. It is also shown that the sensors can be used to concurrently detect vibration, as assessed by sensitivity to the loading current. The possibility of dynamically measuring humidity, vibrations, and temperatures right next to the winding, appears to be a new insight that was previously unavailable. This approach, with its triple ability, can help to reduce the required number of sensors and therefore simplify the wiring layout.

Yield and Physicochemical Properties of Marula (Sclerocarya birrea) Seed Oils among Nine International Provenances Tested in Malawi

Sclerocarya birrea (Marula) is an indigenous fruit tree that is revered for its numerous socioeconomic contributions to human livelihood. Among others, the species is an important source of seed oil that is utilized in various domestic and industrial applications. This study was carried out to assess the yield and physicochemical properties of seed oils among nine international provenances of Sclerocarya birrea (subspecies caffra and birrea) planted in Malawi. Seed oils were obtained using the Soxhlet extraction method while quality parameters were determined using procedures described by the Malawi Bureau of Standards. Oil yield was highest (52.2%) in subspecies birrea (Missira provenance; Mali). Oil moisture content, free fatty acids, acid value, and peroxide value ranged from 0.06 to 076%, 1.96 to 4.07%, 3.91 to 8.13 mg·KOH/g, and 1.84 to 5.15 meq·KOH/g, respectively. Variations in oil yield and physicochemical properties could be attributed to genetic differences and the origin of genotypes. The selection of Sclerocarya birrea for oil production and use should be based on both provenance and subspecies levels. Further studies should study the heritability of the oil content and its physicochemical properties before conclusive decisions on the use of seed for propagation are carried out.

Assessment of the Moisture Content of Oil–Paper Insulation Based on the Nonlinear Coefficient of Low-Frequency – Per-Unit Curve

Moisture is one of the critical factors that lead to the deterioration of the insulation of oil-immersed power transformers. This study develops a novel feature parameter called nonlinear coefficient <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\alpha $ </tex-math></inline-formula> of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${U}$ </tex-math></inline-formula> – <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}$ </tex-math></inline-formula> per-unit curve to assess the moisture content in transformer insulation. Results reveal that the nonlinear coefficient <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\alpha $ </tex-math></inline-formula> of oil-impregnated paperboard increases with the increase in moisture content or the decrease in excitation frequency. A power function relationship exists between <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\alpha $ </tex-math></inline-formula> and moisture content at a given excitation frequency and is minimally affected by insulation structure and degree of polymerization (DP). The validity of the new characteristic parameters proposed in this study is also verified using a model transformer in a laboratory and a real transformer in the field.

Comparative studies on phenolic, anti-oxidative, biochemical and GC–MS analysis of crude and refined edible oils

Fats and oils play a very important role in everyday life. Many oils are available in the market with potential health benefits. Some of these oils if taken in excess are harmful too. Oils can be saturated or unsaturated depending on the nature of fatty acid present in them. The current study was carried out to compare the biological activity of refined and crude oils to understand and analyze their physiochemical analysis and quantitative properties of oils. Three types of oils were selected in this project which are sunflower oil, almond oil and sesame oil. The seeds of the oils were obtained from the local market and the oil were extracted using the Soxhlet extraction method. Three refined oils of the same variety were obtained from the market. Different analytical procedures like measuring the moisture content of oils, total phenolic activity of oils, anti-oxidative properties of oils, iodine number, saponification number of oils, Reichert meisel number, total sterol content, Gas chromatography mass spectroscopy(GC–MS) analysis was performed on all categories of oils. The main purpose of this analysis is to suggest which of the oils crude or refined are good for health and metabolism. From the studies carried out and the results obtained, it was found that the crude oils of all the three varieties have more health benefits than the refined oils.

Measurement system of ultra‐low moisture content in oil based on the microwave transmission method

AbstractAs an important index of industrial oil, moisture content affects the performance of oil. With the increase of requirement to the oil quality, the measurement of ultra‐low moisture content is gradually concerned. To achieve nondestructive measurement of the moisture content in oil, this paper analyzes the principle of dielectric loss of oil‐water mixture and proposes a measurement system based on the microwave transmission method. The hardware of the system, horn antenna, and experimental device were designed and built. The system uses a subtracter circuit together with a high‐performance microwave chip and high‐precision analog‐to‐digital converter to detect 1dB microwave attenuation. The results showed that the system can measure the moisture content of 0.01%–0.8% in quenching oil and the single detection absolute error is less than ±0.05%, and the average detection absolute error of 10 detections is less than ±0.02%. This study is useful for nondestructive detection of the moisture content in oil and provides a reference for related product development.

Effects of Sweet Potato Powder Selected Based on the Polar Paradox Hypothesis on Oil Oxidation in the Preparation of Deep-Fried Croquettes.

This study investigated whether sweet potato powder (SPP) and purple SPP (PSPP) could prevent oil oxidation during deep-frying. A volume of soybean oil was repetitively used for deep-frying croquettes coated with either SPP or PSPP. An aliquot of the fried oil was collected (SPP and PSPP oils) before and after each frying to analyze moisture and lipid oxidation products (LOPs). With increasing numbers of frying, the moisture content in oils significantly increased without an appreciable difference between SPP and PSPP oils. The total oxidation values reflecting primary and secondary LOPs also significantly increased. However, the values were higher for PSPP oils despite the much higher antioxidant activity of the polar extracts from PSPP compared to SPP. This was attributed to the presence of transition metals. PSPP oils seemed to have association colloids whose interfaces were occupied more with polar antioxidants, thereby transition metals were easily reduced and their pro-oxidative activity increased. The polar paradox hypothesis stating that polar antioxidants are more effective in preventing lipid oxidation in bulk oil is not always applicable to real foods due to various food matrices.

Microbiological Quality and Organoleptic Property of Meat and Fish Preserved with Oil from Dacryodes Edulis Seed

Abstract The bioactive compounds contributing to aroma and natural antimicrobial potential of oil from Dacryodes edulis seed can be harnessed in food industries as food preservatives. This study therefore, reveals the preservative effect and organoleptic property of meat and fish preserved with oil from D. edulis seed. Proximate and mineral analysis of oil were carried out using standard methods. Preservative quality of oil on fish and meat was investigated at 4°C and 37°C. Organoleptic property of preserved fish and meat was determined using trained panellists. Fat, protein, carbohydrates, crude fibre, ash and moisture content of oil from D. edulis seed are 55.7%, 18.7%, 10.8%, 7.1%, 4.6% and 3.1%, respectively. Potassium (106.5 µg/g) and phosphorous (102.5 µg/g) have the relatively highest values compared (p&lt;0.05) to other minerals like zinc, iron, calcium, magnesium, and sodium. Better preservative property of oil was observed on fried fish and meat kept at 4°C with no microbial growth. The highest microbial load (3.95 × 106 cfu/g) occurred in fresh chicken coated with oil from D. edulis seed after 7 days of preservation. Fish and meat fried with oil from D. edulis seed were well accepted (9.00) than those fried with groundnut oil (3.50). Oil from D. edulis seed is an edible oil that can be utilized as alternative vegetable oil with natural preservatives and embedded nutrients.

Moisture Content and Aromatic Compounds Determination in Transformer Oil Using Spectral Method

During operation, resulting from the thermochemical and electrical effects, the performance of the transformer oil decreases due to the measurement of the structural group composition. An increase in the content of the aromatic hydrocarbons leads to the appearance of a precipitate, and as well as due to its hygroscopicity, an increase in the moisture content. The latter is one of the transformer oil parameters that determines its quality. In power equipment, the presence of moisture of the order of 10 grams of water per ton of oil is allowed. At elevated water concentrations, there is a risk of the power transformers’ failure. The aim of the work was to develop new methods for determining the aromatic compounds and water contents in the transformer oil in small quantities. This goal was achieved by conducting spectral studies of the transformer oil samples in the UV range and constructing correlation lines to determine the moisture content and concentration of aromatic compounds. The most significant result of the article was the establishment of correlations between the optical density of the transformer oil in the region of 530 nm and the concentration of aromatic compounds and between the optical density in the region of 980 nm and moisture content in the oil. The significance of the obtained results lies in the fact that the optical method for determining the moisture content and aromatic hydrocarbons in transformer oils, using the constructed correlation lines, is highly accurate and does not require the use of additional reagents and complex calculations.

Temperature Compensation of Frequency Domain Spectroscopy Measurement for Condition Assessment of Oil-Paper Insulation

This article proposes a novel method for predicting frequency-domain spectroscopy (FDS) characteristics of oil–paper insulation at a temperature, which is different from the measurement temperature, through estimating activation energy. The predicted FDS characteristics curves at different temperatures show a very good agreement with each other when compared to the experimentally measured characteristics. From the FDS characteristics, two moisture-sensitive parameters are proposed for accurate estimation of moisture content of oil–paper insulation. The proposed technique is experimentally validated on several test samples with different moisture contents and also on a real-life transformer.

A study on the characteristics of Watercut Meter ultrasonic data according to the temperature change of the introduced material

Recently, for the extraction of unconventional petroleum resources, the SAGD (Steam-Assisted Gravity Drainage) method, which uses high-temperature steam to reduce the viscosity of bitumen, is widely used. In particular, the importance of the Watercut meter system is increasing because the oil sand mining technology is an additional and more complicated process than oil extraction in general oil wells. In this study, a numerical analysis of the ultrasonic-based SOR (steam to oil ratio) ratio change for heavy oil was performed. As a result of the analysis, the maximum sound pressure and the ultrasonic arrival time were analyzed using the SOR ratio as a variable. The higher the water-to-oil ratio, the higher the maximum sound pressure and the shorter the ultrasonic arrival time. On the other hand, the higher the oil ratio, the lower the maximum sound pressure and the longer the ultrasonic arrival time. It is judged that the data set on the moisture content in oil can be constructed using the numerical analysis results, and it can be used as a basis for the reverse engineering of Watercut.

Effect of Concentration of Al2O3 Nanoparticles on Electrical Properties of Mineral Oil

This study aimed to compare the electrical characteristics of mineral oil-based nanoparticles to those of pure mineral oil. Mineral oil used in distribution transformers was mixed with aluminum oxide (Al2O3) nanoparticles, which serve as an insulator, with 0.01, 0.03, and 0.05 % mineral oil volume concentrations. The moisture content in mineral oil was measured beforehand, and the electrical tests were subsequently conducted in accordance with international standards. The moisture content test revealed that the combination of nanoparticles and mineral oil resulted in an increase in moisture content. As regards the test of AC withstanding voltage and negative polarity lightning impulse voltage, it was found that the mineral oil mixed with the nanoparticles had higher dielectric strength than the original mineral oil. In addition, the test results of positive polarity lightning impulse voltage demonstrated that with a mixture of mineral oil and the nanoparticles at a 0.01 % concentration, the positive polarity lightning impulse dielectric strength of the mineral oil increased. However, at concentrations of 0.03 and 0.05 %, it did not rise, regardless of the increasing volume of nanoparticles. The results, thus, showed promising directions for applications of nanoparticles in the development of electrical properties of mineral oil. HIGHLIGHTS The addition of Al2O3 nanoparticles to the mineral oil resulted in an increase in the oil moisture content. However, it was found that the moisture content in the mineral oil tended to decrease with the increase in the amount of nanoparticles The optimum nanofluid combination in terms of increased AC breakdown strength was created by adding Al2O3 nanoparticles to mineral oil at a rate of 0.05 vol% The Al2O3 nanoparticles being added to the mineral oil can give an increase in the impulse breakdown voltage with the negative polarity For the positive polarity of the impulse breakdown voltage, the best nanofluid mixture in terms of increased breakdown strength was produced by the addition of Al2O3 nanoparticles at a rate of 0.01 vol% to the mineral oil GRAPHICAL ABSTRACT

Effect of DC electric field on moisture migration characteristics in oil‐pressboard

The moisture content has a great influence on the electric insulation strength of oil-pressboard. Therefore, it is very important to assess the moisture content in power transformers. There is lack of research about the effect of DC electric field on moisture migration. Here, the authors analyse the moisture migration characteristics of oil-pressboard under DC electric field. The DC electric field has a greater influence on the moisture content in the oil. Compared with no DC electric field, the moisture content in oil is reduced by 22.91 mg/L at 50°C, while it is reduced by 17.63 mg/L at 70°C. Under the same moisture content in the oil, the moisture content in the pressboard which affected by the DC electric field is higher than the Oommen curve, the maximum difference is 0.88% at 50°C, and 0.05% at 70°C. This result can provide a reference for the revision of existing moisture assessment methods.

Effects of Moisture and Amphiphilic Compounds on the Oxidative Stability of Microwave‐Treated Corn Oil

AbstractEffects of moisture and amphiphilic compounds, including oleic acid, lecithin, and monoacylglycerols (MAGs), on the oxidative stability are evaluated in microwave‐treated corn oil. Moreover, the physical properties including critical micelle concentration (CMC) and moisture content are determined in oils treated by microwave irradiation. The CMC of lecithin and moisture content of oils decreases remarkably, whereas the temperature of the oil increases rapidly with microwave irradiation. The addition of lecithin results in increased moisture content significantly in the edible oils, whereas oleic acid and MAGs do not exhibit these effects. Primary oxidation products in all the oil samples increase, despite the type of amphiphilic compounds used. Corn oil containing oleic acid and samples with lecithin exhibits lower and higher p‐anisidine values (p‐AV), respectively. Remarkably high moisture content in corn oils containing lecithin may contribute to the formation of volatile compounds and high p‐AV. Collectively, moisture and amphiphilic compounds affect the degree of lipid oxidation in microwave‐irradiated bulk oils.Practical application: A microwave oven is an irreplaceable home appliance and is widely used in households nowadays. Effects of amphiphilic compounds and moisture on the oxidative stability are evaluated and it is found that the amphiphilic compounds in lipids affect heat transfer and oxidative stability of oils. The results of this study can provide fundamental insights into lipid oxidation in edible oils, and can provide a direction to the food industry with respect to the development of more efficient and safe methods for the preparation of microwavable foods.

Transformer Oil Diagnosis Based on a Capacitive Sensor Frequency Response Analysis

Condition monitoring of large power transformers is of paramount importance in power systems. One of the most common indicators of transformer aging is moisture content in oil. In this article, a capacitive sensor able to online measuring moisture content is presented. The output of this sensor is recorded using a Frequency Response Analysis (FRA) device. Comparing the FRA results of a degraded oil with a reference FRA test, moisture content can be determined. A prototype sensor has been designed, built and tested. The performance of this sensor was simulated and laboratory tested with different moisture content oil samples. The results confirm that the proposed sensor can determine moisture content in oil. Therefore, it allows estimating oil degradation.

Error Correction Method of Crude Oil Moisture Content Detection Based on BP Neural Network

Microwave phase-shifting sensor is one of the effective means to realize online detection of water content in high water-cut crude oil, but its detection accuracy is easily affected by salinity. Aiming at the mineralization components (NaCl and CaCl2) existing in water-bearing crude oil, the influence of different proportion and content of dual-component mineralization on the accuracy of microwave phase-shifting crude oil water content detection sensor was studied experimentally, and the influence rule of dual-component mineralization (NaCl and CaCl2) on the accuracy of crude oil water content detection was obtained. It is difficult to establish an accurate error compensation model because the relationship between the composition and content of salinity and the measured water content is affected by many factors. Therefore, a BP neural network model for error correction is established, which reduces the detection error of microwave phase-shifting crude oil moisture sensor from 13.912% to 1.821%, and improves the detection accuracy. BP neural network prediction model is superior to multiple linear regression prediction model.