Acid Number Of Oil Research Articles

The Effect of Water Content on Engine Oil Monitoring Based on Physical and Chemical Indicators.

Engine oil oxidation is one of the major reasons for oil aging which can result in variations in the physical and chemical properties of oil. Organic acids generated by oil oxidation can react with water to form inorganic acids and acidic substances (including organic and inorganic acids) that corrode engine parts, resulting in the generation of rust or damage to engine parts. This is one of the important reasons why oil should be regularly changed. One of the most commonly applied methods for judging the aging degree of engine oil is monitoring its acid number (AN). However, generally, the effect of oil water content on acid value measurement is not considered. When oils are used in engines, they are often contaminated by water due to condensation, which accelerates engine oil aging. Therefore, it is crucial to explore the water content effect on AN in the process of engine oil aging. In this research, a water content sensor was applied to characterize moisture content in oxidized oil samples. The sensor could also obtain oil sample electrical conductivity which corresponded to its dielectric constant. Using a mid-infrared spectrometer to measure oil sample AN at this point to obtain the variation in AN with oxidation time, oil sample AN was connected in series with the water content, dielectric constant and electrical conductivity. These parameters were monitored through sensors, and the effect of water content on AN was studied. Experimental results revealed that with the increase in oxidation time, the water content, electrical conductivity, dielectric constant increase and AN of oil were increased. At the same time, since the temperature had a greater effect on electrical conductivity, the application of an air-conditioned constant-temperature environment removed the effect of temperature change on electrical conductivity.

THE ROLE OF PLANT GROWTH REGULATORS IN THE FORMATION OF SUNFLOWER HYBRIDS PRODUCTIVITY

The results of the study of the influence of plant growth regulators and basic nutrients on the productivity of sunflower hybrids of different maturity groups are presented. The research was carried out on the basis of the farm of LLC "Organic-D" in the village of Sutisky, Vinnytsia region, during 2021-2022. The soils of the experimental plot are gray forest soils with medium loamy texture and slightly acidic reaction of the soil solution. The content of the main nutrients is typical for this type of soil. The research was conducted on three sunflower hybrids: early maturing –Oskil, mid-early - NK Delphi and mid-early - NK Condi by applying the plant growth regulator (PGR) DEFENDA Vertex (0.5 l/t) and mineral fertilizer at the rate of N45P45K45 d.p. m. The technology of sunflower cultivation is generally accepted for the conditions of the Right-Bank Forest-Steppe of Ukraine, except for the factors under study. We have found that the use of seed treatment with PPP DEFENDA Vertex and the application of mineral fertilizers at the rate of N45P45K45 on the crops of the studied sunflower hybrids of different maturity groups led to an improvement in the morphological structure of plants, an increase in their productivity, which ultimately led to an increase in oil yield per unit area. The maximum value of plant height, number of flowers and seeds in the basket of the studied hybrids in the variant with the combined application of mineral fertilizers at the rate of N45P45K45 with the treatment of seeds with PPP DEFENDA Vertex: Oskil - 163.3 cm, 1129 pcs. and 923 pcs, NC Delphi - 187.1 cm 1247 and 967 pcs. and NC Condi - 171.7 cm 1335 and 995 pcs. respectively. The highest level of yield, on average for two years of research, was obtained in the variant with the use of seed treatment with PPP DEFENDA Vertex and the application of mineral fertilizers at the rate of N45P45K45 in the sunflower hybrid Oskil - 2.78 t/ha, NC Delphi - 2.95 t/ha, mid-season NC Condi - 3.09 t/ha, which is 0.48-0.59 t/ha more compared to the control variant. Seed treatment with PPP DEFENDA Vertex provided an increase in yield of 0.27-0.36 /ha, compared to the control variant (without seed treatment and fertilization). Seed treatment with PGR DEFENDA Vertex contributed to the growth of oil content in the seeds of the studied hybrids and it was 46.9%, 49.7 and 54.5%, and the combination of seed treatment with PGR DEFENDA Vertex and the introduction of mineral fertilizers in pre-sowing cultivation provided the highest value of oil content - 47.8%, 50.1 and 55.7%, respectively. The acid number of oil had an ambiguous value when using the studied factors. The highest value of huskiness was obtained when using a combination of seed treatment with PGR DEFENDA Vertex with the introduction of mineral fertilizers in pre-sowing cultivation in the hybrid Oskil - 23.7%, NC Delphi - 26.3% and NC Condi - 24.9%. The combined use of seed treatment with PGR DEFENDA Vertex and mineral fertilizers at the rate of N45P45K45 showed the highest value of oil yield per unit area - 1.47 t/ha, 1.61 and 1.72 t/ha, respectively, in hybrids Oskil, NK Delphi and NK Condi.

РЕЗУЛЬТАТЫ ИССЛЕДОВАНИЙ ПО ОЦЕНКЕ ИЗМЕНЕНИЯ СВОЙСТВ МОТОРНОГО МАСЛА БЕЗ И С ИСПОЛЬЗОВАНИЕМ ОПЕРАЦИИ ПРОМЫВКИ СИСТЕМЫ СМАЗКИ ДВИГАТЕЛЯ ТРАКТОРА

The results of studies assessing the properties of oils for removing contaminants from the lubrication system during routine replacement of motor oils in tractor engines are presented. It has been established that when used motor oil is drained, some of the contaminants remain in the lubrication system and negatively affect both engine operation and the service life of freshly filled motor oil. Dependences of changes in the content of mechanical impurities, tar deposits, alkaline and acid numbers on operating time were obtained. It has been established that the alkaline number of the oil during the engine operating period can decrease from 8.7 mg KOH/g to 2.0 mg KOH/g and reach the rejection value by 250 hours of oil operation in the engine. The influence of the operation of flushing the lubrication system with Lukoil mineral-based flushing oil in MTZ-1221 tractor engines is considered. The flushing operation made it possible to reduce the accumulation of impurities by 20...30% over the same operating period and to reduce the accumulation of tar deposits in the engine oil from 9.8% to 0.7%. Removing contaminants from the lubrication system reduces the consumption of additives, their waste in motor oils, and precipitation along with contaminants. For an operating period of 250 hours, the alkaline number content was 4.9 mg KOH/g, while over the same operating period without flushing the lubrication system it approached the rejection value. Removing contaminants stabilizes the change in oil acid number. In general, it is noted that carrying out the operation of flushing the lubrication system of tractor engines can improve their performance and increase the service life of the engine oil before it is replaced.

The Use of Soxhlet Techniques in the Essential Oil Extraction from Anise Seeds (Pimpinella anisum)

<strong>ABSTRACT. </strong>Anise seeds can be processed into essential oils by steam distillation and solvent extraction. This research aims to produce a high oil yield by determining the optimum conditions of extraction, extracting anise seeds according to optimum conditions, producing anise oil with good quality based on 90% alcohol solubility analysis, analyzing the acid number, and conducting GC-MS analysis. The Activity Method was carried out by determining the optimum conditions of extraction on the effect of the variation in the ratio between anise seed powder and petroleum ether. Furthermore, based on optimal conditions, extraction was carried out at a temperature of 60°C, 5 hours with 5 repetitions. The results of essential oils were analyzed including solubility analysis, oil acid number, and GC-MS. The optimal extraction conditions were obtained at the ratio of anise seeds and petroleum ether 1:12.5 with an average oil yield of 4.72%. The results of the analysis showed that anise oil had good quality based on the oil solubility in 90% alcohol with a 1:7 ratio. The acid number of anise seed oil was obtained at 1.14444. GC-MS analysis showed that anise seed oil contained estragol, anethole, limonene, fenchone, and anis ketone.

Modeling of the Phase Inversion Point of Crude Oil Emulsion by Characterization of Crude Oil Physical Properties.

Accurate prediction of the phase inversion point (PIP) of crude oil emulsion (COE) will give important guiding significance to the mixed transportation technology during the crude oil mining process. The influence of water cut of a system on viscosity characteristics of the COE was studied by emulsification experiments with 16 kinds of crude oils having significant differences in physical properties. The results showed that under the condition of low water cut of a system, the crude oils can emulsify all the water to form stable W/O emulsions with apparent viscosities much higher than those of pure crude oils. When the water cut of a system exceeds a certain critical value, the crude oils have no ability to emulsify all water; instead, they are wrapped by a water phase and form unstable O/W emulsions, and their apparent viscosities decrease sharply compared with those of pure crude oils. The critical water cut of a system corresponding to the abrupt change of apparent viscosity of the COE is the PIP of the COE changing from the type of W/O to O/W. Furthermore, the apparent viscosities of stable W/O emulsions decrease with increasing shear rate and temperature and meanwhile increase dramatically with the increasing water cut of a system. The apparent viscosities of unstable O/W emulsions decrease with increasing shear rate, water cut of a system, and temperature and are far lower than those of pure crude oils. Four typical parameters were chose as the representation to describe the crude oil physical properties (COPPs), that is, the content of saturates, the content of aromatics, the content of surfactants, and the crude oil acid number. On the basis of the quantitative description of COPPs, a prediction model for the PIP of the COE was established. The results of model verification showed that the mean relative deviation of prediction results was 2.9%.

RATIONAL DRYING MODES FOR RAPE SEEDS

Studies on finding rational regimes for drying rapeseed based on drying kinetics and qualitative characteristics are presented. The value of the acid number of oil and laboratory germination of rapeseed on the 7th day of germination were taken as a qualitative characteristic. Experimental studies of the kinetics of the rapeseed drying process were performed on a convective drying stand using an automatic program for collecting and processing information, which makes it possible to obtain more accurate experimental data. According to the obtained experimental data with the help of an automatic program for collecting and processing information, graphs of the process kinetics from the influence of the coolant temperature are constructed. The presented graphs show the drying curves and drying speed curves that characterize the drying process that takes place during the period of falling drying speed. The study of the kinetics of the drying process of rapeseed in a single-stage mode at coolant temperatures of 50 - 80°C showed that for better quality it is necessary to use low-temperature modes. The acid number of oil in this temperature range does not change significantly and is 1.03 - 1.8 mg / g of oil. These values of the acid number of the oil correspond to the normative value. The greatest effect on the germination of rapeseed is observed from the temperature of the coolant. Increasing the temperature by 10 ° C in the temperature range from 50 to 80 ° C reduces the germination of the material. According to laboratory studies, we determined the drying regime of 50 ° С with a germination of 97% to be the most expedient and rational. All other drying regimes significantly reduce the germination of rapeseed and can not be recommended, as the germination value is less than the state standard of Ukraine 2240-93.

Research on the effect of the effective microorganisms, silver solution and colloidal nanosilver addition on the engine oil acid number (TAN)

In the article, acid number as a parameter characterizing engine oil were characterized. The next part of the article discusses the phenomenon of aging and degradation of engine oil. The factors that influence on this phenomenon have also been analyzed. In the further part of the article, the methodology of testing the used oil samples with the addition of effective microorganisms and silver solution was described. In the main part of the article the measuring test stand and acid number value for fresh and used oil compared to oils with the addition of microorganisms and a solution of silver and colloidal silver was shown. Next the analysis of the influence of these additives on the acid number value was made. The article was completed conclusions.

Prediction Model between Emulsified Water Fractions and Physicochemical Properties of Crude Oil Based on the Exergy Loss Rate.

The quantitative calculation of emulsified water fractions of crude oil–water systems is of great significance for the study of flow characteristics of multiphase flow pipelines. For a crude oil–water system with a high water fraction, the emulsified water fraction under different influencing factors was determined by emulsification experiments. It was found that the emulsified water fraction under different shearing conditions correlated well with the exergy loss rate and could be described by a power-law equation, in which two undetermined parameters relate to the crude oil physicochemical properties. Six representative parameters were selected to describe the crude oil physicochemical properties, i.e., the sum of asphaltene and resin contents, wax content, mechanical impurity content, crude oil acid number, crude oil average carbon number, and crude oil viscosity. Further, the correlations between the two undetermined parameters and the crude oil physicochemical properties were derived by regression analysis. Thus, the prediction model of emulsified water fraction was determined, which could be conveniently adopted to predict the emulsified water fraction with different crude oils and shearing conditions. The validation results showed that the mean relative deviation of the model prediction is 4.5%.

Performance prediction of ion-engineered water injection (EWI) in chalk reservoirs using Response Surface Methodology (RSM)

Ion-engineered water injection (EWI) is one of the advantageous enhanced oil recovery (EOR) techniques that gained considerable attention in recent years. Many mechanisms have been proposed for additional oil recovery with modified seawater composition when injected into carbonate formations. However, the prediction of EWI is a big challenge due to complex rock/fluid interactions at pore level and related mechanisms. Thus, an efficient design method for water composition is required. This study investigates the optimization of EWI through the concentration of the active and non-active ions in injection water at laboratory scale for chalk core samples by considering the most dominant design parameters. Data from many imbibition tests of chalk core samples were selected. The Response Surface Methodology (RSM) was used to screen the significant contributing parameters. The sensitivity analysis showed that the four most important design parameters are crude oil acid number (TAN), crude oil base number (TBN), temperature, and injected water salinity. An optimum EWI design was suggested, and the predicted responses were validated using other experimental results that have not been used for model development with high accuracy. The model can be applied for experimental design and optimum water composition.

Elucidate three novel catalysts synthesized from animal bones for the production of biodiesel from ternary non-edible and edible oil blend: A case of Jatropha curcus, Hevea brasiliensis, and Elaeis guineensis oil

This study developed three activated CaO-based catalysts from chicken foot bone, catfish bone, and the mixed, employed for the synthesis of biodiesel from the blend of three (2 non-edible, 1 edible) vegetable oil. The catalysts were calcined at 1000 °C for 3 h and were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and BET isothermal adsorption. The blend of oil was achieved through the API gravity ratio, while the blended oil with high acid value was reduced with a strong acid (H2SO4). Process optimization of the reaction conditions was carried out using Central Composite Rotatable Design (CCRD) in the esterification step, while Box Behnken Experimental Design (BBED) was used in the transesterification of the esterified oil to biodiesel. The qualities of the biodiesel were determined using AOAC method.Results showed the oil blend ratio produced biodiesels of low viscosity and density. Catalysts’ characterization showed the amount of CaO-based found through XRD analysis in the catalysts was 93.52%, 91.24%, and 99.84%, respectively. Acid esterification through experimental design by CCRD produced a low blend oil acid number of 1.27 mg KOH/g oil. The maximum experimental biodiesel yields of 93.60, 92.47, and 97.12 (%wt.), but, the statistical optimization predicted values by BBED were 93.86, 92.7685, and 97.2566 (%wt.), which were validated as 93.5400, 91.87, and 96.88% (wt.), respectively, at the reaction time of 69.76 min, the catalyst amount of 4.16 g, the reaction temperature of 69.79 °C, and the CH3OH/OMR of 4.62:1. Catalyst regeneration and reusability showed that the derived catalyst has the potential to be reused in the 4th cycle. The qualities of the biodiesel were well within the limit recommended for biodiesel standard.

Seed productivity and reproduction features of Schisandra chinensis under conditions of the M.M. Gryshko National Botanical Garden

Data on seed productivity and peculiarities of reproduction of Schisandra chinensis under the conditions of introduction at the M.M. Gryshko National Botanical Garden of the National Academy of Sciences of Ukraine (NBG) are discussed. The study was carried out in 2016–2018 on experimental fields and in the NBG laboratory using plants and seeds of Ukrainian selection S. chinensis ‘Sadovyi-1’. Sections were examined with the microscope Carl Zeiss STEMI 2000-S. Qualitative and quantitative composition of higher fatty acids has been identified by НР-6890 chromatograph. It was found that S. chinensis of local reproduction have a much lower percentage of the seeds without embryo (about 10 %) compared to those of natural origin (30–90 %). Because of long-term storage of S. chinensis seeds the biochemical transformations take place: the content of fats and proteins decreased from 37.5 to 28.0 %, and from 19.7 to 11.2 %, respectively, the acid number of oil increased from 2.42 to 5.70 mg KOH/g, and its iodine value decreased from 32.5 to 30.3 g І2 / 100 g after storage of seeds during ten months. Fatty oil of S. chinensis seeds has a high linoleic acid content, which reaches 80–81.1 % of the total content of fatty acids. The storage of seeds under different illumination and temperature conditions resulted in minor changes in the acid number of the oil and the quantitative content of fatty acids. The optimal storage conditions of seeds (without access to light and at the temperature of +4 °С) were determined. Such storage conditions reduce the intensity of oxidative processes in the seeds, ensuring the highest germination rate. The optimal ways of S. chinensis reproduction by seeds are the spring sowing of stratified seeds and autumn sowing of freshly reaped seeds, which gain natural stratification. Using these ways resulted in 65 % and 63 % of seeds germination, respectively.

Очищення відпрацьованих мінеральних моторних олив кристалічним карбамідом

Під час експлуатації автотранспортного засобу мінеральна моторна олива у двигуні внутрішнього згорання (ДВЗ) піддається безперервному впливу високої температури, окиснення, термічного розкладу, зовнішніх забруднювачів, каталізаторів (продуктів зношення металевих поверхонь) тощо. Внаслідок цього в ній накопичуються продукти зношення деталей ДВЗ та розкладу присадок, продукти окиснення вуглеводневої частини, асфальто-смолисті речовини тощо, що спричиняє незворотні зміни її якісного хімічного складу. Для видалення з відпрацьованих олив оксигеновмісних продуктів старіння та зниження їхнього кислотного числа доцільно використовувати метод коагуляції. Одним з легкодоступних та перспективних коагулянтів для очищення відпрацьованих мінеральних моторних олив може слугувати кристалічний карбамід. Його додавали до відпрацьованих олив і перемішували за підвищеної температури. Контроль ефективності процесу очищення карбамідом здійснено за кислотним числом оливи. Використаний карбамід разом із виокремленими компонентами оливи відділяли фільтруванням. Встановлено оптимальні умови процесу, а саме: кількість карбаміду – 5 % мас. на сировину; температура – 140 оС; тривалість перемішування – 80 хв. Для вивчення зміни експлуатаційних властивостей очищених мінеральних моторних олив здійснено дослідження за стандартизованими методиками та за допомогою рентгенофлуоресцентного та ІЧ-спектрального методів аналізів. Встановлено, що внаслідок очищення відпрацьованих олив карбамідом їхнє кислотне число істотно зменшується, що підтверджується ІЧ-спектральним аналізом. Відбувається також незначне підвищення індексу в'язкості олив, а також зниження вмісту механічних домішок, води. Зольність олив також зменшується. Це підтверджено також результатами рентгенофлуоресцентного аналізу. Використання кристалічного карбаміду для очищення ВММО дає змогу зменшити вміст оксигеновмісних продуктів старіння, водночас, в очищеній оливі залишаються небажані поліциклічні ароматичні вуглеводні, асфальто-смолисті речовини, продукти розкладу присадок та механічні домішки, для видалення яких необхідно використовувати додаткові стадії очищення.

C.10.05 The role of patient organizations in supporting patients with schizophrenia

In situ CO2 enhanced oil recovery (ICE) has great potential for the mature oil field. ICE can deliver CO2 to the targeted formation by the injection of CO2 producing agents which decompose in the reservoir to release CO2 and other oil recovery enhancing compounds. The mechanism of the ICE system was evaluated experimentally. Alkali and hydrotrope induced interfacial tension (IFT) reduction were studied with crude oils that have different acid numbers and also dodecane. The independent and combined effect of the ICE system on wettability reversal was quantified by contact angle measurement with different fluid systems and lithology. Ten one-dimensional sand pack flooding tests with different lithology and fluid systems were designed to isolate the different recovery mechanisms and study their individual contribution to the final tertiary recovery. From the experimental results, the highest IFT reduction by alkali effect was from 21 mN/m to 0.77 mN/m. The wettability of clean sandstone and sandstone aged in crude oil were responsive to different concentrations of NH3 solution. The sandstone surface became more water-wet with increase in NH3 (aq) concentration. The wettability of carbonate core samples were not strongly affected by the NH3 solution. Both aged sandstone and carbonate core samples showed significant wettability reversal from oil-wet to water-wet after the ICE treatment. After a series of sand pack flooding tests, it was shown that the effect of CO2 was more dominant in carbonate reservoirs and NH3 (aq) contribution to the tertiary recovery increased with the increase of the crude oil acid number. The results help elucidate the mechanisms in ICE and their contribution to the final oil recovery.

Study on analysis of acid number of transformer oil by temperature titration

Important test methods for acid number of oil products were introduced, and their characters, difference and selection Principle were described. And the temperature titration method was used to determine the acid number of transformer oil. Meanwhile, several major factors that may affect the outcome were discussed.

Isolated mechanism study on in situ CO2 EOR

In situ CO2 enhanced oil recovery (ICE) has great potential for the mature oil field. ICE can deliver CO2 to the targeted formation by the injection of CO2 producing agents which decompose in the reservoir to release CO2 and other oil recovery enhancing compounds. The mechanism of the ICE system was evaluated experimentally. Alkali and hydrotrope induced interfacial tension (IFT) reduction were studied with crude oils that have different acid numbers and also dodecane. The independent and combined effect of the ICE system on wettability reversal was quantified by contact angle measurement with different fluid systems and lithology. Ten one-dimensional sand pack flooding tests with different lithology and fluid systems were designed to isolate the different recovery mechanisms and study their individual contribution to the final tertiary recovery. From the experimental results, the highest IFT reduction by alkali effect was from 21 mN/m to 0.77 mN/m. The wettability of clean sandstone and sandstone aged in crude oil were responsive to different concentrations of NH3 solution. The sandstone surface became more water-wet with increase in NH3 (aq) concentration. The wettability of carbonate core samples were not strongly affected by the NH3 solution. Both aged sandstone and carbonate core samples showed significant wettability reversal from oil-wet to water-wet after the ICE treatment. After a series of sand pack flooding tests, it was shown that the effect of CO2 was more dominant in carbonate reservoirs and NH3 (aq) contribution to the tertiary recovery increased with the increase of the crude oil acid number. The results help elucidate the mechanisms in ICE and their contribution to the final oil recovery.

Influence of metal transformer materials on oil-paper insulation after thermal aging

This study investigated the influence of the main metal materials of transformers on the oil-paper insulation performance. Ten types of insulating specimens were subjected to accelerated thermal aging at 120°C. Some aging parameters, including oil acid number, furfural content and degree of polymerization (DP) of insulating paper, were measured and compared. At the same time, we conducted frequency domain spectroscopy, X-ray diffraction, scanning electron microscopy and energy dispersive spectrometry on the insulating paper. The following conclusions were drawn: silicon lamination slightly deteriorates the insulating oil, copper increases the acidity and accelerates the production of furfural, metal materials can decrease DP of insulating paper and the effect of copper is greater than that of silicon lamination. During thermal aging, the dielectric dissipation factor of insulating paper increases and the carbon content of insulating paper increases. Metal materials can significantly increase the dielectric dissipation factor and carbon content of insulating paper and the effect of copper is greater than that of silicon lamination.

Development of methods for neutralizing the free fatty acids of fatty coriander oil

In the present paper, the information on the process of enzymatic conversion of free fatty acids in fatty coriander oil (FCO) was considered. Enzymatic esterification was performed according to the following algorithm: FCO was treated with enzymes, purified by adsorbents with a variation of the basic process parameters, alcohols of a different nature were added. The quality of the samples of the purified FCO was determined by the basic physicochemical index - acid number. Ethanol (96 %) and glycerin (99.3 %) were used as reagents. Enzyme preparations (manufactured by «Novozymes» Denmark): Novozym 435, Lipozym TL IM were used as catalysts. Using the FCO fining methods, given in the paper, it was managed to reduce the acid number of oil from 17.0 mg KOH/g to 0.3 mg KOH/g. It was proved that using vacuum is an appropriate technological stage of enzymatic esterification of the FCO. Using molecular sieves for the FCO fining to reduce the content of water formed in the esterification and, thus, improve the conditions for the conversion reaction of free fatty acids - reduced acid number to less than 2.1 mg KOH/g was investigated. It was found that when adding molecular sieves in the FCO - reagent - enzyme system, water removal is not observed and their use does not decrease the acid number of oil at all. The fatty acid composition of the sample of the initial FCO was investigated by means of gas-liquid chromatography. It was found that in the initial FCO the percentage of the main fatty acids are the following: palmitic - 2.4 %, petroselinum - 71.3 %, oleic - 7.8 %, linoleic - 15.6 %. The authors have examined the process of adsorption of free fatty acids from the esterified FCO using the anionite EDE - 10P. It was found that the increase in the ratio of FCO to the adsorbent does not result in complete removal of free fatty acids and, accordingly, sufficient decrease in the acid number of the purified oil.

Alteration of Heavy Oil Properties under In-Situ Combustion: A Field Study

A pilot test of in-situ combustion (ISC) was carried out in Jiang oil field, Junggar basin, China, and a favorable result was obtained. In this work, we systematically studied the changes of crude oil properties during the combustion process. Crude oils were characterized by means of rheology test, SARA (saturates, aromatics, resins, and asphaltenes) fractionation and analyses, CHNO elemental analyses, and acid number (AN) measurements. Furthermore, analyses of FTIR and GC-MS on the resins were carried out to investigate the functional groups and polar compounds. Moreover, influence of particular inclined formations and sampling wells’ locations are also considered to interpret the effects of ISC process in the field. During the fireflood process, the crude oil’s viscosity reduced significantly and the reduction varied according to different sampling wells with different dip angles and distances. The crude oil was greatly upgraded based on SARA fractions analyses. The content of saturates varied among those wells, and a higher value happened and was accompanied by the decrease of aromatics content during the early stage of ISC. Non-hydrocarbons content increased within the period of 4 years of investigation. It was found that the greater the asphaltenes content is, the higher will be the oil recovery (OR) obtained. The AN of oil increased remarkably during the ISC process. To some extent, the CHNO contents and H/C and O/C ratios of the oil samples could reflect the degree of oil modification; however, these values had not been found to correlate with the production performance. Polar compounds in the resins fraction such as carboxylic acids, ketones, and alcohols are detected, and the polar compounds that contribute to the increase of AN values of oils could be mostly from short-chain carboxylic acids, alkylphenols, and long-chain fatty acids.

The Investigation on Thermal Aging Characteristics of Oil-Paper Insulation in Bushing

Bushing is the key link to connect outer and inner insulating systems and also the essential electric accessory in electric power system, especially in the high voltage engineering (AC 1000kV, DC 800kV). This paper presented the experimental research of thermal aging characteristic of oil- paper insulation used in bushing. A thermally accelerated aging experiment at 90℃ was performed. The bushing models containing five layers of paper were sealed into the aging vessels and further aged for 250 days. Then several important parameters associated with the aging were observed and evaluated. The results showed that the degree of polymerization (DP) of papers gradually decreased. The DP values of outermost layer and middle layer fit well into the second-order kinematic model and first-order kinematic model, respectively. Less deterioration speed of the inter-layer paper than outer layer was confirmed by the variation of DP. Hydrolysis was considered as the main cause to this phenomenon. In addition, the logarithm of the furfural concentrations in insulation oil was found to have good linear relationship with DP of papers. Interestingly, when the aging time is about 250 days and DP is 419, the aging process reaches an inflection point at which the DP approaches the leveling off degree of polymerization (LODP) value. Both tanδ and acid number of oils increased, while surface and volume resistivity of papers decreased. The obtained results demonstrated that thermal aging and moisture absorbed in papers brought great influence to the degradation of insulating paper, leading to rapid decrease of DP and increase of the tanδ . Thus, the bushing should be avoided from damp and real-time monitoring to the variation of tanδ and DP values of paper is an effective way to evaluate the insulation status of bushing.

Prediction of Surfactant Retention in Porous Media: A Robust Modeling Approach

Demands for hydrocarbon production have been increasing in recent decades. As a tertiary production processes, chemical flooding is one of the effective technologies to increase oil recovery of hydrocarbon reservoirs. Retention of surfactants is one of the key parameters affecting the performance and economy of a chemical flooding process. The main parameters contribute to surfactant retention are mineralogy of rock, surfactant structure, pH, salinity, acidity of the oil, microemulsion viscosity, co-solvent concentration, and mobility. Despite various theoretical studies carried out so far, a comprehensive and reliable predictive model for surfactant retention is still found lacking. In this communication, a mathematical method based on machine learning approach, namely, least square support vector machine modeling is evolved for this purpose. To this end, the model was developed and tested using experimental dynamic surfactant retention data over a wide range of conditions. The results show that the developed model provides predictions in good agreement with experimental retention data. Moreover, it is shown that the developed model is capable of simulating the actual physical trend of surfactant retention versus three most important input parameters: total acid number of oil, pH, and mobility ratio. Finally, for detection of the probable doubtful retention data, outlier diagnosis was performed on the whole data set.