جستجوی مقالات مرتبط با کلیدواژه « crude oil » در نشریات گروه « فنی و مهندسی »

The proliferation of petrochemical industries and oil refineries in the western region of Hormozgan province has led to the placement of numerous concrete structures in close proximity to organic pollutants. This proximity has the potential to significantly influence the resistance parameters and durability of concrete. Therefore, the primary objective of this article is to investigate the short-term and long-term effects of exposure to organic pollutants from crude oil on the microstructural properties and strength of concrete. This research entailed the evaluation of approximately 360 concrete samples. These samples underwent a 12-month curing process in emulsions containing varying concentrations of crude oil (0.5%, 1%, 1.5%, 2.5%, 5%, 10%, 25%, 50%, and 100%). Compressive strength tests were conducted at intervals of 1, 3, 7, 28, 90, and 365 days, with concurrent analysis of changes in permeability coefficient. Microstructural examination was carried out using Scanning Electron Microscope (SEM) images, while structural analysis was performed using EDX. Additionally, X-ray Diffraction (XRD) tests were conducted to study the formation of hydration products in environments contaminated with crude oil and to analyze the crystalline structure of the materials. The results reveal that the resistance of concrete samples cured in crude oil emulsions depends on the concentration of the emulsion. Notably, the compressive strength of samples cured in 100% crude oil concentration emulsion decreased by approximately 41% after 365 days when compared to the control sample. Specifically, the compressive strength dropped from 41 MPa to 24 MPa, while the permeability coefficient increased from 3.2*10-7cm/h to 15.3*10-7cm/h.

With the expansion of oil industries, the leakage of oil materials increases. In addition to the negative effects of the environment, the oil leakage causes changes in the physical and geotechnical properties of the soil. These changes in granular soils are in the form of changes in the physical properties and structure of the soil, which leads to a decrease in the bearing capacity and an increase in the settlement of the soil under the foundation. In order to investigate the geotechnical behavior of fine-grained soils due to oil infiltration, a soil sample was taken from the Shazand Arak Refinery area and mixed with 0-5-10-15-20 percent crude oil by weight and remolded with a density of 90 percent of the maximum density (Proctor method) has been subjected to various physical and mechanical tests. Of course, the plastic index has a decreasing trend with the increase of the amount of crude oil. In the compaction test, the maximum dry unit weight of the soil increases with the addition of crude oil and the optimum moisture content decreases with the increase of the amount of crude oil up to 10% and then increases. In addition, the addition of oil generally reduces the permeability coefficient of the soil. Increasing the amount of oil has a different effect on soil consolidation, and the coefficient of soil consolidation increases with increasing the amount of oil. In addition, the uniaxial compressive strength of the soil decreases with the increase of the oil content.

Industrial activities, particularly in petrochemical and refinery sectors, have introduced a wide range of organic pollutants into the environment, leading to the pollution of aggregate materials with crude oil or petroleum products. This study investigates the influence of aggregate materials contaminated with crude oil and diesel on the cement hydration process and concrete properties. Around 90 concrete samples with polluted aggregates were evaluated over a 6-month period. Compressive strength tests and water absorption percentage tests were conducted at different ages. Microstructural analysis through SEM, structural analysis via EDX, and XRD analysis for hydration product characterization were performed. Results showed a significant reduction in compressive strength (47% and 31%) for samples contaminated with crude oil and diesel, respectively, compared to the control. Water absorption and permeability increased in polluted samples. SEM, and XRD, results indicated increased ettringite production, decreased nanostructure C-S-H, reduced strength and durability, and increased water absorption and permeability in the concrete. This study highlights the detrimental effects of organic contaminants on concrete properties, emphasizing the need for pollution management in aggregate materials for sustainable construction practices.

Hydrocarbon fouling of preheat exchangers causes several detrimental impacts on operation, environment, safety, as well as economy of oil refineries. To investigate threshold fouling models, a variety of hydrocarbon fouling data, such as temperature, oil flow, fluid properties, and geometries of such exchangers, has been gathered from the literature. The most accurate models for predicting the fouling rate are the Polley, Ebert, and Panchal models, with slopes of 0.352, 0.108, and 0.022, respectively, based on fitted curves on the computational fouling rates in terms of comparable experimental values. The sensitivity analysis indicates that the two factors that profoundly affect the fouling rate are the surface temperature and Reynolds number. Using the Polley's equation, the fouling rate in preheat exchangers may be predicted with the highest degree of accuracy, mean sensitivity analysis of 0.29, based on the consistency of calculated and experimental data.

Fouling in heat exchangers is main causes of energy losses in oil and gas refineries. One way to reduce this energy loss in these refineries is to predict fouling resistance. In this paper, the fouling resistance rate is first estimated using the Buckingham's dimensionless groups. The resistance rate is then validated with the experimental data derived from the literature. The results show the relative error of 26.79% with the experimental data, which is rather low and acceptable as compared by those reported in the literature ranged from 40-59%. In general, by estimating the fouling resistance rate, the fouling threshold curve can be plotted and the position of the exchangers relative to it can be checked. The position of the exchangers would allow to reduce the amount of fouling and to stay in non-fouling area with the proper justifications of the operating conditions. The curve is also used to estimate the deposition resistance in the unstable state with the asymptotic model. This model has also been validated with the experimental data from the Australian light oil and Tehran refinery data. It is worthy to mention that the prediction of fouling instability has been less considered in the literature, although with this estimate it is possible to have a better and more regular cleaning program for exchangers and to reduce the problems caused by deposition in exchangers leading to lower operational costs.

Mixing or dispersing operation is an important section in chemical processes. Because of several advantages like: low capital cost, low operating cost, low maintenance cost and low required space; static mixers are applied in many industries. In crude oil desalting process, static mixers for dispersion of the dilution water in crude oil is proposed by this study; which conventionally a mixing valve is used. Type of the static mixer in the applied operating conditions effects on the properties and the stability of the resulted emulsion. In a pilot scale setup, three types of SMV, HMS and LPD static mixers have been investigated; for different conditions of water fraction (2-15%) and crude oil flow rate (86-144 l/h). The experimental results show that SMV outcomes the most stable emulsion which is not appropriate for desalting process. Against, LPD is the optimal choice for the said application, regarding to the emulsion properties.

One of the most important aspects of governing physical processes through rough-walled fractures is the non-linear behavior of flow. The onset of non-linear flow in rock fractures is characterized by critical Reynolds number, which is the main object of this paper. In this paper, the technical aspects of non-linear flow of crude oil through open rock fractures and critical Reynolds number were studied. These issues were studied based on the results of three-dimensional numerical simulation of the Navier-Stokes equations for crude oil flow through rough-walled fractures. The finite volume simulation of crude oil flow through three-dimensional space of rough-walled fractures was performed for a wide range of Reynolds numbers or flow rates. The results of crude oil flow simulations were analyzed based on the Forchheimer’s law. The coefficients of energy losses due to viscous and inertial dissipation mechanisms were derived from the Forchheimer’s law regression on the results. Then, the role of linear and nonlinear energy losses with viscous and inertial dissipation mechanisms was evaluated based on the relation between Reynolds and Forchheimer non-dimension numbers. Finally, the critical Reynolds number was determined for onset of non-linear flow through rough-walled fractures. The results of this study indicate that the Forchheimer’s law appropriately describes the non-linear crude oil flow through rough-walled fractures. By increasing the Reynolds number (or flow rate), the ratio of viscous energy lose from total energy losses decreases non-linearly and simultaneously, the inertial dissipation becomes the dominant mechanism of energy lose. The critical Reynolds number for crude oil is in the range of 30 to 46 for the open fractures of this study. The maximum and minimum of critical Reynolds number follow the minimum and maximum of inertial dissipation coefficient and also the gradient of Reynolds- Forchheimer curve, respectively.

Oil extracted from the underground oil reservoirs contains heavy hydrocarbons.Heavy hydrocarbons include waxes,asphalts and resins that can appear as solids in compounds,which waxes are of particular importance.Changes in factors such as temperature,pressure,compounds of light components in petroleum compounds,etc.Cause the formation of solid paraffin wax deposits in these compounds.The wax precipitate formed mainly contains paraffins,naphthenes and to a lesser extent aromatics.The formation of these sediments in the first stage can block the underground pores, reduce their permeability and reduce the efficiency of oil extraction.In the next stages,the formation of deposits will lead to many problems. For example,it can clog pipes and increase flow resistance, resulting in a drop in flow pressure and,in addition to increasing the power required to pump fluid, cause premature depreciation of the facility.The issue of wax sediment formation and the factors affecting it have been discussed by researchers for many years and different methods have been studied to control it.In this project,by examining 1 nanoparticle of SiO2,as chemical inhibitor, acceptable results were obtained in reducing the wax appearance temperature(WAT).First,using differential scanning calorimetry analysis,a temperature of 250C was obtained for the crude oil cloud point.Then,by adding nanoparticles in different concentrations,this temperature was significantly reduced for different amounts of nanoparticles.Analysis of polarized optical microscopy also shows the change in structure of wax crystals to a disk like after the addition of nanoparticles. To investigate the flow behavior of crude oil,the apparent viscosity parameter was used at shear rates of 0.01,0.1 and 1 rpm and higher and lower temperatures of WAT temperature.Then,using wax deposition of oil samples by two analyzes of X-ray diffraction(XRD) and scanning electron microscopy(FESEM) with EDAX additive to study the dispersion of nanoparticles in wax deposits and changes resulting from the addition of nanoparticles in depositions was paid.In this regard,according to X-ray diffraction analysis,it was found that the nanoparticles had no chemical interaction with wax molecules,but was a confirmation of the results obtained in the analysis of differential scanning calorimetric analysis.The layered structure of the wax precipitate by adding nanoparticles to a fine-grained structure was also one of the results of scanning electron microscopy analysis.

Today, constant economic development at a global scale has become a nationwide demand that cannot be met unless oil production and export are boosted. A central treatment/export plant (CTEP) is a facility for the initial treatment and refining of crude oil. The originally produced crude oil contains a wide range of different compounds that must be removed before the oil can be exported. The CTEP is designed based on the type and quality of the locally available crude oil. It has a handful of different units which are responsible for separating different compounds from the crude so as to produce export-ready oil. For each ppm of increase in the water and/or brine content of the oil, its per-barrel price is expected to drop by 0.08 – 1.3 USD, clearly emphasizing the importance of the initial treatment of the crude.

The dielectric properties of a substance are the properties by which the effect of the utilization of electromagnetic waves can be studied. These properties should be investigated to study the electromagnetic heating method and optimization. In this study, seven oil samples from different fields were investigated, including Asmari, Sarvak, Sohrab, Fahlian, Kuh Mond, Mansouri, and Yaran. In this study, organic compounds and functional groups in crude oil were identified, and their effect on the dielectric property of oil was investigated. By examining the parameters affecting the dielectric property, it was concluded that the more polar compounds the compound has, the higher the dielectric and, therefore, the higher the ability to absorb microwave waves. The amount of dielectric property of Kuhmand, which is part of super heavy oil equal to 2.853 and Fahlian which is part of light oil is equal to 2.006, which shows that the heavier the oil between these two oil samples, the more Its electricity is higher and ultimately has a higher ability to absorb electromagnetic microwave waves. On the other hand, the bonds in the oil themselves also affect the dielectric. According to the FTIR test, the OH, NH, CN and SH bonds in the samples are directly related to the dielectric. The higher the concentration of these bonds is, the higher the dielectric is. In this project, the required links and functional groups within oil samples have been studied and discussed.

Several factors affect the bearing the load of natural and engineered embankments and slopes including the crude oil leakage, leading to a severe decrease in resistance. This is especially important for oil-rich countries, such as Iran, which have several crude oil resources. The main purpose of this study is to investigate the load bearing the load (i.e. load versus settlement) and strain-stress behavior of crude oil contaminated sandy soils using California Bearing Ratio (CBR) Test. In this paper, 10 different types of sand with different characteristics used. At first, a series of CBR experiments performed for natural sands (i.e. clean sands) and then contaminated sands with 6% crude oil tested under similar conditions and densities to obtain the reduction in bearing the load of crude oil contaminated sands quantitatively. Experimental results showed that bearing the load of sand containing 6% of crude oil decreased at least 50% compared to clean sands and the stress-strain diagram of these contaminated soils would decrease significantly. Based on the results of investigation, it can be stated that particle shape(sharpness or roundness), coarse particle ratio,and finally the type of aggregation influences the resistance of crude oil contaminated sands. It was also found that standard Ottawa sand had 83% reduction in strength and sand with a coarse particle had 57% decrease in strength. Sand contaminated with crude oil experience a severe loss of bearing capacity,so in designing foundations and engineering structures, greater safety factors should be considered, where there is a risk of crude oil leakage.

The environment is constantly exposed to various pollutants. Petroleum products may contaminate soils located next to industrial areas and other facilities. Oil pollution is one of the pollutions that can cause irreparable damage to the environment. Every day, a large amount of petroleum products enters the environment in various ways. Oil pollution affects the mechanical, chemical and dynamic properties of the soil. Changing the geotechnical properties of the soil is an important issue for structures adjacent to or on oil contaminated soil that can cause collapsing or variation in soil resistance. Since the behavior of many structures and foundations during dynamic loads is in the range of small strains, investigating and evaluating the velocity of waves in the soil skeleton can provide researchers and engineers with useful and significant information about the small-strain behavior of the soil. The importance and value of oil industry structures in Iran, as one of the active countries among oil exporting countries and as a country with a high level of seismicity, has made the research a vital way to improve the design level and accuracy of the behavior of structures exposed to pollution. Despite the wide range of oil industry structures in Iran and the other countries, there is limited literatures on oil-contaminated soil behaviors. Heretofore, the effects of diverse kinds of hydrocarbon contaminants on majority of geotechnical properties of clay soils such as grain size, hydraulic conductivity, plasticity, compressibility, internal friction, cohesion, and shear strength have been investigated. However, there has not been a concentrated research study examining shear wave velocity of hydrocarbon-contaminated clay soils as an important geotechnical property of soil due to the fact that, in small/very small strain levels, the maximum shear modulus of soils can be determined using shear wave velocity. This study aimed to measure the shear wave velocity and consequently, identify the shear modulus of clay soils in oil-contaminated condition with different percentages of contamination, and to compare them with non-oil-contaminated clay soils on small-strain range, using a Bender Element system. In order to prepare comparable clean and contaminated samples (containing 2, 4, 6, 8, 10 and 12 weight percent (wt%) of crude oil, respectively), it was performed similar to the density test method. In this regard, all the clean and contaminated clay samples were tested with a minimum moisture content equal to the optimal moisture content. Bender element tests were conducted on the identically prepared clean and contaminated clay samples at various amounts of frequency (5–20 kHz) and under various confining pressure (50–500 kPa) to find the best method for accurately determining shear wave travel time in the Bender Elements tests. Thereafter, Bender Elements placed in triaxial cell in Razi university laboratory. Bender Elements test conducted to examine shear wave velocity in the clean and contaminated specimens. As a contribution to the literature and potential engineering application, the experimental test results indicated that whilst adding 10wt% of crude oil in clay samples with an increase in the confining pressure, it correspondingly increase the shear wave velocity and consequently increase the shear modulus among of all samples. In addition, at each level of confining pressure, the shear modulus of clean clay was lower than the other contaminated samples. Moreover, under all confining pressures and excitation frequencies, the addition of 10wt% of crude oil caused significant changes in the maximum shear modulus, which was due to the effects of hydrocarbons on the behavior of clay particles. The degree of change due to hydrocarbons is highly dependent on the amount of confining pressure, so that the more the confining pressure is increased; the shear waves velocity an then the shear modulus is increased.

During recent years, Gemini ionic liquids (ILs), as a new type of surfactants, have gained much attention due to their significant interfacial activity. Accordingly, use of these materials to reduce crude oil-water interfacial tension (IFT) and to enhance oil recovery is much advantageous. In this study, effects of concentration, temperature and pH on the crude oil-water IFT in the presence of Gemini IL surfactants were investigated. For this aim, alkyl chain length imidazolium based gemini ILs of [C4im-C4-imC4][Br2] and [C8im-C4-imC8][Br2] were synthesized and used. By measuring IFT of the system, under different conditions, the corresponding variations were considered. Results revealed the strong effect of alkyl chain length and concentration on the IFT, leading to, respectively, 72.5 and 97.5% reductions under critical micelle concentrations and temperature of 298.2 K. The Gemini IL surfactants were stable at high temperatures and under a wide range of pH, and that their performance was significantly promoted with these factors. In theoretical investigation, it was revealed that the experimental data were nicely consistent with the Frumkin adsorption isotherm and the obtained parameters with reasonable variations.

Risks in the energy sector are usually very low in frequency but very high in intensity, which has made the energy sector of any country a high-risk sector. Therefore, to cover its risks, appropriate insurance policies must be designed and implemented. The design of such insurance policies requires accurate identification of all risks, determination of their acceptance criteria, and finally doing actuarial calculation for the designed product. This article just focuses on insurance for crude oil and gas refineries in operation. First, based on the literature review, the risks in this field are identified and then, based on the opinions of health and safety experts and risk assessors working in the field of energy, the model for assessing such risks develops in the form of a risk assessment matrix. A Bayesian structural equation modeling using the Amos has been employed to study impact of the presented variables. Then, referring to the information available in the insurance industry, the pricing of this insurance product is presented based on the rate and the sum insured.

Fossil energies is directly and indirectly effective in all activities, and interrupting its supply can cause various problems; This has led countries to diversify their energy resources and reduce their dependence on one carrier. On the other hand, environmental considerations have led to a more serious trend towards alternative energy sources. Therefore, determining the interaction between the price of crude oil (as an indicator of fossil fuels) and the use of alternative energy, given that over time the possibility of changing this relationship under the influence of technological development, economic policies and Relative prices, etc. are very important for energy policy and planning. Therefore, in this study, using state space models and applying Kalman filter, the variability of the interaction of crude oil prices and investment in alternative energy during the period 1995-2017 for the entire energy market, to determine the relationship between these two variables. And the possibility of variability of this relationship over time has been investigated. The results show that the price of crude oil has a significant effect on the investment of most alternative energy sources, but the effect of investing in alternative energy on the price of crude oil is weak or insignificant and no variability was observed in this regard. The effect of investing in solar and wind energy on the price of crude oil is somewhat acceptable that it is predicted that with the growth of these energies and increasing the share of energy market demand, their impact on crude oil prices will be greater than before.