Showing 10 results for Crude Oil
Volume 6, Issue 1 (6-2022)
Abstract
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.
Volume 7, Issue 4 (1-2008)
Abstract
After the success of the revolution in the Islamic Republic of Iran, all polices regarding crude oil production and marketing have been revised and changed. Since the policies and methods of crude oil marketing were always influenced by political and economic conditions, and since the Islamic Republic of Iran has experienced different political and economic situations after the revolution, we tried in this paper to discuss the policies and ways of marketing and selling the crude oil in Iran. For finding the effective factors on the Iranian export crude oil prices from year 1979 (Islamic Republic of Iran revolution) till year 2005 and prioritizing them, we used Likert scale, but since the crude oil marketing experts couldn’t show the priority of effective factors by Likert Questioner, we used Analytical Hierarchy Process (AHP) to prioritize the factors. The findings show that, the quality of crude oil (API and Sulfur content) is the most important factor and “the General Terms and Conditions (GTC)” of National Iranian oil company ( NIOC) for selling Iranian export crude oil is the less effective factor on the Iranian export crude oil prices.
Volume 8, Issue 2 (10-2017)
Abstract
Crude oil is comprised of four groups: Saturates Aromatics, Resins and Asphaltenes. Oil pollution has irreversible effects on marine ecosystems. Therefore paying attention to oil pollution and the management of the ports is very important. Biodegradation of oil derivatives is more effective, more powerful and more economically efficient method for remediation in polluted sites rather than physicochemical methods. In this study, for isolation of crude oil degrading bacteria, seawater and mussels were collected from Persian Gulf. Enumeration of bacteria were done in collected samples. Isolated bacteria were identified by biochemical and molecular tests. Crude oil biodegradation for each strain was assessed by spectrophotometer and Gas Chromatography (GC). The results of this study show that the quantity and biodiversity of heterotrophic and crude oil degrading bacteria in Crassostrea gigas mussels was higher than surrounding environment (seawater). Eleven crude oil degrading bacteria were isolated from Persian Gulf, 7 strains were identified biochemically and 2 strains were selected on the basis of higher degradation. These isolated strains were identified as Shewanella and Alcanivorax. The half percentage of oil was removed by these strains in 15 days of incubation. These bacteria could be used for cleanup oil-polluted marine areas after more research and field observation.
Volume 9, Issue 2 (9-2018)
Abstract
Aims: Today, crude oil is one of the main sources of energy. The combustion of sulfur-containing compounds in fossil fuels leads to the production of sulfur oxides that has adverse effects to human health and the environment. At the moment, the current method for removal of sulfur is Hydrodesulfurization. The aim of this study was to investigate the effect of magnetic nanoparticles and modified carbon nanotubes as nano-adsorbent on improving the biodesulfurization activity of microorganisms (Rhodococcus erythropolis IGTS8).
Materials and Methods: In the current experimental study, the nanoparticles were synthesized by chemical co-precipitation and the carbon nanotubes were initially carboxylated. Multi-layer carbon nanotubes were mixed with 95% sulfuric acid and 52% nitric acid (volume ratio 1:3) and, then, modified by polyethylene glycol. In order to characterize nanoparticles and carbon nanotubes, scanning transmission electron microscopy (STEM), X-ray diffraction, magnetic surveys, analysis of arch Raman, and fourier-transform infrared spectroscopy (FTIR) were conducted.
Findings: The size of nanoparticles was estimated to be 7-8nm and modified carbon nanotubes showed the highest solubility as well as stability in deionized water for two weeks. The growth of microorganisms in the presence of magnetic nanoparticles and carbon nanotubes compared to their absence increased by 40% and 8%, respectively. Moreover the desulfurization activity of microorganisms in the presence of magnetic nanoparticles and carbon nanotubes showed a significant increase compared to their absence.
Conclusion: Nanoparticles with adsorption of sulfur compounds increase their availability for microorganisms.
Volume 10, Issue 2 (4-2021)
Abstract
Oil pollution of waters, in addition to disrupting the physiological function of fish, leads to irreparable damage to human health during transmission through the food chain. Therefore, the possibility of accumulation of petroleum hydrocarbons in the edible tissues of fish is of particular importance. In this study, samples of yellowfin seabream (Acanthopagrus latus; Houttuyn, 1782) were collected from the Khowr-e Musa area in the Persian Gulf using bait traps. after twenty days of adaptation to the laboratory conditions (South of Iran Aquaculture Research Center), the fishes was divided into five groups with two replications in tanks containing 300 liters of seawater. The groups were then exposed to concentrations of 0, 2, 4, 8 and 16% water associated fraction (WSF).
The results of the study of the amount of total petroleum hydrocarbons in the gills and kidney tissue showed a significant increase on days 10 and 20 of the experiment, which increased slightly with increasing WSF concentration (P <0.05). While liver and muscle tissue, considering exposure time and WSF concentration, no significant difference was observed (P> 0.05). The results of the present study showed the possibility of accumulation of TPH in the gill and kidneys of yellowfin seabream, under the influence of concentration and duration of exposure to WSF. Therefore, considering the high economic value of the Sparidae family, it seems necessary to provide appropriate management methods to control oil pollution in the Persian Gulf.
Volume 15, Issue 3 (11-2011)
Abstract
New Approaches in Forecasting Using
Neuro-Fuzzy Networks
(Case Study: The Crude Oil Price)
Mohammad Rahim Ramezanian1, Esmael Ramezanpour2,
Sayeed Hamed Pourbakhsh3
1- Assistant Professor. of Management, Guilan University, Guilan, Iran
2- Assistant Professor of Economy, Guilan University, Guilan, Iran
3- B.sc of Industrial Management, Guilan University, Guilan, Iran
Received: 17 /4/2010 Accept: 18/4/2011
Our world is a rapidly changing world. So it is very important for the survival of organizations to know what lies ahead in the future, how much demand is there for their products and for what price? We cannot afford big changes unless we are able to predict the future. The application of predictability science in management has been studied in this research. With the increasing progress of science, the use of new methods and application of new intelligent technologies have also increased. In this research, new methods and algorithms such as neural networks and fuzzy logic have been explained and the application of their combination in predictability has been studied. Various methods such as Moving Average Method, Weighted Moving Average, Exponential Smoothing, Double Exponential Smoothing, Linear Trend, Combined Functional Trend, and Exponential Process were used to make predictions. The results obtained from these methods were compared with the those obtained from the neru-fuzzy networks method using 6 error measurement criteria. It was found that the neru-fuzzy networks method yielded better results, and the correspondence of data (R2 coefficient) for the Neru-fuzzy networks was about 90 percent. The data used in this research were related to the Organization of the Petroleum Exporting Countries (OPEC) for the years 1970-2000.
Mohammad Amin Zoljanahi, Saadat Zirak,
Volume 16, Issue 2 (4-2016)
Abstract
This article presents a numerical investigation of fluid flow in one of the centrifugal pumps of pump-Iran Corporation. A computational fluid dynamics (CFD) analysis is performed by using the CFX software for a wide range of volumetric flow rates for two different rotor speeds of 1450 rpm and 2900 rpm and the numerical results of water are validated against measured values of head and total efficiency with an overall acceptable agreement. The obtained results have been obtained for crude oil as diagrams of head and total efficiency as the function of volumetric flow rate and other variables and compared with results of water. Numerical results show that the absolute pressure on blade surfaces for crude oil is 705 kpa less than when using water. The absolute pressure difference between inlet and outlet of impeller and spiral volute for crude oil is comparatively less than those amounts in comparison with water. Also by increasing the angular velocity of rotor, it was observed that high levels of turbulence intensity are transmitted from outlet pipe bending to the impeller outlet at volumetric flow rate of 30 m3/h that causes the efficiency reduction and high levels of turbulence intensity for crude oil are less than those amounts in comparison with water within impeller area. Finally, to represent an impeller pump head curve for crude oil over the overall operation range of the pump, a second order polynomial equation was fit to numerical data.
Volume 19, Issue 1 (5-2019)
Abstract
Removal of petroleum hydrocarbons from contaminated soil using electrokinetic method or biological processes has been considered in recent century. The most limiting factors in the electrokinetic process are extreme changes in pH around the electrodes and non-polarity of some pollutants. On the other hand, the key factor of biological treatment is simultaneous presence of microorganisms, pollutants (carbon source of microorganisms), electron acceptors, and essential nutrients for microorganisms’ growth. But in fine-grained soils with low permeability, it is difficult to uniformly distribute bacteria, electron acceptors and nutrients, or making pollutants available for microorganisms. To solve these problems, bioelectrokinetic method is used to eliminate the limitations of both biological and electrokinetic processes in treatment of fine-grained soil contaminated with organic compounds. In this integrative approach, the biological method has a role in biodegradation of pollutants. Whiles, the electrokinetic process can direct and accelerate the transfer of pollutants and microorganisms. The aim of this study is determining the equations and conditions governing on bioelectrokinetic process in removal of crude oil from clayey soil. For this reason, the numerical method of FTCS finite-difference was applied for modeling the pollutant biodegradation and transmission in clayey soil under electric field. In order to develop and validate the model, the first step was to set up a bioelectrokinetic system in a laboratory scale. In this study, each test was conducted in cylindrical cell made of Plexiglas with the length and diameter equal to 55 and 5 cm respectively, for 35 days. They were performed in various conditions of pollution amount and electric field intensity in the presence of Pseudomonas Putida strain. On the other hand, after determining and combining the governing equations on the electrokinetic and biodegradation system, the numerical solution of the equation was coded using Matlab software. In suggested mathematical model, the parameters like initial concentration of crude oil, voltage gradient, time step and spatial step were assumed as variables and parameters related to reactor, soil and pollutant such as the length of reactor, soil porosity and tortuosity, ion mobility, diffusion coefficient and electroosmosis permeability coefficient were considered as constants. In continue, by comparison the result of numerical solution of the suggested model with the experimental results, the same trend was observed in changes in crude oil concentration between the two. Because of differences between the model results and laboratory data and to make more accordance between the two, the modifying factor was used as the factor of microorganism transfer under electric field. In this way, by addition of modifying coefficient in model, a better accordance between them was observed and this difference reduced to minimum. Modeling results showed that electroosmosis, diffusion and electromigration mechanisms, unlike biodegradation, had little impact on the transmission and removal of oil from soil. According to the numerical solution, similar to bioelectrokinetic data, increasing the initial concentration of oil and voltage gradient caused the increase in removal efficiency of oil. In addition, the model has been able to predict the residual crude oil concentration after bioelectrokinetic treatment with a good accordance.
B. Sharifi, S.h. Hashemabadi,
Volume 19, Issue 6 (6-2019)
Abstract
In the present study, CFD simulation of Transit-time ultrasonic flowmeter with the PZT-5J piezoelectric sensor was modeled for light, heavy, and medium crude oil by the wave equation in the acoustic wave propagation path and finite element solving method in the unsteady state and it was implemented, using COMSOL Multiphysics 5.3 software. Different samples of light, heavy, and medium crude oil at different temperatures were modeled and simulated under constant pressure, using CFD tools. voltage and speed of sound in were calculated by the proposed model. To evaluate the accuracy of the proposed model, the simulation results were compared with the empirical data obtained from the experimental work of the researchers. The average values of the maximum voltage of signals for an ultrasonic containing light, heavy, and medium light crude oil samples are 0.9491, 1.0115, and 0.943 v, respectively. The difference between the simulation results and the experimental data for the speed of sound in the light, heavy, and medium crude oil samples was at most about 0.2336%, 0.4339%, and 0.1378%, respectively. Therefore, the high costs of designing and optimizing the transit-time ultrasonic flowmeter for crude oil can be reduced, using the proposed model.
Volume 21, Issue 3 (7-2014)
Abstract
In general, energy prices, such as those of crude oil, are affected by deterministic events such as seasonal changes as well as non-deterministic events such as geopolitical events. It is the non-deterministic events which cause the prices to vary randomly and makes price prediction a difficult task. One could argue that these random changes act like noise which effects the deterministic variations in prices. In this paper, we employ the wavelet transform as a tool for smoothing and minimizing the noise presented in crude oil prices, and then investigate the effect of wavelet smoothing on oil price forecasting while using the GMDH neural network as the forecasting model. Furthermore, the Generalized Auto-Regressive Conditional Hetroscedasticity model is used for capturing time varying variance of crude oil price. In order to evaluate the proposed hybrid model, we employ crude oil spot price of New York and Los Angles markets. Results reveal that the prediction performance improves by more than 40% when the effect of noise is minimized and variance is captured by Auto-Regressive Conditional Hetroscedasticity model.
