Sharif Digital Repository

Hydrocarbon contaminations due to their volatility, solubility and biodegradability properties can enter the vadose zone and adversely influence the soil properties. Recently, some deep and superficial signs of oil pollution have emerged in the soils around the refinery of Sarkhoun. In order to assess the exact type and behavior of pollutants, evaluate the environmental attributes and measure some important factors of oil contamination in this region, and also to see how pollution transfer in the underground environment, this study has been done. Materials & methods Sarkhoun refinery is located 50 kilometers away from ar Abbas in the northeast direction. The area is mostly composed of Marne... 

Interfacial tension is one of the very important parameters in pharmacology science, chemical engineering and petroleum engineering. The interfacial tension between pure hydrocarbons and water is widely used in chemical and petroleum engineering and so that it is highly desirable to find its accurate values. In this study a new unique correlation has been developed based on a comprehensive database of pure hydrocarbons-water interfacial tension values which contained both aliphatic and aromatic compounds (32 different hydrocarbons) with pressure ranges of 0.1-300 MPa and temperature ranges of 252.44-550 K. The proposed correlation uses the density difference between pure hydrocarbon and... 

Combined experimental and theoretical studies on the reactivity of iodosylbenzene (PhIO) show that PhIO is capable of activating weak C-H bonds of hydrocarbons via a hydrogen abstraction mechanism. © 2009 The Royal Society of Chemistry  

In this paper, an object oriented method is developed for generation, optimization and management of a hydrocarbon (CxHy) pyrolysis reaction network using a Bond-Electron (BE) matrix. A computer program was developed using C++ language. This program can provide and generate a pyrolysis reaction network for a wide range of hydrocarbons, including alkanes, olefins, diolefins, cyclic and aromatic compounds, using the linear notation structure of the reactant species. Furthermore, the reaction patterns and pruning methods are considered and a new method is presented for identification of reactants and products. The structural identification of species contained in the network allows one to... 

This article discusses the distribution of total petroleum hydrocarbons (TPH) contamination in soil within areas of the South Pars Gas Complex (S.P.G.C.), located on the northern shore of the Persian Gulf. To assess the potential risk to groundwater, in situ contaminant mobility was also examined in vertical soil profiles. Sampling was conducted in two rounds, and TPH was determined in accordance with standard methods of TPH analysis. The maximum detected concentration was 10268±785 mg/kg in the area of the waste disposal site. Significant heterogeneity in natural attenuation of different hydrocarbon compounds during transport in the soil was observed. Although the groundwater samples did... 

Indigenous thermophilic hydrocarbon degraders are of special significance for the bioremediation of oil-contaminated desert soils with ambient temperature of 45-50°C. The first objective of this study was to demonstrate the hydrocarbon-degrading capability of Nocardia otitidiscaviarum TSH1 (DSM 45036) which grows optimally at 50°C. Analysis of the metabolic profile of the strain TSH1 showed that it could metabolize phenol, intermediate-chain-length n-alkanes and some polycyclic aromatic hydrocarbons (PAHs) ranging in size from two to four fused rings efficiently, but not toluene and xylene. N. otitidiscaviarum TSH1 was able to survive and grow at phenol concentrations up to 875 mg l-1. For... 

A pyrrole-based polymer was synthesized and applied as a new sorbent for solid-phase extraction (SPE) of some environmental pollutants from water samples. Polypyrrole (PPy) was synthesized by chemical oxidation of the monomer in nonaqueous solution. SPE of selected phenols, pesticides, and polyaromatic hydrocarbons (PAHs) from aqueous samples were performed using 200mg PPy. The determination was subsequently carried out by gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The polymer showed much higher recoveries for aromatic compounds than aliphatics. Preconcentration of sample volumes up 1l led to acceptable recoveries for aromatic and... 

The ability of Rhodococcus sp. P32C1 for desulfurization of n-hexadecane (n-C16) containing dibenzothiophene (DBT), and two different diesel oils is evaluated. Cells cultivated in the medium containing DBT of 0.1 mM showed higher desulfurization activity, and the effects of cell concentration on the desulfurization reaction were studied. Three hydrocarbon-aqueous phase ratios of 25, 50 and 75 vol.% were used for desulfurization of n-C16 containing 1 and 24mM of DBT as a sulfur source. The maximum specific production rate of 2-hydroxybiphenyl (2-HBP) in two-phase system was 43.5 mmol/(kg dry cell.h). Based on the optimum conditions determined for desulfurization of n-C16, diesel oils with... 

The petroleum industry tends to paint an optimistic picture with respect to future petroleum availability. In order to anticipate demand, the size of connected volume of hydrocarbon of fields needs to be known. During the early stage of life of a reservoir, due to the lake of certain data, connected volume of hydrocarbon is usually based on analogues or rules of thumb and not detailed reservoir modeling. Therefore, there is a great incentive to produce physically-based methodologies to make an estimation of connected volume of hydrocarbon. Percolation theory is used to estimate the connected volume of hydrocarbon very fast. Furthermore, the result has been validated against areal field... 

A model based on the perturbation theory of fluids was proposed to correlate the experimental data for surface tension of pure hydrocarbons in a wide range of temperature. The results obtained for the pure hydrocarbons were directly used to predict the surface tension for binary hydrocarbon mixtures at various temperatures. In the proposed model, a modified form of the square well potential energy between the molecules of the reference fluid was taken into account while the Lennard-Jones dispersion energy was considered to be dominant amongst the molecules as the perturbed term to the reference part of the model. In general, the proposed model has three adjustable parameters which are chain... 

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... 

The present study was carried out to evaluate the degradation efficiency of benzene, toluene, and xylene (BTX) by isolated bacteria from various petroleum-hydrocarbons contaminated sites. Five isolated bacteria were selected for testing BTX biodegradation from liquid culture media. Each of these bacteria was able to degrade BTX but with different efficiencies. Maximum biodegradation efficiency for benzene (more than 70 %) was obtained by Gram-positive coccobacillus, Gram-positive coccus and Gram-negative bacillus bacteria, for toluene (60 %) and xylene (70 %) by Gram-positive coccobacillus and Gram-negative coccobacillus. It was found that the presence of xylene in the substrate mixture... 

The connectivity between two points in porous media is important for evaluating hydrocarbon recovery in underground reservoirs or toxic migration in waste disposal. For example, the connectivity between a producer and an injector in a hydrocarbon reservoir impact the fluid dispersion throughout the system. The conventional approach, flow simulation, is computationally very expensive and time consuming. Alternative method employs percolation theory. Classical percolation approach investigates the connectivity between two lines (representing the wells) in 2D cross sectional models whereas we look for the connectivity between two points (representing the wells) in 2D aerial models. In this... 

The current transition to a greener economy affects world markets dynamics. Given the considerable hydrocarbon dependency, we scrutinise the resilience of the Russian fiscal stance to international oil and gas prices at the first phase of this study. In doing so, we apply Cross-Quantilogram and Dynamic Simulated Autoregressive Distributed Lags (DSARDL) to analyse time-series data from January 2011 to August 2021. Our investigation demonstrates the fiscal stance (FS) positively responds to positive oil price shocks at medium quantile of FS and at lower to the higher quantile of oil price. The degree of responsiveness of FS to oil price is profound in the medium memory due to the time lag of... 

Reduction of cold start hydrocarbon (HC) emission requires a proper compromise between low engine-out HC emission and fast light-off of the three way catalytic converter (TWC). In this paper a model based approach is used to design and optimize a hybrid switching system for reducing HC emission of a mid-sized passenger car during the cold start phase of FTP-75. This hybrid system takes the benefit of increasing TWC temperature during the early stages of the driving cycle by switching between different operational modes. The switching times are optimized to reduce the cumulative tailpipe HC emission of an experimentally validated automotive emission model. It is shown that the new hybrid... 

On July 24th, 2010, several explosions and fires devastated a hydrocarbon processing plant in Kharg Island, Iran. Four workers were killed and many others were severely injured. The plant became out of service for 80 days. The way the accident happened and its sequence was representing as a domino accident. In this paper, events leading up to the disaster have been analyzed in details. Graphic presentation techniques such as Fish Bone Analysis and Event Sequence Diagram (ESD) have been utilized to enhance the understanding of the accident mechanism. Finally major lessons learnt from this domino accident have been addressed  

In this work a series of hydrocarbon solvent injection experiments was performed on glass micromodels with different throat orientations that were initially saturated with crude oil at several fixed flow rate conditions. The solvent concentration as a function of location and time was measured using image analysis of color intensity of continuously provided pictures during the injection process. The provided concentration calibration curve of solvent in crude oil was used for back-calculating the solvent concentration along the dispersion zone. The longitude and transverse dispersion coefficients were determined by fitting the results of the mathematical model to the experimental data. It... 

Estimation of petroleum fractions properties is one of the major problems in the reservoir fluids analysis, due to the fact that they cannot exactly be diagnosed and their constituents are not available clearly. In this study, a simple model has been developed to estimate the viscosity of pure hydrocarbon substances, bitumens, size-asymmetric mixtures and reservoir fluids (containing unknown hydrocarbon mixtures or petroleum fractions). The proposed model has been extended based on the two conventional and physical properties which can be measured for both pure components and unknown mixtures, without requiring to have their components and compositions. This model uses the pressure (P),... 

The efficient production of syngas from a CH4+CO2 mixture in an atmospheric pulsed glow discharge, sustained by corona pre-ionization, has been investigated. The products were mainly syngas (CO, H2) and hydrocarbons up to C4, with acetylene having the highest selectivity. The energy efficiency was within 15-40% for different experimental conditions, which demonstrates a comprehensive improvement relative to the achievements of other types of non-equilibrium plasma. These values are, however, comparable with the efficiencies obtained by gliding arc plasmas but this plasma operates at near room temperature. Furthermore, it has been shown that the energy efficiency is increased by decreasing... 

The power law logistic model was utilized to investigate the growth of a hydrocarbon assimilating bacterium on a water-insoluble substrate. To achieve this end, population dynamics of Bacillus licheniformis MS3 in a medium containing n-decane as the sole carbon source was monitored for 30 h. Different initial biosurfactant concentrations and shaking rates were employed to examine the role of mass transfer in the cell growth and the consequent hydrocarbon biodegradation. The amount of n-decane degraded in the system was detected by gas chromatography at the end of the incubation period. The results revealed that when mass transfer limitations were lessened through addition of an initial...