شهریار عصفوری

Dye-sensitized solar cells (DSSCs) are a newer generation of solar cells that, although they have lower efficiency compared to silicon-based solar cells, have a high potential for improved efficiency. Due to their better cost-effectiveness, they can replace silicon-based solar cells in the market if their efficiency and stability increase. The design and development of DSSCs have involved not only experimental and laboratory work but also numerical modeling. The aim of this work is to design and numerically model dye-sensitized solar cells based on a nanostructured semiconductor layer with a wide bandgap (titanium dioxide) and zinc oxide as the electron transporter, N719 dye as the absorber layer, and PEDOT:PSS and P3HT as hole transport materials. In this research, the advanced software CAMSOL with extensive capabilities is used for the design of dye-sensitized solar cells, and the current-voltage characteristics and optical absorption of the cell are calculated, which are in agreement with experimental data.

Storage and dispose of CO2 in aquifers is a promising techniques to mitigate global warming and reduce greenhouse gases (GHG). Measurement of CO2 dissolution rate in saline aquifers is dependent on the finding an appropriate model for gas diffusion. Indirect methods, especially pressure decay, are currently being used to measure molecular diffusivity. The most important point in this method is the useage of appropriate model and analyze the experimental results. In this paper, non-Fick modeling method is used to analyze the experimental data of pressure decay method for CO2 emission in saline aquifers and the results are compared with Fick model with two different types of boundary conditions. For this purpose, by the inverse solution and minimizing the error function between the pressure-time values of the modeling and the experimental using optimization are estimated diffusion coefficient, mass transfer coefficient and delay time. The results show that with respect to the non-equilibrium boundary condition the diffusion coefficient was more than doubled compared to the equilibrium boundary condition and the non-equilibrium boundary condition is more consistent with the experimental results. On the other hand, the nonfickian model delays the equilibrium arrival with a delay time regulator term and is more consistent with the experimental results, especially in the early moments.

Liquid blockage decreases gas condensate productivity when the reservoir pressure near the wellbore falls below the dew point. Wettability alteration is the most promising method among various techniques to overcome the liquid blockage. In this study, the ability of different chemical solutions to change the wettability of rock types; carbonate and synthetic rocks from liquid-wet to a gas-wetting state was investigated. Contact angle measurement was conducted to evaluate the effect of the treating process. It was found that some of the best solutions containing COUPSYL®WRS nanofluid, PTFE, hydrophobic SiO2 nanoparticles + PDMS, could change the water contact angle from 0° to 130.5°, 142.7°, and 155°, respectively. They could also produce water repellency conditions. In contrast, they were not effective on the synthetic rock surface. Moreover, the contact angle of condensate did not change by using these chemicals and remained at 0°. It was also shown that by increasing SiO2 nanoparticle concentration from 0 to 2 wt%, the water contact angle increased from 117° to 155°, which was the most effective chemical solution in the wettability alteration process.

In the gas condensate reservoirs, the trapping phenomenon is caused by the capillary force of the rocks. The force that leads to remaining liquids in pores. There are various methods to eliminate the condensate or reduce it to a minimum value. Many researchers attempt to recover more oil commercially and delay leaving gas condensate fields by innovating some new methods such as nanotechnology. The main goal of this study is the reduction of the trapped condensate by applying CaCO3 nanofluid injection (the natural CaCO3 (Bio-Ca) nanoparticles containing chitin) in the sand pack. This is known as an economical and eco-friendly nanoparticle in tertiary enhanced oil recovery method. Finally, the displacement efficiency (ED) and recovery factor (Re) of this nanoparticle was 5.23% and 69.29%, respectively. The optimum values of the initial condensate saturation (Soi) and the flow rate of nanofluid injection (qNF) are 30 and 5cc/min, respectively. These values are the minimum Soi and qNF, which considered in this study

Simplified hard dimer chain theory combined with the perturbed chain statistical association fluid theory (PC-SAFT), which is used for binary systems of normal alkanes by Nasrifar, was developed to carbon dioxide-hydrocarbon, nitrogen-hydrocarbon, and natural gas systems. The parameters m, σ, and ε / k for carbon dioxide, nitrogen, isobutane, and isopentane were calculated. The results showed that for these components, the average absolute error obtained using this equation for the vapor pressure of carbon dioxide, nitrogen, isobutane, and isopentane was 2.7, 0.3, 2.1, and 2.2; and for the saturated liquid volume was 1.2, 1.1, 3.1 and 1.5, respectively. Using kij for correction of dispersion interactions, vapor-liquid equilibrium of carbon dioxide- hydrocarbon and nitrogen-hydrocarbon systems were investigated and the results of this equation were compared with the SAFT and PC-SAFT equations, respectively. The results showed that the model has better performance than these two equations of state. Finally, the model was used to predict the dew point temperature of natural gas mixtures, and for these systems, the error obtained from the prediction of the model was lower than the PR78 equation.

Collagen is a protein that constitutes a major component of connective tissue and has many applications in the medical and non-medical fields. The increase in the world population and the need for proteins have led to a special focus on seafood. Furthermore, jellyfish is a rich and renewable source of collagen. Therefore, many researchers have shown interest in collagen extraction from jellyfish. This study aims to extract and purify collagen from jellyfish Catostylus mosaicus.

Acid-soluble and pepsin-soluble collagens were extracted and purified using a membrane with a MWCO of 100,000 from jellyfish Catostylus mosaicus. Protein content, type, denaturation temperature, and functional groups of the extracted collagens were evaluated using spectrophotometer, electrophoresis, viscometry, and Fourier transform infrared (FTIR) spectroscopy, respectively.

The results showed that pepsin-soluble collagen extracted from the umbrella and arm of the Catostylus mosaicus jellyfish consisted of chains α and dimer β, and the yields of the pepsin-soluble collagens extracted from the jellyfish umbrella and arm were 14.58% and 12.8% of the dry weight. The results also showed that the denaturation temperature of collagen extracted from the jellyfish arm and umbrella were about 27.32  and 28.72 , respectively. The FTIR spectra of pepsin-soluble collagen from the jellyfish umbrella and arm were almost identical to other types of collagens.

The results show that this species of jellyfish can be used as a renewable marine source of collagen instead of other sources of collagens.

CO2 concentration, as the main greenhouse gas, is growing in atmosphere and many alternatives have been investigated to deal with it. However, harnessing with the aim of biomethanation seems to be more economic.

In this study a mass transfer modeling was conducted for a biomethanation process under a batch strategy aiming at maximizing liquid active volume. The accuracy of modeling results was assessed via comparing with experimental data and kinetic results under zero-dimension study. Then one-dimensional study was conducted in order to investigate biomass and hydrogen concentration profiles within liquid phase of the bioreactor and active volume calculation. Response surface method (RSM) was also served to investigate effect of temperature, pressure and as three main factors on active volume followed by response optimization.

Model accuracy was confirmed by zero-dimension study. One-dimensional study was also revealed that biomass growth dispersion within liquid phase depends on hydrogen profile concentration on condition that both hydrogen and biomass diffusion coefficients were assumed to be equal. Their degree of magnification was 10-9  in standard conditions. RSM showed that the three studied factors significantly affected on bioreactor active volume. Meanwhile, pressure and temperature influenced the most, respectively.

A batch bioreactor with  and high pressure and temperature met optimal conditions for biomethanation; however, process economy defines operational limitations.

Gas is injected into reservoirs for pressure maintenance, enhanced oil recovery and greenhouse gas storage. The molecular diffusion coefficient is one of the most important mechanisms in describing the mass transfer of gas during injection. The molecular diffusion coefficient is determined using indirect methods like pressure decay method associated with appropriate models and analyzing the experimental results. In this study, analytical methods for analyzing the experimental data from the pressure decay method were evaluated. For this purpose, three analytical solution methods of diffusivity equation were introduced using equilibrium, quasi-equilibrium and non-equilibrium boundary conditions at the interface of two phases in contact with the diffusion cell. Then, the models were applied for determining diffusivity in different fluid systems of heavy and light oil. The evaluation of the proposed models was based on the difference between the production pressure by these models and the experimental pressure. The results showed that for heavy oil systems, the boundary conditions on the surface is dependent on the type of the injection gas and the experimental conditions. Equilibrium boundary conditions are used for light oil systems because of their lower viscosity and continuity at the interface of two phases.

In order to study the effect of organic amendment application on the growth and biochemical characteristics of French marigold (Tagetes patula) in soil contaminated with different levels of gas condensate, a factorial experiment was conducted based on a completely randomized design with three replications. The experimental factors consisted of gas condensate at five levels of 0, 7,500, 15,000, 30,000 and 60,000 μL per kg of soil, and soil amendment including vermicompost (5%), biochar (2%), Activated carbon (1%), vermicompost+ activated carbon+ biochar and non-amendment treatments. The results of the analysis of variance showed that the main and interactive effects of gas condensate and soil amendments were significant on traits of fresh and dry weight of root and shoot, chlorophyll a and b and proline content (P < 0.01). At the highest level of contaminant, the application of activated carbon and vermicompost+ activated carbon+ biochar respectively caused 3.82 and 4.45-fold increase in shoot fresh weight, 3.76 and 4.4-fold increase in root fresh weight, 2.52 and 2.56-fold increase in chlorophyll a, and also decreased 30.66 and 39.5 percent of proline content compared to the non-amendment treatment at this level of contaminant. The results of this research indicated the effective and useful role of organic soil amendment, especially activated carbon and vermicompost+ activated carbon+ biochar in reducing the toxicity of gas condensate on French marigold.

Nowadays, in order to preserve the environment and sustainable development, the use of natural and renewable resources is a priority for industries. High performance and specific structure of nano-biocompatible materials has attracted researchers. In this research, alginate polymer, which is
generally obtained from marine sources such as algae, was added to polyvinyl alcohol nanofibers in order to improve their biocompatibility and investigate the effect of solution parameters on their morphology. Polyvinyl alcohol nanofibers were produced in different concentrations by electrospinning to investigate the effect of concentration, adding alginate polymer and Triton x-100 surfactant. The quality of nanofibers and rheology behavior of polymer solutions were evaluated using scanning electron microscopy, rheometry and tensiometer. The results showed that increasing the concentration of polymer solution increased the diameter of nanofibers, as well as the viscosity of the polymer solution, such that a polyvinyl alcohol solution with 10wt.% concentration produced more uniform nanofibers. At first, adding alginate to the polyvinyl alcohol solution deteriorated electrospinning, however, production of nanofibers was improved by increasing polyvinyl alcohol solution to 10wt.%. Also, the results showed that adding Triton x-100 surfactant to the polymer solution affected the dominant mechanism in electrospinning by reducing surface tension and viscosity of the solution at polyvinyl alcohol solution 6wt.% and 10wt.%, respectively. Under optimized conditions of solution parameters, suitable nanofibers will be produced, which will be applicable in many industries, such as drug delivery.

Cuttlebone is composed mostly of CaCO3 and chitin, and can be used as a natural source of CaCO3 nanoparticle production.
In this study, ball milling and dispersion of initial powder in a surfactant, cetyl trimethyl ammonium bromide (CTAB) aqueous solution were used to produce CaCO3 nanoparticles from cuttlebone (Sepia pharaonis) of the Persian Gulf. Then, the results of the two methods were compared. Field Emission Scanning Electron Microscopy (FESEM) and Dynamic Light Scattering (DLS) were used to characterize particles.
The results showed that two hours grinding of the initial powder produced nanoparticles of 44 nm diameter. Moreover, increasing the grinding time had a direct effect on reducing the size of the nanoparticles. The obtained results from dispersion of initial powder in surfactant aqueous solution indicated the great result of nanoparticles of 40 nm diameter.
The capability of cuttlebone powder (Sepia pharaonis) of the Persian Gulf to produce nanoparticles in a process characterized with low energy consumption and low processing time suggests that it may be used at industrial scale for the synthesis of biocompatible nanoparticles

The most important mechanism of microbially enhanced oil recovery processes is changes in interfacial properties of fluid/fluid/rock affected by bacterial cells and their metabolites. In this study, two bacteria B.licheniformis and P.putida and three different sources of carbon were used. Results showed that due to the effect of carbon source on bacterial growth and also type and value of produced metabolites, changes in interfacial properties of fluid/fluid/rock is affected by used carbon source. The better growth of both bacteria occurred in a culture medium containing glucose. Pendant drop tensiometry, electrophoretic mobility measurement, interfacial dilational rheology and contact angle test were used to investigate the effect of cell structure and culture medium composition on interfacial tension reduction, emulsion stability, and wettability alteration mechanisms. The results of this section showed more potential of P.putida bacteria in surfactant production. Also, results showed that glucose is a better culture medium for B.licheniformis bacteria. Produced biosurfactants and bacterial culture of B.licheniformis bacteria in medium with glucose carbon source reduced surface tension and interfacial tension by 29.07% and 43.87%, respectively. Submerging thin section in glucose culture medium of B.licheniformis bacteria reduced the contact angle of water drop from 109.081 to 44.898°. In the case of P.putida bacteria, the oily and glucose culture media are respectively the effective media for influencing the fluid-fluid and fluid-rock interface. The produced biosurfactants and bacterial culture of P.putida bacteria in medium with olive oil carbon source reduced surface tension and interfacial tension by 36.4% and 27.1%, respectively. The contact angle of drop water was reduced from 109.081 to 54.050° in glucose culture medium of P.putida bacteria

Applicability of nanoparticle in oil and gas industry has brought much attention, particularly in enhanced oil recovery. Various factors including reservoir type, geological properties, wettability of the surface and fluid distribution influence efficient production from reservoir. Employing nanofluid for wettability alteration has been of great importance and provide favorable wettability state. Wettability alteration of reservoir rock increases production rate and reduces the residual saturation of the fluid in the porous medium. Reservoir rock surface consists of minerals with different adsorption properties that can influence wettability of the rock. In this paper, a fundamental of wettability is explained furthermore, the ability of different nanoparticles in wettability alteration of different rock types are investigated for enhanced recovery from oil and gas reservoirs with certain rock type.

Development of Carbon Capture and Storage (CCS) technologies in saline aquifers is a tool to reduce environmental effects of CO2 emissions and climate change. Dissolution of CO2 in water provides an option for storage in saline aquifers. When CO2 dissolves in the water, the density of the solution increases. Then it may cause natural convection which in turn, increases the rate of dissolution and safety of the storage. In this paper, dissolution process and storage of CO2 in saline aquifers is studied. Here, the main purpose is to investigate the effect of porosity and permeability and anisotropicity of reservoir rock on dissolution process, onset of natural convection, time of maximum Sherwood number. To this end, numerical simulation of convective mixing in both isotropic and anisotropic reservoirs has been reported. The results show the three effective period of CO2 storage in aquifers. Comparisons of the results reveal that permeability has significant effect on the onset of convection and convection mixing process. Therefore it is one of the main factors that should be considered in choosing the storage site.

The use of dimethyl sulfoxide (DMSO) as a solvent for organic and inorganic compounds in various industries such as pharmaceutical, electronic and acrylic fiber manufacturing process has been increased in recent years. According to the growth of these industries in recent decades, treatment of DMSO wastewaters has become a serious concern. Although DMSO itself has low toxicity, the biological treatment of wastewater containing DMSO, is known to be difficult. According to limitations of biological treatment due to production of toxic compounds, advanced oxidation processes (AOPs) is considered as a most efficient method and the best one for purifying organic compounds which are resistant to conventional physical and chemical processes. In this study, some important AOPs such as extended and hybrid Fenton processes (photo- Fenton, electro- Fenton and photo-electro Fenton), ozone-based processes (O3, O3/H2O2, O3/UV), UV/H2O2 and TiO2/UV have been studied in the treatment of wastewaters containing DMSO. The efficiencies of these processes were also evaluated and discussed. Overall, it can be concluded that hybrid Fenton processes and ozone-based processes are more effective for removal of DMSO from wastewater.

The simultaneous utilization of Disulfide Oil (DSO) and Condensate is known as a novel mixture that has drawn researchers’ attention. The usage of such products is applicable when only precise experimental physico-chemical data are available. The DSO is produced as a waste and byproduct of gas sweetening process, which contains several disulfide components. Moreover, condensate is known as a valuable industrial product that is liquid at atmospheric temperature and pressure. Adding condensate to DSO makes it more economically feasible for export and may upgrade thermo-physical properties of DSO.Moreover, adding condensate to DSO promotes its potential applications. In this research work, different volume fractions of these two products from zero (0%) to 100% of DSO were tested by Refractometer, Tensiometer, Rheometer, Salinometer, and Calorimeter. It was found that the obtained refractive indexes linearly decreased from 1.5215 to 1.4277 by increasing the volume fraction of condensate at ambient temperature and pressure.Subsequently, the surface tension values decreased from 30.6 to 19.9 mN/m via quadratic function. The Rheometer results showed that various mixtures of these two products depicted a Newtonian fluid behavior in which their viscosity increased from 0.54 to 0.69 mPa.s by adding DSO at a standard temperature of 15.5˚C. The salt concentrations in condensate and DSO were achieved 26.096 and 30.265 g/m3 respectively. The calorific value of DSO was almost half of that of condensate value. It was observed that the condensate heat of combustion reduced by adding DSO.

In this work, an equation of state has been utilized for thermodynamic modeling of aqueous electrolyte solutions. The proposed equation of state is a combination of simplified statistical associating fluid theory (SAFT) equation of state (similar to simplified PC-SAFT) to describe the effect of short-range interactions and mean spherical approximation (MSA) term to describe the effect of long-range interactions. In this model, the salt- based approach or restricted primitive model has been used to adjust the four parameters of the model. The salt (ion) parameters have been estimated through simultaneous fitting to experimental mean ionic activity coefficient and liquid density data of strong electrolytes. Four strong electrolytes, three 1:1 and one 1:2 electrolytes have been used. Using adjusted ion parameters, osmotic coefficient of solvent has been predicted with 0.79% average relative deviation (ARD%). Results show that simplified SAFT, in combination with the MSA term has ARD% about 1% and less for correlating of density and mean ionic activity coefficient of electrolyte solutions.

In this study, the comprehensive review of empirical and analytical correlations, which are presented for estimation of the relative permeability of two-phase systems, is performed. 11 common and widely used correlations for modeling of two-phase flow of oil - water in porous media including the empirical correlations of Honarpour et al., Ibrahim & Koederitz and Al-Fattah and also those correlations which have adjustable parameters; such as, Corey generalized correlation, Brooks and Corey generalized correlation, Sigmund & McCaffery, Chierici, Van Genuchten-Maulem, LET, Ke and Li et al. were used. The accuracy of the above correlations was evaluated by using 644 experimental data points related to oil - water systems. Generalized Reduced Gradient nonlinear optimization method has been used locally and globally for determining the adjustable parameters of the parametric models. According to the performed adjustment and optimization, Sigmund & McCaffery and LET correlations showed the best agreement with experimental data of oil and water relative permeability, respectively. The decision tree for the best correlation to estimate the relative permeability in carbonate and sandstone rocks as well as for three states of wettability water-wet, intermediate-wet and oil-wet was presented. Also, due to the weakness of the correlations with adjustable parameters to be dependent on experimental relative permeability data in determining the values of their parameters, the best values of the parameters of these correlations were determined using global optimization on a wide range of experimental data. The results were reported for 4 correlations with the highest accuracy.

Undoubtedly, dew point pressure is a key parameter for determination of gas condensate phase diagram. Dew point prediction is a crucial issue for obtaining accurate performance of gas condensate reservoir. In this study, three empirical correlations are evaluated. These correlations are function of hydrocarbon components and non-hydrocarbon components, plus fraction and reservoir temperature. Next, the new hybrid correlation is developed as function Elsharkawy and Shokir correlations using 131 experimental data extracted from open literature. The results of new predicting correlation showed 11% improvement with respect to the best applied correlation Shokir.

A proper understanding of reservoir fluid phase behavior is the first crucial step in the development and production of an oil/gas field. This paper addresses the challenges and errors associated with the fluid sampling that may arise before, during and after the sampling operation. For this aim, DST and PVT data of exploration and production wells of a supergiant offshore gas condensate reservoir were analyzed. It was found that well conditioning and flow stability are essential before sampling. The main sources of error during the sampling include separator instability, lack of vapor-liquid equilibrium, volume ratio of separator outlets, and the presence of contaminants. Analysis of separator outlet streams further indicated deviation from equilibrium for some wells, which can have direct impact on dew-point pressure and condensate gas ratio (CGR) prediction of well stream. Improper fluid handling, oil and gas leakage, and the presence of corrosive compounds can severely affect the quality of the recombined fluid.

H2S and CO2 removal using alkanolamines is one of the most important processes which frequently used in industry. In this study, different amines were utilized for gas sweetening propose. Selecting appropriate amine directly effects minimization of energy consumption and expenses as well. Amine circulating rate and required energy for amine regeneration are the most important parameters for amine selection. In this regard, two types of amine with different concentrations were used. To reach desire separation, for this reason, DEA were used by of 25, 30, and 35 wt% concentrations, and DGA with 55, 60, and 65 wt% concentrations. Results showed that by increasing the concentrations of amine in amine solution, amine circulating rate and energy consumption were decreased. So, the best scenario is use of amines with highest possible concentrations. In addition, amine circulating rate was significantly decreased by replacing DGA in process. Thus, using 65 wt% DGA had the best results for gas sweetening process.

Properties and chemical composition of plus fraction in a petroleum fluid have a considerable impact on the fluid phase behavior. Understanding the trend of changes in molecular weight of successive single carbon number (SCN) groups in a plus fraction requires an accurate and reliable distribution function. Different distribution function models proposed so far may be applicable for certain types of reservoir fluids. In this work, analysis of 30 representative fluid samples in a supergiant gas condensate reservoir indicated a discontinuity in molecular weights of SCN groups at SCN=8, and SCN=13. The exponential, gamma, four-coefficient, and modified four-coefficient distribution functions were applied to these samples to predict the composition of SCN components. Results showed that the exponential distribution function does not predict the distribution of SCN composition accurately, especially in the aforementioned compositional discontinuities. Furthermore, the gamma distribution function was successful in predicting the jump in SCN=8 but failed at SCN=13. On the other hand, the modified four-coefficient model did predict the jumps in both SCN=8 and SCN=13. The overall error of calculations was 37.19%, 12.04% and 10.71% for exponential, gamma and modified four-coefficient models. Comparing four-coefficient and modified four-coefficient prediction results showed that the model parameters are strongly dependent on the fluid nature and need to be optimized based on available field data.

Usually, multiphase flow often occurs in producing wells of gas condensate reservoirs. Different correlations were proposed for predicting pressure drop in such reservoirs. However, no correlation or model is found to predict pressure drop in a wide range of operating conditions. In this paper, pseudo spontaneous potential logging (PSP) data measured at field conditions are used to compare the performance of different correlations in predicting pressure drop and liquid holdup in four gas condensate producing wells. Measured field data from four layer wells were used to tune the vertical lift performance (VLP) correlations and best correlations were recommended from matching between measured data and tuned correlations. Finally, measured wellhead pressure and gas flow rate were used to calculate and compare bottom-hole pressure from correlations of pipesim and after-before tuned correlations of prosper with minimum error. By comparing simulation results, Gray, from pipesim software and hagedorn & brown and petroleum expert2 correlations were found most accurate correlations for gas condensate wells from prosper sftware. Results of this study open a new screening criteria for selecting the best correlations to be applied in lean gas condensate wells.