Petroleum Engineering
Abdolah Golkari; Masoud Riazi; Amin Avazpour
Abstract
To provide supplementary oil recovery after the primary and secondary processes, enhanced oil recovery (EOR) techniques are introduced. Carbonated water injection (CWI) as an EOR method can improve sweep efficiency and the risk of gas leakage. On the other hand, the interfacial tension (IFT) is one of ...
Read More
To provide supplementary oil recovery after the primary and secondary processes, enhanced oil recovery (EOR) techniques are introduced. Carbonated water injection (CWI) as an EOR method can improve sweep efficiency and the risk of gas leakage. On the other hand, the interfacial tension (IFT) is one of the key factors which can affect fluid displacement during the process of CWI greatly. Therefore, the analysis of the IFT on an oil-carbonated water-CO2 system is vital. In this paper, the interfacial interactions of binary systems of asphaltenic crude oil (ACO), carbon dioxide (CO2), and carbonated water (CW) at different pressures and at two temperatures of 40 °C and 50 °C and their effects on the oil spreading in the water phase in the presence of gas are experimentally investigated. The IFT measurements were performed by axisymmetric drop shape analysis (ADSA) technique for the pendant/rising oil drop case. It is found out that the equilibrium interfacial tension (EIFT) of the two systems of crude oil-CO2 and water-CO2 is reduced almost linearly with pressure but increased with temperature. Moreover, the pressure has an increasing and decreasing effect on the water-oil and CW-oil IFT’s respectively. However, temperature has a reverse effect for the both systems. Spreading coefficient (SC) concept would help better understand the oil recovery mechanisms and potential. The results show that SC curve has a minimum point value as a specific pressure, which increases with temperature. The presence of CO2 in the water phase could strongly affect the oil spreading phenomenon through which oil recovery could be significantly enhanced.
Chemical Engineering
Gholamreza Roohollahi; Mohammadreza Ehsani
Abstract
Several mesoporous nickel-based catalysts with MgO-Al2O3 as the catalyst support were prepared using a co-precipitation method at a constant pH. The supports were prepared from the decomposition of an Mg-Al hydrotalcite-like structure which had already been prepared with Mg/Al=1. Prior to impregnating ...
Read More
Several mesoporous nickel-based catalysts with MgO-Al2O3 as the catalyst support were prepared using a co-precipitation method at a constant pH. The supports were prepared from the decomposition of an Mg-Al hydrotalcite-like structure which had already been prepared with Mg/Al=1. Prior to impregnating 10 wt.% nickel on the supports, the precursor was decomposed at several temperatures of 500, 600, 700, and 800 °C in order to elucidate the effect of calcination temperature on the physical and chemical characteristics of Mg-Al mixed oxides and the ultimate catalytic performance of the synthesized catalysts in the combined steam and dry reforming (CSDRM). The catalyst the precursor of which was calcined at 700 °C shows an excellent nickel dispersion and the highest activity among the other samples. It also exhibits the most stable performance during the long-term 36-hour run with high resistance against coke formation in the harsh condition of CSDRM.
Amirhossein Khalili-Garakani; Javad Ivakpour; Norollah Kasiri
Abstract
In the present work, the exergy analysis and economic study of 3 different samples of threecomponent mixtures have been investigated (ESI>1, ESI≈1, and ESI<1). The feed mixture has been tested under three different compositions (low, equal, and high contents of the intermediate component). ...
Read More
In the present work, the exergy analysis and economic study of 3 different samples of threecomponent mixtures have been investigated (ESI>1, ESI≈1, and ESI<1). The feed mixture has been tested under three different compositions (low, equal, and high contents of the intermediate component). A quantitative comparison between simple and complex configurations, considering thermally coupled, thermodynamically equivalent, and divided-wall column (DWC) has been carried out. The results present that the best sequence could be found by TAC or exergy loss rate analysis. Complex sequences have greater exergy losses in comparison to simple sequences. Despite expectations, the Petlyuk sequence only performs well in a few cases and poorly on others. According to the results, as the amount of intermediate component in the feed increases, both TAC and exergy losses of each sequence increase. The results also demonstrated that the occurrence frequency as the best sequence for DWC, thermodynamically equivalent, thermally coupled, and basic sequences are 36%, 28%, 25%, and 11% respectively. According to authors’ best knowledge, a quantitative exergy and cost comparison (based on rigorous simulation and optimization) between these configurations have never been carried out all together before.
Mechanical Engineering
Seyed Masoud Vahedi; Farzad Parvaz; Mohsen Khandan Bakavoli; Mohammad Kamali
Abstract
Separation of suspended droplets in a fluid flow has been a great concern for scientists and technologists. In the current study, the effect of the surface roughness on flow field and the performance of a gas-oil cyclone is studied numerically. The droplets and the turbulent airflow inside the cyclone ...
Read More
Separation of suspended droplets in a fluid flow has been a great concern for scientists and technologists. In the current study, the effect of the surface roughness on flow field and the performance of a gas-oil cyclone is studied numerically. The droplets and the turbulent airflow inside the cyclone are considered to be the discrete and continuous phases respectively. The Reynolds stress model (RSM) is employed to simulate the complex, yet strongly anisotropic, flow inside the cyclone while the Eulerian-Lagrangian approach is selected to track droplet motion. The results are compared to experimental studies; according to the results, the tangential and axial velocities, pressure drop, and Euler number decrease when the surface roughness increases. Moreover, the cyclone efficiency drops when the vortex length decreases as a result of a rise in surface roughness. The differences between the numerical and experimental results become significant at higher flow rates. By calculating the impact energy of droplets and imposing the film-wall condition on the walls, splash does not occur.
Chemical Engineering
Mehdi Ebnali; Mehdi Shahbazian; Houshang Jazayerirad
Abstract
Stripper columns are used for sweetening crude oil, and they must hold product hydrogen sulfide content as near the set points as possible in the faces of upsets. Since product quality cannot be measured easily and economically online, the control of product quality is often achieved ...
Read More
Stripper columns are used for sweetening crude oil, and they must hold product hydrogen sulfide content as near the set points as possible in the faces of upsets. Since product quality cannot be measured easily and economically online, the control of product quality is often achieved by maintaining a suitable tray temperature near its set point. Tray temperature control method, however, is not a proper option for a multi-component stripping column because the tray temperature does not correspond exactly to the product composition. To overcome this problem, secondary measurements can be used to infer the product quality and adjust the values of the manipulated variables. In this paper, we have used a novel inferential control approach base on adaptive network fuzzy inference system (ANFIS) for stripping process. ANFIS with different learning algorithms is used for modeling the process and building a composition estimator to estimate the composition of the bottom product. The developed estimator is tested, and the results show that the predictions made by ANFIS structure are in good agreement with the results of simulation by ASPEN HYSYS process simulation package. In addition, inferential control by the implementation of ANFIS-based online composition estimator in a cascade control scheme is superior to traditional tray temperature control method based on less integral time absolute error and low duty consumption in reboiler.
Petroleum Engineering – Reservoir
Behrouz Harimi; Mohsen Masihi; Mohammad Hosein Ghazanfari
Abstract
Gravity drainage is the main mechanism which controls the oil recovery from fractured reservoirs in both gas-cap drive and gas injection processes. The liquid bridge formed between two adjacent matrix blocks is responsible for capillary continuity phenomenon. The accurate determination of gas-liquid ...
Read More
Gravity drainage is the main mechanism which controls the oil recovery from fractured reservoirs in both gas-cap drive and gas injection processes. The liquid bridge formed between two adjacent matrix blocks is responsible for capillary continuity phenomenon. The accurate determination of gas-liquid interface profile of liquid bridge is crucial to predict fracture capillary pressure precisely. The liquid bridge interface profile in the absence and in the presence of gravity is numerically derived, and the obtained results are compared with the measured experimental data. It is shown that in the presence of gravity, fracture capillary pressure varies across the fracture, whereas, by ignoring gravitational effects, a constant capillary pressure is obtained for the whole fracture. Critical fracture aperture which is the maximum aperture that could retain a liquid bridge was computed for a range of liquid bridge volumes and contact angles. Then, non-linear regression was conducted on the obtained dataset to find an empirical relation for the prediction of critical fracture aperture as a function of liquid bridge volume and contact angle. The computation of fracture capillary pressure at different liquid bridge volumes, fracture apertures, and contact angles demonstrates that if the liquid bridge volume is sufficiently small (say less than 0.5 microliters), capillary pressure in a horizontal fracture may reach values more than 0.1 psi, which is comparable to capillary pressure in the matrix blocks. The obtained results reveal that the variation of fracture capillary pressure versus bridge volume (which represents liquid saturation in fracture) obeys a trend similar to the case of matrix capillary pressure. Therefore, the capillary pressure of matrix can be applied directly to fractures considering proper modifications. The results of this study emphasize the importance of capillary continuity created by liquid bridges in the performance of gas-oil gravity drainage in fractured reservoirs.
Chemical Engineering
Masoud Seidi; Mohsen Khezeli; Behrouz Bayati; Esmaeil Najafi
Abstract
In the current work, a framework is presented for amine solvent selection in gas treating process. Since the appropriate decision making in this field affects the capital and operational costs, multi attribute decision making (MADM) techniques were used to rank alternatives. The determination of criteria ...
Read More
In the current work, a framework is presented for amine solvent selection in gas treating process. Since the appropriate decision making in this field affects the capital and operational costs, multi attribute decision making (MADM) techniques were used to rank alternatives. The determination of criteria and alternatives is the most important aspect in the MADM. Criteria were divided into two categories, namely physical and process, and twelve physical indexes and nine process indexes were detected. Mono-ethanol amine (MEA), di-glycol amine (DGA), di-ethanol amine (DEA), di-isopropanol amine (DIPA), and methyl di-ethanol amine (MDEA) are intended as alternatives. The importance of the criteria was expressed by weights, and the weights were determined by the analytic hierarchy process (AHP) method. The traditional Technique for Order Preferences by Similarity to an Ideal Solution (TOPSIS) method was applied to the physical criteria with crisp data. The modified interval TOPSIS technique was used to study the process criteria with interval data. The data of the criteria and alternatives were collected from Ilam Gas Treating Company, and the solution for sour gas sweetening was ranked by the proposed approach. Based on our computations, MDEA was defined as the best amine solvent with an average ranking of 1.5.
Chemical Engineering
Iqbal Iqbal Hossain; Manos Roy; Abir Debnath
Abstract
Gasoline obtained from the fractionation of indigenous natural gas condensate has low octane number (78) and is therefore of limited uses. Lead-based octane boosting and catalytic reforming are not the viable methods for many fractionation plants. This study was therefore aimed to develop an inexpensive ...
Read More
Gasoline obtained from the fractionation of indigenous natural gas condensate has low octane number (78) and is therefore of limited uses. Lead-based octane boosting and catalytic reforming are not the viable methods for many fractionation plants. This study was therefore aimed to develop an inexpensive conceptual alternative method for boosting the octane number of gasoline. Natural gas concentrated in methane having high octane number (more than 100) was absorbed in the gasoline to boost the octane number partially (86). Selective additives i.e. ethanol, tert-butyl alcohol, methylcyclopentane, toluene, iso-octane and xylene were blended first with the gasoline to aid the absorption of natural gas molecules. The loss of absorbed gas molecules from gasoline with the increase in temperature was also observed. It is therefore required to try for avoiding any increase in temperature in the finished gasoline. The developed conceptual method is promising. The findings of this simulation study would be useful for more studies towards the development of an affordable alternative method for fractionation plants for boosting the octane number of gasoline derived from natural gas condensate.
Petroleum Engineering
Mohsen Seidmohammadi; Eghbal Sahraei; Behrouz Bayati
Abstract
Currently available polymers as a component of in-situ gels are unsuitable for treating high-temperature/high-salinity reservoirs due to their chemical and thermal degradation. In this study, a new copolymer-based gel system including high molecular weight nanostructured polymers (NSPs) was developed ...
Read More
Currently available polymers as a component of in-situ gels are unsuitable for treating high-temperature/high-salinity reservoirs due to their chemical and thermal degradation. In this study, a new copolymer-based gel system including high molecular weight nanostructured polymers (NSPs) was developed to address the excessive water production problem in reservoirs under harsh conditions. The stability of conventional polymer systems and NSPs was investigated under conditions of 40 days aging at 87000 ppm salinity and 90 °C. Then, gelation time optimization of gel systems composed of NSPs and chromium (III) acetate was performed with regards to the effect of copolymer concentration and copolymer/cross-linker ratio and their interactions during the gelation time. The central composite approach was used to design experiments and build a mathematical model. The analysis of variance (ANOVA) was used to estimate the deviation of the model predictions from the data. The results of stability analysis demonstrated the advantages of NSPs over conventional polymers by a viscosity reduction of 69, 36, and 18% for Flopaam3310, AN105, and NSPs respectively. The model developed for the prediction of gelation time of NSPs gel was significant at a confidence level of 98.6% against the test data. Moreover, it was found that gelation time became longer with a decrease in copolymer concentrations and/or increase in copolymer/cross-linker ratio.
Iman Mirzaie Goodarzi; Mansour Farzam; Mohammad Reza Shishesaz; Davood Zaarei
Abstract
The influence of increasing the SiO2/K2O molar ratio on the electrochemical action of a waterborne potassium silicate zinc-rich coating was investigated by means of electrochemical impedance spectroscopy (EIS) and corrosion potential (Ecorr) measurements. The EIS results showed that increasing the SiO2/K2O ...
Read More
The influence of increasing the SiO2/K2O molar ratio on the electrochemical action of a waterborne potassium silicate zinc-rich coating was investigated by means of electrochemical impedance spectroscopy (EIS) and corrosion potential (Ecorr) measurements. The EIS results showed that increasing the SiO2/K2O molar ratio in the range of 3.135 to 5 by the addition of nano-SiO2 to the resins improved the resistance of coatings; however, higher molar ratios showed an adverse effect. Moreover, the alkali silicate binder of the sample with a SiO2/K2O molar ratio of 5 was improved by adding 5, 10, and 15 wt.% of acrylic resin and acrylic/styrene copolymer to potassium silicate resin. These formulated coatings were sprayed over carbon steel plates and the adhesion and morphology of these primers were evaluated by pull-off, cross cut, and scanning electron microscopy tests. Electrochemical measurements showed that the sample with a SiO2/K2O molar ratio of 5 had better corrosion properties than the other samples. Adhesion and SEM tests also showed that B1 and C2 with respectively 5 and 10% acrylic derivatives had less holes, cracks, and better adhesive properties.
Petroleum Engineering
Mohsen Montazeri; Saeid Sadeghnejad
Abstract
Gas injection into carbonate formations is one of the most important activities to protect oil reserves that can guarantee a steady production. On-time injection of enough gas can result in the recovery of billions barrels of oil. In addition, it can preserve a huge amount of gas for the next generations. ...
Read More
Gas injection into carbonate formations is one of the most important activities to protect oil reserves that can guarantee a steady production. On-time injection of enough gas can result in the recovery of billions barrels of oil. In addition, it can preserve a huge amount of gas for the next generations. If the reservoir depth is shallow, or the reservoir fluid has a little amount of intermediate components, the flooding of rich gases is highly recommended. In the designing of a miscible injection process, firstly the minimum miscibility pressure should be measured or determined analytically. In this study, first the PVTi software is implemented to evaluate the miscibility of different injected gas, including carbon dioxide, nitrogen, methane, and different proportion of hydrocarbon gases. Subsequently, E-300 software is used to predict the recovery of the gas injection into the formation under study from one of the Iranian carbonate onshore fields. The investigation of the optimum injection rate as well as finding the proper layer of injection is investigated in details. The results show that the CO2 flooding after a long natural production period result in higher efficiency than the miscible injection of methane at the early stage of production.
Saeed Balouchi; Siyamak Moradi; Mohsen Masihi; Ali Erfaninia
Abstract
Fractured reservoirs contain about 85 and 90 percent of oil and gas resources respectively in Iran. A comprehensive study and investigation of fractures as the main factor affecting fluid flow or perhaps barrier seems necessary for reservoir development studies. High degrees of heterogeneity and sparseness ...
Read More
Fractured reservoirs contain about 85 and 90 percent of oil and gas resources respectively in Iran. A comprehensive study and investigation of fractures as the main factor affecting fluid flow or perhaps barrier seems necessary for reservoir development studies. High degrees of heterogeneity and sparseness of data have incapacitated conventional deterministic methods in fracture network modeling. Recently, simulated annealing (SA) has been applied to generate stochastic realizations of spatially correlated fracture networks by assuming that the elastic energy of fractures follows Boltzmann distribution. Although SA honors local variability, the objective function of geometrical fracture modeling is defined for homogeneous conditions. In this study, after the introduction of SA and the derivation of the energy function, a novel technique is presented to adjust the model with highly heterogeneous data for a fractured field from the southwest of Iran. To this end, the regular object-based model is combined with a grid-based technique to cover the heterogeneity of reservoir properties. The original SA algorithm is also modified by being constrained in different directions and weighting the energy function to make it appropriate for heterogeneous conditions. The simulation results of the presented approach are in good agreement with the observed field data.
Ali Khazaei; Hossein Parhizgar; Mohammad Reza Dehghani
Abstract
In this work, artificial neural network (ANN) has been employed to propose a practical model for predicting the surface tension of multi-component mixtures. In order to develop a reliable model based on the ANN, a comprehensive experimental data set including 15 ternary liquid mixtures at different temperatures ...
Read More
In this work, artificial neural network (ANN) has been employed to propose a practical model for predicting the surface tension of multi-component mixtures. In order to develop a reliable model based on the ANN, a comprehensive experimental data set including 15 ternary liquid mixtures at different temperatures was employed. These systems consist of 777 data points generally containing hydrocarbon components. The ANN model has been developed as a function of temperature, critical properties, and acentric factor of the mixture according to conventional corresponding-state models. 80% of the data points were employed for training ANN and the remaining data were utilized for testing the generated model. The average absolute relative deviations (AARD%) of the model for the training set, the testing set, and the total data points were obtained 1.69, 1.86, and 1.72 respectively. Comparing the results with Flory theory, Brok-Bird equation, and group contribution theory has proved the high prediction capability of the attained model.
Mohsen Esmaeili; Ali Heydarian; Abbas Helalizadeh
Abstract
Chemical flooding, especially alkaline/surfactant/polymer flooding, is of increasing interest due to the world increasing oil demand. This work shows the aspects of using alkaline/surfactant/polymer as an enhanced oil recovery method in the porous media having a high dead-end pore frequency with various ...
Read More
Chemical flooding, especially alkaline/surfactant/polymer flooding, is of increasing interest due to the world increasing oil demand. This work shows the aspects of using alkaline/surfactant/polymer as an enhanced oil recovery method in the porous media having a high dead-end pore frequency with various dead-end pore parameters (such as opening, depth, aspect ratio, and orientation). Using glass micromodels makes it possible to manipulate and analyze the pore parameters and watch through the porous media precisely. The results show that polyacrylamide almost always enhances oil production recovery factor (up to 14% in comparison with brine injection) in this kind of porous media. Except at low concentrations of polyacrylamide and sodium carbonate, sodium dodecyl sulfonate improves oil recovery (even 15% in the case of high polyacrylamide concentration and low sodium carbonate concentration). Increasing alkaline concentration reduces recovery factor except at low concentrations of polyacrylamide and high concentrations of surfactant.
Mohammad Golshadi; Reza Mosayebi Behbahani; Mohammad Reza Irani
Abstract
A computational fluid dynamic (CFD) study of methanol (MeOH) to dimethyl ether (DME) process in an adiabatic fixed-bed reactor is presented. One of the methods of industrial DME production is the catalytic dehydration of MeOH. Kinetic model was derived based on Bercic rate. The parameters of this equation ...
Read More
A computational fluid dynamic (CFD) study of methanol (MeOH) to dimethyl ether (DME) process in an adiabatic fixed-bed reactor is presented. One of the methods of industrial DME production is the catalytic dehydration of MeOH. Kinetic model was derived based on Bercic rate. The parameters of this equation for a specific catalyst were tuned by solving a one-dimensional homogenous model using MATLAB optimization module. A two-dimensional CFD simulation of the reaction is demonstrated and considered as numerical experiments. A sensitivity analysis was run in order to find the effect of temperature, pressure, and WHSV on the reactor performance. Good agreement was achieved between bench experimental data and the model. The results show that the maximum conversion of reaction (about 85.03%) is obtained at WHSV=10 h-1 and T=563.15 K, whereas the inlet temperature has a greater effect on methanol conversion. Moreover, the effect of water in inlet feed on methanol conversion is quantitatively studied. It was concluded that the results obtained from CFD analysis give precise guidelines for further studies on the optimization of reactor performance.
Saeed Mahmoodpour; Mohsen Masihi; Sajjad Gholinejhad
Abstract
The mathematical modeling of fracture networks is critical for the exploration and development of natural resources. Fractures can help the production of petroleum, water, and geothermal energy. They also greatly influence the drainage and production of methane gas from coal beds. Orientation and spatial ...
Read More
The mathematical modeling of fracture networks is critical for the exploration and development of natural resources. Fractures can help the production of petroleum, water, and geothermal energy. They also greatly influence the drainage and production of methane gas from coal beds. Orientation and spatial distribution of fractures in rocks are important factors in controlling fluid flow. The objective function recently developed by Masihi et al. 2007 was used herein to generate fracture models that incorporate field observations. To extend this method, simulated annealing, genetic, and tabu search algorithms were employed in the modeling of fracture networks. The effectiveness of each algorithm was compared and the applicability of the methodology was assessed through a case study. It is concluded that the fracture model generated by simulated annealing is better compared to those generated by genetic and tabu search algorithms.
Bizhan Khosronezhad Gheshlaghi; Mohammad Reza Dehghani; Hossein Parhizgar
Abstract
In this work, artificial neural network (ANN) was utilized to develop a new model for the prediction of the kinematic viscosity of petroleum fractions. This model was generated as a function of temperature (T), normal boiling point temperature (Tb), and specific gravity (S). In order to develop the new ...
Read More
In this work, artificial neural network (ANN) was utilized to develop a new model for the prediction of the kinematic viscosity of petroleum fractions. This model was generated as a function of temperature (T), normal boiling point temperature (Tb), and specific gravity (S). In order to develop the new model, different architectures of feed-forward type were examined. Finally, the optimum structure with three hidden layers was selected. The optimum structure had five, four, and two neurons in the first, second, and third layers respectively. To prevent over-fitting problem, 70% of the experimental data were used to train and validate the new model and the remaining data which did not participate in learning process was utilized to test the ability of the new model for the prediction of the kinematic viscosity of petroleum fractions. The results showed that the predicted/calculated and experimental data are in good agreement. The average absolute relative deviation (AARD) of the new model was 1.3%. Finally, the results were compared with an Eyring-based model (Soltani et al.’s work); it was shown that, based on the reported results by the authors, the accuracy of both model were in the same order.
Karim Salahshoor; Babak Roshanipour; Iman Karimi
Abstract
The current paper investigates the influence of packet losses in network control systems (NCS’s) using the model predictive control (MPC) strategy. The study focuses on two main network packet losses due to sensor to controller and controller to actuator along the communication paths. A new Markov-based ...
Read More
The current paper investigates the influence of packet losses in network control systems (NCS’s) using the model predictive control (MPC) strategy. The study focuses on two main network packet losses due to sensor to controller and controller to actuator along the communication paths. A new Markov-based method is employed to recursively estimate the probability of time delay in controller to actuator path and a generalized predictive control (GPC) method is proposed to compensate the effect of big network time-delay, which leads to packet loss. The proposed methods and algorithms have been evaluated using a practical Smar fieldbus pilot plant to judge the efficiency of the foregoing algorithms. The obtained results clearly demonstrate the superiorities of the proposed control scheme with respect to standard MPC algorithm.
Amir Hosein Tahershamsi; Ahad Ghaemi; Mansour Shirvani
Abstract
In this study, liquid-liquid extraction process in a Kuhni extraction column was modeled and simulated. A non-equilibrium dynamic model was developed for modeling liquid-liquid extraction processes based on a rate-based model. The model equations are inclusive of partial and ordinary differential equations ...
Read More
In this study, liquid-liquid extraction process in a Kuhni extraction column was modeled and simulated. A non-equilibrium dynamic model was developed for modeling liquid-liquid extraction processes based on a rate-based model. The model equations are inclusive of partial and ordinary differential equations which were discretized in column height direction. The population balance model was used for the calculation of droplet size distribution in the dispersed phase and the column hydrodynamic parameters. The equations were solved simultaneously through the finite difference method and the numerical method of lines. Experimental data on a bench scale Kuhni extraction column was used to evaluate the simulation results. The average correlation coefficient error of the mean diameter of the dispersed phase and mass transfer in various operating conditions are less than 2% 4 % respectively. A comparison between the experimental data and the simulation results proves the better productivity of the presented non-equilibrium dynamic model.
Tahereh Asadi; Mohammadreza Ehsani
Abstract
Copper trimesate (Cu-BTC) MOF has been pointed out as a promising adsorbent for separating carbon dioxide from methane. However, MOF’s need to be shaped prior to their use in packed bed adsorbers in order to reduce pressure drop; on the other hand, the production of mechanically resistant shaped ...
Read More
Copper trimesate (Cu-BTC) MOF has been pointed out as a promising adsorbent for separating carbon dioxide from methane. However, MOF’s need to be shaped prior to their use in packed bed adsorbers in order to reduce pressure drop; on the other hand, the production of mechanically resistant shaped bodies reduces their adsorption performance. In this work, Cu-BTC tablets provided by BASF are evaluated to perform CO2/CH4 separation through adsorption. The adsorption capacity of pure carbon dioxide from methane was measured in a magnetic suspension balance between temperatures of 308 and 373 K up to a pressure of 700 kPa. The evaluated material presents higher adsorption capacity than previously studied shaped samples with a carbon dioxide and methane adsorption capacity up to 3.07 and 0.63 mol/kg at 100 kPa and 308 K respectively. Moreover, the experimental data were fitted with the Langmuir model. Isosteric heats of adsorption were obtained to be 22.8 and 15.1 kJ/mol for CO2 and CH4 on Cu-BTC tablets respectively, which indicates a strong adsorption of carbon dioxide on these adsorbents. Also, single and binary breakthrough curves were measured in the same temperature range and atmospheric pressure by using Cu-BTC tablets as the adsorbent. The preferential adsorption capacity of CO2 on nanoporous copper trimesate (Cu-BTC) indicates that this material can be used for methane purification from natural gas.
Mostafa Sedaghatzadeh; Abbasali Khodadadi; Mohammad reza Tahmasebi birgani
Abstract
Designing drilling fluids for drilling in deep gas reservoirs and geothermal wells is a major challenge. Cooling drilling fluids and preparing stable mud with high thermal conductivity are of great concern. Drilling nanofluids, i.e. a low fraction of carbon nanotube (CNT) well dispersed in mud, may enhance ...
Read More
Designing drilling fluids for drilling in deep gas reservoirs and geothermal wells is a major challenge. Cooling drilling fluids and preparing stable mud with high thermal conductivity are of great concern. Drilling nanofluids, i.e. a low fraction of carbon nanotube (CNT) well dispersed in mud, may enhance the mixture thermal conductivity compared to the base fluids. Thus, they are potentially useful for advanced designing high temperature and high pressure (HTHP) drilling fluids. In the present study, the impacts of CNT volume fraction, ball milling time, functionalization, temperature, and dispersion quality (by means of scanning electron microscopy, SEM) on the thermal and rheological properties of water-based mud are experimentally investigated. The thermal conductivities of the nano-based drilling fluid are measured with a transient hot wire method. The experimental results show that the thermal conductivity of the water-based drilling fluid is enhanced by 23.2% in the presence of 1 vol% functionalized CNT at room temperature; it increases by 31.8% by raising the mud temperature to 50 °C. Furthermore, significant improvements are seen in the rheological properties—such as yield point, filtration properties, and annular viscosity—of the CNTmodified drilling fluid compared to the base mud, which pushes forward their future development.
Seyed Shamsollah Noorbakhsh; Mohammad Reza Rasaei; Ali Heydarian; Hamed Behnaman
Abstract
Reservoir models with many grid blocks suffer from long run time; it is hence important to deliberate a method to remedy this drawback. Usual upscaling methods are proved to fail to reproduce fine grid model behaviors in coarse grid models in well proximity. This is attributed to rapid pressure changes ...
Read More
Reservoir models with many grid blocks suffer from long run time; it is hence important to deliberate a method to remedy this drawback. Usual upscaling methods are proved to fail to reproduce fine grid model behaviors in coarse grid models in well proximity. This is attributed to rapid pressure changes in the near-well region. Standard permeability upscaling methods are limited to systems with linear pressure changes; therefore, special near-well upscaling approaches based on the well index concept are proposed for these regions with non-linear pressure profile. No general rule is available to calculate the proper well index in different heterogeneity patterns and coarsening levels. In this paper, the available near-well upscaling methods are investigated for homogeneous and heterogeneous permeability models at different coarsening levels. It is observed that the existing well index methods have limited success in reproducing the well flow and pressure behavior of the reference fine grid models as the heterogeneity or coarsening level increases. Coarse-scale well indexes are determined such that fine and coarse scale results for pressure are in agreement. Both vertical and horizontal wells are investigated and, for the case of vertical homogeneous wells, a linear relationship between the default (Peaceman) well index and the true (matched) well index is obtained, which considerably reduces the error of the Peaceman well index. For the case of heterogeneous vertical wells, a multiplier remedies the error. Similar results are obtained for horizontal wells (both heterogeneous and homogeneous models).
Ahmad Mousaei; Mohammad Ali Hatefi
Abstract
A value chain is a series of events that takes a raw material and with each step adds value to it. Global interest in the application of natural gas (NG) in production and transportation has grown dramatically, representing a long-term, low-cost, domestic, and secure alternative to petroleum-based fuels. ...
Read More
A value chain is a series of events that takes a raw material and with each step adds value to it. Global interest in the application of natural gas (NG) in production and transportation has grown dramatically, representing a long-term, low-cost, domestic, and secure alternative to petroleum-based fuels. Many technological solutions are currently considered on the market or in development, which address the challenge and opportunity of NG. In this paper, a decision support system (DSS) is introduced for selecting the best fuel to develop in the value chain of NG through four options, namely compressed NG (CNG), liquefied NG (LNG), dimethyl ether (DME), and gas-to-liquids (GTL). The DSS includes a model which uses the technique for order performance by similarity to ideal solution (TOPSIS) to select the best fuel in the value chain of NG based on the attributes such as market situations, technology availability, and transportation infrastructure. The model recommends some key guidelines for two branches of countries, i.e. those which have NG resources and the others. We believe that applying the proposed DSS helps the oil and gas/energy ministries in a most effective and productive manner dealing with the complicated fuel-related production and transportation decision-making situations.
Management
Abbas Alimoradi; Sepideh Borzoupour
Abstract
In the present business atmosphere, an organization should be able to respond to environmental needs occasioned by rapid and dynamic evolution as quickly as possible. It is obvious that such ability is impossible without a proper strategic approach, strategic thinking, and a suitable management accounting ...
Read More
In the present business atmosphere, an organization should be able to respond to environmental needs occasioned by rapid and dynamic evolution as quickly as possible. It is obvious that such ability is impossible without a proper strategic approach, strategic thinking, and a suitable management accounting system. This study attempts to investigate the relationships between strategy, management accounting systems, and the performance of Iranian petrochemical companies under the framework of contingency theory. It is assumed that matches between organizational strategies and the content variables of organizational structure in controlling environments such as management accounting systems could produce an optimal level of performance. The statistical population of the study is Iranian petrochemical private companies, and the required information has been gathered by questionnaire the internal reliability of which is confirmed by a Cronbach's alpha coefficient of 83.4%. Structural equation modelling with LISREL software has been used for data analysis and hypotheses testing. The results not only confirm the direct association between strategy, management accounting systems, and company performance, but also support the effect of management accounting system as a mediating variable on the relationship between strategy and performance. According to the results, it might be concluded that contingency theory postulates are applicable to the Iranian petrochemical industry, and this conclusion may shed some light on the way in which these companies are managed and controlled.
Fatemeh Amin; Ali Reza Solaimany Nazar
Abstract
The Taguchi design of experiments (DOE) approach is adopted here to evaluate the impact ofeffective factors such as nanoparticles type, nanoparticles to model solution mass ratio, asphaltenestructure, and temperature on asphaltene adsorption equilibrium. Herein, the toluene-asphaltenesolution model is ...
Read More
The Taguchi design of experiments (DOE) approach is adopted here to evaluate the impact ofeffective factors such as nanoparticles type, nanoparticles to model solution mass ratio, asphaltenestructure, and temperature on asphaltene adsorption equilibrium. Herein, the toluene-asphaltenesolution model is applied. Three commercially nanoparticles (SiO2, Al2O3, and TiO2) are used.Asphaltene characterizations are carried out by X-ray diffraction (XRD) analysis. It is found that thenanoparticle type and asphaltene structure with a respective influence of 48.5% and 3.11% have themaximum and minimum contribution on the amount of adsorbed asphaltene at the selected levelsrespectively. Aluminum oxide nanoparticle has the maximum and silicon oxide nanoparticle showsthe minimum adsorption. The temperature has no statistical significance. Asphaltenes with higheraromaticity have more tendencies for adsorption on nanoparticles.
