Journal of Oil, Gas and Petrochemical Technology
سال دوم شماره 1 (Winter and Spring 2015)

A key parameter for the application of polymer gels in water shut off treatment is the adsorption of polymer gel onto the rock surface. So, the adsorption properties of a nanocomposite hydrogel were discussed in this research by crosslinking of sulfonated polyacrylamide/sodium montmorillonite aqueous solutions with chromium triacetate. The X-ray diffraction patterns indicated that exfoliated type of microstructure was formed. In addition, fourier transform infrared spectroscopy was used to prove the nanocomposite hydrogel interacted with the rock surface qualitatively and the scanning electron microscopy to determine the surface characteristics of the nanocomposite hydrogel layer adsorbed on powdered rock surface. The general behavior of the response indicated that in comparison with the pressure, the adsorption is much more sensitive to the S/L ratio change. The addition of nanoclay of Na-montmorillonite increased the adsorption of NC hydrogel on the surface of powdered sandstone. The influence of pressure and solid/liquid ratio was investigated on adsorption amount. The results showed that nanocomposite hydrogel adsorption decreased continuously by increase of solid/liquid ratio while its adsorption was almost independent of the pressure. Besides, the maximum amount of nanocomposite hydrogel adsorption was obtained in 2500 psi pressure and 0.005 ratio of solid/liquid.

In this study, artificial neural network was used to predict the surface tension of 20 hydrocarbon mixtures. Experimental data was divided into two parts (70% for training and 30% for testing). Optimal configuration of the network was obtained with minimization of prediction error on testing data. The accuracy of our proposed model was compared with four well-known empirical equations. The artificial neural network was more accurate as the result showed that while standard deviation of ARD for artificial neural network was 3.63001, the standard deviation of ARD for Brock and Bird, Pitzer, Zuo-Stenby and Sastri-Rao models were 23.77569, 18.44848, 13.00388 and 9.63137 respectively.

In the present study, the potential of a bacterial consortium of Enterobacter cloacae and Pseudomonas sp. (ERCPPI-2) for microbial enhanced oil recovery was investigated. Various mechanisms of enhanced oil recovery (EOR) as a result of using ERCPPI-2 and its metabolic products were studied in detail. The obtained results showed that under simulated reservoir conditions, interfacial tension reduction (IFT), gas production and wettability alteration were the main mechanisms for more oil recovery from the water-flooded cores. It was also found that biosurfactant production had a substantial effect on the reduction of oil/water interfacial tension and recovering the trapped oil.  The experimental data acquired from the designed core holder flooding system demonstrated that in situ bacterial growth altered the wettability of cores towards more water-wet conditions while the cell-free biosurfactant injection reversed it into more oil-wet conditions. Due to the effect of multiple microbial mechanisms exerted by ERCPPI-2, bacterial injection was able to reduce the residual oil saturation below 3%, in spite of its amount at the beginning of microbial process. In more severe conditions of a salinity of 5% (w/v) and temperature of 60 °C, the oil recovery efficiency reached 24.1 and 39.1%, respectively.

The simplified perturbed chain statistical associating fluid theory (sPC-SAFT) Equation of State (EOS) was proposed to describe the thermodynamic properties of pure ionic liquids (ILs). A set of sPC-SAFT parameters for 2 ILs was obtained by fitting the experimental liquid densities data over a wide range of temperature at atmospheric pressure. Good agreement with experimental density data was observed at both atmospheric and high pressure when ILs were considered as an association compound with various association schemes or a non association compound .Then, the solubility of CO2 in 1-alkyl-3-methylimidazolium tetrafluoroborate ILs was studied over a wide range of temperatures and pressures. For such binary systems, the binary interaction parameter was used by fitting to experimental vapor-liquid equilibrium data. This parameter is temperature-dependent and has linear correlation with temperature. In all cases, good agreement between sPC-PSAFT correlation and experimental data for these binary mixtures was observed.

For more than three decades, Oxidative Coupling of Methane (OCM) process has been comprehensively investigated as an attractive alternative for the commercially available ethylene production technologies such as ethane and naphtha cracking. Developing a suitable catalyst and proper reactor feeding policy, reviewing and deploying the efficient methods in the separation and purification of the undesired and desired products, possible energy saving and process intensification in different sections of the OCM process, each has been the subject of many researches in the past. In this paper, the interconnections of these aspects will be addressed by reviewing the performance of different alternative structures and unit operations in different sections of the OCM process. As a systematic approach in this analysis, a concurrent engineering approach supported by the experimental data which was extracted from an OCM miniplant scale facility was applied. Using an efficient porous packed bed membrane reactor and a proper set of operating conditions, up to 25% C2-yield, 20% C2H4-yield, and 52% C2H4-selectivity and the highest observed fluidized bed reactor C2-yield was achieved in this OCM miniplant. This experimental analysis was performed in the chair of process dynamics and operation at Berlin Institute of Technology under the main framework of Unifying Concepts in Catalysis (UniCat) project.  The economic analysis of the industrial-scale operation showed promising potentials and also advantages of the final proposed OCM process-structure in this research.

In this study using Equation of State/ Helmholtz excess energy function,  EOS/AE, two new local composition-Equation-of State mixing rules, LCEOS1 and LCEOS2 were developed in which the energy interaction parameters were expressed in terms of attractive and repulsive parameters of the cubic equation of state. The EOS/AE models are applied for equilibrium calculation of natural gas that consists of light to heavy hydrocarbons with water and acid gases, i.e. H2S and CO2. Applying these new mixing rules, the bubble point pressure and vapor phase compositions at high pressure were simulated. The binary interaction parameters and a lumped nonrandomness parameter for the binary systems containing CO2, H2S, H2O, CH4, C2H6, EG, TEG were obtained. Using the binary parameters, solubility of CH4 and C2H6 in ternary systems CH4+EG+H2O and C2H6+EG+H2O were predicted, respectively. A comparison of these two new mixing rules with experimental data showed that both LCEOS1 and LCEOS2 demonstrated high accuracy.