Journal of Oil, Gas and Petrochemical Technology
سال ششم شماره 1 (Summer and Autumn 2019)

The investigation of the terminal falling velocity of non-spherical particles is currently one of the most promising topics in sedimentation technology due to its great signifcance in many separation processes. In this study, the potential of Artifcial Neural Networks (ANNs) for the prediction of nonspherical particles terminal falling velocity through Newtonian and nonNewtonian (power law) liquids was investigated using 361 experimental data. ANNs emerged as the most popular non-linear mathematical models due to their good prediction, simplicity, flexibility and the large capacity which moderate engineering endeavor, and the availability of a large number of training algorithms. The developed ANN model demonstrated the acceptable values for the prediction of terminal falling velocities such as the determination coefcient ( R2), MSE, and MRE which were equal to 0.9729, 0.0023, and 21%, respectively. In an investigation on terminal falling velocity and drag coefcient of spherical and non-spherical particles, it was found that the terminal falling velocity of non spherical particles to spherical particles was 0.1.

The distillation unit is one of the main units in refning companies, and it serves as the mother unit in any refnery with any degree of complexity. The optimization of this unit can increase productivity. In this study, the vacuum distillation unit of a refnery was selected as the case study. The shares of different expenses of this unit were clarifed using a novel material flow cost accounting (MFCA) method, the identifcation of the positive and negative products, and the identifcation of the actual values of the products. To this end, the vacuum distillation column was simulated by replacing Ahvaz’s crude oil with different types of crude oils such as Mansouri, and Maroon and also by combining these crude oils types. The results showed that the difference between the quality of Ahvaz crude oil products and Maroon and their combination was less than 2%, so it can be an appropriate alternative to the main crude oil, without changing the column operating conditions. The influence of changing the column conditions was also studied which revealed the zero effect of the variations of the quality of Mansouri’s crude oil products and its blend with Ahvaz crude oil. The feed temperature was changed 20 °C while the input and bottom column pressure increased 7 and 5 mmHg, respectively. But API varied from approximately 3 to 7 in the products. Finally, two types of Mansouri’s crude oil and a blend of Maroon and Ahvaz crude oil were introduced as the best alternatives to Ahvaz’s crude oil.

The present investigation was carried out to evaluate the application of Cloisite 30B organoclay (C30B) on the rheological, structural, electrical, and thermal characteristics of poly (methyl methacrylate)/multiwalled carbon nanotubes nanocomposites (PMMA/MWCNTs) fabricated by the simultaneous melt mixing. The microstructure and the state of nanofllers dispersion wereassessed by melt linear viscoelastic experiments, X-ray diffraction (XRD), and electron microscopy. The obtained results illustrated that the applied C30B nanofller considerably altered the pattern of MWCNTs dispersion and reaggregation. The study of electrical properties of single fller and hybrid nanocomposites also showed that the percolation threshold almost remained intact with the addition of C30B (φc ~0.18%), but an effective decrease in volume resistivity was observed at high MWCNTs loading levels. Finally, thermal analyses, employed as complementary experiments, confrmed that the MWCNTs dispersion was improved by the incorporation of C30B nanofllers.Upon the incorporation of nanofllers, a decrease in tanδ peak height and a small increase in Tg were observed. The Td,5%, Td,70%, and Tmax of the neat PMMA were 308, 342.9 and 335.2 °C, respectively while for the PMMA- 0.5%MWCNTs-3%C30B, they stood at 314.7, 380.3 and 369.2 °C, respectively.

Thermal recovery techniques including Fast-SAGD process increases the production efciency of heavy oil reservoirs. Effective parameters in this study included injection and production rates, height of the injection, production, and offset wells, production and injection cycles, and pressure of the offset wells. In this study, optimization studies were performed. The objective function was defned as the cumulative steam injection to the produced oil to recovery factor. As optimization studies is a time- consuming process, discretized form of effective parameters were applied in this study.Three methods of discretization were selected including linear, square, and logarithmic techniques and their results were compared. In this approach, discretization was based on the results of sensitivity analysis without the exact recognition of the reservoir parameters. Applying this technique, the optimization speed increased three times while the accuracy of the results remained constant. The difference between the optimization results in the continuous and discrete states was less than 3%. Moreover, simulation results of the fast-SAGD process with two cycles were presented in terms of RF, CSOR, temperature and pressure distributions, and the produced oil from SAGD and injected steam to the offset well.

A systematic study of two-staged upgrading process of vacuum residue for light fuel production has been carried out in a semi-batch binary reactor apparatus over Y, ZSM-5 and alkaline treated ZSM-5 zeolites. Prepared catalyst samples were characterized with XRD and BET. Density and Viscosity physical properties parameters estimation, as well as GC/SIMDIS analyses were conducted on liquid product to examine the quality of produced fuels. Solid residual product was observed with SEM pictures. Results of catalytic cracking of pyrolysis vapors revealed that liquid product viscosity was reduced by 40 wt% in the presence of alkaline treated ZSM-5 zeolite. Amount of naphtha+kerosene cut produced was elevated from 14.6% in the absence of catalyst to 21.68% over ZSM-5 and 31.4% over mesoporous ZSM-5 zeolite. In all the experiments 26% solid residue was remained in pyrolysis reactor which is desirable since preserves the catalyst from deactivation by heavy hydrocarbon molecules and coke precursors.

Hydrate formation in refinery gas pipelines is one of the major problems of refinery gas companies. There are a large number of investigations about this phenomenon. The neccessity of facing this problem has been considered in many cases. Some chemical methods and technologies have been used in order to inhibit the hydrate formation in pipelines or to predict it. In this study, a computational fluid dynamic (CFD) modeling was employed to predict the probability of hydrate formation in the gas pipeline. The proposed model was validated using the operational data of Ilam refinery gas pipeline. The pipeline was simulated and the results were compared with the experimental data. The obtained numerical results showed enough agreement with the experimental data. Regarding pressure gradient in the pipeline, hydrate formation temperature was calculated and the possibility of hydrate formation in the pipeline was evaluated according to the comparison between the hydrate formation temperature and the actual temperature. In addition, various parameters such as inlet temperature, ambient temperature, and gas flow rate were studied in order to find the hydrate formation probability using the sensitivity analysis method. Results showed that the inlet and ambient temperatures are usually higher than the hydrate formation temperature, so the probability of hydrate formation is low in the pipeline. Moreover, the results clearly showed that increasing the gas flow rate or decreasing the gas inlet temperature can increase the probability of hydrate formation in the pipeline.