نشریه مهندسی گاز ایران
پیاپی 12 (پاییز و زمستان 1399)

In this study, the hydrogen purification section of the catalytic reforming unit of Abadan Oil Refining was simulated by Aspen Hysys v9.0. The check of the simulation results of the unit compared to the actual data represent the mean total error of 0.9 %, which indicates the high accuracy of the simulation by choosing the SRK thermodynamic model. The unit reactor was optimized by the use of Case Study and the effect of various parameters such as temperature, the pressure of feed and also the hydrogen discharge ratio on the quality of the product was investigated. The results showed that the increase in temperature and pressure of feed have a positive and neutral effect on desulfurization reactions, respectively. The increase in discharge ratio of hydrogen also has a negative effect on the quality of the product due to the decrease in residence time and incomplete reactions in the reactor. Also, the unit energy was optimized by Aspen Energy Analyzer v9.0. In this modified method, two heat exchangers with areas of 18.6 and 9.9 square meters were added prior to stripper column as feed preheat and naphtha inlet to the separator in the unifing unit. That decreased the heat load of stripper column reboiler and the unit furnace by 3.38 and 3.82 MMBtu/hr, respectively. As a result, this plan needs 30,529.35$ worth of investment. Therefore, the return of capital of this plan was estimated to be 35 months which will result in a 10,447.87$ saving.

After recognizing the toxic and carcinogenic effects of Lead organic compounds, production of compounds such as Methyl tertiary butyl ether as an additive to ordinary hydro carbonate gases was proposed. These materials are able to enter into water, soil and air due to relative steam pressure and partial dissolution in water and cause the pollution. As a result, development of a new process for producing gas with high octane from complex compounds of light petroleum distillates was initiated. This method is based on separating C5-C8 linear and branched alkanes according to their absorption properties, chain length and the number of branches. In this study, the hybrid neural network model based on experimental data in the database has been used as an alternative model for predicting the separation rate of linear and branched paraffin through absorption process. Absorption temperature, absorption time, hydrocarbons' octane number, and hydrocarbon density are considered as four input parameters, and the ratio of linear paraffin concentration to total (C/C0) as the output parameter of neural network. The neural network model was successfully generalized by experimental database and then was investigated with the help of test data. The results of modeling for the test data indicated the success of neural network model in predicting the rate of linear paraffin separation from non-linear ones. Therefore, the developed neural network model can be used for determining the C/C0 with confidence in absorption process. According the obtained results for test data, the minimum mean squared error is 0/0518, which is a satisfactory measure. The model and experimental data were compared and regression coefficient 0.990 shows good matching between modeling results and experimental results.

Studies show that the maximum energy consumption in future years would be natural gas. Increasing gas consumption and peak of consumption in cold seasons make natural gas storage crucial to prevent future crisis. Underground storage is considered the best storage method for this purpose. The purpose of this paper to investigate the necessity of underground gas storage construction Razavi Khorasan Province. Razavi Khorasan Province is one of the areas where the cold period is relatively longer in comparison with other regions. This province is far from oil-rich regions of the country and the area is supplied with fossil fuel through pipelines (for gas) or road transport (for oil). Both transmission systems lack a high safety factor and are not considered reliable fuel-supply systems for the region in case of disaster. Evidence for this claim is the problems and hardships caused by the fuel supply in the unprecedented cold of the 2007 winter. To do this, natural gas consumptions of Razavi Khorasan Province within last years were evaluated and consumption methods in different months were also investigated. Our studies show that during cold months, Razavi Khorasan Province encounters gas shortage and therefore, underground storage of natural gas can be a proper and economic solution.

In the present research, to plan the future of Iran's potential helium reserves and identify ‎important target markets, the status of resources and reserves, production, consumption and ‎global trade of helium has been statistically investigated during a period of 10 years (2010-2019). ‎In this regard, by extracting data from valid international statistical sources and references, ‎processing and drawing diagrams and analyzing them, the position of the world's leading ‎continents and countries in various fields was determined. The results of the research show that ‎most of the world's helium sources are in the United States of America, Qatar, Algeria and ‎Russia. The United States and Qatar also supply much of the world's helium. The average global ‎production of helium is about 175 million cubic meters per year, where moderately the United ‎States, 55%, Qatar, 32%, Algeria, 6%, Australia, 3%, Russia, 2%, Poland, 1% and the rest of the ‎world countries, perform 1% of global helium production. In terms of helium consumption, the ‎continents of America, Asia, Europe and Africa were ranked respectively. The United States of ‎America, Japan and China have the highest helium consumption in the world, respectively. Asian ‎countries China and Japan are major importers and some countries in the Middle East are also ‎importers of helium, which can be focused as export target markets. The world's largest exporters ‎of helium are the United States of America, Qatar, Algeria, France, Russia, Australia and the ‎United Arab Emirates, respectively. Therefore, in the future, Iran's main trade competitors in the ‎field of helium exports will be Qatar, Russia and Australia countries which, with logical and ‎correct planning, should overtake them and seize the target export markets.‎

One of the most common ways to use flare gases is to convert it into valuable products such as gasoline and other products. process of gas transformation to gasoline(FGTG), consist of 5 units: 1) gas sweetening unit, 2) sulfur recovery unit, 3) synthesis gas production unit, 4) methanol synthesis unit, 5) methanol conversion to gasoline unit. simulating different scheme of (FGTG) process aiming to reduce greenhouse gases, increasing productivity and reducing energy consumption and effective operational parameter sensitivity analysis one of the important goals of this literature. Suggested New schemes for conversion of flare gas to gasoline, in order to reduce greenhouse gases and increases of productivity, a Combined membrane–reverse water gas shift reaction unite(Membrane + RWGS) or reverse water gas shift reaction unite membrane without separation (RWGS) recommended besides of (FGTG) unit. Finally, the basic model layout will be compared with the two new ones. By sensitivity analysis, it was found that the FGTG process with the Combined membrane–reverse water gas shift reaction unite has the highest product yield and the highest energy consumption compared to other compositions.

Oil-associated salts, depending on their origin, usually contain sodium, potassium, and magnesium. One of the best and most effective ways to separate salt water from crude oil is to use an electrostatic field. In this method, the droplets are polarized in the presence of an electric field and an electrostatic force is created between them, which causes the droplets to approach and coagulate. Using an electric field, the coagulation rate of a dispersed phase in an emulsion can be increased. Therefore, methods based on electric current have been proposed. From an energy efficiency point of view, electrical separation is the best way to break the emulsion and desalinate the oil. Therefore, an electric current is used when the salt water droplets are difficult to separate from the oil. The basic principles of electrostatic desalination of crude oil can be summed up as the application of small droplets of water under an electric field and the formation of larger droplets of water with higher settling velocities.

The nucleation process in solid natural gas storage is one of the key steps in the storage capacity and stability under environmental conditions. The gas storage conditions can be improved by controlling this stage. In this research, we tried to use nonporous materials In order to obtain the thermal properties of nanoparticles in the stability of solid gas and use of its porosity in nanoscale dimensions to increase the storage capacity. Therefore, the use of pure and functional nanoparticle graphene into nanofluid was evaluated and the results were compared with each other. The gas solidification process was carried out at a concentration of 1% wt. of graphene at 1000 psig and 4 °C.The results were compared with a control sample containing water/surfactant and a pure water sample, and it was observed that the functionalizing process by removing surfactant would ultimately lead to better performance. Graphene itself reduced the process of dissolution by 67.2% and induction time to 71% and increased the storage value by 67%.It is also seen that the graphene nanoparticulate plays the same role in storing gas as surfactant, with the difference that it increases stability. This is while surfactant decreases this stability and increases the rate of gas dissolution.