فهرست مطالب reza mosayebi behbahani

The common view in the field of selling and transporting natural gas is that gas is produced, sold and transported according to market needs. But since gas is usually not consumed immediately after production, it needs to be stored before reaching the final consumer. Gas storage is essentially a means to store and supply it in order to regulate the energy market. Due to the access to storage facilities and the fact that the possibility of building tanks is not available for all market participants for several reasons, including the lack of economic justification. Therefore, the owners of the facilities enter into a contract with the storage customer. The main topic of this research is to examine legal obstacles and challenges of storage service contracts, especially in underground storage. In this research, knowledge of the components and content of storage services contract and the operational, commercial and legal principles that are required to conclude a contract are provided.

Natural gas consists of various hydrocarbons, all of which have their own economic values. Ethane recovery provides ethane, which is one of the most important petrochemical feedstocks. In this study, simulation and optimization of the ethane recovery process in Bandar Imam Petrochemical in Iran was investigated. Simulation of the entire plant was carried out using the HYSYS (V.10) simulator, and the Peng-Robinson equation of state was used to calculate the thermodynamic properties. Using process flow diagram data, the accuracy of simulation was examined. At first, performance of the plant was investigated, then two improved configurations for the plant were examined. Results show that the plant performance must be improved by feeding back the additional cold reflux bypassing the top stream of demethanizer tower through heat exchanger (first configuration) or by compressing the top products of demethanizer tower and passing it through Joule- Thomson valve (second configuration). The first configuration increased ethane recovery to 96.55%, which was due to 3.67% increase of reflux flowrate; the second one enhanced ethane recovery to 99.76%, which was due to 24.58% increase of reflux flowrate. Economic analysis proved that new configurations are cost-efficient.

One of the main problems in gas condensate wells occurring by increasing gas production and reducing pressure in gas condensate reservoirs is gas condensates loading and water in well, followed by reduced gas production and finally cut off gas production and condensates and extracted with gas from well. Thus, it is important to recognize the signs of liquid loading in the gas-producing wells in the initial stages and to provide a suitable solution for gas wells, and thus, to minimize the negative effects of fluid fall into the well opening. This paper examines the effect of various parameters on the liquid loading phenomenon in one of the well fields of Pazanan gas condensate. It was conducted to examine different factors and find the best solution for optimization in the studied wells. Finally, by providing the most suitable solution for the studied well, the rate of liquid loading in the studied wells is reduced and the economic profit resulting from optimization, high economic savings of this method and its efficiency are confirmed. Comparison of the results obtained from this study and simulation with Pipesim software shows that the results have a good accuracy for the new well completion and these results prevent liquid loading and optimizing and increasing production in the field studied at the current time and, ultimately, very high economic profit of optimizing and return on capital in the field studied.

In this study, supersonic nozzle is introduced as a high pressure system capable of separating condensate gas from natural gas. One of the most important advantages of this system is that the pressure recovery is largely in the divergent region of the nozzle during the shock wave phenomenon. On the other hand, the supersonic nozzle do not have rotating equipment and their use does not require energy. For modeling of supersonic separators, a series of nonlinear equations were solved numerically using MATLAB and HYSYS software. In this investigation, the effect of temperature, pressure and flow rate of feed inlet, return pressure on nozzle output and flow behavior inside nozzle are evaluated. The results of present work show that the selective separation of water and gas condensates by increasing the inlet pressure at constant temperature, increasing the inlet temperature at a constant outlet pressure and controlling the return pressure is feasible.

In this study, an equilibrium cell was used to measure the solubility of methane and ethane in pure water and aqueous solutions of sodium chloride and magnesium chloride in non-hydrate formation condition. Methane solubility measurements in pure water have been conducted at temperatures of (275/15 to 300/15) K and pressures of (20, 30 and 40) bar and for aqueous solutions of sodium chloride and magnesium chloride at temperatures of (275.15 to 290.15) K, pressures of (20 and 30) bar and molalities of (0.529, 1.092 and 1.692) mol/kg and (0.325, 0.670 and 1.039) mol/kg, respectively. Also, the solubility of ethane in pure water have been investigated at temperatures of (274/15 to 282/15) K and pressures of (2, 4 and 6) bar and for aqueous solution of sodium chloride at modalities of (1.901 and 3.020) mol/kg, temperatures of (273.15 to 278.15) K and pressures of (4 and 8) bar and for aqueous solution of magnesium chloride at molalities of (0.325 and 0.791) mol/kg, temperatures of (279.15 to 285.15) K and pressures of (4 and 8) bar. In addition, the thermodynamic models of Duan et al. and Mao et al. were used to calculate the solubility of methane and ethane gases in aqueous solutions of sodium chloride and magnesium chloride. The solubility of methane and ethane were found to decrease by increasing temperature and concentration, but with increasing pressure, the opposite behavior was observed. It can also be stated that the thermodynamic models showed good adaptation with experimental results.

One of the challenges of the exploitation and production of oil from reservoirs is the deposition of asphaltene particles on the transfer surfaces; such as, porous media, wells and piplines. Knowing about the particle size of asphaltene, in the studies of solid mass transfer of fluid to the surface, is essential to estimate the location, amount and time of the scale. One of the questions wich has been studied less is «How do the sizes of asphaltene particles change at different thermodynamic conditions?» In this study, asphaltene instability in one of the iranian heavy oil was determined by SARA test, initially. Thermodynamic behavior of asphaltene was found through filtration tests in high pressure and temperature conditions. Then, using an optical microscope, the sizes and distributions of the asphaltene particles were measured at 12 temperature and pressure points. The experimental results showed that both particle sizes and distribution of particles are sensitive to temperature and pressure. The thermodynamic and microscopic results are matched appropriately. Finally, the obtained experimental results were modeled in the form of an empirical correlation. The results of this study could be as an integrated chain between thermodynamic behavior of the asphaltene and the transfer phenomena of the asphaltene deposition in the oil well column and reservoir porous media.

In this study, an innovative approach is presented for modeling asphaltene deposition in the well column. The presented model predicts the time, location and amount of asphaltene deposited in the well column as a function of well, fluid and reservoir properties. The model is formulated based on thermodynamic equilibrium, heat transfer, mass transfer and empirical multi-phase flow equations. Asphaltene-containing oil is sampled from an oil well suffering from periodic deposition problems. The thermodynamic behavior of the oil and depositional characteristics of asphaltene have been determined via laboratory experiments and modeled accordingly using the Peng-Robinson equation of state and the modified solid model, respectively. The pressure profile in the well column was determined based on Duns and Ross two-phase flow model. The temperature profile in the well column has been determined based on a developed model derived from field measurements. Fluid flow and heat transfer equations have been solved simultaneously based on pressure and temperature profiles in the well column. The Escobedo-and-Mansoori model which has been used for mass transfer calculations was used to evaluate the rate of asphaltene deposition onto the wellbore at various depths. The simulated and reported field values of wellhead pressure and temperature were used for evaluation of model predictions. The model had over 95.5% and 99.1% accuracy in predicting the wellhead pressure and temperature, respectively, in a time window of over three months in the studied well.

Arguably, the natural gas transmission pipeline infrastructure in Iran represents one of the largest and most complex mechanical systems in the world. The optimization of large gas trunk lines known as IGAT results in reduced fuel consumption or higher capability and improves pipeline operation. In the current study, a single-objective optimization was conducted for Khormoj compressor station on the Iranian gas trunk line V (IGAT5). The system consists of over 504 kilometers of 56-inch pipeline from South Pars to Aghajari. This system passes through a tortuous terrain with changes in elevation which makes the optimization process even more challenging. Genetic algorithm (GA) was used in this optimization along with detailed models of the performance characteristics of compressors. The results show that in stations having the same compressor in parallel the minimum power (energy) consumption is reached when split flow in all the compressors is the same.

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.