مجله فرآیند نو
پیاپی 39 (پاییز 1391)

The gas injection such as CO2 injection is widely used for enhanced oil recovery (EOR). Moreover,in underground besieging of CO2 to decrease greenhouse gases or in the injection of CO2 to theunderground brine, we face the solubility of this gas in the aqueous salt solutions, so studying thesolubility of CO2 in aqueous salt solutions in the wide range of concentrations, pressures, temperaturesand different electrolytes is very important.In this article, the electrolyte cubic square-well (ECSW) equation of state of Haghtalab and Mazloumi,Fluid Phase equilibrium, is used for investigating the solubility of CO2 in aqueous binary solutionsof the different salts such as NaCl, KCl, Na2SO4, MgSO4, MgCl2 and CaCl2. The results demonstratethat the ECSW equation is able to obtain the solubility data of ternary aqueous salt electrolyte systems especially NaCl in pressures up to 400 bar with very good accuracy.

Nowadays, the accurate and fast simulation of the operational units such as distillation units to implement the changes, optimization and increase of their capacity have became possible with the specific simulation software of refinery processes such as Petro-SIM.In this article distillation unit of Bandar Abbas refinery was simulated in software Petro-SIM 4 and by using the results the required cases were evaluated in order to feasibility of the increase of Bandar Abbas Oil Refinery feedstocks and products by performing direct injection of sweet gas condensate to atmospheric tower of the distillation units.Finally, the most efficient mode of direct injection of gas condensates to atmospheric tower proposed. Also, by help of simulate conditions inside the tower and other parts distillation unit injection of liquid phenomena such as flooding, temperature gradient along the tower, the tower of the return flow, specification of outlet products, capacity of air coolers and pumps and other equipment, were determined The test field located in Bandar Abbas refinery distillation units currently ongoing. The most important achievements can be the increase of crude oil and gas condensate refine and increase in the production of strategic products such as gasoline and diesel.

Desalting Process is one of the most important steps of crude oil production plant in surface facilities andalso the first step of refinery units. Because of complex mechanism of this process, various aspects of theprocess still have been remained unknown. In this paper, it is attempted to obtain a more comprehensiveknowledge of its performance mechanism via introducing the various phenomena that happen in a crudeoil desalter. The fundamental principle of a crude oil desalter can be illustrated as the coalescence of smallwater droplets under the influence of an electrical field to form larger droplets that settle down more quickly.Furthermore, the influence of different operating conditions such as crude oil characteristics, temperature,electrical field strength, demulsifier concentration, and fresh water rate have been investigated using thegoverning equations in this phenomenon.

In this study for meter factor prediction, the bidirectional pipe prover performance has been simulated by CFD techniques in two velocities as 2 and 3 m/s for kerosene and two types of crude oil. Because of moving boundary condition, the simulations have been carried out with dynamic mesh. In the first stage of the simulation to have fully developed flow in the calibration section the prover pipe has been investigated without the sphere, next simulations has been repeated with ball in flow through the prover but with same conditions at the first stage. To achieve the lowest possible error, several simulations were conducted with two turbulence models: standard k- and k-. For validation, the CFD calculated pipe friction coefficient has been compared to empirical relations. The velocity distribution has been discussed for output crosssection and around the ball in prover. The results show that the effects of Reynolds number variation on meter factor are ignorable. Moreover, this work illustrates that CFD simulations is an inexpensive powerful tool for evaluation of prover performance. Also these simulations can be used for design of provers and detectors positions determination, etc.

Membrane contactor is a device which enables direct contact between gas and liquid phases without scattering in each other. Among several industrial and scientific examples, natural gas sweetening is the most important application of membrane contactor. Gas stream consists of natural gas, enters to the one side of membrane and absorbent phase flows in the other side. Membrane provides an interfacial surface which increases the rate of mass transfer between gas and liquid phases. Hollow fiber membranes utilized in membrane contactor should have hydrophobic surface property to prevent the liquid phase from penetrating to the porous structure. Otherwise, a huge increase in mass transfer resistance would be observed. In comparison to the conventional packed or tray towers, membrane contactor benefits from high interfacial mass transfer surface and very easy flow control as well as process operation. This article in addition to the application of mass transfer equations in simulation and modeling of membrane contactor; mainly focuses on the natural gas sweetening and analysis of the influential parameters on the performance and absorption process such as membrane wettability, liquefied absorbents, membrane characteristics and operational conditions.

Nowadays, isomerization process plays an important role in producing valuable products in different industries. These reactions are limited by thermodynamic equilibrium and reaching beyond the equilibrium conversion and high selectivity in conventional reactors is not achievable. Therefore, using new technologies such as membrane reactors, for increasing the efficiency of this process is necessary. In this paper, isomerization of linear and cyclic hydrocarbons in membrane reactors was investigated and their performance was evaluated in comparison with conventional catalytic reactors which consist from zeolite membranes MFI and zoelite catalyst, according to the results presented in literature. The obtained results showed that in these reactors, membrane plays a vital role in increasing the reaction rate, selectivity, better controlling of the reaction, reducing in energy consumption and increasing the final efficiency of the reaction.

Engine tests have an essential role in optimize, Simulate actual operating conditions and evaluation of performance of internal combustion engines fuels. In this tests, Standard and special engines are driven under certain conditions and adjustments in determined time. The Results used for optimizing of motor fuel formulation and improving of engines efficiency, minimize the engine problems (fuel sediments, soot and injectors fouling), promotion of fuel economy and Reduction of vehicles exhaust emissions. Engine tests are designed and defined based on the standards world or factory methods. High costs to inaugurate and enforcement the tests and difficult to prepare and security of spare parts of engines are barriers to their expansion. This paper has been paid to investigate and introducing of Engine Tests in quality evaluation of fuel of gasoline and diesel vehicles in Iran and other parts of the world.