مجله فرآیند نو
پیاپی 47 (پاییز 1393)

In this study various empirical، theoritical and semi-theoritical equations of state for different optional fluids، have been investigated and the accuracy of these equations for thermodynamic properties estimation of these fluids in comparison with experimental data، was evaluated. Also a new equation of state has been derived from Mohammadikhah-Abolqasemi-Mohebbi semi-theoretical equation and has been introduced. The results of this research have showed that assumed equations of state have good accuracy in predicting the enthalpy and entropy for pure fluids in atmospheric pressures and slightly higher، except for n-butane which the error was high. Also، results of this research have showed good agreement between calculated data from these equations for compressibility factor prediction of optional fluids with experimental data. Also soave-redlich-kwong equation of state has been recommended for calculating thermodynamic properties including enthalpy and entropy at low pressures، because it has showed minimum errors.

In this research some aspect of temperature control in pilot reactor was investigated. The split flow mode procedure was proposed، in which the temperature of feed gas، containing methane and oxygen، were reached to favorite reaction temperature before entrance to reactor. For the reason of highly exothermic of partial oxidative reaction، the important problem will be removal of heat flux from reactor body. In this research reactor was exposure in heat transfer with environment through radiation and convection. The passing of gas through the packed bed was used for reaching feed gas temperature to the optimum range. In this way OCM reactor was performed in isothermal operation and has high potential for heat removal. The reactor designed for diameter of 1 in and length of 125 cm.

Hydrogen liquefaction process is a complex operation due to the special equipment and operational conditions used. The challenges involved are classified into three divisions as follow: high costs، low efficiency، and lack of the development of new approaches to produce liquid hydrogen. The peculiar nature of molecules of hydrogen، particular operational conditions of the hydrogen liquefaction process، and the use of appropriate equipment and materials operated under these conditions، cause many obstacles in the development of liquid hydrogen production. In the current study، a review on the challenges of the liquefaction of hydrogen is presented and appropriate solutions are suggested for each of them.

Due to increased demands on lubricants، there is a need to develop new lubricants and improved additives. Ionic liquids (ILs) are room temperature molten salts that have recently shown many advantages in this area. The application of ILs as lubricants in a diverse range of systems has found that these materials can show remarkable protection against wear and reduction of friction. ILs consists of large asymmetrical ions that can readily adsorb onto a metal surface and produce a protective film under boundary lubrication conditions. This article starts with a brief introduction to ILs and fluid lubrication، and then discusses in more detail the tribological properties of IL lubricants، either as base and synthetic oil additives. In this article the correlation between the IL structure and their performance in tribology applications is examined. Finally، some current problems and potential solutions are discussed.

Nowadays، natural gas reforming by steam is and important technique for hydrogen production. According to the fact that reaction of hydrogen production is an endothermic reaction، high energy consumption is required. In this research، the effect of operating temperature of furnace reformer unit in various capacities on productive efficiency and energy consumption of this unit was studied. Also an appropriate procedure was recommended for optimization of furnace reformer temperature. The obtained results showed that in a special capacity by decreasing of furnace reformer temperature up to 10 oC the consumed fuel was declined up to 200 NM3/h whereas the outlet stream located in standard specifications. Also results exhibited linear trend for the optimization.

The petroleum and petrochemical industries produce considerable amounts of spent catalysts. The platinum group metals (PGMs) exhibit excellent catalytic activity. Their excellent selective and activity make them very effective catalysts. Catalysts, after a certain period of active life and regeneration cycles, are deactivated. The aim of the present study is to introduce and compare the wet-base (hydrometallurgy) methods used for extraction of platinum from spent catalysts. First, the principles of wet method and its kinds are introduced. Then, the previous experimental studies in which the extraction of platinum from autocatalysts and spent catalysts of chemical industries has been studied, are reviewed and compared in terms of operating conditions, materials, economic and environmental aspects.