نشریه فناوری های نوین در سیستم های انرژی
سال دوم شماره 3 (پیاپی 203، پاییز 1395)

This paper propose is deliberation of tert-amyl-methyl ether (TAME) production and ‎separation process as an gasoline additive to improve the octane number. According to ‎the environmental impact of other gasoline additive like MTBA, it's important to use ‎another compounds that are environmentally friendly like TAME. In the previous ‎studies, methanol was recovered with water in TAME production process. In this paper ‎reveals new possibility to use pressure swing instead of using water to separate ‎methanol from C5 and other hydrocarbons. To underline process characteristics, two ‎case studies with those different configurations are presented and analyzed using ‎Aspen HYSYS 8.6. In the first case study, classical methanol separation using water ‎extraction is considered. The second case study is based on pressure swing distillation ‎to separate the zoetrope’s between hydrocarbons and methanol. In both case studies ‎the TAME production section are similar and the difference is on the methanol ‎separation section.‎ Results show that use of pressure swing in methanol separation section of this process, ‎doesn't need water and reduced the annual cost till 4 percent.‎

Three-dimensional simulations are presented on the motion of a bubble between two parallel plates at a finite Reynolds number in a combined couette-poiseuille flow. The full Navier-Stokes equations are solved by a finite difference/front tracking method on a regular, fixed and staggered grid. Interface is tracked explicitly by connecting marker points on an irregular, triangle and moving grid. The interface effects are accounted for by adding appropriate source terms into the governing equations. The effects of the dimensionless numbers, such as, Capillary number, Reynolds number, and geometric ratio on the lateral migration of a bubble are studied in detail. Simulations also show that the bubble deformation depends strongly on the Capillary number. So that, the proper non-dimensional number for the interfacial tension is the Capillary number. As the radius of the bubble increases, the equilibrium position moves closer to the centerline. Then, the gravity force was added. Bubbles are more deformed with increasing the Bond number and move to an equilibrium position closer to the centerline.

The increasing concentration of the carbon dioxide greenhouse gas in the atmosphere has caused the concern and pressure of the international community to reduce and control for emissions of the gas. The separation of carbon dioxide attracted considerable attention in recent years in order to control its dissemination in the waste gases and exhaust gases of chimneys. In this regard due to the advantages of membrane technology in gas separation, the permeability properties of a new type of polyurethane membrane have been evaluated and compared on two basis of polyether poly tetra methylene glycol polyester poly caprolactone. Membranes were made by using the method of casting solution and the differential scanning calorimetry technique has been used to determine the thermal properties and glass transition temperature of membranes. As well as, permeability and selectivity properties of membranes were examined by helping the throughput test of pure gases. Experiments were carried out at different pressures in temperatures of 25 ° C. Based on the test results, the permeability of carbon dioxide gas and nitrogen gas decreased with increasing the pressure on both types of membrane, and selectivity of the carbon dioxide to the nitrogen increased. Also the polyether-based membrane was introduced as superior membrane for gas separation of carbon dioxide/nitrogen in the comparison between two types of membrane according to the Robson curve.

Many industrial process like oil refining, food industry, mining and environmental cleanup are included separation of solid particles from gas stream. Vortex separators also called cyclone separators which are widely used in order to collect dust and particles from industrial gas flow that have been considered due to the simple structure, low operating space requirements and also the ability to function in harsh operating conditions. However, in the best operating conditions, it has not a desirable yield. Due to the cyclone’s function, several methods have been examined in order to increase its efficiency. One of the most effective methods is to use spiral concentrator. In this study, the goal is to evaluate the effect of the output clean gas embedded valve geometry in separation efficiency in spiral concentrator, which included some tests to survey effective parameters such as angle, length connection status and also primary and secondary flow. The results indicate that the efficiency of the concentrator has a direct connection to the length of the output valve and reverse connection to the angle. Thus, by increasing the output length and decreasing its angle the amount of absorbed dust is reduced, which indicate the rising of the concentrator’s efficiency. In this study, the highest achieved efficiency is 99.82%. This spiral concentrator can easily be used in industrial matters.

In this research for the first time, dealuminated (acid treated) natural clinoptilolite zeolite was used for the total oxidation of toluene. The chemical modification of the zeolite is conducted by acid treating, ion-exchange and calcination methods. Then catalytic behaviour of the sample was investigated using the integral fixed bed catalytic reactor. In this work, the effect of variables such as reactor temperature, flow rate of pollutant and extent of dealumination was evaluated. The dealuminated clinoptilolite zeolite showed a promising performance for toluene abatement via total oxidation of toluene so that temperature corresponding to the maximum activity (100% conversion of toluene) was shifted to lower temperature (300 °C).