دوماهنامه مهندسی شیمی ایران
پیاپی 17 (امرداد و شهریور 1384)

Aluminum exits as a bauxite ore. It must be first crushed and then by optimizing parameters such as temperature, leaching time, ration of solid to liquid, acid concentration and bauxite powder particles, it is washed with sulfuric acid (optimum here means the lowest ratio of). The next step, ethanol is used to purify alum and control the rate of iron. Then with solvent extraction, iron III in the solution is reduced to the lowest amount. The main aim of this work is to introduce a way to control iron from leaching to extraction process and to investigate the important parameters in the extraction process. In addition, to introduce the cheapest extractor and dilutor without using expensive additives in this method.

In this work a developed model has been introduced for oil extraction from oil seed in a continues fixed bed system.. An analytical solution has been obtained for this model using separation variable method. As an important result the diffusion coefficient of oil in the solvent is the only parameter of this model. This parameter has been obtained experimentally for canola seed in methylen chloride solvent. The distribution of oil concentration and amount of oil extraction can be obtained by this model.

Since the start of the industrial production of fertilizers about one hundred years ago, the fertilizer industry has made tremendous progress in developing ever more efficient fertilizers and improved production methods.In spite of these improvements certain problems are still encountered in the manufacture, handling and application of industrial fertilizers. The main problems can be listed as caking, dusting and moisture pick-up, and have attracted a great deal of attention in the past, but although progress has been made, the task of finding cost-effective solutions will still continue. The tendency of solid fertilizers to cake and form large stiff masses is one the principal problems associated with their manufacture, handling and application.The cause of caking of most fertilizers is the growth of crystal bonds between fertilizer particles. These crystals develop during storage due to continuing internal chemical reaction or thermal effects, which in the deposition of crystals, from minute amount of salt solutions present in fertilizer. Inter-growth of such crystals between granules or between particles of non-granular product result in caking.The scope of this paper covers the mechanisms of caking, factors affecting caking, and methods of their prevention. In addition to, the various potential anti-caking additives are surveyed, and their mode of action reconsidered in the light of the proposed mechanisms of caking.

The efficiency of a reactor equipped with floating ultra violate lamp used for sterilizing water distribution system samples in the residential complex of Fariman Sugar Factory at the point of consumption was studied. And the capability of disinfecting methods for dark samples less than 1 Nephlometre under the 14.5 seconds duration with the passage of 150 mm. Was identified. Using Potassium Phosphate by Actinometrical method the rate of emission at the start and at the end of the cycle was measured and accordingly the control of the rate of emission from the ultra violate lamp in the absence of Radio meter become possible. Another achievement of the present research is the possibilities of disinfection by ultra violate lamp using darkness measurement at the entrance of the water to the ultra violate Reactor.

In this paper which is a part of results of two research projects about the conversion of a direct injection diesel engine in order of investigation of its performance with DME fuel instead of gas oil, and optimize production of DME, we will familiar with DME as diesel fuel, and some of its advantages such as clean fuel with lower pollution and appropriate performance and excellent cetane number are introduced. Also, some of the achieved results from using DME in a converted engine are reported. It is shown that the application of DME instead of gas oil doesn’t have any important effect on torque and power loss. In addition, referring to non-existing of smoke limit phenomena, the nominal speed and acceleration of engine can be increased. Also, two industrial methods for production of DME have been discussed, namely, direct method which uses synthesis gas as feed, and indirect method which uses methanol as starting raw material. The catalysts of each method have been investigated and indirect method has been selected as an appropriate method for DME production. Finally, a bench scale set up is introduced. This set up is designed and constructed for the DME process studies based on the selected production method.

Membrane bioreactors (MBRs) have been widely used as advanced wastewater treatment process in recent years. However, MBR system has a membrane fouling problem, which makes the system less competitive. In general, membrane fouling occurs more seriously on hydrophobic membranes than hydrophilic ones because of hydrophobic interaction between solutes, microbial cells, and membrane materials. Membrane fouling can also be attributed to the adsorption of organic species, the precipitation of less soluble inorganic species, and the adhesion of microbial cells at the membrane surface. One way for modification of membrane surface is CO2-plasma treatment. It seems that the pore size and porosity of the membranes after plasma treatment increased at first then decreased with the increase of plasma treatment time. The other way is immobilization of TiO2 nanoparticles on/in membranes. TiO2 deposited membrane shows greater fouling mitigation effect compared to that of TiO2 entrapped membrane. Regardless of polymeric material, membrane fouling is mitigated by TiO2 immobilization. It can be concluded that TiO2 immobilized membranes are simple and powerful alternative for fouling mitigation in MBR application.

Consumption of natural gas has been increasing rapidly making it one of the most important energy resources in the world. During the last decade the consumption of natural gas increased by almost 25%.By 2020 natural gas is predicted to increase its world energy share to as much as 50% from the present of 22%.The scale of its reserves and its environmental advantages favor its use,(The lower carbon emissions compared to oil and coal along with other reduced emissions of nitrogen oxides and particulates) for fast growing activities such as the precision industries and the generation of electricity. During the twenty last year natural gas reserves have increased about twice. However the technical costs of the production, processing and, above all, the transport of natural gas nonetheless remain high and represent a handicap. This difficulty is made worse because the proportion of natural gas reserves located offshore and in difficult zones (Arctic,Siberia) is tending to grow. In this situation the technical advance that help to reduce these costs should play a major role in the future in the growth of the international natural gas trade. Therefore ways of transporting the gas from offshore reserves and overseas sources have generated considerable and renewed interest.Existing means of transporting natural gas consist primarily of pipelines and LNG (Liquefied of natural gas). Pipelines account for 75%, with LNG making for the rest.Pipelines are the obvious means for the onshore transport of natural gas. But for offshore transport (As the water depth and distance between sources and users increase)pipelines become economically unattractive. LNG provides then an appropriate way of delivering natural gas near the facilities to support a LNG project and get acceptable returns capital investment. The Adsorbed Natural Gas (ANG) and Natural Gas Hydrate (NGH) technologies can be used readily for the transporting of gas from smaller and marginal fields. These are simple and can be easily brought in to commercial application.Industry and academic have been pursuring the chemical conversion of natural gas to higher valued products. Potential process routes include the manufactory of olefins and chemical intermediates, methanol, ethylene, gasoline and distillate fuels. Today the indirect conversion via synthesis gas is the preferred route. Although it is energy efficient and involves large investments and is expensive. The direct conversion of natural gas into products is still far from being feasible, but it represent a potential for a break-through and involves lower investments and is cheaper.

The purpose of this paper is to find Energy Consumption Index of the best petrochemical units in the world and doing compare between these indexes and internal indexes in Iran. In this regard deliberation of modern technologies about Amonia and Poly Ethylen (PE) for benchmarking and also index derivation for internal performances are our exemplary. In this study Arak petrochemical plant, Shiraz petrochemical plant and Bandar Emam petrochemical plant are selected. After comparing between global optimum energy index and internal energy index suggestions will submit for improvement.