توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Activity of LaMO3 (M=Mn, Fe, CO, and Ni) perovskite catalysts for Oxidation of exhaust gaspollutants of natural gas vehicles
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۵
Different LaMO3 (M= Mn, Fe, Co and Ni) perovskite–type catalysts were prepared via solution combustion method, calcined at 700oC for 5 h and were characterized by X–ray diffraction method (XRD), BET specific surface area and H2 temperature programmed reduction (TPR). The catalysts activity for the abatement of pollutants (i.e. CO and CH4) emitted from natural–gas (NG) fuelled vehicles were investigated using a synthetic exhaust conditions. A gas mixture of 2 vol% CO and 2000 ppm CH4 in Ar together with proper flow of air (SN=1.1) was used as the synthetic exhaust gas of NG engines. LaCoO3 presents the best performance for CO oxidation among other catalysts examined. The 90% conversion temperature of CO is 235oC over LaCoO3 that is 113oC lower than LaMnO3 (i.e. the least active catalyst for CO oxidation). On the other hand, LaFeO3 is found to be the most active catalyst for CH4 oxidation. The half–conversion temperature of CH4 is 553oC over LaFeO3 which is 82oC lower than LaNiO3– that shows the least activity in CH4 oxidation. TPR results reveal that perovskites which reduce at moderate temperatures show higher activity for CO oxidation, while catalysts that are more stable at higher temperatures, show better performance for CH4 oxidation.<\div>

۲An investigation of influence of copper on the redox properties and catalytic performance of LaMnO3+λ perovskite– type catalyst
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۵
Modified perovskite–type oxides were synthesized through gel combustion method. The synthesized perovskite materials had the nominal compositions of LaMnO3 and LaMnCu0.1O3. The catalytic activity of the perovskite samples (for low–temperature CO and C3H8 oxidation) was measured using a quartz reactor with an inlet gas mixture containing CO, propane, O2 as synthetic automotive exhaust gas and Ar as an inert gas. The prepared perovskite samples were characterized by nitrogen adsorption (BET), XRD and TPR analyses. TPR and XRD results may indicate that copper was in the form of solid solution in perovskite structure and the excess manganese oxide in LaMnCu0.1O3+δ is in the form of amorphous small particles. The perovskite catalysts showed high activity for the catalytic CO and propane oxidation reaction. LaMnCu0.1O3 achieved the same CO and propane conversion at lower temperatures than LaMnO3. The light off temperature for CO and propane on LaMnCu0.1O3 were lower by 70 and 20oC, as compared to that of LaMnO3 perovskite. Hence, for the environmental application of the automotive emission control, these catalysts can completely eliminate the poisonous CO and unburned hydrocarbons.<\div>

۳The Possibility of Using Thioglycolic acid instead of sodium sulfide in the Molybdenum Enrichment Plant of Sarcheshmeh Copper Complex
نویسنده(ها): ، ، ،
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۵
In this research the use of Thioglycolic Acid (TGA) as a copper and iron sulfides depressant instead of sodium sulfide in the Molybdenum Enrichment Plant of Sarcheshmeh Copper Complex has been studied in laboratory scale. After determining and optimizing the main effective factors on the molybdenum recovery and copper depression, the flotation tests of rougher stage and seven cleaner stages were done subsequently and the variation of molybdenum recovery and copper depression resulted from two mentioned depressants were compared. It found that the depressing effect of TGA was better than sodium sulfide and resulted in high recovery of molybdenum. The use grades of impurities in the final concentrate found under standard ranges and were desirable. This reagent was found suitable environmentally, metallurgically, operationally and economically.<\div>

۴Evaluation of Mn–Cu and La–Mn–Cu mixed oxide catalysts for efficient CO oxidation
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۴
Mixed oxides of manganese–copper and manganese–copper–lanthanum with the mole ratio of Cu\ Mn=0.2 and Mn\La=1 have been prepared and evaluated in CO combustion. The gel combustion method used for the synthesis of MnCu0.2Ox and LaMnCu0.2O3+d mixed oxides is adequate to obtain catalysts with excellent catalytic performance in combustion reactions. Catalysts were characterized by means of BET, XRD, H2–TPR. The catalytic activity of the perovskite samples (for low–temperature oxidation) was measured using a quartz reactor with an inlet gas containingCO as pollutant gas, O2 and Ar as an inert gas. The mixed oxide catalysts showed high activity for the catalytic CO oxidation reaction. LaMnCu0.2O3 achieved the same CO conversion at lower temperatures than to Cu0.2MnOx.<\div>

۵Integration of oxidative coupling of methane (OCM) and dehydrogenation of ethane for enhancement of C2H4 yield over Mn–Na2WO4\SiO2 catalyst
نویسنده(ها): ، ،
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۶
Oxidative coupling of methane is considered to be one of the direct routes in natural gas conversion into more added value hydrocarbons. In this work, an integrated process, comprising OCM and dehydrogenation of ethane, for improving the C2H4 yield is introduced. The reactions are performed in a vertical quartz reactor having two reaction parts which operates at ambient pressure. The best results are obtained when OCM reactions take place on Mn– Na2WO4\SiO2 catalyst located in the upper reaction part followed by noncatalytical reactions performed in the second reaction part at CH4\O2=7\1 and 800°C. The operation led to a maximum C2H4 selectivity and ethylene yield of 37.9% and 16.0% respectively.<\div>

۶Comparative study on catalytic and non catalytic dehydrogenation of ethane to ethylene over MN\Na2WO4\SiO2 by oxygen and CO2 as an oxidant
نویسنده(ها): ، ،
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۵
investigation on the catalytic and non catalytic oxidative dehydrogenation of ethane (ODE) to ethylene by carbon dioxide or oxygen as an oxidant have been carried out at 800oC. The reactions are performed in a vertical quartz reactor which operates at ambient pressure. For the catalytic experiments MN\Na2WO4\SiO2 was used as a catalyst which is fabricated by the dry impregnation method and calcined in air at 850oC for 8 h. The non–catalytic ODE reaction by CO2 and O2 led to ethylene selectivity of 97% and 88% respectively.<\div>

۷Effect of excess palladium on the activity of perovskite catalysts for Oxidation of exhaust gas pollutants emitted from natural gas fueled vehicles (NGFVs)
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۵
LaMnO3 and LaMnPd0.05O3 (contains 2.15 wt% Pd) perovskite–type catalysts were prepared via solution combustion method, calcined at 700oC for 5 h and were characterized by X–ray diffraction method (XRD), BET specific surface area and H2 temperature programmed reduction (TPR). The catalysts activity for the abatement of pollutants (i.e. CO and CH4) emitted from natural–gas (NG) fuelled vehicles were investigated using a synthetic exhaust conditions. A gas mixture of 2 vol% CO and 2000 ppm CH4 in Ar together with proper flow of air (SN=1.1) was used as the synthetic exhaust gas of NG engines. Activity results show that T90% conversion for CO and CH4 oxidation reduces 130oC and 35oC respectively when small amount of excess Pd inserts into perovskite structure. The Pd content has a great influence on the activity below 500oC; however this effect would be moderated at temperatures above 500oC probably as a result of increasing temperature which favors the reduction of PdO to metallic Pd that appears to be less active than PdO. TPR results reveal that reduction temperature of Mn+4 to Mn+3 ions is reduced about 200oC for Pd containing perovskite; however, no discernable effect on the reduction temperature of Mn+3 to Mn+2 ions is observed.<\div>

۸Nanoclay for the Removal of Heavy Metals (Lead and Zinc) from Aqueous Solutions
نویسنده(ها): ، ،
اطلاعات انتشار: اولین کنفرانس بین المللی تصفیه فاضلاب و بازیافت آب، فناوری ها و یافته های نو، سال
تعداد صفحات: ۱۰
Water lackage, irregular and wrong usage of water resources, and their pollution in Arid and semi–arid zones is a serious threat for sustainable development and environmental protection. sustainable development and humanity life continuance is relevant to environmental and natural sources preservation. We have assessed the capacity of montmorillonite nanoclay to uptake heavy metals from (such as zinc and lead) aqueous solutions, industrial wastewater effluent and landfill bottoms. The data of adsorption in aqueous solutions were fitted to the linear model: q (g\kg) = A*C(mg\L)+B where A and B are found for each material experimentally. Batch experiments were performed to evaluate the effects of contact time and initial concentration on the zinc and lead sorption. The nanoclay effectively removed heavy metals from a wide range of concentrations at high solution\nanoclay ratios. The results were also analysed if they fit to Langmuir or Freundlich sorption Equations, too. This finding together with the low cost and environmentally friendly nature of nanoclay makes this material a superior candidate for the remediation of landfill leachates and treatment of water, metal–rich effluent and sewage. An added advantage is that nanoclay does not disperse in water, and hence can be recovered after use.<\div>

۹New sorbent for desulfurization of liquid fuels
اطلاعات انتشار: چهاردهمین کنگره ملی مهندسی شیمی ایران، سال
تعداد صفحات: ۵
In this research, nano CuO was used as new sorbent and its ability to adsorb sulfur compound was investigated. Different parameters such as, adsorption temperature, contact time, dose of nano particle, initial sulfur concentration was investigated. The results indicate that in the first ten minutes the high presentage about 60% of total sulfur was removed. Kinetic study for adsorbent has shown that the reaction path was pseudo – second order. Equilibrium data were best described by the freundlich isotherm model<\div>

۱۰Investigation of the effect of friction on the ballistic performance offabric targets
نویسنده(ها): ، ، ،
اطلاعات انتشار: کنفرانس دو سالانه بین المللی مکانیک جامدات تجربی، سال
تعداد صفحات: ۸
In this study, the effects of friction on ballistic performance of fabrics used in armors have been investigated. Residual velocity was obtained as a criterion of ballistic performance of fabric. For this purpose, ballistic tests were performed on the Kevlar fabric and double plies of fabric were shot with hemispherical projectiles. Also a finite element model was developed using LS–DYNA software. The result of the simulation shows an acceptable agreement between the experimental and numerical analysis. Friction was introduced between Kevlar yarns and also between the projectile and the fabric. Results show that friction has an effect on decreasing projectile velocity via delaying fabric failure and therefore improve fabric ballistic performance. The simulation result may be a proof that the increased ballistic performance for shear thickening fluid impregnated Kevlar fabric is at least due to the increased friction.<\div>
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