توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Effects of Space Velocity on Direct Synthesis of Dimethyl from Synthesis gas
نویسنده(ها): ، ، ،
اطلاعات انتشار: یازدهمین کنگره ملی مهندسی شیمی ایران، سال
تعداد صفحات: ۸
The space velocity had profound effects on dimethyl ether synthesis from syngas over bi–functional catalyst at 513 K and 3.5 MPa. The bi–functional catalyst was prepared by physical mixing of CuO\ZnO\Al2O3 (methanol synthesis catalyst) and H–ZSM–5 (methanol dehydration catalyst) and then characterized by BET, XRD, XRF and TPR analysis. The results indicated that yield of DME as well as the conversion of CO increased continuously with decreasing the space velocity and\ or increasing the residence time of reactants. The main by–products of DME synthesis were water, CO2 and methane. Below a certain space velocity (1100 mln\gr.cat–hr), DME yields and productivities showed a maximum with H2O concentration about 2–10%. Furthermore, it was found that the exit concentration of CO2 has a similar trend as DME yield with decreasing the space velocity. The space velocity that gave the maximal rate of DME production also depended on the H2\CO ratio of feed. In DME synthesis reaction, it was observed that the feed with H2\CO ratio equal to 1.5, have higher activity. For a feed consist of H2 and CO, an optimal space velocity exists for obtaining the kinetic and thermodynamic data for direct synthesis of dimethyl ether.<\div>

۲Thermodynamic Equilibrium Calculations of LPDME Process from Synthesis gas
نویسنده(ها): ، ،
اطلاعات انتشار: پنجمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۱۳
Thermodynamic analysis of single–step synthesis of dimethyl ether (DME) from syngas over a bi– functional catalyst in a slurry bed reactor have been investigated as a function of temperature (200–240 ◦C), Pressure (20–50 bar) and composition of feed ratio (H2\CO: 1–2). The bi–functional catalyst was prepared by physical mixing of CuO\ZnO\Al2O3 as a methanol synthesis catalyst and H–ZSM–5 as a methanol dehydration catalyst. The three reactions including methanol synthesis from CO and H2, methanol dehydration to dimethyl ether (DME) and water–gas shift reaction were chosen as the independent reactions. Thermodynamic equilibrium constants of these reactions and equilibrium composition of all components were determined from experimental and theoretical calculations. Moreover, the effect of reaction temperature, pressure and H2\CO ratio in feed at equilibrium conditions were predicted by thermodynamic model.<\div>

۳Investigating methods and effective parameters in the adsorption of mercury from aqueous solutions
نویسنده(ها): ، ،
اطلاعات انتشار: پنجمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۹
A serious environmental threat from heavy metal ion pollution, especially mercury, has generated a great deal of attention in recent years. In this paper, we have evaluated the efforts which have been done for controlling the mercury emissions from aqueous solutions. According to the Indian Standard Institution, the tolerance limit for Hg (II) for discharge into inland surface water is 10µg\l and for drinking water is 1µg\l. Mercury (Hg) is one of the heavy metals of concern and has been found in the waste waters coming from manufacturing industry, oil refinery, materials rocessing and natural sources. Among several types of technology for removing of Hg in water (chemical precipitation, reverse osmosis, ion–exchange, etc.), adsorption is one of most frequently used. It is a complex process involving physical, chemical, and electrical interactions at sorbent surfaces.<\div>

۴Intrinsic Kinetics Study of LPDME Process from Syngas over Bi–functional Catalyst
نویسنده(ها): ، ،
اطلاعات انتشار: پنجمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۱۲
The intrinsic kinetics of the three phase dimethyl ether (DME) synthesis from syngas over a bi– functional catalyst has been investigated in a agitated slurry reactor at 20–50 bar, 200–240 o C and H2\CO feed ratio from 1 to 2 .The bi–functional catalyst was prepared by physical mixing of CuO\ZnO\Al2O3 as methanol synthesis catalyst and H–ZSM–5 as methanol dehydration catalyst. The three reaction including methanol synthesis from CO and H2, methanol dehydration and water–gas shift reaction were chosen as the independent reaction. A kinetic model for the combined methanol + DME synthesis based on a methanol synthesis model proposed by Graaf (1988) and a methanol dehydration model by Bercic and Levec (1992) has been fit our experimental data. Coefficients in the equations follow the Arrhenius and the Van’t Hoff relation. The calculated apparent activation energy of methanol synthesis reaction and methanol dehydration reaction are 115kJ\mol and 82kJ\mol, respectively.<\div>
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