توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Calculation of solubility of CO2 and H2S acid gases in aqueous MDEA solution applicable in gas sweetening processes
نویسنده(ها): ،
اطلاعات انتشار: سومین کنفرانس تخصصی ترمودینامیک، سال
تعداد صفحات: ۸
Three molecular activity coefficient models with the aid of ion pair concept are used to model the solubility of CO2 and H2S acid gases in the aqueous methyldiethanolamine(MDEA) solution. The gas phase nonideality is considered using the SRK equation of state. For the liquid phase, an activity local composition model is applied that the Pitzer–Debye–Hückel theory is used as a shortrange term. The N–Wilson–NRF, NRTL–NRF and UNIQUAC–NRF activity coefficient models are used as the short–range term. The interaction parameters of the binary MDEA–H2O, CO2–H2O and H2S–H2O systems are obtained using the corrosponding solubility data of literature. Using the optimazed binary parameters, the other binary interaction parameters for the two ternary systems of MDEA–CO2–H2O and MDEA–H2S–H2O are caculated. A good agreement between the experimental data and the correlated results are obtained .<\div>

۲Experimental Measurment of Methane Hydrate Equilibria in the Presence of Aqueous Imidazolium–based Ionic Liquid Solutions
نویسنده(ها): ، ، ،
اطلاعات انتشار: چهاردهمین کنگره ملی مهندسی شیمی ایران، سال
تعداد صفحات: ۴
Methane hydrate dissociation conditions in the presence of imidazolium based aqueous ionic liquid solutions including 1–buthyl–3–methylimidazolium methyl sulfate ([BMIM][MeSO4]) , 1–ethyl–3–methylimidazolium hydrogen sulfate ([EMIM][HSO4]) and 1–1–ethyl–3– methylimidazolium ethyl sulfate [EMIM][EtSO4] are investigated. The reliability of the experimental procedure in this work is demonstrated by comparing methane hydrate dissociation data in pure water with literature. The comparison between methane hydrate dissociation conditions in the presence\absence of ionic liquid solutions is shown. It is found that amongalkylsulfate–containing ionic liquids, the thermodynamic inhibition effects of two ionic liquids such as [EMIM][HSO4] and [BMIM][MeSO4] are better than that of [EMIM][EtSO4<\div>

۳A new kinetic modeling of the Fischer–Tropsch synthesis in a slurry bubble column reactor using Langmuir–Freundlich isotherm
نویسنده(ها): ، ،
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۸
A comprehensive kinetic model for the Fischer–Tropsch synthesis in a slurry phase bubble column reactor is developed. The several mechanisms for kinetic modeling of Fischer–Tropsch synthesis have been developed in which the Langmuir isotherm is the basis of kinetic modeling of the catalytic reactions. In present study, we employed the Langmuir–Freundlich isotherm for Fischer– Tropsch synthesis that is a modification of the commonly used Langmuir isotherm. Since the Langmuir–Freundlich isotherm can predict the adsorption of gases at solid absorbent more accurate than Langmuir isotherm, thus, the new Langmuir–Freundlich–Hinshelwood (LFH) kinetic model is developed for FT synthesis so that this model is applied to correlation of the CO conversion in a slurry bubble column reactor. Using LFH model, the results of CO conversion in a slurry bubble column reactor show a very good agreement with the experiment over the wide range of the reactor conditions of 523–563K, 0.95–2.55 MPa and H2\CO ratio: 0.65–1.51. Finally, results of the new kinetic LFH model shows that the Average Absolute Deviation percentage of 5.42% for CO conversion while this value is about 10.89% using the original equation based on Langmuir isotherm.<\div>

۴Application of Electrolyte Cubic Square–Well Equation of State for Prediction of the Gas Hydrate Formation in the Presence of Electrolyte Solutions
نویسنده(ها): ، ، ،
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۸
Electrolyte Cubic Square–Well Equation of State, eCSW EOS, [Haghtalab, A.; Mazloumi, S.H.;Fluid Phase Equilib. 2009, 285, 96–104] is based upon cubic–square–well equation of state. This equation of state is composed of the attractive term that is based on the square–well potential, thevan der Waals repulsive part and the mean spherical approximation theory (MSA) for electrostatic contribution. In this work, eCSW EOS is coupled with the van der Waals–Platteuw model andapplied to compute the conditions of gas hydrate formation. The H–L–V equilibrium calculation isperformed to optimize the Langmuir constants against temperature for N2, CH4, C2H6, C3H8, i– C4H10, n–C4H10 and CO2 hydrates using the experimental data in literature. Also, using eCSW EOS the interaction parameters of CO2–water and electrolyte–water are obtained. The equilibrium hydrate formation pressures of single gas hydrates are predicted and the results compared with the calculated values using SRK and PR EOSs. Also, predicting equilibrium hydrateformation pressures of various hydrate formers in the presence of electrolytes such as NaCl, KCland CaCl2 are performed. The results of prediction at the different cases are in good agreement with the experiments<\div>

۵Study of the Effective Variables on Morphology and Deposition of CaC03 on the Metal Surface
نویسنده(ها): ، ،
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۹
Using an electrochemical technique, deposition and crystal growth of calcium carbonate is investigated on a rotating disk electrode by oxygen reduction under diffusion conditions. The effect of some parameters such as pressure, surfactant, cosalt on morphology and deposition of CaC03 at surface of the stainless steel is investigated using a rotating disk electrode and the scanning electronic microscopic. The results of temperature effect present that the surface deposition reduces with increasing of temperature and decreases with reduction of pH. The pressure has a significant influence on the morphology and the structure of calcium carbonate deposition on the metal surface so that with producing a flow condition at high pressure, nucleation and deposition of calcium carbonate on the metal surface favoured the nanoscale size of CaC03 and leads to reduction in the coverage of surface. In the presence of surfactant, it can be shown that deposition of the calcium carbonate decreases the surface coverage so that after the point of the CMC of CTAB surfactant one can observe a reduction of deposition of the calcium carbonate at the surface. Finally, influence of the monovalent cosalt such as NaCl and KCl presents no certain trend in the deposition, but morphology of the surface is changed.<\div>

۶Modeling of the Fischer–Tropsch Synthesis in a fixed bed reactor using a new kinetic model based on the Langmuir–Freundlich isotherm
نویسنده(ها): ،
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۷
A Gas to Liquid (GTL) process, which consists of the three stages, converts natural gas to wax and useful hydrocarbons such as benzene and gas oil. In the second stage of a GTL process, the syngas via cobalt or iron catalyst is converted to wax that this step is referred to the Fischer–TropschSynthesis (FTS). Using a slurry or fixed bed reactor, in FTS a durable catalyst should be designed to maximize the CO conversion and produce a suitable distribution of hydrocarbons. In this work, a detailed kinetic model for the FTS over a cobalt catalyst is developed. The commonly usedkinetic model of FTS such as Langmuir–Hinshelwood was developed on the basis of Langmuir isotherm. Since the Langmuir–Freundlich isotherm can predict the adsorption of gases on solid adsorbent more accurate than Langmuir isotherm, we employed this isotherm to develop the newLangmuir–Freundlich–Hinshelwood (LFH) kinetic model. As a result, using the new kinetic model the percent of Average Absolute Deviation is reduced for correlation of the experimental COconversion data in a fixed bed reactor. In order to evaluate our new kinetic model, we use the experimental data of Y. W. Li et al. that was relevant to the industrial operational conditions [temperature, 540–600 K; pressure, 1.0–3.0 MPa; H2\CO feed ratio, 1.0–3.0]. The results show a very good agreement with the available experimental data. To have a good accession of the new model, we compare the present results with those are obtained using common Langmuir– Hinshelwood isotherm as well and evaluated the strength of the two models in prediction of theCO conversion for the FTS at a fixed bed reactor. The results of the new kinetic model show theaverage absolute deviation percentage (AAD %) of 5.59% for the CO conversion while this value is about 18.1% using the original equation based on Langmuir isotherm.<\div>
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