توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱The Promoter Effects and Pressure in Fischer–Tropsch iron–manganes catalyst
نویسنده(ها): ، ،
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۹
The effects of K, Ce, Zn, Cs or Rb promoters on the structure and catalytic behavior of precipitated 50%Fe\50%Mn Fischer–Tropsch synthesis (FTS) catalysts were investigated in a fixed–bed reactor. The catalysts are characterized using X–ray diffraction (XRD). It was found that the 50%Fe\50%Mn catalyst that was promoted with K is an optimal catalyst for the conversion of synthesis gas to hydrocarbons especially light olefins. The effect on the 1–alkene selectivity is without doubt due to increased adsorption strength of carbonmonoxide causing an enhanceddisplacement of 1–alkenes while the propensity towards hydrogenation is hardly reduced.The catalysts were assessed in terms of their FTS activity and product selectivity using Anderson– Schulz–Flory (ASF) models. The promoter effect on Fischer–Tropsch iron catalysts caused an increased growth probability of hydrocarbon chains from 0.72 to 0.81 for K to Rb promoter and the olefin\paraffin ratios were increase from Rb to K–promoted catalyst, consequently. Also The effect of pressure on Fe\Mn\K was studied and experiments are presented which show that with pressure increasing, olefin\paraffin ratio decrease from 2.40 to 1.22 while the (α) increase from 0.80 to 0.86.<\div>

۲Kinetic modeling of CO hydrogenation over a bimetallic Co\Ni catalyst in fixed bed reactor
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۱۲
An active Co–Ni\Al2O3 catalyst was prepared by impregnation method to synthesize light olefins in Fischer–Tropsch Synthesis. The kinetic experiment study was performed in a differential micro– fixed–bed–reactor by varying reaction temperature (230–270 °C), pressure (2–12 bar), gas hourly space velocity (2000–7200 h–1) and H2\CO feed molar ratio (1–3). Based on Langmuir– Hinshelwood–Hougen–Watson (LHHW) approach, seven different two–parameter kinetic models were considered. The kinetic data of this study were fitted fairly well by a simple form that assumed the following kinetically relevant steps: CO dissociated via interaction with adsorbed H; the first hydrogenation of surface carbon step was reversible and fast, while the second was slow and rate determining. The kinetic parameters were determined using Levenberg–Marquardt (LM) method and the apparent activation energy and heat of adsorption were 78.70 kJ\mol and –14.16 kJ\mol, respectively.<\div>

۳Development of a Macro Kinetic Expression for the Iron–based Low–Temperature Fischer–Tropsch Synthesis
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۱۰
In this experimental study, a kinetic model has been developed for Fischer–Tropsch synthesis reactions by using Fe\Ni\Al2O3 as the catalyst (40% Fe\60% Ce\40wt%Al2O3) in a fixed–bed micro reactor assuming no internal or external diffusion. Operating conditions of the reactor are as follows: reactor total pressure 1–12 atm ; Temperature 220–260 ºC; H2\CO feed ratio 1–2 and space velocity 4200 hr–1. Considering the mechanism of the process and Langmuir–Hinshelwood–Hogan–Watson (LHHW) approach, four different mechanisms, namely carbide, enol, combined carbide– enol, and parallel carbide–enol were defined for CO consumption rate equations. The kinetic data of this study are fitted fairly well by a simple form − r = AP 0.5 P\(1 + k P+ kP ) 2CO H 2 COCO COH 2OH 2Osimilar to that suggested by Botes. The obtained rate expressions for the COhydrogenation reactions from nonlinear regression analysis and Levenberg–Marquardt method demonstrate that the formation of monomer species (HCOs) due to CO hydrogenation reaction has controlled the FTS reaction rate. The activation energy and adsorption enthalpy toward CO and H2O were calculated as 78.58 kJ \mol and –30.56 kJ \mol and 30.94 respectively.<\div>

۴Route to No–flaring and No CO2 emission in the Gas Refinery
نویسنده(ها): ، ،
اطلاعات انتشار: نخستین کنفرانس بین المللی نفت، گاز و پتروشیمی با رویکرد توسعه پایدار (ارتباط دانشگاه با صنعت)، سال
تعداد صفحات: ۱۱
Each The mitigation and utilization of greenhouse gases, such as carbon dioxide and methane, are among the most important challenges in the area of energy research. In the gas refinery, tail gas in sulfur recovery unit is a main source of CO2 emission and the natural gas to flare is also a source of methane and CO2. In this paper, Dry Reforming– Fischer–Tropsch Synthesis–Catalytic Dehydrogenation (DRM–FTS–CDH) process isproposed to recover flare gas and tail gas in the gas refinery and calculation and simulation was done. Dry reforming of CH4 (DRM), which uses both CO2 and CH4 as reactants, is a potential method to utilize the greenhouse gases in the atmosphere. DRM offers several advantages: a) mitigation of CO2 and natural gas; b) transformation of natural gas and CO2 into valuable syngas; c) effective utilization of low–grade natural gas resources consisting of natural gas and CO2. Hydrogen in the product could be applied as a fuel in fuel cells and the syngas can be converted efficiently to ultraclean fuels, such as gasoline, gasoil with no sulfur and less aromatic byproducts, by Fischer–Tropsch synthesis (FTS). But with respect to nature of DRM process which results in a H2\CO ratio of less than unity while FTS of liquid fuels requires syngas with H2\CO≥2.0. By producing the required H2 by catalytic dehydrogenation (CDH) of the gaseous (C1–C4) products of FTS, instead of WGS reaction, it could be retrieved shortage of H2\CO ratio. In this research basic supports such as alumina, Fe–Mn–K catalyst and carbon nanotubes selected for DRM–FTSCDH, respectively. This new process is a suitable alternative to conventional gas flaring which prevents harmful environmental effects through emission of significant amounts of carbon dioxide in the atmosphere.<\div>
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