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Berthold B. Breman - One of the best experts on this subject based on the ideXlab platform.
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development and testing of a new macro Kinetic Expression for the iron based low temperature fischer tropsch reaction
Industrial & Engineering Chemistry Research, 2006Co-Authors: Gideon F Botes, Berthold B. BremanAbstract:Based on the common belief that water inhibits the intrinsic Fischer-Tropsch (FT) reaction rate in the ironFT synthesis, water is included in almost all iron-FT Kinetic Expressions. A new rate Expression is now proposed where vacant sites, CO, and water are all included in the denominator. This model was evaluated with data from various historical experimental studies. In all cases it was found that the effect of water is not statistically significant and should therefore be omitted from the model. The new model describes the historical data more accurately than some other popular rate equations. To validate these conclusions, new experimental data were measured in a well-mixed slurry reactor in the absence of mass transfer limitations. The experimental methodology employed ensured that the iron-FT catalyst did not suffer measurable deactivation. It was confirmed that there is no basis for including water in the denominator of the new rate equation and that it is more accurate than the rival models considered.
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Development and Testing of a New Macro Kinetic Expression for the Iron-Based Low-Temperature Fischer−Tropsch Reaction
Industrial & Engineering Chemistry Research, 2006Co-Authors: F. Gideon Botes, Berthold B. BremanAbstract:Based on the common belief that water inhibits the intrinsic Fischer-Tropsch (FT) reaction rate in the ironFT synthesis, water is included in almost all iron-FT Kinetic Expressions. A new rate Expression is now proposed where vacant sites, CO, and water are all included in the denominator. This model was evaluated with data from various historical experimental studies. In all cases it was found that the effect of water is not statistically significant and should therefore be omitted from the model. The new model describes the historical data more accurately than some other popular rate equations. To validate these conclusions, new experimental data were measured in a well-mixed slurry reactor in the absence of mass transfer limitations. The experimental methodology employed ensured that the iron-FT catalyst did not suffer measurable deactivation. It was confirmed that there is no basis for including water in the denominator of the new rate equation and that it is more accurate than the rival models considered.
Anuradha Varshney - One of the best experts on this subject based on the ideXlab platform.
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p nitrobenzyltriphenyl phosphonium ylide initiated radical terpolymerization of styrene methyl methacrylate and acrylonitrile synthesis characterization and properties
Polymer International, 2007Co-Authors: Kiran Prajapati, Anuradha VarshneyAbstract:Solution terpolymerization of styrene (St), methyl methacrylate (MMA) and acrylonitrile (AN) was carried out in dioxane at 65 ± 0.1 °C for 120 min using p-nitrobenzyltriphenyl phosphonium ylide as radical initiator. The Kinetic Expression is as follows (Rp is the rate of polymerization): Rp∝ [ylide]0.45[St]0.8[MMA]1.2[AN]1.2. The overall activation energy is 42 kJ mol−1 L−1. The composition of terpolymer, calculated from 1H NMR and elemental analysis, was used to evaluate reactivity ratio, as r1 (MMA + AN) = 0.06 and r2 (St) = 0.005, employing the Kelen–Tudos method. It confirmed the alternating nature of the terpolymer. The terpolymer was characterized using 13C NMR, gel permeation chromatography and thermogravimetric differential thermal analysis. Electron spin resonance spectroscopy confirmed the presence of the phenyl radical responsible for initiation. Copyright © 2006 Society of Chemical Industry
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p‐Nitrobenzyltriphenyl phosphonium ylide‐initiated radical terpolymerization of styrene, methyl methacrylate and acrylonitrile: synthesis, characterization and properties
Polymer International, 2006Co-Authors: Kiran Prajapati, Anuradha VarshneyAbstract:Solution terpolymerization of styrene (St), methyl methacrylate (MMA) and acrylonitrile (AN) was carried out in dioxane at 65 ± 0.1 °C for 120 min using p-nitrobenzyltriphenyl phosphonium ylide as radical initiator. The Kinetic Expression is as follows (Rp is the rate of polymerization): Rp∝ [ylide]0.45[St]0.8[MMA]1.2[AN]1.2. The overall activation energy is 42 kJ mol−1 L−1. The composition of terpolymer, calculated from 1H NMR and elemental analysis, was used to evaluate reactivity ratio, as r1 (MMA + AN) = 0.06 and r2 (St) = 0.005, employing the Kelen–Tudos method. It confirmed the alternating nature of the terpolymer. The terpolymer was characterized using 13C NMR, gel permeation chromatography and thermogravimetric differential thermal analysis. Electron spin resonance spectroscopy confirmed the presence of the phenyl radical responsible for initiation. Copyright © 2006 Society of Chemical Industry
Yong Ki Park - One of the best experts on this subject based on the ideXlab platform.
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Kinetic Expression for the Carbonation Reaction of K2CO3/ZrO2 Sorbent for CO2 Capture
Industrial & Engineering Chemistry Research, 2013Co-Authors: Deuk Ki Lee, Da Young Min, Hwimin Seo, Na Young Kang, Won Choon Choi, Yong Ki ParkAbstract:For the Kinetic study of K2CO3/ZrO2 sorbent in the carbonation reaction to capture CO2 from the flue gas, reaction experiments were carried out at temperatures between 328 and 343 K for CO2 gas compositions not exceeding 18% at 1 bar, and a phenomenological Kinetic model was proposed to fit the carbonation conversion data obtained. Time-dependent carbonation conversions of the sorbent appeared as sigmoid curves. Sigmoid characteristics of the conversion curve were more pronounced for the sorption reaction at lower temperature and lower gas phase concentration of CO2. Such conversion behavior of fresh-dried K2CO3/ZrO2 sorbent could be closely described with the reaction rate equation in the form: r = kf(X)yCO2n . The reaction rate constant k as a temperature dependent term could be represented by Arrhenius’ equation with the negative apparent activation energy of −17.43 kJ/mol and the pre-exponential factor of 3.83 × 10–3 1/min. The term f(X) was a function introduced to reflect the carbonation rate change...
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Kinetic Expression for the carbonation reaction of k2co3 zro2 sorbent for co2 capture
Industrial & Engineering Chemistry Research, 2013Co-Authors: Deuk Ki Lee, Hwimin Seo, Na Young Kang, Won Choon Choi, Da Young Min, Yong Ki ParkAbstract:For the Kinetic study of K2CO3/ZrO2 sorbent in the carbonation reaction to capture CO2 from the flue gas, reaction experiments were carried out at temperatures between 328 and 343 K for CO2 gas compositions not exceeding 18% at 1 bar, and a phenomenological Kinetic model was proposed to fit the carbonation conversion data obtained. Time-dependent carbonation conversions of the sorbent appeared as sigmoid curves. Sigmoid characteristics of the conversion curve were more pronounced for the sorption reaction at lower temperature and lower gas phase concentration of CO2. Such conversion behavior of fresh-dried K2CO3/ZrO2 sorbent could be closely described with the reaction rate equation in the form: r = kf(X)yCO2n . The reaction rate constant k as a temperature dependent term could be represented by Arrhenius’ equation with the negative apparent activation energy of −17.43 kJ/mol and the pre-exponential factor of 3.83 × 10–3 1/min. The term f(X) was a function introduced to reflect the carbonation rate change...
Kiran Prajapati - One of the best experts on this subject based on the ideXlab platform.
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p nitrobenzyltriphenyl phosphonium ylide initiated radical terpolymerization of styrene methyl methacrylate and acrylonitrile synthesis characterization and properties
Polymer International, 2007Co-Authors: Kiran Prajapati, Anuradha VarshneyAbstract:Solution terpolymerization of styrene (St), methyl methacrylate (MMA) and acrylonitrile (AN) was carried out in dioxane at 65 ± 0.1 °C for 120 min using p-nitrobenzyltriphenyl phosphonium ylide as radical initiator. The Kinetic Expression is as follows (Rp is the rate of polymerization): Rp∝ [ylide]0.45[St]0.8[MMA]1.2[AN]1.2. The overall activation energy is 42 kJ mol−1 L−1. The composition of terpolymer, calculated from 1H NMR and elemental analysis, was used to evaluate reactivity ratio, as r1 (MMA + AN) = 0.06 and r2 (St) = 0.005, employing the Kelen–Tudos method. It confirmed the alternating nature of the terpolymer. The terpolymer was characterized using 13C NMR, gel permeation chromatography and thermogravimetric differential thermal analysis. Electron spin resonance spectroscopy confirmed the presence of the phenyl radical responsible for initiation. Copyright © 2006 Society of Chemical Industry
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p‐Nitrobenzyltriphenyl phosphonium ylide‐initiated radical terpolymerization of styrene, methyl methacrylate and acrylonitrile: synthesis, characterization and properties
Polymer International, 2006Co-Authors: Kiran Prajapati, Anuradha VarshneyAbstract:Solution terpolymerization of styrene (St), methyl methacrylate (MMA) and acrylonitrile (AN) was carried out in dioxane at 65 ± 0.1 °C for 120 min using p-nitrobenzyltriphenyl phosphonium ylide as radical initiator. The Kinetic Expression is as follows (Rp is the rate of polymerization): Rp∝ [ylide]0.45[St]0.8[MMA]1.2[AN]1.2. The overall activation energy is 42 kJ mol−1 L−1. The composition of terpolymer, calculated from 1H NMR and elemental analysis, was used to evaluate reactivity ratio, as r1 (MMA + AN) = 0.06 and r2 (St) = 0.005, employing the Kelen–Tudos method. It confirmed the alternating nature of the terpolymer. The terpolymer was characterized using 13C NMR, gel permeation chromatography and thermogravimetric differential thermal analysis. Electron spin resonance spectroscopy confirmed the presence of the phenyl radical responsible for initiation. Copyright © 2006 Society of Chemical Industry
Ali Mirzaei - One of the best experts on this subject based on the ideXlab platform.
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fischer tropsch synthesis development of Kinetic Expression for a sol gel fe ni al2o3 catalyst
Fuel Processing Technology, 2012Co-Authors: Majid Sarkari, Farhad Fazlollahi, Hossein Atashi, Ali Mirzaei, Vahid HosseinpourAbstract:Abstract In this experimental study, a Kinetic model has been developed for Fischer–Tropsch synthesis reactions by using sol–gel technique and Fe/Ni/Al 2 O 3 as the catalyst (40% Fe/60% Ni/40 wt.%Al 2 O 3 ) in a differential fixed-bed micro reactor assuming no internal or external diffusion. Operating conditions of the reactor were as follows: total pressure 1–12 atm ; Temperature 220–260 °C; H 2 /CO feed ratio 1.5–2; gas hourly space velocity 2100–7000 cm 3 (STP)/h/g cat and conversions of 6–37% of hydrogen and 7–21% of carbon monoxide. Mass transfer limitations were investigated by changing synthesis gas velocity in reactors which differ in size. Based on the hypothesis that water inhibits the intrinsic Fischer–Tropsch (FT) reaction rate in the iron-FT synthesis, all rate Expressions in this study were in inverse ratio to number of vacant sites and CO and water content. The obtained data in this study were checked using “complete form of Langmuir–Hinshelwood–Hougan–Watson (LHHW)” which has been proposed by Van der Laan and Botes. The Kinetic parameters were determined using Levenberg–Marquardt (LM) method. The activation energy and heat of adsorption of CO and water were 103.81, − 56.82 and − 25.62 kJ/mol, respectively.
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an investigation of the Kinetics and mechanism of fischer tropsch synthesis on fe co mn supported catalyst
Fuel Processing Technology, 2012Co-Authors: Maryam Arsalanfar, Hossein Atashi, Ali Mirzaei, Hamid Reza Bozorgzadeh, Samaneh Vahid, A ZareAbstract:Abstract The Kinetic of the Fischer–Tropsch synthesis over a Fe–Co–Mn catalyst was investigated in a fixed bed micro reactor. Experimental conditions were varied as follow: reaction pressure 1–10 bar, H 2 /CO feed ratio of 1–3 and space velocity of 4500 h − 1 at the temperature range of 290–320 °C. 18 models according to the Langmuir–Hinshelwood–Hougen–Watson (LHHW) type rate equation were derived on the basis of detailed set of possible reaction mechanisms, and the reaction rate of this study is fitted fairly well by one Kinetic Expression based on LHHW mechanism. The Kinetic parameters were estimated with non-linear regression method and the activation energy was 82.520 kJ/mol for optimal Kinetic model. The catalyst characterization was carried out using different methods including powder X-Ray Diffraction (XRD) and Brunauer–Emmett–Teller (BET) surface area measurements.
