scholarly journals Kinetics of the sunflower oil ethanolysis using CaO as catalyst

2016 ◽  
Vol 22 (4) ◽  
pp. 409-418 ◽  
Author(s):  
Ana Velickovic ◽  
Jelena Avramovic ◽  
Olivera Stamenkovic ◽  
Vlada Veljkovic
Keyword(s):  
Kinetic Model ◽  
Sunflower Oil ◽  
Reaction Rate Constant ◽  
Ethyl Esters ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Reaction Conditions ◽  
Data Points ◽  
Kinetics Of ◽  
Good Agreement

The ethanolysis of sunflower oil catalyzed by calcium oxide was studied in wider ranges of the reaction conditions: temperature 65-75?C, ethanol-to-oil molar ratio 6:1-18:1 and catalyst loading 10-20% in order to determine the reaction kinetics. The proposed kinetic model of the sunflower oil ethanolysis included the changing and first-order reaction mechanism with respect to triacylglycerols and fatty acid ethyl esters. The kinetic parameters were determined and correlated with the process variables. The Arrhenius equation could be applied to the reaction rate constant with the activation energy of 94.0 kJ/mol. The proposed kinetic model showed a good agreement with the experimental data with the mean relative percentage deviation of ?13% (based on 256 data points).

scholarly journals Further study on kinetic modeling of sunflower oil methanolysis catalyzed by calcium-based catalysts

2016 ◽  
Vol 22 (2) ◽  
pp. 137-144 ◽  
Author(s):  
Marija Miladinovic ◽  
Marija Tasic ◽  
Olivera Stamenkovic ◽  
Vlada Veljkovic ◽  
Dejan Skala
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Kinetic Model ◽  
Sunflower Oil ◽  
Coefficient Of Determination ◽  
Reaction Conditions ◽  
High Coefficient ◽  
Relative Percentage ◽  
Kinetics Of ◽  
Good Agreement

The kinetic model, which was originally developed for sunflower oil methanolysis catalyzed by CaO.ZnO, was examined for several other calcium-based catalysts like neat CaO, quicklime and Ca(OH)2. This model including triacylglycerols mass transfer- and chemically-controlled regimes demonstrated a good agreement with the experimental data in terms of a high coefficient of determination (0.971?0.022) and acceptable mean relative percentage deviation (?15.9%). Hence, this model is recommended for modeling the kinetics of sunflower oil methanolysis over calcium-based catalysts under widely ranging reaction conditions.

scholarly journals Kinetics of heterogeneous methanolysis of sunflower oil with CaO∙ZnO catalyst: Influence of different hydrodynamic conditions

2014 ◽  
Vol 20 (3) ◽  
pp. 425-439 ◽  
Author(s):  
Ivana Lukic ◽  
Zeljka Kesic ◽  
Svetolik Maksimovic ◽  
Miodrag Zdujic ◽  
Jugoslav Krstic ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Rate Constant ◽  
Sunflower Oil ◽  
Reaction Rate ◽  
Catalyst Surface ◽  
Reaction Rate Constant ◽  
Molar Ratio ◽  
Model Parameters ◽  
Pseudo First Order Reaction ◽  
Kinetics Of

The kinetics of heterogeneous methanolysis of sunflower oil was studied at 60?C using mechanochemically synthesized CaO?ZnO as catalyst. Influence of agitation speed, catalyst amount and methanol to oil molar ratio on the rate of reaction was analyzed. The rate of the process depends on the two resistances - mass transfer of triglycerides to the catalyst surface and chemical reaction on the catalyst surface, which are defined as the values of the overall triglyceride volumetric mass transfer coefficient, kmt,TG, and the effective pseudo first-order reaction rate constant, k, respectively. These kinetic parameters actually determine the value of the apparent reaction rate constant, kapp, whose change with time is defined with the change of triglyceride (TG) conversion. The kinetic model was proposed and the model parameters determined.

scholarly journals Kinetic modeling of canola oil transesterification catalyzed by quicklime

2018 ◽  
Vol 16 (6) ◽  
Author(s):  
J.N. Camacho ◽  
G. E. Galván Muciño ◽  
S.L. Martínez Vargas ◽  
C. Pérez Alonso ◽  
R. Natividad
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Canola Oil ◽  
Reaction Rate ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Minor Effect ◽  
Whole Process ◽  
High Effect ◽  
Kinetics Of

This work aimed to study and model the kinetics of transesterification of canola oil with methanol catalyzed by calcined quicklime (CaO + MgO). The influence of three main variables was studied at 328 K: reagents order addition (has a negligible effect on the reaction), methanol-oil molar ratio (has minor effect on reaction rate after 1.5 h of reaction) and catalyst loading (high effect on reaction rate) to achieve at least a triglycerides conversion of 96.5% in concordance with norm EN 14103. A kinetic model based on an Eley-Rideal mechanism was found to well fit (R2 = 0.9886) the experimental data. Thus, it was concluded that for the quicklime catalyzed transesterification of canola oil with methanol to occur, first the methanol must be chemisorbed and the resulting methoxy species react with triglycerides in the interface liquid-solid. The whole process is limited by this step since methanol readily adsorbs onto the catalytic surface.

scholarly journals Relevance of the Physicochemical Properties of Calcined Quail Eggshell (CaO) as a Catalyst for Biodiesel Production

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Leandro Marques Correia ◽  
Juan Antonio Cecilia ◽  
Enrique Rodríguez-Castellón ◽  
Célio Loureiro Cavalcante ◽  
Rodrigo Silveira Vieira
Keyword(s):  
Sunflower Oil ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
X Ray ◽  
Activity Phase ◽  
Temperature Programmed ◽  
Adsorption Desorption

The CaO solid derived from natural quail eggshell was calcined and employed as catalyst to produce biodiesel via transesterification of sunflower oil. The natural quail eggshell was calcined at 900°C for 3 h, in order to modify the calcium carbonate present in its structure in CaO, the activity phase of the catalyst. Both precursor and catalyst were characterized using Hammett indicators method, X-ray fluorescence (XRF), X-ray diffraction (XRD), thermogravimetric analysis (TG/DTG), CO2temperature-programmed desorption (CO2-TPD), X-ray photoelectronic spectroscopy (XPS), Fourier infrared spectroscopy (FTIR), scanning electron microscopy (SEM), N2adsorption-desorption at −196°C, and distribution particle size. The maximum biodiesel production was of 99.00 ± 0.02 wt.% obtained in the following transesterification reaction conditions:XMR(sunflower oil/methanol molar ratio of 1 : 10.5 mol : mol),XCAT(catalyst loading of 2 wt.%),XTIME(reaction time of 2 h), stirring rate of 1000 rpm, and temperature of 60°C.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

scholarly journals Kinetics of Transesterification of Safflower Oil to Obtain Biodiesel Using Heterogeneous Catalysis

2016 ◽  
Vol 14 (4) ◽  
pp. 929-938 ◽  
Author(s):  
Gabriel E. Galván Muciño ◽  
Rubi Romero ◽  
Armando Ramírez ◽  
María Jesús Ramos ◽  
Ramiro Baeza-Jiménez ◽  
...  
Keyword(s):  
Experimental Data ◽  
Statistical Analysis ◽  
Heterogeneous Catalysis ◽  
Kinetic Model ◽  
Methyl Esters ◽  
Molar Ratio ◽  
Safflower Oil ◽  
Estimated Parameters ◽  
Kinetics Of ◽  
Best Fit

Abstract The kinetics of the transesterification of safflower oil and methanol catalyzed by K2O/NaX was studied and modeled. The influence of the oil-methanol initial molar ratio and amount of catalyst were investigated to achieve a maximum triglycerides conversion (99 %) and a final methyl esters content of 94 % ±1. A kinetic model based on an Eley–Rideal mechanism was found to best fit the experimental data when assuming methanol adsorption as determining step. Other models derived from Langmuir – Hinshelwood – Hougen –Watson (LHHW) mechanisms were rejected based on statistical analysis, mechanistic considerations and physicochemical interpretation of the estimated parameters.

Kinetics and Modelling of Bulk and Solution Diallyl Terephthalate Polymerization

2006 ◽  
Vol 4 (1) ◽  
Author(s):  
Iztok Hace
Keyword(s):  
Kinetic Model ◽  
Kinetic Parameters ◽  
Rate Constants ◽  
Chain Transfer ◽  
Average Molecular Weight ◽  
Propagation Rate ◽  
Reaction Conditions ◽  
Diffusion Limitations ◽  
Kinetics Of ◽  
Dicyclohexyl Peroxydicarbonate

Free radical polymerization kinetics of diallyl terephthalate (DAT) in solution was investigated with two different peroxide initiators: dicyclohexyl peroxydicarbonate (CHPC) and benzoyl peroxide (BPO) in temperature range from 50°C to 110°C, where ortho-xylene was used as a solvent. Conversion points were measured using Fourier Transform Infrared (FTIR) measurements. Previously developed kinetic model for bulk DAT polymerization, was extended to solution DAT polymerization. The ratio of solvent chain - transfer rate constants to propagation rate constants of the polymerization system were found between 1.25 10-4 to 1.68 10-4 for various reaction conditions. They were obtained using the calculated initial polymerization rates and the number average molecular weight measurements made by GPC. The effect of different solvent fractions and initiator concentrations on the diffusion limitations were investigated. Only two kinetic parameters, kpd0 and ktd0 were obtained by fitting the kinetic model onto measured conversions for various reaction conditions at 0.2, 0.5 and 0.8 solvent fractions. Thus obtained kpd0 and ktd0 kinetic parameters were extrapolated to zero solvent fractions and from obtained values of kinetic parameters the conversion points for bulk DAT polymerization were calculated and compared to measured conversion points.

scholarly journals Laboratory-Scale Research of Non-Catalyzed Supercritical Alcohol Process for Continuous Biodiesel Production

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 435
Author(s):  
Aso A. Hassan ◽  
Joseph D. Smith
Keyword(s):  
Plug Flow ◽  
Tubular Reactor ◽  
Volumetric Flow Rate ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Supercritical Methanol ◽  
Setup Cost ◽  
Reaction Conditions ◽  
Reactor Technology ◽  
Kinetics Of

This work investigates the non-catalyzed supercritical methanol (SCM) process for continuous biodiesel production. The lab-scale setup was designed and used for biodiesel production in the temperature range of 520–650 K and 83–380 bar with an oil-to-methanol molar ratio ranging from 1:5 to 1:45. The experiments were performed in the coiled plug flow tubular reactor. The volumetric flow rate of the methanol/oil ranged from 0.1–10 mL/min. This work examines a new reactor technology involving preheating and pre-mixing of the methanol/oil mixture to reduce setup cost and increase biodiesel yield under the same reaction conditions. Work performed showed that FAME’s yield increased rapidly with temperature and pressure above the methanol critical points (i.e., 513 K and 79.5 bar). The best methyl-ester yield using this reaction technology was 91% at 590 K temperature and 351 bars with an oil-to-methanol ratio of 39 and a 15-min residence time. Furthermore, the kinetics of the free catalyst transesterification process was studied in supercritical methanol under different reaction conditions.

Pyrolysis of Sugarcane Bagasse: A Consecutive Reactions Kinetic Model from TGA Experiments

2010 ◽  
Vol 660-661 ◽  
pp. 593-598 ◽  
Author(s):  
Kássia Graciele dos Santos ◽  
Taisa S. Lira ◽  
Valéria V. Murata ◽  
Marco Gianesella ◽  
Marcos A.S. Barrozo
Keyword(s):  
Kinetic Model ◽  
Sugarcane Bagasse ◽  
Room Temperature ◽  
Linear Method ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Exponential Factor ◽  
Consecutive Reactions ◽  
Kinetics Of ◽  
Good Agreement

The pyrolysis kinetics of sugarcane bagasse in nitrogen flow was studied by thermogravimetric analysis from room temperature to 1173 K at different heating rates (1.5, 3, 5, 10, 15, 20, 30 and 50 K/min). As there are three distinct devolatilization peaks in the DTG curve, each peak was associated to thermal decomposition of an individual biomass subcomponent (hemicellulose, cellulose and lignin). The kinetic model adopted was a consecutive reactions model. The kinetic parameters of the pyrolysis process, such as activation energy and pre-exponential factor, were calculated by least squares non-linear method and Scilab are used as the simulation tool. The simulated results showed a good agreement with the experimental data and the parameters found are similar to reported by the literature.

scholarly journals Sulfonated Hydrothermal Carbon-Based Catalyzed Esterification under Microwave Irradiation: Optimization and Kinetic Study

2020 ◽  
Vol 15 (2) ◽  
pp. 514-524
Author(s):  
Laddawan Tumkot ◽  
Armando T. Quitain ◽  
Tetsuya Kida ◽  
Navadol Laosiripojana ◽  
Artiwan Shotipruk ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Reaction Rate Constant ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Esterification Reaction ◽  
Good Prediction ◽  
Molar Ratios ◽  
First Order Kinetics ◽  
A Value ◽  
Carbon Based

In this study, the esterification reaction of oleic acid (OA) with methanol was investigated in the presence of a sulfonated hydrothermal carbon-based catalyst under microwave irradiation. The reaction conditions were optimized using response surface methodology based on a central composite design. Three following variables were studied: methanol to OA molar ratios (2.5:1–7.5:1), reaction time (50–70 min) and catalyst loading (2–5 wt.%) to provide a statistical model with the coefficient of regression (R2) of 0.9407. Based on the model, the optimum OA conversion of 95.6% was predicted at 5.8:1 methanol to OA molar ratio, 60 min and 3.05 wt.% catalyst loading. The experimental validation indicated that the model gave a good prediction of OA conversion (2.8% error). Furthermore, the reaction was found to be reasonably described by the pseudo-first order kinetics. The dependency of the reaction rate constant on temperatures gave a value of the activation energy of 64 kJ/mol. Copyright © 2020 BCREC Group. All rights reserved 

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