scholarly journals Evaluation of Thermal Evolution Profiles and Estimation of Kinetic Parameters for Pyrolysis of Coal/Corn Stover Blends Using Thermogravimetric Analysis

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Abhijit Bhagavatula ◽  
Gerald Huffman ◽  
Naresh Shah ◽  
Rick Honaker
Keyword(s):  
Thermogravimetric Analysis ◽  
Kinetic Parameters ◽  
Corn Stover ◽  
Thermal Evolution ◽  
Reaction Model ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Temperature Regimes ◽  
Lignite Coal

The thermal evolution profiles and kinetic parameters for the pyrolysis of two Montana coals (DECS-38 subbituminous coal and DECS-25 lignite coal), one biomass sample (corn stover), and their blends (10%, 20%, and 30% by weight of corn stover) have been investigated at a heating rate of 5°C/min in an inert nitrogen atmosphere, using thermogravimetric analysis. The thermal evolution profiles of subbituminous coal and lignite coal display only one major peak over a wide temperature distribution, ~152–814°C and ~175–818°C, respectively, whereas the thermal decomposition profile for corn stover falls in a much narrower band than that of the coals, ~226–608°C. The nonlinearity in the evolution of volatile matter with increasing percentage of corn stover in the blends verifies the possibility of synergistic behavior in the blends with subbituminous coal where deviations from the predicted yield ranging between 2% and 7% were observed whereas very little deviations (1%–3%) from predicted yield were observed in blends with lignite indicating no significant interactions with corn stover. In addition, a single first-order reaction model using the Coats-Redfern approximation was utilized to predict the kinetic parameters of the pyrolysis reaction. The kinetic analysis indicated that each thermal evolution profile may be represented as a single first-order reaction. Three temperature regimes were identified for each of the coals while corn stover and the blends were analyzed using two and four temperature regimes, respectively.

Kinetics of Cs adsorption/desorption on granite by a pseudo first order reaction model

2007 ◽  
Vol 275 (3) ◽  
pp. 555-562 ◽  
Author(s):  
Shih-Chin Tsai ◽  
Tsing-Hai Wang ◽  
Yuan-Yaw Wei ◽  
Wen-Chun Yeh ◽  
Yi-Lin Jan ◽  
...  
Keyword(s):  
Reaction Model ◽  
Order Reaction ◽  
First Order Reaction ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Pseudo First Order ◽  
Adsorption Desorption ◽  
Kinetics Of

A Method for Estimation of Kinetic Parameters; A Simple First-Order Reaction and Two Parallel First-Order Reactions Producing a Common Product

1992 ◽  
Vol 57 (6) ◽  
pp. 1196-1200
Author(s):  
Xizun Wu ◽  
Wenzhi Zhang ◽  
Shengmin Cai ◽  
Degang Han
Keyword(s):  
Differential Equation ◽  
Ordinary Differential Equation ◽  
Kinetic Parameters ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Kinetic System

A method is proposed for the treatment of data from a kinetic system of a simple first-order reaction and two parallel first-order reactions, producing a common product. It is based on the solving of a contrary proposition for an ordinary differential equation.

scholarly journals Kajian Dehidroksilasi Termal Kaolin menjadi Metakaolin menggunakan Analisis Termogravimetri

2021 ◽  
Vol 17 (1) ◽  
pp. 105
Author(s):  
Aprilina Purbasari ◽  
Tjokorde Walmiki Samadhi
Keyword(s):  
Fourier Transform ◽  
Thermogravimetric Analysis ◽  
Fourier Transform Infrared ◽  
Reaction Model ◽  
Order Reaction ◽  
X Ray Diffraction ◽  
Exponential Factor ◽  
X Ray ◽  
First Order ◽  
Air Atmosphere

<p>Kaolin merupakan mineral yang banyak dimanfaatkan di berbagai industri. Kaolin dapat diubah menjadi metakaolin yang lebih reaktif melalui proses dehidroksilasi termal. Pada penelitian ini, proses dehidroksilasi termal kaolin dari Bangka Belitung menjadi metakaolin dikaji menggunakan analisis termogravimetri pada rentang suhu 30 – 900 °C dengan laju pemanasan 10 °C/menit dalam lingkungan atmosfer udara. Kaolin mengalami empat tahap dekomposisi dan dehidroksilasi kaolin menjadi metakaolin terjadi pada suhu sekitar 450 – 600 °C. Berdasarkan metode Coats dan Redfern, dehidroksilasi kaolin mengikuti model reaksi order satu dengan energi aktivasi 271,66 kJ/mol dan faktor pre-eksponensial 6,13×10<sup>15</sup> s<sup>-1</sup>. Hasil analisis menggunakan spektroskopi <em>X-ray diffraction</em> (XRD) dan <em>Fourier Transform Infrared </em>(FTIR) pada kaolin setelah dipanaskan pada suhu 550 °C selama 3 jam menunjukkan bahwa sebagian besar kaolin telah berubah menjadi metakaolin.</p><p><strong>Study of Thermal Dehydroxylation of Kaolin to Metakaolin using Thermogravimetric Analysis. </strong>Kaolin is a mineral that is widely used in various industries. Kaolin can be converted into metakaolin which is more reactive through thermal dehydroxylation processes. In this study, thermal dehydroxylation process of Bangka Belitung kaolin into metakaolin was studied using thermogravimetric analysis in a temperature range of 30 – 900 °C with a heating rate of 10 <sup>o</sup>C/min in an air atmosphere condition. Kaolin underwent four stages of decomposition and dehydroxylation of kaolin into metakaolin occured at temperatures around 450 – 600 °C. Based on the Coats and Redfern method, kaolin dehydroxylation followed first order reaction model with activation energy of 271.66 kJ/mol and pre-exponential factor of 6.13×10<sup>15</sup> s<sup>-1</sup>. The analysis using X-ray diffraction (XRD) dan Fourier Transform Infrared (FTIR) spectroscopy on kaolin after heating at temperature of 550 °C for 3 hours showed that most of the kaolin had turned into metakaolin.</p>

Oxidation Chemistry of Primary and Secondary Antioxidants

2005 ◽  
Author(s):  
T. E. Karis ◽  
M. D. Carter
Keyword(s):  
Heat Flow ◽  
Heating Rate ◽  
Combustion Temperature ◽  
Reaction Model ◽  
Order Reaction ◽  
First Order Reaction ◽  
Heat Flow Rate ◽  
Base Oil ◽  
First Order ◽  
End Use

Inhibition of oil oxidation is the key to long life of synthetic lubricants operating in thermal stress and boundary lubrication environments [1]. Bench-scale tests to screen oil formulations provide a rapid means for optimizing formulations prior to longer running verification tests done with the oil in the end-use application [2]. The ultimate goal of accelerated oil life tests is to link the sample combustion temperature, or induction time, at a given heating rate, or temperature, to the estimated lifetime under normal use temperatures. A first order reaction model has recently been employed to derive kinetic parameters from the heating rate dependence of the combustion temperature in the non-isothermal pressure DSC (NIPDSC) test by Adhvaryu et al. [3]. The first order reaction model [4] is also employed here, but we show that a more detailed scheme is needed to fit the heat flow during the combustion exotherm. The detailed kinetic model also provides the link between the NIPDSC test and the isothermal pressure DSC test, as well lifetime estimation at temperatures closer to the end-use conditions. Although isothermal PDSC is useful on grease [5], it does not provide a sharp exotherm for the unthickened base oil [6]. The NIPDSC test provides a reasonably sharp exotherm for formulated base oil in a relatively short amount of time. In the NIPDSC test, 10–12 mg of oil is placed in an open DSC pan. The sample chamber is pressurized with oxygen. The sample temperature is linearly increased with time until the occurrence of the combustion exotherm. The exotherm peak temperature and total heat flow did not exhibit any regular dependence on oxygen pressure between 0.55 and 3.4 MPa. The base oil was an (average) C7 ester of pentaerythritol. Primary antioxidants were hindered phenol and aromatic amines, and Zn-dialkyldithiocarbamate (ZDTC) and Zn-dialkyldithiophosphate (ZDDP) were used as secondary antioxidants. For some of the tests, soluble catalyst [2] was incorporated as iron (III) 2-ethylhexanoate. The reduced heat flow thermograms during the NIPDSC test on the base oil are shown in Fig. 1. The curves are normalized by the peak heat flow rate as Q/Qp, and the symbols denote curves from the first order reaction model, discussed below. The exotherm temperature increases and the exotherm sharpens with increased heating rate. At the 20 °C/min heating rates, the internal heating upon combustion noticeably skews the shape of the exotherm.

Biosorption of cationic dyes by dead macro fungus fomitopsis carnea: batch studies

1996 ◽  
Vol 34 (10) ◽  
pp. 81-87 ◽  
Author(s):  
Atul K. Mittal ◽  
S. K. Gupta
Keyword(s):  
Reaction Kinetics ◽  
Kinetic Parameters ◽  
Order Reaction ◽  
Cationic Dyes ◽  
First Order Reaction ◽  
Sorption Kinetic ◽  
Batch Studies ◽  
First Order ◽  
Sorption Potential

Application of dead macrofungus, Fomotopsis carnea for the sorption of three cationic dyes viz., Orlamar Red BG (ORBG), Orlamar Blue G (OBG) and Orlamar Red GTL (ORGTL) has been investigated. This study mainly focuses on the effect of various sorption kinetic parameters for the uptake of ORBG. Fomitopsis carnea shows excellent sorption potential for all the dyes studied. Saturation capacities for ORBG, OBG and ORGTL are 503.1, 545.2 and 643.9 mg g−1 respectively. Biosorption in the batch adsorber can be described by first-order reaction kinetics. Sorption decreases with decrease in pH.

scholarly journals GASIFICATION STUDY OF SARAWAK COALS

2017 ◽  
Vol 25 (1) ◽  
pp. 67-72
Author(s):  
Nor Fadzilah Othman ◽  
Mohd Hariffin Bosrooh
Keyword(s):  
Activation Energy ◽  
Kinetic Parameters ◽  
Arrhenius Equation ◽  
Preliminary Investigation ◽  
Reaction Model ◽  
Order Reaction ◽  
Low Rank ◽  
Heating Rates ◽  
First Order ◽  
Air Atmosphere

Thermogravimetry (TG) has been applied in a preliminary investigation, to the gasification of two low rank Sarawak coals. The coal samples, about 10 mg were investigated within the temperature range 30–900°C at different heating rate of 10, 20 and 30°C min-1, under a synthetic air atmosphere for the gasification study. The kinetic parameters were determined using Arrhenius type reaction model assuming a first-order reaction. The reactivity, RT values are fitted with Arrhenius equation at r2 = 0.83 - 0.98 for MP coal, while the RT values for MB coal are fitted with the Arrhenius equation at r2 = 0.99. The activation energy, EA for MP coal are in the range of 3.7 -4.7 kJ mol-1 and for MB coal are 7.6 - 25.6 kJ mol-1 at 3 different heating rates.  

Leaching Kinetics of Atrazine and Inorganic Chemicals in Tilled and Orchard Soils

2014 ◽  
Vol 28 (2) ◽  
pp. 231-237 ◽  
Author(s):  
Lech W. Szajdak ◽  
Jerzy Lipiec ◽  
Anna Siczek ◽  
Artur Nosalewicz ◽  
Urszula Majewska
Keyword(s):  
Reaction Rate ◽  
Inorganic Compounds ◽  
Model Performance ◽  
Order Reaction ◽  
First Order Reaction ◽  
Order Kinetic ◽  
Time Data ◽  
First Order ◽  
Concentration Changes ◽  
Reaction Constants

Abstract The aim of this study was to verify first-order kinetic reaction rate model performance in predicting of leaching of atrazine and inorganic compounds (K+1, Fe+3, Mg+2, Mn+2, NH4 +, NO3 - and PO4 -3) from tilled and orchard silty loam soils. This model provided an excellent fit to the experimental concentration changes of the compounds vs. time data during leaching. Calculated values of the first-order reaction rate constants for the changes of all chemicals were from 3.8 to 19.0 times higher in orchard than in tilled soil. Higher first-order reaction constants for orchard than tilled soil correspond with both higher total porosity and contribution of biological pores in the former. The first order reaction constants for the leaching of chemical compounds enables prediction of the actual compound concentration and the interactions between compound and soil as affected by management system. The study demonstrates the effectiveness of simultaneous chemical and physical analyses as a tool for the understanding of leaching in variously managed soils.

The Kinetics of Glucose Decomposition with Sulfate Reduction in the Anaerobic Fluidized Bed Reactor

1993 ◽  
Vol 28 (2) ◽  
pp. 135-144 ◽  
Author(s):  
S. Matsui ◽  
R. Ikemoto Yamamoto ◽  
Y. Tsuchiya ◽  
B. Inanc
Keyword(s):  
Sulfate Reduction ◽  
Fluidized Bed ◽  
Kinetic Equations ◽  
Fluidized Bed Reactor ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Glucose Decomposition ◽  
Reaction Equations ◽  
Kinetics Of

Using a fluidized bed reactor, experiments on glucose decomposition with and without sulfate reduction were conducted. Glucose in the reactor was mainly decomposed into lactate and ethanol. Lactate was mainly decomposed into propionate and acetate, while ethanol was decomposed into propionate, acetate, and hydrogen. Sulfate reduction was not involved in the decomposition of glucose, lactate, and ethanol, but was related to propionate and acetate decomposition. The stepwise reactions were modeled using either a Monod expression or first order reaction kinetics in respect to the reactions. The coefficients of the kinetic equations were determined experimentally. The modified Monod and first order reaction equations were effective at predicting concentrations of glucose, lactate, ethanol, propionate, acetate, and sulfate along the beight of the reactor. With sulfate reduction, propionate was decomposed into acetate, while without sulfate reduction, accumulation of propionate was observed in the reactor. Sulfate reduction accelerated propionate conversion into acetate by decreasing the hydrogen concentration.

Complete monotonicity of entropy production in chemical reaction

1981 ◽  
Vol 46 (2) ◽  
pp. 452-456
Author(s):  
Milan Šolc
Keyword(s):  
Entropy Production ◽  
Equilibrium Constant ◽  
Chemical Reaction ◽  
Relative Entropy ◽  
Order Reaction ◽  
Complete Monotonicity ◽  
First Order Reaction ◽  
First Order ◽  
Completely Monotonic ◽  
Derivatives Of

The successive time derivatives of relative entropy and entropy production for a system with a reversible first-order reaction alternate in sign. It is proved that the relative entropy for reactions with an equilibrium constant smaller than or equal to one is completely monotonic in the whole definition interval, and for reactions with an equilibrium constant larger than one this function is completely monotonic at the beginning of the reaction and near to equilibrium.

Kinetics and Mechanism of Hexachloroiridate(IV) Oxidation of Arsenic(III) in Acidic Perchlorate Solutions

1992 ◽  
Vol 57 (7) ◽  
pp. 1451-1458 ◽  
Author(s):  
Refat M. Hassan
Keyword(s):  
Ionic Strength ◽  
Fractional Order ◽  
Activation Parameters ◽  
Order Reaction ◽  
First Order Reaction ◽  
Intermediate Complex ◽  
Constant Ionic Strength ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Kinetics Of

The kinetics of oxidation of arsenic(III) by hexachloroiridate(IV) at lower acid concentrations and at constant ionic strength of 1.0 mol dm-3 have been investigated spectrophotometrically. A first-order reaction in [IrCl62-] and fractional order with respect to arsenic(III) have been observed. A kinetic evidence for the formation of an intermediate complex between the hydrolyzed arsenic(III) species and the oxidant was presented. The results showed that decreasing the [H+] is accompanied by an appreciable acceleration of the rate of oxidation. The activation parameters have been evaluated and a mechanism consistent with the kinetic results was suggested.

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