scholarly journals EVALUASI KINETIKA DEKOMPOSISI TERMAL PROPELAN KOMPOSIT AP/HTPB DENGAN METODE KISSINGER, FLYNN WALL OZAWA DAN COATS - REDFREN

2018 ◽  
Vol 15 (2) ◽  
pp. 115
Author(s):  
Wiwiek Utami Dewi
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Catalytic Effect ◽  
Nitrogen Atmosphere ◽  
Decomposition Kinetic ◽  
Exponential Factor ◽  
Random Nucleation ◽  
Mechanism And Kinetics ◽  
The Individual ◽  
Individual Particles

Decomposition of propellant Mechanism and kinetics have been investigated by using DTG/TA with three different methods: Kissinger, Flynn Wall Ozawa and Coats & Redfern. This research aims to determine decomposition kinetic parameters of LAPAN’s propellant. The propellants have different composition of Al and AP modal. RUM propellant consist of AP/HTPB. 450 propellant consists AP/HTPB/Al (bimodal). Meanwhile 1220 propellant consists of AP/HTPB/Al (trimoda). Thermal analysis takes place at 30 – 400oC and nitrogen atmosphere flow rate is 50 ml/min. The result according showed that propellant was decomposed by F1 mechanism (random nucleation with one nucleus on the individual particles). Activation energy of propellants are in range between 100.876 – 155.156 kJ/mol meanwhile pre-exponential factor are in range between 4.57 x 107 – 3.46 x 1012/min. Activation energy (E) as well as pre-exponential factor for 1220 propellant is the lowest among the others. AP trimodal application generates catalytic effect which decreases activation energy. 1220 propellant is easier to decompose (easier to react) than RUM and 450 propellant. AbstrakMekanisme dan kinetika dekomposisi propelan telah diinvestigasi menggunakan DTG/TA dengan tiga jenis metode yang berbeda yaitu Kissinger, Flynn Wall Ozawa dan Coats & Redfern. Penelitian ini bertujuan untuk mengetahui parameter kinetika dekomposisi propelan LAPAN. Propelan yang digunakan memiliki perbedaan komposisi Al dan jenis moda AP. Propelan RUM adalah propelan AP/HTPB. RX 450 adalah AP/HTPB/ Al (bimoda). Sementara itu, RX 1220 adalah AP/HTPB/ Al (trimoda). Pengujian termal berlangsung pada suhu 30 - 400oC dan atmosfer nitrogen berlaju alir 50 ml/menit. Hasil penelitian mengungkapkan bahwa semua jenis propelan terdekomposisi dengan mekanisme F1 (nukleasi acak dengan satu nukleus pada partikel individu). Energi aktivasi propelan berkisar antara 100,876 – 155,156 kJ/mol sementara faktor pre-eksponensial berkisar antara 4,57 x 107 – 3,46 x 1012/min. Energi aktivasi (E) dan faktor pre-eksponensial (A) RX 1220 adalah terendah dari ketiga sampel. Penggunaan jenis AP trimodul menciptakan efek katalitik yang menurunkan besarnya energi aktivasi. Propelan RX 1220 lebih mudah terdekomposisi (lebih mudah bereaksi) daripada propelan RUM dan RX 450. 

Studies on the Thermal Decomposition Kinetic of an Nitrate Ester

2012 ◽  
Vol 182-183 ◽  
pp. 1575-1580 ◽  
Author(s):  
Juan Wang ◽  
Da Bin Liu ◽  
Xin Li Zhou
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Decomposition Mechanism ◽  
Thermal Decomposition Mechanism ◽  
Decomposition Kinetic ◽  
Heating Rates ◽  
Exponential Factor ◽  
Nitrate Ester ◽  
Dynamic Function ◽  
Thermal Decomposition Kinetic

The certain nitrate ester explosive has been tested by TG at the heating rates of 10, 15, 20, 25K•min-1. Basing on the TG experiment results the thermal decomposition activation energy has been calculated by the methods of Ozawa, KAS and iteration. And the thermal decomposition mechanism function of the explosive with 38 kinds of dynamic function was deduced by the method of integration. The results show that the thermal decomposition mechanism of the nitrate ester is chemical reaction mechanism. The thermal decomposition kinetic parameters such as average activation energy Ea and pre-exponential factor A are 133.23×103 J•mol-1 and 3.191×107 s-1 respectively.

scholarly journals Thermal decomposition characteristics of foundry sand for cast iron in nitrogen atmosphere

2018 ◽  
Vol 5 (12) ◽  
pp. 181091 ◽  
Author(s):  
Qingwei Xu ◽  
Kaili Xu ◽  
Xiwen Yao ◽  
Jishuo Li ◽  
Li Li
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Cast Iron ◽  
Low Cost ◽  
Temperature Stability ◽  
Nitrogen Atmosphere ◽  
High Temperature Stability ◽  
Kinetics Parameters ◽  
Foundry Sand ◽  
Exponential Factor

Sand casting, currently the most popular approach to the casting production, has wide adaptability and low cost. The thermal decomposition characteristics of foundry sand for cast iron were determined for the first time in this study. Thermogravimetry was monitored by simultaneous thermal analyser to find that there was no obvious oxidation or combustion reaction in the foundry sand; the thermal decomposition degree increased as the heating rate increased. There was an obvious endothermic peak at about 846 K due to the transition of quartz from β to α phase. A novel technique was established to calculate the starting temperature of volatile emission in determining the volatile release parameter of foundry sand for cast iron. Foundry sand does not readily evaporate because its volatile content is only about 2.68 wt% and its main components have high-temperature stability. The thermal decomposition kinetics parameters of foundry sand, namely activation energy and pre-exponential factor, were obtained under kinetics theory. The activation energy of foundry sand for cast iron was small, mainly due to the wide temperature range of thermal decomposition in the foundry sand.

scholarly journals Thermal Analysis On The Kinetics Of Magnesium-Aluminum Layered Double Hydroxides In Different Heating Rates

2015 ◽  
Vol 60 (2) ◽  
pp. 1357-1359 ◽  
Author(s):  
Y. Hongbo ◽  
C. Meiling ◽  
W. Xu ◽  
G. Hong
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Layered Double Hydroxides ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Exponential Factor ◽  
Thermal Kinetic Parameters ◽  
Double Hydroxides ◽  
Kinetics Of ◽  
Dsc Curves

Abstract The thermal decomposition of magnesium-aluminum layered double hydroxides (LDHs) was investigated by thermogravimetry analysis and differential scanning calorimetry (DSC) methods in argon environment. The influence of heating rates (including 2.5, 5, 10, 15 and 20K/min) on the thermal behavior of LDHs was revealed. By the methods of Kissinger and Flynn-Wall-Ozawa, the thermal kinetic parameters of activation energy and pre-exponential factor for the exothermic processes under non-isothermal conditions were calculated using the analysis of corresponding DSC curves.

Thermal Cure and Ceramization Kinetics of Perhydropolysilazane

2013 ◽  
Vol 575-576 ◽  
pp. 81-86 ◽  
Author(s):  
Feng Ling Ma ◽  
Hui Min Qi ◽  
Ya Ping Zhu ◽  
Xiao Wen Ren ◽  
Fan Wang
Keyword(s):  
Activation Energy ◽  
Weight Loss ◽  
Thermogravimetric Analysis ◽  
Kinetic Parameters ◽  
Nitrogen Atmosphere ◽  
Thermal Cure ◽  
Exponential Factor ◽  
Kinetics Of

The kinetics of the thermal cure and ceramization of preceramic prehydropolysilazane (PHPS) was investigated by thermogravimetric analysis (TGA) under nitrogen atmosphere. The results indicated that the gases captured during the thermal cure and ceramization process of PHPS, which had three main weight loss events. The corresponding kinetic parameters including activation energy, pre-exponential factor and empirical order of the thermal cure and ceramization stages were evaluated by using Ozawa and Kissinger metnods, respectively.

scholarly journals Thermogravimetric kinetic study of solid recovered fuels pyrolysis

2018 ◽  
Vol 72 (2) ◽  
pp. 99-106 ◽  
Author(s):  
Milos Radojevic ◽  
Martina Balac ◽  
Vladimir Jovanovic ◽  
Dragoslava Stojiljkovic ◽  
Nebojsa Manic
Keyword(s):  
Thermal Analysis ◽  
Kinetic Parameters ◽  
Simultaneous Thermal Analysis ◽  
Experimental Tests ◽  
Nitrogen Atmosphere ◽  
Cement Industry ◽  
Thermochemical Conversion ◽  
Gravimetric Analysis ◽  
Heating Rates ◽  
Exponential Factor

In the Republic of Serbia there are significant quantities of coffee and tire wastes that can be utilized as Solid Recovered Fuel (SRF) and used as an additional fuel for co?combustion with coal and biomass in energy production and cement industry sectors. Differences between SRF and base fuel are a cause of numerous problems in design of burners. The objective of this study was to determine the kinetic parameters for the thermochemical conversion of selected SRF using Simultaneous Thermal Analysis (STA). Samples of coffee and tire waste were used for the experimental tests. Thermal analysis was carried out in nitrogen atmosphere at three different heating rates 10, 15 and 20 K/min for each sample, while it was heated from room temperature up to 900?C. Two sample sizes x <0.25 mm and 0.25 < x <0.5 mm of each SRF were used in experiments, in order to obtain reliable Thermal Gravimetric Analysis (TGA) data for estimation of kinetic parameters for SRF pyrolysis. Experimental results were used for determination of pre-exponential factor and activation energy according to methods presented in the literature. Presented research provides valuable data of coffee and tire waste that can be used for the burners design.

scholarly journals Physicochemical, Mineralogy, and Thermo-Kinetic Characterisation of Newly Discovered Nigerian Coals under Pyrolysis and Combustion Conditions

2020 ◽  
Author(s):  
Bemgba Bevan Nyakuma ◽  
Aliyu Jauro ◽  
Segun Ajayi Akinyemi ◽  
Hasan Mohd Faizal ◽  
Mohammed Baba Nasirudeen ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Energy Recovery ◽  
Major Elements ◽  
Industrial Applications ◽  
Physicochemical Analysis ◽  
Kinetic Properties ◽  
Exponential Factor ◽  
Minor Elements ◽  
Low Levels

Abstract In this study, the physicochemical, microstructural, mineralogical, thermal, and kinetic properties of three (3) newly discovered coals from Akunza (AKZ), Ome (OME), and Shiga (SHG) in Nigeria were examined for potential energy recovery. Physicochemical analysis revealed high combustible but low levels of polluting elements. The higher heating values (HHV) ranged from 18.65 MJ/kg (AKZ) to 26.59 MJ/kg (SHG). Microstructure and mineralogical analyses revealed particles with a rough texture, surfaces, and glassy lustre, which could be ascribed to metals, quartz, and kaolinite minerals. The major elements (C, O, Si, and Al), along with minor elements (Ca, Cu, Fe, K, Mg, S, and Ti) detected are associated with clays, salts, or the porphyrin constituents of coal. Thermal analysis showed mass loss (ML) ranges from 30.51% – 87.57% and residual mass (RM) from 12.44% – 69.49% under combustion (oxidative) and pyrolysis (non-oxidative) TGA conditions due to thermal degradation of organic matter, vitrinite, inertinite and liptinite macerals. Kinetic analysis revealed that the coal samples are highly reactive under the non-isothermal oxidative and non-oxidative conditions based on the Coats-Redfern Model. The activation energy (Ea) ranged from 23.81 kJ/mol – 89.56 kJ/mol whereas the pre-exponential factor (ko) ranged from 6.77×10 -04 min -1 – 1.72×10 03 min -1 under pyrolysis and combustion conditions. In conclusion, the coals are practical feedstocks for either industrial applications or energy recovery.

scholarly journals Kinetic Parameters for the Thermal Decomposition of Forest Waste Using Distributed Activation Energy Model (DAEM)

2017 ◽  
Vol 19 (1) ◽  
pp. 15-32 ◽  
Author(s):  
Alok Dhaundiyal ◽  
Pramod Tewari
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Thermal Decomposition ◽  
Asymptotic Expansion ◽  
Nitrogen Atmosphere ◽  
Energy Model ◽  
Pine Needle ◽  
Distributed Activation Energy Model ◽  
Exponential Factor ◽  
Forest Waste

Abstract The purview of paper pivoted around the pyrolysis decomposition of forest waste (pine needle litter) by thermogravimetric analysis (TGA). Experiments were carried out in the presence of Nitrogen atmosphere. The experimental data was compared with those obtained by numerical solution of distributed activation energy model (DAEM). Asymptotic expansion is adopted to evaluate the pre-exponential factor, mean activation energy and variance. The correction factor Bi has been invoked to describe accurately the differential thermogravitmeric curves of thermal decomposition of pine needles.

Study on Kinetics of Nano-Ni(OH)2 Powder Ethanol Desorption Process

2014 ◽  
Vol 1015 ◽  
pp. 509-512
Author(s):  
Feng Pan ◽  
Zai Yuan Li ◽  
Chun Ji Li
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Shape Factor ◽  
Peak Shape ◽  
Desorption Process ◽  
Exponential Factor ◽  
Mechanism Function ◽  
Thermal Analysis Kinetics ◽  
Kinetics Of ◽  
Tga Analysis

This paper studies on the thermal analysis kinetics of nanometer powders ethanol desorption process.The DTA-TG-DTG curves obtain by SDT 2960 Simultaneous DSC-TGA analysis apparatus. Under the condition of N2atmosphere operation and rise temperature velocity was 10°C·min-1. The mechanism functionis used to calculate the kinetics factors. Reaction progressionnwas obtained by calculation of the kissinger peak shape factor method. The results showed that the apparent activation energy of nano-Ni(OH)2was 73.210 kJ·mol-1, the pre-exponential factor was 2.349×1012, the reaction progression was obtained as 1.2767, the kinetic equation is

scholarly journals Comparison of the dehydration kinetics of solid state compounds of 2-methoxybenzylidenepyruvate with some divalent metal ions

2010 ◽  
Vol 35 (1) ◽  
pp. 7-18
Author(s):  
M. Kobelnik ◽  
C. A. Ribeiro ◽  
D. S. Dias ◽  
G. A. Bernabé ◽  
M. S. Crespi
Keyword(s):  
Activation Energy ◽  
Solid State ◽  
Nitrogen Atmosphere ◽  
Divalent Metal ◽  
Point Of View ◽  
Conversion Degree ◽  
Divalent Metal Ions ◽  
Heating Rates ◽  
Exponential Factor ◽  
Kinetics Of

Divalent metal complexes of ligand 2-methoxybenzylidenepyruvate with Fe, Co, Ni, Cu and Zn as well as sodium salt were synthesized and investigated in the solid state. TG curves of these compounds were obtained with masses sample of 1 and 5mg under nitrogen atmosphere. Different heating rates were used to characterize and study these compounds from the kinetic point of view. The activation energy and pre-exponential factor were obtained applying the Wall-Flynn-Ozawa method to the TG curves. The obtained data were evaluated and the values of activation energy (Ea / kJ mol-1) was plotted in function of the conversion degree (α). The results show that due to mass sample, different activation energies were obtained. The results are discussed mainly taking into account the linear dependence between the activation energy and the pre exponential factor, where was verified the effect of kinetic compensation (KCE) and possible linear relations between the dehydrations steps of these compounds.

scholarly journals Physicochemical, Mineralogy, and Thermo-Kinetic Characterisation of Newly Discovered Nigerian Coals under Pyrolysis and Combustion Conditions

2020 ◽  
Author(s):  
Bemgba Bevan Nyakuma ◽  
Aliyu Jauro ◽  
Segun Ajayi Akinyemi ◽  
Hasan Mohd Faizal ◽  
Mohammed Baba Nasirudeen ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Energy Recovery ◽  
Major Elements ◽  
Industrial Applications ◽  
Physicochemical Analysis ◽  
Kinetic Properties ◽  
Exponential Factor ◽  
Minor Elements ◽  
Low Levels

Abstract In this study, the physicochemical, microstructural, mineralogical, thermal, and kinetic properties of three (3) newly discovered coals from Akunza (AKZ), Ome (OME), and Shiga (SHG) in Nigeria were examined for potential energy recovery. Physicochemical analysis revealed high combustible but low levels of polluting elements. The higher heating values (HHV) ranged from 18.65 MJ/kg (AKZ) to 26.59 MJ/kg (SHG). Microstructure and mineralogical analyses revealed particles with a rough texture, surfaces, and glassy lustre, which could be ascribed to metals, quartz, and kaolinite minerals. The major elements (C, O, Si, and Al), along with minor elements (Ca, Cu, Fe, K, Mg, S, and Ti) detected are associated with clays, salts, or the porphyrin constituents of coal. Thermal analysis showed mass loss (M L ) ranges from 30.51% – 87.57% and residual mass (R M ) from 12.44% – 69.49% under combustion (oxidative) and pyrolysis (non-oxidative) TGA conditions due to thermal degradation of organic matter, vitrinite, inertinite and liptinite macerals. Kinetic analysis revealed that the coal samples are highly reactive under the non-isothermal oxidative and non-oxidative conditions based on the Coats-Redfern Model. The activation energy ( E a ) ranged from 23.81 kJ/mol – 89.56 kJ/mol whereas the pre-exponential factor ( k o ) ranged from 6.77×10 -04 min -1 – 1.72×10 03 min -1 under pyrolysis and combustion conditions. In conclusion, the coals are practical feedstocks for either industrial applications or energy recovery.

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