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.

Thermal Decomposition Kinetics of RDX with Distributed Activation Energy Model

2013 ◽  
Vol 641-642 ◽  
pp. 144-147 ◽  
Author(s):  
Ming Hua Chen ◽  
Tao Zhang ◽  
Wen Ping Chang ◽  
Xiao Biao Jia
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Energy Model ◽  
Decomposition Kinetics ◽  
Thermal Decomposition Kinetics ◽  
Distributed Activation Energy Model ◽  
Thermogravimetric Analyzer ◽  
Decomposition Stage ◽  
Decomposition Processes ◽  
Kinetics Of

The thermal decomposition kinetics of RDX at different rates was studied by thermogravimetric analyzer(TG) and the activation energy of RDX was calculated by distributed activation energy model. It is shown that the thermal decomposition processes of RDX were divided into three stages according to the TG curves, they are molten stage, thermal decomposition stage and eng stage. The activation energies of RDX are all between 124.34 and 181.48KJ•mol-1 in the thermal decomposition stage of non-monotonously increasing. The activation energy of RDX is 139.98 KJ•mol-1 in the molten stage, and the thermal decomposition stage is167.24KJ•mol-1.

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 Parametric Study of NTH Order Distributed Activation Energy Model for Isothermal Pyrolysis of Forest Waste Using Gaussian Distribution

2017 ◽  
Vol 20 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Alok Dhaundiyal ◽  
Suraj B. Singh
Keyword(s):  
Activation Energy ◽  
Gaussian Distribution ◽  
Frequency Factor ◽  
Energy Model ◽  
Distributed Activation Energy Model ◽  
Cedrus Deodara ◽  
Upper Limit ◽  
Forest Waste ◽  
Thermoanalytical Data ◽  
Distribution Frequency

Abstract This paper deals with the influence of some factors relevant to isothermal pyrolysis of residual leaves of Cedrus deodara on the asymptotic solution of the non-isothermal nth order distributed activation energy model (DAEM) using Gaussian distribution. Frequency factor, integral upper limit, the reaction order and the variance of Gaussian distribution are the parameters taken under purview of this study. In order to determine the kinetic parameters of the isothermal nth order Gaussian DAEM from thermoanalytical data of loose biomass pyrolysis, the variation of these factors has been considered. The obtained results show that the predicted results for nth order DAEM hold good at upper limit of dE, E∞ = 39 kJ mol-1.

scholarly journals Thermogravimetric and Kinetic Analysis of Melon (Citrullus colocynthis L.) Seed Husk Using the Distributed Activation Energy Model

2015 ◽  
Vol 15 (1) ◽  
pp. 77-89 ◽  
Author(s):  
Bemgba Bevan Nyakuma
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Kinetic Analysis ◽  
Biomass Conversion ◽  
Clean Energy ◽  
Frequency Factor ◽  
Energy Model ◽  
Distributed Activation Energy Model ◽  
Solid Biofuel ◽  
Seed Husk

Abstract This study seeks to characterize the thermochemical fuel properties of melon seed husk (MSH) as a potential biomass feedstock for clean energy and power generation. It examined the ultimate analysis, proximate analysis, FTIR spectroscopy and thermal decomposition of MSH. Thermogravimetric (TG) analysis was examined at 5, 10, 20 °C/min from 30-800 °C under nitrogen atmosphere. Subsequently, the Distributed Activation Energy Model (DAEM) was applied to determine the activation energy, E, and frequency factor, A. The results revealed that thermal decomposition of MSH occurs in three (3) stages; drying (30-150 °C), devolatization (150-400 °C) and char degradation (400-800 °C). Kinetic analysis revealed that the E values fluctuated from 145.44-300 kJ/mol (Average E = 193 kJ/mol) while A ranged from 2.64 × 1010 to 9.18 × 1020 min-1 (Average E = 9.18 × 1019 min-1) highlighting the complexity of MSH pyrolysis. The fuel characterization and kinetics of MSH showed it is an environmentally friendly solid biofuel for future thermal biomass conversion.

scholarly journals Distributed Activation Energy Modelling Using a Parabolic Heating Profile

2021 ◽  
Vol 24 (1) ◽  
pp. 27-34
Author(s):  
Alok Dhaundiyal ◽  
Suraj B. Singh
Keyword(s):  
Activation Energy ◽  
Frequency Factor ◽  
Energy Model ◽  
Distributed Activation Energy Model ◽  
Linear Temperature ◽  
First Order ◽  
Forest Waste ◽  
Energy Modelling ◽  
Pyrolysis Reactor ◽  
Heating Profile

AbstractThis work investigates the thermal decomposition of forest waste for a non-linear temperature distribution inside the pyrolysis reactor. Quantitative analysis of the distributed activation energy model is explained graphically. It has been assumed that thermal profile varies according to the general parabolic equation with the initial condition (0, T0). The approximated solution of the non-analytical integral is determined by the Laplace integral method. The integral limit for the distributed activation energy model (DAEM) is found to vary from 211 to 810 kJ·mol−1; whereas the frequency factor (the first-order reactions) for the corresponding range of the activation energy lies in the domain of 400–2000 min−1. The acceleration in the char formation has been found for the reactions other than that of the first order.

scholarly journals Modeling of Isocyanate Synthesis by the Thermal Decomposition of Carbamates

Computation ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 89
Author(s):  
Ratmir Dashkin ◽  
Georgii Kolesnikov ◽  
Pavel Tsygankov ◽  
Igor Lebedev ◽  
Artem Lebedev ◽  
...  
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Mathematical Model ◽  
Thermal Decomposition ◽  
Computer Models ◽  
Computational Experiments ◽  
Comsol Multiphysics ◽  
Suggested Model ◽  
Exponential Factor ◽  
Calculation Results

The presented work is devoted to isocyanate synthesis by the thermal decomposition of carbamates model. The work describes the existing isocyanate-obtaining processes and the main problems in the study of isocyanate synthesis by the thermal decomposition of carbamates, which can be solved using mathematical and computer models. Experiments with carbamates of various structures were carried out. After processing the experimental data, the activation energy and the pre-exponential factor for isocyanate synthesis by the thermal decomposition of carbamates were determined. Then, a mathematical model of the reactor for the thermal decomposition of carbamates using the COMSOL Multiphysics software was developed. For this model, computational experiments under different conditions were carried out. It was shown that the calculation results correspond to the experimental ones, so the suggested model can be used in the design of the equipment for isocyanate synthesis by the thermal decomposition of carbamates.

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