scholarly journals Thermal Conversion of Pine Wood and Kinetic Analysis under Oxidative and Non-Oxidative Environments at Low Heating Rate

Proceedings ◽  
2020 ◽  
Vol 58 (1) ◽  
pp. 23
Author(s):  
Lelis Gonzaga Fraga ◽  
João Silva ◽  
Senhorinha Teixeira ◽  
Delfim Soares ◽  
Manuel Ferreira ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Mass Loss ◽  
Kinetic Analysis ◽  
Mass Loss Rate ◽  
Thermal Conversion ◽  
Inert Atmosphere ◽  
Thermochemical Conversion ◽  
Pine Wood ◽  
Oxidative Atmosphere ◽  
Conversion Stage

Atmosphere is one of the most significant factors in the thermal decomposition of biomass. In domestic or industrial biomass boilers, ambient oxygen concentration varies through time, which means that the reaction will change from pyrolysis to combustion. In this way, to analyze and compare each thermochemical conversion process, a simple analytical method, the non-isothermal thermogravimetric analysis, is carried out under oxidative (air) and non-oxidative (argon) environments at 10 °C/min and as a function of different flow rates (2 to 150 mL/min). Additionally, this work was complemented by a kinetic analysis considering a first-order reaction to each conversion stage and using the Coats–Redfern method. The effect of the atmosphere on the thermal decomposition behavior was evident. It was observed that the thermal decomposition of pine wood particles varied from three to two stages when the oxidative or inert atmosphere was applied. The presence of oxygen changes the mass loss curve mainly at high temperature, around 350 °C, where char reacts with oxygen. The maximum mass loss rate from experiments with the oxidative atmosphere is 15% higher than in an inert atmosphere, the average char combustion rate is approximately 5 times higher and the heat released reaches levels 3.44 times higher than in an inert atmosphere. Ignition and combustion indexes were also defined, and results revealed that particles are ignited faster under oxidative atmosphere and that, on average, the combustion index is 1.7 times higher, which reinforces the more vigorous way that the samples are burned and how char is burned out faster in the experiments with air. Regarding the kinetics analysis, higher activation energies, and consequently, lower reactivity was obtained under the oxidative atmosphere for the second stage (~125 kJ/mol) and under the inert atmosphere for the third thermal conversion stage (~190 kJ/mol).

scholarly journals Аналіз термодеструкції компонентів стовбура сосни звичайної в умовах Північного Степу України

2018 ◽  
pp. 39-44
Author(s):  
В. М. Ловинська ◽  
І. В. Рула
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Mass Loss ◽  
Scots Pine ◽  
Mass Loss Rate ◽  
Oxidative Degradation ◽  
Main Process ◽  
Exothermic Effect ◽  
Scanning Calorimetry ◽  
Pine Wood

Проведено дослідження процесу термодеструкції деревини і кори сосни звичайної в умовах північного байрачного Степу України. Методами термогравіметричного (TG), диференційно-термограві­метрич-ного (DTG) та диференційно-термічний (DTA) аналізів в окислювальному середовищі зі швидкістю нагріву 10 °С/хв здійснено якісний і кількісний аналіз та встановлено стадії термічного розкладання досліджуваних структурних компонентів стовбура. Отримано класичні криві, що описують процес термічного розкладання основних компонентів біомаси. Визначено основні температурні інтервали (етапів) процесів термоокислювальної деструкції. Розраховано енергію активації як в усьому досліджуваному діапазоні температур, так і для кожного із визначених етапів. Thermal decomposition of wood and bark from such coniferous species as Scots pine (Pinus sylvestris L.) within Northern Steppe of Ukraine has been studied using thermogravimetry (TG) and differential scanning calorimetry (DSC). Thermal qualitative and quantitative analysis of wood and bark samples was carried out in an oxidizing (air) atmosphere under conditions of a programmable heating up to 620 °C at heating rate 10 °C/min. The stages of thermal decomposition, the temperature intervals, the mass loss, the mass loss rate, the temperature peaks were determined for investigated species. The kinetic thermal degradation parameters of wood and bark were obtained by the Broido method. Scots pine wood and bark was characterized from the data of activation energy analysis at various stages of thermal decomposition. It is shown that the thermal decomposition process of pine wood and bark biomass is characterized by the behavior of the three main components of lignocellulosic biomass: hemo-cellulose, cellulose, and lignin. Four temperature ranges is identified, which characterize the basic stages of thermal decomposition of samples. The main process of thermo-oxidative degradation of cellulose in the bark began at a temperature ~ 220 °С, while for the wood – at ~ 240 °С. Less exothermic effect is observed for the bark at lower temperatures. There are two peaks on differential thermogravimetric curves of Scots pine wood and bark. The first was at a maximum at 320 °C for wood and 300 °C for bark, the second is at 440 °C for bark and 490 °C for wood, which correlates with the burning of coal. It was established that the activation energy values, that corresponding to the destruction process of the Scots pine trunk phytomass components in the studied temperature range were almost unchanged for wood and bark. But each of the destruction stages is characterized by different activation energy, which is well demonstrated by the peaks of differential thermogravimetric curves.

scholarly journals Flammability and Thermal Kinetic Analysis of UiO-66-Based PMMA Polymer Composites

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4113
Author(s):  
Ruiqing Shen ◽  
Tian-Hao Yan ◽  
Rong Ma ◽  
Elizabeth Joseph ◽  
Yufeng Quan ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Mass Loss ◽  
Polymer Composites ◽  
Flame Retardants ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Protective Layer ◽  
Average Mass ◽  
Microscale Combustion Calorimeter ◽  
Combustion Calorimeter

Metal–organic frameworks (MOFs) are emerging as novel flame retardants for polymers, which, typically, can improve their thermal stability and flame retardancy. However, there is a lack of specific studies on the thermal decomposition kinetics of MOF-based polymer composites, although it is known that they are important for the modeling of flaming ignition, burning, and flame spread over them. The thermal decomposition mechanisms of poly (methyl methacrylate) (PMMA) have been well investigated, which makes PMMA an ideal polymer to evaluate how fillers affect its decomposition process and kinetics. Thus, in this study, UiO-66, a common type of MOF, was embedded into PMMA to form a composite. Based on the results from the microscale combustion calorimeter, the values of the apparent activation energy of PMMA/UiO-66 composites were calculated and compared against those of neat PMMA. Furthermore, under cone calorimeter tests, UiO-66, at only 1.5 wt%, can reduce the maximum burning intensity and average mass loss rate of PMMA by 14.3% and 12.4%, respectively. By combining UiO-66 and SiO2 to form a composite, it can contribute to forming a more compact protective layer, which shows a synergistic effect on reducing the maximum burning intensity and average mass loss rate of PMMA by 22.0% and 14.7%, respectively.

scholarly journals Influence of Operating Conditions on the Thermal Behavior and Kinetics of Pine Wood Particles Using Thermogravimetric Analysis

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2756 ◽  
Author(s):  
Lelis Gonzaga Fraga ◽  
João Silva ◽  
Senhorinha Teixeira ◽  
Delfim Soares ◽  
Manuel Ferreira ◽  
...  
Keyword(s):  
Thermogravimetric Analysis ◽  
Mass Loss ◽  
Heating Rate ◽  
Mass Loss Rate ◽  
Air Flow ◽  
Operating Conditions ◽  
Flow Rates ◽  
Pine Wood ◽  
The Third ◽  
Third Stage

Although there are many studies available in literature about biomass pyrolysis or devolatilization using thermogravimetric analysis (TGA), the effects of important operating parameters have infrequently been investigated for pine wood particle combustion. Consequently, the present study investigates the influence of particle size (63 µm to 1 mm), heating rate (5 to 243 °C/min), and air flow rate (10 to 150 mL/min) on the mass loss of pine wood using TGA. Additionally, the kinetic parameters considering the different conditions were determined to be incorporated in a numerical model. The effect of the heating rate on the thermal decomposition behavior has shown that the thermogravimetric and derivative thermogravimetric curves were shifted to higher temperatures with the increase in the heating rate. In this way, the heating rate affects the temperature at which the highest mass loss rate occurs as well as its value. Furthermore, comparing the higher and lower heating rate, the time to complete the combustion and the release are around 22 times higher when a higher heating rate is applied. On the other hand, the effects of four different air flow rates were compared and similar results were obtained. Regarding the kinetic analysis, it was verified at various heating and air flow rates with different particle sizes that the highest activation energy was mostly obtained during char combustion (~131–229 kJ/mol). Furthermore, in the second stage higher heating rates had the highest reactivity, and in the third stage there were not too many changes. In terms of the effect of air flow rates, a maximum variation of 15 kJ/mol was obtained in the third stage and, therefore, no significant effect on the reactivity for all particles was found.

Thermogravimetric Analysis and Characterisation of Yard Waste as a Feedstock to Gasification Process

2013 ◽  
Author(s):  
Anjireddy Bhavanam ◽  
R. C. Sastry
Keyword(s):  
Thermo Gravimetric Analysis ◽  
Thermal Conversion ◽  
Inert Atmosphere ◽  
Thermochemical Conversion ◽  
Gravimetric Analysis ◽  
Heating Rates ◽  
Thermo Gravimetric ◽  
Yard Waste ◽  
Gasification Process ◽  
Institute Of Technology

Gasification has great potential to make use of the biomass and wastes as a source for energy among various thermochemical conversion processes. The aim of this work is to study the suitability of yard waste for energy conversion using gasification process by Thermo gravimetric analysis. Yard waste (consisting of leaves, twigs and grass clippings) is collected from the National Institute of Technology Warangal. It is then dried and ground to a particle size of less than 250μm for thermo gravimetric study. Before going to thermo gravimetric analysis; the sample is analyzed to measure the main properties that affect thermal conversion. Moisture content present in the sample is determined by the oven drying method. Proximate is done according to standard ASTM test methods and ultimate analysis is conducted using elemental analyzer. Finally thermo gravimetric analyses is performed at various heating rates of 10, 30, and 50°Cmin−1 in nitrogen (inert) and air (oxidizing) atmospheres. The weight losses of yard waste in inert atmosphere occur in three stages and in air it occurs in four stages.

Kinetic Analysis of Thermal Decomposition of Epoxy Resin/Polyaniline Nanocomposites

2011 ◽  
Vol 213 ◽  
pp. 502-505 ◽  
Author(s):  
Shao Yun Shan ◽  
Qing Ming Jia ◽  
Li Hong Jiang ◽  
Ya Ming Wang
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Analysis ◽  
Epoxy Resin ◽  
Inert Atmosphere ◽  
Pani Nanofibers ◽  
Thermal Degradation Behavior ◽  
Isoconversional Analysis ◽  
Fwo Method ◽  
Thermal Stability Of

Polyaniline(PANI) nanofibers were firstly prepared by rapid mixture method, EP/PANI nanocomposite was obtained by in-situ adding the PANI nanofibers to epoxy resin(EP). Thermal degradation behavior of PANI and kinetic analysis of thermal decomposition of EP/PANI nanocomposites were investigated in detail by using thermogravimetric analyser (TGA) in inert atmosphere. Typical three step decomposition profiles of PANI were obtained. On the basis of isoconversional analysis by the methods of Kissinger-Akahira-Sunose method(KAS method) and Flynn-Wall-Ozawa method(FWO method), it was found that the value of the activation energy of EP/PANI nanocomposites is higher than that of pure EP, which proves that PANI nanofibers obviously improve the thermal stability of pure EP.

The Kinetic Analysis of Thermal Decomposition of PMMA/MMT Nanocomposites

2007 ◽  
Vol 353-358 ◽  
pp. 1366-1369 ◽  
Author(s):  
Kui Chen ◽  
Rui Chen Yang ◽  
S.W. Cheng
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermal Decomposition ◽  
Methyl Methacrylate ◽  
Mass Loss ◽  
Apparent Activation Energy ◽  
Kinetic Analysis ◽  
Decomposition Kinetics ◽  
Ozawa Equation ◽  
Thermal Stability Of

The thermal decomposition kinetics and thermal stability of poly (methyl methacrylate) (PMMA) and PMMA/ montmorillonite (MMT) nanocomposites containing 4 wt% MMT were researched by thermogravimetry (TG). The results show that, because of the barrier behavior of exfoliated MMT layer, the temperature of thermal decomposition of PMMA/ MMT nanocomposites is improved by about 10 °C, and thermal stability is improved by about double. The apparent activation energy of decomposition, calculated by Ozawa equation, of nanocomposites is higher than that of PMMA before 27 % mass loss.

scholarly journals PHYSICO-CHEMICAL PARAMETERS OF SIBERIAN LARCH (LARIX SIBIRICA) BARK EXTRACTED WITH WATER-AMINO-ALCOHOLIC EXTRACTANTS

2021 ◽  
pp. 103-107
Author(s):  
Elena Alexandrovna Petrunina ◽  
OlgaOlga Aleksandrovna Shapchenkova ◽  
SergeySergey Redzhinaldovich Loskutov
Keyword(s):  
Thermal Decomposition ◽  
Mass Loss ◽  
Mass Loss Rate ◽  
Siberian Larch ◽  
Larix Sibirica ◽  
Conversion Degree ◽  
Wood Pellets ◽  
Scanning Calorimetry ◽  
Air Atmosphere ◽  
Thermogravimetric Data

This paper presents the results of a thermal analysis, that involved thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC), of natural bark of Siberian larch (Larix sibirica Ldb.) vs. the bark extracted with 5% water-monoethanolamine (MEA) and (vs.) 5% water-triethanolamine (TEA). Thermogravimetric data obtained in an oxidative (air) atmosphere allowed us to identify temperature ranges of thermal decomposition stages for the larch bark samples, as well as to determine the corresponding mass loss and mass loss rate at programmed heating. The Ozawa-Flynn-Wall (OFW) method was used to calculate the dependence of activation energy of the thermal decomposition of experimental samples on the conversion degree (Еа = f(a)); the symbate run of Еа = f(a) curves was established. The DSC data obtained agreed with those of TG/DTG. The integral heat of the bark thermal decomposition (9.60 kJ/g and 14.12 kJ/g for MEA and TEA, respectively) indicated the bark to be competitive with other biofuels, such as briquetted lignin, wood pellets, sunflower husk, rapeseeds, and straw.

scholarly journals Thermogravimetric and Kinetic Analysis of High-Temperature Thermal Conversion of Pine Wood Sawdust under CO2/Ar

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5328
Author(s):  
Bao Wang ◽  
Yujie Li ◽  
Jianan Zhou ◽  
Yi Wang ◽  
Xun Tao ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Room Temperature ◽  
Thermal Conversion ◽  
Heating Rates ◽  
Pine Wood ◽  
Master Plot ◽  
Char Gasification ◽  
Wood Sawdust ◽  
Pine Wood Sawdust ◽  
Kinetics Of

The gasification behavior of pine wood sawdust was investigated in CO2 with different heating rates of 5, 10, 15, and 20 °C/min from room temperature to 1400 °C by thermogravimetric analysis (TGA) and mass spectrometry (MS). It was also examined under Ar to compare the differences observed under CO2 at heating rate of 10 °C/min. Kinetics of pine wood sawdust thermal decomposition was determined by the models of FWO, KAS and master plot method. TGA results revealed different reaction sections from pyrolysis to char gasification under CO2. The pyrolysis behavior was similar under CO2 and Ar and had a similar energy required value about 590 kJ/kg from 250 °C to 420 °C. CO, CH4, and H2 were the primary gases obtained from thermal decomposition, and the amounts of which in CO2 atmosphere were higher than those obtained in Ar. The average activation energy for pyrolysis under CO2 was 184.72 kJ/mol.

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