scholarly journals Thermogravimetric study on the pyrolysis kinetic mechanism of waste biomass from fruit processing industry

2020 ◽  
Vol 24 (6 Part B) ◽  
pp. 4221-4239 ◽  
Author(s):  
Bojan Jankovic ◽  
Milos Radojevic ◽  
Martina Balac ◽  
Dragoslava Stojiljkovic ◽  
Nebojsa Manic
Keyword(s):  
Thermal Decomposition ◽  
Elevated Temperatures ◽  
Agricultural Waste ◽  
Kinetic Mechanism ◽  
Prunus Armeniaca ◽  
Differential Method ◽  
Waste Biomass ◽  
Heating Rates ◽  
Decomposition Reactions ◽  
Comparison Of The Results

The detailed kinetic analysis of slow pyrolysis process of apricot (Prunus armeniaca L.) kernal shells has been estimated, under non-isothermal conditions, through thermogravimetric analysis and derivative thermogravimetry. Thermal decomposition was implemented using four different heating rates (5, 10, 15, and 20?C per minute), with consideration of how this parameter effects on the process kinetics. The higher heating rates provoke the shift of thermoanalytical curves towards more elevated temperatures. Using isoconversional differential method, the variation of activation energy, Ea, with conversion fraction, ?, was detected, and pyrolysis reaction profile was discussed. After resolving the pyrolysis rate curves of individual biomass constituents, the temperature and conversion ranges of their thermal transformations were clearly identified. In the latter stage of analysis, every identified reaction step was considered through mechanistic description, which involves selection of the appropriate kinetic model function. The comparison of the results as well as discrepancies between them has been discussed. The corresponding rate-law equations related to thermal decomposition reactions of all biomass constituents present in the tested agricultural waste material have been identified.

Non-Isothermal Decomposition Kinetic of Polypropylene/Hydrotalcite Composite

2019 ◽  
Vol 19 (11) ◽  
pp. 7493-7501 ◽  
Author(s):  
Sheng Xu ◽  
Min Zhang ◽  
Siyu Li ◽  
Moyu Yi ◽  
Shigen Shen ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Nitrogen Atmosphere ◽  
Heating Rates ◽  
Decomposition Reactions ◽  
Kinetic And Thermodynamic Parameters ◽  
Málek Method ◽  
Boundary Reaction ◽  
Phase Boundary Reaction ◽  
Thermal Stability Of

P3O5-10 pillared Mg/Al hydrotalcite (HTs) as a functional fire-retarding filler was successfully prepared by impregnation-reconstruction, where the HTs was used to prepare polypropylene (PP) and HTs composite (PP/HTs). Thermal decomposition was crucial for correctly identifying the thermal behavior for the PP/HTs, and studied using thermogravimetry (TG) at different heating rates. Based on single TG curves and Málek method, as well as 41 mechanism functions, the thermal decompositions of the PP/HTs composite and PP in nitrogen atmosphere were studied under non-isothermal conditions. The mechanism functions of the thermal decomposition reactions for the PP/HTs composite and PP were separately “chemical reaction F3” and “phase boundary reaction R2,” which were also in good agreement with corresponding experimental data. It was found that the addition of the HTs increased the apparent activation energy Ea of the PP/HTs comparing to the PP, which improved the thermal stability of the polypropylene. A difference in the set of kinetic and thermodynamic parameters was also observed between the PP/HTs and PP, particularly with respect to lower ΔS≠ value assigned to higher thermal stability of the PP/HTs composite.

scholarly journals Kinetic Analysis of the Thermal Decomposition of Latex Foam according to Thermogravimetric Analysis

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Hongwei Fan ◽  
Yongliang Chen ◽  
Dongmei Huang ◽  
Guoqin Wang
Keyword(s):  
Thermal Decomposition ◽  
Thermogravimetric Analysis ◽  
Preexponential Factor ◽  
Kinetic Mechanism ◽  
Heating Rates ◽  
Third Order ◽  
Before And After ◽  
Ft Ir ◽  
The Mean ◽  
Nonisothermal Method

The thermal decomposition of latex foam was investigated under nonisothermal conditions. Pieces of commercial mattress samples were subjected to thermogravimetric analysis (TG) over a heating range from 5°C min−1 to 20°C min−1. The morphology of the latex foam before and after combustion was observed by scanning electron microscopy (SEM), and the primary chemical composition was investigated via infrared spectroscopy (FT-IR). The kinetic mechanism and relevant parameters were calculated. Results indicate that the decomposition of latex foam in the three major degradation phases is controlled by third-order reaction (F3) and by Zhuravlev’s diffusion equation (D5). The mean E values of each phase as calculated according to a single heating rate nonisothermal method are equal to 41.91 ± 0.06 kJ mol−1, 86.32 ± 1.04 kJ mol−1, and 19.53 ± 0.11 kJ mol−1, respectively. Correspondingly, the preexponential factors of each phase are equal to 300.39 s−1, 2355.65 s−1, and 27.90 s−1, respectively. The mean activation energy E and preexponential factor A of latex foam estimated according to multiple heating rates and a nonisothermal method are 92.82 kJ mol−1 and 1.12 × 10−3 s−1, respectively.

Synthesis and Thermal Characteristics of Complex Metal Hydride: NaAlH4

2003 ◽  
Vol 801 ◽  
Author(s):  
Bouziane Yebka ◽  
Gholam-Abbas Nazri
Keyword(s):  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Alkali Metals ◽  
Elevated Temperatures ◽  
Thermal Characteristics ◽  
Heating Rates ◽  
Complex Metal ◽  
Intermediate Phases ◽  
Initial Evolution ◽  
Decomposition Pathway

ABSTRACTComplex metal hydrides of general formula, ABH4 (A = alkali metals, B = third group elements such as B, Al, Ga) are potential candidates as hydrogen storage media for transportation. Thermal decomposition of complex hydrides generates hydrogen at elevated temperatures. The by -products of the dehydrogenation process can be regenerated using gaseous hydrogen at suitable temperature and pressure. The initial steps of thermal decomposition of NaAlH4 may be more complicated from the decomposition pathway reported in the literature. Close examination using thermal analysis by TGA, DSC and XRD measurements over the temperature range 30–500°C showed that the initial evolution of hydrogen occurred at a slow rate at ∼80°C, prior to fast decomposition at 190°C and at 260°C. Four regions of weight loss and five major endothermic peaks were measured during the thermal analysis. The effect of heating rate on the thermal analysis response showed that a high resolution of the thermal processes could be achieved at higher heating rates. Thermodynamic data was obtained for the various steps in the decomposition process including the formation of intermediate phases Na 3AlH6, and NaH. We also found that the decomposition of NaH is highly pressure dependent probably due to the high compressibility of the diffuse H− anion. The crystal-chemistry of NaAlH4 during decomposition has been established using X-ray diffraction analysis.

scholarly journals Thermal Decomposition Behavior and Thermal Safety of Nitrocellulose with Different Shape CuO and Al/CuO Nanothermites

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 725 ◽  
Author(s):  
Ergang Yao ◽  
Ningning Zhao ◽  
Zhao Qin ◽  
Haixia Ma ◽  
Haijian Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Bond Cleavage ◽  
Kinetic Mechanism ◽  
Thermal Safety ◽  
Ultrasonic Dispersion ◽  
Scanning Calorimetry ◽  
Decomposition Reactions ◽  
Al Nanoparticles ◽  
Decomposition Behavior

Bamboo leaf-like CuO(b) and flaky-shaped CuO(f) were prepared by the hydrothermal method, and then combined with Al nanoparticles to form Al/CuO(b) and Al/CuO(f) by the ultrasonic dispersion method. The phase, composition, morphology, and structure of the composites were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy scattering spectrometer (EDS). The compatibility of CuO, Al/CuO and nitrocellulose (NC) was evaluated by differential scanning calorimetry (DSC). The effects of CuO and Al/CuO on the thermal decomposition of NC were also studied. The results show that the thermal decomposition reactions of CuO-NC composite, Al/CuO-NC composite, and NC follow the same kinetic mechanism of Avrami-Erofeev equation. In the cases of CuO and Al/CuO, they could promote the O-NO2 bond cleavage and secondary autocatalytic reaction in condensed phase. The effects of these catalysts have some difference in modifying the thermolysis process of NC due to the microstructures of CuO and the addition of Al nanopowders. Furthermore, the presence of Al/CuO(f) can make the Al/CuO(f)-NC composite easier to ignite, whereas the composites have strong resistance to high temperature. Compatibility and thermal safety analysis showed that the Al/CuO had good compatibility with NC and it could be used safely. This contribution suggests that CuO and Al/CuO played key roles in accelerating the thermal decomposition of NC.

scholarly journals A DFT Analysis of Thermal Decomposition Reactions Important to Natural Products

2010 ◽  
Vol 5 (7) ◽  
pp. 1934578X1000500 ◽  
Author(s):  
William N. Setzer
Keyword(s):  
Thermal Decomposition ◽  
Density Functional ◽  
Elevated Temperatures ◽  
Aldol Reactions ◽  
Bornyl Acetate ◽  
Cope Rearrangement ◽  
Pericyclic Reactions ◽  
Ene Reactions ◽  
Decomposition Reactions ◽  
Electrocyclic Reactions

The thermal decomposition reactions of several important natural flavor and fragrance chemicals have been investigated using density functional theory (DFT, B3LYP/6-31G*). Retro-aldol reactions of glucose, fructose, hernandulcin, epihernandulcin, [3]-gingerol, and [4]-isogingerol; retro-carbonyl-ene reactions of isopulegol, lavandulol, isolyratol, and indicumenone; and pyrolytic syn elimination reactions of linalyl acetate, α-terpinyl acetate, and bornyl acetate, have been carried out. The calculations indicate activation enthalpies of around 30 kcal/mol for the retro-aldol reactions and for retro-carbonyl-ene reactions, comparable to pericyclic reactions such as the Cope rearrangement and electrocyclic reactions, and therefore important reactions at elevated temperatures (e.g., boiling aqueous solutions, gas-chromatograph injection ports). Activation enthalpies for pyrolytic eliminations are around 40 kcal/mol and are unlikely to occur during extraction or GC analysis.

scholarly journals Pyrolysis of agricultural waste biomass towards production of gas fuel and high-quality char: Experimental and numerical investigations

Fuel ◽  
2021 ◽  
Vol 296 ◽  
pp. 120611
Author(s):  
Agata Mlonka-Mędrala ◽  
Panagiotis Evangelopoulos ◽  
Małgorzata Sieradzka ◽  
Monika Zajemska ◽  
Aneta Magdziarz
Keyword(s):  
Agricultural Waste ◽  
Waste Biomass ◽  
High Quality ◽  
Numerical Investigations ◽  
Gas Fuel

Purification of dye-contaminated ethanol-water mixture using magnetic cellulose powders derived from agricultural waste biomass

2021 ◽  
Vol 258 ◽  
pp. 117690
Author(s):  
Sijie Zhou ◽  
Liangjun Xia ◽  
Zhuan Fu ◽  
Chunhua Zhang ◽  
Xiangyu Duan ◽  
...  
Keyword(s):  
Agricultural Waste ◽  
Water Mixture ◽  
Waste Biomass

scholarly journals Kinetic modelling for thermal decomposition of agricultural residues at different heating rates

2021 ◽  
Author(s):  
Hemant Kumar Balsora ◽  
S. Kartik ◽  
Thomas J. Rainey ◽  
Ali Abbas ◽  
Jyeshtharaj Bhalchandra Joshi ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Modelling ◽  
Agricultural Residues ◽  
Heating Rates

Global Reaction Model to Describe the Kinetics of Catalytic Pyrolysis of Coffee Grounds Waste

2017 ◽  
Vol 899 ◽  
pp. 173-178 ◽  
Author(s):  
Ronydes Batista Jr. ◽  
Bruna Sene Alves Araújo ◽  
Pedro Ivo Brandão e Melo Franco ◽  
Beatriz Cristina Silvério ◽  
Sandra Cristina Danta ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Large Scale ◽  
Catalytic Pyrolysis ◽  
Petroleum Products ◽  
Reaction Model ◽  
Heating Rates ◽  
Coffee Grounds ◽  
One Step ◽  
Global Reaction ◽  
The One

In view of the constant search for new sources of renewable energy, the particulate agro-industrial waste reuse emerges as an advantageous alternative. However, despite the advantages of using the biomass as an energy source, there is still strong resistance as the large-scale replacement of petroleum products due to the lack of scientifically proven efficient conversion technologies. In this context, the pyrolysis is presented as one of the most widely used thermal decomposition processes. The knowledge of aspects of chemical kinetics, thermodynamics these will, heat and mass transfer, are so important, since influence the quality of the product. This paper presents a kinetic study of slow pyrolysis of coffee grounds waste from dynamic thermogravimetric experiments (TG), using different powder catalysts. The primary thermal decomposition was described by the one-step reaction model, which considers a single global reaction. The kinetic parameters were estimated using nonlinear regression and the differential evolution method. The coffee ground waste was dried at 105°C for 24 hours. The sample in nature was analyzed at different heating rates, being 10, 15, 20, 30 and 50 K/min. In the catalytic pyrolysis, about 5% (w/w) of catalyst were added to the sample, at a heating rate of 30 K/min. The results show that the one-step model does not accurately represent the data of weight loss (TG) and its derivative (DTG), but can do an estimative of the activation energy reaction, and can show the differences caused by the catalysts. Although no one can say anything about the products formed with the addition of the catalyst, it would be necessary to micro-pyrolysis analysis, we can say the influence of the catalyst in the samples, based on the data obtained in thermogravimetric tests.

Sign in / Sign up

Export Citation Format

Share Document