Thermogravimetric Analysis Experiments Research Articles

COMPARATIVE STUDY OF VARIOUS APPROACHES IN ANALYSIS OF TGA DATA OF DEVOLATILIZATION OF HIGH ASH INDIAN COAL

ABSTRACT Thermo gravimetric analysis (TGA) has been regularly employed for the estimation of devolatilization rates and measurement of char reactivity of coal. In general, TGA studies may be classified as isothermal or non-isothermal. In the first case temperature of the sample is kept constant whereas in case of latter the rate of temperature increase is kept constant. The current research work deals with the non-isothermal TGA study and kinetic analysis of three typical pulverized high-ash Indian coal samples each weighing around 15 mg. TGA experiments were carried out for four different heating rates (5, 10, 15, 20 K/min) and weight loss curves have been obtained. Out of the various methods proposed to analyze the TGA data, the following methods have been evaluated i) Friedman method, ii) Flynn-Wall-Ozawa method (FWO), iii) Kissinger method, iv) Kissinger-Akahira-Sunose (KAS) method, and v) Miura-Maki method. Activation energy and frequency factor to be used in the Arrhenius equation is calculated using all the above methods. The most accurate method for analyzing TGA data for high-ash Indian coal is FWO as per studies carried out in this research work.

Experimental study on thermal effect and gas release laws of coal-polyurethane cooperative spontaneous combustion

This paper presents a research on the kinetics and gas release laws of the cooperative spontaneous combustion of coal-polyurethane binary system by means of thermogravimetric analysis and spontaneous combustion simulation experiments. The coal-polyurethane binary system is more prone than individual samples to combustion. The polyurethane mass fraction has a great influence on the cooperative spontaneous combustion process. As the polyurethane mass fraction rises, the activation energies of oxygen absorption stage and pyrolysis stage decrease. The combustion residues of coal-polyurethane binary system scorches into lumps and the surfaces of the particles become rougher. During spontaneous combustion, the initial release temperatures of the four gases CO2, CO, C2H6 and C2H4 drop as the polyurethane mass fraction increases. The gas release amount of them increases with increasing polyurethane mass fraction. And the amount of CH4 decreases as the polyurethane mass fraction increases. The CO/CO2 ratio with temperature for different polyurethane mass fraction have the same trends. The results of this study have implications concerning polyurethane materials application and fire protection in coal mine.

Experimental taphonomy of fish bone from warm and cold water species: Testing the effects of amino acid composition on collagen breakdown in modern fish bone using thermal maturation experiments

Decay experiments have the potential to provide useful analogues in the interpretation of archaeological remains. Previous studies have focused on how physical properties or processing methods can influence fish bone distributions within archaeological sites. However, the means by which intrinsic chemical properties of fish bone, such as baseline collagen type I [‘collagen (I)’] chemistry, may affect both biomolecule and whole bone degradation has not been the focus of any prior study. The variation of facies and resulting impact on taphonomy is not a new concept, but an understanding of the discrete relationship between temperature and the breakdown of collagen (I) in bone material has not been well explored. Here, modern fish bone powder is subjected to differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and water-immersed heat experiments. This is to test whether taxa with less thermally stable collagen (I) configurations, such as cold-water species with reduced proline and hydroxyproline concentrations (Pro+Hyp), will generate collagen breakdown products (TOC and TN) more rapidly than those with more thermally stable arrangements, such as warm-water fish with typically increased Pro+Hyp. Our results show that bone collagen (I) in the cold-water fish species in this study (cod and herring with lower Pro+Hyp concentrations) display significantly increased decomposition rates than collagen (I) from the warm-water fishes in this study (amberjack and tilapia with higher Pro+Hyp concentrations), given the same experimental conditions (heating in water at 75 °C for up to eight days). Initial reaction rate estimates, based on TOC and TN product concentrations, suggest that cod bone (15.6% Pro+Hyp) reacts ~9 times faster than tilapia bone (20.3% Pro+Hyp). We suggest that the primary influencer of collagen (I) stability in bone is the concentration of Pro+Hyp residues and not a function of physical bone structure. Our results suggest that a reduction in collagen (I) stability is likely to lead to a decrease in whole bone stability following deposition, due to the intimate association between organic and inorganic phases of bone. Therefore, species composition based upon bone remains may vary in archaeological and palaeontological sites, as a function of the thermal stability of collagen (I).

Evaluating the oxidation kinetic parameters of gasoline direct injection soot from thermogravimetric analysis experiments

The abatement of particulate matter in gasoline direct injection (GDI) engines requires the use of particulate filters. In turn, the optimisation of their regeneration is based on a deep knowledge of the soot oxidation behaviour. The determination of the intrinsic kinetic parameters of GDI soot is explored based on thermogravimetric analysis (TGA) and reaction rate modelling. New understanding on the oxidation of GDI soot is provided enabling an accurate prediction in a wide range of temperature and O2 concentration. Firstly, the dependence of the soot reaction order on the boundary conditions is discussed. The analysis of the Arrhenius equation parameters reveals variable O2 reaction order. It leads to consider the effect of mass transfer and adsorption (Langmuir and Dubinin-Radushkevich isotherms) as reaction rate limiters. Combined with the soot reaction order approach, the prediction ability of the proposed model is assessed in an extended range of isothermal and non-isothermal TGA experiments.

Light-Responsive Proton Conductor: Record High Gain of Proton Conductivity Achieved by Photoinduced Electron-Transfer Strategy

Light-Responsive Proton Conductor: Record High Gain of Proton Conductivity Achieved by Photoinduced Electron-Transfer Strategy

Catalytic effect of solvothermally prepared Cu2(bdc)2(bpy) metal-organic framework on thermal decomposition of ammonium perchlorate

Cu2(bdc)2 (bpy) metal-organic framework (MOF) was prepared by solvothermal method and the structure was characterized by powder X-ray diffraction (PXRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR). The specific surface area and the pore size distributions was estimated by Brunauer–Emmett–Teller (BET) method and micropore (MP) plot. This metal-organic framework was used as catalyst to improve the thermal decomposition of ammonium perchlorate (AP) and thermal behaviors of the mixed samples containing the catalyst and ammonium perchlorate were investigated by thermogravimetric analysis (TGA) and differential scanning calorimetric (DSC) experiments. The results showed that in the catalyzed samples, the heat released from thermal decomposition of ammonium perchlorate is much higher (more than 3 times in sample containing 4% by weight of the metal-organic framework as catalyst) and thermal decomposition temperature was significantly lower than that of pure AP (about 110 ​°C decrease in sample containing 2% by weight of catalyst). Thermal decomposition temperature range of AP was reduced from 178 ​°C to 105 ​°C and 61 ​°C in the samples containing 4% and 2% by weight of catalyst respectively. The results of kinetic calculations obtained from Kissinger method showed effective catalytic performance of this metal-organic framework by increasing the thermal decomposition rate constant of AP more than 1.8 times at a much lower temperature.

Simultaneous pretreatment and catalytic conversion of polyolefins into hydrocarbon fuels over acidic zeolite catalysts

The effect of pre-degradation treatment in catalytic pyrolysis of polymer was assessed using thermogravimetric analysis (TGA) and pyrolysis reactor experiments of different polymers on various catalysts. Intimate contact between the polymer and catalyst was achieved using physical, mechanical and thermal treatments. The results from the TGA analysis show that pre-degradation treatment has greatly improved the performance of the catalyst attaining maximum degradation at lower temperature. Pre-degradation treatment had increased the liquid yield and lowered the coke yield at various extents depending on the catalyst structure and acidity. The ZSM-5 catalyst with high Si/Al ratio showed maximum amount of (C5–C9) and ZSM-5 with lower Si/Al ratio has maximum percentage of (C14–C20). Based on the performance of the pre-degradation treatment methods, normal mixing produced the maximum amount of lighter fractions and therefore pre-degradation treatment can serve to enhance the gasoline fraction while the diesel fraction can be optimised using the co-pressing method, where polymer and catalyst particles were thoroughly mixed and co-pressed together into mixed particles. Coke characterisation showed coke formed by linear low density polyethylene contained more volatile coke components while polypropylene coke had higher percentage of hard coke. ZSM-5 had lower retention of coke components with volatile coke precursors. The volatility of the coke increases while coke concentration and decreases as the catalyst amount decreases. Pre-degradation treatment facilitated the formation of soft coke components that are easy to remove in inert atmosphere.

The relevance of thermal effects during CO2 adsorption and regeneration in a geopolymer-zeolite composite: Experimental and modelling insights

Low temperature adsorption of carbon dioxide in solid materials is a cost-effective option for implementing decarbonization in a retrofitting plant strategy. Among several natural and artificial sorbents, geopolymer-zeolite composites represent a valid alternative owing to the affinity and synergy between zeolite and the geopolymer binder. Thermal effects are usually associated to CO2 adsorption in solids: in particular zeolites exhibit values in the range 33 to 40 kJ/mol. The occurrence of the thermal effects (i.e. positive/negative variation of the bed temperature) impacts on the adsorption/desorption behavior and system performance. In this study, the relationship between adsorption/desorption and bed temperature has been studied in dynamic tests, complemented by thermogravimetric analysis and static sorption experiments. In dynamic tests, the maximum adsorption capacity was 1.40 mmol/g at 20% mol. of CO2 inlet concentration, whilst it resulted 0.80 mmol/g in a shorter breakthrough test. Correspondingly, the temperature peak during adsorption revealed an increase up to 20 °C. The thermal effect was exploited during desorption with a combined pressure-swing and temperature-swing strategy, leading to a shorter time for sorbent regeneration. A novel numerical model of the adsorption process well fitted the experimental results at different inlet CO2 concentration, providing insights for process design and optimization.

Synthesis of a New Flame Retardant Curing Agent with Phosphorus and Their Application to Epoxy Resins

The synthesis has been made on a new kind of phosphorus-containing compound 2-(phenylphosphoryl)-1,4-benzenediol, which is defined as PPBDO. Besides, it is utilized as a flame retardant and meanwhile a curing agent of epoxy resins (EP). The description of the chemical structure was made in virtue of Fourier transform infrared (FTIR) spectroscopy, 1H, together with 13C nuclear magnetic resonance. Investigation on the flame retardant properties, cured epoxy resins’ combusting performances, and thermal degradation behaviors in virtue of restricting oxygen index (LOI) and vertical burning tests (UL-94) as well as cone calorimeter and thermogravimetric analysis (TGA) experiments. According to the results from the cone tests, the PPBDO integration could efficiently decreased the combustion parameters featured by epoxy resins thermosets, including Heat release rate (HRR), Total heat release (THR), etc.. The TGA results displayed the PPBDO introduction managed to enhance epoxy resins matrix under the decomposition in advance, in comparison to the one pure EP, thus giving rise to a more concentration of char yield as well as thermal stability on the condition of high temperature.

Characterisation of pyrolysis kinetics and detailed gas species formations of engineering polymers via reactive molecular dynamics (ReaxFF)

One of the major limiting factors in fire modelling involving solid pyrolysis of polymer materials is the fundamental understanding of thermal degradation process from solid fuel to gas volatiles. This also brings along other challenges such as the characterisation of the parent combustion fuel in the gas-phase chemical reaction process. To bridge the knowledge gap, this article proposes a methodology applying molecular dynamics (MD) simulation as a tool to characterise the thermal degradation process of polymer composites, especially the emission of volatile and toxic gas species. The method was applied to three common engineering polymers: i) high-density polyethene (HDPE), ii) polymethyl methacrylate (PMMA), and iii) high-impact polystyrene (HIPS). Based on the modelling results, the chemical distribution of the fully-decomposed chemical compounds was realised for the selected polymers. The chemical composition and charring kinetics were validated against thermogravimetry data via experimental measurement. Numerical simulations demonstrated good agreement with the thermogravimetric analysis experiments. It was found that all HDPE, PMMA, and HIPS formed fuel gas with alkane group (i.e. mainly C1-C3) that acted as the combustible source. Furthermore, the composition of char formations for the selective polymers can be predicted by the MD simulation through analysing the accumulation of pure carbon chain compounds. In this study, MD simulation identified the detailed decomposition process from solid to gas phases, which could further act as the precursors of combustible fuel gases in combustion models, and significantly enhance the reliability of toxic gas, charring, and smoke particulate predictions.

Mechanical and thermal properties of PMMA resin composites for interim fixed prostheses reinforced with calcium β-pyrophosphate

Interim restorations are essential in fixed prosthodontics as they provide temporary protection of teeth before the insertion of the permanent restoration. Poly(methyl methacrylate) (PMMA) is widely used in the fabrication of interim-fixed restorations as it is a biocompatible material with a lot of convenient properties. However, it exhibits low impact and tensile strength and therefore it is necessary to be reinforced. Calcium β-pyrophosphate (β-CPP) is considered a promising reinforcing material for dental applications, especially for enamel regeneration due to its stability at low pH and its low wear rate. The aim of this study was to manufacture PMMA/β-CPP composites suitable for fixed-interim restorations and to study their mechanical and thermal properties. In order to enhance β-CPP dispersion into PMMA matrix, ball-milling was performed for 1 or 6 h. Three-point bending test was performed to study flexural strength, Dynamic Mechanical Analysis (DMA) to reveal the elastic and viscous moduli along with Tg, Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction Analysis (XRD) to investigate the structure of the materials and SEM for the morphological evaluation of both composite powders and polymerized specimens. Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) experiments were performed to study their thermal properties. A statistically significant increase in flexural strength was found in the 0.5, 0.75 and 1% composite groups after 6 h ball-milling, relative to the control, with the 6 h ball milling mixed specimens, presenting the highest flexural strength values. The brittle fracture type was common to all groups. An obvious improvement of the mechanical properties and a slight improvement in the thermal stability of the composite materials values were also observed as β-CPP content was increased, while Tg values were statistically not-affected.

Effect of cycle-induced crack formation on the hydration behaviour of K2CO3 particles: Experiments and modelling

Thermochemical energy storage using salt hydrates is a promising concept to bridge the gap between supply and demand for solar thermal energy in residential buildings. Using a suitable thermochemical material such as a salt hydrate, a thermal energy storage device, also known as a heat battery, can be created to supply low-temperature thermal energy during colder periods. To generate adequate power from a heat battery for the production of domestic hot tap water or space heating, the hydration rate of the salt hydrate needs to be sufficiently fast. It is hypothesized that the hydration rate of the material increases over multiple charge and discharge cycles due to crack formation and volume increase of the salt hydrate particles. This hypothesis is tested by performing two kinds of experiments: optical microscopy experiments using a micro-climate chamber to evaluate the particle size, and Thermo Gravimetric Analysis (TGA) experiments to determine the hydration rate of the particles. The hydration rate and particle size are input for a nucleation and growth model that takes into account crack formation and particle growth. Optical microscopy experiments show a particle expansion of approximately 30 % over 12 cycles. Typical hydration rates are increased by a factor 15 comparing the first and the 12th TGA cycle. It is shown that particle growth and crack formation significantly contribute to the improvement of the hydration rate. Finally, taking into account crack formation and particle growth in the numerical model results in a good agreement between model and experiments. Such a numerical model can be used for heat battery design.

Characterisation and composition identification of waste-derived fuels obtained from municipal solid waste using thermogravimetry: A review.

Thermogravimetric analysis (TGA) is the most widespread thermal analytical technique applied to waste materials. By way of critical review, we establish a theoretical framework for the use of TGA under non-isothermal conditions for compositional analysis of waste-derived fuels from municipal solid waste (MSW) (solid recovered fuel (SRF), or refuse-derived fuel (RDF)). Thermal behaviour of SRF/RDF is described as a complex mixture of several components at multiple levels (including an assembly of prevalent waste items, materials, and chemical compounds); and, operating conditions applied to TGA experiments of SRF/RDF are summarised. SRF/RDF mainly contains cellulose, hemicellulose, lignin, polyethylene, polypropylene, and polyethylene terephthalate. Polyvinyl chloride is also used in simulated samples, for its high chlorine content. We discuss the main limitations for TGA-based compositional analysis of SRF/RDF, due to inherently heterogeneous composition of MSW at multiple levels, overlapping degradation areas, and potential interaction effects among waste components and cross-contamination. Optimal generic TGA settings are highlighted (inert atmosphere and low heating rate (⩽10°C), sufficient temperature range for material degradation (⩾750°C), and representative amount of test portion). There is high potential to develop TGA-based composition identification and wider quality assurance and control methods using advanced thermo-analytical techniques (e.g. TGA with evolved gas analysis), coupled with statistical data analytics.

Crystal structures of the anhydrous and two solvated forms of methyl 4-(4-fluorophenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate.

Methyl 4-(4-fluorophenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate, (I), was found to exhibit solvatomorphism. The compound was prepared using a classic Biginelli reaction under mild conditions, without using catalysts and in a solvent-free environment. Single crystals of two solvatomorphs and one anhydrous form of (I) were obtained through various crystallization methods. The anhydrous form, C13H13FN2O3, was found to crystallize in the monoclinic space group C2/c. It showed one molecule in the asymmetric unit. The solvatomorph with included carbon tetrachloride, C13H13FN2O3·0.25CCl4, was found to crystallize in the monoclinic space group P2/n. The asymmetric unit revealed two molecules of (I) and one disordered carbon tetrachloride solvent molecule that lies on a twofold axis. A solvatomorph including ethyl acetate, C13H13FN2O3·0.5C4H8O2, was found to crystallize in the triclinic space group P-1 with one molecule of (I) and one solvent molecule on an inversion centre in the asymmetric unit. The solvent molecules in the solvatomorphs were found to be disordered, with a unique case of crystallographically induced disorder in (I) crystallized with ethyl acetate. Hydrogen-bonding interactions, for example, N-H...O=C, C-H...O=C, C-H...F and C-H...π, contribute to the crystal packing with the formation of a characteristic dimer through N-H...O=C interactions in all three forms. The solvatomorphs display additional interactions, such as C-F...N and C-Cl...π, which are responsible for their molecular arrangement. The thermal properties of the forms were analysed through differential scanning calorimetry (DSC), hot stage microscopy (HSM) and thermogravimetric analysis (TGA) experiments.

Derivatization-based magnetic dummy molecularly imprinted polymers integrated with 4-plex stable isotope labeling derivatization strategy for specific and rapid determination of L-hydroxyproline in human serum

The specific determination of L-hydroxyproline (Hyp) can serve as a potential indicator for early clinical diagnosis of liver fibrosis. In this work, an integrated strategy based on 4-plex stable isotope labeling derivatization combined with dummy magnetic molecularly imprinted polymers (QSILD-DMMIPs) was developed for specific extraction and rapid determination of Hyp in human serum by ultra high performance liquid chromatography tandem mass spectrometry. A new series of QSILD reagents d0/d1/d2/d3-6-N-methyl-rhodamine 6G-N-hydroxysuccinimidyl formate (d0/d1/d2/d3-MRSF) were designed, synthesized and applied for the high-throughput labeling of Hyp in serum samples. The structural analogue derivative of Hyp with 6-N-ethyl-rhodamine 6G-N-hydroxysuccinimidyl formate (ERSF-Hyp) was synthesized and used as a novel dummy template to prepare DMMIPs. The DMMIPs were well characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), fourier transform infrared spectroscopy (FTIR), Brunner Emmet Teller (BET) measurements, thermogravimetric analysis (TGA), X-ray diffraction (XRD), zeta potential and adsorption experiments. All d0/d1/d2/d3-MRSF-Hyp derivatives were conveniently and specifically adsorbed by DMMIPs in magnetic dispersive solid phase extraction procedure before injection. Method validation results including linearity (0.2–100 ng mL−1), limits of detection and quantitation (0.05 and 0.2 ng mL−1), accuracy, precision, stability, matrix effect and derivatization efficiency were satisfactory. The analytical performances benefited from efficient integration of QSILD and specific DMMIPs extraction. The proposed strategy was successfully applied for Hyp determination in human serum of liver fibrosis patients and healthy controls, which was of great significance to early diagnosis.

Hydrogen bonds induced polymorphism of pyrazoline derivative: Crystal structures, thermal and optical-physical properties

In this study, 1-acetyl-3-(3-hydroxyphenyl)-5-(9-anthracenyl)-2-pyrazoline (AHAP) was synthesized and afforded two types of polymorphs. Single crystal X-ray analyses revealed that AHAP molecules connect with each other in a head-to-tail fashion through O-H⋯O hydrogen bonds between the carbonyl and hydroxyl groups. However, through the above intermolecular interactions and stacking mode, the one-dimensional chain motifs are formed in the α polymorph and cyclic tetramers are formed in the β polymorph, which constitute their crystal structures as units. Compared with solvent-free α polymorph, the unit cell of the β polymorph includes a small region of disordered solvent molecules. CrystalExplorer program, Differential scanning calorimetry (DSC) and thermogravimetric thermal analysis (TGA) experiments revealed that the voids should be inside the tetramers and each void contains one disordered solvent molecule. 1H NMR spectra conformed the type of the disordered solvent molecule is consistent with the crystalline liquid phase. The optical-physical properties of the two polymorphs were also investigated. They emit similar fluorescence, which is assigned to monomer emission of anthracene, due to the monomer arrangement of anthracene fluorophores in the two polymorphs.

An experimental and numerical study on the combustion of lignites from different geographic origins

Coal combustion involves multi-scale, multi-phase and multi-component aspects, in a process where both transport phenomena and reaction kinetics must be considered. The aim of the work is to investigate the differences between the combustion characteristics of Turkish (Soma lignite, Tunçbilek lignite, Afşin-Elbistan lignite) and German (Rhenish lignite) lignites. Combustion characteristics of these lignites were investigated experimentally and numerically. Experiments were conducted using a high temperature (1000 °C) and high heating rate (~104 °C/s) drop tube furnace (DTF), along with a thermogravimetric analyzer (TGA) at non-isothermal conditions (5, 10, 15, 20 °C/min). Both experimental trials were done in a dry air environment and atmospheric pressure. Additionally, DTF and TGA are the experimental setups used to validate the numerical model used in this work. The numerical part of the study includes the computational fluid dynamic analysis of DTF and the predictive multi-step kinetic model analysis of the fuel particle. TGA experiments showed that fuel ratio has an effect on the ignition times. Moreover, maximum reaction rates obtained by TGA experiments were inversely proportional to the ash contents of the fuels used. High heating rate DTF experiments showed similar combustion behaviours with TGA experiments. According to DTF experiments, RL has the highest reactivity (RL: 7.8 s−1) among all fuels (AEL: 5.3, SL: 4.7, TL: 2.9 s−1). In comparison to experimental data, PoliMi model predictions on high-temperature volatile yields are satisfactory with 5–7% errors. PoliMi model overpredicted the devolatilization rates whereas char oxidation rate predictions seem to be lower than the experimental results.

High-Performance n -Hexane Purification by Nonporous Adaptive Crystals of Leaning Pillar[6]arene

The production of high-purity n-hexane under mild conditions is of great significance in both the petrochemical industry and synthetic chemistry. Here, we report an easy-to-operate and energy-effic...

Insights into pyrolysis characteristics of Brazilian high-ash sewage sludges using thermogravimetric analysis and bench-scale experiments with GC-MS to evaluate their bioenergy potential

This paper is the first comprehensive report about the renewable fuels produced from the pyrolytic conversion of anaerobic and aerobic Brazilian high-ash sewage sludges. The study was divided into three steps: (1) an in-deep evaluation of physicochemical characteristics of both sewage sludges; (2) thermogravimetric analysis under inert conditions for determining bench-scale pyrolysis conditions; (3) characterization of volatile pyrolytic products from fixed bed reactor using GC/MS analysis. The anaerobic and aerobic sewage sludges present substantial high heating values and high contents of ash and sulfur, which are adverse properties for solid fuels. Regarding the pyrolytic behavior, the sewage sludge samples presented a two-step thermal decomposition process. The bio-oil produced from pyrolysis indicates that the high-ash sewage sludges are a source of high value-added chemicals, such as aliphatic and monoaromatic hydrocarbons. In addition, the pyrolysis can promote the production of a hydrogen-rich syngas for thermal boilers or engines use. In this research, it was demonstrated that the pyrolysis process of Brazilian high-ash sewage sludge can be applied for the production of useful biofuels - as bio-oil and bio-syngas - also adding value to this waste, thus contributing to the establishment of renewable source of bioenergy.

Determination of Pyrolysis Kinetics of Cellulose and Lignin Fractions Isolated from Selected Turkish Biomasses

The pyrolysis behavior of Turkish biomass samples such as hazelnut shell, almond shell, and sunflower stalk residue was studied using a thermogravimetric analysis (TGA) laboratory-scale setup. Biomass samples were characterized using the standard method of the Van Soest detergent analysis, and both the virgin biomass and fractions were investigated. The reaction temperature was increased to 900 °C with a heating rate range between 2 and 60 °C min−1 in the TGA experiments. Seven solid-state reaction models were applied to evaluate the obtained experimental TGA results. The heating rate was not the only parameter affecting the values of activation energy and the ratio of the main components such as the cellulose and lignin of the virgin biomass samples (almond shell, sunflower stalk, and hazelnut shell) also affected the value of the activated energy values. It was determined that a model fitting mechanism gives limited information to determine the exact activation energy values for the samples. The reaction order model provided straightforward and decisive results for all the biomass and lignin samples. Models of two- and three-dimensional diffusion were better suitable for the cellulose devolatilization. It was also determined that the activation energy of the lignin samples was similar regardless of the types of biomass. According to the kinetic calculations, the cellulose samples showed the highest activation energy values and the lignin samples had the lowest.