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The ash content of rubber was determined by thermogravimetric analysis (TGA) and the effects of sample amount, sample representativeness, heating rate, combustion temperature and combustion atmosphere on the test results were studied and the repeatability and reproducibility of the method were determined. The results showed that the optimal conditions of TGA were sample mass between 10 mg and 20 mg, heating rate of 20 ℃/min or 30 ℃/min, combustion temperature for raw rubber and compounded rubber (or vulcanized rubber) of 550 ℃ and 650 ℃, respectively. The repeatability and reproducibility of TGA were all good. When ash mass fraction of 4 types of different rubbers were from 0.29% to 5.12%, the repeatability within laboratory was from 0.110% to 0.303%, and the reproducibility between laboratories was from 0.283% to 0.676%.

Abstract Solid fossil fuels still support the development of the energy and chemical industry. The clean and efficient utilization of solid fossil fuels can effectively alleviate the problems of energy shortage and environmental pollution. An in‐depth understanding of the kinetic process, models, and mechanism of pyrolysis of solid fossil fuels is also of great significance for the exploration and utilization technologies of petroleum resources. Thermogravimetric analysis is an effective method to study the pyrolysis process and kinetics with the advantages of high sensitivity, repeatability, and reliability for data acquisition. Researchers have conducted a lot of research on the thermogravimetric kinetics of solid fossil fuels in recent years, but there is a lack of systematic summary and comparison of kinetic methods, research progress, and trends. Therefore, a comprehensive study on pyrolysis kinetic principles, methods, and models of solid fossil fuels by thermogravimetric analysis is carried out in this paper. The influencing factors of pyrolysis kinetics of solid fossil fuels using thermogravimetry are elaborated and discussed in detail. This study also provides progress in recent years and prospects of thermogravimetric kinetics of solid fossil fuels. It is expected that this paper can provide certain technical support and theoretical guidance for the research on pyrolysis kinetics based on thermogravimetric analysis, and the exploration and development, clean, and efficient utilization of solid fossil fuels.

This study investigates the intricate thermal decomposition behavior and combustion characteristics of two distinct types of wheat straw pellets (WSP) represented as T1 (100 % wheat straw) and T5 (70 % wheat straw; 10 % sawdust, 10 % biochar; 10 % bentonite clay). Through a thermogravimetric analyzer (TGA) the pellets undergo combustion under varying heating rates (5, 10, and 20 °C/min) in an air atmosphere, ranging from 25 to 1200 °C. Differential thermogravimetric and thermogravimetric analyses reveal four distinct stages of decomposition in the biomass components. The results indicate that the optimal combustion heating rate is 20 °C/min, resulting in the highest reaction rate (∼50 %/min) and most substantial mass loss (∼55 %) for both T1 and T5 pellets. Notably, the T5 pellet demonstrates a lower ignition temperature (207 °C, at 20 °C/min) and higher burnout (457 °C at 10 °C/min) compared to the T1 pellet, indicating its superior suitability for combustion. The combustion efficiency ranges from 61.0 to 99 % within the temperature range of 300 to 700 °C, similar to coal combustion. Additionally, thermodynamic properties (Di, Db, C, and S) suggest the promising potential of WSP as a bioenergy feedstock. Furthermore, T1 pellets demonstrate higher ignition temperatures (Ti) than T5, indicative of rapid combustion and lower energy potential. burnout temperatures (Tb) revealed intricate results in both scenarios. These findings hold significance for the design of gasification or combustion reactors and the industrial utilization of WSP biomass. The insights gathered from this study offer valuable guidance for designing and enhancing bioenergy systems and fostering sustainable practices in utilizing agricultural residues for energy production.

Biomass is an organic substance widely available in nature as a fresh or a waste material considered renewable energy that aligns with the zero-carbon scheme to reduce the dependency on fossil fuels. However, after conversion, biomass's physical or chemical properties highly affect biofuel characteristics. A variety of instruments can be used to figure out biofuel reactivity. Considering commonly adopted instruments, thermogravimetric analysis (TGA) is a simple, fast, and efficient way to determine biofuel properties and reactivity. The TGA method has the capability to analyze the biofuel properties (proximate analysis: moisture, volatile matter, fixed carbon, and ash) and combustion features of biomass (such as ignition, reactivity, etc). Most importantly, the TG curvatures (TGA and DTG) reveal the behavior of the biofuel during the thermodegradation process. As a consequence, the quality and quantity analyses on the biofuel properties and reactivity can be investigated comprehensively. Moreover, some TGA integration with artificial intelligence (AI) has been studied to better understand biofuel management and technology for future development. The outcome for the TGA-AI integration may obtain an excellent result with the fit quality value R2 >95 %. This study aims to comprehensively review relevant research using TGA to analyze the lignocellulosic biofuel properties and reactivity. Moreover, the discussion in this study is extended to perspective, challenges, and future work.

Abstract Gilsonite (GLS), a natural bitumen containing a considerable amount of asphaltenes, is expected to leave heavy char after pyrolysis; however, its high potential as an efficient filler to enhance the thermal properties of composite materials is surprisingly neglected throughout the literature. On the other hand, polyfurfuryl alcohol (PFA) has attracted much attention as a thermosetting resin due to its excellent char-leaving characteristics, the renewable nature of the monomer(s), and high accessibility at an affordable cost. This study aimed to investigate the thermal stability and char-forming performance of composites made of a PFA resin matrix filled with chemically modified GLS. To modify the ash and sulfur contents of GLS, the nitric acid leaching process was performed according to a D-optimal experimental design approach. The nitric acid concentration (10, 20, and 30 wt.%), treatment time (30, 75, and 120 min), and reaction temperature (30 °C, 50 °C, and 70 °C) were set as the input variables. The morphology (SEM), chemical structure (FTIR), thermal stability (TGA), sulfur content, and ash content of the GLS particles were characterized before and after acid treatment. Thermogravimetric analysis revealed the lowest ash content for GLS after treatment with 10 wt.% acid conc. at 75 °C for 75 min. The nitric acid concentration, reaction temperature, and time were the most influential parameters for improving the ash content of GLS according to their order of appearance. In addition, the inorganic form of sulfur, pyrite, was separated through the acid leaching process. Then, the PFA resin matrix was filled with modified GLS particles at different weight percentages (5, 10, 15, and 20 wt.%) and cured in the presence of an acid catalyst. The thermal stability of the PFA resin was negatively affected by the presence of GLS, probably due to oxidation reactions and disruption of the integrity of the resin structure.

Tetra Pak® paper and PE (polyethylene) wastes were evaluated to obtain a new composite material with awareness of environmental responsibility. Fillers and coupling agents were used for this joining process. Calcite (CaCO3), boric acid (H3BO3), SPT (Sodium Perborate Tetrahydrate / NaBO3.4H2O), titanate, MAPE (maleic anhydride grafted polyethylene, and vinyltriethoxysilane (C8H18O) composites were produced in 30 × 30 cm plates. A total of 30 samples were prepared as 5 mg flour for thermogravimetric analysis (TGA). Samples were observed in a thermal analyzer at 10, 15, or 20 °C/min heating rate in nitrogen atmosphere. Graphs were obtained as a result of TGA, and the activation energies were calculated using these graphs. The activation energy was calculated using the Flynn-Wall-Ozawa method. The determined activation energies of the composites were close to each other for each temperature group. In the samples using calcite and vinyltriethoxysilane, relatively higher activation energies were observed in comparison to the samples with boric acid and MAPE.

Abstract The enhanced coalbed methane recovery using CO2 injection (CO2-ECBM) is widely proposed as a way of achieving the energy transition and reducing atmospheric CO2 in areas such as the Lorrain basin in France, where heavy industry is responsible for huge CO2 emissions and coal mines have been closed for more than a decade. This paper deals with the feasibility of extracting methane from the Lorraine basin using CO2-ECBM by comparing data from sorption isotherms, thermogravimetric analyses and breakthrough curves for two coal samples. One is bituminous (Box 18), from Folschviller (France) and is compared with another sub-bituminous (TH01) from La Houve (France), which is used as a reference because it was identified as a good candidate for CO2-ECBM in a previous research program. The quantities of adsorbed gases (CO2/CH4) obtained by sorption isotherms, thermogravimetry and CO2 breakthrough curves showed that Box 18 adsorbs more CO2 and CH4 than TH01 due to its higher porosity and good affinity for gases (CO2/CH4). Tόth model fits the experimental CH4 and CO2 adsorption isotherms better, reflecting the fact that the adsorption surface of the coals studied is heterogeneous. Adsorption enthalpies obtained by calorimetry indicated physisorption for gas-coal interactions, with higher values for CO2 than for CH4. Thermogravimetric analyses and breakthrough curves carried out at up to 50% relative humidity showed that the adsorption capacity of CO2 decreases with increasing temperature and the presence of water, respectively. The compilation of these experimental data explained the adsorption process of the studied coals and revealed their advantages for CO2-ECBM.

Composite polymers are an interesting class of materials with a wide range of applications. Among the properties of polymers which are currently being enhanced via the development of composite materials is their thermal stability, which is typically evaluated via thermogravimetric analysis (TGA). In this work, a paradox is recognized regarding the considered relationship between the polymer–filler interactions leading to a good dispersion of the filler and the improvement of thermal stability. Simulation of the TGA signal during isothermal measurements of composite polymers is performed along with experimental measurements. It is shown that there are at least three factors that can cause apparent alterations of the thermal stability of composite polymers, namely, the different buoyancy due to the different densities of the composites and the neat polymer, the different thermal diffusivity of the composites and the fact that the mass loss (or remaining mass) of the composites, conventionally, is expressed per overall mass of the composite and not per mass of polymer. The relative contributions of these factors are evaluated and it is found that the conventional expression of mass loss has the most profound effect. Furthermore, it is shown that it is proper to express and evaluate the TGA results of composite polymers per degradable (polymer) mass of the composite and not per overall mass of the composite.