Thermal Kinetic Parameters Research Articles

Comparison of pyrolysis and anaerobic digestion processes for wheat straw biomass

Due to the growing interest in using biomass as a renewable energy source, this study presents a comparative analysis between two prominent biomass conversion technologies—anaerobic digestion and biomass pyrolysis—focused on wheat straw biomass. The objective of this study is to evaluate and compare the efficiency, energy output, and environmental impact. Anaerobic digestion was performed under mesophilic conditions (35 ± 0.5 °C) using the biochemical methanogenic potential (BMP) methodology. Pyrolysis was conducted through thermogravimetric analysis (TGA) to determine the thermal behaviour and kinetic parameters of the biomass. Biogas production led to better energetic results as high methane yields of over 11 mL CH₄ g⁻¹ VS were obtained. Additionally, the integration of both processes was considered by subjecting digestate from anaerobic digestion to pyrolysis process. Key findings demonstrate that the activation energy (Ea) for wheat straw ranged from 166.49 to 176.42 kJ·mol−1 across different kinetic methods, indicating its suitability for pyrolysis. In contrast, digestates exhibited significantly lower activation energies, with 1-week, 2-weeks, and 3-weeks digestates showing ranges of 53.27–60.79 kJ·mol−1, 38.69–46.86 kJ·mol−1, and 46.29–72.34 kJ·mol−1, respectively. These results suggest that anaerobic digestion not only produces biogas but also yields a byproduct with potential for efficient pyrolytic conversion suggesting opportunities for integrated waste management and renewable energy production systems.

ESR-thermochronometry of the MIZ1 borehole, Tono, Japan

Previous studies have shown that the low-relief Tono region (Japan) underwent Quaternary exhumation at rates of <1 mm yr-1. Here we explore whether electron spin resonance (ESR) signals of quartz from six samples from the MIZ1 borehole can resolve such low rates of exhumation, or whether the samples are in thermal equilibrium with ambient borehole temperature. ESR thermochronometry requires that both sample-specific signal saturation and thermal decay are constrained in the laboratory, which makes measurements highly time-consuming. To overcome this, the development of a standardised growth curve (SGC) was explored, which allowed more rapid constraint of the trapped-charge concentrations of each of the samples. Thermal kinetic parameters were determined using an isothermal decay experiment for each individual sample and except for sample MIZ1-01, it was possible to fit all the isothermal decay data together to yield a single set of kinetic parameters that successfully described the dataset. Using a single set of kinetic parameters also allows faster measurement. The ESR thermochronometry results show that the MIZ1 samples are not in thermal equilibrium, but rather reflect ongoing exhumation in this region. Exhumation rates determined from the Al-centre are consistent with existing thermochronometric data and indicate total exhumation of 385 ± 220 m over the past 1 Myr. In contrast the different Ti-centre options (A, B, D) yield a total exhumation of ∼1 km over the same period. The cause of this discrepancy is unclear but may relate to sub-linearity of Ti-centre dose response, that lead to underestimation of the trapped-charge concentration and hence an overestimation of exhumation rates. Our results indicate that ESR-thermochronometry can be successfully applied in low-relief zones undergoing exhumation at rates <1 mm yr-1, and that an SGC and common thermal kinetic parameters may be used to expediate sample measurements.

Experimental Study on the Thermal Behavior Characteristics of the Oxidative Spontaneous Combustion Process of Fischer–Tropsch Wax Residue

Coal-to-liquid technology is a key technology to ensuring national energy security, with the Fischer–Tropsch synthesis process at its core. However, in actual production, Fischer–Tropsch wax residue exhibits the characteristics of spontaneous combustion due to heat accumulation, posing a fire hazard when exposed to air for extended periods. This significantly threatens the safe production operations of coal-to-liquid chemical enterprises. This study primarily focuses on the experimental investigation of the oxidative spontaneous combustion process of three typical types of wax residues produced during Fischer–Tropsch synthesis. Differential Scanning Calorimetry (DSC) was used to test the thermal flow curves of the three wax residue samples. Kinetic analysis was performed using the Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO) methods to calculate their apparent activation energy. This study analyzed the thermal behavior characteristics, exothermic properties, and kinetic parameters of three typical wax residue samples, exploring the ease of reaction between wax residues and oxygen and their tendency for spontaneous combustion. The results indicate that Wax Residue 1 is rich in low-carbon chain alkanes and olefins, Wax Residue 2 contains relatively fewer low-carbon chain alkanes and olefins, while Wax Residue 3 primarily consists of high-carbon chain alkanes and olefins. This leads to different thermal behavior characteristics among the three typical wax residue samples, with Wax Residue 1 having the lowest heat release and average apparent activation energy and Wax Residue 3 having the highest heat release and average apparent activation energy. These findings suggest that Wax Residue 1 has a higher tendency for spontaneous combustion. This research provides a scientific basis for the safety management of the coal chemical industry, and further exploration into the storage and handling methods of wax residues could reduce fire risks in the future.

Exploring the use of averaged thermal kinetic parameters in luminescence thermochronometry

In luminescence thermochronometry, the thermal stability of feldspar minerals is conventionally constrained from isothermal decay experiments. However, despite recent refinement of the measurement protocol, measurements take several days and are routinely done for each individual sample. Following that most other thermochronometric methods usually use only a single reference set of thermal kinetic parameters, and that recent studies on direct physical probing of feldspar sample properties have shown that trap depth and band-tail width are broadly similar despite large variations in chemical composition, we sought to optimise luminescence thermochronometry measurements by exploring whether a single set of thermal kinetic parameters can describe luminescence thermal decay in feldspar. We explored the effect of using averaged thermal kinetic parameters rather than sample-specific thermal kinetic parameters to model luminescence signal accumulation under different thermal conditions. A set of K- and Na-feldspar minerals extracted from all over the world were analysed after being measured with a multi-elevated temperature protocol, comprising four different IRSL signals at 50, 100, 150, and 225 °C. Comparisons were done between the thermal kinetic parameters of each IRSL signal depending on different variables such as geographic region, transect, lithology, or mineralogy of the analysed feldspar grains. Even though it is not possible to generalise the thermal kinetic parameters between IRSL signals measured at different temperatures, the variance between the thermal kinetic parameters of different samples measured at the same IRSL temperature is consistent with the uncertainties on the individual parameters (i.e., <2–10%), suggesting that averaged, rather than sample-specific values may be appropriate. We then explored the effect of using these averaged parameters to model luminescence signal accumulation under different synthetic and natural thermal conditions. For our dataset, results show minimal impact on the obtained cooling histories and exhumation rates. We therefore propose the use of averaged rather than sample-specific thermal kinetic parameters for rapid investigation of luminescence thermochronometry samples. Based on careful initial characterisation of a few samples to verify the validity of using averaged thermal kinetic parameters, this would reduce measurement times by ca. 50% (i.e., 3–4 days per sample), allowing higher resolution sampling and measurement.

Validation of a Simulated Commercial English Muffin Baking Process to control Salmonella Contamination

A validation study was conducted to investigate the effect of the English muffin baking process to control Salmonella contamination and to study the thermal inactivation kinetic parameters (D- and z-values) of Salmonella in English muffin dough. The unbleached bread flour was inoculated with 3 serovar Salmonella cocktail (Salmonella serovars viz., Newport, Typhimurium, and Senftenberg), and dried back to its preinoculated water activity levels with 7.46 ± 0.12 log CFU/g of Salmonella concentration. The Salmonella inoculated flour was used to prepare English muffin batter and baked at 204.4°C (400°F) for 18 min and allowed to cool at ambient air for 15 min. The English muffins reached 99 ± 0°C (211.96 ± 0.37°F) as their maximum mean internal temperature during baking. The pH and aw of English muffin dough were 5.01 ± 0.01 and 0.947 ± 0.003, respectively. At the end of the 18−min baking period, the Salmonella inoculated English muffins recorded a more than 5 log CFU/g reduction on the injury-recovery media. The D-values of 3 serovar cocktails of Salmonella at 55, 58.5, and 62°C were 42.0 ± 5.68, 15.6 ± 0.73, and 3.0 ± 0.32 min, respectively; and the z-value was 6.2 ± 0.59°C. The water activity (aw) of the English muffin crumb (0.947 ± 0.003 to 0.9557 ± 0.001) remained statistically unchanged during baking, whereas the aw of the muffin crust decreased significantly (0.947 ± 0.003 to 0.918 ± 0.002) by the end of 18 min of baking. This study validates and documents the first scientific evidence that baking English muffins at 204.4°C (400°F) for 18 min acts as an effective kill step by controlling Salmonella population by >5 log CFU/g.

Design and evaluation of a kind of polymer-bonded explosives with improved mechanical sensitivity and thermal properties

The emergence of TKX-50, an energetic ionic salt with a high enthalpy of formation and low sensitivity, has opened a new path for the development of high-energetic, insensitive composite explosives. However, due to the poor interfacial binding properties of TKX-50 with conventional binders, there is a lack of effective guidance for the design of TKX-50 based composite explosives. To address the above issues, the interactions between carboxymethyl cellulose acetate butyrate (CMCAB) and other binders with explosives TKX-50/HMX were compared using the molecular dynamics method. Based on the simulations, TKX-50/HMX/CMCAB-based polymer-bonded explosives (PBXs) were prepared with CMCAB as binder, which displays a high binding energy (Ebind) with TKX-50 and high cohesive energy density (CED), and the effect of TKX-50 content on the performance of PBXs was investigated. The physical properties of PBXs, specifically the morphology, mechanical sensitivity, and thermal conductivity, were analyzed by SEM, sensitivity apparatus, and thermal conductivity meter, respectively. The specific heat capacity (Cp) and non-isothermal decomposition temperature of PBXs were tested by DSC, and then the corresponding thermal kinetic parameters were analyzed to evaluate their thermal safety. The adiabatic thermal decomposition processes of PBXs were tested using an ARC instrument. The decomposition mechanism and kinetics were also explored to further analyze their thermal stability and thermal safety under adiabatic conditions. The computer code EXPLO5 was used to predict the detonation parameters of PBXs. The results showed that CMCAB and TKX-50 displayed favorable interfacial bonding properties, and TKX-50 can be bonded with HMX to form a molding powder with a desirable morphology and safety profile. The TKX-50 in PBXs effectively improves the mechanical sensitivity and thermal safety of PBX and has a significant effect on the detonation performance of PBX. This research demonstrates a novel method suitable for screening and investigating high-energetic insensitive explosive systems compatible with TKX-50.

Synthesis, structural and antimicrobial studies of transition metal complexes of a novel Schiff base ligand incorporating 1,2,4-triazole and 4-(benzyloxy)benzaldehyde moieties

A Schiff base ligand named 4-(((5-mercapto-4H-1,2,4-triazole-4-yl)imino)methyl)-(benzyloxy)benzene (HL) and its bioactive series of Ni(II), Cu(II), Zn(II) and Cd(II) metal complexes having 1:1 and 2:1 ligand-to-metal ratio, have been synthesized. All the synthesized compounds were fully characterized by IR, 1H-NMR, elemental analysis, absorbance (UV-Vis.) and mass spectra. Furthermore, the molecular structure of the Schiff base was established by single-crystal X-ray diffraction analysis. Additionally, computational investigations of the compounds were conducted using the DFT/B3LYP method. This analysis involved the determination of FMO energy values, as well as the calculation of quantum chemical parameters. The binding effect of metal ions on the ligand's fluorescence intensity was probed using fluorescence spectroscopy. The thermal stability and kinetic parameters of the complexes were determined using TGA (Thermogravimetric Analysis) analysis via the Coats–Redfern method. The docking studies, actively explored the interaction between Schiff base ligand and protein receptor molecules of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. To assess the therapeutic potential, an in silico ADMET model was employed, revealing that the synthesized molecules exhibit drug-like properties. The Schiff base and all the derived metal complexes were screened for their antimicrobial potential against bacterial species like Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and fungus Candida albicans.

An in-depth investigation on the presence of methanol in Garcinia cambogia fruits and rinds: Role of pectin methyl esterase and indigenous fungi

The presence of methanol in fruits is a concern due to its toxicity and the consequent health implications. Garcinia cambogia fruits and Garcinia cambogia rinds showed methanol at 238 ± 15.07 and 355 ± 18.21 ppm, respectively. The enzyme, pectin methyl esterase (PME), associated with production of methanol was also detected with an activity 5.63 ± 0.41 and 2.75 ± 0.14 U/mL, respectively, in fruits and rinds. Furthermore, a fungi isolated from Garcinia cambogia, and identified as Aspergillus aculeatus by morphology and 18S rRNA gene/ITS/D1-D2 (∼700 bp) sequencing, also produced extracellular PME (7.67 ± 0.76 U/mL) at pH 3 to yield 166 ± 5.74 ppm methanol. The molecular weight of partially purified PMEs with 60–70 % ammonium sulphate from G. cambogia fruits, G. cambogia rinds and A. aculeatus of was ∼45, ∼25, and ∼35 kDa, could produce 55.33 ± 2.74, 41.67 ± 0.86, and 74.67 ± 0.19 ppm methanol, and displayed maximum activity at pH 7, 7 and 5, and 35 °C, 35 °C and 40 °C, respectively. The enzyme kinetics, (Km and Vmax), thermal inactivation kinetic parameters (kd, t1/2 and d-value), and thermodynamic parameters (Ed, ΔH°, ΔG°, and ΔS°) of PME from A. aculeatus were superior over PME from G. cambogia fruits and G. cambogia rinds. This investigation confirmed the production of both PME and methanol by both fungi and G. cambogia.

An Experimental Study and Numerical Simulation Analysis of Thermal Oxidation Characteristics Based on Kinetic Parameters in Heavy Oil Reservoirs

In situ combustion (ISC), an efficient and economical method for enhancing heavy oil recovery in high-pressure, high-viscosity, and thermally challenged reservoirs, relies on the kinetics of crude oil oxidation. Despite an increased focus on kinetic models, there is a gap in understanding how oxidation kinetic parameters impact ISC effectiveness in heavy oil reservoirs. This study addresses this by selecting heavy oil samples from the G Block in the Liaohe oilfield and the M Block in the Huabei oilfield and conducting ramped temperature oxidation (RTO), pressure differential scanning calorimetry (PDSC), and thermogravimetric analysis (TGA) experiments. RTO detailed the thermal conversion process, categorizing oxidation into low-temperature oxidation (LTO), fuel deposition (FD), and high-temperature oxidation (HTO) stages. PDSC and TGA provided thermal characteristics and kinetic parameters. The feasibility of fire flooding was evaluated. Using CMG-STARS, an ISC model was established to analyze the impact of kinetic parameter changes. Activation energy significantly affected coke combustion, while the pre-exponential factor had a notable impact on cracking reactions. The recommended values for activation energy and the pre-exponential factor are provided. This study not only guides fire flooding experiments but also supports field engineering practices, particularly for in situ combustion in heavy oil reservoirs.

Oxidation Mechanism and Surface Characterization of Pyrolytic Graphite in Simulated Air for Pyrochemical Reprocessing Application

Accidental air ingress into the containment chamber of pyrochemical reprocessing of spent nuclear fuels can cause severe oxidation of graphite components. Pyrolytic graphite (PyG) coating on conventional high-density graphite (HDG) is proposed for protection against oxidation, molten salt, and molten metal corrosion. The aim of the present study is to evaluate the thermal stability and kinetic parameters and propose a suitable oxidation mechanism of PyG under simulated air using thermogravimetry analysis (TGA). In dynamic oxidation, a linear increase in the oxidation onset, peak, and burnout temperature is observed for PyG synthesized at increasing pyrolysis temperature from 1200 to 2400°C except for 1400°C. The isothermal oxidation study showed a similar trend i.e., a decrease in the linear oxidation rate constant value for any given isotherm with increasing pyrolysis. The Arrhenius plot showed two-stage oxidation regimes operating between 600 to 1000°C. In regime-I, between 600 to ∼800°C controlled by surface chemical reaction kinetics, the activation energy is measured between 100-200 kJ.mol−1. The graphite-oxygen reaction initiates and propagates preferentially along the prismatic planes at the sample edges, where the dangling bonds of stacked graphite layer structures are exposed. In regime-II operating above ∼800°C, the surface reaction rate is infinitely faster, and the diffusional mass transport becomes a rate-limiting factor. In this regime, the graphite-oxygen initiates by pore formation on defective reactive sites on the bulk surface and propagates by pore-widening and pore-coalescence mechanism. The observed differences in the oxidation rates for different pyrolysis PyG attributed to its intrinsic material properties are investigated. This work provides new insights into the oxidation mechanism of the PyG during accidental air ingress in a pyrochemical reprocessing plant.

A meta‐analysis of the global growth and thermal inactivation parameters of Staphylococcus aureus for dairy products

SummaryStaphylococcus aureus is a prominent foodborne pathogen causing Staphylococcal food poisoning (SFP) in dairy products. This study estimated S. aureus growth and thermal inactivation kinetic parameters and variability in various dairy products by conducting a meta‐analysis. Cheese exhibited a lower theoretical minimum temperature (Tmin), indicating favourable conditions for S. aureus growth even at lower temperatures. Tmin values for other matrices ranged from 5.0 to 7.2 °C, providing insights for production parameter formulation. Meanwhile, significant variations in the maximum population density (Ymax) are among dairy products at the same temperature. Keeping temperatures below 0 °C in pasteurised milk, raw milk and cheese limited Ymax to approximately 102–4 CFU mL−1, below the international toxicity threshold. Factors influencing D values were smaller than strain variability, and NaCl concentration emerged as a significant factor affecting S. aureus growth. These parameters can serve as references for quality control, safety and production optimisation in dairy product processes.

Thermal kinetic parameters based classification method of residual waste oriented for efficient energy utilization

Thermal kinetic heterogeneity of mixed residual waste (RW) is a serious problem leading to unsatisfactory efficiency and stability during energy utilization processes. This work proposed a thermal kinetic parameters based classification method of RW. Considering the significant relevance between kinetic parameters and elemental compositions, the latter were used as indicators to establish the sorting principle. The proximate analysis results and kinetic parameters among the new categories were analyzed, the kinetic heterogeneity reduction performance versus the traditional classification method was compared, and the working mechanism of the proposed classification method was discussed. Three new RW categories were obtained, and the composition and kinetic parameters among these new categories have significant difference (P < 0.05). The kinetic heterogeneity was reduced compared with the traditional classification method. The absolute value of Pearson correlation coefficient between elemental composition and kinetic parameters could reach 0.8, proving the mechanism of the new classification method. The study is hopeful to facilitate efficient energy utilization of RW.

Investigating the catalytic effect of nanoferrites additives on the thermal decomposition of ammonium perchlorate and burning rate modification of the composite solid propellants

The co-precipitation method was used to synthesize nanosize copper ferrite (CuF) and cobalt-copper-nickel ferrite (CoCuNiF). Physico-chemical characterization of material was done using powder X-ray diffraction, Raman, UV–Vis, and atomic force microscopy (AFM). The effect of 1 % by mass additives on the thermal decomposition and kinetics parameters of ammonium perchlorate (AP) was investigated using non-isothermal isoconversional methods such as Flynn wall Ozawa (FWO), Kissinger Akahira Sunose (KAS), and Starink. The burning rate enhancement and ignition delay study were also investigated. The catalysts can decrease the activation energy of AP by 48 % along with increasing the burning rate of the corresponding composite materials. Both the catalysts can be successfully used for enhancing the burning performance of propellants and hence can be used for rocket and missile propulsions.

Development and application of a semi-detailed model for lithium-Ion battery thermal runaway chemistry

To overcome the disadvantages of detailed methodologies and existing simple methodologies for modeling lithium-ion battery thermal runaway chemistry, a semi-detailed model has been developed in the present work. This is important for mitigating battery thermal runaway. The semi-detailed model contains two parts: a ‘global part’ and an ‘elementary reaction mechanism part’. The thermal kinetics parameters of a recently published model are improved so that it can be selected for the ‘global part’ to model NCM811 (LiNi0.8Co0.1Mn0.1O2), NCM622 (LiNi0.6Co0.2Mn0.2O2), and NCM532 (LiNi0.5Co0.3Mn0.2O2). Temperature and heat release evolutions during battery thermal runaway can be obtained from the simulation of the ‘global part’. In the ‘elementary reaction mechanism part’, 53 reactions with frequency factors and activation energies have been proposed and adopted for describing flammable gas formation, lithium-ion consumption, gas phase interaction, and lithium-ion gas interaction during battery thermal runway. Detailed processes for coupling the ‘global part’ and the ‘elementary reaction mechanism part’ as well as solving the 53 reactions are developed, which is the major novelty of this work. Through the coupling of the two parts, chemical venting gas species generation and lithium-ion consumption during the transient thermal runaway process of an NCM811PC (LiNi0.8Co0.1Mn0.1O2 polycrystalline) pouch cell with nail penetration were calculated and compared with available experimental data in the literature. The comparison shows that the semi-detailed model can give correct species trends, indicating the two parts and their coupling in the semi-detailed model of the present work are reliable. The simulation results with transient venting gas chemical species provide useful insights for stopping or delaying battery thermal runaway.

Brewers spent grain drying: Drying kinetics, moisture sorption isotherms, bioactive compounds stability and Bacillus cereus lethality during thermal treatment.

The most abundant by-product of the brewing industry is beer bagasse (BSG); its high moisture content requires a rapid drying process to stabilize the product. The objective of this work was to carry out the analysis and mathematical modeling of the drying process of thin layer bagasse at temperatures above 60 °C in order to establish adequate processing conditions that assure its safe use and storage as a functional ingredient. The moisture sorption isotherms of BSG were determined at 10, 20 and 40 °C. Considering the most unfavorable condition tested (40 °C), the maximum residual moisture content that avoids the growth of Bacillus cereus was 15% dry basis, that corresponds to aw = 0.93. The drying curves of thin layers of BSG were obtained experimentally and mathematically modeled using Fick's law; lethality to achieve at least a 2-log reduction in Bacillus cereus population was assessed in terms of thermal inactivation kinetic parameters. Drying conditions at temperatures above 75 °C with air velocity of 3.2 m/s, increased total phenol content levels enhancing antioxidant activity.

Low-oxygen Ti-6Al-4V alloy powder synthesized by an aluminothermic reduction combined with deoxidation process

A novel aluminothermic reduction combined with deoxidation process was developed in this research to prepare low-oxygen Ti-6Al-4V alloy powder. First, with Al and Al-V alloy powders as reducing agents and additives, crude Ti-6Al-4V alloy powder was fabricated by reduction-vacuum distillation using Na2TiF6 as a titanium source. The aluminothermic reduction process was investigated by TG-DSC technique, and the thermal kinetic parameters of the reaction process were calculated by the Kissinger method. The oxygen content of the crude Ti-6Al-4V alloy powder with a coral-like porous structure was detected as 0.366 %. Furthermore, the existential states of the oxygen contained in the crude product powder was analyzed using XPS. The results indicated that the oxygen existed in three chemical states: metal oxides, defective oxygen, and adsorbed oxygen. Therefore, the deoxygenation of the crude Ti-6Al-4V alloy powder with calcium as a deoxidizer was carried out at 900 °C. As a result, the final Ti-6Al-4V powder with an oxygen content of approximately 822 ppm could be obtained. The contents of Ti, Al, V, Fe, and O in the obtained Ti-6Al-4V powders met the requirements of GB/T 3620.1−2016. This work had demonstrated the feasibility of preparing Ti-6Al-4V alloy powder by the novel aluminothermic reduction combined with deoxidation process.

Effect of different pre-treatment techniques on thermogravimetric characteristics and kinetics of lignocellulosic biomass pyrolysis

In this study, effect of pre-treatments on biomass pyrolysis kinetics was evaluated. Fir wood sawdust (F), pine wood sawdust (P) and hazelnut shell (H) were selected as raw biomass sample. Acidic pre-treatment was applied by using 1M-H2SO4 at room conditions and hydrothermal pre-treatment applied by using high pressure and temperature reactor. Thermogravimetric analysis was executed to specify thermal degradation behavior of the samples. Thermogravimetric analysis was also used to determine kinetic parameters of thermal degradation for biomass and pre-treated biomass samples. Having knowledge thermal degradation behavior and kinetic parameters of pyrolysis process such as activation energy and reaction rate are very important for reactor design. Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (OFW) and Coats-Redfern (CR) methods were used to investigate the effect of different pre-treatment techniques on the kinetic parameters. Activation energies of pyrolysis reactions for F, P and H were found as 158.47 ± 1.08 kJ/mol, 126.0 ± 1.78 kJ/mol and 158.66 ± 1.24 kJ/mol, respectively. The calculated activation energy values increased while acidic and hydrothermal pre-treatment were applied to each biomass samples. In conclusion, acidic and hydrothermal pre-treatments influenced the serial and parallel reaction rates during the thermal degradation process and the calculated activation energy values changed accordingly. Inorganics that catalyzed the pyrolysis reactions were removed by acid pre-treatment. The condensed species during hydrothermal pre-treatment prevented the easy volatilization. As a result of experimental studies and kinetic calculations, it has been determined that pre-treatments applied to biomass increased the activation energy value in thermal degradation reactions.

Investigation of Curing Process and Thermal Behavior of Copolymers Based on Polypropylene Glycol Fumarate and Acrylic Acid Using the Methods of DSC and TGA.

In this work, the possibility of preparation of copolymers of three-dimensional crosslinked structure based on polypropylene glycol fumarate and acrylic acid is shown. The initial reagent polypropylene glycol fumarate has been synthesized by polycondensation reaction of fumaric acid and propylene glycol. The curing process of polypropylene glycol fumarate and acrylic acid at various mole concentrations was studied using DSC method at isothermal and dynamic regimens. Curing in isothermal condition was carried out at temperatures of 60 °C, 70 °C, and 80 °C. Residual reactivity was evaluated at a dynamic regimen within the temperature range from 30 °C to 200 °C at a constant heating rate. On the basis of calorimetric studies, the thermal effects and kinetic parameters of the reaction (conversion, reaction rate, activation energy) have been determined. Thermal behavior of cured samples of p-PGF-AA was estimated using dynamic thermogravimetry (TGA). According to TGA data, the process of decomposition of the studied copolymers proceeds in several stages. Based on the results obtained, the activation energies of thermal decomposition were calculated using the iso-conversional methods of Kissinger-Akakhira-Sunose and Friedman.

Thermal conversion performance, kinetic mechanism, and products of electric vehicle lithium battery diaphragms

The proliferation of waste lithium batteries is on the rise; however, the thermal treatment attributes of these batteries are largely overlooked, and the conversion mechanism of lithium battery separators remains unclear. This study marks the first comprehensive to compare the thermal degradation characteristics, kinetic parameters and mechanisms, thermal degradation products, and degradation pathways of polypropylene (PP) and polyethylene (PE) lithium battery diaphragms. The pyrolysis temperatures for the PP and PE were 340–500 and 440–530 °C, respectively. PP and PE exhibited average activation energies of 65.19–73.04 and 207.62–209.40 kJ/mol, respectively. At 600–800 °C, the yields of PP and PE pyrolysis gases and gasoline products increased with increasing temperature, while the yields of diesel and paraffin products decreased. The most dominant products generated from the pyrolysis of PP and PE were olefins, and the amount of olefin products from PE increased with increasing pyrolysis temperature. CH3 fracture was the first reaction step that occurred during PP pyrolysis. Our study provides useful information for industrial recycling, disposal, and utilization of electric vehicle lithium battery separators as well as data on the pyrolysis behaviours and transformation mechanisms of polyolefin wastes.

Growth and Characterization of Organic 2-Chloro 5-Nitroaniline Crystal Using the Vertical Bridgman Technique

In this article, we discuss the preparation of organic 2-chloro-5 nitroaniline (2C5NA) crystals and their different kinds of physical, chemical, and mechanical properties. The vertical Bridgman approach was used to effectively produce the bulk organic 2C5NA crystal. To produce a good-quality bulk crystal, the shape, dimensions, and cone angle of the ampoule were optimized. Also, the temperature profile was set for the 2C5NA crystal. The growth atmosphere and the lowering rate were identified to obtain a homogeneous mixture of the compounds and initiate the nucleation process. Single-crystal X-ray diffraction (XRD), powder XRD, proton Fourier transform nuclear magnetic resonance (FT-NMR), and Fourier transform infrared investigations were used to confirm the crystal structure, molecular structure, and presence of functional groups in the formed crystal. The formed crystal has a monoclinic crystal structure with the space group P21/c, according to single-crystal XRD analysis. The thermal stability and kinetic parameters were examined using thermogravimetric analysis and differential thermal curves. From dielectric analysis, the electrical conductivity and dielectric behavior of 2C5NA were investigated with variations in frequency and temperature. The organic 2-chloro-5-nitroaniline crystal demonstrates that the indentation size effect is observed in the Vickers micro-hardness test, which was also carried out.