Flynn-Wall-Ozawa Research Articles

Curing and degradation kinetics of crosslinked epoxidized soybean oil with isosorbide-based curing agent

This work explores the synthesis of the isosorbide-based curing agent with methyltetrahydrophthalic anhydride (MTHPA). Synthesized for the first time, the isosorbide methylphthalate acid (IMPA) and its effects on the crosslinking of epoxidized soybean oil (ESO) are investigated. The curing and degradation kinetics of the synthesized compounds were investigated for molar ratios 1:1, 1:0.50 and 1:0.25 for ESO/IMPA and 1:1 ESO/MTHPA. ESO/IMPA 1:0.50 had the lowest cure activation energies during the highest cure conversion range, between 10% and 55%, and the highest degradation activation energies during the 30 and 60% conversion. The Friedman and Vyazovkin isoconversional models provided R2 > 0.99 for cure, except for the ESO/MTHPA composition, presenting a lower R2. In degradation kinetics, the Kissinger-Akahira-Sunose (KAS) and Ozawa-Flynn-Wall (OFW) kinetic models presented R2 > 0.99, while the degradation mechanisms were adequately adjusted with Avrami-Erofeev (An) and autocatalytic (n,m)th order (Cnm) during the first and second degradation step. Microstructural analyzes and deeper investigations into the degradation mechanisms in the solid state indicated that in the ESO/IMPA and ESO/MTHPA compounds the processes are controlled by diffusion.

Study on the Influence of Porous Gel on Coal Pyrolysis Performance Based on Experiments and Molecular Simulation

ABSTRACT Studying the kinetics of pyrolysis in pure coals and mixed coals (coals treated with porous gel) holds immense significance in effectively preventing and controlling the spontaneous combustion occurrences in coal. Firstly, porous gel materials were prepared based on physical mixing and chemical crosslinking reaction. Then, based on the thermogravimetric analysis method, the pyrolysis mechanism of porous gel in coal was studied using Flynn-Wall-Ozawa(FWO), Kissinger-Akahira-Sunose(KAS) and Coats Redfern models. Determine the mechanism of coal pyrolysis reaction using the Reaxx FF MD reaction mechanics model. Finally, the inhibition mechanism of porous gel on coal is analyzed through leading temperature rise experiment. The main reaction mechanisms of coal pyrolysis are the diffusion model in the low-conversion-rate range (D4), the R2 and R3 in the high-conversion-rate range, and the Avrami erofeev model (A2, A3). The molecular simulation results indicate that increasing the heating rate can accelerate the rate of coke cracking.

Hydrothermal carbonization of corncob for hydrochar production and its combustion reactivity in a blast furnace.

A key factor restricting the application of biochar in the steel industry is its high-quality upgrading. This paper evaluated the characteristics of hydrochar produced by HTC (hydrothermal carbonization) process of corncob to be used as a solid fuel. HTC temperatures (240-300°C) and HTC water-reused times (1-3 times) were examined for their effects on hydrochar yield, physicochemical characteristics, and combustion properties. The results showed hydrochar yields, O/C, and H/C parameters decreased as HTC temperature and water-reused times increased, while its high heating value increased. Due to dehydration and decarboxylation, hydrochar showed similar characteristics to those in bituminous coal. The removal efficiency of alkali metal K reached 99% after HTC treatment. Carbonaceous hydrochar had become more compact, orderly, and stable with increasing amounts of aromatic functional groups, C = C, and C = O. Hydrochar, as a biofuel, has higher ignition energy and is more stable than corncob due to its high carbonaceous order degree. To calculate combustion kinetic parameters, the Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods were applied. The results revealed that Eα (average activation energy) was quite similar between the two models. HC-300 had an Eα of 262kJ/mol. HTC could be an efficient way to reutilize corncob biomass into clean biofuels with high calorific value.

A comparative study on kinetic and thermodynamic studies for pyrolysis of corn-cob with and without aluminium oxides catalyst using thermogravimetric analysis

ABSTRACT The utilization of corncob residues in pyrolysis offers a promising source for both renewable energy and chemical production. In this study, corncob was decomposed in the presence of aluminum oxide nanoparticles (Al2O3 NPs) catalyst using a fixed bed reactor under an inert atmosphere. Pyrolysis of corncob was carried out in the presence of Al2O3 NPs at different heating rates i.e. 5, 10, 15 and 20°C/min in an oxygen-free atmosphere using TGA technique. Kinetic and thermodynamic studies were performed using the best fit models including Ozawa–Flynn–Wall (OFW), Kissinger–Akahira–Sunose (KAS) and Friedman methods. The average activation energies for Friedman, OFW, KAS were 177.3, 162.9 and 167.8 kJ/mol, respectively for pure corncob and 111.0, 102.5 and 118.06 kJ/mol, respectively for Al2O3-corncob sample. Activation energy was found to be the lowest in the OFW model. Results showed that the presence of Al2O3 NPs catalyst not only reduced pyrolysis temperature and activation energy but also improved the quality of bio-oil.

Physicochemical Characterization, Thermal Behavior, and Pyrolysis Kinetics of Sewage Sludge

Pyrolysis is an energy recovery technique with significant potential for managing wastewater treatment plant byproducts. This research aims to investigate the physicochemical and thermal properties of Moroccan sludge, as well as the behavior of its decomposition during pyrolysis at three different heating speeds (5, 10, and 20 K/min). Characterization of the sludge before pyrolysis through ultimate analysis, proximate analysis, FTIR spectroscopy, and XRD revealed that the sludge consists predominantly of organic matter, with a volatile matter rate of 48%, an ash rate of 37%, and a higher heating value (HHV) of 15 MJ/kg. The TGA-DTG curves identified four distinct stages in the sludge decomposition process: drying, decomposition of organic matter, degradation of calcium carbonate, and decomposition of inorganic matter. Using TG-MS analysis, the principal gases identified during pyrolysis were H2O, H2, CH4, CO2, CO, NO, and SO. The average activation energies (Ea) determined through kinetics models were found to be 413.4 kJ/mol for the Kissinger–Akahira–Sunose (KAS) model, 419.6 kJ/mol for the Flynn–Wall–Ozawa (FWO) model, and 416.3 kJ/mol for the Starink model. The values of Ea and the pre-exponential coefficient (A) obtained through the KAS, FWO, and Starink techniques are consistent with ΔG values ranging between 152 and 155 KJ/mol. The positive ΔS values range from 0.003 to 1.415 kJ/mol.K, indicating the complexity of the sludge response during pyrolysis and the spontaneity of the chemical reaction at high temperatures. The kinetic data obtained serves as a pillar for the development and improvement of sewage sludge pyrolysis systems, reinforcing their role in sustainable energy production.

Kinetic study of pyrolysis of waste polystyrene and polyethylene mixture using novel non‐isothermal method

AbstractA tremendous increase in municipal plastic waste is observed due to high consumption of polymers. With the passage of time the available landfills for discarding of waste plastics decrease whereas, appropriate recycling methods for waste plastics gaining more and more importance. In the present work thermal decomposition of polystyrene (PS) and polyethylene (PE) waste mixture was carried out at different heating rates (5, 10, 15 and 20 °C/min) in a thermogravimetric analyzer (TGA). Thermogravimetric data obtained was further interpreted using new developed non‐isothermal integral method and compared it with several kinetic models i. e., Coats Redfern (CR), Ozawa Flynn Wall (OFW), Kissinger‐Akahira‐Sunose (KAS), Achar and Criado‐Dollimore (CD). The activation energy (Ea) calculated using CR, OFW, KAS, Achar and CD models were found to be in the range of 92.7–130.6, 85.3–120.1, 82.1–113.2, 114.8–162.1 and 95.4–134.4 kJmol−1 respectively, whereas Ea determined by using new developed non‐isothermal method was found to be in the range 70.9 to 106.3 kJmol−1.By comparison the activation energies, it has been concluded that new integral method gave the sharp range and consistent value with highest correlation coefficient, indicating that new developed non‐isothermal method is most suitable for determination of kinetic parameters. The kinetic parameters seem to be very helpful in investigating the reaction mechanism of the solid‐state reactions in real system and will give an opportunity to develop the mechanism of the decomposition reaction.

Kinetic and thermodynamic study of composite with jute fiber as reinforcement

In the present work, engineered by compression molding process via a hydraulic press, the A and B composite samples were carried out with 5% and 10% ratio respectively of Ricinodendron heudelotii oil-based alkyd resin in bio-based matrix made of unsaturated polyester using jute fibers as reinforcement material. The samples’ thermal decomposition was performed through thermogravimetry (TG) and derivative thermogravimetry (DTG) analyses. Both composite samples exhibit two stages of decomposition, where the main occurs at 200 - 550°C. Aiming to study and being able to model the thermal degradation of the elaborated composites, finding the kinetic triplets appears the best option to describe the kinetic process undergo by the composites in order to evaluate the performance application of the composites. Two non-isothermal techniques, Flynn-Wall-Ozawa (FWO) and Kissinger have been used to assess the activation energy Ea, and it is found that the apparent activation energy varies with the degree of conversion indicating that both composites decompose with a multiple step mechanism process. The appropriate reaction model for the second stage of decomposition was best suited with Johnson-Mel-Avrami (n<1) model and has been established, allowing us to model thermal degradation behavior of our elaborated composite material and set predictions. The estimated Arrhenius factor values were respectively about A and B composites, 4.12.1015 min-1 and 10.42.1015 min-1, allowing us to set the final equation characterizing the degradation process for the second and main decomposition stage. Finally, as a result of comparison between A and B composites, A appears to be the more thermally stable due to its lower values of Arrhenius pre-exponential factor over the main stage of decomposition and higher calculated the activation energy values.

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.

AVALIAÇÃO DA DEGRADAÇÃO TÉRMICA DO CAROÇO DE ABACATE RESIDUAL PARA A PRODUÇÃO DE BIOCARVÕES

EVALUATION OF THERMAL DEGRADATION OF RESIDUAL AVOCADO SEED FOR BIOCHAR PRODUCTION. The thermal degradation kinetics of avocado seed biomass (Persea americana) was investigated at the heating rates of 5, 15, 20 and 25 ºC min-1 using thermogravimetric (TGA) and differential thermogravimetric (DTG) analysis techniques in the temperature range from ambient to 780 ºC. Chemical analysis of the avocado seed resulted in: 51.4% cellulose, 42.4% hemicellulose, 20.1% lignin, 2.1% ash, 5.6% extractives. The pyrolysis products were characterized via FTIR, SEM/EDS. The isoconversional methods of Ozawa-Flynn-Wall (OFW) and Kissinger-Akahira-Sunose (KAS) have yielded activation energy, Eα, varying from 36-323 kJ mol-1, respectively. The calorific value of biochars produced in the present study in the range of 265 to 475 ºC was 16,17 to 20,24 MJ kg-1, respectively, which are comparable to those reported values in the literature. Analyzing the DTG simultaneously with the addition of thermal energy, it can be seen that low molecular weight compounds represent the first degradation curves, followed by hemicellulose, cellulose and, lignin. The results obtained in the present work indicate that its feasible to prepare biochars with tunable properties from residual avocado seeds using a slow pyrolysis process, adding commercial value and reducing the environmental impact caused by the inadequate disposal of lignocellulosic materials.

Thermal investigation of NbSe2 nanoparticles synthesized through a temperature-dependent sonochemical method.

Due to their unique size-dependent properties, transition metal di-chalcogenide nanoparticles are trending in research for their potential to revolutionize next-generation electronics, energy storage, and catalytic processes. This study addresses the effect of temperature when synthesizing NbSe2 nanoparticles via the sonochemical method at three different temperatures, room temperature (R.T.), 70 °C, and 100 °C. Energy Dispersive X-ray Analysis (EDAX) confirmed the high purity of NbSe2, with the sample synthesized at 70 °C, displaying the accurate stoichiometric ratio. X-ray diffraction (XRD) analysis revealed that all samples maintained the hexagonal phase of NbSe2, with 70 °C exhibiting superior crystallinity due to their crystallite size, lowest dislocation density, and minimal internal strain. Thermogravimetric analysis (TGA) and differential thermogravimetric (DTG) analyses, demonstrated that the sample synthesized at 70 °C had the highest thermal stability, with the lowest total weight loss and most consistent mass loss behavior. Kinetic parameters were evaluated using the Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods, determining activation energy (E a), pre-exponential factor (A), change in activation enthalpy (ΔH*), change in activation entropy (ΔS*), and Gibbs free energy change (ΔG*). Also, the sample synthesized at 70 °C exhibited the highest E a, indicating superior thermal stability and favorable reaction kinetics. The findings underscore the significant impact of synthesis temperature on the structural and thermal properties of NbSe2 nanoparticles, with the sample synthesized at 70 °C demonstrating optimal characteristics. This study provides valuable insights into temperature-dependent synthesis and the thermal behavior of NbSe2 nanoparticles, highlighting their potential in various technological applications.

Pyrolysis mechanism and pyrolysis kinetics of yellow wine lees.

Yellow wine lees, a by-product produced while brewing yellow wine, can be a helpful biomass resource through pyrolysis. However, there have been very few studies on the pyrolysis of yellow wine lees. The kinetics and mechanism of pyrolysis in yellow wine lees were explored through an extensive study of their chemical and elemental composition. The pyrolysis mechanism of yellow wine lees was further studied using thermogravimetric analysis (TGA) from 30 °C to 900 °C. The TG/DTG analysis showed that yellow wine lees thermally decomposed mainly between 121 °C and 500 °C. The maximum decomposition was observed between 218 °C and 326 °C, with a clear peak at 298 °C. Upon analyzing the 3D-FTIR results, the gas phase products at this stage primarily included inorganic molecules like CO2, H2O, and CH4, along with organic compounds such as esters, alcohols, phenols, amines, ethers, aldehydes, ketones, and acids. The Maillard reaction and ketosis decarboxylation primarily occurred in proteins (amino acids) and carbohydrates. The pyrolysis kinetics of yellow wine lees were analyzed utilizing the distributed activation energy model (DAEM). The results of DAEM were simultaneously verified using the Flynn-Wall-Ozawa (FWO) method. The findings indicated that the pyrolysis of yellow wine lees conforms to the assumptions of infinite parallel reactions and activation energy distribution. As the conversion rate increased during pyrolysis, the activation energy of yellow wine lees initially increased to 210-220 kJ mol-1, then stabilized at 190-200 kJ mol-1 and rapidly decreased to approximately 100 kJ mol-1. This study offers a theoretical basis for the application of yellow wine lees using pyrolysis.

Research on the characteristics of pressured pyrolysis products of marine plastics

The problem of marine plastic pollution, mainly composed of polyolefin plastics, is becoming increasingly serious, and reducing marine plastic pollution is urgent. Pyrolysis, as a promising technology for treating polyolefin plastics such as polystyrene (PS), has great potential in addressing marine plastic pollution issues. In order to explore the possibility of resource utilization of marine plastics, this article studied the effect of pressure changes on the pyrolysis products of marine plastics. Marine PS was prepared by soaking routine PS in artificial seawater and air drying, and the most significant difference between the two was found to be the salt attached to the surface. The dynamic characteristics of marine PS were analyzed using Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods, and the apparent activation energy of marine PS calculated by FWO and KAS methods are 102.94 kJ·mol−1 and 95.76 kJ·mol−1, respectively. The effect of pressure at different temperatures on the pyrolysis products of marine PS was studied. The results indicate that the yield of pyrolysis oil decreases as the pressure is increased, while solid products are obtained from scratch. The increase in pressure will gradually make the composition of the thermolytic gas become monotonous. Under critical pressure, pressurization promotes an increase in CH4 content while reducing H2 content, causing the lower heating value of pyrolysis gas to increase to 4.355 kJ·g−1. Analysis of oil content found that increasing pressure promotes the growth of Benzene Toluene Ethylbenzene & Xylene (BTEX) to 33.61%, but excessive pressure can significantly reduce the higher heating value from 42.116 MJ·kg−1 to 31.825 MJ·kg−1. The solid products were characterized using FTIR and it was found that pressure did not have a significant impact on surface functional groups. Increasing the pressure properly promotes the agglomeration of amorphous carbon.

Co-pyrolysis of thermoplastic polyurethane with paulownia wood: Synergistic effects on product properties and kinetics

Co-pyrolysis of plastics and biomass offers an effective approach for waste disposal. In this study, the synergistic effects during the co-pyrolysis of thermoplastic polyurethane (TPU) and paulownia wood (PAW) were investigated in terms of pyrolysis kinetics and product properties using tube furnace, TG-FTIR and GC/MS. The results revealed that co-pyrolysis promoted the material pyrolysis and facilitated the pyrolysis process taking place at low temperatures. By adopting the Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO) and Starink methods, the average activation energies of pure TPU, PAW, and TPU/PAW blends with a 1:1 mass ratio were determined to be 139 kJ/mol, 288 kJ/mol, and 126 kJ/mol. It is indicated that co-pyrolysis significantly reduced the activation energies and enhanced reactivity. Tube furnace experiments demonstrated that TPU/PAW blend with 1:1 mass ratio exhibited the highest synergism. The TPU melt acted as a physical barrier, leading to increased production of char and oil, and lower production of volatile gas. In the pyrolysis oil, the synergistic effect effectively hindered a formation of alcohol phenols. In the meanwhile, the synergistic effect also boosted generations of aliphatic compounds and ketones, increasing the heat value use of pyrolysis oil. Furthermore, a reaction pathway and mechanism of co-pyrolysis of TPU and PAW was proposed. The active molecules and free radicals generated by the pyrolysis of PAW promote the hydrogen transfer cyclization of polyester polyols decomposed by TPU, and the hydrogen free radicals released by TPU promote the depolymerization and activation of PAW. Moreover, the catalytic effect of alkali metal elements in PAW promotes the synergistic effect. The results of the study provide a basis for the co-pyrolysis of waste plastics and biomass to achieve high value utilization of waste.

The influence of B doping on phase formation and microstructural evolution in NHL during solid-state reactions

Natural Hydraulic Lime (NHL), was synthesized by doping B2O3 into calcium carbonate and silica aerogel. By introducing varying levels of B3+ ion doping (0/1/5/10/15/20/25 mol%), a range of NHL compositions were successfully prepared, thereby enabling regulation of the NHL phase composition. Furthermore, through the doping of 25 mol% B3+ ions, in-depth investigations employing XRD, SEM, and FT-IR were conducted to explore phase transitions and ion migration during NHL calcination at different temperatures. Thermal analysis kinetics studies further revealed the variation of activation energies for CaCO3 decomposition and C2S crystallization with changing levels of B3+ ion doping. The introduction of B ions was observed to stabilize the α’ phase of dicalcium silicate (C2S) and moderately enhance the reactivity of calcium oxide (CaO). B3+ ions significantly influenced the crystallization mechanism of C2S, shifting it from a diffusion-controlled process to a heterogeneous nucleation process. The application of the Kissinger and Flynn-Wall-Ozawa (FWO) methods assisted in elucidating the underlying reasons for these differences. Both approaches demonstrated a substantial decrease in activation energy, signifying the pronounced influence of B doping on the sintering regime and phase transition mechanism of NHL. In summary, the precise modulation of NHL phase composition and sintering regime was achieved through B doping. These findings not only deepen our understanding of the mechanistic role of B3+ ions in NHL preparation and application but also offer robust guidance for the production process of NHL.

Research on the Combustion Performance of Municipal Solid Waste in Different Sorting Scenarios: Thermokinetics Investigation via TG-DSC-FTIR-MS.

Waste sorting is regarded as one of the most important strategies for municipal solid waste (MSW) management. The changes in the combustion parameters after MSW sorting had a significant impact on the actual operation of the boiler. In the present study, the effects of heating rate on combustion characteristics and dynamics of MSW in different sorting scenarios were studied using the thermogravimetry (TG)-differential scanning calorimetry (DSC)-Fourier transform infrared (FTIR)-mass spectrometry (MS) technique. TG-DSC analysis showed that the heat released from MSW combustion at different heating rates ranged from 1394.1 to 4130.1 J/g. According to the TG-DTG curves, the combustibility of 30% sorted MSW was increased by 1.2 times compared to that of the unsorted scenario. In the 30% sorted scenario, the average activation energies were estimated to be 161.24 and 159.93 kJ/mol based on the Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods, respectively. Based on the Coats-Redfern (CR) method, the minimum activation energies for unsorted and 20% sorted scenarios were 148.74 and 135.53 kJ/mol at 523 to 606 K, respectively, while they were 29.42 and 33.22 kJ/mol at 606 to 780 K. XRF analysis showed that the alkali and alkaline earth metal oxides in the ash contributed to a high risk of slagging and scaling. This work can provide a scientific basis for the real situation of MSW incineration.

Thermal degradation kinetics, thermodynamics and pyrolysis behaviour of polycarbonate by TGA and Py-GC/MS

This paper elucidates the thermal and catalytic (mordenite and y-zeolite) pyrolysis characteristics of Polycarbonate (PC) as well the kinetics and thermodynamic parameters of the thermal decomposition of PC. Three distinct isoconversional methods, namely the Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), and Starkin methods, were employed to evaluate the kinetic and thermodynamic parameters. The average activation energies determined with the KAS, FWO, and Starink methods were 245.81, 235.36, and 249.99 kJ/mol respectively, and they were reduced by 17 % and 21 % when mordenite and y-zeolite were utilized as catalysts, respectively, according to the calculations performed with the KAS method. Py-GC/MS analyses showed that phenolic components were found to be dominant in the oil product obtained under non-catalytic conditions. Micropores in the structure of y-zeolite constitute 54.4 % of the total surface area, while micropores in the structure of mordenite constitute 95.5 % of the total surface area. Depending on the structure of the catalysts used, phenolic components decreased slightly, and aromatic and PAH (Polycyclic Aromatic Hydrocarbons) components replaced these components. As a result, phenolic compounds in the oil product obtained with y-zeolite (56.7 %) were less than those produced with mordenite (61.02 %). PAHs were 12.9 % and 7.5 % in the presence of y-zeolite and mordenite, respectively. Thus, the results evidence the molecular size of zeolite catalysts, as well as their acidic structure, which are crucial factors in the conversion of phenolic compounds.

Effect of sludge-based suppression materials on the explosive flame characteristics of aluminium dust

A study was conducted to investigate the inhibitory effect of sludge-based phosphate-containing composite powder explosion suppressants (MPP/AMS) on aluminium dust explosion and combustion. The experiment compared the inhibition characteristics of ordinary sewage sludge particles, high-temperature alkali-modified sludge particles, phosphate-containing particles, and phosphate-modified sludge particles. The study utilized a flame propagation experimental device and an explosion pressure testing device for comprehensive research. The experimental recording devices revealed that sludge-based composite powder explosion suppressants effectively inhibit aluminium powder explosion and combustion. Thermodynamic analysis of the rapid oxidation stage was performed using the Coats Redfern (C-R) method, and validation was conducted using the Flynn Wall Ozawa (FWO) and Kissinger Akahira Sunose (KAS) methods. The results theoretically explain that sludge-based composite powder explosion suppressants can effectively suppress aluminium powder explosions and exhibit a blocking effect. Surface morphology and material element characterization experiments were conducted before and after the explosion, combined with pyrolysis characteristics. The analysis demonstrated that the inhibition mechanism of sludge-based composite powder explosion suppressants on aluminium powder explosion primarily involves two aspects: physical inhibition (MPP coating inhibition, porous adsorption isolation) and chemical inhibition (decomposition heat absorption, product oxidation). The theoretical findings provide evidence of the superior inhibitory effects of sludge-based composite powder explosion suppressants, offering new insights for the resource utilization of sludge waste and the development of novel explosion suppression materials.

Original Synthesis of Ethylene‐Acrylic Acid (ester) Copolymers Derivatives from 5‐substituted Cyclooctenes with A Controllable Way Via Ring‐Opening Metathesis Polymerization

AbstractHigh‐value grades of ethylene‐acrylic acid (EAA) and ethylene‐acrylic ester copolymers have been producing produced from ethylene, acrylic acid (AA), and the alcohol derivative via radical reaction in autoclave reactor at a temperature of 150‒230 °C and pressure of 150–300 MPa. In this paper, EAA and its ester derivatives are originally created from the 5‐substituted cyclooctenes (COE) with side chains of carboxylic acid or ester derivatives by ring‐opening metathesis polymerization (ROMP) at normal temperature and pressure. Especially, the controllable insertion of side chain is effectively achieved by altering the molar ratio of COE and 5‐substituted COE. Furthermore, the polar carboxyl groups (ester groups) have a detrimental effect on the order assigns of the linear backbone and thus hindered crystallization, indicating relatively lower crystallizing and melting temperature with an increase in the content of side chain. As the amounts of polar groups raised, the stiffness of chain segments enhanced, thereby leading to an elevation in the copolymer's energy storage modulus (E') and glass transition temperature (Tg). Moreover, the Flynn‐Wall‐Ozawa (FWO) technique is employed to characterize and fit the non‐isothermal crosslinking kinetics of the ethylene‐acrylic ester derivatives, and the crosslinking activation energy is determined to lie between 97 and 140 kJ mol−1.

Application of used engine oil as a hydrogen-rich substance in co-pyrolysis with pine wood for reduction its environmental hazards and produced diesel-like fuel: Thermal behavior, kinetic and thermodynamic analysis

This study introduced co-pyrolysis process as effective way for convert used engine oil (UEO) into useful product and reduced its environmentally hazardous. The co-pyrolysis of acid-washed pine wood (APW) and used engine oil was investigated through thermogravimetric analysis (TGA) within the temperature range of 30 to 700 °C, employing heating rates of 5, 10, and 20 °C/min. Among the blends studied, a blend containing an equal ratio of two feeds exhibited the highest synergism. The study of the oil composition obtained from the co-pyrolysis of APW and UEO in the fixed-bed reactor showed that the simultaneous use of UEO as a feedstock reduced the yield of oxygenated compounds from 82.69 % to 25.06 %, while significantly increasing the yield of hydrocarbons from 17.31 % to 74.93 % compared to APW alone. 51.25 % of these hydrocarbons were in the range of diesel fuel. The kinetic parameters were determined using three iso-conversional methods: Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (OFW), and Starink. The obtained average activation energy was 162.65, 161.39, and 161.66 kJ/mol for FWO, KAS, and Starink, respectively. The pre-exponential factors, determined by the Kissinger method, varied from 1.98 × 108 to 9.12 × 1018. Also, the use of master plots in combination with iso-conversional methods showed that the reaction order model, f(α)= (1-α)n, with n between 2 and 3, provides the best description for the co-pyrolysis of APW and UEO in the applied heating rate range. Furthermore, with increasing conversion from 0.2 to 0.8, the thermodynamic parameters including ΔH, ΔG, and ΔS, changed in the range of 125.09–234.59 KJ/mol, 159.02–155.92 KJ/mol, and −0.06 to 0.13 KJ/mol, respectively.

The utilisation of thermally treated poultry farm waste for energy recovery and soil application

The thermal treatment was analysed of poultry farm waste, excrement and litter, and their mixture. Two thermal treatment methods were chosen: Torrefaction at 300 °C and hydrothermal carbonisation (HTC) at 250 °C. The characterisation of raw materials and solid products was performed by proximate and ultimate analysis, and analysis of the high heating value. Thermogravimetric analysis (TGA) was performed of the combustion of raw materials and solid products in an air atmosphere. The kinetic and thermodynamic parameters were determined according to the Flynn–Wall–Ozawa (FWO) kinetic model. The contents of total organic carbon, chemical oxygen demand, total nitrogen and total phosphorus, as well as the content of total phenols, were determined in the process fluids. In addition, a germination test was performed with garden cress.The results show that the torrefied biomass had a higher carbon (C) content and a higher calorific value than raw biomass. The FWO kinetic model proved to be suitable for describing the kinetic of combustion of the tested samples' high fitting coefficients. The Eα for torrefied litter, excrement and their mixture ranged between 129 and 338, 108–550 and 136–489 kJ/mol, while for the HTC-treated samples generally lower Eα values were measured, 187–364, 121–229 and 126–428 kJ/mol, respectively. Germination tests with garden cress and analysis of nutrients showed that the tested products of torrefaction and HTC have a perspective for agricultural use at a sample concentration of up to 10 wt% in the substrate.