Distribution Of Activation Energies Research Articles

Unlocking biosolid pyrolysis: Towards tailored biochar with different surface properties

To develop a thorough understanding of the thermal decomposition process of biosolids and the qualities of biosolid-derived biochar, this study performs a thermogravimetric analysis (TGA) of biosolids and examines the properties of biosolid-derived biochar produced from varying temperatures of pyrolysis. The pyrolysis of biosolid is conducted under varying heating rates (10, 15, 20 and 25 °C/min) until reaching the maximum temperature of 900 °C. The kinetic triplet (kinetic model, activation energy, and frequency factor) at the corresponding conversion point is determined by analysing the TGA results of the biosolids. The thermal degradation of hydrated compounds shows activation energies ranging from 80 to 100 kJ/mol, whereas the thermal decomposition of organic matter in biosolids exhibits activation energies ranging from 120 to 497 kJ/mol. As the temperature increases, the thermal reactions transition from simple surface reactions with frequency factors below 109 s-1 to more complex reactions with frequency factors above 109 s-1. The distributed activation energy model (DAEM) is established using the approximated temperature function and the activation energy distribution functions. The DAEM shows the mean activation energies of 93–128 kJ/mol, 279–287 kJ/mol and 359–377 kJ/mol for activation energy distribution peaks. The standard deviations of the mean activation energies are 30–64 kJ/mol, 23–30 kJ/mol and 23–41 kJ/mol, respectively. As the pyrolysis temperature is raised from 700 °C to 900 °C, both the specific surface area and micropore volume of biosolid-derived biochar increase, from 48.25 m2/g to 65.74 m2/g and 0.0313 cm3/g to 0.0369 cm3/g, respectively. The findings of this study demonstrate biosolid pyrolysis kinetics, which is essential for establishing a pyrolysis facility for biosolid management and producing biosolid-derived biochar with varying qualities.

Non‐isothermal Thermogravimetric Analysis of Peltophorum pterocarpum and Evaluation of Kinetic Triplet

AbstractThe primary focus of the twenty‐first century has been on developing new and cleaner fuels from renewable sources. The increasing availability of renewable energy sources in environment, such as lignocellulosic biomass derived from agricultural and forest residues, has created a plethora of opportunities for biofuel production. For this purpose, the search for appropriate waste biomass source and the design of suitable reactors are very essential, where the latter requires the knowledge of kinetic triplets. These requirements paved the way to the novelty of the present work as a selection of a rarely used biomass source, that is, Peltophorum pterocarpum, and its non‐isothermal thermogravimetric analysis for the evaluation of kinetic triplet of the process. The range of temperature is 298–1173 K attained at heating rates of 10–55 K min−1. Kinetics were estimated using differential Friedman method (DFM), distributed activation energy method (DAEM), Ozawa–Flynn–Wall (OFW), Kissinger–Akahira–Sunose (KAS), and Starink (STK) models. Mean activation energy (kJ mol−1) and pre‐exponential factor (min−1) of pyrolysis process by five models were 183.68 and 1.24 × 1017 for DAEM, 194.28 and 3.08 × 1021 for DFM, 183.68 and 4.40 × 1016 for KAS, 184.12 and 2.12 × 1014 for OFW, and 183.93 and 3.56 × 1016 for STK. Average values of changes in Gibbs free energy, enthalpy, and entropy by five models are 174 kJ mol−1, 178 kJ mol−1, and 0.007 kJ mol−1 K−1, respectively. Criado's master plots revealed distinct reaction pathways during the process for different conversion levels.

Demineralization effects on physicochemical and combustion characteristics of biomass: Insights into distributed kinetics, flue gas evolution, and slag formation

Biomass as the only carbon-bearing renewable energy has enormous potential to challenge the established energy structure dominated by fossil resources, and incineration technology is one of the most direct and efficient pathways for utilizing biomass resources, unfortunately enduring the inevitable sintering and slagging problems owing to the excessive alkali metals. Herein, we comparatively investigated the effects of five leaching solvents (water, acetic acid, wood vinegar, hydrochloric acid, and oxalic acid) on the physicochemical properties and ash-removal capabilities of wheat straw (WS) and rice husk (RH), with a view to achieving better performance in the subsequent combustion characteristics, kinetic examination, flue gas, and slag evolution. Results indicated with ionization ability increased (water < acetic acid < hydrochloric acid), the WS exhibited a strong demineralization performance (maximum 61.1%), further leading to a steep weight loss in its combustion characteristic curve at approximately 350 °C and a delayed peak temperature after the removal of alkali metal. Multiple distributed activation energy model and sensitivity analysis revealed that leaching pretreatment enhanced the activation energy (189–191.8 kJ mol−1) and optimized energy distribution at the preliminary stage of the combustion reaction. In addition, the absence of alkali metals suppressed the catalytic oxidation reaction in the flue gas, remarkably limiting the formation of CO2 but facilitating the release of CO and CH4. Meanwhile, a considerable optimal in biomass ash slagging, in which the initial temperature of the liquid phase slag for WS ash increased to 991 °C. Notably, HCl showed the strongest demineralization performance among the five leaching solvents during pretreatment, but the high-temperature slag content was still higher than that of acetic acid. Therefore, slagging performance is not only associated with the demineralization ability of leaching solvents, but also with ash composition.

KINETICS AND THERMODYNAMIC ASSESSMENT OF RICE HUSK IN AN INERT ATMOSPHERE AS A FEEDSTOCK FOR ALTERNATIVE FUEL PRODUCTION

The utilisation of rice husk as a feedstock for alternative fuel production is an area of growing interest due to its abundance and potential as a renewable energy source. This study reports investigation of kinetics and thermodynamics of rice husk pyrolysis in an inert atmosphere. Experimental analysis, including proximate, ultimate, structural composition and thermogravimetric analyses (TGA), were conducted to determine the proxanal, ultanal, chemical composition and pyrolysis characteristics of rice husk under inert conditions. Kinetics of the pyrolysis process was evaluated using distributed activation energy model (DAEM) while thermodynamic parameters such as activation energy (E A), changes in enthalpy (ΔH), entropy (ΔS),and Gibbs free energy (ΔG) were computed to provide insights into the reaction mechanisms. The feedstock exhibited ash content, fixed carbon, volatile matter, and higher heating value on dry basis of 13.56wt%, 16.37wt%, 70.07wt% and 15.22MJ/kg respectively while the result of ultimate analysis showed carbon, hydrogen, nitrogen, sulphur and oxygen content of 40.95, 5.67, 0.22, 0.09 and 52.17wt%. The chemical composition result (water extractives-free) indicated cellulose, hemicellulos and lignin content of 39.12, 17.56 and 22.43 wt%. The kinetics analysis revealed that the pyrolysis process followed a single-order reaction mechanism and irreversible, suggesting that the pyrolysis reactions proceed in a direction that favors the formation of products. The average E A, ΔH, ΔS and ΔG required for the pyrolysis reactions was established to be 140.56 kJ/mol, 137.00 kJ/mol, -135.25 J/mol and 222.38 kJ/mol respectively. The comprehensive assessment of the feedstock affirms its suitability for alternative fuel production towards a greener energy landscape.

Distributed activation energy treatment of polyimide aerogel and its blocking effect on thermal runaway propagation of ternary battery

The thermal runaway of lithium batteries has become an urgent problem that needs to be solved today. In this study, polyimide aerogel materials with high temperature resistance and low thermal conductivity were prepared by supercritical drying equipment. Firstly, the activation energy distribution of the two pseudo-components of polyimide aerogels was calculated by TGA data at different heating rates, and then the optimal kinetic parameters were obtained. Secondly, a series of experiments were designed to study the blocking effect of polyimide aerogel films with different thicknesses (0.5 mm, 1 mm, 1.5 mm, and 2 mm) on the uncontrolled transmission of batteries, which showed that 2 mm film could successfully block the uncontrolled transmission of battery heat at 711.9 °C. 0.5 mm, 1 mm and 1.5 mm polyimide aerogel films can delay the thermal runaway of the battery, and the delay time was 182 s, 224 s and 259 s respectively. At the same time, the indicator gas was detected and analyzed, indicating that the barrier material can effectively reduce the content of CO2 gas and heat release rate. This study provides new enlightenment for the development of polyimide aerogels, and new ideas for the thermal insulation design of batteries.

Withdrawn: Co-hydropyrolysis of sewage sludge and algae biomass: A systematic study on thermal decomposition behaviors and kinetic characteristics

In the present study, a thermogravimetric analyzer was used to assess the co-hydropyrolysis kinetics of sewage sludge and algae biomass. Three isoconversional methods (Kissinger-Akahira-Sunose, Flynn-Wall-Ozawa, and Friedman) and one model-fitting method (DAEM) accurately fitted the experimental data at three heating rates (10, 30 and 50 °C/min) between 10 % and 90 % conversion. These methods agree with the trends shown by the activation energy (Ea) distribution calculated, with fluctuations between 120 and 330 kJ/mol. Compared with the pyrolysis of a single sample, the reaction activation energy of sludge and algae was significantly reduced in the case of co-pyrolysis. When 20 % algae are added, the activation energy is only 50 % of the original, below 100KJ/mol. Physiochemical characterization confirmed that they have the potential for fuel and energy production. Kinetic parameters fitted by DAEM were successfully verified at the highest heating rate studied and the linear fitting curve of DAEM is better. The kinetic results confirm that the activation energy is related to the conversion rate, and the change of activation energy and conversion rate indicates that the biomass undergoes a very complex pyrolysis process. In this study, the mixing of sewage sludge and algal biomass in hydrogen atmosphere can significantly change the energy required for pyrolysis reaction, which provides data support for the development, design and optimization of pyrolysis reactors. According to the change of weight loss and activation energy, it provides support for the feed amount, reaction temperature and gas flow of the pyrolysis furnace in the process of pyrolysis reaction.

Comprehensive investigation of almond shells pyrolysis using advance predictive models

This research focused on comprehensive characterization and assessment of almond shells pyrolysis for bioenergy potential through thermogravimetric analysis from ambient temperature to 900 °C at different heating rates of 10, 15, and 20 °C/min in inert environment. Iso-conversional model-free methods like Friedman, Ozawa-Flynn-Wall (OFW), and Kissinger-Akahira-Sunose (KAS) were used for kinetic analysis. Average activation energies (Ea) evaluated using Friedman, OFW, and KAS methods were 198.45 kJ mol−1, 204.43 kJ mol−1, and 204.97 kJ mol−1, respectively. The evaluation of thermodynamic parameters, including ΔH‡, ΔG‡, and ΔS‡, was also assessed. The average values of ΔH‡, ΔG‡, and ΔS‡, were found to be 199.4 kJ mol−1, 172.17 kJ mol−1 and 42.60 kJ mol−1 respectively. The reaction mechanism was obtained from combined kinetics. A high R2 value of 0.9933 demonstrates strong agreement between the combined kinetic analysis results and the experimental data. The distribution activation energy model was assessed employing four pseudo elements identified as PC1, PC2, PC3, and PC4. Artificial Neural Network (ANN) and Boosting regression trees (BRT) were used for the prediction of Ea of almond shells pyrolysis. The detailed understanding of thermokinetics and creating customized predictive and innovative modelling techniques like ANN and BRT sets a new benchmark for developing customized models for thermochemical conversion of varieties of almond shells.

Lifespan prediction procedure of volume nanogratings imprinted by femtosecond laser in optical glasses

Volume nanogratings imprinted by infrared femtosecond laser in oxide glasses exhibit a characteristic birefringent signature, which translates into measurable retardance. Upon thermal annealing, such signature is progressively erased, typical of nanograting erasure. In this work, we propose a procedure to predict the lifespan of nanogratings by two main approaches: 1/ numerical modeling of optical retardance ageing using the Rayleigh-Plesset equation, and 2/exploiting VAREPA (VAriable REaction PAthways) framework fed by simulated ageing data. By considering experimental time – temperature annealing conditions, the modeled retardance is gathered as a function of demarcation energy to build a so-called Master Curve and then compared to accelerated ageing experiments. The erasure constant rate k0 can be determined for 8 commercial optical glasses. Based on a distributed Rayleigh-Plesset model, k0 and activation energy distribution are linked to glass viscosity and its temperature dependency. Finally, we discussed the restrictions on VAREPA application for an accurate lifetime prediction. This work provides guidelines for the future development of nanogratings based devices and applications, including optical data storage, birefringent devices, and optical sensors, through a judicious choice of glass composition and associated properties.

Comprehensive kinetic modeling and product distribution for pyrolysis of pulp and paper mill sludge

Pyrolysis holds immense potential for clean treatment of pulp and paper mill sludge (PPMS), enabling efficient energy and chemical recovery. However, current understanding of PPMS pyrolysis kinetics and product characteristics remains incomplete. This study conducted detailed modeling of pyrolysis kinetics for two typical PPMSs from a wastepaper pulp and paper mill, namely, deinking sludge (PPMS-DS) and sewage sludge (PPMS-SS), and analyzed comprehensively pyrolysis products. The results show that apparent activation energy of PPMS-DS (169.25–226.82 kJ/mol) and PPMS-SS (189.29–411.21 kJ/mol) pyrolysis undergoes significant change, with numerous parallel reactions present. A distributed activation energy model with dual logistic distributions proves to be suitable for modeling thermal decomposition kinetics of both PPMS-DS and PPMS-SS, with coefficient of determination >0.999 and relative root mean square error <1.99 %. High temperature promotes decomposition of solid organic materials in PPMS, and maximum tar yield for both PPMS-DS (53.90 wt%, daf) and PPMS-SS (56.48 wt%, daf) is achieved at around 500 °C. Higher levels of styrene (24.45 % for PPMS-DS and 14.71 % for PPMS-SS) and ethylbenzene (8.61 % for PPMS-DS and 8.33 % for PPMS-SS) are detected in tar and could be used as chemicals. This work shows great potential to propel development of PPMS pyrolysis technology, enabling green and sustainable production in pulp and paper industry.

Hydrochars derived via wet torrefaction of empty fruit bunches: Effect of temperature and time, comparison to oil palm trunks counterpart, and their pyrolysis behavior

In this study, hydrochars derived from the wet torrefaction of empty fruit bunches (EFB) were characterized and compared to those of oil palm trunks (OPT). Then, the kinetics modelling of EFB-derived hydrochars was evaluated and compared with the Distributed Activation Energy Model (DAEM) under logistics distribution via thermogravimetric analysis (TGA) under pyrolytic conditions at different heating rates. Bench-scale pyrolysis of EFB-derived hydrochars were also performed and characterized. This study elucidates the effect of prolonged residence time (3–72 hours) at different temperatures (180–220 °C) on the wet torrefaction of EFB, and comparison to OPT provides an understanding of wet torrefaction mechanisms. The pyrolysis kinetics of EFB-derived hydrochars provide insights into their pyrolysis behavior and their potential in pyrolytic application. Increased temperature and residence time enhanced the higher heating value (HHV) of the hydrochars at the expense of low mass yield. Hydrochars obtained at 220 °C and 72 hours had the highest HHV at 27.4 ± 0.5 MJ kg−1 with a mass yield of 38.3 ± 2 wt%. EFB-derived hydrochars had a higher mass yield than OPT-derived hydrochars. The van Krevelen diagram revealed that dehydration was the primary reaction pathway for EFB and OPT-derived hydrochars. SEM showed the formation of secondary deposits on both EFB and OPT hydrochars. EFB-derived hydrochars obtained at 220 °C and 72 hours had the highest mean activation energy (E0) with a distribution of activation energy (σ) from 176.7 to 181.7 kJ mol−1 and 43.4–49.9 kJ mol−1, respectively. The increased mean and distribution of activation energies were attributed to the lignin-dense structure of the hydrochars. The kinetic parameters of the hydrochars were also independent of heating rates at low heating rates (< 20 °C min−1). The thermal stability of the pyrochars obtained from EFB-derived hydrochars enabled their applications in fields such as carbon support, activated carbon, water purification process, or carbon sequestration.

Comparative investigation of low temperature oxidized and pyrolyzed cokes from the inferior heavy oil: Structural feather, thermo-oxidation behavior, and kinetics

It was crucial to study the low temperature coking process for the heavy oil, which affected the fuel availability and subsequent in-situ combustion progress. From this perspective, low temperature coking experiments with different atmospheres were accomplished for the inferior heavy oil to obtain oxidized (cokeLTO) and pyrolytic (cokeLTP) cokes, which were further employed to trace structural feathers via joint analysis of elemental analysis, Fourier transform infrared spectrophotometry (FTIR) and X-ray photoelectron spectroscopy (XPS) spectra, and to characterize thermo-oxidative characteristics and kinetics via different thermal analyses (TG-DTG/DSC) and model-free methods. The results showed that a relatively less aliphatic and more aromatic structures were contained in cokeLTO with a relatively higher proportion of C-O, C = O, O-C = O groups and C/H ratio, implying that oxygen atom was served as the promoter to replace hydrogen atom and accelerate macromolecular structure formation. While the decomposition and conversion of N- and S- functional groups were complicated and insensitive to the coking atmosphere. Furthermore, cokeLTO had a more dominant thermo-oxidation behavior than cokeLTP with better exothermic characteristic and lower activation energy distribution. From this study, it could provide a vital piece of updated insights on the role of low temperature oxidation process in coke deposition and feature.

Heat and mass transfer analysis of coal coking process in the coking chamber

ABSTRACT To study the coking heat mass transfer process and reveal the law of industrial-scale coal pyrolysis, the heat transfer characteristics of coal material in the coking process are analyzed based on coke oven temperature measurement experiments. A mathematical model of the coking process in the coking chamber was constructed based on the distributed activation energy model. The heat transfer process of the coal feed, generation of coke oven gas, and dynamic precipitation characteristics of each component during the coking cycle were further studied. The results show that tar and water are the earliest released and fastest precipitated pyrolysis products, respectively, which are completely precipitated at 800 K. The contents of the components of the inward and outward gases are obviously different, with CH4 and H2 accounting for 73.79% of the outward gas, while H2O and tar account for 77.80% of the inward gas. When the coal reaches 1200 K, all pyrolysis products except H2 are precipitated completely. The model can effectively predict the changes of raw coke oven gas composition during the coking process at different locations in the coking chamber.

Investigation of the evolved pyrolytic products and energy potential of Bagasse: experimental, kinetic, thermodynamic and boosted regression trees analysis

This study explored bagasse's energy potential grown using treated industrial wastewater through various analyses, experimental, kinetic, thermodynamic, and machine learning boosted regression tree methods. Thermogravimetry was employed to determine thermal degradation characteristics, varying the heating rate from 10 to 30 °C/min. The primary pyrolysis products from bagasse are H2, CH4, H2O, CO2, and hydrocarbons. Kinetic parameters were estimated using three model-free methods, yielding activation energies of approximately 245.98 kJ mol−1, 247.58 kJ mol−1, and 244.69 kJ mol−1. Thermodynamic parameters demonstrated the feasibility and reactivity of pyrolysis with ΔH ≈ 240.72 kJ mol−1, ΔG ≈ 162.87 kJ mol−1, and ΔS ≈ 165.35 J mol−1 K-1. The distribution of activation energy was analyzed using the multiple distributed activation energy model. Lastly, boosted regression trees predicted thermal degradation successfully, with an R2 of 0.9943. Therefore, bagasse's potential as an eco-friendly alternative to fossil fuels promotes waste utilization and carbon footprint reduction.

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.

Kinetic Characteristics of Kerogens in the Kuonamka Complex, Lower and Middle Cambrian of the Siberian Platform

Abstract —The kinetic characteristics of kerogen (activation energy and frequency factor distributions of the initial generative potential) determine the dynamics of naphthide generation during catagenesis. In the previous studies on quantitative modeling of naphthidogenesis in the Kuonamka source rocks, the kinetic characteristics were taken by analogy with the known kerogens from other complexes and provinces. It seems relevant to determine the effective kinetic characteristics of the kerogen from the Kuonamka source rocks from experimental data. To estimate the kinetic parameters, specialized multi-rate pyrolysis studies were performed. The variations in pyrolysis data was reported to be presumably associated with the conditions of kerogen and source rock formation during accumulation and diagenesis of organic matter. The effect of carbonate and organic carbon contents on the temperature range of the second pyrolysis peak is recorded. Reconstruction of the average (effective) kinetic characteristics of kerogens from the Kuonamka source rock, was conducted using data on kerogens from Serkinsky-5 and 10 and Tit-Ebya-6 wells, which are less degraded than kerogens from Ust’-Maiskaya-366 well and probably attained the early mesocatagenesis grades. The current average effective kinetic characteristics of kerogen were estimated and corrected for the possible partial degradation of reference samples. The obtained effective kinetic models of kerogen are compared with models of kerogens of various genetic types known from the literature. The estimated effective kinetic characteristics of kerogens or Menil-1 and Type B kerogens with similar characteristics are to be taken, as a first approximation, in regional historical-genetic (basin) modeling of naphthide generation in the Kuonamka source rock.

Thermal oxidation characteristics of polystyrene with different particle sizes based on the traditional kinetic approaches and distributed activation energy model

Thermal oxidation characteristics of polystyrene with different particle sizes based on the traditional kinetic approaches and distributed activation energy model

The implication of kinetics characteristics of modern organisms for the hydrocarbon generation evolution of organic matter components in the lacustrine source rocks: A case study of the Dongying Formation from the Bozhong Sag, Bohai Bay Basin

The hydrocarbon generation evolution characteristics of lacustrine source rocks are crucial for understanding hydrocarbon resources. In this research, we focus on the mudstone found in the third member of the Paleogene Dongying Formation (E3d3) within the Bozhong Sag of the Bohai Bay Basin as a case study. An analysis of the discrepancy in geochemical characteristics and kinetic parameters was carried out by utilizing the modern organisms (pine pollen and benthic algae) analogies to the organic matter (OM) components (Pinaceae sporopollen and benthic algae amorphous). Furthermore, the bulk hydrocarbon evolution of the Dongying Formation mudstones was further discussed in combination with a water-added sealing thermal simulation experiment and basin simulation. Our findings indicate that the pine pollen and benthic algae have higher OM abundance compared to the E3d3 mudstones, and their OM types are both Ⅱ1-Ⅱ2, which possess excellent potential for oil generation. In contrast, the E3d3 mudstones are predominantly in the low mature to mature thermal evolution stage. When we compare hydrocarbon generation rates and transformation ratios using Rock-Eval pyrolysis, it becomes evident that modern organisms are more prone to generate large amounts of hydrocarbons even at a low mature stage. The kinetic parameters of pine pollen are notably higher compared to those of benthic algae and the E3d3 mudstone samples. In parallel first-order reactions, the activation energy obtained by the single-frequency factor model (SFFP model) displays a narrow distribution range, while the activation energy distribution range of the multi-frequency factor model (MFFP model) is broader. The MFFP model focuses more on the variations of hydrocarbon kinetic parameters throughout the entire process, which is more in conformity with the actual geological process. The enclosed thermal simulation experiment and basin simulation analysis unveil the presence of two distinct phases of hydrocarbon generation within the Dongying Formation. Furthermore, it becomes evident that abundant benthic algae and Pinaceae sporopollen components play vital roles in both of these phases. In conclusion, the method of applying modern organisms to analogize the hydrocarbon generation evolution characteristics of the parent components of lacustrine source rocks seems feasible. Meanwhile, the Dongying Formation in the Bozhong Sag also possesses broad exploration prospects for hydrocarbon resources.

Valorization of waste PET: Understanding the role of active ammonia in facilitating PET depolymerization and aromatic nitrile formation

Realizing the recovery and valorization of waste polyethylene terephthalate (PET) plastics into value-added products have gained significant importance. This study successfully synthesized aromatic nitriles, specifically terephthalonitrile (TPN), from waste polyethylene terephthalate (PET) plastic through in situ catalytic pyrolysis with urea and γ-Al2O3 catalyst. Based on distributed activation energy model, positive interaction between waste PET and urea is responsible for improved thermal decomposition kinetics. The dosage of urea and pyrolysis temperature significantly influenced TPN production. TPN yield reached 32.5% with ca. selectivity of 85% at 550 °C and equivalent urea dosage. Density functional theory calculations validated the role of active ammonia in reducing energy barriers and thus facilitating PET depolymerization. The study highlights the feasibility of recycling waste PET into valuable aromatic nitriles through in situ catalytic pyrolysis with urea and enhances the understanding of the pyrolysis process.

New criteria to select reasonable hyperparameters for kinetic parameter estimation in distributed activation energy model (DAEM) by using neural network

The utilization of biomass is being actively explored to reduce net emissions of CO2. Solid carbon such as biomass is a mixture of various components that are difficult to separate, and it is not easy to evaluate its reactivity. The distributed activation energy model (DAEM) is often used to evaluate the reactivity of solid feedstocks such as biomass and coal. In our previous study, we proposed DAEM-NN, a method to estimate the model parameters using a neural network. In this study, we propose a new criterion Φ for selecting the optimal hyperparameters in DAEM-NN: by minimizing Φ, we can select hyperparameters that maximize both the conversion prediction accuracy and the typical importance of each reaction in a parallel reaction system. To verify the usefulness of the proposed criterion, reaction data were generated by numerical simulation, and the number of hidden layer, and the lower limit of contribution were optimized to minimize Φ. The hyperparameters that minimize Φ reduced the set of kinetic parameters corresponding to less important responses from the DAEM-NN kinetic analysis results.

Kinetics of thermal decomposition of crude oils: Insights from principal component analysis and products characterization

Energy demand is souring, and fossil fuel reserves are dwindling, making heavy oil resources more attractive. In this study, thermogravimetric and Py-GC/MS analyses were conducted on Iranian crude oil samples to compare high and low API (American Petroleum Institute) crude oils. A kinetic study based on mass loss of crude oil was performed using three model-free methods and distributed activation energy model (DAEM). To do that, TG analysis carried out, the temperature was increased from room temperature to 1000 °C with heating rates of 10, 20, and 30 °C min−1. Activation energy (Ea) and pre-exponential factor (A0) were estimated from Friedman, Kissinger–Akahira–Sunose (KAS), and Ozawa-Flynn–Wall (OFW) methods for oil sample. The Ea and A0 for heavy crude oil (Koroosh) pyrolysis varied between 59.85 and 193.83 kJ mol−1 and 1.34 × 105 to 4.36 × 1011 s−1, respectively. For light crude oil sample Lavan, the Ea and A0 ranged between 35.93 to 62.89 kJ mol−1 and 337.41–722.65 s−1, respectively. Pearson's correlation analysis found that the activation energy barrier increases as the reaction progresses and the temperature rises. This makes it harder to form the activated complex, which is a key step in the reaction. Principal component analysis supported these findings. Saturated and aromatic hydrocarbons were liberated at mild temperature while the resins and asphaltenes consecutively released in favorable condition for developing sustainable heavy oil recovery systems. Py/GC–MS analysis shows the evolution of saturated hydrocarbon in Koroosh-oil and aromatic hydrocarbons in Lavan-oil and demonstrates their suitability for fuel applications.