Pyrolysis Conditions Research Articles

Study of products derived from the microwave-assisted thermal degradation of high-moor peat

Peat reserves are of great interest for various industries (energy, fuel, chemical, etc.). It is common practice to use pyrolysis to process such solid carbon-containing resources with the subsequent yield of fuel and valuable products. One of the environmentally and energetically favorable ways to degrade carbon-containing feedstock that is currently under development is microwave-assisted pyrolysis. Microwave radiation provides volumetric heating of the material, which significantly increases heating uniformity across the volume of the irradiated sample, providing greater efficiency of heat transfer and avoiding local overheating on the reactor surface. In the conducted study, a system was designed for the microwave processing of organic materials. The structural elements of the system are described, and a schematic showing pyrolysis product separation is presented. A prototype of the developed reactor was used to conduct experiments on degrading high-moor sphagnum peat of the Greko-Ushakovskoe deposit under mild pyrolysis conditions induced by microwave radiation. The component composition of reaction products was analyzed via chromatography-mass spectrometry and compared with the results of previous experiments using conventional thermal pyrolysis. More advanced processing of peat is performed under the conditions of microwave-assisted mild pyrolysis with a high yield of valuable products due to a more efficient heat transfer, uniform heating of the material, and the optimal reaction rate. The developed technology is shown to produce raw materials for a wide range of high-tech industrial productions. The prospects for the industrial use of the proposed microwave-assisted peat processing technology are discussed, specifically for the production of efficient hydrophobic sorbent.

Predicting and refining acid modifications of biochar based on machine learning and bibliometric analysis: Specific surface area, average pore size, and total pore volume

Acid-modified biochar is a modified biochar material with convenient preparation, high specific surface area, and rich pore structure. It has great potential for application in the heavy metal remediation, soil amendments, and carrying catalysts. Specific surface area (SSA), average pore size (APS), and total pore volume (TPV) are the key properties that determine its adsorption capacity, reactivity, and water holding capacity, and an intensive study of these properties is essential to optimize the performance of biochar. But the complex interactions among the preparation conditions obstruct finding the optimal modification strategy. This study collected dataset through bibliometric analysis and used four typical machine learning models to predict the SSA, APS, and TPV of acid-modified biochar. The results showed that the extreme gradient boosting (XGB) was optimal for the test results (SSA R2 = 0.92, APS R2 = 0.87, TPV R2 = 0.96). The model interpretation revealed that the modification conditions were the major factors affecting SSA and TPV, and the pyrolysis conditions were the major factors affecting APS. Based on the XGB model, the modification conditions of biochar were optimized, which revealed the ideal preparation conditions for producing the optimal biochar (SSA = 727.02 m2/g, APS = 5.34 nm, TPV = 0.68 cm3/g). Moreover, the biochar produced under specific conditions verified the generalization ability of the XGB model (R2 = 0.99, RMSE = 12.355). This study provides guidance for optimizing the preparation strategy of acid-modified biochar and promotes its potentiality for industrial application.

Extraction and volatilization mechanism of germanium (Ge) during lignite pyrolysis

Germanium is a critical strategic metal that plays an important role in various industries. Currently, the combustion method is the main method for extracting germanium from germanium-containing lignite, however, its extraction rate of germanium is low, with the form of SiO2-GeO2 solid solution due to covolatilization of both germanium and arsenic. To address these problems, this paper proposes to activate and enrich germanium in lignite through pyrolysis. The results show that the pyrolysis temperature and time are positively correlated with the volatilization rate of germanium, and the optimal pyrolysis conditions are at temperature of 1100°C with the time of 360 min. The volatility of germanium can reach up to 96.85%, and its grade in germanium-rich product is 25.51%, while arsenic content is 0.71%. The germanium-rich product is primarily present as GeS, with no SiO2-GeO2 solid solution, which is conducive to the subsequent chlorinated distillation. The kinetics and thermodynamics of the pyrolysis process are investigated, and the volatilization of germanium during lignite pyrolysis is modeled. These results verify the feasibility of germanium extraction from lignite by pyrolysis, which anticipates to realize the high-grade enrichment of germanium in lignite and the high-value utilization of lignite resources.

Exploring the potential of chemical recycling of waste medium-density fiberboards (MDF) under oxidative and pyrolytic conditions

Medium-density fiberboards (MDFs) have been widely used to replace natural wood in structural and non-structural applications (mostly in furniture). On the positive side, the use of MDF has certainly reduced the level ofdeforestation. However, there is a need to develop a safe and effective treatment method for waste MDF as the presence of chemical additives in MDF and the generation of fine wood dust pose environmental and health challenges. Thermal decomposition of MDF taps into the “waste-to-energy” approach that has been broadly utilized in the disposal of organic-based wastes. Along this line of inquiry, this study entails three aims; (i) to compute thermodynamics and kinetic functions that govern the decomposition of MDF at conditions encountered at real pyrolytic and combustion conditions in waste incinerators; (ii) to acquire the temperature-dependent profiles of decomposition products; and (iii) to report ultimate and proximate analyses of MDF. Under both pyrolytic and combustion conditions, the thermal decay of MDF exhibits three stages that reflect its structural composition. Pertinent thermo-kinetic parameters were computed using model-fitting and iso-conversational formalisms. The nitrogen content in MDF peaked at 6.3%; significantly higher than that of natural wood (i.e., 1%) and originated from the use of urea formaldehyde resin. Chemical analysis indicates that nitrogenated (i.e., N,N-Dimethylacetamide) and oxygenated (i.e., catechol) products dominate the composition of the non-condensable fraction upon pyrolysis and oxidation of MDF. Such a finding calls for the importance of a post-treatment catalytic process that converts N- and O-containing products into pure hydrocarbons. The high nitrogen content in char of MDF indicates its potential utilization as soil nutrients. Values and insights reported herein are to establish a technical foundation for a biorefinery or a thermal facility that uses waste MDF as a feedstock.

Effect of Heat Treatment on the Supramolecular Structure of Copolymers Based on Poly(propylene glycol fumarate phthalate) with Acrylic Acid

Previous studies investigating the thermal decomposition of p-PGFPh:AA copolymers in an inert atmosphere have provided only a general understanding of the changes that occur during thermolysis. Comprehensive studies are required to gain a better understanding of these processes [1]. The most comprehensive information on the influence of various factors on both the kinetics and the supramolecular structure of the resulting products can be obtained by combining the method of thermal analysis with IR, mass spectrometry, and scanning electron microscopy. The compounds studied have two different compositions, namely p‑PGFPh:AA 6.77:93.23 mol % and p-PGFPh:AA 86.67:13.33 mol %. These compounds were then subjected to a thermolysis process, which resulted in the emission of gases and a decrease in sample weight. The degradation process can be divided into three stages: 1) Depolymerization of the main chain; 2) Depolymerization of the side chain; 3) Final decomposition. These processes occur sequentially at different temperature ranges. According to TG- and DTG studies, complete decomposition of p-PGFPh:AA copolymers occurred at Tterm = 340–350 °C. In this temperature range, a slight loss of sample mass (less than 10 wt %) was observed along with a slight gas evolution. The main gaseous products from the transformation of the studied samples were CO and CO2. This was supported by IR-CO (2000–2200 cm−1) and CO2 (2310–2370 cm−1) as well as mass spectrometric observations. The final products resulting from the thermolysis of p-PGFPh:AA copolymers were examined under an electron microscope. The results showed a similar morphological pattern of mesostructures with sizes ranging from 0.3–1.5 μm, which were observed depending on the porous structure of the initial polymer material. Based on the experimental data, it can be concluded that the p-PGFPh:AA copolymers (in proportions of 6.77:93.23 mol % and 86.67:13.33 mol %) have a relatively high degree of resistance to heating and do not undergo any changes in chemical composition, particle size and shape. In conclusion, the results clearly indicate that the selection of conditions for pyrolysis plays a crucial role in increasing the thermal stability of polymeric materials. This method allows for purposeful changes in the structure and properties of polymers.

Co-pyrolysis of cellulose and lignin: Effects of pyrolysis temperature, residence time, and lignin percentage on the properties of biochar using response surface methodology

Cellulose, hemicellulose, and lignin constitute the basic components of biomass. Knowledge of the interactions between cellulose and lignin during pyrolysis is crucial for unraveling the pyrolysis characteristics of biomass. In this study, for the co-pyrolysis of cellulose and lignin to produce biochar, three influencing factors were selected: pyrolysis temperature (400–800 °C), residence time (5–30 min), and lignin percentage (0–100 %). Pyrolysis experiments were conducted in a vertical tube furnace and the impact of these three factors on the characteristics of biochar was comprehensively explored employing response surface methodology. The results revealed obvious differences between actual values and theoretical values. Specifically, the results showed that the interaction between cellulose and lignin increased the biochar yield, oxygen content, volatile content, and ash content by 6.14 %, 22.85 %, 30.95 %, and 46.75 %, respectively. In contrast, the carbon content, fixed carbon content, and HHV of biochar were relatively reduced by 9.38 %, 11.80 %, and 3.3 %, respectively. Furthermore, Raman spectra of biochar showed that the actual value of graphitization degree of biochar was higher than the theoretical value. This was further corroborated by XPS analysis, wherein owing to the interactions between cellulose and lignin, the actual C-C bond content decreased in contrast to the theoretical value. However, the contents of C-O, CO, COOH functional groups, and aromatic rings increased. Finally, the summary of the co-pyrolysis rules of cellulose and lignin provided a reference for optimal pyrolysis conditions and understanding the mechanism of co-pyrolysis.

Structural and magnetic properties of nitrogen-doped carbon materials derived from an ionic liquid precursor

In this report, effects of pyrolysis conditions on the structure and magnetic properties of nitrogen-doped graphitic carbon materials prepared from 1-Buthyl-3-methyl imidazolium tricyano methanide ( [BMIm] [TCM]) ionic liquids(ILs) were investigated. It was found that nitrogen-containing graphitic carbon was formed under pyrolysis temperature of 400 °C or higher. Under the experimental conditions, the maximum nitrogen content of the obtained sample was C4N1.10 at a pyrolysis temperature of 400 °C and it was found that the nitrogen content in the obtained samples decreased with increasing pyrolysis temperature. Ferromagnetism was not observed in all the obtained samples to 2 K. From the value of the orbital diamagnetic susceptibility and XRD, it was found that the obtained sample had the structural characteristics of soft carbon.

Carbon nanotube interweaved Fe7Se8 nanosheet/nanorod hybrids on expanded graphite for high-performance sodium storage

The construction of nano-micro scale hybrid structures by carbon materials is an effective strategy to address the issues of metal chalcogenides when used as anodes of sodium-ion batteries. Herein, we develop a carbon nanotube (CNT)-interweaved Fe7Se8/expanded graphite (EG) composite by means of a facile one-step gas-phase pyrolysis route with ferrocene, selenium and EG as the starting materials. The ex-situ monitoring of the pyrolysis process indicates that the selenium as a promoter facilitates the formation of CNTs and the carbon coated Fe7Se8 nanosheet/nanorod mixture. A competing reaction between CNT growth and the evolution of Fe7Se8 nanostructures occurs, which could be dominated by the concentration of selenium vapor. By optimizing the feeding ratio and the pyrolysis condition, the nanocomponents are homogeneously deposited on the surface of the EG matrix to realize a well-developed nano-micro hybrid configuration. The constructed three-dimensional conductive network, rich mesopores and high specific surface area (107.1 m2 g−1) contribute to substantially enhanced sodium-storage performance in ester electrolyte. Remarkably, the optimized composite electrode exhibits high reversible capacity retention of 97.5 % after 1000 cycles at 1.0 A g−1 and improved rate performance of 325 mAh g−1 at 2.0 A g−1. This study provides new avenues to develop high-performance metal chalcogenide electrodes for electrochemical energy storage.

Adsorption of cobalt isotope from liquid radioactive waste by carbon nanostructured materials of thermochemical activation of sludge-lignin

One of the urgent problems of modern industry is the accumulation of waste. Waste from the nuclear industry is liquid radioactive waste, pulp and paper industry is sludgelignin. To solve the problem of waste accumulation in these industries, a method of selective purification of liquid radioactive waste by waste products of the pulp and paper industry is proposed. Pyrolysis is an effective way of processing sludge-lignin, as a result of the activation of the pyrolysis product by alkaline reagents, activated carbons were obtained in laboratory conditions, which presumably can selectively extract isotopes of radionuclides from liquid radioactive waste. In the conducted study, the ability of carbon nanostructured materials of thermochemical activation of sludge-lignin to extract the isotope Со27 59 in the form of an ammonia complex was studied. The influence of the pyrolysis conditions: temperature (T), time (T) and dosage of the activator (D) on the response functions: monolayer capacity, heat of adsorption, the value of the maximum adsorption and the characteristic adsorption energy, which can be used to judge the porous structure of activated carbon. The method of the planned experiment is applied — rotatable central composite plan. For clarity, response surfaces are constructed based on experimental data. The analysis made it possible to develop practical recommendations for conducting the pyrolysis process in order to obtain a marketable product — activated carbons from sludge–lignin.

Thermal properties and grey correlation degree analysis of tar-rich coal under cryogenic and pyrolysis condition

The thermal properties of coal are important factors that influence the heat and mass transfer during the pyrolysis process. Therefore, thermal properties were investigated for two tar-rich coal under cryogenic temperature and pyrolysis condition using laser flash analyzer. Gray correlation analysis and chemical composition analysis are combined to analyze the impact of chemical properties on thermal properties. With decreasing temperature, the thermal diffusivity of coal experiences a significant increase by 108.9–121.4 %, while the specific heat capacity decreases by 57.9–65.9 %. The volatile matter and fixed carbon content in tar-rich coal have the highest correlation with thermal properties (∼0.9), followed by moisture content (∼0.62), while the ash content has the lowest correlation with thermal properties (∼0.5). The thermal diffusivity of tar-rich coal increases with increasing volatile matter content. Furthermore, within the range of −100 °C to 300 °C, the thermal diffusivity of tar-rich coal decreases with increasing carbon content, while the specific heat capacity increases with increasing carbon content. The results indicate that under low-temperature cryogenic conditions, the internal heat transfer capability of tar-rich coal is significantly improved.

Optimization of Operational Parameters Using Artificial Neural Network and Support Vector Machine for Bio-oil Extracted from Rice Husk.

Bio-oil production from rice husk, an abundant agricultural residue, has gained significant attention as a sustainable and renewable energy source. The current research aims to employ artificial neural network (ANN) and support vector machine (SVM) modeling techniques for the optimization of operating parameters for bio-oil extracted from rice husk ash (RHA) through pyrolysis. ANN and SVM methods are employed to model and optimize the operational conditions, including temperature, heating rate, and feedstock particle size, to enhance the yield and quality of bio-oil. Additionally, ANN modeling is utilized to create a predictive model for bio-oil properties, allowing for the efficient optimization of pyrolysis conditions. This research provides valuable insights into the production and properties of bio-oil from RHA. By harnessing the capabilities of ANN and SVM, this research not only aids in understanding the intricate relationships between process variables and bio-oil properties but also provides a means to systematically enhance the production process. The predictive results obtained from the ANN were found to be good when compared with the SVM. Several models with different numbers of neurons have been trained with different transfer functions. R values for the training, validation, and test phases are around 1.0, i.e., 0.9981, 0.9976, and 0.9978, respectively. The overall R-value was 0.9960 for the proposed network. The findings were considered acceptable, as the overall R-value was close to 1.0. The optimized operational parameters contribute to the efficient conversion of RHA into bio-oil, thereby promoting the use of this sustainable resource for renewable energy production. This approach aligns with the growing emphasis on reducing the environmental impact of traditional fossil fuels and advancing the utilization of alternative and environmentally friendly energy sources.

Pyrolysis of shenmu coal to prepare blue-coke used as reductant

Blue-coke is a form of granular char prepared by medium-low temperature pyrolysis of low-rank coal. As a reductant, it has been widely used in calcium carbide production, ferroalloy, copper pyro refining, and ferrosilicon production in China due to the abundant reserves of raw coal and its excellent performance. However, there is little research on the pyrolysis process of granular coal to produce blue-coke and its characteristics as a reductant. Thus, the effects of pyrolysis temperature, heating rate, particle size and holding time at the final temperature on blue-coke preparation were investigated in a rotary kiln reactor. The quality index of blue-coke as a reductant and its properties, including the element composition, surface function groups, carbon forms, reactivity and lower heating value under different pyrolysis temperatures, were analyzed in detail. It is demonstrated that the pyrolysis temperature had a more significant impact on the quality of blue-coke compared to other pyrolysis conditions. With the rise of pyrolysis temperature, the blue-coke’s C/O and C/H increased. With the particle size and heating rate increased, the temperature gradients developed within the granular coal during the pyrolysis process led to the volatile release shifting to higher temperature zone and more secondary reaction occurrence. Nevertheless, the secondary reaction was restrained in the rotary kiln with good heat and mass transfer. The indexes of blue-cokes as reductants were met by the chars produced at temperatures from 550 oC to 750 oC with a holding time 60 min at this temperature and a heating rate of 10 oC/min. As the key index of blue-coke, the electrical resistivity decreased with the increase of pyrolysis temperature. It was found to be closely related to the removal of H and O heteroatom at the pyrolysis temperature below 700 °C. While at the higher temperature, the development of graphitized carbon structure took a major role on it. Nonetheless, the crystallite sizes of the blue-coke obtained under this low temperature pyrolysis were small and the carbon forms were turbostratic. These resulted in the blue-coke's high combustion reactivity, which would gradually decline with the rise of pyrolysis temperature.

Effects of inorganic sodium on the soot generation of coal particle: Insights with PLIF and DFT calculation

Inorganic sodium in low rank coal exerts significant influence on the soot generation in the early stage of combustion. The effect of inorganic sodium on the PAHs, soot formation and OH generation of coal particle was investigated on a concentrating light heating platform using Planar Laser Induced Fluorescence (PLIF) of OH radicals and PAHs. The generation characteristics of PAHs during coal particles pyrolysis with the temperature of 500 °C and 800 °C were also investigated. Raw coal, acid-washed (AW) coal and AW impregnated with different mass ratio of NaCl (1 %, 3 % and 5 % NaCl-loaded) were studied. Theoretical calculations using density functional theory was performed to explore the effect of sodium on the conversion of small molecule to macromolecular substances during early coal combustion. The results showed that the NaCl addition inhibited the OH radical and soot generation in the early stage of coal combustion, as demonstrated by the reduced OH intensity, and decreased soot intensity by observing the flame luminosity for the NaCl-loaded coals, compared with AW coal. Simultaneously, the PAHs generation was significantly reduced for NaCl-loaded coals, both at the early stage of coal combustion and under pyrolysis conditions, compared with AW coal. The quantum chemistry calculation revealed that the formed C-Na structure enhanced coal structural stability, making the chemical bonds less prone to cleavage, thereby inhibiting the volatile and PAHs release during the early stage of coal combustion. On the other hand, the released Na+ can catalyze the addition reactions of small ring PAHs (naphthalene, naphthalene derivatives) to larger ring PAHs (phenanthrene, pyrene), which would promote the PAHs and soot generation in homogeneous reactions, explaining the highest PAHs with 3-to-5 rings for 5 % NaCl-loaded coal among NaCl-loaded coals. The above two kings of reaction pathways were related to soot formation, but considering the results of reduced soot yield after NaCl addition, the former dominated. Furthermore, the results from the two pathways also illustrated that the Na inhibit the OH formation, which was corresponding to the decreased OH intensity for NaCl-loaded coals, as detected by OH-PLIF, and thus was detrimental to soot consumption. Therefore, the presence of Na in the early stage of combustion inhibited the release of volatiles and PAHs, which was the main reason for the decreased soot generation amount of NaCl-loaded coal.

Size reduction of biochar to nanoscale decrease polycyclic aromatic hydrocarbons (PAHs) and metals content and bioavailability in nanobiochar

Objective of this research was to investigate ball milling of biochar from various feedstocks (willow, rice husk, oilseed rape, sewage sludge) under different pyrolysis conditions (500 and 750 °C, N2 and CO2 atmosphere) on polycyclic aromatic hydrocarbons (PAHs) and metals content. A significant reduction in both total (Ctotal Σ16) (1.1 to 2.4-fold decrease) and freely available (Cfree Σ16) (1.1 to 2.9-fold decrease) PAHs in nanobiochar (n-BC), particularly in sewage sludge (SSL)-derived n-BC was observed. The changes in biochar surface characteristics induced by ball milling, such as surface area, pore volume, and hydrophilicity, contribute to the decreased PAHs content. Mechanisms involving mechanochemical degradation, free-radical reactions, and defects on the biochar surface may explain the decrease of PAHs. The n-BC showed lower log Kd values for PAHs (reduced by 14 to 41 %) compared to bulk biochar (b-BC), indicating reduced effectiveness in immobilizing PAHs. The ball milling significantly reduced also metal contents by 37 to 55 %, especially in willow pellets and agricultural residue (rice husk and oilseed rape straw) with optimal reduction (by 55 %) observed for WL-derived n-BC produced at 650 °C. Importantly, no metals were detected in the aqueous phase after ball milling, ensuring environmental safety of these materials. Reduction mechanisms of metals during ball milling include stable aggregate formation, enhanced defects in crystalline structures, and irreversible adsorption onto new surfaces. The results demonstrate that the application of an eco-friendly ball milling method allows for the production of materials characterized by reduced contamination levels, which is crucial from an environmental protection viewpoint.

Quantifying pore structure heterogeneity of shale samples after solvent extraction following anhydrous and hydrous pyrolysis

Heterogeneity is an important pore structure characteristic of shale formations that can impact reservoir transport properties. To better understand the heterogeneity intrinsic to the shale pore structure, gas adsorption and multifractal theory were combined to analyze data from artificially matured shale samples under both anhydrous and hydrous pyrolysis conditions. We compared two sets of samples: one that was kept intact (not treated with organic solvent), and the other set that was treated with an organic solvent to remove any liquid petroleum that was produced during the pyrolysis process. The results revealed differences in the pore structure parameters of the aliquots under these two pyrolysis conditions as well as treated vs. intact. Furthermore, at the same pyrolysis temperature, the disparity in surface area and pore volume before and after extraction of petroleum was found to be greater with anhydrous compared to hydrous pyrolysis conditions. Regardless of the pyrolysis conditions, when the pyrolysis temperature is under 400 °C, pore structural heterogeneity following extraction of petroleum is often small compared to the situation when yield is still present in the pores. As a result, the movable oil under both maturity routes can increase pore structure heterogeneity. Considering the results, when analyzing shale adsorption data for pore structure heterogeneity, experimental design would have an impact on the final outcome and data interpretation. This is the first study that investigates the effect of the movable oil and solvent extraction process on pore structure heterogeneity in relation to the thermal evolution of shale in the presence and absence of water.

The Microstructure and Mechanical Properties of Si3N4f/BN/SiBCN Microcomposites Fabricated by the PIP Process.

SiBCN ceramics based on SiC, BN and Si3N4 structures have good comprehensive properties such as high-temperature resistance, oxidation resistance, creep resistance and long life, which makes it one of the very promising ceramic material systems in military and aerospace fields, etc. In this study, SiBCN ceramics, as well as Si3N4f/BN/SiBCN microcomposites, were prepared by a polymer infiltration pyrolysis method using PBSZ as the polymer precursor. The PBSZ was completely ceramized by pyrolysis at 900 °C. The weight loss and elemental bonding forms of the products after the pyrolysis of the precursors hardly changed from 600 °C to 900 °C. After pyrolysis at 600 °C for 4 h and using the BN coating obtained from twice deposition as the interfacial phase, a more desirable weak interface of fiber/matrix with a binding strength of 21.96 ± 2.01 MPa can be obtained. Si3N4f/BN/SiBCN ceramic matrix microcomposites prepared under the same pyrolysis conditions have a relatively good tensile strength of 111.10 MPa while retaining a weak interface between the fibers and the matrix. The results of the study provide more theoretical and methodological support for the application of new composite structural ceramic material systems.

Co-Ti Bimetallic Complex-Induced Phase Modulation of Co@Black TiO2 for Catalytic Hydrogenation of Cinnamaldehyde.

Transition-metal-doped black titania, primarily in the anatase phase, shows promise for redox reactions, water splitting, hydrogen generation, and organic pollutant removal, but exploring other titania phases for broader catalytic applications is underexplored. This study introduces a synthetic approach using a Co-Ti bimetallic complex bridged by a 1,10-phenanthroline-5,6-dione ligand as a precursor for the synthesis of cobalt-doped black titania [Co@L2N@b-TiO2]. The synthesis involves precise control of pyrolysis conditions, yielding a distinct structure dominated by the rutile phase over anatase, with active cobalt encapsulated within a nitrogen-doped graphitic layer, primarily as Co0 rather than CoII and CoIII. The synthesized material is employed for the selective hydrogenation of cinnamaldehyde (CAL) to cinnamyl alcohol (COL) under industrially viable conditions. The efficiency and selectivity of Co@L2N@b-TiO2 was compared with other catalysts, including cobalt-doped rutile TiO2 (Co@r-TiO2), anatase TiO2 (Co@a-TiO2), and black titania (Co@b-TiO2) as well as materials pyrolyzed under different atmospheres and temperatures, materials with phenanthroline ligands, and materials lacking any ligands. The superior performance of Co@L2N@b-TiO2 is attributed to its high surface area, stable Co0 within the nitrogen-doped graphitic layer, and composition of rutile and anatase phases of TiO2 and Ti2O3 (referred to as RAT), along with the synergistic interaction between RAT and Co0. These factors significantly influence the efficiency and selectivity of COL over hydrocinnamaldehyde (HCAL) and hydrocinnamyl alcohol (HCOL), indicating potential for broader applications beyond catalysis, particularly in designing of black titania-based materials.

Study on the effect of oil shale ash on potassium retention characteristics during pyrolysis of corn stalk

In a multi-station fast pyrolysis reactor, the influence of oil shale ash on the potassium retention characteristics of corn stalk under different pyrolysis conditions was investigated in the study. The influence of oil shale ash on the potassium migration process during the pyrolysis of corn stalk was elucidated by analyzing changes in the composition and concentration of potassium and other minerals in the pyrolysis semi-coke of corn stalk. This analysis was conducted using inductively coupled plasma emission spectroscopy (ICP-AES), X-ray diffraction (XRD), and complemented by thermodynamic simulation. The findings demonstrate that oil shale ash could fix potassium in corn stalk, and the potassium retention rate peaked when the oil shale ash additive amount reached to 10 %. This is because the silica-aluminum compounds in the oil shale ash reacts with potassium salts in a semi-molten state to produce KAl2Si3AlO10(OH)2, KAlSi3O8, and KAlSi2O6.When the amount of oil shale ash added is increased to 15 %, KAlSi3O8 and KAlSi2O6 in the semi-coke would continue to react with Al2O3 and SiO2, converting to KAl2Si3AlO10(OH)2. Thermodynamic simulation results indicate that the alkali metal potassium in corn stalk semi-coke mainly existed in potassium metasilicate, potassium feldspar, and leucogranite. In order to enhance potassium fixation in corn stalk, the addition of oil shale ash would promote the transformation of potassium-solidifying minerals from potassium metasilicate to potassium feldspar and leucite in the semi-coke.

Atlas of Microscopic Images of Biochar

Derived through the thermochemical conversion of biomass, biochar is a carbon-rich substance recognized for its significance in environmental applications and sustainable agriculture. As interest in its utilization continues to rise, it becomes crucial to comprehend how the source material and pyrolysis parameters influence the properties of biochar and, consequently, to research the suitability of various analytical methods for characterizing it. Despite the current utilization of numerous physical and chemical methods, the untapped potential of reflected light microscopy warrants further exploration. While a few recent studies suggest a correlation between certain microscopic characteristics and selected physical and chemical properties of biochar, the data are limited and difficult to compare. This is primarily due to variations in the types of original biomass used and lack of information about pyrolysis conditions. Moreover, because only a limited number of photographs taken under a reflected light microscope are publicly available to-date, it is difficult to evaluate morphological differences between various biochars and other organic materials such as inertinites from coal, charcoal, etc. To address limited availability of publicly available data, this “Atlas of Microscopic Images of Biochar” presents a collection of more than 300 images contributed by researchers from Poland, the United States, Canada, Australia, Brazil, and Denmark. These photomicrographs capture optical characteristics of a diverse array of biochar, demonstrating its unique morphological and structural features. This visual documentation can serve as a valuable resource for researchers, industry professionals, educators, and enthusiasts interested in investigating the complexities of biochar forms.

Pyrolysis mechanism of a highly branched bio-derived fuel and its blends with aviation kerosene (RP-3)

To address the environmental issues caused by traditional aviation fuels, the use of new alternative jet fuels (AJF) is emerging. C1 fuel, due to its excellent performance, is used as a blended fuel with traditional aviation kerosene. In this study, the pyrolysis pathways of C1 fuel are examined from molecular simulations. Furthermore, C1 fuel is blended with traditional aviation kerosene fuel RP-3 in a 1:4 vol ratio, and the potential coupling effects between two fuels are addressed under both pyrolysis and combustion conditions. In the process of fuel pyrolysis, it is observed that the composition of the fuel has a significant impact on the pyrolysis products. The decomposition process of C1 fuel is mainly dominated by branched-chain alkanes, while the pyrolysis of RP-3 primarily involves β-scission reactions of straight-chain alkanes. By comparing the combustion and pyrolysis processes of fuels, it is found that the combustion of fuel first involves the decomposition of fuel molecules, followed by the oxidation of pyrolysis products. Moreover, it is found that the reaction kinetics of blended fuel can be approximated using the additivity of two neat fuels, indicating a minor chemical coupling. Based on the proportion of C1 and RP-3 in the blended fuel, the mass fractions of key hydrocarbon products, including CH4, C2H2, C2H4, C2H6, C3H6, C4H6, C6H6, and C7H8, can be computed from the simulations of neat fuels. From a molecular perspective, the additivity of the HyChem model in describing the combustion behavior of blended fuels is verified.