Biomass Pyrolysis Research Articles

Energy potential of plant and animal biomass using in relation to its thermal processing

Relevance. The need for effective utilization of biomass waste generated in significant quantities. Pyrolysis, accompanied by exothermic reactions, is a promising way of biomass processing. Aim. Assessment of the possibility of covering the thermal costs of plant and animal biomass pyrolysis due to heat release during decomposition. Methods. Proximate and ultimate analysis of biomass are determined according to certified methods. Thermal analysis of the studied raw materials was carried out on a Netzsch STA 449 F5 Jupiter synchronous thermal analyzer with an integrated gas analyzer QMS 403 Aeolos; quantitative yield of pyrolysis products was determined according to GOST 3168-93, gas composition was established using the gas analyzer TEST-1 (БОНЭР, Russia). Results and conclusions. According to the results of thermal analysis, it was found that pyrolysis of plant (pine nut shells) and animal (cattle manure) biomass is accompanied by exothermic reactions associated with the organic part decomposition in the temperature range 240–700°C. The value of heat release of exothermic reactions during pine nut shell destruction is 1.39 MJ/kg, a similar value during manure decomposition is 0.31 MJ/kg. This amount of heat allows you to fully cover the thermal costs of pine nut shell pyrolytic processing, the share of covering the thermal costs of manure pyrolysis is ∼30%. An additional source of heat is pyrolysis gaseous products with energy potential equal to 3.28 and 1.58 MJ of thermal energy per 1 kg of processed pine nut shells and manure, respectively.

Revealing the delithiation process of spent LiMn2O4 and LiNi0.6Co0.2Mn0.2O2 batteries during the biomass-assisted gasthermal and carbothermal reduction

The utilization of biomass-assisted pyrolysis in the recycling of spent lithium-ion batteries has emerged as a promising and reliable process. This article furnishes theoretical underpinnings and analytical insights into this method, showcasing sawdust pyrolysis reduction as an efficient means to recycle spent LiMn2O4 and LiNi0.6Co0.2Mn0.2O2 batteries. Through advanced thermogravimetry-gas chromatography-mass spectrometry analysis complemented by traditional thermodynamic demonstration, the synergistic effects of biomass pyrolysis reduction are elucidated, with minor autodecomposition and major carbothermal and gasthermal reduction pathways identified. The controlled manipulation of transition metals has demonstrated the capability to modulate surface pyrolysis gas catalytic reactions and facilitate the preparation of composite materials with diverse morphologies. Optimization of process conditions has culminated in recovery efficiency exceeding 99.0 % for LiMn2O4 and 99.5 % for LiNi0.6Co0.2Mn0.2O2. Economic and environmental analyses underscore the advantages of biomass reduction and recycling for these two types of spent LIBs: low energy consumption, environmental compatibility, and high economic viability.

Adsorption of heavy metal ions by carbon-based adsorbent using magnetic nitrogen-doped carbon and graphene oxide

ABSTRACT The adsorption of weighty metal particles from contaminated water sources has garnered significant attention due to its critical role in environmental remediation and ensuring safe drinking water. Heavy metal ions can be removed from water using conventional adsorbents such as activated zeolites; however, these materials have low absorption and slow kinetics. To solve these issues, carbon-based adsorbents that exhibit easy synthesis, high porosity, design ability, and stability have been proposed. In this review, a carbon-based adsorbent, named M-NC, and graphene oxide were created for the particular evacuation of weighty metal particles. To increase the potential for Heavy Metals (HM) immobilization, sulfide-modified biochar was created via a process called synchronous carbon layer epitome. A hypothetical physicochemical and thermodynamic examination of the adsorption of weighty metals Zn2+, Cd2+, Ni2+, Ag2+, Pb2+ and Cu2+ on carbon-based adsorbents was done with factual material science fundaments. The biochar with large surface areas is utilized to eliminate weighty metal particles, quite possibly the most significant heavy metal pollutants, from aqueous solutions. The limit of the adsorbent for eliminating weighty metal ions was concentrated on utilizing Langmuir adsorption isotherm under ultrasound-helped conditions. The Mesoporous Silica Nanoparticles (MNCs) can be applied to the Langmuir model and pseudo-second-order kinetics. It is possible to use the Langmuir and second-order kinetic equations to accurately explain the adsorption method. Thermodynamic limitations were also envisioned because sorption is exothermic when it happens spontaneously. A homogeneous measurable physical science adsorption typically was utilized to describe and analyze the experimental heavy metal removal isotherms at 30°C and pH5 utilizing adsorbents produced by pyrolysis of biomasses (broccoli stalks). The experimental results were investigated in terms of Langmuir and pseudo-2nd-order kinetic equations, Freundlich and isotherm models. The outcome of pH, initial heavy metal ion concentration, contact time, and adsorbent dosage regarding the adsorption capacity and removal efficiency of Pb2+ and Cd2+ on the hydrogel was examined. This study contributes to the advancement of information in the ground of environmentally friendly heavy metal removal techniques, specifically focusing on the usage of biomass-based adsorbents. These findings have the potential to address the need for effective solutions in water purification and environmental cleanup efforts.

Preparation of carbon materials by vapor deposition with Fe3+-Modified nickel foam from biomass pyrolysis gas

Biomass carbon materials have attracted attention in various fields due to their excellent properties. In this study, CH4 derived from biomass pyrolysis was utilized as a carbon source gas to synthesize carbon materials by chemical vapor deposition (CVD) in a two-stage reactor with purification system, with Fe3+-loaded nickel foam as the substrate under an argon atmosphere, using a self-designed experimental platform. The reaction process was optimized by examining the effects of the catalyst type, reaction temperature, reaction time, and gas flow rate on the structure and morphology of the carbon materials. The optimal preparation condition was to use FeCl3 ethanol solution as catalyst, with CH4 flow rate of 50 ml/min at 1000 °C for 25 min. The high quality carbon materials with uniform diameters (250–500 nm) were obtained on nickel foam substrate. The carbon materials obtained under optimal conditions were characterized and analyzed to investigate their excellent properties. Surface morphology and structure of as-formed carbon materials were characterized by SEM. The analysis of the XRD spectra and the Raman spectroscopy showed that the graphite diffraction peak (002) at 26.6°, the calculated intensity ratios for ID/IG and I2D/IG were 0.257 and 0.545, respectively, indicated high degree of graphitization and purity of the carbon materials. Furthermore, the growth mechanism of carbon materials on the nickel foam substrate was discussed.

Closing the loop: Biochar-supported nickel catalyst for efficient hydrogen-rich syngas production

Thermochemical conversion of agricultural by-products into hydrogen-rich syngas is a technology that offers both economic and environmental benefits. In this work, we investigated a biochar-supported nickel-based catalyst for the catalytic pyrolysis of straw biomass to produce hydrogen-rich syngas. The by-product, straw biochar, was used as a material for synthesizing fresh catalysts, achieving a closed-loop process. We explored gas yields under various conditions. The highest yields of CO and H2, reaching 0.52 L/g and 0.48 L/g, respectively, were obtained under the conditions of a pyrolysis temperature of 900 °C, a residence time of 20 min, a calcination temperature of 400 °C, a nickel loading of 15 wt%, and a citric acid to potassium hydroxide ratio of 1:4. The catalysts were characterized using XRD, H2-TPR, SEM, and TEM. The results demonstrated that biochar provides excellent support and synergy, enabling the catalyst to function at high temperatures and offering antioxidative protection to the active metals during the thermal process. Overall, this catalytic pyrolysis process, aiming for green and efficient conversion, achieved high yields of syngas and hydrogen.

Exploring and understanding the microwave-assisted pyrolysis of waste lignocellulose biomass using gradient boosting regression machine learning model

The production of bio-oil is a complex process influenced by various parameters. Optimizing these parameters can significantly enhance bio-oil yield, thus improving process efficiency. This study aims to develop a predictive model for bio-oil yield using the Gradient Boosting Regression (GBR) technique. It also seeks to identify the key factors affecting bio-oil yield and determine the optimal conditions for maximizing production. The GBR model was constructed using data collected from the literature. The model's performance was evaluated based on its determination coefficients for training and testing datasets. Optimization studies were conducted to identify the best conditions for bio-oil production. The GBR model demonstrated high precision, with determination coefficients of 0.983 and 0.913 for the training and testing datasets, respectively, indicating its effectiveness in predicting bio-oil yield. The optimal conditions for maximizing bio-oil yield were identified as 20 min of pyrolysis time, a temperature of 771 °C, and 524W of microwave power. The two-way PDP analysis provided valuable insights into the interactive effects of temperature with other factors, enhancing the understanding of the dynamics of the bio-oil production process. This study not only identifies the most impactful variables for bio-oil yield but also offers critical guidance for optimizing the production process.

Green Synthesis of Biochar@Al2O3 Nanocomposite from Waste Melia azedarach Fruit Biomass Pyrolysis: A Sustainable Solution for Photocatalytic Methylene Blue Dye Degradation

In this work, a green and sustainable approach used for synthesis of novel biochar@Al2O3 nanocomposite through pyrolysis of Melia azedarach (chinaberry) biomass coupled with Al2O3 nanoparticles from Phyllanthus emblica seed extract. The synthesized nanocomposite was analysed by UV-Vis spectroscope, FTIR, SEM, EDX and XRD were used to authenticate the distinct properties of the biochar@Al2O3 nanocomposite. These techniques are further used to examine the nanocomposite after photocatalytic degradation of methylene blue. Additionally, the scavenger impacts on dye degradation, stability and the potential reusability of the biochar@Al2O3 nanocomposite were examined in detail. The investigation evaluating the photocatalytic capability of biochar@Al2O3 nanocomposite for methylene blue degradation in wastewater revealed an impressive degradation efficiency of 97.36 %. Furthermore, after five cycles of reuse the nanocomposite retained a substantial degradation efficiency of 84.59 %. This research highlights the importance of presenting an efficient and eco-friendly method for water purification, emphasizing the role of biochar@Al2O3 nanocomposites in addressing environmental pollution through innovative nanomaterial applications. Significantly progresses was made in the development of sustainable materials for wastewater treatment, in particular the promising potential of the biochar@Al2O3 nanocomposite in methylene blue dye degradation.

Microwave-assisted pyrolysis of industrial biomass waste: Insights into kinetic, characteristics and intrinsic mechanisms

Microwave-assisted pyrolysis is the preferred technology for enhancing the production of fuels and valuable chemicals. Therefore, pyrolysis experiments of furfural residue (FR) were performed using microwave equipment without microwave-absorbing additives. Further, to explore the interactions and intrinsic mechanisms of biomass components, thermogravimetric (TG), kinetic calculation, Py-GC/MS and TG-MS were also employed. Results showed that the temperatures and catalysts both affect the yields and compositions of products. Moreover, kinetic calculations showed a high-level consistency between FR pyrolysis and P3 mechanism. The product analysis also helps in the resolution of pyrolysis mechanism. For example, crystal substances in biochar were mainly SiO2, K2SO4, KAlSi3O8, and K2SO4 enhanced the reaction degree of biomass. While for bio-oil, the yield reached maximum (∼25 wt%) at ∼550 °C. The pH of bio-oil was acidic (2–4.3), and the main product in bio-oil was phenols, which was found the highest (84.63 %) at 700 °C. Interestingly, the interaction of cellulose and lignin promoted light hydrocarbon production. This research unveils innovative perspectives on the intrinsic mechanisms underlying microwave-assisted pyrolysis of biomass, which provides guidance for optimization of the microwave-assisted pyrolysis technology.

Integrating solar-driven biomass gasification and PV-electrolysis for sustainable fuel production: Thermodynamic performance, economic assessment, and CO2 emission analysis

Biomass gasification provides a promising pathway for sustainable fuel production. Nevertheless, its development is hindered by lower efficiencies in biomass–to–fuel energy conversion and carbon utilization, along with restricted scale due to economic collection radius. To tackle these challenges, a solar–biomass hybrid gasification system is proposed for sustainable fuel production. The system employs parabolic trough and tower concentrators to generate solar heat, driving the biomass pyrolysis and pyrolysis products gasification reactions to produce bio–solar syngas. The high–density bio–oil and char produced in distributed pyrolysis units can be economically transported to the centralized gasification plant. Moreover, PV–electrolysis water is utilized to generate H2 and O2, which are used to adjust syngas composition and substitute for air separation O2, respectively. Consequently, the energy consumption for water–gas shift, CO2 separation, and air separation units can be reduced. Thermodynamic, economic, and CO2 emission performance are analyzed for a typical case of methanol production using corn residue. The total energy conversion efficiency of the hybrid system can reach 65.01 %, representing an improvement of 6.57 % compared to the conventional biomass gasification system. The fuel production cost is estimated to be $354.1 per ton, falling within the market price range. Additionally, the greenhouse gas emissions to produce unit kg methanol can be reduced by 0.63 kg CO2eq. Furthermore, we analyzed the performance of six representative fuel production scenarios involving different types of biomass feedstocks. Finally, the limitations of this work and the feasibility of its practical applications are discussed. This study offers an innovative approach to bio-solar fuel production, promoting the development of circular bio-economy and the application of sustainable fuel.

Transcriptome profiling reveals the impact of various levels of biochar application on the growth of flue-cured tobacco plants

BackgroundBiochar, a carbon-rich source and natural growth stimulant, is usually produced by the pyrolysis of agricultural biomass. It is widely used to enhance plant growth, enzyme activity, and crop productivity. However, there are no conclusive studies on how different levels of biochar application influence these systems.Methods and resultsThe present study elucidated the dose-dependent effects of biochar application on the physiological performance, enzyme activity, and dry matter accumulation of tobacco plants via field experiments. In addition, transcriptome analysis was performed on 60-day-old (early growth stage) and 100-day-old (late growth stage) tobacco leaves to determine the changes in transcript levels at the molecular level under various biochar application levels (0, 600, and 1800 kg/ha). The results demonstrated that optimum biochar application enhances plant growth, regulates enzymatic activity, and promotes biomass accumulation in tobacco plants, while higher biochar doses had adverse effects. Furthermore, transcriptome analysis revealed a total of 6561 differentially expressed genes (DEGs) that were up- or down-regulated in the groupwise comparison under different treatments. KEGG pathways analysis demonstrated that carbon fixation in photosynthetic organisms (ko00710), photosynthesis (ko00195), and starch and sucrose metabolism (ko00500) pathways were significantly up-regulated under the optimal biochar dosage (600 kg/ha) and down-regulated under the higher biochar dosage (1800 kg/ha).ConclusionCollectively, these results indicate that biochar application at an optimal rate (600 kg/ha) could positively affect photosynthesis and carbon fixation, which in turn increased the synthesis and accumulation of sucrose and starch, thus promoting the growth and dry matter accumulation of tobacco plants. However, a higher biochar dosage (1800 kg/ha) disturbs the crucial source-sink balance of organic compounds and inhibits the growth of tobacco plants.

Biochar Meets Single-Atom: A Catalyst for Efficient Utilization in Environmental Protection Applications and Energy Conversion.

Single-atom catalysts (SACs), combining the advantages of multiphase and homogeneous catalysis, have been increasingly investigated in various catalytic applications. Carbon-based SACs have attracted much attention due to their large specific surface area, high porosity, particular electronic structure, and excellent stability. As a cheap and readily available carbon material, biochar has begun to be used as an alternative to carbon nanotubes, graphene, and other such expensive carbon matrices to prepare SACs. However, a review of biochar-based SACs for environmental pollutant removal and energy conversion and storage is lacking. This review focuses on strategies for synthesizing biochar-based SACs, such as pre-treatment of organisms with metal salts, insertion of metal elements into biochar, or pyrolysis of metal-rich biomass, which are more simplistic ways of synthesizing SACs. Meanwhile, this paper attempts to 1) demonstrate their applications in environmental remediation based on advanced oxidation technology and energy conversion and storage based on electrocatalysis; 2) reveal the catalytic oxidation mechanism in different catalytic systems; 3) discuss the stability of biochar-based SACs; and 4) present the future developments and challenges regarding biochar-based SACs.

Co-pyrolysis Behavior of Coal and Biomass: Synergistic Effect and Kinetic Analysis.

Co-pyrolysis of coal and biomass is an efficient way to utilize resources. This study investigates the co-pyrolysis behavior and kinetics of coal and biomass using thermogravimetric analysis (TGA) and TG-FTIR. Co-pyrolysis of coal and biomass exhibits a synergistic effect. When the biomass is 25%, the weight loss increases, showing a positive synergistic effect. When the biomass is 50%, it exhibits a negative synergistic effect. Increasing the heating rate can promote the generation of a synergistic effect. Co-pyrolysis involves two central pyrolysis stages: stage III (250-380 °C) and stage IV (380-550 °C). Friedman, FWO, KAS, and STA methods are used to calculate the activation energy for stages III and IV. The activation energy (E α) for co-pyrolysis is higher than that for coal or biomass pyrolysis alone. A positive synergistic effect is observed in stage III, while a negative synergistic effect is noted in stage IV. The master curve method determines an accurate reaction order (n) and pre-exponential factor (A) value of Coal75-Bio25. In stage III, E α = 238.81 kJ/mol, n = 2.4, A = 1.30 × 1021 s-1. In stage IV, E α = 37 8.01 kJ/mol, n = 4.0, A = 1.10 × 1027 s-1. The kinetic parameters in stage IV are significantly higher than those in stage III. TG-FTIR is used to analyze the synergistic effect of co-pyrolysis. Compared with coal and biomass pyrolysis separately, the Coal75-Bio25 pyrolysis process releases less CO2 and more CH4. These findings support the synergistic effect of coal and biomass during co-pyrolysis.

Interpretable machine learning model for activation energy prediction based on biomass properties

A thorough understanding of pyrolysis kinetics for biomass is crucial for the process design, feasibility assessment, and scale-up in industrial scenarios. To reduce the time and economic cost invested in obtaining experimental kinetic data by performing the thermogravimetric analysis, a data-driven machine learning method was proposed in the present work. Random forest (RF), gradient boosting decision tree (GBDT), and extreme gradient boosting (XGB) algorithms were utilized to predict the activation energy versus conversion range with ten input features from biomass characteristics. Among these XGB has shown the most competitive prediction accuracy with a coefficient of determination (R2) higher than 0.98 and a root mean squared error (RMSE) = 7.7 kJ/mol. To enhance the model interpretability of the derived model, a visualized analysis for individual impact and interactions of variables was conducted by Shapley additive explanation (SHAP). The top three significant inputs for the model established by the current dataset are conversion rate, volatile content, and moisture content. This work provides a quick and accurate kinetic prediction method for unexploited biomass and favors detailed insights into the complicated associations between biomass characteristics and pyrolysis kinetics.

Sustainable Al2O3 nanoparticles in catalytic pyrolysis: Unlocking high-yield bio-oil from Melia azedarach fruit biomass with comprehensive physicochemical analysis

The catalytic pyrolysis of Melia azedarach fruit biomass in the presence of aluminium oxide (Al2O3) nanoparticles was studied using a fixed bed reactor. Cost-effective and sustainable Al2O3 nanoparticles were employed as a catalyst in biomass pyrolysis and these nanoparticles were synthesized by using the extract of Phyllanthus emblica seeds as a reducing and capping agent. The confirmation of fabricated Al2O3 nanoparticles was analyzed by EDS, SEM and XRD characterization techniques. The potential effects of pyrolysis process parameters including catalyst dose, temperature and time were investigated. The optimized catalytic bio-oil was further characterized by FTIR spectroscopy. Moreover, physiochemical analyses were also performed to examine the bio-oil properties as fuel. This study demonstrates that catalytic bio-oil produced from Melia azedarach fruit biomass has the potential to be used as a substitute for fossil fuel for the generation of energy and industrial applications.

Biochar produced from waste‐based feedstocks: Mechanisms, affecting factors, economy, utilization, challenges, and prospects

AbstractBiochar possesses unique characteristics, including a substantial surface area, a high carbon content, sufficient capacity for cation exchange, and a robust structure. However, biochar contains hazardous pollutants like volatile organic compounds that harm soil properties and functionality. Although several studies on biochar production from various feedstocks have been undertaken in recent years, several issues about feedstock preparation, economic feasibility, influencing factors, and the proper utilization of biochar production processes need to be addressed. This paper thus addresses these issues by providing potential solutions identified through a comprehensive review. Slow pyrolysis of lignocellulosic biomass and Acacia nilotica yields biochar from 20 to 52 wt% at various temperatures and residence times. Biochar yield varies from 29 to 48.3 wt% when waste tires and corn stalks are rapidly pyrolyzed at higher temperatures and for shorter periods. Torrefaction of algal biomass at moderate temperatures with different residence times can result in a substantial yield of 50–60 wt%. However, the variability and heterogeneity of waste feedstocks pose potential challenges affecting biochar's quality and properties. Given its widespread use in carbon sequestration, soil remediation, wastewater purification, and organic waste composting, the mechanisms of biochar production in environmental usage need to be investigated.

Optimization of Torrefaction Parameters Using Metaheuristic Approach

The probabilistic technique was used to optimize the torrefaction parameters that indirectly influence the yield of end-products obtained through the pyrolysis of biomass. In the same pursuit, pine cones underwent thermal pre-treatment at 210 °C, 220 °C, 230 °C, 240 °C, and 250 °C in the presence of N2 gas with a flowing rate of 0.7 L∙s−1, whereas the duration of the pre-treatment process was 5 min, 10 min, and 15 min at each. To facilitate the processing of pine waste, a muffle furnace was improvised for pilot-scale testing. The thermal process used to carry out torrefaction was quasi-static. The average dynamic head of volatile gases inside the chamber was 1.04 m. The criteria for determining the optimal solution were based on calorific value, solid yield, energy consumption during the pre-treatment process, and ash handling. In absolute terms, time and temperature did not influence the statistical deviation in cellulose and hemicellulose decomposition after thermal pre-treatment. While considering ash content as a primal factor, thermal processing should be conducted for 5 min at 210 °C for the bounded operating conditions, which are similar to the operating conditions obtained experimentally. The optimal solid yield would be obtained if the thermal pre-treatment is performed at 250 °C for 5 min. The solution derived through a simulated annealing technique provided a better convergence with the experimental dataset.

Biomass Valorization through Catalytic Pyrolysis Using Metal-Impregnated Natural Zeolites: From Waste to Resources.

Catalytic biomass pyrolysis is one of the most promising routes for obtaining bio-sustainable products that replace petroleum derivatives. This study evaluates the production of aromatic compounds (benzene, toluene, and xylene (BTX)) from the catalytic pyrolysis of lignocellulosic biomass (Pinus radiata (PR) and Eucalyptus globulus (EG)). Chilean natural zeolite (NZ) was used as a catalyst for pyrolysis reactions, which was modified by double ion exchange (H2NZ) and transition metals impregnation (Cu5H2NZ and Ni5H2NZ). The catalysts were characterized by nitrogen adsorption, X-ray diffraction (XRD), ammonium programmed desorption (TPD-NH3), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). Analytical pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS) allowed us to study the influence of natural and modified zeolite catalysts on BTX production. XRD analysis confirmed the presence of metal oxides (CuO and NiO) in the zeolite framework, and SEM-EDS confirmed successful metal impregnation (6.20% for Cu5H2NZ and 6.97% for Ni5H2NZ). Py-GC/MS revealed a reduction in oxygenated compounds such as esters, ketones, and phenols, along with an increase in aromatic compounds in PR from 2.92% w/w (without catalyst) to 20.89% w/w with Ni5H2NZ at a biomass/catalyst ratio of 1/5, and in EG from 2.69% w/w (without catalyst) to 30.53% w/w with Ni5H2NZ at a biomass/catalyst ratio of 1/2.5. These increases can be attributed to acidic sites within the catalyst pores or on their surface, facilitating deoxygenation reactions such as dehydration, decarboxylation, decarbonylation, aldol condensation, and aromatization. Overall, this study demonstrated that the catalytic biomass pyrolysis process using Chilean natural zeolite modified with double ion exchange and impregnated with transition metals (Cu and Ni) could be highly advantageous for achieving significant conversion of oxygenated compounds into hydrocarbons and, consequently, improving the quality of the condensed pyrolysis vapors.

Mechanism, thermochemistry, and kinetics of formation of PhC(O)H and HOPhC(O)H during unimolecular decomposition of P-PhC(O2•)HPhOH.

Bisphenols are one of the main components of bio-oil, produced during the pyrolysis of lignin-containing biomass. Synthetic bisphenols are used in polycarbonate plastics, epoxy resins, and thermal papers. Their mechanism of oxidation is important for the determination of the fire safety of these materials and the possibility of using them as additives in fuels for the decrease and description of ignition delays, as well as for the determination of their health risk assessment in medicine. One representative of bisphenols is p-benzylphenol (p-PhCH2PhOH), which is formed during the fast pyrolysis of lignine-containing biomass. Its thermochemistry of oxidation has been partially studied previously. It is shown that the reaction of chain oxidation of p-PhCH2PhOH is thermochemically favorable at low temperatures. However, these studies consider only two pathways of this reaction: (1) the chain oxidation of RH by RO2• and (2) the tautomerization of R'HO2• to R'O2H with following production of R'O• and OH radicals. At the same time, the reactions of intramolecular rearrangement of RO2•, produced PhC(O)H and •PhOH or HOPhC(O)H and •Ph, are not reported but can be an important part of its oxidation mechanism. The five DFT (M06-2X (i = 1), B3LYP (i = 2), wB97XD (i = 3), M08HX (i = 4), MN15 (i = 5)) approaches with 6-311 + + G(d,p) basis set are used for the determination of standard enthalpies of atomization (ΔraH°(Xi)) of considered compounds (molecules, radicals, and transition states). These values of ΔraH°(Xi) are corrected using the empirical linear calibration dependencies, reported previously. The different calibration dependencies are used for the hydrocarbons (including the aromatics and simple oxygenated derivatives) and for the peroxides. The corrected values of ΔraH°(Xi, CORR) are used according to Hess's law for the determination of ΔfH°(Xi, CORR). The most consistent values of ΔfH°(X, MEAN) are derived from the coordination of the values of ΔfH°(Xi,CORR) using the intersection of their values of standard deviations (3SDi). These values of ΔfH°(X, MEAN), as well as the B3LYP values of S°(X), which are accounting the frequencies correction and internal rotations, as well as their temperature dependencies, are used for the determination of thermochemistry of considered reactions and of the calculation, within transition state theory (TST), of the values of high pressure limits of the rate constant. The values of H°(Xi), S°(Xi), and G°(Xi) are calculated using the Gaussian 16w program. The considered mechanism is prepared using ISIS/Draw package. The temperature dependencies of thermochemical properties and the values of rate constants are determined using the ChemRate program (v.1.5). The optimized structures are visualized using the Chemcraft package.

Characteristics and kinetics of in-situ catalytic cracking of biomass tar in a micro dual bed reactor

This research introduces a novel micro dual bed reactor, combining rapid pyrolysis in a top-down with a fluidized bed for biomass tar catalytic cracking assessment. The study initially examines the impact of reactor zones on biomass pyrolysis, followed by an exploration of thermal and catalytic cracking behaviors of in-situ biomass tars using three fluidizing media. It delves into the generation of cracking gas and tar cracking reaction kinetics, based on the evolutionary trends of the gas. The process involves two distinct stages (S1 and S2). In S1, olivine shows the highest tar conversion rates at 650 °C and 750 °C, while char peaks at 850 °C. In S2, char leads in conversion rate and reaction time, with a preference for CO and H2. Tar conversion rates at high temperatures follow the order char > olivine > sand, and reaction times vary as olivine > sand > char. Temperature affects tar cracking rates due to thermal and catalytic effects interplay. This study applies an integral method to solve the kinetics under varying conditions, providing insights into tar behaviors during both thermal and catalytic cracking. These findings support designing and optimizing tar removal units in biomass gasification, potentially reducing tar production and enhancing gas quality.

Glossary of terms used in biochar research (IUPAC Technical Report)

Abstract Biochar is the solid carbonaceous product of biomass pyrolysis. The properties of biochar depend on the biomass feedstock as well as the pyrolysis temperature and time. Therefore, biochars with different properties and functionalities can be produced. Biochar research has been intensive in the past 15 years, focusing mainly on soil applications, wastewater treatment, and contaminant remediation. However, a formal definition of biochar and related terms is missing, which hinders the standardization of scientific results worldwide and the scaling-up of research at the industrial level. Furthermore, an official terminology may promote the development of a harmonized legal framework for biochar production and applications, both at regional and national levels. This glossary of terms consists of 178 scientifically sound definitions of the most commonly used terms in biochar research. The definitions of this glossary are interconnected, allowing the reader to further explore the synergies between terms. The distribution of terms reflects the multidisciplinarity of biochar research: chemistry, material science and engineering, and soil science are the main disciplines represented here. The list of terms is by no means exhaustive and the strategic objective of this effort is to develop a dynamic document in which more terms will be added in the future, and the existing ones will be refined, as biochar research evolves.