In the context of the circular bioeconomy and cleaner production, the incorporation of the by-products of plant biomass production in the bioenergy chain is fundamental. However, lignocellulosic ...wastes have properties that hinder their use for the production of biofuels. This study aims to evaluate how blends of lignocellulosic wastes improve the physical, chemical, and mechanical quality of pellets destined to the industrial sector, and to identify the challenges associated with the use of agroforestry biomass as raw material for pelletizing. Pellets were produced from blends of soybean wastes, sorghum wastes, pine needles, rice powder,
Eucalyptus
sawdust, and charcoal fines. Additionally, pure pellets composed of soybean wastes, sugarcane bagasse, and pine wood were evaluated. The effect of biomass type on the energy density, ash content, net heating value, and ultimate analysis was significant. The pellets produced with soybean wastes presented high contents of N (3.5–4.9%) and ashes (16.4–26.7%), besides low mechanical durability (≤ 96%), hindering its commercialization for industrial purposes. Pellets with sugarcane bagasse presented N (1.5%), S (0.03%), ashes (5.6%), mechanical durability (96.6%), and net heating value (15.1 MJ kg
−1
), suitable for industrial energy use in accordance with ISO 17225-6. The high N and ash contents and the low mechanical durability are the greatest challenges for the energy use of pellets produced from Brazilian agroforestry wastes.
Coarse Woody Debris (CWDs) are constantly exposed to the natural decomposition process of wood, which can lead to a change in its physical-chemical properties. However, these changes have not yet ...been fully elucidated, requiring further studies to help to understand the effect of this process on CWDs degradation. Thus, the objectives of this study were: (i) verify if the decomposition affects the physical-chemical properties of the CWDs; (ii) verify if the structural chemical composition of the CWDs is altered as a function of decomposition, using immediate chemical and thermogravimetric analysis. Wood samples were collected from the CWDs to carry out these analyses, considering pieces with diameters ≥ 5 cm separated into 4 decay classes. The results indicated that the average apparent density decreased as a function of the increase of CWDs decomposition (0.62-0.37 g cm
). The averages contents of Carbon and Nitrogen suffered less impact with the increase of CWDs decompositions, ranging from 49.66 to 48.80% and 0.52 to 0.58%, respectively. Immediate chemical and thermogravimetric analysis indicated a loss of holocelluloses and extractives and an increase in the concentration of lignin and ash throughout the decomposition process. The weight loss analyzed by thermogravimetric analysis was greater for less decomposed CWDs and with larger diameters. The use of these analyzes removes the subjectivity of CWDs decay classes, reducing the number of tests to determine CWDs physical-chemical properties and increasing the studies accuracy focused on the carbon cycle of these materials.
Heat treatment improves some wood properties namely: equilibrium moisture, dimensional stability and durability and mechanical properties. In this study, the heat treatment was applied to woods of ...three natural species from Brazil: Aspidosperma populifolium (peroba mica), Dipteryx odorata (cumaru) and Mimosa scabrella (bracatinga). The woods were heated in an oven under vacuum and under nitrogen, at 180, 200, and 220°C for one hour. The untreated and heat-treated woods were characterized in relation to equilibrium moisture content, basic density, shrinkage, Janka hardness, and bending MOR and MOE according to NBR 7190 standards. All the thermal rectified woods showed a reduction in the hygroscopic equilibrium content, especially when the heating was under vacuum from 13-15% in the untreated woods to 1-3% for vacuum treatment at 220°C. The dimensional stability was improved to only a small extent e.g. volumetric shrinkage tended to decrease with increasing temperature. The mechanical properties were affected differently for the three wood species. Heat- treated cumaru showed increased Janka hardness, MOR and MOE; and peroba mica increased MOR and MOE but not Janka hardness; while bracatinga was less influenced by the heat treatment.
Agroforestry industries, such as sugar-alcohol, food, and logging, produce large quantities of waste, used to generate energy from direct burning. The application of other processes, such as ...torrefaction and briquetting, can increase the profits from the use of agro-industrial waste for energy generation. Briquetting is an alternative for using these wastes, allowing the compaction of the biomass, generating a biofuel with high energy density, and which is more homogeneous and easier to store and transport. The objective of this study was to evaluate the physical and chemical properties of four biomass types (wastes from sawed eucalypt and pine wood, coffee pruning wastes, and sugarcane bagasse) torrefied at 300 °C and compacted (briquetting) at pressures of 6.21, 8.27, and 10.34 MPa. The torrefaction increased the fixed carbon content, ash, and calorific value, and reduced the volatile material content and hygroscopic equilibrium moisture of the biomasses. The volatile material content was lower and the fixed carbon higher in the coffee pruning waste, the ash content higher in the sugarcane bagasse, and the calorific value higher in the pine and eucalypt wood. The briquetting and the torrefaction processes increased the biomass bulk density, and the useful calorific value, respectively, and consequently the energy density of the briquettes produced with torrefied raw material under high pressure. The mechanical properties of the briquettes produced with all materials increased with the compaction pressure. Torrefaction and briquetting increased the energy potential of the biomasses evaluated to produce energy from clean technology.
Abstract The charcoal production when performed in woods with high moisture content negatively impacts the pyrolysis and causes an increase of greenhouse emissions. The aim of this study was to ...investigate the effects of moisture on the production and quality of charcoal for the pig iron industry. The slow pyrolysis of Eucalyptus sp. was carried out in four different wood moistures, 0, 20, 40 and 60% (dry base). The charcoal and gas yield decreased according to the increase of wood moisture. On the other hand, the bio-oil yield and charcoal friability increased along with the moisture content. The proximate analysis, bulk density and higher heating value of the charcoal were not influenced by the moisture content. The use of wood with moisture content below 20% in the production of charcoal is an alternative to improve productivity, contributing for the economic sustanainability of this sector.
The differentiation between the charcoal produced from (Eucalyptus) plantations and native forests is essential to control, commercialization, and supervision of its production in Brazil. The main ...contribution of this study is to identify the charcoal origin using macroscopic images and Deep Learning Algorithm. We applied a Convolutional Neural Network (CNN) using VGG-16 architecture, with preprocessing based on contrast enhancement and data augmentation with rotation over the training set images. on the performance of the CNN with fine-tuning using 360 macroscopic charcoal images from the plantation and native forests. The results pointed out that our method provides new perspectives to identify the charcoal origin, achieving results upper 95 % of mean accuracy to classify charcoal from native forests for all compared preprocessing strategies.
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•Near-infrared spectroscopy and chemometrics were used to study the fungal degradation of four different biomass types;•A first developed model classifies raw and torrefied biomasses ...after fungal exposure;•Others models predict energy properties of raw and torrefied biomasses after fungal exposure;•Near-infrared spectroscopy with chemometrics assesses biomass degradation.
Lignocellulosic biomasses have some characteristics that hinder their use as fuel. Further, the biodegradation processes that can occur during storage can affect their energy properties. Torrefaction can improve their energy properties while reducing the impacts of storage. Near-infrared (NIR) spectroscopy could be a promising tool to estimate changes to biomass properties during storage. A series of waste feedstocks, including: sugarcane bagasse, coffee husk, eucalyptus, and pine were torrefied at 290 °C in a screw reactor, over 5, 7.5, 10, 15, or 20 min. Then, raw and torrefied biomasses were submitted to leaching and to white and brown-rot fungi, to simulate storage conditions. The weight loss (WL) due to fungal degradation after 2, 4, 8, and 12 weeks was measured and the high heating value (HHV) of all biodegradation steps, including raw and torrefied samples after leaching, were determined. All the samples were analysed by NIR spectroscopy and chemometric models were then developed. Firstly, partial least squares for discriminant analysis (PLS-DA) models successfully classified the four different residual biomasses into raw and torrefied forms according to fungal decomposition. Secondly, partial least squares regression (PLSR) models showed potential utility in an industrial context as a standardized continuous method to predict the HHV during biomass storage steps. While, PLSR models did not present good accuracy when estimating WL resulting from fungal degradation, they can be useful for screening during decision making. Further studies are required to improve and develop more efficient models to predict the fungal degradation level of stored biomasses. For exemple, in considering the class of torrefied biomasses, the model could show better predictive capacity due to less variability in the data. These results highlight the potential of NIR spectroscopy as a simple, fast, and efficient tool to analyze the degradation process over time. Such a rapid and non-destructive characterization tool could be very useful in industry to assess biomass property changes during storage.
Brazil has a highlighted position in comparison to other countries in relation to the amount of renewable raw materials, as the lignocellulosic wastes, and technologies for production of alternative ...energy. The aim of the study was to evaluate the potential of lignocellulosic wastes such as: from soybean culture, sugarcane bagasse and eucalyptus wood for pellets production focusing the generation of heat energy, and classify them according to the commercialization standards. The properties as heating value, bulk density, energetic density and proximate analysis of the biomasses were evaluated. The pellets were produced with diameter of 6 mm in a horizontal planar array pelletizer. The raw material used generated pellets with eucalyptus and soybean wastes mixed in different proportions, as well was done for sugarcane bagasse and soybean wastes. These mixtures were compared to pellets composed by 100% soybean wastes, 100% sugarcane bagasse and commercial pellets produced with pine wood. The pellets were evaluated through the physical properties (moisture, bulk density and unitary density), energetic properties (heating value and energetic density), chemical properties (volatiles, fixed carbon and ash) and mechanical properties (hardness and mechanical durability). Among the pellets produced, the 100% sugarcane bagasse highlighted by high values for mechanical durability (96.64%), hardness (39.46 kgf) and energetic densities, besides low production of fines (0.18%). Pellets composed by the tested mixtures obtained higher values for heating value, mechanical durability, hardness and lower fines and ashes content in comparison to the pellets composed only by soybean wastes. The increasing of eucalyptus sawdust percentage in the pellets decreased their ashes content in comparison to the 100% soybean wastes (from 26.72 to 14.03%). The sugarcane bagasse pellets showed similar properties to the commercial ones.
Furfural is a versatile, high-value-added platform molecule that can be produced from five carbon atom (C5) carbohydrates present in lignocellulosic biomass. It has numerous industrial applications ...in view and has the potential to replace materials derived from fossil resources. Therefore, in this work, the synthesis of furfural from xylose and corn cob biomass was proposed, using
p
-sulfonic acid calix4arene (CX4SO
3
H) as an organocatalyst, a biphasic system (butyl acetate and saturated aqueous solution of NaCl) and a microwave-assisted (MW) method. Thus, furfural was obtained in 77.0% yield from xylose, by MW at 160 °C for 10 min and using 1.0 mol% of CX4SO
3
H (5 wt%). These same conditions were used for the synthesis of furfural from arabinose, and a yield of 40.5% was obtained. When using corn cob biomass as a substrate, furfural was obtained with 56% yield, by mass, by MW at 160 °C for 60 min and using 12.5 wt% of CX4SO
3
H. In addition to the satisfactory yields, the methodology developed in this work has other advantages, such as obtaining furfural directly from renewable raw materials, saving carbon and generating water as the only by-product, short reaction time, using a recyclable catalytic system (CX4SO
3
H and saturated aqueous NaCl solution), employing a non-corrosive and low-toxicity catalyst and being metal-free. The sum of these characteristics makes the developed process consistent with the principles of green chemistry.
Furfural is a versatile, high-value-added platform molecule that can be produced from five carbon atom (C5) carbohydrates present in lignocellulosic biomass.
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•Biomass stock was determined in different parts of eucalyptus tree.•Wood particles were leached with different water/wood ratio in Soxhlet extractor.•The ion chromatography showed ...greater sensitivity in determining chloride content.•The lowest ratio (25 L.kg−1) removed enough chloride to meet the stranded.•Particle leaching did not significantly affect the energetic properties of wood.
The impacts of climate change caused by the consumption of fossil fuels have encouraged the reduction of greenhouse gas emissions. The use of forest biomass for the pellets production is an alternative for energy generation. However, the high chloride content present in this forest biomass has caused human health and economic problems, which are factors that restrict the export of pellets. The main objective of this work was to reduce the chloride content in eucalyptus wood intended to produce pellets, by leaching the particles with water. Different parts of the eucalyptus tree (bark, branches, leaves, heartwood and sapwood) were characterized, and the biomass stock was determined. The chloride content determination was carried out using the selective chloride electrode and ion chromatography methods. Leaching was performed using a water/wood ratio of 25, 50, 75 or 100 L kg−1. The higher heating value (HHV) of the bark (18.47 MJ/kg), branches (20.01 MJ/kg) and leaves (22.04 MJ/kg) met the requirements of ISO 17225–2. However, their ash (1.91–4.32 %) and chloride content (0.120–0.627 %) were above what is allowed by the standard. The sapwood showed a higher content of volatile matter, ash and holocellulose, while higher values of HHV, fixed carbon, lignin and extractives content were observed for the heartwood. The chloride content present in heartwood was lower than that of sapwood and did not meet the requirements for ISO 17225–2 (≤0.03 % for B and ≤ 0.02 % for A pellets). In general, particle leaching did not significantly affect the energetic properties of wood. Leaching the particles with the lowest water/wood ratio (25 L/kg) was sufficient to remove chloride ions and meet the requirements of ISO 17225–2.
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