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Greenhouse gas (GHG) emissions from Thailand's biomass pellet production were comprehensively assessed, with a specific focus on wood and corn pellets. Employing the extended input and output tables, the anticipated economic and environmental effects of the rising demand for biomass pellets within the Asia–Pacific Economic Cooperation region, which is projected to see an increase exceeding 33% by the year 2050, were investigated. The estimations of CO2, CH4, and N2O emissions, which were conducted utilizing an open Leontief model based on the 2015 National Input–Output Tables, covered each stage of the production process. The results show that emissions from the production of corn pellets are expected to rise steadily, from 52.91 MtCO2e in 2022 to 75.77 MtCO2e by 2030, whereas emissions from wood pellet production are set to increase more substantially, from 210.30 to 301.18 MtCO2e within the same timeframe. Data derived from surveys and interviews with corn farmers and wood pellet manufacturers informed the lifecycle data for the biomass pellet supply chain from cradle to gate. The findings suggest that Thailand's power sector could benefit significantly from the biomass potential in the northern part of Thailand, which boasts an estimated energy content of corncob at 39 ktoe (0.0016 TJ). Market demand scenarios were explored in two forms: one where it was assumed that all biomass pellets are to be exported to Japan and South Korea, expecting a combined demand of approximately 560,262 tons by 2030, and another positing that 10% of production will be reserved for the domestic market, with a forecasted annual increase of 10% from 2020 to 2050. This paper highlights the need to prioritize low-emission renewable energy sources, expand technologies with lower lifecycle emissions, optimize the biomass supply chain to enhance efficiency, and introduce sustainable energy practices. The detailed GHG emissions analysis provides critical insights for policy formulation, underscoring the importance of sustainable transitions in the context of increasing biomass demand. [ABSTRACT FROM AUTHOR]

As global energy demand has increased, bioenergy has emerged as a viable option for reducing greenhouse gas emissions. This study focuses on using waste materials from the sugar industry, such as sugarcane straw, bagasse, and filter cake, to compress into pellets to investigate pelletizing behavior and energy usage. Raw material preparation was a critical phase influencing pelletizing efficiency. Biomass pellet quality depended on a uniform particle size distribution and adequate moisture content. A moisture content of 20% (wb) was found to be suitable for biomass pelletization from the sugar sector. Specific energy in the pelletizing process ranged from 144.28 to 197.85 Wh/kg. The suggested mixing ingredients (sugarcane leaves: bagasse: filter cake) of 0% sugarcane leaves, 90% bagasse, 10% filter cake, and 5% sugarcane leaves, 93.5% bagasse, and 1.5% filter cake resulted in pellets with a bulk density of over 600 kg/m3 and a durability of at least 97.5%. All aspects were assessed according to standardized criteria for developing biomass pellet processing technology from sugar industry byproducts. This method could improve efficiency, boost production volume, lower production costs, and promote the efficient and cost-effective use of renewable energy. [ABSTRACT FROM AUTHOR]

This study evaluates the quality of 30 biomass pellets sold for residential use in Poland. It provides data on their physical, chemical, and petrographic properties and compares them to existing standards and the information provided by the fuel producers. The results reveal considerable variations in the quality of the pellets and show that some of the purchased samples are not within the DINplus and/or ENplus certification thresholds. Among all 30 purchased samples, only one passes the quality thresholds set by the PL-US BIO, a newly established quality certification in Poland that combines quality assessment following DINplus with optical microscopy analysis. The primary issues causing a decrease in pellet quality include elevated ash and fines content, compromised mechanical durability, too low ash melting temperature, and additions of undesired additions like bark, inorganic matter, and petroleum products. Our research highlights the need for improved fuel quality control measures, and transparent and accurate product labeling, as well as the need for a comprehensive and publicly available national database of solid biomass fuel producers and fuels sold. These are essential steps toward increasing customers' awareness and trust, encouraging them to embrace biomass fuels as reliable and sustainable sources of energy. [ABSTRACT FROM AUTHOR]

Greenhouse gas (GHG) emissions from Thailand’s biomass pellet production were comprehensively assessed, with a specific focus on wood and corn pellets. Employing the extended input and output tables, the anticipated economic and environmental effects of the rising demand for biomass pellets within the Asia–Pacific Economic Cooperation region, which is projected to see an increase exceeding 33% by the year 2050, were investigated. The estimations of CO2, CH4, and N2O emissions, which were conducted utilizing an open Leontief model based on the 2015 National Input–Output Tables, covered each stage of the production process. The results show that emissions from the production of corn pellets are expected to rise steadily, from 52.91 MtCO2e in 2022 to 75.77 MtCO2e by 2030, whereas emissions from wood pellet production are set to increase more substantially, from 210.30 to 301.18 MtCO2e within the same timeframe. Data derived from surveys and interviews with corn farmers and wood pellet manufacturers informed the lifecycle data for the biomass pellet supply chain from cradle to gate. The findings suggest that Thailand’s power sector could benefit significantly from the biomass potential in the northern part of Thailand, which boasts an estimated energy content of corncob at 39 ktoe (0.0016 TJ). Market demand scenarios were explored in two forms: one where it was assumed that all biomass pellets are to be exported to Japan and South Korea, expecting a combined demand of approximately 560,262 tons by 2030, and another positing that 10% of production will be reserved for the domestic market, with a forecasted annual increase of 10% from 2020 to 2050. This paper highlights the need to prioritize low-emission renewable energy sources, expand technologies with lower lifecycle emissions, optimize the biomass supply chain to enhance efficiency, and introduce sustainable energy practices. The detailed GHG emissions analysis provides critical insights for policy formulation, underscoring the importance of sustainable transitions in the context of increasing biomass demand.

Tea plantation biomass wastes, such as tea plantation pruning, shade trees, and woody weeds have not been utilized. The waste can be used as renewable energy in the form of wood pellets. The problem is the feasibility of biomass waste to be used as material for making wood pellets as energy. This paper aims to analyze the potential of tea plantation biomass waste as wood pellet material to meet energy needs. The research was conducted in a tea plantation owned by the Tea and Kina Research Center (PPTK). Quantification of biomass waste potential per unit area was conducted in the plantation using direct measurement method. Proximate analysis of each wood pellet variant of biomass waste was conducted to match the quality of Indonesian Wood Pellet Standard. The biomass waste potential in PPTK is 14,281 tons per year which can produce 8,186 tons of wood pellets per year. This potential can meet the needs of wood pellet consumption from the tea production process at PPTK which is around 1.8 tons / day for the tea processing process of 13 tons/day. Based on proximate analysis, the wood pellets produced have a calorific value of 4425 cal/gram, density of 1.35 grams/cm3, fixed carbon content of 85.2%, and volatile matter of 3.72%. These results confirm that the wood pellets comply with the National Wood Pellet Standard (SNI 8021:2014). This can be a model for the application of the Green Circular Economy concept in the plantation sector.

Ghana's Renewable Energy Master Plan of 2019 includes the production and use of biomass pellets. However, pellets have neither been developed commercially nor included in Ghana's energy mix. This paper reviewed the prospect of production, adoption and sustained use of pellets in Ghana. Besides having abundant biomass resources, Ghana has high market demand and relevant policies for pellet development. The production of pellets can significantly replace traditional household biomass demand and improve environmental and health quality. However, the production and use of pellets are limited due to technical, financial, social and policy issues. Our estimates show that 3% of the annual national average household income will be spent on pellet demand for cooking, with the highest burden on rural households in Ghana. Practical measures are required since the cost of pellets and gasifier stoves may limit pellet adoption and use in Ghana. Based on study findings, it is recommended that the government of Ghana establishes a robust supply chain and provides infrastructure for pellet production and use. Existing renewable energy policies should be reviewed to remove ambiguities, attract investment, and build capacity in the renewable energy sector. Apart from raising public awareness of the benefits of pellets use, the government of Ghana should ensure that continuous and thorough impact assessments are undertaken to assess the implications of pellet production and use. This review will inform policymaking on achieving sustainable production, adoption and use of pellets and assess Ghana's contribution to achieving the United Nations' sustainable development goals.

Pellet manufacturing allows for the improvement of the handling properties of biomass streams. Increasing channel length of the ring-die holes generally increases physical pellet quality. This phenomenon is often attributed to an increase in pressure gradient over the die and greater densification of the mash during compaction. It remains unknown, however, to what extent this improvement in physical pellet quality is attributable to the concomitant increase in die volumetric content, and, therefore, longer mean residence time (MRT) of the mash in the die. Here, we aimed to separate the effect of die geometry and MRT on physical pellet quality, by combining a pilot scale pellet manufacturing experiment with capillary rheometric analysis, for mashes containing different fibre-rich coproducts from food production. Net energy costs of compaction (in kWh t−1) were unaffected by production rate. Capillary rheometric analysis indicated that the work of friction between mash and the die hole wall did not increase at flow rates exceeding 1.0 mm3 s−1, suggesting the occurrence of plug flow behaviour. Hence, the work of friction generated between mash and the die hole wall depends on the friction coefficient between mash and the die hole wall and the total surface area of the ring-die. Increasing production rate decreased physical pellet quality (−2.56 to −0.93 kPa (kg s−1)−1). Since the friction generated between mash and the die was unaffected by production rate, we conclude that this reduction in physical pellet quality is attributable to the concomitant reduction in MRT. • Net energy costs of compaction are unaffected by production rate. • Friction between mash and the die hole wall depends on composition, not flow rate. • Mashes display plug flow behaviour at pellet manufacturing conditions. • Physical pellet quality is unaffected by mash viscoelastic deformation in the die. • Increasing mean residence time of mash in the die improves physical pellet quality. [ABSTRACT FROM AUTHOR]

The lack of access to electricity and clean water still affects a substantial proportion of rural areas worldwide, in particular the global south. This paper presents a sustainable polygeneration system that can provide electricity, heat, and drinking water by using agricultural residues in remote rural areas. This polygeneration system consists of a solid biomass-fueled Brayton-Stirling combined cycle system, a boiler, and an air-gap membrane distillation unit. Four different system operation modes were designed to examine the most ideal configurations for maximizing power output, overall efficiency, and/or clean water production, considering a polygeneration system designed for a rural village with daily demands of 13450 kWh electricity and 7.5 m3 drinking water. A thermodynamic analysis are employed to analyze and compare these modes, each operating under steady state conditions. The highest electricity output, up to 160 kW, while the highest clean water is up to 0.7 m3/h. The fuel consumption can reach 0.9 kWh/kg of solid fuel and provide up to 0.0045 m3 of freshwater. In addition, nonlinear multi-objective optimization is used to meet the power demands of typical day in rural areas by varying the polygeneration operation modes and turbine inlet temperature. [Display omitted] • A solid bio-fuel based polygeneration system is developed for a rural village. • It consists of a Brayton-Stirling cycle, a boiler and a membrane distillation unit. • A thermodynamic study is conducted for comparing four designed operation modes. • Flexible operation can be achieved by combining the four operation modes. • The system can provide 1359 kWh electricity and 7.5 m3 clean water per day. [ABSTRACT FROM AUTHOR]

Energy storage is essential to conserve and deliver energy to end-user with continuity and durability. A sustainable energy supply with minimal process losses requires cost-effective and environmentally friendly energy storage material. In this study, self-co-dopes N (3.65 %) and O (6.44 %) porous biochar were produced from pyrolysis of biomass pellets (made from garden wastes) and examined for energy storage application. The presence of co-doped-heteroatoms within the carbon matrix of biochar resulted in enhanced surface wettability, fast charge transfers, increased electrical conductivity, and low internal resistance. Biochar produced at 800 ℃ (i.e. biochar-800) showed desirable pseudocapacitive nature induced by self-co-doped heteroatoms. Two-electrode measurements in aqueous 1 M H2SO4 revealed that biochar-800 possessed 228F g−1 of specific capacitance at a current density of 1 Ag−1. Additionally, biochar-800 exhibited a high energy density of 7.91 Wh kg−1 in aqueous electrolyte and promising cycling stability with 88% capacitance retention after 5000 cycles at 10 A g−1. Enhanced capacitive performance of biochar-800 was assigned to the presence of self-co-doped heteroatom, the high specific surface area of 312 m2g−1, and self-formed mesopores (pore size around 15.2 nm). This study demonstrates the great promise of porous biochar derived from biomass pellets as a low-cost electrode material for high-performance energy storage devices.

Torrefaction in partially oxidative atmospheres is a non-traditional approach to the thermal pre-treatment of biomass. Despite the potential benefits arising from this compared to traditional torrefaction undertaken under costly inert atmospheres, the literature lacks data on the combustion and kinetic analyses of densified biomass torrefied under partially oxidative conditions comparable to those of (reusing) combustion flue gases. This paper, therefore, investigates the effects of partially oxidative atmosphere on the chemical functionality, combustion kinetics and thermodynamics of densified (Australian) woody biomass. Torrefaction was conducted at 250, 275, 300 °C for 30min under both inert and partially oxidative atmosphere (O 2 : 5 vol%, N 2 balance). The kinetic parameters were derived from iso-conversional method over the entire conversion range. Results show that solid biofuel torrefied under partially oxidative atmospheres has superior chemical functionality (e.g., less oxygenates and higher thermal stability), but comparable physical properties to inert atmospheres. In addition, improved thermodynamic features and lower combustion activation energy for partially oxidative torrefied biomass was observed. Overall, the results suggest that the use of partially oxidative atmospheres for torrefaction not only produce a high quality solid biofuel but can also improve process efficiency by using waste heat and flue gases from other combustion processes to thermally pre-treat biomass. [ABSTRACT FROM AUTHOR]

Residential solid fuel combustion significantly impacts air quality and human health. Pelletized biomass fuels are promoted as a cleaner alternative, particularly for those who cannot afford the high costs of gas/electricity, but their emission characteristics and potential effects remain poorly understood. The present laboratory-based study evaluated pollution emissions from pelletized biomass burning, including CH 4 (methane), NMHC (nonmethane hydrocarbon compounds), CO, SO 2 , NO x , PM 2.5 (particulate matter with an aerodynamic diameter ≤2.5 μm), OC (organic carbon), EC (element carbon), PAHs (polycyclic aromatic hydrocarbons), EPFRs (environmentally persistent free radicals), and OP (oxidative potential) of PM 2.5 , and compared with those from raw biomass burning. For most targets, except for SO 2 and NO x , the mass-based emission factors for pelletized biomass were 62-96% lower than those for raw biomass. SO 2 and NO x levels were negatively correlated with other air pollutants ( p < 0.05). Based on real-world daily consumption data, this study estimated that households using pelletized biomass could achieve significant reductions (51-95%) in emissions of CH 4 , NMHC, CO, PM 2.5 , OC, EC, PAHs, and EPFRs compared to those using raw biomass, while the differences in emissions of NO x and SO 2 were statistically insignificant. The reduction rate of benzo(a)pyrene-equivalent emissions was only 16%, much lower than the reduction in the total PAH mass (78%). This is primarily attributed to the more PAHs with high toxic potentials, such as dibenz(a,h)anthracene, in the pelletized biomass emissions. Consequently, impacts on human health associated with PAHs might be overestimated if only the mass of total PAHs was counted. The OP of particles from the pellet burning was also significantly lower than that from raw biomass by 96%. The results suggested that pelletized biomass could be a transitional substitution option that can significantly improve air quality and mitigate human exposure.

In this study, soybean straw pellets (SSP) and pine wood pellets (PWP) were used as materials for torrefaction at 200–350 °C. Impacts of torrefaction temperature on the physicochemical properties, hydrophobicity, and mechanical properties of the pellets were investigated. Results showed that some oxygen-containing functional groups in the biomass pellets disappeared during torrefaction, and the oxygen content significantly decreased. The hydrophobic behavior of biomass is highly affected by their chemical composition. A significant decrease in hemicellulose content was observed in torrefied pellets. Consequently, the equilibrium moisture content of torrefied pellets decreased significantly; and the torrefied PWP remained intact even after immersion of more than 2 h in water. As the torrefaction temperature increased, the cellulose and lignin started to decompose and formed more micropores. Meanwhile, the torrefied pellets became less dense, which lowered the mechanical properties of the pellets. Optimal temperature for the preparation of high-quality torrefied SSP and torrefied PWP was found to be 250 °C and 300 °C, respectively, since higher temperatures cause excessive loss of volatiles and degradation of mechanical properties without significantly enhancing the high heating value of torrefied pellets. [ABSTRACT FROM AUTHOR]

It is very important to determine the amount of mechanical damage to biomass pellets during handling, transportation, and storage. However, it is difficult to determine the amount of damage to biomass pellets caused by existing external forces. However, a useful method is the finite element methods, which can be used in different engineering fields to simulate the posture of the material under defined boundary conditions. In this research, a drop test simulation of biomass pellet samples was performed by using the finite element method. An experimental study (compressive test) was carried out to measure some mechanical properties of the sample and use the obtained data in the finite element method simulation. The stress–strain curve of different biomass pellets was determined. Yield strength, Poisson's ratio, ultimate strength and modulus of elasticity, and stress were identified. In the end, the maximum equivalent stress, highest contact force (generated normal force from target surface at impact), and shape of deformation of samples at impact were obtained from simulation results. The drop scenario was created with 25 steps after the impact site, and the FEM simulation was solved. The maximum stress value was 9.486 MPa, and the maximum generated force was 485.31 N. at step 8 of the FEM simulation. When the stress magnitudes were assessed, simulation outputs indicated that simulation stress values are inconsistent with experimental data. [ABSTRACT FROM AUTHOR]

A wider use of the regional bioenergy resources for the development of environmentally friendly energy production providing microwave pretreatment of lignocellulosic biomass pellets (wood, straw, and peat) of different origin at a frequency of 2.45 GHz is promoted. A hypothesis is proposed and tested that microwave pretreatment of biomass pellets and blending of such pretreated pellets with raw pellets can be applied to enhance the thermochemical conversion of lignocellulosic biomass blends from different origin. The test results confirm that increased reactivity and heating value of pretreated biomass pellets enhances heat energy production and limits the formation of green house gases (GHG) emissions, thus advancing a more efficient usage of agricultural and forestry waste for energy production. [ABSTRACT FROM AUTHOR]

Pyrolysis (Pyr) and hydrothermal carbonization (HTC) of corn stalk (CS) catalyzed with sewage sludge salts were investigated as a comparison of two biomass refining processes to produce char. The influence of the following salt-catalysts (SC)- NH4H2PO4, KH2PO4, Na2HPO4, and CaCl2- on the higher heating value (HHV), char yield (CY), energy yield (EY), and energy densification (ED) as well as an elemental analysis (C, H, N, S, O) of the produced chars were determined. Besides, ATR–FTIR spectra were made from the resulting biochar (BC) and hydrochar (HC). For each processing method, two temperatures were set: HTC 180/210 °C and Pyr 400/500 °C. CS had an HHV of 19 MJ/kg, and the catalyst-free HC and BC came out with 22 MJ/kg. The NH4H2PO4-catalyst demonstrated the maximal efficiency in advancing the HHV for the HTC with 27 MJ/kg (23 MJ/kg for the Pyr), as the Mixed catalysts for the Pyr with 24 MJ/kg, the Pyr-BC increased 2–5 MJ/kg, and the HTC-HC 5–7 MJ/kg. The HC ended up with higher results compared with the BC: HHV 2–3 MJ/kg, CY and EY 5–10%, and ED 0.1–0.2. On the opposite BC marked a higher level of coalification than the HC, the BC came close to that of coal while the HC ranged in the area of peat. Both processing methods were improved by most SC and the Mixed catalysts. Especially the chars of the Mixed SC reached the same carbonization level at lower processing temperature. [ABSTRACT FROM AUTHOR]

The use of residual biomass of forest and/or agricultural origin is an increasingly common issue regarding the incorporation of materials that, until recently, were out of the typical raw material supply chains for the production of biomass pellets, mainly due to the quality constraints that some of these materials present. The need to control the quality of biomass-derived fuels led to the development of standards, such as ENplus®, to define the permitted limits for a set of parameters, such as the ash or alkali metal content. In the present study, samples of vine pruning, and ENplus®- certified pellets were collected and characterized, and the results obtained were compared with the limits presented in the standard. The values presented from vine pruning approximated the values presented by Pinus pinaster wood, the main raw material used in the production of certified pellets in Portugal, except for the values of ash, copper (Cu), and nitrogen (N) contents, with vine pruning being out of the qualifying limits for certification. However, it was found that the incorporation of up to 10% of biomass from vine pruning allowed the fulfillment of the requirements presented in the ENplus® standard, indicating a path for the implementation of circular economy processes in the wine industry. [ABSTRACT FROM AUTHOR]

Green energy produced from waste plastic and wood biomass was an effective way to promote sustainable development. To improve the utilization efficiency of solid waste, a novel porous media co-combustion system of plastic and wood was designed. The combustion characteristics and product concentration of the mixture were investigated for different parameters. The results indicated that the increase of air velocity increased the combustion temperature, and the hydrogen production reached the maximum at v = 12 cm/s. The syngas yield increased first and then decreased with increasing plastic content, and polypropylene (PP) and polyethylene (PE) promoted methane production. Moreover, hydrogen concentration gradually increased with increasing inert bed length. Syngas production increased with increasing plastic size, and the methane concentration of spherical plastics was 242.61% higher than that of Raschig ring plastics. The corresponding research results provided a theoretical reference for the bioenergy utilization of solid waste. [Display omitted] • A co-combustion system was designed for the production of green hydrogen and methane. • The methane concentration increased with the increasing proportion of plastic. • Bed length and filling methods greatly affected temperature distribution and syngas production. • Plastic Raschig rings obtained higher green hydrogen production and heating value. [ABSTRACT FROM AUTHOR]

Biocoke has the potential to reduce the fossil-based materials in metallurgical processes, along with mitigating anthropogenic CO2- and greenhouse gas (GHG) emissions. Reducing those emissions is possible by using bio-based carbon, which is CO2-neutral, as a partial replacement of fossil carbon. In this paper, the effect of adding 5, 10, 15, 30, and 45 wt.% biomass pellets on the reactivity, the physicomechanical, and electrical properties of biocoke was established to assess the possibility of using it as a fuel and reducing agent for a blast furnace (BF) or as a carbon source in a submerged arc furnace (SAF). Biocoke was obtained under laboratory conditions at final coking temperatures of 950 or 1100 °C. Research results indicate that for BF purposes, 5 wt.% biomass additives are the maximum as the reactivity increases and the strength after reaction with CO2 decreases. On the other hand, biocoke’s physicomechanical and electrical properties, obtained at a carbonization temperature of 950 °C, can be considered a promising option for the SAF.

In this present research work, fruit and vegetable waste (FVW) sourced from the commercial market is transformed to solid fuels. Solid biomass fuel for commercial heating is produced using agricultural wastes. This in turn reduces the effect of environmental issues. Enough investigations are seen in the literature for Anacardium occidentale kernels, and no study is seen for materials Brassica oleracea leaves, Moringa oleifera pods, Citrullus lanatus lunds and Annona squamosa seeds and are considered for testing and evaluation in the present study. The amount of moisture contents of residues was dried in rotary drum dryer using sun parabolic dish collector coupled with U-type air heater (1000 W). The dried loose biomasses are powdered into grains (< 50 µm) by crushing. By the application of manual press briquetting machine (800 psi), along with the starch binder (< 10%) the grains are pelleted. Inclusions of starch binder effectively bind the material and provide increased compressive strength, a desired one. The outcome for all the above fuels is in the range of: compression strength (300–450 psi), proximate analysis (< 2% of ash), ultimate analysis (< 2% sulphur), moisture content (< 10%), calorific value (15–18 MJ/kg), bulk density (250–350 kg/m3), resistance to water penetration (70–82%), drop shatter resistance (> 94.5%) and tumbling test (> 95%). Less costs of FVW pellets, for the fuel use in boilers and incinerators, etc., provide as a potential and eco-friendly fuel for energy generation. [ABSTRACT FROM AUTHOR]

Physicochemical properties of biomass pellets were compared following their preparation from extracted and non-extracted sycamore leaves. The goal was to achieve high-quality biomass pellets. Batches of pellets were prepared at different moisture contents and pressure. The properties, including pellet density, diametric compressive strength, and combustion performance, were analyzed. Pellets produced from extracted leaves had higher pellet density (between 1125 and 1250 kg·m-3) compared to those made from non-extracted leaves. In addition, data of the combustion experiment showed more weight loss in extracted leaves’ pellets and a higher burning rate (9.54%·min-1) than that of non-extracted leaves’ pellets (8.47%·min-1). Also, the pellets made from extracted leaves could be ignited and burned easily compared to non-extracted leaves. However, the diametric compressive strength was not always higher in extracted leaves’ pellets compared to non-extracted. In general, it was concluded that extraction could increase the pellet density and improve combustion performance but did not fit the purpose to increase the diametric compressive strength. The analysis and conclusions can provide a reference for the production of high-quality biomass pellets. [ABSTRACT FROM AUTHOR]

The use of residual biomass of forest and/or agricultural origin is an increasingly common issue regarding the incorporation of materials that, until recently, were out of the typical raw material supply chains for the production of biomass pellets, mainly due to the quality constraints that some of these materials present. The need to control the quality of biomass-derived fuels led to the development of standards, such as ENplus®, to define the permitted limits for a set of parameters, such as the ash or alkali metal content. In the present study, samples of vine pruning, and ENplus®-certified pellets were collected and characterized, and the results obtained were compared with the limits presented in the standard. The values presented from vine pruning approximated the values presented by Pinus pinaster wood, the main raw material used in the production of certified pellets in Portugal, except for the values of ash, copper (Cu), and nitrogen (N) contents, with vine pruning being out of the qualifying limits for certification. However, it was found that the incorporation of up to 10% of biomass from vine pruning allowed the fulfillment of the requirements presented in the ENplus® standard, indicating a path for the implementation of circular economy processes in the wine industry.

While the production costs and logistical benefits of biomass pelleting have been widely discussed in the literature, the downstream economic and environmental benefits of processing pelleted biomass have been largely neglected. To investigate those benefits, we performed a comparative techno-economic analysis and life cycle assessment of producing ethanol using loose and pelleted forms of biomass. Analyses of a 2000 metric tons (dry)/d biorefinery showed that using pelleted biomass is more economical than using loose or baled biomass. The lowest minimum ethanol selling price (MESP) for pelleted biomass was USD 0.58/gal less than the lowest MESP for loose biomass. Among all processing conditions analyzed, MESP for ethanol produced with pelleted biomass was always lower than when produced with loose biomass. Shorter pretreatment and hydrolysis times, higher pretreatment solids loadings, lower ammonia requirements, and reduced enzyme loadings were the primary factors contributing to lower MESP with pelleted biomass. Similarly, pelleted biomass also demonstrated a 50% lower life cycle greenhouse gas emission compared to loose biomass. Emissions from higher pelleting energy were offset by downstream advantage in lower chemical needs.

In order to increase the use of a variated raw material base for pellet production with a maintained density level, knowledge of the biomaterials' ability to counteract any springback effects is essential. In this study, the springback effects were investigated for single press produced pellets from cellulose, hemicelluloses, pectin, and two woods at different moisture contents. The change in pellet coloring was also tested through a spectrophotometer for both xylan and carboxymethyl cellulose (CMC) pellets. The results show that the density of xylan pellets is much higher than glucomannan, for both green and cured pellets, and that the length of the pellets, as well as springback contribution, differ between the hemicelluloses. The study also presents results showing that both xylan and CMC pellets have a mutually identical spectrum and that the changes in the structure of xylan are not only related to moisture content, but are also pressure-related. The study also postulates that the color difference of the xylan pellets is a result of physical changes in the structure, as opposed to being of a chemical nature. [ABSTRACT FROM AUTHOR]

[Objective] There are many limiting factors for the fuel used in the tobacco flue-curing process, such as the low precision of temperature and humidity control, thus causing high leaves loss. Therefore, it is necessary to explore a new clean energy to improve the quality and efficiency of flue-curing process and further reduce the labor and energy cost. [Method] This study investigated the differences of the precision of temperature and humidity control, flue-curing cost, the loss of tobacco leaves and economic traits between alcohol-based fuel and biomass pellets energy. [Result] Alcohol-based fuel control of curing barn temperature and humidity was more accurate than the biomass pellets. Moreover, the curing weight loss and curing cost of the middle and upper leaves used alcohol-based fuel were lower 8.93% and 11.71%, 34.50% and 19.79%, respectively than the biomass pellets. Compared to the biomass pellets, the average price in alcohol-based fuel treatment increased by 3.20 and 1.06 yuan/kg, and the ratio of mid-high grade increased by 9.45 and 2.54 percentage points, but the ratio of low grade decreased by 3.39 and 2.53 percentage points, and the ratio of abandoned tobacco leaves decreased by 6.03 percentage points. Stronger chroma and richer oil was found in alcohol-based fuel than the biomass pellets. The other chemical compositions of tobacco used alcohol-based fuel were within the range of high-quality tobacco. [Conclusion] To sum up, the alcohol-based fuels, as a new clean energy, can reduce the loss and cost of flue-curing and improve the quality of tobacco. [ABSTRACT FROM AUTHOR]

The use of charcoal and firewood for cooking is common in Zambia, and its utilization is such that the deforestation rate is high, energy utilization is low, and unfavorable cooking methods lead to high death rates due to indoor air pollution mainly from particulate matter and carbon monoxide. By using an alternative cooking method, such as pellet stoves, it is possible to offer a sustainable solution, provided that sustainable pellet production can be achieved. In this study, 12 different available biomaterials were pelletized in a single pellet unit to investigate their availability as raw materials for pellet production in Zambia. The study showed that sicklebush and pigeon pea generated the same pelleting properties correlated with compression and friction and that both materials showed low moisture uptake. The study also identified two groups of materials that broadened the raw material base and helped to achieve sustainable pellet production. Group 1 consisted of materials with equal pelleting abilities (miombo, peanut shell, pigeon pea, and sicklebush) and Group 2 consisted of materials that showed low impact of varying moisture content (eucalyptus, miombo, peanut shell, pigeon pea, and sicklebush). The hardest pellet was made from Tephrosia, which was followed by Gliricidia. [ABSTRACT FROM AUTHOR]

Abstract This study investigates the potential of cow dung, an animal manure, as a binder to enhance the physicochemical properties of the base pellet (a mixture of wheat straw and rice husk). In the first step, preliminary experiments were performed to select the best composition of wheat straw and rice husk for the base pellet. The selection was based on calorific value. Subsequently, the effect of operating parameters such as varying compositions of cow dung (0–100%), molasses concentration (0–100%) and drying time (12–48 h) was investigated. Thus, Central Composite Design using Response Surface Methodology was used to investigate the proximate analysis, calorific value, bulk density and durability of biomass pellets. The experimental results suggested that the addition of cow dung into the base pellet resulted in the increase of volatile matter, ash content, bulk density and durability of the base pellet. As a result, the maximum calorific value of 14.98 MJ/kg, moisture content of 3.37%, volatile matter of 45.49%, ash content of 31.38%, bulk density of 108990 kg/m3 and durability of 95% were obtained. However, optimization of operating parameters was performed to optimize the ash percentage. With the pellet composition of 8.5% (base pellet composition of 90% wheat straw and 10% rice husk), molasses concentration of 50% and drying time of 12 h, 52% reduction in ash content and 2.3% increase in calorific value were obtained at the cost of 38% reduction in the bulk density and insignificant reduction in durability of the produced pellet. Therefore, the use of waste material like cow dung as a binder can be considered as a sustainable approach to improve the physicochemical properties especially durability of biomass pellets. Thus, it can effectively be used to fulfill the energy and heating requirement of rural areas. Highlights • Utilization of cow dung as binder in pellets composed of wheat straw and rice husk. • Production of pellets with maximum calorific value of 19.13 MJ/kg and 98% durability. • 52% reduction of ash content by optimizing the % composition of rice husk. [ABSTRACT FROM AUTHOR]

In Portugal, some species are now considered invasive by law and have proliferated in recent years. Among these, Acacia dealbata stands out. This work investigated the behavior of this species, in order to characterize and evaluate its potential as raw material for biomass pellets production, while controlling its proliferation. It was found that A. dealbata has a large capacity for raw material supply, as cutting 2 ha resulted in about 140 tons of biomass. Thus, the attribution of a market value for this material could result in a reduction in the area occupied by the invasive species, once the demand for it increases, causing a pressure over the resource. This pressure on the species must be duly followed by other control measures, such as reducing the population and mitigating its proliferation. Laboratory tests have shown that both the raw material and the finished product are similar to those obtained with other species normally used for biomass pellet production, such as Pinus pinaster and Eucalyptus globulus. Thus, it can be concluded that there is a high potential for this species in the production of biomass pellets for energy, and that this may be an important contribution to controlling the proliferation of this invasive species.

Biomass pellets provide a pivotal opportunity in promising energy transition scenarios as a renewable source of energy. A large share of the current utilization of pellets is facilitated by intensive global trade operations. Considering the long distance between the production site and the end-user locations, pellets may face fluctuating storage conditions, resulting in their physical and chemical degradation. We tested the effect of different storage conditions, from freezing temperatures (−19 °C) to high temperature (40 °C) and humidity conditions (85% relative humidity), on the physicochemical properties of untreated and torrefied biomass pellets. Moreover, the effect of sudden changes in the storage conditions on pellet properties was studied by moving the pellets from the freezing to the high temperature and relative humidity conditions and vice versa. The results show that, although storage at one controlled temperature and RH may degrade the pellets, a change in the temperature and relative humidity results in higher degradation in terms of higher moisture uptake and lower mechanical strength.

The binder can improve the physical characteristics of biomass pellets by forming solid bridges and increasing the adhesion of biomass materials. Taking pine sawdust as raw material and brown sugar water with different concentration as a binder, this study adopted spraying and stirring methods, respectively, and mixed brown sugar water with biomass in diverse proportions. The characteristic of pellets such as durability, relaxation ratio and compressive strength were studied by orthogonal design. Through range analysis, BP (Back Propagation) neural network factor significance analysis and mapping the relationship between physical properties and factors according to the importance of each factor, the effect of densification variables on the physical characteristics of biomass pellets was studied, and the outcome of adding brown sugar water binder to raw material by spraying method in improving the densification quality of biomass was explored. Results showed the brown sugar water binder added to pine sawdust by spraying method could mix the binder and biomass raw material more evenly compared with the stirring method. The relaxation ratio of pellets obtained by spraying method was reduced by 13.47%. The optimal densification conditions of pine sawdust were when the compaction pressure was 100 MPa, the mass ratio of brown sugar to water was 2:1, the proportion of brown sugar water to biomass material was 3%, and the adding method was spraying.

To reutilise the hazardous waste material coal tar residue (CTR) to bring environmental and economic benefits, CTR was first used as a binder to prepare biomass pellets with enhanced mechanical strength and heating values. CTR, which mainly contained asphaltenes (40.06%), aliphatics, aromatics and non-hydrocarbon components, had a high viscosity (72,276 mPa·s) and heating value (27.46 MJ/kg). When the CTR percentage increased from 0 to 40 wt%, the abrasive resistance of wheat straw, sawdust and moso bamboo pellets significantly increased from 10.62–69.20% to 95.66–98.24%, while their water resistance time increased from 6 s to >30 min and their heating value increased by 20.62–25.96%. The ignition temperature of wheat straw pellets increased from 275.7 to 280.7 °C as the CTR content increased from 0 to 30 wt%, whereas the maximum burning rate decreased from 1.28 to 0.82 mg/min and the burnout temperature increased from 465.33 to 563.33 °C. [ABSTRACT FROM AUTHOR]

Biomass is renewable clean energy. The aim of this study is to explore the combustion properties and emission characteristics of NOX, SO2, PM, and HCl in the combustion process of biomass pellet fuels. In this study, three kinds of fuels (pine sawdust, mixed wood, and corn straw) were selected to be studied by using a tube furnace to simulate industrial boiler. Experiments were conducted under different combustion conditions (combustion temperature and air flow). The results show that pollutant emissions were related to fuel type, combustion temperature, and air flow. The emissions of NOX were contingent on N content in the fuel and the peak emissions of NOX appeared in the range of 50~600 mg/m3 at 4 L/min and 700℃. The emissions of SO2 were related to combustion condition and close to zero under the condition of sufficient combustion. The emissions of HCl and particulate matter (PM) increase with the rise of temperature, but the emission of PM was minimal at 800℃. Average HCl emission was 0.2~0.5 mg/g under steady-state conditions (4 L/min and 700℃). All in all, the pollutant emissions of biomass pellet fuels during combustion are lower than those of the traditional fuel, and the combustion efficiency is relatively higher. [ABSTRACT FROM AUTHOR]

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Long transport distances and extended storage of biomass pellets especially in humid environments provide a suitable setting for enhanced degradation in the form of moisture sorption, cracking and attrition. We developed an optically transparent, low-cost and environmentally friendly coating to reduce moisture sorption and storage degradation of pellets. The developed coating is a hybrid sol–gel, based on tetraethoxysilane (TEOS) and 3-glycidoxypropyl-trimethoxysilane (GPTMS) precursors. We coated two types of untreated and one type of torrefied wood pellets and stored them in a climate chamber during 1 month simulating a ship's hold, at a constant condition of 40 °C and 85% relative humidity. After 1 month of storage, the mean water contact angle increased by a factor of two compared to the uncoated ones. The lower wettability of the sol-gel coated untreated pellets compared to the non-coated torrefied pellets might provide an alternative to torrefaction. • GPTMS/TEOS sol-gel is compatible with the heterogenous composition of biomass pellets. • The coating offers a sealing function reducing the mean apparent depth of the cracks. • After 1 month of storage, the coated pellets retained their hydrophobic behavior. [ABSTRACT FROM AUTHOR]

In order to increase the use of a variated raw material base for pellet production with a maintained density level, knowledge of the biomaterials’ ability to counteract any springback effects is essential. In this study, the springback effects were investigated for single press produced pellets from cellulose, hemicelluloses, pectin, and two woods at different moisture contents. The change in pellet coloring was also tested through a spectrophotometer for both xylan and carboxymethyl cellulose (CMC) pellets. The results show that the density of xylan pellets is much higher than glucomannan, for both green and cured pellets, and that the length of the pellets, as well as springback contribution, differ between the hemicelluloses. The study also presents results showing that both xylan and CMC pellets have a mutually identical spectrum and that the changes in the structure of xylan are not only related to moisture content, but are also pressure-related. The study also postulates that the color difference of the xylan pellets is a result of physical changes in the structure, as opposed to being of a chemical nature.