Pellet Material Research Articles

Kinetic analysis on low‐temperature oxidation of wood pellets by isothermal microcalorimetry

AbstractLow‐temperature chemical oxidation is the major driver of self‐heating during storage of wood pellets and its kinetics is essential to describe the heat evolution. In the present work, isothermal microcalorimetry was used to characterize heat generation behavior of three types of wood pellets (pine, fir, and redwood pellets) at 30–70°C. The obtained data were employed to derive the kinetics of low‐temperature oxidation by the peak power, iso‐conversional method, and non‐steady analysis. The consistency and applicability of the kinetics derived by the three methods were evaluated. Kinetic parameters determined by the peak power method were observed to match those from the iso‐conversional method at lower conversions of the oxidation for heat generation. The kinetics derived by the iso‐conversional method indicated the oxidation reactivity generally decreasing and activation energy increasing with the conversion because of O2 consumption and reaction mechanism changing. With the impact of O2 consumption considered separately, the kinetics from the non‐steady analysis is capable of describing the evolution of heat power with the conversion and also consistent with that from the peak power method in describing intrinsic reactivity of pellet materials. The kinetics from the peak power and iso‐conversional methods lump the impact of O2 concentration with the reaction reactivity, suggesting their applications requiring additional models for connecting with O2 consumption.

Desulfurization Behavior of Magnetite Pellets Reduced by Isothermal Pure Hydrogen

The desulfurization behavior of magnetite pellets reduced by pure hydrogen at isothermal temperature is studied, the mechanism of self‐oxidation desulfurization is put forward, and the thermodynamic theoretical calculation and experimental verification of this mechanism are carried out. The feasibility of the reaction between iron sulfide and Fe3O4 is analyzed by HSC Chemistry 6.0 software. Additionally, a thermal gravimetric analyzer is used to further study the thermal behavior of pellet material under Ar atmosphere from 400 to 1400 K. The results show that the removal of sulfur in the isothermal reduction process of pure hydrogen does not depend on hydrogen phase diffusion and reduction temperature. During the heating process, self‐oxidation desulfurization occurs in the system, and the self‐desulfurization reaction is more inclined to Fe3O4 + FexSy → FeS + SO2. Under the experimental conditions, the temperature range of self‐oxidation desulfurization under conventional thermal field and microwave field is 700–1100 and 370–1140 K, respectively, and the desulfurization rate is 92.9% and 95.8%, respectively. The key to improving desulfurization by microwave radiation is that iron sulfide has good wave‐absorbing characteristics.

Utilization of Agricultural Waste as a Total Mixed Ratio Pellet Material for Rex Rabbit Feed

This study aimed to evaluate the quality of Total Mixed Ration (TMR) pellets derived from agricultural waste and assess their potential as feed for Rex rabbits. The research employed an experimental approach, utilizing agricultural and plantation waste to produce TMR pellets. The study was conducted in two stages: pellet production and rabbit feeding trials. Three formulations of TMR pellets were developed with varying concentrations of oil palm empty fruit bunches (EFB): P1 (5% EFB), P2 (10% EFB), and P3 (15% EFB). The optimal formulation was subsequently used for the feeding trials. Rabbit feed treatments included T0 (60% commercial pellet + 40% forage), T1 (40% commercial pellet + 20% TMR pellet + 40% forage), T2 (30% commercial pellet + 30% TMR pellet + 40% forage), and T3 (60% TMR pellet + 40% forage). Results from the pellet analysis indicated no significant differences in organoleptic properties among the formulations. The durability test yielded the highest value of 98.77%, while the proximate analysis of the P1 formulation showed a dry matter content of 85.67%, ash content of 10.35%, organic matter of 89.65%, crude protein of 18.65%, crude fat of 18.72%, and crude fiber of 19.18%. In the rabbit feeding trials, there were no significant differences in rabbit performance when compared to those fed with commercial pellets. Based on these findings, it can be concluded that agricultural waste can be effectively utilized as a raw material for rabbit feed pellets, offering comparable quality to commercial alternatives. This research highlights the potential of agricultural waste in reducing environmental pollution while providing an economically viable alternative for animal feed.

Waloryzacja pozostałości rolniczych na pelety w zrównoważonej biogospodarce o obiegu zamkniętym

It is a truism by now that the combustion of fossil fuels has execaerbated climate change, and its repercussions. Biomass in pelletised form, will emerge as substitutes, in the circular bioeconomies of the future. This brief review focuses on the utilisation of agricultural residues as raw materials for pellets, and explores the aspects of sustainability – socio-cultural, economic, environmental, and techno-functional – in the 20-plus peer-reviewed articles selected for that purpose using Scopus with a set of search-phrases. The articles are case studies dated between 2012 to 2023, tracing their provenance to different countries in the world – Brazil, Canada, China, Denmark, Greece, India, Italy, Mexico, Peru, Spain, Thailand, Türkiye, Zambia, etc. Among the many gleanings which are reported in this review, some deserve mention here in the abstract. The social aspect of sustainability has not been studied as much as the economic and environmental. The case studies emphasize the importance of adapting the pelleting process to the properties of the agricultural/horticultural residues and the prevalent local conditions. It is encouraging to note that there is a surfeit of agricultural residues (corn, coffee, quinoa, beans, oats, wheat, olives, tomatoes, pomegranates, grapes, etc. in the articles reviewed) which can be valorised to pellets, also in combination with the in-vogue forestry wastes. This is more advisable if the status quo is open burning of such residues in the fields. The journey towards the sustainable development goals (SDGs) will be aided by investments in such biorefinery-projects, SDG 17 is extremely vital for their success – collaboration and cooperation among several stakeholders around the world. This review, though based on only 20-plus articles from around the world, is an in-depth analysis which promises to be of interest to decision-makers and sustainability-specialists keen on contributing to the transition to a circular bioeconomy.

Optimizing production conditions of innovative bio-pellets developed from flax straw

The increasing global demand for sustainable energy has prompted the utilization of agricultural residues as viable alternatives to traditional fossil fuels. This study specifically focuses on the utilization of flax straw, a substantial by-product in Canadian agriculture, to produce innovative biofuels through the process of pelletization. To enhance the quality of the pellets, lignin extracted from flax straw was introduced as a novel and natural pellet binder. A comprehensive investigation was conducted to analyze effect of various parameters, including flax straw particle size, binder (lignin) content, moisture levels, and pelletization conditions on quality of produced pellets. It was observed that at a compressive force of 4000 N and a die temperature of 95 °C, pellets made from larger flax straw particles (300–355 µm) exhibited a density of 1016 kg/m³ and a mechanical durability of 26.4 %. Subsequently, by reducing the particle size to 75–106 µm, a marked enhancement in both density (1072 kg/m³) and durability (86.1 %, a 2.3-fold increase) was achieved. The incorporation of 10 % lignin into medium-sized flax straw particles (150–212 µm) increased pellet durability by 18.6 % from 73.5 % to 87.2 %. Introducing an optimal moisture content of 14 % to the flax straw resulted in a notable increase in both density (from 1036 to 1154 kg/m³) and durability (from 73.5 % to 90.6 %, a 23.3 % increase). Compressive force and die temperature positively affected pellet quality. Elevating the temperature from 75 to 115 °C in pellets made from 150 to 212 µm flax straw, modified with 10 % lignin and 14 % moisture content, led to a significant improvement in both density (1179 kg/m³) and durability (96.6 %, a 11.9 % increase). Physiochemical characteristics of flax straw, lignin, and the resulting pellets were explored using various techniques such as Fourier transform infrared, thermogravimetric analysis, and differential scanning calorimetry. These comprehensive investigations offer valuable insights for optimizing pellet materials and pelletization conditions and promoting the sustainable utilization of agricultural residues for bioenergy production.

Key fuel characteristics and techno-economic aspects of torrefied rubberwood biomass pellets produced by incorporating various cassava-based binders at varied doses.

Improving energy content and hydrophobic nature of woody biomass can be pursued through torrefaction. This gives torrefied biomass with a low bulk density, potentially increasing storage and transport costs. To overcome this issue, densifying the torrefied biomass is necessary. However, poor binding of particles makes densification challenging without using a binder. Therefore, the aim of this study was to investigate the physicochemical characteristics and techno-economic aspects of torrefied rubberwood biomass (TRWB) when pelletized using various cassava-based binders at different blending ratios. The selected binders included cassava starch (CS), cassava pulp (CP), and cassava chip (CC). Each binder at 5%, 10%, or 15% (wt.) was mixed with TRWB and water before pelletizing using a flat die machine. The results revealed that pelletizing TRWB with different cassava-based binders at various blending ratios influenced the physicochemical characteristics of the TRWB pellets, particularly dimensions, bulk density, fuel and atomic ratios, and energy content. The TRWB pellets demonstrated energy densities in the range of 7.95-11.39 GJ/m3, and their mechanical durability and fine content fell within acceptable ranges. The TRWB pellets maintained their shape during 120min of water soaking, with water absorption levels varying by binder dose. The pelletizing ability, material, and energy costs of TRWB pellets depend on binder type and dose. CP can be applied as a binder for pelletizing torrefied rubberwood biomass. However, the mechanical durability of the product needs to be above the user requirement or standard.

Parallel expansion of a fuel pellet plasmoid

The problem of the assimilation of a cryogenic fuel pellet injected into a hot plasma is considered. Due to the transparency to ambient particles of the plasmoid, the localised region of high-density plasma created by ionisation of the ablated pellet material, electrons reach a ‘quasiequilibrium’ (QE) state which is characterised by a steady-state on the fastest collisional time scale. The simplified electron kinetic equation of the QE state is solved. Taking a velocity moment of the higher-order electron kinetic equation, which is valid on the expansion time scale, permits a fluid closure, yielding an evolution equation for the macroscopic parameters describing the QE distribution function. In contrast to the Braginskii equations, the closure does not require that electrons have a short mean free path compared with the size of density perturbations, and permits an anisotropic and highly non-Maxwellian distribution function. As the QE distribution function accounts for both trapped and passing electrons, the self-consistent electric potential that causes the expansion can be properly described, in contrast to earlier models of pellet plasmoid expansion with an unbounded potential. The plasmoid expansion is simulated using both a Vlasov model and a cold-fluid model for the ions. During the expansion plasmoid ions and electrons obtain nearly equal amounts of energy; as hot ambient electrons provide this energy in the form of collisional heating of plasmoid electrons, the expansion of a pellet plasmoid is expected to be a potent mechanism for the transfer of energy from electrons to ions on a time scale shorter than that of ion–electron thermalisation.

Safety factor diagnostic for tokamak core plasma from three-dimensional reconstruction of pellet ablation trail.

Using a stereo camera system, a new diagnostic for the safety factor of the core plasma based on the pellet ablation trail is applied on the Experimental Advanced Superconducting Tokamak (EAST). In EAST discharge No. 128 874, a shattered pellet injection system is applied to inject a shattered neon pellet into the EAST. Since the strong magnetic field in tokamaks binds the ablated pellet material, the orientation of the pellet ablation trail is the same as the local magnetic field direction. Thus, from the three-dimensional reconstruction result of the pellet ablation trail, the local safety factor q can be obtained. The motional Stark effect (MSE) diagnostic is applied to determine the safety factor q profile in this shot. The determined safety factor q results for this new diagnostic are in quantitative agreement with those from the MSE diagnostic with the mean relative difference of only 6.8%, confirming the effectiveness of this new diagnostic of the safety factor.

Acceleration of cryogenic pellets for Shattered Pellet Injection

Shattered Pellet Injection (SPI) is considered as a method to effectively mitigate the effect of severe disruptions in tokamaks. For the development of SPI technology in ITER, the Centre for Energy Research, in collaboration with H-ion Kft and VTMT Kft, designed, constructed and operates a Disruption Mitigation System (DMS) Support Laboratory. To simulate pellet acceleration, we developed a zero-dimensional model. The model uses the parameters of pellet material, propellant gas characteristics, dimension of the barrel and fast valve (FV), opening characteristics, temperature, and filling pressure of the FV in order to calculate the time dependent pellet position, pellet velocity, FV pressure and barrel pressure during the acceleration process. The goal of the acceleration model is to forecast velocities for parameters where no data is available as of yet. This paper describes the model and compares its results to two significantly different setups: the SPI measurements at the ASDEX Upgrade test laboratory and the ITER DMS Support Laboratory. We show that our model is capable of predicting tendencies and revealing the sticking stress of pellets to the barrel.

Effect of Thermal Activation on the Mineralogical Structure of Magnesium Slag

Magnesium slag's production process is similar to the Portland cement production process. The raw material used is carbonate-containing dolomite, and is calcined in a rotary kiln at 850-900 oC. Afterwards, ferrosilicon and fluorite raw materials are added to the calcined material, they are ground together and turned into pellets, and then they are reduced at a temperature close to the firing temperature of Portland cement clinker (1250-1350 oC) to obtain crown magnesium and magnesium slag. The reduction time of pellet material in reduction furnaces is 12 hours. During this period, almost all of the magnesium minerals in the mixture material are reduced and taken as crown magnesium metal. The remaining material, described as magnesium production slag (reduction furnace waste), consists of Alite (C3S), Belite (C2S), Celite (C3A) and C4AF minerals contained in Portland cement clinker. Some of the minerals contained in Portland cement clinker in the rotary kiln are formed at temperatures below 1400 °C, which is the clinker firing temperature. The only difference other than the firing temperature is that after the Portland cement clinker is fired in the rotary kiln, the clinker is cooled rapidly, increasing the alite (C3S) crystals formed in its structure and preventing the alite minerals from turning back into belite (C2S) minerals. This study produced magnesium slags at different temperatures (1200-1350 oC) by thermal activation method in an industrial environment. The Bogue and XRD methods calculated the mineral phase amounts of the products produced.

Удосконалення процесу фільтрування залізорудного магнетитового концентрату ПРАТ «ЦГЗК» для забезпечення фабрики огрудкування сировиною для DRI обкотишів

Удосконалення процесу фільтрування залізорудного магнетитового концентрату ПРАТ «ЦГЗК» для забезпечення фабрики огрудкування сировиною для DRI обкотишів

Circular material use in landscape design

The aim of the article is to highlight trends in landscape and environmental improvement by including new environmental and landscape elements made from recycled materials. To achieve this objective, a number of objectives have been defined: to present a recycled tyre pellet material for use in outdoor landscaping, to look at the tyre recycling process and how this material is obtained, to look at and analyse market trends and products for this material, how this material fits into the circular economy, to propose new ways of using this material in environmental and landscape landscaping. The methods used in the research are literature analysis, research of examples of good practice in Europe, constructive criticism and analysis, public surveys and grapho-analytical compilation of the obtained data. An essential part of the research is the conducted experiment, as the result of that recycled tire granules were used in outdoor furniture collection. The selected research topic is actual because it is necessary to think about the wider use of recycled tire materials, to increase the use of recycled material in various outdoor environmental products, to create demand in this sector; as well as introduce more people to this material - in a different way than usual.

Observation of local density increase during pellet homogenization on EAST

By combining the X-mode polarized lower and upper cut-off reflections obtained from the density profile reflectometer, we have successfully attained a comprehensive density profile spanning from the edge to the core region in pellet injection (PI) experiments on EAST. During the homogenization process after PI on EAST, an innovative method was introduced to quantify the local density increase. This approach employed the distinctive ‘dual-reflection’ phenomenon observed in the EAST microwave reflectometer, encompassing measurements of both the X-mode lower and upper cut-off frequencies. Furthermore, experimental investigations were carried out on EAST to comprehensively explore the parallel and poloidal expansion of the high-density pellet cloud. Notably, this study marks the first instance of measuring expansion velocities of pellet materials in both parallel and poloidal directions on EAST. A comparative analysis was performed initially between these experimental measurements and simulation results obtained from the HPI2 code, marking a pivotal stride towards enhancing its applicability in EAST.

Utilization of Floating Sludge (Oil and Fat) in The Meat Processing Industry as Raw Material for Catfish Pellets

One of the meat processing industries in Jombang Regency produces a significant amount of floating sludge waste (oil and fat) in its grease trap unit. If proper waste management is not carried out, environmental issues can arise. This article explores the potential use of floating sludge waste from meat processing industries as a raw material for catfish feed, with the aim of reducing waste, improving the economy, and reducing the production costs of catfish farming. Therefore, this research aims to analyze the best nutritional combination for catfish feed made from waste from the meat processing industry, tofu dregs, organic vegetables, and discarded eggs. The method used is fermentation with EM4 and sugarcane molasses, along with the addition of other waste materials to enhance the nutritional quality of the feed produced. There are five variations of feed compositions analyzed using proximate analysis and compared with SNI 01-4087-2006 concerning Quality Requirements for Dumbo Catfish Feed. The results show that several combinations of ingredients can meet most of the catfish feed quality standards, with the best option is K3 feed that made from floating sludge and discarded egg waste. Although, protein content is still below the standard, this combination has the potential to reduce the cost of catfish farming. This article encourages the development of sustainable, environmentally friendly alternative feeds and the potential reduction of industrial waste.

Optical roughness calculation for material structural analysis of energy structure applications under dc plasma processes

Surface qualities make aluminium a low-DC plasma interaction candidate. Aluminum for energy system structure building is studied experimentally, with observations obtained. Aluminum is cheap and frequently utilized in aerospace applications. The selection of materials for new applications of thermonuclear fusion energy, such as Tokamak reactor walls and fusion-based spaceship thrust structures, is important to decide in the design phase. In this study, an experimental setup application is created with low DC-type He plasma ions processed on aluminium pellet surfaces. The physical changes of the aluminium pellet material as an example of an energy structure surface are analysed under a scanned array microscope and 3D surface plots to detect optical roughness attributes.

Optical roughness calculation for material structural analysis of energy structure applications under dc plasma processes

Surface qualities make aluminium a low-DC plasma interaction candidate. Aluminum for energy system structure building is studied experimentally, with observations obtained. Aluminum is cheap and frequently utilized in aerospace applications. The selection of materials for new applications of thermonuclear fusion energy, such as Tokamak reactor walls and fusion-based spaceship thrust structures, is important to decide in the design phase. In this study, an experimental setup application is created with low DC-type He plasma ions processed on aluminium pellet surfaces. The physical changes of the aluminium pellet material as an example of an energy structure surface are analysed under a scanned array microscope and 3D surface plots to detect optical roughness attributes.

Owl-mediated diploendozoochorous seed dispersal increases dispersal distance and supports seedling establishment

Seed dispersal is an essential process contributing to the maintenance of plant populations. Zoochory is a widespread way of plant dispersal in every terrestrial ecosystem that can ensure the long-distance dispersal of seeds. Secondary seed dispersal (SSD) by far-ranging raptors is a special type of zoochory, which might have a role in colonizing new habitats. We used the barn owl (Tyto alba) as model species to test the effectivity and seasonality of SSD in open semi-natural landscapes. We collected 582 pellets from six sites in East-Hungary throughout one year. We identified prey items in the pellets and determined the viable seed content of the pellets by germination experiments. We found that herbivorous Microtus arvalis L. was the most abundant prey item through which most of the seeds spread. Owls dispersed the seeds of generalist and disturbance-tolerant plants, indicating the habitat type where small mammals occur abundantly. In another experiment we tested the effect of the pellet material on the seedling survival and found that prey remains enhanced establishment of seedlings. Our study suggests that SSD by barn owl is occasional but important event in long-distance seed dispersal. Since the studied owl species uses several habitat types and has larger mobility than the rodents, the revealed dispersal mechanism can considerably increase seed dispersal distance and seed exchange between habitat types.

Potential and Characteristic of Biomass Pellet from Tea Plantation Wastes as Renewable Energy Alternative

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. Keywords: Biomass pellets; Green circular economy; Renewable energy; Tea plantation waste; Wood pellets

Numerical simulation of mechanical interaction between pellet and zircaloy-4 cladding under reactivity-initiated accident conditions

Reactivity-initiated accident (RIA) is one of the accidents considered by fuel safety criteria. The power pulse caused abrupt expansion of the pellet, leading to pellet and cladding mechanical interaction (PCMI). Cladding ductility is gradually decreased in the process of oxidation and hydrogen uptake during irradiation. As a result, the extrusion of the pellet to the cladding causes the cladding to produce greater hoop stress and hoop strain, which leads to damage. A simulation of PCMI using ABAQUS was designed to analyze cladding mechanic properties. By comparing the calculation results of the simulation scheme with the data obtained in the reactor experiment, it is proved that the simulation calculation results are in good agreement with the experimental data in the reactor, and the rationality of the simulation scheme is verified. Based on the out-pile mandrel equipment simulated PCMI, the corresponding finite element model was established to study related test parameters.By analyzing the results of the simulation calculation outside the reactor, it is found that the pellet material, cladding temperature, compression rate, tensile load, friction coefficient and the cladding hoop stress and hoop strain have a certain relationship: (1) The choice of pellet material affects the reactor. The overall law of hoop stress-strain in the external simulation results basically has no effect. (2) The temperature of the cladding has effect on the hoop stress peak. (3) The compression rate has effect on the time for the cladding to reach the hoop peak stress. (4) Tensile load will affect the starting position of the hoop stress-strain of the cladding. (5) The friction coefficient has a significant influence on the stress and strain trend of the cladding. The outside experiment can be carried out more effectively, and it can provide guidance and a basis for the outside experiment.

Feasibility of Pellet Material Incorporating Anti-Stripping Emulsifier and Slaked Lime for Pothole Restoration

Climate change has caused a surge in abnormal weather patterns, leading to a rise in cracks, plastic deformation, and pothole damage on road surfaces. In order to fabricate a ready-mix admixture of warm asphalt mixture (WMA) for pothole restoration, this study aimed to develop a neutralized anti-stripping material in pellet form by extruding a combination of slaked lime and a liquid emulsifier additive. Slaked lime (1% by weight of aggregate) was chosen for its ability to enhance moisture resistance, while a liquid emulsifier (wax + vegetable oil + surfactant + water) was added to create a pellet-type stripping inhibitor for WMA. After successfully fabricating the pellet admixture, this study evaluated the performance of two asphalt mixtures: conventional Slaked Lime Hot Mix Asphalt (LHMA) and the Pellet-Type Anti-Stripping Warm Mix Asphalt (PWMA). Several compatibility tests were conducted to evaluate the quality of the developed material. The results showed that the fatigue resistance of the developed material (PWMA) improved by over 20%, indicating an extended fatigue life for the pavement. The LHMA and PWMA met the quality standard for asphalt mixtures, with a TSR value of approximately 83%. Both mixtures demonstrated improved rutting resistance compared to HMA. The PWMA required 16,500 cycles, while the LHMA required 19,650 cycles to reach a settlement of 20 mm, indicating better moisture resistance than the control mix (13,481 cycles). The modified mixture performed properly in the Cantabro test, with loss rates below 20%, indicating their ability to retain their aggregate structure. The PWMA also showed superior resistance to plastic deformation, with a 12.5% lower phase angle (35°) at a reduced frequency of 10−3. In general, the application of PWMA not only prolongs the pavement lifespan but also reduces the production temperature by over 20 °C, leading to lower emissions and energy consumption. This makes it an environmentally friendly option for pavement applications and contributes to sustainable road construction practices.