Degradation Of Pellets Research Articles

Deep Insight into Reactivity of Li3PS4 Electrolyte for Solid Li-Ion Batteries Towards Humidity Using Large Instruments

Wide commercialization of Li-ion batteries (LIBs) for electric transport stimulates a demand for safer batteries with higher energy density. Thiophosphate solid electrolytes (TSEs) for LIBs are one of the most promising candidates to replace a classical liquid electrolyte with volatile components owing to their high ionic conductivity values and appropriate mechanical properties for processing [1]. However, one of the main drawbacks of TSEs is their high sensitivity towards humidity even in trace amounts. The reactivity with water and moisture impacts the electrochemical properties of the electrolytes and leads to toxic H2S emissions. This aspect plays a crucial role for the choice of LIB manufacturing environment (dry room characteristics) and requires fine understanding of underlying mechanisms to optimize a performance / cost ratio for solid-state batteries (SSBs).In the present study, a unique combination of characterisation methods was applied to investigate the reaction between densified Li3PS4 pellet and different levels of humidity (dew point (DP) -40 °C and DP=12 °C for 15 min and 2 h) from chemical and morphological/microstructural points of view. H2S gas evolution was accurately quantified upon a TSE exposure to humid atmosphere using a home-made flow-through setup with differentiation between surface and bulk pellet reactivity [2]. Further, top-view propagation of Li3PS4 pellet degradation was investigated using SEM and EDX techniques showing fractures generated through gas released leading to some increase in the pellet porosity at DP= -40 °C; apparition of cracks and oxygen content raise in case of DP = 12 °C exposure. The bulk of the exposed pellets was probed using non-destructive X-ray nanotomography (ESRF, ID16b). Different scenarios were observed at low and high levels of humidity during 15 min and 2 h of the pellet exposure (see Fig.). Degradation front containing large pores and cracks propagated up to 50 µm to the depth of the pellet (~400 µm total thickness) after 2 h of exposure to DP= 12 °C. X-ray diffraction-computed tomography (XRD-CT, ESRF, ID15a) was employed to observe structural changes in 3D for Li3PS4 SE upon its reaction with humidity at different depths. Minor changes were find in crystalline structure of Li3PS4 after DP= -40 °C exposure while a reaction at DP=12 °C provoked formation of new phases propagating up to 90 µm depth of the pellet. Some of newly formed compounds were identified, i.e. P2S2O3, Li2HPO3, P2O5 and Li2S2O6.2H2O. Structural strains for Li3PS4 crystalline phase after its exposure to DP=12 °C were revealed thanks to advanced XRD-CT analysis. Finally, the impact of the pellet exposure to humidity at different conditions on its ionic conductivity was investigated.As a result of this study, a solid link was found between the morphological, microstructural, chemical degradation of the TSE and its ionic conductivity upon reaction with water. It was evidenced that the crack formation and propagation to the bulk of TSE pellet is a result of a complex cyclic mechanism, which includes chemical attack of H2O molecules on Li3PS4 pellet surface, creation of mechanical strain for the TSE lattice, formation of solid degradation products and gaseous H2S, crack propagation due to the strain release and the gas evolution, further penetration of water to the bulk of the pellet, etc. To the best of our knowledge, this is a first comprehensive study of reaction between SSE and humidity taking into account all the aspects above. This work contributes to understanding of key triggers for TSE deterioration in contact with different concentrations of water and to definition of proper environment for solid-state batteries production and handling.Beamtime at the ESRF was granted within the Battery Pilot Hub MA4929 “Multi-scale Multi-techniques investigations of Li-ion batteries: towards a European Battery Hub.

Reduction Degradation of Lump, Sinter, and Pellets in Blast Furnace with Hydrogen Injection

Reduction Degradation of Lump, Sinter, and Pellets in Blast Furnace with Hydrogen Injection

Pyrolysis of high-density polyethylene: Degradation behaviors, kinetics, and product characteristics

Pyrolysis is a promising technology for converting plastic waste into valuable raw materials while offering a potential solution to the global plastic pollution crisis. In this study, the thermal pyrolysis of high-density polyethylene (HDPE) is investigated in a drop tube reactor under nearly isothermal conditions. The impact of reaction temperature and gas/volatile residence time on carbon conversion and product distribution is examined across a range of 500–900 °C and 3.6–32.2 s, respectively. Non-condensable gas products detected by online mass spectrometry are H2, CH4, C2H4, C2H6, C3H6, and C3H8. At elevated temperatures and prolonged residence time, H2 yield reaches as high as 8.6 wt% of the initial HDPE mass due to intensified cracking reactions of C2–C3 hydrocarbons and long-chain aliphatic compounds. Consequently, pyrolysis tars consist mainly of polycyclic aromatic hydrocarbons (PAHs) with 5–7 rings, accompanied by visible coke deposition within the reactor. HDPE decomposition to volatiles is an endothermic process and it is complete at a temperature between 492 °C and 525 °C, depending on the heating rate employed, from non-isothermal thermogravimetric analysis and differential scanning calorimetry (TGA-DSC) measurements. The thermal degradation of HDPE pellets follows the two-dimensional nucleation growth model for conversion levels up to 0.8 with an apparent activation energy of 259–270 kJ/mol and a pre-exponential factor of 4.83 × 1017–1.37 × 1019 min−1, determined from various isoconversional methods such as Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), and Starink, along with Criado's master plots. These findings provide valuable insights into optimizing process parameters and refining reactor design for pyrolysis, which can be integrated with gasification and reforming processes to enhance hydrogen production on a larger scale.

Multi-scale thermal degradation of wood pellets under low heating rates: Experiments and modeling

Pyrolysis and combustion experiments were carried out on a single wood pellet in a drop tube furnace, under a heating rate of 5 °C/min. Kinetic modeling was done using the Extended Independent Parallel Reaction model. Three reactions were considered in the pyrolysis case and only one in the combustion case. In the pyrolysis case, a thermal model was proposed which is coupled with the kinetic model to correct the temperature inside the pellet. In the combustion case, the mass rate curve was compared to that of the main gaseous emissions. The mass and mass rate curves between the combustions of a pellet in the drop tube furnace and of pellet sawdust in a thermobalance under the same heating rate were compared.

Hydrostatic pressure impedes the degradation of sinking copepod carcasses and fecal pellets.

Fast-sinking zooplankton carcasses and fecal pellets appear to contribute significantly to the vertical transport of particulate organic carbon (POC), partly because of low temperature that decreases microbial degradation during the descent into the deep ocean. Increasing hydrostatic pressure could further reduce the degradation efficiency of sinking POC, but this effect remains unexplored. Here, the degradation of carcasses and fecal pellets of the abundant marine copepod Calanus finmarchicus was experimentally studied as a function of pressure (0.1-100MPa). Samples were either exposed to elevated pressure in short 1-day incubations or a gradual pressure increase, simulating continuous particle sinking during a 20-day incubation. Both experiments revealed gradual inhibition of microbial respiration in the pressure range of 20-100MPa, corresponding to 2-10-km depth. This suggests that hydrostatic pressure impedes carbon mineralization of fast-sinking carcasses and fecal pellets and enhances the deep-sea deposition rate of zooplankton-derived organic material.

Intertwined synergistic abiotic and biotic degradation of polypropylene pellets in marine mesocosms

The accumulation of plastic waste in the oceans has caused growing concern for its effects on marine life. The interactions of plastics with environmental factors have been linked to fragmentation to micro- and nanoparticles with different properties and consequences, but the mechanism of fragmentation has not been fully understood yet. In this work, we investigate the combined effect of marine communities and ultraviolet (UV) radiation towards the degradation of virgin and artificially weathered polypropylene (PP) pellets after a long-term incubation period in marine mesocosms. The surface chemical alterations and deterioration of the polymer, in conjunction with the attachment and evolution of marine bacterial communities, the development of biofilm and exopolymeric substances (EPS), as well as the colloidal properties (zeta-potential and hydrodynamic diameter) of the mesocosms were studied. The surface area of both types of pellets decreased over time, despite no concrete weight change being observed. Cell growth, EPS production and colloid particle size were correlated to the loss of area. Therefore, we propose that surface area could be effectively monitored, instead of weight loss, as an alternative indicator of polymer degradation in biodegradation experiments. Changes in the chemical structure of the polymer, in addition to the evolution of the biological factors, implied that a complex degradation process alternated between two phases: an abiotic phase, when UV irradiation contributes to the deterioration of the polymer surface layers and a biotic phase, when marine communities degrade the weathered polymer surface to reveal the underlying layer of virgin polymer. Finally, microscopic particles, produced as a result of the decrease in pellet area, promoted the aggregation of colloidal particles. The role and impacts of these colloidal particles in marine ecosystems are yet as unidentified as that of micro- and nano-sized plastic particles and call for further investigation.

Hybrid sol-gel coatings for reducing wettability and storage degradation of biomass pellets

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.

Advanced Assessment of Biomass Materials Degradation in Pneumatic Conveying Systems: Challenges and Applications

In this study, the degradation of wood pellets and dry roasted coffee beans in a pneumatic conveyor was evaluated for high-speed impacts. The change in particle size and generation of fine particles were used as an indicating parameter for the degradation. A four-bends industrial scale conveying system was used for the degradation study in lean phase pneumatic conveying. The effects of operating parameters on the degradation were investigated, including the conveying velocity of particles and particle concentration. The experimental results showed that the degradation and the fines generation increased with an increase in particle velocity. An opposite trend was observed with an increased solid concentration in the pipeline. It was found that the two types of wood pellets traveled at different particle velocities with the same operating conditions, which resulted in significant differences in the degradation. Compared to the wood pellets, roasted coffee beans were found to travel at air velocity. In conclusion, the degradation in a pneumatic conveying system is complex and challenging to evaluate because there are many influential factors, such as the type of materials, equipment, and operation conditions. Early assessments in a laboratory will be beneficial to evaluate the degradation at all controlled operative conditions.

Yellow and Black Soybean Pellet Degradation and Nutrients Hydrolysis During In Vitro Gastrointestinal Digestion

Yellow and Black Soybean Pellet Degradation and Nutrients Hydrolysis During In Vitro Gastrointestinal Digestion

Assessment of Petroleum-Based Plastic and Bioplastics Degradation Using Anaerobic Digestion

Bioplastics have emerged as a viable alternative to traditional petroleum-based plastic (PET). Three of the most common bioplastic polymers are polyhydroxybutyrate-valerate (PHBV), polylactide (PLA), and cellulose-based bioplastic (CBB). This study assessed biodegradation through anaerobic digestion (AD) of these three bioplastics and PET digested with food waste (FW) at mesophilic (35 °C) and thermophilic (55 °C) temperatures. The four plastic types were digested with FW in triplicate batch reactors. Additionally, two blank treatments (inoculum-only) and two PHBV treatments (with FW + inoculum and inoculum-only) were digested at 35 and 55 °C. The PHBV treatment without FW at 35 °C (PHBV-35) produced the most methane (CH4) normalized by the volatile solids (VS) of the bioplastics over the 104-day experimental period (271 mL CH4/g VS). Most bioplastics had more CH4 production than PET when normalized by digester volume or gram substrate added, with the PLA-FW-55 (5.80 m3 CH4/m3), PHBV-FW-55 (2.29 m3 CH4/m3), and PHBV-55 (4.05 m3 CH4/m3) having 848,275 and 561%, respectively, more CH4 production than the PET treatment. The scanning electron microscopy (SEM) showed full degradation of PHBV pellets after AD. The results show that when PHBV is used as bioplastic, it can be degraded with energy production through AD.

Synthesis and Characterization of Nanoporous Biphasic Calcium Phosphate

For the past few years, many researchers are focusing on biomaterials fabrication in porous form. The research on porous calcium phosphate has been investigated due to its excellent biocompatibility and better osseointegration. This research paper presented nanoporous biphasic calcium phosphate (BCP) synthesised using chemical precipitation method. Triblock co-polymer F127 was used as pore directing agent. The chemical compositions of pure BCP samples were examined using X-ray diffraction (XRD) analysis which shows common peak of BCP. The pore size distribution (PSD) on the other hand shows that the pore size of the samples mainly distributed at 52.8 nm, 49.6 nm and 32 nm. BCP pellets were soaked in phosphates buffered saline (PBS) and distilled water (DW) for 15 days. The pH of the soaking medium decreases throughout the soaking period due to degradation of BCP pellets, which release hydrogen ions into the PBS and distilled water. BCP degrades faster in distilled water than in PBS. After soaking for 15 days, materials were examined with a scanning electron microscope (SEM) to assess the morphological structure before and after in vitro degradation. Apatite formation was discovered on the surface of the BCP pellet that had been immersed in the PBS solution.

DEM-CFD simulation of wood pellet degradation by particle-wall impact during pneumatic conveying

A numerical degradation model based on two key-functions, the so-called selection and breakage functions, is developed and implemented into a coupled DEM-CFD approach for investigating wood pellet degradation and fines formation during pneumatic conveying by particle-wall impact. The influence of operating conditions like air flow, product flow and solids loading ratio as well as of pipe component geometry on degradation is examined. Detailed insights into the flow field and particle motion are obtained. The inter-particle and particle-wall collisions are statistically analysed since they are the major cause of particle degradation.Apart from operating conditions, the bend radius is varied in four steps, supplemented by a 90°-Elbow as the worst-case scenario and a straight pipe section for reference. Increasing air flow rates, and thus higher particle velocities, as well as decreasing pellet mass flows and smaller bend radii result in progressive particle degradation. Particle-wall collisions turned out to be the major reason for particle breakage. Numerical results are compared to experimental data and show good agreement.

Spiral Vibration Cooler for Continual Cooling of Biomass Pellets

Cooling is an important process during the production of pellets (as post-treatment). The pellet cooling process significantly impacts the quality of the pellets produced and the systematic use of energy. However, the cooling systems currently in use sometimes encounter technical problems, such as clogging of the perforated grids (sieves), the discharge hopper, or pellet degradation may occur. Therefore, a prototype of a new pellet cooling system using a vibrating feeder was tested. The aim of the study is to present a new variation of pellet cooling system using spiral vibration cooler as a possible solution next to a counterflow cooler. The presented system was tested (critically evaluated and discussed) in two design variants. The first variant consists in cooling by chaotic movement of the pellets. The second is then in combination with the chaotic movement of the pellets together with the action of intense air flow using specially placed air hoses. All tests involved pelletization of rapeseed straw. It was found that both cooling system variants could, realistically, be used. However, the variant with an intense air flow was more energy-intensive, a factor which is, however, offset by the higher quality of the pellets. No negative impact of vibrations to pellets quality was occur. Studies provide insight into new usable technologies that do not reduce the efficiency of the process as a result of grate clogging.

Can habitat type predict the abundance of the European rabbits on oceanic islands?

The European rabbit (Oryctolagus cuniculus) is a key prey species in Mediterranean ecosystems. However, it is also considered a pest on many oceanic islands, even though its true abundance and ecological effects on different island habitats are poorly understood. We present data on rabbit abundance for the best-preserved habitats of the Canary Islands, Spain (National Parks), including ecosystems differing in climate, topography, plant species richness and composition. Three methods of assessing rabbit abundance from faecal pellet density are compared to ascertain the best method to compare highly distinct habitats. The Cleaning method was used during spring, summer, autumn and winter to check whether there were differences in pellet degradation among habitats that could prevent comparisons between them. Rabbit abundance is determined by complex interactions among abiotic and biotic factor. Despite differences in climate conditions, the results obtained for rabbit density with fast methods correlated well with the slow Cleaning method. The Circular method was the most useful to work with for extensive sampling in different habitats. The best models for explaining rabbit density for all habitat types combined included tree cover, abiotic and topographic and climatic variables. Thus, factors influencing rabbit density vary depending on habitat type with Macaronesian laurel forests being the ecosystem least likely to be invaded by rabbits. The present study highlights that rabbits reach damaging densities for plant conservation in most areas on the Canary Islands.

Microstructural degradation during the storage of biomass pellets

The use of biomass pellets as a source of renewable energy has increased in recent times. However, pellet storage during transportation can compromise their properties, due to fluctuating temperature and humid environments. Here, we show that extended storage of one month at 40 °C and 85% relative humidity causes significant biomass pellet degradation. This was evidenced by higher pellet porosity, weight gain, increased inclusion body formation and creation of an internal network of cracks. We quantify the inclusion and pore growth processes at the surface and within the pellets, which has implications for subsequent thermochemical conversion. The global bioenergy transition may depend upon biomass pellets, and this study shows that storage conditions are critical in the supply chain, so to maintain their quality. Without the development of stronger policies to avoid premature degradation of biomass pellets, they may not realize their full potential as a bioenergy source.

Analysis of wood pellet degradation characteristics based on single particle impact tests

The knowledge of size reduction of wood pellets during pneumatic conveying is important to achieve failure-free system operation and to set-up adequate quality assurance processes. In the present study, experiments are performed with a single particle impact test facility. A stereoscopic high-speed camera set allows 3D-particle tracking and visual analysis of the particles' degradation properties. Based on the data obtained, empirical correlations for the statistical description of the pellets' breakage behaviour are presented depending on particle length, impact velocity and collision angle. These relationships are expressed mathematically by two key functions: the so-called selection function (breakage probability) and the breakage function (fragment size distribution). As expected, higher impact velocities lead to more damage, especially at normal collisions (90°) due to the maximum change of momentum. Furthermore, smaller particles tend to be more breakage resistant as they contain less impurities and cracks. Finally, an outlook on the influence of pellet quality and target material on the particles' degradation behaviour is given. Here, pellets with higher durability tend to break at higher impact loads and into larger fragments. In addition, a softer target material (e.g. HDPE) causes less particle breakage than e.g. steel.

The Effect of Biomass Pellet Length, Test Conditions and Torrefaction on Mechanical Durability Characteristics According to ISO Standard 17831-1

With the recent increase in biomass pellet consumption, the mechanical degradation of pellets during transport and handling has become more important. ISO standard 17831-1 is an accepted global standard that is commonly used amongst researchers and industries to determine the mechanical durability of pellets. However, the measured mechanical durability sometimes fails to match the certificate accompanying the shipment. In such cases, pellet length specifications are suspected to play a role. This paper studies the effect of pellet length on mechanical durability for various types of commercially produced biomass pellets. In addition, the effect of test conditions and torrefaction on the mechanical durability of biomass pellets has been investigated. To study the effect of pellet length, pellets were classified into three groups: shorter than 15 mm, 15 to 30 mm, and longer than 30 mm, and their length distributions were measured using an in-house image processing tool. Then, the mechanical durability of pellets was measured using ISO standard 17831-1. The mechanical durability results were compared to random-sized pellet samples. To study the effect of test conditions, the mechanical durability test was operated at different time intervals to elucidate the effect of tumbling at different conditions. The results show that the mechanical durability depends highly on the length distribution of the pellets, with a difference between categories of up to 13%. It was also observed that the mechanical durability remains relatively constant after a specific time interval. Based on the results, we highly recommend modifying the current ISO standard to account for the pellet length distribution (PLD).

Breakage of green iron ore pellets

Mechanical degradation of green iron ore pellets prior to induration is a concern and can result in return of material to discs or drums or contamination of the feed to the induration furnace during pelletization. The work investigates the effects of pellet size, drop height, impact angle and type of surface on the response of pellets to multiple impacts, analyzing not only the critical condition for appearance of a surface crack, but also for their disintegration. It also analyzes the effect of deformation velocity during compression, showing that stiffness of green iron ore pellets remains relatively constant while pellet fracture energies significantly increase. It is observed that the effect of pellet size is limited, while the effects of drop height, velocity, angle and type of surface significantly influence degradation of such pellets. Finally, the effect of weakening due to repeated drops on the strength of pellets after firing is demonstrated.

Comparative investigation on thermal decomposition of powdered and pelletized biomasses: Thermal conversion characteristics and apparent kinetics

In this work, the thermal degradation behaviors of two kinds of biomasses (pinewood and rice husk) with powder and pellet under three oxygen concentrations were investigated by a self-designed macro-thermogravimetric analyzer. An obvious hysteresis of thermal degradation of biomass pellets was observed under three conditions. The maximum activation energy of biomass pellets was significantly greater than that of biomass powders, while their average activation energies were almost equal based on distributed activation energy model. For the oxygen-rich combustion, the comprehensive combustion character index of powdered and pelletized biomasses ranged from 3.92 × 10−7 to 5.16 × 10−7%2·min−2·°C−3 and from 1.82 × 10−7 to 1.91 × 10−7%2·min−2·°C−3, respectively. Furthermore, the derived biochar of powdered biomass has a higher caloricity than that of pelletized biomass during combustion by TG-DSC analysis. The performances of thermal degradation observed by macro-thermogravimetric analyzer could factually reveal the influence of mass and heat transfer on the thermochemical conversion of powdered and pelletized biomasses.

Experimental analysis of wood pellet degradation during pneumatic conveying processes

The size reduction of wood pellets during pneumatic transport in a laboratory test rig is investigated. For the quantification of pellet breakage and attrition, the length distribution of each bulk sample is measured in combination with the gravimetrical determination of the amount of fines before and after every conveying step. In laboratory tests a variation of pipe elements (bend radii, couplings, pipe reducer or cyclone separator), air volume and product mass flows and pellet quality is investigated. Additionally, particle velocities are determined with a stereoscopic high-speed camera set.Results demonstrate the strong dependence of wood pellet degradation on operating conditions and selection of pipe components. Increasing air volume flow and, thus, higher particle velocities induce particle size reduction, whereas increasing pellet mass flow has the opposite effect, although the influence is weak. Increasing pipe length or decreasing bend radius leads to progressive formation of fines.