Content Of Pellets Research Articles

Effect of storage conditions on lignocellulose biofuels properties

This article examines the effects of different storage conditions on selected physicochemical properties of three types of agro-biomass pellets: sunflower husks, wheat straw and hemp hurds, and wood pellets. The tests were carried out in a climatic chamber, which allows simulation of real storage conditions, i.e. conditions with high air humidity and variable (±) ambient air temperatures. The results showed higher degradability of agro-biomass pellets compared to woody biomass. The pellets degraded to a less extent at varying ± temperatures than at high humidity (90% RH). After complete moisture saturation, durability decreases for agro-pellets by an average of 9%, while after freezing and defreezing for sunflower husk pellets and woody pellets durability decreases by 2%, and for hemp hurd pellets by 11%. In contrast, strength-by-dropping index for agro-pellets decreased by 20% after being in the environment (30 °C and 90%RH) and 15% under varying temperature conditions. No change in the energy parameters of all pellets in the dry matter was noted. On the other hand, an increase in the moisture content of pellets when they are stored under different environmental conditions results in a decrease in calorific value.

Interaction of SPI pellets with plasma on JET and associated disruptions

The presented data refer to the Shattered Pellet Injector (SPI) experiments carried out at JET in 2019–2020. This paper is a full journal version of the data originally presented as posters at TMPDM_2020 and EPS_2021. This paper presents various aspects of the interaction of pellets with plasma and associated disruptions. The experiment was performed with I p = (1.1–3.1) MA plasmas and mainly with Ne + D2 pellet composition, but also with Ar pellets. The Current Quench (CQ) time, τ 80−20, is the key characteristic of mitigation effectiveness. A pellet with a high content of Ne or Ar can reduce the CQ duration below the upper required JET threshold. Plasmas with high (thermal + internal poloidal magnetic) pre-disruptive plasma energy require a high content of Ne pellets to obtain a short CQ duration. Pellets with a small amount of Ne (and accordingly large amount of D), instead of causing a mitigated CQ, create the conditions for a ‘cold’ Vertical Displacement Events (VDE). The SPI was applied to plasma with different status: mainly to normal (‘healthy’) plasma, i.e. not prone to disruption, post-disruptive and VDE plasma. This study shows that SPI effectiveness in terms of CQ duration and, accordingly, EM loads does not depend on the state of the plasma, whether it is ‘healthy’ or post-disruptive plasma. SPI has been shown to reduce the axisymmetric vertical vessel reaction forces by about (30–40) % compared to unmitigated disruptions. On JET, the VDE, whether ‘hot’ or ‘cold’, always creates the conditions for a toroidal asymmetry in the plasma, so the VDE on the JET is referred to as Asymmetric VDE (AVDE). The interrupting of VDE and prevention of AVDE with SPI has been demonstrated. Thus, the effectiveness of disruption mitigation using SPI has been confirmed.

Assessment of the Characteristics of Corncobs Used for Energy Needs

Due to environmental pollution and global warming, the use of renewable energy sources such as agricultural residues is gaining attention. Corn is the main source of food in many countries, and after harvesting it, the agricultural and industrial sectors generate significant amounts of residues. This study focused on corncob processing, its preparation, and the evaluation of its characteristics for energy needs. There was no significant difference between drying with active ventilation in the dryer and outdoor drying conditions. The adequate moisture content of corncob pellets is 12.39% at a compression ratio of 3.43 ± 0.011 and a maximum pellet density of 1012.96 ± 3.35 kg m−3. The variation in pellet density at a given adequate moisture content is at least 0.78%. The compression ratio of the pellets compacted on the horizontal matrix granulator is 9.75% higher than that of the pellets produced on the laboratory automatic press. The corncob’s lower calorific value was 17.35 ± 0.14 MJ kg−1, and the ash content was 1.78 ± 0.24%. The produced pellets are strong enough and can be used for combustion. This research may help to better understand the properties of corncobs and their energy potential.

Characterizing value-added pellets obtained from blends of miscanthus, corn stover, and switchgrass

The current pellet industry primarily relies on woody biomass. Inclusion of a diverse feedstock, such as herbaceous biomass, is necessary to meet the rising demand for pellets in heat and power generation, and for biofuel production. This study was motivated by the need to densify biomass, improving its naturally low energy density, to reach the required pellet standards for biofuel conversion. We developed value-added miscanthus pellets blended with different ratios of corn stover and switchgrass and analyzed their chemical, physical, and mechanical properties. Pure miscanthus pellet durability index (PDI) was less than 85 %, well below the ISO 17225-6 standard for herbaceous pellets. While increasing switchgrass and corn stover ratios increases durability beyond 94 %, it also increases ash content from 1.6 % to 4.6 %, a quality unfavorable for biofuel conversion. The moisture content of the blended pellets varied from 7.12 % to 12.45 %, and positively correlated with the durability of the pellets. Pure miscanthus pellets had the highest bulk density, 633 kg/m3, while pellets containing 75 % miscanthus and 25 % corn stover had the lowest density, 564 kg/m3. The findings of this study also identified a decrease in the pellet bulk density with the increase in ash content and pellet diameter.

Development and Characterization of Pectin-Based Colon Targeted Pellets Containing Lactobacillus Plantarum FNCC-0461

Lactobacillus plantarum FNCC-0461 is a lactic acid bacteria isolated from "dadih" a traditional Indonesian food that has potential as a probiotic. Probiotics can show health benefits if they can maintain cell viability of at least 7 log CFU in the distal ileum and colon. However, most probiotics are not resistant to the extreme conditions of the gastrointestinal tract. Probiotic encapsulation in the form of pectin-based colon targeted pellets is a promising delivery system to overcome probiotic viability problems due to the gastrointestinal tract extreme conditions and can assist release to specific target site in colon. Pellets was produced by extrusion-spheronization method using microcrystalline cellulose (MCC), lactose and pectin. Optimization of spheronization process was carried out by varying the spheronization speed and time while the optimization of pellets formula was carried out by varying the concentration of total pectin and the type of coating polymer (cellulose acetate phthalate (CAP) or shellac). The morphology, particle size, moisture content, micromeritic properties, process yield and viability of pellets were evaluated. Release of probiotics on coated and uncoated pellets were examined at pH 1.2, 6.8 and 7.4 under simulated colon fluid for 24 hours. The formula containing MCC, lactose and pectin (5:4:1) with spheronization speed at 1500 rpm for 15 minutes showed the best pellets characteristic and cell viability. The pellets obtained were spherical, with particle size distribution of 913.57±8.28 μm, process yield of 88.71±1.04 % and viability of 7.50 x 107 cfu/g. Pellets coated with CAP showed the highest cell release in simulated colon fluid of 1.38 x 107 CFU/g at 24 hours. This research proved that CAP coated pellet formulation has promising potential for colon targeted delivery of L. plantarum as well as to protect the viability of probiotics for colon-targeted delivery.

An investigation into the utility of eastern barn owl pellet content as a tool to monitor small mammal diversity in an arid ecosystem

AbstractConsidering several logistical limitations associated with live trapping in arid environments, owl pellet analysis provides a potentially useful alternative to estimate small mammal diversity. Owl pellet analysis has been used to estimate local small mammal diversity under the assumption that the method can reliably reflect the composition of local small mammal assemblages. However, the validity of owl pellet contents for use in ecological assessments has not been established. Thus, the present study aimed to determine the potential for eastern barn owl (Tyto delicatula) pellet analysis to improve the monitoring of small mammals in arid Australia. We analysed two ecological datasets from Pilungah Reserve on the northern boundary of the Simpson Desert in central Australia to assess their effectiveness for detecting expected small mammal species: 250 owl pellets collected from a known roosting site and 5 years of small mammal records from historical, long‐term trapping surveys. Species composition and detection probability of mammals varied depending on the method used. Owl pellet analysis returned higher species richness overall, while traditional trapping methods indicated a higher probability of detecting certain mammal species (e.g., the wongai ningaui Ningaui ridei, brush‐tailed mulgara Dasycercus blythi and the hairy‐footed dunnart Sminthopsis hirtipes). Importantly, analysis of owl pellets revealed two mammal species that had never been detected at the study site (dusky hopping mouse Notomys fuscus and Carpentarian false antechinus Pseudantechinus cf. mimulus). We suggest that owl pellet analysis could be particularly valuable when used as a precursor or in concert with traditional trapping to monitor and assist in the conservation of small mammal species in arid environments.

Karakterisasi Pelet Pupuk Organik Berbahan Eco Enzyme

Eco enzyme has nutrients for liquid organic fertilizer. However, the eco enzyme's N, P, K elements are still below the quality standard. Liquid organic fertilizer is disadvantaged in handling, packaging, use, and transportation compared to pellet form. Nutrient levels can be increased through fish bones and rice bran addition. This research aims to determine the characteristics of the best pellets based on Ministry of Agriculture quality standards No. 261/2019, such as length, diameter, density, water content and N, P, K levels. The eco enzyme, water, fish bones, and rice bran’s formula were: C1 (1: 0: 1: 1), C2 ( ¾: ¼: 1: 1 ), and C3 ( ½: ½: 1: 1). Pellets were made by mixing the ingredients with 5% tapioca solution. The tools used to measure pellet length, diameter, and pH were caliper and pH meter. The water content using the gravimetric method. The N, P, and K levels were tested at BALISTA Lembang, Bandung. All formulations’ pellet length and diameter averaged ±12 mm and 4 mm. Water content of C1, C2, and C3 pellets were 8.63%, 8.97%, and 9.18%, respectively. pH of C1, C2, and C3 pellets were 5.7, 5.8, and 5.9, respectively. Particle density for C1, C2, and C3 were 1.37 g/cm3, 1.44 g/cm3, and 1.46 g/cm3, respectively, while the bulk densities were 0.58 g/cm3, 0.63 g/cm3, and 0.64 g/cm3, respectively. The N, P, K levels in C1, C2, and C3 were 5.2%, 4.79% and 4.3%, respectively. C3 is the best formulation. All pellets meet quality standards.

Cracking the Code: Process Parameter Effects on Khaya senegalensis Energy Pellet Moisture Content

The production of energy pellets from biomass sources holds immense potential for sustainable renewable energy generation. This study investigates the influence of key process parameters on the moisture content of energy pellets derived from Khaya senegalensis, a promising biomass feedstock in Malaysia. With a focus on unlocking the relationship between process variables and pellet moisture, a systematic experimental approach was adopted. The objective of this study is to investigate the effects of raw material moisture, feedstock particle size, compression pressure, and pelletization temperature on the manufactured biomass energy pellet's moisture content. By employing a comprehensive design of experiments and statistical analysis, the nuanced effects of these parameters are revealed on the moisture content of Khaya senegalensis energy pellets. The results illuminate the complex interplay between these process variables and the final moisture characteristics of the pellets. Understanding how these parameters impact moisture content is crucial for optimizing pellet quality, combustion efficiency, and storage stability. The study found a quadratic relationship between particle size, compression pressure, and pelletization temperature, indicating that larger particle sizes correlate with higher moisture content. Excessive pressure led to elevated levels while increasing temperature showed a decreasing trend. This research contributes valuable insights that advance the knowledge frontier of biomass pelletization, paving the way for enhanced utilization of Khaya senegalensis as a renewable energy resource.

Lignin Use in Enhancing the Properties of Willow Pellets

Shrub willow (Salix spp.) is an emerging lignocellulosic biomass utilized in fuel pellets as an energy source. However, improvements are needed to increase the efficacy of pellets in areas such as the energy content, durability, and hazardous carbon monoxide emissions. This study examined the effect of utilizing lignin as an additive on willow pellet properties. Two types of lignin were used in individual treatments: lignin recovered from the hot water extraction of willow (RecL) and commercial softwood kraft lignin (ComL). A statistical analysis of the ash content, energy content, bulk density, durability, pellet length, moisture absorption, and carbon monoxide emissions for the pellets with and without the addition of RecL or ComL lignin was conducted. The observed significant reduction in carbon monoxide emissions from RecL pellets was an important effect of the lignin addition. There were also significant increases in the energy content, bulk density, and durability of lignin-added pellets. While the production of carbon monoxide via pellets continues to be explored, lignin can be utilized as an additive to reduce carbon monoxide emissions and simultaneously improve other pellet properties.

Near-infrared light therapy ameliorates depression-induced intestinal dysfunction in rats possibly by activating PGC-1α/Nrf2 signaling and increasing hippocampal BDNF expression

To investigate the effect of near-infrared (NIR) light therapy on depression-induced intestinal dysfunction in rats and explore the possible mechanism. Thirty-two male SD rats were randomly divided into control group, model group, low-dose NIR light group and high-dose NIR light group. All the rats except for those in the control group were subjected to chronic restrained stress (CRS) for 4 weeks, and NIR light therapy of the head was administered in the two NIR light groups. The depression- like behaviors, intestinal functions, fecal water content and number of fecal pellets of the rats were evaluated. HE staining was used for detecting histopathological changes in the hippocampus and colon, and hippocampal expressions of BDNF, Nrf2 and PGC-1α were detected with Western blotting. The rats in the CRS model group showed significantly increased immobility time and visceral sensitivity in the behavioral tests, decreased fecal pellets and fecal water content, and lowered expressions of BDNF, Nrf2, and PGC-1α in the hippocampus (P<0.05). Histopathological examination of the CRS rats revealed loosely arranged hippocampal pyramidal cells, obvious neuronal damages, and obvious inflammatory cell infiltration in the colon with irregularly arranged mucosal glands and a high pathological score. High-dose NIR light therapy significantly lowered the immobility time and visceral sensitivity, increased the number of fecal pellets and fecal water content (P<0.05), and enhanced hippocampal expressions of BDNF, Nrf2, and PGC-1α (P<0.05) of the depressive rats. The rats receiving high-dose NIR light therapy also exhibited close arrangement of the hippocampal pyramidal cells with significantly reduced neuronal damage and colonic inflammatory cell infiltration, neatly arranged mucosal glands, and lowered pathological score. NIR light therapy can significantly improve depression-like behavior and intestinal function in rats possibly by ameliorating oxidative stress via the PGC-1α/Nrf2 signaling pathway and increasing BDNF level in the hippocampus.

Influence of powder properties and mixing technique under different conditions, on the densification and thermal conductivity of AlN for solar thermal applications

In this study, a novel approach is presented which can be utilized to enhance the thermal conductivity and densification of sintered AlN pellets. AlN pellets with a CaO additive were produced by spark plasma sintering. The influence of CaO powder properties such as particle size (micron-, submicron- and nano-scale), dispersion, flowability and structural characteristics, on the mixing behavior of AlN and CaO mixed powders, and on the porosity and thermal conductivity of AlN pellets, were investigated. Additionally, the influence of mixing conditions, including additive content and rotational speed in a novel high-shear mixer (Picomix), were studied and various mixing techniques were compared. The results indicate that when the CaO content of the AlN pellets is increased to 3 wt%, their thermal conductivity rises from 48.1 W/m·K to 112.9 W/m·K. This increase can be attributed to the formation of a liquid phase, and to a reduction in pellet porosity during sintering. Furthermore, when the rotational speed of the mixer is increased to 5000 rpm, the pellets’ thermal conductivity further rises to 126.2 W/m·K. This improvement is a result of the enhanced dispersion of CaO in the mixed powder. The shearing forces in the Picomix facilitate the coating of AlN particles with submicron- or nano-scale CaO particles, thereby improving the flowability of the mixed powder and narrowing the particle size distribution. This further improves the liquid phase distribution, thus enhancing the thermal conductivity of the AlN pellets (135.3 W/m·K). The novel high-shear mixer (Picomix) has demonstrated enhanced performance when compared with traditional mixing techniques (ball milling and manual mixing), since it involves a solvent-free process, is faster, has a lower energy consumption, causes less powder-oxidation and leads to a higher value of thermal conductivity, making it an excellent choice for the preparation of mixed powders for solar thermal applications.

현장적용을 위한 목재펠릿의 함수율 및 내구성에 대한 간이시험법 평가

현장적용을 위한 목재펠릿의 함수율 및 내구성에 대한 간이시험법 평가

Osteological material and the population state of the speckled ground squirrel (Spermophilus suslicus) on the periphery of the species’ distribution (Belarus)

The studies were carried out in 2021 near the village of Yushevichi, Nesvizh Raion, Minsk Oblast (Belarus). The content of pellets of three bird species were analysed: Buteo buteo, Buteo lagopus, and Corvus corax. In total, 129 intact and about 30 destructed pellets were processed. Skeletal elements of five small mammal species belonging to five genera of two orders (Rodentia and Eulipotyphla) were found, including remains of nine speckled ground squirrels. The remains of seven of the nine ground squirrel individuals found in the pellets were found in raven pellets, however, the authors believe that this fact does not yet prove a greater influence of the raven on the local ground squirrel population. The pellets analysis and observations of feeding behaviour of the three bird species prove that the speckled ground squirrel is constantly included in the diet of both diurnal birds of prey (genus Buteo) and of atypical predators with a mixed nutrition (raven). Finding of intact skulls of Spermophilus suslicus in pellets of the mentioned bird species is unlikely, which is determined by its considerable size. This circumstance does not allow obtaining most of the craniometric characters, but does not prevent the detection of pathomorphological changes. To compare the craniological characters, we used the skulls of dead ground squirrels (n = 5) found in the field near the village of Yushevichi. These individuals had visible injuries (lacerated wounds, etc.) presumably left both by predators and fights between ground squirrels. The most striking pathomorphological changes were revealed: osteoporosis and osteolysis of dental alveoli of the upper and lower jaws and initial osteomyelitis of the cranial vault (in the parietal and frontal bones). We believe that the speckled ground squirrel’s conservation status should be raised to at least Category II (according to the system of categories adopted in Belarus) for the following reasons: over the past six years, out of 12 known colonies, only four colonies have survived, two of which are practically unviable; stable for 10 years reduction in the number; and range fragmentation (single localities). According to the IUCN classification, it corresponds to category CR (critically endangered).

Statistical optimization, characterization and effect of process variables on cotton stalk pellets using tractor drive pelleting machine.

In present study, the development, production, characterization and economic analysis of pellets made from cotton stalk in a tractor PTO-based pelleting machine are investigated. The cotton stalk is widely available in the southern part of India and has a huge potential in bioenergy generation due to its salient physicochemical composition. Many regions of Southern India are suffering from an electricity shortage, and therefore to overcome on this issue, an energy-efficient, portable, tractor PTO-operated pelleting machine was developed that can be operated directly on the field to reduce the transportation cost of agro-residues. The Box-Behnken design using response surface methodology (RSM) was employed to evaluate the performance of the pelleting machine. Based on the ANOVA results, the pelleting efficiency, pelleting capacity, bulk density of pellet and fuel consumption were obtained to be 87.06%, 42.65kg/h, 614.09kg/m3 and 1.12 lit/h, respectively. In order to examine the physicochemical properties of cotton stalk pellets, the proximate, ultimate, physical, TG-DTG, FTIR and SEM analysis have been carried out. As a result, the ash content, calorific value, shattered index and durability of cotton stalk pellets were found to be around 2.73%, 18.92MJ/kg, 92.80% and 93.75%, respectively. A combustion characteristic of pellets using TGA analysis exhibited a maximum mass loss (43.5%) observed in between 180 and 350°C due to the degradation of cellulose and hemicellulose, whereas a SEM analysis of cotton pellets justified its homogeneous morphology along with rich concentration of minerals. The benefit-cost ratio and payback period of developed tractor PTO-operated pelleting machine for cotton stalk were found to be 1.11 and 33.1months, respectively. The internal return of rate was observed to be 74%.

Pore structure characteristics, mechanical properties, and freeze–thaw resistance of vegetation-pervious concrete with unsintered sludge pellets

To make full use of municipal solid waste, the sludge was used to make unsintered sludge pellets. Then unsintered sludge pellets was used to make vegetation-pervious concrete. The effects of the sludge pellet content and the water-to-cement ratio (W/C) on the pore structure characteristics, mechanical properties, ecological properties, and freeze–thaw resistance of the concrete were investigated. The results show that sludge is suitable for preparing pellets due to its good plasticity and high SiO2 and Al2O3 content. A 1:2:1 gypsum/fly ash/lime curing agent is selected to cure unsintered sludge pellets. The total porosity, hydraulic conductivity, ecological properties, and freeze–thaw resistance of the pervious concrete improve with an increase in the sludge pellet content and W/C, while its compressive and flexural strengths decrease. The plant roots penetrate the pervious concrete slab and maintain normal growth after 30 days of germination. In addition, a model considering the effective porosity and mean pore size is proposed for predicting the pore channel tortuosity of pervious concrete. The Kozeny–Carman model for calculating the hydraulic conductivity of pervious concrete is then modified based on the established calculation model of pore channel tortuosity. A model is also developed for predicting the compressive and flexural strength of pervious concrete based on its total porosity and mean pore size. In addition, the mechanism for the freeze–thaw resistance of pervious concrete is analyzed according to hydrostatic pressure. This research explains the full utilization of municipal solid waste materials and guides further research into the properties associated with pervious concrete.

Valorization of Wood-Based Waste from Grapevine

This article deals with the possibility of valorizing wood waste from grapevine cultivation of the varieties Pesecká leánka (white graft) and Frankovka modrá (red graft), grown in Slovakia. From the point of view of chemical composition, two methods (water and ethyl alcohol) were performed for the determination of extractives, acid-insoluble (Klason) lignin, and structural carbohydrates, and FTIR spectra of the grape samples were recorded. Mechanical strength, compression test parallel to the grain, and morphological properties (fiber length, width, and shape factor using a fiber tester) were carried out. The energy potential of grapevines was evaluated by determining the calorific value. According to the results, the relatively high content of carbohydrates (54.19%–55.27%) provides a prerequisite for acid or enzymatic hydrolysis to produce monosaccharides or second-generation bioethanol. FTIR spectra confirmed the higher content of lignin and cellulose in red grapes. The compression strength of grape cuttings (37.34 MPa—red; 32.34 MPa—white) was comparable to the strength of softwood species; hence, these wastes can be used for particleboard or fiberboard production. Average fiber length is comparable to non-wood species; thus, grape cutting can be used for pulp and paper production. The calorific value of grape cuttings ranged from 18.68 MJ·kg−1 (white) to 18.91 MJ·kg−1 (red), with pellets having 16.96 MJ·kg−1. The energetic potential of grape cuttings was comparable to that of other wooden materials; on the other hand, the ash content of pellets from grape cuttings (10.54%) greatly exceeded the limit given by the EN ISO 17225-1 standard, which is a significant disadvantage to pellets used for heating.

Characteristics of Bio Pellets from Spent Coffee Grounds and Pinewood Charcoal Based on Composition and Grinding Method

One type of biomass that has promising potential for bio pellet production is spent coffee grounds (SCGs). However, previous studies have shown that SCGs in bio pellets cause a lot of smoke. Therefore, they need to be mixed with a material that has a higher calorific value to produce better quality pellets. One material that can be used is pine wood because it has a natural resin content that can increase the calorific value. The aim of this study was to examine the quality of bio pellets produced with SCGs and pine wood charcoal at different particle sizes. The charcoal was ground using either a hammer mill (HM) or a ball mill (BM). Pine wood charcoal was mixed with SCGs at ratios of SCGs to pine wood charcoal of 4:6 and 6:4 by weight, respectively, and the adhesive used a tapioca with a composition ratio 5% of the raw material. The bio pellets were produced using a manual pellet press. The quality of the bio pellets was assessed based on Indonesian National Standard (SNI) 8021-2014, and the physical observations include flame length, burning rate, and compressive strength. The average water content, ash content, and calorific value of the bio pellets were in accordance with SNI 8021-2014, but the density and ash content values were below the standard values. The BM variation of bio pellets had a higher compressive strength than the HM variation, and the 4:6 BM variation had the longest burning time compared with 4:6 HM.

Mechanism of magnetite iron ore concentrate morphology affecting the pellet induration process

The effect and mechanism of magnetite concentrate morphology on the quality of indurated pellets were investigated. Concentrates with different morphologies were prepared using high-pressure grinding rolls (HPGR) and ball mill (BM) grinding techniques. Then pelletizing and induration process is done in the temperature range of 800 to 1300 °C. With similar specific surface area for both BM and HPGR concentrates, the morphology of HPGR concentrate had a broad particle size distribution with a high aspect ratio for particles. Results showed that the porosity and FeO content of indurated HPGR and BM pellets decreased with increasing temperature while their cold compressive strength (CCS) increased. However, the porosity and FeO content of HPGR pellets were lower than BM pellets. Also, the CCS of indurated HPGR pellets at temperatures above 1100 °C was significantly higher than BM pellets. Microstructural analysis was performed on concentrate powder, fracture surface, and cross-section of pellets to analyze the mechanism of morphological influences. It was found that the irregular shape and broad particle size distribution of HPGR particles improved the CCS of HPGR pellets due to the improved sintering, increased interlocking force, longer crack propagation path, formation of the uniform liquid phase distribution, and decreased the pellet porosity.

Production of water-permeable ceramic bricks derived from fly ash via a simple pellet method: Mechanism of mechanical strength and permeability

• Water-permeable ceramic bricks were prepared from fly ash via a simple pellet method. • The consumption of fly ash in the ceramic brick was up to 80 wt%. • Average pore size of water-permeable ceramic bricks reached 123.9 μm. • Anorthite phases generated at high temperature contributed to strength of bricks. • The water-permeable ceramic bricks had a low heavy metal leaching toxicity. Rising with the sponge city construction, water-permeable bricks as emerging materials, are receiving more and more attentions. It is a beneficial way to produce water-permeable bricks using industrial solid wastes as raw materials, which could not only eliminate the adverse effect of solid wastes, but also produce sustainable products. Herein, water-permeable ceramic bricks were produced by recycling fly ash as the main material with consumption up to 80 wt% via a simple pellet method. Fly ash was firstly mixed evenly with tailings at a mass ratio of 4:1 to adjust plasticity to prepare pellets. Pellets were then pressed under low forming pressure to obtain raw bricks, which were dried and sintered at high temperature to prepare water-permeable ceramic bricks. Effects of size and water content of pellets, forming pressure, and sintering temperature on the performance of water-permeable ceramic bricks were investigated. Under optimized conditions, ceramic bricks with compressive strength of 48.6 MPa, bending strength of 6.1 MPa and water permeability of 2.83 × 10 -2 cm/s were produced. Average pore size of optimized bricks reached 123.9 μm, which guaranteed excellent water permeability. The generated anorthite phases at high temperature contributed to the high mechanical strength of water-permeable bricks. The evaluation of heavy metal leaching toxicity indicated that the prepared bricks were environmentally-friendly. This study provides a strategy to produce water-permeable ceramic bricks derived from industrial solid wastes.

Cypress Wood and Bark Residues Chemical Characterization and Utilization as Fuel Pellets Feedstock

In order to meet the growing demand for raw material of solid biofuels, it is imperative to find alternative materials of low cost, underutilized so far. In this study, wood and bark material of two common cypress species (Mediterranean and Arizona cypress) were chemically characterized through gravimetric and spectroscopic (FTIR) analyses, to assess their potential to be used as raw materials in the production of fuel pellets. Low bark concentrations (0%, 2%, and 7%) were applied, and the mixtures were densified in a flat-die pellet press. The produced pellets were examined in terms of thermal, physical, hygroscopic, and mechanical properties, using standard ISO17225 thresholds as benchmark. The results revealed that the effect of bark presence in low content οn pellet properties and quality was positive. The ash content of both wood species is adequately low for biofuels production, whereas their bark cannot be purely used as feedstock due to the high ash content. By using low bark contents (2% or 7%), the ash content of pellets was kept adequately low to be categorized in the highest quality classes (A1 and A2: for residential applications), while the produced pellets demonstrated improved dimensional stability, mechanical durability, and slightly improved calorific value. The moisture content, dimensions, and bulk density of all the produced pellet categories fulfilled the standard requirements. Even though the pellets of 2% bark share presented much lower ash contents, only the pellets of 7% bark share were proven to have considerably improved mechanical durability, suitable for residential use. The chemical composition of raw materials (especially the extractives and holocellulose) plays a major role in the mechanical durability of pellets.