Pellet Quality Research Articles

Energy consumption optimization model and system for the pellet drying process of straight grate

The drying process is a crucial stage in the thermal treatment of iron ore pellets in a straight grate, as it has a direct impact on pellet quality and energy consumption. Consequently, this paper develops a simulation model for the pellet bed drying process, which is validated through industrial data and enables the visualization of temperature and moisture distribution within the pellet bed. Based on the simulation model, an optimization model for the drying process is developed to minimize the specific energy consumption per tonne of green pellets. The constraints of the drying process are the moisture content requirements and burst temperature. A genetic algorithm is employed to optimize the parameters such as trolley speed, pellet bed thickness, air temperature, and air pressure. The results show that, with an absolute error criterion of 10 °C, the temperature calculation accuracy of the simulation model exceeds 86%, effectively describing the drying process in a straight grate sintering machine. Under yield limitations, the optimal cumulative energy consumption per tonne of green pellet is reduced by 1.50% during the drying process. Finally, a simulation and optimization system for the drying process in the straight grate is implemented in C++. This system not only generates essential data for designing the drying section in a straight grate but also lays a theoretical foundation for system optimization and optimal control.

Effects of feed conditioning temperature on pellet quality, growth performance, intestinal development and blood parameters of geese from 1 to 28 d of age

A 28-d experiment was conducted to investigate the effects of feed-conditioning temperature on the pellet quality, growth performance, intestinal development, and blood parameters of geese. A total of 180 one-day-old White Yuzhou goslings were randomly allotted to 5 treatment groups, with 6 replicates containing 6 birds each. Five diets were conditioned at 65, 70, 75, 80, and 85°C. Body weight and feed intake per pen basis were recorded from the arrival to the end of the trial. Blood and small intestine samples were collected on d 28 for analysis. The results showed that the pellet durability index (PDI), pellet hardness, and gelatinisation degree of starch (GDS) increased with increasing conditioning temperature (P < 0.05). The final body weight (FBW), average daily gain (ADG) and average daily feed intake (ADFI) of goslings significantly increased when conditioning temperature increased from 65 or 70°C to 80 or 85°C (P < 0.05), accompanied by unaffected feed conversion ratio (FCR) (P > 0.05). The villus height to crypt depth ratio (VH/CD) in the duodenum and ileum improved with increasing conditioning temperature (P < 0.05). Additionally, trypsin and amylase activity were enhanced when the conditioning temperature increased from 65 to 85°C (P < 0.05). No significant differences in the carcass traits and blood parameters of goslings were observed among the groups (P > 0.05). Overall, under the present experimental conditions, increasing the steam-conditioning temperature of pelleted feed improved pellet quality, growth performance, intestinal morphology, and digestive enzyme activity in goslings. Based on broken-line regression analysis, the lower critical conditioning temperature for ADG in geese from 1 to 28 d of age was 80.95°C.

Quality of black pellets of charcoal fines produced with different moisture content and drying time

Charcoal fines are co-products of the wood carbonization process, unwanted because they reduce the gravimetric yield of the main product, charcoal. It can be produced due to the carbonization process, during the storage and transport of charcoal. Pelletizing charcoal fines increases the energy density of this material, producing a homogeneous fuel with lower moisture content, enabling burning in equipment with high energy efficiency, in addition to desirable properties in energy products such as high fixed carbon content and low moisture content. This study evaluated the effect of moisture content and drying time on the production of black pellets from charcoal fines bound with rice starch (Oryza sativa) on the physicochemical and mechanical characteristics. Black pellets were produced using two proportions of water (10 or 20%) and a drying time of 4 or 6 hours. Black pellets were evaluated for their proximate analysis, elemental composition, moisture content, size, apparent density, calorific value and energy density. The addition of water did not affect the content of volatile matter, ash, and fixed carbon, while the treatment with addition of 20% water and four hours of drying showed a higher moisture content (3.34%). The addition of water allowed for better heat conduction and particle arrangement, producing pellets with a durability greater than 98%. The better arrangement promoted by the addition of 20% water also increased the density of the pellets, resulting in greater energy density. Black pellets can be considered an alternative for residential heating, with T3 treatment (20% - 4h) with a high energy density and better performance in terms of desirable properties for use and commercialization according to the standard EN 14961-6.

Synthesis and Characterization of Indigofera Zollingeriana Plant-Based Ruminant Feed Using EM 4 Fermentation Method

This study aimed to produce ruminant feed pellets using Indigofera zollingeriana as the main ingredient, along with coconut pulp, rice bran, molasses, cassava, and EM 4 as additional components. The objective was to investigate the impact of optimizing animal feed pellets made from Indigofera zollingeriana and various mixed ingredients, such as rice bran, coconut pulp, cassava, molasses, and EM 4, by using the EM 4 fermentation method on the physical, mechanical, and chemical properties of the animal feed pellets. The animal feed was prepared by blending Indigofera zollingeriana, coconut pulp, rice bran, and cassava in the proportion of (55.81% : 22.1% : 14.73% : 7.365%), along with molasses and EM 4 in a 1:1 ratio. The test samples were produced by weighing, pulverizing, mixing, fermenting, drying, and molding into pellets. The findings showed that the animal feed pellets made with Indigofera zollingeriana plant concentrate had physical properties that did not meet the standard values, such as specific gravity (1.96 gr/mL), porosity (8.84%), water absorption (68.76%), maturity temperature (38ºC), and solubility in water (4.36%). However, the animal feed pellets had a brownish color and a normal smell, similar to other animal feeds. In terms of mechanical properties, the values for hardness (5.002%) and brittleness (1.53%) met the standard values for animal feed pellets. Regarding chemical properties based on proximate analysis, the animal feed contained 8.22% protein, 6.78% total fat, 26.4% crude fiber, 17.4% carbohydrates, 7.50% ash content, and 33.7% moisture content. Only the ash content met the SNI 3148-2:2017 standard. Thus, the quality of these animal feed pellets needs improvement.

Physicochemical quality of rice bran pellets using different binder materials

Physicochemical quality of rice bran pellets using different binder materials

Quality assessment of biomass pellets available on the market; example from Poland

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

STUDY ON PREPARATION TECHNOLOGY OF HIGH-QUALITY BIOMASS FUEL PELLETS USING CARAGANA KORSHINSKII KOM. POWDER

Caragana korshinskii Kom. powder was used as the experimental material and wheat bran as the binder to produce high-quality biomass molding fuel (BMF) pellets. A series of experiments involving pellet production were conducted in different molding temperatures and at different moisture contents with different percentage of wheat bran by a newly-developed pelletizer using a die heating production method. The biomass molding process was optimized by single factor and orthogonal test with the fuel relaxation density, mechanical durability and molding pressure as indexes. The experimental results showed that the optimum moisture content was 20% by mass percentage of wheat bran is 9% by mass and molding temperature is 140°C in order to get the best quality of high-strength BMF pellets with relative low molding pressure.

Effect of wheat coarseness and pellet quality on performance and particle size preference of broiler chickens fed diets based on wheat and maize

Recent broiler experiments have demonstrated that the macrostructure defined as the diameter and length of pellets can be larger, and that the tolerance for fines in the diet is higher than currently assumed. In a first experiment, broiler performance till 10 d of age was not affected when a 3 mm pelleted diet was replaced with a 5 mm pelleted and crumbled diet (35% particles > 3.6 mm). Preference tests indicated either no particle size preference, or a preference for particles > 2.8 mm. In a second experiment, reducing pellet quality of 5 mm pellets to increase the amount of fines had no effect on weight gain and FCR from 10 to 34 d of age, but when diets consisted of finely ground wheat as compared to coarsely ground wheat, the feed intake was higher and FCR was poorer. When offered feed with particles > 4.0 mm, 2.8 – 4.0 mm, 1.6 – 2.8 mm and < 1.6 mm, broilers ate more particles 1.6 – 2.8 mm than > 4.0 mm at 12 d of age, while no clear particle size preferences were observed at older ages. These data confirm that diets pelleted through a 5 mm die can be used even from day-old, and that broilers can handle a moderate reduction in pellet quality of 5 mm pellets without compromising performance. A high versatility of broiler chickens to particle size variations, and a preference for larger particles than currently assumed even at a very young age, may explain these results.

Paecilomyces variotii (PEKILO®) in novel feeds for Atlantic salmon: Effects on pellet quality, growth performance, gut health, and nutrient digestibility and utilization

Filamentous fungi have potential as an alternative protein source for use in aquafeeds due to their high protein content and bioactive components. Paecilomyces variotii (PEKILO® mycoprotein) is a β-glucan- and nucleotide-rich filamentous fungi with a crude protein (CP) content of 60–70%. A 9-week feeding trial was conducted to evaluate the effects of P. variotii in diets for Atlantic salmon (initial average body weight of 24 g fish−1) reared in freshwater. Four experimental diets were formulated. Diet 1 was a control diet based on fish meal, soy protein concentrate, and wheat gluten meal. Diets 2, 3, and 4 were formulated so that P. variotii replaced 5, 10, and 20% of the CP content of the diets, respectively. Results showed that dietary inclusion of P. variotii was associated with changes in physical pellet quality, including significant linear (p < 0.0001) and/or quadratic (p < 0.01) decreases in pellet length, width, expansion, and durability. Conversely, significant linear (p < 0.0001) and quadratic (p < 0.025) increases in water activity, bulk density, and water stability index were associated with increasing replacement of the CP content of the diets with P. variotii. There were no significant differences in weight gain, growth rate or feed intake among fish fed the experimental diets (p > 0.05), but a significant linear improvement (p < 0.025) in feed conversion ratio (FCR) with increasing dietary inclusion of P. variotii was observed. The apparent digestibility coefficients for CP and gross energy of the experimental diets decreased linearly (p < 0.01) with increasing dietary levels of P. variotii. Similar results were observed for the essential and non-essential amino acids. Despite reduced digestibility, linear increases in nitrogen (p < 0.01), energy (p < 0.025), and mineral (p < 0.001) retention efficiencies were associated with increasing dietary levels of P. variotii. In the distal intestine, dietary inclusion of P. variotii resulted in significant (p < 0.05) upregulation of several cytokines (ifng, il10, and tgfb), effector molecules (inos, arg1, sod), and transcription factors (irf4), suggesting both activation and control of the inflammatory response in this key mucosa-associated lymphoid tissue. Overall, replacement of 20% of the CP content of the diet with P. variotii reduced digestibility of the experimental diets, but did not affect growth performance and improved FCR and nutrient utilization efficiency of salmon. Thus, P. variotii is a promising ingredient with potential for use in salmonid aquafeeds to improve fish performance and health.

Prediction of extruded aquafeed physical quality parameters through a dough viscosity model

AbstractA widely used dough viscosity model in food extrusion was adopted and employed for the analysis and prediction of extruded aquafeed physical quality parameters. The data for the analysis were collected from previously published articles. The analysis was based on the assumption that pellet physical quality parameters, such as bulk density, oil adsorption, hardness, and durability, are correlated to the dough viscosity property changes in the extrusion process. The physical qualities of feed were modeled using the modified viscosity model. The model was evaluated using the data collected from experiments conducted in three different pilot extrusion systems. The results showed that the new model has the capability to predict the physical quality parameters of extruded aquafeed pellets in the three studied scenarios. The absolute average deviations of the model regression for the pellet qualities were 8.5% for hardness, 4.8% for bulk density, 6.5% for oil adsorption, 15.7% for Holmen durability, and 0.7% for pellet diameter. The new model can correlate the physical qualities of aquafeed pellets across different recipes, extruder configurations, and systems.Practical ApplicationsFood or aquatic feed extrusion process operation heavily depends on the operator's experiences and is still a black‐box process. In this study, a dough viscosity model was applied to explain the relationship between extrusion variables and extruded pellet physical qualities. The new model can be used for a quantitative description of a feed formulation extrusion process and feed pellet quality optimization.

Properties of RDF after Prolonged Storage

Increasing production of municipal solid waste (MSW) drives the need for its disposal in a manner that is safe for the environment and human health. However, this may require short- or long-term storage before it can be properly processed. Similarly, a way of processing waste material is necessary for the re-cultivation of dump sites. This article presents the results of an investigation into the effects of long-term open-air storage upon waste material to be turned into refuse-derived fuel (RDF) by standard methods for the assessment of MSW and RDF pellet quality including bomb calorimetry, sieve analysis, furnace drying/burning for water/ash content assessment, and pellet expansion measurements. Results of the investigation indicate that such a form of storage bears no notable negative effect on the quality of the material; the pellet expansion coefficient, heat of combustion, and ash content were all found to be approximate to pre-storage values, with positive implications for the storage of solid waste and the prospects of its subsequent processing into solid fuel. It is shown that such material can be stored in open-air conditions for prolonged periods without the loss of desired parameters. In addition, a discussion of differences between the properties of material drawn from varying depths of the pile is provided and the potential impact of the findings in the context of the production and the storage of refuse-derived fuel is assessed.

Enhancing herbaceous biomass pellets quality by blending with woody biomass and plastic additives, and post-pelletization torrefaction and optimization processes: A review

Enhancing herbaceous biomass pellets quality by blending with woody biomass and plastic additives, and post-pelletization torrefaction and optimization processes: A review

QUALITY OF PELLETS FROM OLIVE GROVE RESIDUAL BIOMASS

Two of the main environmental problems that man currently faces are the high rate of waste generation and energy consumption, both bearing directly upon climate change. The situation requires a change in waste management models, with a greater focus on waste reduction, recycling and appraisal, as well as a change in energy models. This signifies the use of renewable energy sources to supply part of the future demands of fossil fuel. Such sources include biomass sources from agricultural waste. Southern Spain has a large supply of biomass of a residual nature from agricultural activities, such as olive pruning. However, the use of pellets made from olive tree leaves or a mixture of different parts of olive trees is not as yet widespread. This research shows that the use of different types of raw materials from olive grove residues results in pellets with different physical and chemical properties, which define their possible application. More research is needed to design the production of pellets, which will have properties suitable for specific applications and which will possess the quality that satisfies accepted standards and norms.

The Effect of Bakery Waste Addition on Pine Sawdust Pelletization and Pellet Quality

This paper presents research findings on the pelleting process of pine sawdust using bakery waste in a pelletizer. The addition of bakery waste (white wheat–rye bread, whole-grain rye bread, and pumpkin bread) to pine sawdust had a beneficial effect on the kinetic strength of the pellets obtained, an increase of up to approximately three percentage points. The density of pellets with the addition of bakery waste also increased, while the bulk density of the pellets decreased. The addition of bakery waste also had a positive effect on the power demand of the pelletizer. It was reduced from 3.08% (at a 10% addition of white wheat–rye bread) to 22.18% (at a 20% addition of pumpkin bread), compared to the process of compacting pure pine sawdust. In addition, all the pellets containing bakery waste had a lower energy yield (EY) determined based on lower heating value and energy inputs. This index was lower by 53 Wh·kg−1 for pine sawdust pellets with a 10% addition of pumpkin bread. The greatest reduction, on the other hand, was by 173 Wh·kg−1 for pellets, with a 20% addition of white wheat–rye bread. In each case, an increase in the share of bakery additives resulted in a decrease in the energy yield from the pellets obtained. The smallest reduction in EY was found when pumpkin bread was used as an additive (from 53 to 133 Wh·kg−1). Considering all the parameters analyzed characterizing the pellets obtained, it was concluded that the addition of bakery residues to pelletized pine sawdust should not exceed 10%. Further increases in the proportion of bakery waste did not yield relative benefits, due to the deterioration of the energy characteristics of the pellets obtained.

Steam explosion of lignocellulosic residues for co-production of value-added chemicals and high-quality pellets

The demand of pellets as energy carrier and the competitiveness of wood biomass are the drivers for finding alternative raw materials for production of pellets. The aim of this study was to investigate the steam explosion of lignocellulosic residues such as, straw, sawdust birch, sawdust spruce, GROT (mixture of 30 % bark and 70 % industrial chips), and their mix to co-production of value-added chemicals and high-quality pellets. The raw materials were first impregnated with water/acetic acid prior to steam explosion process, while leaching and washing of steam exploded biomass was used to reduce the ash content. The value-added chemicals were extracted with MIBK, and a gas chromatography was used to determine which value-added chemicals are present in the MIBK filtrates after extraction of the steam exploded biomass. Thermogravimetric analysis and Fourier transform infrared spectroscopy, elemental analysis, calorific values, compression strength and density were used to assess and compare the quality of steam exploded biomass and pellets quality. The results from the extraction experiments shows that furfural, HMF, vanillin, syringaldehyde and coniferaldehyde are the most value-added chemicals extracted from lignocellulosic residues where higher yield of the valuable chemicals was obtained when the biomass was presoaked in acetic acid. The ash content was reduced by 83 % for straw material by washing and leaching of steam exploded straw material when the biomass was presoaked in acetic acid. High quality pellets with high calorific value (20 MJ/kg), high compression strength (228 kN/m), high density (1300 kg/m3) and low ash content (0,06 %) were produced from sawdust spruce and GROT:Spruce mix used in our study. Based on our results, we can therefore suggest that steam explosion process of lignocellulosic residues improves the quality of the biomass to pellets production and at the same time open for the possibility to produce value-added chemicals.

Research on influence of grinding blast furnace return ore on reduction swelling index of low silicon fluxed pellets and production practice

Pellet quality is one of the key technologies restricting the smelting of high proportion pellets in the blast furnace, especially the reduction swelling index of low silicon fluxed pellets. In this paper, the inhibition effect of grinding blast furnace return ore on the reduction swelling index of low silicon fluxed pellets was studied and application has been conducted in Shougang Jingtang Company. The experimental results show that the addition of 5–15% fine grinding blast furnace ore into pellet production significantly reduced the reduction swelling index of pellets from 23.5% to 14.3%. Microstructure and energy spectrum analysis shows that calcium ferrite, magnesium ferrite and liquid phase in the pellets with fine grinding blast furnace return ore increased obviously with a more uniform distributed liquid phase between hematite particles than in the basic group pellets and tended to be “homogenized”. It is conducive to inhibiting the generation of ferric whiskers in the reduction process of the hematite phase, and thus contributes to the reduction of the swelling index. Since its implementation at Shougang Jingtang in 2020, this technology has yielded positive results. The fluxed pellets exhibit good quality with an alkalinity of 1.1, a SiO2 content of 2.1%, and a reduction in the swelling index from 18.1% to 16.5%. Besides, the pellet ratio into blast furnace has reached 55%, the cumulative average utilization coefficient of three 5500 m3 super-large blast furnaces is 2.43t/(m3. d), and the monthly average for a single furnace reaches 2.62t/(m3. d). Meanwhile, consumption reduction of calcium-containing flux slaked lime in fluxed pellets by 0.9% is greatly beneficial to reducing the cost of pellets and expanding the resources of pellet powder.

Evaluation of different Starch Binders on physical quality of fish feed pellets.

Binders are the products that are used to bind, glue or hold the various feed ingredients together in order to maintain pellet integrity. For aqua-culturists, feed manufacturing is an expensive exercise due to the high cost of ingredients along with traditional artificial binders. The use of grain starches as aqua feed binders have advantages which include availability of that binder, nutritional contribution, and minimization of feed cost. A research trial was conducted to test physical properties such as palatability, water stability, dustiness, friability, settling velocity and floatation time of locally available starch i.e. wheat gluten, pea starch and guar gum and to assist their incorporation in on-farm aqua feed. Results revealed that among these three starch, the starch from pea source was proved superior over other two (wheat gluten and guar gum) as all physical quality parameters (dustiness, water stability and friability) revealed better performance of pea starch except pelletability in which guar gum performed best. Although not a single diet proved best in case of flotation time (Tf) and settling velocity (Vset) at varying lengths (6mm, 9mm and 12 mm). This finding indicates the significance of suitable binders for optimal water pollution and sustainable aquaculture. The use of these binders i.e. wheat gluten, pea starch and guar gum in fish feed pellets may also reduce dependence on synthetic binders and minimizes cost.

تأثير حجم الدقائق وقطر ثقوب القالب في الآلة على نوعية الحبيبات العلفية لدجاج اللحم

Due to the need for controlling and regulating of feed pellet. Pellet that is imported or locally manufactured is accompanied by cracking and crumbling percentage that occur during transporting and distributing to animals, using conveyors and mechanical feeders. This study aimed to determine the effect of particle size and die holes diameter in the machine on broiler feed pellets quality in pellet durability, pellet direct measurement, pellet expansion, and pellet length. Three particle size 2, 4, and 6 mm, and three diameters of die holes in the machine 3, 4, and 5 mm, have been used. The results showed that changing the particle size from 2 to 4 then to 6 mm led to a significant decrease in pellet durability and pellet lengths, pellet expansion was increased, whereas it did not significantly effect on pellet direct measurement. Increasing the die holes diameter from 3 to 4 to 5 mm led to a significant decrease in pellet durability, pellet direct measurement and pellet lengths, increased pellet expansion. The particle size of the diet 2 mm and die holes diameter of 3 mm recorded the highest pellet durability at 93.40%, pellet direct measurement at 95.12%, pellet lengths at 86.96%, and less pellet expansion at 0.88%. The minimum particle size and die holes diameter gave the highest pellet durability, pellet direct measurement, pellet lengths, and lowest pellet expansion with all the considered indicators.

Pelletization of soil amendment: Optimizing the production and quality of soil amendment pellets from compost with water and biochar mixtures and their impact on soil properties

Pelletization of soil amendment: Optimizing the production and quality of soil amendment pellets from compost with water and biochar mixtures and their impact on soil properties

Insights into Properties of Biomass Energy Pellets Made from Mixtures of Woody and Non-Woody Biomass: A Meta-Analysis

There is a widespread global shift toward renewable energy sources, where the emphasis is on enhancing the utilization of renewable energy due to the rising costs associated with fossil fuels. In this light, biomass pellets made from woody and non-woody biomass and blends have gained increased attention. Extensive research has been conducted globally to enhance the quality of biomass pellets and to explore the potential to combine woody biomass with other non-woody forms of biomass in biomass pellet production. The heterogeneity of the raw materials used and resulting properties of the biomass pellets have led to the establishment of internationally recognized benchmarks such as the International Organization for Standardization (ISO) 17225 standard to regulate pellet quality. In this article, the key mechanical, physical, chemical, and energy properties of pellets made of different non-woody herbaceous biomass are investigated, and the available test values for such properties of the pellets were meta-analyzed. A comparison of the properties of these pellets with the relevant standards was also performed. A meta-analysis of studies on biomass pellet production was conducted via a comprehensive Systematic Literature Review (SLR). The SLR focuses on determining and analyzing the average values for the key physical properties of biomass pellets using woody biomass as a component in concert with other biomass materials. In addition, the optimal range of mixtures of woody and non-woody biomass was reviewed to produce biomass pellets with potential acceptance in the marketplace. The majority of studies included in the SLR concentrate on pellets made from a mixture of biomass materials. The results show that the average values for wood/non-wood mixtures such as pellet diameter, pellet length, moisture content, ash content, fine particle content, gross calorific value, and bulk density were found to adhere to the ISO standards. However, the average mechanical durability fell short of meeting the requirements of the standards. Additional comparisons were nitrogen, sulfur, volatile matter, and fixed carbon content. The findings in this meta-analysis could be useful in directing future research focused on producing high-quality and efficient biomass pellets derived from biomass blends and mixtures.