Distribution Of Pellets Research Articles

Logistic and Economical Preconditions for Production of Pellets From Sawdust

Abstract The objective of the paper was to determine the costs of production and production effectiveness of pellets made of sawdust and characteristics of logistics of raw material carriage and distribution of pellets. The scope of the paper covered the research carried out in the branch of DREWEX company located in Chotelek town (Świętokrzyskie voivodeship, Province of Busko Zdrój). Unit costs of pellets production were: 513.4 PLN∙t−1 for option 1, 423.3 PLN∙t−1 for option 2 and 393.3 PLN∙t−1 for option 3. The most favourable was option 3 when the pellets were produced on the technology line in the 3-shift system day and night. The average distance to seven cities from which sawdust was delivered was 43.6 km and the distance to which production was distributed to ten cities was on average 105.5 km.

An image-based method for online measurement of the size distribution of iron green pellets using dual morphological reconstruction and circle-scan

Particle size distribution (PSD) of green pellets is critically important in pelletizing process because it greatly affects the quality of iron ore oxidized pellet as well as the efficiency of blast furnace process. Image-based methods are effective in automatic measurement of PSD, but are limited in their capacity in segmenting overlapped pellets and computation efficiency. To overcome these shortcomings, a novel image segmentation algorithm is proposed in the present work, with which overlapped pellets in the image can be well separated and thus the PSD of iron green pellets can be measured online with good accuracy. The proposed algorithm first identifies the markers of each pellet directly from the greyscale image by a dual morphological reconstruction method, then a circle-scan method is proposed to split the overlapped pellets and measure the diameter of each segmented pellets. The proposed methods were verified by experiments and compared with methods available in literature as well as manual sieving results. It was demonstrated that the proposed algorithm achieves better segmentation performance and has an accuracy of 94.3%. The proposed measuring system has already been tested in a local steel company. Results show that the robustness and computing efficiency of the proposed image-based method is sufficient to satisfy the requirement for online PSD measurement in harsh environment of the pelletizing process.

Colonisation of plastic pellets (nurdles) by E. coli at public bathing beaches

The hard surface of waterborne plastic provides an ideal environment for the formation of biofilm by opportunistic microbial colonisers, and could facilitate a novel means of dispersal for microorganisms across coastal and marine environments. Biofilms that colonise the so-called ‘plastisphere’ could also be a reservoir for faecal indicator organisms (FIOs), such as Escherichia coli, or pathogenic bacteria such as species of Vibrio. Therefore, the aim of this study was to map the spatial distribution of beach-cast plastic resin pellets (nurdles) at five public bathing beaches, and quantify their colonisation by E. coli and Vibrio spp. Nurdles were heterogeneously distributed along the high tide mark at all five beaches, and each beach contained nurdles that were colonised by E. coli and Vibrio spp. Knowledge of E. coli colonisation and persistence on nurdles should now be used to inform coastal managers about the additional risks associated with plastic debris.

Energy Saving of Composite Agglomeration Process (CAP) by Optimized Distribution of Pelletized Feed

The composite agglomeration process (CAP) aims at sintering a pelletized feed and a matrix feed together to produce a high-quality burden for a blast furnace. The pelletized feed is balled from fine iron concentrate or refractory iron-bearing resources, while the matrix feed is granulated from iron ore fines, fuels, fluxes and so on. Through mathematical calculation, heat accumulation regularity and heat-homogenizing of the sinter bed are acquired in CAP when pelletized feed is uniformly distributed. Then they are studied in the composite agglomeration process with optimized pelletized feed distribution, which is a novel and perfect sinter bed structure. Results show that large heat input gaps exist in the sinter bed under condition of even sinter mixture distribution, and it is very difficult to realize bed heat-homogenization by directly varying the solid fuel dosage among each layer. An optimized pelletized feed distribution realizes more heat in the upper layer together with heat-homogenization of the middle-lower layer when the proportions of pellets increase first in the middle-upper layer and then decrease in the middle-lower layer of the sinter bed. Under these circumstances, the sinter bed has much better available accumulation ratios with a maximum value of 78.29%, and possesses a greater total heat input of 6754.27 MJ when the coke breeze remains at the original dosage. To make full use of the available heat accumulation and adjust the pellet distribution, a good energy saving effect is obtained because the coke breeze mass declines by 13.91 kg/t-sinter. The current gross heat inputs of each unit are reduced remarkably, leading to a total heat input decrease of 25.95%. In pot tests of CAP, the differences of thermal parameters in whole bed are obviously reduced with the optimized pelletized feed distribution, which contributes to sinter homogeneity and energy savings.

Plastic pellets, meso- and microplastics on the coastline of Northern Crete: Distribution and organic pollution

Plastic pollution in the marine environment is one of the foremost environmental problems of our time, as it affects wildlife and human health both directly and indirectly through the effects of contaminants carried by microplastics. This study investigates the temporal and spatial distribution of plastic pellets and fragments in sandy beaches along the coastline of Northern Crete, during 2013. Their densities varied throughout the year in each beach, with highest densities during the summer and towards the upper parts of the beaches. The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) sorbed on microplastics sampled from nine sandy beaches of Northern Crete was quantified using Gas chromatography – Ion Trap Mass Spectrometry (GC-ITMS). PAHs concentrations ranged from non-detectable levels to 1592 ng/g and fluctuated between sampling periods. Based on the observed patterns of meso- and microplastics distribution, practical guidelines are proposed to minimize the entrance of microplastics into the seawater wherefrom they are exceptionally difficult to collect, if mitigation actions are to be applied.

Consistent patterns of debris on South African beaches indicate that industrial pellets and other mesoplastic items mostly derive from local sources

Identifying the sources of small plastic fragments is challenging because the original source item seldom can be identified. South Africa provides a useful model system to understand the factors influencing the distribution of beach litter because it has an open coastline with four equally-spaced urban-industrial centres distant from other major source areas. We sampled mesodebris (∼2–25 mm) at 82 South African beaches in 1994, 2005 and 2015. Plastic items comprised 99% by number and 95% by mass of litter items. Industrial pellets were the most abundant plastic items, but fragments of rigid plastic items comprised most of the mass of debris. Strong correlations between industrial pellets and other plastic items indicate that common factors influence the distribution of both pellets and secondary mesoplastics. The abundance of mesodebris at beaches also was correlated in successive surveys, suggesting that beach-specific factors (e.g. aspect, slope, local currents, etc.) influence the amounts of debris on each beach. Sample year had no effect on mesodebris abundance, indicating that there has been little change in the amounts of mesodebris over the last two decades. There were consistently higher densities of both industrial pellets and other plastic items at beaches close to urban-industrial centres; there were only weak correlations with human population density and no correlation with local runoff. The size of industrial pellets decreased away from local urban centres, further supporting the conclusion that, like macroplastic litter, most mesoplastic pollution on continental beaches derives from local, land-based sources. This finding means that local actions to reduce plastics entering the sea will have local benefits, and that it may be possible to assess the efficacy of mitigation measures to reduce marine inputs of mesoplastic items.

Investigating the future supply distribution of industrial grade wood pellets in the global bioenergy market

ABSTRACTMany factors may globally affect the trade pattern for industrial-grade wood pellets, with one such factor being the decision strategies by potential buyers and suppliers to optimize feedstock price and volume. This study investigated the industrial-grade wood pellet market assuming potential buyers and suppliers optimize their decision independently. A non-cooperative, bi-level, Stackelberg, leader-follower game model was developed to predict potential resource distribution in global competitive feedstock markets for industrial-grade wood pellets. Based on historic trade patterns and expected future production and demand structures, a set of potential buyers and suppliers of industrial-grade wood pellets were identified for 2022, 2030, and 2040. Projected trade volume and patterns among buyers and suppliers were identified in different scenarios. Potential buyers for US-sourced industrial grade-wood pellet were identified. Results shows that the expected demand growth from the European Union, South Korea, and Japan until the year 2030 limits the resources available to the USA. Competitive prices offered by international buyers cause the US industry to primarily sell overseas. International trade could contribute to 83.4% of the total volume in 2022 and 90.2% of the total trade value in 2022. High-demand markets with a respective high willingness-to-pay dominate international trade.

A non-destructive method for quality control of the pellet distribution within a MUPS tablet by terahertz pulsed imaging

Terahertz pulsed imaging (TPI) was applied to analyse the inner structure of multiple unit pellet system (MUPS) tablets. MUPS tablets containing different amounts of theophylline pellets coated with Eudragit® NE 30 D and with microcrystalline cellulose (MCC) as cushioning agent were analysed. The tablets were imaged by TPI and the results were compared to X-ray microtomography. The terahertz pulse beam propagates through the tablets and is back-reflected at the interface between the MCC matrix and the coated pellets within the tablet causing a peak in the terahertz waveform. Cross-section images of the tablets were extracted at different depths and parallel to the tablet faces from 3D terahertz data to visualise the surface-near structure of the MUPS tablets. The images of the surface-near structure of the MUPS tablets were compared to X-ray microtomography images at the same depths. The surface-near structure could be clearly resolved by TPI at depths between 24 and 152μm below the tablet surface. An increasing amount of pellets within the MUPS tablets appears to slightly decrease the detectability of the pellets within the tablets by TPI. TPI was shown to be a non-destructive method for the detection of pellets within the tablets and could resolve structures thicker than 30μm. In conclusion, a proof-of-concept was provided for TPI as a method of quality control for MUPS tablets.

Oblique-incidence reflectivity difference application for morphology detection.

Analogous with scanning electron microscopy, we use an oblique-incidence reflectivity difference (OIRD) approach for morphology detection. By scanning the active carbon clusters in a one-dimensional way and the reservoir rocks in a two-dimensional way, the morphology of the samples' surface can be revealed in OIRD signal images. High OIRD signals of active carbon samples refer to the centralized distribution areas of carbon, and the fluctuations are caused by the uneven distribution of carbon pellets. OIRD intensity is proportional to the thickness of materials. In terms of rocks, the trough areas with smaller values refer to the low-lying fields. The areas with relatively large OIRD intensities correspond to the protuberance areas of rocks. Consequently, OIRD is a sensitive yet rapid measure of surface detection in material and petrogeology science.

Automatic Image Processing based Size Characterization of Green Pellets

The size of pellets has a significant effect on the performance of blast furnaces. Based on experience, the universally accepted size of pellets for efficient blast furnace operations is between 9 millimeters to 16 millimeters. But presence of smaller size pellets or fines lowers the blast furnace stack permeability, increases dust losses and may lower the maximum permissible blast temperature for smooth operation of the furnace. Pellets too big are also undesirable, particularly if its reducibility is low and is poor in strength, thus undergoing physical degradation during furnace operation.This paper relates to a non-contact method of measuring the size of green pellets being fed into the Blast furnace. A method is developed for the automatic size characterization of green pellets in the conveyor belts before the pellets are being indurated in a travelling grate furnace to confer the required physical and metallurgical properties. The method employs imaging and illumination devices installed in the conveyor belt in the pellet plant of Tata Steel and then, processing those images using imaging algorithms to obtain the size distribution. Apart from the size distribution of the green pellets, the system also identifies the pelletizing disc from which the green balls originated so as to effectively control the pelletizing process.

Plastic Pellets on Campeche Beach (Santa Catarina Island, Brazil): A Seasonality and Composition Study

Alerts regarding marine contamination by microplastics motivated this study, conducted in Santa Catarina Island, South Brazil. During 12 sampling events, spatial and temporal distribution of plastic resin pellets, collected at two locations of Campeche beach, was analyzed, and polymer composition was identified. Plastic pellets were found in every sampling day, with a mean average of 1.16 pellets/ m2. Their abundance was influenced by two factors: Sampling location and Sampling day nested in each Season. There was a variable abundance along the monitoring period, with an increase of pellets in autumn. A significantly higher amount of pellets was found in one sampling place. The composition of the sampled pellets was heterogeneous, with a prevalence of low density polyethylene polymers. It is clear that a series of proceedings regarding production, stocking, transport and transformation of plastic pellets, must be considered, to avoid pellets loss of into the environment.

Quantifying microplastic pollution on sandy beaches: the conundrum of large sample variability and spatial heterogeneity.

Despite the environmental risks posed by microplastic pollution, there are presently few standardized protocols for monitoring these materials within marine and coastal habitats. We provide a robust comparison of methods for sampling microplastics on sandy beaches using pellets as a model and attempt to define a framework for reliable standing stock estimation. We performed multiple comparisons to determine: (1) the optimal size of sampling equipment, (2) the depth to which samples should be obtained, (3) the optimal sample resolution for cross-shore transects, and (4) the number of transects required to yield reproducible along-shore estimates across the entire sections of a beach. Results affirmed that the use of a manual auger with a 20-cm diameter yielded the best compromise between reproducibility (i.e., standard deviation) and sampling/processing time. Secondly, we suggest that sediments should be profiled to a depth of at least 1m to fully assess the depth distribution of pellets. Thirdly, although sample resolution did not have major consequence for overall density estimates, using 7-m intervals provides an optimal balance between precision (SD) and effort (total sampling time). Finally, and perhaps most importantly, comparing the minimum detectable difference yielded by different numbers of transects along a given section of beach suggests that estimating absolute particle density is probably unviable for most systems and that monitoring might be better accomplished through hierarchical or time series sampling efforts. Overall, while our study provides practical information that can improve sampling efforts, the heterogeneous nature of microplastic pollution poses a major conundrum to reproducible monitoring and management of this significant and growing problem.

Investigating Abundance, Distribution and Accumulation of Plastic Resin Pellets and Fragments in the Caspian Sea: A Case Study of Noor Shores

Investigating Abundance, Distribution and Accumulation of Plastic Resin Pellets and Fragments in the Caspian Sea: A Case Study of Noor Shores

Regulation of Diet in the Fire Ant, Solenopsis invicta

In social insects, colony nutrition depends upon the volume and quality of food distributed, ingested, and assimilated by its members. The ability of Solenopsis invicta workers and larvae to regulate the volume of food ingested individually has been well documented. In this paper, the ability of fire ant workers and larvae to regulate the quality and type of food ingested is demonstrated. Larvae displayed independent appetites for solid protein, amino acid solution, and sucrose solution. When larvae that had fed on one food type were switched to another, they fed on the second food type at rates characteristic of that food type, not of the volume of food previously ingested. Larvae preferred concentrated sucrose and amino acids solutions over dilute solutions. Larval “fullness” was thus a relative property, depending upon the nature of food as well as the volume ingested. The number of workers recruiting to food sites also depended upon food concentration and food type. Workers preferred sucrose to amino acids, concentrated to dilute solutions, and novel to accustomed food. The absence of protein in the worker diet rather than the presence of larvae caused workers to switch their preference from sugar to amino acids solutions. When the colony was offered sucrose and amino acids solutions simultaneously, individual workers ingested from one or the other site, but not both. Little mixing of crop contents occurred when workers solicited from one another inside the nest. Workers tended to regurgitate to larvae after ingesting amino acids and to other workers after ingesting sucrose. The mechanism regulating the distribution of protein pellets, which workers do not ingest, among larvae is unknown. In summary, colony nutrition was regulated by a chain of demand. Forager hunger determined the rate at which food flowed from the environment into the nest. Larval hunger and nest-worker hunger determined the rate and direction in which food moved within the nest.

Designing a maritime supply chain for distribution of wood pellets: a case study from southern Norway

Heat is traditionally produced from non-renewable energy sources. Some of this energy could be produced from renewable energy sources such as wood pellets. In Norway, pellets are today transported by trucks, but it is not profitable to use the road-based transportation network for long distances. Therefore, the Norwegian consumption of pellets is low. The purpose of this paper is to present a feasibility study for evaluating if a maritime supply chain for distribution of pellets along the Norwegian coast is economically viable. A mixed integer programming model is developed as a basis for decision support, and the model utilizes the structure of the geographical network resulting in a novel and innovative formulation of the problem. The main findings are that the operating profit margin is around 8% for the supply chain and that the model is flexible and able to design maritime distribution chains that are suitable for different levels of demand.

In-depth characterisation of a mixture composed of powder/pellets MX80 bentonite

Mixtures made up of bentonite powder and pellets are a possible candidate for making sealing plugs used in deep radioactive waste disposal due to their low permeability, high swelling capacity, favourable properties with respect to radionuclide retention and operational advantages in terms of placement in situ, which is much easier than that of pre-compacted bricks of bentonite/sand mixture. It is therefore essential to better understand their hydro-mechanical behaviour to optimize the design of the repository. In this context, the French Institute for Radiation Protection and Nuclear Safety (IRSN) has launched the SEALEX project (SEALing performance EXperiments) in which this work has been conducted.Once the initially heterogeneous unsaturated powder/pellet (80/20) MX80 bentonite mixture is put in place, these sealing materials will be subject to coupled hydro-mechanical loadings: hydration due to the infiltration of pore water from the natural barrier and mechanical confinement resulting from the engineered barriers. The present work focuses on the different scales of the material: at the macroscopic scale, it is characterised by a heterogeneous distribution of pellets and powder of bentonite; at the microscopic scale, it is studied by several techniques (MIP, μ-CT observations and SEM). From MIP results, a typical bimodal distribution was found for both pellet and powder. From μ-CT and SEM observations, a heterogeneity was revealed in the internal structure of the pellet: heterogeneous density distribution of the clay minerals and presence of several high density elements.

Multispectral UV imaging for surface analysis of MUPS tablets with special focus on the pellet distribution

In the present study the applicability of multispectral UV imaging in combination with multivariate image analysis for surface evaluation of MUPS tablets was investigated with respect to the differentiation of the API pellets from the excipients matrix, estimation of the drug content as well as pellet distribution, and influence of the coating material and tablet thickness on the predictive model. Different formulations consisting of coated drug pellets with two coating polymers (Aquacoat® ECD and Eudragit® NE 30 D) at three coating levels each were compressed to MUPS tablets with various amounts of coated pellets and different tablet thicknesses. The coated drug pellets were clearly distinguishable from the excipients matrix using a partial least squares approach regardless of the coating layer thickness and coating material used. Furthermore, the number of the detected drug pellets on the tablet surface allowed an estimation of the true drug content in the respective MUPS tablet. In addition, the pellet distribution in the MUPS formulations could be estimated by UV image analysis of the tablet surface. In conclusion, this study revealed that UV imaging in combination with multivariate image analysis is a promising approach for the automatic quality control of MUPS tablets during the manufacturing process.

Feed spreaders in sea cage aquaculture – Motion characterization and measurement of spatial pellet distribution using an unmanned aerial vehicle

Pneumatic rotary feed spreaders represent essential equipment in the feeding system of present day industrial-scale sea cage aquaculture. This study presents experimentally obtained attitude measurements and corresponding surface distribution patterns of pellets in order to characterize the dynamic behavior and performance of such spreaders. Spreader attitude and direction were measured by employing an attitude and heading reference system along with a rotary encoder. In addition, an unmanned aerial vehicle (UAV) was used to record pellet surface impacts from the air, and the position and direction of the spreader was obtained by applying computer vision methods to the recorded video. The proposed UAV method was fast to deploy, requires minimal equipment installation and presents a viable alternative to the approach of collecting pellets manually using Styrofoam boxes as reported in earlier studies. The findings from this study may be used as a base for further development and refinement with respect to using an UAV to observe the performance and spatial pellet distribution from various feed spreaders used in aquaculture. Such a tool may be valuable for farmers and equipment producers which may easily evaluate the performance of various spreader designs. In addition, the results serve as valuable input for parametrization and validation of mathematical feed spreader models.

An industrial image processing-based approach for estimation of iron ore green pellet size distribution

Green pellets are spherical objects mainly made from crushed iron and water in rotating pelletizing disk. Pellets play an important role in the process of direct reduction steel manufacturing. For high quality steel production, pellets should be of an appropriate size. Oversized pellets cannot be properly cooked in furnace and undersized pellets may pass through metal grid of the furnace, which affects the performance of the process. In most of the steel manufacturing companies, operators use sequential sampling and traditional methods to measure size of pellets, however, limited number of tested pellets, low speed of the quality control and human errors are the most common drawbacks of this method. A solution to these shortcomings is continuous monitoring and accurate measurement through a fully-automatic approach. In this paper, a method using image processing technique is proposed and verified for estimating size distribution of iron-ore green pellets. For segmentation of single and multiple pellets in images captured from live video, we have utilized morphological methods, watershed algorithm, and linear searching. Then, a Support Vector Machine (SVM) is employed for classification of segmented pellets. The proposed method has already been implemented in Mobarakeh Steel Complex, where the method was tested on about 1000 sample pellets. Results show that the accuracy of method is 95.1% in detection of single pellet elements.

Modelling growth performance and feeding behaviour of Atlantic salmon (Salmo salar L.) in commercial-size aquaculture net pens: Model details and validation through full-scale experiments

We have developed a mathematical model which estimates the growth performance of Atlantic salmon in aquaculture production units. The model consists of sub-models estimating the behaviour and energetics of the fish, the distribution of feed pellets, and the abiotic conditions in the water column. A field experiment where three full-scale cages stocked with 120,000 salmon each (initial mean weight 72.1±SD 2.8g) were monitored over six months was used to validate the model. The model was set up to simulate fish growth for all the three cages using the feeding regimes and observed environmental data as input, and simulation results were compared with the experimental data. Experimental fish achieved end weights of 878, 849 and 739g in the three cages respectively. However, the fish contracted Pancreas Disease (PD) midway through the experiment, a factor which is expected to impair growth and increase mortality rate. The model was found able to predict growth rates for the initial period when the fish appeared to be healthy. Since the effects of PD on fish performance are not modelled, growth rates were overestimated during the most severe disease period.This work illustrates how models can be powerful tools for predicting the performance of salmon in commercial production, and also imply their potential for predicting differences between commercial scale and smaller experimental scales. Furthermore, such models could be tools for early detection of disease outbreaks, as seen in the deviations between model and observations caused by the PD outbreak. A model could potentially also give indications on how the growth performance of the fish will suffer during such outbreaks. Statement of relevanceWe believe that our manuscript is relevant for the aquaculture industry as it examines the growth performance of salmon in a fish farm in detail at a scale, both in terms of number of fish and in terms of duration, that is higher than usual for such studies. In addition, the fish contracted a disease (PD) midway through the experiment, thus resulting in a detailed dataset containing information on how PD affects salmon growth, which can serve as a foundation to understanding disease effects better.Furthermore, the manuscript describes an integrated mathematical model that is able to predict fish behaviour, growth and energetics of salmon in response to commercial production conditions, including a dynamic model of the distribution of feed pellets in the production volume. To our knowledge, there exist no models aspiring to estimate such a broad spectre of the dynamics in commercial aquaculture production cages. We believe this model could serve as a future tool to predict the dynamics in commercial aquaculture net pens, and that it could represent a building block that can be utilised in a future development of knowledge-driven decision-support tools for the salmon industry.