Transport Of Bulk Materials Research Articles

Investigation of the effects of radial clearance on the screw conveyor performances for different inclinations

Screw conveyors are widely used for bulk material transportation. This study investigates the critical role of radial clearance, the gap between the screw and the conveyor body, on performance across various inclination angles. The Discrete Element Method (DEM) is employed to analyze the effects of different radial clearances on conveyor performance for concrete aggregate and sand as bulk materials. Volumetric efficiencies and capacity losses serve as key performance indicators, quantitatively assessed for each radial clearance and inclination combination. Experimental validation is conducted to corroborate the findings. In the study, the optimal radial clearance was identified as 1.5 to 3 times of the particle size. This optimal clearance minimizes the material jamming and increases the performance for screw conveyors with different inclinations and bulk material types as a result.

Semantic segmentation of thermal defects in belt conveyor idlers using thermal image augmentation and U-Net-based convolutional neural networks

The belt conveyor (BC) is the main means of horizontal transportation of bulk materials at mining sites. The sudden fault in BC modules may cause unexpected stops in production lines. With the increasing number of applications of inspection mobile robots in condition monitoring (CM) of industrial infrastructure in hazardous environments, in this article we introduce an image processing pipeline for automatic segmentation of thermal defects in thermal images captured from BC idlers using a mobile robot. This study follows the fact that CM of idler temperature is an important task for preventing sudden breakdowns in BC system networks. We compared the performance of three different types of U-Net-based convolutional neural network architectures for the identification of thermal anomalies using a small number of hand-labeled thermal images. Experiments on the test data set showed that the attention residual U-Net with binary cross entropy as the loss function handled the semantic segmentation problem better than our previous research and other studied U-Net variations.

Belt conveyor speed detection based on fiber-optic Sagnac interferometer vibration sensor

With their long transportation distance and high productivity, belt conveyors are characterized as the main equipment for bulk material transportation in coal mines and other key industries. However, its speed detection method has always been an engineering challenge under harsh working conditions. In this work, the elastic-optical effect of the polarization-maintaining fiber is used to design a fiber ring laser vibration sensing system based on a fiber-optic Sagnac interferometer vibration sensor and its packaging structure. The vibration detection is achieved by detecting the change in optical power at the working wavelength, and the belt conveyor speed measurement is completed by detecting the vibration frequency. With such a method, the belt conveyor speed measurement obtained a relative error of less than 1.88%. The proposed method bears the characteristics of anti-electromagnetic interference, intrinsic explosion-proof, and adapts to the harsh smoke and dust working environment, which has a wide range of application prospects in the fields of engineering, machinery, security, etc.

Impact of the COVID-19 lockdown to a port-city area: A two-year comparative PMF analysis of PM10 of polluting sources

The objective of this study was to evaluate the effects that the COVID-19 lockdown had in the PM10 levels and sources in a city adjacent port where the transport of bulk materials is one of the main activities. For this, the 2020 PM10 chemistry and sources will be compared to an annual baseline period of 2017-18 in the same area.A total of 337 samples were chemically analyzed (30 chemical species) and a positive matrix factorization model was used to identify major PM10 sources. A Mann-Whitney test was used to find statistically relevant differences between periods.The model identified 8 factors two of them directly related to port activities (Shipping emissions and bulk materials), one associated to road traffic, three linked secondary sources (aged sea salt, secondary nitrate, ammonium sulfate) and two natural sources including fresh sea salt and long-range transport from Saharan intrusions.Road traffic and Shipping sources show a significant reduction in the lockdown period. However, after this period, the road traffic source quickly recovered showing no differences on a yearly basis with the reference year. Only the Shipping emissions source were greatly reduced in 2020 compared to 2017-18. On the other hand, the influence of natural sources kept PM10 from reducing drastically during the lockdown year (2020).

Application of EDEM Simulation for Calculating and Optimizing a Closed Coal Fly Ash Screw Conveyor

In contemporary bulk material transportation systems, closed screw conveyors have become prevalent. These conveyors, enclosed within troughs or cylindrical bodies, effectively mitigate environmental contamination and material toxicity during transit. Their hermetic design prevents material dispersion by wind, thereby minimizing losses and preserving the integrity of raw materials, particularly those with potential health implications such as urea and cement. Consequently, employing a screw conveyor constitutes a prudent safety measure. Despite the widespread use of screw conveyors, a comprehensive understanding of the behavior of material particles within these systems remains elusive and subject to discrepancies across various methodologies. Presently, a multitude of calculation methods and applications exist, resulting in disparities between theoretical computations and practical implementation. Drawing upon Alan W. Roberts’ meticulously devised calculation methodology, renowned for its precision, the authors have developed a swift computational tool utilizing VBA Excel software 2023. Additionally, EDEM simulation software was employed to model granular material behavior. The ensuing calculations guided the selection of optimized technical dimensions for the screw conveyor, which were then fabricated and subjected to real-world testing at the Vinh Tan thermal power plant. Remarkably, the achieved output capacity demonstrated a mere 7% deviation from calculations performed with the VBA program and a 2% variation from those conducted via EDEM simulation. Furthermore, a comprehensive graph depicting the relationship between screw conveyor speed and capacity has been provided, affording a means to finely tune throughput with exceptional accuracy along the production line. The results obtained provide the basis for the development of a device that meets the required capacity specifications accurately and precisely on the first attempt. This accomplishment satisfies stringent capacity standards without the need for any adjustments or modifications, all while ensuring minimal cost and time efficiency.

Deep-learning-based multistate monitoring method of belt conveyor turning section

During transportation, bulk materials are susceptible to spillage due to equipment instability and environmental factors, resulting in increased maintenance costs and environmental pollution. Thus, intelligent and efficient condition monitoring is crucial for maintaining operational efficiency of transfer equipment. It facilitates the timely identification of potential safety hazards, preventing accidents from occurring or their impact from spreading, thereby minimizing production and maintenance costs. This study presents a deep-learning-based multioperation synchronous monitoring method suitable for belt conveyors that integrate target segmentation and detection networks to simultaneously diagnose belt deviation, measure conveying load, identify idlers, and do other tasks on a self-made dataset. This method effectively reduces the complexity of multistate simultaneous monitoring and monitoring costs, thereby avoiding environmental pollution caused by transportation accidents. Experimental results show that the segmentation accuracy of the proposed method can be up to 88.72%, with a detection accuracy of 91.3% and an overall inference speed of 90.9 frames per second. Furthermore, by extending the dataset, the proposed method can incorporate additional tasks, such as belt damage, scattered material, and foreign object identifications. This study has practical significance in ensuring the normal and eco-friendly operation of bulk material transportation. Our source dataset is available at https://github.com/zhangzhangzhang1618/dataset-for-turnning-section

Enhanced Real-Time Maintenance Management Model—A Step toward Industry 4.0 through Lean: Conveyor Belt Operation Case Study

Conveyor belts (CBs) are widely used for the continuous transport of bulk materials. CBs must be extremely reliable due to the cost associated with their failure in continuous production systems. Thus, it is highly relevant in terms of maintenance and planning to find solutions to reduce the existing stoppages from these assets. In this sense, it is essential to monitor and collect real-time data from this piece of equipment. This work presents a case study, where a model that combines the Lean Philosophy, Total Productive Maintenance (TPM), and the enabling technologies of Industry 4.0 is applied to a CB. The proposed model monitors the CB and provides data on its operation, which, using the calculation of indicators, allows a more accurate and thorough view and evaluation, contributing to improving and supporting decision making by those responsible for maintenance. The data collected by the sensor help those responsible for maintenance and production, in the readjustment of more accurate and optimized planning, programming, and execution, supporting decision making in these areas. During the field test of a two-hour monitoring period (10 a.m. to 12 p.m.), the model identified six stoppages, resulting in approximately 88.6% of operational time for the conveyor. The field test showed that this model can result in more accurate maintenance decision making than conventional approaches. This research also contributes to the advancement of electronics and industrial automation sectors by empowering companies to transform maintenance methodologies. The potential of this approach and its implications for enhanced productivity and overall performance are therefore highlighted.

The correlation between the pre-consolidation and Instantaneous Yield Locus (IYL) of bulk solids

The storage and transportation of bulk materials has seen a continuous increase in demand with the evolution of renewable energy systems and modern society. The extraction of minerals such as iron ore, copper, nickel, bauxite, and lithium is leading to the exploitation of previously abandoned mine sites as well as ore bodies that may have been disregarded. This demand necessitates more efficient systems to transport these bulk commodities from the mine site to the export terminal or end user. The design of new bulk material handling systems typically requires the measurement of the bulk material strength, commonly determined using a Jenike direct shear tester. Initially, these measurements were used for the design of free-flowing bulk commodities, such as grain in storage silos or granaries. Over more recent decades, Jenike direct shear measurements have been used for the determination of the flow properties of problematic bulk materials which show cohesive characteristics. Specifically, this testing is used to define the flow function of a bulk material, the relationship between the material strength and major principle stress, which is subsequently used in the design of material handling systems.This paper provides a mathematical relationship between the pre-consolidation and the Instantaneous Yield Locus (IYL) of a bulk material sample under Jenike direct shear testing conditions. When the voidage between the particles is considered, this relationship becomes critical in defining the stress states of a bulk material sample. By understanding these stress conditions, further insight into the tensile forces which lead to problematic material behaviours can also be gained. This becomes increasingly important when low consolidation applications, such as transfer chutes, are considered as this leads to blockages and therefore downtime and lost revenue within a mining operation results. To further gain an understanding of the tensile forces acting within a bulk material sample, inter-particle adhesion tests are compared with predicted values which are determined using the outlined mathematical relationship.

Review of UK Inland Waterways Transportation From the Hydrodynamics Point of View

There are approximately 7,000 miles of inland waterways in the UK, many of them built during the 18th and 19th centuries principally to transport bulk materials. These waterways provide numerous benefits to society and the economy. However, they have untapped potential for freight transport which could be released to provide more efficient solutions compared to other modes of transport. In addition to providing solutions to reduce emissions from land or air transportation, inland waterways also bring environmental and public health benefits to local communities. Therefore, these blue-green spaces should play a central role in government and local authority planning. This article explores some of the issues which prevent full use of inland waterways transportation from being achieved from the hydrodynamics point of view. Specifically, the concepts and ideas underpinning vessel operation are reviewed and discussed in detail in this article. It is shown how hydrodynamic concepts can inform public policy to maximise the efficiency of transportation from inland waterways.

Investigation of Bulk Material Transportation by Screw Conveyer with Hinge-Pan Operating Device

The article presents a new design of a hinged and sectional working body and substantiates its optimal parameters for ensuring the movement of loose materials along curvilinear routes. Analytical dependencies have been derived to determine the rational design and power parameters of the hinged-sectional working body, and the functional dependencies of the minimum permissible radius of curvature of the RC technological highway on the angular rotation of adjacent sections and their design parameters have been established. The axial speed and power of cargo transportation by the articulated-sectional working body of the screw conveyor along a curved route have been determined. Experimental studies have been conducted to determine the influence of the number of revolutions, the height of material lifting and the radius of curvature of the flexible helical sectional working body RC on the torque T, as well as the determination of the influence of the number of revolutions n, the filling factor of the main line ψ and the diameter of the main line D on the performance Q when transporting loose materials.

Multi-objective Optimal Scheduling of Stacker–reclaimers Using the RPCNSGA II Algorithm

Background: The stacker-reclaimer is a device for transporting bulk materials in ironmaking raw material yards. An excellent scheduling plan can provide a good raw material supply basis for steel enterprises. It is of great significance to improve the efficiency of steel production, reduce unnecessary operating waste and management costs, and realize scientific management of steel production. Objective: This patent aims to optimize the total material transportation time and equipment utilization balance within a single operation plan of the stacker-reclaimer involved in the raw material yard. Methods: A multi-objective optimization model for the stacker reclaimer is established, and the Reverse learning and Population Competitive-NSGA II (RPC-NSGA II) algorithm is introduced for solving. This algorithm uses reverse learning and population competition mechanism to improve the convergence and diversity of the algorithm. Results: The proposed method was experimentally verified in a raw material yard with a 360m2 sintering machine and a bulk material port. The method converges well and obtains a Pareto front with a uniform distribution. Compared with the actual scheduling plan, the scheduling plan under the optimal compromise solution reduces the maximum completion time by 11.23 minutes and increases the equipment utilization balance rate by 11.70%. Conclusion: The proposed method can consider the material transportation time and equipment utilization balance, which is of great significance for the optimized use of the stacker reclaimer in steel enterprises and the quality assurance of raw material supply

CFD-DEM coupled calculation of wall wear characteristics during particles flow impacting the wall process

The continuous impact of the particles flow on the wall during industrial bulk material transport can lead to wall wear. In this paper, a physical model of the particle flow impacting the wall at different angles is established, and the wear condition of the particles flow impacting on the wall is studied by using the coupling method of CFD-DEM. Firstly, the accuracy of the erosion model is verified by the existing experimental data. Secondly, the effects of particle incidence angle, particle velocity and particle volume fraction on wall wear are analyzed by numerical calculation. The results show that the mass loss and erosion ratio of the target plate are the largest when the particle incidence angle is between 15° and 30°. When the particle incidence angle is near 45°, the maximum wear depth will appear on the wall surface. The increase of particle impact velocity led to an exponential increase in the mass loss, erosion ratio and wear depth of the target plate, but did not change the wall wear morphology. The particle volume fraction is positively correlated with the mass loss of the target plate. With the increase of particle volume fraction, the change of erosion ratio is more obvious at 90° impact, but has little effect at 45° impact. The change of particle volume fraction has an important effect on the wall wear morphology.

Vibration and Noise Analysis and Experimental Study of Rail Conveyor

The rail conveyor is a new type of energy-saving system for the long-distance transportation of bulk materials. Operating noise is an urgent problem that the current model faces. It will cause noise pollution and affect the health of workers. In this paper, the factors causing vibration and noise are analyzed by modeling the wheel-rail system and the supporting truss structure. Based on the built test platform, the system vibration of the vertical steering wheel, the track support truss, and the track connection were measured, and the vibration characteristics at different positions were analyzed. Based on the established noise and vibration model, the distribution and occurrence rules of system noise under different operating speeds and fastener stiffness conditions were obtained. The experimental results show that the vibration amplitude of the frame near the head of the conveyor is the largest. The amplitude under the condition of 2 m/s running speed at the same position is 4 times that under the condition of 1 m/s. At different welds of the track, the width and depth of the rail gap have a great influence on the vibration impact, which is mainly due to the impact of the uneven impedance at the track gap, and the greater the running speed, the more obvious the vibration impact. The simulation results show the trend of noise generation, the speed of the trolley, and the stiffness of the track fasteners have a positive effect on the generation of noise in the low-frequency region. The research results of this paper will play an important role in the noise and vibration analysis of rail conveyors and help to optimize the structure design of the track transmission system.

Experimental Study of Rubber Composite Quality Assessment in Terms of Electrical Conductivity and Accelerated Thermal Ageing

Belt conveyors represent efficient transport systems that are used for transportation of bulk materials across all industries. Their basic structural component is a conveyor belt. During storage and deployment, conveyor belts undergo an inevitable process of ageing which leads to deterioration of their properties. A challenge associated with the use of conveyor belts is to ensure the required electrical conductivity. This challenge has prompted the research into conveyor belts that was aimed at identifying their electrical conductivity, considering primarily the effects of ageing. Identification of electrical conductivity of newly manufactured conveyor belts is important for manufacturers in order to comply with relevant standards, and for conveyor belt users in order to eliminate potential hazards.

The detection of forces acting on conveyor rollers of a laboratory device simulating the vertical section of a Sandwich Belt Conveyor

Using certain belt conveyors of a special design, it is possible to transport bulk material at angles of transport inclination significantly exceeding the permissible angle of inclination for traditional design. A special design of such a belt conveyor, described in this paper, uses the so-called cover belt to transport bulk materials at inclination angles from 20 to 90 degrees. By applying its weight or employing pressure, it exerts pressure on the surface of the layer of the transported material that is spread on the surface of the carrying belt. This paper aims to describe the laboratory measurement methodology and to detect the magnitude of the horizontal compressive forces of the transported bulk material acting on conveyor rollers (idlers). The article lists in the tables horizontal compressive forces obtained by measuring, which help to deduce the height of a bulk material column and its cross-section S2 [m2], defined by the width b [m] and height h [m] of the belts interspace. Knowledge of the magnitude of horizontal forces acting on conveyor rollers allows us to suitably design the stiffness of the compression coil spring in the pressing mechanism. It eliminates the undesirable shifts of working surfaces from the conveyor belts (carrying and covering), which prevents the flow of the transported material grains over the edges of the conveyor belts. One of the possible designs for the pressure mechanism is presented in this article. The article shows the values of the difference between the ratio of the measured compressive forces against the value of theoretically calculated stresses for different heights of the bulk material column and different heights of the interspace. For the maize material, the largest difference in the ratio of the measured compressive forces to the value of the theoretically calculated stresses was 78.1% and for river gravel, it was 71.6%.

USING HYDRAULIC PARAMETRIC VIBRATION EXCITER IN AGRICULTURAL ENGINEERING

Vibration technology is widely used in mechanical engineering, construction, road building and different sectors of the manufacturing. In agriculture, it is used for dosing feed, cleaning and sorting seeds, digging up root crops, planting potatoes, and transporting bulk materials. Vibrations make the mechanical system more stable in relation to external force disturbances and do not change the technological properties of materials during its movement along the working surfaces. Also, the material passing through the vibration zone is not damaged. A wide range of frequency and amplitude of vibrations provides the possibility of vibration regime varying, and the characteristics of the movement of agricultural plant material on the vibrating working bodies. The analysis of possibility of application of vibrating hydraulic drives as elements of transmission of movement to working bodies of agricultural machines is executed. A historical excursion was conducted and the first mentions of the use of hydraulic drives were pointed out. The estimation of technological processes in agricultural production where it is expedient and possible to use vibration and vibrating drives is made. At the present stage of development of agricultural engineering, using vibrating hydraulic drive is accorded to the basic trends of agriculture machinery development. The stand for conduction of studies of amplitude-frequency characteristics of the vibrating drive with regulated perturbations is offered. A mathematical model is presented, which generally describes the course of the vibration process and estimates the stiffness of the mechanical system. The hydraulic parametric vibration exciter is recommended to use for studying and determination the conditions for the occurrence of parametric vibrations in working body of agricultural machines. Also, using a hydraulic drive makes it possible to simplify the kinematics, reduce metal consumption, increase accuracy, reliability and level of automation of working bodies of agricultural machines.

Experimental determination of force acting on a sandwich conveyor’s pressure roller in transport of bulk materials for the needs of failure analysis

Sandwich conveyors are among continuous transport systems used to transport bulk materials over short distances. The principle of their operation deploys the one of classic belt conveyors. However, in contrast to them, they use two parallel conveyor belts, between which the bulk material is transported. The conveyor belts are pressed against transported material by pressure rollers. As a result of mutual interaction, forces emerge which make transport of bulk material possible at angles that conventional belt conveyors cannot handle. The magnitude and effect of these forces are most pronounced at the points of conveyor belt’s contact with pressure rollers. However, in case of insufficient pressure, the transport process fails, and the conveyor is unable to perform its function. Through experimental measurements, it was found that the pressing force magnitude is about 20.8% smaller compared to the opposite arrangement and a roller spacing of 330 mm, and by 13.4% with a roller spacing of 660 mm. The aim of the paper is to design a measurement system and identify the magnitude of forces, using experimental measurements, based on which regression models can be determined and used in failure analysis. The paper presents results that can be applied in online monitoring of this type of transport for the needs of failure analysis, prediction, and operational indicator’s assessment. Thus, preconditions are created to include such a type of transport system among the ones meeting Industry 4.0 criteria in the field of failure analysis.

Investigation of The Dynamic Deflection of Conveyor Belts Via Simulation Modelling Methods on Idler Factor

Belt conveyor is today’s very important mechanism in material handling industries and is most commonly used to transport bulk materials such as grain, salt, coal and sand. Belt deflection indicates belt is loosening. It occurs between the idler roll sets due to the self-weight of the belt and the forces from the bulk material. This paper includes detailed analysis of the conveyor belt deflection under pragmatic load conditions. The aim of the project is to develop a Finite Element Method (FEM) simulation model for the deflection analysis of a conveyor belt using load data for bulk material calculated by a coupled Discrete Element Method (DEM) simulation. The scope of this project is on idler roll aspects. Two types of three-trough idlers were used in this project which were made of steel and plastic respectively. A variety of idler spacing were used to determine the most efficient configuration for the belt. This paper will explain the FEM procedures for the modelling of the belt behavior and the working principle of a coupled FEM-DEM analysis. Experimental results were presented and compared based on parameters. Comparisons showed plastic idler-rollers with smaller gap is better than the rest and it could be optimized to improve the performance and efficiency.

Electromechanical wave systems for mineral extraction

The problems of the development of mineral deposits related to the technologies of extraction, transportation and processing of viscous, gaseous and bulk materials, including in mixed fractions, are analysed. To solve the problem of efficient transport technologies, a combination of electromagnetic effects with a bionic approach based on the use of the principles of motion dynamics of dolphins, fish and amphibians with a wave-like swimming method is proposed. The purpose of the study is to develop a structural, object-oriented mathematical model of a channel-type wave electromechanical converter that provides transportation and processing of minerals in liquid, viscous, gaseous and mixed fractions. It is noted that in this case, the existing methods of development and calculation of traditional electric drives are not suitable since the electromagnetic core must have a different spatial arrangement and have a distributed structure, the configuration of which is individual. The construction of a structural bionic model of an electromechanical system is based on the use of a system of travelling wave equations with fixed ends and the principles of the genetic concept in electromechanics. By directional application of genetic and geometric operators to flat and cylindrical forms of electromagnetic field sources, populations of a flow channel and combined structures connected to the ends of a travelling wave are obtained. An object-oriented mathematical model, methodology and algorithm for calculating a multi-motor electromechanical converter integrated into the design of a transport wave system have been developed. The optimal ratios of copper and steel of the electromagnetic core, the geometric dimensions of the flow channel and the number of switched electromagnetic modules providing energetically efficient generation of a travelling wave in the channel are established. The study's theoretical significance lies in the fact that the results obtained can be used in the development of technologies and the design of devices for the transportation and processing of liquid, viscous, gaseous, bulk materials and mixed fractions in the mining industry and in other areas.

(Invited, Digital Presentation) Transport Characterization in Nano and Micron-Sized Multi-Component and Multi-Functional Materials

Porous and heterogeneous materials are core components in energy conversion and storage devices such as batteries, fuel cells and electrolyzers, or photoelectrochemical fuel generators. The heterogeneity and structural complexity of: i) the multi-functional nature of the applications requiring the presence of various functional materials in close vicinity, ii) nano- and micron-scale structuring of the material required to overcome the bulk material transport limitations, and iii) cheap and simple synthesis methods resulting in stochastic and complex morphologies. Understanding of the multi-physical transport phenomena and optimization of the component for enhanced performance, requires an accurate modelling and prediction of the transport properties, which heavily rely on the complex nano to micron-scale morphology.In this presentation, I will show how tomography-based direct numerical simulation scan be used for the accurate numerical characterization of the heterogeneous components’ transport properties. We will use X-ray micro-tomography for the characterization of the (thermal) transport in partially saturated gas diffusion layers/electrodes or in porous thermochemical reactors, and FIB-SEM nano-tomography for the multi-physical transport characterization of photoelectordes for water splitting and catalyst layers of CO2 reducing gas diffusion electrodes. I will show how we have built up a digital library of (photo)electrodes. Furthermore, I will show how machine learning approaches can be used to guide the design of optimized structures.