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Sökning: WFRF:(Asbjörnsson Gauti 1985)

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1.
  • Bhadani, Kanishk, 1991, et al. (författare)
  • Applied Calibration and Validation Method of Dynamic Process Simulation for Crushing Plants
  • 2021
  • Ingår i: Minerals. - : MDPI AG. - 2075-163X. ; 11:9
  • Tidskriftsartikel (refereegranskat)abstract
    • There is a need within the production industry for digitalization and the development of meaningful functionality for production operation. One such industry is aggregate production, characterized by continuous production operation, where the digital transformation can bring operational adaptability to customer demand. Dynamic process simulations have the ability to capture the change in production performance of aggregate production over time. However, there is a need to develop cost-efficient methodologies to integrate calibrations and validation of models. This paper presents a method of integrating an experimental and data-driven approach for calibration and validation for crushing plant equipment and a process model. The method uses an error minimization optimization formulation to calibrate the equipment models, followed by the validation of the process model. The paper discusses various details such as experimental calibration procedure, applied error functions, optimization problem formulation, and the future development needed to completely realize the procedure for industrial use. The validated simulation model can be used for performing process planning and process optimization activities for the crushing plant's operation.
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2.
  • Gröndahl, Albin, 1994, et al. (författare)
  • Impact of Feeding Position on Power Draw and Size Reduction in a Cone Crusher
  • 2017
  • Ingår i: The 15th European Symposium on Comminution and Classification.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The power draw of cone crushers, used in comminution and aggregates production, is in most cases monitored with too low sampling rate in comparison to the operating speed. This does not give adequate information on the actual operation mode and performance of the crusher during a full rotation of the eccentric motion of the mantle, leaving variance in the power draw unnoticed. This investigation has utilized a high speed measurement system for power draw on a lab scale cone crusher in order to identify an induced miss alignment in the feed, which is a common operation phenomenon, and the consequences of it. The results show that variations in the feeding alignment can be diagnosed and identified using only power draw measurements and that there are possibilities to use the approach for future control systems to improve fatigue life, operating efficiency, production yield and liberation in comminution processes.
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3.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • A Training Simulator for Crushing Plant Operators
  • 2012
  • Ingår i: XXVI International Mineral Processing Congress (IMPC 2012: Innovative Processing for Sustainable Growth; New Delhi; India; 24 September 2012 through 28 September 2012). - 9788190171434 ; , s. 2164-2171
  • Konferensbidrag (refereegranskat)abstract
    • Crushing plants are widely used around the world as a pre-processing step in the mineral and mining industries and as standalone processing plants in the aggregates industry. Despite automation and different advanced model predictive control a lot of the process is still managed by operators. The operators affect a lot of the performance. The numbers of the improvement they can achieve are at least as big as the advanced control algorithms’, today. Therefore it is also important to train the operators so they know how to behave in different situations. Models for crushers and other production units have been developed during the years and the latest add is the different units’ dynamic behavior being brought in, which gives the crushing plants dynamic time dependant performance. This can be used as a simulator for operators training. By connecting a Human Machine Interface (HMI) to a dynamic simulator with the models incorporated, a training environment for operators can be achieved. In this paper a dynamic crushing plant simulator implemented in MATLAB/SIMULINK has been connected to an HMI via a PLC. The HMI is placed in a control room at the university and complemented with monitors showing sequences from the process connected to the simulations, thus creating a realistic control room for training. In the created training environment the operators can be trained under realistic conditions. Simple training scenarios and how they could be simulated are discussed. Apart from the increased level of knowledge and experience among the operators, the time is an important factor. While a real crushing plant is still being built, the operators to be can already be trained, saving a lot of the commissioning time.
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4.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • An On-line Training Simulator Built on Dynamic Simulations of Crushing Plants
  • 2013
  • Ingår i: IFAC Proceedings Volumes (IFAC-PapersOnline). - 2405-8963. - 9783902823427 ; 15:1, s. 218-223
  • Konferensbidrag (refereegranskat)abstract
    • Crushing plants are widely used around the world as a pre-processing step in the mineral and mining industries or as standalone processing plants for final products in the aggregates industry. Despite automation and different types of advanced model predictive control, many the processes are still managed by operators. The skill of the operators influences the process performance and thus production yield. Therefore, it is important to train the operators so they know how to behave in different situations and to make them able to operate the process in the best possible way. Different types of models for crushers and other production units have been developed during the years and the latest improvement is the addition of dynamic behavior which gives the crushing plants a time dependent behavior and performance. This can be used as a simulator for operators training. By connecting an Internet based Human Machine Interface (WebHMI) to a dynamic simulator with the models incorporated, an on-line training environment for operators can be achieved. In this paper, a dynamic crushing plant simulator implemented in MATLAB/SIMULINK has been connected to a WebHMI. The WebHMI is accessible via the Internet, thus creating a realistic control room for operators’ training. In the created training environment, the operators can be trained under realistic conditions. Simple training scenarios and how they could be simulated are discussed. Apart from the increased level of knowledge and experience among the operators, the time aspect is an important factor. While a real crushing plant is still being built, the operators to be can already be trained, saving a lot of the commissioning and ramp up time.
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5.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Application of Design of Experiments (DoE) in Evaluating Crusher Circuit Performance
  • 2023
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The configuration and the interaction between the crushers and screens enable aggregate producers to produce products that are in accordance with the applicable product certification. However, the performance of the system is seldom optimized for the given conditions and market demand. This paper aims to describe the experimental work and the results of quantifying the crusher and screen performance by applying design of experiments in a full-scale tertiary crushing process of an aggregate production plant with both standard belt-cut sampling as well with continuous processes monitoring. The research output is able to demonstrate that there exists an interaction effect between the crusher closed side setting and eccentric speed that previously has not been identified with traditional methods. The quantification of interaction between crusher and screen individual performance to the process performance have been demonstrated with both belt-cut samples and continuous process monitoring.
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6.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Application of the Hilbert Transform for Diagnostic and Control in Crushing
  • 2020
  • Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875. ; 147
  • Tidskriftsartikel (refereegranskat)abstract
    • The performance of a crusher is an essential element in achieving efficient production of aggregates or metals. The process performance depends on the design and configuration of each process equipment, the configuration of the plant, the design of the control and physical properties of the incoming feed. Crushers, however, do not operate in an ideal condition, and as a result, the crusher’ structure, electrical drive and hydraulic system will experience an uneven load during operation. This paper aims to adapt a Hilbert transform to characterise the pressure variations in actual crushers during operation and to set up potential strategies for quantifying the variation. Two applications are also proposed for how this could be used in operation to compensate for the disturbances from unwanted loading conditions that affect the crusher performance.
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7.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Comminution process modelling from a sustainability perspective
  • 2018
  • Ingår i: 11th International Comminution Symposium (Comminution '18). - 9781510883789
  • Konferensbidrag (refereegranskat)abstract
    • Mining is one of the largest industries in the world and contributes largely to the environmental emissions as well as gross domestic product growth for many countries. The demand for sustainability in the industry is continuously increasing with efforts such life cycle assessment, circular economy and even fairtrade to improve the entire supply chain from different perspectives. The process of comminution is subjected to different conditions and will influence the performance of the process and utilization of resources. In this paper the aim is to simulate comminution circuit from an operational perspective with dynamic simulations to evaluate process performance and environmental impacts and to compare it to a cradle-to-gate process. By integrating the environmental impacts into the dynamic process simulations, a higher simulation fidelity can be achieved to provide an extended operational and environmental perspective to the process assessment.
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8.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Continuous Assignment Development on Topology Optimization in Engineering Design
  • 2022
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • An engineering course assignment needs to be designed as a stimulating and challenging task for actively engaging students. It is typically required to be solved in an iterative approach using lectures, reading materials, software tools and supervision sessions. Assignments allow for a practical application of a theory to enhance the students’ understanding of the topic with active learning activities to gain continuous engagement in the course. In the Engineering Design and Optimization course at the Chalmers University of Technology, there is a good balance of theoretical lectures and practical aspects in the assignments. One of these assignments is called the cantilever beam challenge. The students are given an iterative task of designing a cantilever beam based on their previous engineering know-how in the first iteration and applying Topology Optimization on a defined design space to minimise compliance and mass in the second set of iterations. This paper aims to examine the students’ performance, from the start of the course, concerning the development that has happened regarding the different software solutions and different additive manufacturing techniques, and to provide the students’ opinions on the assignment. Each year, this particular assignment ranks high in the course evaluation due to its framework, competitiveness and instant feedback on the proposed design solutions with computer analysis and physical experiments with 3D printed models. However, the interesting questions are whether more advanced tools and algorithms support students learning and whether the beams’ performance improves.
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9.
  • Asbjörnsson, Gauti, 1985 (författare)
  • Crushing Plant Dynamics
  • 2015
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The performance of a crushing plant is an essential element in achieving efficient production of aggregates or metals. A crushing plant´s operating performance depends on the design and configuration of each individual process unit, the configuration of the plant, the design of the control system, events occurring in the process and the physical properties of the incoming feed. The production process is a continuous process and as such it is also subjected to variations and changes in performance depending on the condition of the process. Crushing plants however, are traditionally simulated with steady-state simulation models which are not capable of predicting these conditions. A different technique is therefore necessary in order to estimate the actual behaviour of the plant with respect to time.Crushing plants are affected by both gradual and discrete changes in the process over time which alters the performance of the entire system, making it dynamic. A dynamic simulation is defined in this thesis as continuous simulations with sets of differential equations with static equations to reproduce the dynamic performance of a system. In this thesis multiple operational issues have been identified in order to achieve adequate process fidelity for simulation purposes. These operational issues have been addressed by introducing methods and models for representing different dynamic aspects of the process. These include: different types of bins to handle misaligned feeding, segregation and different flow behaviour, the use of system identification to measure actuator response to accurately estimate unit response, wear estimation for crushers, mechanistic models for crushers and screens for more accurate estimation of unit dynamics, segmented conveyors that can estimate material flow for conveyors with variable speed drives, parameter selection for optimum process performance, discrete events that occur within the process and different control strategies to capture the process dynamics.Different applications for dynamic simulation have been explored and demonstrated in this thesis. These include: process evaluation, control development, process optimization, operational planning, maintenance scheduling and operator training. Each of these areas puts different constraints on the modelling of crushing plants and the level of fidelity, which is determined by the purpose of the simulation.In conclusion, dynamic simulation of production processes has the ability to provide the user with in-depth understanding about the simulated process, details that are usually not available with static simulations. Multiple factors can affect the performance of a crushing plant, factors that need to be included in the simulation to be able to estimate the actual plant performance.
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10.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Development of a cognitive supporting operator training environment
  • 2014
  • Ingår i: 27th International Mineral Processing Congress, IMPC 2014, Santiago, Chile, 20-24 October 2014.
  • Konferensbidrag (refereegranskat)abstract
    • In aggregate production and mining the operators are responsible for controlling and monitoring the process to maintain high plant throughput and safe operation. Operators have to make different decisions to control the process due to changed demand on the operation from both management and conditions of the process. The quality of the response and the time it takes for an operator to respond to altered demand relies on what information is available and the experience of the operator.In this work a dynamic simulation platform has been developed to be used for operator training. Models for representing production units and process control for plant simulations have been developed and implemented in MATLAB/SIMULINK to simulate time-dependent plant behavior. Stochastic and scheduled events are included using the discrete events simulation toolbox SimEvents. The human-machine interface was developed using the human-machine interface software ICONICS. The operators’ cognitive process, in interpreting the plants semantic, has been studied by observations and with informal interviews with operators. This was done to get information about the daily operation and the problems that occur in the process. By interacting with operators that experience different physical interactions with the process; more qualitative e-learning software for supporting operator training in a dynamic operator environment could be developed. The quality of the operator training environment was evaluated with a usability study that was performed with operators and others within the production.
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11.
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12.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Development of production and environmental platforms for the European aggregates and minerals industries
  • 2024
  • Ingår i: Minerals Engineering. - 0892-6875. ; 206:2024
  • Tidskriftsartikel (refereegranskat)abstract
    • Both quantification and communication of environmental impacts can create the foundation for improved sustainable production and decision-making. Without widespread information about site-specific environmental impacts, stakeholders cannot make a well-informed decision based on the local system boundaries. With organization-wide digital platforms, different aspects of production and management can be integrated and customized based on the organization's needs. This paper aims to give an overview of the development of three different process and environmental platforms, their purposes, system structure, system constraints and the applied framework. These respective platforms are being developed separately for the Swedish aggregates industry, the European aggregates industry and the European critical raw materials sector. The initial demonstrator can integrate site-specific information with a simulation-based allocation of resources and generate Life-Cycle Assessment and Environmental Product Declaration reports harmonized with the EN 15804 standard and the associated Product Category Rules.
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13.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Development of Production and Environmental Platforms for the European Aggregates and Minerals Industries
  • 2023
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Both quantification and communication of environmental impacts can create the foundation for improved sustainable production and decision-making. Without widespread information about site-specific environmental impacts, stakeholders cannot make a well-informed decision based on the local system boundaries. With organization-wide digital platforms, different aspects of production and management can be integrated and customized based on the organization's needs. This paper aims to give an overview of the development of three different process and environmental platforms, their purposes, system structure, system constraints and the applied framework. These respective platforms are being developed separately for the Swedish aggregates industry, the European aggregates industry and the European critical raw materials sector. The initial demonstrator can integrate site-specific information with a simulation-based allocation of resources and generate Life-Cycle Assessment and Environmental Product Declaration reports harmonized with the EN 15804 standard and the associated Product Category Rules.
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14.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Different perspectives of dynamics in comminution processes
  • 2022
  • Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875. ; 176
  • Forskningsöversikt (refereegranskat)abstract
    • The performance of a comminution and classification process depends on the design and configuration of each process unit, the configuration of the plant, the design of the control and physical properties of the incoming feed. Comminution processes should be designed to have a stable and efficient production over a wide range of conditions. However, demands from the management, operational cost, investment, maintenance or any other related field can result in process alterations that are not beneficial for the stability of the circuit and, therefore, utilization and efficiency of the production. Furthermore, advanced process control and optimization rely heavily on understanding the dynamic behaviour of the process in achieving a more stable and consequently efficient process. This review aims to explore different dynamic aspects from particle, bulk, unit and process perspectives, their origin, and what consequences they may have on the operation. The aim is to illustrate a holistic view of process dynamics that should be considered when evaluating circuit performances and identifying risk zones that affect the process, considering the state-state performance and dynamic behaviour. Based on that, several dynamic related issues were formulated and ranked by experts within the field to get a subjective perspective. Issues such as process control design and configuration, ore variability, segregation and upstream disturbances ranked high in possible gains for comminution processes.
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15.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Implementation of Dynamic Simulation at Anglo Platinum
  • 2014
  • Ingår i: 9th International Comminution Symposium 2014.
  • Konferensbidrag (refereegranskat)abstract
    • The dynamics of process operation can be overlooked in design; often with considerable loss of throughput resulting from dynamic fluctuation and mismatch of units across a circuit. As a consequence, higher demand is on design of different control strategies. Designing a circuit with consideration of the implications an operation and control strategies have on the process is essential.The aim of this paper is to describe the modelling work done for this application and give an overview of the implementation of dynamic simulation platform at Anglo Platinum to support future debugging and tuning of the Advanced Process Control for a planned expansion. This paper builds on previous dynamic modelling work done at the Mogalakwena North Concentrator. The work is focused on system identification and the implementation of the Advanced Process Control algorithm in the dynamic plant model. The dynamic model of the plant was connected to the Advanced Process Control system and the response of the model validated against the behaviour of the plant.
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16.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Importance of crusher control and cloud computing process monitoring of crushers
  • 2019
  • Ingår i: IMCET 2019 - Proceedings of the 26th International Mining Congress and Exhibition of Turkey. ; 2019, s. 873-876
  • Konferensbidrag (refereegranskat)abstract
    • The main task of a crusher control system is to keep production on a desired level while simultaneously protecting the crusher from overload and fatigue failure. A stable production can be achieved through control of the crusher's closed side setting (CSS), which implies compensation of the wear of the crusher liners. A further objective is to provide with the possibility to optimize operational performance and utilization. For an efficient system the sampling rate needs to be sufficiently high and the control and optimization algorithms need to be robust. In addition, and equally important, configuration of the electrical cabinet and wiring must be able to withstand the harsh environment over time. Modelling and simulation of cone crushers have been on-going at Chalmers University of Technology during the last 25 years. With time the research has expanded to include several different aspects of cone crusher operation, design optimisation, real-time control and product yield optimization. As a consequence, a strong need for dedicated control possibilities of cone crushers have risen. The requirement for precise control led to the development of a new system for cone crusher control which was named Crusher Control Unit or CCU. The system has been further developed by Roctim to provide an independent, modular and flexible development platform for different crusher types. A unique feature is that the CCU can be retrofitted to both Hydrocone type of cone crushers as well as to Symons type independent of brand or age of the crusher. In order to remotely monitor the crusher performance and retrieve data from the CCU a cloud based solution has been developed.
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17.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Improving Students Engagement with Active Learning in Engineering Optimization Lectures
  • 2021
  • Ingår i: Proceedings of the International CDIO Conference. - 2002-1593. - 9786164076167 ; 1:1, s. 535-545
  • Konferensbidrag (refereegranskat)abstract
    • In optimisation, as for learning, the synthesises of previous knowledge and current information is essential to achieve defined objectives. The students' objectives are to fulfil the course's intended learning outcomes and possibly, at the same time, develop their knowledge, skills, and attitudes within the subject. The purpose of this work is to incorporate a more collaborative learning environment with active learning activities in the classroom to improve student learning opportunities, their perception of the course and their interest in the subject of optimisation. Within the CDIO initiative, active learning or experiential learning is stated as a key factor in engaging students directly in thinking and problem-solving activities. This can apply to different teaching activities such as assignments, lectures, and assessments. With active learning, the purpose is to involve students more actively in the learning process instead of relying on passive information transfer. Active learning methods aim to facilitate the students' process of creating their understanding of the topic by reflecting, questioning, conjecturing, evaluating and make connections between ideas whilst drawing on ideas, experiences and knowledge of others. In this work, diverse activities for incorporating more interactive learning in the classroom have been implemented in different course lectures, activities such as think pair-share, mind maps, multiple-choice questions, incomplete hands and more. An evaluation of the students' perception of the course and the various activities was carried out at the end of the course. The most considerable improvement was with the overall impression of teaching. That improved between the years from 3.10 to 3.57. The most appreciated activity was the think-pair-share approach, which gave the students a cognitive break from the lecture slides to discuss the topic. However, the response rate was limited but did indicate the students' perspective and what was appreciated. The results will provide a good base for future development.
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18.
  • Asbjörnsson, Gauti, 1985 (författare)
  • Modelling and Simulation of Dynamic Behaviour in Crushing Plants
  • 2013
  • Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Crushing plants are a vital part in the production of aggregates and metals. Plants are traditionally simulated with a steady-state simulation. With steady-state simulation the plant is simulated until equilibrium is achieved. However, crushing is a continuous process and as such it is subjected to variations and changes in performance depending on the dynamics of the system. A different technique is therefore necessary to estimate the real behaviour of the plant.The main hypothesis in this research is that crushing plants are affected by both gradual and discrete changes in the process which alter the performance of the entire system, making it dynamic. A dynamic simulation is defined here as continuous simulations with sets of differential equations to reproduce the dynamic behaviour of a system. Crushing plants experience different operating performance depending on the configuration of each individual process unit, the configuration of the plant, the design of the control system, events occurring in the process and additional disturbances. Three different application areas for dynamic simulation have been demonstrated in this thesis: plant performance, process optimization and operator training. Each of these areas put different constraints on the modelling and simulation of crushing plants.Traditional steady-state plant simulations are able to provide an overall estimation of the ideal performance. Plants can however experience changes in performance during operation. Plant simulation for an unstable plant has been performed in order to increase the level of stability of the operation. Simulations and experiments of different operational strategies revealed that a higher level of stability was possible with different configuration on specific production units.Development of control systems is important for the operating conditions in a crushing plant. Real-time optimization is a relatively new field in aggregate production which aims to optimize the production in real-time with the help of advanced process control algorithms. One way of achieving this is with a Finite State Machine. By connecting a Finite State Machine algorithm to a dynamic simulator, tuning of the control parameters becomespossible. Even though only a marginal improvement was estimated with optimized parameters, located with a genetic algorithm, it is an important step in control system development.The system structure required to enable operator training was built in the Chalmers Rock Processing System laboratory. The fundamental framework around the system is built on the dynamic simulator. The process is simulated in real-time and information from the simulated process is communicated to a Human Machine Interface and a Programmable Logic Controller. With this system, different scenarios can be simulated to assist the operator in gaining knowledge and experience.In conclusion, dynamic simulation of production processes has the ability to provide the user with deeper understanding about the simulated process, details that are usually not available with traditional steady-state simulations. Multiple factors can affect the performance of a crushing plant, factors that need to be included in the simulation to be able to estimate the actual plant performance. The dynamic response of a system is determined by the characteristics of the system involved and the changes in the process.
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19.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Modelling Dynamic Behaviour of Storage Bins for Material Handling in Dynamic Simulations
  • 2012
  • Ingår i: XXVI International Mineral Processing Congress (IMPC 2012: Innovative Processing for Sustainable Growth; New Delhi; India; 24 September 2012 through 28 September 2012). - 9788190171434 ; , s. 258-267
  • Konferensbidrag (refereegranskat)abstract
    • Material handling is an essential part of the aggregate and mining industries. Mixing and blending of granular material can affect the grading and particle size distribution of the material leaving the system. Segregation and variability can cause problems in the downstream process while insufficient capacity will disturb upstream processes.Process plants utilize surge bins for handling recycle streams of material and act as a buffer for the process. The flow through the surge bin is usually controlled by a simple PID controller or PID controller in combinations with a plant-wide controller. Even though the surge bins play an important role of smoothening out the plant and creating a steady operating condition are they seldom included in plant simulations. This can lead to a number of problems in the form of decreased plant capacity, plant lockdown, and even operation units malfunctioning. The main objective of this study is to investigate the dynamic behavior in surge bins and develop a model more suitable for representing this behavior, which can occur during operation, for dynamic simulations. The proposed model adopts vertical layers which allow for flows between segments depending on the level of neighboring segments. This enables both the representing of segregation within the system and gives an indication on the effects from different inlet- and outlet placements. The proposed model was developed in Matlab/Simulink and validated against an actual bin with the total capacity of 700 m3 in platinum ore application. With the new bin model significantly higher fidelity and more accurate dynamic simulation results were achieved.
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20.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Modelling & dynamic simulation of gradual performance deterioration of a crushing circuit - including time dependence and wear
  • 2012
  • Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875. ; 33, s. 13-19
  • Tidskriftsartikel (refereegranskat)abstract
    • The use of steady-state models in process simulation is a well-established method in many process industries. Designing a large crushing plant by relying on steady-state simulations alone will not generally provide the full picture of possible operational performance. The dynamics and variation between equipment and stochastic events can significantly reduce predicted plant performance. In order to dynamically simulate the crushing circuit, models for process equipment need to be further developed.The purpose of this paper is to create a wear function for an existing Particle Size Distribution model (i.e., a Swebrec-function) with data obtained from a real crusher operating at gradually increasing closed side settings. This is done to create an accurate and updated model of the crusher in which the transient consequences of wear are captured. The Swebrec-function and correlation model were implemented into simulation software with simulated events; this simulation was validated with actual process readings. Improved simulations were then attained with the developed functions.
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21.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Modelling environmental impacts of aggregates with dynamic simulations
  • 2017
  • Ingår i: Proceedings of the 15th European Symposium on Comminution and Classification (ESCC2017).
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Aggregates production is one of the largest industries in the world and contributes largely to the global environmental emissions. To estimate different product environmental footprint, the industrial standard is to use the life cycle assessment (Bart et al.) to quantify their impact on the environment. In 2011, the environmental product labels and declarations standard ISO14025 (EPD) was initiated to create transparent and comparable information for consumers. This is becoming increasingly common in Sweden for constructions and infrastructure projects, with certain limitations. The process of producing aggregates is subjected to different conditions and setup that will influence the performance of the plant as well as the utilization of energy.In this paper the aim is to simulate different processes for aggregate production from an operational perspective to evaluate process performance and environmental impact for different scenarios. The objective is to model and simulate the process with dynamic process simulations to capture the accumulated environmental footprint and its variation of the different product as they are produced. An approach for estimating the environmental footprint within established dynamic simulation platform is presented and demonstrated. The proposed modelling approach demonstrates a systematic way to evaluate the process performance and quantifying the life cycle inventory (LCI) for given conditions. The developed models can be used to optimize the different aspects of the operation depending on the defined objective function and the system boundaries. Simulating the process by manipulating configuration of the entire process has been illustrated in this paper. By integrating the environmental impacts into the dynamic process simulations, a higher simulation fidelity can be achieved to provide an extended operational perspective to the optimization and improve process analysis.
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22.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Modelling of Discrete Downtime in Continuous Crushing Operation
  • 2016
  • Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875. ; 98, s. 22-29
  • Tidskriftsartikel (refereegranskat)abstract
    • © 2016 Elsevier Ltd Crushing is a harsh process and production units are subjected to wear and failure over time which will reduce the overall performance of the plant. To achieve optimum process performance, both time dependant process dynamics and operating conditions should be taken into account. In this paper the aim is to simulate the process from a more operational perspective to evaluate process performance and process optimum for different operations. The objective is to model and simulate the discrete phenomena that can cause the process to alter performance and implement it with dynamic process simulations. An approach for combining discrete event simulations with time-dependent simulations for process evaluation and optimization is presented. The proposed approach demonstrates a systematic way to evaluate the process performance and locating optimum process configuration, for a given condition. The developed models can be used to optimize different aspects of the operation depending on the defined objective function and the system boundaries. Optimization of process throughput by manipulating configuration of both the grizzly and the crushers, as well as the time between calibrations has been illustrated in this paper. Adjusting the process continuously and calibrating it at the appropriate time can have major benefits when it comes to the process availability and utilization, increasing performance by 4.1–9.3% in these cases. Evaluation of process robustness and availability with regards to process specific factors and variation gave an indication of the process and unit performance under a long operating period. By combining discrete and dynamic simulation, a higher simulation fidelity can be achieved to provide a more operational perspective to the optimization and process analysis.
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23.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Modelling of Discrete Downtime in Continuous Crushing Operation
  • 2015
  • Ingår i: Computational Modelling 2015, MEI conference.
  • Konferensbidrag (refereegranskat)abstract
    • Crushing is a harsh process and production units are subjected to wear and failure over time which will reduce the overall performance of the plant. To achieve optimum process performance, both time dependant process dynamics and operating conditions should be taken into account.In this paper the aim is to create a framework for simulating the process from a more operational perspective to evaluate process performance and process optimum for different operational scenarios. The objective is to model and simulate the discrete phenomena that can cause the process to alter performance and implement it with dynamic process simulations. A method for combining discrete probability simulations with time-continuous simulations for process evaluation and optimization is presented. The proposed framework demonstrates a systematic approach to evaluate the process performance and locating optimum process configuration, for a given condition. The developed models can be used to optimize different aspects of the operation depending on the defined objective function and the system boundaries. Optimization of process throughput by manipulating configuration of both the grizzly and the crushers, as well as the time between calibrations has been illustrated in this paper. Adjusting the process continuously and calibrating it at the appropriate time can have major benefits when it comes to the process availability and utilization, increasing performance by 4.1-9.3 % in these cases. Evaluation of process robustness with regards to different maintenance strategies and process variation gave an indication of the process and unit performance under a long operating period. By combining discrete and dynamic simulation, a higher simulation fidelity can be achieved to provide a more operational perspective to the optimization and process analysis.
  •  
24.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Modelling & Simulation of Dynamic Crushing Plant Behaviour with MATLAB-Simulink
  • 2013
  • Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875. ; 43-44:Special Issue: SI, s. 112-120
  • Tidskriftsartikel (refereegranskat)abstract
    • Every process is subjected to changes in performance and efficiency over time. These dynamics can originate upstream and be inherent through the process or occur anywhere in the downstream process. Traditional plant simulations are performed with steady-state simulation, which are limited to give the performance in an ideal situation. However, plant performance usually tends to deviate away from the predicted plant performance. These dynamics are usually consequences of an altered state of the plant due to factors such as natural variation, unmatched, inappropriate or degrading equipment performance and/or stochastic events. This paper presents a novel approach for simulating dynamic plant behavior and evaluating effects from process modification through dynamic simulations with MATLAB/Simulink. An example of an existing crushing circuit is used to illustrate the functionality and the advantage of using a dynamic simulator. The results and knowledge gained from the simulation can provide a base for optimizing a robust production output in the form optimal utilization, energy efficiency or higher product quality.
  •  
25.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Modelling & Simulation of Dynamic Crushing Plant Behaviour with MATLAB-Simulink
  • 2012
  • Ingår i: 8th International Comminution Symposium.
  • Konferensbidrag (refereegranskat)abstract
    • Every process is subjected to changes in performance and efficiency over time. These dynamics can originate upstream and be inherent through the process or occur anywhere in the downstream process. Traditional plant simulations are performed with steady-state simulation, which are limited to give the performance in an ideal situation. However, plant performance usually tends to deviate away from the predicted plant performance. These dynamics are usually consequences of an altered state of the plant due to factors such as natural variation, unmatched, inappropriate or degrading equipment performance and/or stochastic events. This paper presents a novel approach for simulating dynamic plant behavior and evaluating effects from process modification through dynamic simulations with MATLAB/Simulink. An example of an existing crushing circuit is used to illustrate the functionality and the advantage of using a dynamic simulator. The results and knowledge gained from the simulation can provide a base for optimizing a robust production output in the form optimal utilization, energy efficiency or higher product quality.
  •  
26.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Opportunities for the Application of Augmented Reality in Mining and Minerals Processing
  • 2020
  • Ingår i: IMPC 2020 Proceedings.
  • Konferensbidrag (refereegranskat)abstract
    • The mining and minerals processing industry is gradually being digitalized to improve efficiency and reduce waste. One aspect of this transition is to ensure that relevant process-data in sufficient quality and quantity is given to the operator in the right format and at the right time to improve decision-making. Augmented Reality (AR) can serve as a potential ICT-based support tool for human operators to achieve this goal. With AR, virtual information is combined with the real world in real-time. Thus, AR technology holds potential for fulfilling the need for improved data visualization in Industry 4.0. This article is the result of a collaborative effort of Chalmers University of Technology and RWTH Aachen University to identify selected state-of-the-art applications of AR that are currently being applied in the mining and minerals industry or selected related industries. This article aims at showing opportunities for the application of AR in the mining and mineral processing industry with selected conceptual applications. This article concludes with several requirements identified as necessary to implement the conceptual applications of AR in the mining and minerals industry.
  •  
27.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Quantifying Electrification Requirement of Mobile Crushing Units in Swedish SME Quarries
  • 2022
  • Ingår i: The proceedings of the 17th European symposium on comminution and classification.
  • Konferensbidrag (refereegranskat)abstract
    • The European aggregate industry faces the same challenges as other large industries in meeting the Agenda 2030 goals of net-zero emissions, as stated by the Sustainability Development Goal 13 [1]. In Sweden, the aim is to achieve this by 2045, where the intermediate goal is to have accomplished a 50 % reduction by 2030. As for most industries, the main focus is to investigate how to phase out fossil fuels and fossil-driven vehicles which can contribute with approximately 65 % of the greenhouse gas emissions for a medium size aggregates plant, for a smaller, off the grid, sites this will be higher. The other large contributors to greenhouse gas emission includes the explosives and electrical consumption of the equipment. How much the actual contribution from diesel to greenhouse gas emission depends on the selection and configuration of the heavy machinery, configuration of the process and the geological location of the site. This paper aims to describe the work done at Chalmers Rock Processing Systems and Stonepower AB within the first phase of Swedish Aggregates Producers Association project, Sustainable Smart Electrification of Small Quarries. The work aims to map out the crushers' electrical power requirements under different operating conditions in different quarries. This is to create a requirement specification for the development of a modular solution for more cost-effective battery-transformers package for a more economical feasible investment plan for smaller quarries.
  •  
28.
  • Asbjörnsson, Gauti, 1985, et al. (författare)
  • Understanding Different Perspectives of Dynamics in Comminution Processes
  • 2021
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The performance of a comminution and classification process depends on the design and configuration of each process unit, the configuration of the plant, the design of the control and physical properties of the incoming feed. Comminution processes should be designed to have a stable and efficient production over a wide range of conditions. However, demands from the management, operational cost, investment, maintenance or any other related field can result in process alterations that are not beneficial for the stability of the circuit and therefore utilization and efficiency of the production. Furthermore, advanced process control and optimization rely heavily on understanding the dynamic behavior of the process in achieving a more stable and consequently efficient process. The objective of this review is to explore different dynamic aspects from particle, bulk, unit and process perspectives, their origin, and what consequences they may have on the operation. The aim is to illustrate a holistic view of process dynamics that should be considered when evaluating circuit performances and identifying risk zones that affect the process, both considering the state-state performance as well as the dynamic behaviour.
  •  
29.
  • Asbjörnsson, Gauti, 1985 (författare)
  • Webbaserad Miljöverktyg för Svensk bergmaterialproduktion - EPD berg
  • 2021
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Bergmaterial är Sveriges till volymen största och också tyngsta industriprodukt med sina 100 miljoner ton producerade per år. Produktionen av dessa mäktiga volymer är inte kontinuerligt transparent ur vare sig ett miljöpåverkans- eller ett tekniskt perspektiv, trots dagens möjligheter att noggrant beräkna energiåtgång och emissioner. Detta gör att det heller inte går att styra produktionen med denna viktiga information.   Visionen med Vinnova projektet ”Utveckling av ett webbaserat EPD-verktyg för bergmaterialproduktion – EPD Berg” är at skapa ett gemensamt verktyg för branschen, både nationellt och internationellt, som kopplar ihop den faktiska produktionskedjan av bergmaterial med genomtänkta modeller, europeiska miljödatabaser och övriga tillgängliga EPD-system. En unik lösning som inte har någon motsvarighet på marknaden. Därmed erbjuds såväl producenter som samhälle ett gemensamt och accepterat sätt att beräkna miljöprestanda, presentera resultatet, och tolka miljöpåverkan. I förlängningen kommer både köpare och användare av bergmaterialprodukterna att ställa allt hårdare krav på producenterna som också med tiden kommer anpassa sig till situationen och tvingas vara proaktivt miljömedvetna i sina produktionsprocesser.   Målet för detta projekt är att utveckla ett webbaserat verktyget där olika intressenter kan skapa projekt erhålla relevant information om produktionen; beställaren kan få fram för-certifierad EPD-dokumentation för det producerade materialet; kommunen kan få en sammanställning över vilken miljöpåverkan som kommer ske den närmaste månaden i alla täkter i kommunen, privatkunden får en jämförelse av olika producenters produkt, inklusive transport; och platschefen på krossanläggningen kan få relevant information så dom kan ta informativt beslut för en potentiellt förbättrad produktion ur både miljö- och produktivitetssynvinkel.
  •  
30.
  • Bengtsson, Magnus, 1973, et al. (författare)
  • ADVANCED MATERIAL MODELLING IN CRUSHING PLANTS USING REAL TIME ALGORITHMS
  • 2015
  • Ingår i: Computational Modelling 2015, MEI conference.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • In process control of crushing plants the traditional control is focused on stability control ofsingle machines and not on controlling material utilization. The reason for this is that the use ofmaterial property models is not that well known. The material models describe properties as e.g.capacity over time for a given product and this may depend on many parameters and dynamic effectsin the process. Due to this it is complicated to model and thus a methodology is needed to solve thisproblem. In this paper a novel method for modeling the current effect that the production units haveon the material presented. The paper presents a methodology how to use process data from SCADAsystem to analyze and suggest dynamic material model properties in real time.
  •  
31.
  • Bengtsson, Magnus, 1973, et al. (författare)
  • Model of banana screen for robust performance
  • 2016
  • Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 91, s. 66-73
  • Tidskriftsartikel (refereegranskat)abstract
    • Screens are an important production unit in crushing plants. The performance of the screen is essential to the performance of the crushing plant. In this paper a mechanistic model of a banana screen is described and a novel model for screen deck configuration is presented. The developed model can be used for optimization of a screen so that it has the best possible performance with respect to different feeding conditions, in order to obtain a desired separation. The simulation results were compared to full scale test data and the conclusions from this comparison is that the screen model needs further parameters to handle the necessary screen deck configuration. An initial static model was derived to explain how the screen deck configuration will affect the screen efficiency. The modification of the screen deck parameters resulted in a better correlation both regarding size distribution and predicted capacity.
  •  
32.
  • Bengtsson, Magnus, 1973, et al. (författare)
  • Towards dynamical profit optimization of comminution circuits
  • 2017
  • Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 103, s. 14-24
  • Tidskriftsartikel (refereegranskat)abstract
    • There is an increasing demand to optimize performance and profit of comminution circuits. Research in this area has resulted in the development of numerous optimization tools, and recent research has shown that the quality aspects of the production have a great influence on the optimization results. The quality, cost, profit and capacity of a product are influenced by several parameters, and in order to control all of these parameters it is necessary to use some sort of optimization algorithm. In this paper, a novel approach to apply e.g. cost, revenue, capacity and quality in order to perform a multi objective optimization with the ability to handle dynamic variations of a comminution is presented. The problem with optimizations in general is that the objective function used for optimization is reduced in complexity in order to save computational time. In a comminution process performance varies with time and in order to perform a correct optimization the objective function used must be able to handle this type of dynamic behavior. The process has a given set of constraints that represents the conditions normal in these type of comminution applications. The first step in this paper is to identify if the range of the constraints can cause undesirable production costs when reaching for a given product property. In this step a dynamic response model is described that will be able to address the difficulties with optimizing dynamic systems. The next step in the optimization is the definition of the multi-objective optimization formulation including constraints for the optimization. Evaluating the result of the optimization in combination with a strategy for relaxing constraint can show how to increase overall productivity and still reach certain product properties. The conclusions made in this work are that multi objective optimization is essential when optimizing a comminution circuit against multiple objectives.
  •  
33.
  • Bhadani, Kanishk, 1991, et al. (författare)
  • Application of design of experiments (DoE) in evaluating crushing-screening performance for aggregates production
  • 2024
  • Ingår i: Minerals Engineering. - 0892-6875. ; 209
  • Tidskriftsartikel (refereegranskat)abstract
    • The configuration and the interaction between the crushers and screens enable aggregate producers to produce products that are in accordance with the applicable product certification. However, the performance of the system is seldom optimized for the given conditions and market demand. This paper aims to describe the experimental work and the results of quantifying the crusher and screen performance by applying the design of experiments (DoE) in a full-scale tertiary crushing process of an aggregate production plant with both standard belt-cut sampling as well with continuous processes monitoring. The results show the application of a simplified modelling approach using the design of experiments for the evaluation of crusher performance and circuit performance using experimental data. The research output is able to demonstrate that there exists an interaction effect between the crusher closed side setting and eccentric speed that previously has not been identified with traditional methods. The quantification of interaction between crusher and screen individual performance to the process performance has been demonstrated with both belt-cut samples and continuous process monitoring. Using a DoE, digital experiments can be planned for mapping and quantifying the performance of aggregate production.
  •  
34.
  • Bhadani, Kanishk, 1991, et al. (författare)
  • Application of Multi-Disciplinary Optimization Architectures in Mineral Processing Simulations
  • 2018
  • Ingår i: 11th International Comminution Symposium. - 9781510883789
  • Konferensbidrag (refereegranskat)abstract
    • Optimization is a pivotal point in distinguishing the competitiveness between industries that are developing, designing and operating products and processes. Mineral processing is an industry which operates various sub-processes and produces one or several products. The sub-processes involved are dynamic in nature and differs in discipline of operation. These dynamic sub-processes are sequentially integrated forming a mineral processing system. Currently, the developed simulations for the mineral processing systems have the potential to be used to design, operate and control mineral processing plants to an increased extent, but need broader optimization strategies to integrate multiple sub-processes involved. The scope of this research is to demonstrate application of multi-disciplinary optimization (MDO) architectures into a mineral processing simulation. A case study consisting of two sub-processes of comminution and classification circuits to produce aggregate products is used to demonstrate the application of MDO architectures. The MDO architectures are compared based on problem formulation, computational resources required and validity of the results. The optimization results using MDO architectures can be used to illustrate trade-offs between different sub-processes within the considered scope. The application of MDO architectures can facilitate the linking mathematical models of various disciplines such as comminution, and liberation in mineral processing simulation.
  •  
35.
  • Bhadani, Kanishk, 1991, et al. (författare)
  • Application of multi-disciplinary optimization architectures in mineral processing simulations
  • 2018
  • Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875. ; 128, s. 27-35
  • Tidskriftsartikel (refereegranskat)abstract
    • Optimization is a pivotal point in distinguishing the competitiveness of industries that are developing, designing and operating various products and processes. Mineral processing is an industry which operates various sub-processes and produces one or several products. The sub-processes involved are dynamic in nature and differ in the discipline of operation. These dynamic sub-processes are sequentially integrated forming a mineral processing system. Currently, the developed simulations for the mineral processing systems have the potential to be used to design, operate and control mineral processing plants to an increased extent, but need broader optimization strategies to integrate multiple sub-processes involved. The scope of this research is to demonstrate application of multi-disciplinary optimization (MDO) architectures into a mineral processing simulation. A simulation study consisting of two sub-processes of comminution and classification circuits to produce aggregate products is used to demonstrate the application of MDO architectures. The MDO architectures are compared based on problem formulation, computational resources required and validity of the results. The optimization results using MDO architectures can be used to illustrate trade-offs between different sub-processes within the considered scope. The application of MDO architectures can facilitate the linking mathematical models of various disciplines such as comminution, and liberation in mineral processing simulation.
  •  
36.
  • Bhadani, Kanishk, 1991, et al. (författare)
  • Application of Optimization Method for Calibration and Maintenance of Power-Based Belt Scale
  • 2021
  • Ingår i: Minerals. - : MDPI AG. - 2075-163X. ; 11:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Process optimization and improvement strategies applied in a crushing plant are coupled with the measurement of such improvements, and one of the indicators for improvements is the mass flow at different parts of the circuit. The estimation of the mass flow using conveyor belt power consumption allows for a cost-effective solution. The principle behind the estimation is that the power draw from a conveyor belt is dependent on the load on the conveyor, conveyor speed, geometrical design, and overall efficiency of the conveyor. Calibration of the power-based belt scale is carried out periodically to ensure the accuracy of the measurement. In practical implementation, certain conveyors are not directly accessible for calibration to the physical measurement as these conveyors have limited access or it is too costly to interrupt the ongoing production process. For addressing this limitation, a better strategy is needed to calibrate the efficiency of the power-based belt scale and maintain the reliability of such a system. This paper presents the application of an optimization method for a data collection system to calibrate and maintain accurate mass flow estimation. This includes calibration of variables such as the efficiency of the power-based belt scale. The optimization method uses an error minimization optimization formulation together with the mass balancing of the crushing plant to determine the efficiency of accessible and non-accessible conveyors. Furthermore, a correlation matrix is developed to monitor and detect deviations in the estimation for the mass flow. The methods are applied and discussed for operational data from a full-scale crushing plant.
  •  
37.
  • Bhadani, Kanishk, 1991, et al. (författare)
  • Comparative Study of Optimization Schemes in Mineral Processing Simulations
  • 2019
  • Ingår i: IMPC 2018 - 29th International Mineral Processing Congress. ; 2019, s. 464-473
  • Konferensbidrag (refereegranskat)abstract
    • Modelling and simulations for mineral processing plants have been successful in replicating and predicting predefined scenarios of an operating plant. However, there is a need to explore and increase the potential of such simulations to make them attractive for users. One of the tools to increase the attractiveness of the simulations is through applying optimization schemes. Optimization schemes, applied on mineral processing simulations, can identify non-intuitive solutions for a given problem. The problem definition itself is subjective in nature and is dependent on the purpose of the operating plant. The scope of this paper is to demonstrate two optimization schemes: Multi-Objective Optimization (MOO) using a Genetic Algorithm (GA) and Multi-Disciplinary Optimization (MDO) using an Individual Discipline Feasible (IDF) approach. A two stage coarse comminution plant is used as a case plant to demonstrate the applicability of the two optimization schemes. The two schemes are compared based on the problem formulations, types of result and computation time. Results show that the two optimization schemes are suitable in generating solutions to a defined problem and both schemes can be used together to produce complementary results.
  •  
38.
  • Bhadani, Kanishk, 1991, et al. (författare)
  • Development and implementation of key performance indicators for aggregate production using dynamic simulation
  • 2020
  • Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875. ; 145
  • Tidskriftsartikel (refereegranskat)abstract
    • Continuous process improvements are needed to maintain and run an industrial operation at a profitable state. An aggregates production plant consists of multiple process operations such as blasting, primary crushing, followed by secondary and tertiary crushing stages with an intermediate screening of products. Each of these processes can be operated with multiple objectives in mind of operators and plant managers. These objectives can be defined by varying terms like generating required throughput of the plant, maintaining equipment’s health, meeting customers’ demands, etc. The use of the term key performance indicators is recurrent in industry to formalise and represent these objectives of operation. Currently, the KPIs defined by the ISO 22400 standards are widespread for continuous improvements in the manufacturing industry and they are viewed as a support tool to measure improvements. The scope of this paper is to calculate relevant KPIs for an aggregates production plant using dynamic simulations. Further, the KPIs are implemented in a three-stage aggregate production plant using both real-time plant data and dynamic process simulation. The KPIs developed are useful for operators and plant managers to make decisions. The results show the relationship and dependencies of various equipment and process KPIs. The dynamic simulation has potential to be used as an exploration tool to identify the opportunities of improvement in aggregates processing using KPIs as a measure. The KPIs presented in the paper are based on ISO 22400 standard and have potential to be extended to similar processing operations such as coarse and fine comminution for minerals processing. Apart from the diagnostics application, the KPIs implemented in the dynamic simulation platform can be used to explore and optimize a crushing plant’s design and operations.
  •  
39.
  • Bhadani, Kanishk, 1991, et al. (författare)
  • Experimental and simulation-driven improvements for coarse comminution circuit using Plantsmith process simulator - A case study of Geita Gold Mine, Tanzania
  • 2021
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Continuous improvements are a key aspect of driving an industrial process plant at a profitable state. The performance of the crushing plant is driven by each equipment’s (crusher, screen conveyors, bin, etc.) operation, raw material properties, operational strategies, control system, maintenance, and so on. To bring improvements for full-scale industrial units, a thorough investigation is needed. In the considered case study, a need was posed by the industry operating coarse and fine comminution circuit to investigate the opportunities for upscaling and downscaling of the plant capacity along with evaluating the performance of the existing circuit. The need is driven by the change in ore characteristics from the mining segment. As the decision’s in the industry is driven by the cost, it is important to find opportunities which will increase the profitability and produces a viable solution(s). The paper presents a methodological approach for evaluating the performance of the crushing plant by carrying out: • Physical investigation and observation • Experimental survey and laboratory data analysis • Evaluating historical production data • Simulation configuration and calibration in Plantsmith process simulator • Evaluating alternative concepts using Plantsmith process simulator The evaluation presents possible improvements in the existing plants, and alternative concepts with their opportunities and pitfalls. The results show that a methodological approach can bring a wide understanding of the plant operations and simulation tool is useful for evaluating operational scenarios. Also, multiple practical aspects are presented concerning the investigation process.
  •  
40.
  • Bhadani, Kanishk, 1991, et al. (författare)
  • Simulation-Driven Development for Coarse Comminution Process - A Case Study of Geita Gold Mine, Tanzania using Plantsmith Process Simulator
  • 2021
  • Ingår i: Proceedings of the Design Society. - : Cambridge University Press (CUP). - 2732-527X. ; 1, s. 2681-2690
  • Konferensbidrag (refereegranskat)abstract
    • A comminution process is a material size reduction and separation process which is primarily used in the aggregates and the minerals processing industry. Knowledge related to equipment’s operation, raw material properties, operational strategies, control system, maintenance, etc. is needed to design a capable plant. New needs are arising from the industry for existing operational crushing plants such as investigation for improvements, upscaling, and downscaling of the capacity. The paper presents an application of simulation-driven development for a crushing plant in an existing gold processing plant. Due to the change in ore characteristics and the need for optimizing the cost of operation, it is required to investigate the opportunities for improvement and alternative options for downscaling the capacity of the plant. A systematic process for configuring, developing, and evaluating alternative concepts using a process simulation tool is presented. The results show the process of generating knowledge for alternative crushing plant operation settings and how the choices can be selected and eliminated using boundary conditions. The evaluation presents possible improvements and alternative concepts with their opportunities and pitfalls.
  •  
41.
  • Bhadani, Kanishk, 1991, et al. (författare)
  • State of the Art in Application of Optimization Theory in Minerals Processing
  • 2017
  • Ingår i: European Symposium on Comminution and Classification, Izmir, Turkey.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • There has been continuous development going over the past 40 years related to the creation of models and simulation techniques to predict the behaviour of equipment and processes in minerals processing. At the same time, application of optimization theory into such modelling and simulation schemes has been applied to generate knowledge to improved performances of the equipment and processes.Different optimization techniques have been applied to design and configure different equipment and processes, yet there are no well-established formulations to reproduce the results. The research is scattered and focused on the need and application of the specific equipment or process not utilizing the optimization’s full potential.The aim of this paper is to highlight the trends in development of optimization schemes in minerals processing. By understanding the state of the art in application of optimization theory into mineral processing will further pave the possibility to develop utility in this field. The paper presents two classification schemes: State of Development Stage and State of Application Area as a basis to classify research within optimization related to mineral processing. In order to make smart and strategic decisions in minerals processing operations, it is required to further develop optimization techniques into modelling and simulation schemes to extract the relevant information. The classification schemes can be useful in defining the future focus area for research and development.
  •  
42.
  • Bhadani, Kanishk, 1991, et al. (författare)
  • Trade-Off Curves for Performance Optimization in a Crushing Plant
  • 2023
  • Ingår i: Minerals. - 2075-163X. ; 13:10
  • Tidskriftsartikel (refereegranskat)abstract
    • Operational flexibility in an aggregate production process is required to adapt to changes in customer demands. Excessive demand for a particular product fraction can lead to operational alteration wherein re-crushing of the existing larger-sized product fraction is necessary. The choice of re-crushing existing product fractions results in feed condition changes to the crusher. One common approach to producing the desired product is by varying the operation settings of a crusher in a crushing plant. However, knowledge of differences in operational performance for changing feed conditions in the circuit is required. This potentially leads to a problem of performance optimization based on the desired target product, available feed material and capability of the crusher. The paper presents an application of a multi-objective optimization method to generate multiple operational settings for the dynamic change in the operation condition in a crushing plant. Controlled experimental survey data with varying feed conditions are used to calibrate the crusher model using an unconstrained optimization problem solved using a gradient-based algorithm (Quasi-Newton method). Trade-off curves between various performance indicators of the crushing plant using a dynamic simulation platform are generated using multi-objective optimization using a non-gradient-based algorithm (genetic algorithm). The results of the application can help the operators and plant managers to make proactive decisions to steer the operation of the crushing plant towards the desired needs of the operation.
  •  
43.
  • Davoodi, Ali, 1984, et al. (författare)
  • Application of the Discrete Element Method to Study the Effects of Stream Characteristics on Screening Performance
  • 2019
  • Ingår i: Minerals. - : MDPI AG. - 2075-163X. ; 9:12
  • Tidskriftsartikel (refereegranskat)abstract
    • Screening is a key operation in a crushing plant that ensures adequate product quality of aggregates in mineral processing. The screening process can be divided into the two sub-processes of stratification and passage. The stratification process is affected by the relative difference between various properties, such as particle shape, size distribution, and material density. The discrete element method (DEM) is a suitable method for analyzing the interactions between individual particles and between particles and a screen deck in a controlled environment. The main benefit of using the DEM for simulating the screening process is that this method enables the tracking of individual particles in the material flow, and all of the collisions between particles and between particles and boundaries. This paper presents how different particle densities and flowrates affect material stratification and, in turn, the screening performance. The results of this study show that higher density particles have a higher probability of passage because of their higher stratification rate, which increases the probability that a particle will contact the screen deck during the process.
  •  
44.
  • Davoodi, Ali, 1984, et al. (författare)
  • Investigating the effect of the feeding arrangement on screen media wear and screening efficiency by using DEM
  • 2021
  • Ingår i: Minerals Engineering. - 0892-6875. ; in press
  • Tidskriftsartikel (refereegranskat)abstract
    • The discrete element method (DEM) is an effective tool for studying particles and equipment interactions in comminution and classification processes. Comminution and classification process performances are dependent on the operational conditions of different units. For screens, the performance of the particle separation is affected by the wear on the screening media. This work aims to study how screening performance, along the deck, is affected by different feeding arrangements, and how it influences screen media wear. A series of DEM simulations were configured to different feeding arrangements and validated with data from a crushing plant. The simulation results and process data show how screen media wear patterns can appear in a different section of the screen and how significant their effect is on the screening performance along the deck.
  •  
45.
  • Davoodi, Ali, 1984, et al. (författare)
  • Validation of a DEM model of screening performance
  • 2021
  • Ingår i: Minerals Engineering. - 0892-6875. ; in press
  • Tidskriftsartikel (refereegranskat)abstract
    • The discrete element method (DEM) is particularly suited to modelling screening processes in the minerals processing industry, since the control and optimisation of screen processes are still limited due to a lack of their fundamental understanding and the number of different design variables and machine parameters that affect the processes. The advantage of using DEM for assessing screening performance is the possibility of visualising particle behaviour in three dimensions along with the screen media. This study shows how the DEM can be used to analyse different screen machine parameters and material properties for further development. The effects of operational conditions and geometry on the screen performance are studied by a series of DEM simulations and experimental tests using a special laboratory screen. The simulations of screen performance are implemented over a variety of structural parameters, including screen width, aperture size, inclination angle and motion type. The results are analysed by distributions of percentage passing and other flow information, such as particle volume and velocities along the screen deck and the particle size distribution. The simulation results are useful for the development of a better understanding of the process and the control of the screen to create a predictive simulation model that can be used in dynamic process simulations of crushing and screening plants.
  •  
46.
  • Erdem, Ilker, 1987, et al. (författare)
  • Feedforward control for oscillatory signal tracking using Hilbert transform
  • 2019
  • Ingår i: European Journal of Control. - : Elsevier BV. - 0947-3580. ; 50, s. 41-50
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper presents feedforward control for oscillatory signal tracking using Hilbert transform. The proposed controller utilizes Hilbert transform and analysis techniques to determine the signal's amplitude, frequency, and phase. By using the frequency response of the linear time-invariant process model, an amplified and phase-shifted feedforward signal is reconstructed. The proposed controller also analyzes the system response to determine the differences from the model to modify the feedforward signal. Simulation experiments with multicomponent stationary, amplitude-, and frequency-modulated signals are also conducted. The results show that using an amplified and phase-shifted signal determined by Hilbert analysis can enable an effective tracking performance.
  •  
47.
  • Erdem, Ilker, 1987, et al. (författare)
  • Workpiece force and position control for active and flexible fixtures in assembly
  • 2021
  • Ingår i: International Journal of Advanced Manufacturing Technology. - : Springer Science and Business Media LLC. - 0268-3768 .- 1433-3015. ; 112:1-2, s. 333-346
  • Tidskriftsartikel (refereegranskat)abstract
    • With strengthening focus on digitalization and flexibility, active and flexible fixtures can provide the right tools for manufacturing systems. However, fixturing solutions are often too individualized for processes and need a universal approach. Firstly, a system formulation of multiple workpieces interacting with each other is presented. Secondly, strategies for direct and indirect force control along with their characteristics have been developed. The stability of assembly of force-controlled components has been analyzed, and certain key characteristics have been presented. The position control under different signal types, including oscillatory, have been discussed. Finally, a set of experiments have been conducted for performance evaluation.
  •  
48.
  • Evertsson, Magnus, 1967, et al. (författare)
  • Versatile crusher control and cloud computing process monitoring
  • 2019
  • Ingår i: Book of Extended Abstracts, 16th European Symposium on Comminution and Classification. ; , s. 103-104
  • Konferensbidrag (refereegranskat)abstract
    • The main task of a crusher control system is to keep production on a desired level and to protect the crusher from overload and fatigue failure. A stable production can be achieved through control of the crusher’s closed side setting (CSS), which implies compensation of the wear of the crusher liners. A further objective is to provide with the possibility to optimize operational performance and utilization. For an efficient system the sampling rate needs to be sufficiently high and the control and optimization algorithms need to be robust. In addition and equally important, configuration of the electrical cabinet and wiring must be able to withstand the harsh environment. Modelling and simulation of cone crushers have been on-going at Chalmers University of Technology during the last 25 years. Over time the research has expanded to include several different aspects of cone crusher operation, design optimisation, real-time control and product yield optimization. As a consequence a strong need for dedicated control possibilities of cone crushers have risen. The requirement for precise control led to the development of a new system for crusher control which was named Crusher Control Unit or CCU. The system have been further developed by Roctim to provide an independent, modular and flexible development platform for different crusher types. A unique feature is that the CCU can be retrofitted to both Hydrocone type of cone crushers as well as to Symons type independent of brand or age of the crusher.
  •  
49.
  • Grunditz, Simon, 1990, et al. (författare)
  • Fit-for-Purpose VSI Modelling Framework for Process Simulation
  • 2021
  • Ingår i: Minerals. - : MDPI AG. - 2075-163X. ; 11:1, s. 1-12
  • Tidskriftsartikel (refereegranskat)abstract
    • The worldwide shortage of natural sand has created a need for improved methods to create a replacement product. The use of vertical shaft impact (VSI) crushers is one possible solution, since VSI crushers can create particles with a good aspect ratio and smooth surfaces for use in different applications such as in construction. To evaluate the impact a VSI crusher has on the process performance, a more fit-for-purpose model is needed for process simulations. This paper aims to present a modelling framework to improve particle breakage prediction in VSI crushers. The model is based on the theory of energy-based breakage behavior. Particle collision energy data are extracted from discrete element method (DEM) simulations with particle velocities, i.e., rotor speed, as the input. A selection–breakage approach is then used to create the particle size distribution (PSD). For each site, the model is trained with two datasets for the PSDs at different VSI rotor tip speeds. This allows the model to predict the product output for different rotor tip speeds beyond the experimental configurations. A dataset from 24 different sites in Sweden is used for training and validating the model to showcase the robustness of the model. The model presented in this paper has a low barrier for implementation suitable for trying different speeds at existing sites and can be used as a replacement to a manual testing approach.
  •  
50.
  • Gröndahl, Albin, 1994, et al. (författare)
  • Diagnostics of cone crusher feed segregation using power draw measurements
  • 2018
  • Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875. ; 127, s. 15-21
  • Tidskriftsartikel (refereegranskat)abstract
    • In comminution processes, the equipment normally operates at non-optimal conditions and due to poor access to crushers and deficient monitoring of them, this information is not acquired. Cone crushers have a crushing chamber that is revolved around its centre axis and crushing does not occur all at once but in a circular motion. This property gives rise to a potential non-optimal crushing in the form of power draw fluctuations due to the variance in feed across the crushing chamber with respect to e.g. mass flow, particle size distribution and other material properties. Studies have shown that a high rate of the power draw measurement provides the ability to expose a feeding miss-alignment. This paper shows how changes in the operation of the crusher, due to differences in feed material properties as a segregation, can be diagnosed and determined for future comminution process improvements.
  •  
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