| 1. |
- 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.
|
|
| 2. |
- 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.
|
|
| 3. |
- 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.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Bengtsson, Magnus, 1973, et al.
(författare)
-
Cost And Performance Optimization Of A Tertiary Crushing Stage
- 2015
-
Ingår i: ESCC 2015 Conference. - Göteborg : Chalmers University of Technology. - 9789188041012
-
Konferensbidrag (refereegranskat)abstract
- There is increasing demand to optimise performance and profit of crushing plants. Research in this area has resulted in the development of numerous optimisation tools, and resent research has shown that the quality aspects of production have great influence on the optimisation results. The quality, cost, profit and capacity of a product is influenced by several parameters, and in order to control all of these parameters it is necessary to use some sort of optimisation software. In this paper, a novel approach use the parameters cost, profit, capacity and quality in order to perform a multi objective optimization of a crushing plant is presented. As an example a tertiary crushing stage consistent of a cone crusher and a vertical shaft impact crusher (VSI) is used as base for the designed objective function. The process has a given set of constraints that represents the conditions normal in these type of crushing 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. The next step in the optimization shows how a strategy for relaxing constraint can increase overall productivity and still reach certain product properties. The conclusions made in this work are that multi objective optimization is essential when optimizing crushing plant production against multiple objectives. Relaxation of constraints can increase the overall performance of the crushing plant.
|
|
| 7. |
- Bengtsson, Magnus, 1973, et al.
(författare)
-
Framework for material modelling in a processing plant
- 2015
-
Ingår i: Computational Modelling ‘15.
-
Konferensbidrag (refereegranskat)abstract
- Material modelling within a crushing plant is closely dependent on both manual and automatic operations as well as a close follow up on the utilization of the plant performance from a management perspective. The desire to fully be able to utilize the crushing plant with respect e.g. to material handling is limited due to the lack of possibility to fully observe actions within the process. There are large quantities of data that can be monitored in the crushing plant SCADA system. However the data collected are governed by the quantity of actual sensors in the process. The aim with this paper is to propose a method for how-to pre-process the automatically gathered SCADA data in order to fill up dynamic models for process simulations. There is a fundamental need to increase the resolution of how the crushing plant behaves. This will be structured as a framework for analysing and suggesting model improvements that will increase the utilization and decrease both manual operations and give better performance when controlling the process.
|
|
| 8. |
- Bengtsson, Magnus, et al.
(författare)
-
Improving yield and shape in a crushing plant
- 2009
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 22:7-8, s. 618-624
-
Tidskriftsartikel (refereegranskat)abstract
- There is increasing demand to optimise yield and increase capacity of crushing plants. Research in this area has resulted in the development of numerous optimisation tools, and resent research has shown that the economic aspects of production have great influence on the optimisation results. The profitability of a product is influenced by several parameters, and control of all these parameters is necessary to use some sort of optimisation software. In this paper, we present a case study of a typical crushing plant, with the goal of reducing the number of crusher while keeping the plant capacity and quality. By reducing the number of crusher the plant will need less maintenance which will decrease the operating costs. The article presents a method to combine crushing plant simulation and optimisation with quality and economic considerations in order to successfully study alternative configurations of the plant.
|
|
| 9. |
- Bengtsson, Magnus, 1973, et al.
(författare)
-
Improving Yield and Shape in a Crushing Plant
- 2009
-
Ingår i: Proceedings of 12th European Symposium on Comminution and Classification (ESCC2009).
-
Konferensbidrag (refereegranskat)abstract
- There is increasing demand to optimise yield and increase capacity of crushing plants. Research in this area has resulted in the development of numerous optimisation tools, and resent research has shown that the quality aspects of production have great influence on the optimisation results. The quality and capacity of a product is influenced by several parameters, and in order to control all these parameters it is necessary to use some sort of optimisation software. In this paper, a novel approach to analyse parameters influence on product capacity and quality is presented. As an example a cone crusher and a vertical shaft impact crusher (VSI) is simulated in a tertiary stage. The simulation shows how capacity and product quality for a range of products will be affected when a parameter is changed. The paper also shows how wear will affect product capacity and quality.
|
|
| 10. |
- Bengtsson, Magnus, 1973, et al.
(författare)
-
Influence of throw and compression ratio on particle shape - A full scale investigation and laboratory tests
- 2010
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 23:7, s. 549-557
-
Tidskriftsartikel (refereegranskat)abstract
- The machine parameters of throw and eccentric speed affect the particle shape. Their influence on particle shape is however not fully investigated. Preliminary tests on a full-scale crusher had shown certain trends in regard to the flakiness of the product (Fig. 1). These effects were investigated in detail by means of a series of piston-and-die tests, followed by modelling of the laboratory data. An empirical model of a crusher was developed which links the product size distribution and the shape of the particles to operating parameters. The simulator produced trends which were similar to the full-scale data. The throw and eccentric speed affects the utilised compression acting on the rock/rock-bed. This paper presents a method suitable for characterizing the compressive breakage behaviour of rock materials during form conditioned compression. In this method, size reduction is primarily related to geometric compression. The method provides a complete description of the breakage characteristics of the tested rock material when compressive crushing is employed. The results can be used for modelling and simulation purposes in the design of crushing equipment or crushing plants. A novel approach to optimise form conditioned crushing in order to achieve an acceptable particle size and shape is presented. The paper concludes that inter-particle breakage in combination with high compression ratio is beneficial for the particle shape. The full scale tests support this since an increase in throw improves particle shape for particles subjected to inter-particle breakage. © 2009 Elsevier Ltd. All rights reserved.
|
|
| 11. |
- Bengtsson, Magnus, et al.
(författare)
-
Measuring characteristics of aggregate material from vertical shaft impact crushers
- 2006
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 19:15, s. 1479-1486
-
Tidskriftsartikel (refereegranskat)abstract
- Natural gravel has traditionally been the main choice of material for Swedish concrete manufacturers. However, due to the fact that natural gravel also acts as a fresh water filter, the deposits are limited. The obvious question is how to compare machine made and natural gravel in terms of particle shape, rheology and other material characteristics. This paper will present some methods and results that demonstrate performance of different machine made rock materials. Particle shape characteristics were assessed from flow measurements in a standard cone. The vertical shaft impact crusher (VSI) produces gravel that is a good alternative to natural gravel. The quality of the material and the particle shape seem to meet concrete producers’ demands.
|
|
| 12. |
- 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.
|
|
| 13. |
- Bengtsson, Magnus, 1973, et al.
(författare)
-
Modelling of output and power consumption in vertical shaft impact crushers
- 2008
-
Ingår i: International Journal of Mineral Processing. - : Elsevier BV. - 0301-7516 .- 1879-3525. ; 88:1-2, s. 18-23
-
Tidskriftsartikel (refereegranskat)abstract
- The vertical shaft impact (VSI) crusher is a commonly-used machine in aggregate production. A comprehensive understanding of the physical phenomena that influence the power consumption and the particle output of the device are essential to enable development of protocols that minimize energy consumption during rock crushing.While natural gravel has traditionally been the main choice of material for Swedish concrete manufacturers, the number of deposits is limited due to its role as a fresh water filter. It is therefore essential to achieve a product size distribution of aggregate that is on the same order as that of natural gravel to enable its use in concrete production.This work aims to present a model that predicts capacity, power and particle size distribution in a VSI crusher.
|
|
| 14. |
- Bengtsson, Magnus, 1973, et al.
(författare)
-
Size and shape simulation in a tertiary crushing stage, a multi objective perspective
- 2015
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 77, s. 72-77
-
Tidskriftsartikel (refereegranskat)abstract
- There is increasing demand to optimise yield and increase capacity of crushing plants. Research in this area has resulted in the development of numerous optimisation tools, and recent research has shown that the quality aspects of production have great influence on the optimisation results. The quality and capacity of a product is influenced by several parameters, and in order to control all of these parameters it is necessary to use some sort of optimisation software.In this paper, a novel approach to analyse the parameters product capacity and quality is presented. As an example a cone crusher and a vertical shaft impact crusher (VSI) is simulated in a tertiary stage. The simulation shows how capacity and product quality for a range of products will be affected when a parameter is changed. The paper also shows how wear will affect product capacity and quality.
|
|
| 15. |
- 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.
|
|
| 16. |
- 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.
|
|
| 17. |
- Bhadani, Kanishk, 1991, et al.
(författare)
-
Application of Structural Optimization for an Early Stage Product Development
- 2017
-
Ingår i: NAFEMS World Congress 2017, A World of Engineering Simulation, Stockholm, Sweden. - 9781910643372 ; , s. 13-
-
Konferensbidrag (refereegranskat)abstract
- In today’s automotive industry there is a growing demand for more fuel efficient vehicles and reduced development times. These trends are driven by stricter environmental regulations, a growing environmental awareness, and increasing technological development and competitiveness. Finding an optimized and balanced component that fulfils the requirements in an early phase of the product development is a prerequisite for enabling more competitive lead times, costs, weights and minimizing the risk for late design changes. The aim with this paper is to show a process capturing CAE driven development for an early stage development of components in a complex system. The process utilizes structural optimization techniques to generate knowledge, optimize and balance packaging volumes of adjacent components in complex systems. The paper also highlight the organizational challenges and technical challenges involving the use of structural optimization for realizing the process completely. The paper will illustrate the simultaneous use of topology and shape optimization to generate knowledge for the optimized design volume for multiple adjacent components linked together. The linking of the multiple component is carried out using morphing technique and the design space between the multiple components is dynamic in nature during simulation. The mesh in one component is allowed to change according to the mesh of the other component during the simulation. The result from the simultaneous topology and shape optimization simulation generates the knowledge if it is feasible to change design volume to meet the weight and performance targets. The process also indicates how much performance increase is possible if the design volume is allowed to change and thus generating a trade-off between the components performance.The new process has a potential to be extended to other conflicting scenarios in adjacent components which exists in early stages of development process especially, cases involving conflicting structural requirements in various industries.
|
|
| 18. |
- 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.
|
|
| 19. |
- 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.
|
|
| 20. |
- Bhadani, Kanishk, 1991, et al.
(författare)
-
Student Perspectives on Video-Based Learning in CDIO-Based Project Courses
- 2017
-
Ingår i: The 13th International CDIO Conference Proceedings, Calgary, Canada. - 1796-9964. - 9780889533998 ; , s. 689-704
-
Konferensbidrag (refereegranskat)abstract
- This paper aims at demonstrating the applicability of video learning in CDIO based project courses and at evaluating to what extent it benefits students. The courses are Machine Elements (PPU210), Product Planning - Needs and Opportunities (PPU085) and Engineering Design and Optimization (PPU190) in the Mechanical Engineering programme at Chalmers University of Technology. The research was carried out by first creating a set of videos for selected topics in three courses. In total, 22 videos were created including topics such as “Benchmarking”, “SWOT”, and “Prototype lab equipment instructions”. The learning outcomes of the video lectures were mapped to the CDIO syllabus. A blended learning environment was developed, i.e. the videos were utilised as additional support alongside existing learning activities. The videos were then used in the courses and the students’ feedbacks collected through a dedicated questionnaire, the regular course evaluation survey, and in student-teacher group meetings during and after the courses. The collected data was analysed to produce inferences about the applicability and utility of the video lectures. The resulting analysis shows the students’ preferences regarding the evaluated video lectures and instructions. The students find videos more appealing compared to traditional lectures. One of the main benefits highlighted is the possibility of watching the videos in parallel to the design-build-test project execution rather having the classroom lecture only. This helps in reinforcing concepts, and results in less dependency on supervisors during the project execution. Videos proved to be suitable for creating a blended learning environment and improved the perceived learning experience for the students. In order to maximize student satisfaction and interaction with the videos, the videos should be short and closely aligned to the other learning activities. The paper also suggests future improvements to be carried out for video-based learning in the courses, and proposes an easy adaptable way for teachers to develop video material.
|
|
| 21. |
- Davoodi, Ali, 1984, et al.
(författare)
-
Analysis of Screening Performance using Discrete Element Modeling
- 2017
-
Ingår i: Proceedings of the Conference in Minerals Engineering. ; 2017
-
Konferensbidrag (refereegranskat)abstract
- Screening is an important process in size classification of granular materials. It is a complex process due to the collision between particles and also a number of different operational parameters that effect the screening process. The aim of this paper is to evaluate screening performance in one of the LKAB crushing platforms. In this work an industrial vibration screen has been simulated by using Discrete Element Method (DEM). The simulations were validated with data from experiments and the screening performance has been analyzed by changing the parameters such as feeding rate. The result shows that DEM simulation is an effective tool for understanding the process of screening and because of the contact model between individual particles and particles and geometries the result is comparable with real process. It is shown that by increasing the feeding rate to 100 ton/h the screening efficiency can be improved by 20 percent.
|
|
| 22. |
- Davoodi, Ali, 1984, et al.
(författare)
-
DEM Modelling and Simulation of Banana Screen Classification Efficiency
- 2015
-
Ingår i: Minerals Engineering. - 0892-6875.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Banana screens are popular and frequently used in minerals processing. The screens are characterized by a high separation capacity and low maintenance need. The operation of screening usually takes place after crushing operation. The banana screens have multiple panels with variable slope which enables the feed material to flow rapidly resulting in a high screening rate. The difference between banana screens and other screens is that in banana screens the screen cut size varies with the changing slope of the decks. There are a number of factors affecting the screening operation; the deck panel slope progression, screen deck material, aperture shape, vibrational motion, open area, thickness of deck, feed rate and material properties.The aim of this paper is to simulate the screening performance by using the Discrete Element Method (DEM) and to analyse different motions that affect screening operation efficiency. Three decks with different slopes have been used and two different motions, linear and elliptical, have been evaluated at one feed rate. Figure 1 shows the overview of DEM simulation of screening process. Design of Experiment (DoE) has been used to evaluate the factors that control the value of parameters. The results show that the classification efficiency can be evaluated by conventional comparison between the feed particle size distribution and each of the product streams. The resolution of the model also enables the calculation of a critical efficiency criteria position along the screen deck. This position can be used to define a screening robustness factor. The passage probability and stratification behaviour can also be evaluated.
|
|
| 23. |
- Davoodi, Ali, 1984, et al.
(författare)
-
DEM simulation of banana screen performance
- 2015
-
Ingår i: Proceedings, ;Minerals Engineerings Conference Physical Separation 2015 June 11-12...
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Banana screening is an important size classification component. The screens are characterized by a high capacity for separation. The operation of screening usually takes place after crushing operation. The shape of the banana screens causes the feed material to flow rapidly and the result will be faster screening rate. The difference between banana screens and other screens is that in banana screens the screen cut size varies with the changing slope of the decks. There are number of factors that affect screening operation like inclination of discharge, open area, thickness of deck and feed rate.The aim of this paper is to simulate the screener deck with the help of DEM Simulation and to analyze different parameters that affect screener operation efficiency and optimizing the screener so that it has the best performance during the wear life of the screen media. The one deck banana screen are simulated, the result show when the value of deck thickness and deck slope increase the probability of particles passage through the apertures will be decrease.
|
|
| 24. |
- Davoodi, Ali, 1984, et al.
(författare)
-
Effects of screen decks' aperture shapes and materials on screening efficiency
- 2019
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 139
-
Tidskriftsartikel (refereegranskat)abstract
- Screening is a key unit operation for the large-scale separation of materials. There are certain different machine parameters and variables that affect the process of screening. The Discrete Element Method (DEM) is a suitable method to analyze parameters and variables. The main benefit of using the DEM for simulating the screening process is that, as a contact model, it provides the possibility of tracking each particle in the material flow and all collisions between particles and between particles and boundaries. There are different types of materials used for screening media, such as rubber and polyurethane, which are used in modular systems as a panel, and such as steel, which are used as a wire in the mesh. This paper presents how different materials used in screen decks affect the screening process. The materials' strength and elasticity have been examined in order to study how the aperture will change in different materials and how different shapes of the aperture and material of screening media affect the screening performance by analyzing the effect on material flow.
|
|
| 25. |
- Davoodi, Ali, 1984, et al.
(författare)
-
The effect of different aperture shape and material of screen deck on screening efficiency
- 2018
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Screening is a key unit operation for the large-scale separation of materials. There are a number of different machine parameters and variables which affect the process of screening. The Discrete Element Method (DEM) is a suitable method to analyze all parameters and variables. The main benefit of using DEM for simulating the screening process is that as a particle contact model it gives the possibility to track each particle in the flow and all collisions between particles and between particles and boundaries. There are a number of different materials commonly used for screen media such as rubber and polyurethane which are used in modular systems as a panel and steel is usually used as steel wire mesh but sheet metal can also be used. This paper presents how different materials used in screen decks affect the screening process. The strength and elasticity has been examined in order to study how the aperture will change with different materials and also how different shapes of the aperture and the material of screen media affect the screening performance by analyzing different material flow.
|
|
| 26. |
- Evertsson, Magnus, 1967, et al.
(författare)
-
Control Systems for Improvement of Cone Crusher Production Yield and Fatigue Life
- 2015
-
Ingår i: Conference in Minerals Engineering 2015.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Control systems for cone and gyratory crushers were first introduced during the early 60ths. The common opinion is that if these systems are able to compensate for the wear of the crushing liners the production yield can be increased with 20-25%. Over the years these types of systems have been widely used but the theory behind the principles have not been thoroughly scientifically scrutinized and presented. Of special interest is the capability to protect the crushers from long term overloading commonly defined as fatigue.
|
|
| 27. |
- Evertsson, Magnus, 1967, et al.
(författare)
-
Control systems for improvement of cone crusher yield and operation
- 2014
-
Ingår i: Proceedings of Comminution '14.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Gyratory and cone crushers are regaining interest and are becoming more frequently used in order to create more energy efficient comminution circuits. A typical example is found in coarse comminution circuits were HPGRs are used as a first milling stage. In this case the preparation of a suitable feed with a well-defined width of the particle size distribution and a controlled top size are of high importance. In turn, this emphasizes the importance of a stable and controlled operation of the preceding crushing stages. Control systems for cone and gyratory crushers were first introduced during the early 60ths. The common opinion is that if these systems are able to compensate for the wear of the crushing liners the production yield can be increased with 20-25%. Over the years these types of systems have been widely used but the theory behind the principles have not been thoroughly scientifically scrutinized and presented. Of special interest is the capability to protect the crushers from long term overloading commonly defined as fatigue.With developments in electronics and plant control the crusher control systems have become more refined over the years. Though, there are sometimes conflicting interests in the control strategies between process requirements and crusher protection. In the paper an overview of the challenges, opportunities and existing control systems for cone and gyratory crushers is presented. A requirement specification for a system that is possible to fully integrate into modern plant control systems is outlined.
|
|
| 28. |
- Evertsson, Magnus, 1967, et al.
(författare)
-
Monitoring and validation of life time prediction of cone crusher with respect to loading and feeding conditions
- 2016
-
Ingår i: Comminution 16. - 9781510826670 ; 904 (1 Vol)
-
Konferensbidrag (refereegranskat)abstract
- The interest and need for compressive crushing in gyratory, cone and HPGR crushers are increasing since ores become more competent and more difficult to break. Compressive crushing is energy efficient as a consequence of the crushing principle and the imposed stress-state. The stress variations can be described by stress amplitudes and it is a known fact that many different materials, components and machines suffer from cyclic loading which shortens the service lifetime. This phenomena is explained by density variations of the particle beds in the equipment which in turn originates from particle segregation and feeding alignment. The phenomena is often called fatigue and the consequence is premature breakdowns and a relatively shorter lifetime than expected. In this paper, a previously developed theory for lifetime assessment of cone crushers will be used as a foundation for evaluation of full-scale operating cone crushers in minerals processing plants. Lifetime is calculated as a consequence of the load spectrum. The data shows that improper feeding conditions will substantially decrease the lifetime of the crusher equipment leading to excessive operating costs. An adequate control system should be able to recognise the hazardous lifetime decreasing overloads and to warn the operator. There are sometimes conflicting interests in the control strategies between production yield (process requirements) and crusher protection.
|
|
| 29. |
|
|
| 30. |
- Grunditz, Simon, 1990, et al.
(författare)
-
Prediction of Collision Energy in the VSI Crusher
- 2015
-
Ingår i: Proceedings; European Symposium on Comminution and Classification 2015 September 7-10.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- VSI crushers are established comminution machines often used for size reduction and to improve the sphericity of rock particles. Data collection and experimental observation inside VSI crushers remains difficult, leading to lack of understanding of the full extent of the particle dynamics inside a VSI crusher. The aim of this paper is to attempt to characterize the probability of collision of particles in relation to their distance from the rotor. By comparing the number of collisions at a given location with the overall amount of collisions, the probability of a collision event related to the distance a particle has travelled from the rotor can be estimated. The result is an increased understanding of VSI crushers and the particle collision behaviour inside of a VSI crushing chamber.
|
|
| 31. |
- Grunditz, Simon, 1990, et al.
(författare)
-
The Effect of Rotor Tip Speed of a Vertical Shaft Impactor on the Collision Energy Spectrum
- 2015
-
Ingår i: Proceedings;Minerals Engineering Conference Computational Modelling 2015 June 10-11.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The increasing restrictions on natural aggregates have led to a demand for effective production of artificial sand and gravel. VSI crushers are established comminution machines often used in order to improve the sphericity of particles. Due to the difficulty in data collection, the full extent of the particle dynamics inside a VSI crusher has remained unexplored.The aim of this paper is to use DEM simulations to model a full-scale crusher, generate a realistic material flow and make a number of crusher tests with different rotor tip speeds. Each particle’s collision energy compared to its size will provide a spectrum which can be related to the probability of breakage. This will show how increasing rotational speed affects collisions and the impact energy of particles inside the crusher. The result is an increased understanding that can allow optimization and modeling of VSI crushers with higher accuracy.
|
|
| 32. |
- Guldris, Lorena, 1983, et al.
(författare)
-
'Mineralogical characterization, reduction and liberation analysis of tungsten ore
- 2016
-
Ingår i: Emerging Trends in Minerals Engineeing.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Due to the raising global demand for rare earth minerals there is an increased need for development of more efficient extraction processes of such materials. Comminution models commonly predict size reduction with the focus on a single component, but few models integrate the mineral composition. This paper focuses on defining a multi component model, combining the size reduction and the mineral liberation. In this study, compressive breakage and liberation analysis experiments were conducted on a Tantalum ore. The work is divided into two stages, firstly the methodology of fitting measured data into a size reduction model, and secondly the multi component modelling where the liberation results are integrated into the size reduction model. Results from the work show that in order to address multi component modelling it is necessary to focus on dominating factors such as dominating quantities of different minerals. It was also seen that the model can be used for determining the choice of compression ratio in crushing for optimizing liberation.
|
|
| 33. |
- Guldris, Lorena, 1983, et al.
(författare)
-
Modelling Reduction and Liberation for Rare Earth Minerals Applications
- 2016
-
Ingår i: MEI 10th International Comminution Symposium (Comminution '16).
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Due to the raising global demand for rare earth minerals there is an increased need for development of more efficient extraction processes of such materials. Comminution models commonly predict size reduction with the focus on a single component, but few models integrate the mineral composition. This paper focuses on defining a multi component model, combining the size reduction and the mineral liberation.In this study, compressive breakage and liberation analysis experiments were conducted on a Tantalum ore. The work is divided into two stages, firstly the methodology of fitting measured data into a size reduction model, and secondly the multi component modelling where the liberation results are integrated into the size reduction model.Results from the work show that in order to address multi component modelling it is necessary to focus on dominating factors such as dominating quantities of different minerals. It was also seen that the model can be used for determining the choice of compression ratio in crushing for optimizing liberation.
|
|
| 34. |
- Guldris, Lorena, 1983, et al.
(författare)
-
Reduction and fracture analysis of a tungsten ore and its use for fundamental liberation modelling
- 2016
-
Ingår i: Procemin 2016. 12th International Mineral Processing Conference.
-
Konferensbidrag (refereegranskat)abstract
- Nowadays there are numerous tungsten applications and uses, due to this the global demand for tungsten has increased the extraction and production of this rare earth mineral. The liberation of tungsten is achieved by using comminution equipment, e.g. crushers, there is a lack of knowledge how tungsten is liberated by means of compressive breakage. Even though it is possible to use find comminution models for explaining the size reduction, there is also need to implement a mineral liberation model into theses comminution models. This paper will focus on a fundamental model that combine and integrate the size reduction with the mineral liberation in early stages of the breakage process.This work focuses on analysing the liberation characteristics that occur by means of interparticle breakage. The work includes two parts, firstly the integration of the measured data into a size reduction model, and secondly a reflexion and understanding of the liberation and fracture mechanism during the breakage.Results from the work show that in order to address multi component modelling it is necessary to focus on controlling factors such as dominating quantities of different minerals, breakage mechanism in different bounded minerals and how this is connected with the liberation of them. It also was observed that the model could be used for determining the choice of the compression ratio in crushing for optimising liberation.
|
|
| 35. |
- Guldris Leon, Lorena, 1983, et al.
(författare)
-
Analysis of the concentration in rare metal ores during compression crushing
- 2018
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 120, s. 7-18
-
Tidskriftsartikel (refereegranskat)abstract
- Given the increasing global demand for rare metals, there is a need for the development of fundamental predictive models to improve extraction processes. Comminution models commonly predict particle size reduction based on the compressive breakage behaviour; however, few of them include mineral concentration or mineral liberation at a coarse scale. This paper focuses on developing a model to predict the mineral concentration of rare metals as a function of the particle size distribution after a cycle of the compression crushing process. In this study, compressive breakage and geochemical analysis experiments were conducted on four different rare metal ores of tantalum and tungsten. The work is divided into two stages: the methodology of modelling particle size and modelling concentration by selecting a bimodal Weibull distribution for calibration. A novel model for simulating the concentration of rare metals as a function of the compression ratio is presented.
|
|
| 36. |
- Johansson, Marcus, 1992, et al.
(författare)
-
A fundamental model of an industrial-scale jaw crusher
- 2017
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 105, s. 69-78
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, an analytical perspective is used to develop a fundamental model of a jaw crusher. Previously, jaw crushers were modelled in regard to certain aspects, for example, energy consumption (Legendre and Zevenhoven, 2014) or kinematics (Oduori et al., 2015). Approaches to date have been mainly property specific. In this work a physical modelling approach has been used to derive the modules, which are based on established facts of comminution machines, from the literature. A modelling methodology mainly inspired by Evertsson has been applied (Evertsson, 2000). The modules are divided into kinematics, flow, breakage, capacity, pressure and power. Each module has been derived and tested decoupled from the other modules to provide increased transparency of the module and its behaviour. The results of the modelling are presented for a baseline case of one industrial-scale jaw crusher and compared to manufacturer data. Future work will include validation and DEM simulations.
|
|
| 37. |
- Quist, Johannes, 1985, et al.
(författare)
-
CDIO Based Engineering Design and Optimization Course
- 2017
-
Ingår i: Proceedings of 2017 International CDIO Conference, Calgary, Canada. - 1796-9964. - 9780889533998 ; , s. 298-314
-
Konferensbidrag (refereegranskat)abstract
- In order to design competitive products that meet today’s challenges, future engineers need knowledge and experience in applying and integrating optimization theory in the engineering design process. The Chalmers course Engineering Design and Optimization addresses this need and was developed and first offered in the fall semester of 2013. This paper provides a detailed account of the course development experiences, teaching methods and course evaluations using CDIO Standards. It also includes a discussion of the learning objectives, required resources, instructional processes and student assessments. The course is analyzed to see to what extent the course aim is satisfied and highlight areas of improvement. Three projects are carried out in groups of two students. The projects are a cantilever design-build-test exercise, a redesign project that involves material selection, and a multi disciplinary design project of an engine component using multi-physics software. The assignments are assessed with respect to both engineering criteria as well as reporting and communication. The course is believed to be novel in the way optimization theory and tools are taught as an integrated learning experience with engineering design and physical prototyping. The course has had a great impact on the students’ choice of master’s thesis project. The number of optimization-focused master thesis projects has increased from two or three to around 15 annually. Several of these projects are multidisciplinary and joint projects between departments of Applied Mechanics and Product & Production Development. The course has also initiated a valuable partnership with industry on optimization that now has grown to a network with 20 industrial and academic members.
|
|
| 38. |
- 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.
|
|
| 39. |
- 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). - 1474-6670. - 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.
|
|
| 40. |
- 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.
|
|
| 41. |
- 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.
|
|
| 42. |
- 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.
|
|
| 43. |
- 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.
|
|
| 44. |
|
|
| 45. |
- 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.
|
|
| 46. |
- 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.
|
|
| 47. |
- 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.
|
|
| 48. |
- 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.
|
|
| 49. |
- 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.
|
|
| 50. |
- 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.
|
|
