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  • 1.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Kvarnström, Björn
    Tracing granular products using RFID2010Konferansepaper (Annet vitenskapelig)
  • 2.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Kvarnström, Björn
    Tracking and tracing products in continuous processes2011Inngår i: International Congress on Productivity, Quality, Reliability, Optimization and Modelling: ICPQROM 2011, Indian Statistical Institute , 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Traceability is important for quality control and process improvements, but it is often difficult to track or trace products in continuous process production, since products and product lots are difficult to separate. In the past, engineers have had to rely on coarse calculations for tracing products, but new possibilities emerge as new technology and models are being used. In this paper, we present experiences from applying chemical and RFID tracers to achieve traceability in continuous flows, with examples taken from the minerals processing sector.

  • 3. Kvarnström, Björn
    Developing distribution chain traceability in continuous processes: experiments in the iron ore pellets industry2007Inngår i: Proceedings from the 10th QMOD Conference: Our Dreams of Excellence, Lunds University, Campus Helsingborg , 2007Konferansepaper (Fagfellevurdert)
  • 4.
    Kvarnström, Björn
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Traceability in continuous processes: applied to ore refinement processes2010Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Introduction and purpose: Traceability is central for the identification of the root cause(s) behind a product deviation and thus to achieve a product and process quality that is both high and even. Continuous processes contain several characteristics complicating traceability which are not usually discussed in the scientific literature. The overall purpose of this thesis is to provide a theoretical framework for traceability and to test and develop methods for traceability in continuous processes. Design/methodology/approach: A literature review and interviews with engineers in continuous processes were performed in order to identify existing traceability theories and applications as well as characteristics complicating traceability in continuous processes. In addition, experiments evaluating traceability applications in three continuous processes were conducted at the Swedish iron ore refinement company Loussavaara Kiirunavaara AB (LKAB). Radio Frequency Identification (RFID), chemical tracer, and ideal flow simulations were, for example, used within the studied applications.Findings: A theoretical framework for traceability in continuous processes is outlined based on existing scientific literature. Several traceability methods suitable for continuous processes are described and illustrated within the framework. Furthermore, the complicating characteristics in continuous processes that each method may deal with are described. This thesis also presents and illustrates how traceability may be achieved in three continuous processes operating within ore refinement industries.Research limitations/implications: The presented research gives an insight into traceability theory and more specifically into traceability problems in continuous processes. However, the empirical results from the experiments are based on three specific processes, and research in other processes should be performed to validate the results.Practical implications: The presented results illustrate how to increase the ability to trace, track, and predict the product location in processes where traceability previously has been difficult.Originality/value: Prior research has primarily focused on discontinuous processes. By contrast, this thesis presents traceability from a continuous process perspective as well as the design and development of traceability applications for three of these processes.

  • 5.
    Kvarnström, Björn
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Traceability methods for continuous processes2008Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The subject of this thesis is traceability in continuous processes, i.e. the ability to trace products or batches through a certain process. Examples of the benefits from traceability are that it minimises the extent to which products are affected by product recalls and assures lot uniformity in production. The traceability in part production is often high, since various kinds of identification markers can be attached to a product or batch and followed. Further, the literature in the traceability field is dominated by descriptions of traceability issues in parts production. However, creating traceability in continuous processes implies vast challenges: process flows can be parallel, serial and reflux; sub processes can be continuous as well as batch-wise. These challenges are not commonly addressed in the research literature about traceability. Continuous processes are commonly found in process industries such as the mining, dairy and food, paper, and steel industries. The purpose of this thesis is to explore and describe how traceability can be improved in continuous processes. A research study consisting of a case study was designed and performed to fulfil the purpose. The results from the study are described in four papers. In Paper 1, various traceability methods that could be used to improve traceability in continuous processes are identified and described together with their advantages and disadvantages. A mind map connecting different terms of traceability found in the literature is also presented. Further, the mind map describes how traceability may be improved in a continuous process. In Paper 2, a procedure to develop a flow simulation model for a process section to improve traceability is presented. The constructed flow model is then used to simulate the product flow in the pelletizing plants at LKAB. In Paper 3, a novel method to create traceability in a granular product flow using radio frequency identification (RFID) technique is presented. RFID is a wireless and automatic data capturing technique. The method showed promising results when it was initially tested at a conveyor. In Paper 4, the RFID technique is tested in two full scale experiments in a distribution chain of iron ore pellets at LKAB. Different types of RFID- tags and tag containers are tested in the experiments. The results of the experiments show that the RFID technique can be used to improve traceability in the distribution chain. Finally, the results from the research study illustrate that it may be possible to improve traceability in continuous processes by applying the presented traceability methods.

  • 6.
    Kvarnström, Björn
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Improving traceability in continuous processes using flow simulations2012Inngår i: Production planning & control (Print), ISSN 0953-7287, E-ISSN 1366-5871, Vol. 23, nr 5, s. 396-404Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Traceability is normally difficult to achieve in continuous processes, since there are no natural batch structures. In this article, we demonstrate flow-based simulation using process data to improve traceability in a continuous pelletising process. Using the simulation model, the engineers could test the impacts of process disturbances, identify cause and effect relations and aid control in case of process disturbances. In a field trial where the chemistry of an additive was varied during production of a special product, the simulation forecasts predicted the level of the chemical content after the plant within the errors that the engineers found acceptable.

  • 7. Kvarnström, Björn
    et al.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Using process knowledge for simulations of material flow in a continuous process2008Inngår i: Proceedings of the 18th International Conference on Flexible Automation and Intelligent Manufacturing: June 30th - July 2nd, 2008, Skövde, Sweden / [ed] Leo J. de Vin, 2008, s. 1138-1145Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In continuous process industries, large investments in automated process control systems are made to reduce variance, but the variance in key process parameters often remain unchanged. One reason is that the operators often lack tools to assess the impact of process changes on the final product properties. Dynamic simulation could be used to estimate effects of attempted changes, on models with current process information and dynamics. However, the use of dynamic simulation for such purposes is infrequent in process industry. Therefore, the purpose of this paper is to outline a simulation model for mineral processing using existing process knowledge. An iron ore pelletizing process was studied, and process knowledge was collected through interviews and research reports. The material flow mechanisms of a critical process section were also determined experimentally. A simulation model of the process was constructed in SIMULINK, and the effects of various variations were tested. The statistical properties of the output distribution of particle residence times were compared for various settings. Finally, various applications field in a mineral process for the simulation model is discussed, for example, predicting or explaining effect of corrective actions.

  • 8. Kvarnström, Björn
    et al.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Vännman, Kerstin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Matematiska vetenskaper.
    RFID to improve traceability in continuous granular flows: an experimental case study2011Inngår i: Quality Engineering, ISSN 0898-2112, E-ISSN 1532-4222, Vol. 23, nr 4, s. 343-357Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Traceability is important for identifying the root-causes of production related quality problems. Traceability can often be reached by adding identification markers on products, but this is not a solution when the value of the individual product is much lower than the incurred cost of a marking system. This is the case for continuous production of granular media. The use of Radio Frequency Identification (RFID) technique to achieve traceability in continuous granular flows has been proposed in the literature. We study through experiments different methods to improve the performance of such an RFID system. For example, larger transponders and multiple readers are shown to improve the RFID system performance.

  • 9.
    Kvarnström, Björn
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Lindgren, Tore
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Monte Carlo simulation of an radio frequency identification system with moving transponders using the partial element equivalent circuit method2010Inngår i: IET Microwaves, Antennas & Propagation, ISSN 1751-8725, E-ISSN 1751-8733, Vol. 4, nr 12, s. 2069-2076Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    When designing an radio frequency identification system it is important to take both the position and the movement of the transponders into account. In this study, a simulation method that enables the description of a complete RFID system including moving and rotating transponders as well as a complex, industrial environment is presented. By using the partial element equivalent circuit method to calculate the magnetic field generated by the reader antenna and describing the transponders using a magnetic dipole, it is possible to use the Monte Carlo method to describe the dynamic behaviour of the complete system. The method is used in this study to describe the difference in performance between two different reader antennas and these results are also compared to measurements of similar systems operating in an industrial environment. The difference in performance between the two systems is similar in both the simulations and the measurements. A small discrepancy was seen between the results from the simulations and the measurements which is for the most part because of the limited read rate of the RFID systems used in the measurements.

  • 10.
    Kvarnström, Björn
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Nordqvist, Sofia
    LKAB.
    Modelling process flows in continuous processes with radio frequency identification technique2008Inngår i: Scanmet III: 3rd International Conference on Process Development in Iron and Steelmaking, 8-11 June 2008, Luleå, Sweden, Luleå: MEFOS , 2008, Vol. 1, s. 253-262Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Sources of disturbances are often difficult to identify in continuous processes, as the process flows are complex. There are, however, several methods that can be used to monitor flows in complex processes and thereby to improve traceability. Radio frequency identification (RFID) technique is one such method that has been extensively used in parts production for improving traceability. The application of the technique in continuous processes is, however, sparse. The RFID technique offers the possibility to create unique tags with different characteristics that can be detected at specific locations in the process flow. With RFID, virtual batches, possible to follow through the production process, could be created in many types of continuous processes. To report the suitability of using RFID in continuous processes, experiments were conducted in a distribution chain of iron ore pellets produced at LKAB in Malmberget. In a set of experiments eight tag containers were added to the product flow to test the behavior and ability of tag readers to detect the different containers. Three characteristics were varied among the containers: shape, coating mixture and size of tag. The results from the experiments show that large tags increase the read rate, and that no significant effect on read rate could be detected when coating mixtures and shapes were shifted. A conclusion is that the RFID technique could be used to improve traceability in the distribution chain for pellets. Finally, different advantages of improved traceability in continuous processes are discussed.

  • 11.
    Kvarnström, Björn
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Oghazi, Pejman
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Methods for traceability in continuous processes: experience from an iron ore refinement process2008Inngår i: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 21, nr 10, s. 720-730Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Every production process is exposed to disturbances leading to production of defective products. The disturbances are seldom immediately discovered, and need to be traced afterwards. Traceability, or the ability to follow a product through the process, is therefore vital since it aids the localisation of the source of the disturbance. Traceability has for a long time been a possibility in part production, but in the continuous process industry it is still problematic. Examples of problems are complex flows, closed systems and large buffers. Hence, the purpose of this paper is to describe methods that can be used to achieve traceability in continuous processes, and give an example of when they may be applied. To identify suitable traceability methods, the literature search was conducted as well as discussions with researchers from the process industry. How the methods work is presented together with their advantages and disadvantages. Furthermore, an example of which traceability methods could be used for achieving traceability in a continuous iron ore refinement process is given. Seeing the diversity of available methods, achieving traceability in continuous processes should be possible.

  • 12.
    Kvarnström, Björn
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Oja, Johan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik. SP Trätek, SP Technical Research Institute of Sweden.
    Applications of RFID to improve traceability in continuous processes2010Inngår i: Sustainable Radio Frequency Identification Solutions, Vienna, Austria: IN-TECH, 2010, s. 69-86Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 13. Kvarnström, Björn
    et al.
    Vanhatalo, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Using RFID to improve traceability in process industry: experiments in a distribution chain for iron ore pellets2010Inngår i: Journal of Manufacturing Technology Management, ISSN 1741-038X, E-ISSN 1758-7786, Vol. 21, nr 1, s. 139-154Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose: The purpose of the article is to explore the application of Radio Frequency Identification (RFID) to improve traceability in a flow of granular products and to illustrate examples of special issues that need to be considered when using the RFID technique in a process industry setting.Design/methodology/approach: The article outlines a case study at a Swedish mining company including experiments to test the suitability of RFID to trace iron ore pellets (a granular product) in parts of the distribution chain.Findings: The results show that the RFID technique can be used to improve traceability in granular product flows. A number of special issues concerning the use of RFID in process industries are also highlighted, for example, the problems to control the orientation of the transponder in the read area and the risk of product contamination in the supply chain.Research limitations/implications: Even though only a single case has been studied, the results are of a general interest for industries that have granular product flows. However, future research in other industries should be performed to validate the results.Practical implications: The application of RFID described in this article makes it possible to increase productivity and product quality by improving traceability in product flows where traceability normally is problematic. Originality/value: Prior research has mainly focused on RFID applications in discontinuous processes. By contrast, this article presents a novel application of the RFID technique in a continuous process together with specific issues connected to the use of RFID.

  • 14. Oghazi, Pejman
    et al.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Tano, Kent
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Kvarnström, Björn
    Traceability by multivariate analysis on morphology data from grinding circuit2008Inngår i: Conference in Minerals Engineering, Luleå, 2008, s. 81-95Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    LKAB has started a new pelletization plant at Malmberget, the raw material is a mix from Kiruna and Malmberget. To achieve good products it is important to have a good control over the input material in the concentrators that is why the traceability of the process is a crucial factor. However, creating traceability in continuous processes imply vast challenges: process flows can be parallel, serial and reflux; sub processes can be continuous as well as batch-wise; large buffers; no interruptions in product handling. These challenges imply that loads of data from the material is needed for creating traceability. In this case the grinding sections have been in focus and the data are collected from the old and the new grinding sections. The main task is to find a way to make the traceability easy and practical. One way to reach good traceability would be to find a process mineralogical signature or identification. For having a good traceability we need information from the system. It is important to analyze and look into the variables that have a crucial importance to the process. By using Particle Texture analysis a good overview of how magnetite is liberated or associated to others minerals is shown. More important is that morphological data is produced for each mineral in the process. The number o variables made it difficult to compare the result, and by using multivariate analysis such as Principal Component Analysis (PCA) it is possible to have a better insight from the collected data.

  • 15.
    Vanhatalo, Erik
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Kvarnström, Björn
    Bergquist, Bjarne
    Vännman, Kerstin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Matematiska vetenskaper.
    A method to determine transition time for experiments in dynamic processes2009Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Planning, conducting, and analyzing experiments performed in dynamic processes, such as continuous processes, highlight issues that the experimenter needs to consider, for example, process dynamics (inertia) and the multitude of responses. Dynamic systems exhibit a delay (transition time) the change of an experimental factor and when the response is affected. The transition time affects the required length of each experimental run in dynamic processes and long transition times may call for restrictions of the randomization of runs. By contrast, in many processes in parts production this change is almost immediate. Knowledge about the transition time helps the experimenter to avoid experimental runs that are either too short for a new steady-state to be reached, and thus incorrect estimation of treatment effects, or unnecessarily long and costly. Furthermore, knowing the transition time is important during analysis of the experiment.Determining the transition time in a dynamic process can be difficult since the processes often are heavily instrumented with a multitude of responses. The process responses are typically correlated and react to the same underlying events. Hence, multivariate statistical tools such as principal component analysis (PCA) are often beneficial during analysis. Furthermore, the responses are often highly positively autocorrelated due to frequent sampling. We propose a method to determine the transition time between experimental runs in a dynamic process. We use PCA to summarize the systematic variation in a multivariate response space. The time series analysis techniques ‘transfer function-noise modeling' or ‘intervention analysis' are then used to model the dynamic relation between an input time series event and output time series response using the principal component scores. We illustrate the method by estimating the transition time for treatment changes in an experimental blast furnace. This knowledge provides valuable input to the planning and analysis phase of the experiments in the process.

  • 16.
    Vanhatalo, Erik
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Kvarnström, Björn
    Bergquist, Bjarne
    Vännman, Kerstin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Matematiska vetenskaper.
    A method to determine transition time for experiments in dynamic processes2011Inngår i: Quality Engineering, ISSN 0898-2112, E-ISSN 1532-4222, Vol. 23, nr 1, s. 30-45Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Process dynamics is an important consideration during the planning phase of designed experiments in dynamic processes. After changes of experimental factors, dynamic processes undergo a transition time before reaching a new steady state. To minimize experimental time and reduce costs and for experimental design and analysis, knowledge about this transition time is important. In this article, we propose a method to analyze process dynamics and estimate the transition time by combining principal component analysis and transfer function-noise modeling or intervention analysis. We illustrate the method by estimating transition times for a planned experiment in an experimental blast furnace.

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