| 1. |
- Brämming, Mats, et al.
(författare)
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BOS vessel vibration measurement for foam level detection
- 2011
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Ingår i: ISIJ International. - : Iron and Steel Institute of Japan. - 0915-1559 .- 1347-5460. ; 51:1, s. 71-79
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Tidskriftsartikel (refereegranskat)abstract
- In the BOS process liquid slag together with dispersed metal droplets, solid particles and process gases form an expanding foam. Certain process conditions may lead to excessive foam growth, forcing foam out through the vessel mouth, an event commonly known as 'slopping'. Slopping results in loss of valuable metal, equipment damage and lost production time. In the early 1980s a system for foam level and slopping control was installed at SSAB's steel plant in Luleå, a system based on the correlation between BOS vessel vibration in a narrow low frequency band and foam development. The technique, in this case with an accelerometer mounted on the trunnion bearing housing, soon showed its usefulness, for example when adapting existing lance patterns to a change in oxygen lance design from a 3-hole to a 4-hole nozzle. Estimating the actual foam height in the BOS vessel was of great importance in the recently completed RFCS funded research project "IMPHOS" (Improving Phosphorus Refining). Based on the earlier positive experiences, it was decided to further develop the vessel vibration measurement technique. Trials on an industrial size BOS vessel type LD/LBE have been carried out, this time with a tri-axial accelerometer mounted on the vessel trunnion. FFT spectrum analysis has been used in order to find the frequency band with best correlation to the foam level development. The results show that there is a correlation between vessel vibration and foam height that can be used for dynamic foam level and slopping control. © 2011 ISIJ.
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| 2. |
- Brämming, Mats, et al.
(författare)
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Comparison between vessel vibration and audiometry for slopping control in the top-blown BOS process
- 2011
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Ingår i: Steel Research International. - : Wiley. - 1611-3683 .- 1869-344X. ; 82:6, s. 683-692
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Tidskriftsartikel (refereegranskat)abstract
- Excess slag foam growth is a frequent problem in the BOS process. In the worst case, foam is forced out of the vessel and this phenomenon, commonly called slopping, not only results in loss of valuable metal yield but also in equipment damage and lost production time. In order to minimize slopping, accurate estimation of the foam level inside the vessel is an important part of BOS process control. In the top blown BOS vessel, slopping control is achieved using both static and dynamic measures. The most common implemented technique for dynamic foam height estimation and slopping control is the audiometer system. An alternative method, vessel vibration monitoring, has been investigated as part of the work in a RFCS funded research project called IMPHOS. In order to judge the usefulness of this method, parallel vibration and audio measurements have been carried out on 130 tonne as well as on 300 tonne BOS vessels. The results show that during stable process conditions there is good agreement between the two methods with regard to foam height estimation and, as vessel vibration and audiometry are largely independent of each other, a combination of the two is likely to increase significantly the accuracy of slopping prediction. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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| 3. |
- Hahlin, Pär, et al.
(författare)
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Raceway depth measurements in the blast furnace using microwave technology
- 2006
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Ingår i: 4th International Congress on the Science and Technology of Ironmarking, ICSTI 2006, Proceedings. ; , s. 504-507
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Konferensbidrag (refereegranskat)abstract
- Attempts to control the raceway depth have been made with many different technologies however none of them have had the capability to measure during operation. By using microwave technology the problem with interfering obstacles such as the coal injection can be avoided since the technology is not susceptible to this kind of interference. In this paper a novel approach using microwave technology to measure the raceway variations during operation will be described. MEFOS, The Metallurgical Research Institute AB, Lulea, Sweden, has tested an especially developed microwave unit to continuously measure the variations of the raceway during operation in the Blast Furnace. The trials were performed as a single tuyère trial on Blast Furnace 3 at SSAB Tunnplat AB, Lulea, Sweden with excellent results.
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| 4. |
- Malmberg, Donald, et al.
(författare)
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In-Situ Monitoring of Oxygen Concentration and Gas Temperature in a Metallurgical Process Using Diode-Laser Spectroscopy :
- 2001
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Increased demands on quality control, reduced production-time, energy savings and reduction of green-house-gas emission in various metallurgical processes have created an interest for new methods to monitor and control the processes. By using Tunable Diode Laser spectrometers the gas temperature as well as the concentration of 0 2, CO and C02 have been monitored. Laboratory experiments were carried out in a specially designed high-temperature furnace at MEFOS to determine a set of absorption lines suitable for simultaneous 02ffemperature and CO/COz measurements. Field trials were carried out in an Electric Arc Furnace and a reheating furnace.
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| 5. |
- Malmberg, Donald, et al.
(författare)
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In-Situ Monitoring of Oxygen Concentration and Gas Temperature in a Metallurgical Process Using Diode-Laser Spectroscopy
- 2000
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- By using a Tunable Diode Laser spectrometer the oxygen concentration and the temperature in the off-gases of an electric arc furnace, EAF, have simultaneously been monitored during operation. The spectrometer operates at a group of absorptoin lines lines in the near infrared wavelength region to measure the oxygen concentration and the temperature. The O2 absotion line parameters used were determined in a controlled pilot experiment using a heated measurement path. The temperature is measured using the relative intensity of the absoption lines and thereafter concentration is calculated from the temperature compensated absorption. The measurements were performed in-situ with a specially designed high temperature sensor mounted on the furnace wall. Optical fibers were used to carry the probing light between the TDL spectrometer and the measurement point. This novel work shows the potential of using TDL spectrometer to measure O2 and temperature in-situ in a steel making process.
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| 6. |
- Malmberg, Donald
(författare)
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Innovative Contact Free Sensors for Metallurgical Process Control
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The steel- and metal industry has an extensive production processing comprising many different process steps of solid, gaseous and liquid nature. Thus it is obvious that a number of different measurement technologies must be used to collect and evaluate key physical parameters which are necessary to control the production processes. In this respect, the software to monitor the processes have, during the past decade, undergone extensive improvement whilst the sensors reading off the instantaneous process status have not and are still afflicted with severe drawbacks.This situation, in combination with increased demands on energy savings and rules regarding reduction of green house gas emission (the Kyoto protocol), has created incentives for the development and implementation of new technologies to monitor and control production processes in the steel and metal industry.The objectives in this thesis are to develop and evaluate sensor technology that can be used for in-situ on line analysis of metallurgical processes.The work is divided into:- To test and evaluate microwave technology for on line slag analysis.- To design, develop and evaluate microwave sensors for off gas analysis.- To evaluate laser sensors for simultaneous analysis of the process environment in metallurgical processes with emphasis on measuring the oxygen concentration and temperature in a steel reheating furnaceDuring the work on slag a broad band antenna was used for the microwave investigations on solid and liquid slag. The results show that it is possible to evaluate a refractive index for both solid and liquid slag. The results also show that there is a weak correlation between the refractive index for liquid slag and slag basicity.Trials on off gases from a pilot process as well as a full scale metallurgical production processes have been performed with microwave technology. The instrument used for the microwave trials has been developed from individual components. The results show that it is possible to use the technology for process analysis however the data collected regarding individual spectral lines still remain to be correlated to known molecular frequencies.Laser technology for gas analysis is a known technology in many different industrial applications. However, using the technology in steel and metal production processes requires that the technology must be adapted to the environment specific to those processes. Trials on a pilot process has been performed to find a suitable set of O2 absorption line parameters to be used during the forthcoming trials of full scale production processes. The outcome of these trials clearly show that the TDLAS technology can be used successfully on reheating furnaces but have a limited application potential on the LD converter process as well as the EAF.The benefit of the presented work will on production scale contribute to a lowered emission of green house gases, lowered energy consumption and an improved production yield.
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| 7. |
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| 8. |
- Malmberg, Donald, et al.
(författare)
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Microwave Technology in Steel and Metal Industry, an Overview
- 2007
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Ingår i: ISIJ International. - Tokyo : Nippon Tekko Kyokai. - 0915-1559 .- 1347-5460. ; 47:4, s. 533-538
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Tidskriftsartikel (refereegranskat)abstract
- In many metallurgical operations, effective analysis of the processes can be very difficult with available technology. This is especially true if the analysis is to be performed on-line and in a harsh environment characterized by high temperatures, dust and liquid metal. Protection of the equipment requires both rugged encapsulation as well as elaborate sampling systems and exposure of the equipment to the hazardous environment must be minimised. Often this result in an increased level of service and maintenance requirements and, in the worst case, the maintenance cost might be so high that the equipment is not installed. Microwave technology is a versatile and powerful tool with many different applications in the scientific community. It is insensitive to dust and fume and, for several years, the technology has been tested at MEFOS and evaluated for different metallurgical processes. It has been applied to slag thickness measurement and slag composition in an induction furnace, 3D imaging of the burden surface in a charging model on pilot scale as well as raceway depth measurements in a Blast Furnace. The idea of using microwave technology for gas analysis in metallurgical processes has also been explored. However, despite its many advantages, microwave technology is still not employed extensively in the steel and metal industries. Copyright © 2007 ISIJ.
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| 9. |
- Malmberg, Donald, et al.
(författare)
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On-line Gas Analysis using Microwave Technology
- 2003
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Ingår i: Proceedings Symposium on steel production. ; , s. 11-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Microwave technology has for decades been a tool for astronomers in their work to map and understand the complexities of the universe due to composition and extent. The technology is also frequently used on laboratory scale to examine properties of atomic and molecular compounds. Combining the knowledge gained in those these fields of research and transferring it to the environment of the Steel and metal industry, a project to investigate microwave spectroscopy for on-line process control has been launched. Due to the fact that the dynamic in most metallurgical processes as well as combustion processes is very fast and the response time for conventional extractive gas analysers is long, off-gas analysis for on-line process control is not expedient with this technology. On the other hand, by exploiting microwave technology, its short response time and high sensitivity for gas analysis, disadvantages such as long response time could be eliminated, and thus improve the process efficiency. With this approach a process control on-line in “real time” is possible. On- line gas analysis entails an improved process control, which for metallurgical and combustion processes implies energy savings, reduced emissions of green house gases and improved productivity. In this novel work we will present a series of trials in which a high tempered gas flow is spectroscopically analysed in a frequency band ranging from 110 to 120 GHz. The objective is to stimulate compounds sensitive to radiation in this frequency band to make a transition from one energy level to another and in doing so giving up energy that can be detected by the measuring system. Of interest for the steel and metal industry are molecular compounds such as CO, CO2 (isotope), O2, NO, NO2, H2O, OH and SO2.
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| 10. |
- Malmberg, Donald, et al.
(författare)
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Preliminary microwave measurements on liquid stags
- 2005
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Ingår i: Ironmaking & steelmaking. - London : Maney Publishing. - 0301-9233 .- 1743-2812. ; 32:1, s. 61-67
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Tidskriftsartikel (refereegranskat)abstract
- Microwave technology has for decades been a tool for astronomers in their work to map and understand the complexities of the universe in terms of composition and extent but it is also used at laboratory scale by spectroscopists to examine the properties of atomic and molecular compounds. This paper discusses the use of microwave technology for the investigation of liquid slag structures. Preliminary results indicate that alteration of slag composition could be correlated to the measured microwave refractive index. Investigations have been performed on Al2 O3 -CaO-SiO2.
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