| 1. |
- Bölke, Kristofer, et al.
(författare)
-
Experimental Determinations of Mixing Times in the IronArc Pilot Plant Process
- 2019
-
Ingår i: Metals. - : MDPI. - 2075-4701. ; 9:1
-
Tidskriftsartikel (refereegranskat)abstract
- IronArc is a newly developed technology and an emerging future process for pig iron production. The long-term goal with this technology is to reduce the CO2 emissions and energy consumption compared to existing technologies. The production rate of this process is dependent on the stirring, which was investigated in the pilot plant process by measuring the mixing time in the slag bath. Moreover, slag investigations were done both based on light optical microscope studies as well as by Thermo-Calc calculations in order to determine the phases of the slag during operation. This was done because the viscosity (which is another important parameter) is dependent on the liquid and solid fractions of the slag. The overall results show that it was possible to determine the mixing time by means of the addition of a tracer (MnO2 powder) to the slag. The mixing time for the trials showed that the slag was homogenized after seconds. For two of the trials, homogenization had already been reached in the second sample after tracer addition, which means <= 8 s. The phase analysis from the slag indicated that the slag is in a liquid state during the operation of the process.
|
|
| 2. |
- Bölke, Kristofer, et al.
(författare)
-
Importance of the Penetration Depth and Mixing in the IRONARC Process
- 2018
-
Ingår i: ISIJ International. - : Iron and Steel Institute of Japan. - 0915-1559 .- 1347-5460. ; 58:7, s. 1210-1217
-
Tidskriftsartikel (refereegranskat)abstract
- One of the most important parameters for gas injection into liquid baths is the penetration depth of the gas into the bath. This is due to that it strongly influences the flow structure and hence the stirring and plume behavior in metallurgical processes. The IRONARC process is a new energy efficient process for reduction of iron oxide to produce pig iron. The future goal is to continuously scale up the process to an industrial scale from the current pilot scale. In this process, gas is injected horizontally through a submerged nozzle into a slag bath. Hence, the penetration depth is of great importance since it greatly affect several parameters in this process. Moreover, this information is essential when scaling up the reactor from a pilot scale to an industrial scale. In this work, the penetration depth of gas injection into water in a small scale side blown converter was studied numerically. Two different approaches with different multiphase models were tested, namely the Volume of Fluid (VOF) model and Eulerian multiphase model (EE). The penetration depth could be accurately determined for both numerical models, with a small expected deviation of 13.9% from the physical experiment results. Also, the simulation time was shorter for the Eulerian multiphase model. The penetration depth was then determined for the IRONARC pilot plant process. The results show that the plume is detached from the nozzle wall, which in turn results in a better energy usage of the gas along with a small refractory wear.
|
|
| 3. |
- Svantesson, Jonas, 1994-, et al.
(författare)
-
Numerical Analysis of Slag Transfer in the IronArcProcess
- 2020
-
Ingår i: Metallurgical and materials transactions. B, process metallurgy and materials processing science. - : Springer Nature. - 1073-5615 .- 1543-1916. ; 51, s. 2171-2186
-
Tidskriftsartikel (refereegranskat)abstract
- The IronArc process is a novel approach to ironmaking which aims to reduce the associatedCO2 emissions. By superheating gas using electricity in a plasma generator (PG) the heatrequired for the process can be supplied without burning of coke. Reduction of hematite andmagnetite ores is facilitated by additions of hydrocarbons from liquid natural gas (LNG). Themelting and reduction of ore will produce a molten slag containing 90 pct wüstite, which will becorrosive to most refractory materials. A freeze-lining can prevent refractory wear by separatingthe molten slag from the refractory. This approach is evaluated in CFD simulations by studyingthe liquid flow and solidification of the slag using the enthalpy–porosity model in two differentslag transfer designs. It was found that a fast moving slag causes a high near-wall turbulence,which prevents solidification in the affected areas. The RSM turbulence model was verifiedagainst published experimental research on solidification in flows. It was found to accuratelypredict the freeze-lining thickness when a steady state was reached, but with lacking accuracyfor predicting the time required for formation of said freeze-lining. The results were similarwhen the k-w SST model was used. A design with a slower flow causes more solidified materialon the walls and can protect all areas of the refractory wall from the corrosive slag. A parameterstudy was done on the effect of viscosity, mushy zone parameter, heat conductivity and massflow on the amount of solidified material, thickness of solidified material, heat flux, and wallshear stress. In the current geometry, freeze-linings completely protect the refractory for massflow rates of up to 3 kg s^-1, and are stable for the expected viscosity (0.05 to 0.3 Pa), heatconductivity (2 Wm^-1 K^-1) and used mushy zone parameter (10,000).
|
|
| 4. |
- Svantesson, Jonas, 1994-, et al.
(författare)
-
Study of Dynamic Refractory Wear by Slags Containing Very High FeO Contents under Steelmaking Conditions
- 2021
-
Ingår i: Ironmaking & steelmaking. - : Taylor & Francis. - 0301-9233 .- 1743-2812. ; 48:5, s. 607-618
-
Tidskriftsartikel (refereegranskat)abstract
- The wear of industrial refractory materials was studied in contact with slags containing high amountsof FeO. The thermodynamic equilibrium of the refractory slag systems was determined in Thermocalc® and FactSage™ to predict the chemical wear. Also, the rotating finger technique was used in experiments with fingers of alumina spinel, zirconia, graphite, silicon carbide (SiC), magnesia-carbon(MgO-C), chromite (Cr2O3), and MgO-Spinel (MgO-Al2O3). The fingers were rotated in a FeOx (90w%) -SiO2 (5w%) - CaO (5w%) slag for 3 hours in a molybdenum crucible using a 100 RPM speed and a 1700K temperature. The wear of the refractory fingers was determined by dimensional changes and changes incomposition of the slags. The experimental results suggest that the wear is caused by a combinationof dynamic and chemical wear, which rapidly deteriorated the refractory fingers. Only MgO-spinel based refractories exhibited a partial resistance to wear from slag. The carbon containingrefractories rapidly reacted with the slag causing significant gas formation and a foaming slag. It was found that the thermodynamic equilibrium calculations can be used to indicate if a refractory is stable in a certain slag system, but since many of the experimental systems are not in equilibrium the predictions will not be exact. However, the results of such a study are highly dependent on thequality of the data in the database being used.
|
|
| 5. |
- Svantesson, Jonas, 1994-, et al.
(författare)
-
Study of Dynamic Refractory Wear by Slags Containing Very High FeO Contents under Steelmaking Conditions
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The wear of industrial refractory materials was studied in contact with slags containing high amountsof FeO. The thermodynamic equilibrium of the refractory slag systems was determined in Thermocalc® and FactSage™ to predict the chemical wear. Also, the rotating finger technique was used inexperiments with fingers of alumina spinel, zirconia, graphite, silicon carbide (SiC), magnesia-carbon(MgO-C), chromite (Cr2O3), and MgO-Spinel (MgO-Al2O3). The fingers were rotated in a FeOx (90w%) -SiO2 (5w%) - CaO (5w%) slag for 3 hours in a molybdenum crucible using a 100 RPM speed and a1700K temperature.The wear of the refractory fingers was determined by dimensional changes and changes incomposition of the slags. The experimental results suggest that the wear is caused by a combinationof dynamic and chemical wear, which rapidly deteriorated the refractory fingers. Only MgO-spinelbased refractories exhibited a partial resistance to wear from slag. The carbon containingrefractories rapidly reacted with the slag causing significant gas formation and a foaming slag.It was found that the thermodynamic equilibrium calculations can be used to indicate if a refractoryis stable in a certain slag system, but since many of the experimental systems are not in equilibriumthe predictions will not be exact. However, the results of such a study are highly dependent on thequality of the data in the database being used.
|
|
