Numerical model incorporating different oxidizer in a reheating furnace fired with natural gas

Landfahrer, Martin; Schluckner, Christoph; Gerhardter, Hannes; Zmek, Thomas; Klarner, Jürgen; Hochenauer, Christoph

doi:10.1016/j.fuel.2020.117185

Cited by 16 publications

(4 citation statements)

References 35 publications

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“…The distribution of oxygen and water vapour in a furnace are not equal, though. Models have shown that water vapour is distributed much more equally in a reheating furnace than oxygen [34]. As such, an increase in water vapour content in the furnace through oxyfuel burning should bring forth a more homogenous scale formation increasing effect than would an increase in oxygen content.…”

Section: Introductionmentioning

confidence: 99%

The Atmosphere’s Effect on Stainless Steel Slabs’ Oxide Formation in a CH4-Fuelled Reheating Furnace

Laukka

Heikkinen

Fabritius

2021

Metals

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Utilising the oxyfuel practice for CH4-fuelled combustion has positive effects on the emissions, efficiency and cost of high temperature furnace practices. However, especially in older installations, oxyfuel usage requires retrofitting and alters the atmosphere in which the oxidation of the steel occurs, when compared to using air as the oxidiser. Stainless steel slab oxide growth during reheating was studied in different atmospheres. The simulated post-burn atmospheres from oxyfuel, lean oxyfuel and air-fuel practices were used to compare oxide-scale layer growth and morphology during simulated typical AISI 304 stainless steel slab reheating prior to hot rolling. Thermogravimetric measurements, glow discharge optical emission spectrometer (GDOES) and field-emission scanning electron microscope energy dispersive X-ray (FESEM-EDS) methodology were applied to discern differences between oxide growth and inner oxide layer morphology between the three practices. Switching from air to oxyfuel practice at a single temperature had the same increasing effect on the scale formation amount as a 25 °C temperature increase in air atmosphere. Inner oxide layer depth profiling revealed C, Si and Ni to be the main elements that differed between temperatures and atmospheres. A morphology study showed Si and Ni behaviour to be linked to breakaway oxidation.

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Section: Introductionmentioning

confidence: 99%

The Atmosphere’s Effect on Stainless Steel Slabs’ Oxide Formation in a CH4-Fuelled Reheating Furnace

Laukka

Heikkinen

Fabritius

2021

Metals

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“…The EDC model suggested by Magnussen is an improvement of the EDM, allowing the description of detailed chemical mechanisms. The model has been applied to several combustion simulations under oxygen-enriched and air-fuel conditions. ,, The EDC model assumes that reactions occur in fine scales. The time scale of mass transfer between surroundings and fine scales is calculated using eq , and the length fraction of the fine scales is defined using eq . where C τ represents the time scale constant with a value of 0.4082 and C ξ represents the volume fraction constant with 2.1337.…”

Section: Numerical Modelsmentioning

confidence: 99%

“…In addition, the outer wall of the furnace and the slab boundary were treated as the convective boundary conditions and the coupled wall conditions, respectively. The heat transfer coefficient between the outer wall of the furnace and the external air is 10 W/(m 2 K) and the external air temperature is 298.15 K. The emissivity of the furnace wall is 0.7. , Since the slab surface is smooth and nonoxidized, the slab wall emissivity is 0.5. The density of each slab was set to 7940 kg/m 3 .…”

Section: Numerical Modelsmentioning

confidence: 99%

“…Landfahrer et al developed a model to investigate the combustion and heat transfer in a rotary hearth direct-fired furnace using a numerical method similar to that used by Prieler et al The model revealed the existing problems of this type of furnace and provided reasonable suggestions. Further investigations on the impacts of different oxidizers in a direct-fired furnace were performed by Landfahrer et al They considered various oxidizers and fuels in these parts of the furnace by dividing the whole domain into several parts. Hu et al studied the effect of flameless oxy-fuel combustion on the heating efficiency of the furnace.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Analysis of the Effects of Oxygen-Enriched and Different Inlet Conditions on Performance of an Indirect Reheating Furnace with Pulse Combustion

et al. 2021

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The requirement of improving efficiency and performance leads to the continuous development of furnaces and burners. For this purpose, it is necessary to establish a model suitable for industrial production and adjust it according to industrial demand. In this paper, a comprehensive numerical model is developed to characterize the combustion, heat transfer, and slab heating in an indirect reheating furnace with pulse combustion. To realize the pulse combustion process, a pulse control approach based on a user-defined function (UDF) was proposed to control the radiant tube burner state. Indirect heat transfer in the furnace was realized by coupling the radiant tubes and the furnace as a whole. In a simulation with the eddy dissipation concept (EDC) model, results from the four-step mechanism were in close accordance with those of the GRI 3.0 mechanism, and both mechanisms could describe the combustion process in detail. However, the calculation time of the EDC model with the four-step mechanism was reduced significantly. Thus, the EDC model with the four-step mechanism was selected as the ideal combustion model used for further simulation research. Through experimental validation, the simulation results of the developed model using the EDC model with the four-step mechanism showed a good agreement with the experimental results. Additionally, with this model, the effects of oxygen-enriched combustion with 74 vol % N2 and 26 vol % O2 in the oxidizer and inlet-change case with a fuel inlet and a primary air inlet on the performance of an indirect reheating furnace with pulse combustion were specially studied. The maximum flame temperature and the average temperature of the furnace atmosphere increased from 2046 to 2175 K and from 1241 to 1279 K for increased oxygen concentration, respectively. Compared with air-fuel combustion, the discharging slab temperature reached a growth of 2.9% in oxygen-enriched combustion. After changing the inlet boundary of the radiant tube burners, since the excessive combustion in the burner’s combustion chamber was avoided and the full combustion of fuel in the radiant tubes was promoted, the flame intensity in the radiant tubes was enhanced and the maximum flame temperature reached 2196 K. At the same time, the mole fraction of CO at the outlet became smaller and the slab temperature in all zones of the furnace increased by more than 3.5%. This study showed that higher efficiency of an indirect reheating furnace with pulse combustion can be achieved by oxygen-enriched combustion and changing the inlet boundary of the burners.

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Effect of Residual Elements during the Hot‐Working Process of Steel Production: A Critical Review

Kapoor,

Davis,

2024

steel research int.

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Demand for steel scrap as feedstock for steelmaking increases, allowing the production of steel with lower energy costs and reduced CO2 emissions. In general, steel scrap may contain high levels of undesirable residual elements, which may contribute to processing challenges such as surface hot‐shortness, bulk hot‐shortness, hot‐brittleness, and higher rolling loads during the hot‐working process of steel production. The effect of different residual elements during the hot‐deformation process is a broad topic and involves the understanding of both individual and combined behavior of residual elements for different thermal and mechanical conditions that arise. In this article, the behavior of various residual elements is critically reviewed, individually and synergistically at high temperatures during the hot‐working process (i.e., reheat furnace stage, descaling stage, and deformation stage) of steel production, with a focus on (surface) hot‐shortness, delayed recrystallization, and higher rolling loads caused by the residual elements. Herein, it is aimed to help the steel community to identify challenges and opportunities in efficiently utilizing steel scrap.

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Numerical model incorporating different oxidizer in a reheating furnace fired with natural gas

Cited by 16 publications

References 35 publications

The Atmosphere’s Effect on Stainless Steel Slabs’ Oxide Formation in a CH4-Fuelled Reheating Furnace

The Atmosphere’s Effect on Stainless Steel Slabs’ Oxide Formation in a CH4-Fuelled Reheating Furnace

Numerical Analysis of the Effects of Oxygen-Enriched and Different Inlet Conditions on Performance of an Indirect Reheating Furnace with Pulse Combustion

Effect of Residual Elements during the Hot‐Working Process of Steel Production: A Critical Review

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