Suitability of pulverised coal testing facilities for blast furnace applications

Bösenhofer, Markus; Wartha, Eva-Maria; Jordan, Christian; Feilmayr, Christoph; Stocker, Hugo; Hauzenberger, Franz; Rieger, Johannes; Tjaden, Stefan; Walk, Arleen; Harasek, Michael

doi:10.1080/03019233.2019.1565152

Cited by 6 publications

(4 citation statements)

References 57 publications

(165 reference statements)

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“…This approach is referred to as loose coupling in the literature [47] and requires suitable time stepping and mesh resolution [48]. The boundary conditions of the fluid are representative for the pulverized particle jet entering the raceway zone of blast furnaces [21,49]. Temperatures were kept constant at 2500 K, outlet pressure was set to 5 bar (a) , while the inlet velocity was varied according to Table 1.…”

Section: Synthetic Particle Clustermentioning

confidence: 99%

“…Depletion of the gaseous educts in clusters reduces conversion rates compared to single particles [16][17][18][19]. Temperatures also significantly influence conversion rates due to their non-linear correlation described by the Arrhenius law [20,21]. Therefore, overpredicting temperatures results in an over-prediction of the thermochemical conversion rates and can give misleading results for process optimization.…”

Section: Introductionmentioning

confidence: 99%

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Heat Transfer Models for Dense Pulverized Particle Jets

2022

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Heat transfer is a crucial aspect of thermochemical conversion of pulverized fuels. Over-predicting the heat transfer during heat-up leads to under-estimation of the ignition time, while under-predicting the heat loss during the char conversion leads to an over-estimation of the burnout rates. This effect is relevant for dense particle jets injected from dense-phase pneumatic conveying. Heat fluxes characteristic of such dense jets can significantly differ from single particles, although a single, representative particle commonly models them in Euler–Lagrange models. Particle-resolved direct numerical simulations revealed that common representative particles approaches fail to reproduce the dense-jet characteristics. They also confirm that dense clusters behave similar to larger, porous particles, while the single particle characteristic prevails for sparse clusters. Hydrodynamics causes this effect for convective heat transfer since dense clusters deflect the inflowing fluid and shield the center. Reduced view factors cause reduced radiative heat fluxes for dense clusters. Furthermore, convection is less sensitive to cluster shape than radiative heat transfer. New heat transfer models were derived from particle resolved simulations of particle clusters. Heat transfer increases at higher void fractions and vice versa, which is contrary to most existing models. Although derived from regular particle clusters, the new convective heat transfer models reasonably handle random clusters. Contrary, the developed correction for the radiative heat flux over-predicts shading effects for random clusters because of the used cluster shape. In unresolved Euler–Lagrange models, the new heat transfer models can significantly improve dense particle jets’ heat-up or thermochemical conversion modeling.

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Section: Synthetic Particle Clustermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Heat Transfer Models for Dense Pulverized Particle Jets

2022

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“…An overview on such facilities is given in Ref. [53]. Based on the test results, the PC conversion degree or burnout rate is determined by means of [41,54,55]: .…”

Section: Examination Of the Conversion Efficiencymentioning

confidence: 99%

“…An overview on such facilities is given in Ref. [53]. Based on the test results, the PC conversion degree or burnout rate is determined by means of [41,54,55]: off -gas analysis using the nitrogen balance ash content of the parent coal and collected residues or carbon and ash contents of the parent coal and residues. …”

Section: Characteristics Of Selected Ara and Conversion Behaviour In ...mentioning

confidence: 99%

Blast furnace injection for minimizing the coke rate and CO₂emissions

Babich

2021

Ironmaking & Steelmaking

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The tuyère injection is one of the key tools to exhaust the blast furnace potential and to minimize its CO 2 emissions. The review argues theoretical basis and operation strategies for ensuring the high efficiency of injection of auxiliary reducing agents (ARA). First, it provides the theoretical analysis of requirements that ensure minimum coke and carbon rates, and minimum CO 2 emissions. Then it focuses on the injection of selected ARA, such as pulverized coal, biomass products, and hydrogen containing gasesnatural gas, coke oven gas and pure H 2 . Conversion behaviour of mentioned ARA and measures for its intensifying are discussed critically. Next, compensating measures and their suitable level are discussed. The role of oxygen and ways for its introduction are discussed from different points of view. Operating windows and co-injection of solids and H 2 gases are discussed aiming at the best blast furnace performance. Finally, limiting factors for injection of ARA are summarized.

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