Blast-furnace Charging Research Articles

Effects of particle size composition and burden ratio on burden segregation in the blast furnace throat based on DEM

In blast furnace charging, burden segregation affects the distribution of gas flow and the efficiency of chemical reactions, which in turn impacts the overall efficiency and quality of ironmaking. This work developed a bell-less top charging model based on the DEM to analyze burden segregation at the furnace throat under various particle size compositions, chute inclinations, and burden ratios. The results show that the burden exhibits a ring-like distribution around the furnace throat, with smaller particles concentrated in the inner ring near the center. When particle size difference of the burden is significant, adjusting the proportion of large or small particles has a more pronounced effect on particle size segregation near the center of the blast furnace. The smaller the chute inclination, the more serious the particle size segregation of the burden. Pellet tends to accumulate near the center of the blast furnace, with a segregation index reaching 0.8 in this region. Adjusting the burden ratio has a more pronounced effect on the segregation of sinter. This work provides theoretical support for charging optimization in blast furnace operation.

Burden Surface Shape Modeling and Charging Matrix Optimization for the Blast Furnace Charging Process

Burden Surface Shape Modeling and Charging Matrix Optimization for the Blast Furnace Charging Process

A Novel Particle Size Detection System Based on RGB-Laser Fusion Segmentation With Feature Dual-Recalibration for Blast Furnace Materials

Particle size detection (PSD) is used to obtain the particle size distribution of materials in the blast furnace charging process, which is significant for optimizing the gas flow distribution and ensuring stable production. However, due to the complex surface texture of the materials and the uneven illumination of the production environment, existing methods have difficulty obtaining the particle size distribution efficiently. This paper proposes an end-to-end PSD system based on image segmentation to obtain the particle size distribution online with high accuracy. First, to further enhance the expression of edge features and reduce the interference of complex textures, an RGB-laser particle segmentation network (RLPNet) is developed to obtain high-precision segmentation images by camera-LiDAR sensor fusion. Moreover, to improve the fusion of RGB and laser features, a feature dual-recalibration (FDR) module was designed and embedded in RLPNet, consisting of independent recalibration and joint recalibration with T-convolution. Finally, to reduce the error caused by missing edge particle pixels, an edge-recognition-based particle size calculation strategy (ERP) is presented. Experimental results demonstrate that the proposed method performs well on the constructed dataset and in industrial applications. With the segmentation accuracy of RLPNet reaching 64.19 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\%$</tex-math></inline-formula> , the similarity between the particle size distribution predicted with ERP and the actual distribution reaches 79.19 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\%$</tex-math></inline-formula> .

Computational Study of Gas‐Flow and Temperature Dynamics at Blast Furnace Charging

The burden in the blast furnace is charged to form separate layers of ore and coke, which makes it possible to control the conditions in the shaft because the materials have different gas permeabilities and therefore affect the gas distribution in the shaft. Since ore and coke are of fundamentally different densities, the burden mass flux at different radial locations will vary, which influences the heating of the burden upon its descent. To gain an understanding of the effect of charging on the thermal and flow conditions in the upper shaft, the system is analyzed by computational fluid dynamics combined with the discrete element method. A model of the counter‐current flow of gas and solids and the temperature of the two phases in a simplified setup is developed. It simulates the intermittent charging and continuous descent of burden and the simultaneous ascent of gas through the particle bed. The model captures the complex interaction between the solid and gas flows, which affects the radial temperature distribution due to heat transfer and gas redistribution. The dynamics of the system are illustrated and analyzed using a simple charging cycle, and some implications of the findings are discussed.

Еfficiency increase of powdered coal application at hot metal production and limestone calcination under unstable technology conditions

Operation of Ukraine ferrous metallurgy under conditions of dependence on import and instability of energy carriers supply, shortage of investments in modernization of production equipment, make the matter of cooperation between steel-works and research organization particularly actual. Basic results of cooperation between Z.I. Nekrasov Institute of Ferrous metallurgy, NAN of Ukraine and Dnepr steel-works in 2017–2019 on blast sfurnace operation pefection and technology of powdered coal injection into rotating limestone calcination furnaces. Results of the finding of the powdered coal optimal consumption shown, which ensure a high efficiency of the coke substitution, reaching of maximum possible blast furnace productivity as well as satisfactory utilization degree of the reducing gas ability. Results of implementation of a complex of measures presented, which ensure a rational distribution of the powdered coal by BF air tuyeres for making the heat conditions of the tuyere zone even by the blast furnace circle. Efficiency of application of technology of joint injection the powdered coal and natural gas was shown, which is achieved by improving the powdered coal combustion conditions in case of increase their mixing degree. Recommendations quoted for blast furnaces starting-up after their idling for a period exceeding the permissible one, without tapping the plug hot metal. The recommendations ensure an accident-free putting a blast furnace into operation followed by reaching planned parameters. Results of usage sensors information, measuring temperature of gas flow above the charge surface presented. The results allow to prove the correction of blast furnace charging mode by an expert module, generating correction impact to support control actions by technological personal. A complex of measures formed to prevent a disturbance of a blast furnace running in case of powdered coal injection in an amount exceeding 140 kg/t of hot metal and without application of special washover materials. The results of efficiency of the mastered technology, envisaging application manganese-bearing materials at a constant base, were shown. Results of diagnostics of workability of the facility for powdered coal injection into rotating limestone calcinating furnace presented, followed by elaboration recommendation on correction parameters of injection facility operation.

A Mathematical Model Combined with Radar Data for Bell-Less Charging of a Blast Furnace

Charging directly affects the burden distribution of a blast furnace, which determines the gas distribution in the shaft of the furnace. Adjusting the charging can improve the distribution of the gas flow, increase the gas utilization efficiency of the furnace, reduce energy consumption, and prolong the life of the blast furnace. In this paper, a mathematical model of blast furnace charging was developed and applied on a steel plant in China, which includes the display of the burden profile, burden layers, descent speed of the layers, and ore/coke ratio. Furthermore, the mathematical model is developed to combine the radar data of the burden profile. The above model is currently used in Nanjing Steel as a reference for operators to adjust the charging. The model is being tested with a radar system on the blast furnace.

Charge material distribution behaviour in blast furnace charging system

Smooth operation, permeability control and high energy efficiency are critical operational indices which relate to the overall economic measure of the blast furnace (BF) ironmaking process. The BF charging system is central to the realisation of good operational indices. However, the readiness of granular material to segregate (de-mix) due to particle geometry (size, shape, distribution and density) regardless of the material has been uniformly blended, remains a challenge. This research paper presents discrete element modelling (DEM) study to investigate, characterise and compare the effects of initial positioning of high flowability pellets material in ternary ferrous mixtures with two sinter material components of different sizes. In order to elucidate quantification of the particle-particle scale distributions of particle types relative to others as charge materials mix as well as providing useful inferences on segregation and dispersion, a quantitative approach using near-neighbour separation index (NNSI) was used to give instantaneous quantitative description of the material status in space and time during multiple handling state positions within the charging system. Based on the results obtained from the DEM simulations, the initial positioning of the high flowability pellets material in the upstream of the BF charging system has a bearing on the discharge flow characteristics in the downstream discharging operations as well as mixing and segregation behaviour of the material. The mobility of the high flowability pellets particles, compounded by their relatively small size, influence the overall material movement and interactions as they are acquiescent to percolation and sieving. The observations in this study form a significant contribution for considerations of a discharge model formulation for a mathematical model possible of tracking real-time material movements in a BF charging system.

Improving the burdening practice by optimization of raw flux calculation in blast furnace burden

ABSTRACTThe determination of hot metal and slag composition is of utmost importance for the smooth operation of the blast furnace. In the present work, an attempt is made to bridge the gap between theoretical slag composition and actual slag chemistry by encapsulating the theoretical burden calculation with the flux optimization technique. The burden calculation model optimizes the amount of raw material wherein the amount of flux is optimized using matrix operations iteratively to attain the target chemical composition of the slag. Based on the target slag composition, the best combination of fluxes is predicted that closely meets the target slag compositions. The model suggests the optimum amount of fluxes and subsequently, the desired burden matrix setpoints are downloaded to the controller controlling the blast furnace charging system. It has been shown that the burden calculation model has resulted into reducing the variability in slag basicity, MgO and Al2O3 values.

Charging System Enhancements for a Blast Furnace at Azovstal Iron and Steel Works Private Joint-Stock Corporation

We discuss various charging systems for blast-furnace operations with and without injection of pulverized coal fuel (PCF) into the hearth. We also perform a mathematical simulation of the radial distribution of coke in ore charges and analyze production data on the variation in furnace-gas temperature at the burden surface across the top throat in different charging systems. An efficient blast-furnace charging system has been developed for use when pulverized coal fuel is injected into the hearth.

Results from the continuous operation of a bell-less rotary charging apparatus on a blast furnace for 6.5 years

Results are reported from the industrial operation of a bell-less rotary charging apparatus (BRCA), developed by the company TOTEM, on blast furnace No. 2 at the JSPL plant of the Jindal Corporation in India over a period of 6.5 years. Use of the BRCA has demonstrated the great effectiveness of rotary blastfurnace charging, with the furnace having set Indian records for unit productivity (72–73 tons/m3 hearth) and coke rate (330–340 kg/ton pig iron) while smelting a high-alumina raw material with a PCF consumption of 175–185 kg/ton pig. The cost of maintenance of the BRCA is minimal, it mainly involving replacement of the original gas-sealing valves every two years. The high operational reliability of the charging apparatus is proven by the fact that no repairs or replacement of its main components have been needed on BF-2 at the JSPL plant for 6.5 years.

A new charging protocol for blast furnaces

After tests at OAO Chelyabinskii Metallurgicheskii Kombinat, a new protocol has been introduced for blast-furnace charging. The proposed cycle consists of several mixed deliveries (ore + coke) and finally the delivery of several charging ladles with a single type of coke. This protocol has now been introduced at all three blast furnaces, with decrease in coke consumption and increase in furnace productivity.

Development of particle flow simulator in charging process of blast furnace by discrete element method

The objective of this paper is the development of a particle flow simulator for a blast furnace charging process using the discrete element method. A full model of the bell-less type charging process; i.e. a surge hopper, conveyors, a parallel hopper, a rotating chute and top layer of blast furnace, was modeled. The history of particle segregation during charging/discharging can be considered using this model. The particle segregation not only spatially-distributed but also temporal-distributed in each process can be analyzed in detail. The larger particles are stayed near the side walls due to segregation during flowing on the heap, when the particles are charged into the surge hopper or the parallel hopper. The segregation during flowing in the chute, which is installed above the parallel hopper, also affects segregation in the hopper. The larger particles tend to be discharged last, because they are near the side wall in the surge hopper or the parallel ones. The particles flow toward the center of the blast furnace with increasing the number of chute rotations, and are segregated during flowing. Thus, the mean particle size nearer the center increases.

Selective Dispersion of Rejected Iron Ore Ultra Fines for Feed to Blast Furnace and Minimize Environmental Issues

Indian iron mines dumps huge quantity of ultra fines containing high gangue minerals resulting in loss of iron values and environmental issues. The major gangue minerals containing alumina, silica and phosphorous are the cause for contamination of Indian iron ore. It has, therefore, become an urgent need to utilize these off-grade ultra fines after making it suitable for blast furnace charging. Due to the fine nature of these ultra fines, selective dispersion studies have been thought of. Two types of dispersants (i) inorganic, sodium hexametaphosphate and (ii) organic, sodium salt of poly acrylic acid have been tried. The performance of these two types of dispersions has been evaluated in separation process. Sodium salts of poly acrylic acid shows better separation of alumino silicate minerals in the ultra fines whereas, sodium hexametaphosphate efficiently separates out silica from the iron bearing minerals.

Optimal blast-furnace charging system

A new blast-furnace charging system ensures more uniform azimuthal distribution and optimally nonuniform radial distribution of the batch and gas. The coke consumption is reduced by 20–30 kg/t of hot metal, with 2% increase in output. The new design should recoup its cost within a year.

Blast-furnace charging with a lobed batch distributor

Blast-furnace charging with a lobed batch distributor

Blast-furnace charging system

Heretofore, iron blast-furnaces have incorporated an upper, material-receiving and distributing-hopper, its companion conical bell intermittently closing and opening the bottom of such hopper, automatic means to actuate such bell, a lower larger discharge-hopper at the top of the furnace adapted...

Mathematical Model of Gas Flow Distribution in a Scale Model of a Blast Furnace Shaft

The mutual influence between gas flow and burden distribution in the upper part of a blast furnace has been studied employing a simplified mathematical model to estimate burden distribution and a gas flow model based on Ergun's equation. Experiments carried out on a 1/10 scale cold model of Aceralia's blast furnace B were compared with results obtained from these mathematical models. Results corroborate that changes in burden distribution during the charging process have a strong influence on gas distribution, which also affects the burden layer profiles. These interrelations should be taken into account when the blast furnace charging patterns are designed

Method of reducing gaseous emissions from the large hopper of a blast-furnace charging apparatus

Method of reducing gaseous emissions from the large hopper of a blast-furnace charging apparatus

Diamond grinding of hard-faced contact surfaces of parts of blast-furnace charging apparatuses

Diamond grinding of hard-faced contact surfaces of parts of blast-furnace charging apparatuses

Analysis of the capacity of blast-furnace charging systems

Analysis of the capacity of blast-furnace charging systems