Search Results (111)

Particle-scale analysis of blast furnace burden surfaces lacks an operational criterion for separating long-scale shape from short-scale texture on complex digital elevation models. This study proposes a prior-informed framework in which the application cutoff ${\omega }^{*}=\arg \min J$ minimizes the mismatch between high-pass texture RMS height and the tiled-surface prior of the same particle batch. On cold-state large-coke belts with identical particles but different long-scale morphology, numerical validation via RMS–frequency transition analysis shows coincident transition structures. At a transition-informed validation cutoff of $\omega =4.2$, absolute texture errors of 1.56–3.22 mm are comparable in magnitude to the approximately 2 mm instrument depth resolution. Grid-search application yields ${\omega }^{*}=5.8$ and $4.4$ with absolute errors of 0.03 and 0.35 mm and operationally distinct shape and texture components. The separated fields can supply bed-surface boundaries and local roughness inputs for gas–solid simulation and charging optimization. Full article

In this study, the thermodynamic conditions governing TiC formation were systematically investigated based on Gibbs free energy and interaction parameter theory. The effects of temperature and furnace atmosphere on interaction parameters were explicitly incorporated, enabling an improved thermodynamic description of TiC formation under realistic blast furnace conditions. Furthermore, compared with conventional two-dimensional equilibrium analyses, a three-dimensional Ti-C-temperature thermodynamic precipitation surface was established to quantitatively evaluate the effects of temperature, titanium content, and carbon content on TiC precipitation behavior. The results indicate that titanium is the dominant controlling factor for TiC formation, while carbon plays a secondary synergistic role. Compared with dissolved carbon, solid carbon provides more favorable thermodynamic conditions, suggesting that TiC preferentially forms via interactions with high-activity carbon sources such as coke or refractory materials. Based on the modified thermodynamic framework and boundary conditions, a quantitative precipitation criterion was established as 100 × w[Ti]_% + w[C]_% ≥ 10, which ensures TiC precipitation prior to molten iron solidification under representative blast furnace hearth conditions. The proposed criterion provides a practical guideline for titanium addition and carbon regulation in blast furnace ironmaking and improves the thermodynamic prediction capability for titanium-bearing protective phase formation in complex high-temperature metallurgical environments. Full article

To achieve carbon emission reduction in the long ironmaking process with blast furnace-basic oxygen furnace (BF-BOF), the Hebei Iron & Steel Group and Northeastern University have jointly developed the Reduction Smelting Furnace with Carbon-Cycling, Hydrogen-Rich, and Pure-Oxygen (CHORSF) ironmaking process. This new process employs advanced technology to overcome the hydrogen enrichment limitation of traditional BFs and the problems of “hot at the lower part and cold at the upper part” in all-oxygen BFs. This paper establishes an operating line for the CHORSF ironmaking process, systematically analyzes the influence mechanisms of key smelting parameters on CHORSF, and provides guidance for optimizing the process. The results show that the slopes of the operating lines in the indirect reduction zone can characterize the reducing gas consumption under actual conditions; under the smelting conditions of this study, the reducing gas consumption falls within a specific range. The slope of the operating line in the softening–melting–dripping zone can be used to quantify the coke ratio. Furthermore, increasing the metallization ratio at the bottom of the indirect reduction zone leads to a slight increase in reducing gas consumption, while a 1% increase in the same metallization ratio results in a notable decrease in the coke ratio. Full article

The taphole is the only visible window for observing the blast furnace hearth state, and hot metal flow carries key hearth information. To address the problems of current hot metal flow monitoring, such as reliance on manual work, difficulty in quantification, poor real-time performance, as well as insufficient perception stability and low data utilization in existing research, this study proposes a full-chain intelligent solution for blast furnace taphole hot metal flow monitoring: by building an image acquisition system adapted to extreme working conditions, selecting ResNet50 as the state perception model, and combining Canny edge detection with the local morphological extremum analysis algorithm to extract core contour parameters; supplemented by the anti-vibration self-adjustment algorithm and the multi-taphole automatic switching strategy, the robustness and operation efficiency of the system are significantly improved. On this basis, a coke sticking early-warning model is constructed, splashing in different periods is quantitatively classified, and the spatiotemporal difference in hot metal flow is revealed. Finally, a full-chain technical system of “data acquisition–intelligent perception–working condition diagnosis–decision support” is formed, which promotes the digital and intelligent upgrading of hot metal flow monitoring and provides solid support for the safe operation. Full article

The operation of the gas–steam–electricity multi-energy coupling system in iron and steel enterprises faces critical challenges: conflicts between energy efficiency and economic objectives, insufficient scheduling accuracy, and low energy utilization caused by source–load fluctuations. To address these issues, this paper proposes a hybrid scheduling model based on condition awareness and multi-objective optimization. The model integrates three key components. First, an energy fluctuation prediction technology based on working condition changes is developed. By acquiring real-time production signals and gas flow data, combined with a condition definition management module, it enables automatic identification and tracking of equipment operation status. A working condition sample curve superposition method is used to calculate energy medium imbalances, generating visual prediction curves for key parameters such as blast furnace, coke oven, and converter gas holder levels, achieving an average prediction accuracy of ≥95%. Second, a peak-shifting and valley-filling scheduling model for gas holders is designed, leveraging time-of-use electricity prices. During valley price periods, power purchases are increased and surplus gas is stored; during peak price periods, gas power generation is increased to reduce purchased electricity. A nonlinear model capturing the load–efficiency relationship of boilers and generators is established to dynamically optimize scheduling strategies. This reduces the proportion of peak hour power purchases by 10.3%, energy costs by 3.12%, and system energy consumption by 2.16%. Third, a multi-period and multi-medium energy optimization scheduling model is formulated as a mixed-integer nonlinear programming (MINLP) problem, with dual objectives of minimizing operating cost and energy consumption. Constraints include energy supply–demand balance, equipment operating limits, gas holder capacity, and generator ramp rates. The Pareto optimal solution set is obtained using the AUGMECON2 method and efficiently computed with the IPOPT solver. Application results demonstrate that the model achieves zero gas emissions, a dispatching instruction accuracy of 95%, and a 0.8% increase in the proportion of peak–valley-level self-generated power, outperforming comparable technologies. It provides technical support for the safe, efficient, and economic operation of multi-energy systems in iron and steel enterprises. Full article

The COREX smelting-reduction route is a representative non-blast furnace technology, but its scale-up is hindered by insufficient gas and liquid permeability in the melter gasifier. To improve the gas and liquid permeability of the melter gasifier, coke is charged together with an iron-bearing material to partly replace lump coal to increase the burden voidage. The charged coke undergoes successive physical and chemical attacks that progressively weaken its strength, finally reducing the coke particle size and impairing overall burden permeability. Drilling “in situ” coke samples from the tuyere zone is an effective method to study coke behaviors inside a working melter gasifier. This work obtained tuyere coke samples by direct coke sample drilling during a melter gasifier blow-out and then systematically investigated the coke deterioration behaviors in the melter gasifier. The results show that the mean particle size decreased from an initial 50.3 mm to 31.6 mm at the tuyere, evidencing the severe fragmentation of coke. Basic oxides and alkali metals in the coke ash increased, indicating alkali recycling and enrichment occurred in the melter gasifier. Microcrystalline structure analysis of coke revealed a high degree of graphitization. Furthermore, coke degradation was further accelerated by both alkalis trapped in the coke pores and slag infiltration into the pores. This study clarifies the properties of the coke in the tuyere of the COREX melter gasifier and provides a theoretical basis for its operational optimization. Full article

Hydrogen-rich gas (HRG) injection is a promising low-carbon solution for blast furnace ironmaking. This study conducted numerical simulations in the lower part of a blast furnace to analyze the combustion behavior of coinjected coke oven gas (COG) and pulverized coal (PC) within the raceway and the associated thermal load on the tuyere. A three-dimensional computational fluid dynamics model incorporating fluid–thermal–solid coupling and the GRI-Mech 3.0 chemical kinetic mechanism (validated for 300–2500 K) was established to simulate the lance–blowpipe–tuyere–raceway region. The simulation results revealed that moderate COG injection accelerated volatile release from PC and enlarged the high-temperature zone (>2000 K). However, excessive COG injection intensified oxygen competition and shortened the residence time of PC, ultimately decreasing the burnout rate. Notably, although COG has high reactivity, its injection did not cause an increase in tuyere temperature. By contrast, the presence of an unburned gas layer near the upper wall of the tuyere and the existence of a strong convective cooling effect contributed to a reduction in tuyere temperature. An optimized cooling water channel was designed to enhance flow distribution and effectively suppress localized overheating. The findings of this study offer valuable technical insights for ensuring safe COG injection and advancing low-carbon steelmaking practices. Full article

This study evaluates coke for iron ore sintering manufactured from Ekibastuz coal fines (fraction 0–3 mm), spent anode material (SAM) from aluminum electrolysis, and coal tar pitch. Laboratory coking was performed at 1000 °C (60 min hold), followed by sintering trials using coke containing 10 wt% and 20 wt% SAM. Microstructural (SEM/EDS) and spectral data indicate an optimal SAM range of 10–20 wt%: higher additions (≥30 wt%) lead to structural degradation of coke, accompanied by reduced mechanical integrity. The produced coke shows C = 85%, S = 0.9–1.1%, ash ≈ 19%, volatiles = 1.5–2.5%, and moisture (Wr) ≤ 1%, which is acceptable for sintering use. In sintering tests, the yield of usable sinter reached 72.4% (10 wt% SAM) and 73.5% (20 wt% SAM); impact strength was 83% and 78%, respectively. XRF of sinter showed Fe_total > 51%, CaO ≈ 5.5–6.8%, SiO₂ ≈ 6.6–7.2%, and S = 0.40–0.45%, meeting technological requirements for blast-furnace practice. Overall, using spent anode material within 10–20 wt% increases fixed-carbon content, enables valorization of aluminum industry waste, and delivers coke for agglomeration performance without compromising key chemical or mechanical indices. Full article

Coke is an essential raw material in the blast furnace (BF) ironmaking process. Its moisture content significantly impacts BF ironmaking production. This study employs a coupled Computational Fluid Dynamics–Discrete Element Method (CFD-DEM) approach to simulate the drying process of wet coke within a coke silo (CS) dryer. Initially, the model was validated by comparing numerical results with experimental data from the literature. Subsequently, it investigated the gas flow dynamics, heat and mass transfer characteristics, and differences in drying behaviour across distinct dryer zones. Finally, the effects of inlet gas velocity and inlet gas temperature on the drying process were systematically quantified. Simulation results reveal that the bottom of the CS dryer exhibits a low-velocity laminar state, while the middle and upper regions display intense gas flow motion. Consequently, the bottom region exhibits insufficient particle drying in comparison to other zones, with the average particle moisture content decreasing by less than 20%. Under the continuous heat exchange between the hot gas and the particles, the moisture content of the particles decreases rapidly. Based on the drying rate behaviour, the drying process exhibits the following three different stages: the pre-heating period, the constant-rate period, and the falling-rate period. Compared to zones 1 and 3, zone 2 exhibits higher temperatures due to its high heat transfer efficiency, which significantly promotes a reduction in particle moisture content. An increase in inlet gas velocity enhances the particle drying rate and heat flux, accelerates moisture reduction, and raises the temperature. The impact of inlet gas velocity is most pronounced after the constant-rate period, with particle drying uniformity decreasing as the inlet gas velocity increases, consequently leading to a decline in drying quality. Increasing inlet gas temperature significantly increases particle temperature and heat flux throughout the drying period and accelerates the high-rate drying stage. These findings provide fundamental insights for further understanding and studying the coke drying process. Full article

The oxygen blast furnace (OBF) is a promising technology for ironmaking, and its burden distribution pattern plays a key role in optimizing performance. This study investigates the impact of the peripheral opening extent (POE), which reflects the coke distribution adjacent to the furnace wall, on OBF performance using a computational fluid dynamics (CFD) process model. A 380 m³ OBF is simulated, incorporating reducing gas injection through both the hearth tuyeres and shaft tuyeres. By analyzing the inner states, the global performance is evaluated. The results show that the optimal POE value is 20°, which minimizes the fuel rate, maximizes productivity, and achieves the highest top gas utilization factor. As POE increases, chemical reaction carbon consumption decreases. The combustion heat in front of the tuyeres initially decreases and then increases, leading to a corresponding decrease and subsequent increase in carbon consumption in the tuyeres. The combined effects of these factors cause the fuel rate to first decrease and then increase. Additionally, this study quantifies the relationship between shaft injection rate and burden distribution. It is found that shaft injection improves the furnace’s thermal state and enhances the reducing atmosphere, leading to a reduced fuel rate. Notably, the optimal POE value remains constant at 20°, regardless of the shaft injection rate, suggesting that POE selection is independent of the injection rate. Overall, appropriate peripheral openings contribute to improving OBF global performance. These findings should be helpful to the industrial OBF operation. Full article

The civil construction and infrastructure sectors are known for their high environmental impact. Most of this impact is related to the carbon dioxide (CO₂) emissions from Portland cement. As a sustainable alternative, alkali-activated binders (AABs) are explored for their potential to replace traditional binders. This research focused on AAB formulations using steel industry byproducts, such as Baosteel’s slag short flow (BSSF), coke oven ash (CA), blast furnace sludge (BFS), and centrifuge sludge (CS), as well as fly ash (FA) from a thermoelectric plant. Byproducts were characterized through laser granulometry, Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscopy (SEM), followed by the formulation of AABs with different precursor ratios. After 28 days, the compressive strength was obtained for each formulation. Based on the compressive strength tests, two binary mixtures were selected for microstructural and chemical analyses through XRF, FTIR, and SEM. CA demonstrated the greatest potential for use in binary AABs based on BSSF, as it presented a higher source of aluminosilicates and smaller particle sizes. The formulations containing BSSF and CA achieved compressive strengths of up to 9.8 MPa, while the formulations with BSSF and FA reached 23.5 MPa. SEM images revealed a denser, more cohesive matrix in the FA-based AAB, whereas CA-based AABs showed incomplete precursor dissolution and higher porosity, which contributed to the lower mechanical strength of CA-based AABs. These findings highlight the critical role of precursor selection in developing sustainable AABs from industrial byproducts and demonstrate how different formulations can be tailored for specific applications. Full article

The blast furnace (BF) and basic oxygen route account for approximately 70% of the global steel production and create 1.8 tons of CO₂ per ton of steel, produced primarily due to the use of coke and pulverized coal (PC) at the BF. With global pressure to reduce CO₂ emissions, optimization of BF operation is crucial, which is possible through optimizing fuel consumption, and improving process stability. Understanding the complex combustion and flow dynamics in the raceway region is essential for enhancing reducing agent utilization. Modeling plays a key role in predicting these behaviors and providing insights into the process; however, validation of these models is crucial for their reliability but difficult in the complex and hostile BF raceway region. In this study, a validated raceway model developed at Swerim was used to evaluate four different cases, namely R1 (Reference), R2 (Low oxygen to blast), R3 (High blast moisture), and R4 (High PC) using an injection coal from SSAB Oxelösund. During actual experiments, the temperature distribution in the raceway was measured using a thermovision camera (TVC) to validate the CFD simulation results. The combined use aims to cross-validate the results simultaneously to establish a reliable framework for future parametric studies of raceway behavior under varying operational conditions using CFD simulations The results indicated that it is possible to measure the temperature within the raceway region using TVC at depths indicated to be 0.5–0.7 m, when not obscured by the coal plume, or <0.5 m, when obscured. TVC measurements are clearly quantitatively affected when obscured, indicated by considerably lower temperatures in the order of 200 °C between similar process conditions. A decrease of O₂ injection results in an extended raceway region as the conditions become less chemically favorable for combustion due to a lower reactant content offsetting the ignition point and reducing the reaction rate in the raceway. An increased moisture content in the blast results in a reduced size of the race-way region as energy is consumed as latent energy and cracks water. An increase in PC rate results in a larger/wider raceway region, as more PC is devolatilized and combusted early on, resulting in larger gas volumes expanding the raceway region outwards, perpendicular to the injection. Full article

The conceptual design and techno-economic assessment of Pressure Swing Adsorption (PSA) for the recovery of H₂, CO₂, and CO from steel making Blast Furnace-Basic Oxygen Furnace and Coke Oven off-gases, major contributors to anthropogenic carbon emissions, are presented. Three PSA units are modeled on Aspen Adsorption V14, each utilising dedicated adsorbents and configurations tailored for the target gas. Model validation is successfully conducted by comparing breakthrough simulation results with experimental data. The simulation results demonstrate that the PSA systems effectively separate H₂ (99.3% purity, 80% recovery), CO (98% purity, 87% recovery), and CO₂ (96.9% purity, 75% recovery) from steelmaking off-gases. Meanwhile, the techno-economic assessment indicates that the PSA systems are economically viable, with competitive costs of £2768/tH₂, £52.78/tCO, and £16.89/tCO₂ captured, making them an effective solution for gas separation in the steel industry. Full article

The coke and ore are stacked alternately in layers inside the blast furnace. The capability of the charging system to distribute them in the desired manner and with optimum strata thickness is crucial for the efficiency and high-performance operation of the blast furnace itself. The objective of this work is the optimization of the charging equipment of a specific blast furnace. This blast furnace consists of a hopper, a single bell and a deflector inserted in the hopper under the conveyor belt. The focus is the search for a deflector geometry capable of distributing the material as evenly as possible in the hopper in order to ensure the effective disposal of the material released in the blast furnace. This search was performed by coupling the discrete element method with a multi-strategy and self-adapting optimization algorithm. The numerical results were qualitatively validated with a laboratory-scale model. Low cost and the simplicity of operation and maintenance are the strengths of the proposed charging system. Moreover, the methodological approach can be extended to other applications and contexts, such as chemical, pharmaceutical and food processing industries. This is especially true when complex material release conditions necessitate achieving bulk material distribution requirements in containers, silos, hoppers or similar components. Full article

The iron and steel industry, as a major energy consumer, was critically required to enhance operational efficiency and reduce CO₂ emissions. Conventional blast furnace processing of vanadium–titanium magnetite (VTM) in China had been associated with persistent challenges, including suboptimal TiO₂ recovery rates (<50%) and elevated carbon intensity (the optimal temperature range for TiO₂ recovery lies within 1400–1500 °C). Shaft furnace technology has emerged as a low-carbon alternative, offering accelerated reduction kinetics, operational flexibility, and reduced environmental impact. This study evaluated the low-carbon PLCsmelt process for VTM smelting through energy–mass balance modeling, comparing two gas-recycling configurations. The process integrates a pre-reduction shaft furnace and a melting furnace, where oxidized pellets are initially reduced to direct reduced iron (DRI) before being smelted into hot metal. In Route 1, CO₂ emissions of 472.59 Nm³/tHM were generated by pre-reduction gas (1600 Nm³/tHM, 64.73% CO, and 27.17% CO₂) and melting furnace top gas (93.98% CO). Route 2 incorporated hydrogen-rich gas through the blending of coke oven gas with recycled streams, achieving a 56.8% reduction in CO₂ emissions (204.20 Nm³/tHM) and altering the pre-reduction top gas composition to 24.88% CO and 40.30% H₂. Elevating the pre-reduction gas flow in Route 2 resulted in increased CO concentrations in the reducing gas (34.56% to 37.47%) and top gas (21.89% to 26.49%), while gas distribution rebalancing reduced melting furnace top gas flow from 261.03 to 221.93 Nm³/tHM. The results demonstrated that the PLCsmelt process significantly lowered carbon emissions without compromising metallurgical efficiency (CO₂ decreased about 74.48% compared with traditional blast furnace which was 800 Nm³/tHM), offering a viable pathway for sustainable VTM utilization. Full article