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As the iron and steel industry needs to cut its CO2 emissions drastically, much effort has been put into establishing new—less greenhouse-gas-intensive—production lines fueled by hydrogen and electricity. Blast furnaces, as a central element of hot iron production, are expected to lose importance, at least in European production strategies. Yet, blast furnaces could play a significant role in the transitional phase, as they allow for the implementation of another CO2-reducing fuel, carbonized wood reducing agents, as a substitute for coal in auxiliary injection systems, which are currently widely used. Wood carbonization yields vastly differing fuel types depending on the severity of the treatment process, mainly its peak temperature. The goal of this study is to define the lowest treatment temperature, i.e., torrefaction temperature, which results in a biogenic reducing agent readily employable in existing coal injection systems, focusing on their conveying properties. Samples of different treatment temperatures ranging from 285 to 340 °C were produced and compared to injection coal regarding their chemical and mechanical properties. The critical conveyability in a standard dense-phase pneumatic conveying system was demonstrated with a sample of pilot-scale high-temperature torrefaction. [ABSTRACT FROM AUTHOR]

The conditions in the combustion zones, i.e., the raceways, are crucial for the operation of the blast furnace. In recent years, advancements in tuyere cameras and image processing and interpretation techniques have provided a better means by which to obtain information from this region of the furnace. In this study, a comprehensive approach is proposed to visually monitor the status of the pulverized coal cloud at the tuyeres based on a carefully designed processing strategy. Firstly, tuyere images are preprocessed to remove noise and enhance image quality, applying the adaptive Otsu algorithm to detect the edges of the coal cloud, enabling precise delineation of the pulverized coal region. Next, a Swin–Unet model, which combines the strengths of Swin Transformer and U-Net architecture, is employed for accurate segmentation of the coal cloud area. The extracted pulverized coal cloud features are analyzed using RGB super-pixel weighting, which takes into account the variations in color within the cloud region. It is demonstrated that the pulverized coal injection rate shows a correlation with the state of the cloud detected based on the images. The effectiveness of this visual monitoring method is validated using real-world data obtained from a blast furnace of SSAB Europe. The experimental results align with earlier research findings and practical operational experience. [ABSTRACT FROM AUTHOR]

In this study, the feasibility indicators of the injection of coke breeze for blast furnaces (BFs) were tested. Experiments were conducted on the combustion behavior of coke breeze at different particle sizes, and the effects of ratio of coke breeze in pulverized coal on the combustion performance of blends were studied. On the basis of the above experiments, industrial tests involving injecting coke breeze after milling were carried out in 3# BF of Shougang Jingtang. The results show that most of the coke breeze particle sizes were distributed above 1 mm. The grindability and combustion performance are poor, so the material needs to be ground before mixing with pulverized coal. The best combustibility can be obtained by using a particle size of less than 8.74 μm of coke breeze in the injection. With the increase in the coke breeze ratio, the combustion performance of blended coal worsened; the negative effects of coke breeze can be improved by increasing the proportion of bituminous coal. According to the results of industrial tests, 8% coke breeze in blends had no negative effect on the smelting state, and the output of the BF increased slightly. Industrial tests proved that coke breeze can partly replace anthracite for BF injecting, which reduced the cost of hot metal while realizing the high value-added resource utilization of coke breeze. [ABSTRACT FROM AUTHOR]

Pulverized coal injection technology plays a crucial role in controlling the blast furnace process but increasing the combustion efficiency of coal remains a challenge. Towards this, the manuscript attempts to examine the performance of different coals subjected to different operating and geometric parameters through a validated numerical model. Two coals with different volatile matter have been selected for this study while oxygen enrichment, lance position, and particle size distribution have been varied. Among all parameters, particle fineness has proven to be the major contributor towards improving burnout. The underlying mechanism has been explained in terms of oxygen distribution and particle temperature. In addition, the combined effect of all parameters increases the final conversion by 6% and 10% for high and low volatile coals respectively. Ease of volatile release plays an important role in controlling the overall burnout where a higher release rate for high volatile coal somewhat compensates for the impact of the parameters studied. [ABSTRACT FROM AUTHOR]

Summary: The blast furnace ironmaking process is one of the most energy‐consuming processes, and proper operation of pulverized coal injection (PCI) technique, applied in the blowpipe of hot blast air, can significantly reduce the CO2 emissions. Therefore, this study focuses on the conveying solid‐gas ratio (SGR) and ways of oxygen enrichment in a PCI system using a lance‐blowpipe‐tuyere‐raceway model. It is found that an optimal value of SGR could be obtained under two competing effects: the dispersion of pulverized coal and the cooling effect of carrier gas. When oxygen is enriched by 4%, the coal‐burnout rate can be enhanced by 5% to 6% via hot blast and 9% to 11% through oxy‐coal lance injection at SGR = 10 to 50. Moreover, the highest burnout rates in single lance and oxy‐coal lance injections occur respectively at SGR = 40 and 45. For the case of the oxy‐coal lance, the pressure loss is relatively smaller because it ignites farther away from the blast mouth. As a result, this improves the permeability of blast flow at the bottom of the furnace. In addition, the numerical results also show that the swirl‐flow design for pure oxygen injection through the oxy‐coal lance does not significantly improve coal combustion. [ABSTRACT FROM AUTHOR]

Accurate detection for pulverized coal injection (PCI) blockage and coke size distribution are effective for blast furnace (BF) operation. Nowadays, tuyere cameras have been applied in BF. However, the appearance of captured raceway images changes, which requests the detection method to be adaptive. Therefore, an intelligent detection method for PCI blockage and coke size distribution is proposed. An adaptive pre-processing algorithm is firstly developed to improve image quality. Secondly, the fitting circle is used to locate tuyere region and the improved U-net network is investigated for lance segmentation to construct the background template. Then, target regions can be obtained by background subtraction algorithm. Finally, the PCI blockage can be detected according to the area information, and the size distribution of cokes can be calculated by multi-directional Feret diameter. Massive raceway videos are used to evaluate the method. Experiment results show the method can detect PCI blockage and cokes size distribution. [ABSTRACT FROM AUTHOR]

• A novel CFD-DEM-DPM model is developed to describe the FPF reacting flows. • It is applied to model the co-combustion of coke particles and coal fines in a practical BF. • A dynamic raceway cavity driven by fluid-particle-fine interactions is predicted explicitly. • The model provides a cost-effective tool for understanding FPF-related processes. The complex fluid-particle-fine (FPf) reacting flows have been widely practised in many energy-intensive engineering processes, yet numerical methods capable of comprehensively describing the particle-scale thermochemical behaviours related to the FPf reacting flows were still lacking. In this work, a novel CFD-DEM-DPM model is developed, for the first time, to describe the fluid, particles and fines reacting flows and their interactions. Then, to demonstrate its effectiveness, it is employed to simulate the co-combustion of coke and pulverized coal in a dynamic raceway in ironmaking blast furnaces (BFs). After model validation, the complex in-furnace phenomena related to the co-combustion of coarse coke particles and fine coal particles are comprehensively captured. Particularly, instead of the pre-set raceway treatment in the previous raceway simulations, a dynamic raceway cavity is predicted explicitly driven by the fluid-particle-fine interactions and further, inside the dynamic raceway, the combustion of coal fines including moisture evaporation, devolatilization and char reactions are presented in detail. Subsequently, the impact of operations with and without coal injections are quantitatively compared, showing that both the reducing gas and reaction heat from the coal combustion contribute to an expansion of the raceway cavity. Further, the effects of pulverized coal rate on the in-furnace phenomena are studied. The present work represents a significant breakthrough in the explicit modelling of FPf reacting flows, and provides a cost-effective tool for understanding FPf-related processes and developing new technologies including carbon–neutral ironmaking technologies. [ABSTRACT FROM AUTHOR]

The blast furnace gas separated by a membrane has a higher content of combustible components. In order to explore its secondary utilization in blast furnace production, numerical simulation is conducted by means of Fluent software, and the model is verified by experimental data. Results show that when the blast furnace gas separated by the membrane is used as pulverized coal carrier gas for blast furnace injection, the gas velocity in the furnace evidently increases, and the maximum injection velocity can reach 279 m s−1. The formed high-temperature zone is closer to the centre of the blast furnace than those in the single injection of pulverized coal and in pulverized coal injection with general blast furnace gas as a carrier gas. The maximum temperature reaches 2610 K. Moreover, the pyrolysis reaction of pulverized coal is in advance, whereas the burnout rate of pulverized coal in the raceway presents a double-peak phenomenon. [ABSTRACT FROM AUTHOR]

Mathematical models appear as very attractive alternatives in blast furnace studies. Therefore, a three-dimensional model is described and validated to simulate the flow and combustion of binary coal blends under simplified blast furnace conditions. The present article aims to analyse the performance of different coals and their blends for conventional and coaxial oxygen enrichment methods. Among the simulated coals, Coal C, which combines one of the smallest particle sizes with one of the highest volatile matter contents, presented the highest burnout and average temperature values. Coaxial oxygen enrichment showed a negative effect on coal combustibility in the cases with 26.9% of O2. This is explained by the large amount of gas being injected by the coaxial lance, resulting in a cooling effect and particle concentration. Also, blending coal A with coal B resulted in an improvement of burnout for both coals, because of the synergetic effect caused by their combustion. [ABSTRACT FROM AUTHOR]

This work investigates the effects of carbon allocation on the emission intensities of low-carbon products cogenerated in facilities that co‐process biogenic and fossil feedstocks and apply the carbon capture utilization and storage technology. Thus, these plants simultaneously sequester CO2 and synthesize fuels or chemicals. We consider an integrated steel mill that injects biomass into the blast furnace, captures CO2 for storage, and ferments CO into ethanol from the blast furnace gas. We examine two schemes to allocate the CO2 emissions avoided [due to the renewable feedstock share (biomass) and CO2 capture and storage (CCS)] to the products of steel, ethanol, and electricity (generated through the combustion of steel mill waste gases): 1) allocation by (carbon) mass, which represents actual carbon flows, and 2) a free-choice attribution that maximizes the renewable content allocated to electricity and ethanol. With respect to the chosen assumptions on process performance and heat integration, we find that allocation by mass favors steel and is unlikely to yield an ethanol product that fulfills the Renewable Energy Directive (RED) biofuel criterion (65% emission reduction relative to a fossil comparator), even when using renewable electricity and applying CCS to the blast furnace gas prior to CO conversion into ethanol and electricity. In contrast, attribution fulfills the criterion and yields bioethanol for electricity grid intensities

The actual combustion rate of pulverized coal in the blast furnace tuyere is hard to be measured. In this research, the combustion rate of pulverized coal injected into oxygen blast furnace was obtained by a new equipment. This equipment can simulate the actual blast furnace well, and the relationship between pulverized coal injection (PCI) ratio and AO/C was established by mathematical deduction. The experimental results show that the best combustibility of the four pulverized coals is C, and when the coal injection ratio is 350 kg/tHM, the combustion rate can be reached 79%, while the combustion rate of B in the same case is only 45.6%. With the increase of AO/C, the relative amount of oxygen to coal increases, the combustion conditions become better, and combustion rate of the pulverized coal increases. In addition, under the condition of high temperature and rapid combustion, with the increase of coal’s volatile, the combustion rate increases and the corresponding PCI ratio is also increased. By using the new equipment, the unburned coal under the oxygen blast furnace conditions can be collected for further study.

Combustion process of bituminous coal, steam coal, anthracite (AC) and semi-coke were investigated through thermogravimetric analysis method and influence of metamorphic grade as well as heating rate on combustion characteristics were analyzed. Results show that combustion performance could not be represented by single combustion characteristic parameter. Through analysis of comprehensive combustion characteristic indexes, with increase of metamorphic grade combustion performance of coal is lowered, and combustion performance of semi-coke and AC are close to each other. With increase of heating rate, combustion curves move into high temperature region and comprehensive combustion characteristic indexes are increased, which show that the combustion performance is improved. Random pore model (RPM), unreacted shrinking core model (URCM) and volume model were used to calculate kinetic parameters of combustion process. Results show that RPM has the best performance to represent combustion process of the four samples and through calculation by RPM kinetic energy of combustion process for all samples are between 43.08 and 99.43 kJ/mol, and there is compensation effect during combustion process.

The pulverized coal injection (PCI) is pursued to reduce the hot metal production cost by replacing the expensive metallurgical coke with the non-coking coal. Increasing the PCI rate causes various difficulties in the blast furnace (BF) operation. In the present work, an attempt is made to review the various aspects of PC injection in BF such as the challenges with increasing the PCI rate and modifications in the injection system to circumvent the concerns related to higher PCI rate. Various methods for detecting the tuyere blockage and failure caused due to the high PCI rate are elaborated. The factors influencing the combustion of coal in front of tuyeres have been discussed and their impact in the replacement ratio has been discussed. Further, recommendations are made to improve the coal combustibility in front of tuyeres. [ABSTRACT FROM AUTHOR]

• The effect of flux on the combustion behavior of coal is studied. • The actual operating conditions of blast furnace is converted to the experimental conditions. • Effect of co-injecting of fluxes and pulverized coal on smelting in blast furnace is studied. The integration of advanced high-ratio pellet ore smelting technology with flux injection at the blast furnace tuyere offers significant carbon emission and air pollution reductions for iron and steel manufacturers. This study presents a comprehensive thermogravimetric analysis and burnout rate assessment of Russian Bituminous Coal (RB) and flux mixtures across varying mass ratios, alongside a detailed exploration of the catalytic mechanisms of three distinct fluxes on RB combustion. The findings reveal that lime, when added to the coal-flux blend, markedly enhances the overall combustion characteristic index and catalytic impact, more so than limestone or dolomite. The optimal lime admixture of 5 % resulted in a peak S value of 6.30 and a burnout rate of 70.63 %, constituting an increase of 7.64 % over the base case without flux. Lime's superior catalytic performance is attributed to its higher content of calcium-containing compounds, which amplify catalytic activity through increased Ca2+ ion exchange with carboxyl groups. Mathematical model calculations considering the combustion rate of the pulverized coal show that: after the addition of 5 % lime, there is a 133.43 t/d increase in iron production, compared to the 11,323.98 t/d without the addition of flux. When the lime addition amount is 7 %, the proportion of sintered ore in the blast furnace decreases by 6.53 %, and the coke saving is 2.8 kg/t. This research is expected to enhance the understanding of pulverized coal combustion when amalgamated with basic fluxes and serve as a theoretical foundation for optimizing industrial applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ammonia addition for ironmaking is thermodynamically analyzed. • Ammonia addition with carbon and air subtraction can increase iron conversion. • Depending on addition method, ammonia can increase or decrease NO X or N 2 O emissions. • Ammonia addition reduces carbon dioxide emissions but also increases endothermic activity. • A neural network was developed to predict iron reduction characteristics and had an R2 of 0.99706. This study aimed to simulate the thermodynamics of ammonia addition to iron oxide reduction and to use the results of the thermodynamic analysis to develop a neural network that predicts iron oxide reduction performance from input parameters. The results showed that ammonia addition can increase iron (Fe) reduction when carbon and air are proportionally subtracted. However, iron oxide reduction assisted by ammonia is more endothermic, indicating ammonia may have insufficient exothermic activity to maintain the endothermic reduction of iron oxides. Additionally, the simulation suggests ammonia addition can limit the carbon dioxide (CO 2) produced by conventional iron oxide reduction using coke. Further, ammonia addition can reduce oxides of nitrogen (NO X) and nitrous oxide (N 2 O) emissions, depending on the addition method. A neural network was developed using one hidden layer with 10 neurons to predict the system enthalpy, the extent of iron oxide reduction, carbon dioxide production, NO X concentration, and CO concentration from the temperature, ammonia addition percent, and method of ammonia addition. After training for 43 epochs, the neural network achieved an R2 value of 0.9985. Although there are some limitations to the Gibbs minimization method employed in this study, the results indicate ammonia has the potential to supplement coke in ironmaking. More research is required to determine the extent ammonia could be employed to reduce greenhouse gas emissions from ironmaking processes. [ABSTRACT FROM AUTHOR]

It is expedient to modify blast furnace profiles so as to better suit new raw materials and fuel additives. Research shows that the shaft height may be increased and the cross section may be enlarged. It is clear from practical experience and the available data regarding the physical and chemical properties of batch components that the inclination of the shaft and the shoulders may be decreased when the batch consists entirely of pellets and pulverized coal injection is employed. With decrease in inclination of the shoulders to 76° at one blast furnace of Yenakiieve Iron and Steel Works, normal thermal conditions may be ensured in the section between the shoulders and the bottom of the shaft over a five-year run after startup. [ABSTRACT FROM AUTHOR]

Pulverized coal injection (PCI) is a technique worldwide used in blast furnaces (BFs) to reduce coke consumption. Burning of pulverized coal injected into tuyeres of BFs takes place under medium pressure (up to 450 kPa), high flame temperatures (around 2500 K), very fast heating rates (105-106 K/s) and very short residence times, less than 40 ms. Since there are no standard tests for evaluation of coal combustibility at PCI conditions, lab scale injection rigs are usually employed for this purpose. This work shows relevant characteristics of the injection rig developed by LASID-UFRGS, which operates at automated injection mode. The main rig features are direct measurement of pressure and temperature inside the combustion zone during combustion process, temperature measurement with ultra-fast thermocouples (ms), high speed control and data acquisition (ms) and collection of both solid and gaseous combustion products. First results showed pressure and temperature evolution along throughout the combustion test, with and without sample, combustion gas composition and coal burnout for different coals. Experimental data statistics showed good repeatability for all tested coals. [ABSTRACT FROM AUTHOR]

The effects of dust collection from steelmaking plants on the combustion characteristics of pulverized coal were investigated. Three influencing factors including the dust types, addition method, and addition amount of dust on the catalytic combustion were determined. Four types of basic oxygen furnace (BOF) dust can improve the combustion reactivity and combustion efficiency to different extents. The catalytic effects include that the ignition/burnout temperatures was decreased, and the maximum combustion rate and heat release were increased. A smaller particle size, larger BET surface, developed pore structure, and higher amount of CaO in BOF dust are beneficial for improving the catalytic effects on coal combustion. When increasing the addition amount, the catalytic effects on coal combustion first increased and then decreased with an optimum rust-to-coal ratio of 1:30. The addition methods have significant effects on catalytic combustion. The mixture prepared through grinding after blending showed better combustion reactivity than that prepared through blending only, and the suspension blending displayed was better than that of dry blending. The pollutant gas evolution including CO and SO 2 during coal combustion was suppressed by adding BOF dust, and the CO 2 evolution was promoted owing to the transformation of CO into CO 2 . [ABSTRACT FROM AUTHOR]

Victorian brown coal is a low-cost and abundant resource, featuring in high moisture and low ash yield, and has a potential of replacing high grade metallurgical coals in pulverized coal injection (PCI) in ironmaking blast furnace (BF). In this paper, a three-dimensional mathematical model is used to simulate the flow and thermochemical behaviours related to the PCI operation of upgraded Victorian brown coals under full-scale BF conditions. The model geometry covers lance, blowpipe, tuyere, raceway and coke bed at the lower part of a BF. The typical phenomena of in-furnace aerodynamics and physicochemical behaviours relevant to the injection of Victorian brown coals are simulated, in terms of flow, temperature, gas composition and coal combustion characteristics. It is indicated that the model is able to predict the combustion phenomena of Victorian brown coals under BF conditions. The performance between one typical PCI coal and two upgraded brown coals by briquetting and pyrolysis, respectively, are compared. The results indicate the upgraded Victorian brown coal by pyrolysis under given conditions has demonstrated the similar combustion profile with the PCI coal, confirming the feasibility of replacing PCI coal with an upgraded brown coal. Compared with the other two coals, briquetted brown coal of relatively higher volatile matter (VM) led to the release of more fuel gas, thus consuming more oxygen and achieving higher temperature along the tuyere axial and along the raceway boundary. Faster combustion of briquetted brown coal also led to higher overall burnout around the raceway region. The model provides a cost-effective tool to optimize and control the injection of Victoria brown coals under industry-scale BF conditions. [ABSTRACT FROM AUTHOR]

Some aspects of permeability deterioration in blast furnace process at high rates of pulverized coal injection are not well known yet. At operational practice variations in the ash quality of injected coals can affect the furnace performance. Previous work has investigated the behavior of individual coals ash at high temperatures in relation to the chemical and mineralogical compositions. This work aimed to assess this behavior for coal blends. Four coals and seven blends were selected and ashed at 800-850°C. The samples were analyzed by X-ray fluorescence and X-ray diffraction techniques and ASTM ash fusion (AFT) and viscosity tests were performed. Ash containing high contents of Si and Al showed higher fusion temperatures and higher viscosity at 1500°C, due mainly to the higher content of Mullite and to the low basicity, while those presenting significant contents of Fe, Ca and S had lower fusion temperatures and lower viscosity, due to the higher content of Anorthite and/or to the higher basicity.

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The steel industry has an important participation in the generation of greenhouse gases due to the high consumption of coal and coke in the energy balance. The pulverized coal injection in the blast furnace can be an alternative to reduce this effect by using biomass which are renewable source and through photosynthesis captures the CO2 gas from the atmosphere, reducing the pollution caused by the blast furnaces. The bark of eucalyptus is rich in carbon and complements the provision of that element to the process of iron ore reduction. This work aimed to study the bark of eucalyptus insert for injection in blast furnace tuyeres. To simulate the possibility of injection material, a physical modeling is used, which has been developed for this purpose. Other techniques are used to characterize the materials as size classification, combustion, calorimetry, gas analysis, immediate chemical and elemental analysis. So, in theory, this research attempts to shows that barks of eucalyptus can be injected into blast furnaces in place of the pulverized coal. [ABSTRACT FROM AUTHOR]

Pulverized Coal Injection (PCI) is an important standard technology replacing coke partially by pulverized coal into the blast furnace that allows a significant reduction of hot metal costs and environmental impact, contributing to a decrease of coke requirements for ironmaking. Coals typically used in this process in Brazil are, at current time, exclusively imported from many countries, although economic important coal-measures occur in the southern part of the country. The Brazilian coals have a low rank, higher contents of inert components, proportioning nocoking properties and an expected high reactivity. Due to these caractheristics, these coals could be used for injection in the blast furnaces in order to decrease the dependency on high cost imported coals. The efficiency in the combustion and the coal reactivity are considered important parameters in the blast furnace, since a larger amount of char (unburned coal) causes severe problems to the furnace operation. The aim of the present work is to compare the reactivity of a south Brazilian coal, obtained from Faxinal mine, with two imported coals and the blends of the Brazilian coal with the imported ones. The reactivity of these coals and their blends were evaluated in a thermogravimetric analyzer. In the experiments, various mass ratios of Faxinal coal and the imported coals were used to compose the blends. The gasification reaction with pure CO2 was conducted under isothermal conditions at 1050 °C and atmospheric pressure. The experimental results show the greater reactivity of the Faxinal coal. The additive behavior was confirmed. The blends with a composition of up to 50% Faxinal coal have parameters according to the usual limits used for PCI.

This paper analyses the applicability of well-known risk management methodologies in energy efficiency projects in the industry. The possibilities of application of the selected risk management methodology are demonstrated within the project of the plants for injecting pulverized coal into blast furnaces no. one and two, implemented by the company US Steel Serbia d.o.o. in Smederevo. The aim of the project was to increase energy efficiency through the reduction of the quantity of coke, whose production requires large amounts of energy, reduction of harmful exhaust emission, and increase productivity of blast furnaces through the reduction of production costs. The project was complex and had high costs, so that it was necessary to predict risk events and plan responses to identified risks at an early stage of implementation, in the course of the project design, in order to minimise losses and implement the project in accordance with the defined time and cost limitations. [ABSTRACT FROM AUTHOR]

The combustion process of pulverized coal injected into blast furnace involves a lot of physical and chemical reactions. Based on the combustion behaviors of pulverized coal, the conception of coal effective calorific value representing the actual thermal energy provided for blast furnace was proposed. A cost performance evaluation model of coal injection was built up for the optimal selection of various kinds of coal based on effective calorific value. The model contains two indicators: coal effective calorific value which has eight sub-indicators and coal injection cost which includes four sub-indicators. In addition, the calculation principle and application of cost performance evaluation model in a Chinese large-scale iron and steel company were comprehensively introduced. The evaluation results finally confirm that this novel model is of great significance to the optimal selection of blast furnace pulverized coal. [ABSTRACT FROM AUTHOR]

Currently the world is tending towards a dramatic specific consumption of coke per ton of pig iron by injection of coal dust in blast furnace tuyeres. The purpose of injecting pulverized coal in the furnace is to reduce coke consumption, to replace the liquid fuels and natural gas, to ensure a steady running, increase economic efficiency and improve environmental conditions. The injection of pulverized coal technology in the furnace is justified by: increase furnace productivity, expressed as the amount of iron produced per day in the furnace; reducing the consumption of more expensive coking coal and metallurgical coke, through replacing of coke with energetic coal; maintaining the stability of the furnace; improving the quality and reducing the silica content in iron cast without disturbance of the thermal regime of the furnace; reducing emissions of greenhouse gases. [ABSTRACT FROM AUTHOR]

In this research, coal combustion behavior across the regions of blowpipe, tuyere, and raceway of blast furnace are numerically examined. Three different lance configurations, including a single lance, a double air-cooled coaxial lance, and an oxy-coal lance with different oxygen enrichment patterns, are taken into consideration. The coal combustion efficiency by the double lance injection is 5.1% higher than that by single lance injection. From the calculated temperature by the oxy-coal lance, coal ignition is retarded due to the cooling effect of enriched oxygen flowing through the lance annulus, resulting in the moderation of pressure loss within the raceway. Most importantly, the enriched oxygen becomes the combustion enhancer in the downstream of coal plume after ignition is triggered. Consequently, the coal burnout under the oxy-coal lance injection is comparative to that under the double air-cooled lance injection. The performance of blast furnace may be improved with the advantages provided by the oxy-coal lance injection. Compared with the single lance injection, coal trajectories under the oxy-coal lance injection are closer to the tuyere exit due to the higher inertia force of coal particles against hot blast. This should be taken into account for the designs of the oxy-coal lance. [ABSTRACT FROM AUTHOR]

Pulverized coal injection (PCI) into blast furnace tuyere using two novel oxygen-coal lances has been designed by MCC Company. In this paper, a three-dimensional multi-phase model with Discrete Particle Model (DPM) approach has been developed to examine the performance of the novel oxygen-coal lance for PCI operation. Simulation conditions and properties of the PCI were obtained from the real operation conditions of the blast furnace of 580 m 3 with molten iron output of 1775 t/d in the industrial experimental base of MCC Incorporation. The simulation results of novel PCI style were also compared with the results of traditional one. Results show PCI using sing coal lance and single oxygen lance pattern is inferior to the conventional PCI mode. Its disadvantages include low BR increase, poor oxygen utilization level and potential damages to the tuyere. PCI using twin oxygen-coal lances is superior to the conventional PCI pattern. Its advantages include doubled burnout ratio, satisfying oxygen consumption level in the raceway and high temperature zone in a safe distance from the nozzle. [ABSTRACT FROM AUTHOR]

Abstract: Four dust samples were collected from a blast furnace (BF) for this investigation, two at all coke and two at Pulverized Coal Injection (PCI) operations. Samples of solid carbonaceous fuels (coals and coke) used in the evaluated BF were utilized. Char samples were produced in the laboratory from the pulverized coals used in PCI. The atomic structure of raw coke, chars and its parent coals used in PCI were investigated. This study utilized the X-ray diffraction technique (XRD) as a standard procedure to identify and differentiate the char and coke structures. This technique was used to quantify the proportions of fines of these carbonaceous materials in the BF flue dust samples. A simplified quantification was proposed. XRD of demineralized dust samples showed the unexpected presence of coke fines in quantities smaller than 63μm. The quantification of the carbonaceous material present in the BF off-gas samples is important information in order to evaluate the efficiency of the PCI process and the PCI coal combustibility, and it could be used to improve PCI performance in operating blast furnaces. [Copyright &y& Elsevier]

An updated approach to refining core indicators of pulverized coal used for blast furnace injection based on principal component analysis was proposed in view of the disadvantages of the existing performance indicator system of pulverized coal used in blast furnace. All the performance indicators of pulverized coal injection were taken into account in this presented method, including calorific value, igniting point, combustibility, reactivity, flowability, grindability, etc. Thereafter,the four core indicators of pulverized coal injection were selected and studied by using principal component analysis, namely, comprehensive combustibility P1, comprehensive reactivity P2 comprehensive flowability P3, and comprehensive grindability P4. The newly established core index system was not only beneficial to narrow down current evaluation indices but also effective to avoid previous overlapping problem among indicators by mutually independent index design. Based on overall 4 characteristic indexes, the injection characteristics evaluation index P was further introduced, and combined with fundamental characteristics evaluation index F, the final evaluation of pulverized coal performances was obtained. [ABSTRACT FROM AUTHOR]

The blast furnace process is the most important process to produce crude iron. The process energy is mainly covered by coke. However, the production of coke is connected with CO2 emissions and high costs. A significant measure to reduce the coke rate and with it the CO2 emissions plus costs is pulverized coal injection (PCI) through the tuyeres into the blast furnace. Further improvements can be achieved by using the Oxycoal+ technology. This article compares and shows the cost effectiveness and the decrease of CO2 emissions with the help of simplified energy balances for the only coke operation of the blast furnace, the operation using PCI and the operation using the Oxycoal+ technology. [ABSTRACT FROM AUTHOR]

Abstract: The simultaneous injection of pulverized coal (PC) and CO2-stripped blast furnace top gas (BFG) into the raceway of a blast furnace is an effective means of reducing carbon dioxide emissions in the ironmaking process. The BFG can be used as the cooling gas flowing through the annulus of coaxial lance. To stabilize the operation in the lower zone of blast furnace, the combustion characteristics of PC with/without BFG cooling gas within the blowpipe-tuyere-raceway region of a blast furnace are numerically investigated. The simulations focus on the effects of the lance configuration, the cooling gas type, and the cooling gas flow rate. The results show that a significant flow-induced pressure drop occurs at the blowpipe and tuyere part because of the gaseous combustion of the oxygen within the blast and the BFG injected via the lance. Moreover, the burnout of injected coal is significantly decreased with an increasing BFG cooling flow rates due to the additional oxygen consumption by the BFG. Finally, it is shown that a stronger swirling flow was formed when the lance configuration with bigger diameter was employed. Overall, the current numerical results provide a useful basis for improving the blast furnace performance in the future. [Copyright &y& Elsevier]

This paper presents results of researches conducted to determine the influence of pulverous solid additives at the combustion of coal dust blown into the furnace by means of derivatographic thermal analysis. Methods that gave the best results in solids research, especially in mineralogy but and other areas such as solid fuels research and their gasification processes are: differential thermal analysis, thermal gravimetry and derivative thermal gravimetry .These methods are applied separate or unitary with equipment developed by MOM - Budapest, Mettler, Switzerland etc. The temperature (T), mass change (TG), mass change rate (DTG) and enthalpy change (DTE) of a single test are simultaneously measured and it is realized, a complete characterization in terms thermograph investigated substance. [ABSTRACT FROM AUTHOR]

When analyzing the carrying out of a technological process or an aspect of a production process, in practice we obtain a lot of data as numerical values conditioned by a multitude of causes which may not be always submitted to a strict control. The statistical methods aim at obtaining certain tendencies and governing laws from the apparent chaos of numerical data and observations. Starting from these findings we will try to establish some methodologies for determining, with the help of the correlation and regression statistical analysis, the coke/coal dust replacement ratio. We will take into consideration the specific consumptions and other technological parameters of the pig iron elaboration process in the furnaces of ARCELOR MITTAL Galati. This way, besides the theoretical method based on the mathematical model analysis of the effect of coal dust blowing previously presented or other indirect calculation methods based on heat balance elements we will use a very effective analysis device, applied as a matter of fact on a large scale abroad, for determining, starting from experimental data, this parameter characteristic for the modern exploitation of the furnace. [ABSTRACT FROM AUTHOR]

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X-ray diffraction (XRD) is a standard technique of characterizing structure of materials. The aim of this work is to identify and quantify carbonaceous components (coal, char and coke fines) in the off-gas blast furnace (BF) through the use of the XRD technique and ultimate analysis. The dust collected in the off-gas BF, which contains char, coke fines, metallic oxides, etc., was fractioned and chemically analyzed. In addition, the fractions were grounded, demineralized and analyzed by ultimate analysis and XRD. This technique reveals differences in crystallite size of the carbonaceous materials. The coke structure shows to be more ordered (bigger Lc) than the char structure. Based on these differences, it is possible to quantify the fines proportions of char and coke in the blast furnace flue dust. The estimated char proportion in the carbonaceous material of the flue dust is 7%. [ABSTRACT FROM AUTHOR]

In order to understand the complicated phenomena of pulverized coal injection (PCI) process in blast furnace (BF), several mathematical models have been developed by the UNSW and BSR cooperation. These models are featuring from coal combustion in a pilot-scale test rig, to coal combustion in a real BF, and then to coal/coke combustion in a real BF, respectively. This paper reviews these PCI models in aspects of model developments and model applicability. The model development is firstly discussed in terms of model formulation, their new features and geometry/regions considered. The model applicability is then discussed in terms of main findings followed by the model evaluation on their advantages and limitations. It is indicated that the three PCI models are all able to describe PCI operation qualitatively. The model of coal/coke combustion in a real BF is more reliable for simulating in-furnace phenomena of PCI operation qualitatively and quantitatively. Such model gives a more reliable burnout prediction over the raceway surface, which could better represent the amount of unburnt char entering the coke bed. These models are useful for understanding the flow-thermo-chemical behaviours and then optimising the PCI operation in practice. [ABSTRACT FROM AUTHOR]

Abstract: A three-dimensional mathematical model of the combustion of pulverized coal and coke is developed. The model is applied to the region of lance-blowpipe-tuyere-raceway-coke bed to simulate in-furnace phenomena of pulverized coal injection in an ironmaking blast furnace. The model integrates not only pulverized coal combustion model in the blowpipe-tuyere-raceway-coke bed but also coke combustion model in the coke bed. The model is validated against the measurements under different conditions. The comprehensive in-furnace phenomena are investigated in the raceway and coke bed, in terms of flow, temperature, gas composition, and coal burning characteristics. The underlying mechanisms for the in-furnace phenomena are also analysed. The simulation results indicate that it is important to include recirculation region in the raceway and the coke bed reactions for better understanding in-furnace phenomena. The model provides a cost-effective tool for understanding and optimizing the in-furnace flow-thermo-chemical characteristics of the PCI operation in full-scale blast furnaces. [ABSTRACT FROM AUTHOR]

The article presents a study that examines the reactivity in carbon dioxide and the combustion behaviour of Brazilian coal (BC), imported coal (ICB), and charcoal (CC) in Brazil steel industry's pulverized coal injection (PCI) technology for blast furnaces (BF). It states that thermogravimetric analysis (TGA) was used to study the reactivity of the materials. Results showed that BC and CC blend have less ash content, high reactivity, and higher conversion degree compared to BC-ICB blend.

The article presents a study on improved char combustion model in blast furnace pulverized coal injection. The study dealt with the role of finite-rate heterogeneous reduction and oxidation. Moreover, particle temperatures were measured by an established Fourier Transform Infrared (FTIR) system. It concludes that the model gives better and faster particle temperature predictions and can be integrated easily into comprehensive computing codes for industrial pulverized coal flame.