Simulated Blast Furnace Research Articles

Co-incineration of multiple inorganic solid wastes towards clean disposal: Heat and mass transfer modeling, pollutant generation, and machine learning based proportioning

The co-disposal of solid waste by industrial kilns is presently attracting increasing attention. In this study, we investigate the co-disposal of solid waste, i.e. converter ash (CA), sintered ash (SA), blast furnace bag ash (BA), and municipal solid waste incineration fly ash (MSWIFA), under simulated blast furnace ironmaking conditions. The results show that it is feasible to use blast furnace to treat MSWIFA, but the stability of temperature field should be controlled in the process of co-disposal. With the increase of temperature, the conversion rate of NO decreased to 16.4%, and ZnFe2O4 became the main mineral composition, accounting for 75.53%. Corresponding to the flue gas corrosion condition of solid waste treatment, it is found that the corrosion resistance of the furnace material TH347H is better than 20G. Finally, based on the experimental data, the nested optimization algorithm of machine learning model is established to achieve the reverse output of optimal conditions. Overall, the study provides theoretical support and methodology guidance for the co-disposal of solid waste in blast furnaces in providing support for the further development of co-disposal of solid waste in industrial kilns.

Synthesis of AlPO-18 Zeolite Membrane by Sonication-Assisted Hydrothermal Method for H2 Separation from Blast Furnace Flue Gas

In this study, AlPO-18 zeolite has been synthesized at temperatures ranging from 140° to 180°C and varying synthesis time from 3 to 20 h using sonication mediated hydrothermal process. The characterization results of the synthesized powders and membranes revealed that phase pure AlPO-18 zeolite has been formed at 150°C for 15 h under sonication energy of 250 W. For comparison, the same has been synthesized by the conventional method for 200°C and 69 h. In the sonochemical process, H2O molecule splits into hydrogen radicals (H•) and hydroxyl (•OH) radicals with intense local heating and high pressure during the collapsing of cavitation, which initiates the formation of dihydrogen phosphite (H2PO3•) and dihydrogen phosphate (H2PO4•) radicals and facilitate the formation of AlPO-18 zeolite. Finally, the performance of the membranes has been studied with varying feed pressures for different binary gas mixtures and single gases, and simulated blast furnace (BF) gas has been used to study the separation efficiency of the membranes. The highest separation factors, calculated from BF mixture gas of H2/CO2 and H2/N2 have been achieved as 8.7 and 21, respectively. These results show the possibility of hydrogen recovery from BF flue gas to convert waste to wealth.

Desulfurization performance and mechanism for H2S from blast furnace gas over FAU zeolite sorbent

The desulfurization of blast furnace gas is crucial to meet the strict requirements for clean production of steel industry. However, the composition of blast furnace gas is complicated, and the gases of H2O, CO, CO2, and O2 would significantly affect the desulfurization activity. Therefore, the desulfurization performance for H2S in simulated blast furnace gas by Na-type FAU zeolites with different Si/Al was investigated. The physicochemical properties of zeolite sorbents were measured, and their correlation with desulfurization performance was studied. Moreover, the adsorption mechanism of H2S was investigated. The breakthrough sulfur capacity improved with the increase of relative crystallinity, Na+ content, specific surface area, and the decrease of Si/Al ratio. The adsorption mechanism of H2S on Na-type FAU zeolite was proposed. One is the hydrogen bond interaction between the bridging hydroxyl groups and H2S, and the other one is the base-acid interaction between sodium ion and H2S. In blast furnace gas, when interacting with Na+, H2S would be transformed into S, which further oxidized into thiosulfate and sulfate by O2.

Ammonia-induced CuO/13X for H2S removal from simulated blast furnace gas at low temperature

Blast furnace gas (BFG) is an important by-product energy for the iron and steel industry and has been widely used for heating or electricity generation. However, the undesirable contaminants in BFG (especially H2S) generate harmful environmental emissions. The desulfurization of BFG is urgent for integrated steel plants due to the stringent ultra-low emission standards. Compared with other desulfurization materials, zeolite-based adsorbents represent a viable option with low costs and long service life. In this study, an ammonia-induced CuO modified 13X adsorbent (NH3–CuO/13X) was prepared for H2S removal from simulated BFG at low temperature. The XRD, H2-TPR and TEM analysis proved that smaller CuO particles were formed and the dispersion of Cu on the surface of 13X zeolite was improved via the induction of ammonia. Evaluation on H2S adsorption performance of the adsorbent was carried out using simulated BFG, and the results showed that NH3–CuO/13X-3 has better breakthrough sulfur capacity, which was more than twice the sulfur capacity of CuO/13X. It is proposed that the enhanced desulfurization performance of NH3–CuO/13X is attributed to an abundant pore of 13X, and combined action of 13X and CuO. This work provided an effective way to improve the sulfur capacity of zeolite-based adsorbents via impregnation method by ammonia induction.

Enhancement of coal tar pitch carbonization with biochar: A metallurgical formed biocoke product produced by waste coke breeze and bamboo powder

The combustion of pulverized fuels in industrial production is inefficient and aggravates haze formation. A novel and green approach via synergetic using two solid waste resources (waste bamboo powder and waste coke breeze) for producing formed biocoke products as a metallurgical coke substitute was proposed in this study. A biochar with high fixed carbon (87.32 %) and low volatiles (2.49 %) was obtained by bamboo powder pyrolysis at 1000 °C for 30 min. Adding this biochar can enhance the strength of the formed coke product prepared using coke breeze with coal tar pitch as the binder. The cracks and pores between coke breeze particles inside the product can be filled by biochar, increasing the product's density. Furthermore, the carbonization of coal tar pitch as the binder can be improved by adding biochar, further enhancing the product strength. A formed biocoke product, with 34.5 MPa compressive strength, 41.29 % CSR and 30.59 % CRI, was obtained at a 2:8 mass ratio (biochar to coke breeze) by carbonization at 1100 °C under a nitrogen atmosphere for 30 min. The experiments of simulating blast furnace production using mixtures of the formed biocoke product with the metallurgical coke (with 21.12 % CRI and 64.58 % CSR) in different mass ratios were carried out. 4 % of the metallurgical coke for blast furnace ironmaking can be replaced by obtained formed biocoke product. This study achieved sustainable high-value-added recycling of coke solid waste resources. It can be an essential reference for recycling other pulverized solid fuels.

Non-isothermal kinetics of coke and iron ore melting reduction with variable activation energy model

Due to the significant consumption of coke in blast furnace ironmaking, a large amount of carbon emissions is generated. Thus, addressing the issues of energy conservation and carbon emission reduction in blast furnace ironmaking is imperative. The melting reduction reaction constitutes the predominant portion of carbon consumption during the ironmaking process. However, its kinetic behavior remains unclear to date, impeding energy-saving and carbon reduction efforts in blast furnaces. Consequently, this study conducted melting reduction experiments on two types of sinters and coke under simulated blast furnace conditions. A variable activation energy model (VAEM) was established for kinetic analysis of melting reduction. The conclusion is as follows: the variable activation energies of two types of sinters were determined to vary between 110 and 50 kJ/mol and 115–60 kJ/mol, the pre-exponential factors were 1.36 and 2.57. The deviation analysis showed that the predicted values using VAEM deviated from the experimental values by 1.17 % and 0.95 %. The reliability of VAEM was demonstrated. In turn, the kinetic behavior of coke and iron ore melting reduction was declared. It offers a theoretical basis for promoting the rational use of coke resources in blast furnace ironmaking and reducing carbon emissions.

Initial Study on Metal Dusting Behavior of Fe–Cr and Fe–Ni-Cr Alloys Under a Simulated Blast Furnace Operating Condition

Blast furnace ironmaking produces a reducing and carburizing atmosphere in the blast furnace which may lead to metal dusting. However, there is limited research on metal dusting under this particular atmosphere. This paper investigated metal dusting behaviors of ferritic Fe-(10, 20, 25)Cr and austenitic Fe-20Cr-(20, 33)Ni, Fe-25Cr-20Ni (wt.%) alloys at 550 and 650 °C in an Ar-33CO-7H2-7CO2-2H2O (vol.%) gas simulating a blast furnace operating condition. A relatively short reaction time, up to 100 h, was used to evaluate the initial stage of metal dusting of these alloys in the blast furnace gas condition. Severe metal dusting and coke deposition were observed at 550 °C, while no significant dusting but internal oxidation and carburization were observed at 650 °C. Higher Cr and Ni contents in the alloy lowered kinetics of metal dusting at 550 °C and of carburization at both temperatures. Austenitic alloys were more susceptible to metal dusting and coke deposition than ferritic alloys with the same Cr content at 550 °C. At 650 °C, however, ferritic alloys experienced higher extents of carburization and oxidation than austenitic alloys with the same Cr concentration. The effects of alloy composition and reaction temperature on metal dusting in this simulated blast furnace operating condition were discussed.

A novel ironmaking decarbonisation technology — co-injection of hydrogen and biochar (CoHB): A CFD study of combustion in the raceway under simulated blast furnace conditions

In this paper, a novel ironmaking decarbonisation technology — co-injection of hydrogen and biochar (CoHB) in blast furnaces (BFs) is proposed for a feasible and sustainable carbon-neutral ironmaking. As the first study, to understand the fundamentals of internal combustion behaviour in the raceway related to CoHB, a three-dimensional (3D) computational fluid dynamics (CFD) model is developed to describe the multiphase reacting flow under simulated BF conditions. Particularly, the present model features a new treatment of volatile matter (VM) and an improved sub-model for hydrogen combustion. The model is successfully validated by the measurements of biochar injection and co-injection of hydrogen and coal, respectively. The typical in-furnace phenomena as well as the interaction between the hydrogen and biochar are analysed comprehensively. The results indicate that the proper injection of hydrogen through the annulus of the fuel lance is beneficial as the high local gas temperatures (1500 K to 1800 K) from the hydrogen combustion provide a biochar burnout enhancement of 6% during the biochar devolatilisation process. However, char reactions are hindered due to the oxygen competition with hydrogen combustion, resulting in a slightly reduced final biochar burnout. This study provides a quantitative insight into the combustion details related to this novel technology and serves as a reference to strive towards the net-carbon ironmaking initiative.

Microalgae blending for sustainable metallurgical coke production – Impacts on coking behaviour and coke quality

The steel industry is responsible for approximately 7% of global greenhouse gas emissions, mainly in the form of CO2 from the blast furnace ironmaking process. Among several strategies proposed to reduce CO2 emission, the partial replacement of coal with biomass during the cokemaking process has gained increasing interest. However, such replacement with lignocellulosic biomass species demonstrates a detrimental effect on coke quality. In this work, as an alternative to lignocellulosic biomass, the use of microalgae biomass (Chlorella vulgaris) is discussed for coal blending and bio-coke production. Three Australian metallurgical coal samples, varying in rank and fluidity, were blended with microalgae at up to 10 wt% to evaluate the impact of biomass addition rate on coking behaviour and coke quality. The work evaluates the impact of microalgae on coal blend properties, coking performance, and coke quality and strength (CSR/CRI, microtexture, and coke reactivity). The results demonstrated that microalgae blending with high-rank premium metallurgical coals did not adversely affect thermoplastic properties during coking or resultant bio-coke quality. Furthermore, the reactivity under simulated blast furnace conditions showed that microalgae addition led to a slight increase of up to 4.4% in coke gasification reactivity, which was attributed to the higher alkali content and isotropic textures in coke. Unlike lignocellulosic biomass, in bio-cokes produced by blending microalgae no porous and fibrous structures related to the biochar structure were identified. It was postulated that this non-fibrous nature of microalgae allows cokes to maintain their strength even for blending up to 10 wt%.

Development of softening and melting testing conditions simulating blast furnace operation with hydrogen injection

ABSTRACT Softening and Melting (S&M) experiments have evolved alongside the blast furnace as a crucial tool for burden characterisation and optimisation. Modern blast furnaces derive a base load of hydrogen from various sources. However, with hydrogen-enrichment of the blast furnace being considered to mitigate emissions, new S&M test conditions are required. In this study, a 2-D axisymmetric CFD model is used to simulate the internal conditions of a modern blast furnace operation, and a future operation with tuyere level hydrogen injection. The model results are used to guide the development of novel S&M test conditions, inclusive of H2, H2O, CO, CO2 and N2. The maximum hydrogen concentration under hydrogen enrichment was 20%, with the hydrogenous fraction of the gas primarily replacing nitrogen. A particular focus was given to the importance of including water vapour in the inlet gas, andits impact on reactions occurring in the S&M test.

Evolution behavior and mechanism of iron carbon agglomerates under simulated blast furnace smelting conditions

Evolution behavior and mechanism of iron carbon agglomerates under simulated blast furnace smelting conditions

Removal of H2S from simulated blast furnace gas by adsorption over metal-modified 13X zeolite

With the promulgation of new regulations, it’s of great significance to desulfurization from blast furnace gas (BFG) to meet the clean production of iron making industry. Among different desulfurization technologies, zeolite-based sorbents are extensively studied due to the easy operation, low operating cost, and long service life. In this research, the 13X zeolite was selected, and it was ion-exchanged by different metal elements (Cu, Zn, Co, Mn) to prepared a series of sorbents. A fixed bed was used to evaluate their desulfurization behavior, and the XRD, SEM, ICP-OES, XPS, N2 adsorption, and CO2-TPD were carried out to characterize the physical and chemical properties of sorbents. The effects of water vapor content and desulfurization temperature on the removal of H2S were investigated. The regeneration performance of sorbent was also explored. The results showed that the Cu25X-Ex sorbent has the highest breakthrough sulfur capacity of 7.71 g S/100 g sorbent in dry simulated BFG. The breakthrough sulfur capacity of Cu25X-Ex was 4.52 g S/100 g sorbent when the water vapor content is 5 %. The CO2-TPD results showed that the basic sites were favorable for the adsorption of H2S on the surface of zeolite. The XPS results illustrate that the forms of S adsorbed on Cu25X-Ex sorbent were CuS, CuS2O3, and CuSO4, so it is suggested that the reaction between adsorbed H2S with the metal cations in sorbent occurred subsequently. The research indicated that Cu25X-Ex sorbent has potential applicability in the desulfurization of blast furnace gas.

Softening and melting performance of mixed burden under the simulated hydrogen-rich blast furnace atmosphere

ABSTRACT The effects of the application of iron coke in hydrogen-rich blast furnace atmosphere on the softening and melting performance of burden were studied.The results indicated that with the increase in hydrogen content, the cohesive zone of mixed burden became narrower and the permeability of charge was improved, and the suitable hydrogen content was 10vol.-%. The application of iron coke could promote the iron ore reduction and carburizing of iron, decrease the melting temperature by 1–10°C, decrease the dripping temperature by 5–16°C, narrow the cohesive zone, improve the air permeability with S value decrease of 3.19–13.87 kPa °C, and reduce the dissolution loss of coke and ensure the skeleton function of coke. The suitable burden structure was confirmed as follows, i.e. the ratio of pellets and sinter is 4:6, and the ratio of iron coke and coke is 2:8.

Gasification of iron coke and cogasification behavior of iron coke and coke under simulated hydrogen-rich blast furnace condition

Gasification of iron coke and cogasification behavior of iron coke and coke under simulated hydrogen-rich blast furnace condition

Reduction of Acid Iron Ore Pellets under Simulated Wall and Center Conditions in a Blast Furnace Shaft

The operational conditions, including temperature and gas composition, vary along the radial position in a blast furnace. Nevertheless, very few studies can be found in the literature that discuss how the reduction behavior of the ferrous burden varies along the radial position. In this study, the effect of the radial charging position on the reducibility of acid iron ore pellets was investigated using a laboratory-scale, high-temperature furnace in CO-CO2-N2 and CO-CO2-H2-H2O-N2 atmospheres up to 1100 °C. The experimental conditions were accumulated based on earlier measurements from a multi-point vertical probing campaign that was performed for a center-working European blast furnace. The main finding of this study is that the pellet reduction proceeded faster under simulated blast furnace conditions resembling those in the center area, compared to the wall area, because of a higher share of CO and H2 in the gas. Therefore, the pellet charging position affects its reduction path in a blast furnace. Additionally, it was shown that the presence of H2 and H2O in the reducing gas enhanced the progress of reduction reactions significantly and enhanced the formation of cracks slightly, both of which are desirable in blast furnace operation. The reducibility data attained in this study are important in understanding how temperature and gas composition is connected to the reduction degree under realistic process conditions.

CO recovery from blast furnace gas by vacuum pressure swing adsorption process: Experimental and simulation approach

This paper presents experimental and numerical approaches to use a four-bed, six-step CO vacuum-pressure-swing adsorption (VPSA) process with CuCl/boehmite adsorbent to extract carbon monoxide (CO) gas from a simulated blast furnace gas (BFG; N2:CO:CO2 = 60:20:20 mol %) at setting temperature Tset = 60 °C and adsorption pressure 2.5 bar ≤ Pad ≤ 6.4 bar. The cyclic adsorption isotherms of pure CO2 and CO on CuCl/boehmite pellets were measured at temperature range, 20 °C ≤ Tset ≤ 60 °C using a volumetric method. At Tset = 60 °C, the CO-adsorption capacity was stable during cyclic operation, with negligible hysteresis between adsorption and desorption processes. A mathematical model of four-bed, six-step CO-VPSA was developed; this model successfully reproduced the bench-scale experimental data. A sensitivity analysis of the effect of feed flowrate, rinse flowrate, and desorption pressure on CO purity and recovery was conducted to improve the efficiency of the CO enrichment. Simulations show that 79.9–87.4 mol % of CO recovery could be attained with >90 mol % purity of CO, and 71.8–81.8% CO recovery could be achieved with >99 mol % purity of CO at Tset = 60 °C and 2.5 bar ≤ Pad ≤ 6.4 bar. This method to recover CO from emissions by the steel-making industry can detoxify them, and the CO can be used in syntheses of value-added chemical products.

A Simple Method of Evaluating the Thermal Properties of Metallurgical Cokes under High Temperature.

The reactivity index of weight loss (RI) and tumbling strength after the reaction (I10600) of manufacturing coke were first tested at a temperature series of 1100, 1200, and 1300 °C under CO2 atmosphere with different compositions and duration times to study the effects of temperature, time, and gas composition on coke hot strength. Then the RI/I10600, carbon structure, and optical texture of the cokes prepared from different single coals were mainly studied after a solution reaction with CO2 under a high temperature of 1300 °C and a standard temperature of 1100 °C. It was found that temperature greatly affects the RI/I10600 of coke, especially at high temperatures up to 1300 °C. Compared with standard tests under 1100 °C, the changes of RI/I10600 for different cokes are very different at 1300 °C, and the changes are greatly related to coke optical texture. Under a high temperature in the testing method, the tumbling strength of cokes with more isotropy increased, whereas it decreased for those with less isotropy. This simple method of using high temperature could yield the same results when compared with complicated simulated blast furnace conditions.

Non-isothermal reduction process analysis of iron-bearing burden with charging iron coke hot briquette under simulated blast furnace conditions

Non-isothermal reduction process analysis of iron-bearing burden with charging iron coke hot briquette under simulated blast furnace conditions

Model for the approximate assessment of nitrogen content in swollen reduced iron ore from single measurements

A method of calculation has been derived to assess the nitrogen estimated content in iron reduced samples. The method is based on the review of observations and laboratory measurements of relationships between the rate of reduction and the corresponding metallic iron formation during the reduction process. The metallic iron formation has been calculated from relationships that apply to a wide variety of types of ores undergoing reduction under a nitrogen-containing gas mixture in proportions above 50% by volume. The empirical correlations found between the rates of metallization, the sample swelling index, and the equilibrium nitrogen solubility in iron can be used for determined the approximate final content of nitrogen in the reduced samples from the estimated and measured final volume of the reduced specimens. It is necessary to have an accurate analysis of the starting sample as well as the reducibility information.
 Keywords: Iron ore, nitriding, catastrophic swelling, rate of metallization, reduction degree.
 [1]M. Kumar, B. Himanshu & S. Kumar. “Reduction and Swelling of Fired Hematite Iron Ore Pellets by Non−coking Coal Fines for Application in Sponge Ironmaking”. Mineral Processing and Extractive Metallurgy Review- MINER PROCESS EXTR METALL REV. 34. 10.1080/08827508.2012.656776. 2012.
 [2]I. Mikko, M. Olli, A. Tuomas, V. Ville-Valtteri, K. Jari, P. Timo & F. Timo. “Dynamic and Isothermal Reduction Swelling Behaviour of Olivine and Acid Iron Ore Pellets under Simulated Blast Furnace Shaft Conditions”. ISIJ International. 52. 1257-1265. 10.2355/isijinternational.52.1257. 2012.
 [3]M. Kumar. “Study of reduction kinectics of iron ore pellets by noncoking coal”. Thesis of Master. National Institute of technology, Rourkela. 2009.
 [4]O. Dam. “The Influence of Nitrogen on the Swelling Mechanism of Iron Oxides During Reduction”. PhD Thesis .Univ. of London. 1983.
 [5]O. Dam and J. Jeffes. “Model for the Assessment of Chemical Composition of reduced iron ores from single measurements”. Ironmaking and Steelmaking Journal. Vol. 14, N`5. 1987.
 [6]O. Dam. “Efecto de la descomposición de gas de amoniaco (NH3) sobre el hinchamiento de óxidos de hierro durante reducción”. UCT Journal. Vol 100, 24. May 2020.
 [7]R. Agarwal and S. Hembram. “To Study the Reduction and Swelling Behavior Iron Ore Pellets”. BSc. Department of Metallurgical and Materials Engineering National Institute Of Technology, Rourkela. May 2013
 [8]Z. Chen , C. Zeilstra , J. Van der Stel , J. Sietsma & Y. Yang. “Review and data evaluation for high-temperature reduction of iron oxide particles in suspension”. Ironmaking & Steelmaking. Vol. 47. N°7. pp. 741-747. 2019.

Modelling of CO <sub>2</sub> and H <sub>2</sub>O Interaction During Adsorption Cycles on Hydrotalcite for SEWGS Applications

Sorption Enhanced Water Gas Shift (SEWGS) is an intensified pre-combustion capture process, based on a potassium promoted Mg/Al-hydrotalcite sorbent. The technology has demonstrated low energy requirements and high capture performances in real industrial settings within the Iron and Steel sector. Reactor modelling is an essential tool to develop energy and cost-efficient SEWGS units. The TNO developed model captures the fundamentals of the gas-solid thermodynamic and kinetic interactions, to accurately predict the multi-column behaviour, allowing for unit sizing and quantification of the energy requirements. The updated interaction model consists of Langmuir interaction for CO2, a competitive interaction site for CO2 and H2O, an exchange site where either CO2 or H2O is adsorbed and a pore condensation for high-pressure H2O. The updated model is validated against single column and multi-column operation with simulated blast furnace gas.