Furnace Gas Research Articles

Thermal Stress Analysis of Blast Furnace Hearth with Typical Erosion Based on Thermal Fluid-Solid Coupling

The life of the hearth is the main limiting link of the campaign of a blast furnace. As the equipment for holding molten iron in the furnace, the high-temperature molten iron is in direct contact with the refractory, which makes the refractory have a larger temperature increase. If the temperature gradient inside the refractory is large, it generates large thermal stress and causes the refractory to crack. Blast furnace gas and molten iron intrude into the gap, which directly causes melting erosion and other chemical erosion with carbon bricks. It aggravates the erosion degree of the furnace and seriously affects the production life of the furnace. Therefore, the furnace often occurs with different types of severe depression erosion in the late service of the blast furnace. In this study, the calculation model of the thermal fluid-solid coupling considering the molten iron flow and the solidification of molten iron was established. This calculation model was applied to study thermal stresses in the furnace with severe erosion. Based on the calculation model, the effect of blast furnace production parameters and deadman condition on thermal stresses in the furnace with severe depression erosion were analyzed, including tapping productivity, tapping temperature, cooling intensity, and deadman geometry. The research results are of great significance for prolonging the safe production life of blast furnaces.

Breakthrough analysis for parameter estimation of CO2 adsorption on pelletized flexible metal–organic framework

Pellets of elastic layer-structured metal–organic framework-11 (ELM-11), one of the flexible metal–organic frameworks (MOFs), were prepared by mixing ELM-11 powder with a cellulose binder, and the CO2 adsorption behavior of ELM-11 pellets in a fixed-bed adsorber was analyzed to estimate equilibrium and kinetic parameters. Adsorption breakthrough tests were performed under various conditions for the simulated flue gas (20 % CO2–80 % N2) of a blast furnace gas in addition to CO2 isotherm measurements. Experimental CO2 adsorption isotherms on ELM-11 followed a weighted dual-site Langmuir equilibrium model well. The breakthrough analysis results by numerical calculation using the equilibrium model suggested that the gate-opening pressure of ELM-11 shifted to a lower pressure through repeated breakthrough tests. The CO2 adsorption kinetics on ELM-11 pellets agreed well with the linear-driving-force model. Furthermore, CO2 adsorption behavior under various conditions was described well by a mathematical model using a constant value of the mass transfer coefficient under the condition of this study, which was validated against additional experimental data. In addition, it was found that the mass transfer becomes slow under certain conditions that the driving force of the phase transition of ELM-11 is smaller than a threshold, where the amount of CO2 adsorbed on the breakthrough tests did not reach the equilibrium capacity of CO2, which may because the rate-limiting step may be dependent on the CO2 partial pressure and temperature.

Experimental study on the fire performance of prestressed steel parallel wire strands

Bridges are critical components of the transportation system and any damage to these structures can result in important social and economic consequences. The literature concerning design standardization for fire hazard in suspension bridges is limited. High strength prestressed steel cables serve as main load-bearing components for suspension bridges, and exposure to high temperatures may result in their prestress loss, leading to structural failure. This paper experimentally investigates the fire performance of 19-parallel wire strands (PWS cables) with a tensile strength of 1860 MPa used as suspender cables in long-span suspension bridges. PWS cables were prestressed and then subjected to UL1709 hydrocarbon fire and simulated open pool tanker fire scenarios in the gas furnace until failure. The load–deflection plots of PWS cables suggest that the cables at ambient temperature sufficiently withstood 95% of their ultimate load capacity. However, the unprotected PWS cables failed within 3–8 min in the fire tests but still sustained the load at 400 °C, which confirms the conservative estimation of 300 °C critical cable temperature mandated by the Post-tensioning Institute. The stress–strain data of tested steel wires correlated well with recently developed high-strength steel wire material models at elevated temperatures. The wire rupture surfaces indicated a brittle failure at ambient temperature and a ductile failure with visible necking under fire conditions. The ultimate (rupture) strain capacity of steel wires decreased from 5% to almost 1% during fire tests. Further, the post-fire strength of PWS cable was unchanged but the elasticity modulus increased by 19% and the rupture strain decreased by 20%. The experimental findings indicate the necessity of fire protection application on PWS cables to keep cable temperatures below the critical temperature of 400 °C in a fire hazard.

Blast furnace gas decarbonisation through Calcium Assisted Steel‐mill Off‐gas Hydrogen production. Experimental and modelling approach

The Calcium Assisted Steel-mill Off-gas Hydrogen production process (CASOH) is able to upgrade and decarbonise blast furnace gases (BFG), which is the main source of CO2 emissions in integrated steel making plants. The three main reaction stages of the process (i.e. H2 production via calcium-assisted water-gas-shift of BFG, Cu oxidation and CO2 sorbent regeneration) have been investigated in a lab-scale fixed bed reactor, using readily available functional materials (i.e. a commercial Cu-based catalyst and calcined limestone for the CO2 capture). The reactivity and stability of the materials have been studied after multiple cycles resembling the operating conditions expected in a TRL7 CASOH pilot plant under construction. A one-dimensional reactor model has been developed to simulate in detail the CASOH process and successfully validated with the experimental results obtained in the packed-bed reactor. Synthetic BFG mixed with steam has been converted into a product gas containing up to 40 vol% of H2 in N2 during the CASOH stage at atmospheric pressure and average temperatures in the bed around 650 ºC. During the Cu oxidation stage, the O2 contained in inlet air has been completely converted leading to moderate temperatures in the oxidation front (i.e. around 800 ºC). The oxidation at 4 bar has minimized the CO2 leakage during this stage. Finally, the reduction of CuO with simulated BFG and CH4 has produced in-situ sufficient heat to partially calcine at temperatures around 880ºC the CaCO3 present in the reactor leaving the solids ready for subsequent reaction cycles, while a CO2-rich gas is produced. The experimental and modelling results obtained in this work will be used to firstly design the experimental campaigns at the TRL7 CASOH pilot, and subsequently to interpret and scale up the pilot results using the validated model.

Optimizing choice of polypropylene fiber geometry for preventing spalling of high performance concrete due to fire

This article presents a work on optimization of choice of polypropylene fiber dosage and geometry to ensure thermal stability of high performance concrete subjected to fire. Three cementitious materials with different granular skeletons containing polypropylene fibers are studied. Experimental campaign of fire tests is conducted on uniaxially compressed concrete prisms via mobile gas furnace. Then, thermo-mechanical simulations are accomplished to validate experimental findings. Results show that an optimal PP fiber length should be selected in accordance with aggregate size. PP fiber diameter has shown to have no significant influence on spalling prevention.

Catalytic Oxidation of Phosphine by Aqueous Copper–Ammonia Complexes

The furnace gas resulting from the electrothermal production of yellow phosphorus contains up to 95% CO, 2% O2, 2% H2, and 0.3–4.0% impurities, including phosphine (PH3), yellow phosphorus (P4), and hydrogen sulphide (H2S), which are characterized by flammability, explosion hazardousness, corrosiveness, and high toxicity. The presence of toxic impurities does not allow the use of waste gases from phosphorus production, which are mainly composed of valuable carbon monoxide, as chemical raw materials and/or process fuel. The authors propose a method for the purification of furnace gas from the main toxic component, phosphine, by its oxidisation using aqueous copper–ammonia complexes as a catalyst. This approach allows the cleaning process to be conducted under mild conditions. The degree of purification of the model furnace gas from P components is 90–99%, depending on the process conditions.

From Fossil‐Fueled to Hydrogen‐Fueled Annealing Furnaces: Effects on the Oxidation of Stainless Steels

The possibility of replacing methane with hydrogen as the fuel gas in an annealing furnace is studied regarding the oxidation of ferritic AISI 441 and austenitic AISI 304 stainless steels during simulated short‐term annealing. Oxide‐scale formation using the simulated atmospheres based on methane–air, methane–oxygen, and hydrogen–oxygen combustions with different oxidant gas excesses is compared at steel grades’ furnace temperature ranges in an annealing process. Thermogravimetry is used to determine variations of weight gain during oxidation, and field‐emission scanning electron microscopy and glow discharge optical emission spectroscopy are used to characterize oxide scales. The transition to H2 as the fuel gas is more suitable for the ferritic grade than the austenitic grade at the studied temperatures. High water vapor content in hydrogen– and methane–oxygen combustion atmospheres promotes breakaway oxidation for both steel grades. Nodule formation is significantly observed under the most demanding annealing conditions for the ferritic grade, while only the lightest conditions remain without the signs of breakaway oxidation for the austenitic grade. Changes in the oxide‐scale structures produced in both hydrogen–oxygen and methane–oxygen atmospheres are in significant, which can facilitate the exchanges between these atmospheres in relation to methane–air combustion.

CFD Modeling and Validation of Blast Furnace Gas/Natural Gas Mixture Combustion in an Experimental Industrial Furnace

The use of residual gases from steel production processes as fuel for steel treatment furnaces has attracted great interest as a method for reducing fossil fuel consumption and the steel footprint. However, these gases often have a low calorific value, and a direct substitution can lead to low temperatures or combustion instability issues. CFD simulations of the combustion of these gases can help steel producers forecast the results of the substitution before real testing and implementation. In this study, a CFD model of an industrial experimental furnace in the steel sector is developed and validated. The results are calculated using the combustion, radiation, and heat transfer models included in the software Ansys Fluent. The validation of the simulated results is performed with data acquired from experimental tests under the same simulated conditions at three air-to-fuel equivalence ratios, which vary from an excess of 0% to an excess of 5% oxygen at the outlet. The model is adjusted to the results, capturing the trends of the measured physical variables and pollutant concentrations. In the case of the combustion temperature, the differences between the simulated and measured values vary from 0.03% to 6.9. Based on the simulation results, the use of blast furnace gas as fuel produces temperatures inside the chamber between 1004 °C and 1075 °C and high stream velocities because of the high flow needed to keep the power constant. Flames exhibit straight movements since the high flows absorb the effect of the swirling flames. The addition of natural gases increases the combustion temperature up to 1211 °C and reduces the flow and length of the flames. Finally, temperatures up to 1298 °C and shorter flames are reached with natural gas enriched with a stream of oxygen, but in this case, NOx emissions need to be controlled.

Hybrid prediction method of blast furnace gas generation considering multi-operation modes in steel plants near the city

Blast furnace gas (BFG) generated in blast furnace (BF) ironmaking process can be converted into steam and electricity to provide energy for the nearby cities. Accurate prediction of BFG generation is crucial for assessing BFG surplus, which is the difficult problem faced by steel plants. A hybrid prediction method is proposed to solve it, which is named Radial Basis Function Neural Network (RBFNN) Based on Improved Genetic Algorithm (IGA) and Grey Relation Analysis (GRA). BF’s operation modes, including smooth, blown-down, blow-down to 0, blow-in, were classified to exclude the unrelated feature factors and set the adaptive prediction horizon. Then feature factors related to BFG generation are quantitatively analyzed by GRA in different operation mode, which affects the structure of RBFNN. And the key parameters of RBFNN is optimized by IGA. Proposed method is validated by a case study from a China’s steel plant. The results show the hybrid method has the obvious advantage with the MAPE of 3.31 %, 3.22 % and RMSE of 337.57 m3 in blow down, blown-in and smooth operation mode, respectively. This paper helps steel plants assess how much steam and electricity converted from BFG can be sent to its nearby cities, and contributes to energy resources utilization.

NARX Deep Convolutional Fuzzy System for Modelling Nonlinear Dynamic Processes

This paper presents a new approach for modelling nonlinear dynamic processes (NDP). It is based on a nonlinear autoregressive with exogenous (NARX) inputs model structure and a deep convolutional fuzzy system (DCFS). The DCFS is a hierarchical fuzzy structure, which can overcome the deficiency of general fuzzy systems when facing high dimensional data. For relieving the curse of dimensionality, as well as improving approximation performance of fuzzy models, we propose combining the NARX with the DCFS to provide a good approximation of the complex nonlinear dynamic behavior and a fast-training algorithm with ensured convergence. There are three NARX DCFS structures proposed, and the appropriate training algorithm is adapted. Evaluations were performed on a popular benchmark—Box and Jenkin’s gas furnace data set and the four nonlinear dynamic test systems. The experiments show that the proposed NARX DCFS method can be successfully used to identify nonlinear dynamic systems based on external dynamics structures and nonlinear static approximators.

Behavior of cross-laminated timber panels during and after an ISO-fire: An experimental analysis

Cross-laminated timber has been used in buildings since the 1990s. In the last years, there has been a growing interest in the use of this technology, especially with the adoption of the product in increasingly taller buildings. Considering that the product is manufactured from a combustible material, wood, authorities that regulate the fire safety in buildings and the scientific community have carried out numerous research and fire tests, aiming to elaborate codes which contemplate the use of cross-laminated timber in tall buildings. This paper discusses the main results obtained from the fire resistance test of a cross-laminated timber slab carried out in the horizontal gas furnace (3.0 m × 4.0 m x 1.5 m) from the University of Sao Paulo. A vertical load of 3 kN/m2 was applied over the slab and the specimens were exposed to the standard fire curve for 30 min. In addition to the 30-min test, the research also evaluated the thermal behavior of the samples during the 24 h after the burners were turned off. Throughout the test, the slab maintained the integrity and the thermal insulation, and no falling-off of the charred layer was observed. However, the 24-h test indicated that it is mandatory to consider the loss of stiffness and strength of timber caused by the thermal wave observed during the decay phase.

Increasing the efficiency of the use of oil fuel in thermal power stations and boilers

An organization can achieve good results by properly managing the supply of fuel, ensuring the desired intensity of combustion, and optimizing the volume of the combustion process to promote complete combustion. Additionally, the mixing of fuel with secondary air, provided by combustion devices, is crucial for achieving efficient combustion. Experimental studies conducted on boilers in thermal power plants have demonstrated that heating the secondary air can enhance energy efficiency. This improvement is particularly relevant for fuel oil and gas burning. To optimize the combustion of fuel oil, steam-mechanical nozzles are commonly utilized. These nozzles excel in prolonging the combustion process, leading to more efficient fuel oil burning. When burning gas and fuel oil, a two-stage arrangement of burners in the boiler is more effective than a single-stage configuration, regardless of whether the burners are positioned in opposite directions or in a one-sided frontal arrangement. To mitigate the emission of nitrogen oxides, several measures can be taken. It has been observed that recirculating flue gases from the heat is more effective than solely utilizing flue gas. Additionally, the strategic placement of boilers with furnace gases and the optimization of turning parameters can also contribute to reducing harmful nitrogen oxide emissions.

SYSTEM DYNAMICS MODELLING AND SIMULATION OF COMPUTER CONTROL SYSTEMS FOR STEEL INGOT FURNACES

The problem that necessitated this study was that some furnaces that were responsible for the further processing of steel pipes at Company X were not connected to a programmable logic control (PLC)–Internet of Things (IoT) system. This slowed down the product flow. To address this problem, PLC-IoT systems were integrated so that the production system could be more effective. This study therefore models and simulates the integrated PLC-IoT control system, using the system dynamics modelling approach to investigate the performance of the automated gas furnaces. The PLC-IoT consists of an internal module that is used to process the data stream. After the implementation of the proposed control system, primary data was acquired by continuously evaluating the performance of the system. The research methodology used involved quantitative analysis and a simulation model using the Anylogic software. The result of the delivery and inventory of ingots from an automated system showed an upward trend with delivery and an inventory of an ingot at about 90 minutes; while a system that was not automated with PLC-IoT showed a downward trend of ingots. This shows that the introduction of the PLC-IoT for control makes the system more effective. The findings of this work could assist the manufacturers in achieving manufacturing or production efficiency, significant time savings, and better monitoring of the manufacturing process. Keywords: Automation, Control system, Gas furnace, PLC-IoT, Simulation

Аналіз розвитку технологій задувки доменних печей в 20-21 століттях

The article discusses the trends and classification of blast furnace blowers over the past 100 years. The development of blower technology is divided into 3 periods: The 1st period lasted until the end of the 30s of the XX century, characterized by a lack of scientific knowledge, mysticism and based on previous experience; the 2nd period - until the early 70s, when the "traditional" blower technology was mastered with one problem - difficulties with opening the first releases and simultaneous overheating of the top; the 3rd period continues today, it includes the development of new methods for intensifying heat transfer during blowing and scientific generalization of blower techniques. The main tasks of blowdown are to bring the blast furnace back to normal operation in a short time, in compliance with safety rules, without significant costs, and to preserve the blast furnace and auxiliary equipment for long-term productive operation. These tasks are closely linked to the design features of blast furnaces, including the cooling system, lining type and furnace size, which have steadily increased from less than 500 m3 to 5,600 m3. The complexity of understanding the processes of heating the charge column during the blowing period with the formation of a gas flow and a cohesion zone in it is the reason for numerous discussions about rational blowing methods: methods for calculating and placing layers of the blast furnace charge, the use of various hot blast additives (nitrogen, natural, blast furnace or coke oven gas, oxygen, steam, etc.), the rate of increase in hot blast flow and its temperature, the trend of pressure drop along the height of the charge column. The use of wood in the blast charge, the installation of constrictor rings in air tuyeres or the closure of a part of the tuyeres for blowing are discussed. Recommendations for blast furnace blowers are given. A comparison of "traditional" blowing with "progressive" blowing and blowing with nitrogen developed at the Iron and Steel Institute National Academy of Sciences of Ukraine are presented.

Утилізація надлишкового газу УСГК

COKE DRY COOLING PLANT EXCESS GAS UTILIZATION © S.A. Kravchenko, PhD in Technical Sciences (STATE ENTERPRISE "STATE INSTITUTE FOR DESIGNING ENTERPRISES OF COKE OVEN AND BY-PRODUCT PLANTS'' (SE "GIPROKOKS'')", 60 Sumska str., Kharkiv, 61002, Ukraine), D.V. Miroshnichenko, Doctor of Technical Sciences (National Technical University "Kharkiv Polytechnic Institute", 61002, Kharkov, Kirpichev str., 2, Ukraine) At coke-chemical enterprises, that operate coke dry cooling plants, due to the peculiarities of the technology, an excess of circulating gas is formed, which must be constantly removed from the closed circuit. This article examines two operating plants designed for the utilization of excess circulating gas, and also presents some experience of their exploitations. In particular, information is provided on the method of disposal of excess circulating gas of coke dry cooling plants in an additional boiler by burning it in a mixture with coke gas. The main equipment of the recycling unit is a KO-10 steam boiler with forced circulation and a U-shaped arrangement of heating surfaces, located in the building of the boiler coke dry cooling plant of coke batteries of one of the coke-chemical enterprises. Tests and operation of the plant confirm the possibility of producing a couple of energy parameters on it with the achievement of high environmental indicators as a result of the utilization of excess gas of the coke dry cooling plant. The second direction considered is the use of excess gas from the coke dry cooling plant as fuel. The possibility is shown of increasing its calorific value as a result of mixing circulating gas with gas of higher calorific value – in particular with blast furnace gas. It is shown that the existing positive experience of operating the mentioned installations allows recommending both directions for the utilization of excess circulating gas for use on existing and newly designed coke dry cooling plants. According to the article, the work experience, a lot of experiments and performed calculations indicate the expediency of maintaining the regime with the maximum permissible content of CO in the circulating gases during the operation of the coke dry cooling plants. This allows to increase the quality indicators of coke. The high content of CO in the circulating gases also makes it possible to significantly reduce losses from coke burning in the process of dry cooling. Keywords: coke dry cooling, recovery boiler, circulating gas, excess, utilization, additional boiler, increase in calorific value, CO content, coke quality. Corresponding author S.O. Kravchenko, e-mail: sa_kravchenko@giprokoks.com

ФОРМУВАННЯ МІЖНАРОДНОЇ СТРАТЕГІЇ РОЗВИТКУ РИНКУ СТАЛІ

The article examines the structure of strategic consumers of the metallurgical industry. The most important industries in the structure of consumption of the metallurgical sector are: industrial and civil construction, machine building (mechanical equipment and automobile industry). The integrated types of steel production are identified: based on blast furnace (BF) and basic oxygen furnace (BOF) and electric arc furnace (EAF) steel production technology type. The structural components of the operating cycle of the main types of steel production (iron ore, coal, limestone, scrap, energy), as well as the components of commercial products (main industrial products and related products): steel, sludge, dust, blast furnace gas, converter gas, recovered steam are defined, energy. The cost norms of the material and energy supply sector of the metallurgical sector and the results of metallurgical production in average quantitative terms are substantiated. The trend of global steel production was analyzed and analytical indicators of dynamics were determined (average absolute growth, growth rate, growth rate). In order to ensure further analytical forecasting of industrial product markets, the selection of an approximating curve was made using the method of trend formation. Based on the obtained logarithmic curve, a smoothed estimate of the trend was made and a forecast of world steel production for the period 2023–2027 is formed. The forecast volumes of the metallurgical industry supply markets (iron ore market (iron ore and agglomerate); limestone market, scrap market, energy market), as well as the greening market (recovered steam, converter gas, blast furnace gas) and related products (slag, dust) are determined for the period 2022–2027 The forecast indicators of the growth of markets for industrial products of the metallurgical sector are substantiated. The main principles of the international strategy for the development of the steel market are determined: efficiency and sustainability of development, designing the product life cycle, stimulating the reuse of industrial products; maximum use of scrap, acceleration of decarbonization processes and transition to green steel production, effective and efficient processing of by-products. Proposed areas of the international steel development strategy: ensuring sustainable growth; promoting the development of security markets; development of effective use of related products.

Determining the Steam Boiler Furnace Gas Temperature and Emissivity during Flame Combustion of Peat

Determining the Steam Boiler Furnace Gas Temperature and Emissivity during Flame Combustion of Peat

Ex-ante life cycle assessment of polyols using carbon captured from industrial process gas

This study presents an ex-ante life cycle assessment of a carbon capture and utilization technology that converts carbon emissions from the blast furnace gas of a steel mill to valuable intermediates for the production of polyols.

Research progress on adsorption and separation of carbonyl sulfide in blast furnace gas.

The iron and steel industry is one of the foundational industries in China. However, with the introduction of energy-saving and emission reduction policies, desulfurization of blast furnace gas (BFG) is also necessary for further sulfur control in the iron and steel industry. Carbonyl sulfide (COS) has become a significant and difficult issue in the BFG treatment due to its unique physical and chemical properties. The sources of COS in BFG are reviewed, and the commonly used removal methods for COS are summarized, including the types of adsorbents commonly used in adsorption methods and the adsorption mechanism of COS. The adsorption method is simple in operation, economical, and rich in types of adsorbents and has become a major focus of current research. At the same time, commonly used adsorbent materials such as activated carbon, molecular sieves, metal-organic frameworks (MOFs), and layered hydroxide adsorbents (LDHs) are introduced. The three mechanisms of adsorption including π-complexation, acid-base interaction, and metal-sulfur interaction provide useful information for the subsequent development of BFG desulfurization technology.

СТРАТЕГІЧНІ ПЕРСПЕКТИВИ РОЗВИТКУ СУПУТНІХ ПРОДУКТІВ МЕТАЛУРГІЙНОЇ ГАЛУЗІ В КОНТЕКСТІ ЦИРКУЛЯРНОЇ ЕКОНОМІКИ

The article examines the development of global metallurgical production within the framework of a formed circular economy system. It demonstrates that the circular economy of the metallurgical industry is based on efficient resource utilization within enterprises and adherence to stability indicators. An innovative transformation process from a linear model of the metallurgical sector to a circular economy model (a closed-loop economy) has been identified. Strategies for secondary processing, restoration, and re-production aim to extend the service life of products. The circular economy of the metallurgical sector eliminates stages of disposal and the concept of "waste." Instead, this new model relies on digital tools to enhance energy efficiency, reduce material intensity, employ decarbonization systems, and utilize by-products. The concept of 3R + co-P (reduce, reuse, recycle, co-products) has been defined, encompassing actions such as reduction, reuse, recycling, and co-products. The coproducts level involves the use of by-products (sludge, dust, slag, emulsions, used oils, technological gases, chemical substances). The reduction level is responsible for enhancing production efficiency and reducing costs. The reuse level characterizes the durability of steel, allowing for multiple product reuses after their service life. Besides extending the product's lifespan, reuse helps avoid the need for transportation and steel remelting. By-products such as converter gas, coke oven gas, blast furnace gas, and water also belong to the category of reusable resources. Melting steel scrap from products after their service life constitutes the third level of the circular economy in steelmaking production. Due to the magnetic properties of steel, it can be easily and readily extracted from almost any waste stream. Scrap metal serves as a material resource for metallurgy, preserving the resource potential of the mining sector. The article reveals the efficiency of by-products in metallurgical production and underscores their necessity for fundamental strategic sectors of the national economy (construction, mechanical engineering, chemical industry).