Lance Tip Research Articles

Combustion Behavior of Supersonic Jet for Single‐Flow Postcombustion Oxygen Lance with Various Secondary Nozzle Parameters

A 3D model is established to discuss the influence of combustion reaction on jet characteristics. Based on this, combustion behaviors of supersonic jet for single‐flow postcombustion oxygen lance with various secondary nozzle parameters (diameter, inclination angle, and number) are analyzed. The results indicate that after activating combustion reaction, the jet velocity, dynamic pressure, density, and temperature of primary jet at H = 1.45 m are 1.27, 1.15, 0.56, and 1.97 times than those of without considering the combustion, respectively. Enlarging secondary nozzle diameter is helpful to extend the flame core lengths of primary and secondary jets (the axial distance from lance tip to isotherm of 1773 K) as well as the combustion region. With the increase of secondary nozzle angle, the two flame core lengths both decrease, while the combustion zone increases. Increasing the number of secondary nozzles, the flame core length of primary jet increases while that of the secondary jet decreases, and the combustion region first increases and then decreases. As for the influences of the above parameters on flame core lengths of primary and secondary jets as well as the combustion region, the number is the greatest, followed by the inner diameter, and the inclination angle is the smallest.

Numerical simulation of the effect of coaxial and cross-axis injection modes on pulverized coal combustion in the raceway of blast furnace tuyere

The aim of this study is to investigate the influence of the angle of the pulverized coal (PC) injection lance on the combustion characteristics of fuel in the raceway of blast furnace tuyeres. Using FLUENT software, a Euler-Lagrange three-dimensional numerical model was constructed to analyze the influence of different positions of blast furnace tuyere coal powder injection lance (coaxial and cross-axis) on key parameters such as temperature distribution, gas flow, and combustion efficiency. The results demonstrate that adjusting the angle of the injection lance significantly modifies the average and peak temperatures in the raceway, while the composition of gas components remains relatively stable. When the injection lance angle is 10°, the average temperature and peak temperature in the raceway are 2294 K and 2747 K, respectively. When the injection lance angle is 12°, the combustion efficiency of the PC reaches 80.8%. This study reveals the significant impact of the injection lance angle on the combustion process. Especially at an angle of 12°, the combustion efficiency of the blast furnace significantly improves. With coaxial injection, the combustion rate increases as the distance between the injection lance tip and the tuyere increases. This paper is instructive for the optimization of the blast furnace combustion system, which improve fuel utilization efficiency and reduce environmental emissions. This paper provides practical recommendations for adjusting blast furnace operational parameters, offering insights for achieving more efficient and environmentally friendly industrial production.

Analysis of Effectiveness of Bottom Stirring after the Modernization on Basic Oxygen Furnace in HBIS Serbia Group

The significant modernization effort in the steel shop at HBIS Group Serbia is the introduction of a Basic Oxygen Furnace, which features bottom stirring with argon and nitrogen, along with the capability for slag splashing with nitrogen through the lance tip after steel tapping from the converter. Implementing this new technology presented a challenge, as it was our first encounter with such advancements. The primary objectives of this modernization were to achieve a lower dissolved oxygen content in steel while reaching the targeted carbon level at the end of the blowing process. This aims to optimize the steel's oxidation degree [%C] [%O], reduce the use of Al as a deoxidizer, increase yield, and achieve a low phosphorus content in steel at the end of blowing. Additionally, it aimed to increase the lining's lifetime through slag splashing and decrease the refractory mass consumption needed for lining repairs. This analysis covers a 7-month period since the start of the campaign with the new refractory lining, based on research conducted on 3,150 heats. Our examination of the process led us to conclude that while certain parameters met our expectations, some results did not reach the anticipated level.

OPERATING CONDITIONS AND STABILITY FIRE RESISTANT LINING SUBMERGED LANCE

To ensure the reliable and long—term operation of submersible lances used in the processes of bucket desulfurization of cast iron before converter processing, reliable means and appropriate conditions for supplying powdered desulfurizing reagents through nozzles of the lance tip, a rational scheme of refractory lining of the submersible lance and improvement of its operation modes are necessary. The purpose of the work is to study the characteristics of the destruction of the refractory lining of submersible lances, intended for desulfurization of iron—carbon melts by blowing powdery reagents deep into the ladle bath. To realize the goal, we used practical information on the researched question and the method of isothermal modeling of the hydrogas dynamics of a bucket bath using variable designs of the tips of stationary and rotating submersible lances. A comparative analysis and study of the features of the destruction of the lining of submerged stationary and rotating lances in the area of contact with the metal melt (below the "slag—metal" border) during gas injection into the bath was carried out using a 230—t pouring ladle model. During the experiments, T—shaped tips were used (for rotating and stationary lances) and tips with two spray pipe placed at an angle of 45 degrees to the axis of the lance (for stationary lances). Based on the results of data processing, mathematical models were obtained for each of the isolated zones on the lining surface of the submersible lance, and the statistical significance of the sample regression coefficients was checked. The nature and features of the destruction of the lining layer in each of the zones corresponding to the changes in the bath blowing conditions were established. New data were obtained regarding the intensity and depth of wear of the lining of the rotating submersible lance, depending on its speed of rotation and carrier gas consumption. It was established that under the investigated conditions of blowing the bath, the speed of rotation of the lance can be attributed to the factor most influencing the depth and intensity of wear of the lance lining.

A Review of Top-Submerged Lance (TSL) Processing—Part I: Plant and Reactor Engineering

Part I of this series of papers focuses on plant and reactor engineering aspects of the TSL reactor technology. A general flowsheet is presented, while emphasis is given to the definition of different reactor zones in terms of fluid dynamics and occurring reactions. Then, the technical advantages of TSL processing, such as feed flexibility and high conversion rates (due to induced turbulence), low dust generation, and low fugitive emissions, are explained. In addition, the reactor is analyzed part by part, also taking into account patent literature, focusing on furnace design, settling furnaces for molten phase disengagement, feeding systems regarding input material streams such as concentrates and fuels, vessel cooling arrangements, off-gas system, and aspects associated with the refractory lining. Furthermore, specific focus is given to the centerpiece of the TSL reactor, i.e., the reactor lance. Associated developments have focused on establishing a slag coating to hinder lance wear, i.e., the development of cooling mechanisms (e.g., use of fluid-cooled lance and shroud arrangements), the increment of O2 enrichment within the incoming air stream, and influencing of fluid dynamics (e.g., O2 conversion at the lance tip, bubble formation, and bath splashing). Finally, comprehensive tables concerning process developments and commissioned TSL plants are provided thus concluding Part I of the review.

Transient simulation of heat and mass transfer in a parallel flow regenerative lime kiln with pulverized coal injection

Quicklime, which is an essential raw material in various industries, is primarily produced by thermally calcinating limestone in kilns. Among the various kiln designs, parallel flow regenerative (PFR) kilns with pulverized coal combustion are the predominant technology. The performance of the PFR kilns is determined by the interactions between the gas, limestone, quicklime, and coal particles inside the chamber. Additionally, the two chambers in the PFR kiln alternate after a short period during the operation. Consequently, the transfer behaviors between the various phases inside the chamber are in a transient state. A three-dimensional transient multiphase model was created to investigate the transient multiphase behavior. The entire operation cycle, which consists of calcination and regeneration processes, was simulated using a coupling method. The predicted CO2 concentration in the exhaust gas was compared with the industrial measurement data, and good agreement was obtained, with an error of less than 6%. Furthermore, variations in the gas and limestone temperatures and limestone concentrations with residence time during each period were obtained. During the calcination period, the gas temperature field stabilized after 100 s. After stabilization, the zone where intensive limestone decomposition occurred was located in the range 0–5 m from the lance tip. The maximum gas temperature in the calcination process was 1845 K, which was approximately 700 K higher than that of a PFR kiln fueled with natural gas. CO2 gradually accumulated in the middle part of the chamber; the average concentration of CO2 in the off-gas was 27.7%. In the regeneration period, the transfer process stabilization required 400 s. Furthermore, the maximum gas temperature was higher than that of a PFR kiln fueled with natural gas, with a difference of approximately 90 K. Contrary to the calcination period, CO2 accumulated in the peripheral region at the end of regeneration. The total CO2 emission is 1.2024 t CO2/t product for the investigated coal-fueled PFR kiln. These transient transfer characteristics, during the PFR operation, could aid the optimization of coal utilization and control of CO2 emissions in the future.

Research on the Jet Characteristics and Dephosphorization Efficiency of Converter Oxygen Lance Blowing CO2-O2 Mixed Gas

Utilization of CO2 in steelmaking process has attracted extensive attention in recent years, not only because of its social benefits, but also its better metallurgical performance. Mixing CO2 with O2 blown by converter oxygen lance is gradually being adopted by steelmaking plants, due to its potential of reducing consumption and improving steel quality. In the present research, effect of mixing CO2 on the jet characteristics of a four-nozzle oxygen lance was studied in detail by numerical simulation, taking the combustion behavior between supersonic jets and ambient atmosphere into consideration innovatively. The simulated results showed that the combustion flame is mainly distributed in the region between multiple jets, and the high temperature flame has a noticeable influence on the low-velocity region of the jet. Due to the dilution effect of CO2, mixing CO2 into the oxygen jets will reduce the maximum temperature of the flame and slow down the combustion rate. With the increase of CO2 mixing ratio, the high-temperature zone of combustion flame moves away from the lance tip significantly. At the same distance from the nozzle, although mixing CO2 can hardly increase the velocity magnitude of the jet, but it can achieve higher dynamic pressure, indicating stronger impacting power. Then the industrial experiment of top blowing O2-CO2 was carried out in a 120-ton converter. During the blowing time of 120~300 s, the mixing ratio of CO2 was 15 vol.% for better dephosphorization, and no CO2 was mixed in the rest time of blowing. Due to the stronger stirring and better thermodynamics, the average [P] content in the final molten steel was decreased from 0.0155 wt.% to 0.0129 wt.%, achieving higher dephosphorization efficiency.

Corrosion damage and in-service inspection of retractable sootblower lances in recovery boilers

Several reports of accidents involving serious mechanical failures of sootblower lances in chemical recovery boilers are known in the pulp and paper industry. These accidents mainly consisted of detachment and ejection of the lance tip, or even of the entire lance, to the inside of the furnace, towards the opposite wall. At least one of these cases known to the author resulted in a smelt-water explosion in the boiler. In other events, appreciable damage or near-miss conditions have already been experienced. The risk of catastrophic consequences of the eventual detachment of the lance tip or the complete lance of a recovery boiler soot-blower has caught the attention of manufacturers, who have adjusted their quality procedures, but this risk also needs to be carefully considered by the technical staff at pulp mills and in industry committees. This paper briefly describes the failure mechanisms that prevailed in past accidents, while recommending inspection and quality control policies to be applied in order to prevent further occurrences of these dangerous and costly component failures. Digital radiography, in conjunction with other well known inspection techniques, appears to be an effective means to ensure the integrity of sootblower lances in chemical recovery boilers used in the pulp and paper industry.

Effects of single lance configuration on coal combustion process in tuyere from viewpoint of coal plume

Pulverized coal utilization in the blast furnace is decided by the particle flow and combustion behaviors in the raceway. Under a specific operating condition, these behaviors are directly related to the lance configuration in the upstream tuyere zone. Focusing on single straight lance, six types of single lance configurations were designed by assembling four parameters in different ways. These four parameters are the lance diameter, lance insertion angle, and the horizontal and vertical distances from the lance tip to the tuyere tip. With different lance configuration schemes applied, the pulverized coal combustion process in the lance–blowpipe–tuyere zone was simulated. The simulation results regarding particle diffusion and combustion behaviors were characterized by three indicators from the viewpoint of a coal plume. They are the plume diffusion angle, diffusion uniformity, and the average plume temperature at the tuyere outlet. To promote coal utilization, the values of these indicators under different configurations were analyzed, yielding two optimal configurations. The first one is to reduce the lance length immersed in the blowpipe–tuyere by 100 mm. The other is to increase the horizontal distance from the lance tip to the tuyere outlet by 50 mm, and the insertion angle to 11° with the lance tip located at the tuyere centerline. The findings can enhance the understanding of the influence mechanism of lance configuration on the coal utilization and provide guidelines for the design of new lance configurations.

Physical and Mathematical Modeling of Swirling Gas Jets Impinging onto a Liquid Bath Using a Novel Nozzles‐Twisted Lance

Physical and mathematical modeling is performed in a 10:1 scaled‐down basic oxygen furnace (BOF) steelmaking vessel to study impingement onto a bath of swirling gas jets from a novel nozzles‐twisted lance. The particular aspects with respect to the swirling jets‐induced cavity characteristic, jets’ stirring efficiency, and bath flow field are focused upon, and their discrepancies with those created by conventional oxygen lance jets are assessed. Results show that compared with the conventional jets, the swirling jets strike a greater impact area with a shallower but wider cavity and facilitate bath surface flow. Due to a more intensive bath horizontal flow, which shows an increase in intensity by 0.34–1.66 times than that of conventional jets, the swirling jets shorten bath mixing time by 11–60%, depending on the nozzle twist angle of the lance. These results suggest that the lance height of the nozzles‐twisted lance is operated more flexibly than that of the conventional one. This not only enables sufficient bath stirring efficiency and improves slagging but also contributes to postponing lance tip erosion and prolonging its life span in plant operations, whereas the enhanced flows in the regions near the sidewall accelerate refractory erosion there.

Effect of Lance Structure on Behavior of Coherent Jet in EAF Steelmaking Process.

During the electric arc furnace steelmaking process, the coherent jet technology was widely used to protect the kinetic energy of the supersonic oxygen jet and achieve better mixing effects. Comparing with the conventional oxygen lance, the coherent lance could increase the surface area of impaction cavity, resulting in a better stirring effect and higher reaction rate. However, there was limited research about the effect of restriction structure for the coherent lance tip on the flow field characteristic of the main oxygen jet. In this research, three kinds of restriction structures have been investigated by numerical simulation and combustion experiment at room and high ambient temperature conditions. Then an optimum restriction structure would be tested in a 75 t electrical arc furnace steelmaking process to verify its metallurgical property.

Study of the features of interaction of gas jets with liquid bath at top blowing through an annular coaxial nozzle

Technological, technical and economic indicators of BOF heat largely depend on the organization of the blowing mode. Under the current conditions of instable supply and the quality of charge materials and energy carriers, as well as the need to increase the intensity and quality of the blowing process, the studies on developing new design of tip for oxygen lance, the base element of it being a composite annular coaxial nozzle. The studies were carried out on “cold” physical models and on models of BOF convertor with hot metal. Comparative analysis of the interaction of oxygen jet with a liquid bath, using an annular coaxial nozzle (the experimental tip), and a tip having four nozzles (the comparative tip) were accomplished. It was determined, that the jet from experimental tip has a higher dynamic pressure and depth of penetration into the liquid melt without increased metal splash. While blowing through the lance with the experimental tip, a “hard” blowing pattern with the formation of a smaller amount of slag were observed. The “hard” nature of the blowing was eliminated due to the additional lateral cylindrical nozzles. As a result of the changes more active absorption of lime than at comparative heats was reached. It was revealed that the use of the perfected experimental lance tip contributes to a higher bath heating and a decrease of dust emission.

Computational Fluid Dynamics Study on a Top-Blown Smelting Process with Lance Failure in an Isa Furnace

The Isa/Ausmelt smelting technology with a top submerged lance (TSL) has been extensively used in copper smelting processes. However, the TSL is extremely vulnerable to damage and failure because of bending and tip burning. Frequent lance replacement is time-consuming and limits the copper production capacity. Here, a numerical simulation method is used to study the influence of lance failure on the flow field, splashing of slag, and wall shear of the lance as well as furnace body for exploring the factors that limit the service life of the lance. The simulation results reveal that the fluid flow is weak on the reverse bending side, which is is not conducive to mixing of raw materials when the lance is bent, resulting in a significant amount of slag splashing. After the lance tip is burned out, the utilization of agitation energy decreases because of an increase in the lance outlet area, resulting in poor stirring of the molten bath and a considerable loss of heat. In addition, this study shows that the lance wall shear varies because of slag splashing, implying that the wall shear can be reduced by reducing slag splashing.

Effects of post combustion temperature on the wear of the supersonic nozzles in BOF lance tip

Abstract This paper studies the influence of post-combustion on supersonic lance tip nozzles wear for an 80t converter, using CFD (Computational Fluid Dynamics) simulations. These analyses were based on flow profile determination of supersonic jet at minimum and maximum operation flow rates, where it could be verified post-combustion inside the nozzles at lowest flow rates. Additionally, thermal input generated by post-combustion was exported as heat flow in order to serve as a boundary condition in CFD thermal exchange simulations, also considering nozzle internal cooling. With these simulations, it was shown that copper actually reaches its melting point, at which the lowest operating flow allows post-combustion inside the nozzle. The temperature distribution profiles and the high temperatures found were also relevant for a considerable grain growth found in the wear region, according to metallographic analyses. It was thus concluded that wear occurs due to the progressive melting of copper after continuous heats with low oxygen flow rates; post-combustion inside the nozzles is the root cause for this failure.

Estudio metalúrgico de las armas ibéricas halladas en el valle de Jutia (Nerpio-Yeste, Albacete). Trabajo, armamento, ritual y comunidades de montaña

Presentamos un estudio metalúrgico de las armas de época ibérica documentadas en el valle de altura de Jutia (Nerpio-Yeste, Albacete) integrado en el análisis de su contexto arqueológico y en nuestra investigación en curso de las formas de organización de los paisajes de montaña durante la Edad del Hierro. Los resultados obtenidos son especialmente válidos en el caso de un soliferreum, cuyo análisis metalográfico nos permite caracterizar la tecnología del proceso de producción, y en el de una moharra de lanza, cuyo análisis plantea argumentos sobre la compleja vida social y las acciones sociales diversas que potencialmente contienen los objetos depositados en contextos rituales y funerarios.

Novel approach to Zr powder production by smooth ZrCl4 bubbling through molten salt

A reduction process using ZrCl4 bubbles as a reactant was investigated to produce zirconium metals. ZrCl4 vapor was bubbled through the lance in the bath, in which Mg melt and MgCl2 salt were separated. Zr powder was formed by a reduction of ZrCl4 bubbles in magnesium layer. However, the lance was clogged by the aggregate of zirconium occurred during ZrCl4 vapor injecting leading to interruption of ZrCl4 supply into the bath. This phenomenon could be caused by the presence of magnesium at the lance tip, which passes through MgCl2 salt during bubbling, and then zirconium was formed in the forms of intermetallic compounds with aluminum. In this study, the effect of molten salt on the troubled phenomena was investigated and it was verified that CaCl2 with relatively low Weber number meaning relatively high surface tension as molten salt is effective in inhibiting the lance clogging phenomena. Then, a few micrometer-sized Zr powder with the high purity of 91.6 wt% was obtained smoothly without the formation of intermetallic compound.

NUMERICAL MODEL OF FRICIONAL DAMPER FOR GLAS-MAKING ROBOT LANCE

The need to design a friction damper for glass-making robots arose because of the excessive vibrations, which occur in the course of their work. The robots are commonly used in the manufacture of glassware. The vibrations adversely affect the work of ball gatherers, which results in a large number of defects in the finished glass products. As a result of the vibrations molten glass may become unevenly distributed on the ball’s surface and as the material flows down the ball into the mould the thermal conditions of its solidification may change. It is proposed to damp the vibrations by means of a prototype friction damper mounted directly on the ball gatherer lance. The glass-making robot lance with the friction damper was modelled. The vibrations of the glass-making robot lance tip under static load and impact excitation were measured during simulations. Also the relative displacements of the damper rings in the course of the excitations were measured. Moreover, the dependence between the preload force and the system’s damping decrement was determined. The main aim was to select proper operating parameters for the proposed structure in order to obtain maximum system damping.

Study of design parameters affecting the motion of DNA for nanoinjection

This paper reports the effects of various parameters on the attraction and repulsion of DNA to and from a silicon lance. An understanding of DNA motion is crucial for a new approach to insert DNA, or other foreign microscopic matter, into a living cell. The approach, called nanoinjection, uses electrical forces to attract and repel the desired substance to a micromachined lance designed to pierce the cell membranes. We have developed mathematical models to predict the trajectory of DNA. The mathematical model allows investigation of the attraction/repulsion process by varying specific parameters. We find that the ground electrode placement, lance orientation and lance penetration significantly affect attraction or repulsion efficiency, while the gap, lance direction, lance tip width, lance tip half-angle and lance tip height do not.

Implementation of Lance Control in Top-Blown Copper Smelting Process Based on DCS

Top-blown furnace is known to be effectively adopted in copper smelting. This paper elaborates lance control strategies in top-blown smelting process based on the real project named KUNPENG COPPER SMELTER in China. We implement lance control by using several schemes, such as auto lower, auto raise, normal raise and emergency raise; meanwhile, we propose a method of auto creep control to stabilize tip pressure of lance. Moreover, the configuration of the smelting control system based on Emerson DeltaV is introduced. The result reported clearly shows that the lance rises and falls automatically according to specific conditions, as well as the lance tip pressure is stable and creep movement is precise and responsible.

Implementation of Lance Control in Top-Blown Copper Smelting Process Based on DCS

Top-blown furnace is known to be effectively adopted in copper smelting. This paper elaborates lance control strategies in top-blown smelting process based on the real project named KUNPENG COPPER SMELTER in China. We implement lance control by using several schemes, such as auto lower, auto raise, normal raise and emergency raise; meanwhile, we propose a method of auto creep control to stabilize tip pressure of lance. Moreover, the configuration of the smelting control system based on Emerson DeltaV is introduced. The result reported clearly shows that the lance rises and falls automatically according to specific conditions, as well as the lance tip pressure is stable and creep movement is precise and responsible.