Preparation and Properties of SiC Assembled Large Block for Blast Furnace Tuyeres

A SiC assembled large block for blast furnace tuyeres was prepared using silicon carbide particles(3-1 and 1-0.088 mm)and fine powder(<0.088 mm),silicon powder(<0.088 mm),industrial carbon black(N990),microsilica,ρ-Al_(2)O_(3) powder,etc.as raw materials.The developed block was compared with a silicon nitride bonded silicon carbide brick,a self-bonded silicon carbide brick and an imported self-bonded silicon carbide block to analyze and evaluate their service performance.The results show that:(1)in the 0-100 mm zone,the SiC large block mainly consists ofβ-SiC and nitrides such as O'-SiAlON,β-SiAlON,α-Si_(3)N_(4),and Si_(2)N_(2)O,the bulk density is 2.68-2.70 g·cm^(-3),the apparent porosity is 14%-15%,and the material structure is uniform;(2)in the 0-100 mm zone,β-SiC nano-whiskers intercalate with nitrides;with the depth increasing,the number of flocculentβ-SiC nano-whiskers increases,while the number of nitrides decreases;when the depth reaches 150 mm or more,the main bonding phases areβ-SiC and mullite;(3)compared with the reference products,the developed SiC large block has a good basic performance,and after alkali corrosion,the mass change rate is-0.1%,which is obviously superior to the imported self-bonded silicon carbide and the homemade silicon nitride bonded silicon carbide materials.

Mechanism of zinc damaging to blast furnace tuyere refractory

The phenomena of tuyere upward-warp have been found at No.6 blast furnace in Kunming Steel Company China after its blow-in, which has made a great impact on the practical production of the furnace. Thus, a number of efforts have been made to elucidate the mechanism of this phenomenon. The results of investigation and tests revealed that the enrichment and expansion of zinc in the tuyere bricks is the main factor leading to the tuyere upward-warp. The eroding behavior of zinc is that the inner structure of the tuyere bricks turns from dense to loose with entering, enriching and expanding of zinc, which forms spot-like→stripe-like→ditch-like→vein-like→tumorlike eroding passage. Additionally, it is found that the sequence of deleterious ele- ments entering the tuyere refractory is K, Na, Zn and Pb, respectively. Finally, the phenomena and process of zinc crystallization and growth in the refractory have been clearly observed and recorded during this investigation.

Application of Ceramic Coat Synthesized by In-Situ Combustion Synthesis to BF Tuyere

A novel technology of tuyere protection is introduced. The ceramic coat .is synthesized by using in-situ combustion process as the internal, external, and nose protecting coat of BF tuyeres. It can effectively protect the tuyeres and reduce heat loss by cooling water. The technglogy is quick-acting, easy to use, energy-saving and can make tuyeres have long service life. The feasibility of the application of the tuyere ceramic coat is discussed and the energy-saving effect of the tuyere is compared with that of the tuyeres lined with refractory.

Design of Balanced Reactor Welded with Water-Cooled Aluminum Busbars

A new process of welding aluminum water-cooled busbars is proposed, It can not only reduce the weight and cost, but also improve the dynamic and thermal stability. Furthermore~ both finite element method analysis and a prototype test testify the advantages of the design which is not limited by load current and provides a new approach for water-cooled reactors.

Analysis and optimization of heat loss for water-cooled furnace roller

A heat transfer model of furnace roller cooling process was established based on analysis of furnace roller＇s structure. The complicated model was solved with iteration planning algorithm based on Newton search. The model is proved logical and credible by comparing calculated results and measured data. Then, the relationship between water flow velocity, inlet water temperature, furnace temperature and roller cross section temperature, outlet water temperature, water temperature rise, cooling water heat absorption was studied. The conclusions and recommendations are mainly as follows： l） Cooling water temperature rise decreases with the increase of water flow velocity, but it has small relationship with inlet water temperature; 2） In order to get little water scale, inlet water temperature should be controlled below 30 ℃. 3） The cooling water flow velocity should be greater than critical velocity. The critical velocity is 0.07 m/s and water flow velocity should be controlled within 0.4-0.8 m/s. Within this velocity range, water cooling efficiency is high and water temperature rise is little. If cooling water velocity increases again, heat loss will increase, leading to energy wasting.

Numerical Simulation on Subcooled Boiling Heat Transfer Characteristics of Water-Cooled W/Cu Divertors

In order to realize safe and stable operation of a water-cooled W/Cu divertor under high heating condition,the exact knowledge of its subcooled boiling heat transfer characteristics under different design parameters is crucial.In this paper,subcooled boiling heat transfer in a water-cooled W/Cu divertor was numerically investigated based on computational fluid dynamic（CFD）.The boiling heat transfer was simulated based on the Euler homogeneous phase model,and local differences of liquid physical properties were considered under one-sided high heating conditions.The calculated wall temperature was in good agreement with experimental results,with the maximum error of 5%only.On this basis,the void fraction distribution,flow field and heat transfer coefficient（HTC）distribution were obtained.The effects of heat flux,inlet velocity and inlet temperature on temperature distribution and pressure drop of a water-cooled W/Cu divertor were also investigated.These results provide a valuable reference for the thermal-hydraulic design of a water-cooled W/Cu divertor.

Investigation into characteristics of the char bed in the melter gasifier through tuyere probing

Tuyere coke probing was conducted at the Baosteel Corex Plant in order to gain a better understanding of the structure of the char bed in the melter gasifier （ MG ）. After screening, the specimens were observed by an optical microscope to determine the mechanism of the char bed formation. X-ray diffraction （XRD） was used to clarify the degree of graphitization and infer thermal history of coke. The results show that the amount of powder coming from lump coal in the burden is much more than that from coke. Based on this, measures for improving the char bed＇ s permeability are proposed.

Preparation of Al-Zn-Mg-Cu alloy semisolid slurry through a water-cooled serpentine pouring channel

The semisolid slurry of Al-Zn-Mg-Cu alloy was prepared through a self-designed water-cooled copper serpentine pouring channel(WSPC) machine. Influences of pouring temperature, the number of turns and the cooling water flow rate on the microstructure of the semisolid Al-Zn-Mg-Cu alloy slurry were investigated. The results show that the semisolid Al-Zn-Mg-Cu alloy slurry with satisfactory quality can be generated by the WSPC when the pouring temperature is in the range between 680 ℃ and 700 ℃. At a given pouring temperature, the average grain size of primary α-Al decreases and the shape factor increases with the increase of the number of turns. When the cooling water flow rate is 450 L·h^(-1), the obtained semisolid slurry is optimal. During the preparation of the semisolid Al-Zn-Mg-Cu alloy slurry with low superheat pouring, the alloy melt has mixed inhibition and convection flow characteristics by "self-stirring". When the alloy melt flows through the serpentine channel, the chilling effect of the inner wall of the channel, the convection and mixed inhibition of the alloy melt greatly promote the heterogeneous nucleation and grain segregation. This effect destroys the dendrite growth mode under traditional solidification conditions, and the primary nuclei gradually evolve into spherical or nearspherical grains.

Optimization of the Water-Cooled Structure for the Divertor Plates in EAST Based on an Orthogonal Theory

An orthogoual experimental scheme was designed for optimizing a water-cooled structure of the divertor plate. There were three influencing factors： the radius R of the water- cooled pipe, and the pipe spacing L1 and L3. The influence rule of different factors on the cooling effect and thermal stress of the plate were studied, for which the influence rank was respectively R 〉 L1 〉 L3 and L3 〉 R 〉 L1. The highest temperature value decreased when R and L1 increased~ and the maximum thermal stress value dropped when R, L1 and L3 increased. The final optimized results can be summarized as： R equals 6 mm or 7 mm, L1 equals 19 mm, and L3 equals 20 mm. Compared with the initial design, the highest temperature value had a small decline~ and the maximum thermal stress value dropped by 19~ to 24~. So it was not ideal to improve the cooling effect by optimizing the geometry sizes of the water-cooled structure, even worse than increasing the flow speed, but it was very effective for dropping the maximum thermal stress value. The orthogoaal experimental method reduces the number of experiments by 80%, and thus it is feasible and effective to optimize the water-cooled structure of the divertor plate with the orthogonal theory.

Analysis of surface cracking in water-cooled rolls and heat transfer between furnace chamber and rolls in a direct flame furnace

In the direct fired furnace of a continuous annealing line, seal rolls are susceptible to deformation that leads to surface defects of steel strips. According to failure analysis, the reasons include improper structural design and heat imbalance. An improved design has been proposed to reduce stress concentration and thermal radiation. A heat transfer model has been employed to determine the proper water flow rate for roll cooling. Industrial application proves that seal rolls with the new design has less deformation and longer service life.

Research on overall assembling and welding process of steel box girder tuyere blocks of Taizhou Bridge

This article presents in detail the assembling and welding process technique of the steel box girder tuyere blocks of Taizhou Bridge. The application of this process technique effectively solves the problem of welding stress release in tuyere block assembling and welding without increasing the number of turns of the blocks and overhead welding, thus avoiding possible structural deformation due to excessive accumulation of internal welding stress, greatly reducing the repeated deformation and correction work during assembling and welding, and ensuring the weld seam quality and overall dimensions of tuvere blocks of Taizhou Bridze.

Fully Immersing Water-Cooled Radial Slab Laser and its Incoherent Beam Combination

A novel scheme of fully immersing water cooling is proposed for a Nd：glass radial slab laser. The slab medium is entirely immersed in the circulating water Ailing the pumping cavity, which enables much lower temperature and reasonably smaller thermal gradient in the slab medium. The radial slab is symmetrically and synchronously pumped by eight flash lamps, and produces multi-output beams with a total energy of 469md. Incoherent beam combination property of the multi-output beams is also investigated. The approach suggested here provides a way of scaling the slab lasers to much higher output levels and also a convenience for beam combinations.

The Corrected Simulation Method of Critical Heat Flux Prediction for Water-Cooled Divertor Based on Euler Homogeneous Model

An accurate critical heat flux（CHF） prediction method is the key factor for realizing the steady-state operation of a water-cooled divertor that works under one-sided high heating flux conditions.An improved CHF prediction method based on Euler＇s homogeneous model for flow boiling combined with realizable k-ε model for single-phase flow is adopted in this paper in which time relaxation coefficients are corrected by the Hertz-Knudsen formula in order to improve the calculation accuracy of vapor-liquid conversion efficiency under high heating flux conditions.Moreover,local large differences of liquid physical properties due to the extreme nonuniform heating flux on cooling wall along the circumference direction are revised by formula IAPWSIF97.Therefore,this method can improve the calculation accuracy of heat and mass transfer between liquid phase and vapor phase in a CHF prediction simulation of water-cooled divertors under the one-sided high heating condition.An experimental example is simulated based on the improved and the uncorrected methods.The simulation results,such as temperature,void fraction and heat transfer coefficient,are analyzed to achieve the CHF prediction.The results show that the maximum error of CHF based on the improved method is 23.7%,while that of CHF based on uncorrected method is up to 188%,as compared with the experiment results of Ref.[12].Finally,this method is verified by comparison with the experimental data obtained by International Thermonuclear Experimental Reactor（ITER）,with a maximum error of 6% only.This method provides an efficient tool for the CHF prediction of water-cooled divertors.

Creation and Development of Turbo-generators with Water-Cooled Stator and Rotor Windings in Shanghai Electrical Machinery Mfg Works

1. An Overview of Manufacture and Operation A turbine generator utilizing a new technology of electrical machinery industry, i.e. the windings of its stator and rotor all being inner water-cooled, was first successfully created in China and was known afterwards as a turbine generator with watercooled stator and rotor windings (Abbrev, TGWSR). The teachers from Zhejiang University came to Shanghai between

高炉风口取样及风口焦特性的研究进展

风口焦炭特性研究对指导高炉操作及配煤具有重要作用。分析了目前不同风口取样方法在高炉冶炼中的应用,综述了风口焦炭粒度、矿物相、光学组织和反应性的研究现状。对今后风口焦炭取样分析进行了展望,认为风口取样分析对高炉低碳化、智能化发展具有重要意义。

首钢股份高炉喷吹生物质微粉的可行性分析

对首钢股份高炉喷吹生物质微粉的可行性进行了分析。结果表明:①河北省唐山市一年的生物质微粉产量折合约137.64万t,可满足高炉喷吹的燃料需求,生物质资源的使用成本约为877.4元/t,用于高炉喷吹具有较好的经济效益;②几种利用变压闪蒸技术制备的生物质微粉样品中,样品7最适合进行高炉喷吹,其灰分低、水分低,能量密度接近褐煤水平,但后续仍需对工艺参数进行不断优化,以提高品质;③基于1号高炉的生产参数及原燃料质量,用31.6kg/t的样品7替代10kg/t煤粉较为可行,风口热状态相较于基准工况变化较小。

风口小套上部熔损的原因分析及控制措施

基于风口小套上部熔损的理论基础,从烧毁热流出发,分析了铜的导热性对小套熔损的影响,提出了铜的纯度要求及对P含量的控制;计算了适宜的风口小套冷却水速、入口水压;分析了高炉原燃料对小套熔损的影响,着重提出了铅会加剧小套的熔损;在生产操作方面,提出控制软熔带根部不能太低,以利于减轻小套的烧损。

Optimization study of spherical tuyere based on BP neural network and new evaluation index

The energy consumption of heating,ventilation,and air conditioning(HVAC)systems holds a significant position in building energy usage,accounting for about 65%of the total energy consumption.Moreover,with the advancement of building automation,the energy consumption of ventilation systems continues to grow.This study focuses on improving the performance of spherical tuyeres in HVAC systems.It primarily utilizes neural networks and multi-island genetic algorithms(MIGA)for multi-parameter optimization.By employing methods such as structural parameterization,accurate and fast computational fluid dynamics(CFD)simulations,a minimized sample space,and a rational optimization strategy,the time cycle of the optimization process is shortened.Additionally,a new comprehensive evaluation index is proposed in this research to describe the performance of spherical tuyeres,which can be used to more accurately assess spherical tuyeres with different structures.The results show that by establishing a neural network prediction model and combining it with the multi-island genetic algorithm,a novel spherical tuyere design was successfully achieved.The optimized novel spherical tuyeres achieved a 27.05%reduction in the spherical tuyeres effective index(STEI)compared to the traditional spherical tuyeres.Moreover,the resistance decreased by 15.68%,and the jet length increased by 7.57%.The experimental results demonstrate that our proposed optimization method exhibits high accuracy,good generalization capability,and excellent agreement at different Reynolds numbers.

高炉风口喷吹煤粉的燃烧模拟研究

为了减少高炉炼铁过程的焦比,现代高炉通过风口喷吹煤粉代替部分焦炭。以某高炉的设计参数与生产数据为模拟条件,建立高炉风口回旋区喷吹煤粉燃烧的三维模型,对直吹管、煤粉喷枪、风口、回旋区、焦炭床等高炉下部区域的煤粉燃烧现象进行模拟研究,并结合该高炉提供的生产数据验证模型的可靠性。模拟结果显示,热风离开风口进入回旋区,最大速度达到257m/s,之后不断减小。煤粉进入高炉后,挥发分在回旋区内距离风口截面0.4m处开始析出,在回旋区内距离煤粉喷枪1m处形成2600K的高温区域。部分粒径大于70μm的煤粉在回旋区内未完全燃烧,就进入焦炭床并沿炉缸中心向上运动,燃尽率过低,影响高炉透气性。

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.