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.

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.

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.

Measures to dealwith low strength coke for Basteel's 2500 m^3 BF

The production indexes were deteriorated due to quality coke,Utilization Factor 2.0 t/m^3·d,PCI 100 kg/T,According to Analysis the Mechanism of Production of low hot strength coke quality on Blast Furnace Smooth,The coke cold strength retained M_(10)<6.3 over a long period of time in order to insure coke granularity and permeability index in cohesive zone;A_(ad)<12 and granularity tranquilization is useful BF production.The PCI protect coke hot strength by high rate bituminous coals;high rate H_2 in BF gas bate coke demolish.blast furnace operation,on monitoring and operation BF,tranquilization the BLAST FURNACE temperature,PT controls parameter area is about 1 500℃;strengthen management of permeability index, improve Top - pressure for Blast Furnace,Strengthening the Management of the Raw Materials and Fuel, logical rate of sinter Level off about 70%to improve Metallurgical Properties of Burdens.Parameters of wind have been adopted About 10 000 - 11 000 kg·m/s;,theoretical flame temperature in a blast furnace have been adjusted area is about 2 050 - 2 200℃;the temperature direction about copper stave management established act;according to this measures,According to Improvement Center Gas Flow Instability in the first place,the gas flow distribution turns to the reasonable state.Strengthen furnace casthouse operation ect, Utilization Factor improve 2.2 t/m^3·d,PCI 130 kg/T.Cold and hot state strength indexes of coke on BF production were instability.According to optimize the Operating Paramete in specifically economy technology indexes conduction,the BF condiction can keeping steady and smooth.

Hot Blast Flow Measurement in Blast Furnace in Straight Pipe

This article shows an innovative method to model and validate the hot air flow through the blast furnacés tuyeres. This study will be the basis for flow measurements implementation and safety interlocks for the pulverized coal injection. The flow measurements were taken in the blast furnace down leg pipes by installing refractory Venturi tubes. The system for the calculation of differential pressure takes into consideration the dimension of the Venturi, the air density and compressibility. The objective is to specify the flow transmitters required to automate a control system and implement safety interlocks for the coal injection plant.

Interaction mechanism between coal combustion products and coke in raceway of blast furnaces

The interaction mechanism between the combustion products of pulverized coal injected and coke in the raceway of blast furnace was studied through thermodynamic calculation and experiments.The results indicated that additives significantly affected the melting property of coal ash in high temperature zone.Although the unburnt char,raw coal ash,and catalyzed coal ash failed to wet the coke surface,the wettability of the catalyzed coal ash on the coke was greater than that of the raw coal ash.Since the unburnt char had weak reaction with the coke surface,it showed little influence on the surface morphology of the coke.The interaction between the raw coal ash and the coke gave rise to the increase in the pore size on the coke surface.However,the raw coal ash only affected the coke surface and the entrances of the pores owing to its poor fluidity.After being melted,the catalyzed coal ash was expected to immerge into the inside part of the coke and then react with the coke,resulting in an expansion and increase of coke cavities.The raw coal ash and the unburnt char reduced the coke reactivity,while the catalyzed coal ash improved the coke reactivity.Thereinto,the coal ash containing Fe2O3 exhibited a larger influence on the reactivity than that containing CaO.

When Lotus Leaves Prevent Metal from Melting一Biomimetic Surfaces for High Temperature Applications

Functional properties of biological surfaces have gained increasing interest in the last two decades,especially with regard to wetting and sei-cleaning.Here,biological surfaces of arthropods(Collembola)and plants(sacred Lotus)served as models for the principle design of high temperature resistant surfaces used in blast furnaces to prevent tuyeres from melting.Tuyeres are double-walled,watercooled pipes supplying the blast furnace with hot air to keep the reduction and melting process running.Tuyere failure is mainly caused by melting of the wall after direct contact with liquid iron,resulting in the partial shut down of the blast furnace and huge energy losses.As a new approach to avoid tuyere failure we developed a new type of tuyere surface with(i)defined cone shaped indentations and(ii)a heat resistant zirconium/corundum coating with"ferrophobic”properties i.e.it forms with liquid iron of 1500°C a contact angle exceeding 130°.Theoretical considerations indicate that liquid iron infiltrates these indentations only partially if this contact angle and the aperture angle of the cone satisfy an inequality condition.Since heat conductivity of the remaining gas trapped inside the cones is by five orders of magnitude lower than in copper,the overall heat flow into the tuyere is substantially reduced and the outer walls are much less prone to melting.

Three-dimensional numerical simulation of flow and splash behavior in an oxygen coal combustion melting and separating furnace

The change of bubbles and the position of the tuyere in an oxygen coal combustion melting and separating furnace affect the flow and splash behavior of the molten pool.To analyze this problem further,a three-dimensional numerical simulation method was used to explore the behavior and change of the flow field inside the molten pool during double-row tuyere injection.In addition,the arrangement of the tuyere was changed for a more detailed understanding of the internal phase distribution and splashing in a molten pool.The results indicated that under three-dimensional numerical simulation conditions,bubbles rise after leaving the tuyere and break on the surface of the molten pool,which results in certain fluctuations in the nearby melt.During the injection process of the tuyere,the meteorological accumulation in the middle part of the molten pool formed part of the foam slag because of the influence of surface tension.When the layout of the upper and lower exhaust tuyeres was changed from staggered to symmetrical,or when the spacing of the upper and lower exhaust tuyeres changed,it had an effect on the phase distribution and splash behavior.