喷煤对COREX熔融气化炉风口前理论燃烧温度的影响

 风口前理论燃烧温度是衡量熔融气化炉风口前热平衡和预测炉缸热状态的重?问弧Ｒ谰菘悸荢iO2还原的理论燃烧温度计算公式,分析了在熔融气化炉喷煤对风口前理论燃烧温度的影响。计算了不同喷煤条件下,熔融气化炉风口前的理论燃烧温度。在此基础上讨论了喷煤比、挥发分及焦炭(半焦)进入燃烧区域的温度等参数的影响,为选择适合COREX熔融气化炉喷吹煤提供了必要的依据。     

风口取样装置在攀钢的应用

通过对高炉风口取样装置取出的焦炭的粒度、热性能、灰成份、碱金属含量的分析研究,分析结果表明,攀钢高炉风口回旋区长度约为2m,高炉风口回旋区沿径向上,焦炭灰分、碱金属、热性能都先变小后变大。随着喷煤量的增大,风口焦的平均粒度变小,回旋区缩短。     

基于T-S模型的高炉喷煤协同优化控制策略研究

高炉炼铁过程通过增煤减焦实现节能减排目标,针对人工操作模式存在主观性、粗糙性和滞后性难以实现增煤减焦的问题,采用上下协同优化控制方法,一方面通过上部提前匹配减焦方式维持高温区热平衡,另一方面通过富氧鼓风保证下部喷入煤粉的高消化率,使煤粉在风口回旋区充分燃烧.进而从控制角度解析描述增煤减焦过程,将铁水温度的稳定控制问题转...     

高炉炉缸活性度初步研究

文章通过炉前风口焦取样分析,直观地确定了风口回旋区长度、以及喷吹煤粉燃烧率,对包钢高炉炉缸活性度研究以及提高煤粉的喷吹量研究有非常重要的指导作用。     

高炉大量喷吹煤粉的探讨

通过煤粉燃烧研究成果和喷煤实践的分析得出如下初步认识：煤粉在高炉风口区燃烧过程与一般工业炉不同，因风速高，煤粉停留时间短，煤粉在风口前端很难达到较高燃烧率；氧煤枪对延长煤粉停留时间的作用有限，据国内外多数大喷煤量高炉的实践，２００ｋｇ／ｔ以下喷煤量不一定要使用氧煤枪，风口未燃煤粉并不可怕，因其气化率比焦炭高若干倍，能优于焦炭参加还原反应，有利于改善矿石高温性能，减少焦炭粉化和高炉顺行，粒煤具有节约     

武钢高炉经济性喷煤研究

为了使武钢高炉达到经济性喷煤的目标,通过煤资源调查,掌握了适合武钢喷吹用煤的煤源情况;通过对高炉大煤比条件下的风口理论燃烧温度进行计算,分析了影响高炉喷煤的主要因素;通过对武钢高炉炉尘中的残碳量及其来源进行分析,发现目前操作条件下炉尘中源自煤粉的碳量占总碳量的10%左右,此结果已用于研究未燃煤粉在炉内的利用状况及评估高炉喷吹煤粉的燃烧情况;通过对高炉操作指标进行统计分析,发现煤比在160~170 kg/t时,高炉燃料比较低。实践结果表明,上述经济性喷煤技术在5号高炉应用后,在煤比仅略增加0.8 kg/t的情况下,焦比降低了9.7 kg/t。     

我国高炉喷煤技术的发展

论述了我国高炉喷吹煤粉技术的发展过程,分析了提高高炉喷煤比的措施,通过提高焦炭质量、改善鼓风质量、采用氧煤喷吹、混合喷吹等技术和工艺措施可有效提高喷煤比。同时指出,研究回旋区条件下煤粉的燃烧过程,开发高效喷煤助燃剂,最大限度地提高煤粉在风口区域的燃烧率和喷煤置换比,是当前喷煤技术攻关的课题。     

高富氧喷煤对高炉冶炼影响的分析

 通过分析高富氧喷煤后焦炭在高炉中的作用及炉内冶炼参数的变化,在富氧、喷煤、风温、装料制度、上下部调剂等方面合理配合条件下,可提高煤粉燃烧率,维持较高的风口理论燃烧温度,减少炉腹煤气量,提高生产效率。高富氧喷煤达到焦比和煤比各占一半时,焦炭量能够满足直接还原和渗碳需求。为了满足焦炭骨架作用,需要使用反应性差和耐磨性好的焦炭。     

重新认识高炉用焦炭与CO2的反应性

简要介绍了现行焦炭反应性试验方法的来源,主要表达焦炭在高炉内进入风口回旋区前抗CO2,气化能力以及反应后的抗粉化能力,是一种规范性试验方法。回顾了国内外对焦炭反应性的认识和变化,20世纪认为反应性表达焦炭在高炉抗CO2,的气化能力,反应性高反应后强度低对高炉生产不利。进入21世纪,新日铁提出反应性只是表达了焦炭的活性,认为提高反应性可以提高高炉反应效率,对高炉生产有利,不同时期认识水平不同认知也会完全相反。通过CO2,含量和反应温度对焦炭反应性影响试验和高炉碳平衡计算,分析了喷吹煤粉高炉内焦炭的行为．确定了焦炭进入风口回旋区前的反应失重率。提出现行国家标准“焦炭反应性及反应后强度试验方法”的反应性表达的是焦炭与CO2,反应的活性,高炉内焦炭反应失重率控制因素是矿石的还原性能和未燃煤粉率,与焦炭实验室测定的反应性无关。     

富氧喷煤对高炉风口回旋区特征影响的理论研究

运用热力学软件FactSage,针对攀钢4号高炉,研究了富氧和喷煤的变化对高炉风口回旋区特征的影响,主要是对理论燃烧温度以及煤气成分的影响。其结果表明:在攀钢目前的冶炼条件下,4号高炉的喷煤比可以继续提高至185 kg/t,但在245 kg/t时达到极限。提高喷煤比和富氧率均可提高回旋区的温度,但喷煤比的效果会更加显著;喷煤比和富氧的变化对煤气成分影响也各不相同。     

Cold Model Study of Coal Gas Component Concentration Distribution in Blast Furnace Raceway

 Primary distribution of coal gas in blast furnace raceway has an important effect on combustion of coke and pulverized coal injection, as well as whole ironmaking process. According to practical production parameters of No. 5 blast furnace in Chongqing iron &; steel Co. LTD, the theoretical calculation model recommended by Nomura is adopted to determine penetration depth, height and width of raceway. Three-dimensional cold model of blast furnace raceway is established. Coal gas component concentration distribution of vertical section and cross section in blast furnace raceway is simulated using natural gas.     

Industrial Practice of BiPCI Process of Pulverized Coal Injection for Blast Furnace Ironmaking at SSAB

BiPCI technology of pulverized coal injection for blast furnace ironmaking was applied to No.2 Blast Furnace of SSAB Oxelösund in Sweden, and notable effectiveness of this BiPCI practice at SSAB has been achieved. The results show that if the tuyere injection rate of pulverized coal is kept nearly unchanged, (1) BiPCI can increase the overall coal rate and decrease the coke rate. When the second injection rate of pulverized coal attains 5 kg/tHM, the coke rate could be reduced by 5 kg/tHM; (2) BiPCI can increase the burden permeability, decrease the pressure drop of the furnace, and produce proper gas flow distribution, which is favourable to keep smooth running of the blast furnace and decrease the total reducing agent rate (RAR). During the test, the RAR showed a decrease by 2.8 kg/tHM (corrected RAR by 1.45 kg/tHM); (3) The pulverized coal through the second injection can be effectively used to protect the coke from fast degradation and improve the coke strength in the blast furnace, which is favourable to lower the high requirement on the coke quality under high coal rate operation.     

Carbon type differentiation technique for diagnosing pulverised coal injection efficiency

Coal injection is a common practice for coke replacement in current blast furnace (BF) operations. The amount of coal that can be injected and successfully replace large coke is determined by the extent of coal gasification, which is a function of both the combustion environment in the tuyere/raceway region and combustibility of the injected coal. A new carbon type differentiation (CTD) technique was developed at CanmetENERGY for quantifying the amount of unburnt pulverised coal injection (PCI) residue that is carried in the furnace top gas for diagnosing the extent of injected coal gasification. This technique utilises the combustion characteristics of solid carbonaceous material generated during rapid pyrolysis and partial combustion of coal. The CTD technique developed was transferred to ArcelorMittal Dofasco and successfully implemented in the industrial environment. Using this technique, AM Dofasco established a PCI efficiency baseline for each of its three BFs, which will be used as a reference point for comparison in future trials. The capability of the CTD technique in diagnosing and understanding the effect of BF operating parameters on PCI burnout efficiency was demonstrated upon examining the effect of blast temperature decrease during a recent BF stove repair.     

高煤比条件下高炉风口前现象的取样研究

阐述了宝钢应用风口取样技术,对高炉在高煤比冶炼条件下风口前现象、焦炭劣化、煤粉燃烧、炉芯透液性等重要问题的研究成果.这些结果对监控焦炭质量、指导炼焦配煤、提高喷煤效果、延长炉缸寿命具有重要意义和技术价值.     

Numerical Analysis of Pulverized Coal Combustion inside Tuyere and Raceway

The process of pulverized coal combustion inside the tuyere and raceway plays a very important role in the performance of a blast furnace. A three‐dimensional multiphase CFD model using Eulerian approach has been developed to simulate the coal devolatilization and combustion process inside tuyere and raceway. The velocity field, temperature distribution, and combustion characteristics have been determined in details and the effect of tuyere diameter on the pulverized coal combustion process has been predicted. Numerical results show that the pulverized coal combustion process displays different characteristics when the tuyere diameter changes. For a bigger diameter tuyere, there is more coal devolatilization, and combustion occurs inside the tuyere, which results in a better combustion condition compared to smaller tuyere diameters. The gas temperature distributions inside the raceway are dependent on the tuyure diameter; the temperature for the large size tuyere is higher than that of the small one. The coal burnout changes from 85.3% to 60.0% when the tuyere diameter reduces from 0.165m to 0.146 m.     

A brief consideration about PCI of COREX melter-gasifier

By analyzing the thermal and burden structure conditions inside the melter-gasifier of COREX process,the advantage and disadvantage of PCI into the melter-gasifier are clarified.The influence of PCI on the running condition inside the furnace is analyzed based on the information from production operation and mathematical and physical simulations,and measures to tackle with the problems arising from PCI are proposed.The main results are as follows.①Due to the unfavorable conditions for coking of coal in t...     

两段式喷吹煤粉工艺的实践研究

两段式喷吹煤粉工艺具有保护炉内焦炭强度、降低高炉料柱压差的特点,有利于提高煤粉喷吹量、强化高炉冶炼,同时还可以降低高炉大喷煤对焦炭质量的苛刻要求。两段式喷吹煤粉工艺在某钢铁公司日产达到约3 200t的高炉实施,通过对风口焦炭、高炉尘及高炉操作指标的分析,考察了两段式喷吹煤粉工艺的应用效果。工业实践表明:该工艺能有效地保护焦炭强度,改善高炉炼铁的各项技术指标。     

高炉两段式喷吹煤粉工艺的生产实践

两段式喷吹煤粉工艺应用于瑞典SSAB Oxel(o)sund 2号高炉,效果显著.结果表明:若维持风口喷吹煤粉量不变,两段式喷吹煤粉工艺可以提高喷煤量,降低焦比,当第二段喷吹煤粉量5 kg/t时,焦比下降5 kg/t;改善高炉料柱透气性,降低料柱压差,使炉内煤气流分布更加合理,有助于高炉操作稳定,提高煤气利用率;第二段喷入的煤粉可以在高炉内被充分利用,并可以有效地抑制焦炭强度在高炉内的劣化,有助于降低在实施大喷煤工艺时对焦炭质量的苛刻要求;有助于减少炉墙热损失.     

喷吹煤粉对高炉下部压力场的影响

利用商业软件fluent研究了不同煤粉喷吹量和粒径下高炉下部压力场的变化。分析得出以下结论：在一定范围内,随着煤粉喷吹量增加,风口回旋区内绝对压力呈线性增加;大喷吹量会使高炉中心轴线、炉墙和死料柱截面上的压力增大;煤粉粒径由20～30μm增加到110～150μm,高炉中心轴线、炉墙和死料柱截面上的压力也会增大。     

Mathematical Model Development of Raceway Parameters and Their Effects on Corex Process

  Corex is an alternative ironmaking process and raceway is one of the important areas to maintain the stability of the furnace. The raceway parameters are well established for blast furnace operation. But for Corex process, it has not yet been established and optimized. Thus, a mathematical model was developed to determine various raceway parameters such as RAFT (raceway adiabatic flame temperature), tuyere gas velocity and kinetic energy. The model provides an idea about the raceway geometry, zone temperature and kinetic energy accumulated in tuyere gas. Besides, all the raceway parameters have been analyzed to find out their effects on the Corex process. It is found that RAFT influences the gasification reaction kinetics and higher RAFT generates more CO in reduction gas, which improves the metallisation degree of the DRI in shaft. It is also found that increased gas velocity and kinetic energy generate more fines and demand more coke to maintain char bed permeability. High coke rate increases the production cost and lowers the production of hot metal.