喷煤对COREX熔化气化炉炉况影响的物理模拟

通过COREX喷煤整体和区域模型整体和区域模型计算分析,研究了喷煤对块煤用量、理论燃烧温度、风口煤气量等重要参数的影响。计算结果表明：随着喷煤量的增加,风口煤气量增大,块煤用量和理论燃烧温度均降低。最后,本文建立了二维COREX熔化气化炉热态模型,利用石蜡模拟矿石,玉米粒子模拟焦炭。在热态物理模拟实验中,考察了矿/(块煤+焦)体积比、风温和风量等操作参数对COREX熔化气化炉炉况的影响。     

SiO_2还原对高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炉缸热状态的重要参数之一,而SiO2在风口前被碳还原对其产生的影响一直被忽略.通过实验研究了高炉风口前不同位置的试样,得到进入风口回旋区焦炭的温度和不同位置试样渣中SiO2的含量,从而确定出在风口回旋区SiO2的还原率,并建立了考虑SiO2还原情况下理论燃烧温度的计算公式,最后在富氧喷煤的条件下,分析和讨论了煤粉中灰分变化对理论燃烧温度的影响因素.     

高炉大量喷吹煤粉的探讨

本文从煤的燃烧性能和大量喷煤对高炉冶炼的影响,探讨高炉大量喷煤的可能性。在高炉风口燃烧带的高温下,煤粉不仅与氧燃烧,而且被二氧化碳气化。不必要求氧气过剩系数达到完全燃烧的要求。为维持风口前一定的理论燃烧温度,应采取提高风温并适当富氧。大量喷煤对高炉高温区热平衡、热流比等影响不大,不会影响高炉顺行。     

熔融气化炉风口回旋区冶炼特征的数值模拟研究

相比于高炉风口喷吹富氧热风,熔融气化炉风口采用常温纯氧,使得炉内质量、动量、热量的传输以及煤气流分布等冶炼特征与高炉存在较大差异.通过建立熔融气化炉风口回旋区二维数学模型,系统考察熔融气化炉风口回旋区内速度分布、温度分布及气体组分分布的冶炼特征.结果表明:在气固相热交换及焦炭 (或块煤形成的半焦) 燃烧反应的综合作用下,熔融气化炉风口回旋区内气体温度迅速升高至3 500 K以上;此外,风口前端存在小规模的气体循环流动现象,故风口前端扩孔破损现象严重,进而导致非计划休风率较高;为减少此类休风现象,可适当额外喷吹富氢燃料性气体 (天然气、焦炉煤气),不仅能降低风口回旋区内气体温度,更可替代部分固体燃料,并充分发挥其中H₂的高温还原优势,提升熔融气化炉冶炼效率.      

煤粉在Corex熔融气化炉内的燃烧行为研究

Corex熔融还原炼铁是新兴的炼铁工艺,虽然它可以不用或少用焦炭冶炼铁水,但是需要用块煤来生产.为了替代一部分块煤以及充分利用产生的煤粉,提出了往熔融气化炉喷吹煤粉的方法.Corex喷煤可以借鉴高炉喷煤的经验,但是它们之间有一些区别.采用热态模拟的方法对煤粉在Corex熔融气化炉内的燃烧行为进行研究,得到煤的粒度、挥发分含量以及喷吹位置和CO浓度等因素对煤粉燃烧率和气化率的影响规律.实验将为Corex喷煤技术的开发提供必要的理论支持.     

高炉喷煤发展与前景

煤粉燃烧与利用及喷煤后高炉顺行是提高喷煤量的主要环节。本文对煤粉粒度、风口均匀喷吹、富氧（包括氧煤喷枪）、风口前适宜理论燃烧温度、料柱透气性（煤气分布与炉料运动）、煤的质量、喷煤装备等进行了论述，并就喷煤极限和发展前景提出看法。     

COREX熔化气化炉区域模型及其理论燃烧温度

把熔化气化炉划分为炉缸区、风口区、填充床、流化床和自由空间5个区域。在已开发的COREX工艺整体静态模型的基础上,对各区域分别建立了物料平衡热平衡模型并联立求解。根据各区域内的物理化学进程设定各区域间边界的条件,模型计算可给出熔化气化炉内各区域的能量分布和物料流状况。利用区域模型还可计算喷煤对理论燃烧温度、炉缸渣铁温度、煤气量等的影响。     

高炉喷吹煤粉的适宜操作范围

为了降低高炉焦比,节约能源,通过首钢一高炉大量喷煤操作情况的分析,提出了高炉喷吹煤粉的适宜操作范围.无富氧喷煤量可达150kg,富氧时可达200kg以上.为提高喷煤效果,应注意维持适当的风口前理论燃烧温度和氧气过剩系数.大量喷煤后压差略有升高,但不影响高炉顺行.与炉腹喷吹还原气相比,风口大量喷煤是一种经济、有效的节焦方法.     

进一步扩大高炉喷煤量途径的研究

由于进一步扩大喷煤量受到风口前煤粉燃烧不完全的限制,作者设计了一套直接从生产高炉风口回旋区取出燃烧过程煤粉试样的取样装置。通过取样,研究了煤粉在风口回旋区的燃烧程度及变化规律。用模拟高炉风口回旋区条件的燃烧炉,系统地研究了对煤粉燃烧的影响因素,包括采用旋流的作用。还用煤岩相方法研究了煤粉结构在燃烧过程的变化。用传热传质及反应动力学理论分析并计算了煤粉的加热速度及燃烧反应速度,讨论了一些因素对它们的作用,从而提出了扩大高炉喷煤量,改善喷煤效果的措施和建议。     

高风温对喷煤率及效果的影响

天津铁厂1987年9月试喷煤粉,1988年元月份在2号高炉投入正常运行。煤粉比风口前焦炭温度低得多,1kg煤粉加热到1500℃需要吸收1884kJ热量,分解1kg煤粉又需吸收1009kJ热量,所以喷煤后理论燃烧温度下降。伴随喷煤量增加,这种现象愈为突出。这样不仅影响喷煤效果,甚至可     

A Modified Model for Calculating Theoretical Flame Temperature in Blast Furnace and Its Application

The theoretical flame temperature(TFT)before tuyere,always highly concerned by blast furnace(BF)operators,is one of the most important parameters for evaluating the thermal state of hearth.However,some influencing parameters,for example,the SiO2 reduction by carbon,were always neglected or inaccurate when calculating the TFT.According to the definition of TFT,the temperature of coke into raceway and the reduction rate of SiO2 in ash of coke and pulverized coal were obtained by analyzing the samples before tuyere in blast furnace.Taking full account of different factors,a modified model for calculating the TFT in blast furnace was established.The effects of the oxygen enrichment rate,the reduction rate of SiO2 in raceway,the ash content in coke and pulverized coal and the pulverized coal injection(PCI)rate on TFT were determined quantitatively.The modified model was applied to selecting the used coal for PCI in blast furnace.Considering the different SiO2 contents of mixed coal,the calculated TFT remained a stable level.This showed that the selected coal could be suitable for PCI in blast furnace.     

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...     

熔融气化炉内块煤裂解特性的差异化分析

为了研究块煤在熔融气化炉内高温结构演变和降解机制,采用扫描电镜和光学显微镜观察了COREX熔融气化炉风口焦和实验室自制半焦的形貌和显微结构,并结合不同试样的高温反应特性,确定了不同风口焦试样的来源。结果表明,风口焦中兴隆庄块煤形成试样含有较多的中粒和粗粒镶嵌结构,表面呈孔状结构;大同块煤形成试样中类丝炭较多,表面呈层状结构。根据结果提出应考虑灰分对煤焦高温强度的影响,在测量风口焦试样的反应性及反应后强度时应考虑灰分含量进行折算,并确定了以灰分的基准含量为13%进行折算为最佳条件。     

COREX炉内块煤裂化成焦的热态强度

通过对COREX所用2种块煤在不同条件下所成半焦的显微结构、热态强度进行观察,分析了影响块煤成焦质量的内在因素。比较2种块煤所成半焦的组成结构及性能差异后,发现兴隆庄煤成焦结构要优于大同煤,但兴隆庄原煤组织反应性较高,故在前期其煤成焦强度低于大同煤,直至成焦结构较多时,才高于大同煤。通过对COREX风口焦及实验室自制半焦的微观形貌和性能进行对比,确定了风口焦的来源,风口前兴隆庄煤形成焦炭的表面呈现出较浅的孔洞,其热态强度明显高于大同煤形成的焦炭。     

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...     

大同煤热解动力学研究

目前,COREX流程中的熔融气化炉采用块煤代替焦炭作为燃料冶炼铁水。块煤在熔融气化炉中的反应行为对炉况的稳定顺行及铁水质量有着重要的影响。采用非等温热重分析法针对COREX用煤（大同煤）在热解过程中的失重速率、失重量以及影响因子进行了研究,分析了煤热解的整个失重过程,并讨论了不同升温速率对热解的影响。同时,考虑煤热解过程的不同特性,采用分段尝试法建立了煤热解过程的动力学理论模型,进而得到相应的动力学参数,有助于更好地分析块煤在气化炉内的热解行为,为COREX流程块煤的合理使用及采用风口喷煤技术提供理论依据。     

COREX�������ԭ�򼰶Բ߷���

The tuyere-damaged phenomenon of COREX-3000 was investigated, and the conclusion was found that the combined effect of both melting loss under high temperature and scouring abrasion by high speed air flow led to the damage of tuyeres. The methods from five aspects were proposed to reduce the dilapidation of turyere through analyzing thermal distribution of COREX tuyere combustion zone. Based on that above, the measures that small coke was chosen as substitutes for part of Shanxi coke and oxygen-nitrogen blending injection replaced the oxygen injection were taken by Baosteel, which effectively prolonged the working life of tuyere.Besides, the effects of the measures above on COREX were analyzed in detail, and the following results show:Using Baosteel small coke improved the burden permeability to avoid that heat is gathered in tuyere combustion zone; Oxygen-nitrogen blending injection reduces heat production in tuyere combustion zone, lowers the heat conduction ability of air flow, and forms one thin carbon-nitride protective layer on tuyere surface to prolong the working life of tuyere.     

Characteristics and analyses of COG injection from tuyere in COREX melter gasifier

Coke oven gas (COG), as an environment-friendly source, is projected to be introduced into the COREX process to reduce solid fuel consumption. In this paper, a static model has been developed based on mass and heat balance, which can calculate characteristics of melter gasifier, such as the raceway adiabatic flame temperature (RAFT), volume and component of bosh gas. The results showed that compared with N2, the COG injection from tuyere is more effective on reducing the RAFT and improving the bosh gas volume. The quantity of COG injected is limited for the RAFT, and without other thermal compensation, the largest injection quantity is about 150 Nm³ t^?1. The quantity of COG injection can be increased by preheating tuyere oxygen, adjustment of fuel structure and addition of tuyere oxygen. COG injection can promote the reduction and hearth permeability, decrease the RAFT and protect the tuyere, which is beneficial to COREX operation.