A novel model for cost performance evaluation of pulverized coal injected into blast furnace based on effective calorific value

The combustion process of pulverized coal injected into blast furnace involves a lot of physical and chemical reactions. Based on the combustion behaviors of pulverized coal, the conception of coal effective calorific value representing the actual thermal energy provided for blast furnace was proposed. A cost performance evaluation model of coal injection was built up for the optimal selection of various kinds of coal based on effective calorific value. The model contains two indicators: coal effective calorific value which has eight sub-indicators and coal injection cost which includes four sub-indicators. In addition, the calculation principle and application of cost performance evaluation model in a Chinese large-scale iron and steel company were comprehensively introduced. The evaluation results finally confirm that this novel model is of great significance to the optimal selection of blast furnace pulverized coal.

3D model study of coal/coke combustion in a blast furnace effects of coal properties

A three-dimensional mathematical model of the combustion of pulverized coal and coke has been developed.The model is applied to the blowpipe-tuyere-raceway-coke bed region in an ironmaking blast furnace in one computational domain,which includes two parts:pulverized coal combustion model in the blowpipe-tuyere-raceway cavity and the coal/coke combustion model in the surrounding coke bed.The effects of coal properties are examined comprehensively,in terms of coal burnout and gas species distributions.The results indicate that using a coal of fine particle size or high VM content could improve burnout and would affect the gas composition considerably.The burnout is examined in two ways:compared with burnout along tuyere axis,burnout over the raceway surface is a more sensitive and sensible parameter to describe the amount of unburnt char entering the coke bed.The model is useful for examining the flow-thermo-chemical characteristics of the pulverized coal injection (PCI) process under various conditions in a blast furnace.

Thermal analysis and kinetic modeling of pulverized coal combustion accompanied with coke breeze

Pulverized coal injection technique has been widely used as a means of reducing coke consumption during ironmaking process.Owing to the increasing shortage of fossil fuels,other substitutes such as biomass,plastic,and waste tires have been studied in recent years.Coke breeze as one of the by-products of coking industries has been investigated as a substitute for partial pulverized coals.The combustion characteristics of blended fuels were estimated based on the flammability index C and the combustion characteristic index S.For different coke breeze additions,the combustion was divided into two stages,and the apparent kinetic parameters of the two stages were estimated by fitting the experimental data to the shrinkage reaction model and shrinkage diffusion model,respectively.Results showed that with the increase in coke breeze addition from 15% to 60%,the indexes C and S decrease,and the activation energy of the first stage remains almost constant,while that of the last stage increases from 16.89 up to 67.18 kJ mol^(-1),which indicates that adding coke breeze decreases the combustion efficiency of pulverized coal.Comparing the combustion and kinetic parameters under different coke breeze addition conditions,the optimal addition amount is suggested to be within 15%.

炉内喷钙脱硫的模拟

煤粉炉内喷钙脱硫是应用较为广泛的脱硫技术，运用逾渗理论建立氧化钙脱硫模型，用来模拟煤粉炉喷钙脱硫过程，并对脱硫影响因素：ＳＯ２ 浓度、温度、Ｃａ／Ｓ比等进行了研究，模拟计算显示了这些因素对脱硫效果的影响，其结果与试验数据相一致．通过该模型计算可以优化脱硫过程。

当前高炉喷煤存在的问题及解决途径

通过对当前高炉喷煤普遍存在的诸如基本无综合原煤场、制粉系统基本没有建立相关数据库和优化模型,以及高炉操作者在对喷煤量等的调整上尚存一定的盲目性等问题进行了详细分析,并提出了相应的解决办法。

炉内状态随煤比的变化

运用由质量、热量平衡方程和质量、热量传输方程构成的高炉传输模型，计算分析了高炉内状态参数随煤比的变化规律．计算结果表明，在煤比为１６０～１７０ｋｇ／ｔ－Ｆｅ时，间接还原度出现极大值，是煤粉喷吹的最佳阶段．

高炉喷煤直吹管内气粉两相流的浓度场

在对高炉局部富氧喷煤直吹管内气固两相流流场研究的基础上 ,对直吹管内氧和煤粉的浓度场进行了数值研究 ,包括氧 -煤喷枪的插入角度和枪位、局部富氧射流的漩流数以及煤粉粒度的影响。结果表明 ,氧 -煤喷枪的插入角度和枪位对氧 ,特别是对煤粉的浓度场分布有较大的影响 ;合适的富氧率下氧气的旋流作用能够促进氧气与煤粉的混合 ,增强氧 -煤喷枪出口附近区域的动量传输和质量传输 ;利用氧 -煤喷枪可以形成一个局部富氧区域 ,显著提高煤粉周围的氧浓度 。

高炉喷煤直吹管内气粉两相流的流场

在高炉富氧喷煤过程中 ,直吹管使喷入的煤粉与氧气预混、预热 ,并促使煤粉的热解和部分煤的燃烧。运用多相流的拟流体模型建立了高炉局部富氧喷煤直吹管内气粉两相流动的数学模型 ,对气粉两相流场进行了数值研究 ,探讨了气相和煤粉的速度分布规律及其影响因素 ,其中包括氧 -煤喷枪的结构、漩流数和富氧率等。结果表明 ,氧 -煤喷枪的漩流、富氧率等仅在氧枪出口的有限区域内对流场有较大的影响 ;喷煤对整个直吹管内的流场影响较小 ,但在氧 -煤喷枪出口附近区域会促使气相和煤粉激烈混合 。

高炉富氧喷煤经济评价模型

在高炉多区域热质平衡数学模型基础之上建立了高炉富氧喷吹煤粉经济评价模型,并利用模型计算了高炉富氧喷煤之后高炉相关操作参数和吨铁冶炼成本的变化.结果表明,增加富氧率提高喷煤比可以有效降低吨铁冶炼成本,降低成本的幅度主要取决于煤粉和焦炭之间价格差别（煤焦差价）和氧气单价,煤焦差价越高、氧气单价越低,吨铁成本降低幅度越大,对应的最佳富氧率水平越高,在目前的原燃料成本条件下,降低成本的最佳富氧率可以达到15％～18％.此外,该模型还可够应用于不同高炉流程冶炼生铁的经济效益评价,为探索低成本炼铁方法提供支持.

串联罐式喷煤系统称重传感器的补偿研究

以唐钢炼铁厂三号(2560m3 )高炉喷煤系统为研究对象。针对喷煤系统在中罐及软连接充压过程中,中、下罐电子秤显示不准的问题进行了研究,并根据喷煤系统设备的实际状况,提出了一种新的解决方案,即以建立喷煤量控制的数学模型为基础,计算喷煤过程中喷煤量的补偿量,并返算出喷煤过程中中、下罐煤粉的瞬时重量,作为电子秤的显示值,从而解决了由于充压导致的中罐“上浮”的问题。