【作者】 刘芳；

【导师】 郭健翔；

【作者基本信息】 青岛理工大学 ， 供热、供燃气、通风与空调工程， 2010， 硕士

【摘要】 高炉渣是钢铁产业最主要的副产品,它含有丰富的热量,其温度高达1450℃,按照将其冷却到室温计算,一吨高炉渣可放出(1.26~1.88)×106kJ的热量,如何能把这部分热量加以回收利用,将是重大的节能环保的研究课题。目前国内外钢铁行业基本上都是采用水冲渣工艺,用水作为冷却媒介,通过水的蒸发将热量带走来冷却高温炉渣,然后将其作为水泥原料出售。水渣处理工艺存在的主要问题:大量的新水消耗;熔渣余热没有回收;系统维护工作量大;冲渣产生的气态硫化物带来空气污染;粉磨时,水渣必须烘干,仍要消耗能源。干法高炉渣余热回收技术与水淬工艺相比优点是显而易见的:水资源消耗少;污染物排放少;可回收其高品位的热量;省去了庞大的冲渣水循环系统,取而代之的是节能环保的高炉渣干法余热回收发电系统。它虽远未达到工业应用的程度,但符合钢铁业节能环保的发展趋势,尤其对国内水资源和能源短缺的状况来说具有重要的现实意义。针对目前这种状况,本文提出一种用于高效回收高炉渣余热的新型的流化床技术,研究内容包括:(1)提出一种新型的流化床结构并对其进行初步的设计计算,使其更有利于增强空气与高温炉渣之间的换热;(2)应用CFD数值模拟研究这种结构下的流化床内部的气固两相流的流动及传热现象,通过改变出渣口大小、物料循环量和流化风速这三个控制参数,探索它们与炉渣体积分数、流化高度、换热系数等参数之间的关系以及它们对空气出口温度、取热量和热回收效率的影响;(3)制作了样机,为高炉渣余热回收实验研究做好了准备。计算结果表明,出渣口开度0.005m~0.015m时,进渣流量3.3912ton/h~10.1736ton/h ,进风流量6.12m3/h~8.16m3/h ,即进渣速度0.1m/s~0.3m/s,进风速度3m/s~4m/s时,余热回收效率能达到60%以上。更多还原

【Abstract】 Blast furnace slag is the main by-product during the process of steel production. It contains rich resources of high-grade sensible heat. As blast furnace slag is discharged at the temperature of about 1450℃, there is (1.26~1.88)×106kJ/ton sensible heat can be recovered if it is cooled to room temperature. It is obvious that the recovery of the sensible heat can save a lot of energy. How to recover the sensible heat will be a major research topic of energy reserving.Nowadays most of the steel enterprises at home adopt water quenching process to treat blast furnace slag, and then use the treated slag as aggregate for concrete making. There are many shortcomings during the course of processing. Firstly, the sensible heat have not been recovered, secondly, the water quenching process discharges harmful gases into the air ,such as hydrogen sulfide, sulfur dioxide and others which finally cause environment pollution, thirdly, the water quenching process would be a waste of a large amount of new water.Compared to water quenching process, the advantages of dry slag waste heat recovery technology is obvious. First, less consumption of water resources, second, less emissions of air-pollution gas, third, high-grade heat can be recovered, fourth, a huge water quenching system can be omitted and replacing it with an economical dry slag waste heat recovery system.Although it is far from industrial applications, it meets the steel industry development trend of energy-saving and environmental protection. It is of important significance for domestic water and energy shortage station.In response to the status quo, a high recovery efficiency technique which is based on the fluidized bed for blast furnace slag waste heat recovery is put forward in this paper.Main contents discussed in this paper are as follows: Firstly, a novel type of fluidized bed structure used for heat transfer process in the technology of blast furnace slag waste heat recovery is proposed. It is designed to use minimal amount of air flow state so as to raise the air temperature at the exit.Secondly, dense gas-solid two phases flow mechanism based on the fluidized bed is discussed. This paper focuses on the mechanism of momentum transfer and heat transfer between air and high-concentration granulated slag particles by means of CFD numerical simulation (using Eulerian multiphase model). By changing the three control parameters of the slag exit size, slag flow rate and air flow velocity, we aim at exploring the control parameters’ relationship with the slag volume fraction, fluid height, heat transfer coefficient, and their impact on the air outlet temperature, heat recovery amount and heat recovery efficiency.Thirdly, a prototype was produced for the experimental study of blast furnace slag waste heat recovery.The results show that when the width of slag outlet between 0.005m and 0.015m, the slag flow amount between 3.3912ton/h and 10.1736ton/h, air flow amount between 6.12m3/h and 8.16m3/h. That is, the slag velocity between 0.1m/s and 0.3m/s, and the air velocity between 3m/s and 4m/s, the heat recovery efficiency can be above 60%.更多还原