转底炉金属化球团滚筒冷却机传热模型研究

Research on heat transfer model of drum cooler for metallized pellets in rotary hearth furnace

针对目前冶金行业转底炉工艺中圆筒冷却机无法回收球团显热的问题,本文提出采用在循环流化床锅炉中广泛应用的滚筒冷却机来冷却球团的新方案,并据此建立滚筒冷却机的传热模型,通过计算得到球团终温与冷却水出口温度及冷却机的表观传热系数。结果表明:球团的终温随滚筒转速的升高而降低,随球团流量和冷却水入口温度的升高而升高;冷却水出口温度随金属化球团流量和冷却水入口温度的增大而增大;冷却机的表观传热系数随滚筒转速、球团流量和冷却水入口温度的增大而增大,随冷却水流量的增大而减小。本文引入滚筒冷却机将球团的温度从1100℃降低至70℃,同时避免球团内部的氧化问题,符合高温球团的冷却要求,证明了将滚筒冷却机用于转底炉工艺的可行性。

In view of the problem that the cylinder cooler cannot recover the sensible heat of pellets in the rotary hearth furnace process in the metallurgical industry,a new scheme of using the drum cooler widely used in circulating fluidized bed boilers to cool the pellets is proposed,the heat transfer model of the drum cooler is established accordingly,and the final temperature of the pellets and cooling water as well as the apparent heat transfer coefficient of the cooler by calculating are obtained.The results show that,the final temperature of the pellets decreases with the increase of drum speed,and increases with the increase of pellet flow and cooling water inlet temperature;the outlet temperature of the cooling water increases with the increase of the metallized pellet flow rate and the cooling water inlet temperature;the apparent heat transfer coefficient of the cooler increases with the increase of drum speed,pellet flow rate and cooling water inlet temperature,and decreases with the increase of cooling water flow rate.The drum cooler is introduced to reduce the temperature of the pellets from 1100℃ to 70℃,and at the same time,the oxidation problem inside the pellets is avoided,which meets the cooling requirements of high-temperature pellets and proves the feasibility of using drum cooler in rotary hearth furnace process.