炭素焙烧炉热工过程数值模拟及优化研究

发布时间：2018-03-27 13:16

  本文选题：炭素电极　切入点：焙烧炉　出处：《湘潭大学》2015年硕士论文

【摘要】：我国炭素电极生产属于高能耗产业,炭素焙烧是其生产过程中重要热处理工序之一,对其进行结构及运行操作参数优化,实现节能降耗潜力巨大。鉴于炭素焙烧热工过程的复杂性,利用数值模拟方法对炭素焙烧炉的热工过程进行系统研究,改善焙烧炉运行条件具有重要意义。针对上述中炭素电极块温度分布不均、焙烧周期长等问题,研究了炭素焙烧炉结构和操作参数对其热工过程的影响。主要工作和结论如下:1)以某炭素厂12室倒焰式炭素焙烧炉为研究对象,首先对其开展燃烧试验和热平衡分析,发现焙烧炉内热损主要是排烟损失,超过了69%,这导致焙烧炉热效率低下,延长了焙烧周期。通过对实际物理模型进行合理的简化和假设,建立了炭素焙烧炉热工过程的数学模型。基于FLUENT软件,根据炭素焙烧炉焙烧工艺的特点,建立了炭素焙烧炉热工过程仿真系统。2)数值模拟研究了初始工况下焙烧炉内速度场、温度场、浓度场和炭素电极块升温曲线及最终焙烧温度分布规律。模拟结果表明:炉内的高温烟气流主要向着下降火道出口处负压方向流动,对炉内其他区域带动作用较少;在一个焙烧周期内,造成炭素电极块实际焙烧升温速率始终滞后于目标升温速率,低于目标焙烧温度约200℃;同时炭素电极块在竖直方向上温度分布不均匀,沿高度递增方向,炭素电极块内温度逐渐升高,最大温差值超过200℃。3)通过在炭素电极块下方采用添加一条支火道补偿加热的方法,减小炭素电极块在竖直方向的温差,模拟结果表明:炭素电极块达到相同焙烧平均温度时,改进后的炭素电极块的焙烧升温时间更短,节省了15.35小时,相当于节省约655kg标准煤;同时炭素电极块上下温差明显缩小,最大温差小于70℃。4)在火道结构优化的基础上,进一步分析了助燃空气温度、火道出口负压值等因素对炭素电极块升温及温度均匀性的影响。随着助燃空气温度的增加,炭素电极块的焙烧温度得到提升,且其内部的温差有所降低,均匀性更好。负压为3Pa左右时,火道内烟气平均温度较高,炭素电极块内温度较为均匀。
[Abstract]:Carbon electrode production in China belongs to high energy consumption industry. Carbon roasting is one of the important heat treatment processes in the production process. The structure and operation parameters of carbon electrode are optimized. In view of the complexity of the thermal process of carbon roasting, the thermal process of carbon roaster is studied systematically by numerical simulation. It is of great significance to improve the operation conditions of roasting furnace. In view of the above problems, such as uneven temperature distribution of carbon electrode block and long roasting period, etc. The influence of the structure and operation parameters of carbon roaster on its thermal process was studied. The main work and conclusions are as follows: 1) taking the 12 chamber reverse flame type carbon roaster in a carbon plant as the research object, the combustion test and thermal equilibrium analysis were carried out. It is found that the heat loss in the roasting furnace is mainly smoke exhaust loss, which exceeds 69, which leads to the low thermal efficiency of the calciner and prolongs the roasting period. The actual physical model is reasonably simplified and hypothesized. The mathematical model of the thermal process of carbon roaster was established. Based on FLUENT software and according to the characteristics of calcination process of carbon roaster, the simulation system of thermal process of carbon roaster was established. The velocity field in the calciner under the initial working condition was studied by numerical simulation. The temperature field, concentration field, heating curve of carbon electrode block and the distribution law of final calcination temperature. The simulation results show that the flow of high temperature smoke in the furnace is mainly towards the negative pressure direction at the outlet of the falling fire channel, and it has little driving effect on other regions of the furnace. During a roasting period, the actual heating rate of the carbon electrode block always lags behind the target heating rate, which is about 200 鈩，

本文编号：1671669