多管炉工作状况下的温度分布

本文以钨、钼粉末制备常用十五管还原炉为对象,采用特制的加长型热电偶,分别对每根炉管和各炉管的10个截面在通氢状况下的温度进行测定,比较两种炉子的截面温差和沿炉管方向温度分布。结果表明:天然气炉的截面温差最大达到134℃,而电炉最大为65℃;沿炉管方向的温度分布曲线电炉也更加平滑,即电炉的温度分布更均匀一致。从炉子传热过程和结构方式入手初步探讨了影响炉子温度分布和均匀性的原因,天然气炉因对流传热受到气体流速、压力和操作等多因素的影响而难以控制炉子的温度分布,电炉则相对简单和稳定。比较了两种设备生产细颗粒钨粉的粒度分布,结果表明天然气炉的钨粉粗颗粒含量高,粉末不均匀,在细颗粒生产上电炉质量更优。

Temperature Distribution of Multi-tube Furnace under Working Conditions

Taking fifteen-tube reducing furnace used for producing tungsten and molybdenum powder as the object, the temperatures of each furnace tube and ten cross sections in case of hydrogen blowing in were measured by using a special lengthening thermocouple.The temperature difference of two types of furnace and the temperature distribution along the direction of the tube were compared.The results show that for the natural gas furnace,the maximum value of temperature difference for the same cross-section is 134℃,but it is only 65℃for the electric furnace and the temperature distribution curve along the tube is more smoother,so the electric furnace has relatively homogeneous temperature. The factors causing temperature difference were discussed from the two aspects including heat transfer and the furnace conformation.The heating of natural gas furnace depends on convective heat transfer,which influenced by the gas flow rate,pressure,operating procedure and so on,so it is more difficult to control the temperature,but the electric furnace has simpler structure and uniform temperature.The particle size distribution of fine tungsten powder prepared by the two types of furnace was compared.The results show that more content of coarse grain existed in the tungsten powder from natural gas furnace and the particle size is non-homogeneous,so the electric furnace has advantage in the production of fine tungsten powder.