工业催化剂及其载体焙烧设备进展

焙烧几乎是所有固体催化剂及其载体制备的最后环节。焙烧温度对催化剂的结构性质、物相、晶粒大小、表面酸性以及强度、比表面、孔分布等性质具有重要影响,并最终影响催化剂的综合性能。从实验室少量焙烧到大批量的工业生产,即从小容积、温度场均匀、浓度场均匀和间歇操作的实验室焙烧装置放大到温度场和浓度场尚不十分清晰的工业焙烧设备,有必要研究设备变化的工业放大效应。在催化剂工业生产中,有微波焙烧炉、厢式焙烧炉、回转式焙烧炉、网带式焙烧炉、流态化焙烧炉、立式焙烧炉、隧道窑、梭式窑、辊道窑等多种焙烧窑炉可供选择。厢式炉不适于连续生产,网带式炉不适于高温焙烧,对于大批量催化剂的高温焙烧往往采用隧道窑和连续式回转炉。通过炉体自身的旋转,回转炉能促使物料颗粒之间的相互混合,而隧道窑则不能;回转炉炉体不漏风,物料床层截面主体温度均匀,而隧道窑中易出现窑车下部漏风、窑车自身蓄热等问题,从而引起预热段断面的上下温差;此外,隧道窑温度分布不均匀。微波炉具有加热速度快等优点,是近年来发展较快的焙烧方式。

Advances in Industrial Catalyst and Catalyst Carrier Roasting Equipment

Roasting is the last process for the preparation of almost all solid catalysts and their carriers.Roasting temperature has a significant influence on the structural properties,phase ,grain size ,surface acidity and other properties of catalyst such as intensity, specific surface area and pore distribution and eventually affects the overall performance of catalyst.In order to transition to large-scale industrial production from small-scale laboratory roasting ,namely scaling up from laboratory roasting units featuring small capacities ,even temperature fields and concentration fields and intermittent operation to industrial roasting equipment whose temperature and concentration fields are not very clear,a study on industrial amplification effect of equipment changes is necessary.In industrial catalyst production,muhiple roasting furnace options are available,including microwave roasting furnaces,compartment-type roasting furnaces,rotary roasting furnaces,mesh-belt roasting furnaces,fluidized roasting furnaces,vertical roasting furnaces,tunnel furnaces,shuttle kilns and roller kilns.Compartment- type roasting furnaces are not suitable for continuous production.Mesh-belt roasting furnaces are not suitable for high-temperature roasting.Tunnel furnaces and continuous rotary furnaces are usually used for high-temperature roasting of large quantities of catalyst.Through rotation,a rotary furnace can mix material particles ,while a tunnel furnace is unable to do so.The body of a rotary furnace is air-tight and the temperature on the most of the material bed section is even.In contrast,a tunnel furnace often has an air leak at the lower section of the kiln vehicle and heat often accumulates on the kiln vehicle itself.These will result in a temperature difference between the areas above and below the section of the preheating zone.In addition,temperature distribution in a tunnel furnace is uneven.In recent years,the application of microwave roasting furnaces has been increasing rapidly owing to their advantages such as fas