Calcination of Fine Limestone Particles by a New Type of Fluidized Bed Developed for a Fine Particle Treatment

点击翻译按钮获取中文摘要

Calcination of fine limestone particles with 1-30 mum in diam.was carried out continuously by feeding the fine particles into the fluidized bed of medium particles with 500-1500 mum in diam.in the temperature range between 800-1000 C.Calcined limestone particles which were entrained from the bed were collected with a cyclone and a bag filter. Effects of bed temperature, particle size of the limestone, mean residence time of the gas in the bed, the major factors for the calcination conversion in this calcination system, on the calcination conversion were examined in the experiment. And the calcined particles were also studied from the view points of specific surface area and pore size distribution.From the experiments, relationships between each factor and calcination conversion were clarified. The suitable temperature range for the calcination was between 850 and 950 Cin this system, and as large as 97% conversion wes obtained at a certain condition. It was analytically found that this process provide a high calcination conversion with lower temperature and much shorter residence time of the particle compared to that of a conventional process. The calcined particles by this process had larger specific surface area of 15-60 m^2/g which is much larger than that of the paricles given by the conventional way. It is expected that the calcined fine powder with such a large surface area can be used as SO_2 solvent in a desulfurization process.