Laboratory spray dryerInfluence of operating parameters on the nature of the product

The influence of operating parameters on the nature of the product (the nature of the product referred to here, mainly the size and density) is as follows.

(1) the influence of feed rate: under constant atomization and drying operation conditions, the particle size and the bulk density of the dried products increase with the increase of feed rate.

(2) the effects of solid content in the feed solution: increase the solid content in the feed solution, the particle size of dry products also increased, in the constant drying temperature and feeding rate, due to the increase of solid content in the liquid, evaporation load will be reduced, thus get wet with low content of products, due to moisture evaporate quickly, easy to produce hollow particles dry and loose low density products.

(3) effects of feed temperature and reduce the viscosity: if need to transport and convenient liquid atomization, increasing feed temperature has a certain influence on the drying properties of products, increasing the feed temperature will reduce the total heat of evaporation of droplets required, but continue to improve the heat content of the liquid and the vaporization required the heat is very small compared to.

(4) the influence of surface tension: surface tension affects the properties of drying products by affecting drying and atomization mechanism. The proportion of fine droplets in the droplet increases, and the droplet distribution is wider. The material with low surface tension produces smaller droplets, while the larger the surface tension is, the larger the droplet size is.

(5) the influence of drying temperature of inlet air temperature on the import of dry air in the drying of products specially designed for expansion in drying droplets, increasing drying temperature will produce large loose particles, low density, however, if the temperature rises to the evaporation rate increases rapidly, so that the droplet expansion, crushing or splitting and then, will generate dense debris formed loose dust with large density.

(6) influence of droplet air contact speed: increase the contact speed between the droplets and air, will improve the mixing degree, so as to improve the heat transfer and mass transfer rate, with the increase of contact speed, evaporation time shortened, drying particle has an irregular shape, due to different products, bulk density change also, but not a general conclusion.