The difference between centrifugal pressure drying unit and pressure drying unit Centrifugal drying is mainly the centrifugal force generated by the centrifugal distribution plate (also called high-speed atomizer) that distributes the material into droplets, and is instantly dried after contact with the hot air through the volute hot air distributor. Centrifugal drying is due to the high-speed rotation of the material for centrifugal distribution, the diameter of the material indexing is relatively large, and a larger diameter is required. Therefore, the diameter of the centrifugal dryer is generally designed to be relatively large. At the same time, because the material is thrown out by centrifugal force, the relative size of the droplets is relatively uniform, the droplets are dried at the moment of contact with the hot air, the droplets are basically solid spheres, the particle size of the material is relatively uniform, but the relative resolubility is relatively poor, the particle size of the material is relatively small, and the general number of meshes is about 200 mesh when making collagen powder.
Pressure drying is the material is increased by a high-pressure pump, and the material is atomized at high pressure after passing through a wear-resistant nozzle, and the atomization angle is generally between 60-80°. The material and the hot air distributor flow in parallel for instant drying, the droplets are relatively concentrated during drying, and it is easy to produce hollow particles during high-intensity evaporation, and it is very easy for the material to be reconstituted. At the same time, the secondary agglomeration design can be carried out, the material from the cyclone separator can be agglomerated and regranulated, and the fine powder and fog droplets can be regranulated, and the particle size formed is relatively large, and the mesh number is generally about 120 mesh when making collagen powder. The traditional pressure spray drying is a big-bellied medium exhaust tower, and the new pressure spray drying tower has a narrow-body upper exhaust tower (the column section is relatively high, generally not less than 10 meters), and a wide-body upper exhaust tower (the column section is the smallest, generally 2.).44 meters) and tend to be the middle of the tower type, the middle body on the exhaust drying tower.
The difference between the air inlet mode: centrifugal spray drying can only be a parallel flow type of air inlet (that is, the material and hot air enter the tower body in parallel), and the pressure type spray drying can be both parallel flow type air inlet, countercurrent type air inlet, or mixed flow type air inlet. Generally, the production of collagen is a concurrent air intake.
The difference between exhaust methods: centrifugal spray drying is generally exhaust air at the bottom, and the heat energy utilization rate is low. Pressure spray drying can be used for both bottom and top exhaust, and the upper exhaust air on the top has a high relative heat energy utilization rate and is more energy-saving.
The difference in the later maintenance cost: the maintenance cost of the centrifugal distributor in the later stage of the centrifugal spray drying unit is relatively high. The post-maintenance cost of the pressure spray dryer is only to replace the spray sheet, and the maintenance cost is very low.
First of all, for collagen products, centrifugal drying and pressure drying are both applicable. However, the product reconstitution of the pressure spray dryer is good, the particle size is adjustable, and the upper exhaust tower has a high thermal energy utilization rate, which is more energy-saving. The height of the narrow-body upper exhaust tower is relatively high, and the wide-body upper exhaust tower is generally used for large output and multiple groups of nozzles. Since the current production capacity of collagen towers is relatively small, our company recommends that they tend to be wide and narrow.
Medium body pressure type upper exhaust spray drying tower between the body. When the water evaporation capacity is 250kg h, the inlet air temperature is 155 160, the exhaust air temperature is 90 95, the air inlet volume is about 10000m3 h, and the exhaust air volume is about 14000m3 h. The diameter of the tower body required for the use of pressure-type upper exhaust spray drying tower is about 45m, the length of the cylinder is about 549 meters, cone angle 55 °, if not equipped with fixed fluidized bed and vibrating fluidized bed, the total height of the tower is about 115m, the total height of the workshop is about 14m.
When the water evaporation capacity is 150kg h, the diameter of the tower body required for the use of pressure-type upper exhaust spray drying tower is about 38m, the length of the cylinder is about 488 meters, the cone angle is 55 °, if the fixed fluidized bed and vibrating fluidized bed are not prepared, the total height of the tower is about 10m, and the total height of the workshop is about 13m. The inlet air volume is about 6100m3 h, and the exhaust air volume is about 9000m3 h.