Characteristics of materials used in double cone rotary vacuum dryer

- Jan 30, 2020-

1) Viscosity of the material. The viscosity of the material changes with its moisture content. The viscosity can make the material agglomerate and stick to the wall of the cylinder. After drying, it is easy to stick to the dust remover and the pipe wall. Pneumatic vibration and crushing device can be used.

2) The permissible temperature of the material. The allowable temperature is the high temperature that the material can bear. If the temperature is exceeded, the potency of the material will be changed, the decomposition will be destroyed or the color will change.

3) The bulk density of material the mass of material per unit volume is called bulk density. Because the material is a mixture of the absolute dry material and the moisture content, the absolute dry material is usually granular, powdery or solid block material, and the gap between the particles of the absolute dry material is also different with the different moisture content in the material. There is a great difference between the bulk density of the raw wet material and that of the material in the drying process.

4) When the slip angle of materials is increased to a certain angle, the side materials will slide down. The angle between the inclined surface and the bottom surface where the material slips is called the slip angle of the material. The slip angle is related to material composition, moisture content, particle size and viscosity. When selecting the double cone dryer, you can refer to the slip angle of the material and select the angle of the cone.

Drying temperature of selected materials in double cone rotary vacuum dryer

The proper temperature can be selected according to the material properties. Generally, the variable temperature drying method can be used. In the early stage of drying, the temperature is low, and gradually increases to increase the drying rate.

When vacuumizing and heating is started, the drying speed is slow. When the material is heated above the vaporization temperature of water, the drying speed will suddenly speed up. The material is heated to the vaporization temperature under the corresponding pressure within the allowable temperature range and vaporized in large quantities. At this time, the material temperature remains the same. The added heat is used as the vaporization heat and various heat losses. The vacuum system continuously discharges the vaporized steam and keeps it The pressure difference between the evaporation surface and the space makes the drying continue. The moisture content of the material decreases to a certain extent, and the water evaporated from the material decreases. Under the condition of constant heating capacity, the temperature of the material begins to rise, the pressure difference between the evaporation surface and the space decreases, and the drying process turns to the deceleration stage. The drying rate gradually decreased to zero.