China's energy consumption accounted for the total energy consumption of drying of GDP 12%, the use of domestic drying technology energy rate of only 40% to 50%, while the foreign is as high as 70%. Today in the energy shortage, drying industry is very energy saving potential of the industry, how to take effective measures to reduce the drying of industrial energy consumption, drying equipment research and development of high efficiency and energy saving is the whole drying industry direction. Drying as an important link in the process, widely used in various industries, and expanding the scope of. Double cone rotary vacuum dryer vacuum drying, cylinder pressure is always lower than the atmospheric pressure, molecule number is less, low density, low oxygen, so it can dry easily oxidized drugs, less material contamination opportunity.
Because the vacuum drying, the material between the internal and external temperature gradient is small, due to osmosis the solvent alone could move and collection, overcome the phenomenon of hot air drying solvent separated born. Because the water in the vaporization process temperature and steam pressure is proportional to, so the vacuum dry, the water in the material can reach at low temperature gasification, low temperature drying, especially a heat sensitive materials production. Because the water in the vaporization process temperature and steam pressure is proportional to, so the vacuum dry, the water in the material can reach at low temperature gasification, low temperature drying, especially a heat sensitive materials production. Double cone rotary vacuum dryer, vacuum drying can eliminate surface hardening phenomenon caused by the atmospheric pressure hot air drying, vacuum drying because of materials between inner and surface pressure, effect of pressure gradient in water quickly move to the surface, no surface hardening.
Double cone rotary vacuum drying process can be divided into the first heating, constant temperature, the first second heating, constant temperature, cooling the five stage second.
The first heating is heating the material, the heating of the preheating stage. This stage, the moisture evaporation rarely.
The first is a constant temperature constant drying rate stage, in this stage, the material of free water, surface water and capillary water a lot of vaporization. Therefore, the temperature and the vacuum state is constant, and the vacuum degree and the drying temperature water saturated steam pressure approximately.
Second heating is heating material transfer internal moisture to the surface of materials, due to the vaporization of the material caused by little moisture, temperature and vacuum degree increases.
Second constant temperature is vaporized material wrapped water and water of crystallization stage, due to moisture migration rate and vaporization rate are similar, so the temperature and vacuum degree of a steady state.
The cooling phase begins, close the steam heating, the cooling water to the barrel body cooling jacket, simplified the internal material temperature decreases, so that the discharging drying products. |
