Vacuum freeze drying machine: energy saving measures from the lyophilization process
1.
To adjust the shape of the material handling and concentration
for solid materials, if not the shape of the high requirements, by cutting processing to increase the heat and mass transfer area, so as to speed up the freeze-drying process, reduce the freeze-drying time;
If the shape of the material requirement is high, the cutting is not allowed to take the piercing process, to facilitate material internal water vapor escape, through enhancing mass transfer process to improve the rate of freeze-dried.
for liquid ingredients, if contains more colloid material, when the concentration is higher, appropriate to reduce the concentration of the material will help to improve the rate of freeze-dried.
But, the material concentration also shoulds not be too low, otherwise will increase the energy consumption for removing water too much, and easy to cause the water vapor diffusion channel congestion, reduce the freezing rate.
If the liquid raw material moisture content is very high, such as water content as high as 80% above, freeze-dried should as far as possible before its enrichment, in order to improve the drying rate.
2.
Vacuum freeze drying system
for vacuum freeze drying system, the vacuum degree should be maintain, refrigeration system and drying system three aspects of energy saving measures.
First of all, the low vacuum is good for heat spread outward, but at the same time, water vapor spread outward resistance will increase;
High vacuum degree result instead.
The higher vacuum degree, energy consumption is necessary to sustain the vacuum.
Therefore, choosing the appropriate vacuum degree for consumption.
Second, improve reduce condensation temperature, evaporation temperature, the scientific and reasonable way of heat transfer, adopts the automatic system and realize comprehensive utilization of energy are conducive to the lyophilization process to reduce energy consumption.
3.
Improve the heating mode and heating temperature
heating temperature control including the temperature control of the frozen layer and layer has dried.
In the case of maintain melt materials, freezing temperature and the higher the temperature, the better.
Without material degeneration or has dried layer under the premise of structure collapse, try to use higher has dried layer temperature, to shorten the drying time.
4.
Control speed and load raw precool
wang jie, etc. In the vacuum freeze-drying process when found, precool speed affect the formation of ice crystals, faster rate of freezing ice crystals is small, does not favor the sublimation, drying time is long, but after working dissolve quickly.
Slower rate of freezing ice crystals is bigger, good for dry and dehydration, but after working dissolved slowly.
In addition, per unit area on the tray, the thickness of the material accumulation is more thin, the faster the heat transfer and mass transfer, the shorter the drying time.
However, freeze-dried material thickness thin, unit area less per batch drying of material, to improve the yield per unit freeze-dried area and per unit time.
So, choose the appropriate materials plate loading capacity and cooling rate can reduce the energy consumption.
