Factors affecting the lyophilization time of four-ring lyophilization experimental lyophilizer

Four-ring freeze-drying experimental freeze dryer is more common in daily life, vacuum freeze-drying technology, referred to as freeze-drying, also known as sublimation air drying
.
Lyophilization is a specific method
of pre-freezing aqueous materials and then sublimating them in a vacuum state to obtain air-dried objects.
The freeze-dried object, the original biological and chemical characteristics are basically unchanged, easy to store for a long time, after soaking in water, it can return to the form before lyophilization, and can maintain its original biochemical properties
.
Four-ring lyophilization experimental freeze dryer is mainly a kind of lyophilization equipment that uses vacuum lyophilization technology to freeze-dry items, because the lyophilization time required by different products is different, in addition, are there other factors that can affect the lyophilization time of the lyophilizer? The first is the form and composition of the material to be processed by the lyophilizer: according to the form of the lyophilized material, it can usually be divided into solid and liquid
.
The influence of the form of the solid and the concentration of the liquid on the rate of freeze drying is very large
.
Then there is the pre-freezing rate of the lyophilizer: the size of the crystals formed during freezing can greatly affect the drying rate and the dissolution rate
of the dried product.
The quick-freezing and slow-freezing processes have the following differences: quick-freezing produces smaller ice crystals, and slow freezing produces larger
ice crystals.
Large ice crystals are more conducive to sublimation, while small ice crystals are not conducive to sublimation, and rapid freezing will lead to a decrease in the rate of sublimation and a fast desorption rate; Slow freezing results in a fast sublimation rate and a slow
resolution rate.
There is also the problem of loading: when the material is lyophilized, there is a certain ratio of surface area to the thickness of the substance after being divided into containers, that is, lyophilization is related to
the loading.
The small surface area and thickness are conducive to water sublimation, easy lyophilization and ideal
quality.
When drying, the amount of wet weight to be dried on the area tray is an important factor in determining the drying time, in general, the thinner the thickness of the material accumulation, the faster the heat and mass transfer speed, and the shorter
the vacuum freeze drying time.
However, if the material thickness is thin, there are fewer materials dried per batch on the lyophilization area, which is not conducive
to improving the lyophilization area and time yield.