Treatment method of organic solvent spray dryer sticky wall

2 The influence of equipment parameters on the viscosity of traditional Chinese medicine organic solvent spray dryer Spray drying is a better method for fluidized drying technology for liquid materials, the process is to use the atomizer to spray the concentration of liquid materials into mist-like droplets, heat exchange in the drying medium to make the solvent in the mist-like droplets evaporate rapidly, and obtain powdery and granular products
.

Due to the different physical and chemical properties of traditional Chinese medicine ingredients, the rate of mass transfer and heat transfer is also quite different, resulting in different degrees of viscosity phenomenon
.

Under the premise of fully grasping the physical and chemical properties of Chinese herbal extracts, the condition of the adhesive wall can be improved by adjusting the parameters of
the spray drying equipment.

2.
1 Organic solvent spray dryer nozzle installation In the spray drying process, increase the dispersion of the material, which can accelerate the heat transfer and mass transfer process
.

The installation of the nozzle is important
for the spray equipment.

When the group of droplets leaves the nozzle, its shape is a tapered membrane filled with compressed air, and the droplets should be evenly distributed in the spray cone; The spray cone is symmetrical, if the center is not the center, it will deviate from the center line, which will affect the atomization effect, resulting in an increase in the diameter of the droplets, and in severe cases, the liquid line will appear, resulting in the phenomenon of
sticky walls.

Therefore, concentricity
in the process of use.

2.
2 Hot air volume The quality of air volume control is finally reflected in the moisture content of the dry material, which is directly related to
the sticky wall.

Since the spray drying process operates at a slight negative pressure, whether the droplets can achieve a drying effect and remove the dried material depends on the amount of
hot air.

At the same time, the diameter of the droplet can be adjusted
by the amount of hot air.

With the increase of hot air volume, the diameter of the droplets decreases, the drying is accelerated, and the possibility of sticking to the wall is relatively reduced
.

However, the air flow is too large, the moisture absorption of the resulting powder is enhanced, and the sticky wall phenomenon will occur during the spraying process; The air flow is too small, resulting in a large fog diameter, insufficient drying, and a sticky wall phenomenon
.

2.
3 Organic solvent spray dryer inlet air temperature The level of inlet air temperature is also the main factor
affecting the viscosity.

Studies have shown that if the air heater is fully turned on when the equipment is turned on, the outlet temperature will rise quickly, and the actual tower temperature will not rise equally.
The temperature is uneven, and it is easy to produce a sticky wall phenomenon
when the spray is started.

If the temperature is too high, it will cause damage to the active ingredient of Chinese medicine or change the properties of a certain ingredient; The temperature is too low, can not be fully dried, and the phenomenon of
sticking to the wall occurs.

Within a suitable range, the higher the inlet air temperature, the faster the solvent evaporates, and the viscous phenomenon is reduced
.

If the Chinese herbal extract contains more viscous components, the inlet air temperature and the outlet air temperature should be appropriately reduced, so that the spray drying can be carried out smoothly, because the viscosity of the carbohydrate components increases after high heat.
The phenomenon of sticky walls is generated, and the appropriate reduction of temperature can reduce the sticky wall situation
.

2.
4 Liquid supply speed The liquid supply speed and the occurrence of viscous wall phenomenon are also important
.

In the absence of other conditions, the speed of liquid supply is accelerated, resulting in droplets not being in a fluidized state, sticking to the wall or bottom
due to insufficient drying.

If you increase the liquid supply speed of the double yellow microcapsule, although it has little impact on its hygroscopicity, it will significantly reduce its dispersion rate"
.

Causes the particle size of the droplets to be too large, the drying is not enough and the wall
is sticky.

There are many factors affecting spray drying, in addition to the above factors, there are also factors such as liquid drug temperature, negative pressure size, and stability of negative pressure, so the influence
of the above influencing factors on the spray drying process should be comprehensively considered in actual operation.

3 Organic solvent spray dryer on the anti-stick wall of traditional Chinese medicine extract excipients can play its anti-sticky wall effect by improving the hygroscopicity of the material, improving the softening point of the material, enhancing the fluidity of the extract, improving the atomization effect
of the extract, and wrapping the components that are easy to absorb moisture and cause sticky walls.

Because excipients play an important role in improving the properties of traditional Chinese medicine extracts, the application of organic solvent spray dryer spray drying process is important
.

For compound extracts, due to their complex physicochemical properties, modification by a single excipient has a limited effect.
Through the combined application of a variety of excipients, it can play an anti-stick wall role
from many aspects.

For organic solvent spray dryers, appropriately increasing the temperature of the intake air El can reduce the occurrence
of sticky wall phenomenon.

The pressure of the compressed air used for spray drying should be kept constant, and fluctuations in pressure can produce serious sticky wall phenomena
.

The nozzle feed speed and the compressed air volume of the nozzle should match, and the nozzle atomization effect should be checked during normal operation to reduce the occurrence
of sticky walls.

However, by adjusting the parameters to play a sticky wall role is less than the application of excipients, the adjustment range of the parameters is also very limited
.

In view of the complexity of traditional Chinese medicine ingredients, in the entire research process of spray drying process, it is necessary to fully analyze and understand the nature of the material, through the application of excipients and the adjustment of the parameters of spray drying equipment, summarize the anti-sticky wall law, in order to solve the problem of traditional Chinese medicine sticky wall, and finally get a scientific, reasonable and feasible spray drying process
.