The industry said that in operationSpray dryerIt is very important to stop correct operation and understand all aspects of equipment performance and possible problems. It is also the key to ensure the life of equipment and the stability of enterprise operation. Among them, wall sticking is an obstacle.Spray dryerA prominent problem in normal operation, solid preparations(Especially traditional Chinese medicine)The spray drying process is particularly obvious. Material adherence is not only not conducive to the collection operation, but also over time, sensitive adherent materials will degenerate into substandard materials. In order to abolish the stickiness phenomenon, many operators try to start from the point of view of technology, including the selection of suitable solvents, the addition of accessories, the change of process parameters, etc. But these methods have little room to adjust, so it is necessary to seek the basic treatment plan from the point of view of equipment.
Spray dryerSpray is used to spray the material into droplets and disperse them in hot air. The material is in contact with the hot air in the way of parallel flow, countercurrent or mixed flow, so that the water evaporates quickly and reaches the drying purpose. The spray drying method can save concentration, filtration, smashing and other unit operations, and has short drying time, good activity and instant solubility, so it is widely used in medicine and other industries.
Experts at home and abroadSpray dryerThe problem of wall adhesion and agglomeration in drying process has been discussed. It is believed that wall temperature is the main reason for wall adhesion. There are three common phenomena in spray dryer: sticky wall. The reason is that the spray droplets have contacted the wall before they reach the surface drying, so they stick to the wall. The location of the wall is usually on the plane of the spray droplets'trajectory, which is related to the structure of the atomizer and the movement state of hot air in the tower; the hot melting sticky wall of low melting point materials. The reason is that the material melts at the beginning of the melting point at a certain temperature and sticks to the wall; the surface of dry powder adheres. Dry powder always touches the wall in limited space, which can not be prevented, but such sticky wall is usually not thick. It can be shaken only by air blowing or quiet knocking. The simple treatment method is inner wall polishing, which can deal with this problem at a certain level.
After finding out the causes of stickiness, the industry lists five ways to avoid stickiness:
OneA clip drying tower is used, in which air is used to cool the wall so that the wall temperature can be kept at a constant level.Fifty℃Following
TwoThe secondary air cooling tower wall is introduced tangentially through the swirl section of the tower wall.
ThreeAn air broom consisting of a row of nozzles is installed near the wall of the tower and rotates slowly along the wall of the tower.
FourAdding air hammer to the tower wall and forcing the sticky wall material to be separated by hammer knocking.
FiveThe polishing of the inner wall of the tower can also reduce the sticky wall by increasing the processing accuracy of the equipment.
In addition to controlling the above five phenomena to avoid stickiness,Spray dryerCleaning and maintenance methods also need to be controlled. We understand that the current domestic pharmaceutical industry is developing well, and the demand for medical equipment is increasing, as an important pharmaceutical equipment.Spray dryerIn the new environment, there will be more challenges. Of course, in addition to meeting the needs of materials,GMPIn addition to requests for energy conservation and consumption reduction,Spray dryerThe manufacturer also needs to coil up the consumption process to stop innovative research and development, and to separate the conditions of customers to stop improving promotion.
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