Advantages of upper exhaust pressure spray drying tower and overview of air flow mode of spray drying tower  

Spray drying tower is a drying equipment that directly dries solution or suspension into solid particles.  Dry products can be obtained directly from the material liquid, eliminating unit operations such as evaporation, crystallization, separation and crushing, which can be continuous, automatic production and stable operation.  By adopting this drying method, the contact surface area of gas-solid phase in spray drying tower is large and the drying time is short, generally the drying time is 5 ~ 30s, which is suitable for drying heat-sensitive materials.  The quality of the dried product is good, the particle size can be 30 ~ 50μm, the fluidity and quick solubility of the product are good.  The disadvantage is that the volume of the dryer is large, the heat transfer coefficient is low, resulting in low thermal efficiency, power consumption.  

The spray drying tower can be classified into parallel flow, counterflow and mixed flow according to the gas-liquid flow direction.  According to the installation mode of the atomizer, it can be divided into up-spray down-type and down-spray up-type;  According to the structure of the atomizer, it can be divided into centrifugal type, pressure type and air flow type.  According to whether the heating gas is circulating, it can be divided into open, partially circulating and closed.  

The upper exhaust spray drying tower can reduce the amount of sewage discharge and save energy: the lower exhaust tower tower can not form a circular wind curtain, tower wall hanging powder is serious, the tower should be brushed every day.  Brush tower increase material loss and waste a lot of hot water.  It not only consumes energy but also increases the amount of pollution discharged.  When the upper exhaust tower is dry, the annular air curtain is formed in the tower to control the wall hanging powder phenomenon. The tower can be cleaned for more than ten days, so as to reduce the amount of sewage discharge, save energy, and reduce the labor intensity of workers.  

The quality of free flowing powder materials produced by the upper exhaust spray drying tower in the process of aggregation forming or granulation is improved: the particles of the material are uniform, and the larger particles and smaller particles are less.  Because the drying area of the material is high negative pressure area, the drying of the material is low temperature drying, so that the damage of various vitamins in the material is small, and the protein is not denaturated.  In addition, due to the material in the drying process of heating time is shorter than the lower exhaust tower in the high temperature area, so that its color, granularity and tonality are better.  The resulting powder contains very small amounts of dust (referred to as dust-free particles).  

The upper exhaust spray drying tower drying technology combines fluidized bed drying technology and spray drying technology, so that the shape and size of particles can be easily controlled.  

In addition, the upper exhaust pressure spray drying tower is often used as spray drying aggregation or spray drying granulation.  The drying process can be completed while keeping the powder temperature low. Another important function is that it can be applied to the drying forming of heat sensitive products.  The upper exhaust spray drying tower is one of the successful designs of spray drying equipment.  

The upper exhaust pressure spray drying tower can be applied to many kinds of products, especially those products which are difficult to be powder formed by traditional drying technology.  

Can dry many other equipment can not process thermoplastic and hygroscopic strong products.  It is an ideal drying equipment for heat-sensitive products because the temperature of particles is always low during the whole drying process.  Drying is done at a lower exhaust temperature, so it is good for energy use.