Spray dryer is a kind of equipment, which can complete drying and granulation at the same time. It is mainly composed of a slurry supply system, atomizer, drying tower, hot air system, exhaust gas discharge, and dust removal system, discharging, and powder conveying system.
Spray drying is the process of using a nebulizer to disperse the material liquid into fine droplets, and quickly evaporate the solvent to form a dry powder in a hot drying medium. Generally, spray drying is divided into four stages: a material liquid atomization; b fog group, and The hot drying medium is mixed in contact; c the evaporation and drying of the mist droplets; d the dried product is separated from the drying medium.
In the past, spray drying technology in China was relatively backward, productivity was not high, and product quality and production volume could not meet user needs. With the development of science and technology in recent years, China’s spray drying technology has been significantly improved, which can meet the needs of many pharmaceutical companies. However, compared with overseas spray dryers, China’s technological level needs to be improved.
The industry emphasizes that the overall level of the spray drying equipment manufacturing industry in China has shown a backward situation, most of which are caused by low-level repetitive production, including problems such as poor equipment manufacturing materials and poor processing technology.
At present, China’s support policies for automation technology and intelligence are further promoted. Based on this, if the spray dryer manufacturing industry wants to reduce the difference with overseas, it can start from the aspects of intelligent equipment, processing methods, and processing quality. Improve.
In the history of more than 100 years of spray drying, it was initially only in the production of egg powder, milk powder, detergent, cosmetics, and other small products. With continuous research, it has been used in the production of a variety of industrial ultra-fine powders and nano-powders. Widely used, such as battery raw materials in the chemical industry, white carbon black; alumina in the ceramics industry; dry granulation of drugs in the pharmaceutical field. Compared with the non-spray drying method, spray drying can effectively reduce the agglomeration of ultrafine powders. After spray drying, particles with high sphericity, good fluidity, and high fineness can be prepared to meet the requirements of specific fields.
The raw material liquid is an emulsion, a suspension, or a liquid form, which can be transported by a pump such as a melt or a paste. The product is a powder, granule, hollow ball, or pellet. Use a spray drier to spray a water content of 75% to 85% liquid into spray droplets and disperse it in a hot air stream to quickly evaporate the water to obtain a solid product. The drying time generally takes only a few seconds to tens of seconds. The sprayer is the key part of spray drying, mainly centrifugal, pressure, and airstream sprayers.