Energy efficiency and drying temperature of horizontal spray dryer
At present, among many drying equipment, the horizontal spray dryer is one of the dryers with high output value, each set of which ranges from several hundred thousand to several million. There are many professional manufacturers of horizontal spray dryers in Wenzhou, Shanghai, Wuxi, Jiangyin, Xining and other places, which provide users with hundreds of sets of spray drying equipment every year. In terms of research, in the academic papers of each national drying conference, the research content of spray drying technology is the first of all models. The imperfection of theory and the universality of application have always attracted the attention of a large number of researchers. The horizontal spray dryer has a fast drying speed, and the surface area of the liquid material is greatly increased after atomization. In the hot air flow, 95% -98% of the water can be evaporated instantly, and the drying time is only a few seconds. It is especially suitable for drying heat sensitive materials. The horizontal spray dryer has good uniformity, fluidity and solubility, high product purity and good quality. The production process is simplified, the operation control is convenient, and there is no need to crush or screen after drying, reducing the production process and improving product purity. However, the unit weight heat consumption of the product is high, and the investment required by the enterprise is relatively large, which is generally unaffordable for small and medium-sized enterprises.
Therefore, the main measures to reduce the consumption of spray drying equipment Since the energy consumption in the spray drying process directly affects the economic benefits and development prospects of enterprises, industry experts have put forward many measures to save energy and reduce consumption in the spray drying process. Through the improvement of drying media, thermal cycle and other links, further improve the energy saving effect of spray drying equipment, reduce costs, improve economic benefits, and better serve customers.
Difficulty in drying materials containing organic solvents in horizontal spray dryers: generally, organic solvents are flammable and explosive. Explosion proof closed laboratory horizontal spray dryers enable materials to circulate in a closed drying system. The whole system is filled with inert gases (such as nitrogen or argon), which can avoid the contact between organic solvent gas and external oxygen and ensure safe production. The horizontal spray dryer adopts a safe nitrogen (or other inert gas) closed circulation mode. The whole system is closed, and the oxygen concentration is monitored online. Once the oxygen concentration in the system reaches 2%, the system will automatically shut down and give an alarm. It is a small horizontal spray dryer dedicated to organic solvents in the laboratory with good safety and easy operation. It can treat flammable and toxic solvents and dry easily oxidized substances through nitrogen closed circulation and complete solvent recovery. Moreover, due to the low boiling point of organic solvents, low-temperature drying can be used to dry substances that are prone to thermal denaturation.
Influence of drying temperature of horizontal spray dryer: during the operation of horizontal spray dryer, it is very important to determine the temperature of hot air for drying entering the tower (hot air temperature) and the outlet temperature (exhaust air temperature). The exhaust temperature is related to the moisture content of the product and should be determined according to the allowable moisture content of the product. The higher the temperature of the hot air, the higher the thermal efficiency and the better the economy. However, excessively high hot air temperature can cause product quality deterioration, so the hot air temperature must be appropriately increased while ensuring product quality. The hot air temperature of horizontal spray dryer will have a significant impact on the bulk density of the product. High temperature hot air tends to produce low bulk density due to its rapid drying effect, which hardens the surface of particles and expands residual moisture, promoting the formation of balloon shaped hollow particles. If high bulk density (low specific volume) or solid particles are required, high-temperature hot air should not be used in contact with newly formed droplets during design. In the drying of chemical drugs, the hot air temperature can reach up to 538 ℃, and the product particles are large. It can be observed that residual steam has sufficient pressure to blow the outer surface into voids. In spray drying of food, the temperature of hot air generally does not exceed 177 ℃, so the initial diameter of hollow particles is not as large as that of chemicals.
