Features drying technology

Drying equipment technology has a wide service areas. Faced with a large number of industries, the physical and chemical properties of different materials, product quality and other requirements vary, drying equipment and technology is a cross-sectoral, interdisciplinary, scientific experiments have technical nature.

Typically, in the development and application of drying technology in three areas we need to have knowledge and skills. The first is the need to understand the use of the characteristics of the material to be dried and the physicochemical properties of the product. The second is to be familiar with the principle of transfer of the project, namely the principle of energy transfer transfer, heat transfer, fluid mechanics and aerodynamics pass. Means to have a third embodiment, that is capable of drying process engineering design, major equipment, electrical instrumentation control and other aspects. Obviously, these three areas of knowledge and technology does not belong to a subject area. In practice, these three aspects of the knowledge and skills but also indispensable. So drying technology is a cross-sectoral, interdisciplinary technology.

　　Although there are modern drying equipment technology development history of one hundred years, but it still belongs to the category of experimental science. Most of the current lack of technical drying equipment capable of precise scientific theory to guide practice and design methods. Practical applications, rely on small-scale test data and experience to guide or major way. The reasons for this situation are the following:

　　One reason is drying technology by relying on some of the basic disciplines (mainly transfer project is part of the scope of the subject) itself has the characteristics of experimental science. Example, aerodynamic research and development but also on "wind tunnel" test to drive, it means that it is not out of the scope of experimental science. These basic subjects of their own level of development and decisions directly affect the level of development of drying technology.

　　The second reason is that many drying process is a process of multi-disciplinary technologies intersection conducted, involving a wide range, many variables, complex mechanism. For example, in spray drying technology in the field, running track atomized droplets in the drying tower is the key to engineering design. The trajectory of the droplet with its own volume, mass, initial velocity and direction of the flow of hot air and the droplets and other surrounding flow rates. But these parameters as a result of mass transfer, heat transfer process, all the time changing. And the initial state, both the size distribution of the droplets of hot air can not be uniform. Obviously, for such a complex, changing process only with theoretical calculations for engineering it is unreliable.

　　The third reason is the type of dry material is varied, its physical and chemical properties of each is different. Different materials even under the same drying equipment conditions, the mass transfer, heat transfer rate may also have a greater difference. If not treated differently, it may result in undesirable consequences. For example, some dried herbs, although both belong to a medicine just because there is a distinction medicinal origin or harvest drying conditions will have to change, otherwise the product quality will be substandard.

　　Above three reasons determine the development and application of drying technology to a trial basis. But these features of drying equipment technology is often intentionally or unintentionally overlooked. Due to the lack of test equipment manufacturer or the type of failure (this is a common phenomenon in our country) should be done regularly to avoid drying experiment, and users lack of understanding of the characteristics of drying technology, and often give up the necessary test requirements. The end of which means the use of ineffective, or even scrapped. In our country, such examples are common, have had a value of 20 million yuan of industrial drying apparatus due to reach the requirements and the lessons to be idle. Therefore, the construction of industrial drying apparatus, especially before a larger device must be adequate, convincing test, and the test results as a basis for plant construction. This is a significant characteristic drying applications.

　　In addition, a wide range, each with a characteristic drying device also uses technology. Each technique has its own suitable application areas. In engineering practice, to select the type of drying technology applicable depending on the circumstances. This creates a significant impact on capital costs, operating costs, product quality, environmental requirements and other parties will be. For example an enterprise, silica cake is dried at once technically van were selected through drying, spray drying, rotary airflow fast drying modes. 　　　　　Eventually they realized that these three technologies have their own strengths. Van dried white carbon black production although low productivity, the labor intensity; but good quality. And after kneading the resulting rubber products high tensile strength values. Whirling airflow fast drying equipment, compact, low investment, high production efficiency, but the intensity index of the resulting rubber is among the three worst. Spray-drying production of white carbon black, product of the indicators in the middle among the three, but the product has good mobility, small dust pollution, factory operator by users and welcome features. In the 1990s, a kind of drying method is more advanced problems silica used in the production, it has been raised in our community dried debate. In fact, the three devices have their own characteristics, the choice of what type of technology depends on the user's own conditions and product requirements. Which technology is more advanced conclusion does not exist. There are many similar examples, show a wide range of drying technology, each with use features. So be careful comparison application, carefully chosen technical solutions, and by drying the test to assess the technical solution is a necessary step.