Each type of drying equipment has its own specific application range, and each material can find several drying equipment that can meet the basic requirements, but only one of them is most suitable. If the selection is not appropriate, in addition to the unnecessary one-time high procurement cost, the user has to pay a heavy price throughout the lifetime, such as low efficiency, high energy consumption, high operating cost, poor product quality, and even equipment. It can't run normally at all.
The following are the general principles for the selection of drying equipment. It is difficult to say which one or which items are the most important. The ideal selection must be based on its own conditions, and sometimes compromises are necessary.
1. Applicability ------- Drying equipment must first be applicable to specific materials and meet the basic requirements for drying of materials, including good handling of materials (feed, transport, fluidization, dispersion, transfer) Heat, discharge, etc.), and can meet the basic requirements of processing volume, dehydration amount, product quality and so on.
2. High drying rate---only in terms of drying rate, the material is highly dispersed in hot air during convection drying, the critical moisture content is low, the drying speed is fast, and the same convection drying, the drying method has different critical moisture content, so The drying rate is also different.
3. Low energy consumption ------- Different drying methods have different energy consumption indexes. Generally, the thermal efficiency of conductive drying can reach 100% theoretically, and convection drying can only be about 70%.
4. Saving investment-----Drying equipment that performs the same function, sometimes its cost difference is very different, should choose the lower one.
5. Low operating costs - equipment depreciation, energy consumption, labor costs, maintenance costs, spare parts costs, etc. should be as low as possible.
6. Prefer the drying device with simple structure, sufficient supply of spare parts, high reliability and long service life.
7. Meet environmental protection requirements, good working conditions and high safety.
8. It is best to make the drying experiment of the material before the selection, and to understand the drying device (excellent and shortcomings) that have been used in similar materials, which is often helpful for proper selection.
9. Not relying entirely on past experience, focusing on absorbing new technologies and listening to expert opinions.
At present, the low level of automation of domestically produced drying equipment and the backwardness of control methods are common problems. At the current level of automation, it is not difficult to solve the control problem in drying equipment, but the most lacking is the reasonable combination of automatic control technology and drying equipment. Different materials have different requirements for the dryer. Similarly, different materials have different requirements for control methods. The role of automatic control in dryers is well known, but its one-time investment is also a major concern, and sometimes the investment in control equipment exceeds the investment in the mechanical part of the dryer. It is also a subject that should be studied at present to determine the appropriate control method for the specific drying project in order to determine the control plan reasonably for the dryer and drying process.
In addition, attention should be paid to the amplification study of drying equipment. Amplification involves disciplines such as fluid mechanics, mechanics, thermodynamics, heat transfer, materials science, dust removal, corrosion protection, electrical appliances, and control. Some problems are likely to occur during the enlargement process. Therefore, the amplification of the drying device is by no means a simple geometric enlargement. In this respect, it depends to a large extent on industrialization experience, mastery of material properties and knowledge of drying equipment. The phenomena that may occur during the amplification process should be reasonably and objectively predicted, and the corresponding scheme can be proposed. The so-called research amplification effect is to grasp the dry theory and drying technology while paying attention to accumulating practical experience and summing up lessons.