1, material form The selection of drying equipment is mainly determined according to the shape of the material to be dried. The shape of the material not only determines the drying method, but also has a great influence on the drying efficiency, drying quality, drying uniformity and feeding and discharging devices of the dryer. Therefore, as the process allows, the materials to be dried should be pretreated as much as possible by crushing, sieving, and cutting. Therefore, drying equipment is not only a matter of selection, but also a scientific drying process should be established to achieve satisfactory results. 2. Factors affecting the production capacity of the dryer Due to the same drying method, the heat energy consumed by drying and dehydrating one kilogram is basically the same, and the capacity of the heat source (hot air stove, steam radiator, etc.) of the dryer is also certain, so the main technical index of the dryer--drying ability is often The amount of dewatering per hour (or the maximum amount of dewatering) is based on. This indicator is measured under certain conditions, such as wet material type, initial moisture content, final moisture content, hot air temperature, ambient temperature and humidity, and the like. As long as one of the conditions changes, it has an impact on the production capacity of the dryer, and sometimes the impact is still large. The following are explained separately. (1) Wet material types Wet material type refers here to the combination of material and moisture. The wet material can be divided into 1 capillary porous material, and the moisture is mainly combined in the material by capillary force, such as sand, silica, activated carbon, ceramics, etc., the bonding strength between water and material is small, drying is easy; 2 colloid The combination of materials, moisture and materials is dominant, such as glue and flour dough. The material generally exhibits high viscosity, and the combined strength of moisture and material is large, and drying is difficult. 3 Capillary porous colloid materials have more than The nature of the two types of materials, such as peat, clay, wood, fabric, grain, leather, etc., is the most diverse, but the form of water combination between such materials is also different, which determines the difficulty of dehydration under the same conditions. Are not the same. The shape of the material also has a great influence on the drying, such as granular materials, the particles are much harder to dry than the particles, and the large blocks are smaller in thickness than in the thick ones and easy to dry. (2) Moisture content of wet materials Moisture content (wet content) is the percentage of moisture in the total weight of the wet material. m= W×100 = W×100 (%) GGo+W Where: W - moisture weight; G - wet material weight; G 0 - dry material weight. The initial moisture content refers to the moisture content of the wet material before entering the dryer. Usually, the wet material can work in the dryer. The higher the initial moisture content, the more sufficient the dewatering capacity exhibited by the dryer. Conversely, the higher the initial moisture content, the higher the final dewatering capacity of the dryer when the final moisture content is constant, but the dry material yield decreases. (3) Final moisture content Generally, the drying section is in the slow-drying stage. The lower the final moisture content is, the more difficult the drying is. The longer the drying time is required, the lower the thermal efficiency, and therefore the yield. (4) Hot air temperature Hot air temperature, or drying medium temperature, is one of the most sensitive conditions in drying. The higher the hot air temperature, the more heat energy is contained, and the lower the relative humidity of the hot air, the stronger the ability to absorb water and carry moisture, which is very favorable for drying, and the drying heat efficiency is also high. In many drying equipment, when the other conditions are constant, the dewatering capacity of the dryer is substantially proportional to the change in hot air temperature. When selecting the drying equipment, it is necessary to have sufficient data for the ultimate temperature of the damaged material. When the material permits, try to select the high temperature medium. In particular, many drying methods, especially rapid drying, the temperature of the dried material is much lower than the drying medium temperature. For example, the hot air temperature of the airflow dryer is as high as 250 ° C or higher, and the discharge temperature is generally below 60 ° C. . (5) Ambient temperature and humidity Here mainly refers to the influence of weather changes on drying. Generally, the dryer is heated by the atmosphere as the drying medium. The higher the temperature of the atmosphere, the lower the humidity, the more favorable it is to dry, while the southern spring and summer, the rain is damp. The high humidity of the air is not conducive to the performance of the dryer and affects the output.