Box dryers are widely used in many industries to dry materials. However, the characteristics of different materials will have a significant impact on their drying rates in box dryers.
First of all, the form of the material is one of the key factors. For example, granular materials generally have a greater surface area to volume ratio than bulk materials. Like fine sand particles, they can contact hot air faster and conduct heat exchange in the box dryer. The moisture evaporates from its surface more easily, and the drying rate is relatively fast. For massive ores, since internal moisture needs to overcome a longer path to diffuse to the surface, and the contact area between the surface and hot air is limited, the drying process will be slower.
Secondly, the moisture content of the material and the nature of the bound water also greatly affect the drying rate. For materials with high moisture content, such as fresh fruit slices, a large amount of water evaporates in the early stages of drying, resulting in a faster drying rate. However, as drying proceeds, the proportion of bound water in the material gradually increases. These bound water are closely combined with the material molecules and require higher energy to break away. At this time, the drying rate will decrease significantly. On the contrary, some materials with low moisture content and mainly free water, such as dried grains, have a relatively smooth and fast drying process.
Furthermore, the heat sensitivity of materials cannot be ignored. For heat-sensitive materials, such as certain pharmaceuticals or biological products, excessive temperatures cannot be used in the box dryer. Because high temperatures may cause the active ingredients of the material to denature or deteriorate in quality, drying can only be performed at a lower temperature, which will inevitably reduce the drying rate. For materials with better heat resistance, such as ceramic raw materials, higher drying temperatures can be used to speed up the evaporation of water and increase the drying rate.
When using a box dryer, the shape, moisture content, bound water properties, heat sensitivity and other characteristics of the material must be fully considered. Only by formulating appropriate drying process parameters according to different material characteristics, such as temperature, ventilation volume, drying time, etc., can an efficient and high-quality drying process be achieved, which not only ensures that the drying effect of the material meets the requirements, but also avoids damage to the quality of the material due to improper drying. , improve production efficiency and product quality.
