When the sawdust dryer is in operation, the drying process of the material mainly depends on the heat transfer of the drying medium and the water in the material becomes steam and diffuses to the drying medium. The faster the speed of these two processes, the greater the drying speed. Therefore, the drying speed of the sawdust dryer is affected by which factors, and it is necessary to talk about the heat transfer rate and the diffusion speed.
1. The higher the temperature of the drying medium, the greater the drying speed. Because the temperature difference between the drying medium and the material is larger, the heat transfer rate is larger. If the high temperature flue gas is used for direct drying, a better heat transfer effect can be obtained. Therefore, as long as the process properties of the materials and drying equipment allow, high temperature flue gas should be used as much as possible.
2. The lower the relative humidity of the drying medium, the faster the water vaporization, so the drying speed will be larger. For example, when using flue gas as the drying medium, the humidity and the humidity of the air and the moisture of the fuel during combustion and Related to the amount of hydrogen. Increasing the amount of exhaust air can eliminate the drying medium which is increased in humidity after drying, and replace it with a drying medium with a lower humidity.
3. The larger the contact surface between the drying medium and the material, the higher the drying speed. Therefore, the solid matter is broken during drying (the surface area can be increased, the internal diffusion path can be shortened, the diffusion resistance can be reduced), or the material can be dried in a suspended state, and a lifting plate or a grid plate can be added in the rotary dryer. It can increase the contact area between the drying medium and the material, increase the drying speed and shorten the drying time.
In the actual production process,slow drying speed will lead to low output,and increasing the thermal efficiency and output of the wood chips dryer has always been the focus of attention. Therefore, we can improve the drying efficiency and ensure the drying output from the three points mentioned above.