In waste heat recovery dryer During the research process of powder in waste heat recovery dryers, it was found that regardless of whether the powder is in a fluidized bed state or undergoing a collection operation, the large amount of dust generated in the waste heat recovery dryer can easily cause electrostatic sparks. If there are many electrostatic sparks, it can easily cause an explosion. Therefore, if the selected material is easy to generate dust when put into the dryer, then the possibility of dust explosion needs to be prevented. Especially if the material contains combustible components, more attention should be paid to prevention, because the possibility of dust explosion will be greater in this case.

　　Dust explosions in waste heat recovery dryers mainly occur because if the dust particles suspended in the dryer are in sufficient contact with the oxygen in the air, under certain conditions, they will instantly complete the oxidation reaction and release a large amount of heat in the reaction, leading to high temperature and high pressure. Generally speaking, when combustible solids burn in the air, they release energy and produce a large amount of gas. Because the dryer is a closed space, the speed of energy release is relatively more violent, and the power of the explosion will also be greater.

　　Therefore, for the powder of the same solid material, the smaller the particle size, the larger the surface area, and the faster the combustion diffusion speed. If the particle size of the solid is very fine, it can be suspended in the waste heat recovery dryer. Once ignited by a fire source, it can release a large amount of energy in a very short time. If this energy cannot be dissipated to the surrounding environment, causing the gas in the unit space to heat up and expand, and causing the internal pressure of the dryer to increase instantaneously, this will increase the risk of explosion. On the other hand, the combustion of powder will produce a large amount of gas, forming local high pressure in the system, which will also lead to explosion and heat propagation.

　　Waste heat recovery dryers usually perform drying operations on materials in a high-frequency electric field, so they are also called high-frequency dryers. Because the dielectric loss of wet materials in a high-frequency electric field will generate heat, using a waste heat recovery dryer to dry wet materials is also called dielectric heating drying. From the perspective of molecular motion, the dried material is in a high-frequency electric field. Under the action of a high-voltage alternating electric field, the arrangement of water in the wet material changes with the change of the electric field, the molecules swing or vibrate, the vibration of adjacent water molecules produces friction, produces a thermal effect, heats the material, evaporates water, and thus achieves the purpose of drying.

　　Relatively speaking, because the drying of materials using a high-frequency electric field uses a constant current converter, so that direct current can be converted into high-frequency alternating current in the equipment, the drying process will be more stable, and it is not easy to cause explosions. Therefore, in order to prevent explosions, it is recommended that when using a waste heat recovery dryer, you should try to use its high-frequency electric field to dry the materials.