In response to the national policy of increasing production and saving energy, when designing a drying line, it is necessary to seek reasonable equipment for the drying system; for existing production lines, new technologies should be used to complete the supporting drying lines. The following is an introduction to the two major factors that can save energy and increase production of lignite dryers.
1. Reduce lignite particle size and maintain uniform feeding
The finer the particle size of the material, the better the uniformity of the flow, and the smaller the stagnation tendency in the system; on the other hand, the smaller the particle size, the larger the heating area, and the higher the transpiration intensity. On the contrary, large particles of material can easily form air film layers and hard layers, which hinder the heat and mass transfer of the inner material. Uniform feeding is the condition for achieving uniform material flow. On the one hand, it can keep the balance of the heat load of the lignite dryer and the stability of the thermal principles, make the moisture of the dried materials uniform, and heat the hot blast stove and other loads, thereby improving the use of the lignite dryer and electric precipitator. service life; on the other hand, it can also make the exhaust gas temperature easy to grasp and control. Mechanical feeding usually uses the method of "elevator + central silo + disc feeder" or "belt conveyor + double flap discharge valve". The former is suitable for materials with low moisture and low viscosity, while the latter is suitable for materials with high moisture and high viscosity.
2. Improve the feeding method of lignite dryer
Almost all lignite dryers use inclined chute feeding. Due to the high furnace temperature and large load changes, the slide tube is eroded and oxidized by the heated flue gas, causing serious deformation and damage, and replacement is quite troublesome. More serious bending and deformation of the slide pipe will often pry the furnace roof or the coal slime dryer fire sealing ring, causing air leakage and material leakage, which will greatly reduce the thermal efficiency and service life of the coal slime dryer. No matter whether the slide pipe is made of steel pipe or cast iron pipe, the problem of short service life cannot be solved well. In order to extend the service life of the feeding pipe of the coal slime dryer, the inclined chute can be changed to the "straight pipe + lower trough plate" method. The upper section is a straight pipe, and the straight pipe is built into the furnace wall to avoid high-temperature oxidation. and flushing of hot flue gas.
