Drying medium - Residual heat from finished bricks in a baking oven. The drying medium is sent to the drying chamber by the blower, and the heat is transferred to the blank surface by heat exchange. When the blank surface is heated, the heat is transferred to the inside of the blank. Diffusion and conduction are heat transfer processes. When a blank surface is heated, the water on the surface evaporates and evaporates. Due to the different moisture content of the material, the moisture inside the blank will move to the surface and then volatilize from the surface until the blank dries, a heat transfer process. The heat source of the tunnel drying chamber, that is, the heat energy used for drying, is usually the hot air formed by the waste heat of the brick body of the tunnel roasting kiln, which is usually called the waste heat in the furnace.

During operation, the smoke and heat are separated. Complete separation of flue gas from heat means that kiln flue gas goes directly into the flue gas treatment equipment. The waste heat in the kiln is directly used to dry the green billet. The principle is the residual heat energy of the kiln tail brick. Radiate and heat the surrounding air to produce residual heat. 

(no waste heat) gas does not need to install flue gas treatment equipment, after drying directly discharged; The flue gas pollutants in the kiln have small air volume, high temperature, low humidity and large consumption. Equipment should be treated before reaching standard consumption. In enterprises, the exhaust pipes of general drainage emit more or less black smoke (blue smoke) that does not meet the emission standards. The reason is that the bricks consume less carbon in a tropical climate, the carbon in the forging and burning areas is not burned, or the calorific value of the billet is high, and the kiln speed in the kiln is very fast. 

As a result, more carbon remains in the billet, resulting in residual carbon in the billet. The bricks in the cooling zone are still burning, inevitably producing harmful substances such as carbon monoxide, carbon dioxide, soot and sulfates. These harmful substances are mixed with water vapor in the drying chamber. When concentrations reach a certain level, smoke particles visible in the adult eye are collected and emitted to create a persistent black smoke.