The vertical preheater was introduced from abroad in the late 1970s. It was initially used for calcination of limestone in large steel plants, and then promoted by the domestic non-ferrous metal research institute, and now used for calcination of dolomite in the magnesium industry. The vertical cooler, rotary kiln, and bag filter form a calcining system, which is an energy-saving and environmentally friendly product, which saves energy for the country and complies with industrial policies.

Vertical preheater refers to a vertical preheating device used to preheat refractory raw materials. It has the characteristics of reasonable structure, high thermal efficiency and high level of automation, but it cannot make full use of scraps (requiring feed particles of 18-50mm) and raw materials with poor thermal stability. The vertical preheater is used in conjunction with the rotary kiln to preheat active lime or dolomite.

The working principle is as follows:

The raw materials enter the flue gas material isolation cover from the feeding chamber, and are evenly distributed in the annular stacking space between the two cylinders of the top heater along the conical surface of the central distribution cone. The hot flue gas from the rotary kiln at 900-1000°C enters the entire section of the annular stacking space through the gas collection chamber, and flows through the material layer in the opposite direction toward the feeding direction for sufficient heat exchange. The materials preheated to 600°C are pushed into the kiln in turn by means of various push rod unloaders. To achieve a uniform feeding mouth. After the heat exchange, the flue gas whose temperature drops to about 300°C is discharged into the atmosphere through the fume extractor of the electrostatic precipitator.

The advantages of the vertical preheater are:

1. The push head of the rotary kiln preheater and the key parts of the body are made of heat-resistant steel, which can work normally at a high temperature of 1000～1100℃ and have a long service life.

2. The refractory brick lining of the preheater of the rotary kiln has a novel structure design and good sealing, which can ensure that the materials are evenly preheated in the preheater and reach the preheating temperature.

3. The rotary kiln preheater effectively recovers the heat taken away by the exhaust of the kiln tail flue gas, which improves the fuel utilization rate of the system and is also conducive to dust removal.

4. The calcination system of the rotary kiln preheater adopts the vertical preheater, which can shorten the length of the rotary kiln and reduce the heat loss on the surface of the rotary kiln and the floor space.

5. The rotary kiln preheater has good comprehensive benefits. After adopting the vertical preheater system, the production capacity can be increased by 30% and the thermal efficiency can be increased by 40%.

The above is the brief introduction about the preheater. The selection is usually matched with the rotary kiln and carried out under the guidance of professional manufacturers.