A vertical preheater is a key component of active lime rotary kilns, cement rotary kilns, and metal ore rotary kilns. Its primary function is to transport limestone, cement raw material, and metal ore fines fed from above into the preheater. Simultaneously, the high-temperature exhaust gases (1150°C) emitted after calcination in the kiln are used to uniformly preheat the materials to approximately 800°C. During the preheating process, the limestone, cement raw material, and metal ore fines decompose within the preheater before being pushed into the rotary kiln by hydraulic push rods for calcination. This calcination process significantly shortens kiln calcination time and achieves high production yields.
A vertical preheater system consists of six main components.
1. Upper Feed System: This primarily includes the upper hopper and discharge pipe. The discharge method and structure ensure a safe and airtight feed system into the preheater, preventing cold air from entering the preheater. Continuous or intermittent feeding can be achieved using a bar valve.
2. Preheater Main Body: This is the most critical component for ensuring the material is preheated to approximately 900°C. It consists of the preheating chamber, suspension assembly, and refractory brick lining (this item is not included in the scope of equipment design and manufacture). This component is primarily metal, with some materials selected for their specific needs. Heat-resistant steel, capable of operating at temperatures of 1000-1100°C, is used. Furthermore, the refractory brick lining features a novel design and excellent sealing properties, ensuring uniform preheating of the material within the preheater and reaching the preheating temperature.
3. Pusher Mechanism: This primarily comprises a pusher head, frame, and connecting rods. The pusher head is cast or welded from heat-resistant steel and is designed to withstand high temperatures. Using an electronic control and hydraulic system, each hydraulic pusher pushes the material sequentially according to an automatic control program.
4. Hydraulic System: This primarily includes the oil tank, oil pump, motor, solenoid valve, and hydraulic oil pipes. Its primary function is to control the pusher mechanism and complete the pushing action.
5. Lower Charging Chamber: This primarily includes the chute, charging chamber body, and charging spout. Its primary function is to guide preheated materials into the rotary kiln for calcination.
6. Frame: This primarily includes columns and ring beams, supporting the preheater's upper structure.
Technical parameters of vertical preheater in lime rotary kiln equipment:
| Design capability (T/D) | 150 | 200 | 300 | 400 | 600 | 800 |
| Preheater | Four push heads | Six push heads | Eight push head | Eight push head | Twelve push heads | Sixteen push heads |
| Rotary kiln specifications | φ2.5X40 | φ2.8X42 | φ3.3X52 | φ3.6X56 | φ4.0X60 | φ4.3X65 |
| Effective volume (m³) | 142 | 190 | 329 | 433 | 590 | 736 |
| Calcination temperature (m³) | ≤1250 | ≤1250 | ≤1250 | ≤1250 | ≤1250 | ≤1250 |
| Cooler | LS-3X3 | LS-3X3 | LS-3.6X3.6 | LS-3.6X3.6 | LS-4X8 | LSF-4.7X8.9 |
| Fuel | Gas, oil, pulverized coal | Gas, oil, pulverized coal | Gas, oil, pulverized coal | Gas, oil, pulverized coal | Gas, oil, pulverized coal | Gas, oil, pulverized coal |
| Heat consumption | 1200±100 | 1200±100 | 1200±100 | 1200±100 | 1200±100 | 1200±100 |
