Introduction
Lime rotary kiln is also called roller rotary kiln. To make sure it’s air leakage coefficient is less than 10 percent, lime rotary kiln adopts advanced structure and reliable combined scale-like seal in both ends. It also uses composite refractory to reduce the loss of heat radiation.
Lime Rotary Kiln Operating Principle
Lime rotary kiln’s whole process is well-regulated. The limestone is stored in a silo. Then be carried in preheater’s top silo by hoist. There are two-level gauges in silo to control the feed amount. They distribute limestone evenly into different preheater’s rooms through feed pipe.
Limestone is decomposed 30% when it is heated to 900 ℃ by hot smoke at 1150 ℃. After being pushed into the kiln by a hydraulic push rod, lime is resolved into CaO and CO2. Then be cooled down to 100℃ by cold air in cooler and then be discharged.
After successively through vibrating feeder, chain bucket conveyor, bucket elevator and tape conveyor, lime eventually is sent into lime finished product library. Then the clients decide whether screening is needed.
Lime Rotary Kiln Technical Characteristics
●Lime rotary kiln has advanced structure. Vertical preheater effectively magnifies the warm-up effect. The decomposition rate of preheated lime can reaches from 20% to 25%.
●Lime rotary kiln has a reliable combined scale-like seal. The scale-like seal in both ends guarantees its air leakage coefficient is less than 10 percent. It also uses composite refractory to reduce the loss of heat radiation.
●Lime rotary kiln has a vertical cooler. The filled cooler with dividable ventilation cools down the lime into 80℃ making it easier to be transported and stored. And it can preheat the secondary kiln air up to more than 700℃, which reduces the need for moving parts and special materials.
Lime Rotary Kiln Design Requirements
- Preheated and precalciner’s ratio of length to diameter(L/D) should be 11-16.
2. The specification of the lime rotary kiln should be in accord with the need for output combined with the actual situation of fuel condition, preheater, precalciner and cooler.
3. Pay attention to the details of the lime rotary kiln below. The gradient of preheater and precalciner should be 3.5%-4%. Precalciner’s maximum speed should be 3.0-3.5r/min while preheaters should be 2.0-2.5r/min. The speed range should be 1:10.
4. Lime Rotary Kiln’s cooling method better be forced air cooling.
5. There has to be a step to detect the temperature of lime Rotary Kiln’s burning belt.
6. Better adopt step-less variable speed motor as lime Rotary Kiln’s main motor. Set up a series of auxiliary drive and backup power.
Lime Rotary Kiln Outstanding Advantages
- Lime rotary kiln’s main drive system uses Ac frequency conversion control technology. It has superiority in all energy-saving and environmental protection, efficiency and steady operation.
- Lime rotary kiln’s optimized the overall structure of the kiln head and kiln tail according to the characteristics and calcination requirements of lime. It successfully solves the pervasive problem in this sector such as dusk leak so makes a smother deliver.
- Lime rotary kiln leaves the specific length of gap between wheel belts and kiln according to the thermodynamic calculation analysis system to make sure they closely fit in the work state. This method effectively raises kiln’s rigidity meanwhile prevents the necking phenomenon.
- Lime rotary kiln’s quality of production is guaranteed because of even heat and low over-burn rate.
- Lime rotary kiln sets up a temperature-measurement interface, which is convenient to plug in temperature measuring devices to reach fully automated inspection.
- Lime rotary kiln’s process of preparation is flexible. The high-temperature smoke in vertical preheater can be fully used to turn lime into an initial decomposition state. The vertical cooler can be put in kiln heat to instantaneously cool down lime, so product activity is raised and transportation is more convenient.
Kiln Operation Parameters
| Design Capability (t/d) | 150 | 200 | 250 | 300 | 350 | 400 | 500 |
| Production | Activated Lime Lightly Burnt Dolomite | Activated lime lightly burnt dolomite | Activated lime lightly burnt dolomite | Activated lime lightly burnt dolomite | Active Lime | Active Lime | Active Lime |
| Specification (m) | Φ2.5×40 | Φ2.8×42 | Φ3×46 | Φ3.2×50 | Φ3.5X54 | Φ3.6X5 | Φ3.8X58 |
| Effective Volume | 142 | 190 | 235 | 292 | 390 | 430 | 505 |
| Ignition Temperature | 1350/1250 | 1350/1250 | 1250/1350 | 1350/1250 | 1350 | 1350 | 1350 |
Lime Rotary Kiln Arrangement Requirement
- The center height of lime rotary kiln should accord to coolers.
- Foundation pier of the lime rotary kiln should follow these requirements: The size of the rotary kiln should be based on coal kiln’s size. The horizontal distance between the foundation pier better is calculated after thermal expansion. Processing axial thermal expansion calculation should sets the center of the wheel belt as a benchmark and expands to both ends. The slope of the foundation surface should be equal to kilns. The base hole should be vertical to the foundation surface.
- The distance among lime rotary kiln should follow these requirements: Accord to the kiln head and kiln tail’s placement requirements. Be convenient to operate and repair. Consider the central control room’s placement.