Quicklime Production Equipment
A shaft kiln for calcining limestone into high-quality quicklime (CaO). Fuel: natural gas or pulverized coal, capacity 80-1,200 t/d. Low heat consumption, uniform calcination, compact footprint, and lower capital cost than rotary kilns — ideal for medium-capacity lime plants.
Product Overview
The vertical lime kiln — also known as a shaft kiln — is a vertical furnace used to calcine limestone (CaCO3) into quicklime (CaO) by heating it to temperatures of 1,100-1,300°C. In this process, limestone undergoes thermal decomposition: CaCO3 → CaO + CO2. The resulting quicklime is a vital industrial material used in steelmaking, construction, chemical processing, environmental treatment, water treatment, and cement production.
Unlike a rotary kiln, which rotates a long cylindrical shell, the vertical lime kiln is a stationary vertical shaft. Limestone is charged from the top and moves downward by gravity through three zones: the preheating zone (where limestone is preheated by rising exhaust gases), the calcining zone (where fuel combustion reaches 1,100-1,300°C and decomposition occurs), and the cooling zone (where quicklime is cooled by incoming combustion air). This counter-current heat exchange gives the vertical kiln its excellent thermal efficiency.
LIMING vertical lime kilns are engineered for capacities from 80 to 1,200 tons per day and can be fired with natural gas, pulverized coal, coke oven gas, or heavy oil. Modern designs include double-shaft (parallel flow regenerative) configurations that achieve the lowest heat consumption in the industry. For medium-capacity lime plants, the vertical kiln offers a compelling combination of low investment, low operating cost, and high product quality.
Key Benefits
Superior energy efficiency, product quality, and economy compared to rotary kilns for medium-capacity lime production.
The counter-current shaft design preheats limestone with rising exhaust gases and preheats combustion air with cooling quicklime. This regenerative heat recovery reduces fuel consumption to 3,800-4,200 kJ/kg — 25-30% lower than rotary kilns.
The shaft kiln's uniform material flow and controlled temperature profile ensure consistent calcination. Product quicklime has high activity (reactivity), low CO2 residual, and uniform quality — with overburned and underburned material minimized.
The vertical design occupies a much smaller area than a rotary kiln of equivalent capacity. Lower equipment weight, simpler civil works, and fewer auxiliary systems translate to 30-40% lower capital investment — ideal for medium-capacity plants.
The vertical kiln has no rotating shell — fewer moving parts means lower maintenance and longer refractory life. Automated PLC control with temperature and pressure monitoring ensures stable, hands-off operation with minimal operator intervention.
Comparison
Choosing the right kiln type depends on capacity, feed size, and product requirements.
| Parameter | Vertical Lime Kiln | Rotary Kiln |
|---|---|---|
| Capacity Range | 80-1,200 t/d | 300-2,000+ t/d |
| Heat Consumption | 3,800-4,200 kJ/kg | 5,000-5,500 kJ/kg |
| Capital Cost | Lower (baseline) | 30-50% higher |
| Footprint | Compact, vertical | Large, horizontal |
| Limestone Feed Size | 40-100 mm (uniform) | 10-50 mm (flexible) |
| Product Quality | Uniform, high activity | Good, slightly variable |
| Moving Parts | Few (stationary shaft) | Many (rotating shell) |
| Maintenance | Low | Moderate to high |
| Best For | Medium-capacity lime plants | Large-capacity / fine feed |
Technical Data
Representative models. Custom designs available for specific fuel types and capacity requirements.
| Model | Capacity (t/d) | Shaft Diameter (m) | Effective Height (m) | Fuel Type | Heat Consumption (kJ/kg) | CaO Activity (ml) |
|---|---|---|---|---|---|---|
| VLK-80 | 80 | 2.5 | 14 | Gas / Coal | 4,200 | ≥320 |
| VLK-150 | 150 | 3.0 | 16 | Gas / Coal | 4,100 | ≥340 |
| VLK-300 | 300 | 3.8 | 18 | Gas / Coal | 4,000 | ≥360 |
| VLK-500 | 500 | 4.5 | 20 | Gas / Coal | 3,950 | ≥370 |
| VLK-800 | 800 | 5.2 | 22 | Gas / Coal | 3,900 | ≥380 |
| VLK-1000 | 1,000 | 5.8 | 24 | Gas / Coal | 3,850 | ≥380 |
| VLK-1200 | 1,200 | 6.2 | 26 | Gas / Coal | 3,800 | ≥390 |
* Specifications are for reference only. Heat consumption and product quality depend on limestone properties, fuel type, and operating conditions. Contact LIMING for custom sizing.
How It Works
The vertical lime kiln operates on a counter-current principle: limestone moves downward by gravity while hot combustion gases flow upward. This creates three distinct thermal zones within the shaft, each performing a specific function in the calcination process.
Frequently Asked Questions