Rotary Lime kilns introduction
Lime rotary kiln refers to rotary calcining kiln (commonly known as rotary kiln), which is a dynamic calcination mode and belongs to the category of building materials equipment. Its main advantages include large production capacity, noiseless work, and low comprehensive energy consumption. As the main processing equipment for processing lime, it has very high industrial utilization value, so its current demand is very high. The uses of lime are very extensive. Commonly used in many fields such as construction, building materials, metallurgy, chemical industry, light industry, environmental protection, medicine and agriculture. Especially in steelmaking, ironmaking, sintering, copper, aluminum smelting and other industries, it has played a very important role in using lime as a slagging agent, solvent or sintering material.
Processed Materials: Active lime and limestone, dolomite.
Applications: Cement industry, chemical industry, building material industry, metallurgy industry, papermaking etc.
Capacity: 50-1000TPD.
The rotary active lime kiln has advanced structure and stable operation. The vertical preheater with low pressure loss of our company can effectively improve the preheating effect. The decomposition rate of limestone after preheating into the kiln can reach 30%. Gas-fired, coal powder or coal-gas mixed firing, the finished lime has high activity. This type of rotary kiln is suitable for metallurgy, chemical industry, building materials, papermaking and other industries.
Introduction of the rotary lime kiln process
Qualified limestone is stored in the silo, lifted by the elevator and transported into the top silo of the preheater. In the silo on the top of the preheater, the feeding amount is controlled by the upper and lower level gauges, and then the limestone is evenly distributed into each chamber of the preheater through the feeding pipe.
Limestone is heated to about 900°C by 1150°C kiln flue gas in the preheater, and about 30% of it is decomposed. It is pushed into the rotary kiln by a hydraulic push rod, and the limestone is sintered and decomposed into CaO and CO2 in the rotary kiln. The lime generated after decomposition enters the cooler, and is cooled to below 100°C by the blown cold air in the cooler and discharged. The heat-exchanged 600°C hot air enters the kiln and combusts with gas. The exhaust gas is mixed with cold air again, enters the bag filter through the induced draft fan, and then enters the chimney through the exhaust fan.
The lime coming out of the cooler is sent to the finished lime warehouse through vibrating feeder, chain bucket conveyor, bucket elevator and belt conveyor.
Structural features of rotary lime kiln
1. Calcination method: countercurrent calcination
2. The vertical preheater with low pressure loss can effectively improve the preheating effect, and the decomposition rate of the preheated limestone entering the kiln can reach 30%.
3. The reliable combined scale seal is used to make the air leakage coefficient less than 10%, and the composite refractory material is used to reduce the radiation heat loss.
4. Adopt the square vertical cooler with filling type and partition ventilation, so that the temperature of the lime out of the cooler is at an ambient temperature of 65 degrees Celsius, which is convenient for transportation and storage, and can preheat the secondary air entering the kiln to above 700 degrees Celsius. Contributes to the complete combustion of fuel.
5. The lime rotary kiln system adopts micro-negative pressure operation, and the production environment is clean and environmentally friendly.
Precautions for using lime rotary kiln
1. Before using the lime rotary kiln, you should understand the properties of the lime, so as to ensure the best use of the material, and finally ensure the normal operation of our lime kiln equipment.
2. During the use of the lime rotary kiln, pay attention to the working status of the lime kiln, and see if there is any abnormal noise in the lime kiln to judge whether the equipment is working well or not.
3. After the lime rotary kiln is used, it must be cleaned to facilitate normal use in the next use.
Technical characteristics of roraty lime kiln
- Production capacity: Our company provides the design and manufacture of 200t/d-1200t/d rotary kiln. The production capacity can be adjusted within a certain range to achieve stable operation without affecting quality and consumption indicators.
- Limestone particle size: 20-40mm
- Fuel type: The kiln can use natural gas, coke oven gas, calcium carbide furnace tail gas, coal powder, etc. as fuel.
- Lime products: The quality of lime is good, the residual CO2 is not higher than 1.5%, and the activity is 360ml (up to 400ml, 4N HCL method for ten minutes).
- Heat consumption: low heat consumption, about 1200kcal/kg lime.
- High operating rate: it can operate continuously for 48 weeks per year.
- High degree of automation, realize one-button automatic production.
Comparison between rotary lime kiln and Annular Shaft Lime Kilns
From the perspective of raw material usage, the annular shaft lime kiln and the rotary kiln are complementary. In the limestone mining process, among the qualified limestone blocks after crushing, about 50% of the particle size is 40-80mm, and about 20% of the 20-40mm , 20-10mm accounted for about 20%, 10% below 10mm.
At present, mine resources are becoming more and more tense, and we must reasonably match the lime kiln type in order to improve the comprehensive utilization rate of limestone resources and fully extend the life of the mine. In this way, on the one hand, limestone resources are fully utilized, and on the other hand, the purchase cost of limestone is also reduced.
In terms of fuel usage, the annular shaft lime kiln and rotary kiln have mutual advantages. The annular shaft lime kiln can directly use converter gas, a low calorific value fuel produced in steelmaking. However, the rotary kiln must use high calorific value fuels, such as coke oven gas, mixed gas or natural gas. The advantage of the rotary kiln is that it can directly use pulverized coal as fuel, and has wider adaptability to fuel.
Specification Of Rotary Lime Kiln
| Capacity （t/d） | 150 | 200 | 250 | 300 | 350 | 400 | 500 | 600 | 750 | 800 | 1000 | |
| Product | Active lime, Calcined dolomite | Active lime, Calcined dolomite | Active lime, Calcined dolomite | Active lime, Calcined dolomite | Active lime, Calcined dolomite | Active lime, Calcined dolomite | Active lime, Calcined dolomite | Active lime, Calcined dolomite | Active lime, Calcined dolomite | Active lime, Calcined dolomite | Active lime, Calcined dolomite | |
| Preheater | Circular vertical preheater or polygonal vertical preheater | Circular vertical preheater or polygonal vertical preheater | Circular vertical preheater or polygonal vertical preheater | Circular vertical preheater or polygonal vertical preheater | Circular vertical preheater or polygonal vertical preheater | Circular vertical preheater or polygonal vertical preheater | Circular vertical preheater or polygonal vertical preheater | Circular vertical preheater or polygonal vertical preheater | polygonal vertical preheater | polygonal vertical preheater | polygonal vertical preheater | |
| Rotary kiln | size（m） | Φ2.5×40 | Φ2.8×42 | Φ3×46 | Φ3.2×50 | Φ3.5×54 | Φ3.6×56 | Φ3.8×58 | Φ4×60/Φ4.2×50 | Φ4.3×58 | Φ4.3×64 | Φ4.8×68 |
| Effective volume （m3） | 142 | 190 | 235 | 292 | 390 | 430 | 505 | 575/548 | 670 | 738 | 1005 | |
| Temperature （℃） | 1350/1250 | 1350/1250 | 1350/1250 | 1350/1250 | 1350 | 1350 | 1350 | 1350 | 1350 | 1350 | 1350 | |
| Cooler | Square vertical cooler | Square vertical cooler | Square vertical cooler | Square vertical cooler | Square vertical cooler | Square vertical cooler | Square vertical cooler | Square vertical cooler | Square vertical cooler | Square vertical cooler | Square vertical cooler | |
| Fuel | Gas, pulverized coal | Gas, pulverized coal | Gas, pulverized coal | Gas, pulverized coal | Gas, pulverized coal | Gas, pulverized coal | Gas, pulverized coal | Gas, pulverized coal | Gas, pulverized coal | Gas, pulverized coal | Gas, pulverized coal | |
| Heat rate（KJ/KgC3O） | 5300/5000 | 5300/5000 | 5300/5000 | 5300/5000 | 5225 | 5225 | 5100 | 5100 | 4810 | 4810 | 481 | |
Equipment List Of Lime Calcination Plant
| Capacity （t/d） | 150 | 200 | 250 | 300 | 350 | 400 | 500 | 600 | 750 | 800 | 1000 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Finished Product | Active lime, Calcined dolomite | Active lime, Calcined dolomite | Active lime, Calcined dolomite | Active lime, Calcined dolomite | Active lime, Calcined dolomite | Active lime, Calcined dolomite | Active lime, Calcined dolomite | Active lime, Calcined dolomite | Active lime, Calcined dolomite | Active lime, Calcined dolomite | Active lime, Calcined dolomite |
| Preheater | Circular vertical preheater or polygonal vertical preheater | Circular vertical preheater or polygonal vertical preheater | Circular vertical preheater or polygonal vertical preheater | Circular vertical preheater or polygonal vertical preheater | Circular vertical preheater or polygonal vertical preheater | Circular vertical preheater or polygonal vertical preheater | Circular vertical preheater or polygonal vertical preheater | Circular vertical preheater or polygonal vertical preheater | polygonal vertical preheater | polygonal vertical preheater | polygonal vertical preheater |
| Rotary kiln size (m) | Φ2.5×40 | Φ2.8×42 | Φ3×46 | Φ3.2×50 | Φ3.5×54 | Φ3.6×56 | Φ3.8×58 | Φ4×60/Φ4.2×50 | Φ4.3×58 | Φ4.3×64 | Φ4.8×68 |
| Effective volume （m3） | 142 | 190 | 235 | 292 | 390 | 430 | 505 | 575/548 | 670 | 738 | 1005 |
| Temperature （℃） | 1350/1250 | 1350/1250 | 1350/1250 | 1350/1250 | 1350 | 1350 | 1350 | 1350 | 1350 | 1350 | 1350 |
| Cooler | Square vertical cooler | Square vertical cooler | Square vertical cooler | Square vertical cooler | Square vertical cooler | Square vertical cooler | Square vertical cooler | Square vertical cooler | Square vertical cooler | Square vertical cooler | Square vertical cooler |
| Fuel | Gas, pulverized coal | Gas, pulverized coal | Gas, pulverized coal | Gas, pulverized coal | Gas, pulverized coal | Gas, pulverized coal | Gas, pulverized coal | Gas, pulverized coal | Gas, pulverized coal | Gas, pulverized coal | Gas, pulverized coal |
| Heat rate（KJ/KgC3O） | 5300/5000 | 5300/5000 | 5300/5000 | 5300/5000 | 5225 | 5225 | 5100 | 5100 | 4810 | 4810 | 4810 |
Note1: Different customers, different customized solutions, and different equipment configurations.
Note2: we just list main equipment in calcination section, other equipment will listed on complete solution.
