Advantages of rotary kiln in calcining active lime production line
1. Rotary kiln has a high output and is very suitable for large-scale active lime production line. Now there are 2200 tons of lime rotary kiln in the world, and many 150-300 tons of lime rotary kilns have been built at home and abroad, which run well and are also suitable for the application of small and medium-sized lime enterprises.
2. Rotary kiln belongs to open type calcination. The kiln body is simple, the air flow is smooth, the sulfur-containing flue gas can be discharged in time, and the sulfur in fuel is not easy to adhere to, so the sulfur content of products is low, which meets the requirements of steel-making. At the same time, the material rolling forward uniformly in the kiln, heating uniformly, product quality is stable, raw and over-burning rate is very low, and it can calcine high activity of steel-making lime. Under the same conditions, the activity of lime produced by rotary kiln is higher than that produced by gas kiln, with an average of over 30 ml. The activity of lime produced by rotary kiln is generally 340-380 ml, or even up to 400 ml.
3. Rotary kiln can directly calcine 10-50mm fine-grained limestone. Ordinary mine products 0-30mm fine-grained limestone accounts for about 30-40% of the total output. This part of limestone can not be used in other kilns. With the concentrating of iron and steel raw materials, quicklime is gradually replaced by limestone in sintering, and fine limestone can not be comprehensively utilized. The construction of rotary kiln production line can not only make full use of high quality limestone mine resources, but also conform to the sustainable development policy of lime industry.
4. The vertical preheater installed at the end of the kiln can make full use of the high temperature flue gas produced by calcination in the rotary kiln, and preheat the limestone from room temperature to initial decomposition state. This can not only greatly increase the output of rotary kiln, but also fully reduce the heat consumption per unit product.
5. The vertical cooler at the kiln head can not only make the high-temperature lime quench, improve the product activity, but also change into transportation and storage. At the same time, the secondary air entering kiln at higher temperature can be obtained. It can effectively increase the firing temperature in the kiln and reduce fuel consumption.
6. The flue gas temperature discharged by the vertical preheater at the kiln tail is low, between 280-350 C, and the dust content is low, which is about 20g/Nm3. This makes the configuration of the follow-up flue gas treatment simple and effective, and meets the requirements of environmental protection.
7. Stability of lime quality in rotary kiln is its greatest advantage. Activated lime production equipment adapts to the comprehensive development of mine resources and has a good development prospect.
Activated lime is widely used in steel, alumina, magnesium, calcium carbide and power plant desulfurization and paper-making industry. Activated lime is an important auxiliary raw material for steel-making. The use of activated lime has a series of characteristics, such as improving the quality of steel, increasing production, reducing steel consumption and cost, and stabilizing operation. Practice has proved that all steel-making enterprises using active lime have achieved remarkable economic benefits. In recent years, the production of lime for steel-making in China has increased by 40%, but the high-grade lime with activity of more than 300 ml has increased from 27% to 29.5% of the total amount of steel-making lime, and only increased by 2.5%. Active lime rotary kiln of Jiangsu Pengfei Group has formed a series of 1000 tons per day products, which are exported to Vietnam, Russia, Central Africa, etc. on the basis of introducing and digesting advanced technology from abroad.
1. Steel-making practice proves that activated lime can improve desulfurization and dephosphorization efficiency by 80% and shorten smelting time. The reaction time of lime in vertical kiln is at least 6-10 minutes. In addition, the furnace ridge is increased by more than 40%. The consumption of burden has also been reduced by 5-8Kg/t steel, which saves about 15 million tons per year in terms of 10 million tons. The production benefit is remarkable.
2. The removal efficiency of S and P by activated lime is obviously improved. The average removal rate of S in steel-making is 34.5%, especially for high S hot metal (S < 0.06%). The consumption of desulfurizer can be reduced by about 45%.
3. When active lime is used in steel-making, iron consumption can be reduced by 5-15Kg/t steel, as well as molten steel splashing and viscous oxygen lance, furnace mouth sticking and flue gas sticking.
4. The unit consumption of lime decreases: the unit consumption of active lime for steel-making can be reduced by 20-25 Kg/t steel compared with that of inactive lime, while that of inactive lime is not less than 65-70 Kg for steel and 40-41.5 Kg/t for steel.
5. Activated lime steel-making slagging is fast, desulfurization and dephosphorization ability is remarkable, and production efficiency can be increased by 5%~10%.