Cement kiln is an essential cement equipment in the clinker production. There are two main types of cement kiln including a cement rotary kiln and shaft kiln. The rotary kiln is horizontal (with a little inclination) and does the rotary motion. The shaft kiln is vertical and fixed.
In the real cement manufacturing plant, cement rotary kiln has wider applications compared to shaft kiln. Why choose rotary cement kiln in a cement manufacturing plant? As a rotary kiln manufacturer, AGICO Cement offers rotary kiln and other related cement equipment, such as stacker and reclaimer, cement ball mill, vertical cement mill, cement crusher, suspension preheater, cement dryer, clinker cooler, cement roller press, etc. we also provide turnkey EPC project for cement manufacturing, including mobile crusher, cement grinding plant, cement manufacturing plant, etc.
Advantages of cement rotary kiln
- More options for fuel: Cement rotary kiln fuel has more options, such as solid fuel, gaseous fuel, liquid fuel, etc.;
- Performance advantages: Cement rotating kiln using low pressure drop vertical preheater, which can effectively improve the preheating effect, the pre-heated raw material into the kiln has a decomposition rate of 20-25%;
- Low cost: The cement rotary kiln not only requires less area, but also is conducive to energy saving and consumption reduction, and it has a good investment advantage;
- Environmental protection: The calcined tail gas is dedusted by a new-type dust collector to meet the national emission standards, and a bag filter is also used for dust removal at the vertical cooler blanking point.
Advantages in waste treatment
Compared with other methods, the cement rotary kiln has advantages in the treatment of hazardous waste or special incineration:
High processing temperature
The temperature of the material in the cement rotary kiln is between 1450 ° C and 1550 ° C, while the gas temperature is as high as 1700 ° C – 1800 ° C. At high temperatures, the toxic and harmful components in the waste is completely decomposed, and the general incineration removal rate reaches 99.99%. The temperature of the flue gas and materials in the incinerator can only reach 1200 °C-850 °C.
Long retention time
The cement rotary kiln is long and the waste lasts for a long time in the high-temperature state of the rotary kiln. According to general statistics, the total retention time of the material from the kiln tail to the kiln head is about 35min, the retention time of the gas above 950 °C is above 8s, and the retention time above 1300 °C is more than 3s, which is more beneficial to waste combustion and decomposition. The time for the flue gas higher than 1100 °C in the incinerator is only 2s.
Easy to stabilize burning state
The cement rotary kiln is a combustion system with large thermal inertia and stability. It consists of a metal cylinder, a refractory brick built in a kiln, and a crust formed in a firing zone and a material to be calcined. The mass is huge, and the refractory material has thermal insulation properties, and large temperature fluctuations cannot be caused by the amount and nature change of waste input. So the system is easy to stabilize and control.
Alkaline environment
The raw material composition used in the cement production determines the alkaline atmosphere in the rotary kiln, which can effectively suppress the emission of acidic substances, and fix the chemical constituents such as SO2 and Cl to reduce or avoid the generation of dioxins after general combustion.
No waste discharge
In the cement production line, only the raw materials and the clinker produced by the calcination process have no problems of slag generated by incineration of the general incinerator; and the cement rotary kiln operates under negative pressure, and the flue gas and dust rarely overflow.
Solidify heavy metal ions
By using the cement rotary kiln calcination process to treat hazardous waste, most of the heavy metal ions in the waste can be solidified in the clinker to prevent it from re-infiltrating and spreading the water and soil.
More incineration disposal sites and strong adaptability
The entire cement clinker plant has a number of high-temperature feed points that can apply for a variety of wastes of different natures and morphologies. In particular, when incineration of flammable hazardous waste in cement rotary kiln, the total emission of CO2 is reduced by half compared with the total use of coal, which has a great influence on environmental protection.
Characteristics of rotary kiln calcination
Rotary kiln belongs to cement equipment. The calcined clinker has stable size, high strength and easy processing. So it is popular in the cement manufacturing plant.
- The output of rotary kiln is high, very suitable for large-scale active lime production line; the vertical cooler at the kiln head can not only quench the high-temperature lime, improve the activity of the product, but also facilitate transportation and storage.
- The vertical preheater at the kiln tail can make full use of the high temperature flue gas generated by calcination in the rotary kiln, and preheat the limestone from the normal temperature to the initial decomposition temperature state. This not only greatly increases the output of the rotary kiln, but also reduces the heat consumption per unit of product;
- The rotary kiln can directly calcine 10~50mm fine-grained limestone, and the general limestone mining product 0~30mm fine-grained limestone accounts for 30-40% of the total output. This part of limestone can’t be used in other types of cement kiln.
- With the “fine materialization” of steel raw materials, sintering gradually replaces limestone with quick lime, and fine-grained limestone cannot be comprehensively utilized.
- The construction of the rotary kiln production line can not only make full use of high-quality limestone mine resources, but also meet the sustainable development policy of the lime industry.
Rotary kiln types
There are various types of rotary kiln in the cement industry. According to the raw material production process, the rotary kiln can be divided into the dry-process rotary kiln and wet-process rotary kiln.
Wet-process rotary kiln
The wet process refers that make raw materials into cement slurry contain 32%-40% water. The finished cement slurry is diffluent, so the raw materials have a good mixture, the raw material composition is uniform, so the clinker is high-quality.
Dry-process rotary kiln
The dry-process rotary kiln has opposite features. The dry process cement production line process raw materials into raw material powder and the moisture is less than 1%.
In conclusion, cement rotary kiln is very suitable for cement manufacturing. AGICO cement always provide high-quality cement rotary kiln with competitive price and one-stop service, welcome to contact if you have any need! we can offer professional suggestions about how to select a cost-effective cement kiln?
