The working principle and use of the rotary kiln in a cement plant
The working principle and use of the rotary kiln in a cement plant
On the one hand, the rotary kiln is a combustion device in which coal powder is burned to generate heat; on the other hand, it is a heat transfer device in which raw materials absorb the heat of gas for calcination. Fuel combustion, heat transfer and raw material movement must be reasonably coordinated to ensure that the heat generated by fuel combustion can be timely transferred to the raw materials through the rotary kiln during the time the raw materials pass through the rotary kiln, so as to achieve the goal of high production and low consumption.
The rotary kiln belongs to the category of building materials equipment and is a type of rotary kiln for lime. Rotary kilns can be divided into cement rotary kilns, metallurgical and chemical rotary kilns and lime rotary kilns according to the processed materials. The rotary kiln for cement production is the main equipment for dry and wet production lines. For the firing and feeding system of the rotary kiln for cement production, ignition is the key link for the rotary kiln to enter production, so sufficient preparation work should be done.
For the firing and feeding system equipment, including preheaters, there should be normal operation and adjustment of starting conditions. During the single-machine test run of the rotary kiln, attention should be paid to the specific conditions of the temperature and wear of the driving roller shaft, and the temperature of the bearing should not exceed 60 degrees.
In the past industrial production, there would often be a problem that the center line of the driving roller of the rotary kiln was not parallel to the center line of the kiln, which would cause the temperature of the driving roller shaft to rise too fast after the heat load test of the rotary kiln. Therefore, these should be paid high attention to and measures should be taken to solve them in time.
In the preheater of the rotary kiln, most of the inner linings of the refractory materials are castables, so a large amount of water is contained in the flue gas during the firing process. Therefore, the flue gas must be discharged through a bypass during the firing process of the rotary kiln, and is generally not passed through a bag filter.
The quality of the clinker is the core of the control of the burning system. The quality of the clinker directly affects the quality of the product and is related to the benefits of the enterprise. Therefore, it is necessary to pay close attention to the detailed parameters of the clinker quality and make dynamic observation and analysis adjustment to ensure that the clinker particles are uniform and compact and the cooling is good. The appearance color is gray and black, and the section has brightness, indicating stable quality and correct operation.
In addition to calcining cement clinker, rotary kilns are also used to calcine clay, limestone and ore, and for drying of minerals; in the production of refractory materials, rotary kilns are used to calcine raw materials, making their size stable and strength increased, and then processed into shapes. In the metallurgical and chemical industries, iron, aluminum, copper, zinc, tin, nickel, tungsten, chromium, vanadium and other metals are smelted in rotary kilns as smelting equipment for ores, concentrates and intermediates.