Research on rotary kiln lining equipment Henan Hongxing

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Research on lining equipment of rotary kiln

With the advantages of wide adaptability of raw materials, diversification of fuel, less consumption of heat-resistant alloy steel, uniform products, and more conducive to the large-scale blast furnace, the grate kiln annular cooler process has become a popular production process of oxidized pellets in China. In 2013, the chain return loop production line accounted for more than 60% of the oxidized pellet production lines in China. With the increasingly strict requirements of the national policy on "green ironmaking", high energy consumption, short service life of equipment and poor environmental protection level have become the prominent problems faced by the rapid development of China's chain recycling epoxidation pelletizing process. "Long life and energy saving" has become an important direction of its development.

 Rotary kiln

In this paper, the rotary kiln, one of the three main engines in the chain return loop production process, is taken as the research object. In order to prolong the service life of the rotary kiln, the kiln lining device is studied in depth, and a series of long-life, high operation rate, safe and reliable long-life rotary kiln devices for oxidized pellets are developed.

1. Masonry of composite kiln lining with multiple pouring materials

Kiln lining is the core equipment of rotary kiln. A set of good kiln lining structure scheme can make each precast brick achieve the performance of stress, expansion and wear resistance, so as to greatly extend the overall life of rotary kiln. At present, there are two kinds of brick masonry commonly used in pelletizing plant, which are full brick masonry and brick alternate masonry.

(1) All brick masonry

The kiln lining structure from the rotary kiln circumferential direction is n precast bricks (n is determined according to the kiln diameter) plus a castable belt, in which the prefabricated bricks constitute the main body of the kiln lining, and the castable is used to lock the mouth to fix the prefabricated bricks and absorb the error amount. It is difficult to ensure the masonry of this structure because of the high requirements for the processing accuracy of the prefabricated brick and the flatness of the inner surface of the kiln shell.

(2) Alternate brick masonry

The kiln lining structure is a prefabricated brick and a castable belt from the circumferential direction of the rotary kiln, which is constructed alternately. Because of too much castable belt, this structure is easy to cause uneven baking, which seriously affects the service life of kiln lining.

(3) Composite masonry with multiple castables

Through in-depth study on the shortcomings of the above two types of structures, the third type of multi castable belt composite kiln lining masonry is developed based on the improvement and optimization of the original structure.

This structure combines the advantages of full brick masonry structure and brick alternate masonry structure. From the circumferential direction of rotary kiln, it is a composite furnace lining structure with precast bricks as the main body and multiple (usually 4 ~ 8) castable strips uniformly distributed.

This structure is conducive to the close combination of the kiln body precast bricks. During the construction and installation, the requirements for the processing accuracy of the precast bricks are greatly reduced. At the same time, the number of pouring belts is relatively moderate, so the overall life of the kiln lining of the rotary kiln can be greatly extended.

2. Spraying self flowing thermal insulation layer

In the present, Rotary kiln The method of filling refractory fiber felt between precast brick and kiln shell is adopted for heat insulation. This method has some disadvantages, such as long construction period, poor heat insulation performance, fiber mat easily powdered in the production process, resulting in "red kiln" phenomenon. In view of the above shortcomings, a kind of spraying self flowing thermal insulation layer was developed, which used light spray coating or self flowing material instead of fiber felt. The structure is simple, the construction is convenient, the phenomenon of red kiln can be avoided, the heat insulation performance of rotary kiln can be improved, the kiln skin temperature can be reduced and the heat loss can be reduced. The construction steps are as follows:

(1) A section of precast brick is installed on the inner side of the rotary kiln along the circumferential direction (45 ° to 50 °);

(2) A sealing element is installed at the end of the prefabricated brick, and the sealing element is used to block the bottom of the prefabricated brick at the end to form a cavity so as to spray the indefinite light castable;

(3) The upper part of the prefabricated brick installed above is sprayed with (or flowed in) the unshaped light castable;

(4) After spraying, the sealing parts are removed after the natural drying and solidification, and the construction of the prefabricated brick insulation layer is completed;

(5) Repeat the above steps and construct section by section along the circumference of the rotary kiln until the construction of the whole kiln lining insulation layer is completed. The construction procedure diagram is shown in Fig. 5, and Fig. 6 is the photo of small test device.

Compared with the existing ones, it has the following advantages:

(1) The light material fills the lower space of the whole precast brick, and the gap between adjacent precast bricks cannot pass through the kiln shell, which avoids the phenomenon of "red kiln" caused by high temperature gas contacting the kiln shell through the brick joint in the production process.

(2) The compressive strength and shear strength of lightweight material are much higher than that of fiber felt. When the rotary kiln is rotating, the lightweight material can better withstand the rolling impact from prefabricated brick, and avoid the pulverization of insulation layer material.

(3) It can reduce the construction period of rotary kiln bricklaying and improve the construction safety factor.

Through the research, improvement and advantages summary of rotary kiln lining equipment, red star rotary kiln manufacturers have developed more efficient, longer service life and better safety performance of oxidized pellets Rotary kiln device Welcome to visit our factory to purchase new equipment.

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