Description

Wet rotary kiln, as building material equipment, is widely used in metallurgy, chemical industry, building refractory material, environmental protection and other industries. The rotary kiln consist cylinder, supporting device, support device with retainer wheel, drive device, active kiln head, kiln end sealing device, coal injection pipe device and other components. Wet rotary kiln body shows a certain degree of tilt to horizontal level. The entire kiln body is supported by roller device. It also has retainer wheel device to control the kiln body in case it runs up and down. The drive system also has auxiliary drive that can make kiln body drive when major power is off and prevent kiln body bending and being out of shape besides major drive. Kiln head and kiln end sealing device uses advanced technology to ensure reliability of sealing.

Characteristics

Raw material is made into mud. So it can adapt to non-homogeneous material. Raw material composition is uniform and its process is stable. Firing clinker quality is high and clinker intensity level is high. During the process of grinding, dust is less and kiln end flying ash is less. But in the wet production, 30%-40% slurry of water is evaporated and huge heat is consumed. Energy consumption accounts for 1/2～1/3 of cement cost. Compared with vertical kiln and dry rotary kiln, it is very high. Our country has listed wet cement production as restricted because of high heat consumption, high energy consumption and high water consumption.

Basic functions

Wet rotary kiln should have the following basic functions in order to calcinate good cement clinker and reduce coal consumption.
1. Inject pulverized coal to kiln with the dispersed shape and a certain speed. Try to strengthen coal and air mixing.
2. Strengthen air disturbance and increase air diffusion speed in order to blow away Volatile gas membrane around pulverized coal particle and enlarge the contact of fixed carbon and secondary air.
3. Add right amount of fresh air and solve the problem of hypoxia in the flame center.
4. Low primary air consumption and improve the heat recovery efficiency of clinker.
5. Adapt to feeding material change, flame shape and length quickly. It should be easy to control and adjust the position of flame.
6. Strong adaptability toward combustion quality.
7. Wet rotary kiln environmental temperature is very high and rotary kiln nozzle has high temperature resistance. Effective high temperature resistance measures should be done to prevent nozzle from being burned.

Composition

1. Cylinder and kiln lining: Cylinder, rolled by steel plate, is the container for the completion of physical and chemical changes. So it is the body of rotary kiln. Kiln material temperature is up to 1450℃, so cylinder body has masonry refractory material to protect cylinder and reduce heat dissipation. According to the process of material change, cylinder is divided into various working zones, such as drying zone, preheating zone, decomposition zone, firing zone and cooling zone.
2. Heat exchanger: To enhance the effect of heat transfer, the cylinder body often also has a variety of types of chain to make up heat exchange devices.
3. Wheel belt: cylinder, kiln lining, material and all rotary kiln weight comes to support device through wheel belt.
4. Support device: It consist a pair of roller bearings and a big base plate. A pair of roller supports a wheel belt to allow cylinder to move freely and convey huge load to the basic. Support device has generally 2-7 blocks. It is equipped with retainer wheel on a certain block or several blocks, which is called support device with retainer wheel. Its role is to limit or control the rotary kiln section of axial movement.
5. Drive device: gear ring is equipped in the middle cylinder and fixed in the cylinder by spring plate. It drives through gear wheel to make cylinder rotate. At the same time, in order to adapt to operation and maintenance needs, large rotary kiln is equipped with auxiliary drive to make kiln drive with a very low speed.
6. Kiln hood: it is intermediate which connects kiln head and middle process equipment and it is the zone for looking at the operation of fire. Therefore kiln hood is equipped with fire hole and access door.
7. Burner: Rotary burner injects through cylinder rotary head and heat material by frame radiation to the desired temperature. Burner consist coal burner, gun oil, gas nozzle and so on.
8. Cold smoke chamber: it is intermediate of connecting kiln end and material feeding equipment. Smoke comes into smoke flue and dust collecting system through cool smoke chamber. Feed material directly to kiln end from feeding device.
9. Feeding device: it is accessory equipment for rotary kiln. Feeding should be stable, uniform and easy to control so that it can cooperate with the operation of kiln.

Technical