Technical requirements for the installation of rotary kilns in cement production 5

<> rotary kiln is the main equipment used for cement clinker calcination in cement plants. Its main structure is composed of kiln cylinder, supporting device, kiln head and kiln tail sealing device, transmission device, feeding and calcination device, which is the most critical equipment in the cement production process.

The rotary kiln with 5000t D kiln external decomposition furnace is selected for this project.

1. Technical performance.

Specifications of the kiln: inner diameter, total length 72m;

Slope of the kiln (sin):

Speed: main drive, auxiliary drive;

Number of supports (carrier wheel set): 3;

Required power: main drive power 630kw, auxiliary drive 75kw;

Number of retaining wheels: two hydraulic retaining wheels, distributed at 2-3 supports;

Production scale: 5000t d clinker;

Total weight of kiln body:

2. Working principle.

The cylinder of the rotary kiln is made of steel plate, the cylinder is inlaid with a refractory lining, and the horizontal line is at a specified inclination, supported by 3 wheel belts on each gear support device, and a large gear ring is fixed with a tangential spring steel plate on the span inner cylinder near the wheel belt at the feeding end, and there is a pinion meshed with it under it. During normal operation, the main drive motor transmits power to the open gear device through the main reducer to drive the rotary kiln. The material enters the kiln from the kiln tail for calcination.

Due to the tilting and slow rotation of the cylinder, the material both rolls in the circumferential direction and moves along the axial direction, continuing to complete the process of decomposition and firing, and finally, the raw material enters the cooler for cooling through the kiln hood.

1. The wear of parts should be small, and the use of Zhou Dynasty should be long, because the airflow temperature at the sealing place of the kiln is high, there is a lot of dust, and lubrication is difficult and easy to wear. In the shape of the celery design, to avoid the place of dust, in the material requirements to be able to withstand high temperature, wear, to prevent the leakage of lubricating sleeves.

2. One of the key is that the sealing performance should be good, the negative pressure at the kiln head is small, and the sealing requirements can be lower near the zero pressure. However, the negative pressure at the end of the kiln is high, and the dry preheater kiln can reach 150-l000pa, and the wet long kiln can reach 300-1500pa, so the sealing device is required to adapt to such negative pressure.

3. On the premise of ensuring reliable sealing, it is well adapted to the normal operation of the cylinder and the normal kiln up and down channeling, radial runout, bending of the center line of the cylinder and manufacturing error, thermal expansion and contraction when the temperature of the kiln body changes, and slight bending and deformation of the cantilever end. The structure is simple, easy to manufacture, can work reliably during the long staring period, and is easy to maintain.

Once the kiln head enters the excessive cold air, it is possible to reduce the amount of secondary air entering the kiln by the clinker cooling equipment, and reduce the temperature of the secondary air, which is not conducive to the cooling of the kiln, and the flame temperature in the kiln will also be reduced, thereby affecting the combustion rate of the fuel and increasing the heat loss. If the kiln tail leaks, due to the large negative pressure, it is easy to absorb a large amount of cold air, so that a large amount of exhaust gas in the kiln can not be discharged, and the fuel can not be completely combusted, resulting in the destruction of the thermal system, increasing the fuel consumption and exhaust fan load, and increasing the power consumption, reducing the production and quality of the kiln and affecting the safety and efficiency of electric dust collection. The performance of the sealing device is of great significance to the normal operation of the cement rotary kiln system and the quality and energy consumption of the kiln.

Yuding Machinery specializes in the production of cement rotary kiln manufacturers, cement rotary kiln working principle:

The cement rotary kiln runs slowly under heavy load alternation at high temperature, and the level of maintenance of its accessory equipment and thermal system control is related to the safety and efficiency of the rotary kiln operation. The maintenance of the transmission device focuses on the lubrication, operation status, dynamic detection and meshing accuracy of the large and small gears of the equipment; The installation accuracy of the supporting device determines whether the rotary kiln can operate safely and reliably, and attention should be paid to the reasonable control of the distribution of the bearing capacity of each gear supporting roller, the arrangement of the supporting roller, the upward and downward pressure and time of the hydraulic retaining wheel, the force of the supporting roller, and the gap between the wheel belt and the backing plate. The quality of the sealing device directly affects the thermal system and operating cost of the rotary kiln.

Strengthen the daily maintenance data collation and analysis of rotary kiln, which is conducive to the management of equipment.

The working principle of cement rotary kiln is as follows:

Semi-dry technology is the production technology of discharging raw material such as rotary kiln after adding water to make dry powder raw material into balls, and the main representative product is Libo kiln, whose casing is immovable, welded with steel plate, and inlaid with refractory bricks. Inside the casing is a rotating grate, from which a horizontal plane is formed, which moves slowly at an average speed. The upper part of the grate is worked, and above it there is a ball disc that continuously supplies 5-25mm diameter balls with a moisture content of 12-14%.

The inner chamber of the furnace is divided into two chambers by transverse partitions. An exhaust fan is used to create negative pressure in the lower part of the chamber, and a set of cyclone dust collectors is installed in the kilometer of the first exhaust fan.

Because there are three heat transfer modes between gas-solid and solid-solid in the kiln at the same time: radiation, convection and conduction. The relationship was complicated. In addition, in the rotary kiln system, the preheater and cooler are connected to the end of the kiln, which will also have a certain impact on the gas-solid temperature distribution in the kiln to a certain extent.

As well as the rotary kiln as a conveying equipment, the law of material movement, dust flying circulation, etc. also have an impact on heat transfer, which increases the design and manufacturing difficulty of semi-dry rotary kiln.

Due to the backwardness of the wet rotary kiln process, the state has banned the use:

Because the raw meal is made into slurry, it has strong adaptability to heterogeneous raw materials, uniform raw meal composition, stable process, high quality of fired clinker, high clinker strength grade, less dust in the grinding process, and less fly ash at the kiln tail. However, the evaporation of 30% and 40% of the slurry moisture during wet production requires a large amount of heat, and the energy consumption accounts for 1 2 1 3 of the cement cost, which is higher than that of vertical kiln and dry rotary kiln. Due to the high heat consumption, large energy consumption, large water consumption and water consumption during production, wet cement production has been listed as a restricted kiln type in China.

The installation steps of the rotary kiln are as follows: 1. Base installation: 1

The base is mounted on the foundation pier; (1) Draw a longitudinal and transverse center line on the base; (2) The placement position of the base: its longitudinal and transverse neutral line should coincide with the center plate. 2.

Use a slope gauge to correct the inclination. Second, the installation of the supporting wheel group: clean the parts, according to the matching code and number for assembly 1

Check the fit of the carrier journal with the plain bearing pads. (1) The contact angle between the bearing and the journal is not less than 90°; The contact point is 2-3 cm2; (2) The side clearance is the diameter of the roller journal). (3) The contact point between the spherical tile back and the spherical surface of the bearing seat is 1-2 cm2.

If the above requirements cannot be met, it is necessary to re-grind. 2.The supporting wheel group is hoisted on the base as a whole and aligned (1) the center position is aligned

The alignment of the center position of the carrier set should be aligned with the longitudinal and transverse centerline of the base with the longitudinal and transverse centerline of the foundation. The distance between the longitudinal centerline of the two supporting wheels in the supporting wheel group and the longitudinal centerline of the base should be equal, and its error shall not exceed; The transverse centerline of the supporting roller should coincide with the transverse centerline of the base, and its error shall not exceed, and the axial clearance c at both ends of the supporting roller is equal. (2) Elevation and inclination measurementElevation and inclination measurement are divided into preliminary measurement and accurate measurement.

During the preliminary measurement, if the division is hoisted, measure the elevation and inclination of the center point of the top surface of the base, and if the whole is hoisted, measure the elevation slope of the center of the top surface of the supporting wheel group. For accurate measurement, it is also to measure the elevation and inclination of the center of the top surface of the carrier wheel set. The elevation of the center of the top surface of the supporting roller cannot be obtained directly on the drawing.

3.The total inspection of each wheel stopper: When the installation of each stop wheel is completed, the general inspection should be carried out (1) the total inspection of the center position

According to the kiln head, the center eye of the kiln tail center plate is the benchmark, and the center position of each supporting wheel group is checked with a theodolite or laser straightener, and the error shall not be exceeded. Based on the transverse centerline of the supporting wheel group of the transmission foundation, the oblique center spacing size of the two adjacent supporting wheel groups is measured, and the error shall not exceed 3mm. Then measure the oblique center spacing size of the kiln head and kiln tail two supporting wheel groups, and its error shall not exceed the elevation and the total slope inspection

It is mainly to measure the relative slope elevation of the adjacent two supporting wheel groups, and its error shall not be exceeded. Then measure the relative slope elevation of the two supporting wheel groups at the head and tail of the kiln, and its error shall not exceed 2mm. (3) The inspection of inclination is carried out at the same time as the elevation inspection and the levelness inspection of the supporting roller.

Cement rotary kiln.

Cement rotary kiln is the main equipment for calcining cement raw meal into cement clinker, which forms cement clinker through several main stages of dehydration, drying, preheating, decomposition, firing and cooling.

At present, there are two main types of cement kilns, one is the kiln cylinder horizontal (with a slight inclination), and can be used for rotary movement called rotary kiln (also known as rotary kiln); Another type of kiln cylinder is vertically not rotating, which is called vertical kiln.

1. Types of wet rotary kilns: The cement kiln used in wet production is called wet kiln, and wet production is to make raw meal into a slurry with a water content of 32% and 40%. Because it is prepared into a slurry with fluidity, the raw materials are mixed well, and the composition of the raw meal is uniform, so that the quality of the fired clinker is high, which is the main advantage of wet production.

2. Types of dry rotary kilns:

Compared with wet rotary kilns, the advantages and disadvantages of dry rotary kilns are opposite. The dry process makes the raw meal into a dry raw meal, and the moisture is generally less than 1%, so it reduces the amount of heat required to evaporate the water than the wet process. Due to the high temperature of the exhaust gas, the heat consumption of the hollow kiln is not low.

Dry production makes raw meal into dry powder, which has less fluidity than slurry. So the raw materials are not mixed well, and the ingredients are not uniform. Cement rotary kiln is mainly used for calcining cement clinker, which is divided into two categories: dry production of cement rotary kiln and wet production of cement rotary kiln.

metallurgical chemical rotary kiln is mainly used in metallurgical industry, iron and steel plant, poor iron ore magnetization roasting; chromium and nickelite oxidation roasting; refractory plant roasting high-alumina vanadium earth ore and aluminum plant roasting clinker, aluminum hydroxide; Chemical plants roast minerals such as chrome ore and chrome ore powder. Lime rotary kiln (i.e. activated lime rotary kiln) is used for roasting active lime and lightly burned dolomite for iron and steel plants and ferroalloy plants.

Cement rotary kiln is the main equipment of cement clinker dry and wet production line. Cement rotary kilns are widely used in metallurgy, chemical industry, building refractories, environmental protection and other industries. The cement rotary kiln is composed of a cylinder, a supporting device, a supporting device with a retaining wheel, a transmission device, a movable kiln head, a kiln tail sealing device, a coal injection pipe device and other components.

The kiln body of cement rotary kiln is inclined to a certain extent with the level, the whole kiln body is supported by the supporting roller device, and there is the retaining wheel device that controls the kiln body to move up and down, the transmission system is not only provided with the main drive, but also sets up the auxiliary transmission device that can still make the kiln body rotate when the source is broken in the main power supply, and prevents the kiln body from bending and deforming, and the sealing device of the kiln head and kiln tail adopts advanced technology to ensure the reliability of the seal. In addition, in terms of environmental protection, the use of cement rotary kiln to incinerate hazardous waste, garbage, which not only makes full use of waste but also helps environmental protection.

In addition to calcining cement clinker, cement rotary kiln is also used to calcinate clay, limestone and slag drying; In the production of refractory materials, cement rotary kilns are used to calcinate raw materials to make them stable in size and increase in strength, and then reprocess and form.

The main difference in structure is that the length-diameter ratio of the new dry rotary kiln L d 16 is a short kiln, and the two-fulcrum (two-gear kiln) rotary kiln with a L D ratio of less than 13 is the current ultra-short kiln and two-gear support kiln, and the wet rotary kiln is generally a long kiln L d = 30-42 is a long kiln.

The kiln length of the new ultra-short kiln can be shortened by more than 20% compared with the conventional pre-decomposition kiln, which not only greatly improves the process-related factors, but also has outstanding advantages in terms of machinery. After the three-gear support is changed to a two-gear support, the structure changes from a static indefinite system to a static system. In this way, no matter the foundation sinks, or the kiln cylinder is deformed and bent, it will not cause the overload of the cylinder, the supporting roller, the wheel belt and the transmission mechanism, and will not cause the uneven contact between the supporting roller and the wheel belt, and the uneven force of the supporting rollers on each gear and each supporting side.

In order to avoid the occurrence of mechanical accidents such as cylinder fracture, broken shaft of supporting wheel, overheating of bearing and burning tile, excessive and uneven wear of supporting roller and wheel belt, burning of transmission motor and abnormal damage of main reducer, etc., the reliability and operation rate of the kiln system are greatly improved.