What is a coal mill

Coal mill is the most important machine in the coal industry. Basically, all industries that require a large amount of coal for the incineration process have coal mills. So what exactly is a coal mill? How many parts does it consist of? If you are not clear, it doesn’t matter, this article will answer you one by one. I believe that you will gain more knowledge about coal mills through this article.

A photo of a coal mill

What is a coal mill?

A photo of a coal mill

Coal mill, as the name implies, is a pulverizing machine that grinds raw coal into pulverized coal, and is the main equipment in the boiler pulverized coal preparation system. The reason why the coal is ground into powder and then incinerated is mainly to improve the combustion efficiency of the coal. After the coal is made into powder, the contact area between the coal and the air is increased, so that the coal can be fully burned and exert its full potential. greater utilization.

What is the main purpose of the coal mill?

A photo of a coal mill

This is the key equipment for crushing after the material is crushed. It is widely used in cement, silicate products, new building materials, refractory materials, fertilizers, ferrous and non-ferrous metal beneficiation, and glass ceramics. In addition to coal, dry or wet grinding of various ores and other grindable materials is also possible.

What types of coal mills are there?

A photo of a coal mill

Coal is mainly made into pulverized coal in the coal mill by three methods, namely crushing, crushing and grinding. This is the basis of coal grinding. No matter what type of coal mill, one or several methods will be selected Grinding coal. According to the classification of speed, coal mills can be divided into 3 types: low speed coal mills, medium speed coal mills and high speed coal mills.

Low-speed coal mill: It is mainly a drum type steel ball type, which is a rotating cylindrical drum or a drum with two conical ends. Steel balls are installed in the drum. It is a storage-type steel ball coal mill. The low speed has a wide range of adaptation to coal and reliable operation, especially suitable for grinding hard anthracite.

Medium speed coal mill: Medium speed is suitable for grinding medium hardness materials such as bituminous coal and lean coal, and can be widely used in electric power, metallurgy, building materials and chemical industries. The medium-speed coal mill has the advantages of compact structure, low metal consumption, small footprint, low initial investment, and low power consumption during operation.

High-speed coal mill: high-speed has two functions of a fan and a pulverizer. The raw coal is impacted by the impact plate and the volute, smashed into pulverized coal by friction, and then blown into the furnace by the fan. High-speed coal mill and pulverized coal separator can form a whole, with simple and compact structure, low initial investment, especially suitable for grinding bituminous coal.

The main parts of the coal mill?

The machine mainly consists of the following components:

A photo of a coal mill

Table base
The base of the platen mainly includes the gear box, the motor, the pull rod, the turning device, the anchor bolt box and the anchor bolt.

Electric motor
The motor is the core of the whole machine. Before starting the machine, check the rotation direction of the motor to ensure that it is not running in the opposite direction.

The coupling between the motor and the deceleration belt is used to drive the work. Before the machine is started, the rotation direction of the coupling should also be checked.

The reducer not only transmits the torque of the grinding disc, but also bears the impact force generated by the gravity of the grinding roller and the vibration of the machine, mainly including bevel gears, planetary gears, shafts and casings.

Machine base
The base is mainly composed of the base body, the slag discharge box, and the base sealing device. The lower part accommodates the gear box, and the upper part is equipped with the base sealing device.

Slag discharge box
The slag discharge box includes a hydraulic sliding slag drop door and a slag discharge box. The slag discharge box is equipped with a manual slag discharge door, and the slag discharge door is sealed with a silicate refractory fiber rope.

Base seal
The base sealing device consists of upper and lower connecting rings, upper and lower sealing rings, carbon sealing rings and springs.

Drive disc and scraper device
The transmission disc and the reducer are rigidly connected to transmit torque. At the same time, two scraper devices are symmetrically installed on the transmission disc, which rotate with the transmission disc.

Grinding ring and nozzle ring
The main working principle of the rotating spray resistance ring is to change the aerodynamic field at the nozzle, reduce the flow velocity of the nozzle, and double the service life of the nozzle ring.

Grinding roller
The roller grinding device consists of a roller frame, a roller shaft, a roller sleeve, a roller core, a bearing and an oil seal.

Pressing device
The pressing frame is an equilateral triangular structure on which a guide block is installed, and a hinge shaft seat is installed at the bottom of the pressing frame, which can be used to install the hinge shaft device.

Hinge device
The hinge shaft device is composed of a hinge shaft seat and a hinge shaft.

The casing is composed of the casing body, the anti-wear protection plate, the hot air outlet, the guide device, the tie rod seal, the maintenance door, various inspection doors, the casing sealing pipeline, and the fire-fighting gas pipeline.

Tie rod loading device
It consists of an upper pull rod, a pull down rod, a spherical self-aligning bearing, a measuring scale, a pull rod connecting ferrule, and a pin shaft.

Common faults and solutions of coal mills?

Three main types of common faults :

A photo of a coal mill

The machine vibrates greatly
The main reason may be that continuous work for a long time will cause continuous vibration, which may loosen the anchor screws, resulting in more and more vibration and increased noise; An extra nut is added to the anchor screw to reduce the chance of loosening.

Coal blocking
Coal blockage may be caused by too small air volume or failure to discharge residues in the furnace for a long time; the solution is to check whether the air volume is sufficient and adjust it to an appropriate air volume in time. Coal blockage occurs due to excessive residue in the furnace.

Insufficient machine output
Insufficient output may be caused by the mismatch between the coal input and the machine air volume, or the excessive wear of the grinding parts; the solution is to always pay attention to the ratio of coal input and air output, check the wear of parts, and meet the replacement requirements. To be replaced in time.

A photo of a coal mill

The above is the specific introduction about the coal mill and its parts. Do you still have any questions? If there is, you can leave a comment below. We will watch each of your comments carefully and answer your questions carefully. I hope you can continue to read other articles on our website.

Leave a Comment