Cement Sector
In cement factories each production phase is nearly always carried out by a single machine. Therefore, the breakdown of one of those machines as a consequence of the failure of one of the components can have substantial financial consequences over a long period of time.
The electric motors that drive the blowers, mills, grinders, crushers and furnaces are especially at risk if volatile dust penetrates the air filters and blocks the ventilation slots of the stator winding, eventually causing the breakdown of the operating machine.
- CRUSHING OF RAW MATERIAL
- The raw material obtained in the quarry is crushed by different electric motor-driven machines: jaw crushers, cone crushers, hammer crushers or impact crushers.
- PRE-HOMOGENISATION
-
The different components, i.e. clay, limestone or others, are mixed to make the different types of cement.
Throughout the entire process the raw material is distributed by conveyer belts that at times cover distances of up to several kilometres, driven by motors of up to 200 kW. - DRYING OF THE RAW MATERIAL AND PULVERISATION
- The raw material, which tends to contain a lot of moisture, is dried before or during the pulverisation process. In larger production plants vertical roller or cylinder mills are used for the pulverisation process and in smaller plants horizontal tube mills.
- HOMOGENISATION
- The cement meal is uniformly mixed through the action of air currents inside the silos.
- TREATMENT OF THE BURNED PRODUCT
- Before transporting it to the rotary tube kiln, the raw meal is heated in a cyclone exchanger of various phases, until reaching about 800ºC.
- BURNING
-
The meal from the preheater is fed to the rotary kiln. Due to the rotation of the kiln, which is inclined, it travels through the different reaction zones towards the outlet of the kiln and from there on to the cooler. The disintegration of the raw material takes place in the calcination zone, at temperatures of between 1050ºC and 1150ºC. In the sintering zone, with temperatures of between 1250ºC and 1450ºC, a reaction takes place between the clay, limestone and sand. That leads to a partial fusion and the formation of black-grey, granular cement clinker.
The rotary tube kiln is placed on bearing races which divert the load to the foundations through track rollers. The rotary tube kiln is driven by two electric motors through two pinion gears which engage with a gear ring. - CEMENT GRINDING
-
The clinker passes through the cooler, which it leaves at a temperature of 120-200ºC. Later it is distributed in doses and put in the silos.
The grinding process takes place in tube mills that contain metal balls which pulverise the clinker through impact and friction.
It is then sent on to the silos for its subsequent loading and distribution in doses to be packed and dispatched.
In this industry online predictive maintenance is key to:
Predicting faults in the main electric motors of the plant, those of the horizontal and vertical mills, those of the rotary kiln and those of the blowers.
Predicting faults in the main electric motors of the plant, those of the horizontal and vertical mills, those of the rotary kiln and those of the blowers.