Induced Draught Fans And Forced Draught Fans In Cement Factories

Cement factories heavily use draught fans in their boilers during the combustion process. The draft fans or draught fans as they are variously called in different countries and regions, play a critical role in the cement manufacturing process.

These fans also play a very important role in another major industry i.e. in thermal power plants where they facilitate different operations related to power generation. In thermal plants operated by coal, several types of process fans are used. So it is no surprise that draught fans are also used in cement factories as they need robust process fans for handling the manufacturing process.

In the cement industry, draught fans are extensively used to mechanically facilitate the requirement of air in the furnace. This helps in carrying out the combustion process in the right way. In cement factories, the two main types of draught fans used include induced draught and forced draught fans.

What is the function of draught fans in cement factories?
Draught fans are used in the cement manufacturing process to maintain a steady flow of air. There are two key types of draught fans. These are forced draft and induced draft fans. A forced draught fan compels the outside air to get into the furnace system. On the other hand, an induced draught fan takes flue gases from the furnace to the outer environment.

Both these types of fans are set to operate in perfect sync to balance the air system. This enhances the efficiency of combustion in cement factories.

Some of the functions of draught fans include supplying air mixture and pulverized coal for combustion, heating the system, regulating the combustion, and heating the air. On the other hand, they reduce the contaminants and toxic gases around the boiler by drawing them outside through the chimney.

Forced draught fans
The key function of forced draught fans is to ensure adequate air supply to the rotatory kiln/furnace in cement factories. These fans mechanically create air pressure in the combustion chamber. Unless the forced draught fan operating, the pre-heating and calcination process would not happen properly. When the heat from the furnace/rotatory kiln reaches the raw material the high temperature and heat cause chemical changes in the finely powdered raw material causing it to form clinkers. These clinkers are ground later to produce cement. The forced draught fans play a key role in furnace combustion and also in ensuring the raw material is exposed to high temperatures.

Induced draught fans
Induced draught fans are necessary to create negative or suction energy in the furnace/rotary kiln in cement factories. This helps in removing flue gases from the furnace area. So, after the combustion process, these gases find a vacuum created by induced fans and flow out. In this process, they come in contact with the raw materials and cause a change in the chemical composition due to the heat from the furnace. The function of induced draught fans is to suck the air out of the kiln. Usually, a chimney is used to discharge these gases from the kiln.

Induced draught fans regulate the pressure in the furnace/rotary kiln. This helps the combustion process to take place effectively and it eliminates the flue gases.

Why are both the induced and forced draught fans needed?
Forced draught fans are needed to ensure proper combustion in the cement manufacturing plant. This helps in maintaining the right operational environment, leading to increased productivity. In terms of power, induced fans need more electricity to operate compared to forced draught fans. Incorporating both these types of fans in cement factories, it’s possible to boost productivity.