Types of Kiln in Cement Industry

In the cement industry, kilns are crucial equipment that are used for heat treatment process of materials to produce cement. On the basis of their design and functioning, kilns in the cement industry can be categorized into various types.

1. Wet Kilns:

Wet kilns are those in which slurry materials are introduced and mixed with hot gases inside the kiln. This type of kiln is typically longer than the dry process kiln, and the wet process requires a higher amount of energy to operate. However, wet kilns are capable of producing high-quality clinker.

2. Dry Kilns:

Dry kilns are those where preheated raw materials pass through a preheater tower before entering the rotating kiln. Dry process kilns are comparatively smaller in size as compared to wet process kilns. Dry kilns are considered more energy-efficient than wet kilns as they require lower temperatures to produce clinker and use less fuel.

3. Preheater Kilns:

A preheater kiln, also known as a suspension preheating system, utilizes a preheater tower with cyclones to preheat raw meal before entering the kiln. The main objective of preheater kilns is to reduce the fuel consumption required to achieve high temperatures for clinker production. Because of their efficiency, preheater kilns are popular in the cement industry.

4. Precalciner Kilns:

Precalciner kilns are a type of preheater kiln in which additional heat is provided by a secondary combustion chamber known as the precalciner. In this chamber, fuel and air are preheated and mixed before being fed into the main kiln. Precalciner kilns have a higher thermal efficiency than other kiln types and can handle different types of fuels, including hazardous waste.

5. Long Dry Kilns:

Also known as Lepol kilns, long dry kilns have suspension preheaters and a precalciner system, similar to preheater kilns. However, they also include a preheating grate, with interconnecting ductwork between a series of cyclonic preheating chambers, to prevent the build-up of raw materials. Long dry kilns consume less energy, but they produce more dust and have lower production capacity when compared to other types of kilns.

Each type of kiln has its advantages and disadvantages, and cement manufacturers choose the kiln type that best suits their production needs, energy efficiency, and economic viability.