Vertical Shaft Kiln – Core Functionality

The Vertical Shaft kiln, or simply vertical kiln, is a common piece of machinery used in cement plants of all sizes to preheat and calcine clinker. This machine can fully automate the feeding, calcining, crushing, and discharging procedures.

The Vertical Kiln was the first cement kiln developed and saw widespread use in cement factories worldwide before the rotary kiln was designed. Even now, vertical kilns are in high demand in many regions worldwide.

What a Vertical Shaft Kiln Is and How It Functions

It is standard practice for vertical kiln cement plants to first turn the ground raw materials into wet pellets by adding 12-14% water to the pelletizing pan of the disc pelletizer. After being calcined, the wet pellets are ejected from the kiln's bottom.

The interior of the Vertical kiln is segmented into three distinct areas, labeled from highest to lowest by their respective temperatures during operation: the preheating area, the calcining area, and the cooling area.

The Preheating Zone

When wet pellets are introduced into a kiln, the hot air circulating from the bottom to the top causes the water within the pellets to evaporate.

Meanwhile, the volatile components are constantly escaping as the fuel temperature increases. Since the heated air flow does not contain oxygen, the volatile material is expelled into the atmosphere and exhaust gas.

The material ball continues to sink deeper into the kiln supplied by Vertical shaft kiln Suppliers in India as its temperature rises due to the force of gravity. Dehydration of the kaolin occurs between 500 and 600 °C; further heating causes carbonate to dissolve, triggering a portion of the solid-state process.

The preheating zone's material height is 5-10% of the kiln body's total height, and its temperature range is 20-1000°C.

The Calcining Zone

The raw material's temperature remains over 1000 °C as it descends toward the calcining zone.

Most of the coal in the raw material begins to burn at this point, causing a rapid rise in temperature and a multitude of solid-state reactions; the exothermic solid-state reaction causes the temperature to soar to well above 1300 °C, at which point the material appears liquid and enters the sintering phase.

Coal quality, pellet size, air flow, raw material homogenization, discharge rate, and skill level of operators all play a role in determining the vertical kiln's calcining zone's height and location. The calcining zone is the lower portion of the Rotary Kiln (about 10–15% of the total kiln height) where the material is heated.

The Cooling Zone

The calcined clinker transfers its heat to the cold air blasted upwards from the bottom of the cooling zone. Air is heated while the clinker is being cooled and then flows upward into the calcining zone, which aids in the combustion process.

Conclusion

With cutting-edge equipment, KINC Mineral Technologies produces only the finest vertical kilns from the finest quality components. For our customers, we also provide a service of personalization. In addition to being given within the promised time range, this service is also offered at highly reasonable rates.

For vertical kilns, we are the go-to supplier. Shaft kilns employ a counterflow system, with raw materials moving away from the hot gas. We are the best Vertical Shaft kiln Exporters in India.

Different Structures and Operations for the Vertical Shaft Kiln

Smaller and medium-sized cement facilities often employ vertical shaft kilns, also known as vertical kilns, to calcine clinker. The entire feeding, calcining, crushing, and discharging process can be automated.

Before the rotary kiln was conceived, vertical kilns were commonly employed in cement companies worldwide. The Vertical Shaft Kiln was the traditional kiln used to make cement until the rotary kiln came along in the 20th century. Many cement manufacturers in nations like India, however, are still using vertical kilns.

Structures and Operation of Shaft Kilns:

Vertical Shaft Kiln Suppliers in India provide disc pelletizers in vertical kiln cement plants that turn ground raw materials into wet pellets by adding 12-14% water to the pelletizing pan. After calcination, the wet pellets are released from the kiln's bottom.

The interior of the vertical kilns is segmented into three distinct zones, designated by their respective temperatures during operation: the preheating zone, the calcining zone, and the cooling zone.

The Preheating Zone

When wet pellets are placed in a kiln, the hot air circulating from the bottom to the top of the kiln causes the water inside the pellets to evaporate.

Simultaneously, the fuel's volatile components constantly evaporate as the temperature rises. Because the hot air flow contains no oxygen, the flammable material is not burned but released into the atmosphere together with the exhaust gas.

The ball of material continues to sink deeper into the vertical kilns as the kilns heat up due to gravity. Dehydration of the kaolin occurs between 500 and 600 °C, and the carbonate begins to disintegrate, and a portion of the solid-state reaction takes place at temperatures above 700 °C.

Only 5- 10% of the kiln's overall height is devoted to the actual body, where temperatures range from 20 to 1000 degrees Celsius.

The Calcining Zone

As the raw material enters the calcining zone, its temperature will continue to rise above 1000 °C.

Most of the coal in the raw material begins to burn at this point, causing a rapid rise in temperature and a multitude of solid-state reactions; the exothermic solid-state reaction causes the temperature to soar to well above 1300 °C, at which point the material enters a liquid phase and the sintering stage.

Coal in the raw material, coal quality, pellet size, air flow condition, pre-homogenization of the raw material, discharge speed, and operational level all influence the height and position of the calcining zone in the vertical kilns. The calcining zone is the area just below the kiln's expansion port, and it typically takes up only 10–15% of the kiln's overall height.

The Cooling Zone

In a Vertical Shaft Kiln, the calcined clinker moves through the cooling zone, it loses heat to the cold air being sucked up from below. After the clinker has been cooled, the air is heated and sent upwards into the calcining zone, which aids in the combustion process.

Leading Manufacturers of Shaft Kilns: 

We at Kinc Group are a cement plant project contractor and equipment maker. Worldwide, our clients can count on us for turnkey solutions to their vertical kiln cement plant solutions. Due to the renowned goodwill in the market, Kinc Group is considered to be the best Vertical Shaft Kiln Exporters in India.

The Vertical Shaft Kiln And The Role Of Refractory Lining In It!

A Vertical Shaft kiln is a stationary production systems in which the raw material like limestone of  different particle sizes gets fed into the kiln from the top, where it then flows downhill via the kiln shaft alone due to the force of gravity. This process is known as "drying" the limestone. A chemical event known as dissociation takes place when heat energy in the form of fuel is introduced into the system. This reaction causes the limestone (CaCO3) to be broken down into lime (CaO) and carbon dioxide (CO2).

In spite of the fact that the vertical shaft kiln come in a variety of configurations and sizes and gets utilised in a wide variety of industries (lime, sugar, soda, iron and steel, etc.), one thing that all of these kilns have in common is that the refractory linings inside of them always consist of multiple layers. In most cases, this will include a number of insulating layers, in addition to the worn lining and the permanent lining. In the same vein, a shaft kiln's zones may often be broken down into three distinct categories: the preheating, calcining, and cooling zones.

The Importance Of Refractory Lining 

Because the filled shaft kiln generally depicts a column of limestone that rises up to the feeding area and is penetrated by a flow of hot combustion gases, the strains that are placed on the refractory lining are considerably different from those that are placed on the lining of a rotating kiln. Because of the heat transfer that occurs through the various refractory layers as well as the particular temperature limitations of the insulating materials, the insulating layer is often built up using anywhere from one to three layers of insulating material. The shell temperature is going to have to be brought down to a certain maximum value, and the insulating layer's job is to make that happen.

The Permanent Lining 

To reduce the temperature on the insulation layer side, and to function as an "emergency liner" if the wear lining fails, the top Vertical Shaft Kiln Manufacturers In India sandwiches the permanent liner between the wear liner and the insulating layer.

The Wear Lining 

Because the wear lining is in direct and constant contact with the kiln charge as well as the hot gases, it is necessary for it to have a high level of thermal and chemical resistance in addition to a high level of strength against hot and cold mechanical abrasion. In a shaft kiln, the degree of mechanical adaptability that is necessary for a rotary kiln is of far less significance.

Consult Expert Suppliers!

KINC Mineral Technologies Pvt. Ltd. is the leading Vertical Shaft Kiln Suppliers In India. Our R&D team keenly measures each aspect of these linings and the temperature levels of different materials. We also customise our goods and services as per the needs of our clients. If you want to experience our highly advanced technology, get in contact with us through our website.