Rotary kiln shell Introduction

A rotary kiln shell refers to the cylindrical outer structure of a rotary kiln, the shell of a rotary kiln is made up of a steel or other heat-resistant material casing that encloses the rotating components and the material being processed inside the kiln. The shell provides structural support and containment for the high-temperature and sometimes chemically aggressive environment within the kiln. It also helps in retaining heat to facilitate the desired processes. The rotary kiln shell is often lined with refractory materials on the interior to protect it from the extreme temperatures and corrosive gases generated during the processes taking place inside the kiln. This lining helps prolong the life of the shell and maintain its integrity. Tongli, as a professional rotary kiln parts supplier, provides various types of rotary kiln shell with different specifications and materials. We have specialized equipment that is only used to manufacturer rotary kiln, for example we have a 6.5x6.5x20m annealing furnace and also 6.5x6.5x20m sandblasting room that we are able to do the annealing of the rotary kiln by whole and the sandblasting as well. We have integrated the cutting-edge technology into our equipment design.

Cement rotary kiln structure

A rotary kiln is a large cylindrical vessel used for a variety of processes, such as drying, calcination, and chemical reactions. It's commonly used in industries like cement production, lime manufacturing, and more. The structure of a rotary kiln can vary depending on its specific application, but I'll provide a general overview of its typical components and construction:

Shell: The main cylindrical body of the rotary kiln is called the shell. It is typically made of steel and lined with refractory materials to withstand high temperatures and chemical reactions. The shell is inclined slightly from the horizontal and rotates on its axis.

Riding Rings and Rollers: The shell is supported by a set of riding rings and rollers. The riding rings are large rings that encircle the shell at various intervals along its length. The rollers, placed between the riding rings, support the weight of the kiln and allow it to rotate smoothly.

Tyres (Tires): Tyres are large, circular steel components that are attached to the shell. They usually have a conical shape to provide support and help distribute the load evenly. Tyres are sometimes fitted with riding pads to further reduce friction and wear.

Girth Gear: The girth gear is a large ring gear that is attached to the shell and meshes with a pinion gear. This arrangement drives the rotation of the kiln. The girth gear is often supported by trunnion rollers to maintain proper alignment.

Pinion Gear: The pinion gear is a smaller gear that meshes with the girth gear. It is usually driven by a motor through a gearbox, which imparts the rotational motion to the kiln.

Rotary kiln thrust roller：The thrust roller is a critical part of the rotary kiln system. It serves the purpose of supporting the kiln's weight and maintaining its axial position, ensuring that the kiln remains properly aligned along its axis. The thrust roller is typically positioned on the downhill side of the kiln and is attached to the kiln shell. It consists of a central shaft or journal and a roller assembly.

Supporting Rollers: Supporting rollers are additional rollers placed along the length of the kiln to help prevent excessive deflection of the shell due to thermal expansion and other forces. They play a crucial role in maintaining the kiln's stability and alignment.

Refractory Lining: The interior of the kiln is lined with refractory materials to protect the shell from the high temperatures and chemical reactions occurring inside. Different sections of the kiln might have different types of refractories to withstand varying conditions.

Design principles of cement rotary kiln shell

Material Selection: The rotary kiln shell is typically made from steel or other materials with suitable strength and durability. Carbon steel, stainless steel, and high-strength alloy steels are common choices due to their ability to withstand the mechanical stresses and abrasive forces generated during grinding.

Forming: The shell is usually fabricated from flat steel plates. The plates are cut, bent, and welded to form the cylindrical shape of the rotary kiln shell. The size and thickness of the plates depend on the specifications of the rotary kiln and the materials being processed.

Welding: The steel plates are welded together to create a seamless cylindrical shell. Welding processes such as submerged arc welding or gas metal arc welding are commonly used to ensure the integrity and strength of the welds.

Inspection and Quality Control: Throughout the manufacturing process, inspections and quality control checks are performed to ensure the accuracy of measurements, the integrity of welds, and the overall quality of the shell. Non-destructive testing methods such as ultrasonic testing or magnetic particle testing might be used to detect any defects or irregularities.

Surface Treatment: After the rotary kiln shell is fabricated and welded, it undergoes surface treatment to enhance its corrosion resistance and durability. This may involve processes such as shot blasting, sandblasting, or applying protective coatings to prevent rust and wear.

Final Machining: Depending on the specific requirements of the rotary kiln shell, the shell might undergo final machining processes to achieve precise dimensions and tolerances. Machining ensures that the flanges, trunnion seats, and other critical areas are accurately shaped and aligned.

Transportation and Installation: Once the rotary kiln shell is manufactured, it is transported to the site where it will be installed. Proper handling and transportation are essential to prevent damage to the shell during transit. During installation, the shell is carefully aligned and connected to the mill's drive system and other components.

Specifications of cement rotary kiln shell

Note: *The diameter is the inner diameter, Weight excludes refractory material.

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Industry Knowledge extension

What is the step Prior to the rotary kiln calcination?

The first step of making cement is the raw material crushing, conveying and storage. The limestone raw material from the mine needs to be crushed, ground and mixed, and the crushing process is carried out by cement crusher. When the maximum size of the input ore is ≤1600mm and the output particle size is ≤80mm, the limestone discharged from the crusher is then sent to the Φ80m circular pre-homogenization yard by the belt conveyor for pre-homogenization and storage.

What is the relationship between vertical roller mill and rotary kiln?

The rotary kiln is usually used as an intermediate process. The large raw materials are crushed by the crusher and then enter the grinding equipment for grinding. After being mixed with other raw materials, they are added to the rotary kiln for redox reactions. The calcined finished products need to enter the vertical roller mill or ball mill for secondary grinding to get the finished product.