Clay aggregate rotary kiln Introduction

Clay aggregate rotary kiln structure

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.

Rotary kiln pinion: The pinion is an essential part of the rotary kiln drive system, responsible for transmitting rotational motion and torque from the driving mechanism to the rotary kiln itself. It consists of a gear wheel with teeth that mesh with the teeth of a larger gear, often referred to as the "girth gear" or "ring gear." The girth gear is attached to the outer shell of the rotary kiln. When the pinion is rotated by the drive system, it drives the girth gear, causing the rotary kiln to rotate.

Rotary kiln bearing housing: The bearing housing serves as the support structure for the kiln's rotating motion and is responsible for holding and guiding the kiln's trunnion bearings. Trunnion bearings are large, heavy-duty bearings that support the weight of the kiln and allow it to rotate smoothly. These bearings are subject to high loads, extreme temperatures, and potentially harsh environments due to the nature of the processes occurring inside the rotary kiln. The bearing housing provides a stable mounting point for the trunnion bearings and ensures proper alignment of the kiln's rotation. It is typically designed to accommodate the axial and radial forces generated during the rotation of the kiln.

Kiln Shell: The rotary kiln shell is a thick, steel cylindrical structure that provides the necessary strength and rigidity to withstand the high-temperature environment inside the kiln. It also serves as a containment vessel for the materials and gases during the manufacturing process. Inside the kiln shell is the refractory lining usually refractory bricks or sometimes refractory castable. Tongli kiln shell has good sealing performance, the edge of each shell is machined smoothly, enhance the sealing and service life of the rotary drum.

Kiln Hood Cover: The rotary kiln hood is located at the discharge end of the kiln and provides sealing to retain heat and gases. The rotary kiln operates under the negative pressure, therefore Tongli implied SS304 lining plate and ceramic felt both in the front and back end to prevent heat leakage.

Rotary Kiln Transmission device: The transmission device of the rotary kiln is mainly composed of main transmission, auxiliary transmission, mechanical thrust roller/hydraulic thrust roller, motor, gearbox and other components. The unique design of tongli transmission can greatly improve the service life and safety performance of the equipment.

PLC control system: A PLC is a digital computer-based system that is designed to control various industrial processes automatically. In the context of a rotary kiln, a PLC is used to monitor and control parameters such as temperature, rotation speed, air flow, fuel flow, and other critical variables that affect the performance of the kiln and the quality of the products being processed. Usually, the rotary kiln control system is integrated in the whole factory’s plc system, therefore we will provide the on-site cabin and a signal cable to the central plc.

Design principles of clay aggregate rotary kiln

Material Properties: Understand the physical and chemical properties of the clay aggregate being processed. This includes characteristics such as particle size distribution, moisture content, plasticity, shrinkage, and thermal behavior. These properties will influence the design of the kiln's dimensions, speed, and other operational parameters.

Kiln Geometry and Size: Determine the appropriate size and geometry of the rotary kiln based on the production capacity and material properties. The kiln's length, diameter, inclination, and rotation speed all impact the heat transfer, residence time, and overall efficiency of the process.

Heat Transfer: Optimize the heat transfer mechanisms within the kiln to ensure efficient processing. This involves designing the kiln's internal flights, baffles, and other components that enhance heat exchange between the material and the hot gases.

Kiln Lining and Insulation: Select suitable refractory materials for the kiln lining that can withstand high temperatures and corrosive conditions. Proper insulation is also crucial to minimize heat loss and improve energy efficiency.

Fuel and Combustion System: Choose an appropriate fuel source and combustion system that aligns with the energy requirements of the process. Consider factors like fuel availability, combustion efficiency, and environmental regulations.

Air Flow and Gas Circulation: Design the kiln's air and gas flow patterns to ensure uniform temperature distribution and material processing. Efficient gas circulation prevents hot spots and uneven processing.

Temperature Control: Implement temperature monitoring and control systems to maintain consistent and accurate temperature profiles along the length of the kiln. This helps achieve the desired material transformation without over- or under-processing.

Safety Features: Integrate safety mechanisms such as temperature alarms, pressure sensors, and emergency shutdown systems to prevent accidents and equipment damage.

Specifications of clay aggregate rotary kiln

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

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Industry Knowledge extension

What is the application of calcined clay aggregate?

Calcined clay aggregate, also known as expanded clay aggregate (ECA) or lightweight expanded clay aggregate (LECA), is a lightweight, porous material produced by heating clay to high temperatures. It finds a variety of applications across different industries due to its unique properties.

Lightweight Concrete: Calcined clay aggregate is used as a lightweight aggregate in concrete to reduce the overall weight of structures while maintaining structural integrity. Lightweight concrete is particularly useful in situations where weight reduction is important, such as in high-rise buildings and bridge decks.

Insulating Concrete: Due to its low thermal conductivity, calcined clay aggregate is used to produce insulating concrete blocks, panels, and roof tiles.

Green Roof Substrate: Calcined clay aggregate is used as a lightweight substrate in green roofs, where its porous structure allows for water retention and root penetration.

Hydroponics and Aquaponics: Calcined clay aggregate is used as a growing medium in hydroponic and aquaponic systems. Its porous nature provides good aeration and water retention for plant roots.

Athletic Tracks and Fields: Calcined clay aggregate is used as a base material in athletic tracks and fields to provide proper drainage and maintain a consistent playing surface.

Acoustic Panels: Calcined clay aggregate is used as a component in sound-absorbing panels and materials due to its porous structure and ability to dampen sound.

Fire-Resistant Materials: Calcined clay aggregate can be used in the production of fire-resistant materials and coatings due to its high-temperature stability.

Thermal Insulation: Calcined clay aggregate is used as thermal insulation in industrial applications, such as lining furnaces and kilns.

Art and Craft:

Water and Wastewater Treatment: Calcined clay aggregate can be used as a filter media in water and wastewater treatment processes to remove suspended solids and pollutants.

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

The rotary kiln and vertical roller mill are both essential pieces of equipment in the cement manufacturing process, but they serve different purposes and are used at different stages of the process.

The rotary kiln is a large cylindrical vessel used for calcining raw materials at high temperatures. It's a core component of the cement manufacturing process and is responsible for transforming raw materials, particularly limestone and clay, into clinker. In the rotary kiln, the raw materials are heated to temperatures exceeding 1400°C (2552°F), where chemical reactions occur that result in the formation of clinker nodules. And they need to be ground into a fine powder to produce cement. This final grinding process is often performed using a vertical roller mill. The clinker is mixed with gypsum and possibly other additives to create the final cement product.

Vertical Roller Mill (VRM): The vertical roller mill is a grinding machine that grinds materials into fine powders, after the raw material is crushed by the crusher, it enters the vertical roller mill. It is typically used for grinding raw materials, clinker, and additives in the cement manufacturing process. The VRM operates by applying hydraulic pressure and vertical force to the grinding rollers, which then grind the materials between the rollers and the grinding table. This grinding process results in a fine powder that is later used as a key ingredient in the production of cement which is important for the subsequent chemical reactions in the rotary kiln.