Mineral powder rotary dryer Introduction

Mineral powder rotary dryer structure

Tongli minetal powder rotary dryer is a kind of drying equipment that can handle a large number of mineral powders. The mineral powder rotary dryer is composed of, dryer shell, dryer riding ring, dryer girth gear, dryer transmission unit, dryer hood cover and so on.

Dryer Shell: The rotary dryer shell is the main body of the dryer, where the material is loaded and rotated. It has a cylindrical shape and is equipped with lifting plates or flights to lift and disperse the material. The drum is heated by hot air or gas that flows through it, either in parallel or countercurrent direction. The drum transfers heat to the material and evaporates the moisture.

Dryer Flights: Rotary dryer flights, also known as "flights" or "lifters," are the inclined, curved structures that are attached to the internal shell of a rotary dryer. A rotary dryer is a device used to remove moisture from materials like powders, granules, and bulk solids through the process of drying. It consists of a large cylindrical drum that rotates while the material is fed into one end and is discharged from the other end after being dried.

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

Dryer pinion: The pinion is an essential part of the rotary dryer drive system, responsible for transmitting rotational motion and torque from the driving mechanism to the rotary dryer 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 dryer. When the pinion is rotated by the drive system, it drives the girth gear, causing the rotary dryer to rotate.

Dryer bearing housing: The bearing housing serves as the support structure for the dryer's rotating motion and is responsible for holding and guiding the dryer's trunnion bearings. Trunnion bearings are large, heavy-duty bearings that support the weight of the dryer 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 dryer. The bearing housing provides a stable mounting point for the trunnion bearings and ensures proper alignment of the dryer's rotation. It is typically designed to accommodate the axial and radial forces generated during the rotation of the dryer.

Dryer Hood Cover: The rotary dryer hood is located at the discharge end of the kiln and provides sealing to retain heat and gases. The rotary dryer 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 dryer Transmission device: The transmission device of the rotary dryer 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 dryer, 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 dryer and the quality of the products being processed. Usually, the rotary dryer 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 mineral powder rotary dryer

Advanced design: Thedrying process of the mineral powder dryeris advanced, adopting a high-temperature rapid drying process, with alarge heat transfer coefficient, high thermal efficiency and strong dryingintensity. Thecombination of high-speed stirring drying and airflow drying can fullydisperse the sticky materials, greatly increasing the contact area betweenthe materials and the heat medium, which is conducive to the dryingprocess.

Self-cleaning device: Themineral powder dryer adopts a specialscraping device to avoid the phenomenon of material sticking to the wall.

Versatility: It has a wide range of applications, simple operation, low maintenance, andstable product quality.

Themineral powder dryer is specially designedfor drying mineral powder, with features such as variable rotating bladeangle and adjustable shaft speed.

Large capacity: Tongli mineral powder rotary dryer has a large processing capacity, strong overload resistance, high thermal efficiency and low coal consumption, which reduces the drying cost by about 20%.

Energy efficiency: In order to achieve the best drying effect, Tongli Chemical raw material rotary dryer adopts the counter-current drying method. The material and the heat source enter the drying equipment from the other side. Chemical raw material rotary dryer has the feature of high temperature resistance, and can use high temperature hot air to quickly dry the materials.

Flights: The equipment has made many technical innovations in the lifting device system, especially adopting a new type of multi-combination lifting device, which overcomes the “wind tunnel” phenomenon of traditional dryers.

Heat Transfer Efficiency: The primary purpose of a rotary dryer is to remove moisture from the lignite through heat transfer. Efficient heat transfer is achieved by maintaining good contact between the lignite particles and the hot drying medium (usually air or combustion gases). The design should ensure optimal mixing and dispersion of lignite within the dryer to maximize heat transfer efficiency.

Drying Medium Flow: Proper flow of the drying medium is crucial. The design should facilitate a consistent and controlled flow of hot air or combustion gases through the dryer to evenly distribute heat and moisture removal throughout the lignite bed.

Temperature Control: Careful temperature control is necessary to prevent over-drying or under-drying of lignite. The design should include mechanisms to monitor and adjust the drying temperature based on the moisture content of the lignite.

Retention Time: The time lignite spends in the rotary dryer, known as retention time, impacts the drying efficiency. Design considerations should ensure that the retention time is sufficient for moisture removal while avoiding overexposure that could lead to degradation of lignite quality.

Specifications of mineral powder rotary dryer

Note: *The initial moisture is assumed to be 2~6% and final moisture is 1~4%; Inlet temperature of hot air is 150~250 Celsius and outlet temperature is 70~90 Celsius; Production Capacity will vary according to the composition and moisture of the material.

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Industry Knowledge extension

What is the difference between ball mill and vertical roller mill?

Both ball mills and vertical roller mills plays a vital role in the cement grinding plant. Ball mills are versatile and cost-effective, suitable for various materials and simple to maintain. On the other hand, vertical roller mills offer superior energy efficiency and particle size control, making them ideal for cement and ore grinding applications. The choice between the two depends on specific requirements, budget constraints, and technical expertise.

What is the difference between rotary dryer and rotary kiln?

Rotary dryer: A rotary dryer is used to remove moisture from materials, such as minerals, ores, chemicals, food products, and biomass. The primary purpose of a rotary dryer is to reduce the moisture content of the material through the application of heat and the movement of the material within the drum. In a rotary dryer, materials are fed into the rotating drum, and hot gases or air are introduced to evaporate the moisture. The material is tumbled and agitated as it moves through the drum, allowing for efficient drying. Rotary dryers operate at elevated temperatures to facilitate drying, the temperatures used are generally lower compared to those in rotary kilns. Rotary dryers are used in industries such as agriculture, mining, chemicals, and food processing to remove moisture from bulk solids, powders, and other materials.

Rotary Kiln: A rotary kiln is designed for high-temperature processes, such as calcination, sintering, pyrolysis, and other thermal treatments. It's used to process raw materials or products at elevated temperatures, often in a controlled atmosphere, to bring about physical or chemical changes in the material. In a rotary kiln, materials are typically fed into one end of the kiln and gradually move towards the other end. The kiln is heated to very high temperatures, and the material undergoes chemical reactions, phase changes, or thermal treatments as it progresses through the kiln. Rotary kilns operate at much higher temperatures, often reaching well over 1000 degrees Celsius (1800 degrees Fahrenheit), depending on the specific process. These high temperatures are necessary to achieve the desired chemical or physical transformations in the material. Rotary kilns are used in industries such as cement production, lime calcination, metallurgy, and waste incineration. They are designed for processes that require high-temperature reactions, phase changes, or material transformation.