Sand rotary dryer Introduction

Sand dryer, also known as river sand dryer or yellow sand dryer, is a kind of drying equipment that can handle a large number of sands. It has reliable operation, large operation flexibility, strong adaptability, and large processing capacity. River sand dryer is generally suitable for granular materials, and it can dry yellow sand, river sand, and other materials with excellent effects. The advantages of river sand dryer include large production capacity, wide application range, low flow resistance, large allowable fluctuation range in operation, and easy operation. It is often used for drying river sand, artificial sand, sand, ore powder, coal slag and other materials. The hot air furnace provides hot air for the sand dryer, the hot air enters the cylinder from the lower end, and contacts with the wet sand in a counter-current way. The wet sand is heated by the hot air, and the moisture evaporates. The dried sand is discharged from the other end of the cylinder by the discharge chute.

Sand rotary dryer structure

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 sand rotary dryer

The design principles of a sand rotary dryer are centered around efficient drying of sand or other materials through the use of a rotating drum and hot air flow. The primary goal of a sand rotary dryer is to reduce the moisture content of the material to a level suitable for its intended use. Here are the key design principles of a sand rotary dryer:

Advanced design: Tongli Sand rotary dryer the overall length is 60% shorter than that of a single-cylinder dryer, which is conducive to process layout. Reduce the building area of the plant, save about 40% of the project investment.

Rotating Drum: The core component of a sand rotary dryer is a rotating drum or cylinder. This drum is inclined slightly from the horizontal and rotates on its axis. The material (in this case, sand) is fed into one end of the drum and moves slowly towards the discharge end due to the rotation.

Heat Source: A heat source is required to provide the energy necessary for drying. This is  achieved by introducing hot air or combustion gases into the rotary dryer. Common heat sources include natural gas burners, coal-fired furnaces, or even waste heat from other industrial processes.

Flights or Lifters: Flights or lifters are attachments mounted on the interior surface of the drum. They help to lift and cascade the material as the drum rotates. This movement exposes the material to the hot air, ensuring even and efficient drying by maximizing the contact between the material and the hot air.

Material selection: Tongli Sand rotary dryer adopts heat-resistant and wear-resistant alloy steel plate, which is 4 times more wear-resistant than ordinary steel plate. Long service life and easy maintenance.

Efficiency: Tongli Sand rotary dryer features thermal efficiency, the outer barrel temperature is lower than 60 degrees (the single-cylinder dryer outer barrel temperature is as high as 150 degrees), the outlet temperature is low, and the discharge temperature is lower than 60 degrees.

Feeding and discharging: Tongli Sand rotary dryer uses a new type of feeding and discharging device, which prevents the Sand rotary dryer from feeding blockage, discontinuity, unevenness and return phenomena, and reduces the load of your dust removal system. 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.

Scalability: Tongli Sand rotary dryer has strong scalability, and the design considers the production margin. Even if the output increases slightly, there is no need to replace the equipment.

Specifications of sand 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.

HIGH-TECH ENTERPRISES

Modern intelligent processing base integrating R&D, production and sales.

Zhejiang Tongli Heavy Machinery Manufacturing Co., Ltd (Formerly known as Tongxiang Coal&Mining Machinery Factory) established in year 1958 is a member of the Chinese National Building Material Machinery Association. Tongli is on the vendor list of designated production enterprise of the Ministry of Coal Industry. ISO9001、ISO14001、ISO45001 certified, accredited as High-tech & new technology enterprise of Zhejiang Province. With 65+ years of experience, Tongli has earned first class R&D and manufacturing capabilities, dedicated to provide satisfactory manufacturing equipments for global customers.   

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.