The ring die granulator is a widely used pelletizing machine. It utilizes a mechanical extrusion granulation process and holds a significant position in the pellet production market due to its high efficiency and stable performance. Its core operating principle is to feed pre-treated material between a ring die and a pressure roller. The pressure roller rotates under power, exerting a force on the material, forcing it through the die holes in the ring die to form columnar pellets. This is then cut into pellets of a predetermined length by a cutting device.
This granulation method eliminates the need for complex drying processes and effectively preserves the nutrients and active ingredients in the material while ensuring pellet quality. Compared to other granulation equipment, the ring die granulator offers high production efficiency, with a single machine output of several to tens of tons. The pellets produced are dense and strong, making them suitable for large-scale industrial production.
Fertilizer field: It can produce various organic fertilizers, inorganic compound fertilizers, bio-organic fertilizers, etc. It can ferment organic waste such as livestock and poultry manure and crop straw into granular fertilizers, solving the problems of inconvenient transportation and easy agglomeration of organic fertilizers.
It can also be used to produce special fertilizers such as slow-release fertilizers and controlled-release fertilizers. By adjusting the raw material formula and granulation process parameters, the precise release of fertilizer nutrients can be achieved to meet the nutrient needs of different crops at different growth stages.
Feed industry: It is a key equipment for producing pellet feed for livestock, poultry, aquatic products, etc. It can mix corn, soybean meal, bran and other raw materials according to the formula and then granulate them, thereby improving the digestibility and absorption rate of feed, reducing feed waste, and pellet feed is easy to store and transport.
Biomass energy industry: Biomass raw materials such as wood chips, straw, and rice husks can be made into high-density pellet fuel. This fuel has high combustion efficiency and low pollution, and can replace traditional coal in industrial boilers, home heating and other fields.
Chemical industry: Suitable for granulation of chemical raw materials such as catalysts, pigments, detergents, etc. Granulation can make these chemical products have better fluidity, stability and performance.
Forestry industry: Wood processing waste can be made into wood pellets for the production of artificial boards, activated carbon and other products, thus realizing the recycling of resources.
Feeding device: It consists of a hopper, a screw conveyor and a conditioner. The hopper is used to temporarily store the material to be granulated. Its capacity depends on the production scale and is generally 1-10 cubic meters.A screw conveyor transports the material from the hopper to the conditioner. The conveying speed is adjustable by a variable frequency motor to ensure uniform and stable feeding. The conditioner conditions the material by introducing steam or adding moisture or binders, bringing it to an appropriate humidity and temperature, improving its plasticity and cohesiveness for subsequent granulation.
Ring die: It is the core component of the ring die granulator. It is forged with high-strength alloy steel. After heat treatment, the surface hardness can reach HRC55-65, and it has extremely high wear resistance and pressure resistance.The ring die is cylindrical in shape, with numerous holes evenly distributed along its inner wall. The hole diameter typically ranges from 2 to 20 mm, and can be selected based on the desired pellet size. The hole arrangement and aperture ratio are optimized to ensure uniform force distribution across the material, improving pelletizing efficiency and pellet quality.
Pressure roller: There are usually 2-3 rollers evenly distributed inside the ring die, made of wear-resistant cast iron or alloy steel. The surface of the roller is usually processed with special patterns or grooves to increase friction with the material, prevent the material from slipping, and ensure that the material can be smoothly brought into the space between the ring die and the roller for extrusion.The gap between the pressing roller and the ring die can be precisely adjusted through the adjusting device to meet the granulation requirements of different materials.
Cutting device: It consists of blades and a drive mechanism and is installed on the outside of the ring die. The blades are made of high-speed steel or alloy tool steel, which is sharp and wear-resistant.By adjusting the position and rotation speed of the blade, the length of the particles can be precisely controlled to meet the specification requirements of different products.
Drivetrain: It consists of a motor, a reducer, a coupling, etc. The motor provides power, and the power depends on the equipment model and production capacity, generally 15-160kW.The reducer converts the high-speed rotation of the motor into low-speed rotation of the ring die or roller. This power is then transferred to the working parts through the coupling, ensuring coordinated operation of all parts of the equipment. Some equipment uses a variable frequency speed control system, which allows for flexible adjustment of the ring die speed to suit the pelletizing characteristics of different materials.
Raw material pretreatment: For organic fertilizer raw materials, they must first be fermented and decomposed. The fermented materials are crushed and sieved to make the particle size reach 60-100 mesh to ensure the granulation effect.For compound fertilizers, basic fertilizers such as nitrogen, phosphorus, and potassium should be accurately measured according to the formula ratio and then mixed. The mixing uniformity should reach more than 90%, and the moisture content of the mixed materials should be controlled between 8% and 15%.
Quenching and tempering treatment: The pretreated material enters the conditioner, where an appropriate amount of steam (or water or binder) is introduced according to the material characteristics to raise the material temperature to 60-80°C and adjust the moisture content to 12%-18%. The conditioning makes the material soft and sticky, making it easier to extrusion and granulation.
Extrusion granulation: The quenched and tempered material enters between the ring die and the pressure roller. The pressure roller rotates under the drive of the transmission system, exerting a strong extrusion force (generally 20-50MPa) on the material, so that the material overcomes the resistance of the ring die hole and is squeezed into columnar particles and squeezed out of the die hole.
Cutting and cooling: The cylindrical particles extruded from the die hole are cut into particles of a set length (usually 2-10 mm) by the cutting device outside the ring die.The temperature of the pellets after cutting is high and they need to enter cooling equipment (such as cooling fans, cooling cylinders) for cooling to reduce the pellet temperature to room temperature to prevent the pellets from agglomerating and deteriorating.
Screening and packaging: The cooled particles are screened by screening equipment to separate unqualified particles (too large, too small or broken particles), and the unqualified particles are returned for re-granulation.Qualified granular fertilizers are packaged after being measured. The packaging materials can be woven bags, plastic bags, etc., which are convenient for storage and transportation.
High production efficiency: The ring die granulator adopts a continuous production method with high output per machine, ranging from a few tons to dozens of tons, which can meet the needs of large-scale industrial production and greatly improve production efficiency.
Excellent particle quality: The fertilizer particles produced have high density and strength, generally reaching 25-60N. The particles have regular shape, smooth surface and high uniformity. They are not easy to break or clump during storage, transportation and use, and have good fluidity.
Wide adaptability of raw materials: It can process various fertilizer raw materials, whether organic, inorganic or a mixture of the two, and can achieve good granulation results. It also has strong adaptability to raw materials containing a certain amount of fiber and moisture.
High degree of automation: Equipped with a complete automatic control system, it can accurately control the feed rate, tempering parameters, ring die speed, cutting length, etc., to achieve automated production, reduce manual intervention, and improve production stability and product quality consistency.
Easy operation and maintenance: The equipment has a rational structure design and a simple and easy-to-understand operation interface, allowing operators to take up their posts after simple training. Wearing parts are easy to replace, and daily maintenance workload is minimal, effectively reducing production management costs.