Fertilizer Granules Compaction Machine Introduction
A roller extrusion granulator, also known as a double roller press granulator, is a molding machine that uses a pair of opposing rotating extrusion rollers to directly compress powdery materials into granules of a specific shape under high pressure.
This equipment adopts a dry extrusion granulation process, directly compressing dry powder materials into granules at room temperature. It primarily uses physical extrusion pressure to shorten the distance between material molecules and generate binding forces, thereby transforming loose powdery materials into granules with a certain strength and shape. The binding force between granules originates from intermolecular forces such as van der Waals forces, adsorption forces, crystal bridges, and embedded connections. This completely solves the pain points of traditional wet granulation processes, such as cumbersome processes, high energy consumption, and severe nutrient loss. Furthermore, this equipment features advanced technology, reasonable design, compact structure, and low energy consumption. It can be used as a standalone unit or combined with multiple units to form a mechanized continuous production line.
Structural Components of a Fertilizer Granules Compaction Machine
The double-roller press granulator mainly consists of the following core components:
Frame and Base:Welded from heavy-duty channel steel or castings, it bears the weight of the entire machine and ensures stability under high pressure.
Transmission System:Typically composed of a motor, pulleys, reducer, and gear transmission. It provides synchronous and opposite rotational power to the two rollers.
Pressure Roller Assembly (Core Component):Consists of two horizontally mounted, parallel rollers. One is a fixed shaft (main shaft), and the other is an adjustable shaft (passive shaft). The shafts are fitted with specially heat-treated roller skins. The roller skin surfaces are engraved with spherical, strip-shaped, or flattened spherical grooves, determining the shape and size of the finished granules.
Pressure Adjustment System (Spring or Hydraulic System):Used to adjust the extrusion pressure between the two rollers to accommodate different material hardness requirements and provides overload protection.
Feeding Mechanism:Usually equipped with a forced feeder (such as a screw conveyor) to ensure that the material is fed evenly and continuously into the angled area between the two rollers. Crushing and screening system: Some models come with crushing rollers and vibrating screens to crush the extruded cake material into particles of a specified size and separate the powder for recycling and granulation.
Working Principle of Fertilizer Granules Compaction Machine
The basic principle of double roller press granulator is "pressure forming." When material enters between two pressure rollers, it is drawn into the narrow gap as the rollers rotate. During this process, air inside the material is expelled, and the distance between molecules is forcefully shortened, resulting in plastic deformation. When the pressure exceeds the material's yield point, the powder agglomerates into dense flakes or pre-shaped blanks. Subsequently, it is demolded and crushed under the action of gravity or a crusher.
Its working principle can be summarized as: forced feeding -> compaction forming -> crushing and demolding -> screening and grading.
Material Feeding: Material enters through the feed hopper and is evenly fed between two counter-rotating pressure rollers by a forced feeding screw.
Extrusion Forming: As the rollers rotate, the material is forcibly bitten into the roller gap. The contact pressure increases sharply as the material moves closer to the center line of the roller shaft. At the roller gap (the point of maximum pressure), the material is compressed into dense flakes or spheres.
Demolding and Crushing: After passing through the roller gap, the pressure is rapidly released, and the formed "cake" falls off due to elastic recovery and its own weight, entering the crusher for coarse crushing.
Screening and Recycling: The crushed material enters the screening machine; qualified particles enter the finished product bin; undersized powder and oversized large particles are returned to the raw material end via a conveyor for regranulation.
Application of Fertilizer Granules Compaction Machines in Production Lines
In a complete fertilizer production line, the double-roller press granulator is typically the core granulation equipment, used in conjunction with the upstream raw material crushing, batching, and mixing systems, and the downstream granule screening, packaging, and conveying systems. Because it eliminates the need for dryers and coolers, the floor space of the entire production line can be reduced by more than 50%, significantly lowering equipment investment and operating energy consumption. It enables continuous, automated production, improving production efficiency and product consistency, and its application is particularly mature in fertilizer, organic fertilizer, and pharmaceutical production lines.
Granulation Process of Fertilizer Granules Compaction Machine
Double roller press granulation is a dry granulation method, requiring little or no liquid binder. Generally, the raw material is first crushed to a certain particle size, then the moisture content is adjusted, and then it is evenly fed into the rollers for extrusion through a mixing and batching system. After extrusion, the granules directly enter the screening and shaping stage. Compared with wet granulation, this process is simpler, consumes less energy, and eliminates the need for subsequent drying, improving production efficiency and product environmental friendliness.
A typical process flow for roller extrusion granulation is as follows:
Feeding preparation → Automatic batching → Uniform mixing → Roller extrusion → Coarse crushing/crushing → Screening and grading → Finished product packaging
Key process control points:
Roller gap: Directly affects extrusion pressure and sheet thickness, generally controlled between 1.5mm and 3.5mm.
Roller speed: Linear speed is typically 0.2~0.8m/s. Too high a speed will lead to insufficient venting and cracking; too low a speed will affect output.
Common problems and solutions for Fertilizer Granules Compaction Machine
| Common Problems | Possible Causes | Solutions |
|---|---|---|
| Insufficient particle strength, easy to break | 1. Material moisture content is too low 2. Insufficient system pressure 3. Insufficient feeding amount |
1. Appropriately add a small amount of water (recommended at about 1.5%-3%) 2. Adjust the hydraulic system or tighten the spring to increase pressure 3. Increase the feeding speed to ensure sufficient material between the roll gaps |
| Equipment jamming / Motor overload | 1. Excessive feeding amount 2. Metal foreign matter is caught between the rolls 3. The roll gap is too small |
1. Reduce the feeding amount and clean up the accumulated material 2. Stop the machine for cleaning, and it is recommended to install a strong magnetic iron remover at the raw material end 3. Appropriately increase the roll gap |
| Difficult demolding (roll sticking) | 1. Material moisture content is too high 2. The ball socket design of the roll skin is unreasonable or severely worn |
1. Dry the material and control the moisture content of the raw material 2. Replace the roll skin with a suitable demolding angle, or install an anti-sticking scraper |
| Particles with "scalloped edge" or excessive flash | The lateral gap between the two rolls is too large, or the material overflows to both ends | Adjust the side baffle to make it close to the end face of the press roll; reduce the roll gap |
Technical Risk Warnings and Optimization Suggestions:
Corrosion and Wear Risks: If used for processing highly corrosive materials such as potassium chloride and urea, it is recommended that the pressure roller bearings and material contact parts be made of stainless steel or have an anti-corrosion coating. The roller skin material should be a high-chromium alloy and undergo overall quenching treatment.
Overload Protection Optimization: It is recommended to add current overload interlock protection to the control system. When the main machine current exceeds the safety threshold, the forced feeding screw should be automatically stopped to prevent the pressure roller from seizing and burning out the motor.
Double-roll press granulators, as highly efficient solid granulation equipment, are widely used in various industries. To meet different needs, the die structure, automatic control system, and screening and shaping processes can be further optimized. It is recommended to select and configure the appropriate model based on the specific properties of the raw materials and production capacity requirements, and to strengthen daily maintenance and management to promote energy conservation and consumption reduction.
For specific model selection advice or equipment integration solutions with production lines, please feel free to consult us or discuss practical case studies.
| Model | DZJ-I 1.0 | DZJ-I 2.0 | DZJ-I 3.0 | DZJ-I 4.0 |
| Capacity (t/h) | 1~1.5 | 1.5~2.5 | 2~3 | 3~4 |
| Power (Kw) | 11K | 18.5KW | 22KW | 45KW |
| Roller Dimension(mm) | Φ150×220 | Φ150×300 | Φ186×300 | Φ300×300 |
| Feed Material Size(mm) | ≦0.5mm | ≦0.5mm | ≦0.5mm | ≦0.5mm |
| Output Granules Size(mm) | Φ2.5~Φ10 | Φ2.5~Φ10 | ø2.5-ø10 | ø2.5-ø10 |
| Gearbox Model | ZLY160 | ZLY160 | ZLY180 | ZLY224 |
| Rotation Speed (r/min) | 60 | 60 | 60 | 60 |
