Circular Gyratory Screens use a low-frequency oscillatory motion that mimics artificial shaking, creating a three-dimensional, compound motion that creates a spiral diffusion path across the screen surface. This motion pattern effectively reduces material clogging and improves screening accuracy, making it particularly suitable for the fine screening of hygroscopic and agglomerated materials like citric acid. Coreal Machinery has compiled some information for your reference.
In citric acid production in the chemical industry, circular gyratory screens are a key piece of equipment for ensuring uniform particle size in the final product.
I. Core Issue Analysis: Why Do Citric Acid Particles Occur Unevenly?
After crystallization and drying, citric acid may have a wide particle size distribution. Reasons include:
- Crystallization Process Fluctuations: Poor control of the crystallizer temperature, stirring speed, and concentration can lead to varying initial crystal sizes.
- Drying Process Impacts: Particle breakage or agglomeration may occur during drying.
- Mechanical Conveying Damage: During conveying, particles may collide with each other or with the pipe wall, leading to breakage.
II. Key Parameter Optimization
1. Screen Selection
- Material: 304 stainless steel (corrosion-resistant) or polyurethane (wear-resistant) are preferred to prevent corrosion from citric acid on the equipment.
- Aperture: Select the screen according to the target particle size to ensure accurate particle grading.
- Screen Cleaning Device:
Bouncing Ball Cleaning System: Suitable for medium-sized citric acid (60-100 mesh).
Ultrasonic Cleaning System: Suitable for fine powders or materials prone to screen clogging.
Air-Brush System: Suitable for handling high-humidity or sticky materials.
2. Vibration Parameter Settings
- Frequency: 800-1500 rpm, 1200-1400 rpm is recommended for citric acid screening.
- Amplitude: 2-5 mm, 3-4 mm recommended. mm (balances screening efficiency and particle integrity)
- Screen surface inclination: 3-7° to extend material residence time
III. Equipment Structure Improvement
- Multi-layer Screen Configuration: A 2-3-layer screen design is used to achieve a grading process from coarse screening (upper layer) to fine screening (middle layer) to protective screening (lower layer).
- Feed Distributor: A rotating distributor plate is installed to evenly distribute the material across the center of the screen surface, preventing local overload.
- Sealing and Dustproof Design: A silicone seal and vacuum negative pressure system are used to prevent citric acid dust leakage.
IV. Process Operation and Maintenance
- Uniform and Stable Feeding
Use a feeder to ensure that the material flow into the Circular Gyratory Screen is stable and uniform. Unstable flow will affect product uniformity.
- Strict Environmental Control
Citric acid easily absorbs moisture, so the environment should be kept at low humidity and constant temperature. Moisture absorption by the material will destroy the screening effect and uniformity is out of the question.
- Regular Maintenance and Inspection
Regularly inspect the screen: The screen is a consumable part. Regularly check for damage, looseness, or blockage. If damaged, replace it immediately to prevent mixing of materials of different specifications.
Cleaning and Maintenance: After each use or when changing product specifications, the equipment must be thoroughly cleaned to prevent cross-contamination.
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