Pneumatic conveying systems are generally divided into two main types:
1. Dilute Phase Conveying
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Working Principle:
Material is suspended and transported within a high-velocity airstream. -
Key Parameters:
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Air Velocity: High (18–30 m/s)
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Pressure: Low (0.02–0.09 MPa)
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Distance: Best suited for short distances (≤300 meters)
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Dust Concentration: Suitable for low to medium concentrations (1–10 kg/m³)
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Advantages:
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Lower initial investment
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Simpler maintenance
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Broad material compatibility (suitable for nearly all bulk solids)
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Disadvantages:
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High velocity may lead to material degradation, excessive dust generation, and increased pipe wear
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Higher energy consumption, especially in short-distance or small-batch applications
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2. Dense Phase Conveying
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Working Principle:
Material is conveyed in a plug flow or slug form, not suspended in the air stream. -
Key Parameters:
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Air Velocity: Low (2–10 m/s)
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Pressure: High (0.3–0.7 MPa)
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Solid-to-Gas Ratio: High (≥25)
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Advantages:
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Reduced pipeline wear and minimal material degradation—ideal for fragile materials (e.g., lithium battery powders)
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More energy-efficient for long-distance conveying
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Disadvantages:
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Requires systems capable of delivering high pressure
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Higher installation cost due to larger pipe diameters
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How to Choose Between Dilute and Dense Phase Conveying?
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Material Characteristics:
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Use dilute phase for non-abrasive, fine particles (e.g., plastics, food ingredients).
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Use dense phase for abrasive, fragile, or sticky materials (e.g., cement, fly ash).
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Distance and Pressure Requirements:
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Dilute phase is preferred for conveying distances under 300 meters.
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Dense phase is ideal for distances beyond 300 meters, provided adequate pressure is available.
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Economic Considerations:
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Balance the lower initial cost and simpler maintenance of dilute phase systems against the long-term energy savings and reduced material damage offered by dense phase systems.
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