AFBC Boiler Bed Material
AFBC Boiler Bed Material
AFBC Boiler Bed Material also known as refractory bed material or boiler sand—is a specialized, engineered product used in Atmospheric Fluidized Bed Combustion (AFBC) boilers. Its main function is to form the fluidized bed in the boiler’s combustion chamber, enabling efficient, uniform fuel burning and heat transfer. Here is comprehensive information based on current industrial standards and supplier details:
Composition
- Primary constituents: High-purity silica (SiO₂, typically 60–70%), moderate alumina (Al₂O₃, 30–40%), and very low iron (Fe₂O₃ < 1.5–2.5%). Alkalies (Na₂O + K₂O) are kept under 1% to minimize slagging and clinker formation.
- Other materials: Some variants use crushed or blended refractory minerals (like fireclay-based or ceramic aggregate types) for enhanced heat resistance and fluidization.
- Color and texture: Beige or off-white, granular or powdered, with a highly dense texture and minimal dust.
Key Physical Properties
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Property
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Typical Range
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Particle Size
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0.85–2.36mm (sometimes up to 2.8mm)
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Bulk Density
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950–1,100kg/m³
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Particle Density
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~2.00g/cm³
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Fusion Temp
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>1,300°C (often up to 1,400°C)
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Moisture
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As low as possible, highly dried
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Abrasion Resistance
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High
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Packaging
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40–50kg HDPE or BOPP bags, 1MT jumbo bags, bulk
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Performance and Benefits
- Perfect Fluidization: High purity and consistent particle size ensure smooth bed movement, preventing agglomeration or clinker formation and reducing boiler downtime.
- Thermal Stability: Engineered for high resistance to thermal shock and abrasion, supporting stable, uniform heat distribution.
- Boiler Tube Protection: Reduces erosion and wear on boiler tubes, increasing component life and lowering maintenance.
- Fuel Flexibility: Adapts well to diverse fuels (coal, biomass, lignite, petcoke, etc.), supporting efficient combustion and emission reduction.
- Cost-effectiveness: Low consumption and high productivity due to extended particle life.
Application & Usage
- Industries: Power plants, cement plants, and steam/power generation units using AFBC boilers.
- Method: The bed material is charged into the AFBC boiler bed, where air is passed through from the bottom, creating a fluidized state that efficiently combusts the fuel.
- Customization: Sizing, chemical specs, and packaging can be tailored as per specific boiler/fuel requirements.
Selection Criteria
- Compatibility: Must fit the specific fuel (coal, biomass, etc.) and boiler design; inappropriate grain size or impurity can cause operational issues.
- Standards: Material is often produced per technical standards (e.g., BHEL, ASTM, BS) and quality-tested before dispatch.
Price Range
- Prices typically range from ₹1,500 to ₹5,500 per tonne in India, depending on grade, packaging, and location.
Summary
AFBC boiler bed material is a high-alumina, low-iron, refractory aggregate blend, screened and processed for granularity, purity, and heat duty—making it central for smooth, efficient, and economical AFBC boiler operation and maintenance.