FBC Boiler Bed Material
FBC Boiler Bed Material
FBC (Fluidized Bed Combustion) Boiler Bed Material—also known as boiler sand or refractory bed material—is a highly engineered aggregate essential for fluidized bed boilers (FBC, including AFBC and CFBC types). Its main function is to create a stable, heat-resistant physical “bed” for thorough, efficient, and clean combustion of solid fuels such as coal, lignite, biomass, and waste.
Composition & Chemical Properties
- SiO₂ (Silica): 50–70% (commonly 60–65%)—forms the base structure for heat resistance.
- Al₂O₃ (Alumina): 30–40%—improves refractory and thermal properties, crucial for resisting high temperatures.
- Fe₂O₃ (Iron Oxide): Less than 1.5–2.5%—lower levels reduce slagging and clinker formation.
- Na₂O + K₂O (Alkalis): Less than 1%—low alkali content prevents chemical reactions and fouling.
- Other Minerals: May include trace titanium oxide (TiO₂ ≤1%) and very low moisture; sometimes contains fire clay and other refractory minerals.
Physical & Performance Properties
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Property
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Typical Range
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|---|---|
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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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Approx. 2.0g/cm³
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Fusion Temperature
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>1,300°C (often up to 1,400°C)
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Initial Deformation Temp (IDT)
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>1,300°C
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Form
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Granular or powdered, off-white/beige, screened and dust-free
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- Perfectly screened for accurate particle size distribution and minimal fines or over-sized grains.
- Exceptional resistance to thermal shock, abrasion, and chemical attack.
- No free iron particles passed through magnetic separators for purity.
- Packaged in 40–50kg HDPE/BOPP bags, 1MT jumbo bags, or supplied in bulk.
Key Benefits & Functions
- Smooth Fluidization: Size and density are engineered to ensure optimal fluid-bed movement, mixing, and heat transfer, critical for efficient combustion.
- Clinker/Slag Resistance: High purity and low iron/alkali content minimize risk of slag, clinker, or agglomeration at high temperatures.
- Compatibility: Can be tailored to specific boiler/fuel requirements by adjusting grain size and chemical profile.
- Thermal & Mechanical Stability: Withstands repeated cycles without degradation.
- Tube Protection: Reduces erosion and wear on boiler tubes, extending operational life.
- Fuel Flexibility: Supports combustion of coal, lignite, biomass, petcoke, and waste fuels in FBC systems.
Typical Applications
- FBC, CFBC, and AFBC boilers in power plants, cement, chemicals, and waste-to-energy sectors.
- Other industrial uses: Heat-resistant lining, kilns, incinerators, reactors, and ash hoppers.
Specification Summary Table
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Chemical/Physical Property
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Typical Specification
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|---|---|
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Silica (SiO₂)
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50–70%
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Alumina (Al₂O₃)
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30–40%
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Iron Oxide (Fe₂O₃)
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≤1.5–2.5%
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Alkalis (Na₂O + K₂O)
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≤1%
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Fusion/Deformation Temp
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>1,300°C (up to 1,400°C)
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Bulk Density
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950–1,100kg/m³
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Particle Size
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0.85–2.36mm (0.6–2.8mm optional)
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Selection & Economic Considerations
- Selection: Correct grain size/composition is vital—mismatched properties may cause fluidization problems or excess clinker/ash.
- Standards: Usually produced per BHEL, ASTM, IS, or BS standards and supplied with quality test certificates.
- Cost: Priced ₹1,500–₹5,500 per tone in India (varies by quality, packaging, and location).
Summary
FBC Boiler Bed Material is a high-silica, moderate-alumina, low-iron refractory aggregate, cleaned, screened, and sorted for precise grain size and purity—delivering smooth fluidization, high thermal stability, and optimal heat transfer, all of which are indispensable for the safe, clean, and efficient operation of fluidized bed boilers