Four Power Boiler Types Covered on This Page
Circulating Fluidized Bed Boiler (CFB)
Widely used for low-grade coal and biomass co-firing. Key refractory areas: combustion chamber, cyclone separator, loop seal, and return leg.
Pulverized Coal Boiler
Dominant technology for large utility boilers. Critical zones: burner zone, furnace walls, slag tap, and nose arch.
Waste-to-Energy Boiler (MSW Incinerator)
Municipal solid waste combustion with severe chlorine and alkali corrosion. Requires high-density SiC and chrome-alumina refractories.
Biomass Power Boiler
Burning wood chips, straw, and agricultural residues. High risk of alkali-induced slagging and fouling. Specialized alumina-silica materials.
Power Boiler Diagrams and Refractory Area Labels
Furnace Water-Wall Zone: Low Cement Castable / Abrasion Resistant SiC Castable
Fluidized Bed Area: Low Cement Castable / High Alumina Castable
Cyclone Separator: High Alumina Castable / Corundum Castable
Loop Seal / Standpipe: Low Cement Castable / Corundum-Mullite Castable
Refractories for CFB Boilers
CFB boilers require high abrasion resistance in the dense bed and cyclone. High thermal shock resistance is crucial in start‑up zones.
- Furnace Water-Wall Area: Low Cement High Alumina Castable / Abrasion Resistant SiC Castable
- Fluidized Bed Area: Ultra Low Cement Castable / High Alumina Castable / Silicon Carbide Castable
- Cyclone Separator: High Alumina Castable / Corundum Castable / Silicon Carbide Castable / Corundum-Mullite Brick
- Loop Seal / Standpipe: Low Cement High Alumina Castable / Corundum-Mullite Castable / Wear Resistant High Alumina Brick
Radiant Zone: Low Cement High Alumina Castable
Burner Throat Area: High Alumina Castable / Silicon Carbide Castablec
Slag Hopper: High Alumina Castable
Bottom Ash Outlet & Slag Discharge Area: Abrasion Resistant Castable
Refractories for Pulverized Coal Boilers
Main challenges: slagging, thermal shock, and ash corrosion. Burner quarls require high thermal shock resistance.
- Radiant Zone: Low Cement High Alumina Castable / Abrasion Resistant High Alumina Castable
- Burner Throat Area: High Alumina Castable / Silicon Carbide Castable
- Slag Hopper: High Alumina Castable / SiC Castable / Abrasion Resistant Castable
- Bottom Ash Outlet & Slag Discharge Area: Abrasion Resistant Castable / Silicon Carbide Castable
Main Combustion Chamber Side Wall: High Alumina Castable / Low Cement Castable
Furnace Roof / Arch Area: High Alumina Castable / Mullite Castable
Grate Side Wall & Slag Discharge Area: Abrasion Resistant Castable / High Alumina Castable
Secondary Combustion Zone: High Alumina Castable / Mullite Castable
Refractories for Waste-to-Energy Boilers
Severe chlorine, sulfur and alkali attack. High-density low-porosity materials are essential for corrosion resistance.
- Main Combustion Chamber Side Wall: High Alumina Castable / Low Cement Castable / Silicon Carbide Castable
- Furnace Roof / Arch Area: High Alumina Castable / Mullite Castable / Corundum-Mullite Castable
- Grate Side Wall & Slag Discharge Area: Abrasion Resistant Castable / High Alumina Castable / Silicon Carbide Castable
- Secondary Combustion Zone: High Alumina Castable / Mullite Castable / Low Cement High Alumina Castable
Furnace Wall Area: High Alumina Castable / Low Cement Castable
Grate Side Plates & Bottom Area: Abrasion Resistant Castable / High Alumina Castable
Convective Tube Bundle Zone: High Alumina Castable
Rear Arch & Burnout Chamber: Mullite Castable / High Alumina Castable
Refractories for Biomass Power Boilers
High alkali content (K, Na) causes severe fouling. Refractories must resist alkali attack and chlorine corrosion.
- Furnace Wall Area: High Alumina Castable / Low Cement Castable
- Grate Side Plates & Bottom Area: Abrasion Resistant Castable / High Alumina Castable
- Convective Tube Bundle Zone: High Alumina Castable / Mullite Castable
- Rear Arch & Burnout Chamber: Mullite Castable / High Alumina Castable
Power Boiler Refractory Selection Table
| Boiler Type / Zone | Operating Conditions | Common Materials | Recommended Materials |
|---|---|---|---|
| CFB – Furnace Water-Wall / Fluidized Bed Area | High temperature, severe abrasion, particle impact | Low Cement High Alumina Castable | Silicon Carbide Castable |
| CFB – Cyclone Separator/td> | High velocity erosion, continuous solid circulation | High Alumina Castable | Abrasion Resistant SiC Castable |
| Pulverized coal – Radiant Zone / Furnace Water-Wall Area | High temperature radiation, thermal cycling, gas erosion | High Alumina Castable | Abrasion Resistant High Alumina Castable |
| Pulverized coal – Burner Throat Area | High flame temperature, high-speed coal particle impact, thermal shock | High Alumina Castable | Silicon Carbide Castable |
| Waste incinerator – Main Combustion Chamber | High temperature, slag attack, chemical corrosion | High Alumina Castable | Silicon Carbide Castable |
| Waste incinerator – Grate & Slag Discharge Area | Mechanical wear, ash erosion, thermal shock | Abrasion Resistant Castable | Silicon Carbide Castable |
| Biomass boiler – Furnace Wall / Combustion Zone | High temperature, ash corrosion, particle erosion | High Alumina Castable | Silicon Carbide Castable |
| Biomass boiler – Grate Area | Mechanical wear, thermal cycling, ash erosion | Abrasion Resistant Castable | SiC Reinforced Castable |
Common Refractory Products for Power Boilers
Power Boiler Refractory FAQs
What refractory is best for CFB boiler cyclones to resist abrasion?
High‑alumina brick with 75–85% Al₂O₃ or andalusite brick is commonly used. For severe wear, SiC castable or nitride‑bonded SiC brick provides outstanding abrasion resistance.
How to prevent slagging in pulverized coal boiler burner zones?
Use low‑porosity mullite or SiC castable with smooth surface. Proper burner design and coal ash chemistry control are also key factors.
Which material resists chlorine corrosion in waste incinerators?
Chrome‑alumina brick (Cr₂O₃ content 10–25%) is the standard solution. For less severe areas, high‑density andalusite or SiC brick can also perform well.
What is the main cause of refractory failure in biomass boilers?
Alkali (potassium/sodium) attack leads to chemical corrosion and spalling. Use high‑alumina materials with low alkali content and anti‑alkali additives. Regular coating removal also helps.
Can the same refractory be used for CFB and pulverized coal boilers?
No. CFB requires extreme abrasion resistance (SiC, high‑alumina), while pulverized coal boilers focus on slag resistance and thermal shock. Material selection should be zone‑specific.
