Refractories for waste incinerators

Types of waste incinerators and refractory requirements

The main types of waste incinerators:

  1. Pusher furnace (lattice type)

  2. Fluidised bed (fluidised bed) incinerators

  3. Converter

Advantages of incineration:

  • Complete destruction of pathogens (bacteria and viruses)

  • Energy recovery

Special requirements for refractory materials:

  1. Volume stability at high temperatures

  2. High strength and wear resistance

  3. Heat resistance (thermal shock resistance)

  4. Chemical resistance to aggressive media

  5. Thermal insulation properties

Current trends:

  • 75% share of amorphous refractories (up 20% in the last decade)

  • Advantages of precast parts:

    • Easy installation in complex structures

    • Improved integrity and airtightness of the lining

    • Energy-efficient production (up to 30% compared to bricks)

Usage characteristics:

  • Combustion temperature: 850-1200°C (lower than metallurgical processes)

  • Harmful components:

    • Unburnt organic residues

    • Heavy metals (lead, cadmium, mercury)

    • Dioxins (PCDD/PCDF)

Silicon carbide (SiC) is a promising material:

  • Excellent corrosion resistance (2-3 times higher than Al₂O₃-SiO₂ systems)

  • Key solution:

    • Extend the service life of the ash zone

    • Prevent secondary pollution from slag

    • Control of fly ash corrosion

Temperature conditions and material classification

  • Operating temperature: ≤1200°C

  • Material type:

    • Shaped refractory

    • Unshaped refractory material

Mainly used refractory materials

Material Ingredient content Application
Bricks – Clay brick (Al₂O₃ 30-45%) Area ≤1000°C
– High Alumina Bricks (Al₂O₃ ≥60%) High temperature area
– Silicon Carbide Bricks (SiC ≥90%) Severe erosion area
Castable – Clay and high alumina castables For maintenance
– SiC-castables Pipe protection

Furnace zone selection criteria

  • Slag discharge zone (1000-1300°C):

    • Best choice: Silicon carbide bricks (advantages):

      • Slag resistance (slag adhesion coefficient < 0.15)

      • 2-3 times longer service life than Al₂O₃-SiO₂ systems

  • Protects pipes from corrosion:

    • Solution: Silicon Carbide Castables (Properties)

      • Resistant to HCl/Cl₂ (weight loss <1.5% after 100 cycles)

      • Limitations: difficult to remove (compressive strength ≥ 80 MPa)