Industrial refractory lining is not a simple combination of materials, but a system-level engineering solution driven by functional requirements. In modern furnace lining and kiln lining design, structural configuration, material selection, and performance verification must be accurately matched to real operating conditions.
1. Structure Analysis: Three Functional Layers in Practice
1.1 Hot Face Layer: Two Main Technical Paths
Brick-based solution: Suitable for high-temperature, high-abrasion, and mechanically defined areas.
- Advantages: Precise dimensions, high-temperature stability, and easier quality control
- Key Selection: Accurate calculation of brick types and expansion joint layout
- Validation: Thermal shock testing (≥20 cycles) and erosion resistance tests
Castable-based solution: Suitable for complex geometries or areas requiring monolithic lining.
- Advantages: Seamless construction, excellent thermal shock resistance, flexible design
- Key Selection: Focus on castable workability and firing/drying schedule
- Validation: Same as above
1.2 Insulating Layer: Multi-Material Applications
Brick/Board structures: Lightweight insulating bricks, ceramic fiber boards
- Support required compressive strength
- Ceramic fiber boards are preferred in thermally sensitive zones
Castable structures: Lightweight insulating castables, plastic refractories
- Form monolithic insulation with fewer joints
- Thickness can be precisely controlled to fit complex geometries
Important Note: In some two-layer designs, insulation can be fully handled by high-strength lightweight castables or fiber modules, omitting a separate outer insulation layer.
1.3 Outer Insulation Layer: Advanced Thermal Protection
Main materials: Ceramic fiber blankets/modules, nano-microporous boards
Ceramic fiber: cost-effective, widely used
Nano-microporous boards: extreme insulation for space-limited or ultra-energy-saving scenarios
Integration: Can be fixed directly to the shell or combined with the insulating layer for enhanced performance.
2. Material Selection and Verification: Matching Function with Performance
Core principles:
- Temperature gradient matching: Each layer’s maximum service temperature must exceed transmitted temperature from inner layers
- Mechanical compatibility: Thermal expansion coefficients should be coordinated, and expansion joints designed systematically
- Construction feasibility: Multi-layer structures require evaluation of installation sequence and quality checkpoints
Typical errors and optimization:
- Mistake: Brick structure without sufficient expansion joints in rapid temperature zones → lining cracks
- Optimization: Use thermal-shock-resistant castables with flexible buffer layers
Kerui Refractory verification:
- Material-level: GB/T standard testing reports for each batch
- System-level: Thermal modeling calculates interface temperatures and stress distribution
- Application-level: Historical field data predicts service life under similar conditions
3. Engineering Practice: Key Controls from Design to Construction
Critical engineering details:
- Anchoring system: Ceramic anchors for high-temperature zones, alloy steel for mid-low temperature zones
- Interface treatment: Buffer or slip layers between different materials
- Firing schedule: Stepwise, slow heating for castable-based linings
Kerui Refractory’s integrated approach:
- Design verification: Real-data-based thermo-mechanical analysis
- Material verification: Full laboratory testing and in-situ mock-ups
- Construction verification: Checklists for critical process points
- Acceptance verification: Infrared scanning to ensure no thermal defects
Kerui Refractory: Full-Process Lining Solutions
Whether choosing brick-based or castable-based structures, a reliable kiln lining system depends on accurate thermal calculations, verified material performance, and standardized engineering practices. Kerui Refractory provides end-to-end solutions, ensuring that each layer of the “sandwich” lining is validated in design and performs optimally in operation.
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