Design and Materials of Regenerator Checker Blocks for Glass Furnaces

Regenerator checker blocks (packings) are a critical component of regenerators, as their design directly impacts:
– Service life
– Heat accumulation efficiency
– Temperature regime stability

Regenerator Structure and Operating Principle
In vertical regenerators of glass furnaces:
1. Lower section:
– Air and gas channels
– Grate bars made of refractory materials
2. Upper section:
– Checker block system
– Refractory partition wall between air and gas chambers (increased thickness to prevent burn-through)
3. Thermal insulation:
– Special insulating bricks to minimize heat loss

Refractory Selection for Regenerators
Primary material systems:
– MgO-Al₂O₃, MgO-Cr₂O₃, MgO-SiO₂ series:
– Magnesia bricks
– Magnesia-chrome bricks
– Forsterite bricks
– High-alumina bricks (for specific zones)

Checker Block Structure Types:
1. Siemens structure:
– Easy to clean but with limited heat exchange area
2. Ritter structure (obsolete):
– Large surface area but prone to clogging
3. Continuous channels:
– Uniform gas distribution but lower efficiency
4. Basket weave structure:
– Improved version with high stability
5. Cross-shaped AZS blocks:
– Superior corrosion resistance (7-8 year service life)
6. Cylindrical blocks:
– Wall thickness up to 40 mm, enhanced thermal conductivity

Design Criteria
1. Thermal resistance (withstands up to 1580°C in upper zones)
2. Chemical resistance to alkaline vapors and volatile compounds
3. Optimal heat exchange surface area

Material Zoning:
– Upper zone (>1400°C):
– Zirconia bricks or 98% MgO (to resist material buildup)
– Middle zone (800-1000°C):
– Direct-bonded magnesia-chrome bricks (DMC-12)
– Lower zone (<800°C):
– Dense fireclay bricks (DN-12/15)

Key Notes:
– Magnesia-chrome bricks are prohibited in gas regenerators due to degradation risk in reducing atmospheres.
– Modern cylindrical/cross-shaped blocks improve efficiency by 15% compared to traditional designs.

Structural Optimization
– Transition between grate bars and cylindrical blocks should include a 1-meter vertical section with Siemens-style masonry for even gas distribution.
– Material combinations (e.g., magnesia-forsterite bricks in middle zones) extend overall system longevity.

**Efficiency** is measured by heat exchange area: larger surface → higher regenerator performance.

*Note: Current environmental regulations restrict chromium-containing materials—MgO-ZrO₂ alternatives are preferred.*