Corundum-mullite honeycomb ceramic heat storage body (sector-shaped composite brick)

# Corundum-Mullite Honeycomb Ceramic Heat Storage Unit (Sector-Shaped Composite Brick): A Pioneer in Energy Conservation for Industrial Furnaces

In industrial furnaces across sectors such as steel, chemicals, and building materials, high-temperature flue-gas waste-heat recovery and high-efficiency combustion technologies are pivotal in reducing energy consumption and minimizing environmental pollution. As a key component of regenerative high-temperature air combustion (HTAC) technology, the corundum–mullite honeycomb ceramic heat-storage element—specifically the sector-shaped modular brick—has, thanks to its unique material properties and innovative structural design, become the “heart” driving the efficiency upgrade of industrial furnaces. This paper analyzes the core value of this innovative product from four perspectives: material characteristics, structural advantages, application scenarios, and technological breakthroughs.

## I. Material Properties: The Perfect Balance of High-Temperature Resistance and Thermal Shock Resistance

Corundum–mullite honeycomb ceramic heat-storage bodies are primarily composed of alumina (corundum) and silica (mullite), with a composite ceramic structure formed through nanoscale particle sintering. Their core advantages lie in three key aspects:

1. **High-Temperature Resistance**: The mullite crystalline phase endows the material with a temperature resistance of 1,400–1,700°C. When combined with the addition of 15%–25% alumina fine powder, the load-softening temperature is increased to above 1,650°C, enabling long-term stable operation in extreme high-temperature environments such as steel heating furnaces and glass melting kilns.

2. **Thermal Shock Resistance**: By controlling the grain size within the 5–10 μm range, the material achieves a thermal expansion coefficient as low as 2.5 × 10⁻⁶/°C. Following 1,100°C thermal cycling tests, it withstands more than 20 thermal shock cycles, effectively addressing the cracking issues commonly encountered in traditional refractory bricks due to rapid heating and cooling.

3. **Chemical Stability**: The surface is coated with a Cr₂O₃ corrosion-resistant layer, exhibiting an annual mass loss rate of less than 0.1% in a 5,000 ppm SO₂ environment. This coating effectively resists the corrosive effects of sulfur- and chlorine-containing flue gases, ensuring a service life of over 8 years—on par with international counterparts.

## II. Structural Innovation: Biomimetic Design of Fan-Shaped Composite Bricks

Traditional honeycomb ceramic heat storage units typically feature square or circular flow channels, whereas fan-shaped modular bricks achieve three major breakthroughs through a modular design:

1. **Maximized Space Utilization**: The concentric annular ring is divided into 6 to 12 sector-shaped bricks, with the curved edges of each brick precisely interlocking with those of its neighbors to form a seamless, dead-zone-free sealed structure. Taking a 2-meter-diameter annular furnace chamber as an example, this sectoral brick assembly reduces installation gaps by 5%, increasing the heat-transfer area per unit volume to 2,200 m²/m³—three times higher than that of conventional spherical heat-storage elements.

2. **Optimization of Airflow Uniformity**: The tapered aperture design of the fan-shaped bricks—8 mm at the inlet and 6 mm at the outlet—promotes laminar flow of flue gas and air within the channels, reducing pressure drop to 0.8 kPa, a 40% reduction compared with square channels, thereby ensuring that furnace temperature fluctuations are maintained within ±5°C.

3. **Enhanced Maintenance Convenience**: The modular design enables rapid replacement of individual refractory bricks; field trials at a steel plant demonstrate that replacing a single sectoral brick takes only 15 minutes, reducing furnace downtime by 80% compared with full-replacement of the heat-storage unit and lowering annual maintenance costs by RMB 1.2 million.

## III. Application Scenarios: Benchmark Cases for Energy Efficiency Upgrades Across Multiple Industries

1. **Heating Furnaces in the Steel Industry**: At a certain hot-rolling steel plant, after retrofitting conventional heat-storage spheres with corundum–mullite sector-shaped composite bricks, flue-gas outlet temperature was reduced from 850°C to 140°C, air preheating temperature was increased to 820°C, and specific energy consumption per ton of steel decreased by 40 kg of standard coal, resulting in annual natural-gas cost savings exceeding RMB 8 million.

2. **Glass Melting Furnace**: By strategically layering fan-shaped refractory bricks—using high-temperature-resistant grades in the upper layer and fast-heat-conducting grades in the lower layer—a certain float glass production line reduced furnace temperature fluctuations from ±15°C to ±5°C, increased the yield of superior-quality products from 82% to 93%, and achieved an annual output value increase of more than RMB 10 million.

3. **Petrochemical Cracking Furnaces**: After the adoption of sectoral composite bricks in ethylene cracking furnaces, NOx emissions were reduced from 180 ppm to 90 ppm, and fuel consumption decreased by 28%, thereby meeting the European Union’s Best Available Techniques (BAT) standards.

## IV. Technological Breakthroughs: End-to-End Innovation from Materials to Systems

1. **Catalytic Combustion Technology**: A platinum-based catalyst is loaded onto the brick surface, enabling catalytic combustion of CO and hydrocarbon compounds at a low temperature of 600°C. This increases the waste heat recovery rate to 98%, an improvement of 15 percentage points over conventional technologies.

2. **Intelligent Dust-Removal System**: Integrates a differential-pressure sensor with an ultrasonic dust-removal unit. When the pressure drop across the filter channels exceeds 1.5 kPa, the system automatically activates high-frequency vibrations at 20–40 kHz to dislodge and remove particles larger than 50 μm, ensuring long-term, high-efficiency operation.

3. **Customized Production via 3D Printing**: Utilizing selective laser melting (SLM) technology, custom-shaped fan-shaped bricks can be precisely printed to match the furnace chamber dimensions, with pore-channel dimensional accuracy reaching ±0.05 mm—three times higher than that achieved with conventional extrusion processes—thereby reducing heat loss caused by installation errors.

## Conclusion: The “Powerhouse” of Green Industry

Corundum–mullite honeycomb ceramic heat-storage elements (sector-shaped composite bricks) have achieved a leap in industrial furnace thermal efficiency from 60% to 75% through the deep integration of materials science and structural engineering. Driven by the “dual carbon” goals, this technology has expanded beyond traditional sectors such as steel and glass to emerging applications like hydrogen-based smelting and carbon capture. According to statistics, the domestic market for regenerative combustion technology is projected to exceed RMB 20 billion in 2025, with sector-shaped composite bricks accounting for more than 40% of the market and thus becoming one of the core pieces of equipment driving the green transformation of industry. Looking ahead, with the development of zirconia-toughened mullite,