Wear-Resistant Castables for CFB Boilers: Selection & Use

Wear-Resistant Castables for CFB Boilers: Selection and Use

1. CFB Wear Conditions

Circulating fluidized bed (CFB) boilers entrain high-temperature ash particles into the cyclone separator, where gas-solid two-phase flow continuously scours the cyclone barrel, cone, loop seal and flue elbows. Wear intensity relates to gas velocity, particle concentration and hardness, and flow direction—the leading cause of CFB lining failure. The separator zone also faces temperature cycling and local alkali attack, so selection must balance wear, temperature and thermal-shock resistance.

2. Wear Mechanism and Material Selection

Abrasion resistance depends on hardness, density and bond strength. Common wear-resistant castables use high-alumina bauxite or brown corundum aggregate with Al₂O₃≥70% and CCS≥90MPa, resisting particle scouring with a dense matrix. For the heaviest wear in cyclone barrels and cones, recommend SiC wear-resistant castable (SiC≥50%)—SiC is extremely hard with high thermal conductivity, forming a self-protecting slag coating, with superior wear and thermal-shock performance. Design the insulation layer and wear working layer separately, with working-layer thickness based on wear allowance.

3. Installation Essentials: Success Lies in Details

Installation quality directly decides wear lining life. Control water ratio at the datasheet lower limit—excess water is the main cause of lower strength and wear resistance; anchor layout density and weld quality must follow design with heat-resistant steel anchors in hot zones; vibrate fully for dense bonding with anchors and substrate; bake out strictly per curve to avoid early spalling. For irregular zones like cyclone cones, use precast blocks—factory-cured, crane-installed, more stable quality.

4. Operation, Maintenance and Life Management

Monitor flue gas velocity and separator differential pressure—abnormal pressure often indicates wear or ash buildup; at maintenance, focus on barrel wear thickness and thinning of loop seals and elbows, recording wear data to optimize grade and thickness design. Hot-gun repair or precast replacement handles severe local wear. Plan maintenance cycles to avoid a passive "repair after wearing through" situation.

5. Conclusion

The core of CFB wear linings is "right grade, right details, right operation": SiC wear-resistant castable for the heaviest wear zones, high-alumina wear-resistant for general wear areas, strict water control and full vibration in installation, and pressure/wear monitoring in operation. Henan Songrui New Refractory Materials Co., Ltd. supplies the full CFB wear castable and precast range with site survey and selection services.