Ceramic Fiber Furnace Lining Repair Guide: Effective Solutions for Shrinkage Cracks and Damage/Detachment

Introduction:

Ceramic fiber furnace linings operating in high-temperature environments are susceptible to issues like shrinkage cracks, damage, or detachment. Timely and effective repairs are crucial for extending the lining’s lifespan and ensuring safe production. This guide details repair solutions for various ceramic fiber furnace lining issues, helping you quickly resolve problems and restore optimal lining performance.

1. Repairing Shrinkage Cracks:

When cracks wider than 5mm appear in the ceramic fiber furnace lining, immediate repair is necessary.

• Repair Method: Use ceramic fiber blankets of the same grade for filling. When filling, ensure the blanket is pushed as deep into the crack as possible until it is fully compressed. Avoid only filling the surface, as this will lead to detachment again during operation, creating safety hazards.

2. Repairing Detached Standard Ceramic Fiber Modules:

When standard ceramic fiber modules detach, replace them with new modules of the same size.

• Repair Steps:

1. Reweld anchor studs at the original anchor positions.
2. Lay a ceramic fiber blanket backing.
3. Install the new ceramic fiber module.
4. Fill the space between two rows of modules in the non-folding compression direction with ceramic fiber blankets to compensate for shrinkage.
5. Fill larger gaps between the replaced area and surrounding unreplaced modules with ceramic fiber blankets as well.

3. Repairing Detached Irregularly Shaped Ceramic Fiber Modules:

For detached irregularly shaped ceramic fiber modules (such as corner modules or arc-shaped modules), it is recommended to use the layered ceramic fiber blanket method for repair.

• Reasons for This Method:

1. It is often difficult to find replacement parts of the same model after irregularly shaped modules detach.
2. Under long-term high-temperature conditions, the remaining attached irregularly shaped modules may also experience shrinkage and loss of elasticity. Directly replacing them with the same model could result in insufficient contact between the new and old modules, creating potential safety hazards.

• Repair Method:

1. Weld long anchor studs.
2. Lay ceramic fiber blankets layer by layer until the original lining thickness is achieved.
3. Use ceramic cups to secure the surface layer.

• Advantages of This Method: The layered method allows the ceramic fiber blanket to be cut slightly larger than the detached area, creating compression at the contact point with the remaining modules, effectively preventing gaps and further detachment due to shrinkage.

• Successful Case Study: In a petrochemical plant, detached corner modules on the cracking furnace roof and the steam superheater lifting hole of a styrene unit were successfully repaired using the layered method, with excellent operational results. (Here you can insert Figures 1-3 with captions, such as “Figure 1: Before Repair of Corner Module on Cracking Furnace Roof,” “Figure 2: Layered Repair Method in Progress,” “Figure 3: After Repair.”)

4. Important Considerations:

• High-Temperature Shrinkage: Ceramic fiber furnace linings shrink under high temperatures due to the material’s properties, caused by crystallization and grain growth at high temperatures. Shrinkage can lead to lining cracks and gaps, eventually causing damage and detachment under long-term exposure to high-temperature flame and airflow.
• Other Influencing Factors: Dimensional and quality deviations in the ceramic fiber materials, construction quality defects, and human factors can accelerate damage and detachment, shortening the service life. Therefore, high attention must be paid during installation, inspection, and maintenance.
• Repair Principles: If replacement materials of the original model can be found, repair should be carried out according to the original structure. If original model materials are unavailable, the layered ceramic fiber blanket method can be used as an alternative.

Conclusion:

This guide provides a deeper understanding of ceramic fiber furnace lining repair methods. Correct repair methods can effectively extend the lining’s service life, reduce maintenance costs, and ensure production safety.