Application of High-Temperature Wood Chip Indirect Hot Air Furnace in Silica Industry

I. Project Background

Precipitated silica is widely used in rubber, tire, and coating industries. As a white powder material, it requires extremely clean heat sources during production.

In the drying process, high-temperature clean hot air at 400–500°C is typically required. Conventional direct-fired hot air furnaces can meet the temperature requirement, but often carry dust and flue gas impurities, which may contaminate the product.

Therefore, achieving both high temperature and clean air supply is a key challenge in the silica industry.

II. Solution

To meet these requirements, a biomass high-temperature indirect hot air furnace is adopted, combining a wood chip burner with a high-temperature resistant heat exchange system.

The process is as follows:

• Wood chips are combusted in the burner to generate high-temperature flue gas
• The flue gas enters a high-temperature heat exchanger
• Cold air is heated to 400–500°C through indirect heat exchange
• Clean and high-temperature hot air is supplied to the drying system

With heat-resistant materials and optimized design, the system ensures stable operation under high-temperature conditions while maintaining complete separation between flue gas and hot air.

III. Advantages

1. Clean High-Temperature Air Output
Indirect heating eliminates contamination, ideal for silica production.

2. Meets High-Temperature Requirements
Stable hot air supply at 400–500°C.

3. Reduced Energy Costs
Biomass fuel significantly lowers operating costs compared to gas.

4. High-Temperature Resistance and Stability
Designed for continuous operation under high-temperature conditions.

5. Eco-friendly and Energy-efficient
Supports sustainable and low-carbon manufacturing.

IV. Project Results

This high-temperature indirect hot air furnace has been successfully applied in the silica industry, with positive feedback from clients:

• Stable high-temperature air supply
• Clean hot air with no contamination
• Improved product quality
• Significant energy cost savings (around 30% vs. natural gas)
• Reliable operation and easy maintenance

It is now considered an ideal solution for clean, high-temperature heating in the silica industry.