1. What Is a Hot Blast Stove Gas Preheater?

A Hot Blast Stove Gas Preheater is a waste heat recovery heat exchanger installed in a hot blast stove system. It utilizes high-temperature exhaust flue gas from the hot blast stove to preheat the incoming fuel gas or combustion air before it enters the stove.

The primary purpose of the gas preheater is to recover waste heat, improve combustion efficiency, reduce fuel consumption, and lower overall energy costs, while simultaneously decreasing flue gas temperature and thermal emissions.

This equipment is widely used in iron and steel plants, especially in blast furnace hot blast stove systems.

2. Working Principle

The hot blast stove gas preheater operates based on indirect heat exchange:

1. Flue Gas Side (Hot Side)
   High-temperature flue gas (typically 600–800 °C) discharged from the hot blast stove flows through the hot side of the heat exchanger.

2. Gas / Air Side (Cold Side)
   Cold fuel gas or combustion air flows through the cold side channels or tubes.

3. Heat Exchange Process

   • Heat is transferred through tube walls, plates, or heat pipes

   • Fuel gas or air temperature rises significantly

   • Flue gas temperature drops before entering downstream dust removal or desulfurization units

The preheated gas or air then enters the hot blast stove, improving flame stability and thermal efficiency.

3. Main Functions and Advantages

4. Typical Structure

A hot blast stove gas preheater generally consists of:

• Heat Exchange Elements
  Tube bundles, finned tubes, plate packs, or heat pipes

• Casing / Shell
  Carbon steel or alloy steel with thermal insulation

• Gas and Flue Gas Inlet/Outlet Nozzles
  Flanged connections for system integration

• Expansion Compensation Structure
  To absorb thermal expansion of tubes and shell

• Soot Blowing or Cleaning System (Optional)
  Prevents ash accumulation and fouling

• External Insulation Layer
  Minimizes heat loss and protects personnel

5. Key Design Considerations

6. Typical Operating Parameters (Reference)

Actual parameters depend on fuel composition, flow rate, and operating conditions.

7. Application Areas

• Blast furnace hot blast stove systems

• Coke oven and metallurgical furnace systems

• Industrial kilns and reheating furnaces

• High-temperature waste heat recovery systems

8. Common Problems and Solutions

9. Difference from Conventional Heat Exchangers