Views: 0 Author: Site Editor Publish Time: 2026-02-02 Origin: Site
In ironmaking plants, hot blast stoves are among the largest sources of high-temperature flue gas. A blast furnace hot blast stove flue gas waste heat recovery heat exchanger is engineered to capture this otherwise lost thermal energy and reuse it for air preheating, fuel gas heating, boiler feedwater heating, or low-pressure steam generation. This technology plays a critical role in reducing fuel consumption, lowering CO₂ emissions, and improving overall plant energy efficiency.
Application: Waste heat recovery from hot blast stove flue gas
Industry: Iron & steel / blast furnace ironmaking
Operating mode: Continuous, high-temperature industrial duty
Installation location: Downstream of hot blast stove combustion chamber, upstream of stack or dust removal system
Typical flue gas temperatures at the stove outlet range from 250–400 °C, with significant recoverable sensible heat.
Hot blast stove flue gas presents several design challenges:
High temperature: Continuous exposure to elevated gas temperatures
Large gas volume: High Nm³/h flow rates
Dust loading: Fine particulates from combustion and refractory erosion
Corrosive components: SOx, NOx, and moisture under certain operating conditions
The heat exchanger must therefore combine high thermal efficiency, low pressure drop, and excellent resistance to fouling and thermal stress.
Depending on process requirements and site constraints, several exchanger concepts are commonly applied:
Suitable for dusty, high-temperature flue gas
No dense fins to avoid ash and dust clogging
Easy mechanical or online cleaning
Long service life in harsh environments
Compact footprint
High heat transfer efficiency
Fully welded construction for high temperature and pressure resistance
Recovers flue gas heat to preheat combustion air or blast air
Improves stove thermal efficiency directly
Often designed as a crossflow or counterflow tubular exchanger4. Typical System Configuration
A standard waste heat recovery system includes:
Hot blast stove flue gas outlet
High-temperature waste heat recovery heat exchanger
Dust collection or filtration system
Induced draft fan
Stack
Recovered heat can be utilized for:
Combustion air preheating
BF gas or coke oven gas preheating
Boiler feedwater heating
Low-pressure steam generation for plant use
Material selection is critical for long-term reliability:
Heat transfer tubes: Carbon steel, low-alloy steel, or stainless steel (depending on temperature and corrosion risk)
Headers / manifolds: Carbon steel or alloy steel
Casing: Carbon steel with high-temperature insulation
Expansion joints: Metallic or fabric compensators to absorb thermal expansion
All designs account for differential thermal expansion between gas and fluid sides.
Typical design considerations include:
Flue gas inlet temperature: 250–400 °C (higher possible during transient conditions)
Flue gas pressure drop: Optimized to minimize impact on stove draft
Design pressure (fluid side): According to downstream system (water, steam, or air)
Fouling factor: Increased allowance due to dust content
Thermal expansion: Floating or flexible structure to prevent stress failure
10–25% reduction in fuel consumption for hot blast stoves
Lower CO₂ and NOx emissions
Improved overall blast furnace energy balance
Short payback period due to high energy recovery potential
Enhanced sustainability and compliance with energy efficiency regulations
A blast furnace hot blast stove flue gas waste heat recovery heat exchanger is a proven energy-saving solution for modern ironmaking plants. By efficiently recovering high-temperature flue gas heat and reusing it within the process, steel producers can significantly reduce operating costs while improving environmental performance.
