Why Industrial Exhaust Heat Recovery Heat Exchangers Are Needed

Why Industrial Exhaust Heat Recovery Heat Exchangers Are Needed

Industrial exhaust heat recovery heat exchangers are energy-saving devices installed in emission systems of industrial furnaces, boilers, drying equipment, chemical processes, etc. They recover the sensible heat and partial latent heat carried by exhaust gases, reusing this heat in industrial production processes.

Why is it needed?

Industrial exhaust gases typically operate at high temperatures (200°C to 1000°C or higher). Direct discharge represents a massive waste of valuable thermal energy. Recovering this energy:

- Directly saves fuel: Reduces production energy costs.

- Lowers emissions: Decreases carbon emissions (CO₂) and pollutants (e.g., NOx, SOx) per unit of product.

- Enhances overall energy efficiency: Optimizes process flows and improves energy utilization.

Main Types and Working Principles

Finned Tube Heat Exchanger

Structure: Fins expanded onto the outer wall of the base tube significantly increase the heat transfer area on the exhaust gas side.

Advantages: Compact structure, high heat transfer efficiency, cost-effective.

Applications: Most commonly used for preheating combustion air (as an “air preheater”) or heating water/thermal oil.

Plate Heat Exchanger

Structure: Constructed from stacked thin metal plates forming alternating channels for cold and hot fluids.

Advantages: Extremely high heat transfer coefficient, compact design, easy disassembly and cleaning.

Disadvantages: Limited pressure tolerance, sensitive to dust content in exhaust gases, typically used for low-to-medium temperature, clean gases.

Applications: Heat exchange between exhaust gas and gas, or exhaust gas and liquid (e.g., water).

Heat Pipe Heat Exchanger

Structure: Consists of sealed vacuum tubes filled with working fluid. The evaporation section absorbs heat from exhaust gas, vaporizing the fluid which rises to the condensation section. Here, it releases heat to the cold medium before condensing and returning, repeating the cycle.

Advantages: Extremely high heat transfer efficiency, excellent isothermal performance, complete isolation of hot and cold fluids, safe and reliable operation, with individual heat pipe failure not affecting overall system function.

Applications: Particularly suitable for corrosive or easily clogged exhaust gas conditions, and scenarios requiring strict isolation of hot and cold fluids.

Primary Application Fields and Heat Recovery Uses

Metallurgy: Rolling mill heating furnaces, annealing furnaces, soaking furnaces -> Preheating combustion air and gas.

Building Materials: Cement kilns, glass melting furnaces -> Preheating combustion air, waste heat power generation.

Chemical Industry: Cracking furnaces, reforming furnaces, drying equipment -> Preheating process feedstock, steam generation.

Machinery Manufacturing: Foundry heat treatment furnaces, coating drying ovens -> Preheating combustion air, workshop heating.

Power Generation: Gas turbine exhaust -> Waste heat boiler power generation (combined cycle).

Waste Incineration: Incinerator flue gas -> Steam production for power generation or heating.