AMETECH | In waste heat recovery projects, how should heat exchangers be selected?

Release Date:

2026-06-18

Author:

In industrial enterprise energy management systems, waste heat recovery is a key technological approach for improving energy efficiency and reducing production costs. As the core component of waste heat recovery systems, the performance compatibility of heat exchangers directly determines the economic viability and reliability of the recovery process.

Waste heat recovery

What are the main types of industrial waste heat?

Setting aside complex theoretical classifications, from an engineering‑practice perspective, waste heat in industrial settings can be categorized into three types based on the form of the heat transfer medium:

Waste heat type	Typical source	Temperature range	Key Features
High-temperature flue gas	Boiler flue gas, kiln exhaust gases, and heating furnace flue gas	200-600℃	High dust content and corrosive risk
Medium-temperature liquid	Process cooling water, equipment circulating water, and condensate	40-150℃	The medium is relatively clean and easy to recycle.
Low-temperature exhaust steam	Flash steam, low-pressure vent gas, and dry tail gas	<100℃	It has a high latent heat, but the technical challenges are considerable.

The requirements for heat exchangers vary significantly among the three categories of waste heat; these will be discussed individually below.

Flue Gas Waste Heat Recovery: Corrosion Resistance and Ash Removal Are Key

The two major challenges in flue gas heat exchange are Dust accumulation and Corrosion . Accumulated ash increases thermal resistance and reduces efficiency; low-temperature corrosion, on the other hand, gradually thins the plates, eventually leading to leakage.

For this type of operating condition, heat-pipe-type or… is commonly used. Finned-tube type Heat exchangers. The former features complete isolation between the hot and cold sides, while the latter boasts a robust structure and excellent resistance to erosion.

Ametech can tailor an appropriate material solution—such as ND steel or 316L—based on flue gas temperature, dust concentration, and corrosion severity, and incorporates ash‑removal access channels into the design.

Key Considerations for Selection : Dust content, corrosion risk, and whether the flue gas temperature is below the acid dew point

Liquid waste heat recovery: Plate heat exchangers are the mainstay.

Liquid–liquid heat exchange is the most common scenario in industrial settings, with relatively clean fluids and moderate temperatures. Plate heat exchanger Highly suitable. Its advantages include a high heat transfer coefficient, a small footprint, and ease of disassembly and cleaning.

When the medium cleanliness is moderate and regular maintenance is required, select Detachable ; When the temperature and pressure are high or the medium is prone to leakage, select All-welded (No gasket, ensuring more reliable sealing.)

American Technologies can recommend either a detachable or fully welded design based on the corrosivity and cleanliness requirements of the process fluid, with materials ranging from 304 and 316L to titanium.

Key Considerations for Selection : Whether scaling is likely, cleaning frequency, and whether corrosivity is present.

Waste Steam Heat Recovery: Shell-and-Tube and All-Welded Plate Heat Exchangers Each Have Their Own Applications

The main challenge in exhaust steam recovery lies in the drastic reduction in volume upon steam condensation, which can easily lead to air lock or water hammer. Shell-and-tube heat exchanger It is a traditional choice, with a mature structure that is robust and durable. All-welded plate heat exchanger It offers higher efficiency, but requires selecting the appropriate plate configuration and implementing effective non-condensable gas venting and condensate drainage designs.

Ametech offers two solutions, with the specific selection depending on the user’s comprehensive assessment of efficiency, cost, and maintenance intervals.

Key Considerations for Selection : Whether non-condensable gases are vented and condensate is discharged smoothly.

Economic Evaluation and AMETECH’s Support

Once the technical solution has been finalized, another practical question still needs to be addressed: Is it worth it?

A commonly used indicator for measuring economic efficiency is Payback period — Equipment investment divided by annual energy‑saving savings. In industry practice, a payback period of 1 to 3 years is generally considered feasible; beyond 3 years, a reassessment is required. Additionally, factors such as the continuity of the heat source, cleaning and maintenance costs, and available on‑site installation space must also be taken into account.

Ametech can provide the following support in the field of waste heat recovery:

Early diagnosis : Assess the recovery value and equipment selection based on waste heat parameters (temperature, flow rate, composition, dust content, and corrosivity).

Product Selection : Available in various types, including plate‑type, all‑welded, shell‑and‑tube, heat‑pipe, and finned‑tube configurations, with materials ranging from 304 and 316L to titanium and Hastelloy.

Economic Reference : Assist in calculating the investment payback period and balancing technical feasibility with economic viability.

Project Implementation : End-to-end services, from manufacturing and inspection to installation guidance

If you are planning a waste heat recovery project or believe your existing system could benefit from optimization, please contact the AMETECH technical team for an initial consultation.

Keywords:Heat exchanger, system, vessel