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Exhaust gas heat exchangers

Exhaust gas heat exchangers are critical components in energy recovery systems, capturing waste heat from the exhaust streams of engines, boilers, and industrial combustion processes to produce hot water, steam, or thermal energy for further use. They are widely applied in combined heat and power (CHP) installations, marine propulsion systems, biogas plants, and various industrial processes. Over time, the tubes and heat transfer surfaces inside these systems accumulate fouling from soot, carbon deposits, and other combustion by-products. This buildup reduces heat transfer efficiency, increases fuel consumption, and puts unnecessary strain on the overall system. Regular and preventive tube cleaning is essential to keep exhaust gas heat exchangers operating at peak performance.

Fouling issues in exhaust gas heat exchanger tubes

Exhaust gas heat exchangers operate in demanding conditions, continuously exposed to high-temperature combustion gases containing unburned fuel particles, carbon compounds, and other contaminants. As these gases pass through the heat exchanger tubes, deposits gradually accumulate on the internal surfaces where heat transfer occurs, making the tubes particularly susceptible to fouling over time. The type and rate of fouling depends heavily on the fuel used: gaseous fuels such as natural gas produce relatively low fouling, while liquid fuels such as diesel or heavy fuel oil result in significantly faster and more aggressive deposit formation.

Commonly found deposit types in exhaust gas heat exchanger tubes are:

  • Soot (carbon dust from combustion)
  • Unburned fuel residues
  • Particulate matter and ash
  • Rust (corrosion)
  • Siloxane deposits (in biogas applications)
  • Hardened carbon and coke-like deposits

Effects of fouling in exhaust gas heat exchanger tubes

When heat transfer tubes inside an exhaust gas heat exchanger become fouled, the system’s efficiency is significantly reduced. Below, you can find some of the key effects of fouling in these components.

  • Reduced heat-transfer rate: Fouling creates an insulating layer on the tube surfaces, restricting the transfer of heat between the hot exhaust gases and the water or thermal fluid circuit. Deposits such as soot, carbon, and particulate matter increase thermal resistance, directly reducing the amount of recoverable heat energy.
  • Increased energy consumption and fuel costs: As heat recovery efficiency declines, more fuel must be consumed to meet the same energy output. In CHP systems, where fuel efficiency is central to the business case, even modest fouling can significantly erode the economic return of the installation.
  • Shorter equipment lifespan: Persistent fouling accelerates wear on tube surfaces and internal components, leading to more frequent maintenance interventions, higher repair costs, and a shorter overall equipment lifespan.
  • Corrosion and damage: Certain deposit types, particularly soot combined with moisture or sulphur compounds in biogas applications, can promote localised corrosion on tube surfaces. Over time, this weakens the tubes and increases the risk of leaks or structural damage, leading to costly downtime.

Improve exhaust gas heat exchanger efficiency

Cleaning exhaust gas heat exchanger tubes is a crucial activity to maintain a highly efficient system and maximise the return on your energy recovery installation. The key to effective cleaning and the best cleaning results lies in acting before deposits become too severe. Light to medium-hard deposits such as soot, carbon dust, and particulate matter can be effectively and reliably removed using mechanical cleaning with rotating brushes. Once deposits harden and carbonise significantly, cleaning becomes considerably more challenging and results are harder to guarantee, even with specialised tools. This makes preventive and regular cleaning the most reliable strategy for keeping your system in optimal condition.

Goodway Benelux offers the following cleaning solution for exhaust gas heat exchanger tubes:

  • Mechanical cleaning with rotating brushes: The most effective and reliable solution for removing light to medium-hard deposits inside exhaust gas heat exchanger tubes, such as soot, carbon dust, particulate matter, and light rust. Goodway® rotating brush systems are designed to thoroughly clean tube inner surfaces, restoring heat transfer efficiency quickly and with minimal downtime. For more severe or heavily hardened deposits, specialised cleaning tools are available, however in these cases a full cleaning result is harder to guarantee. Therefore, it is strongly recommended to setup a regular cleaning schedule to prevent deposits from reaching this stage.

Interested in what Goodway Benelux offers for:

Exhaust gas heat exchangers

From pre-sales inquiries to technical support, Goodway Benelux is available to assist customers at every stage. The company also provides on-site support, training, and product demonstrations. Their dedicated sales representatives and project engineers are ready to answer questions and provide guidance throughout the entire process.

Jard is here to help.

Sales engineer

info@goodwaybenelux.com+31 (0)183 216 170