Polymer Air PreHeater - APH

Recover additional heat

Prevent corrosion and fouling problems

Reduce your costs and CO2 emissions

Corrosion and fouling problems limit recovering additional heat from flue gas or exhaust air

Corrosion problems

Flue gases from burning fuels like refinery gas, fuel oil, off gases, blast furnace gas, oil, coal, biogas and biomass contain acidic elements. When you recover all the heat you will cool the flue gas or exhaust air through the acid dew point.  Acids will then condensate which leads to corrosion in conventional metal air preheaters and in the rest of the installation. 

Fouling problems

When exhaust air is cooled too deep, fouling may start to accumulate quicker and can eventually lead to blockage of your heat exchanger.

Waste heat can be recovered with air preheaters made with polymer

Heat up combustion air

The polymer APH is used for combustion air preheating on thermal processes. Ambient air is heated up and is fed to the burners. By burning hot combustion air instead of cold combustion air, less fuel is needed to achieve a certain duty. Due to acid condensation, heat recovery from flue gases can be demanding.

Heat up drying air

The heat from exhaust air is recovered and used to preheat fresh ambient air entering the dryer. This saves fuel on the fresh air heater. Due to the high humidity and presence of dust, heat recovery from drying processes can create corrosion and fouling problems.

Benefits of Polymer Air PreHeaters - APH

  • Corrosion resistance
    Corrosion resistance

    The APH contains polymer tube bundles, through which the flue gas or exhaust air flows. The polymer is resistant to the acids that are formed. The polymer can handle H2SO4, HCl, HF, H3PO4 and others.

  • Anti-fouling property
    Anti-fouling property

    The straight flow path of the flue gas through the APH and the low propensity of polymer to bind in combination with the possibility of in-line cleaning make the polymer APH suitable for fouling services.

  • Prevention of corrosion in duct and stack
    Prevention of corrosion in duct and stack

    Up to 80% of the acids will be condensed and removed from the flue gas by the polymer APH. This lowers the acid dew point substantially and prevents down stream corrosion.


Corrosive flue gas is no longer a show-stopper for heat recovery

Significant amounts of waste heat in flue gases or exhaust air from dryers, remain untapped due to acid dew point corrosion. Download the whitepaper to find out how to overcome this limitation.

Learn more about Polymer Air PreHeaters - APH

Patented Polymer Honeycomb Technology (PHT)

Standard modules

The polymer APH consists of polymer tubes that are combined into standardized bundles. The bundles are installed in a compact metal casing.


The individual polymer tubes are interconnected using the Polymer HoneyComb Technology (PHT). This stabilizes the tubes for flow induced vibrations.

Compact and light weight

The 1.5 meter long bundles provide an intense heat exchange process. The PHT technology creates a countercurrent flow path for hot and cold gas streams. Therefor the APH is compact and light weight.

Designed for perfection

Even distribution of temperature

The polymer APH is designed using Computational Fluid Dynamics to ensure homogeneous air and flue gas distribution which ensures maximum performance of the air preheater under all conditions. Due to the even distribution of the flow,  the temperature of the flue gas coming out of the APH is everywhere the same.

No dead zones

The vertical downward flow of flue gas or exhaust air ensures proper drainage of condensate.  Both gas and condensate flow in the same direction assisted by gravity. There are no baffles or turns where fouling can accumulate.

Disengagement of acids and flue gas

Liquids are separated from the cooled flue gas flow in the bottom segment of the polymer APH. Liquids are removed via a drain.

Easy cleaning and maintenance

Cleaning with water

The polymer APH can be easily cleaned manually when you open the top lid during a stop. There is also the possibility to install an inline cleaning system.  Each bundle has its own spray nozzle, which can clean the bundle during operation.


Maintenance of the polymer APH is easy.


Cleaning and Maintenance
Polymer Air PreHeater

In this video we show you how to remove bundles from the polymer Air Preheater (APH), and how to inspect and clean them.

Learn more about the maintenance and cleaning of the Polymer Air Preheater


Download Operating & Maintenance manual

How to Remove, Inspect, Clean and Install a Bundle of Polymer Air Preheaters


Condensate treatment

Learn more about the formation, protection, removal and treatment of condensates.

Technical details

Operating range

F: 5.000 - 500.000+ kg/hr
Tdesign: 200 °C
Pdesign: 150 mbar
ΔP: ~6 mbar

For operating temperatures above 200 ºC a combination of a metal APH in series with a polymer APH is applied.

Thermal expansion

The polymer APH is designed in such a way that the polymer bundles can thermally expand without stresses acting on the polymer tubes. The air preheater can be heated-up and cooled down instantaneously. There is no time dependent heating profile required.


The design of the polymer APH is based on the requirements of a client and process data of a specific situation. The dimensions are derived from the hot and cold flows, temperatures, composition of the flows. The nozzle orientation is flexible and matched to the ducting design.


The polymer bundles of the air preheater can cope with acids like sulphuric acid, hydrofluoric acid, hydrochloric acid and phosphoric acid.

The casing has four segments (see schematic overview above). The construction material can be selected for each segment of the air preheater individually based on the application.

Receive all technical details required for the installation concept


Polymer Airpreheater Installation concepts

Learn more about the formation, protection, removal and treatment of condensates.

Your path to lower CO2 emissions, energy consumption and costs


Technical assessment

Our process engineers assess the technical feasibility of additional heat recovery on your process. The potential reduction in CO2 emissions, energy consumption and costs is determined.


Heat exchanger design and Business Case

A proposal is made with all technical details and economic assessment with payback time. You have everything you need for budget approval.


Realize project delivery

HeatMatrix designs, delivers and -upon request- installs a complete heat recovery system in your factory. For bigger projects we work with your preferred Engineering company from start to implementation.


The design temperature of the polymer APH is 200 ºC. When you have a higher flue gas temperature, a combination of a metal and polymer APH can be installed.

Most important is the assessment of the thermal balance, hydraulics and lay-out. A checklist with more details can be provided upon request. Please send us an email.

No, the APH is only for gas-gas heat exchange. The polymer ECO can be used to heat-up a water stream.