Flue Gas Condensation for Energy Recovery

Modern incineration plants are equipped with a boiler system, transforming a major part of the energy content in the flue gases into steam. The steam generates electric power in turbine generators and produces heat in turbine condensers. The heat is fed into a district heating system.

Cost-Effective Method of Recovering Energy

A proven and cost-effective method of recovering energy for a district or local heating grid is achieved by condensing the water in flue gases. The amount of energy recovered depends on the district heating water temperature, and can be improved by using a heat pump, which can increase recovery by approximately 5 percent.

Flue gas condensation

By cooling the flue gas to below its dew point, it is possible to recover large quantities of latent heat. If the flue gas temperature after the boiler is approximately 150ºC it is possible by means of flue gas condensation, to increase the energy efficiency by an additional 20%. Condensation may take place either as a direct heat exchange between gas and district heating water, utilizing an intermediate cooling water circuit, or typically by using an absorption heat pump. For optimum energy efficiency, a combination of these methods are used.

Sweden and Denmark are considered world leaders in this type of energy efficiency improvement, with international interest in the process growing. This is partly a result of the EU's standards for energy-efficient waste incineration. A condensation system may enable an installation to meet the level requirements of the R1 factor. Flue gas condensation systems also reduce emissions, increase fuel flexibility and have the potential to reduce chemical usage and thus the amount of residual products. 

Condensate water is treated in our water treatment processes to reach purity levels of drinking water quality. Our condensing scrubbers are fitted with tower packing and droplet separators in ADIOX® dioxin separation material to eliminate dioxin problems. 

Our flue gas condensation solutions include:

• Condensing scrubbers 
• Metallic condensers 
• Water treatment 
• Heat pumps 
• Chillers 

Absorption technology

We supply absorption heat pumps for enhanced energy recovery (as described above) and absorption chillers to produce profitable comfort cooling in the summer. The chillers are placed locally in properties or centrally in a district cooling system and use excess heat from the district heating network as energy source. The installation requires very little maintenance. Besides the financial gains, the technology is eco-friendly and helps reducing CO2 emissions.

Proven Results & Experience

Babcock & Wilcox has extensive experience of servicing and maintenance of flue gas cleaning plants as well as compressor and absorption heat pumps. Our servicing activities include a complete program from delivery of spare parts to full servicing of entire plants.

• More than 35 installations firing waste or biofuels feature our flue gas condensation systems
• First installations in the 1980s are still in operation today

Conversions, upgrades and optimizations are carried out in order to ensure optimum efficiency for the customers’ equipment and to meet the demands of stricter environmental legislation. We offer service agreements for preventive maintenance including guaranteed call-out service to avoid unexpected stoppages. Our service organization also takes on installation, commissioning and servicing of absorption chillers.