Exhaust gas economizer
Exhaust gas economizers capture waste heat energy from engines, gas turbines and more, enabling its reuse for steam production or other processes. This saves fuel, which provides rapid payback and helps reduce CO2 and other emissions. It also reduces the running hours of the fired boiler/heater, which lowers maintenance costs. Our Alfa Laval Aalborg portfolio includes a wide range of economizers for industrial and marine use, as well as standalone exhaust gas boilers with integrated steam drums.
Benefits of Alfa Laval Aalborg exhaust gas economizers
- Significantly reduced emissions of CO2 and other greenhouse gases
- Short payback time through fuel savings due to reduced reliance on combustion
- Compact design ensured by optimized heating surfaces with high thermal efficiency
- Innovative options for easy installation and integration – even in retrofit situations
- Specific engineering to match each engine’s data and operating conditions
We have effective waste heat recovery solutions to match a wide variety of needs. Our Alfa Laval Aalborg exhaust gas economizers and exhaust gas boilers combine exceptional thermal efficiency with proven reliability.
What makes Alfa Laval Aalborg exhaust gas economizers different?
Alfa Laval Aalborg exhaust gas economizers and exhaust gas boilers build on decades of waste heat recovery experience – and more than a century of work with steam and heat generation as a whole.
Compact, lightweight designs
Aalborg exhaust gas economizers and exhaust gas boilers are extremely efficient, both thermally and in terms of space and weight. Certain models are optimized for space-constrained applications, enabling waste heat recovery retrofits that would not otherwise be possible.
Extended heating surfaces
Design elements such as gilled tubes, finned tubes and helix tubes maximize the heating surfaces in Aalborg exhaust gas economizers and exhaust gas boilers. This optimizes waste heat recovery efficiency while keeping footprint to a minimum.
Effective self-cleaning
Many Aalborg exhaust gas economizers and exhaust gas boilers have built-in soot blowers or other self-cleaning features. These ensure safety and help to maintain high thermal efficiency while minimizing the downtime needed for cleaning heating surfaces.
Adaptability for varying loads
Waste heat recovery applications are often subject to load changes. Integrated bypass systems and other features allow Aalborg exhaust gas economizers and exhaust gas boilers to operate safely and efficiently under partial or fluctuating loads.
Natural or forced circulation
Depending on the model and application, Aalborg exhaust gas boilers can be delivered with natural or forced circulation. Natural circulation offers simplicity and high reliability, while forced circulation can provide greater flexibility where needed.
Industrial waste heat recovery
Alfa Laval Aalborg exhaust gas economizers and exhaust gas boilers are available for various waste heat recovery needs in industry. In most cases, they can be delivered as fully assembled modules or tailored on site, creating a flexible scope of supply.
Marine waste heat recovery
Alfa Laval pioneered waste heat recovery at sea, and today’s portfolio offers a unique breadth of possibilities. Regardless of the vessel type or the fuel in use, Alfa Laval Aalborg exhaust gas economizers and exhaust gas boilers can lower OPEX and improve CII ratings.
How it works
Exhaust gas economizers recapture the heat in flue gases from engines and gas turbines, as well as from furnaces and kilns used in industrial processes. Instead of being lost through the stack or funnel, the heat can be applied to steam generation, hot water production or heating of thermal oil – without consuming additional fuel or energy. In many cases, the recovered heat can also be used for power generation.
Hot flue gas enters the economizer, which contains tubes that transfer the heat to water or thermal oil. Depending on the application and customer choice, the tubes may be either smoke tubes or water tubes. In a smoke-tube design, flue gas flows through the tubes and heats the surrounding medium. In a water-tube design, water flows through the tubes while the flue gas passes over them. The tubes themselves may be straight, helix-formed or even coiled. Likewise, features such as fins or gills may be used to extend the heat transfer surface.
In most cases, economizers feed produced steam into an external steam drum, which may be that of a fired boiler. However, certain economizers have an integrated steam drum of their own, making them standalone exhaust gas boilers.
Case stories
Creating a path to efficiency for DFDS
The Alfa Laval Aalborg Micro economizer created energy-saving possibilities that were previously unthinkable on three DFDS ferries. With its uniquely compact design, it allowed waste heat recovery to be installed where there was no space for a conventional economizer solution.
Maximized recovery at multi-pressure levels
On Royal Caribbean Group’s Icon of the Seas, Alfa Laval Aalborg XWi exhaust gas boilers with natural circulation have increased waste heat recovery by 33%. Dual pressure stages allow heat demands to be met while also producing super heated steam for power production.
Alfa Laval Marine Service
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