Benefits

• Compact and efficient design based on helix smoke tubes

• Easy improvement of Carbon Intensity Indicator (CII)

• Short payback time (typically 1–2 years) through up to

25% fuel savings on the fired boiler

• Reduced wear and maintenance on the fired boiler

• Long service life thanks to self-cleaning Turbo Clean

technology

Working principle

The Aalborg XS-TC7A is installed after a vessel’s auxiliary

engine. When the exhaust gas passes over its heat¬ing

surface, the waste heat energy in the gas is absorbed for the

production of steam. The economizer can be adapted for dry

running in the event of an emergency.

The Aalborg XS-TC7A features an optimized convection part

that augments heat transfer by increasing turbulence at the

exhaust gas boundary layer. This contributes to increased

steam production while reducing the economizer’s weight

and footprint.

The economizer is designed for forced circulation and is used

in connection with one or more fired boilers, which act as the

steam space.

The Alfa Laval Aalborg XS-TC7A is an efficient

smoke-tube economizer. Easy to install, operate

and maintain, it reduces the use of the fired boiler

by recovering heat energy that otherwise would

be lost through the exhaust gas. This ensures

a rapid return on investment.

Thanks to the helix shape of its smoke tubes,

the Aalborg XS-TC7A offers a large heat transfer

area within a compact footprint. This enhances

its performance and makes it the smallest smoke

tube economizer on the market.

Application

Only a portion of the fuel energy released by marine engines

actually goes to propulsion. A large amount of it escapes as

heat, and it makes sense to reclaim as much of this energy

as possible. This is true not only for main engines, but for

auxiliary engines as well.

Steam produced with the Aalborg XS-TC7A can support or

fulfil steam needs in port, but it can also serve other functions.

For vessels whose long-stroke main engines produce

cooler exhaust, it can provide a needed steam boost during

a voyage. If there is no steam shortage while sailing, the

additional steam produced with the economizer can be used

to generate electricity, for example by means of Organic

Rankine Cycle (ORC) technology.

Reduce fuel costs and emissions

The Aalborg XS-7V is part of Alfa Laval’s broad waste heat

recovery portfolio, which builds on over 40 years of waste

heat recovery experience. We take a holistic approach,

helping you identify the optimal economizer setup for your

particular vessel.

Our solution is always tailored to your steam requirements,

the amount of exhaust gas and your vessel’s unique characteristics.

It can include:

• Smoke-tube or water-tube economizers

• Single-inlet or dual-inlet solutions

• Compact economizers to minimize installation footprint

The Alfa Laval Aalborg XS-7V is a robust smoke-tube economizer.

Easy to install, operate and maintain, it reduces the use of the

fired marine boiler by recovering heat energy that otherwise

would be lost through the exhaust gas. The Aalborg XS-7V is

similar to the Aalborg XS-2V, but it shares a steam space with

the fired boiler instead of having its own steam space.

Its proven design includes a dual-inlet option, which creates

high installation flexibility.

Easy steam production with dual-inlet flexibility

• Simple and reliable design based on smoke tubes

• Easy improvement of Carbon Intensity Indicator (CII)

• Short payback time (typically 1–2 years) through up to 25%

fuel savings on the fired boiler

• Reduced wear and maintenance on the fired boiler

• Dual-inlet option allowing connection of two engines to one

economizer

Application

Only a portion of the fuel energy released by marine engines

actually goes to propulsion. A large amount of it escapes as

heat, and it makes sense to reclaim as much of this energy

as possible. This is true not only for main engines, but for

auxiliary engines as well.

Steam produced with the Aalborg XS-2V or XS-7V can

support or fulfil steam needs in port, but it can also serve

other functions. For vessels whose long-stroke main engines

produce cooler exhaust, it can provide a needed steam

boost during a voyage. If there is no steam shortage while

sailing, the additional steam produced with the economizer

can be used to generate electricity, for example by means

of Organic Rankine Cycle (ORC) technology.

Benefits

• Simple and reliable design based on smoke tubes

• Easy improvement of Carbon Intensity Indicator (CII)

• Short payback time (typically 1–2 years) through up

to 25% fuel savings on the fired boiler

• Reduced wear and maintenance on the fired boiler

• Dual-inlet option allowing connection of two engines

to one economizer

Working principle

The Aalborg XS-2V and XS-7V are installed after a vessel’s

main or auxiliary engines. When the exhaust gas passes over

the economizer’s heating surface, the waste heat energy in

the gas is absorbed for the production of steam. Dry running

is possible in the event of an emergency.

The two models differ in how produced steam is handled:

• The Aalborg XS-2V is a full exhaust gas boiler with its own

steam space, which can operate independently from the

fired boiler.

• The Aalborg XS-7V is designed for forced circulation

and is used in connection with one or more fired boilers,

which act as the steam space.

Waste heat recovery economizers for marine engines

The Alfa Laval Aalborg XS-2V and XS-7V are robust smoke-tube

economizers. Easy to install, operate and maintain, they reduce

the use of the fired boiler by recovering heat energy that

otherwise would be lost through the engine exhaust gas.

This ensures a rapid return on investment. The Aalborg XS-2V

is equipped with its own steam space, which makes it a

complete exhaust gas boiler. The Aalborg XS-7V shares a steam

space with the fired boiler. The proven design of both

economizers includes a dual-inlet option, which creates high

installation flexibility.

Design

Built for simplicity and reliability, the Aalborg XS-2V and

XS-7V have a vertical, all-welded design with straight smoke

tubes. The option of dual inlets allows one economizer to

serve two engines, with half the tubes dedicated to one

engine and half dedicated to the other. This can reduce

installation costs and complexity.

The smoke-tube design is easy to clean and maintain,

especially as the high gas velocity through the economizer

minimizes fouling. If needed, individual smoke tubes can also

be repaired or replaced.

Working principle

The Aalborg Micro is installed after a vessel’s auxiliary engine

(or small main engine). It has a short start-up time of just

two minutes. When the exhaust gas passes over its heating

surface, the waste heat energy in the gas is absorbed for the

production of hot water or steam. An internal damper, which

allows up to 80% of the exhaust gas to bypass the heating

surface, keeps back pressure within safe limits.

The Aalborg Micro is not designed with its own steam space.

It is used in connection with one or more fired boilers, which

act as the steam/water space. Forced-circulation pumps pro

vide the Aalborg Micro with water at saturation temperature

from the fired boiler(s).

In the Aalborg Micro, heat from the engine exhaust gas is

transferred to the water side by convection. The generated

steam/water mixture is then discharged into the steam space

of the fired boiler(s), where the heavier water particles sepa

rate from the steam.

Benefits

• Extremely compact, plug-and-play design for easy retrofit

• Easy improvement of Carbon Intensity Indicator (CII)

• Short payback time (typically 1–2 years) through up to

25% fuel savings on the oil-fired boiler

• Reduced wear and maintenance on the fired boiler

• Internal damper for dynamic management of

pressure drop

Design

Built for lasting performance, the Aalborg Micro has a durable

construction where the coaxial tubes of the heating surface

are arranged within a vertical cylindrical shell plate. The

heating surface is designed for easy maintenance, with an

integrated soot blower that supports the daily cleaning of

the coiled fin tubes.

In operation, a control damper forces the exhaust gas flow

from the engine to pass between the tube coils. This damper

also acts as an internal bypass, allowing back pressure to be

regulated without the need for an external bypass.

The Alfa Laval Aalborg Micro is a uniquely compact

water-tube economizer. Easy to install, operate and

maintain, it reduces the use of the fired boiler by

recovering heat energy that otherwise would be

lost through the engine exhaust gas. This ensures

a rapid return on investment.

Despite its minimal footprint, height and weight,

the Aalborg Micro has an extended heating surface

created by coiled fin tubes. Even more efficient than

smoke-tube economizers, it provides an ideal retro

fit solution where no other economizer will fit.

Application

Only a portion of the fuel energy released by marine engines

actually goes to propulsion. A large amount of it escapes

as heat, and it makes sense to reclaim as much of this en

ergy as possible. This is true for auxiliary engines as well as

main engines.

Steam produced with the Aalborg Micro can support or fulfil

steam needs in port, but it can also serve other functions.

For vessels whose long-stroke main engines produce

cooler exhaust, it can provide a needed steam boost during

a voyage. If there is no steam shortage while sailing, the

additional steam produced with the Aalborg Micro can

be used to generate electricity, for example by means of

Organic Rankine Cycle (ORC) technology.