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The Aalborg XW-TG is a water tube, forced circulation exhaust

gas economizer designed to utilize thermal energy in diesel

engine exhaust gas. The standard Aalborg XW design has

been enhanced to more efficiently utilize the wasted energy

after large diesel engines with saved fuel consumption and

reduced CO2 emissions as a result.

Aalborg XW-TG generates superheated steam for power

generation by means of a steam turbine driven generator

(turbo generator).

The Aalborg XW-TG is based on and has the same charac

teristics as our well-known Aalborg XW which is a water tube,

forced circulation exhaust gas economizer with double gilled

tubes specially designed for heat recovery from diesel engine

exhaust gas.

When applied for large heat recovery rates, the heating surfaces

are required to be much increased in size and it is increasing

ly more important to focus on operation reliability to provide

full benefit of the relatively high investment.

The Aalborg XW is a water tube, forced circulation exhaust gas

economizer. It is specially designed to utilize thermal energy in

diesel engine exhaust gas but the basic design suits numerous

applications.

Boiler characteristics:

•  Forced-circulation exhaust gas economizer

•  Water tube economizer with gilled tubes for exhaust gas

heat recovery

•  Robust, well-proven construction, able to withstand

vibrations and exhaust gas pulsation

•  Heating surface composition which ensures the required

output from the most compact unit

•  Efficient, well-proven cleaning system with steam or air

soot blowers

•  Superheater and preheater as an option

The Aalborg XW is a water tube, forced circulation exhaust gas

economizer. It is specially designed to utilize thermal energy in

diesel engine exhaust gas but the basic design suits numerous

applications.

Steam capacity: 0.2 – 17.0 t/h

Design pressure: 18 bar(g) or 24 bar(g)

Description

The Aalborg XW is a water tube, forced circulation exhaust

gas economizer. It is specially designed for heat recovery

from diesel engine exhaust gas but the basic design suits

numerous applications.

The heating surface is made of double gilled tubes with a

spacing which minimizes soot build-up. It is supplied with an

efficient cleaning system with steam or with compressed

air sootblowers.

The economizer can be supplied with a dividing wall system

for connection of several exhaust gas sources to one econo

mizer.

The Aalborg XW may be used in conjunction with an oil-fired

auxiliary boiler or a separate steam drum, in both cases act

ing as a steam/water separator.

The Alfa Laval Aalborg XS-2V 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-2V is similar to the Aalborg

XS-7V, but it is equipped with its own steam space, which makes it a

complete exhaust gas boiler. Its proven design includes a dual-inlet

option, which creates high installation flexibility.

Characteristics

• Vertical smoke tube exhaust gas economizer

• Own steam space or forced circulation

• Designed to utilize thermal energy in exhaust gases

• Quick start up

• Simple and automatic opeation

• Easy maintenance

• Standardized components

• All-welded contructions

• Integrated silencer as an option

• Compact and easy to install

Design data

• Steam capacity: 0.5 – 5 t/h

• Heat capacity: 0.3 – 4 MW

• Design pressure:10 bar(g)

Dual-inlet flexibility and steam independence

• Simple and reliable design based on smoke tubes – with its own

steam space

• 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

Characteristics

• Vertical smoke tube exhaust gas economizer

• Own steam space or forced circulation

• Designed to utilize thermal energy in exhaust gases

• Quick start up

• Simple and automatic opeation

• Easy maintenance

• Standardized components

• All-welded contructions

• Integrated silencer as an option

• Compact and easy to install

Reduce fuel costs and emissions

The Aalborg XS-2V 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 economizer is carried out with the smoke tubes welded to the tube

plates at both ends, and this robust design can, in emergency cases,

withstand running dry.

The Aalborg XS-2V comes with its own steam space and is able to operate

independently from the oil-fired boiler/steam drum.

The sizes of the economizers depend on required steam capacity, amount

of exhaust gas, temperature, and working pressure.

Design

Built for simplicity and reliability, the Aalborg XS-TC7A has a

vertical, all-welded design with helix smoke tubes. The helix

design of the tubes greatly increases the available heat trans

fer area, which makes this the smallest smoke-tube econo

mizer on the market. Together with the optimized convection

section, it ensures a high ratio of output to weight.

The helix tubes and the economizer’s self-cleaning Turbo

Clean technology both reduce soot build-up, which makes

XS-TC7A easy to clean and maintain. If needed, individual

smoke tubes can also be repaired or replaced.

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