MAC™ is a trademark of Magaldi Power S.p.A.

Allen-Sherman-Hoff is a division of Diamond Power International, Inc.

MAC™ Systems are supplied in the United States by Allen-Sherman-Hoff under a license

from Magaldi Power S.p.A.

This information contain herein is solely for informational purposes and is not offered,

nor should be construed, as a warranty or contractual obligation. Diamond Power

International, Inc. Reserves the right to make design or material changes without notice.

©2005 Diamond Power International, Inc. All rights reserved. ASH-9342-0805-00

Magaldi Ash CoolerDry Bottom Ash System

www.a-s-h.com 1.888.ASH.PARTS

™

Field Evaluation ServicesAllen-Sherman-Hoff ’s team of engineers are available to perform an evaluation of your

existing bottom ash system to determine the benefits that may be realized by conversion

to a MAC™ System. For more information about the MAC™ System, please contact an

Allen-Sherman-Hoff representative at 1-888-ASH-PARTS.

The success of the MAC™ system can be

attributed to the following benefits over

traditional wet bottom ash systems:

•Eliminates water usage in cooling and conveying

bottom ash

•Reduces carbon content in bottom ash

•Captures heat energy from ash and returns to boiler

•Provides for potential sale of dry, low carbon ash

•Reduces operational and maintenance costs

compared to conventional wet systems

•Fully automatic system from boiler throat to

storage silo

The MAC™ System has been installed in

both new boiler and retrofit projects on many

different boiler types and makes in a wide

range of operating conditions.

WORKING CONCEPT

The main component of the MAC™ System is the MAC™ extractor, which is designed to operate in harsh conditions

including exposure to high temperatures and shock loads caused by the fall of large clinkers. The MAC™ extractor is

connected to the boiler throat through a refractory-lined hopper or a transition chute, which provides a volume for

temporary ash storage. The hopper is available with bottom doors which can be closed to isolate the MAC™ extractor

and for ash storage. The hopper or transition chute is connected to the boiler throat by a high-temperature mechanical

seal that allows for boiler expansion.

The Magaldi Superbelt Construction Operation

A key element of the MAC™ extractor is the Magaldi Superbelt which receives and extracts bottom ash falling from the boiler. The Superbelt is enclosed inside the sealed casing of the MAC™ extractor. During the conveying of ash on the Superbelt, ash is cooled by a small, controlled amount of ambient air that flows by natural draft into the MAC™ System casing through inlet valves. In addition, the air provides oxygen to the unburned ash, allowing a more complete combustion and return of heat to the boiler. Data from existing installations indicate reverse air flow does not disturb the combustion process and does not influence NOx formation.

From the MAC™ extractor, the cooled ash is discharged onto a crusher, which reduces the large ash clinkers to a size suitable for conveying to a silo.

Any ash fines that fall on the casing floor are swept off by the spill chain, a small scraper conveyor installed under the Superbelt.

Boiler

Mechanical Seal

Bottom Doors (Optional)

Superbelt

Spill Chain

Crusher

Pan

Mesh Belt

Carrying Idler

Downstream EquipmentMAC Extractor

Hopper or Transition Chute

The patented MAC™ (Magaldi

Ash Cooler) Dry Bottom

Ash System, is a unique system

for dry extraction, cooling and

handling of bottom ash from

pulverized coal-fired boilers.

With over 70 systems installed

worldwide, the MAC™ Dry Bottom

Ash System is the world’s leading

dry bottom ash-handling system

for utility boilers.

The Superbelt is constructed with a stainless steel mesh belt that carries partially overlapping stainless steel pans -making the belt conveyor almost completely sealed.

The patented method of connecting the pans to the mesh belt leaves all components free to expand in any direction, without permanent deformation. As a result, the Superbelt withstands the high temperatures encountered under the boiler throat.

The Superbelt is supported by carrying idlers that are mounted across the entire width of the belt to provide support for heavy mechanical impacts. All idler bearings are fitted outside the casing to protect them from heat and allow easy lubrication. The driving force is transmitted by friction between the head pulley and the belt, while a pneumatic take-up device on the tail pulley supplies a constant tension. Wear of the belt is minimized because there is normally no relative motion between the belt and the ash.

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The success of the MAC™ system can be

attributed to the following benefits over

traditional wet bottom ash systems:

•Eliminates water usage in cooling and conveying

bottom ash

•Reduces carbon content in bottom ash

•Captures heat energy from ash and returns to boiler

•Provides for potential sale of dry, low carbon ash

•Reduces operational and maintenance costs

compared to conventional wet systems

•Fully automatic system from boiler throat to

storage silo

The MAC™ System has been installed in

both new boiler and retrofit projects on many

different boiler types and makes in a wide

range of operating conditions.

WORKING CONCEPT

The main component of the MAC™ System is the MAC™ extractor, which is designed to operate in harsh conditions

including exposure to high temperatures and shock loads caused by the fall of large clinkers. The MAC™ extractor is

connected to the boiler throat through a refractory-lined hopper or a transition chute, which provides a volume for

temporary ash storage. The hopper is available with bottom doors which can be closed to isolate the MAC™ extractor

and for ash storage. The hopper or transition chute is connected to the boiler throat by a high-temperature mechanical

seal that allows for boiler expansion.

The Magaldi Superbelt Construction Operation

A key element of the MAC™ extractor is the Magaldi Superbelt which receives and extracts bottom ash falling from the boiler. The Superbelt is enclosed inside the sealed casing of the MAC™ extractor. During the conveying of ash on the Superbelt, ash is cooled by a small, controlled amount of ambient air that flows by natural draft into the MAC™ System casing through inlet valves. In addition, the air provides oxygen to the unburned ash, allowing a more complete combustion and return of heat to the boiler. Data from existing installations indicate reverse air flow does not disturb the combustion process and does not influence NOx formation.

From the MAC™ extractor, the cooled ash is discharged onto a crusher, which reduces the large ash clinkers to a size suitable for conveying to a silo.

Any ash fines that fall on the casing floor are swept off by the spill chain, a small scraper conveyor installed under the Superbelt.

Boiler

Mechanical Seal

Bottom Doors (Optional)

Superbelt

Spill Chain

Crusher

Pan

Mesh Belt

Carrying Idler

Downstream EquipmentMAC Extractor

Hopper or Transition Chute

The patented MAC™ (Magaldi

Ash Cooler) Dry Bottom

Ash System, is a unique system

for dry extraction, cooling and

handling of bottom ash from

pulverized coal-fired boilers.

With over 70 systems installed

worldwide, the MAC™ Dry Bottom

Ash System is the world’s leading

dry bottom ash-handling system

for utility boilers.

The Superbelt is constructed with a stainless steel mesh belt that carries partially overlapping stainless steel pans -making the belt conveyor almost completely sealed.

The patented method of connecting the pans to the mesh belt leaves all components free to expand in any direction, without permanent deformation. As a result, the Superbelt withstands the high temperatures encountered under the boiler throat.

The Superbelt is supported by carrying idlers that are mounted across the entire width of the belt to provide support for heavy mechanical impacts. All idler bearings are fitted outside the casing to protect them from heat and allow easy lubrication. The driving force is transmitted by friction between the head pulley and the belt, while a pneumatic take-up device on the tail pulley supplies a constant tension. Wear of the belt is minimized because there is normally no relative motion between the belt and the ash.

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The Magaldi Postcooler provides dry mechanical transport to a silo. The Postcooler is a steel belt conveyor inside a sealed casing, providing further cooling of ash during the conveying process.

Operations with space constraints will find the pneumatic system beneficial because the downstream conveying system can be routed through very restricted spaces. A second crushing stage further reduces the size of

the ash before transport.

If the dry bottom ash is pulverized by mills to a very fine size, it can be mixed with the fly ash. This can lead to a simplification of the overall ash handling system and potential for increased ash sales revenues. In this configuration, usually a Magaldi Postcooler is used to transport the ash

from the crusher to the pulverizers, followed by pneumatic conveying to

the fly ash silo.

Pneumatic Conveying to Silo

Pneumatic Conveying to Fly Ash SiloMechanical Conveying to Silo

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SYSTEM CONFIGURATIONSSince the ash is delivered dry, there are several options available for the configuration of the equipment downstream of the crusher. The most commonly applied configurations are described below.

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Hopper

Crusher

Pneumatic Pressure System

To Fly Ash Silo

MAC Extractor

Post CoolerPulverizersPost Cooler

SiloCrusher

MAC Extractor

Hopper

Hopper

Silo

MAC Extractor Bin

Primary Crusher

Secondary Crusher

Pneumatic Vacuum System

The Magaldi Postcooler provides dry mechanical transport to a silo. The Postcooler is a steel belt conveyor inside a sealed casing, providing further cooling of ash during the conveying process.

Operations with space constraints will find the pneumatic system beneficial because the downstream conveying system can be routed through very restricted spaces. A second crushing stage further reduces the size of

the ash before transport.

If the dry bottom ash is pulverized by mills to a very fine size, it can be mixed with the fly ash. This can lead to a simplification of the overall ash handling system and potential for increased ash sales revenues. In this configuration, usually a Magaldi Postcooler is used to transport the ash

from the crusher to the pulverizers, followed by pneumatic conveying to

the fly ash silo.

Pneumatic Conveying to Silo

Pneumatic Conveying to Fly Ash SiloMechanical Conveying to Silo

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SYSTEM CONFIGURATIONSSince the ash is delivered dry, there are several options available for the configuration of the equipment downstream of the crusher. The most commonly applied configurations are described below.

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Hopper

Crusher

Pneumatic Pressure System

To Fly Ash Silo

MAC Extractor

Post CoolerPulverizersPost Cooler

SiloCrusher

MAC Extractor

Hopper

Hopper

Silo

MAC Extractor Bin

Primary Crusher

Secondary Crusher

Pneumatic Vacuum System

Enhanced dependability and safety

The dependability of the MAC™ System can result in

increased boiler availability by:

•Reducing forced boiler outages - the MAC™ is designed so maintenance

and repair can be performed online

•Reducing risk of sudden failures - able to withstand the impact of large

clinkers falling from boilers

•Reducing safety risks - all moving parts are inside the casing and no

rodding of ash is required

Reduces water-related problems

By eliminating the use of water for ash cooling and conveying,

a series of operational and environmental problems are eliminated

when using the MAC™ System.

•Eliminates ash dewatering bins, ponds or waste water treatment

•Eliminates pumps, heat exchangers and pH-control

•Minimizes corrosion due to cooling and conveying water

•Eliminates risk of ice formation from wet ash

•Reduces safety problems due to hot water splashing or vapor explosions

•Reduces environmental impact due to waste-water discharge

Facilitates lower operation & maintenance costs

•Extended lifecycle - The Superbelt life is extended due to unique low

friction design.

•Resists plugging - The MAC™ extractor design ensures that any ash clinker

that can pass through the boiler throat is transferred to the crusher

•Low maintenance requirements - regular maintenance activities can be carried

out with the system in operation

•Fully automatic operation - eliminates need for costly manual operations such

as use of front end loader to transfer ash from bunker to truck

•Lower energy consumption - because no water has to be moved, only dry ash

Heat recovery from the ash to the boiler

In coal-fuel fired boilers, a significant amount of energy is contained in

the bottom ash. In a wet bottom ash system, this energy is completely lost

because the ash is quenched. In the MAC™ System, the cooling air captures

the heat from the ash and provides oxygen for post-combustion resulting in:

•A substantial burn-out of remaining carbon in bottom ash

•Significant recovery of heat contained in the bottom ash. This heat recovery

reduces the heat and fuel losses from the boiler which can contribute increased

boiler efficiency

It is routinely demonstrated that the amount of cooling air used in the MAC™

System (typically less than one percent of total boiler combustion air) does not

have an adverse effect on the boiler operation

Delivery of dry ash

The bottom ash is delivered dry, which offers the following benefits:

•Simplified configuration of the downstream processing equipment

•After pulverization, dry low carbon content bottom ash can be mixed with

fly ash, leading to potential for increased ash sales revenues and simplified

ash management

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OPERATING CHARACTERISTICS

Enhanced dependability and safety

The dependability of the MAC™ System can result in

increased boiler availability by:

•Reducing forced boiler outages - the MAC™ is designed so maintenance

and repair can be performed online

•Reducing risk of sudden failures - able to withstand the impact of large

clinkers falling from boilers

•Reducing safety risks - all moving parts are inside the casing and no

rodding of ash is required

Reduces water-related problems

By eliminating the use of water for ash cooling and conveying,

a series of operational and environmental problems are eliminated

when using the MAC™ System.

•Eliminates ash dewatering bins, ponds or waste water treatment

•Eliminates pumps, heat exchangers and pH-control

•Minimizes corrosion due to cooling and conveying water

•Eliminates risk of ice formation from wet ash

•Reduces safety problems due to hot water splashing or vapor explosions

•Reduces environmental impact due to waste-water discharge

Facilitates lower operation & maintenance costs

•Extended lifecycle - The Superbelt life is extended due to unique low

friction design.

•Resists plugging - The MAC™ extractor design ensures that any ash clinker

that can pass through the boiler throat is transferred to the crusher

•Low maintenance requirements - regular maintenance activities can be carried

out with the system in operation

•Fully automatic operation - eliminates need for costly manual operations such

as use of front end loader to transfer ash from bunker to truck

•Lower energy consumption - because no water has to be moved, only dry ash

Heat recovery from the ash to the boiler

In coal-fuel fired boilers, a significant amount of energy is contained in

the bottom ash. In a wet bottom ash system, this energy is completely lost

because the ash is quenched. In the MAC™ System, the cooling air captures

the heat from the ash and provides oxygen for post-combustion resulting in:

•A substantial burn-out of remaining carbon in bottom ash

•Significant recovery of heat contained in the bottom ash. This heat recovery

reduces the heat and fuel losses from the boiler which can contribute increased

boiler efficiency

It is routinely demonstrated that the amount of cooling air used in the MAC™

System (typically less than one percent of total boiler combustion air) does not

have an adverse effect on the boiler operation

Delivery of dry ash

The bottom ash is delivered dry, which offers the following benefits:

•Simplified configuration of the downstream processing equipment

•After pulverization, dry low carbon content bottom ash can be mixed with

fly ash, leading to potential for increased ash sales revenues and simplified

ash management

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OPERATING CHARACTERISTICS

MAC™ is a trademark of Magaldi Power S.p.A.

Allen-Sherman-Hoff is a division of Diamond Power International, Inc.

MAC™ Systems are supplied in the United States by Allen-Sherman-Hoff under a license

from Magaldi Power S.p.A.

This information contain herein is solely for informational purposes and is not offered,

nor should be construed, as a warranty or contractual obligation. Diamond Power

International, Inc. Reserves the right to make design or material changes without notice.

©2005 Diamond Power International, Inc. All rights reserved. ASH-9342-0805-00

Magaldi Ash CoolerDry Bottom Ash System

www.a-s-h.com 1.888.ASH.PARTS

™

Field Evaluation ServicesAllen-Sherman-Hoff ’s team of engineers are available to perform an evaluation of your

existing bottom ash system to determine the benefits that may be realized by conversion

to a MAC™ System. For more information about the MAC™ System, please contact an

Allen-Sherman-Hoff representative at 1-888-ASH-PARTS.