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.