Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23M—CASINGS, LININGS, WALLS OR DOORS SPECIALLY ADAPTED FOR COMBUSTION CHAMBERS, e.g. FIREBRIDGES; DEVICES FOR DEFLECTING AIR, FLAMES OR COMBUSTION PRODUCTS IN COMBUSTION CHAMBERS; SAFETY ARRANGEMENTS SPECIALLY ADAPTED FOR COMBUSTION APPARATUS; DETAILS OF COMBUSTION CHAMBERS, NOT OTHERWISE PROVIDED FOR
  • F23M20/00—Details of combustion chambers, not otherwise provided for, e.g. means for storing heat from flames
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
  • F23J1/00—Removing ash, clinker, or slag from combustion chambers
  • F23J1/02—Apparatus for removing ash, clinker, or slag from ash-pits, e.g. by employing trucks or conveyors, by employing suction devices
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
  • F23J2700/00—Ash removal, handling and treatment means; Ash and slag handling in pulverulent fuel furnaces; Ash removal means for incinerators
  • F23J2700/001—Ash removal, handling and treatment means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
  • F23J2700/00—Ash removal, handling and treatment means; Ash and slag handling in pulverulent fuel furnaces; Ash removal means for incinerators
  • F23J2700/003—Ash removal means for incinerators
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
  • F23J2900/00—Special arrangements for conducting or purifying combustion fumes; Treatment of fumes or ashes
  • F23J2900/01005—Mixing water to ash

Definitions

• the cooling of the ash on the extractor conveyor and on the subsequent conveyors is achieved by the thermal exchange by forced convection with air returning inside the system sucked up by the depression value being at the furnace bottom.
• the cooling air returns through suitable intakes placed on the sidewalls of the extractor and the subsequent conveyors and runs over the ash counter-flow passing through the line of the transport machines till it reaches the combustion chamber.
• the operating mode of the known extraction system provides the power to close the valves at the furnace bottom and store the ash within the hopper. This operation allows an optimum flexibility of the system permitting to carry out the maintenance operations.
• the ash begins to settle on the bottom valves and first, when the ash height is not high yet, the cooling air can pass into the hopper cooling both the ash just settled, passing through the material bed, and the free falling ash, crossing it in counter-flow. While the ash height increases above the bottom valves, the air incurs higher and higher drag on entering the hopper, the air amount is smaller and smaller till it fully adopts itself.
• the ash amount at high temperature discharging onto the extractor during the opening of the bottom valves is such that it cannot be cooled by the system counter-flow air and this causes forward wearing problems and malfunctions due to local deformations particularly on the milling members downstream of the extractor.
• the cooling effect from the entering air is enhanced by addition of water through nozzles placed either on the hopper sidewalls or in the hopper air intakes.
• the position of the air intakes and nozzles is such that free entry of air is assured even in case of ash stored up to the maximum height expected.
• the resulting steam returns the furnace sucked up by the depression being therein and helps for a further cooling crossing the counter- flow falling ash.
• the water amount to be sent to the nozzles is finely adjusted based on ash temperature and flow rate values shown by suitable sensors, such that it helps suitably the cooling without humidifying it.
• Fig. 1 is side view of the ash extractor provided with air intakes on the sidewall of the storing hopper connected by means of valve to the extractor environment.
• Fig. 2 is a top view of the intakes at the storing hopper and of the connection to the extractor environment.
• Fig. 3 is a cross-sectional view of the extractor at the storing hopper pointing out the presence of the cooling water supply nozzles.
• Fig. 5 is a cross-sectional view of the extractor at the storing hopper pointing out the presence of the cooling water supply nozzles placed into the side entries.
• the ash cooling system allows, during the ash storing step at the hopper (1), for cooling ash while falling through the relief of the furnace (12) by means of a system with side entries (2). Since the air distributing chute (3) is connected directly to the extractor (6), the air entry from the environment occurs through the same side intakes (4) used during the normal operation step. Thus, the air amount used for the cooling is always the same during either continuous operation or storing step.
• the extra air intakes (2) are placed on the sidewall of the hopper (1) at height being over the maximum height of the ash storable onto the bottom valves (5), such that obstructions and malfunctions of the intakes (2) due to the great ash height can be avoided.
• Such air intakes (2) are supplied for each side of the hopper (1) by a single chute (3) connected to the lid (7) of the extractor (6) by means of either manual or automatic valve (8).
• a single chute (3) connected to the lid (7) of the extractor (6) by means of either manual or automatic valve (8).
• Opening of the valve (8) is operated simply by closing of the bottom valves (5).
• the air sucked from outside through the side intakes (4) enters the extractor (6), and not being able to enter the furnace since the bottom valves (5) are closed, is constrained to go toward the chute (3).
• the bottom valves (5) are not airtight, as a result a certain amount of the air will keep passing through the bottom, till the stored ash layer onto the valves (5) closes fully the passage.
• the use of the ash cooling system during the storing step is useful also in plant configurations that provide an extractor slope greater than natural declivity angle of the conveyed material. In such a case, during the extraction step at curve, some ash stores may occur in connection with landslides of the material on the leaning stretch.
• This mode of air inflow into the furnace has outstanding advantages relative to the cooling of the stored ash due to a more uniform air distribution over the whole passage surface of the falling ash, with no need to increase the amount of air entering the furnace.
• a further configuration of the cooling system at the hopper provides use of cooling water (14) through nozzles suitably placed inside the hopper which helps in cooling the ash stored on the bottom valves (5), running over it after having been finely dosed in order to cool but not to humidify the ash.
• the water amount supplied to the nozzles is, indeed, adjusted based on the temperature and flow rate values of the stored ash, measured by suitable sensors (not shown) placed inside the hopper.
• the steam output during the water cooling is sucked up by the depression at the furnace and is mixed with the combustion smoke and thus adds further cooling of the ash falling from the combustion chamber.
• Such a further expedient results as an important contribution for the ash cooling process since it takes advantage of the water latent heat of vaporization which subtracts heat from the ash stored at the hopper, but leaving dry the ash recovered from the hopper bottom by the known extraction system.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Gasification And Melting Of Waste (AREA)
• Vertical, Hearth, Or Arc Furnaces (AREA)
• Furnace Details (AREA)
• Processing Of Solid Wastes (AREA)
• Solid Fuels And Fuel-Associated Substances (AREA)

Priority Applications (10)

Applications Claiming Priority (2)

Publications (1)

Family

ID=38474061

Family Applications (1)

Country Status (14)

Cited By (3)

Families Citing this family (9)

Citations (3)

Family Cites Families (9)

• 2006
  • 2006-05-23 IT IT001010A patent/ITMI20061010A1/it unknown
• 2007
  • 2007-05-21 PL PL07725542T patent/PL2032899T3/pl unknown
  • 2007-05-21 WO PCT/EP2007/004646 patent/WO2007134874A1/en not_active Ceased
  • 2007-05-21 EA EA200802183A patent/EA012796B1/ru not_active IP Right Cessation
  • 2007-05-21 JP JP2009511418A patent/JP5558098B2/ja active Active
  • 2007-05-21 CN CN2007800255780A patent/CN101484754B/zh not_active Expired - Fee Related
  • 2007-05-21 BR BRPI0711202-5A patent/BRPI0711202A2/pt not_active Application Discontinuation
  • 2007-05-21 AU AU2007253584A patent/AU2007253584B2/en not_active Ceased
  • 2007-05-21 KR KR1020087029541A patent/KR101469003B1/ko active Active
  • 2007-05-21 MX MX2008014867A patent/MX2008014867A/es active IP Right Grant
  • 2007-05-21 EP EP07725542.0A patent/EP2032899B1/en active Active
  • 2007-05-21 US US12/227,585 patent/US8833277B2/en active Active
  • 2007-05-21 CA CA002653006A patent/CA2653006A1/en not_active Abandoned
• 2008
  • 2008-11-21 ZA ZA200809940A patent/ZA200809940B/xx unknown

Patent Citations (3)

Also Published As

Similar Documents

Legal Events