Classifications

• • 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 
  • F23J2900/00—Special arrangements for conducting or purifying combustion fumes; Treatment of fumes or ashes
  • F23J2900/01003—Ash crushing means associated with ash removal means
• • 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

• cooling ash on the offload conveyor and the subsequent conveyors is achieved by forced-convection heat exchange with air returning to the system once it has been pulled out by depression value occurring at the bottom of the furnace. Cooling air is introduced throughout suitable ports located at the sidewalls of the extractor and the subsequent conveyors and it runs over the ash while passing through the line of counter-flow conveyor machines until it reaches the combustion chamber.
• the system provides one or more milling stages between the extractor and the subsequent conveyor/cooler, as well as between two subsequent conveyors, in order to increase efficiency in air-ash heat exchanging. Such milling systems by reducing particle size of the ash increase available surface thereof for heat exchange with the counter-flow air.
• either the main extractor receiving ash from furnace either the subsequent conveyors are provided with fine ash recuperators located at the bottom. The recuperated ash is then unloaded together with heavy ash lumps on the next machine.
• the known system provides a by-pass duct with a suitable diameter connecting extractor top cover, in vicinity of unloading point, to the subsequent conveyor cover, in a position just downstream in respect of the unloading point.
• the aim is to allow a preferential path for the cooling air, while passing from a conveyor to the previous one, by starting it from the top of the ash conveyor belt.
• this solution reduces the ash cooling efficiency a lot, because only a minimum amount of air crosses the crusher where the heat-exchange efficiency is maximum due to opening of the ash flow falling in the crusher and to reduction of lump size achieved by crushing members that cause the available forced-convection heat-exchange surface of the ash to increase.
• the separation of the fine ash unloading is achieved forming a dedicated opening at the rear wall of the crusher, to which an unloading channel of the ash recuperating machine is connected and by isolating said unloading from crusher environment by means of a valve located in the unloading channel and a closing shield downstream of the traction head of the fine ash recuperator.
• the position of the fine ash entry to the crusher is such as to avoid pass through the milling zone for the fine ash and showing itself as a compact flow and any more dispersed in free fall, it results hardly entrainable by the cooling air crossing in counter-flow the crusher.
• the pre-crusher function is to execute a first milling of large ash lumps at high temperature that obstruct the crusher port, making the rotor teeth milling action faster and more efficient.
• the pre-crusher intervention is activated by a laser or equivalent sensor which senses the presence of incoming large ash lumps within milling area.
• Water for the cooling system is supplied preferably through the rotor axis and/or at the base of fixed slab and passes therefrom in the milling area through nozzles placed in the toothed rotor and/or in the fixed slab.
• Said cooling system is actuated by increase of the temperature values of the toothed roller and the crusher casing, detected by means of suitable sensors, and determined by presence of ash, or large agglomerates, at high temperature.
• the water flow rate to be supplied to the nozzles can be adjusted depending on temperature of the ash leaving the crusher and detected on the downstream machine by a suitable sensor. Steam occurring during cooling process, thanks to the separation of the crusher environment from the fine ash recuperator, will be dragged by the cooling air directly to the combustion chamber.
• Fig. 1 shows a cross-sectional view of the integrated milling and air/water cooling system.
• Fig. 2 shows a schematisation of positioning of the integrated milling and cooling system inside of the extraction and cooling air flow system throughout the system.
• Fig. 3 shows a milling and air/water cooling system axonometric projection.
• the milling and cooling system hereinafter described permits numerous and notable advantages because: it improves cooling air fluid dynamics with consequent removal of malfunctions and excessive wear for fine ash recuperating machines and crusher wear reduction, the efficiency of the heat exchange between air and ash is taken to the maximum since all the cooling air collides with the ash during falls between one conveyor machine and the next one and the cooling and milling process is optimised also for large ash lumps at high temperature further achieving a effective cooling of the crusher milling members.
• the system is constituted by a crusher 1 provided with a single, or dual, toothed roller 9, a pre-milling device 2, air 3 and water 4 cooling system and characterized by a side inlet 13 for fine material separate from lump sized ash inlet.
• the separate fine ash unloading 5, 6, 13 from the crusher 1 is formed by a suitable channel 14, independent from main ash unloading 16, connected to a suitable opening 13 formed in the rear wall of the crusher 1.
• the fine ash inlet position to the crusher 1 is such as to avoid it crossing the milling members 9.
• a counter-weight or automatic valve 5 allows discharge of fine material preventing air intake within the recuperator when it crosses the crusher counter-flow.
• a closing shield 6 placed downstream of the traction head 15 of the fine ash recuperator allows to isolate this zone from the conveyor machine unloading zone 16 and to remove air recurrences within the fine ash recuperator 15.
• the water cooling system 3-4 allows an additional cooling for large ash agglomerates at high temperature and it is operated depending on the rotor's 9 and casing's 11 temperature, detected by suitable sensors 12, which increases due to the presence of large lumps and/or ash high flow rate at high temperature in the milling area.
• the water cooling system 3-4 provides sprinkling nozzles 3 arranged preferably within the rotor 9 and/or the fixed slab 10.
• the water flow rate adjustment for the nozzles 3 is obtained depending on the temperature of the ash exiting the crusher 1 detected by a suitable sensor 19 on the machine downstream the crusher.
• the pre-crusher 2 is constituted by plates with punches 20 made by suitable anti- wear material, that slide opposing on a fixed frame 21 connected to the crusher's 1 port, and actuated by hydraulic cylinders 22.
• Such a device facilitates and speeds up actions of the rotor's 9 teeth of the crusher 1 when ash large lumps at high temperature obstruct inlet thereof, by moving and partially milling them by movement of the plates with punches 20.
• the pre-crusher's 2 intervention is controlled by a laser or equivalent sensor 7 which detects presence of ash large lumps in the milling area.
• the air and water cooling and milling system according to the present invention besides the huge functional advantage in improving cooling air fluid dynamics with consequent removal of obstructions and stoppages of the crusher 1 and the fine ash recuperators 15, provides a more comfortable and faster milling also of large ash agglomerates at high temperature, helping, by an indirect cooling of the milling members 9, in increasing the expected life of the crusher 1.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Crushing And Grinding (AREA)
• Processing Of Solid Wastes (AREA)
• Crushing And Pulverization Processes (AREA)
• Disintegrating Or Milling (AREA)
• Solid Fuels And Fuel-Associated Substances (AREA)
• Gasification And Melting Of Waste (AREA)

Applications Claiming Priority (2)

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• 2006
  • 2006-03-13 IT IT000437A patent/ITMI20060437A1/it unknown
• 2007
  • 2007-03-09 JP JP2008558694A patent/JP2009529416A/ja active Pending
  • 2007-03-09 CN CNA2007800134752A patent/CN101438101A/zh active Pending
  • 2007-03-09 AU AU2007224695A patent/AU2007224695A1/en not_active Abandoned
  • 2007-03-09 CA CA002645669A patent/CA2645669A1/en not_active Abandoned
  • 2007-03-09 KR KR1020087023497A patent/KR20090016546A/ko not_active Application Discontinuation
  • 2007-03-09 MX MX2008011726A patent/MX2008011726A/es not_active Application Discontinuation
  • 2007-03-09 WO PCT/EP2007/002123 patent/WO2007104502A1/en active Application Filing
  • 2007-03-09 US US12/225,050 patent/US20090173258A1/en not_active Abandoned
  • 2007-03-09 EP EP07723173A patent/EP2002182A1/en not_active Withdrawn
  • 2007-03-09 EA EA200801844A patent/EA014566B1/ru not_active IP Right Cessation
  • 2007-03-09 BR BRPI0709295-4A patent/BRPI0709295A2/pt not_active IP Right Cessation
• 2008
  • 2008-09-11 ZA ZA200807815A patent/ZA200807815B/xx unknown

Non-Patent Citations (1)

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