Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
  • F23G5/44—Details; Accessories
  • F23G5/48—Preventing corrosion
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
  • F23C10/00—Fluidised bed combustion apparatus
  • F23C10/02—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed
  • F23C10/04—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone
  • F23C10/08—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone characterised by the arrangement of separation apparatus, e.g. cyclones, for separating particles from the flue gases
  • F23C10/10—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone characterised by the arrangement of separation apparatus, e.g. cyclones, for separating particles from the flue gases the separation apparatus being located outside the combustion chamber
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
  • F23G5/30—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having a fluidised bed
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
  • F23C2206/00—Fluidised bed combustion
  • F23C2206/10—Circulating fluidised bed
  • F23C2206/103—Cooling recirculating particles
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G2203/00—Furnace arrangements
  • F23G2203/50—Fluidised bed furnace
  • F23G2203/501—Fluidised bed furnace with external recirculation of entrained bed material

Definitions

• the invention relates to a method for burning or gasifying combustible material containing material in the circulating fluidized bed, a swirl chamber for combustion or gasification, a solid separator connected to the upper region of the swirl chamber, a return of solids accumulating in the solid separator to the swirl chamber and a cooling device for indirect cooling of solids that come from the solids separator, the cooling device containing a plurality of fluidized beds that are traversed by the solids one after the other.
• a method of this type is known from WO 97/46829 AI.
• the cooling device is an uncooled fluidized bed upstream, the exhaust gases of which are fed directly into the combustion. This measure is intended to reduce the chloride concentration in the solids to be cooled.
• the chlorides are responsible for aggressive corrosion attacks on the cooling devices.
• the known blowing through of the fluidized bed, especially in unfavorable cases, is not suitable for reducing the chloride concentration in the solids to be cooled sufficiently to ensure the desired protection against corrosion.
• the invention has for its object to treat the hot solids coming from the solids separator so that their corrosiveness in the cooling device disappears completely or almost. According to the invention, this is achieved in the process mentioned at the outset in that the first fluidized bed, into which the hot solids coming from the solids separator are first led, is located in a dechlorination chamber, the fluidization gas being in the dechlorination chamber at temperatures of the solids in the range from 700 to 1100.degree and at least one of the dechlorination additives
• Various aluminum silicates e.g. B. proven kaolinite.
• Activated silicates e.g. commercially available ICA 5000 are also very suitable.
• B. is achieved by boiling in sodium hydroxide solution. You can also use waste materials inexpensively, e.g. B. chloride-free sewage sludge or contaminated soil in which these additives are contained.
• the reactivity of the silicates, aluminum silicates or the activated silicates is essentially based on the hydroxyl groups on the silicon.
• These additives bind the alkalis and metals in the hot solids, so that chlorine is released as HC1, which is less corrosive than z.
• These solid additives are usually added to the fluidized bed in powder form, the mean grain sizes d * o being approximately in the range from 50 to 500 ⁇ m. It is also possible for the solid additives to be introduced early into the hot solid feed line.
• Gaseous S0 2 is particularly suitable for reacting with vaporous alkali chloride or metal chloride and thereby forming sulfates and HCl in the presence of molecular oxygen.
• the released HC1 is driven out of the dechlorination chamber with the fluidizing gas.
• Sulphates are not or hardly corrosive and can with the ash removed from the process z. B. be deposited.
• the S0 2 may also be introduced by sulfur-containing materials, which release at the high temperatures in the dechlorination chamber S0 2 or S0 release in an oxidizing atmosphere. 2
• the fluidized bed in the dechlorination chamber can work with or without indirect cooling; Usually this fluidized bed will be kept free from indirect cooling.
• the remaining fluidized beds in the cooling device contain heat exchangers through which liquid, gaseous or vaporous coolants flow. By removing or at least reducing the corrosiveness of the hot solids, you can keep the temperature in the hottest fluidized bed high, which z. B. steam overheating benefits.
• the material to be burned or gasified can be of different types.
• the material to be burned or gasified is fed through the line (1) into the fluidized bed (2), which belongs to a circulating fluidized bed. With the upper area of the swirl chamber (2) is therefore through the channel (3) Solid separator (4) connected, which is z. B. is a cyclone. Partially dedusted gas is drawn off in line (5) and it will be fed to a cooling and cleaning unit, not shown, which is known per se. Part of the solids accumulating in the separator (4) is fed back into the swirl chamber (2) through the return line (6) via a siphon (7). The flow in the siphon is controlled by a fluidizing gas flow which is introduced in line (7a).
• the swirl chamber (2) In the lower area of the swirl chamber (2) there is a grate (8) from which oxygen-containing fluidizing gas flows upwards into the chamber.
• the fluidizing gas comes from the line (9) and first enters a distribution chamber (10) before it flows through the grate (8). Ash is removed from the chamber (2) through the extractor (11).
• the material to be burned or gasified can be various types of granular solids with flammable constituents, and liquid or pasty substances can also be added.
• the temperatures in the swirl chamber (2) are usually in the range from 700 to 1100 ° C and preferably 800 to 1050 ° C. Due to the fluidizing gas, part of the solids is constantly led through the channel (3) to the separator (4).
• the amount of solids that is returned through the return line (6) to the swirl chamber (2) is usually at least 5 times the amount of solids per hour that is in the swirl chamber (2) on average.
• the cooling device (15) has a dechlorination chamber (16) and three cooling chambers (16a), (16b) and (16c).
• the cooling chambers contain heat exchangers (17) and (18) for indirect cooling of the solids, which are there as fluidized beds (21), (22) and (23).
• Weir-like chamber walls (21a), (22a) and (23a) are located between the beds, fluidizing gas is supplied through lines (21b), (22b) and (23b).
• the fluidizing gas can e.g. B. is air.
• the dechlorination chamber (16) has a feed line (20a) for fluidizing gas (e.g. air), the gas of which flows through a grate (20b) into a fluidized bed (20) and then first into the gas space above the fluidized bed (20) (25) arrives.
• a gas space is also located above the other fluidized beds (21), (22) and (23).
• the gas is discharged through a manifold (26) which opens into the swirl chamber (2) and also carries the exhaust gas of the cooled fluidized beds (21), (22) and (23) with it.
• the dechlorination chamber (16) can have its own gas discharge line (26a), which is shown in broken lines.
• the dechlorination chamber (16) is provided with a supply line (27) for solid additives and with a supply line (28) for gaseous additives.
• the gaseous additives can also be supplied in whole or in part through line (28a).
• Solid additives are silicates, aluminum silicates and / or activated silicates or mixtures which contain at least one of these additives.
• the gaseous additive used is gaseous SO 2 or other sulfur-containing materials which release SO 2 in an oxidizing atmosphere. It is important that the content of alkali and metal chlorides, which are brought in with the hot solids through line (14), is largely reduced by the additives.
• the solids which leave the dechlorination chamber (16) via the weir-like wall (21a) and pass into the fluidized bed (21) have at most 20% of the alkali metal and metal chloride content present in the solids of the line ( 14) is present.
• the cooled solids which have partially given up their heat in the cooling device (15), wherein as a coolant z. B. boiler feed water or steam are used through the line (30) back into the swirl chamber (2). Some of the cooled solids can also be removed from the process, which is not shown in the drawing.
• a mixture of 121,000 kg of granular coal and 41,000 kg of straw is heated at one temperature in the swirl chamber (2) burned from 850 ° C. 16200 kg / h of ash with a chlorine content of 0.002% by weight are passed through line (14) into the dechlorination chamber (16), which has a base area of 1.5 ⁇ 0.8 m and a height of 1.6 m .
• the height of the fluidized bed (20) is 1 m.
• the chamber (16) is fed as a solid additive of 23 kg / h of the activated silicate ICA 2000 (manufacturer: ICA Chemie, A-3384 Gross-Sierning) and as a gaseous additive S0 2 through lines (27) and (28) , a concentration of 30 ppm S0 2 being established in the gas space (25).
• the ash cooled to 720 ° C. is drawn off through line (30) and led back into the swirl chamber (2).
• the treatment in the dechlorination chamber (16) reduces the chlorine content in the solids to 10% of the initial content.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Treating Waste Gases (AREA)
• Gasification And Melting Of Waste (AREA)
• Fluidized-Bed Combustion And Resonant Combustion (AREA)
• Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
• Processing Of Solid Wastes (AREA)
• Chimneys And Flues (AREA)
• Incineration Of Waste (AREA)
• Hydrogen, Water And Hydrids (AREA)

Priority Applications (9)

Applications Claiming Priority (2)

Publications (1)

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Citations (5)

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• 1999
  • 1999-01-29 DE DE19903510A patent/DE19903510C2/de not_active Expired - Fee Related
  • 1999-12-03 TW TW088116206A patent/TW414844B/zh not_active IP Right Cessation
• 2000
  • 2000-01-19 AT AT00901114T patent/ATE227825T1/de active
  • 2000-01-19 PT PT00901114T patent/PT1068475E/pt unknown
  • 2000-01-19 DK DK00901114T patent/DK1068475T3/da active
  • 2000-01-19 JP JP2000596309A patent/JP4443769B2/ja not_active Expired - Fee Related
  • 2000-01-19 US US09/647,630 patent/US6649135B1/en not_active Expired - Lifetime
  • 2000-01-19 WO PCT/EP2000/000378 patent/WO2000045091A1/de not_active Ceased
  • 2000-01-19 ES ES00901114T patent/ES2185559T3/es not_active Expired - Lifetime
  • 2000-01-19 AU AU21094/00A patent/AU763820B2/en not_active Ceased
  • 2000-01-19 PL PL343119A patent/PL191977B1/pl unknown
  • 2000-01-19 EP EP00901114A patent/EP1068475B1/de not_active Expired - Lifetime
  • 2000-01-19 CZ CZ20003568A patent/CZ297653B6/cs not_active IP Right Cessation
  • 2000-01-19 HU HU0102841A patent/HU222149B1/hu not_active IP Right Cessation
  • 2000-01-19 DE DE50000746T patent/DE50000746D1/de not_active Expired - Lifetime

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