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
  • F23G5/08—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having supplementary heating
  • F23G5/14—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having supplementary heating including secondary combustion
  • F23G5/16—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having supplementary heating including secondary combustion in a separate 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
  • F23G5/20—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having rotating or oscillating drums
• • 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
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G7/00—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals
  • F23G7/001—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals for sludges or waste products from water treatment installations

Definitions

• the present invention relates to a method of incinerating waste material, said method being of the kind set forth in the preamble of claim 1.
• a rotary kiln is used for the second combustion zone
• an ash-burning vibratory conveyor constitutes the main component of the second combustion zone
• the first combustion zone is used to carry out an amount of incineration work per unit time below and up to a maximum determined by its capacity
• the second zone is used to deal with peak loads beyond the capacity of the first zone
• An ash-burning vibratory conveyor is probably considerably less costly and more adaptable than a rotary kiln, but - like the latter - it suffers from the disadvantage of having moving mechanical parts subjected to high temperatures.
• the fluidizing gas may be used as a vehicle for effecting adjustments of the combustion process taking place in the second combustion zone. It is e.g. possible to vary the intensity of combustion by varying the volume per unit time of the fluidizing gas and /or its composition by varying the percentage of e.g. oxygen, carbon dioxide or nitrogen.
• Another advantage of a fluidized-bed furnace is that - at least in principle - it comprises no moving parts with the exception of the particles of the fluidized bed itself, and it can also be constructed at a relatively low cost as compared to a vibratory ash-burning conveyor and - not least - a rotary kiln.
• the present invention also relates to an incinerator for carrying out the method of the invention.
• This incinerator is of the kind set forth in the preamble of claim 8, and according to the invention it also comprises the features set forth in the characterizing clause of this claim 8.
• Figure 1 is an overall view of the incinerator, taken mostly as a longitudinal vertical section, Figure 2 at an enlarged scale shows an important furnace component of the incinerator shown in Figure 1 , and
• Figure 3 is an overall view, taken in the same manner as Figure 1 , but showing an altered embodiment.
• the incinerator shown in Figures 1 and 2 comprises the following well-known components: - an inlet chute 1, through which waste material to be incinerated (not shown) is introduced, and the lower end of which, possibily through infeed means
• furnace chamber 2 (not shown), opens into a furnace chamber 2, the bottom of which is constituted by a grate 3 for supporting the waste material being incinerated during the combustion process, said furnace chamber 2 opening into a boiler 4 for extracting heat from the flue gas received from the furnace chamber 2, and finally a flue-gas cleaner 5 for removing dust, noxious gases and other components from the flue gas received from the boiler 4.
• the boiler 4 and the flue-gas cleaner 5 are shown in "block-diagram" form, as they can be constructed in any suitable manner, known or unknown, to fulfil their functions. 4
• the problem referred to above is solved by, in addition to the first combustion zone represented by the space above the grate 3, providing a second combustion zone.
• previous incinerators have comprised rotary kilns or ash- burning vibratory conveyors as active parts of the second combustion zone.
• the active component of this second zone is constituted by a fluidized-bed furnace 6, preferably of the type comprising a body of sand or similar refractory particulate material constantly agitated by suitable means (not shown), such as jets of gas that may be heated or combustible to produce heat within the furnace 6.
• the sand in the fluidized-bed furnace 6 is not only being constantly agitated by fluidizing gas, that may be air, through a plenum 17 and the perforated bottom of the furnace 6, but is also preferably kept in constant circulation by e.g. a lifting conveyor 18, partly through the fluidized bed itself, partly through a separator 7 having an outlet 8 for ashes and/or slag, the sand being returned to the bed.
• fluidizing gas that may be air
• the grate droppings are conveyed in a downstream direction to the fluidized-bed furnace 6 by means of a conveyor, in the exemplary embodiment shown as a worm conveyor 10, but other types of conveyors could, of course, be used, such as grate-belt conveyors, scraper conveyors, of the dry or wet type, or simply an inclined chute or skid.
• a conveyor in the exemplary embodiment shown as a worm conveyor 10, but other types of conveyors could, of course, be used, such as grate-belt conveyors, scraper conveyors, of the dry or wet type, or simply an inclined chute or skid.
• the incinerator shown in Figure 1 comprises a number of auxiliary inlets, i.e. a first auxiliary inlet 11 leading into the side of the inlet chute 1 at some distance below its top, - a second auxiliary inlet 12 leading into the furnace chamber 2 in the roof or in the side wall above the grate 3, and a third auxiliary inlet 13 leading into the space above and placed vertically above the fluidized-bed furnace 6.
• the first, second and third auxiliary inlets 11 , 12 and 13, respectively, are mainly intended for the introduction of sludge, such as sewage sludge, into the incinerator. Which of these three auxiliary inlets to choose for this purpose will in each case depend on the operating conditions, such as the quality and quantity of the "normal" waste material being introduced to the inlet chute, as well as on the 6
• the temperature on the grate 3 is very high, the heat present here can be exploited to evaporate water from sludge being introduced through the second auxiliary inlet 12, at the same time lowering the temperature to an acceptable operating level.
• the third auxiliary inlet 13 in relation to the fluidized-bed furnace 6.
• the second auxiliary inlet 12 may be used for introducing waste material that for some reason or other is considered unsuitable for feeding through the chute 1.
• waste material could comprise waste material from hospitals etc., as well as sludge of various types.
• the exemplary embodiment shown in Figure 3 uses a rotary kiln 14 as the active part of the first combustion zone.
• a rotary kiln 14 instead of the furnace chamber 2 of Figure 1 with the grate 3 and the space 9 with the conveyor
• this problem can be avoided by providing the flue-gas cleaner 5 with an exhaust fan 15 adapted to keep the pressure in the spaces upstream of it below atmospheric.
• the cleaner 5 also comprises an outlet 16 for dust separated from the flue gas.
• the first and second combustion systems in combination can be fed with a full variety of municipal and industrial waste types, e.g. completely filled waste bags, solid waste of similar bulk size, shredded waste, sludges, hospital waste, waste oil and bio-fuels, and at the same time it can be ensured that the slag and/or ashes 7

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Gasification And Melting Of Waste (AREA)
• Fluidized-Bed Combustion And Resonant Combustion (AREA)
• Processing Of Solid Wastes (AREA)
• Fertilizers (AREA)
• Incineration Of Waste (AREA)

Applications Claiming Priority (1)

Publications (2)

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ID=8156461

Family Applications (1)

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Cited By (1)

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• 1998
  • 1998-03-23 EP EP98914835A patent/EP1066486B1/de not_active Expired - Lifetime
  • 1998-03-23 WO PCT/DK1998/000112 patent/WO1999049265A1/en active IP Right Grant
  • 1998-03-23 AT AT98914835T patent/ATE219829T1/de not_active IP Right Cessation
  • 1998-03-23 DE DE69806273T patent/DE69806273T2/de not_active Expired - Lifetime
  • 1998-03-23 DK DK98914835T patent/DK1066486T3/da active
  • 1998-03-23 AU AU69180/98A patent/AU6918098A/en not_active Abandoned

Non-Patent Citations (1)

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