US 5,858,033 AGranted

Method of and apparatus for fluidized-bed gasification and melt combustion

AssigneeEbara Corporation

InventorsYoshio Hirayama, Takahiro Oshita, Chikashi Tame, Shuichi Nagato, Tetsuhisa Hirose, Norihisa Miyoshi, Seiichiro Toyoda, Shugo Hosoda, Shosaku Fujinami, Kazuo Takano

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Abstract

A combustion method and apparatus in which combustible matter, e.g., waste matter, coal, etc., is gasified to produce a combustible gas containing a sufficiently large amount of combustible component to melt ash by its own heat. A fluidized-bed furnace has an approximately circular horizontal cross-sectional configuration. A moving bed, in which a fluidized medium settles and diffuses, is formed in the central portion of the furnace, and a fluidized bed, in which the fluidized medium is actively fluidized, is formed in the peripheral portion in the furnace. The fluidized medium is turned over to the upper part of the moving bed from the upper part of the fluidized bed, thus circulating through the two beds. Combustible matter is cast into the upper part of the moving bed and gasified to form a combustible gas while circulating, together with the fluidized medium. The amount of oxygen supplied to the fluidized-bed furnace is set so as to be not higher than 30% of the theoretical amount of oxygen required for combustion. The temperature of the fluidized bed is maintained at 450.degree. C. to 650.degree. C. so that the combustible gas produced contains a large amount of combustible component. The combustible gas and fine particles produced in the fluidized-bed furnace are supplied to a melt combustion furnace where they are burned at high temperature, and the resulting ash is melted.

Claims36

Dependent claims

A method of processing combustible material containing incombustible matter, said method comprising:

providing a fluidized bed of fluidized medium within a fluidized-bed reactor by supplying thereto an upward flow of fluidizing gas;
creating within said fluidized bed a circulating flow of said fluidized medium within said reactor by causing said upward flow of fluidizing gas to a first area of said bed to be of a greater mass velocity than to a second area of said bed, whereby said fluidized medium moves upwardly in said first area of said bed as an oxidization zone, and said fluidized medium moves downwardly in said second area of said bed as a gasification zone;
introducing a supply of said combustible material to be processed onto said fluidized bed such that said combustible material moves downwardly with said fluidized medium in said second area of said bed, thereby gasifying said combustible material in said gasification zone and generating combustible gas and char, and such that said char moves upwardly with said fluidized medium in said first area of said bed and is partially oxidized in said oxidization zone to form char particles;
discharging through an outlet said incombustible matter contained in said supply of combustible material and fluidized medium from said reactor, separating the thus discharged fluidized medium from said incombustible matter, and returning the thus separated fluidized medium to said bed in said reactor;
preventing said combustible gas from discharging through said outlet;
discharging said combustible gas and char particles together from said reactor and introducing the thus discharged combustible gas and char particles together into a high temperature furnace;
combusting said combustible gas and said char particles at a temperature of at least 1300.degree. C. within said furnace and thereby decomposing harmful substances and melting resultant ash;
and
discharging the thus melted ash as molten slag.

6 more elements

An apparatus for processing combustible material containing incombustible matter, said apparatus comprising:

a fluidized-bed reactor having therein a bed of fluidized medium;
means for creating within said fluidized bed a circulating flow of said fluidized medium within said reactor by causing said upward flow of fluidizing gas to a first area of said bed to be of a greater mass velocity than to a second area of said bed, whereby said fluidized medium moves upwardly in said first area of said bed as an oxidization zone, and said fluidized medium moves downwardly in said second area of said bed as a gasification zone;
means for introducing a supply of the combustible material to be processed onto said fluidized bed such that the combustible material moves downwardly with said fluidized medium in said second area of said bed, thereby gasifying the combustible material in said gasification zone and generating combustible gas and char, and such that the char moves upwardly with said fluidized medium in said first area of said bed and is partially oxidized in said oxidization zone to form char particles;
means for discharging through an outlet the incombustible matter contained in the supply of combustible material and fluidized medium from said reactor, separating the thus discharged fluidized medium from the incombustible matter, and returning the thus separated fluidized medium to said bed in said reactor;
means for preventing the combustible gas from discharging through said outlet;
a high temperature furnace operable at a temperature of at least 1300.degree. C.;
means for discharging the combustible gas and char particles together from said reactor and introducing the thus discharged combustible gas and char particles together into said high temperature furnace, thus combusting the combustible gas and char particles at said temperature of at least 1300.degree. C. and thereby decomposing harmful substances and melting resultant ash;
and
means for discharging the thus melted ash as molten slag.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/915,322Filed 20 Aug 1997 · division
Priority: JP 6-6543910 Mar 1994
Granted: 12 Jan 1999
Term ends: Not estimatedThe source records don’t support an estimate.

Classification61 codes

C10J 3/723
Other features: controlling or regulating the gasification process
C10J 3/503
Fuel charging devices: for gasifiers with stationary fluidised bed
C10J 3/523
Ash-removing devices: for gasifiers with stationary fluidised bed
C10J 3/54
Gasification of granular or pulverulent flues in suspension: gasification of granular or pulverulent fuels by the Winkler technique, i.e. by…

Family

Serial401,370Parent of this division · filed 9 Mar 1995
Serial547,126Parent of this division · filed 24 Oct 1995
US 5,725,614 AParent of this division
US 5,620,488 AParent of this division
US 5,858,033 AThis patent

From the US filing history. Foreign family members aren’t listed.