JP3259831B2 - Method and apparatus for reburning unburned components in a gasifier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to coal, municipal solid waste,
Method and apparatus for reburning unburned matter (ash) when solid combustibles such as industrial waste are gasified in a fluidized bed, more specifically, large particle size unburned ash (mainly unburned) accumulated in a fluidized bed Carbon), and returns to the fluidized bed again to unify all unburned ash as scattered dust. It is.

[0002]

2. Description of the Related Art When gasifying solid combustibles such as coal and waste in a fluidized bed, the processing of unburned ash (mainly unburned carbon) determines the efficiency. Conventionally, in a fluidized bed furnace in which coal or waste is burned in a fluidized bed, unburned ash in a fluidized medium is extracted together with a fluidized medium, pulverized and re-introduced into a fluidized bed to increase the surface area of the unburned ash. There is known a technique for increasing the number of combustions in a fluidized bed (see, for example,
JP-83507, JP-A-3-213903,
JP-A-4-80512). Further, Japanese Unexamined Patent Publication No.
Japanese Patent No. 60847 discloses that waste containing chlorine compounds is incompletely burned in a fluidized bed furnace to partially convert the waste into char, and a combustible gas containing the char is introduced into a dust separator to separate the char. Then, the separated char is burned in a char combustion furnace to generate superheated steam.On the other hand, the large-grain char accumulated in the fluidized bed is extracted together with the large incombustible material, and the large incombustible material and the char are separated by a classifier. A fluidized bed refuse incinerator in which the classified char is supplied to a char combustion furnace and burned.

[0003]

The above-mentioned Japanese Patent Application Laid-Open No. 63-8 / 1988
In the conventional method described in JP-A-3507, JP-A-3-213903, and JP-A-4-80512, the combustion in the fluidized bed furnace is oxidative combustion, and the effect is not obtained under the condition that sufficient oxygen exists. However, under the condition of a low oxygen concentration, such as gasification combustion (combustion in a reducing atmosphere) in the present invention, unburned carbon is not sufficiently burned, so that the effect is small. In the fluidized bed refuse incinerator described in Japanese Patent Application Laid-Open No. 9-60847, the char supplied to the char combustion furnace is classified by a classifier into char as scattered dust separated by a dust separator. 2 with large grain char
It is a kind, and the transport and supply system of the char becomes two systems,
Driving operation becomes complicated. Further, since the two types of chars have different particle diameters and components, it is difficult to perform stable combustion processing.

[0004] In order to increase the combustion efficiency in a fluidized bed furnace, it is necessary to transfer unburned ash to a combustion section different from the combustion section of the fluidized bed and react it under different conditions. The unburned ash may carry over from the fluidized bed or be extracted from the fluidized bed.Therefore, if the large-sized unburned ash extracted from the fluidized bed is crushed and returned to the fluidized bed, all The unburned ash is collected as flying dust by a solid-gas separator, and can be unified and processed. The present invention has been made in view of the above points, and an object of the present invention is to supply a solid combustible to an unburned ash combustion furnace or an unburned ash melting furnace when gasifying a solid combustible in a gasification fluidized bed. Unburned ash can be used as one type, the particle size and components of unburned ash become uniform, stable combustion processing or melting processing becomes possible, and unburned ash in a gasification furnace can be improved in efficiency. An object of the present invention is to provide a minute reburning method and apparatus.

[0005]

In order to achieve the above object, a method for reburning unburned components in a gasifier according to the present invention comprises:
The solid combustibles are supplied to a gasification fluidized bed furnace to be gasified in a reducing atmosphere, and the unburned gas containing unburned ash is introduced from a freeboard into a solid-gas separator, where solid-gas separation is performed. The unburned ash is burned or melted in an unburned ash combustion furnace or unburned ash melting furnace and separated into solid and gas.
A method of the unburned gas Ru is burned in unburned gas combustion apparatus, the non-combusted ash-bed material discharge means with the fluidized medium non-combusted ash in the large particle size to be accumulated in the fluidized bed gasification fluidized bed furnace Yo
Ri extracted, withdrawn and returned to the fluidized layer by pulverizing a non-combusted ash and bed material of large particle size, and solid-gas separation is introduced into pulverized product the solid-gas separator from the freeboard along with unburned gases, all It is supplied to the non-combusted ash combustion furnace or not combusted ash melting furnace non-combusted ash as uniform scattering dust particle size and components combustion or
It is configured to perform unification processing by melting (see FIGS. 1 to 4). In this method, if solid combustibles contain incombustibles, after classifying the extractables from the fluidized bed to separate and remove large incombustibles from the sieve, uncombustible ash under the sieve and wherein the flow by crushing bed material
It is preferable to return to the layer (see FIGS. 2 and 4).

Further, the unburned portion reburning device in the gasification furnace of the present invention is connected to a gasification fluidized bed furnace for gasifying solid combustibles in a reducing atmosphere and a free board of the gasification fluidized bed furnace. and a solid-gas separator, comprises and either the non-combusted ash combustion furnace and the non-combusted ash melting furnace which is connected via a non-combusted ash conveying means in the lower portion of the solid-gas separator, the upper portion of the solid-gas separator Connection
In a solid combustible gasifier equipped with a burned unburned gas combustion device ,
Milling for grinding non-combusted ash in the accumulated large particle size are connected via a <br/> non-combusted ash-flowing medium discharging means for extracting with fluid medium, the non-combusted ash and fluidized medium having a large particle size And a pulverized material circulating supply means for connecting the pulverizer and the fluidized bed, and the pulverized material is returned to the fluidized bed and introduced into the solid-gas separator from the freeboard together with the unburned gas and solid-gas separated. All unburned ash is supplied to either unburned ash combustion furnace or unburned ash melting furnace as scattered dust with uniform particle size and composition for combustion
Alternatively, the unifying process is performed by melting (see FIGS. 1 to 4). In this apparatus, a classifier is provided upstream of the pulverizer connected to the unburned ash / fluid medium discharge means for separating / removing large incombustible substances contained in the unburnt ash / fluid medium as a sieve. ,Classification
Crush the unburned ash and fluid medium under the sieve
In some cases that make configuration back to the fluidized bed (see FIGS. 2 and 4).

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments and can be implemented with appropriate modifications. FIG. 1 shows an unburned portion reburning device in a gasifier according to a first embodiment of the present invention. Reference numeral 10 denotes a gasification fluidized bed furnace for gasifying solid combustibles,
A wind box 12 is provided at a lower portion, and a fluidized bed 16 is formed above the wind box 12 via an air distribution plate 14. As a fluid medium for forming the fluidized bed 16, sand (for example, silica sand) or the like is used. Reference numeral 18 denotes a free board (empty tower). A solid-gas separator 20 is connected to the free board 18 of the gasification fluidized-bed furnace 10. As the solid-gas separator 20, a dust collector such as a cyclone is used.
At the lower part of the solid-gas separator 20, unburned ash conveying means 22,
For example, an unburned ash combustion furnace or an unburned ash melting furnace 24 is connected via an unburned ash air transfer line. 26 is an unburned gas combustion device. Further, a pulverizer 30 is connected to the fluidized bed 16 of the gasification fluidized-bed furnace 10 via unburned ash / fluidized medium discharge means 28, for example, a screw type discharger. Crushed material circulating supply means 32,
For example, they are connected via a bucket conveyor or a pneumatic conveying line. As the crusher 30, a fine crusher such as a roll crusher, a vibration mill, and a ball mill is used. In addition, CaO, Ca (O (O)
H) _2, in some cases to introduce a desalting agent such as CaCO _3.

[0008] In the unburned portion reburning apparatus in the gasification furnace configured as described above, the solid combustible is supplied to the gasification fluidized bed furnace 10 and the air ratio is 0.15 to 0.95, preferably 0. Partial combustion (incomplete combustion) in a low oxygen state (reducing atmosphere) of 0.4 to 0.7 to gasify to generate unburned gas (combustible gas). The unburned gas containing unburned ash (mainly unburned carbon) of fine powder (10 to 500 μm) is introduced from the free board 18 into the solid-gas separator 20, where it is separated into unburned ash and unburned gas. The unburned ash is supplied to an unburned ash combustion furnace or an unburned ash melting furnace 24, where it is subjected to combustion processing or melting processing. On the other hand, the unburned gas is introduced into the unburned gas combustion device 26 and burned.

In the fluidized bed 16 of the gasification fluidized bed furnace 10,
Unburned ash with a large particle size (0.5 to 5 mm) (mainly unburned carbon)
The unburned ash having a large particle size is extracted together with the fluidized medium and pulverized to 10 to 500 μm by the pulverizer 30 to return the pulverized material to the fluidized bed 16. The pulverized material returned to the fluidized bed 16 is introduced into the solid-gas separator 20 from the free board 18 together with the unburned gas, and all unburned ash is unified as flying dust. The combustion temperature in the fluidized bed 16 is 450 to 700 ° C.

FIG. 2 shows an unburned portion reburning apparatus in a gasifier according to a second embodiment of the present invention. In the present embodiment, a classifier 34 such as a vibrating sieve is provided between the unburned ash / fluidized medium discharging means 28 and the crusher 30 so that the fluidized bed 16
After separating and removing large incombustible substances from the sieve, the unburned ash and the fluidized medium under the sieve are pulverized by the pulverizer 30. Classifier 34
Is preferably 0.5 to 1.0 cm.
Other configurations and operations are the same as those in the first embodiment.

FIG. 3 shows an unburned portion reburning device in a gasifier according to a third embodiment of the present invention. In the present embodiment, the unburned gas from the solid-gas separator 20 is introduced into the unburned gas combustion part 38 of the fluidized-bed combustion furnace 36 and burned in a fluidized bed. It is configured to be introduced into the unburned ash combustion part 40 of the bed combustion furnace 36 and perform fluidized bed combustion. 37 is a discharger and 39 is a blower. In the fluidized bed combustion furnace 36, the fluidized bed 42, the air distribution plate 44, and the wind box 46 are partitioned by a vertical partition member 48, and an unburned gas combustion section 38 and an unburned ash combustion section 40 are formed. . The partition member 48 has a length (height) at which the common free board 50 is formed. Then, the unburned gas combustion section 38
The superheater 52 is provided in the fluidized bed of the
The evaporator 54 is provided above the fluidized bed. In addition,
It is also possible to replace the superheater and the evaporator, provide a heat exchanger in the fluidized bed above the fluidized bed, or provide a heat exchanger above the fluidized bed in the fluidized bed. .
Other configurations and operations are the same as those in the first embodiment.

FIG. 4 shows an unburned portion reburning device in a gasifier according to a fourth embodiment of the present invention. In the present embodiment, a classifier 34 such as a vibrating sieve is provided between the unburned ash / fluidized medium discharging means 28 and the crusher 30 so that the fluidized bed 16
After separating and removing large incombustible substances from the sieve, the unburned ash and the fluidized medium under the sieve are pulverized by the pulverizer 30. Classifier 34
Is preferably 0.5 to 1.0 cm.
Other configurations and operations are the same as those in the third embodiment.

[0013]

As described above, the present invention has the following effects. (1) When gasifying solid combustibles in a gasification fluidized bed furnace, one type of unburned ash can be supplied to an unburned ash combustion furnace or an unburned ash melting furnace. For this reason, the particle diameter and components of the unburned ash become uniform, stable combustion processing or melting processing becomes possible, and efficiency can be improved. (2) It is possible to collect fly ash and unburned carbon in a fluid medium that have been conventionally discarded. (3) Since the unburned ash transport and supply system is one system, the driving operation is simplified.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an unburned portion reburning device in a gasifier according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing an unburned portion reburning device in a gasifier according to a second embodiment of the present invention.

FIG. 3 is a schematic configuration diagram showing an unburned portion reburning device in a gasifier according to a third embodiment of the present invention.

FIG. 4 is a schematic configuration diagram showing an unburned portion reburning device in a gasifier according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Gasification fluidized-bed furnace 12 Wind box 14 Air dispersion plate 16 Fluidized bed 18 Free board 20 Solid-gas separator 22 Unburned ash conveying means 24 Unburned ash combustion furnace or unburned ash melting furnace 26 Unburned gas combustion device 28 Not yet Combustion ash / fluid medium discharge means 30 Crusher 32 Crushed matter circulating supply means 34 Classifier 36 Fluidized bed combustion furnace 37 Discharger 38 Unburned gas combustion section 39 Blower 40 Unburned ash combustion section 42 Fluidized bed 44 Air dispersion plate 46 Wind Box 48 Partition member 50 Free board 52 Superheater 54 Evaporator

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiko Yoshii 1-3-1 Higashikawasaki-cho, Chuo-ku, Kobe Kawasaki Heavy Industries, Ltd. Kobe Head Office (56) References JP-A-63-65208 (JP, A) JP-A-8-338618 (JP, A) JP-A-8-52324 (JP, A) JP-A-9-303738 (JP, A) JP-A 9-112863 (JP, A) (58) Int.Cl. ⁷ , DB name) F23C 11/02 308 F23G 7/00 103

Claims (4)

(57) [Claims] 1. A solid combustible is supplied to a gasification fluidized bed furnace.
Gasify in a reducing atmosphere, introduce unburned gas containing unburned ash from the freeboard into the solid-gas separator, and burn the unburned ash separated by solid-gas in an unburned ash combustion furnace or unburned ash melting furnace. The unburned gas that has been melted and separated into solid and gas is burned with an unburned gas combustion device
In the method allowed Ru is, out unplug <br/> by non-combusted ash-bed material discharge means with the fluidized medium non-combusted ash in the large particle size to be accumulated in the fluidized bed gasification fluidized bed furnace, the extracted large The unburned ash having a diameter and the fluidized medium are pulverized and returned to the fluidized bed. The components are supplied to unburned ash combustion furnace or unburned ash melting furnace as uniform scattered dust and burned or melted.
A method for reburning unburned components in a gasifier, wherein the unburned portion is subjected to a unification treatment. 2. The method according to claim 1, wherein the extracted material from the fluidized bed is classified to separate and remove large incombustible substances on the sieve, and then the unburned ash and the fluidized medium under the sieve are pulverized and returned to the fluidized bed. 2. The method for reburning unburned components in the gasifier according to 1. 3. A gasification fluidized bed furnace for gasifying solid combustibles in a reducing atmosphere, a solid-gas separator connected to a free board of the gasification fluidized-bed furnace, and a solid-gas separator below the solid-gas separator. Either an unburned ash combustion furnace or an unburned ash melting furnace connected via unburned ash conveying means, and an unburned gas combustion device connected to the upper part of the solid-gas separator.
Equipped with a solid combustible gasifier, the large particles accumulated in the fluidized bed in the fluidized bed of the gasification fluidized bed furnace.
The non-combusted ash in diameter is connected via a non-combusted ash-flowing medium discharging means for extracting with fluid medium, wherein the flow and grinder for grinding non-combusted ash and fluidized medium having a large particle size, and the pulverizer And a pulverized material circulating supply means for connecting the pulverized material to the fluidized bed.The pulverized material is returned to the fluidized bed, introduced into the solid-gas separator from the freeboard together with the unburned gas, and solid-gas separated. Unburned ash in a gasification furnace, wherein the unburned ash is supplied to one of an unburned ash combustion furnace and an unburned ash melting furnace as a scattered dust having a uniform composition and burned or melted to be unified. Reburning device. 4. A classifier is provided upstream of the pulverizer connected to the unburned ash / fluid medium discharge means for separating / removing large incombustible substances contained in the unburnt ash / fluid medium as a sieve. Sieving of classifier
Pulverize the lower unburned ash and fluidized medium with a grinder and return to the fluidized bed.
The unburned part reburning apparatus for a gasifier according to claim 3, wherein