JPS60101410A - Fluidized-bed combustion device - Google Patents

Abstract

PURPOSE:To sharply improve combustion efficiency, by a method wherein solid fuel is classified into a massive substance and a granular substance according to a grain size to feed them, and the air for combustion is regulated. CONSTITUTION:A fluidized bed is vertically partitioned by a partition wall 13, formed with a water cooling wall pipe, refractory and the like, to form two beds, the one being a wide bed 19 and the other being a narrwo bed 20. A granular substance 3 in solid fuel and a powdery solid substance 6, in which an unburnt substance 5 collected by a cyclone 17 is mixed, are fed to the lower part of the narrow bed 20 by means of a powdery solid matter 6, in which an unburnt substance 5 collected by a cyclone 17 is mixed, are fed to the lower part of the narrow bed 20 by means of a powdery substance feeder 15. A massive substance feed port 27 with a built-in spreading device 9, which flies a massive substance 2 in the solid fuel to scatter it over the fluidized bed, is formed above the powdery substance feed port 26 to feed the massive substance therethrough. A partition 11 is located in a wind box 10 and on the extension line of the partition wall 13 in the fluidized bed 14 to divided the wind box, and the air 7 for combustion to the narrow bed 20 is regulated through installation of a regulating damper 12 to the partition 11. This enables the massive substance to be brought into a fluid state even if it is large and prevents the fine powdery substance from flying, resulting sharp improvement of combustion efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluidized bed combustion apparatus that burns solid fuel while fluidizing it.

To explain a conventional example of a fluidized bed combustion apparatus, in FIG. 1, coal,
A fuel 01 such as oil coke or wood chips is rotated and supplied by a sprayer 07 that prevents the solid matter of the fuel from flying away, and the combustion air 02 is passed through a wind box O6 to form a perforated plate and dispersed. Fuel O is supplied into the fluidized bed through the holes in the plate 05.
Combustion is performed by forming a fluidized bed 04 in which J is fluidized.

However, in the conventional combustion apparatus described above, solid fuel with a wide particle size distribution is burned in one fluidized bed 04, so the combustion efficiency decreases due to the scattering of powdery substances in the fuel. In addition, the spreader 07 prevents lumps from flying away, but since it has the property of causing powdery materials to fall toward you, uniform fluidization of the solid fuel may be hindered, further reducing the furnace load. Furthermore, even fuel f!4o1, whose particle size can be adjusted, has the disadvantage that it may become powdered during transportation, which causes a reduction in combustion efficiency.

This invention was made in order to eliminate such drawbacks of conventional combustion equipment, and among the solid fuel lumps and powder that have been separated in advance, the lumps are removed from the fluidized bed using a scatterer. At the same time, the powder is supplied into the fluidized bed together with the unburned solids collected from the exhaust gas, and the fluidized bed is equipped with a partition made of a water-cooled pipe or the like with one side wide (and the other side narrow). The powder material is supplied to the narrow side of the air box, and the scatterer is placed above it, and the air for combustion is fed into the fluidized bed on the narrow side. The object of the present invention is to provide a fluidized bed combustion apparatus in which combustion efficiency is significantly improved by installing a flow rate regulating damper that can freely adjust the air volume.

Next, to explain the drawings showing the embodiments of the present invention, in FIGS. 2 and 3, exhaust gas 4 is discharged to the upper part of the combustion furnace 8 and the exhaust gas is sent to the cyclone 17 for collecting unburned materials. A gas port 24 is disposed, and an air flow port 25 is installed at the lower part of the combustion furnace to send and store combustion air 7 to a wind box 10, which will be described later, and which is arranged at the lower side of the combustion furnace. At the top of the wind box, there is a dispersion plate 21 made of a perforated plate.
A fluidized bed is placed above the solid fuel 1 consisting of coal, oil coke, wood chips, etc. with a particle size distribution of usually less than 30 g in a fluidized medium such as sand, limestone, ash, etc., and fluidized combustion is carried out. 14 to send the combustion air into the fluidized bed through a dispersion plate, and the fluidized bed is further connected to a water-cooled wall tube,
It is vertically divided by a partition wall 13 made of refractory material or the like to form a wide layer 19 on one side and a narrow layer 20 on the other side, and an evaporation pipe 22 for vaporizing water is installed horizontally in both layers. It is connected to a heat exchanger tube of a boiler (not shown), and the narrow layer 20
A powder supply device such as a screw feeder, a table feeder, etc. is placed at the bottom of the narrow layer to feed the powder solid 6, which is a mixture of the powder 3 in the solid fuel and the recovered unburnt material 5 collected by the cyclone, into the narrow layer. A powder supply port 26 is disposed above the powder supply port to prevent the lumps 2 in the solid fuel received inside from flying over the fluidized bed. A lump supply port 27 having a built-in scatterer 9 for dispersing the solid fuel is provided, and the solid fuel supply port receives the solid fuel 1 and contains the lumps 2 having a particle size of about 3 to 30 mm. They are brought into contact with a classifier 18 that classifies the powder 3 and the solid unburnt material 5 having a particle size of 3 mlπ or less, but the powder 3 and the solid unburned material 5 are temporarily stored in the powder supply port 26. A hopper 16 and a powder supply device 15 are interposed in the connection. The solid unburnt material 5 stored in the hopper is fed from the cyclone 17. Next, a fluidized bed 1 is placed in the wind box.
A partition 11 is disposed on the extension line of the partition wall j3 in the wind box 4 to divide the inside of the wind box, and an adjustment damper 1 is installed in the partition.
2 to freely adjust the amount of combustion air 7 blown into the narrow layer 2o of the fluidized bed, and an ash extraction pipe 23 is provided to project outward from the bottom of the fluidized bed so that the ash is stored in the fluidized bed. This allows the ash to be extracted. Note that an air nozzle may be provided at the dispersion plate 210 IN.

Therefore, according to the present invention, the lumps 2 of the solid fuel l separated in the classifier 18 are supplied from above the fluidized bed 14 by the spreader 9, but the large particle size lumps therein are The wide layer 1 of the fluidized bed
The lumps are supplied to the fluidized bed 9 to perform fluidized combustion, but since the combustion air 7 is sufficiently sent through the wide bed, its superficial velocity is much higher than the superficial velocity in the narrow bed 20 of the fluidized bed. The large particle size lumps 2 with large particle diameters are sufficiently fluidized, and one of the separated powdery materials 3 becomes powdery solids 6 together with the recovered unburned materials 5 collected by the cyclone 17. It is fed into a narrow bed 20 of the fluidized bed 14, and the superficial velocity of the narrow bed is kept low so as not to scatter the powdery solids having small particle sizes, and the sparge is fed into the narrow bed 20. Since it is installed on the side, the aggregates 2 with small particle sizes that are dropped toward the front by the spreader are supplied into the narrow layer, where they are fluidized and burned together with the powdery solids. The amount of combustion air 7 blown to the layer can be suitably adjusted by a regulating damper 12, thereby facilitating fluidization.

As described above, this invention separates and supplies solid fuel into lumps and powders according to the particle size, so each can be fluidized at a superficial velocity depending on the particle size, and large lumps and powders can be fluidized. The combustion efficiency is extremely high because it can sufficiently fluidize even materials, and the amount of small powdery materials that are scattered is only 1 gram.Although the recovered unburned materials are powdery, they do not scatter within the narrow bed of the fluidized bed. Since the carbon is burned in a reburning furnace,
In addition to eliminating the need for a burn-up cell (CBC), the combustion efficiency can be greatly improved to about 99 mm due to recycle combustion, and the adjustment damper allows the air column in each of the narrow and wide layers of the fluidized bed to be improved. It is possible to obtain a suitable adjustment of the speed, and the dispersion device is arranged above the narrow bed in which the powder is burnt, so that the small-sized agglomerates that fall into the bed are absorbed together with the powder. Even if the amount of combustion is reduced, it is sufficient to supply fuel only to a narrow layer (in other words, it is sufficient to reduce the rotational speed of the sprayer and allow it to fall into the narrow layer in front, which reduces the furnace load. It can be said that this invention has many practical benefits, such as being able to operate in a wide range.

[Brief explanation of the drawing]

FIG. 11 is a longitudinal cross-sectional side view of a conventional fluidized bed combustion apparatus,
The figure is a circuit diagram showing an embodiment of the present invention, and FIG. 3 is a longitudinal side view of the combustion furnace. 1. Solid fuel, 2. Lump, 3. Powder, 5.
Solid unburned matter, 6. Powdered solid matter, 7. Combustion air, 8.
- Combustion furnace, 9... Spreader, IO... Wind box, 1]... Partition, 12... Adjustment chamber, 13... Partition wall, 14... Fluidized bed, 19... Wide layer, 20... Narrow layer, 21. Dispersion plate, 24. Loss gas outlet, 25. Air flow port, 26.
- Powder supply port, 27...Clumped material supply port.

Claims (1)

[Claims] Among solid fuel lumps and powder that have been separated in advance,
At the same time, the agglomerates are fed from above the narrow bed of a fluidized bed vertically divided into a wide layer and a narrow bed by a partition, and at the same time, the powder is fed into the narrow bed along with the unburned solids collected from the exhaust gas. A fluidized bed combustion apparatus characterized in that an adjusting damper is disposed in a wind box for supplying combustion air to the narrow layer and feeding combustion air into both the narrow layers so as to freely adjust the amount of air blown to the narrow layer.