JPH0223932Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an apparatus for uniformly supplying fuel to a fluidized bed combustion apparatus such as a fluidized bed boiler or a fluidized bed incinerator.

Prior Art Solid fuel supply methods generally applied to fluidized bed combustion equipment include (1) a method in which fuel is fed under pressure by conveying air through a fuel supply pipe that communicates from the bottom of the fluidized bed into the fluidized bed; A method in which a fuel dispersion device (spreader) is installed on the side wall surface above the bed and the fuel is spread onto the fluidized bed. (3) A screw type feeder is installed above the fluidized bed or on the side of the bed and the fuel is forced into the fluidized bed. There is a method.

Problems to be solved by the invention However, although the method (1) above has the advantage of being able to uniformly supply fuel into the fluidized bed by increasing the number of fuel supply pipes, on the other hand, the lower part of the fluidized bed is A pressure equal to the weight of the medium is applied, and when fuel is supplied from below, it is necessary to overcome this pressure and pressurize it in. Therefore, the pressure of the conveying air must be greater than this pressure, which reduces power consumption. The disadvantage is that it becomes large. In addition, pipes that transport fuel are limited by the solid/gas transport limit, which limits the amount of moisture attached to the transported material, particle size, etc., and there is also a minimum limit on the flow velocity within the pipe, so there is a problem of wear on the transport pipe, and it is necessary to reduce the amount of water. There are problems with installing fuel drying equipment and its power consumption, which is uneconomical. Furthermore, when performing low-load operation, a fluidized bed boiler may perform so-called slumping, in which fuel supply and fluidization of cells into which the fluidized bed is divided are stopped. In this case, in the stop cell, the flowing medium flows back into the fuel supply pipe and must be blown out at the next startup, making the operation complicated, and in the worst case, the fuel supply pipe may become clogged. .

In addition, in the method (2) above, the dispersion onto the fluidized bed takes a mountain-shaped shape with the center as the apex.
Non-uniform distribution of fuel to the peripheral edges results in non-uniform bed temperatures. Furthermore, since the fuel is sprayed from the sides onto the freeboard on the layer by the spretzer, the fine powder and the fuel pulverized by the spretzer are burned on the freeboard on the layer, increasing the temperature of the freeboard and increasing the temperature inside the layer. goes down. This causes problems when controlling SOx and NOx. In addition, when performing slumping, it is difficult to spray fuel only on the operating cells with a spreader, and there is a risk that the fuel will be sprayed on the stopped cells, causing a state of evaporation and clinker generation, which will cause problems when starting up next time. There are drawbacks.

Furthermore, in the method (3) above, when fuel is supplied, it is difficult to equalize the fuel distribution because it is introduced from the side. The problem is that it becomes complicated and costs high.

The present invention was devised in view of the above points, and an object of the present invention is to provide a fuel supply device for a fluidized bed combustion apparatus that can uniformly supply fuel.

Means for Solving the Problems The fuel supply system of the fluidized bed combustion apparatus of the present invention will be described using the numbers shown in FIGS. 1 to 4. In a fluidized bed combustion apparatus in which a fluidized bed 3 is formed above the air dispersion plate 2 through an air distribution plate 2, and a freeboard 5 is formed above the fluidized bed 3, a scraper type combustion apparatus is formed above the freeboard 5 through a chute 6. This fuel supply machine 7 is arranged to have almost the same length as the width of the fluidized bed 3, and further widens from the upstream side to the downstream side to equalize the amount of fuel supplied. It is characterized in that it is provided with an adjustment gate 10 having a substantially triangular opening 8 for.

Operation The fuel falling from the fuel hopper 15 via the rotary valve 17 is introduced into the drop port 18 of the scraper type fuel supply device 7. The fuel supply machine 7 has a plurality of scrapers 11 attached to a chain,
It is driven by an electric motor 12 in the direction of the arrow.
Below the scraper 11, there is an adjustment gate 10 which is opened in a triangular shape and becomes wider as it goes from the supply side to the other end. While being transported to the water, the liquid falls uniformly from the adjustment gate 10 through the chute 6 onto the fluidized bed 3.

Embodiment An embodiment of the present invention will be described in the case of a fluidized bed combustion boiler. The present inventors conducted an experiment on the diffusion situation in the tube axis direction and in the direction perpendicular to the tube axis when fuel was supplied to a fluidized bed having heat transfer tubes in one direction within the layer. The results were as shown in FIG. From FIG. 5, it can be seen that diffusion in the direction perpendicular to the tube axis within the layer requires several times as much diffusion as in the tube axis direction. This is because in the direction perpendicular to the tube axis in the layer, the tube becomes a wall and acts as a resistance to the diffusion of the fuel, but in the tube axis direction, the fuel moves parallel to the tube, so there is almost no resistance. That is, it can be seen that in order to uniformly supply the fuel within the bed, if the fuel is supplied evenly in a direction perpendicular to the tube axis, the fuel will be evenly distributed throughout the bed. This embodiment utilizes this characteristic.

As shown in FIGS. 1 to 4, there is a wind box 1 at the bottom into which air sent from a blower flows, and a fluidized bed 3 is formed above the wind box 1 via an air distribution plate 2. A heat exchanger tube 4 is provided horizontally within the fluidized bed 3, and a freeboard 5 is formed above the fluidized bed 3 to constitute a fluidized bed boiler.

A relatively long chute 6 above the freeboard 5
Connect the scraper type fuel supply machine 7 via
This fuel supply device 7 is disposed in a direction perpendicular to the tube axis of the heat transfer tube 4 and has a length that is approximately the same as the width of the fluidized bed 3, and further increases in fuel supply amount from the upstream side to the downstream side. An adjustment gate 10 having a substantially triangular opening 8 is provided to equalize the area. The fuel supply machine 7 includes a plurality of scrapers 1 in a chain.
1 is attached, and is driven by an electric motor 12 in the direction of the arrow. scraper 11
As shown in FIG. 3, an adjustment gate 10 having a triangular opening that becomes wider from the supply side to the other end is provided on the lower side of the opening. Reference numeral 13 denotes a slide adjustment plate for adjusting the area of the triangular opening 8 in the adjustment gate. 14 is a fuel inlet, 15 is a fuel hopper, 16 is a gate valve, 1
7 is a rotary valve, 18 is a drop port, 20 is a partition plate, 21 is a flue, and 22 is an air inlet.

In the apparatus of the present invention configured as described above, the fuel dropped from the rotary valve 17 is input into the drop port 18 of the fuel supply device 7. While this fuel is being conveyed to the other end by the scraper 11, it is uniformly thrown onto the fluidized bed 3 through the triangular opening 8 of the regulating gate 10, through the chute 6.

Effects of the invention Since the invention is configured as described above, it has the following effects.

(1) Fuel can be uniformly injected onto the fluidized bed with a simple configuration.

(2) The fuel supply machine is easy to handle, and the moving parts are slow, so there is less wear and tear on the equipment.

(3) Since the fuel is not crushed and falls by gravity, there is less fuel in the freeboard and most of it burns within the layer, making it easy to control pollution values such as NOx and SOx.

(4) Since the fuel feeder is not exposed to radiant heat or high temperatures from inside the furnace, it does not require high-grade materials and can be manufactured at low cost.

[Brief explanation of drawings]

Fig. 1 is an explanatory cross-sectional view showing one embodiment of the fuel supply system for a fluidized bed combustion apparatus of the present invention, Fig. 2 is an explanatory cross-sectional view taken along the line - in Fig. 1, and Fig. 3 is an enlarged - line in Fig. 1. Fig. 4 is an explanatory cross-sectional view taken along the - line in Fig. 1, and Fig. 5 shows the experimental results conducted by the present inventors. It is a graph showing the diffusion situation in the tube axis direction and in the direction perpendicular to the tube axis when supplied. 1... Wind box, 2... Air dispersion plate, 3... Fluidized bed, 4... Heat exchanger tube, 5... Free board, 6...
Chute, 7...Fuel supply machine, 8...Triangular opening, 10...Adjustment gate, 11...Scraper,
12...Electric motor, 13...Slide adjustment plate, 14
...Fuel inlet, 15...Fuel hopper, 16...
Gate valve, 17...Rotary valve, 18...
...Drop opening, 20... Partition plate, 21... Flue, 22
...Air inlet.

Claims (1)

[Scope of utility model registration request] In a fluidized bed combustion equipment that has a wind box at the bottom, a fluidized bed is formed above the wind box via an air distribution plate, and a freeboard is formed above the fluidized bed, a chute is placed above the freeboard. A scraper-type fuel supply machine is connected through the fluidized bed, and this fuel supply machine is arranged with a length that is almost the same as the width of the fluidized bed, and further widens from the upstream side to the downstream side to evenly distribute the fuel supply amount. 1. A fuel supply device for a fluidized bed combustion apparatus, comprising an adjustment gate having a substantially triangular opening for controlling the fuel supply.