JPS59109705A - Fuildized-bed combustion device - Google Patents

Abstract

PURPOSE:To prevent the pressure loss developed by blowing-in high temperature gas at the start or the like from occurring and miniaturize facilities such as pressure fan and the like by a method wherein the openin area of a dispersing plate to form fluidized bed is made variable. CONSTITUTION:A dispersing plate 2 consists in being installed with a number of tubular bodies 7, on each of which first gas flowing holes 8 are bored and on the upper end retaining part 10 of each of which a buffer 11 is placed so as to seal said upper end and at the outside of said part 10 of each of which a cap 12 with second gas flowing holes 13 is put. During the time when gas pressure is low, such as steady state or the like, fluidizing gas 15 fed from a wind box 3 is raised through the opening part of the dispersing plate 2 and blown up through the first gas flowing holes 8 to a fluidized bed in order to fluidize fluidizing medium. However, when high temperature gas is blown in such is the case at the start or the like, because of higher gas pressure, the floating- up of the buffers 11 placed on the upper end retaining part 10 of the tubular bodies 7 are caused in addition to the flowing-out of gas through the first gas flowing holes 8 and the flowing-out of gas from the clearances, which are made between the retaining parts 10 and the buffers 11 by their floating-up, through the second gas flowing holes 13 of the caps 12 is resulted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluidized bed combustion apparatus, and more particularly to a fluidized bed combustion apparatus in which a dispersion plate is improved to prevent pressure loss during startup.

A fluidized l-combustion device is one in which a furnace is filled with a fluidized medium, and a fluidizing gas is blown into the furnace from a lower gas distribution plate to fluidize the fluidized medium while burning fuel. A fluidized bed boiler, which is the standard ml+1 fluidized bed combustion device, has heat transfer tubes placed in a flow I sublayer, but compared to conventional boilers, the heat transfer coefficient of the heat transfer tube portion in the fluidized bed is higher, and it is still There are advantages to direct desulfurization by having a desulfurizing agent such as limestone in the fluidized bed.

FIG. 1 shows a conceptual diagram of a conventional boiler device, in which a distribution plate (perforated plate) 2 is provided at the bottom of a furnace 1.
A wind box 3 is provided at the bottom of the wind box 3, and a fluidized bed 4 of a fluidized medium (such as sand) is formed on the dispersion plate 2 by the fluidizing gas introduced therefrom.

Note that 6 is a fuel (coal) supply pipe, 2o is a fluidizing gas supply u121 is a supply section thereof, and the supply section in this case has a structure including a starting burner.

In the apparatus configured as described above, during steady operation, gas preheated by an air heater (for example, 250°C) is supplied from the fluidizing gas supply pipe 2o, and is blown into the fluidizing medium through the dispersion plate 2 to fluidize the fluidizing medium. However, since the fluidized medium is cooled when starting the boiler, the starting burner 21 installed at the 200 Å port of the fluidizing gas supply pipe
is operated to heat the gas to, for example, 900°C.

However, when using this startup method, the capacity of the fluidizing gas increases due to the high temperature, and the pressure when passing through the distribution plate 2 becomes excessive, so the capacity of the forced fan must be increased. There are drawbacks. For example, the differential pressure across the dispersion plate 2 during steady operation is 200 HzO, but in the case of gas at 900°C at startup, this differential pressure rises to 1000 mxI (20 Hz), and the output of the forced fan increases by that amount. It was not economical to prepare a large-capacity blower only for startup.

The purpose of the present invention is to solve the above-mentioned drawbacks of the prior art, and to provide fluidized bed combustion that does not cause a large pressure loss even when high-temperature fluidizing gas is supplied, and does not require a large-capacity forced fan even at startup. The goal is to provide equipment.

The present invention blows high-temperature gas through a dispersion plate at startup,
A fluidized bed combustion apparatus that forms a fluidized bed is characterized in that the opening area of a dispersion plate through which gas passes is made variable between startup and regular injection.

In the present invention, in order to make the aperture area of the dispersion plate variable, the dispersion plate can be constructed by stacking a plurality of sliding LiT-capable plates, and the aperture area can be made variable by sliding. An oily body having a first gas flow hole is placed upright at the opening of the distribution plate, and the oily body is placed through the receiving part so as to seal the upper end of the cylindrical body, and a second oily body is placed on the outside thereof. A cap is provided with a gas flow hole, and when the gas pressure is low during steady state, the first gas flow hole is used, and when the gas pressure is high during startup, the gas flow hole is opened from the first gas flow hole. is pushed up by gas pressure, and the gas is caused to flow out from the second gas flow hole provided in the cap of the cylindrical body.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 2 shows an embodiment of the dispersion plate used in the fluidized J-combustion device of the present invention. This dispersion plate 2 consists of two upper plates and a lower plate 2B, each having openings 20A and 20B of the same area, which are slidably stacked together in parallel. Either one of the upper plate 2A and the lower plate 2B may be made slidable, or both may be made slidable. Further, the openings 2A and 2B can have different opening areas, such as elongated holes and round holes, or can be made into irregular shapes. The structure for sliding the distribution plate may be, for example, one employed in a normal slide damper. By sliding the upper plate 2A and the lower plate 2B in the direction of the arrow, the opening area of the dispersion plate 2 can be changed arbitrarily. In this way, when the gas temperature at startup is high, the opening area is made large, while when the gas temperature is low and steady, the opening area is made small, so that the pressure loss can be adjusted within a predetermined range.

3 and 4 are enlarged sectional views showing embodiments of the dispersion plate of the fluidized bed combustion apparatus of the present invention.

This dispersion plate 2 includes a cylindrical body 7 having first gas flow holes 8.
is erected at the opening of the dispersion plate 2, and the buffer body 11 is placed on the receiving part 10 at the upper end of the cylindrical body 7 so as to seal the upper end.
Further, a cap 12 having a second gas flow hole 13 is placed on the outside thereof. As the loose body 11, a metal ball, a ceramic ball, etc. having a heat resistance of 15 mm or more is preferably used. Ceramic balls are particularly preferred because of their wear resistance. The diameter of the first gas flow hole 8 of the cylindrical body 7, the weight of the guard body 11, and the diameter of the second gas flow hole provided in the cap 12 are changed in order according to the gas pressure.
and the second flow hole is appropriately determined to be open.

That is, when the gas pressure at steady state is low, the gas pressure body 11 does not float up, and the upper end receiving portion 10 of the small diameter portion 9 of the convex body 7 is maintained in a sealed state to open the first gas flow hole 8. On the other hand, when high-temperature gas is blown in during startup, the buffer body 11 is pushed up by the gas pressure, and gas flows out from the second gas flow hole 13 of the cap 12 in addition to the first flow hole 8. Allow gas to flow.

In the above configuration, when the gas pressure is low such as during steady state,
The fluidizing gas 15 from the wind box 3 rises through the opening of the dispersion plate 2 and is blown up into the fluidized bed section through the first gas flow hole 8 of the cylindrical body 7, thereby fluidizing the fluidized medium. Further, when high-temperature gas is blown during startup, etc., the gas pressure becomes high, so that the gas is placed on the upper end receiving part 10 of the cylindrical body 7 in the pond where the gas flows out from the first communication hole 8. The gas pressure body 11 floats up due to the gas pressure, and gas flows out from the gap through the second gas flow hole 13 of the cap 12.

In this way, it is possible to suppress the increase in gas pressure when using high-temperature gas at the time of startup, and prevent pressure loss.

In the embodiments described above, the gas flow holes provided in the cylindrical body and the cap may be not only round holes but also slit holes, and the gas communication holes may be provided in the small diameter portion 9 in the case of the cylindrical body, for example.

As described above, according to the present invention, by making the opening area of the dispersion plate that forms a fluidized bed variable, pressure loss can be prevented when high temperature gas is blown during startup, etc. can be made smaller than before.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of a conventional fluidized bed combustion apparatus, FIG. 2 is a sectional view showing an embodiment of a dispersion plate used in the fluidized bed combustion apparatus of the present invention, and FIGS. 3 and 4. FIG. 3 is a partial cross-sectional view showing another embodiment of the dispersion plate used in the fluidized bed combustion apparatus of the present invention. 1... Furnace, 2... Dispersion plate, 2 people... Upper plate, 2
B...lower plate, 20A, 20B...opening, 3...
- Wind box, 4... Fluidized bed, 7... Cylindrical body, 8... First gas distribution hole, 9... Small diameter part, lO... Upper end receiving part,
11...Buffer, 12...Cap, 13...I
g2 gas flow hole. Agent Patent Attorney Takenaga Kawakita

Claims (1)

[Claims] (1) In a fluidized bed combustion device that blows high-temperature gas through a dispersion plate to form a fluidized bed at startup, the opening area of the dispersion plate through which gas passes is made variable between startup and steady state. A fluidized bed combustion apparatus characterized by: (2. A fluidized bed combustion device according to claim 1, in which the dispersion plate is constructed by stacking a plurality of slidable plates, and the opening area of the dispersion plate is made variable by sliding. (3) In claim 1, a cylindrical body having a first gas flow hole is erected at the opening of the dispersion plate, and a receiving portion is provided at the upper end of the cylindrical body so as to seal the upper end. A buffer body is placed through the cap, and a cap having a second gas flow hole is provided on the outside of the cap. In this case, a buffer body is pushed up by gas pressure to the west of the first gas distribution hole, and the gas flows out from the second gas distribution hole 9 of the cap of the shaft. Combustion device.