JPH0515954B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a fluidized bed combustion apparatus, particularly to equipment such as a heating furnace or a combustion furnace that utilizes a fluidized bed configuration.

Conventional technology In a fluidized bed combustion apparatus, a certain amount of particles of a certain size (called fluidized material) are charged into a fluidized bed combustion furnace (vertical column) and stored, and gas is vented from below to adjust the flow rate. Continue to increase. Then, from a fixed bed where the amount of gas blowing through between particles is small and the particles are deposited at the bottom, as the amount of ventilation increases, the blow-through flow rate between particles increases, particles are blown up, and the space between particles is increased. becomes larger and begins to fall again. When the aeration rate is further increased, the vertical movement of the particles becomes more intense, and the particles flow down around a large number of air bubbles to fill the traces of the air bubbles, forming a fluidized bed.

In this fluidized bed configuration, by heating the fluidized material in advance to raise its temperature, the ignition and combustion of the main fuel, which is separately introduced, is maintained, and this is used for uniform heating of the reaction tube inserted in the fluidized bed or for smelting. .

FIG. 2 shows an example of a conventional fluidized bed combustion apparatus.

In FIG. 2, an amount of air corresponding to the flow velocity (this is called superficial velocity) required to form a fluidized bed is blown into the plenum chamber 12 at the bottom of the fluidized bed combustion furnace 11 by a blower 13. . This air fluidizes the fluidized material previously placed on the grid plate 14. On the other hand, the fuel for heating the fluid material sent from the liquid or gas fuel supply equipment 15 and the combustion air sent from the blower 13 are charged into the heating burner 16a and ignited, and the combustion heat is used to heat the fluid material. Preheating will start.

Problems to be Solved by the Invention The method described above, however, has the following problems.

First, burner ignition and combustion maintenance in a fluidized bed are
This can cause burner blockage or shift of the ignition point, which is quite difficult. Therefore, it is usually desirable to position the burner at the top of the fluidized bed, and as the height of the fluidized bed (referred to as fluidized bed bed height) increases, the position of the heating burner increases
It is necessary to move from a to 16b. Therefore, it is necessary to individually determine the optimum preheating burner position depending on the height of the fluidized bed bed, and it is also necessary to install several preheating burners in advance.

It is also possible to start preheating with the preheating burner at the optimal position by keeping the height of the fluidized bed quite high in the combustion furnace 11 from the beginning, but since the fluidized material is at a low temperature at the time of starting preheating, the air is empty. Because the column velocity is low (superficial velocity is proportional to the absolute temperature in the furnace), fluidization is poor, and when the amount of air is increased to obtain the required superficial velocity, gas is discharged from the top of the combustion furnace. The sensible heat of the exhaust gas increases, and the preheating time becomes considerably longer in both cases.

Furthermore, if the preheating burner becomes unable to burn during preheating, or if the DSS (Daily Start Stop)
If the temperature of the fluidized material falls below the ignition temperature of the main fuel during a daily shutdown (midnight shutdown), for safety reasons, the fluidized material should be cooled first, then extracted from the furnace, the height of the fluidized bed lowered, and then restarted. It is necessary to start preheating the fluid material using a preheating burner, which takes time and effort to operate.
Preheating takes too much time.

Means for Solving the Problems The present invention involves inserting a high-temperature combustion exhaust gas generator equipped with a combustion burner directly into the fluidized bed in order to heat the fluidized material to a temperature higher than the ignition temperature of the main fuel. ,
By jetting out high-temperature gas, fluidization and heating temperature can be achieved regardless of the height of the fluidized bed.

Embodiment A preferred embodiment of the present invention will be described in detail below with reference to FIG.

In FIG. 1, a high-temperature gas generating furnace 22 is inserted in the lower part of a fluidized bed combustion furnace 21. This high-temperature gas generating furnace 22 is equipped with a plurality of high-temperature gas blow-off holes 23 in its upper part. In addition, combustion burner 2
4 is inserted inside the high temperature gas generating furnace 22. This combustion burner 24 is connected to a liquid or gaseous fuel supply facility 25 and a blower 26 . Note that the wall of the high-temperature gas generating furnace 22 is made of a heat-resistant structure such as a refractory lining or water cooling.

Next, to explain its operation, fuel from the fuel supply equipment 25 and combustion air from the blower 26 are sent to the combustion burner 24 and burned in the high temperature gas generating furnace 22. The high-temperature gas generated by this combustion is ejected into the fluidized bed 21 through the plurality of ejection holes 23, and then ascends inside the furnace 21 to fluidize the fluidized material and heat the gas to raise its temperature, and after blowing through the fluidized bed. It is discharged from the upper part of the furnace 21.

Effects of the Invention Since the present invention has the configuration described above, it has the following effects.

(1) The fluidized material can be fluidized and heated regardless of the height of the fluidized bed.

(2) The optimal superficial velocity can be obtained by controlling the combustion exhaust gas amount and temperature.

(3) When reheating, there is no need to cool and extract the fluid, which not only reduces heat loss but also improves DS
S is easy.

(4) High-temperature gas may be constantly generated in a high-temperature gas generator and used to continuously heat the fluidized material, or the fuel supply from the fuel supply equipment may be stopped and the air sent from the blower may be used to flow. Blow all over the floor,
It can also be used just for fluidization.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an example of a fluidized bed combustion apparatus according to the present invention, and FIG. 2 is a system diagram showing a conventional example. 21...Fluidized bed combustion furnace, 22...High temperature gas generating furnace, 23...Gas nozzle hole, 24...Combustion burner,
25...Fuel supply equipment, 26...Blower.

Claims (1)

[Claims] 1. A high-temperature gas generator equipped with a high-temperature gas nozzle at the top was installed in the lower part of the fluidized bed combustion furnace, and a combustion burner connected to a fuel supply equipment and a blower was installed in this high-temperature gas generator. A fluidized bed combustion apparatus characterized by: