JPH06103155B2 - Operating method of atmosphere circulation type fluidized bed furnace - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for operating an atmospheric circulation type fluidized bed furnace.

(Prior Art) Conventionally, as an atmosphere circulation type fluidized bed furnace, for example,
The one shown in the figure is known.

In the figure, 1 is a furnace body, and inside the furnace body 1,
The retort 2 filled with fluidized particles such as alumina is arranged at a predetermined distance from the inner wall of the furnace, and is heated by the heating means 3 such as a heater.

Reference numeral 5 denotes a furnace lid, which is installed on the upper end surface of the furnace body 1 via a sand seal 4 and can be moved up and down by an elevating means (not shown). A material holding member 6 in the shape of a bowl is vertically provided on the furnace lid 5, and a filter 7 is provided on the lower surface of the furnace lid 5.

Reference numeral 10 is a water-cooled jacket type cyclone, and its inflow pipe 11 is connected to an exhaust pipe 8 provided in the furnace lid 5 via a sand seal 9. On the other hand, the exhaust pipe 12 of the cyclone 10 is branched into an atmosphere circulation passage 13a communicating with the nozzle type gas dispersion means 15 disposed in the lower part of the retort 2 and a discharge passage 13b opening to the atmosphere, and the atmosphere circulation Road 13a
Is equipped with a gas circulation means 14 such as a blower or an eductor type jet pump. A protective atmosphere gas supply pipe 17 having a flow rate control valve 16 is connected to the atmosphere circulation path 13a downstream of the blower 14.

The material W placed on the material holding member 6 is
Circulating atmosphere gas by the blower 14 and the gas supply pipe 17
The heat treatment is performed in the fluidized bed 18 formed by the mixed atmosphere gas including the protective atmosphere gas from.

On the other hand, in the atmospheric gas discharged from the retort 2, the fluid particles in the atmospheric gas are removed by the filter 7 and the cyclone 10, part of the atmospheric gas is discharged to the atmosphere through the discharge passage 13b, and the rest is discharged by the atmosphere circulation passage 13a. Used as a circulation.

(Problems to be Solved by the Invention) In a fluidized bed furnace, it is necessary to bring the material W into a fluid state at the time of charging into the fluidized bed 18 and at the time of extraction from the fluidized bed 18.

Therefore, in the above-mentioned atmosphere circulation type fluidized bed furnace, when the material W is charged into the fluidized bed 18 or extracted from the fluidized bed 18, the gas circulation means 14 such as a blower is provided with the furnace lid open. I will drive. Therefore, the air is in the fluidized bed
When it is supplied into the fluidized bed 18, the O ₂ concentration in the fluidized bed 18 increases, that is, there is a problem that the atmosphere in the fluidized bed 18 is greatly polluted. Further, in the fluidized bed furnace, since the temperature rising rate of the material is very high (for example, about 800 ° C / min), the material W is heated to 600 ° C or higher before the atmosphere in the retort 2 becomes non-oxidized. There was a problem that the material W was oxidized.

An object of the present invention is to provide a method for operating an atmospheric circulation type fluidized bed furnace which can surely prevent atmospheric pollution in the fluidized bed and can perform a treatment without material oxidation.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention relates to an atmosphere circulation type fluidized bed furnace in which a gas atmosphere for circulation is circulated and used in a gas circulation means of an atmosphere circulation path. A sluice valve is provided on the upstream side, the furnace lid opening period from the start of opening the furnace lid to the end of closing, the sluice valve is closed, and the operation of the gas circulation means is stopped, and the furnace lid opening period is At least at the time of charging the material into the furnace and extracting the material from the furnace, the fluidized particles in the retort are made to flow only by the protective atmosphere gas.

(Embodiment) Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

As is clear from a comparison with FIG. 3, FIG. 1 is structurally different only in that a sluice valve 18 described below is provided in the middle of the atmosphere circulation path 13a, and the others are the same. , The same parts are designated by the same reference numerals and the description thereof will be omitted.

In the present invention, during the heat treatment of the material W, the second
As shown in the figure, the sluice valve 18 is opened, the blower 14 is driven to circulate the atmospheric gas in the retort 2, and
A predetermined amount of new protective atmosphere gas is supplied from the flow rate control valve 16 into the atmosphere circulation path 13a.

Then, when the material W is extracted after a predetermined time has passed,
First, while closing the sluice valve 18 and stopping the drive of the blower 14, the flow rate control valve 16 is fully opened, and the furnace lid 5 is lifted and opened while flowing the fluidized particles only with the protective atmosphere gas.

After that, when the material holding member 6 is separated from the furnace body 1 and the material W is extracted from the fluidized bed 18, the flow rate control valve 16 is closed and the supply of the protective atmosphere gas is stopped. This state is
The next material W is placed on the material holding member 6 to form the fluidized bed 18
Continue until charged.

When the material W begins to be charged into the fluidized bed 18, the flow rate control valve 16 is fully opened to cause the fluidized particles to flow only by the protective atmosphere gas.

Then, when the furnace lid 5 is placed on the furnace body 1 (the exhaust pipe 8 and the inflow pipe 11 are connected), the sluice valve 18 is opened and the blower 14 is driven, and It is going to be in operation.

The opening of the flow rate control valve 16 of the protective atmosphere gas supply pipe 17 during this period is as shown in FIG. 2, and a large amount of protective atmosphere gas is supplied for a short time when the sluice valve 18 is switched from closed to open. Is for completely purging the inside of the retort 2.

As described above, the material holding member 6 is in the raised state, that is,
When the material W is outside the fluidized bed 18, the supply of the protective atmosphere gas is stopped so that it is not necessary to maintain the fluidized state in this period, and in this state, the air into the fluidized tank 2 is stopped. This is because there is little invasion of the gas and the atmosphere in the fluidized bed 18 is hardly contaminated, and the consumption of the protective atmosphere gas is reduced.

Although the material holding member 6 is provided integrally with the furnace lid 5 in the above embodiment, it goes without saying that the material holding member 6 is not limited to this. Further, although the gas dispersion means 15 is of the nozzle type, it may be of the dispersion plate 15a type as shown in FIG.

(Effects of the Invention) As is apparent from the above description, according to the present invention, when the furnace lid is in the open state, the sluice valve is closed and the gas circulation means is stopped, so that air enters the fluidized bed. Without doing so, the material is prevented from being oxidized and the amount of the protective atmosphere gas for purging used at the start of the operation is reduced.

Moreover, when the material holding member is outside the fluidized bed, by stopping the supply of the protective atmosphere gas, the amount of the protective atmosphere gas used can be greatly reduced and the running cost can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of an atmospheric circulation type fluidized bed furnace to which the present invention is applied, and FIG. 2 is a cycle motion diagram in one cycle of a blower, a sluice valve, and a new atmospheric gas in FIG. FIG. 3 is a sectional view showing another embodiment of the gas dispersion means, and FIG. 4 is a schematic view of a conventional atmosphere circulation type fluidized bed furnace. 1 ... furnace body, 2 ... retort, 3 ... heating means, 5 ...
… Furnace lid, 6 …… Material holding member, 8 …… Exhaust pipe, 9 …… Sand seal, 11 …… Inflow pipe, 13a …… Open passage, 14 …… Gas circulation means, 15 …… Gas dispersion means, 16 ...... Flow control valve,
18 ... Gate valve.

Claims (1)

[Claims] 1. An atmosphere circulation type fluidized bed furnace in which an atmosphere gas for fluidization is circulated and used by a gas circulation means, and a sluice valve is provided on the upstream side of the gas circulation means in an atmosphere circulation path, and the opening and closing of the furnace lid is completed. To the furnace lid open period, the gate valve is closed, and the operation of the gas circulation means is stopped, and at least the material is charged into the furnace and the extraction operation from the furnace is performed during the furnace lid open period. At this time, a method for operating an atmosphere circulation type fluidized bed furnace characterized in that the fluidized particles in the retort are made to flow only by a protective atmosphere gas.