JP2002062056A - Method for sintering particle aggregate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for sintering particle aggregate capable of attaining sintered particle aggregate of high strength while restricting an increase in consumption of heat energy and further capable of improving gaseous state discharged from inside a fluidized bed furnace. SOLUTION: A sintering segment 6 with its upper part being connected to a gaseous combustion segment 8 of a fluidized bed furnace through a communicating pipe 7 is installed near the fluidized bed furnace. Particle aggregate is fed into the sintering segment to heat it up to a high temperature with a burner 9 and the material is sintered. Combustion gas of the burner 9 is supplied to a gaseous combustion segment 8 through the communicating pipe 7 and gas agitation in the furnace is promoted, so that CO contained in the discharged gas of the fluidized bed furnace can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for sintering granular aggregate using a fluidized-bed furnace.

[0002]

2. Description of the Related Art In recent years, fluidized-bed furnaces have been widely used for incineration of municipal garbage and sewage sludge, but a large amount of incineration ash is generated by incineration, and the treatment method has become a problem. Therefore, in order to make effective use of the incinerated ash, a method of producing granular aggregates with strength and chemical stability by granulating and sintering the incinerated ash collected by a dust collector provided at the latter stage of the fluidized furnace. Is being developed. Generally, sintering of the granular aggregate requires a temperature higher than the temperature inside the fluidized-bed furnace.

For this reason, a high-temperature aggregate sintering furnace is usually provided independently of a fluidized-bed furnace to sinter granular aggregates. However, in order to maintain the inside of the aggregate sintering furnace at a high temperature. Requires a large amount of heat energy, resulting in a high running cost.

[0004] Further, as disclosed in Japanese Patent No. 2909421 of the present applicant, a method has been developed in which granulated aggregate is charged into a circulating fluidized-bed furnace and sintered. However, as described above, since the sintering of the granular aggregate requires a temperature higher than the furnace temperature of the fluidized-bed furnace, the temperature of the entire furnace is set to be slightly higher in order to obtain a granular aggregate having high strength. Alternatively, it is necessary to set the temperature at least in the vicinity of the bottom of the furnace slightly higher. Therefore, it is inevitable that the consumption of heat energy is considerably increased as compared with a general fluidized-bed furnace. In addition, since the granular aggregate is taken out in a state of being mixed with the fluid medium, there is also a problem that it takes time and effort to separate the granular aggregate.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and sinters the granular aggregate while minimizing the increase in the consumption of heat energy to thereby increase the strength of the granular aggregate. The present invention has been made to provide a method of sintering granular aggregate which does not require separation of granular aggregate and a fluid medium, and also has an effect of improving gas properties discharged from the fluidized-bed furnace. It is a thing.

[0006]

In order to solve the above-mentioned problems, a method for sintering granular aggregates according to the present invention is described. A method for sintering granular aggregates is described below. A connected sintered part is provided, and granular aggregate is put into the sintered part, heated by a burner and sintered, and the combustion gas of the burner is supplied to a gas phase combustion part of a fluidized-bed furnace to flow. It is characterized by promoting gas agitation in the furnace. In addition, it is preferable that the granular aggregate is continuously charged into the communicating pipe via the double damper, and the sintered granular aggregate is continuously discharged through the double damper at the bottom of the sintered portion. .

According to the present invention, since only the granular aggregate is supplied into the small-volume sintering section and heated by the burner, it is possible to obtain a high-strength granular aggregate. No need for separation. In addition, since the combustion gas of the burner is supplied to the gas-phase combustion section of the fluidized-bed furnace, there is no loss of heat energy, and the combustion gas supplied to the gas-phase combustion section can promote gas agitation in the fluidized-bed furnace. In addition, the properties of gas discharged from the fluidized furnace can be improved.

[0008]

Embodiments of the present invention will be described below. FIG. 1 is a view showing an embodiment of the present invention. 1 is a fluidized furnace such as a fluidized incinerator, 2 is a fluidized medium such as silica sand, and the fluidized medium 2 is fluidized by flowing air blown from a dispersion pipe 3. As in the conventional furnace, the waste is burned at a temperature of, for example, about 650 ° C. while vigorously stirring the waste. The average particle size of the fluid medium 2 is, for example, 300 μm
It is about. The incinerated ash discharged from the fluidized-bed furnace 1 is collected by a dust collector 4 at a later stage, and is made into a granular aggregate having a particle size of about 5 to 15 mm by a granulator 5.

In the vicinity of the fluidized-bed furnace 1, a straight tubular sintered part 6 is formed. The sintering section 6 is connected to a side surface of a gas-phase combustion section 8 of the fluidized-bed furnace 1 by an upper communication pipe 7.
A burner 9 is provided in the sintering section 6, and the inside of the sintering section 6 is
It can be heated to a high temperature of about 1000 ° C.

The communication pipe 7 is provided with an inlet 10 for the granular aggregate granulated by the granulator 5. As shown in the figure, double dampers 11 and 12 are provided in the inlet 10, and by opening and closing them alternately, a certain amount of granular aggregate can be injected while blocking the outside air and the inside. Double dampers 13, 14 are also provided at the bottom of the sintering section 6, and by opening and closing them alternately, the sintered granular aggregate can be discharged by a fixed amount. For this reason, continuous firing can be performed by the burner 9 while always keeping the amount of the granular aggregate in the sintered portion 6 constant.

According to the present invention, the incinerated ash is collected by a dust collector 4 while incinerating sewage sludge or the like at about 650 ° C. in a fluidized furnace 1, and granulated by a granulator 5 into a granular aggregate having a particle size of about 5 to 15 mm. . The granular aggregate is charged into the sintering section 6 by a predetermined amount from the input port 10 and is heated to a high temperature of about 1000 ° C. by the burner 9 to be strongly sintered.

Since the volume of the sintering section 6 is much smaller than the volume of the fluidized-bed furnace 1, the heat energy for maintaining only the sintering section 6 at a high temperature may be relatively small. And burner 9
Is supplied to the gas-phase combustion section 8 of the fluidized-bed furnace 1 through the communication pipe 7, so that the heat energy generated by the burner 9 is not wasted. Further, by blowing the combustion gas of the burner 9 into the gas phase combustion section 8 of the fluidized-bed furnace 1, gas agitation in the fluidized-bed furnace 1 is promoted, and the CO concentration in the exhaust gas of the fluidized-bed furnace 1 is reduced as compared with the conventional fluidized-bed furnace. There is an effect that can be. This point will be shown in more detail in the data of the embodiment.

The granular aggregate thus sintered is discharged by a predetermined amount by alternately opening and closing the double dampers 13 and 14 at the bottom of the sintered part 6. At the same time, if the same amount of unsintered granular aggregate is charged into the sintering section 6 through the charging port 10, the amount of the granular aggregate in the sintered section 6 can be kept constant at all times, and stable sintering can be achieved. It is possible to make a conclusion.

When the granular aggregate is introduced into the fluidized-bed furnace 1 and sintered as in the prior art, the fluidized medium 2 and the granular aggregate are taken out in a mixed state. However, in the present invention, the sintered granular aggregate can be taken out of the sintering section 6 by itself, so that there is no need for separation.
Since this granular aggregate has excellent strength as shown in the data of the examples, and also has no fear of elution of heavy metals,
It can be used for applications such as road paving materials and building materials.

[0015]

EXAMPLES Table 1 shows examples and comparative examples in which granular aggregates were sintered according to the present invention. Embodiment 1 is an example in which the communication pipe is connected to the middle stage of the gas-phase combustion section of the fluidized-bed furnace, and Embodiment 2 is an example in which the communication pipe is connected to the upper part of the gas-phase combustion section of the fluidized-bed furnace. Comparative Example 1 is an example in which a communication pipe was connected to a sand layer of a fluidized-bed furnace. In addition, data of a fluidized-bed furnace having no sintered part is shown as a reference example. The numerical value in the column of strength indicates the force required to crush one granular aggregate.

[0016]

[Table 1]

As described above, according to the embodiment of the present invention,
A sintered granular aggregate having high strength can be obtained, and the concentration of CO contained in the exhaust gas from the furnace can be reduced. On the other hand, in the comparative example, the CO concentration in the exhaust gas from the furnace is slightly higher.

[0018]

As described in detail above, according to the method for sintering granular aggregates of the present invention, it is possible to obtain granular aggregates having high strength while minimizing an increase in heat energy consumption. be able to. The obtained granular aggregate hardly dissolves heavy metals, and can be safely used for various applications. Also,
Since the sintered granular aggregate can be taken out alone, it is not necessary to separate it from the fluid medium. Moreover, according to the present invention, the combustion gas of the burner in the sintering section is supplied to the gas phase combustion section of the fluidized-bed furnace to promote gas agitation in the fluidized-bed furnace, thereby improving the properties of gas discharged from the fluidized-bed furnace. There are many advantages such as being able to be converted.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

[Explanation of symbols]

1 fluidized furnace, 2 fluidized media, 3 dispersion tube, 4 dust collector,
Reference Signs List 5 granulator, 6 sintering section, 7 communication pipe, 8 gas phase combustion section, 9 burner, 10 inlet for granular aggregate, 11, 12
Double damper, 13, 14 Double damper

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Naoto Watanabe No. 56, Suda-cho, Mizuho-ku, Nagoya-shi, Aichi Japan F Co., Ltd. F-term (reference) 4K046 HA12 JA10 JD02 JE01 JE08 KA01

Claims (2)

[Claims] 1. A sintering section having an upper portion connected to a gas phase combustion section of a fluidized-bed furnace by a communicating pipe is provided near the fluidized-bed furnace, and granular aggregate is put into the sintered section and heated by a burner. A method for sintering granular aggregates, comprising: supplying a combustion gas from a burner to a gas phase combustion section of a fluidized-bed furnace to promote gas agitation in the fluidized-bed furnace. 2. The granular aggregate is continuously charged into the communicating pipe via the double damper, and the sintered granular aggregate is continuously discharged through the double damper at the bottom of the sintering section. Claim 1
A sintering method of the granular aggregate according to the above.