JPH08285465A - Fluidized bed furnace - Google Patents

Abstract

PURPOSE: To effectively ensure a flow path in a cylindrical furnace main body without forming a dead zone. CONSTITUTION: A spiral partition wall is provided on a gas distribution plate 12 of a cylindrical furnace body 11. Ore powder to be treated is charged into the furnace body from an inlet 14 at the center and discharged from an outlet 15 provided on the side wall of the furnace body 11. A spiral flow path 16 is formed from the inlet 14 to the outlet 15 along the partition wall. As the flow path is spiral, the long flow path 16 can be ensured by effectively using the inside space even though the furnace body 11 is cylindrical.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a method for preheating a solid on a powder,
The present invention relates to a fluidized bed furnace used for performing a physical treatment such as drying or granulation, or a chemical treatment such as a reaction, and more particularly to a fluidized bed furnace having a cylindrical furnace body.

[0002]

2. Description of the Related Art Conventionally, a cylindrical fluidized bed furnace as shown in FIG. 6 has been used for physical or chemical treatment of a granular material. Typical prior art is disclosed, for example, in US Pat. No. 5,118,479. In this prior art, hematite (Fe) contained in iron ore
₃ O ₂ ) and other iron oxides are carbonized to give cementite (Fe
_A fluidized bed reactor is used to produce iron anchor carbides such as ₃ C). In that reactor,
A cylindrical furnace body 1 is installed so that the axis is vertical, a horizontal gas dispersion plate 2 is provided, and a fluidized bed of iron ore powder is formed on the gas dispersion plate 2. The space above the gas dispersion plate 2 is the partition plate 3
Thus, the flow path 6 between the inlet 4 for charging the iron ore powder and the outlet 5 for discharging the carbonized eye anchor carbide has a bent shape, so that the substantial distance of the flow path 6 is increased. It is configured. When the flow path 6 becomes longer, the average residence time of the raw material powder in the furnace body 1 becomes longer, and a high reaction rate can be obtained even if the reaction rate of the desired reaction is low.

In the arrangement of the partition plate 3 as shown in FIG. 6, since the flow path 6 changes at a large angle, a dead zone in which the treated powder stays in a fluidized bed state or a state of being deposited on the gas dispersion plate 2. However, they are easily formed as shown by hatching. If the partition plate 3 is not provided, a uniform fluidized bed is formed in the furnace body 1 as a whole. In such a simple one-stage continuous fluidized bed furnace, assuming a perfect mixing state, the charged processing powders are uniformly mixed instantaneously and discharged with a residence time as shown in FIG. . In this example, for example, 63% of the treated powder is discharged within one hour of the average residence time. As a result, for example, an unreacted rate of 0.1 per hour
A fluidized bed furnace capable of loading 250 tonnes of raw material is required to obtain 1% tonnes of product.

As shown in FIG. 8, if the fluidized bed furnace is multi-staged and the upper stage outlet 5 and the lower stage inlet 4 are connected by a connecting pipe 8, the powder which is immediately discharged in the first stage can be obtained. The particles may also remain for a long time in the next stage. For example, in order to obtain a product of 1 ton with an unreacted rate of 0.1% in one hour, 14 tons are divided into 7 tons and the first and second stages are separated. What is necessary is just to charge each. Assuming that the time required for one particle to complete the reaction is θ0, the average residence time θ when the unreacted rate is 0.1% is θθ in one stage.
= 250θ0, θ = 14θ0 in two stages, θ = 5θ0 in three stages
Becomes That is, if the number of stages is large, the furnace body of each stage can be made small. The residence time distribution in this case is shown in FIG.
As shown by a two-dot chain line, the residence time distribution can be adjusted to a desired time, and efficient processing is possible. However, in the multi-stage fluidized bed furnace, the size of the apparatus becomes large and the manufacturing cost increases.

[0005]

In the fluidized bed furnace as shown in FIG. 6, since the partition plate 3 is provided in a straight line, the flow path 6 which is not unreasonable for the cylindrical furnace body 1 is provided. It is difficult to form, and the dead zone 7 shown by hatching is likely to be formed. In the arrangement of the partition plate 3 as shown in FIG. 6,
About 18% dead zone is formed. Dead zone 7
Then, the processing particles are deposited on the gas dispersion plate 2 to reduce the effective cross-sectional area of the flow path 6, increase the flow velocity along the flow path 6, and reduce the residence time of the processing powder in the furnace body 1. The reaction rate decreases. The processing powder deposited in the dead zone 7 is
Since the reactor stays in the furnace body 1 for a long time, the reaction proceeds excessively, and an undesired reaction is likely to occur or the quality is likely to deteriorate. Furthermore, since the accumulation of the treated powder in the dead zone 7 increases with the operation time, the optimal operation conditions change with the lapse of time, and it becomes difficult to maintain a stable operation.

An object of the present invention is to provide a fluidized-bed furnace in which the flow path can be extended without forming a dead zone even when the furnace body is cylindrical.

[0007]

SUMMARY OF THE INVENTION The present invention provides a fluidized-bed furnace in which a dispersion plate is provided on a cylindrical furnace body, and a gas is blown from below the dispersion plate to form a fluidized bed of the treated powder on the dispersion plate. , Wherein a spiral partition is provided on the dispersion plate. Further, the present invention provides a fluidized bed furnace in which a dispersion plate is provided in a cylindrical furnace body, and a gas is ejected from below the dispersion plate to form a fluidized bed of the treated powder on the dispersion plate. The fluidized bed furnace is characterized in that annular partitions are provided concentrically, and each annular partition is formed with a communicating portion for communicating the inside and outside with a radius different from that of an adjacent annular partition. Further, the cylindrical furnace body according to the present invention is characterized in that a processing powder loading port is provided at a center portion and a processing powder discharge port is provided at a side wall portion. Further, the cylindrical furnace body of the present invention is characterized in that a processing powder loading port is provided in a side wall portion and a processing powder discharge port is provided in a central portion.

[0008]

According to the present invention, a spiral partition is provided on the dispersion plate provided in the cylindrical furnace body, so that the fluidized bed of the treated powder can be moved along the spiral flow path. . Therefore, even if the furnace body is cylindrical, a sufficient treatment can be performed by effectively using the furnace body without forming a dead zone.

According to the invention, in a cylindrical furnace body,
A plurality of annular partitions are provided concentrically on the dispersion plate, and each annular partition has a different radius from the adjacent annular partition,
A communication part is formed to communicate the inside and the outside.

The fluidized bed of the treated powder formed on the dispersion plate moves in the radial direction at the communicating portion while flowing in the circumferential direction along each annular partition. Since the communicating portions are formed on different radii in the adjacent annular partitions, the fluidized bed moves along the curved flow path while repeating movement in the circumferential direction and movement in the radial direction, and within the furnace body. Sufficient processing can be performed without forming a dead zone.

Further, according to the present invention, the treated powder is charged through a charging port provided at the center of the cylindrical furnace body and discharged through a discharging port provided at the side wall. The flow path from the processing powder loading inlet to the processing powder discharge port flows smoothly without forming a dead zone in the cylindrical furnace by a spiral or concentric partition plate, and the side wall is discharged. A treated product having a high reaction rate can be easily obtained from the outlet.

Further, according to the present invention, since the charging powder inlet is provided in the side wall of the furnace body, the processing powder can be easily charged into the furnace body.

[0013]

1 shows a simplified plan view of a first embodiment of the present invention, and FIG. 2 shows a cross-sectional view taken along line II-II of FIG. The furnace body 11 having a cylindrical cross section is installed so that its axis line is vertical, and the gas dispersion plate 12 is arranged substantially horizontally. A spiral partition plate 13 is erected on the gas dispersion plate 12. The furnace body 11 has an inlet 14 for charging ore, which is a processing powder, at the center of the gas dispersion plate 12.
Is provided, and an outlet 15 for discharging the processed ore is provided on the side wall of the furnace body 11. Inlet 14 and outlet 15
A spiral channel 16 is formed along the partition plate 13 between and. The gas dispersion plate 12 is provided with a nozzle 17 for ejecting a reaction gas, and ejects the reaction gas supplied to a wind box 18 formed in the furnace body 11 below the gas dispersion plate 12. The reaction gas ejected from the nozzle 17 is
Particles of ore, which is the treated powder, are blown up into the space above the gas dispersion plate 12. A space further above the gas dispersion plate 12 is secured as an empty tower portion 19. Ore powder particles are blown up by the reaction gas ejected from the nozzle 17, and the fluidized bed 20 is formed. The height of the fluidized bed 20 is
The height of the fluidized bed 20 formed can be controlled by changing the flow rate according to the flow rate of the reaction gas flowing through the fluidized bed. The height of the partition plate 13 is equal to that of the fluidized bed 20.
Higher than the height of the fluidized bed 2 along the flow path 16.
Guide to ensure that 0 moves. The wind box 18
The reaction gas is supplied as a supply gas 21, and is discharged as an exhaust gas 22 from above the empty tower portion 19. Due to these reaction gases, the inside of the furnace body 11 is pressurized to, for example, several atmospheres, and the reaction gas contains, for example, a large amount of carbon monoxide (CO), and thus has airtightness. As such a pressure vessel, a cylindrical shape is preferable to a box shape.

FIG. 3 shows a simplified plan configuration of the second embodiment of the present invention, and FIG. 4 shows a cross section taken along the section line IV-IV of FIG. In this embodiment, it should be noted that the spiral partition plate 33 is erected on the gas dispersion plate 32 installed in the cylindrical furnace body 31, and the inlet 34 provided on the side wall of the furnace body 31.
Ore, which is a processed powder, is charged from the outlet 35 at the center.
Is to be discharged from. The flow path 36 in this embodiment is thus formed as a spiral from the outside to the inside along the partition plate 33. Nozzles 37 distributed on the gas distribution plate 32
From there, the reaction gas stored in the wind box section 38 gushes and forms a fluidized bed 40 while flowing to the upper empty space section 39 above. The fuel gas is supplied to the wind box section 38 as a supply gas 41,
The exhaust gas 22 is discharged from the top of the furnace body 31.

In the first embodiment and the second embodiment, the spiral flow paths 16 and 36 are formed, but their directions are reversed. In the first embodiment, since the inlet 14 is provided at the center of the furnace body 11, it is necessary to provide a chute 24 at the inlet 14 and charge the furnace body 11 from outside to the center.
However, since the outlet 15 is provided on the side wall of the furnace body 11, it is easy to carry it out after the treatment. In the second embodiment, the inlet 34 is provided on the side wall of the furnace body 31, so that the processing powder can be easily charged. However, since the outlet 35 is provided in the central portion, it is necessary to discharge the powder after processing through the chute 44 that penetrates the inside of the air box portion 38 downward. Therefore, it is necessary to provide the outlet of the chute 44 at the bottom of the furnace body 31, which increases the height of the entire apparatus. On the other hand, the inward spiral flow path 36 can form the gas dispersion plate 32 into a conical surface that is depressed on the inside, and large particles are mixed in the processing powder to be charged. Even if it accumulates on the gas dispersion plate 32, it can be easily discharged.

FIG. 5A shows a schematic plan structure of a third embodiment of the present invention. In the present embodiment, a cylindrical furnace body 51 is used.
Annular partitioning plates 53, 54, 5
5 are arranged concentrically. The partition plates 53, 54, 55 are partially cut out of the partition plates 53, 54, 55, respectively, such that the communication portions 57 are formed such that the flow path 56 is alternately formed in the circumferential direction and the radial direction. , 58 and 59 are respectively formed. The communicating portions 57, 58, 59 are arranged so as to be shifted on the same radius so as not to overlap. 180 °
It is preferable to shift by one. Further, as shown in FIG. 5 (B), the communication parts 57, 58, 59 are arranged while being slightly displaced from each other, and a partition is provided between one end of the inner partition plate and the other end of the outer partition plate. The flow paths 66 may be formed by connecting the plates 61, 62 and 63, respectively. As described above, similarly to the third embodiment shown in FIG. 5A and the fourth embodiment shown in FIG. 5B, the cylindrical furnace body 51 is used.
Channel 5 without dead zone by effectively utilizing the space inside
6,66 can be formed. The charging and discharging of the processing powder may be performed from the center and discharged from the outside as in the first embodiment, or may be performed from the center and discharged from the center.

Although each of the above embodiments has been described with reference to the production of eye anchor carbide, it can be effectively used for physical treatments such as heating, drying or granulation, and various chemical reaction treatments.

[0018]

As described above, according to the present invention, since the spiral partition is provided on the dispersion plate, the spiral flow path is formed in the cylindrical furnace body, and the space in the furnace body is effectively utilized. However, the processed powder can be efficiently processed without forming a dead zone.

Further, according to the present invention, a plurality of annular partitions are provided concentrically in a cylindrical furnace, and a curved flow path in which a circumferential direction and a radial direction are alternately repeated is formed to form a curved flow path inside the furnace. Effective processing of the processing powder can be performed while effectively preventing a dead zone from occurring in the space.

According to the present invention, the processing powder can be charged into the center of the cylindrical furnace body and discharged from the side wall. Since the discharge port is provided in the side wall portion, the processed powder processed in the fluidized bed furnace can be easily handled.

According to the present invention, since the processing powder is charged into the fluidized bed furnace from the side wall, the processing powder can be easily supplied from outside the furnace body. Since the treated powder after treatment is discharged from the center of the furnace body, for example, if the dispersion plate is provided with a conical slope such that the center is depressed, the treated powder deposited on the dispersion plate can be easily discharged. can do.

[Brief description of drawings]

FIG. 1 is a plan sectional view showing a schematic configuration of a first embodiment of the present invention.

FIG. 2 is a side cross-sectional view taken along the line II-II in FIG. 1;

FIG. 3 is a plan sectional view showing a schematic configuration of a second embodiment of the present invention.

FIG. 4 is a side cross-sectional view taken along a section line IV-IV in FIG. 3;

FIG. 5 is a schematic plan sectional view of a third and a fourth embodiment of the present invention.

FIG. 6 is a schematic plan sectional view of the prior art.

FIG. 7 is a graph showing the lapse of time in the fluidized bed furnace and the technology of the retained powder particles.

FIG. 8 is a simplified side view showing the configuration of a multistage fluidized bed furnace.

[Explanation of symbols]

 11, 31, 51 Furnace body 12, 32, 52 Gas dispersion plate 13, 33, 53, 54, 55 Partition plate 14, 34 Inlet 15, 35 Outlet 16, 36, 56, 66 Channel 17, 37 Nozzle 20, 40 Fluidized bed 57, 58, 59 Communication part

Claims (4)

[Claims] 1. A fluidized bed furnace in which a dispersion plate is provided in a cylindrical furnace body, and a gas is blown from below the dispersion plate to form a fluidized bed of treated powder on the dispersion plate. A fluidized bed furnace characterized by providing a partition of: 2. A fluidized bed furnace in which a dispersion plate is provided on a cylindrical furnace body, and a gas is jetted from below the dispersion plate to form a fluidized bed of treated powder on the dispersion plate. A fluidized bed furnace characterized in that annular partitions are concentrically provided, and each annular partition is formed with a communicating portion for communicating the inside and the outside on a radius different from that of an adjacent annular partition. 3. The fluidized bed furnace according to claim 1, wherein the cylindrical furnace body is provided with a treated powder charging port at a central portion and a treated powder discharging port at a side wall portion. . 4. The fluidized bed furnace according to claim 1, wherein the cylindrical furnace body is provided with a processing powder loading port at a side wall portion and a processing powder discharge port at a central portion. .