JPH06185705A - Fluidized-bed furnace - Google Patents

Abstract

PURPOSE:To execute an efficient baking of a raw material continuously by executing a circulation baking of the raw material between a baking zone and an overflowing zone through forming a furnace chamber of a space as the baking zone and the overflowing zone and setting a supplying opening for the raw material and the fuel which fronts the baking zone. CONSTITUTION:A fluidized-bed furnace 1 executes a baking by giving a fluidized condition to a raw material through usage of a gas in a furnace chamber 2 in a furnace body 1a. In this case, at an under portion of a furnace body 1a a product extracting opening 3 is arranged. Besides, in the furnace chamber 2 a bridgewall 7 is arranged, and between an under edge of this and a furnace chamber bottom face 5 a clearance 7a is made to stand. Further, on the furnace chamber bottom face 5 an inclination face 5a is formed which becomes higher as it executes more access to a side wall side. On the other hand, on the furnace chamber bottom face 5 which fronts a space between a bridgewall 7 and the inclination face 5a, a great number of openings 8a of a dispersing nozzle 8 are formed. And, the furnace chamber 2 of a space is formed as a baking zone A and an overflowing zone B, and a supplying opening for the raw material and the fuel which fronts the baking zone A is formed on a furnace body 1a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed firing furnace, and more specifically, it can effectively use, for example, industrial waste as a raw material or a fuel, and fires products such as lightweight aggregate continuously and efficiently. The present invention relates to a fluidized bed calcining furnace capable of being manufactured.

[0002]

2. Description of the Related Art In recent years, as buildings have become taller, there has been a demand for weight reduction of building materials for the purpose of weight reduction of steel frames. Therefore, artificial lightweight aggregates have been manufactured and used in place of conventional aggregates. The usage amount is increasing year by year. In addition, lightweight aggregates are starting to be used as artificial soil for rooftops of buildings and indoor gardens. On the other hand, the amount of industrial waste such as water and sewer sludge, fly ash discharged from coal boilers, waste plastics, etc. is increasing year by year, and the disposal method is becoming a social problem, and effective use of these wastes is being made. Practical application is an urgent task.

Therefore, in the production of lightweight aggregate, it is socially beneficial to develop an apparatus capable of utilizing all of these industrial wastes as raw materials and fuels. Conventionally, a method of crushing an effervescent shale and firing it in a rotary kiln has been used to manufacture a lightweight aggregate, which is still the mainstream. In recent years, a method has been put into practical use in which fly ash and clay generated from a coal-fired power plant are mixed and granulated, and the coal is burned in a moving-grate method as a fuel.

[0004]

In the firing method using the rotary kiln or the moving grate, the equipment area occupies a large amount and the fuel / electric power consumption rate is large. In addition, when waste fuel is used, it is difficult to maintain the quality as a lightweight aggregate because a large amount of unburned matter is mixed in the product. On the other hand, if a calcination system using a fluidized bed is used, the equipment area can be reduced and waste can be used as fuel. However, continuous calcination mixes uncalcined products into the product. Therefore, it is necessary to perform batch operation, but in that case, there is a problem that heat loss due to repeated temperature rising and cooling of the fluidized bed is large, and the fuel / electric power consumption rate is significantly deteriorated.

The present invention has been made in view of the above circumstances, and it is possible to effectively use, for example, industrial waste as a raw material and a fuel, and to burn products such as lightweight aggregate continuously and efficiently. The purpose of the present invention is to obtain a fluidized bed calcining furnace capable of performing the above.

[0006]

In order to achieve the above object, the fluidized bed calcining furnace of the present invention is a fluidized bed calcining furnace in which a raw material is fluidized with a gas in a furnace chamber in a furnace body and calcined. hand,
A product outlet that opens to the bottom of the furnace chamber is provided at the bottom of the furnace body,
The furnace chamber is provided with a partition wall whose lower end is spaced from the bottom of the furnace chamber and is located closer to the side wall of the furnace body than the product outlet, and goes to the side wall of the furnace body at the bottom of the furnace chamber on the side wall of the furnace body. Forming a sloping surface which becomes higher, and providing a number of dispersion nozzles on the bottom surface of the furnace chamber facing the space between the partition wall and the sloping surface of the bottom surface of the furnace chamber so that fluidized gas is supplied to the space, The furnace chamber of the space is formed as a firing zone, and the furnace chamber of the space which is defined by the partition wall and faces above the opening of the product outlet is formed as an overflow zone. Was provided so as to face the firing zone.

[0007]

The waste such as sludge as a raw material to be fired is, for example, granulated to have a predetermined particle size, and then supplied to the firing zone of the fluidized bed firing furnace. Waste materials such as coffee grounds are also supplied to the firing zone as fuel. In the firing zone, a high temperature gas as a fluidizing gas is blown up and supplied from a gas dispersion nozzle on the bottom of the furnace chamber facing the firing zone, and the fuel and the raw material to be fired are vigorously mixed and fluidized to form a fluidized bed. The fuel is burned, and the high heat burns the raw material to be burned.

[0008] Thus, the raw material is fired in the firing zone to expand and foam and the apparent specific gravity is reduced (for example, 0.6 times or less of the raw material), and the products gather on the surface layer of the fluidized bed. Since the bottom surface of the furnace chamber on the side wall of the furnace is formed with an inclined surface that is higher toward the side wall of the furnace, the cross-sectional area in the firing zone becomes larger as it goes upward, and the fluidized bed is formed in the lower and upper parts of the firing zone. There is a difference in the flow velocity of the gas passing through, and the flow velocity of the gas becomes smaller toward the upper part of the fluidized bed, and the flow velocity at the surface layer part of the fluidized bed becomes, for example, 1/2 of the lower part. Therefore, in the fluidized bed of the calcination zone, the product which is a calcined product having a smaller apparent specific gravity as described above is separated from the raw material having a large apparent specific gravity or the unsintered product (semi-sintered product), and the raw material having a large apparent specific gravity or the unsintered product The product remains in this firing zone and is further fired in the fluidized bed.

On the other hand, although the flow velocity is low in the surface layer portion of the fluidized bed in the firing zone, the apparent specific gravity of the product is low, so that the product scatters and part of the unfired product is mixed into the partition wall. It jumps over and flows into the adjacent overflow zone. At this time, the unfired product particles have a larger apparent specific gravity and a smaller height than the product particles, so that they flow into the overflow zone in the vicinity of the partition wall and flow down in the vicinity of the partition wall. Further, since the product particles have a small apparent specific gravity and a large flying height, they fly further and flow into the central portion of the overflow zone to flow down to flow into the opening of the product outlet located below the overflow zone. It is extracted from the furnace through the outlet.

On the other hand, the fluidized bed of raw materials, unsintered products, products and fuel in the calcination zone has a low apparent specific gravity because it is fluidized and contains air. On the other hand, the overflow zone is a moving bed that descends and the air. Since (gas) hardly flows, the apparent specific gravity is large. Therefore, particles are circulated from the overflow zone having a large apparent specific gravity to the firing zone having a small apparent specific gravity through the gap between the lower end of the partition wall and the bottom surface of the furnace chamber.

However, this circulation exists in the overflow zone between the product outlet and the partition wall because the partition wall is installed closer to the side wall of the furnace than the product outlet. Particles, that is, the unburned product particles flowing down near the partition wall in the overflow zone, come into contact with the violently fluidized fluidized bed of the firing zone in the gap portion and are entrained in the fluidized bed to the firing zone. It is done by inflow. The unfired product particles that have flowed into the firing zone are then subjected to further firing. In this way, the unfired product is circulated and fired between the firing zone and the overflow zone to continuously perform the firing action.

In the firing zone, the above-mentioned circulation action is performed more smoothly by the inclined surface. Further, if the inclined surface is an inclined surface that is inclined at an angle of repose or more of the raw material, the raw material in the fluidized bed will not stay on the inclined surface, and the fluidized firing will be performed efficiently.

[0013]

The present invention will now be described in detail with reference to the embodiments shown in the drawings. FIG. 1 is a vertical sectional front view showing an overall schematic structure of a fluidized bed firing furnace of the present invention, FIG. 2 is an enlarged vertical sectional front view of a main part of the furnace main body of FIG. 1, and FIG. 3 is a vertical sectional side view taken along line III-III of FIG. FIG. 4 is a system diagram of an apparatus for manufacturing a lightweight aggregate using the firing furnace of the present invention.

First, the fluidized bed firing furnace will be described with reference to FIGS. In this embodiment, the cross section of the furnace body is rectangular and the firing zones are provided on both sides of the overflow zone.
Reference numeral 1 is a fluidized bed firing furnace, 1a is a furnace body, 2 is a furnace chamber, and 5 is a bottom surface of the furnace chamber. As shown in FIG. 1 or FIG. 2, at the center of the lower portion of the furnace main body 1a, a product outlet 3 is provided which is opened in a horizontal plane 5b portion of the furnace chamber bottom surface 5 which will be described later. The product outlet 3 is formed over the entire width of the furnace chamber 2 in a side view as shown in FIG. Further, the upper end edge 3b of the opening of the product outlet 3 on the inner wall surface 3a side is a horizontal surface 5
The required amount has been raised from b. Further, air chambers 4 are provided on both sides of the product outlet 3 through a furnace body forming a furnace chamber bottom surface 5 at the bottom of the furnace body 1a. Air chamber 4
An air supply port 4a is formed in the.

The bottom surfaces 5 of the furnace chamber are provided on the left and right sides of the product outlet 3 in a front view, and each bottom surface 5 of the furnace chamber is a horizontal surface 5b located on the side of the product outlet 3 and is continuous with the horizontal surface 5b. The inclined surface 5a is formed so that it becomes higher toward the side wall of the furnace body 1a. That is, the inclined surfaces 5a are formed on both side walls of the furnace body 1a in a front view. Partition walls 7, 7 are provided at symmetrical positions on the left and right sides of the product outlet 3 in the furnace chamber 2, respectively, and the partition walls 7, 7 are respectively closer to the side wall of the furnace body 1 a than the product outlet 3, that is, In a front view of the product outlet 3 shown in FIG. 2, the product outlet 3 is provided closer to the side wall of the furnace body 1a than the inner wall surface 3a by a predetermined distance, and the lower end of the product outlet 3 is provided with a horizontal surface 5b of the furnace chamber bottom surface 5 and a gap 7a. ing. The upper ends of the partition walls 7, 7 are bent toward the side wall of the furnace body 1a on the side where they are located.

The furnace chamber bottom surface 5 facing the space of the furnace chamber 2 surrounded by the inclined surface 5a of the furnace chamber bottom surface 5 and the horizontal surface 5b and the partition wall 7 on the left and right sides of the product outlet 3 is the furnace chamber bottom surface 5. The furnace body forming the chamber bottom surface 5 is provided with the tip openings 8a of a large number of dispersion nozzles 8 penetrating vertically so that the air in the air chamber 4 is supplied to each of the spaces. It is configured. In addition, left and right horizontal planes 5b
At the position closer to the product outlet 3 side than the partition plate 7, the dispersion nozzle 8b is also located, and a cap is attached to this upper end opening so that air is ejected toward the space. ing.

With the lower part of the furnace chamber 2 constructed as above, the inclined surfaces 5a of the bottom surface 5 of the furnace chamber at the symmetrical positions with respect to the product outlet 3 as viewed from the front of the furnace. The space of the furnace chamber 2 surrounded by the horizontal surface 5b and the partition wall 7 is formed as a firing zone A. The space of the furnace chamber 2 located above the product outlet 3 in the center of the furnace and sandwiched by the partition walls 7 is formed as an overflow zone B. That is, the firing zones A are formed on both sides of the overflow zone B.

A raw material and fuel supply port 9 is attached to the side wall of the furnace body 1a so as to face the firing zone A. Further, an exhaust gas discharge port 10 is provided at the upper end of the furnace main body 1a via an empty column portion F above the firing zone A and the overflow zone B.

On the other hand, a product withdrawal pipe 11 is attached to the product withdrawal outlet 3 of the firing furnace body 1a so as to be connected to the lower end 3c thereof, and the product withdrawal valve 15 is attached to the lower end thereof.
Is installed. A water jacket 13 is provided around the outer wall surface of the product discharge pipe 11. Further, inside the product withdrawal pipe 11, a ring pipe 14 around which a cold air supply nozzle is arranged is provided in the lower part, and the heat transfer pipe 1 is provided above the ring pipe 14.
2 are installed.

Next, a lightweight aggregate manufacturing apparatus using the fluidized bed firing furnace 1 configured as described above will be described with reference to FIG. In FIG. 4, the raw material and fuel supply ports 9 of the firing furnace 1
A feed passage M for the raw material and a feed passage L for the fuel that are subjected to the firing action are connected to the. A raw material tank 20, a mixer 21, a granulator 22, and a dryer 23 are arranged in this order from the upstream side in the raw material supply path M.
Is installed. A fuel tank 24 and a dryer 25 are provided on the fuel supply path L from the upstream side. Further, the air supply port 4a of the air chamber 4 of the fluidized bed firing furnace 1
A preheating furnace 40 for preheating the fluidized bed at the time of starting is connected to the. Waste oil is used as fuel in the preheating furnace 40. An air supply blower 33 is connected to the ring pipe 14 of the product withdrawal pipe 11.

An air preheater 30 is provided in the exhaust gas exhaust pipe connected to the exhaust gas exhaust port 10 of the fluidized bed firing furnace 1, and a part of the air of the air supply blower 33 is provided in the exhaust gas exhaust pipe by a conduit 31. The high-temperature air that has been supplied and preheated and that has been preheated is supplied to the air chamber 4 through the conduit 32. The exhaust gas discharged from the air preheater 30 is further supplied to the raw material dryer 23 and the fuel dryer 25, and after being discharged from these, is introduced into the bag filter 34 to collect dust, and is exhausted from the chimney 36 through the induction fan 35. It is configured to be. The heat recovery unit C in FIG. 1 corresponds to the air preheater 30 and the dryers 23 and 25, and the dust collection unit D
Corresponds to the bag filter 34.

Next, the operation of the fluidized bed firing furnace 1 configured as described above will be described. In this embodiment, water purification sludge as industrial waste, magnesium oxide powder, waste silica sand, and fly ash are used as raw materials to be burned, and these are stored in the raw material tank 20. On the other hand, as the fuel for firing, coffee grounds and waste plastic, which are also industrial wastes, are used, which are stored in the fuel tank 24.

The water treatment plant sludge, magnesium oxide powder, waste silica sand, and fly ash as raw materials are introduced into the mixer 21 from the raw material tank 20 and mixed, and then introduced into the granulator 22 where predetermined particles are introduced. Granulate to a diameter (for example, 10 to 20 mm). The granulated raw material is introduced into the dryer 23, dried with the exhaust gas of the firing furnace 1 to remove a predetermined amount of water, and then the firing furnace 1
Is conveyed to the small hopper 26 and is fed into the firing zone A of the furnace chamber 2 of the firing furnace main body 1a from the raw material / fuel supply port 9.
On the other hand, coffee grounds and waste plastics as fuel are introduced from the fuel tank 24 into the dryer 25, dried by the exhaust gas of the baking furnace 1 to remove a predetermined amount of water, and then transferred to the small hopper 26 in the same manner as the above-mentioned raw material. Then, the material is introduced into the firing zone A of the furnace chamber 2 of the firing furnace main body 1a from the raw material supply port 9.

Thus, the firing zone A of the fluidized bed firing furnace 1
Then, high temperature air is supplied to the firing zone A from the lower air chamber 4 through the upper end openings 8a of a large number of dispersing nozzles 8 and 8b provided on the bottom surface 5 of the furnace chamber, and is jetted to fluidize the raw material and fuel. A fluidized bed is formed, in which the raw material and the fuel are vigorously agitated and the fuel is burned by the hot air so that the fluidized bed has a high calcination temperature (e.g.
It is kept at 1200 ℃. As a result, sludge and magnesium oxide powder as raw materials, waste sand, and fly ash are fired, that is, Fe ₂ O ₃ , carbonates, sulfides, sulfates and the like contained in these raw materials are represented by, for example, the formula [3Fe ₂ O ₃ → 2Fe ₃ O ₄ +
(1/2) O ₂ ↑] decomposes by heat,
With _{O 2, CO 2, SO 2} , SO 3 , etc. of the gas is produced is vitrified at high temperature, the generated gas is expanded foamed by being confined inside, the product is produced is lightweight aggregate It

In the present embodiment, the inclined surface 5a of the firing zone A is a slope inclined above the repose angle of the raw material, so that the raw material in the fluidized bed does not stay on the slope and the fluidized firing is efficient. It is done well. Further, a small amount of air is supplied from the opening 8a of the dispersion nozzle 8 provided on the inclined surface 5a to the extent that the raw material is not accumulated on the inclined surface 5a. The air chamber 4 is supplied with high-temperature air (for example, 600 ° C.) preheated by the air preheater 30 from the pipe 32. Further, at the time of starting the furnace, the preheating furnace 40
To supply hot air to preheat the fluidized bed.

Since the product baked in the baking zone A is expanded and foamed, it has a small apparent specific gravity (for example, 0.6 times or less of the raw material) and collects on the surface layer of the fluidized bed. Further, the bottom surface 5 of the furnace chamber on the side wall side of the furnace body 1a
The cross-sectional area in the firing zone A becomes larger as it goes upward due to the formation of the inclined surface 5a which becomes higher toward the side wall side, and the gas passing through the fluidized bed in the lower portion and the upper portion of the firing zone A is increased. Due to the difference in the flow velocity, the gas flow velocity becomes smaller toward the upper part of the fluidized bed, and the flow velocity at the surface layer part of the fluidized bed becomes smaller, for example, 1/2 of the lower part. Therefore, in the fluidized bed of the calcination zone A, a product which is a calcined product having a small apparent specific gravity as described above and a raw material or an unsintered product (semi-sintered product) having a large apparent specific gravity are separated,
The raw material or unfired product having a large apparent specific gravity remains in the firing zone A and is further fired in the fluidized bed.

On the other hand, although the product gathered in the surface layer of the fluidized bed in the firing zone A has a small gas flow velocity in the surface layer, the product has a small apparent specific gravity and the surface layer has a small specific gravity. Since it exhibits a severe undulation phenomenon, it scatters and mixes a part of the unfired product, jumps over the upper ends of the partition walls 7 and flows into the adjacent overflow zone B. During the scattering and inflow, since the upper ends of the partition walls 7 and 7 are bent toward the firing zone A, unfired product particles having an apparent specific gravity larger than that of the product are as much as possible at the bends. It is blocked and promotes the retention of unfired product particles in the firing zone A and promotes the firing action.

As for the inflow into the overflow zone B, however, the unfired product particles E have a larger apparent specific gravity and a smaller jump height than the product particles, so that the partition walls 7 and 7 of the overflow zone B have a small height. It flows into the vicinity and flows down here. Further, since the product particles P have a small apparent specific gravity and a large jump height, they fly further and flow into the central portion of the overflow zone B to flow down to the opening of the product outlet 3 located below the overflow zone B. It flows in, descends the product outlet 3, and flows into the product outlet pipe 11.

On the other hand, the fluidized bed of raw materials, unsintered products, products and fuel in the calcination zone A has a small apparent specific gravity because it is fluidized and contains air, while the overflow zone B is a moving bed that descends. There is almost no air (gas) flowing, so the apparent specific gravity is large. Therefore, as indicated by the arrow in the figure, the gap 7 between the lower ends of the partition walls 7 and 7 and the furnace chamber bottom surface 5 is
Particles are circulated from the overflow zone A having a large apparent specific gravity to the firing zone B having a small apparent specific gravity through a.
In this circulation, the partition walls 7, 7 are the inner wall surface 3a of the product outlet 3.
The particles existing in the overflow zone B between the inner wall surface 3a of the product outlet 3 and the partition wall 7, that is, the overflow, by being installed closer to the side wall of the furnace body 1a than Unfired product particles E flowing down in the vicinity of the partition wall 7 in the zone B
Is brought into contact with the fluidized bed in the firing zone A which is vigorously fluidized in the gap 7a, is caught in the fluidized bed and flows into the firing zone A.

In this embodiment, the inner wall surface 3a of the product outlet 3 is
Since the upper edge 3b of the side opening is raised,
The unfired product particles E are directed to the gap 7a side, and the firing zone A
The inflow and circulation of the unburned product particles E into the product withdrawal port 3 are effectively prevented. Further, air is blown from the overflow zone B side toward the firing zone A through the gap 7a from the upper end opening 8a of the dispersion nozzle 8b provided near the gap 7a toward the overflow zone B side. The flow of the unfired product particles E into the firing zone A through the gap 7a is promoted and promoted.

The unfired product particles E flowing into the firing zone A are further subjected to firing here. Thus, the unfired product is circulated and fired between the firing zone A and the overflow zone B, and the firing action is continuously performed. In addition, in the firing zone A, the circulation action is more smoothly performed by the action of the inclined surface 5a.

On the other hand, the product flowing from the product outlet 3 into the product outlet pipe 11 forms a moving layer by the operation of the product outlet valve 15 at the lower end and descends. However, since the product is heated to a high temperature, air is supplied. The cold air sent by the blower 33 is supplied from the cooling air supply nozzle of the ring pipe 14 into the product extraction pipe 11 to cool the product, and at the same time, the water flowing through the heat transfer pipe 12 absorbs heat to cool the product. To be done. At the same time, it is cooled by the water jacket 13 outside the product withdrawal pipe 11. In this way, the product withdrawal pipe 11 also functions as a product cooling device. Further, the product is cooled inside the product withdrawal pipe 11 by heat transfer in the moving bed.

As described above, in the present embodiment, the product is dropped from the product withdrawal outlet 3 of the firing furnace 1 to the product withdrawal pipe 11 which also serves as a cooling device by gravity, so that the product is transferred to a separate cooling device. Since a device such as a conveyer is not required and cooling uses moving bed heat transfer, the cooling air amount can be small and the heat transfer area can be small. Therefore, the equipment area of the calcining device can be further reduced in addition to the fluidized bed system as the calcining method.

The combustion exhaust gas discharged from the calcination zone A rises in the empty tower part (freeboard) F of the furnace chamber 2 together with the air used for cooling inside the product discharge pipe 11 and the exhaust gas discharge port 10 From the furnace to the outside of the furnace, and as described above, the exhaust heat recovery section C (air preheater 30, raw material, fuel dryers 23, 2
5) and the dust collecting part D (bug filter 34) and then the chimney 36
Emitted into the atmosphere.

Next, the results of the actual firing test of the lightweight aggregate using the apparatus of the embodiment shown in FIGS. 1 to 4 will be described. As raw materials, water purification plant sludge, magnesium oxide (MgO) powder, waste silica sand, and fly ash, which are industrial waste, are used. For example, 40% of water purification plant sludge and magnesium oxide (MgO) powder exhibiting foamability 2%, waste silica sand 18%, and fly ash 40% were cut out from the raw material tank 20 and mixed. This is supplied to the mixer 21 for mixing, and further supplied to the granulator 22 to adjust the particle size to 10 ~.
The length was set to 20 m, and this was put into the raw material dryer 23, dried with the exhaust gas of the fluidized bed firing furnace 1, and supplied to the fluidized bed firing furnace 1.

On the other hand, industrial waste such as coffee grounds and waste plastics are used as fuel, supplied from the fuel tank 24 to the fuel dryer 25 for drying, and continuously supplied to the fluidized bed firing furnace 1 together with the raw materials. The fuel was burned in the fluidized bed firing furnace 1 to burn the raw material. The firing temperature at this time is 1100
The firing time at ~ 1200 ° C was 10-30 minutes. The baked product is a product discharge pipe 11 (cooling device) under the fluidized bed baking furnace 1.
Cooled to 100 ° C. The cooling water of the heat transfer tube 12 and the water jacket 13 at that time was collected with hot water or steam. The resulting lightweight aggregate has the following properties: apparent specific gravity 0.7, crushing load 50Kgf / cm ² or more, 24-hour water absorption 10.6.
%, And excellent quality lightweight aggregate was obtained.

Heat recovery from the exhaust gas of the fluidized bed firing furnace 1
This was carried out by preheating the flowing / combustion air to 600 ° C. by the air preheater 30 and utilizing it for drying the raw materials and fuel by the raw materials and the fuel dryers 23 and 25.
Further, preheating of the apparatus at the time of startup was performed by burning waste oil in the preheating furnace 40 and using the combustion exhaust gas. Although not used in this embodiment, heat may be further recovered from the exhaust gas by an exhaust heat boiler.
As described above, it was found that the fluidized bed firing furnace 1 of the present embodiment can be used as a device capable of effectively producing industrial waste as a raw material and a fuel to produce a useful lightweight aggregate.

Next, another embodiment of the fluidized bed firing furnace of the present invention will be described with reference to FIGS. 5 is an enlarged vertical sectional front view of the main part of the firing furnace main body, and FIG. 6 is a vertical sectional side view taken along the line VI-VI of FIG. The same reference numerals are used for the same or corresponding portions as those in FIGS. 1 to 3, and the description thereof will be omitted. In the fluidized bed firing furnace 1A of this embodiment, the cross section of the furnace body 1a is rectangular, the partition walls 7 are attached to the furnace chamber 2 at one location (one sheet), and the firing zones A are provided on both sides of the partition wall 7. Overflow zones B are formed one by one. The product outlet 3 is attached along one side wall side in a front view as shown in FIG. 5, and the overflow zone B is defined by the partition wall 7 and is a space of the furnace chamber 2 facing above the opening of the product outlet 3. Is formed in.

Even in the fluidized bed firing furnace 1A having such a structure, it is possible to continuously and efficiently perform the firing operation as in the fluidized bed firing furnace 1 shown in FIGS. The firing furnace of this embodiment is preferably used when the firing capacity is smaller than that of the fluidized bed firing furnace 1 shown in FIGS.

Next, still another embodiment of the fluidized bed firing furnace of the present invention will be described with reference to FIGS. 7 is an enlarged vertical sectional front view of the main part of the firing furnace main body, and FIG. 8 is VIII to VI of FIG.
It is a cross-sectional plan view taken along the line II. The same reference numerals are used for the same or corresponding portions as those in FIGS. 1 to 3, and the description thereof will be omitted. In the fluidized bed firing furnace 1B of this embodiment, as shown in FIG. 8, the furnace body 1a has a circular cross section, and therefore the furnace chamber 2 also has a circular cross section. The product outlet 3 has a circular cross section and is provided concentrically with the furnace body 1a at the center (center) of the lower part of the furnace body 1a. In the furnace chamber 2, a tubular partition wall 7 is positioned concentrically with the furnace main body 1a and the product outlet 3 and is attached to the side wall of the furnace main body 1a by a supporting member 7b. The inner diameter of the tubular partition wall 7 is It is formed to be larger than the inner diameter (inner wall surface 3a) of the product outlet 3 by a predetermined amount.

The bottom 5 of the furnace chamber is formed as an annular bottom around the product outlet 3, and the openings 8a of the gas dispersion nozzles 8 are scattered around the bottom. Furnace body 1a
An annular air chamber 4 is formed around the product outlet 3 at the lowermost part. Thus, the furnace chamber 2 in the internal space of the tubular partition wall 7 is formed as a cylindrical overflow zone B, and the furnace chamber 2 in the space around the overflow zone B is formed as an annular fluidized firing zone A. To be done. Even in the fluidized bed firing furnace 1B having such a configuration, it is possible to continuously and efficiently perform the firing operation.

In the above embodiment, the upper end of the partition wall 7 is bent, but of course, it may be straight without being bent. Further, the raw material and the fuel are simultaneously supplied into the furnace chamber 2 from the same location through the supply port 9 of the furnace main body 1a, but the raw material and the fuel are separately supplied, for example, in the upper part of the fluidized bed of the firing zone A, respectively. It may be supplied inside the fluidized bed.

[0043]

As is clear from the above description, according to the fluidized bed firing furnace of the present invention, the raw material can be circulated between the firing zone and the overflow zone to be fired, so that an unfired product is eliminated. The raw material can be continuously and efficiently fired. In addition, because of the combustion and firing by the fluidized bed,
Fuel combustion efficiency and heat transfer to firing raw materials are good, and effective use of industrial waste such as sludge and coffee meal as firing raw materials and firing fuels, respectively, to effectively obtain lightweight aggregates as products. You can Further, the installation area of the firing furnace can be made smaller than that of the conventional rotary kiln or moving grade method.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing an overall schematic structure of a fluidized bed firing furnace of the present invention.

FIG. 2 is an enlarged vertical sectional front view of a main part of the firing furnace main body of FIG.

FIG. 3 is a vertical sectional side view taken along the line III-III of FIG.

FIG. 4 is a system diagram of a lightweight aggregate manufacturing apparatus using the fluidized bed firing furnace of the present invention.

FIG. 5 is an enlarged vertical sectional front view of a main part of a firing furnace body according to another embodiment of the present invention.

FIG. 6 is a vertical sectional side view taken along the line VI-VI of FIG.

FIG. 7 is an enlarged vertical sectional front view of a main part of a firing furnace main body according to still another embodiment of the present invention.

8 is a cross-sectional plan view taken along the line VIII-VIII of FIG.

[Explanation of symbols]

 1, 1A, 1B Fluidized bed firing furnace 1a Furnace body 2 Furnace chamber 3 Product outlet 3a Inner wall surface (product outlet) 3b Opening upper edge (product outlet) 4 Air chamber 5 Furnace chamber bottom 5a Inclined surface 5b Horizontal surface 7 Partition Wall 7a Gap 8 Dispersion nozzle 8a Dispersion nozzle opening 9 Raw material / fuel supply port A Firing zone B Overflow zone E Unfired product particle P Product particle

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location F23G 5/30 ZAB S 7815-3K F27B 15/00 7516-4K

Claims (1)

[Claims] 1. A fluidized bed firing furnace in which a raw material is fluidized with a gas in a furnace chamber in a furnace body and fired, wherein a product outlet opening to the bottom of the furnace chamber is provided at the bottom of the furnace body, A partition wall is provided whose lower end is spaced from the bottom of the furnace chamber and is positioned closer to the side wall of the furnace body than the product outlet, and the bottom of the furnace chamber on the side wall of the furnace body becomes higher toward the side wall of the furnace body. An inclined surface is formed, and a large number of dispersion nozzle openings are provided on the bottom surface of the furnace chamber facing the space between the partition wall and the inclined surface of the bottom surface of the furnace chamber so that fluidized gas is supplied to the space. The furnace chamber of the space is formed as a firing zone, and the furnace chamber of the space which is defined by the partition wall and faces above the opening of the product outlet is formed as an overflow zone, and a feed port for the raw material and fuel is provided in the furnace body. A fluidized bed firing furnace provided so as to face the firing zone.