JPS62237939A - Multistage jet stream bed apparatus using peripheral wall jet stream type fluidized bed - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention forms a fluidized bed and a spouted bed of rising air and powder and granules in a vertical cylindrical vessel, drying, preheating, roasting,
This invention relates to a multi-stage spouted bed device that performs processes such as sintering reactions and cooling.

One point to note - Devices using fluidized beds and spouted beds have excellent heat transfer properties, but on the other hand,
Because it is a complete mixing type, its thermal efficiency and reaction rate are low, which is a structural disadvantage.

Therefore, in order to improve this problem, it is considered that the ideal form of this type of device is to make the rising air current and the flow of the powder material countercurrent and to form multiple layers.

A typical example of a conventionally proposed device for forming a fluidized bed or a spouted bed in multiple stages is shown in FIG. This device is fed in one stage as shown by the arrow, and the saw powder is gradually processed in each stage, and furthermore, an overflow pipe 12.12",
12'' to the lower stage, and is then discharged from the discharge port 13.

On the other hand, the rising air current is supplied from the inlet 14, distributed and supplied to the perforated plates 15, 15', 15', and 15' in each stage, and then discharged from the outlet 16.

In general, in a multi-stage fluidized bed apparatus (including a spouted bed apparatus), the powder and granules are brought into contact with an ascending air flow in countercurrent flow, and a fixed amount of the powder is transferred to the lower stage without forming a fluidized bed at each stage. The biggest drawback lies in the sending mechanism. Furthermore, as shown in Figure 2 above, a multi-stage fluidized bed device that uses a perforated plate as the bottom plate of each stage is difficult to put into practical use because it does not exhibit a stable fluidized bed state except in a certain limited operating area. Therefore, in practice, we are forced to abandon countercurrent flow and develop horizontal multi-nitriding.

On the other hand, the present inventor previously proposed and put into practical use an empty tower type multistage jet (flow) device in Japanese Patent Publications No. 59-11334, No. 6-22273, and No. 60-22274. This device advances multi-stage countercurrent flow without using two perforated plates, but it is difficult to have more than two stages, so the temperature of the exhaust gas in the rising air is still high. There was a need for more efficient heat recovery.

Therefore, as a result of various studies, the present inventor found that in order to realize the above-mentioned physical form, the amount of granular material retained in the fluidized bed (spouted bed) must be reduced without changing the amount of updraft (hereinafter referred to as gas amount). Focusing on the fact that it is possible to easily control the increase and decrease, and that it is necessary to send a fixed amount to the lower stage, the earlier application (Japanese Patent Application No. 61-25
787) (hereinafter referred to as the "prior application").

In other words, adjusting the amount of powder and granules that stays in a multi-stage fluidized bed (spouted bed) and the amount that falls to the lower stage is mainly related to the flow velocity of the updraft that blows up, so to change the flow velocity, increase or decrease the gas amount. However, in the previous application, an opening with a variable area structure was provided in the peripheral wall to create a peripheral wall jet type.
Even if the gas beads are constant, the flow velocity of the rising air current can be changed, and the amount of retention and amount of falling air can be easily controlled.

In general, the density of powder particles that stay in a fluidized bed (spouted bed) is expressed by the formula (1
), and the falling amount of each stage is proportional to the amount of granular material retained according to equation (2), and is inversely proportional to the flow velocity of the upward air current.

W-Δp-AT...(1).

W: Retention amount (kg) △p: Rise in the fluidized bed of powder and granules Airflow pressure loss (kg/m2) Cross-sectional area of AT/fluidized bed device cylindrical vessel (m2) FcAw/u' ・-・+-(2).

F: Fall nk (kg/5ac) W: Stagnant amount (kg) U, Flow velocity (m/5lc) In other words, an amount equivalent to the pressure loss (△p) of the rising air flows floatingly, but the raw material of the powder and granular material If it is continuously supplied, the balance of equation (1) above will be disrupted, and an amount proportional to the amount supplied will fall so as to be automatically pushed out from the opening.

Therefore, according to the above-mentioned open area drop method with a variable area structure, there is no need to forcibly drop the falling amount (change the amount of debris) at each stage. If it is possible to change the area of the opening (falling part), the blow-off flow rate will change and the falling amount will change accordingly, so a new stagnation amount will be formed under a constant raw material supply rate. The following relationship holds true: change in area - change in flow velocity - change in Δp - change in retention.

In contrast, the fluidized bed device of the earlier application uses a fluidized bed bottom plate, and has multiple openings of 1" between the bottom plate and the inner circumferential wall of the cylindrical vessel. This method forms layers.

However, in this method, although the formation of a fluidized bed (spouted bed) is stable, the amount of powder particles staying in each layer is dense and the fluidized state may not be in a vigorously agitated state.

In such a case, if the sinterable material is subjected to processing such as firing, the material may fuse together and clinker may be formed, which may make operation impossible.

Therefore, the present inventor was able to solve this problem by forming a "single-wall spouted fluidized bed" and a "cavity spouted bed" in which the powder and granules are in a vigorously agitated jet state above and below.

In a device used to form a fluidized bed and a spouted bed of an ascending air flow and powder and granules in a vertical cylindrical container, a gap between the peripheral wall and the bottom plate of the fluidized bed is formed along the inner peripheral wall of the cylindrical container. An opening with a variable area structure is provided to blow up the rising air, and a cylindrical jet chamber is installed below the opening, and the cylindrical jet chamber is connected to an air flow inlet provided directly below it. A multi-stage spouted bed device using a peripheral wall spout type fluidized bed, characterized in that a powder discharge port 1 is provided through the opening, and a powder supply port and an air flow discharge port are provided above the opening. It is.

The structure and operation of the present invention will be explained below based on examples.

Friend jllJ FIG. 1 is a side sectional view of a multi-stage spouted bed apparatus embodying the present invention. In the figure, I is a vertical cylindrical vessel forming the main body of the multi-stage spouted bed device, 2 is a supply port for raw material powder, 3 is a powder discharge port, and 4.4'.

4'' is an airflow inlet, and 5 is an airflow outlet.

Next, 6.6°, 6" is the fluidized bed bottom plate, 7,7" is the area adjustment device of openings 8,8" for blowing up the upward airflow, and openings 8 to 8" is formed along the circumferential surface between the fluidized bed bottom plate 6~6'' and the inner circumferential wall of the cylindrical vessel 1.

A cylindrical jet chamber 9 is provided directly below the opening 8.

The powder and granular material supplied into the device as shown by arrow C enters the opening 8.
A fluidized bed and a spouted bed are formed by the updraft blowing at ~8".

Here, a fluidized bed generally refers to a layer in which particles are suspended in a relatively low-velocity updraft, and a spouted bed is different from a spouted bed.
This refers to the formation of a fountain-like layer of suspended particles due to high-speed updrafts.

In this invention, the upward flow velocity of the rising air in the openings 8 to 8''' is more likely to be a condition for forming a spouted layer than in the conventional blowing from the opening 1] (porous part) using a perforated plate. Therefore, in general, suspended fluidity of particles tends to be in a violently agitated state, which is effective for the above-mentioned treatments such as reactions and roasting.

Further, at a portion slightly away from the openings 8 to 8'', the flow rate is slow and a fluidized bed is formed, so the amount of powder particles staying there becomes dense.

Next, a description will be given of the mechanism by which particles stay in the fluidized bed and the spouted bed in this embodiment, and how they fall through the openings 8 to 8''.

FIG. 3 is a partially enlarged view of the fluidized bed bottom plate 6, area adjustment device 7, and opening 8 shown in FIG. FIG. 4 is a sectional view taken along line AA' in FIG. In this embodiment, the area adjusting device 7 has six area adjusting plates 7a to 7f as shown in FIG. [Nitsuba] It is sandwiched between a and is slidably attached so that it can be operated from the outside. Note that the collar 1a is kept airtight around the entire circumference by a gasket.

Even during operation of the multi-stage spouted bed device, the area adjustment devices 7a~
If 7f is pushed into the cylindrical container 1, the cross-sectional area of the opening 8 will be narrowed by that amount, and if it is pulled out, it will be widened by that amount.

Further, reference numeral 11 in FIGS. 3 and 4 is a member that fixes and supports the fluidized bed bottom body 6.

The opening area of the most open part 8'' in FIG. If it is movable, it can be adjusted freely.

Next, the amount of powder particles supported by the upward air flow in the opening 8 (including 8° and 8" in Figure 1) has the relationship explained in equation (1) above, and the amount of powder particles remaining The amount by which the particles fall has the relationship as explained in equation (2).

Therefore, if we keep the area of the opening 8~8゛ constant and the flow velocity of the air current constant (constant gas amount), the amount of powder particles retained will be the amount balanced by equation (1), and the powder will continue to flow. If granules are supplied, they will continue to fall as much as the amount of stagnation increases (
(balanced using equation (2)). Therefore, if the area of the openings 8 to 8'' is constant, the amount of retention cannot be adjusted unless the amount of gas is increased or decreased.

However, according to this embodiment, even if the gas amount is kept constant, the area adjustment plate 7a of the area adjustment device 7 or the elevator 1
0 can adjust the area of the opening 8~8'',
The flow velocity of the updraft in the openings 8 to 8" can be increased or decreased by the amount of adjustment. From the relationship of equations (]) and (2), if the flow velocity increases, the drop m decreases and the retention amount increases, and -. If the amount decreases, the amount of falling will increase and the amount of retention will decrease.

In either case, the amount of retention and amount of falling correspond to the flow velocity, which is balanced.

As shown in this embodiment, even if the gas amount is constant, the amount of retention can be arbitrarily adjusted within a certain range.
It is easy to change the reaction temperature, time, and atmosphere conditions within the device. In addition, the opening ratio (opening area per cross-sectional area of the cylindrical vessel at the opening) of the opening (8 to 8") in this invention is set so that very good flow and jet conditions can be obtained with the desired retention amount. This varies depending on the size of the particles and the amount of gas, and according to experiments using powder raw materials with a particle size of 0.6 to 1.7 m/m, a range of 15 to 30% is preferable.

(I3) Since the particles are blown up at the peripheral wall openings, instead of being blown up over the entire cross section by the openings of the perforated plate as in the past, the spouted bed is formed in a donut shape, and the upper layer is in a fluidized bed state. As a result, the particles as a whole are agitated by the descending jet, but in the fluidized bed far from the opening and in the vicinity of the bottom plate 6 of the fluidized bed, the agitation state is insufficient and the amount of particles stagnant becomes dense. Become.

Therefore, when firing sinterable powder or granular materials,
- a fluidized bed (
If it is necessary to heat and sinter at a temperature close to the sintering temperature (fusion temperature) of the powder or granular material, the particles may fuse with each other, causing the wall of the applicator (tube) to shaped vessel,
It may form a large fused mass and adhere to the bottom plate of the fluidized bed. In such a state, the granular material cannot be fired.

Therefore, in the present invention, a cylindrical jet chamber 9 is provided below the opening at the lowest stage. In the empty jet chamber 9, it is necessary to form a spouted bed that is vigorously stirred in order to prevent the phenomenon of fusion of powder and granular materials such as "double series".

For this purpose, it is preferable to narrow the cross-sectional area of the jet chamber cavity and to create a relatively high-speed airflow so that the flow velocity of the rising airflow is in the range of 0.4 to 1.0 times the terminal velocity of the particles.

Further, it is desirable that the position of the discharge 1''3 of the powder and granular material be located through the joint between the hollow jet chamber 9 and the air flow inlet 4 provided directly below it. When sintering materials are fired using the double cylindrical spouted bed at the highest temperature, the fired powder is not deposited near the outlet to prevent fusion and is removed from the equipment. Need to be released, drained and cooled.

Furthermore, in order to maintain the maximum temperature mentioned in Section 2, it is necessary to prevent the intake of cold outside air from the exhaust port 3 and the blowing out of the internal high-temperature air current. To do this, it is necessary to maintain the static pressure inside the device near the junction of the two series near atmospheric pressure. In order to maintain this static pressure, discharge the fired product normally, and form a spouted layer, it is necessary to make the discharge port 3 the above-mentioned joint.
] Two essential conditions.

The amount of powder and granules that stays in this hollow jet chamber 9 while forming a spouted layer increases due to the powder and granules that continuously fall from the opening 8.
Since the balance of 1) is disrupted, the amount is continuously discharged from i-1 discharge (]3, so the balance is always maintained at a constant level.

Next, in this invention, as shown in FIG. 9 are directly connected to each other, it is possible to vary the retention amount (time) of the granular material in each stage of the multi-stage fluidized bed and spouted bed.

With such a multi-stage system, different purposes such as preheating (heat recovery), continuous firing, firing, and cooling can be performed at each stage using a single device, which improves thermal efficiency and reaction rate.

Moreover, if the cylindrical vessel 1 of the multi-stage spouted bed apparatus is shaped so that its cross-sectional area differs in the vertical direction as shown in FIG.
Since the flow velocity of the airflow in each cross section can be varied, it is possible to reduce the rate at which fine powder particles are carried along with the airflow from the discharge port 5, for example.

The portion of the cylindrical jet chamber is not limited to being perpendicular, but may also have an inverted conical shape.

Next, in the multi-stage spouted bed apparatus of the present invention, the supply ports for powder and granules are provided in multiple stages as necessary, so that powder and granules such as powder raw materials, oxidizing agents, reducing agents, solid fuel, etc. are supplied to each stage. It is also possible to supply them separately and perform various reaction treatments. Similarly, the airflow inlet is also the airflow inlet 4 to 4'' shown in Figure 1.
In addition, in a multistage system, air, gaseous fuel, redox gas, burner, etc. can be introduced separately at each stage. Naturally, it is necessary that the powder supply port be provided above any opening, and that the air flow introduction port be provided below any one of the openings. Moreover, although the shape of the cylindrical vessel of the multistage spouted bed device in this invention has mainly been described as a cylindrical shape, a rectangular cylindrical shape can also be used. If the bottom plate of the fluidized bed is formed into a conical or pyramidal shape in accordance with the shape of the above-mentioned cylindrical vessel, it can be made to conform to the formation of the above-mentioned doughnut-shaped surrounding wall spouted bed.

From the above, the following effects of this invention can be obtained.

(1) A cylindrical jet chamber is provided, which can be operated as the highest temperature zone, and can be immediately released and discharged outside the device after firing, making the firing process of sinterable materials easier and lighter. In the case of fine-grained materials, foam sintering is also possible.

(2) When the apparatus according to the present invention is used for firing powder and granules, heat is transferred from the rising air to the powder and granules as the stages are stacked, and heat can be recovered up to the desired temperature, so thermal efficiency is greatly improved. will be improved.

(3) When used as a reactor, the amount of retention in each stage can be selected arbitrarily, so the reaction temperature can be adjusted even during operation of the device.
Easy to control reaction time. Furthermore, the gas atmosphere can be controlled by using a reducing agent or an oxidizing agent as necessary. Furthermore, since the reaction rate can be increased by multi-staged countercurrent flow, the size of the apparatus can be reduced.

(4) When using the hollow jet chamber as a cooler (2)
Due to the opposite effect, heat exchange from the powder to the air stream is performed efficiently.

(5) Compared to conventional fluidized bed devices, the aperture ratio is larger and the peripheral wall has a large number of openings, so there is no risk of clogging as seen in perforated plate systems. Moreover, the pressure loss at the opening is also reduced.

(6) Since the opening area can be changed from the outside during operation,
Even if the particle size of the supplied particles changes or the particle size decreases due to reaction, appropriate flow conditions (gas landscape, flow rate) can be created to correspond to the change in particle size.

(7) According to the device of this invention, by being divided into multiple stages in the height direction, a good jet flow condition can always be created, so the problems of slagging and bubble generation, which are concerns with one stage, are improved to a large lJ. be done.

(8) Since a spouted bed can be formed at each stage, intense flow occurs, and all the particles at each stage come into contact with high-speed upward air currents when falling, so that the heat transfer rate and reaction rate are further increased.

(9) Adjustment of retention amount has a wide range of applications for increasing and decreasing processing capacity.

(10) By making the fluidized bed bottom plate of a metal material for low-temperature processing and of refractory material for high-temperature firing, it can be applied to a wide range of temperatures.

(11) Since a burner can be attached to any stage, temperature control at each stage is easy.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a multi-stage spouted bed device which is an embodiment of the present invention, FIG. 2 is a diagram showing a typical example of a fluidized bed device according to the prior art, and FIG. A partially enlarged view of the layer bottom plate 6, opening 8, and area adjustment device 7, FIG. 4 is A in FIG. 3.
-A' sectional view. l...Cylindrical vessel 2...Powder supply port 3...Powder discharge port 4...Air flow inlet 6~6''...Fluidized bed bottom plate 7...Opening area adjustment 8～8″...Aperture procedure amendment, Marshal, June 30, 1986

Claims (9)

[Claims] (1) In a device that forms a fluidized bed and a spouted bed of updraft and powder in a vertical cylindrical container, the peripheral wall and the bottom plate of the fluidized bed are connected along the inner peripheral wall of the cylindrical container. An opening with a variable area structure for blowing upward airflow is provided in between, a hollow cylindrical jet chamber is provided below the opening, and the hollow jet chamber is connected to an air flow inlet provided directly below it. A multi-stage spouted bed device using a peripheral wall spout type fluidized bed, characterized in that a powder discharge port is provided through the opening, and a powder supply port and an air flow discharge port are provided above the opening. (2) A multi-stage spouted bed device using a peripheral wall spouted fluidized bed according to claim 1, characterized in that a plurality of openings with a variable area structure are provided in the vertical direction within the cylindrical vessel. (3) A multi-stage jet flow using a peripheral wall jet type fluidized bed according to claim 1 or 2, characterized in that the cylindrical container has a shape whose cross-sectional area differs in the vertical direction of the cylindrical container. Layer device. (4) An area in which the area of the opening can be changed by inserting and removing an area adjustment member from the outside of the cylindrical vessel into the opening formed between the bottom plate of the fluidized bed and the inner peripheral wall of the cylindrical vessel. A multi-stage spouted bed device using a peripheral spouted fluidized bed according to claim 1 or 2, characterized in that it has a variable structure. (5) It has a variable area structure in which the area of the opening formed between the fluidized bed bottom plate and the inner circumferential wall of the inverted cone-shaped cylindrical vessel is changed by moving the fluidized bed bottom plate up and down. A multi-stage spouted bed device using a peripheral spouted fluidized bed according to claim 1 or 2, characterized in that: (6) Using the peripheral wall spouted fluidized bed according to one of claims 1 to 3, characterized in that a plurality of powder supply ports are provided in the vertical direction of the cylindrical container. Multistage spouted bed device. (7) A multi-stage spouted bed using a peripheral spouted fluidized bed according to one of claims 1 to 3, characterized in that the air flow inlet is provided in multiple stages in the vertical direction of the cylindrical container. Device. (8) Multi-stage using a peripheral wall spout type fluidized bed according to one of claims 1, 2, 3, 6, or 7, characterized in that the shape of the cylindrical vessel is cylindrical or prismatic. Spouted bed device. (9) A multi-stage spouted bed device using a peripheral spouted fluidized bed according to claim 1, wherein the fluidized bed bottom plate has a conical shape.