CN1331587C - Circular spout bed equipped with circular multi-nozzle ventilation mechanism - Google Patents

Abstract

The present invention relates to an annular spouted bed allocated with annular a circular of nozzles and a V-shaped diversion chamber. Two concentric vertical cylinders which use a rotating shaft as a center form annular space, a wind-distribution mechanism with a plurality of nozzles is arranged at the bottom of the annular space, a transition circular cone arranged on the lower part of an inner cylinder is connected with a discharge pipe, a rotating tapered distributor is arranged on the upper end of the inner cylinder, the rotating tapered distributor is connected with a motor of the upper end through the center shaft, and a pressure-stabilizing wind chamber is arranged on the lower part of the wind-distribution mechanism. Materials enter the tapered distributor through a feeding pipe, pressurized fluid enters the wind-distribution mechanism through the pressure-stabilizing wind chamber to be ejected into the annular space, an auger stripper is arranged at the bottom of the inner cylinder, and stirring blades are arranged on the rotating shaft. The present invention has the advantages of compact structure and wide fluidized operation flexibility range, a higher partition wall heat-transfer effect can be obtained, the rates of gas-solid heat exchange and granule mixing are improved, the binding of granules on wall surfaces can be effectively prevented, and the multi-nozzle wind-distribution mechanism allocated by the combination of the peculiar nozzles and the V-shaped diversion chamber effectively reduces pressure loss and improves efficiency.

Description

Annular spouted bed equipped with annular multi-nozzle air distribution mechanism

technical field

The invention relates to an annular spouted bed equipped with a circular multi-nozzle air distribution mechanism, which is a highly efficient gas-solid contact reactor, and belongs to material drying, biomass gasification, activated carbon production, coal gasification co-production and coal smoke Gas desulfurization and other technical fields.

Background technique

Spouted bed technology is an important branch of fluidization technology, which first appeared in the early 1950s. Spouted bed technology is mainly used for grain drying, granulation, particle coating, etc. In addition, the spouted bed also plays an important role in low-quality coal combustion and gasification, low calorific value industrial waste combustion, and hydrogen production by partial oxidation of natural gas.

The traditional spouted bed structure is mainly composed of three parts: the spouted gas inlet nozzle, the bottom inverted cone and the cylindrical main body. Fluid (usually gas) is injected vertically upward through a small hole (nozzle or orifice) located at the center of the conical bottom, forming a jet area that gradually extends upward as the fluid velocity increases. When the fluid injection rate is high enough, the jet zone will penetrate the bed to create a dilute phase gas-solid slug (spray zone) within the particle bed that moves rapidly upward through the center of the bed. When these particles entrained by the fluid jet and moving upward at high speed pass through the particle bed (annulus) that moves slowly downward around it and rise to a certain height above the surface of the bed, due to the sudden decrease in fluid velocity, The particles will fall back to the surface of the annulus area by gravity like a fountain to form a fountain area. These falling particles slowly move down along the annulus to the lower part of the bed, and then infiltrate into the injection zone to be re-entrained to form a very regular internal circulation of particles. This kind of flow phenomenon with dilute-phase injection area, dense-phase annulus area and fountain area three-area flow structure is eruption phenomenon.

The structure of the spouted bed has a great influence on the occurrence of the spouting phenomenon. For example, when the ratio of the diameter of the inlet nozzle to the diameter of the spouted bed cylinder is greater than a certain critical value, there will be no spraying of particles, and the bed will directly change from a fixed bed to a polyfluidized state as the flow rate increases. .

The traditional fluidized bed is prone to stratification and throttling during operation, which is unfavorable to the heat and mass transfer between fluid and particles. However, the single spouted bed often has a dead zone at the bottom of the annulus area and agglomeration of easily bonded particles in the annulus area, which affects particle mixing, gas-solid heat transfer, and normal operation.

In order to overcome the influence of the "dead zone" at the bottom of the spouted bed annular zone, an auxiliary gas can be introduced at the bottom of the annular zone to loosen the particle bed at the bottom of the annular zone and weaken or basically eliminate the "dead zone". If the annular zone forms a moving bed state, it is called an aerated spouted bed. If the annular zone forms a fluidized state, it is a spouted fluidized bed (spouted bed). Whether it is an inflatable spouted bed or a spouted bed, the center of the bed body is a nozzle area, also known as a dilute-phase conveying area, and its surrounding area is an annular area, also known as a dense-phase area. The air supply in the annular area and the air supply in the central spray area need to be within a certain ratio range to achieve a good working condition.

In the existing multi-nozzle spouted bed, a plurality of parallel incident nozzles are arranged at the bottom of the spouted bed, and the flow through each inlet nozzle must be controlled separately, and the conical sections connected with each other are used, which is easy to cause air supply in the bed Inhomogeneity, especially when the air volume is small, dead zones are prone to occur in local areas. The air volume of multiple air supply pipes is difficult to control separately, and the actual operation is very difficult.

Contents of the invention

The object of the present invention is to address the above-mentioned shortcomings of the existing spouted bed and fluidized bed, and provide an annular spouted bed equipped with a circular multi-nozzle air distribution mechanism, which has a compact structure, fast bed heat transfer and partition wall heat transfer rate, It can effectively prevent the dead zone at the bottom of the annulus area that often occurs in a single spouted bed and the agglomeration of some easily bonded particles in the annulus area, strengthen the disturbance of the gas flow to the bed, increase the particle mixing rate and the residence period of the gas flow in the bed .

In order to achieve this purpose, the annular space of the annular spouted bed of the present invention is composed of two concentric vertical cylinders inside and outside, and a unique multi-nozzle air distribution mechanism is arranged at the bottom of the annular space, consisting of multiple independent eight-type nozzles or oblique nozzles and The corresponding V-shaped diversion chamber is formed. The lower part of the inner cylinder is equipped with a transition cone to connect with the discharge pipe, the rotary cone distributor installed at the upper end of the inner cylinder is connected to the motor at the upper end through the central rotating shaft, and the feed pipe connected to the top feeder is located in the rotary cone distributor. the top of the device. The lower part of the air distribution mechanism is a pressure-stabilizing air chamber. The pressurized fluid enters the air distribution mechanism through the pressure-stabilizing air chamber and is sprayed into the annular space. The air volume and air pressure of each nozzle are controlled separately. A screw unloader is arranged at the bottom of the inner cylinder, and a stirring blade is arranged on the rotating shaft. The material in the feeder enters the cone distributor through the feeding pipe, and the material is evenly thrown into the annular space under the action of centrifugal force. The material is uniformly sprayed and fluidized in the annular space, the large particles are sprayed and fluidized in the bottom dense phase area, and the fine particles in the upper dilute phase area enter the inner cylinder through the overflow port at the upper end of the inner cylinder. The material stored in the inner cylinder is stirred by the stirring blade, and is discharged from the discharge pipe under the push of the screw unloader.

Concrete structure of the present invention is as follows:

An annular spouted bed equipped with a circular multi-nozzle air distribution mechanism is mainly composed of an annular space, a unique multi-nozzle air distribution mechanism, a rotating cone distributor, a pressure-stabilizing air chamber, and a spiral discharge blade. The outer cylinder and the inner cylinder are two concentric vertical cylinders with the rotating shaft as the center, the diameter of the inner cylinder is 100-2000mm, and the diameter of the outer cylinder is 200-2800mm. The lower part of the inner cylinder is equipped with a transition cone to connect with the discharge pipe, and the bottom of the annular space formed by the outer cylinder and the inner cylinder is equipped with a unique multi-nozzle air distribution mechanism, which consists of 4 to 100 eight-type nozzles and corresponding nozzles and corresponding nozzles. The V-shaped guide chamber is composed of the nozzle size d is 5-300mm, the angles α and β between the V-shaped guide plate and the horizontal line are 50°-90°, the angle _θ1 between the nozzle and the horizontal line is 20°-90°, θ ₂ ranges from 20° to 160°. In the upper space of the spouted bed, that is, above the overflow port at the upper end of the inner cylinder, there is a rotary cone distributor. The feed pipe connected to the top feeder is located above the rotary cone distributor, and the material enters through the feed pipe. Cone dispenser. The rotating cone distributor is connected with the motor at the upper end through the rotating shaft in the center, and throws the material evenly into the annular space under the action of centrifugal force. The pressure-stabilizing air chamber set at the lower part of the air distribution mechanism is consistent with the diameter of the outer cylinder. The pressurized fluid provided by the blower or external air source is introduced into the pressure-stabilizing air chamber through the air supply pipe, and then enters the air distribution mechanism and is sprayed into the annular space. The material is evenly sprayed and fluidized by the airflow in the annular space and undergoes gas-solid contact reaction. The large particles are sprayed and fluidized in the dense phase area at the bottom, and the fine particles are entrained by the airflow into the upper dilute phase area, and some particles pass through the overflow at the upper end of the inner cylinder. The gas outlet enters the inner cylinder, and the airflow is discharged from the gas outlet. A screw unloader is installed at the bottom of the inner cylinder. The screw unloader and the rotary cone distributor work on the same rotating shaft, and a stirring blade is set on the rotating shaft. The materials stored in the inner cylinder are stirred by the stirring blade, and Under the push of the screw unloader, it is unloaded from the discharge pipe.

Jet fluidization principle of the present invention is:

The pressurized gas enters the air distribution mechanism through the pressure-stabilizing air chamber and is sprayed into the annular space. The air distribution mechanism is composed of multiple nozzles and a V-shaped diversion chamber, and the material is sprayed and fluidized in the annular space. When the amount of material in the annular spouted bed is very small, the particles are basically thrown out of the V-shaped diversion chamber by spouting, and move in the bed in an annular oscillation cycle. With the further increase of the loading amount in the bed, the oscillation height decreases. After reaching a certain loading amount, the granular materials sprayed at the tuyeres begin to accumulate and fill. Further increasing the loading capacity in the bed, the particle storage and air supply of each tuyere gradually become uniform, and the particles appear partitioned spouting fluidization in the annular spouted bed, which is divided into three distinct zones along the bed height direction. Spray fluidization area: (1) The flow area in the V-shaped diversion chamber is dominated by particle filling movement and jet agitation; (2) The dense-phase jet fluidization region in the upper part of the V-shaped diversion chamber; (3) The upper part Particle dilute phase entrainment zone in space.

In the V-shaped diversion chamber near the tuyere, the air supply pushes the particles to spray and stir in the V-shaped diversion chamber or spray out of the V-shaped diversion chamber. In the V-shaped deflector chamber, the particles are basically based on filling movement and jet stirring to form the upper and lower circulation and mixing of materials; due to the accumulation of particles, within a certain thickness range close to the wall of the inclined guide plate, the particles move in the form of movement , thus resulting in the rapid exchange of materials in the adjacent V-shaped guide chambers in the ring direction through the inclined guide plates.

In the particle dense-phase movement area above the V-shaped diversion chamber, due to the continuous rise of the air cavity, this part of the particle layer is mainly in the form of jet fluidization, and the particles on the surface of the dense-phase layer spray and fluctuate within a certain height. With the increase of material loading, the height of the dense phase zone increases continuously, and the jet fluidization movement of particles becomes more intense. With the increase of particle loading in the bed, the height of the particle dense phase region increases continuously. Under the same particle loading and jet air volume, the height of the spouted bed decreases with the increase of particle size.

In the annular spouted bed, when the spraying height of the particles exceeds the overflow port set on the inner cylinder, some particles enter the inner cylinder through the overflow port; a screw unloader is set at the bottom of the inner cylinder, and the screw discharge The feeder and the distributor work on the same rotating shaft, and a stirring blade is set on the rotating shaft. The material stored in the inner cylinder is stirred by the stirring blade, and is discharged from the discharge pipe under the push of the screw unloader.

The present invention has the following advantages:

1. The annular spouted bed has a compact structure and can obtain a high heat transfer effect between partition walls.

2. The fluidization of materials in the annular spouted bed requires less gas consumption and low energy consumption, and can form a denser bed in a wide range, and the fluidization operation has a wide elastic range.

3. The gas-solid heat transfer rate of the annular spouted bed is fast, the particle mixing is intense and uniform, and the bed material is greatly disturbed, which can effectively prevent the material from sticking and clogging, and the temperature distribution is uniform.

4. Adopt a novel and unique air distribution mechanism, multiple independent nozzles are equipped with independent V-shaped diversion chambers, with small pressure loss and high efficiency;

5. Due to the use of an effective pressure-stabilizing air chamber, the air volume entering each nozzle on the air distribution mechanism is uniform and stable, and there is no need to separately control the air volume and air pressure of each nozzle.

6. The oblique nozzle air distribution mechanism is used to make the air flow spiral up around the inner cylinder in the annular space, prolong the residence time of the gas in the bed, and strengthen the gas-solid heat exchange and particle mixing rate. At the same time, the transmission rate of granular materials along the ring direction is correspondingly accelerated. Due to the strong swirling and turbulence of the airflow, the adhesion of particles on the wall can be effectively prevented.

7. Novel material distribution and discharge system, unique mixing and discharge technology can effectively prevent materials from sticking and ensure smooth discharge.

Description of drawings

Fig. 1 is a schematic structural view of the annular spouted bed of the present invention.

In Figure 1, 1 is the feeder, 2 is the motor, 3 is the gas outlet, 4 is the rotating cone distributor, 5 is the rotating shaft, 6 is the outer cylinder, 7 is the inner cylinder, 8 is the spiral discharge blade , 9 is the air distribution mechanism, 10 is the discharge pipe, 11 is the air supply pipe, 12 is the blower, 13 is the pressure-stabilizing air chamber, 14 is the transition cone, 15 is the stirring blade, 16 is the annular space, 17 is the feed Tube.

Figure 2 is a schematic diagram of a multi-nozzle air distribution mechanism with a combination of oblique nozzle air supply and V-shaped diversion chamber.

In Fig. 2, 18 is a V-shaped deflector, 19 is an oblique nozzle, 20 is a spout, 21 is a sealing bottom plate, 22 is a V-shaped deflector chamber, and d is the width of the spout.

Fig. 3 is a schematic diagram of a multi-nozzle air distribution mechanism configured with eight-type nozzle air supply and a V-type diversion chamber.

In Fig. 3, 18 is a V-shaped deflector, 20 is a spout, 21 is a sealed bottom plate, 22 is a V-shaped deflector chamber, 23 is an eight-type nozzle, and d is the width of the spout.

Fig. 4 is the air distribution mechanism embodiment 1 (top view) of eight spouts.

In Fig. 4, 7 is an inner cylinder, 6 is an outer cylinder, 20 is a spout, and eight spouts are arranged along the ring direction.

Fig. 5 is the air distribution mechanism embodiment 2 (top view) of eight spouts.

In Fig. 5, 7 is an inner cylinder, 6 is an outer cylinder, 20 is a spout, eight spouts are arranged along the ring, 24 is an inner cone deflector, and 25 is an outer cone deflector.

Fig. 6 is a B-B sectional view in Fig. 5 .

In Fig. 6, 20 is a nozzle, eight nozzles are arranged along the ring direction, 21 is an annular sealing bottom plate, 22 is a V-shaped diversion chamber, 23 is an eight-shaped nozzle, 24 is an inner cone deflector, and 25 is an outer cone body guide plate, 26 is the inner cone of the nozzle guide, and 27 is the outer cone of the nozzle guide.

Detailed ways

The technical solution of the present invention will be further described below in conjunction with the accompanying drawings.

The annular spouted bed structure of the present invention is shown in Figure 1, mainly by annular space 16, air distribution mechanism 9, rotating cone distributor 4, stabilizing air chamber 13, screw unloader 8, feeder 1, outlet Material pipe 10 etc. are formed. The outer cylinder 6 and the inner cylinder 7 are two concentric vertical cylinders with the rotating shaft 5 as the center. The diameter of the outer cylinder 6 is 200-2800mm, and the diameter of the inner cylinder 7 is 100-2000mm. A transition cone 14 is arranged at the bottom of the inner cylinder 7 , and the bottom of the transition cone 14 is connected with the discharge pipe 10 . The outer cylinder 6 and the inner cylinder 7 form an annular space 16, and a unique multi-spout air distribution mechanism 9 is arranged at the bottom of the annular space 16, and a rotating cone distributor 4 is arranged above the overflow port at the upper end of the inner cylinder 7 , the feed pipe 17 connected to the top feeder 1 is located above the rotary cone distributor 4, the material enters the rotary cone distributor 4 through the feed pipe 17, and the rotary cone distributor 4 passes through the central rotating shaft 5 and the upper end The motor 2 is connected, and the motor 2 drives the rotating cone distributor 4 to rotate through the rotating shaft 5, so that the materials in the rotating cone distributor 4 are evenly thrown into the annular space 16 under the action of centrifugal force. The lower part of the air distribution mechanism 9 is a cylindrically-shaped stabilizing air chamber 13 , and the diameter of the stabilizing air chamber 13 is consistent with that of the outer cylinder 6 of the annular space 16 . The pressurized fluid is provided by the blower 12 or an external air source, and is introduced into the pressure-stabilizing air chamber 13 through the air-supply pipe 11. The airflow in the air-stabilizing air chamber 13 enters the air distribution mechanism 9 and is sprayed into the annular space 16, and the material is in the annular space 16. Evenly sprayed and fluidized and gas-solid contact reaction occurs, part of the particles enter the interior of the inner cylinder 7 through the overflow port at the upper end of the inner cylinder 7; The rotating cone distributor 4 uses the same rotating shaft 5 to work, and the rotating shaft 5 is provided with a stirring blade 15 inside the inner cylinder 7, and the material stored in the inner cylinder 7 is stirred by the stirring blade 15, and is discharged in the spiral discharge. Under the promotion of the feeder 8, it is discharged from the discharge pipe 10.

The air distribution mechanism of the present invention adopts a multi-spout structure, and the spouts can adopt oblique nozzles or eight-type oblique nozzles. Figure 2 shows one of the technical solutions of the multi-nozzle air distribution mechanism of the present invention. The multi-nozzle air distribution mechanism designed in this scheme is a combination of inclined nozzle air supply and V-shaped diversion chamber, which is mainly composed of oblique nozzle 19, V-shaped diversion chamber 22, nozzle 20, and sealing bottom plate 21. The sealing bottom plate 21 is provided with a plurality of spouts 20 along the ring direction, and an oblique nozzle 19 is arranged below each spout 20, and each spout 20 and two deflectors 18 arranged above constitute an independent V-shaped deflector chamber 22, and the oblique nozzle 19 Corresponding to the V-shaped diversion chamber 22 one by one, the number is the same. The airflow of the pressure-stabilizing air chamber 13 is sprayed into the V-shaped guide chamber 22 from the nozzle 20 through the oblique nozzle 19 . The spout width d=5～300mm of spout 20, the included angle α, β=40°～90° between two guide plates 18 and sealing base plate 21, the angle between two sides of oblique nozzle 19 and sealing base plate 21 The included angle θ ₁ =20°-90°, θ ₂ =20°-160°.

Fig. 3 shows the second technical solution of the multi-nozzle air distribution mechanism of the present invention. The multi-nozzle air distribution mechanism designed in this scheme is a combination of eight-type nozzle air supply and V-type diversion chamber, mainly composed of eight-type nozzles 23, V-type diversion chamber 22, nozzles 20, and sealing bottom plate 21. On the annular sealing bottom plate 21, a plurality of spouts 20 are arranged in the circumferential direction, and eight-shaped nozzles 23 are arranged below each spout 20, and each spout 20 and two deflectors 18 arranged above constitute an independent V-shaped deflector chamber 22 , the eight-shaped nozzles 23 correspond to the V-shaped guide chambers 22 one-to-one, and the numbers are consistent. The airflow of the pressure-stabilizing air chamber 13 is sprayed into the V-shaped guide chamber 22 from the nozzle 20 through the eight-shaped nozzle 23 . The spout width d=5～300mm of spout 20; The included angle α, β=40°～90° between two guide plates 18 and sealing bottom plate 21, between two sides of eight-type nozzle 23 and sealing bottom plate 21 The included angle θ ₁ =θ ₂ =20°～90°.

Fig. 4 is Embodiment 1 of the eight-spout air distribution mechanism of the present invention, and Fig. 4 is a top view of the air distribution mechanism. An air distribution mechanism is arranged at the bottom of the annular space formed by the outer cylinder 6 and the inner cylinder 7. Eight nozzles 20 are evenly arranged along the annular space. V-shaped chamber connection.

Fig. 5 is Embodiment 2 of the air distribution mechanism of eight nozzles of the present invention, the air distribution mechanism provided between the inner cylinder 7 and the outer cylinder 6 is also equipped with an inner cone deflector 24 and an outer cone deflector Eight nozzles 20 are uniformly arranged in the annular space between the plate 25 , the outer cone deflector 25 and the inner cone deflector 24 .

FIG. 6 is a sectional view of BB in FIG. 5 . As shown in Figure 6, the air distribution mechanism also includes an outer cone deflector 25 and an inner cone deflector 24 arranged on the annular sealing bottom plate 21, and an outer cone deflector 25 and an inner cone deflector 24 The annular space between is evenly divided into eight V-shaped deflector chambers 22, the angle Ψ ₁ between the outer cone deflector 25 and the outer cylinder 6 = 0 ~ 35°, the inner cone deflector 24 and the inner cylinder 6 The included angle Ψ ₂ of the cylinder 7 =0～35°; on the annular sealing bottom plate 21, eight spouts 20 are evenly arranged in the circumferential direction; under each spout 20, an independent eight-type nozzle 23 is correspondingly arranged, and on the top of each spout 20 Correspondingly, the V-shaped diversion chamber 22 is set, and the eight-type nozzle 23 is equipped with a nozzle diversion inner cone 26 and a nozzle diversion outer cone 27, and the included angle between the nozzle diversion inner cone 26 and the inner cylinder 7 is 0-35° °, the angle between the nozzle guide outer cone 27 and the outer cylinder 6 is 0-35°.

The nozzles 20 of the air distribution mechanism in the present invention are not limited to 8, and may be 4 to 100.

Claims (5)

1. An annular spouted bed equipped with a circular multi-nozzle air distribution mechanism, characterized in that the outer cylinder (6) and the inner cylinder (7) are two concentric vertical cylinders centered on the rotating shaft (5), The lower part of the inner cylinder (7) is provided with a transition cone (14) connected to the discharge pipe (10), and the bottom of the annular space (16) formed by the outer cylinder (6) and the inner cylinder (7) is provided with a multi-nozzle air distribution mechanism (9), the top of the upper overflow of the inner cylinder (7) is provided with a rotary cone distributor (4), and the feed pipe (17) connected to the top feeder (1) is located on the rotary cone distributor ( 4), the rotating cone distributor (4) is connected to the motor (2) at the upper end through the central rotating shaft (5), and the pressure-stabilizing air chamber (13) at the lower part of the air distribution mechanism (9) is connected to the outer cylinder (6 ) have the same diameter, the fluid provided by the air blower (12) or the external air source is introduced into the pressure-stabilizing air chamber (13) through the air supply pipe (11), and the screw unloader (8) arranged at the bottom of the inner cylinder (7) is connected with the rotating The cone distributor (4) uses the same rotating shaft (5) to work, and the rotating shaft (5) is provided with stirring blades (15); The combined configuration of the type diversion chamber is composed of oblique nozzles (19) or eight-type nozzles (23), V-type diversion chambers (22), nozzles (20), and sealing bottom plates (21). A plurality of spouts (20) are arranged in a circular direction, and oblique nozzles (19) or eight-type nozzles (23) are arranged below each spout (20), and each spout (20) and two deflectors (18) arranged above it constitute An independent V-shaped diversion chamber (22). 2. The annular spouted bed configured with a circular multi-nozzle air distribution mechanism according to claim 1, characterized in that the diameter of the outer cylinder (6) is 200-2800 mm, and the diameter of the inner cylinder (7) is 100-2800 mm. 2000mm. 3. The annular spouted bed configured with a circular multi-nozzle air distribution mechanism according to claim 1, characterized in that the nozzle width d of the nozzle (20) is 5-300mm, and the two deflectors (18) and the sealing bottom plate The included angles α, β=40°～90° between (21), the included angle θ ₁ between the two sides of the oblique nozzle (19) and the sealing bottom plate (21)=20°～90°, θ ₂ =20°-160°; the included angle between the two sides of the eight-type nozzle (23) and the sealing bottom plate (21) is θ ₁ =θ ₂ =20°-90°. 4. The annular spouted bed equipped with a circular multi-nozzle air distribution mechanism according to claim 1, characterized in that the multi-nozzle air distribution mechanism (9) also includes an outer cone guide set on the sealing bottom plate (21) The annular space between the plate (25) and the inner cone deflector (24), the outer cone deflector (25) and the inner cone deflector (24) is equally divided into V-shaped deflector chambers (22) , the angle ψ ₁ between the outer cone deflector (25) and the outer cylinder (6) = 0～35°, the angle ψ ₂ between the inner cone deflector (24) and the inner cylinder (7) = 0～35°. 5. The annular spouted bed equipped with a circular multi-nozzle air distribution mechanism according to claim 1, characterized in that there are 4 to 100 nozzles (20).

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