Nozzle assembly of cold hydrogenation fluidized bed reactor

Abstract

The utility model discloses a nozzle assembly of a cold hydrogenation fluidized bed reactor, which relates to the technical field of polycrystalline silicon cold hydrogenation and comprises a fluidized bed furnace barrel, a nozzle distributor, a nozzle seat and a nozzle. The nozzle distributor is assembled in the fluidized bed furnace barrel, a plurality of nozzle seat holes are formed in the nozzle distributor, the plurality of nozzle seats and the plurality of nozzles are arranged, the plurality of nozzle seats are assembled in the plurality of nozzle seat holes, the plurality of nozzles are assembled in the plurality of nozzle seats, and the plurality of nozzles are arranged on the nozzle distributor in a multi-circle concentric circle mode. The distances from the inner wall of the fluidized bed furnace barrel to the inner wall of the fluidized bed furnace barrel are completely consistent, so that a gas flow field in the cold hydrogenation fluidized bed reactor is uniformly distributed, and the primary conversion rate is favorably improved. The ratio of the length to the inner diameter of the expanding section of the nozzle is 5-9 times of the diameter, so that stable plug flow is formed by gas, and the nozzle is prevented from being eroded and abraded to fail; meanwhile, in the blowing-out stage, the silicon powder deposited in the diameter expanding section can be blown up, automatically unblocked and automatically blown to be unblocked.

Description

Technical Field

[0001] The utility model relates to the technical field of polysilicon cold hydrogenation, and more specifically to a nozzle assembly of a cold hydrogenation fluidized bed reactor. Background Art

[0002] At present, the domestic production of polysilicon mostly adopts the modified Siemens process. The by-product silicon tetrachloride in the production is converted into trichlorosilane by the "cold hydrogenation" process to achieve recycling. The cold hydrogenation fluidized bed reactor is the core equipment of the cold hydrogenation device, and the distributor of the reactor is the core internal part. The distributor structure with a nozzle is currently widely used. The function of the nozzle is to use the high-speed upward airflow to blow the silicon powder falling from the cold hydrogenation fluidized bed reactor upward, so that the material forms a fluidized state.

[0003] The common structure of the distributor nozzle is tubular straight-through type. The tubular straight-through type has a simple structure and is easy to maintain, but it has the following defects:

[0004] 1. The layout of the nozzle is unreasonable, there are obvious biased blowing and biased flow areas, the gas flow field is uneven, and the conversion rate can be further improved. The conventional nozzle layout adopts a matrix layout. Obviously, from the circular cylinder cross-section of the cold hydrogenation fluidized bed reactor, it can be found that there are discontinuous and uneven areas along the circumference of the cylinder. The distance from the center of the nozzle in these areas to the inner wall of the furnace is not equal, that is, there are obvious biased blowing and biased flow areas. This will lead to an uneven gas flow field above the nozzle and inside the cold hydrogenation fluidized bed reactor.

[0005] 2. The nozzles of the cold hydrogenation fluidized bed reactor previously used were prone to clogging. Every time the system was shut down, it had to be cleared manually in the closed and confined space inside the furnace while wearing a long-tube respirator. In addition, the clearing operation required the use of an electric drill and a steel chisel to drill through the nozzle hole. The workers worked in a harsh working environment, with great difficulty and long working time.

[0006] 3. Short service life and high maintenance cost. The machine needs to be stopped for inspection and nozzle replacement every 6 months. It must be replaced every 12 months. Otherwise, the airflow ejected from the worn nozzle will be refracted and blown sideways, and will no longer maintain a strict parallel relationship with the central axis of the cylinder of the cold hydrogenation fluidized bed reactor, which will cause the cylinder wall of the cold hydrogenation fluidized bed reactor to be scour, worn, leaked, and burned. Utility Model Content

[0007] In order to overcome the defects existing in the above-mentioned prior art, the purpose of the utility model is to provide a nozzle assembly for a cold hydrogenation fluidized bed reactor to solve the problems existing in the above-mentioned prior art such as unreasonable nozzle layout, easy clogging, short service life, high maintenance cost, etc.

[0008] In order to achieve the above objectives, the technical solution adopted by the utility model is:

[0009] A nozzle assembly for a cold hydrogenation fluidized bed reactor comprises a fluidized bed furnace barrel, a nozzle distributor, a nozzle seat and a nozzle;

[0010] The nozzle distributor is installed in the fluidized bed furnace drum, a plurality of nozzle seat holes are arranged in the nozzle distributor, the nozzle seat and the nozzle are both provided with a plurality of nozzle seats, a plurality of nozzle seats are installed in the plurality of nozzle seat holes, a plurality of nozzles are installed in the plurality of nozzle seats, and a plurality of nozzles are arranged in a plurality of concentric circles on the nozzle distributor;

[0011] A vertically penetrating nozzle hole is arranged in the nozzle, and the nozzle hole comprises a throat section at the bottom and an expanded diameter section at the top. The expanded diameter section is in the shape of a cylindrical hole, and the ratio of its length to its inner diameter is 5 to 9 times the diameter.

[0012] Preferably, among the nozzles arranged in multiple concentric circles, the distance from the center of the outermost circle of nozzles to the inner wall of the fluidized bed furnace is 280 mm to 320 mm.

[0013] Preferably, the nozzle is made of N10675 or Si3N4.

[0014] Preferably, the nozzle is threadedly assembled on the nozzle seat.

[0015] Preferably, the inner diameter of the expanded diameter section of the nozzle is 24 mm.

[0016] Preferably, the throat section comprises a lower straight throat section and an upper frustum-shaped throat section.

[0017] Preferably, the nozzle distributor has a concave structure.

[0018] Preferably, the inner wall of the fluidized bed furnace is provided with a distributor mounting member for mounting the nozzle distributor.

[0019] Preferably, an air inlet is provided at the bottom of the fluidized bed furnace.

[0020] Beneficial effects of the utility model:

[0021] The utility model provides a nozzle assembly for a cold hydrogenation fluidized bed reactor, in which a plurality of nozzles are arranged in multiple concentric circles on a nozzle distributor, and the distances from any nozzle in the same circle to the inner wall of the fluidized bed furnace are completely consistent, so that the gas flow field inside the cold hydrogenation fluidized bed reactor is evenly distributed, which is beneficial to improving the primary conversion rate.

[0022] The utility model provides a nozzle assembly for a cold hydrogenation fluidized bed reactor, wherein the ratio of the nozzle expansion section length to the inner diameter is 5 to 9 times the diameter, so that the gas forms a stable plug flow, and the nozzle is prevented from being washed away and worn out; at the same time, during the shutdown stage, silicon powder deposited in the expansion section can be blown up, and the nozzle can rely on the high-speed airflow of the throat section to clear blockage and blow through by itself.

[0023] The utility model provides a nozzle assembly for a cold hydrogenation fluidized bed reactor, wherein the nozzle is made of N10675 or Si3N4 and has the characteristics of high hardness, easy processing, wear resistance and long service life.

[0024] The nozzle assembly of the cold hydrogenation fluidized bed reactor provided by the utility model adopts special materials and a newly designed structural proportion to prevent nozzle clogging and nozzle wear, thereby extending the service life. The nozzle will no longer be clogged or worn; the work intensity of workers is reduced and the working time is shortened; the flow field distribution is more uniform, the fluidization state is optimized, and the reaction conversion rate is increased by at least 1%. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the nozzle assembly of the cold hydrogenation fluidized bed reactor of the utility model;

[0026] Figure 2 This is a schematic diagram of the utility model in which a plurality of nozzles are arranged in multiple concentric circles on a nozzle distributor;

[0027] Figure 3 This is a schematic diagram of the nozzle of the utility model;

[0028] Reference numerals:

[0029] 1. fluidized bed furnace drum; 2. nozzle distributor; 3. nozzle seat; 4. nozzle; 41. throat section; 42. expansion section; 5. distributor mounting part. DETAILED DESCRIPTION

[0030] The concept, specific structure and technical effects of the present invention will be clearly and completely described below in combination with the embodiments and drawings to fully understand the purpose, features and effects of the present invention.

[0031] Example 1

[0032] A nozzle assembly for a cold hydrogenation fluidized bed reactor, such as Figure 1-Figure 3 As shown, it includes a fluidized bed furnace drum 1, a nozzle distributor 2, a nozzle holder 3 and a nozzle 4;

[0033] The nozzle distributor 2 is mounted in the fluidized bed furnace 1, and a plurality of nozzle seat holes are arranged in the nozzle distributor 2. The nozzle seats 3 and nozzles 4 are both provided with a plurality of nozzle seats 3 mounted in the plurality of nozzle seat holes, and a plurality of nozzles 4 mounted in the plurality of nozzle seats 3. The plurality of nozzles 4 are arranged in a plurality of concentric circles on the nozzle distributor 2;

[0034] The nozzle 4 is provided with a vertically penetrating nozzle hole, which includes a throat section 41 at the bottom and an expanded diameter section 42 at the top. The expanded diameter section 42 is a cylindrical hole, and the ratio of its length to the inner diameter is 5 to 9 times the diameter.

[0035] In this embodiment, the layout of the nozzles inside the cold hydrogenation fluidized bed reactor abandons the square matrix layout, and a plurality of nozzles 4 are arranged in multiple concentric circles on the nozzle distributor 2. From the cross section of the circular fluidized bed furnace 1 of the cold hydrogenation fluidized bed reactor, it can be found that the distance from any nozzle 4 in the same circle to the inner wall of the fluidized bed furnace 1 is completely consistent. This makes the gas flow field inside the cold hydrogenation fluidized bed reactor evenly distributed, which is conducive to improving the "primary conversion rate".

[0036] The nozzle is in the fluidized bed, and the central axis of the nozzle is strictly parallel to the central axis of the cylinder of the cold hydrogenation fluidized bed reactor, and is placed vertically. The airflow passes through the small hole of the throat and enters the expansion section at a high speed. If the expansion section is too short, the raw gas flow cannot form a plug flow in the expansion section, but a turbulent flow state, which will inevitably wear the expansion section of the nozzle and the nozzle seat on the periphery, and eventually cause the nozzle to be washed and worn out in a short time. If the expansion section is too long, once the system stops, the silicon powder falls into the expansion section. Due to the deposition of its own weight, the silicon powder exerts pressure on the inner wall of the side of the expansion section, which will increase the friction between the silicon powder and the inner wall of the expansion section, generate a dense silicon powder column, and form a self-locking in the expansion section. Finally, when the system resumes production, the airflow passes through the small hole of the throat. Even if it forms a high speed, it cannot blow through this self-locking dense silicon powder column.

[0037] In the nozzle 4 of this embodiment, after the airflow flows through the throat, the expansion section is used as the basic condition for forming a plug flow. Through mathematical modeling and simulation calculation, it is found that a minimum length of 5 times the diameter (with the inner diameter of the expansion section as the base) is required to form a stable plug flow. At the same time, it has been verified that when the expansion section reaches a length of 10 times the diameter, or a longer length, the silicon powder in the expansion section will not be blown up, and the nozzle cannot rely on the high-speed airflow of the throat to clear the blockage and blow through by itself. Therefore, in the end, the design core of the nozzle of this embodiment is "the ratio of the length of the expansion section to the inner diameter of the expansion section is in the range of 5 times the diameter to 9 times the diameter".

[0038] Example 2

[0039] This embodiment further elaborates on the basis of embodiment 1. In the multiple concentric circles of the nozzles 4, the distance from the center of the outermost circle of the nozzles 4 to the inner wall of the fluidized bed furnace 1 is 280 mm to 320 mm. For a single cold hydrogenation fluidized bed reactor, the number of nozzles arranged depends on the operating volume flow rate of the single equipment during operation. The gas flow rate of a single nozzle throat section is 65 m / s to 85 m / s on average according to the number of nozzles.

[0040] The material of the nozzle 4 is N10675 or Si3N4. After testing, the nozzles made of these two materials have the characteristics of high hardness, easy processing, wear resistance and long service life.

[0041] The nozzle 4 is threadedly assembled on the nozzle seat 3, and the nozzle 4 is easy to install and remove.

[0042] The inner diameter of the expanded diameter section 42 of the nozzle 4 is 24 mm. The throat section 41 includes a straight throat section at the bottom and a frustum-shaped throat section at the top.

[0043] The nozzle distributor 2 is of a concave structure. The inner wall of the fluidized bed furnace drum 1 is provided with a distributor mounting member 5 for mounting the nozzle distributor 2 .

[0044] The bottom of the fluidized bed furnace drum 1 is provided with an air inlet.

[0045] The gas enters the cold hydrogenation fluidized bed reactor through the gas inlet, flows upward, and then upward through the nozzle 4. In the nozzle 4, the gas flows through the throat section 41 and enters the expansion section 42 at a high speed. The gas forms a plug flow in the expansion section 42, blowing the silicon powder above.

[0046] The system is shut down, and silicon powder falls into the expanded diameter section 42. When the system is resumed, the airflow passes through the throat section 41, driving the silicon powder in the expanded diameter section 42 to flow upward at a high speed, clearing the blockage and blowing through by itself.

[0047] The implementation methods of the present invention are described in detail above, but the present invention is not limited to the described embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention, and these equivalents or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A nozzle assembly for a cold hydrogenation fluidized bed reactor, characterized in that: It comprises a fluidized bed furnace drum (1), a nozzle distributor (2), a nozzle seat (3) and a nozzle (4); The nozzle distributor (2) is mounted in the fluidized bed furnace drum (1), a plurality of nozzle seat holes are provided in the nozzle distributor (2), the nozzle seats (3) and the nozzles (4) are both provided with a plurality of nozzle seats (3) mounted in the plurality of nozzle seat holes, a plurality of nozzles (4) mounted in the plurality of nozzle seats (3), and the plurality of nozzles (4) are arranged in a plurality of concentric circles on the nozzle distributor (2); The nozzle (4) is provided with a vertically penetrating nozzle hole, the nozzle hole comprising a throat section (41) at the bottom and an expanded diameter section (42) at the top, the expanded diameter section (42) being in the shape of a cylindrical hole, the ratio of its length to its inner diameter being 5 to 9 times the diameter.

2. The nozzle assembly of the cold hydrogenation fluidized bed reactor according to claim 1, characterized in that: Among the nozzles (4) arranged in multiple concentric circles, the distance from the center of the nozzles (4) in the outermost circle to the inner wall of the fluidized bed furnace tube (1) is 280 mm to 320 mm.

3. The nozzle assembly of the cold hydrogenation fluidized bed reactor according to claim 1, characterized in that: The material of the nozzle (4) is N10675 or Si3N4.

4. The nozzle assembly of the cold hydrogenation fluidized bed reactor according to claim 1, characterized in that: The nozzle (4) is threadedly assembled on the nozzle seat (3).

5. The nozzle assembly of the cold hydrogenation fluidized bed reactor according to claim 1, characterized in that: The inner diameter of the expanded diameter section (42) of the nozzle (4) is 24 mm.

6. The nozzle assembly of the cold hydrogenation fluidized bed reactor according to claim 1, characterized in that: The throat section (41) comprises a lower straight throat section and an upper frustum-shaped throat section.

7. The nozzle assembly of the cold hydrogenation fluidized bed reactor according to claim 1, characterized in that: The nozzle distributor (2) has a concave structure.

8. The nozzle assembly of the cold hydrogenation fluidized bed reactor according to claim 1, characterized in that: The inner wall of the fluidized bed furnace drum (1) is provided with a distributor mounting member (5) for mounting the nozzle distributor (2).

9. The nozzle assembly of the cold hydrogenation fluidized bed reactor according to claim 1, characterized in that: An air inlet is arranged at the bottom of the fluidized bed furnace drum (1).

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