A circulating fluidized bed system for gasification fly ash treatment

Abstract

The utility model discloses a kind of for gasification fly ash treatment's circulating fluidized bed system, belong to solid waste treatment equipment technical field.The system includes hearth, primary air chamber, cyclone separator, leg, gas-solid heat exchange bed and tail flue.For solving the problem of high fine particle escape rate, fluidization is uneven, system is additionally provided with fine powder agglomeration module, heavy metal solidification module and activation reaction module.The fine powder agglomeration module includes built-in cyclone mixing chamber and the agglomerator of ultrasonic atomizer;The heavy metal solidification module includes the ammonia injection pipe in specific position below fly ash lance;The activation reaction module is connected with gas-solid heat exchange bed by flange pipeline, and its bottom is equipped with the gradient air distribution plate of three layers different aperture.The utility model improves by above structure, effectively increases fly ash particle size from physics, homogenizes fluidized bed, realizes sealed link between modules, significantly reduces fine particle escape rate, improves system operation stability and integration.

Description

Technical Field

[0001] This utility model relates to the technical field of solid waste treatment equipment, specifically to a circulating fluidized bed system, and more particularly to a circulating fluidized bed system for the resource utilization of gasified fly ash. Background Technology

[0002] Coal gasification and other processes generate a large amount of gasification fly ash, which has a fine particle size (median particle size D50 is usually less than 50 μm), high residual carbon content, and is rich in heavy metals, making it difficult to treat. Currently, circulating fluidized bed (CFB) technology is commonly used to incinerate it.

[0003] However, existing circulating fluidized bed (CFB) equipment has significant drawbacks in treating such fine fly ash: First, due to the extremely fine particle size, fly ash particles are easily entrained by the airflow during fluidization, escaping directly from the top of the furnace, resulting in a huge dust removal load, low processing efficiency, and severe dust pollution. Second, traditional fluidized bed air distribution plates are typically single-layered structures with uniform pore sizes. This structure makes it difficult to effectively distribute airflow evenly, easily causing fluidization unevenness phenomena such as "channeling" and "surges," further exacerbating the separation and escape of fine particles and affecting the stability of the temperature field inside the furnace. Third, existing equipment has a single function, typically only achieving incineration reduction and solidification of heavy metals, without forming an efficient and sealed structural coupling with subsequent resource extraction units, thus limiting its potential for resource utilization.

[0004] Therefore, there is an urgent need for a processing system with optimized structure to address the characteristics of fine particulate matter, thereby solving the problems of high fine particle escape rate, poor fluidization quality, and low system integration from the perspective of equipment construction. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing a circulating fluidized bed system for treating gasified fly ash. The purpose of this invention is to effectively reduce the escape rate of fine particulate matter from gasified fly ash during the treatment process, improve the stability of the fluidized bed, and achieve efficient and sealed connection between the treatment system and the resource recovery module by improving the system's physical structure.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A circulating fluidized bed system for treating gasified fly ash includes a furnace, a primary air chamber located at the bottom of the furnace, a cyclone separator connected to the top outlet of the furnace, a material leg connected to the bottom of the cyclone separator, and a gas-solid heat exchange bed and a tail flue connected to the gas outlet of the cyclone separator.

[0007] The improvement lies in that the system further includes: The fine powder agglomeration module includes a gasification fly ash spray gun located at the top of the furnace and an agglomerator connected to the gasification fly ash spray gun; the agglomerator is provided with a swirling mixing chamber and an ultrasonic atomizer inside, and the agglomerator is also connected to a feed nozzle for inputting binder. A heavy metal solidification module includes an ammonia injection pipe disposed on the side wall of the furnace, the ammonia injection pipe being located 1-2 meters below the gasification fly ash spray gun; The activation reaction module includes an activation reactor, which is connected to the solid particle outlet of the gas-solid heat exchange bed via a flanged pipe; the bottom of the activation reactor is provided with three layers of gradient air distribution plates, and a residual carbon combustion chamber is provided inside.

[0008] As a further improvement of this utility model, the three-layer gradient air distribution plate includes an upper air distribution plate, a middle air distribution plate, and a lower air distribution plate arranged from top to bottom; the aperture of the upper air distribution plate is 1.0±0.1mm, the aperture of the middle air distribution plate is 3.0±0.2mm, and the aperture of the lower air distribution plate is 5.0±0.2mm.

[0009] As a further improvement of this utility model, a natural gas combustion nozzle is also added to the side wall of the activation reactor.

[0010] As a further improvement of this utility model, the flange connection pipe is a high-temperature resistant flange pipe.

[0011] As a further improvement of this utility model, the system further includes an acid leaching system, which is connected to the outlet of the activation reactor through a conveying pipe; the acid leaching system includes a primary acid leaching chamber and a secondary acid leaching chamber, which are connected to the secondary acid leaching chamber through a reflux pipe, and the reflux pipe is equipped with a flow control valve.

[0012] Compared with the prior art, the beneficial effects of this utility model are: 1. Effectively reduces the escape rate of fine particles: Through the synergistic effect of swirling mixing and ultrasonic atomization in the fine powder agglomeration module, the fine fly ash and binder are efficiently agglomerated and coarsened, reducing the number of ultrafine particles that can be entrained by the airflow from the source. Combined with the unique three-layer gradient air distribution plate structure, the aperture gradually decreases from bottom to top, effectively breaking up large air bubbles, uniformly distributing airflow, eliminating channeling, and significantly improving bed stability, thereby greatly reducing the escape rate of fine particulate matter. 2. Improved system operational stability: The gradient air distribution plate structure significantly reduces bed pressure drop fluctuations, resulting in smoother system operation. The increased particle size after agglomeration also reduces the risk of equipment blockage during conveying and processing. 3. Achieve modular and efficient integration: The activation reactor and the gas-solid heat exchange bed are sealed and connected by a high-temperature flange to form a continuous, stable and sealed conveying channel for high-temperature ash and slag. This realizes the structural coupling of the two functional modules of incineration solidification and activation reaction, which provides convenience for subsequent resource utilization. 4. Enhanced operational flexibility: The added natural gas combustion nozzle can provide an auxiliary heat source when the residual carbon content of ash and slag is insufficient, which structurally ensures the stability of the temperature field inside the activation reactor and broadens the system's adaptability to raw materials. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of the circulating fluidized bed system described in this utility model.

[0014] Figure 2 This is a cross-sectional structural diagram of the fine powder agglomerator in this utility model.

[0015] Figure 3 This is a schematic diagram of the layered structure of the gradient air distribution plate in this utility model.

[0016] The attached diagram is labeled as follows: 1. Furnace; 2. Primary air chamber; 5. Cyclone separator; 6. Material leg; 8. Tail flue; 14. Gas-solid heat exchange bed; 22. Conveying pipeline; 23. Activation reactor; 235. Residual carbon combustion chamber; 236. Natural gas supplementary combustion nozzle; 238. Gradient air distribution plate; 238a. Upper gradient air distribution plate; 238b. Middle gradient air distribution plate; 238c. Lower gradient air distribution plate; 24. Acid leaching system; 241. Primary acid leaching chamber; 242. Secondary acid leaching chamber; 243. Return pipeline; 244. Flow control valve; 25. High-temperature resistant flange pipeline; 26. Gasification fly ash nozzle; 27. Aggregator; 271. Cyclone mixing chamber; 272. Ultrasonic atomizer; 28. Feed inlet nozzle; 29. ​​Ammonia injection pipe. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0018] Please see Figures 1 to 3 This utility model provides a circulating fluidized bed system for treating gasified fly ash.

[0019] like Figure 1As shown, the main structure of the system includes a furnace 1, with a primary air chamber 2 at its bottom for introducing fluidizing air. The top outlet of the furnace 1 is connected to the inlet of a cyclone separator 5, and the bottom of the cyclone separator 5 returns the separated solid particles to the lower part of the furnace 1 via a feed leg 6. The gas outlet of the cyclone separator 5 is connected to a gas-solid heat exchange bed 14, and the finally treated flue gas is discharged through a tail flue 8.

[0020] The key improvement of this utility model lies in the addition of three functional modules and the optimization of the structure of the core components: The fine powder agglomeration module includes an agglomerator 27 and a gasified fly ash spray gun 26. For example... Figure 2 As shown, the agglomerator 27 is its core component, which contains a swirling mixing chamber 271 and an integrated ultrasonic atomizer 272. Gasified fly ash and a binder (such as water glass solution) from the feed nozzle 28 enter the swirling mixing chamber 271 together. Under the combined action of the swirling flow field and ultrasonic atomization, they are fully mixed and agglomerated, forming particles with a larger diameter. The agglomerated material is then sprayed into the dilute phase zone at the top of the furnace 1 through the gasified fly ash spray gun 26.

[0021] The heavy metal solidification module mainly consists of an ammonia injection pipe 29. This ammonia injection pipe 29 is welded to the side wall of the furnace 1, with its opening located at a specific position 1-2 meters below the outlet of the gasification fly ash spray gun 26. This location ensures that ammonia gas can be injected into the core area of ​​the incineration reaction, allowing for sufficient contact and reaction with the volatilized heavy metals.

[0022] The core of the activation reaction module is the activation reactor 23. This reactor is sealed to the solid particle outlet of the gas-solid heat exchange bed 14 via a flanged connection pipe 25. This flanged connection ensures that high-temperature ash can be continuously, stably, and sealed to the activation reactor 23, while also facilitating equipment installation and maintenance. The bottom of the activation reactor 23 is equipped with three layers of gradient air distribution plates 238 for introducing oxygen-enriched gas and uniformly distributing the airflow. Figure 3As shown, the gradient air distribution plate 238 consists of three layers: the bottom layer is the lower gradient air distribution plate 238c, with an aperture of 5.0±0.2mm; the middle layer is the middle gradient air distribution plate 238b, with an aperture of 3.0±0.2mm; and the top layer is the upper gradient air distribution plate 238a, with an aperture of 1.0±0.1mm. This unique structure, with the aperture gradually increasing from top to bottom, effectively breaks up the airflow, distributes the air evenly, eliminates channeling, significantly improves fluidization quality, and reduces the escape of fine particles. Tests showed that after adopting the three-layer gradient air distribution plate with the specific aperture and hierarchical structure, the system bed pressure drop fluctuation was reduced from 35% with a traditional single-layer air distribution plate to below 8%, improving stability by approximately 77%; simultaneously, the fine particulate matter escape rate was significantly reduced from 28% with a single-layer air distribution plate to approximately 9.2%, a reduction of 67.1%. The internal space of the activated reactor 23 constitutes the residual carbon combustion chamber 235. In addition, a natural gas combustion nozzle 236 can be added to the side wall of the activation reactor 23 to supplement heat when the residual carbon content of the ash is too low.

[0023] As an extension of the system's resource utilization, the system may further include an acid leaching system 24, which is connected to the outlet of the activation reactor 23 via a conveying pipe 22. The acid leaching system 24 includes a primary acid leaching chamber 241 and a secondary acid leaching chamber 242, which are connected by a return pipe 243. A flow control valve 244 is installed on the return pipe 243 to control the direction and flow rate of the liquid, enabling the cascade utilization of the solvent. It should be noted that the physical connection between the acid leaching system 24 and the activation reactor 23, as a downstream processing device, is also part of the system structure of this invention.

[0024] The working principle of this utility model is as follows: Extremely fine gasified fly ash is agglomerated and ultrasonically atomized within the agglomerator 27, forming larger particles with the binder. These particles are then fed into the furnace 1 through the gasified fly ash spray gun 26. This physically increases the particle size, reducing the possibility of the particles being directly entrained and escaping by the flue gas. Ammonia gas is injected into the furnace through an ammonia injection pipe 29 at a specific height, where it can be thoroughly mixed with the fly ash. After being cooled by the gas-solid heat exchange bed 14, the incinerated ash is fed into the activation reactor 23 through a sealed high-temperature flange pipe 25. At the bottom of the activation reactor 23, oxygen-enriched gas is uniformly introduced through a unique three-layer gradient air distribution plate 238, keeping the ash in a stable fluidized state, allowing the residual carbon to burn. The structure of the gradient air distribution plate effectively suppresses the separation of fine particles. Finally, the activated ash enters the subsequent acid leaching system 24 through the conveying pipe 22 for resource recovery.

[0025] This invention effectively solves the technical problems of fine particulate matter escaping easily, uneven fluidization, and poor connection between system modules through the above-mentioned specific physical structure improvements. The structure design is reasonable and the effect is significant.

Claims

1. A circulating fluidized bed system for treating gasified fly ash, comprising a furnace (1), a primary air chamber (2), a cyclone separator (5), a feed leg (6), a gas-solid heat exchange bed (14), and a tail flue (8), characterized in that, Also includes: a. Fine powder agglomeration module, which includes a gasification fly ash spray gun (26) located at the top of the furnace (1) and an agglomerator (27) connected to the gasification fly ash spray gun (26). The agglomerator (27) is provided with a swirling mixing chamber (271) and an ultrasonic atomizer (272) inside. The agglomerator (27) is also connected to a feed nozzle (28) for inputting binder. b. Heavy metal solidification module, which includes an ammonia injection pipe (29) disposed on the side wall of the furnace (1), the ammonia injection pipe (29) being located 1-2 meters below the outlet of the gasification fly ash spray gun (26); c. Activation reaction module, which includes an activation reactor (23), the activation reactor (23) being sealed to the solid particle outlet of the gas-solid heat exchange bed (14) via a flange connection pipe (25); the bottom of the activation reactor (23) is provided with a three-layer gradient air distribution plate (238), and a residual carbon combustion chamber (235) is provided inside it.

2. A circulating fluidized bed system for treating gasified fly ash according to claim 1, characterized in that: The three-layer gradient air distribution plate (238) includes an upper gradient air distribution plate (238a), a middle gradient air distribution plate (238b), and a lower gradient air distribution plate (238c) arranged from top to bottom; the upper gradient air distribution plate (238a) has an aperture of 1.0±0.1mm, the middle gradient air distribution plate (238b) has an aperture of 3.0±0.2mm, and the lower gradient air distribution plate (238c) has an aperture of 5.0±0.2mm.

3. A circulating fluidized bed system for treating gasified fly ash according to claim 1, characterized in that: A natural gas combustion nozzle (236) is also added to the side wall of the activation reactor (23).

4. A circulating fluidized bed system for treating gasified fly ash according to claim 1, characterized in that: The flange connection pipe (25) is a high-temperature resistant flange pipe.

5. A circulating fluidized bed system for treating gasified fly ash according to any one of claims 1 to 4, characterized in that: The system also includes an acid leaching system (24), which is connected to the outlet of the activation reactor (23) via a delivery pipe (22); the acid leaching system (24) includes a primary acid leaching chamber (241) and a secondary acid leaching chamber (242), which are connected via a return pipe (243), and the return pipe (243) is equipped with a flow control valve (244).

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