A fluidized control material distribution system for an external fluidized bed heat exchanger

Abstract

The application discloses a fluidized control material distribution system for an external fluidized bed heat exchanger, which comprises a furnace, at least one cyclone separator is communicated with the upper end of the furnace, the lower end of the cyclone separator is communicated with an upper-layer return feeder loose bed, the lower side of the upper-layer return feeder loose bed is communicated with an upper-layer return feeder conveying bed, the upper-layer return feeder conveying bed comprises a plurality of independent first cavities, each first cavity is communicated with a distribution unit, and the distribution units are communicated with the lower end of the furnace; the distribution unit comprises independent second cavities and third cavities, a convection heat exchanger and an external loose bed located below the convection heat exchanger are arranged in the second cavities and the third cavities; the second cavities are communicated with the lower end of the furnace from bottom to top through external conveying beds, and the third cavities are communicated with the lower end of the furnace from top to bottom through external overflow beds, and the fluidized control material distribution system has the technical characteristics of being capable of distributing materials for a plurality of external fluidized beds, simple structure, and improved service life.

Description

Technical Field

[0001] This invention relates to a material distribution system, and more specifically, to a fluidized bed heat exchanger fluidized control material distribution system, belonging to the field of thermal energy engineering application technology. Background Technology

[0002] External fluidized bed heat exchangers are one of the key components of high-parameter circulating fluidized bed boilers, but they have the following disadvantages: 1) External fluidized beds passively participate in material distribution, and can only distribute materials one-to-one with cyclone separators, not one-to-many, and cannot actively distribute the amount of material. They passively receive the material separated by the separator, and are greatly affected by the separation efficiency of the separator; 2) Traditional external bed heat exchangers are single-stage return structures. The cavity volume of traditional external beds is small, and only a small number of heating surfaces (convection heat exchangers) can be arranged. They must be combined with the inner screen heating surface in the furnace to meet the requirements of material heat balance. They cannot meet the absorption of material heat balance on their own, and the cooling effect on the material is not obvious; 3) The cavity volume of external fluidized beds is small, and the material accumulation height is low. When the return amount is insufficient, the heating surface is easily exposed to the flue gas and is easily eroded and worn by the return ash. It is also easily corroded by high temperature in corrosive atmospheres; 4) When the heating surface is arranged in the external bed conveyor bed, the material flow rate is high, and the windward side of the lower part of the heating surface is easily eroded and worn. 5) Steam parameter adjustment methods are limited, only allowing for water spraying for temperature reduction on the steam side. 6) At low loads, the heating surfaces are prone to overheating, resulting in a short service life. Summary of the Invention

[0003] To address the aforementioned problems in the prior art, this invention provides a fluidized bed heat exchanger fluidization control material distribution system with the technical characteristics of having a separator capable of distributing materials to multiple external fluidized beds, simple structure, and extended service life.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0005] A fluidized bed heat exchanger fluidized bed control material distribution system includes a furnace, at least one cyclone separator is connected to the upper end of the furnace, the lower end of the cyclone separator is connected to an upper return feeder loosening bed, an upper return feeder conveying bed is connected below the upper return feeder loosening bed, the upper return feeder conveying bed includes multiple independent No. 1 chambers, each No. 1 chamber is connected to a material distribution unit, and each material distribution unit is connected to the lower end of the furnace;

[0006] The material distribution unit includes two independent cavities, namely, a second cavity and a third cavity. Both cavities are equipped with an external loosening bed and a convection heat exchanger located within the external loosening bed. The second cavity is connected to the lower end of the furnace from bottom to top via an external conveying bed, and the third cavity is connected to the lower end of the furnace from top to bottom via an external overflow bed.

[0007] Preferably, the external conveying bed includes a longitudinally arranged No. 1 feeding channel, the bottom of which is the feeding end and the top of which is the discharging end. The top of the No. 1 feeding channel is connected to the lower end of the furnace, and the bottom of the No. 1 feeding channel is connected to the external loosening bed in the No. 2 cavity.

[0008] Preferably, the external overflow bed includes a longitudinally arranged second feeding channel, the top of which is the inlet end and the bottom of which is the outlet end. The bottom of the second feeding channel is connected to the lower end of the furnace, and the top of the second feeding channel is connected to the third cavity. The height of the top of the second feeding channel is higher than the height of the convection heat exchanger in the third cavity.

[0009] Preferably, the top of the second feeding channel extends with a baffle that slopes towards the third cavity to efficiently guide the material in the third cavity into the second feeding channel and into the furnace.

[0010] Preferably, the discharge end of the second feeding channel is provided with a downward sloping ramp to avoid material accumulation at the discharge end of the second feeding channel.

[0011] Preferably, the outer wall of the No. 1 feeding channel located in the furnace is inclined downward to avoid material accumulation at the discharge end and outer wall of the No. 1 feeding channel.

[0012] Preferably, the outlet end of the cyclone separator is provided with an inclined baffle to achieve efficient flow of material to the upper return feeder loose bed.

[0013] Preferably, the furnace is connected to a No. 1 pipe for air supply, and the No. 1 pipe is connected to a regulating damper and a primary air fan;

[0014] Preferably, the No. 1 feeding channel of the external conveying bed and the external loosening bed in the No. 2 cavity are both connected to the No. 2 pipeline, and the No. 2 pipeline is connected to an adjusting damper. The two No. 2 pipelines converge and are connected to the external bed return fan.

[0015] Preferably, the upper return material loosening bed and the upper return material conveying bed are both connected to a No. 3 pipeline, and an adjusting damper is connected to the No. 3 pipeline. The No. 3 pipeline is then connected to the upper return material return fan.

[0016] Beneficial effects: During operation, the distribution of materials and heat can be ideally achieved by adjusting the fan air volume, air pressure, and damper opening. At the same time, it can also increase the means of steam-side desuperheater, reducing the pressure of steam-side load adjustment. One cyclone separator can distribute materials to multiple external fluidized beds and can actively distribute the amount of material. The structure is simple and easy to operate. The material distribution unit includes independent No. 2 and No. 3 cavities, each with a separate convection heat exchanger (heating surface), which increases the area of ​​the heating surface and allows the heating surface to be completely embedded in the material, resulting in excellent material cooling effect, meeting the material heat balance requirements, and ensuring that the furnace temperature is stable within a certain range. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0018] Figure 2 This is a cross-sectional view at point AA of the present invention.

[0019] Figure 3 This is a cross-sectional view at point BB of the present invention.

[0020] Figure 4 This is a cross-sectional view at the CC position of the present invention.

[0021] 1-Furnace chamber; 2-Cyclone separator; 3-Upper return feeder loose bed; 4-Upper return feeder conveying bed; 5-Convection heat exchanger; 6-External bed loose bed; 7-External bed conveying bed; 8-External bed overflow bed; 9-Primary air fan; 10-External bed return air fan; 11-Upper return feeder return air fan; 12-Regulating damper; 13-Distribution unit; 14-Cavity No. 2; 15-Cavity No. 3. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings, but the present invention is not limited to the following embodiments.

[0023] like Figure 1-4 The illustration shows a specific embodiment of a fluidized bed heat exchanger fluidized control material distribution system. This embodiment of a fluidized bed heat exchanger fluidized control material distribution system includes a furnace 1. At least one cyclone separator 2 is connected to the upper end of the furnace 1. The lower end of the cyclone separator 2 is connected to an upper return feeder loose bed 3. An upper return feeder conveying bed 4 is connected below the upper return feeder loose bed 3. The upper return feeder loose bed 3 and the upper return feeder conveying bed 4 constitute an upper return feeder.

[0024] The upper return feeder conveying bed 4 includes multiple independent No. 1 chambers, each of which is connected to a material distribution unit 13. These multiple material distribution units 13 form an external bed assembly. Each material distribution unit 13 is connected to the lower end of the furnace 1. Each material distribution unit 13 includes independent No. 2 cavities 14 and No. 3 cavities 15. Both No. 2 cavities 14 and No. 3 cavities 15 are equipped with an external loosening bed 6 and a convection heat exchanger 5 located within the external loosening bed 6. One inventive implementation of this application is that No. 2 cavity 14 is connected to the lower end of the furnace 1 from bottom to top via an external conveying bed 7, and No. 3 cavity 15 is connected to the lower end of the furnace 1 from top to bottom via an external overflow bed 8. Figure 1 The diagram shows two cyclone separators 2 configured with three material distribution units 13, enabling one cyclone separator 2 to distribute materials to multiple external fluidized beds (material distribution units 13). Since the upper return material loosening bed 3 is an integral chamber, and the upper return material loosening bed 3 is connected to the upper return material conveying bed 4 which has multiple independent No. 1 chambers, and then connected to multiple material distribution units 13 through multiple independent No. 1 chambers, it solves the technical defects of the current technology, such as one external fluidized bed can only distribute materials to cyclone separators one-to-one, and cannot distribute materials to multiple units or actively allocate material quantity.

[0025] Process Flow / Principle: The high-temperature flue gas from the furnace 1 of the fluidized bed boiler carries a large amount of material. After being separated by the cyclone separator 2, the material enters the upper return feeder loose bed 3. The upper return feeder loose bed 3 is a single chamber where the material can flow freely. The upper return feeder conveying bed 4 is equipped with partition walls, allowing multiple independent No. 1 chambers to be formed within it. The partition walls separate the materials, and the number of partition walls can be set according to actual needs. Figure 1 The diagram illustrates one method used in this application: the space is divided into three chambers (Channel 1) by two partition walls. The amount of material entering the external loosening bed 6 and / or external conveying bed 7 is adjusted by regulating the airflow of the upper return material loosening bed 3 and / or the upper return material conveying bed 4. Specifically, the airflow is adjusted via pipeline 3, regulating damper 12, and the upper return material return fan 11. The external bed (material distribution unit 13) contains the external loosening bed 6, the external conveying bed 7, and the external overflow bed 8.

[0026] The external loosening bed 6 serves only to maintain the flow of bed material; the internal material flow velocity is extremely low, and it does not cause wear on the heating surface (the surface of the convection heat exchanger 5). The external conveying bed 7 has a high material flow velocity, but it is completely isolated from the heating surface (convection heat exchanger 5). The amount of material flowing through the heating surface is adjusted by regulating the airflow of the external conveying bed 7. Specifically, this is achieved through the second pipeline, the regulating damper 12, and the external bed return fan 10, thus adjusting the heat exchange between the material and the heating surface. In this application, the heating surface (convection heat exchanger 5) is located inside the external loosening bed 6 and can be completely buried within the material, serving to isolate corrosive fumes and buffer against scouring as the material falls. Another innovation in this application is that when there is excess material, the excess material can be returned to the furnace 1 through the external overflow bed 8, so that the total amount of material in the external bed remains stable. Specifically, when the material accumulation above the convection heat exchanger 5 in the third cavity 15 is higher than the feed inlet at the upper end of the second feeding channel, it can gradually enter the furnace 1 through the second feeding channel. The baffle inclined towards the third cavity 15 can efficiently guide the material in the third cavity 15 to the second feeding channel and flow into the furnace 1.

[0027] In this application, the heating surface within the external bed (material distribution unit 13) can be an economizer, superheater, convection heat exchanger, or reheater, etc. In this application, a convection heat exchanger 5 is preferred. The heating surfaces can be connected in parallel or in series. When superheaters are used and connected in series, desuperheaters can be installed between the superheaters to regulate the steam temperature. After the material is cooled, it enters the furnace 1 to cool the furnace 1 and stabilize the furnace 1 temperature within a certain range.

[0028] Figure 1 This is a schematic diagram of the overall structure of the invention. The cyclone separator 2 separates a large amount of material, which enters the upper return feeder loosening bed 3. The upper return feeder loosening bed 3 is a single chamber connected to the upper return feeder conveying bed 4. The upper return feeder conveying bed 4 is divided into different chambers, each separated by a partition wall. A partition wall is also provided between the external bed conveying bed 7 and the external bed overflow bed 8, meaning that the second cavity 14 and the third cavity 15 are independently designed. The number and size of the external bed conveying bed 7 and the external bed overflow bed 8 can be adjusted according to actual needs, such as... Figure 1 As shown, each material distribution unit 13 employs two external conveying beds 7 and an external overflow bed 8.

[0029] Figure 2 for Figure 1Cross-sectional view at point AA (flowchart of upper layer return material and external bed heat exchange return material). The high-temperature flue gas generated by fuel combustion in furnace 1 carries a large amount of circulating material into cyclone separator 2. Cyclone separator 2 separates a large amount of material. Fine particles and flue gas enter the tail heating surface. The separated material enters the upper return feeder loose bed 3. After being distributed by the upper return feeder conveying bed 4, it enters the external bed (distribution unit 13) and exchanges heat with the convection heat exchanger 5. After passing through the external bed loose bed 6 and external bed conveying bed 7, it returns to furnace 1. The primary air fan 9 is used to support the fluidization of material in furnace 1 and to support combustion. The external bed return air fan 10, in conjunction with the regulating damper 12, is used to support the fluidization and conveying of material in the external bed (distribution unit 13), the external bed conveying bed 7, and the second cavity 14. The upper return feeder return air fan 11, in conjunction with the regulating damper 12, is used to support the fluidization and conveying of material in the upper return feeder (upper return feeder loose bed 3 and upper return feeder conveying bed 4). The regulating damper 12 is used to adjust the pipeline resistance, thereby distributing the air volume in different areas of the return feeder and the external bed.

[0030] Figure 3 for Figure 1 Cross-sectional view at section BB (flowchart of upper layer return material and external bed overflow). The high-temperature flue gas generated by fuel combustion in furnace 1 carries a large amount of circulating material into cyclone separator 2. Cyclone separator 2 separates a large amount of material. Fine particles and flue gas enter the tail heating surface. The separated material enters the upper return feeder loose bed 3. After being distributed by the upper return feeder conveying bed 4, it enters the external bed and exchanges heat with the convection heat exchanger 5. When the material is higher than the external bed weir (i.e., the feed inlet at the upper end of the second feeding channel) and exceeds the material quantity required by the external bed, it returns directly to the furnace through the external bed overflow bed 8 without heat exchange, thus maintaining a stable bed material quantity in the external bed. The primary air fan 9 is used to support the fluidization of material in the furnace and to support combustion. The external bed return air fan 10 is used to support the fluidization and conveying of material in the external bed. The upper return feeder return air fan 11 is used to support the fluidization and conveying of material in the upper return feeder. The regulating damper 12 is used to adjust the pipeline resistance to distribute the air volume in different areas of the return feeder and the external bed.

[0031] Figure 4 The cross-sectional view at CC (chamber division diagram of the upper return feeder and the external bed return feeder) is described as above. Figure 3 The descriptions are consistent.

[0032] In this invention: 1. By adjusting the return air system, a material distribution system with actively adjustable characteristics is provided;

[0033] 2. One cyclone separator can distribute materials to multiple external fluidized beds (distribution units);

[0034] 3. The external bed has a large cavity (specifically, the second and third cavities in the material distribution unit are designed separately and have a large cavity), providing sufficient heating surface, which can fully meet the absorption of material heat balance in the fluidized bed boiler.

[0035] 4. The heating surface is located inside the external loose bed, which can be completely buried in the return ash, isolating it from corrosive flue gas, resulting in less high-temperature corrosion and less material wear;

[0036] 5. The steam (pipeline medium) side of the heating surface can be connected in parallel or in series. When connected in series, the steam parameters can be adjusted by both water spraying for cooling and material quantity.

[0037] 6. At low loads, the pipes will not overheat because the material covers the heating surface, resulting in a long service life for the heating surface.

[0038] In a preferred embodiment, the external conveying bed 7 includes a longitudinally arranged first feeding channel, with its bottom as the inlet and its top as the outlet. The top of the first feeding channel is connected to the lower end of the furnace 1, and its bottom is connected to the external loosening bed 6 in the second cavity 14. The external overflow bed 8 includes a longitudinally arranged second feeding channel, with its top as the inlet and its bottom as the outlet. The bottom of the second feeding channel is connected to the lower end of the furnace 1, and its top is connected to the third cavity 15. The height of the top of the second feeding channel is higher than the height of the convection heat exchanger 5 in the third cavity 15.

[0039] The design of external conveyor bed 7 and external overflow bed 8 makes the material change highly flexible, which can not only keep the total amount of material in the external bed stable, but also realize the rapid flow of materials.

[0040] In a preferred embodiment, the top of the second feeding channel extends with a baffle that slopes towards the third cavity 15 to efficiently guide the material in the third cavity 15 into the second feeding channel and then into the furnace 1. The discharge end of the second feeding channel has a downward-sloping ramp to prevent material accumulation at the discharge end. The outer wall of the first feeding channel located within the furnace 1 is sloped downwards to prevent material accumulation at the outlet and on the outer wall of the first feeding channel.

[0041] In a preferred embodiment, the outlet end of the cyclone separator 2 is provided with an inclined baffle to efficiently direct the material to the upper return feeder loosening bed 3.

[0042] In the preferred embodiment, the regulating damper 12, the primary air fan 9, the external bed return air fan 10, the upper return air fan 11, the first pipeline, the second pipeline, and the third pipeline constitute the regulating return air system. Among them, the primary air fan 9, the external bed return air fan 10, and the upper return air fan 11 are all fans.

[0043] The furnace chamber 1 is connected to a first pipeline for air supply, which is connected to an regulating damper 12 and a primary air fan 9. The first feeding channel of the external conveying bed 7 and the external loosening bed 6 in the second cavity 14 are both connected to a second pipeline, which is connected to an regulating damper 12. The two second pipelines converge and are connected to an external bed return fan 10. The upper return loosening bed 3 and the upper return conveying bed 4 are both connected to a third pipeline, which is connected to an regulating damper 12. The three pipelines converge and are connected to an upper return fan 11.

[0044] Finally, it should be noted that the present invention is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A fluidized bed heat exchanger fluidized bed control material distribution system, characterized in that: The furnace includes a furnace chamber (1), the upper end of which is connected to at least one cyclone separator (2), the lower end of which is connected to the upper return material loosening bed (3), the lower part of which is connected to the upper return material conveying bed (4), the upper return material conveying bed (4) includes multiple independent first chambers, each first chamber is connected to a material distribution unit (13), and the material distribution unit (13) is connected to the lower end of the furnace chamber (1); The material distribution unit (13) includes an independent second cavity (14) and a third cavity (15). Both the second cavity (14) and the third cavity (15) are equipped with an external loosening bed (6) and a convection heat exchanger (5) located in the external loosening bed (6). The second cavity (14) is connected to the lower end of the furnace (1) from bottom to top through an external conveying bed (7), and the third cavity (15) is connected to the lower end of the furnace (1) from top to bottom through an external overflow bed (8). The external conveying bed (7) includes a first feeding channel arranged longitudinally. The bottom of the first feeding channel is the feeding end, the top of the first feeding channel is the discharging end, the top of the first feeding channel is connected to the lower end of the furnace (1), and the bottom of the first feeding channel is connected to the external loosening bed (6) in the second cavity (14). The external overflow bed (8) includes a second feeding channel arranged longitudinally. The top of the second feeding channel is the feeding end, the bottom of the second feeding channel is the discharging end, the bottom of the second feeding channel is connected to the lower end of the furnace (1), the top of the second feeding channel is connected to the third cavity (15), and the height of the top of the second feeding channel is higher than the height of the convection heat exchanger (5) in the third cavity (15). The top of the No. 2 feeding channel extends with a baffle that is inclined toward the No. 3 cavity (15) to efficiently guide the material in the No. 3 cavity (15) into the No. 2 feeding channel and into the furnace (1). The discharge end of the second feeding channel is equipped with a downward-sloping ramp to prevent material accumulation at the discharge end of the second feeding channel.

2. The fluidized bed heat exchanger fluidized bed control material distribution system according to claim 1, characterized in that: The outer wall of the No. 1 feeding channel located in the furnace (1) is inclined downward to avoid material accumulation at the discharge end and outer wall of the No. 1 feeding channel.

3. The fluidized bed heat exchanger fluidized bed control material distribution system according to claim 1, characterized in that: The cyclone separator (2) has an inclined baffle at the outlet end to efficiently flow the material to the upper return feeder loose bed (3).

4. A fluidized bed heat exchanger fluidized bed control material distribution system according to claim 1, characterized in that: The furnace (1) is connected to a No. 1 pipe for air supply, and the No. 1 pipe is connected to an regulating damper (12) and a primary air fan (9).

5. A fluidized bed heat exchanger fluidized bed control material distribution system according to claim 1, characterized in that: The No. 1 feeding channel of the external conveying bed (7) and the external loosening bed (6) in the No. 2 cavity (14) are both connected to the No. 2 pipeline. The No. 2 pipeline is connected to the regulating damper (12). The two No. 2 pipelines converge and are connected to the external bed return fan (10).

6. A fluidized bed heat exchanger fluidization control material distribution system according to claim 1, characterized in that: The upper return material loosening bed (3) and the upper return material conveying bed (4) are both connected to the No. 3 pipeline, and the No. 3 pipeline is connected to the regulating damper (12). The No. 3 pipeline is connected to the upper return material return fan (11) after it converges.

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