1000MW-grade circulating fluidized bed boiler
By dividing the furnace into symmetrical furnace chambers and adopting a spanned structure and cyclone separator, the problems of uneven combustion and difficult maintenance of existing circulating fluidized bed boilers under high parameters and high capacity are solved, achieving more efficient combustion and reduced pollutants.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- DONGFANG BOILER GROUP OF DONGFANG ELECTRIC CORP
- Filing Date
- 2025-04-29
- Publication Date
- 2026-04-21
AI Technical Summary
Existing 350-660MW supercritical circulating fluidized bed boilers cannot meet the requirements of generator sets with higher parameters and higher capacity, and there are problems such as difficult maintenance, excessive flue gas deviation, and uneven heating.
The furnace is divided into two symmetrical furnace chambers by multiple water-cooled partition walls. It adopts a span-shaped structure and cyclone separators to enhance the penetration of secondary air. Multiple cyclone separators are configured to improve separation efficiency, and a compact layout is adopted to facilitate maintenance.
It achieves a balance between flue gas pressure and material inside the furnace, improves combustion uniformity and efficiency, reduces pollutant emissions, enhances the ability to capture fine particles, and has a compact structure that facilitates maintenance.
Smart Images
Figure CN224150915U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of fluidized bed boiler technology, and specifically relates to a 1000MW-class circulating fluidized bed boiler. Background Technology
[0002] With the continuous development of circulating fluidized bed combustion technology and the increasing requirements for coal consumption and power generation efficiency of generator sets, the existing 350-660MW supercritical circulating fluidized bed boilers will not be able to meet the higher requirements for generator sets in the future. Circulating fluidized bed boilers with higher parameters and higher capacity are bound to be the future development direction.
[0003] Currently, thermal power generating units worldwide have reached ultra-supercritical and above, with power generation efficiency improved by 3% to 4% compared to supercritical units, and also offering higher economic benefits. Therefore, the research and development of ultra-supercritical and high-efficiency ultra-supercritical circulating fluidized bed boilers is an urgent problem to be solved. During the process of increasing the heat capacity of circulating fluidized bed boilers, the furnace cross-sectional area also needs to be increased to ensure the rationality of the flue gas velocity in the furnace section. Simultaneously, issues such as the penetration of secondary air, the uniformity of materials within the furnace, and the compactness of the layout need to be addressed.
[0004] In the development of 1000MW-class circulating fluidized bed boilers, various structural designs have been proposed, such as annular furnaces and dual furnaces. However, these designs have encountered problems such as difficult maintenance, excessive flue gas deviation, and uneven heating. Therefore, a new technology is needed that is both rationally designed and capable of solving these aforementioned problems. Utility Model Content
[0005] To address the aforementioned problems in existing technologies, the present invention aims to provide a 1000MW-class circulating fluidized bed boiler. As the boiler capacity increases, a larger cross-section furnace and separators are required. This is achieved by dividing the furnace into two symmetrical chambers using multiple water-cooled partition walls, with at least eight cyclone separators symmetrically arranged on both sides of the furnace. This results in a more compact structural arrangement and improved space utilization. A reasonable gap is set between the water-cooled partition walls to address the issues of flue gas pressure and material balance within the two furnace chambers. Furthermore, a spanned structure is adopted at the bottom of the furnace to solve problems such as incomplete combustion, reduced efficiency, and increased pollutant emissions caused by the increased furnace cross-sectional size and insufficient secondary air penetration.
[0006] The technical solution adopted in this utility model is as follows:
[0007] A 1000MW-class circulating fluidized bed boiler includes a furnace, the interior of which is divided into symmetrical two-sided furnace chambers by multiple water-cooled partition walls, with gaps between adjacent water-cooled partition walls. The lower part of the furnace is a span-shaped structure including two spans, each span corresponding to one of the two-sided furnace chambers. A wind chamber is connected to the lower part of the span, and an air distribution plate is installed between the span and the wind chamber. A primary air nozzle is arranged on the outer side of the wind chamber, and secondary air nozzles are arranged on both the outer and inner walls of the span. Separator outlet flues are correspondingly provided on both sides of the furnace chamber, and at least four cyclone separators are connected between the separator outlet flues and the upper part of the furnace chamber. The boiler also includes a tail flue, with the separator outlet flues on both sides connected to the tail flue.
[0008] This invention divides the furnace into two chambers using multiple adjacent, gap-filled water-cooled partition walls, ensuring internal flue gas pressure and material balance, and improving combustion uniformity. The lower part of the furnace adopts a spanned structure, with secondary air entering the furnace from the inner and outer walls of each span, ensuring air penetration, improving efficiency, and reducing pollutant emissions. This invention employs at least eight cyclone separators to enhance the capture of fine particles, thereby improving separation efficiency, extending the residence time of fine fuel particles in the furnace, and further increasing efficiency.
[0009] The overall structure of this utility model is compact, and all parts are easy to inspect and maintain.
[0010] As a preferred embodiment of this utility model, a plurality of secondary air nozzles on the outer side wall of the support span are arranged along the depth direction of the support span, and a plurality of secondary air nozzles on the inner side wall of the support span are arranged along the depth direction of the support span. Both the inner and outer secondary air nozzles are arranged along the depth direction, and the two sides are symmetrical about the center line of the boiler. This arrangement can reduce the width of the dense phase zone in the lower part of the furnace and ensure the penetration of the secondary air.
[0011] As a preferred embodiment of this utility model, the furnace cavity is equipped with a plurality of medium-temperature superheaters and a plurality of high-temperature superheaters / reheaters, with the medium-temperature superheaters and high-temperature superheaters / reheaters in the furnace cavities on both sides arranged symmetrically around the boiler centerline; the high-temperature superheaters / reheaters are either high-temperature superheaters or high-temperature reheaters. The furnace interior is equipped with multiple screen-type heating surfaces, including medium-temperature superheaters, high-temperature superheaters, and high-temperature reheaters, and these heating surface structures can be L-shaped or U-shaped screens.
[0012] As a preferred embodiment of this utility model, the furnace cavity is equipped with several medium-temperature superheaters and several high-temperature superheaters / reheaters, with the medium-temperature superheaters and high-temperature superheaters / reheaters in both sides of the furnace cavity arranged symmetrically about the boiler centerline; the high-temperature superheaters / reheaters are either high-temperature superheaters or high-temperature reheaters. Arranging the cyclone separators and the screen-type heating surfaces located in the furnace in an axially symmetrical manner also ensures good flow field uniformity.
[0013] As a preferred embodiment of this utility model, a slag cooler is arranged below the air chamber. The slag cooler is connected to the slag discharge port on the inner side wall of the lower part of the support, so as to achieve a compact arrangement of the furnace and the external circulation loop, without external heat exchanger, and with a small footprint.
[0014] In a preferred embodiment of this invention, a return feeder is connected to the bottom of the cyclone separator. The return feeder has two return legs, the lower part of which is connected to a support. The return feeder and return legs return the material separated by the cyclone separator to the furnace.
[0015] As a preferred embodiment of this utility model, the lower inclined section of the return leg is provided with a coal feed port.
[0016] As a preferred embodiment of this utility model, the upper section of the tail flue is provided with a double flue, which includes a front flue and a rear flue. A low-temperature reheater is arranged in the front flue, and a low-temperature superheater is arranged in the rear flue.
[0017] As a preferred embodiment of this utility model, several flue gas baffles are arranged at the outlet of the dual flue to adjust the flue gas volume after the dual flue is combined, thereby adjusting the reheat steam temperature.
[0018] As a preferred embodiment of this utility model, the lower section of the tail flue is a combined flue, and an upper economizer, an SCR reactor, and a lower economizer are sequentially arranged in the combined flue.
[0019] The beneficial effects of this utility model are as follows:
[0020] This invention divides the furnace into two chambers using multiple adjacent, gap-filled water-cooled partition walls, ensuring internal flue gas pressure and material balance, and improving combustion uniformity. The lower part of the furnace adopts a spanned structure, with secondary air entering the furnace from the inner and outer walls of each span, ensuring air penetration, improving efficiency, and reducing pollutant emissions. This invention employs at least eight cyclone separators to enhance the capture of fine particles, thereby improving separation efficiency, extending the residence time of fine fuel particles in the furnace, and further increasing efficiency.
[0021] The overall structure of this utility model is compact, and all parts are easy to inspect and maintain. Attached Figure Description
[0022] Figure 1 This is a side view of the present invention in Embodiment 1;
[0023] Figure 2 This is the front view of the present invention in Embodiment 1;
[0024] Figure 3 This is a top view of the present invention in Embodiment 1;
[0025] Figure 4This is a top view of the present invention in Embodiment 2.
[0026] In the diagram: 1-Furnace; 2-Cyclone separator; 3-Return feeder; 4-Separator outlet flue; 5-Tail flue; 6-Primary air nozzle; 7-Secondary air nozzle; 8-Air preheater; 9-Low-temperature reheater; 10-Low-temperature superheater; 11-First-stage economizer; 12-SCR reactor; 13-Medium-temperature superheater; 14-High-temperature superheater; 15-High-temperature reheater; 16-Coal feed port; 17-Water-cooled partition wall; 18-Wind chamber; 19-Flue gas damper; 20-Air distribution plate; 21-Slag cooler; 22-Upper economizer; 23-Lower economizer. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0028] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other.
[0029] Example 1:
[0030] like Figures 1-3 As shown, the 1000MW-class circulating fluidized bed boiler of this embodiment includes a furnace 1. The furnace 1 is divided into two symmetrical furnace chambers by multiple water-cooled partition walls 17. The water-cooled partition walls 17 are located on the center line of the boiler, and there is a gap between two adjacent water-cooled partition walls 17. The lower part of the furnace 1 is a span-shaped structure including two spans, which correspond one-to-one with the two furnace chambers. The lower part of the span is connected to the air chamber 18. An air distribution plate 20 is provided between the span and the air chamber 18. A primary air nozzle 6 is arranged on the outside of the air chamber 18. A secondary air nozzle 7 is arranged on both the outer and inner walls of the span. A separator outlet flue 4 is provided on both sides of the furnace chamber. At least four cyclone separators 2 are connected between the separator outlet flue 4 and the upper part of the furnace chamber. It also includes a tail flue 5, and the separator outlet flues 4 on both sides are connected to the tail flue 5.
[0031] This invention divides the furnace chamber 1 into two side chambers using multiple adjacent water-cooled partition walls 17 with gaps, ensuring the balance of flue gas pressure and materials inside the furnace chamber 1 and improving combustion uniformity. The lower part of the furnace chamber 1 adopts a spanned structure, with secondary air entering the furnace chamber 1 from the inner and outer walls of each span, ensuring the penetration of secondary air, improving efficiency, and reducing pollutant emissions. This invention employs at least eight cyclone separators 2 to enhance the capture capacity of fine particles, thereby improving separation efficiency, extending the residence time of fine fuel particles in the furnace, and increasing efficiency. The overall structure of this invention is compact, and all parts are easy to maintain.
[0032] Multiple primary air nozzles 6 are symmetrically arranged on the outer sides of the two air chambers 18. Primary air enters the air chambers 18 from multiple points on both sides of the furnace 1. Secondary air inlets are arranged on both the outer and inner walls of the furnace 1, and for distinction, they can be referred to as external secondary air and internal secondary air. External secondary air enters the furnace cavities on both sides through secondary air nozzles 7 set on the outer wall of the furnace 1, while internal secondary air enters the furnace cavities on both sides through secondary air nozzles 7 set on the inner walls of the lower part of the furnace 1. Depending on the location, internal secondary air is further divided into upper internal secondary air and lower internal secondary air. Combustion aid burners can be installed on some of the secondary air nozzles 7 as needed. Both internal and external secondary air are arranged along the depth direction, and are symmetrical about the boiler centerline on both sides. This arrangement can reduce the width of the dense phase zone in the lower part of the furnace 1 and ensure the penetration of secondary air.
[0033] In this embodiment, the furnace 1 is equipped with multiple screen-type heating surfaces, including a medium-temperature superheater 13, a high-temperature superheater 14, and a high-temperature reheater 15. These heating surface structures can be L-shaped or U-shaped screens. Several medium-temperature superheaters 13, several high-temperature superheaters 14, and several high-temperature reheaters 15 are arranged symmetrically around the centerline of the boiler in the furnace cavities on both sides.
[0034] A slag cooler 21 is arranged below the air chamber 18. The slag cooler 21 is connected to the slag discharge port on the inner side wall of the lower part of the support, so as to realize the compact arrangement of the furnace 1 and the external circulation loop, without external heat exchanger, and with a small footprint.
[0035] For a 1000MW-class circulating fluidized bed boiler, the furnace 1 size is larger than that of existing supercritical circulating fluidized bed boilers. Ensuring particle concentration and heat exchange capacity of the heating surfaces in the furnace 1 region is a crucial consideration during product development, necessitating improved separator efficiency. Generally, handling larger flue gas volumes requires larger separators or an increased number of separators. However, increasing the separator diameter weakens the capture capacity for fine particles, thus reducing separation efficiency. Existing boiler thermal calculations and separator performance parameters indicate that at least eight separators are needed to meet the flue gas volume requirements of a 1000MW-class circulating fluidized bed boiler. In this embodiment, eight cyclone separators 2 are symmetrically arranged around the center of the furnace 1 to ensure uniform flow field. Four cyclone separators 2 on the same side are connected to the separator outlet flue 4 on that side. The separator outlet flue 4 can adopt an insulated steel plate structure or a steam-cooled membrane wall structure. The separator outlet flues 4 on both sides are symmetrically arranged about the boiler centerline and connect to the tail flue 5.
[0036] Furthermore, a return feeder 3 is connected to the bottom of the cyclone separator 2. The return feeder 3 has two return legs, the lower part of which is connected to a support. The return feeder 3 and the return legs send the material separated by the cyclone separator 2 back to the furnace 1. In addition, a coal feed port 16 is arranged on the lower inclined section of each return leg. The return legs connected to each return feeder 3 are arranged symmetrically along the center line of the return feeder 3, and all return feeders 3 are arranged symmetrically along the center line of the boiler.
[0037] Specifically, the tail flue 5 is configured as a dual flue, consisting of a front flue and a rear flue, with a membrane wall structure for the enclosure. The low-temperature superheater 10 and the low-temperature reheater 9 are respectively arranged in the rear and front flues, and a primary economizer 11 can be arranged in the rear flue according to actual conditions. Multiple flue gas baffles 19 are arranged at the outlet of the dual flues to regulate the flue gas volume after the dual flues are combined, thereby regulating the reheat steam temperature. In the flue after the front and rear flues are combined, a staged upper economizer 22 and a lower economizer 23 are arranged, with the SCR reactor 12 positioned between the upper economizer 22 and the lower economizer 23. Finally, two rotary air preheaters 8 are arranged in the tail flue 5.
[0038] Example 2:
[0039] like Figure 4 As shown, the cyclone separators 2 and the screen-type heating surfaces located in the furnace 1 are arranged in an axisymmetric manner, which can also ensure good flow field uniformity.
[0040] This utility model is not limited to the above-mentioned optional embodiments. Anyone can derive other forms of products under the guidance of this utility model. However, regardless of any changes made in its shape or structure, any technical solution that falls within the scope of the claims of this utility model shall be protected by this utility model.
Claims
1. A 1000 MW class circulating fluidized bed boiler, characterized by: The furnace includes a furnace chamber (1), which is divided into two symmetrical furnace chambers by multiple water-cooled partition walls (17), with a gap between adjacent water-cooled partition walls (17). The lower part of the furnace chamber (1) is a span-shaped structure with two support spans, which correspond one-to-one with the two furnace chambers. The lower part of the support span is connected to a wind chamber (18), and an air distribution plate (20) is provided between the support span and the wind chamber (18). A primary air nozzle (6) is arranged on the outside of the wind chamber (18), and a secondary air nozzle (7) is arranged on both the outer and inner walls of the support span. A separator outlet flue (4) is provided on both sides of the furnace chamber, and at least four cyclone separators (2) are connected between the separator outlet flue (4) and the upper part of the furnace chamber. The furnace also includes a tail flue (5), and the separator outlet flues (4) on both sides are connected to the tail flue (5).
2. A 1000 MW class circulating fluidized bed boiler according to claim 1, characterized in that: The secondary air nozzles (7) on the outer wall of the support span are arranged along the depth direction of the support span, and the secondary air nozzles (7) on the inner wall of the support span are arranged along the depth direction of the support span.
3. A 1000 MW class circulating fluidized bed boiler according to claim 1, characterized in that: The furnace cavity is provided with a number of medium-temperature superheaters (13) and a number of high-temperature superheaters and reheaters. The number of medium-temperature superheaters (13) and a number of high-temperature superheaters and reheaters in the furnace cavities on both sides are arranged symmetrically around the center line of the boiler. The high-temperature superheaters and reheaters are high-temperature superheaters (14) or high-temperature reheaters (15).
4. A 1000 MW class circulating fluidized bed boiler according to claim 1, characterized in that: The furnace cavity is provided with a number of medium-temperature superheaters (13) and a number of high-temperature superheaters and reheaters. The number of medium-temperature superheaters (13) and a number of high-temperature superheaters and reheaters in the furnace cavities on both sides are arranged symmetrically about the boiler centerline. The high-temperature superheaters and reheaters are high-temperature superheaters (14) or high-temperature reheaters (15).
5. A 1000 MW class circulating fluidized bed boiler according to claim 1, characterized in that: A slag cooler (21) is arranged below the air chamber (18), and the slag cooler (21) is connected to the slag discharge port on the inner side wall of the lower part of the support.
6. A 1000 MW class circulating fluidized bed boiler according to claim 1, characterized in that: The bottom of the cyclone separator (2) is connected to a return feeder (3), which has two return legs connected to it. The lower part of the return legs is connected to the support.
7. A 1000 MW class circulating fluidized bed boiler according to claim 6, characterized in that: The lower inclined section of the return leg is provided with a coal feed port (16).
8. A 1000 MW class circulating fluidized bed boiler according to claim 1, characterized in that: The upper section of the tail flue (5) is provided with a double flue, which includes a front flue and a rear flue. A low-temperature reheater (9) is arranged in the front flue, and a low-temperature superheater (10) is arranged in the rear flue.
9. A 1000 MW class circulating fluidized bed boiler according to claim 8, characterized in that: Several flue gas baffles (19) are arranged at the outlet of the dual flue.
10. A 1000 MW class circulating fluidized bed boiler according to claim 9, characterized in that: The lower section of the tail flue (5) is a combined flue, in which an upper economizer (22), an SCR reactor (12), and a lower economizer (23) are arranged in sequence.