Material returning system of circulating fluidized bed boiler
By setting up secondary air inlets and cold slag air inlets in the circulating fluidized bed boiler, combined with the design of a return feeder and a loosening air chamber, the problem of incomplete fuel combustion caused by insufficient air supply is solved, combustion efficiency and combustion adaptability are improved, and pollutant emissions are reduced.
Patent Information
- Application Number
- CN202520081330.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-14
- Publication Date
- 2026-02-27
- Estimated Expiration
- 2035-01-14
AI Technical Summary
Existing circulating fluidized bed boilers suffer from incomplete fuel combustion due to insufficient air supply, resulting in low combustion efficiency and poor combustion adaptability.
Secondary air inlets and cold slag air inlets are installed in the furnace. Secondary air is supplied through the secondary air duct to ensure complete combustion of fuel. The design of the return feeder and loosening air chamber ensures the circulation and uniform distribution of bed material, avoiding clogging problems.
It improves boiler combustion efficiency, reduces pollutant emissions, and ensures stable boiler operation and complete combustion.
Smart Images
Figure CN223954145U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a boiler technical field, concretely is a kind of circulating fluidized bed boiler return material system. BACKGROUND
[0002] Circulating fluidized bed boiler is a kind of clean combustion technology with high combustion efficiency, wide fuel applicability, low pollution emissions and wide load regulation.
[0003] At present, due to insufficient air supply of the existing circulating fluidized bed boiler, the fuel in the boiler furnace is not fully combusted, resulting in low boiler combustion efficiency, and the present application provides a circulating fluidized bed boiler to change the separation efficiency and improve the adaptability to combustion. SUMMARY
[0004] The utility model discloses a circulating fluidized bed boiler return material system to solve the problems in the above background.
[0005] To achieve the above object, the utility model provides the following technical scheme:
[0006] A circulating fluidized bed boiler return material system, comprising a furnace with a combustion chamber, the left side of the furnace is provided with a feeding point, the upper end of the right side is provided with a separator, the lower end of the separator is provided with a return material device, the bottom of the return material device is connected with the furnace, and the right side of the separator is further provided with a preheating chamber.
[0007] As a further scheme of the utility model: wherein, the inside of the furnace is provided with a wind distribution plate for placing inert bed material, and a primary air chamber is arranged below the wind distribution plate, and the primary air chamber is connected with a primary air pipe.
[0008] As a further scheme of the utility model: wherein, the furnace is provided with an opening, and the furnace has a first flue gas outlet, a primary air inlet, a secondary air inlet, a cold slag air inlet, a bottom slag outlet and a feeding port in communication with the cavity; the first flue gas outlet communicates the separator with the furnace; the primary air inlet is in communication with the primary air chamber; the bottom slag outlet is located at the bottom of the furnace and connected with a bottom slag cooler.
[0009] As a further scheme of the utility model: wherein, the feeding point is arranged on one side wall of the furnace and located close to the bed layer, and from bottom to top, there are a limestone feeding port and a first coal feeding port, the limestone feeding port is communicated with a limestone bin through a pipeline, the first coal feeding port is connected with a first coal feeding pipe, and the first coal feeding pipe is communicated with a coal feeder through a first coal air pipe.
[0010] As a further scheme of the utility model: wherein, the angle of the first coal feeding pipe is downward, and the included angle between the first coal feeding port and the horizontal plane is 35-45 degrees.
[0011] As a further scheme of the utility model: wherein, the separator's lower end is fixedly connected with a return pipe riser, the separator's upper end is provided with a tail flue, the return feeder is located at the lower end of the return pipe riser, the inner chamber bottom of the return feeder is respectively provided with a loosening air chamber and a conveying air chamber, the lower end of the loosening air chamber and the conveying air chamber is respectively connected with a first air supply pipeline and a second air supply pipeline, and the discharge end of the return feeder is provided with a return pipe connected with the bottom of the furnace chamber lateral wall.
[0012] As a further scheme of the utility model: wherein, the return feeder is a U-shaped valve structure, has a chamber, a return pipe riser inlet, a return port and an ash discharge port communicated with the chamber, the return pipe is communicated with the return port, and a coal feeding port is formed in the return pipe.
[0013] As a further scheme of the utility model: wherein, the included angle between the coal feeding port on the return pipe and the axis of the return pipe is 0-15 degrees.
[0014] As a further scheme of the utility model: wherein, the preheating chamber comprises a superheater, a reheater, a coal economizer and an air preheater arranged from top to bottom in the flue of the separator flue gas outlet, and the air preheater inlet is respectively connected with a primary air fan conveying pipeline and a secondary air fan conveying pipeline.
[0015] Compared with the prior art, the utility model has the advantages that:
[0016] In the system, a plurality of secondary air inlets and cold slag air inlets are arranged in the furnace chamber, part of the secondary air supplied by the secondary air duct is sent into the furnace chamber through the air inlets to provide oxygen for the fuel in the furnace chamber, so that the fuel in the furnace chamber is fully burned, the combustion efficiency of the fuel in the boiler is improved, and the problem of low combustion efficiency of the boiler caused by insufficient air supply of the traditional fluidized bed boiler and insufficient combustion of the fuel in the furnace chamber is overcome.
[0017] In addition, the key role of the return feeder is to ensure the circulating flow of the bed material, improve the combustion efficiency and reduce the emission of pollutants. In the return chamber, the bed material is fully mixed and separated, the fine particles are returned to the furnace chamber through the return pipe, and the coarse particles are left in the return chamber to continue to be crushed and mixed. The regulating valve is used to control the return flow to ensure the uniform distribution of the bed material in the furnace chamber. The separate arrangement of the loosening air chamber and the conveying air chamber in the return feeder facilitates the control of the air speed in different areas and avoids the problem of blockage at the bottom of the U-shaped valve. BRIEF DESCRIPTION OF DRAWINGS
[0018] Fig. 1 It is a system overall schematic view in the utility model;
[0019] Fig. 2 It is a return feeder schematic view in the utility model;
[0020] The correspondence between the reference signs of the figures and the component names is as follows:
[0021] 10, furnace; 11, air distribution plate; 12, primary air chamber; 13, primary air pipe; 14, first flue gas outlet; 15, primary air inlet; 16, secondary air inlet; 17, cold slag air inlet; 18, bottom slag outlet; 19, feed inlet; 20, separator; 21, return material standpipe; 22, tail flue; 30, return material feeder; 31, air distribution chamber; 32, conveying air chamber; 33, first air supply pipeline; 34, second air supply pipeline; 40, bottom slag cooler; 50, preheating chamber; 51, superheater; 52, reheater; 53, economizer; 54, air preheater; 55, primary air fan conveying pipeline; 56, secondary air fan conveying pipeline. DETAILED DESCRIPTION
[0022] In the following, only certain exemplary embodiments are described simply. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present application. Therefore, the drawings and the description are considered to be exemplary in nature rather than limiting.
[0023] Please refer to Figs. 1-2 : A circulating fluidized bed boiler return material system, comprising a furnace 10 with a combustion chamber, the left side of the furnace 10 is provided with a feeding point, the upper end of the right side is provided with a separator 20, the lower end of the separator 20 is provided with a return material feeder 30, and the bottom of the return material feeder 30 is connected with the furnace 10. In this embodiment, the flue gas in the combustion chamber enters the separator 20 from the air inlet, the material ash in the flue gas falls into the return material feeder 30 after being separated by the separator 20, and the material ash in the return material feeder 30 returns to the combustion chamber from the return material port. The right side of the separator 20 is also provided with a preheating chamber 50. In order to avoid the increase of the return material ash amount of the return material feeder inducing the low temperature operation of the boiler, the return material ash control device is arranged in the return material feeder 30 of the circulating fluidized bed boiler, which can automatically or manually discharge the ash, so as to adjust the return material ash amount of the combustion chamber, thereby achieving the purpose of stabilizing the operation condition of the boiler.
[0024] The inside of the furnace 10 is provided with an air distribution plate 11 for placing inert bed material, the lower side of the air distribution plate 11 is provided with a primary air chamber 12, the primary air chamber 12 is connected with a primary air pipe 13, the top of the primary air chamber 12 is connected with a dense phase zone of the furnace, the top of the dense phase zone of the furnace is connected with a dilute phase zone of the furnace, and the separator is arranged at the right side of the dilute phase zone of the furnace. The bottom of the furnace 10 is also provided with a thermocouple for temperature detection, and the lower side and the upper side (i.e. the dense phase zone and the dilute phase zone) of the inner cavity of the furnace 10 are respectively provided with a pressure measuring point P1 and a pressure measuring point P2, and the pressure difference of the furnace 10 is calculated by the pressure difference value of P1 and P2.
[0025] The furnace chamber 10 is open and has a first flue gas outlet 14, a primary air inlet 15, a secondary air inlet 16, a cold slag air inlet 17, a bottom slag outlet 18, and a feed inlet 19. The first flue gas outlet 14 connects the separator 20 to the furnace chamber 10. The primary air inlet 15 is connected to the primary air chamber 12. The bottom slag outlet 18 is located at the bottom of the furnace chamber 10 and is connected to the bottom slag cooler 40. The bottom slag cooler 40 uses cooling circulating water and cold slag air for cooling. After cooling, the residual cooling air is transported to the lower part of the furnace chamber 10, and the cooled bottom slag is transported to the stacking point by a scraper conveyor located below.
[0026] The feeding point is located on one side wall of the furnace 10 and near the bed layer. From bottom to top, it is a limestone feeding port and a first coal feeding port. The limestone feeding port is connected to the limestone silo through a pipe. The first coal feeding port is connected to the first coal feeding pipe. The first coal feeding pipe is connected to the coal feeder through the first coal air pipe. (The bottom of the storage silo is connected to the feeder. The feeder has a feed pipe at the feeding end. The feeding end of the feed pipe extends to the coal inlet of the furnace. The air source of the coal feeding fan is from the hot primary air. Since its usage is very small and it only plays a pressurizing role, its capacity and power are small. It is also possible not to set up a coal feeding fan and directly use the primary air as the coal feeding air.)
[0027] The following points should be noted regarding the setting of feeding points: 1. There should be no fewer than two feeding points for both coal and limestone; 2. In terms of the bed cross-sectional area handled by a single feeding point, for a circulating bed, each feeding point is responsible for 8 to 35 square meters of bed surface; 3. The number of feeding points varies depending on the fuel properties. For example, for high volatile coal, the feeding point is generally placed below the dense phase zone in the bed height direction, and the position is determined with reference to the system pressure balance.
[0028] Furthermore, the first coal feeding pipe is angled downwards, the angle between the first coal feeding opening and the horizontal plane is 35-45 degrees, and the angle between the coal feeding point opening on the return pipe and the axis of the return pipe is 0-15 degrees.
[0029] The lower end of the separator 20 is fixedly connected to the return riser 21, and the upper end of the separator 20 is provided with a tail flue 22.
[0030] The inner cavity bottom of the return feeder 30 is respectively provided with a loosening air chamber 31 and a conveying air chamber 32, the lower ends of the loosening air chamber 31 and the conveying air chamber 32 are respectively connected with a first air feeding pipe 33 and a second air feeding pipe 34, and the discharge end of the return feeder 30 is provided with a return pipe 35 connected with the bottom of the side wall of the furnace 10. The air inlet ends of the first air feeding pipe 33 and the second air feeding pipe 34 are respectively provided with a first return air fan 36 and a second return air fan 37, and the first air feeding pipe 33 and the second air feeding pipe 34 are respectively provided with a first air regulating valve and a second air regulating valve, the first air feeding pipe 33 is provided with an air feeding branch pipe connected with the feeding pipe and provided with a branch pipe air regulating valve, and the air feeding branch pipe is connected to the feeding opening on the return vertical pipe feeder 21 to assist feeding and avoid the problem of accumulation and blockage on the return vertical pipe.
[0031] Further, the return feeder 30 is a U-shaped valve structure, has a cavity, a feeding opening of the return vertical pipe feeder 21, a return opening and an ash discharging opening communicated with the cavity, the return pipe 35 is communicated with the return opening, and the return pipe 35 is provided with a coal feeding opening. The return feeder 30 is further provided with a return opening, and a material ash control device is installed to automatically or manually discharge ash, to adjust the return amount of the return ash and avoid the problem of return accumulation on the U-shaped valve air distribution plate.
[0032] The preheating chamber 50 includes a superheater 51, a reheater 52, an economizer 53 and an air preheater 54 arranged from top to bottom in the flue of the flue gas outlet of the separator 20, the air preheater 54 is respectively connected with a primary air fan conveying pipe 55 and a secondary air fan conveying pipe 56, the primary air after passing through the air preheater 54 is conveyed to the primary air chamber 12 at the bottom of the furnace 10, a part of the secondary air is conveyed into the furnace 10 through the secondary air opening of the furnace wall, and the other part is connected with the first air feeding pipe 33 of the return feeder 20.
[0033] Further, a plurality of secondary air openings are arranged at a height of 0.5-0.7m from the air distribution plate of the furnace, and the secondary air openings are communicated with the secondary air pipe through a pipe.
[0034] The blowing angle of the secondary air opening is obliquely downward, and the included angle between the secondary air opening and the horizontal plane is 35-45°. The system can realize the continuous and stable operation of the circulating fluidized bed boiler through the air flow generated by the return air fan to suck the bed material from the bottom of the boiler furnace to the return chamber and then return to the furnace through the return pipe.
[0035] The above is only a preferred specific implementation manner of the present application, but the protection scope of the present application is not limited to this, any skilled person in the art can make equivalent replacement or change according to the technical scheme and the application concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.
Claims
1. A circulating fluidized bed boiler return system, characterized in that, The application relates to a furnace comprising a furnace chamber (10) with a combustion chamber, a feeding point arranged on the left side of the furnace chamber (10), a separator (20) arranged at the upper end of the right side of the furnace chamber (10), a return feeder (30) arranged at the lower end of the separator (20), and a preheating chamber (50) arranged on the right side of the separator (20).
2. A circulating fluidized bed boiler return system according to claim 1, characterized in that, The inside of the furnace chamber (10) is provided with a wind distribution plate (11) for placing inert bed materials, and a primary air chamber (12) is arranged below the wind distribution plate (11) and connected with a primary air pipe (13).
3. A circulating fluidized bed boiler return system according to claim 1, characterized in that, The furnace chamber (10) is provided with an opening, and the furnace chamber (10) is provided with a first flue gas outlet (14) in communication with a cavity, a primary air inlet (15), a secondary air inlet (16), a cold slag air inlet (17), a bottom slag outlet (18) and a feeding port (19); the first flue gas outlet (14) is in communication with the separator (20) and the furnace chamber (10); the primary air inlet (15) is in communication with the primary air chamber (12); the bottom slag outlet (18) is located at the bottom of the furnace chamber (10) and is connected with a bottom slag cooler (40).
4. A circulating fluid bed boiler return system according to claim 1, characterized in that, The feeding point is arranged on one side wall of the furnace chamber (10) and is located close to the bed layer, and the feeding point is provided with a limestone feeding port and a first coal feeding port from bottom to top; the limestone feeding port is connected with a limestone bin through a pipeline; the first coal feeding port is connected with a first coal feeding pipe; and the first coal feeding pipe is connected with a coal feeder through a first coal air pipe.
5. A circulating fluid bed boiler return system according to claim 4, characterized in that, The angle of the first coal feeding pipe is downwardly inclined, and the included angle between the first coal feeding port and the horizontal plane is 35-45 degrees.
6. A circulating fluid bed boiler return system according to claim 1, characterized in that, The lower end of the separator (20) is fixedly connected with a return feeder standpipe (21), the upper end of the separator (20) is provided with a tail flue (22), the return feeder (30) is located at the lower end of the return feeder standpipe (21), the inner cavity bottom of the return feeder (30) is respectively provided with a loosening air chamber (31) and a conveying air chamber (32), the lower ends of the loosening air chamber (31) and the conveying air chamber (32) are respectively connected with a first air supply pipe (33) and a second air supply pipe (34), and the discharge end of the return feeder (30) is provided with a return pipe (35) connected with the bottom of the side wall of the furnace chamber (10).
7. A circulating fluid bed boiler return system according to claim 6, characterized in that The return feeder (30) is a U-shaped valve structure and is provided with a cavity, a return feeder standpipe (21) feeding port in communication with the cavity, a return port and an ash discharge port; the return pipe (35) is in communication with the return port; and a coal feeding port is formed in the return pipe (35).
8. A circulating fluid bed boiler return system according to claim 7, characterized in that The included angle between the coal feeding port of the return pipe (35) and the axis of the return pipe (35) is 0-15 degrees.
9. A circulating fluid bed boiler return system according to claim 1, characterized in that, The preheating chamber (50) comprises a superheater (51), a reheater (52), an economizer (53) and an air preheater (54) arranged from top to bottom in the flue gas outlet flue of the separator (20); and the air preheater (54) inlet is respectively connected with a primary air fan conveying pipeline (55) and a secondary air fan conveying pipeline (56).