CN217815044U

CN217815044U - Adjustable secondary air valve for circulating fluidized bed boiler

Info

Publication number: CN217815044U
Application number: CN202221946843.7U
Authority: CN
Inventors: 陈才炜; 刘洪升
Original assignee: Suzhou Xingzhi Environmental Protection Technology Co ltd
Current assignee: Suzhou Xingzhi Environmental Protection Technology Co ltd
Priority date: 2022-07-27
Filing date: 2022-07-27
Publication date: 2022-11-15
Anticipated expiration: 2032-07-27

Abstract

The utility model discloses an adjustable secondary air valve for a circulating fluidized bed boiler, which comprises a valve body, a valve core, a nozzle, an adjustable valve rod and an adjusting device, wherein one end of the valve body is provided with an opening, a working runner communicated with the opening is arranged in the valve body, and an air inlet runner matched with the working runner is arranged on the side surface of the valve body; the nozzle is arranged at the opening of the valve body; the valve core is arranged in the working flow passage and is matched with the nozzle in an alignment way, the adjustable valve rod is inserted into the working flow passage from the tail end of the valve body and is connected with the valve core, and the adjusting device is connected with the adjustable valve rod and is used for controlling the adjustable valve core to drive the valve core to move along the axis of the flow passage, so that the matching gap between the valve core and the nozzle is adjusted, and the air pressure is adjusted. The utility model discloses an adjustable overgrate air valve door of optimal design, adjustment overgrate air valve door opening effectively reduce furnace center oxygen deficiency core, ensure the combustion efficiency of coal carbon granule to improve the burn-off rate.

Description

Adjustable secondary air valve for circulating fluidized bed boiler

Technical Field

The utility model relates to a secondary air valve, specific adjustable secondary air valve is used to circulating fluidized bed boiler of jet distance adjustable that says so.

Background

Circulating fluidized bed boilers are the most industrialized clean coal combustion technology. The circulating fluidized bed boiler adopts fluidized combustion, and the main structure comprises a combustion chamber and a circulating furnace. The biggest difference from the bubbling fluidized bed combustion technology is that the operation wind speed is high, heterogeneous reaction processes such as combustion, desulfurization and the like are strengthened, the boiler capacity can be expanded to the large capacity which can be accepted by the power industry at present, and the circulating fluidized bed boiler well solves the basic problems such as thermal, mechanical and material science and the engineering problems such as expansion, abrasion and overtemperature, and becomes an advanced technology for utilizing the energy of the difficult-to-burn solid fuel.

The circulating fluidized bed boiler has the characteristics of wide fuel adaptability, strong load regulation, excellent environmental protection performance and the like, is rapidly developed in China, and except for a 600MW supercritical circulating fluidized bed boiler unit, more than one hundred circulating fluidized bed boiler units with 300-350 MW grades are put into operation in China. The fluidized bed boiler units play an important role in comprehensive utilization of resources, improvement of power supply structures and environmental protection in China. At present, most circulating fluidized bed boilers are combusted after combustion due to the fact that oxygen-poor cores exist in the central region of a hearth when running, various coal and carbon particles with high carbon content are mixed in a cyclone separator in a cyclone mode and are combusted continuously, coke particles and volatile matters which are not combusted in the cyclone separator enter a tail flue, and therefore the tail flue detection port detects that the content of carbon monoxide in flue gas is high and the carbon content of fly ash is high, the carbon monoxide is as high as 300-3000 mg/cubic meter (the carbon monoxide is converted into standard coal, loss is quite remarkable), and the carbon content of the fly ash is higher than 10%. Causing a decrease in the combustion efficiency and thermal efficiency of the circulating fluidized bed boiler. In the combustion process of the fluidized bed boiler, primary air mainly plays a role in fluidizing bed materials and simultaneously supplements oxygen for combustion of fuel in a dense-phase zone, oxygen in secondary air can ensure full combustion of the fuel, and the secondary air has the functions of assisting fluidization, increasing mixing of gas and solid phases, strengthening mass transfer and heat transfer, a combustion process and the like besides the function of supplementing combustion. The proportion of primary air and secondary air is adjusted, so that the original NOx emission concentration is reduced, the desulfurization efficiency is improved, and meanwhile, certain influence is brought to the reduction of boiler abrasion.

However, most of air valves of the secondary air system of the existing fluidized bed boiler are of a fixed structure and do not have a function of adjusting the distance of jet flow, so that the requirement of secondary air supply of the boiler cannot be well met. The situation is represented by the situation that secondary air flows against the side wall, the oxygen content at the periphery of the hearth is high, and the oxygen content at the center of the hearth is low. And when the boiler is under low load, the pressure head of the secondary fan descends, the material on the upper part of the hearth falls back to the secondary air nozzle and the diffusion corner area of the hearth, the material concentration in the area is higher, and a high-concentration material internal circulation state is formed in the area. The area is just the position of the secondary air nozzle, and at the moment, the pressure head of the secondary nozzle is low, the penetrating jet flow has insufficient rigidity and cannot reach the central area, and an oxygen-deficient core is formed in the central area.

In conclusion, the intelligent adjustable secondary air valve system for the circulating fluidized bed boiler is provided, and has important significance in the field.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome the not enough that prior art exists, provide an adjustable overgrate air valve suitable for circulating fluidized bed secondary air supply usefulness.

In order to achieve the above purpose, the utility model adopts the technical scheme that: an adjustable secondary air valve for a circulating fluidized bed boiler comprises a valve body, a valve core, a nozzle, an adjustable valve rod and an adjusting device, wherein one end of the valve body is opened, a working flow passage communicated with the opening is arranged in the valve body, and an air inlet flow passage matched with the working flow passage is arranged on the side surface of the valve body; the nozzle is arranged at the opening of the valve body; the valve core is arranged in the working flow passage and is matched with the nozzle in an alignment way, the adjustable valve rod is inserted into the working flow passage from the tail end of the valve body and is connected with the valve core, and the adjusting device is connected with the adjustable valve rod and is used for controlling the adjustable valve core to drive the valve core to move along the axis of the flow passage, so that the matching gap between the valve core and the nozzle is adjusted, and the air pressure is adjusted.

Furthermore, the valve body comprises a body, an auxiliary body, a tail cover and a central shaft frame, wherein the auxiliary body is connected with the body; the body is hollow, two ends of the body are opened, one end of the body is a front opening matched with the nozzle, the other end of the body is a rear opening matched with the tail cover, and a working flow channel is formed in the center of the body; the auxiliary body is hollow and provided with an opening, and an air inlet flow channel connected with the working flow channel is formed through the hollow structure; the central shaft bracket is arranged in the working flow channel and is used for being matched with the adjustable valve rod, supporting and enabling the adjustable valve rod to move along the axial direction; the center of the tail cover is provided with a mounting opening, the adjustable valve rod is inserted into the working flow passage through the mounting opening, and the fit clearance between the mounting opening and the adjustable valve rod is filled with sealing filler.

Further, the adjusting device is one of an electric adjusting device, a manual adjusting device and a pneumatic adjusting device.

Further, the nozzle is one of a tapered cone nozzle and a laval nozzle.

Furthermore, the valve core is olive-shaped, and the shape of the valve core is matched with the shape and the size of the flow passage of the spray pipe.

Furthermore, the tail end of the adjustable valve rod is connected with a hand wheel adjusting device arranged on the tail cover, and the depth of the adjustable valve rod in the working flow passage can be adjusted through the hand wheel adjusting device.

Furthermore, a sealing gasket is arranged in the connecting and matching surface of the valve body and the nozzle.

Still further, the sealing filler is a graphite filler.

More specifically, the sealing pad is a metal graphite wound pad.

The utility model discloses during the implementation, through the depth of controlling adjustable valve rod, can realize the regulation in case and nozzle clearance, realize the regulation to the wind pressure through adjusting this clearance, finally realize that the efflux distance of secondary air supply is far and near adjustable.

The utility model discloses an optimal design's adjustable overgrate air valve, adjustment overgrate air valve opening, and then improve the efflux rigidity and intensity and the length of piercing through of overgrate air, cause further NOx and SO 2's emission, effectively reduce furnace center lean oxygen core, mutual friction and striking between the reinforcing coal carbon granule promote its coal granule and the abundant mixed production oxidation reaction of oxygen, ensure the combustion efficiency of coal carbon granule to improve the burn-off rate.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the specification and together with the description, serve to explain the principles of the specification.

FIG. 1 is a schematic structural view of example 1.

Fig. 2 is a schematic structural view of the valve body of embodiment 1 after position adjustment.

FIG. 3 is a schematic view of the nozzle structure of example 1.

FIG. 4 is a schematic sectional view showing the structure of embodiment 1.

FIG. 5 is a schematic view of the structure of the circulating fluidized bed boiler to which embodiment 1 is applied.

FIG. 6 is a schematic structural view of embodiment 2.

Fig. 7 is a schematic structural view of the valve body of embodiment 2 after position adjustment.

FIG. 8 is a schematic view of the nozzle structure of example 2.

FIG. 9 is a schematic structural view of embodiment 3.

Fig. 10 is a schematic structural view in another operating state of embodiment 3.

FIG. 11 is a schematic view of the structure of embodiment 4.

Detailed Description

Various exemplary embodiments of the present specification will now be described in detail with reference to the accompanying drawings.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses.

It should be noted that like reference numerals and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

In the description of the present invention, it should be noted that the terms "vertical", "upper", "lower", "horizontal", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention.

In the description of the present invention, it is also to be understood that the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly unless otherwise specifically indicated and limited. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

Example 1:

as shown in fig. 1-5, a secondary air valve using a tapered conical nozzle 1 structure and a hand wheel adjusting device 2 is shown, and structurally, a valve body 3 comprises a main body 4, an auxiliary body 5, a tail cover 6 and a central shaft bracket 7, wherein the auxiliary body 5 is connected with the main body 4; the body 4 is hollow and has two open ends, one end is a front opening matched with the nozzle 1, the other end is a rear opening matched with the tail cover 6, and a working flow passage 8 is formed in the center of the body 4; the secondary body 5 is hollow and provided with an opening, and an air inlet flow passage 9 connected with the working flow passage 8 is formed through the hollow structure; the central shaft bracket 7 is arranged in the working flow passage 8 and is used for being matched with the adjustable valve rod 10 and supporting and enabling the adjustable valve rod 10 to move along the axial direction; the center of the tail cover 6 is provided with a mounting opening, the adjustable valve rod 10 is inserted into the working flow passage 8 through the mounting opening, and a graphite packing 11 for sealing is filled in a fit clearance between the mounting opening and the adjustable valve rod 10. The nozzle 1 is arranged at the opening of the valve body 3; the olive-shaped valve core 12 is arranged in the working flow passage 8 and is matched with the nozzle 1 in an alignment mode, the adjustable valve rod 10 is inserted into the working flow passage 8 from the tail end of the valve body 3 and is connected with the valve core 12, the valve core 12 is controlled to move along the axis of the flow passage, the matching gap between the valve core 12 and the nozzle 1 is further adjusted, and air pressure is adjusted. The tail end of the adjustable valve rod 10 is connected with a hand wheel adjusting device 2 arranged on the tail cover, and the depth of the adjustable valve rod 10 in the working flow passage 8 can be adjusted through the hand wheel adjusting device 2.

Example 2:

fig. 6-8 show a secondary air valve structure using a laval nozzle 13 and a handwheel adjustment device 14, the rest of the structure is the same as that of embodiment 1, and the front half of the laval nozzle 13 is narrowed from large to small to middle to a narrow throat. The narrow throat then flares outward from the smaller to the larger to the opening. The gas flows under high pressure into the front half of the nozzle, passes through the narrow throat and escapes from the rear half. The structure can make the speed of the airflow change due to the change of the jet cross section area, so that the airflow is accelerated from subsonic speed to sonic speed to supersonic speed. The air outlet strength and speed can be accelerated by utilizing the structural characteristics of the air outlet device.

Example 3:

as shown in fig. 9 to 10, the secondary air valve structure using the electric adjusting device 15 and the tapered conical nozzle-like structure 16 is the same as that of embodiment 1, and in the above structure, the depth of the valve core 17 is adjusted by driving the adjustable valve rod to extend and retract by the motor, so as to achieve the purpose of adjusting and controlling the air valve.

Example 4:

as shown in fig. 11, the secondary air valve structure using the pneumatic adjusting device 18 and the tapered conical nozzle-like structure 19 is the same as that in embodiment 1, and in the above structure, the pneumatic rod is used to drive the adjustable valve rod to extend and retract, so as to adjust the depth of the valve core 20, thereby achieving the purpose of adjusting and controlling the air valve.

The foregoing description of the embodiments of the present specification has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen in order to best explain the principles of the embodiments, the practical application, or improvements made to the technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein. The scope of the application is defined by the appended claims.

Claims

1. The utility model provides a circulating fluidized bed is adjustable overgrate air valve for boiler which characterized in that: the valve comprises a valve body, a valve core, a nozzle, an adjustable valve rod and an adjusting device, wherein one end of the valve body is provided with an opening, a working flow passage communicated with the opening is arranged in the valve body, and an air inlet flow passage matched with the working flow passage is arranged on the side surface of the valve body; the nozzle is arranged at the opening of the valve body; the valve core is arranged in the working flow passage and is in alignment fit with the nozzle, the adjustable valve rod is inserted into the working flow passage from the tail end of the valve body and is connected with the valve core, and the adjusting device is connected with the adjustable valve rod and is used for controlling the adjustable valve core to drive the valve core to move along the axis of the flow passage, so that the fit clearance between the valve core and the nozzle is adjusted, and the air pressure is adjusted.

2. An adjustable overfire air valve for a circulating fluidized bed boiler as claimed in claim 1, wherein: the valve body comprises a body, an auxiliary body, a tail cover and a central shaft bracket, wherein the auxiliary body is connected with the body; the body is hollow, two ends of the body are opened, one end of the body is a front opening matched with the nozzle, the other end of the body is a rear opening matched with the tail cover, and a working flow channel is formed in the center of the body; the auxiliary body is hollow and provided with an opening, and an air inlet flow passage connected with the working flow passage is formed through the hollow structure; the central shaft bracket is arranged in the working flow channel and is used for being matched with the adjustable valve rod, supporting and enabling the adjustable valve rod to move along the axial direction; the center of the tail cover is provided with a mounting opening, the adjustable valve rod is inserted into the working flow passage through the mounting opening, and the fit clearance between the mounting opening and the adjustable valve rod is filled with sealing filler.

3. An adjustable overfire air valve for a circulating fluidized bed boiler as claimed in claim 1, wherein: the adjusting device is one of an electric adjusting device, a manual adjusting device and a pneumatic adjusting device.

4. An adjustable overfire air valve for a circulating fluidized bed boiler as claimed in claim 1, wherein: the nozzle is one of a tapered cone-mounted nozzle and a laval nozzle.

5. An adjustable overfire air valve for a circulating fluidized bed boiler as claimed in claim 1, wherein: the valve core is olive-shaped, and the shape of the valve core is matched with the shape and the size of a flow passage of the spray pipe.

6. An adjustable overfire air valve for a circulating fluidized bed boiler as claimed in claim 1, wherein: and a sealing gasket is arranged in the connecting and matching surface of the valve body and the nozzle.

7. An adjustable overfire air valve for a circulating fluidized bed boiler as claimed in claim 1, wherein: the sealing filler is graphite filler.

8. An adjustable overfire air valve for a circulating fluidized bed boiler as claimed in claim 6, wherein: the sealing gasket is a metal graphite winding gasket.