CN218583140U - Hidden hood type multi-step circulating fluidized bed surface structure - Google Patents

Abstract

The utility model discloses a hidden hood type multi-stage circulating fluidized bed surface structure, wherein the height of a hood is sequentially reduced from the edge of a hearth to a slag discharge pipe and is arranged in a step shape; the fluidized bed surface is also in a step shape corresponding to the blast cap, the fluidized bed surface is built by wear-resistant casting materials, the blast cap is embedded in the wear-resistant casting materials, each blast cap is embedded in the casting materials to form a small plane which inclines towards the slag discharge pipe, each small plane is combined in an equal difference mode to form a stair-type step-shaped bed surface, and the whole bed surface inclines towards the slag discharge pipe from the edge of the hearth; the size of the wind cap head in the horizontal direction is larger than that in the vertical direction; the blast cap head is only provided with an air outlet on one side facing the slag discharge pipe. The whole bed surface has no fluidization dead angle, and local part has no bulge or recess; when large blocks of incombustible fall on the inclined bed surface, the large blocks of incombustible can smoothly move towards the slag falling opening at the lower end along the inclined bed surface without any blockage by means of the gravity of the large blocks of incombustible, the thrust of fluidized bed materials and the unidirectional air blowing force of the air outlet holes of the air caps, and finally enter the slag discharge pipe opening.

Description

Hidden hood type multi-step circulating fluidized bed surface structure

Technical Field

The utility model relates to a circulating fluidized bed boiler technical field, concretely relates to use furnace cloth wind device at circulating fluidized bed garbage boiler.

Background

The air distribution devices adopted by the prior fluidized bed boilers (such as bubbling beds or circulating fluidized beds) mainly have two forms, namely hood type and dense-hole plate type. The common dense-hole plate type air distribution device is not commonly used, and the most widely used air distribution device in the domestic fluidized bed boiler is the air cap type air distribution device. The wind cap type wind distribution device mainly comprises a wind chamber, a wind distribution plate, a wind cap and a heat insulation layer. Hot air entering the furnace enters the fluidization hood through the pressure equalizing air chamber, passes through the hood connecting pipe and the hood head, and then is sprayed into the hearth through the hood small holes at a high speed to form uniform fluidized air, so that the aims of uniformly fluidizing bed materials of the hearth and providing primary air required by combustion are fulfilled.

In China, the circulating fluidized bed incineration technology is used as an efficient and clean combustion technology and is more and more widely applied to garbage treatment in recent years. Because the garbage recovery system in China is still imperfect, the garbage components are relatively complex, and massive incombustible matters (such as stones, bricks and the like) and metal substances such as iron wires and the like in the garbage are inevitably brought into the furnace. Particularly, solid metal objects such as iron wires, pop cans, wine bottle caps, iron blocks and the like in the solid wastes are difficult to discharge from the slag discharge port after being softened, and the slag discharge port is easy to block; therefore, the technical difficulty in the boiler for solidifying the waste and the garbage is to solve the problem of slag discharge while ensuring smooth fluidization of the fluidized bed.

The upper surface of the hearth air distribution plate in the past is mainly planar, and the middle part of the hearth air distribution plate is provided with a slag discharge port, so that the hearth air distribution plate has the advantages of simple structure and the like, and is widely applied to circulating fluidized bed boilers. The fluidization hood mainly adopts a mushroom head type and a bell jar type; the mushroom head adopts the integral structure design, and the bell jar type is placed on the castable bed surface by the self weight of the hood head. When the circulating fluidized bed technique is applied to waste disposal, the horizontally arranged bed surface exposes its disadvantages: because the garbage components are complex, the granularity and the density of bed materials are large, in the plane type hearth bed surface structure in the prior art, because gaps exist among hood heads on the bed surface, metal, stone and the like with large specific gravity are collected at the gaps when a boiler operates, the hood heads are easy to be wound by sundries such as iron wires, the hood holes are easy to block after the boiler operates for a long time, some large particles and heavy particles are deposited on the bed surface or are accumulated around a slag discharge port, and are continuously accumulated around after being blown by fluidizing air to form a fluidizing dead zone with larger and larger area, so that the fluidizing effect of the whole bed surface is influenced, the flow uniformity and stability in the bed are greatly reduced, even the non-fluidizing state of the bottom is caused, the blockage of the slag discharge port and the coking and slagging of a hearth are easily caused, the boiler is forced to stop, and the continuous operation time of the boiler is shortened. Especially, when the slag block is arranged at the upper part of the blast cap blast hole, the wind blown out from the blast cap blast hole is blocked by the slag, the wind can only run downwards, and at the moment, the blast cap is subjected to the buoyancy of the upward wind, and the blast cap can be easily blown off, so that the boiler can not run normally.

Therefore, the arrangement of the blast cap is a key element for uniformly distributing the air in the circulating fluidized bed, directly determines the fluidization effect of the circulating fluidized bed, and also influences the combustion of the boiler. In the circulating fluidized bed boiler which operates at present, the air caps are uniformly distributed on the bed surface and protrude out of the bed surface by about 100 mm-200 mm. When the boiler is in operation, the boiler is exposed above a bed surface and is subjected to washing of a large amount of circulating materials and bottom slag during operation, the problem of abrasion exists, partial perforation and coking can be caused during serious operation, the boiler is forced to be shut down, the operation period of the boiler is shortened, the operation cost of the boiler is increased, and the operation safety and efficiency of the boiler are seriously influenced. On the other hand, because of the existence of circulating ash wall flow, the ash flow around the boiler hearth is large, if the blast cap is too close to the vertical surface of the bed around, the castable is easily blown out, and if the blast cap is slightly far away, the periphery of the bed surface has a fluidization dead angle, so that the fluidization is uneven; moreover, due to the existence of incombustible foreign matters in the fuel, particularly iron blocks, iron wires and the like contained in garbage, biomass and industrial solid waste, the foreign matters are blocked by the blast cap higher than the bed surface in the process of moving to the slag discharge port, so that the foreign matters are wound on the blast cap or clamped in the gap of the blast cap, the blast cap is blocked and then fluidization is not smooth after a long time, and the boiler is forced to stop.

Disclosure of Invention

An object of the utility model is to overcome the shortcoming that prior art exists, provide a hide multistage circulating fluidized bed surface structure of hood type to solve current circulating fluidized bed boiler when the burning contains fuel such as the more living beings of impurity, rubbish, thereby the phenomenon that the boiler blowing out is forced to bed surface coking, the slagging scorification that the fluidization is not smooth to lead to, make boiler continuous operation duration increase greatly, be showing and improve economic benefits.

The utility model discloses a realize that the technical scheme that above-mentioned purpose adopted is:

a hidden hood type multi-stage circulating fluidized bed surface structure comprises an air chamber, a water-cooling air distribution plate, a slag discharge pipe and a plurality of hoods arranged on the water-cooling air distribution plate, wherein the top wall of the air chamber is the water-cooling air distribution plate; the blast cap include that blast cap head and blast cap are taken over, the blast cap head sets up in the upper end that the blast cap was taken over, the lower extreme that the blast cap was taken over is vertical to be installed on water-cooling grid plate and to be linked together its characterized in that with the plenum: the blast caps are sequentially reduced from the edge of the hearth to the height of the slag discharge pipe and are arranged in a step shape; the fluidized bed surface is in a step shape corresponding to the blast cap, is built by wear-resistant castable, is embedded in the wear-resistant castable, and is inclined from the edge of the hearth to the slag discharge pipe; the size of the blast cap head in the horizontal direction is larger than that in the vertical direction; the hood head is only provided with an air outlet on one side facing the slag discharge pipe.

By adopting the technical scheme, the blast cap is embedded in the casting material, the casting material is used for circulating ash to wash, the problem of blast cap abrasion is basically solved, the replacement period of the blast cap is greatly prolonged, and the replacement period is prolonged from about 10% per year to 5 years for 10%; the blast caps embedded in the castable around the boiler furnace also solve the problem of uneven peripheral fluidization.

In the hidden hood type multi-step circulating fluidized bed surface structure, the height difference of two rows of adjacent hoods is arranged according to equal difference, the height difference is determined by the length of the hood connecting pipe, the whole fluidized bed surface is inclined from the edge of a hearth to a slag discharge pipe, and the included angle between the whole fluidized bed surface structure and the horizontal plane is 10-30 degrees; the section of the slag discharge pipe is waist-round.

By adopting the technical scheme, high-speed air sprayed out of the rear exhaust cap can blow through the top of the front exhaust cap, so that impact abrasion at the back of the blast cap is greatly improved, and the improvement of fluidization uniformity in the boiler and the operation period of the boiler are facilitated; after the height difference exists between the adjacent front and rear exhaust caps, the fluidized air sprayed by the rear exhaust cap directly enters the hearth, so that the disturbance at the bottom of the bed layer can be enhanced, and the particle mixing is facilitated; after the directional blast caps are arranged in a ladder way, the directional blowing capability is stronger, and the discharge of large particles and heavy particles is facilitated.

The whole fluidized bed surface is obliquely arranged from the edge of a hearth to a slag discharge pipe, and the hood head is only provided with an air outlet hole at one side facing the slag discharge pipe, when large incombustibles fall on the inclined bed surface, the large incombustibles and large ash residues are smoothly discharged by means of the gravity of the hood head, the thrust of fluidized bed materials and the blowing force of the unidirectional air of the hood air outlet hole slowly move along the inclined bed surface to a slag discharge port at the lower end and finally enter a slag discharge pipe port to avoid unsmooth slag discharge and ensure that the slag discharge port cannot be coked.

In the above hidden hood type multi-step circulating fluidized bed surface structure, each exhaust hood is embedded in the castable to form a small plane inclined towards the slag discharge pipe, the included angle between the small plane and the horizontal plane is 5-10 degrees, and each small plane is combined in an equal difference manner to form a stair type step bed surface.

By adopting the technical scheme, after the same exhaust hood is arranged on the air distribution plate, the gap between the adjacent air hoods is smaller, the reserved expansion gap is filled with a casting material, a small plane slightly inclined towards the slag discharge pipe by 5-10 degrees is formed at the upper part of the air hood, the small plane is smooth and has no protrusion or recess, the flow of bed materials is facilitated, a plurality of slightly inclined small planes are arranged in a step shape to form a bed surface structure with a larger inclination angle of 10-30 degrees, the whole bed surface has no fluidization dead angle, and the local part has no protrusion or recess; under the combined action of three factors of a flat hood shell, the blowing force of unidirectional air of the air outlet holes of the hood and the fluidized bed surface obliquely arranged towards the slag discharge pipe, when large incombustibles fall on the oblique bed surface, the large incombustibles can smoothly move towards the slag discharge port at the lower end along the oblique bed surface without any stop by means of the gravity of the large incombustibles, the thrust of fluidized bed materials and the blowing force of the unidirectional air of the air outlet holes of the hood and finally enter the slag discharge pipe opening.

In the above hidden hood type multi-stage circulating fluidized bed surface structure, the hood head comprises a hood shell and a labyrinth plate, the hood shell is a rectangular cylinder with an opening at the lower end, and the lower part of the right side wall of the hood shell is provided with at least 2 air outlet holes; the opening end of the blast cap shell is connected with a sealing plate, so that the blast cap shell forms a sealed inner cavity, the upper end of a blast cap connecting pipe penetrates through the sealing plate to be communicated with the inner cavity of the blast cap shell, and the lower end of the blast cap connecting pipe penetrates through an air distribution plate to be communicated with an air chamber; the labyrinth plate is positioned in the inner cavity of the air cap shell, the inner cavity is divided into a labyrinth air channel, the air cap connecting pipe is communicated with one end of the air channel, and the air outlet hole is communicated with the other end of the air channel.

By adopting the technical scheme, the air outlet is only arranged at the lower part of the right side wall of the air cap shell, and when the air cap is arranged on the air distribution plate, the air outlet faces the direction of the slag discharge pipe, so that slag discharge of a boiler is facilitated; the exhaust vent of unidirectional can make the fluidized bed charge produce directional flow, and the air current flow direction that forms at the bottom of a furnace can blow coarse particle bed material to the slag notch, blows big piece incombustible according to the design direction, does benefit to large granule lime-ash flow direction slag notch, discharges it smoothly to influence boiler normal operating, can also make the interior disturbance of furnace more strong, is favorable to the burning of rubbish.

Furthermore, the axis of the air outlet is inclined downwards along the air outlet direction, and the included angle between the axis and the horizontal plane is 5-10 degrees.

By adopting the technical scheme, the ejection direction of the air outlet is inclined downwards, the fluidization is more uniform, the possibility of coking is reduced, and the abrasion caused by blowing the adjacent blast caps by air flow is avoided; meanwhile, due to the downward-inclined structure of the air outlet holes, the turbulence in the hearth can be stronger, the combustion of garbage is facilitated, and large particles such as coal gangue in the hearth of the circulating fluidized bed boiler can not be deposited on a bed surface, so that the stable fluidization quality in the boiler and the normal operation of the boiler are ensured.

Furthermore, the total sectional area of the air outlet holes is smaller than that of the air inlet pipe.

By adopting the technical scheme, the wind power blown out by the hood is stronger, and the non-combustible materials are more easily pushed to move according to the design direction. The optimized adjustment of the hood resistance can be realized by adjusting the number of the air outlet holes.

In the above hidden hood type multi-stage circulating fluidized bed surface structure, the size of the hood housing in the horizontal direction is larger than that in the vertical direction.

When the blast cap ladder is arranged, the height difference exists between the adjacent front and rear exhaust hoods, and by adopting the technical scheme, the blast cap shell is flat, so that the height difference between the front and rear exhaust hoods can be reduced, and the problem of uneven air distribution caused by the height difference of the material level on the bed surface is reduced to a great extent.

In the hidden hood type multi-stage circulating fluidized bed surface structure, the labyrinth plate is in an inverted L shape and comprises a horizontal plate and a vertical plate which are perpendicular to each other, the front end and the rear end of the labyrinth plate are connected with and sealed with the front side wall and the rear side wall of the hood shell respectively, a first air channel is formed between the horizontal plate, the vertical plate and the sealing plate, a second air channel and a third air channel are formed between the horizontal plate and the left side wall of the hood shell and the upper side wall, the vertical plate is close to the right side wall and the lower end of the hood shell and is abutted to and sealed with the sealing plate, a fourth air channel is formed between the vertical plate and the right side wall, and the first air channel, the second air channel, the third air channel and the fourth air channel are communicated with each other to form the labyrinth air channel.

By adopting the technical scheme, after fluidized air enters the inner cavity of the hood from the air chamber through the hood connecting pipe, the flowing direction is changed from horizontal left, vertical upward and horizontal right to vertical downward, and then the fluidized air flows into the hearth from the air outlet in an inclined manner. Because the air current is through turning back many times, and the exhaust vent slope is downward, the deposit can not take place for the granule, and the big granule also is very difficult reversely leaks into the plenum, and the emergence of leaking the sediment phenomenon has effectively been avoided to its labyrinth structure.

Furthermore, the height of the air outlet is lower than that of the horizontal plate.

By adopting the technical scheme, the height of the air outlet is set to be lower than that of the horizontal plate, so that the vertical plate can further prevent the bed material from refluxing, a function of blocking the refluxing bed material is realized, and the material is difficult to flow back to the air chamber through the air outlet along with the wind.

Furthermore, the blast cap connecting pipe extends upwards to the horizontal plate and is sealed with the horizontal plate, and a plurality of air inlet holes uniformly distributed along the circumference of the blast cap connecting pipe are formed in the side surface of the upper part of the blast cap connecting pipe.

By adopting the technical scheme, after the blast cap connecting pipe extends into the inner cavity of the blast cap shell, even if bed materials enter the inner cavity, the bed materials are not easy to enter the air chamber through the blast cap connecting pipe. The number of the air inlet holes in the air cap connecting pipe and the number of the air outlet holes in the air cap shell can be adjusted to realize the optimal adjustment of the air cap resistance.

Has the advantages that:

in actual operation, primary air of the boiler enters a hearth from an air chamber through an air cap on an air distribution plate, and fluidized bed materials are filled in the hearth space. When biomass, garbage, industrial solid waste and the like containing stones and more metals fall into a hearth to be combusted, fine particle incombustible matters are fluidized along with bed materials, when large incombustible matters fall onto an inclined bed surface under the combined action of three factors of a flat hood shell, the blowing force of unidirectional wind of a hood air outlet hole and the fluidized bed surface which is obliquely arranged towards a slag discharge pipe, the large incombustible matters can slowly move along the inclined bed surface to a slag discharge port at the lower end by virtue of the gravity of the large incombustible matters, the thrust of the fluidized bed materials and the blowing force of unidirectional wind of the hood air outlet hole and finally enter the slag discharge port to smoothly discharge the large incombustible matters and large ash slag, so that the problem that the large incombustible matters and the large ash slag are smoothly discharged is solved, the coking phenomenon cannot occur at the slag discharge port is guaranteed, particularly, a slag discharge pipe port with a waist-round cross section is adopted, the arrangement of the hood is more beneficial to the slag discharge and the ash slag discharge is more favorable for the arrangement of the circular slag discharge pipe compared with the circular slag discharge pipe, and the problem that the running time of the boiler cannot be blocked when the biomass, the waste and the like containing more impurities are combusted by the circulating boiler is solved without increasing the diameter of the slag discharge pipe, and the boiler so as to greatly prolong the boiler.

Drawings

Fig. 1 is a schematic sectional view of the bed surface structure of the present invention.

Fig. 2 is a schematic top view of the bed surface structure of the present invention (the hood is disposed on the water-cooling grid plate and before the wear-resistant castable is laid on the fluidized bed surface).

Fig. 3 is a schematic plan view of the bed surface structure of the present invention (the hood is disposed on the water-cooling grid plate, and the fluidized bed surface is built with wear-resistant castable).

Fig. 4 and 5 are partially enlarged schematic views of the blast cap embedded in the wear-resistant castable in fig. 1.

Fig. 6 is a schematic structural view of the Chinese wind hat of the present invention.

Fig. 7 is a front sectional view of the Chinese cowl of the present invention.

Fig. 8 isbase:Sub>A schematic top view (base:Sub>A cross-sectional viewbase:Sub>A-base:Sub>A in fig. 7) of the blast cap of the present invention.

Fig. 9 is a left side sectional view of the Chinese wind hat of the present invention.

Fig. 10 is a right schematic view of the Chinese wind hat of the present invention.

Fig. 11 is a schematic diagram of a second embodiment of the present invention.

In the figure: 1 a wind cap head, 11 sealing plates, 12 air outlet holes, 13 wind cap shells, 14 labyrinth plates, 141 horizontal plates, 142 vertical plates, 15 first air channels, 16 second air channels, 17 third air channels and 18 fourth air channels,

2 blast cap connecting pipes, 21 air inlet holes, 3 air chambers, 4 slag discharge pipes, 5 wear-resistant casting materials and 6 water-cooling air distribution plates.

Detailed Description

In order to clearly illustrate the technical features of the present solution, the present invention is further described below by way of non-limiting examples with reference to the accompanying drawings.

The front, back, left and right directions of the utility model are described according to the front, back, left and right directions shown in the attached drawings. For ease of illustration, only the portions relevant to the embodiments of the present invention are shown.

The first embodiment is as follows:

referring to fig. 1 to 11, a hidden hood type multi-stage circulating fluidized bed surface structure comprises an air chamber 3 enclosed by water-cooled walls, a water-cooled air distribution plate 6, a slag discharge pipe 4 and a plurality of hoods arranged on the water-cooled air distribution plate 6, wherein the top wall of the air chamber 3 is the water-cooled air distribution plate 6, the slag discharge pipe 4 is arranged in the air chamber, the upper end of the slag discharge pipe 4 is connected with the water-cooled air distribution plate 6, the lower end of the slag discharge pipe 4 extends out of the air chamber 3 and then is connected with a slag discharge valve and a slag cooler, and the section of the slag discharge pipe is waist-shaped; the blast cap comprises a blast cap head 1 and a blast cap connecting pipe 2, the blast cap head 1 is arranged at the upper end of the blast cap connecting pipe 2, the lower end of the blast cap connecting pipe 2 is vertically arranged on a water-cooling air distribution plate 6 and is communicated with an air chamber 3, and the blast cap connecting pipe 2 and the water-cooling air distribution plate 6 are fixed in other modes such as welding. The blast caps are arranged in rows from the edge of the hearth to the upper opening of the slag discharge pipe 4, the heights of the blast caps are sequentially reduced and arranged in a step shape, the height difference of two adjacent rows of blast caps is arranged according to equal difference, and the height difference is determined by the length of the blast cap connecting pipe 2; the fluidized bed surface is corresponding to the blast cap and is also in a step shape, the fluidized bed surface is built by wear-resistant casting materials, the wear-resistant casting materials cover the area between the air distribution plate 6 and the upper edge of the blast cap head, the whole blast cap is embedded in the wear-resistant casting materials except the air outlet hole 12, so that the whole fluidized bed surface is inclined from the edge of the hearth to the upper opening of the slag discharge pipe 4 and is arranged in a step shape, and the included angle alpha between the whole structure of the fluidized bed surface and the horizontal plane is 10-30 degrees. Specifically, the hood head of the present embodiment has a rectangular structure, and the size of the rectangular body in the horizontal direction is 140mm × 140mm, which is larger than the size of the rectangular body in the vertical direction by 50mm; each exhaust cap is embedded into the casting material to form a small plane which inclines towards the slag discharge pipe, the included angle beta between the small plane and the horizontal plane is 5 degrees, and each small plane is combined in an equal difference mode to form a stair type step bed surface. The interval between two adjacent blast caps in each blast cap is 160mm, the distance between two adjacent blast caps is 160mm, the height difference is 60mm, and the included angle between the whole structure of the fluidized bed surface and the horizontal plane is 20 degrees.

The hood head specifically comprises a hood shell 13 and a labyrinth plate 14, the hood shell 13 is a rectangular cylinder with an opening at the lower end, and 7 air outlet holes 12 are formed in the lower part of the right side wall of the hood shell 13; the axis of the air outlet hole 12 is inclined downwards along the air outlet direction, and the included angle between the axis and the horizontal plane is 5 degrees; the opening end of the blast cap shell 13 is connected with a sealing plate 11, so that the blast cap shell 13 forms a sealed inner cavity, and a labyrinth plate 14 is positioned in the inner cavity; the size of the hood shell 3 in the horizontal direction is larger than that in the vertical direction. The labyrinth plate 14 is in an inverted L shape and is composed of a horizontal plate 141 and a vertical plate 142 which are perpendicular to each other, the width of the horizontal plate 141 in the left-right direction is larger than the height of the vertical plate 142, the front end and the rear end of the labyrinth plate 14 are respectively connected and sealed with the front side wall and the rear side wall of the hood shell 13, a first air channel 15 is formed between the horizontal plate 141 and the vertical plate 142 and the sealing plate 11, a second air channel 16 and a third air channel 17 are respectively formed between the horizontal plate 141 and the left side wall and between the upper side wall of the hood shell 13, the vertical plate 142 is close to the right side wall of the hood shell 13, the lower end of the vertical plate is connected and sealed with the sealing plate 11, a fourth air channel 18 is formed between the vertical plate 142 and the right side wall, and the first air channel 15, the second air channel 16, the third air channel 17 and the fourth air channel 18 are communicated with each other to form the labyrinth air channel. The upper end of the blast cap connecting pipe 2 passes through the sealing plate 11 to be communicated with a first air duct 15, and the lower end of the blast cap connecting pipe 2 passes through the air distribution plate to be communicated with the air chamber; thus, the labyrinth plate 14 divides the inner cavity of the hood shell into labyrinth air channels, the hood connecting pipe 2 is communicated with the first air channel 15, and the air outlet 12 is communicated with the fourth air channel 18. The height of the air outlet 12 is lower than that of the horizontal plate 141. The total cross-sectional area of the air outlet 12 is smaller than the cross-sectional area of the air inlet pipe.

The working principle of the embodiment is as follows:

when the hood is arranged on the air distribution plate, the air outlet 12 faces to the direction of the slag discharge pipe, when the boiler normally operates, primary air flows upwards from the air chamber through the lower end of the hood connecting pipe 2 and then enters the inner cavity of the hood, the flow direction is changed from horizontal left, vertical upward and horizontal right to vertical downward, and then the primary air flows into the hearth from the air outlet 12 in an inclined manner; because the air outlet 12 is only arranged at the lower part of the right side wall of the hood shell 13, the air outlet 12 in a single direction can enable fluidized bed bottom materials to generate directional flow, and under the combined action of three factors of the flat hood shell, the blowing force of the unidirectional wind of the air outlet of the hood and a fluidized bed surface obliquely arranged towards the slag discharge pipe, when large incombustibles fall on the inclined bed surface, the large incombustibles can slowly move towards the slag discharge port at the lower end along the inclined bed surface by means of the gravity of the large incombustibles, the thrust of the fluidized bed materials and the blowing force of the unidirectional wind of the air outlet of the hood and finally enter the oval slag discharge pipe port to smoothly discharge the large incombustibles and large slag. When the smoke backflow is caused by sudden change of water content in fuel, which causes sudden fluctuation of pressure in a hearth, or reduction of smoke pressure and flow due to sudden vibration of a fan and change of boiler load, the labyrinth air duct design and blocking of the vertical plate 42 of the labyrinth plate 4 can effectively prevent bed materials serving as solid particles from flowing backwards into the air return chamber.

The second embodiment:

referring to fig. 1, 3 to 7, in the present embodiment, a hidden hood type multi-stage circulating fluidized bed surface structure includes a hood adapter 2 extending upward to a horizontal plate 141 and sealed with the horizontal plate 141, and a plurality of air inlet holes 21 uniformly distributed along the circumference of the hood adapter 2 is formed in the upper side surface of the hood adapter. In the embodiment, after the blast cap connecting pipe 2 extends into the inner cavity of the blast cap shell 13, even if bed materials enter the inner cavity, the bed materials cannot easily enter the air chamber through the blast cap connecting pipe 2. The optimal adjustment of the hood resistance can also be realized by adjusting the number of the air inlet holes 21 on the hood adapter 2 and the air outlet holes 12 on the hood shell 13. The rest of the structure is the same as that of the first embodiment, and is not described again.

The working principle of the embodiment is as follows:

when the blast cap is arranged on the air distribution plate, the air outlet 12 faces to the direction of the slag discharge pipe, when the boiler normally operates, primary air flows upwards from the air chamber through the lower end of the blast cap connecting pipe 2, rises to the top of the blast cap connecting pipe, is uniformly sprayed out through the air inlet holes 21 on the periphery of the blast cap connecting pipe 2, enters the inner cavity of the blast cap, then changes the flowing direction from horizontal left, vertical upwards and horizontal right to vertical downwards, and then flows into the hearth from the air outlet 12 in an inclined way; because the air outlet 12 is arranged at the lower part of the right side wall of the hood shell 13, the air outlet 12 in a single direction can enable fluidized bed bottom materials to generate directional flow, and under the combined action of three factors of the flat hood shell, the blowing force of the unidirectional wind of the air outlet of the hood and a fluidized bed surface obliquely arranged towards the slag discharge pipe, when large incombustibles fall on the inclined bed surface, the large incombustibles can slowly move towards the slag discharge port at the lower end along the inclined bed surface by means of the gravity of the large incombustibles, the thrust of the fluidized bed materials and the blowing force of the unidirectional wind of the air outlet of the hood, and finally enter the waist-shaped slag discharge pipe port to smoothly discharge the large incombustibles and large ash residues. When the pressure in the hearth fluctuates suddenly due to sudden change of water content in fuel or the smoke pressure and flow are reduced due to sudden fan vibration and change of boiler load, and smoke flows backwards, the labyrinth air duct design and blocking of the vertical plate 142 of the labyrinth plate 14 can effectively prevent bed materials serving as solid particles from flowing backwards into the air return chamber, and the structural design that the hood connecting pipe 2 extends upwards to the horizontal plate 141 can further prevent the bed materials from flowing backwards into the air return chamber.

Example three:

the hood head of the embodiment is of a rectangular structure, and the size of the rectangular body in the horizontal direction is 140mm multiplied by 140mm and is larger than the size of the rectangular body in the vertical direction by 50mm; each exhaust hood is embedded into the casting material to form a small plane which inclines towards the slag discharge pipe, the included angle beta between the small plane and the horizontal plane is 10 degrees, and each small plane is combined in an equal difference mode to form a stair type step bed surface. The interval between two adjacent blast caps in each blast cap is 160mm, the distance between two adjacent blast caps is 160mm, the height difference is 92mm, and the included angle between the whole structure of the fluidized bed surface and the horizontal plane is 30 degrees. The rest of the structure is the same as that of the first embodiment, and is not described again.

Example four:

the hood head of the embodiment is of a rectangular structure, and the size of the rectangular body in the horizontal direction is 140mm multiplied by 140mm and is larger than the size of the rectangular body in the vertical direction by 50mm; each exhaust cap is embedded into the casting material to form a small plane which inclines towards the slag discharge pipe, the included angle beta between the small plane and the horizontal plane is 8 degrees, and each small plane is combined in an equal difference mode to form a stair type step bed surface. The interval between two adjacent blast caps in each blast cap is 160mm, the distance between two adjacent blast caps is 340mm, the height difference is 60mm, and the included angle between the whole structure of the fluidized bed surface and the horizontal plane is 10 degrees. The rest of the structure is the same as that of the first embodiment, and is not described again.

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

Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "coupled" are to be construed broadly and encompass, for example, both fixed and removable coupling as well as integral coupling; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In addition to the technical features described in the specification, the technology is known to those skilled in the art.

The above-mentioned embodiments are only for understanding the present invention, and are not intended to limit the technical solutions of the present invention, and those skilled in the relevant art can make various changes or modifications based on the technical solutions described in the claims, and all equivalent changes or modifications should be covered by the scope of the claims of the present invention.

Claims (10)

1. A hidden hood type multi-stage circulating fluidized bed surface structure comprises an air chamber, a water-cooling air distribution plate, a slag discharge pipe and a plurality of hoods arranged on the water-cooling air distribution plate, wherein the top wall of the air chamber is the water-cooling air distribution plate; the blast cap include that blast cap head and blast cap are taken over, the blast cap head sets up in the upper end that the blast cap was taken over, the lower extreme that the blast cap was taken over is vertical to be installed on water-cooling grid plate and to be linked together its characterized in that with the plenum: the blast caps are sequentially reduced from the edge of the hearth to the height of the slag discharge pipe and are arranged in a step shape; the fluidized bed surface is in a step shape corresponding to the blast cap, is built by wear-resistant castable, is embedded in the wear-resistant castable, and is inclined from the edge of the hearth to the slag discharge pipe; the size of the blast cap head in the horizontal direction is larger than that in the vertical direction; the blast cap head is only provided with an air outlet on one side facing the slag discharge pipe.

2. The hidden hood type multi-stage circulating fluidized bed deck structure of claim 1, wherein: the height difference of two rows of adjacent blast caps is arranged according to equal difference, the height difference is determined by the length of the blast cap connecting pipe, the whole fluidized bed surface inclines from the edge of the hearth to the slag discharging pipe, and the included angle between the whole structure of the fluidized bed surface and the horizontal plane is 10-30 degrees; the section of the slag discharge pipe is waist-round.

3. The hidden hood type multi-stage circulating fluidized bed deck structure of claim 2, wherein: each exhaust hood is embedded into the casting material to form a small plane which inclines towards the slag discharge pipe, the included angle between the small plane and the horizontal plane is 5-10 degrees, and each small plane is combined in an equal difference mode to form a stair type step bed surface.

4. The hidden hood type multi-stage circulating fluidized bed deck structure of claim 1, 2 or 3, wherein: the wind cap head comprises a wind cap shell and a labyrinth plate, the wind cap shell is a rectangular cylinder with an opening at the lower end, and the lower part of the right side wall of the wind cap shell is provided with at least 2 air outlet holes; the opening end of the blast cap shell is connected with a sealing plate, so that the blast cap shell forms a sealed inner cavity, the upper end of a blast cap connecting pipe penetrates through the sealing plate to be communicated with the inner cavity of the blast cap shell, and the lower end of the blast cap connecting pipe penetrates through an air distribution plate to be communicated with an air chamber; the labyrinth plate is positioned in the inner cavity of the air cap shell, the inner cavity is divided into a labyrinth air channel, the air cap connecting pipe is communicated with one end of the air channel, and the air outlet hole is communicated with the other end of the air channel.

5. The hidden hood type multi-stage circulating fluidized bed deck structure as claimed in claim 4, wherein: the axes of the air outlet holes are inclined downwards along the air outlet direction, and the included angle between the axes and the horizontal plane is 5-10 degrees.

6. The hidden hood type multi-stage circulating fluidized bed deck structure as claimed in claim 5, wherein: the total sectional area of the air outlet holes is smaller than that of the air inlet pipe.

7. The hidden hood type multi-stage circulating fluidized bed deck structure of claim 4, wherein: the size of the hood shell in the horizontal direction is larger than that in the vertical direction.

8. The hidden hood type multi-stage circulating fluidized bed deck structure as claimed in claim 4, wherein: the labyrinth plate is the shape of falling L, constitute by mutually perpendicular's horizontal plate and riser, the front end of labyrinth plate, the rear end respectively with the preceding lateral wall of hood shell, the back lateral wall links to each other and seals, the horizontal plate, form first wind channel between riser and the closing plate, the left side wall of horizontal plate and hood shell, go up and form second wind channel and third wind channel between the lateral wall, the riser is close to the right side wall of hood shell, lower extreme and closing plate butt and seal, form the fourth wind channel between riser and the right side wall, first wind channel, the second wind channel, the third wind channel, the fourth wind channel has been linked together and has been constituteed the labyrinth wind channel each other.

9. The hidden hood type multi-stage circulating fluidized bed deck structure as claimed in claim 8, wherein: the height of the air outlet is lower than that of the horizontal plate.

10. The hidden hood type multi-stage circulating fluidized bed deck structure as claimed in claim 8, wherein: the blast cap connecting pipe extends upwards to the horizontal plate and is sealed with the horizontal plate, and a plurality of air inlet holes uniformly distributed along the circumference of the blast cap connecting pipe are formed in the side surface of the upper part of the blast cap connecting pipe.

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