CN113503560B

CN113503560B - Flue gas waste heat recovery utilizes device for boiler

Info

Publication number: CN113503560B
Application number: CN202111052279.4A
Authority: CN
Inventors: 吴洋
Original assignee: Nantong Hongyao Boiler Auxiliary Equipment Co ltd
Current assignee: Nantong Hongyao Boiler Auxiliary Equipment Co ltd
Priority date: 2021-09-09
Filing date: 2021-09-09
Publication date: 2021-12-03
Anticipated expiration: 2041-09-09
Also published as: CN113503560A

Abstract

The invention discloses a flue gas waste heat recycling device for a boiler, which comprises a base, wherein the upper surface of the base is fixedly connected with an ash removing cylinder through a support, the upper surface of the ash removing cylinder is fixedly connected with a preheating box, the top wall of the preheating box penetrates through and is fixedly connected with a smoke exhaust cylinder, the bottom wall of the preheating box is provided with a through hole, the top wall of the ash removing cylinder penetrates through and is rotatably connected with a rotating cylinder through a bearing, one end of the rotating cylinder, which is positioned in the through hole, is rotatably connected with a plurality of rotating rods through the bearing, the rotating rods are in interference fit with a sub gear, the sub gear is commonly meshed with a male gear, and the male gear is in interference fit with a rotating shaft. Has the advantages that: compared with the prior art, the flue gas is pretreated firstly, so that the flue gas can be directly contacted with coal, the coal is continuously stirred, the coal can fully absorb the waste heat in the flue gas, the waste heat utilization rate is better, meanwhile, the corrosion of condensed water to the smoke exhaust pipe can be avoided, and the service life of the device is prolonged.

Description

Flue gas waste heat recovery utilizes device for boiler

Technical Field

The invention relates to the technical field of industrial boilers, in particular to a flue gas waste heat recycling device for a boiler.

Background

Industrial boilers are common thermal equipment, generally, coal is used as a combustion raw material, the coal is combusted, combustion heat is used for heating water or other liquid, so that steam is generated and used for power generation or gas supply, the combustion of the coal can generate a lot of flue gas, a large amount of harmful gas exists in the flue gas, a large amount of heat is carried, and direct discharge not only can cause air pollution, but also can cause energy waste.

The existing invention patent, such as a chinese patent with application patent number CN201611216917.0, discloses a flue gas waste heat recycling device for an industrial boiler, which mainly comprises a base, a coal drying box, a coaming, a movable cover body, coal, side plates, a rotating rod, a gear transmission group, etc., wherein the coal is preheated by flue gas waste heat, and harmful substances are filtered by a filter screen, so that the coal can be dried and preheated by flue gas waste heat in the boiler, thereby improving the combustion efficiency of the coal, and the practicability is strong.

Among this technical scheme, the flue gas can't be with coal direct contact, and its preheating effect is general, and only relies on the rotation of stoving case can't fully preheat coal, and if direct make flue gas and coal contact, the fly ash in the flue gas can the adhesion on the coal surface again, influences the coal burning.

Disclosure of Invention

The invention aims to solve the problems of insufficient coal preheating, low preheating utilization rate and the like in the prior art, and provides a flue gas waste heat recycling device for a boiler.

In order to achieve the purpose, the invention adopts the following technical scheme:

a flue gas waste heat recycling device for a boiler comprises a base, wherein the upper surface of the base is fixedly connected with an ash removing cylinder through a bracket, the upper surface of the ash removing cylinder is fixedly connected with a preheating box, the top wall of the preheating box is fixedly connected with a smoke exhaust cylinder in a penetrating way, the bottom wall of the preheating box is provided with a through hole, the top wall of the ash removing cylinder is in penetrating and rotating connection with a rotating cylinder through a bearing, one end of the rotating cylinder, which is positioned in the through hole, is rotatably connected with a plurality of rotating rods through bearings, the rotating rods are in interference fit with sub-gears, the sub-gears are engaged with a father gear which is in interference fit with a rotating shaft, the inner bottom wall of the preheating box is fixedly connected with a gear ring, the sub-gear is meshed with the gear ring together, the rotating rod is located in a section of the stirring blades fixedly connected with the preheating box, and the rotating cylinder is located in a section of the side wall of the ash removing cylinder.

Further, base upper surface fixedly connected with boiler, negative-pressure air fan, fixedly connected with flue gas pipe between boiler and the negative-pressure air fan, negative-pressure air fan's output fixedly connected with intake pipe, the inlet port has been seted up to ash removal barrel lateral wall, the one end that negative-pressure air fan was kept away from to the intake pipe is passed through the inlet port runs through and extends to in the ash removal barrel.

Further, the chimney inside wall is provided with the mechanism of scraping water that is used for striking off the comdenstion water, it includes the sliding tray of seting up at the chimney inside wall to scrape water the mechanism, sliding tray sliding connection has a plurality of sliders, fixed surface is connected with the water conservancy diversion piece on the slider, the guiding gutter has been seted up in the water conservancy diversion piece, fixed surface is connected with the scraper blade on the water conservancy diversion piece, the scraper blade offsets with the chimney inside wall.

Furthermore, the inner side wall of the smoke exhaust cylinder is fixedly connected with a first filter screen and a second filter screen.

Further, a drainage mechanism for discharging condensed water is arranged in the smoke exhaust cylinder, the drainage mechanism comprises a fixed block, a plurality of fixed rods are fixedly connected to the upper surface of the fixed block, one ends of the fixed rods, far away from the fixed block, are fixedly connected with the lower surface of the first filter screen, a water storage tank is arranged on the upper surface of the fixed block, a sliding sleeve is fixedly connected to the upper surface of the fixed block, a plurality of water inlet pipes are fixedly connected in the fixed block in a penetrating manner, one ends of the water inlet pipes extend into the water storage tank in a penetrating manner, the other ends of the water inlet pipes extend into the sliding sleeve in a penetrating manner, a piston is sleeved in the sliding sleeve in a sealing and sliding manner, the piston is in threaded connection with a reciprocating lead screw, the reciprocating lead screw is in penetrating and rotating connection with the fixed block through a bearing, one end, located outside the sliding sleeve and the fixed block, is fixedly connected with the rotating shaft, and a drainage pipe is fixedly connected with the side wall of the sliding sleeve, one end of the drain pipe, which is far away from the sliding sleeve, penetrates through the smoke exhaust cylinder and extends to the outside of the smoke exhaust cylinder.

Further, the diapire rotates through the bearing in the preheating cabinet and is connected with the cage, the cross-section of cage is the character cut in bas-relief shape that the opening is down, the embedded screen cloth that is equipped with of cage top wall, dwang, pivot all through the bearing with the cage through rotation is connected.

Furthermore, the water inlet pipe and the water discharge pipe are both provided with one-way valves.

Further, the scraper blade is made of polytetrafluoroethylene materials, and a hydrophobic coating is coated on the surface of the scraper blade.

Further, the upper surface of the base is provided with an ash receiving box, and the side wall of the preheating box is provided with an article taking opening.

The invention has the following advantages:

1. through the meshing of the sub gear, the father gear and the gear ring, the sub gear rotates around the father gear, and simultaneously rotates, so that the rotating rod rotates around the father gear and also rotates, the stirring blades revolve and rotate along with the rotating rod, and coal in the preheating box is continuously stirred, so that smoke is more fully contacted with the coal, and the coal is dried and preheated by more fully utilizing waste heat;

2. through the arrangement of the ash removing cylinder, fly ash and large-particle impurities in the flue gas are removed, so that the flue gas can be directly contacted with coal, drying and preheating are better performed, and the condition that the direct contact fly ash is adhered to the surface of the coal to influence the subsequent combustion of the coal is avoided;

3. the water scraping mechanism is driven to rotate by the rotation of the rotating rod around the male gear, and condensed water on the inner side wall of the smoke exhaust tube is scraped and collected, so that the condensed water with harmful gas is prevented from corroding the inner side wall of the smoke exhaust tube, the inner side wall of the smoke exhaust tube is prevented from rusting and corroding, and the service life of the device is greatly prolonged;

4. through the arrangement of the drainage mechanism, the water scraped and collected can be drained to the outside of the device, so that the scraped water is prevented from being continuously accumulated in the drainage pipe and being evaporated again;

5. through getting rid of in advance flying dust and large granule debris in the flue gas, effectually avoided large granule debris to block up the filter screen to make better filtering harmful substance of filter screen, also avoided the loaded down with trivial details operation of blockking up clean filter screen simultaneously.

Drawings

FIG. 1 is a schematic view of an appearance of a flue gas waste heat recovery device for a boiler according to the present invention;

FIG. 2 is a schematic structural diagram of a flue gas waste heat recovery device for a boiler according to the present invention;

FIG. 3 is an enlarged view taken at A in FIG. 2;

FIG. 4 is an enlarged view of FIG. 2 at B;

FIG. 5 is an enlarged view at C in FIG. 2;

FIG. 6 is a cross-sectional view of a flue gas waste heat recovery device for a boiler according to the present invention;

FIG. 7 is a cross-sectional view of another part of the flue gas waste heat recovery and utilization device for a boiler according to the present invention;

FIG. 8 is a schematic structural diagram of the interior of a preheating box and a smoke exhaust pipe of the flue gas waste heat recovery and utilization device for a boiler provided by the invention;

fig. 9 is a schematic structural diagram of a wiper mechanism of the flue gas waste heat recycling device for a boiler according to the present invention.

Detailed Description

Referring to fig. 1-9, a flue gas waste heat recycling device for a boiler comprises a base 1, wherein an ash removing cylinder 2 is fixedly connected to the upper surface of the base 1 through a bracket, as shown in fig. 1 and 2, the upper part of the ash removing cylinder 2 is cylindrical, and the lower part of the ash removing cylinder 2 is truncated cone-shaped, so that flue gas with fly ash enters the ash removing cylinder 2, the flue gas can rotate from top to bottom along the inner side wall of the ash removing cylinder 2, large-particle impurities such as fly ash are tightly attached to the inner side wall of the ash removing cylinder 2 under the action of centrifugal force and fall down, the flue gas after pre-dedusting can be discharged into a preheating tank 3 through a rotating cylinder 201 upwards along the central line of the ash removing cylinder 2 in a swirling manner, so that the flue gas is pretreated, the fly ash in the flue gas is removed, the flue gas can be directly contacted with coal, the coal is dried and preheated, meanwhile, the filter screen is prevented from being blocked by the large-particle impurities, and a preheating tank 3 is fixedly connected to the upper surface of the ash removing cylinder 2, the top wall of the preheating box 3 is fixedly connected with a smoke exhaust tube 4 in a penetrating way, the bottom wall of the preheating box 3 is provided with a through hole 301, the top wall of the ash removing tube 2 is rotatably connected with a rotating tube 201 in a penetrating way through a bearing, one end of the rotating tube 201 positioned in the through hole 301 is rotatably connected with a plurality of rotating rods 302 through a bearing, the rotating rods 302 are in interference fit with a sub gear 303, the sub gear 303 is meshed with a parent gear 304 together, the parent gear 304 is in interference fit with a rotating shaft 305, the bottom wall of the preheating box 3 is fixedly connected with a gear ring 306, the sub gear 303 is meshed with the gear ring 306 together, one section of the rotating rods 302 positioned in the preheating box 3 is fixedly connected with a plurality of stirring blades 307, the sub gear 303 rotates around the parent gear 304 while rotating, the rotating rods 302 rotate around the parent gear 304, the stirring blades 307 revolve and rotate together with the rotating rods 302, and coal in the preheating box 3 is continuously stirred, thereby make the flue gas more abundant with the coal contact, more abundant utilization waste heat is dried, is preheated coal, as shown in fig. 2, fig. 7 and fig. 8, stirring vane 307 on each dwang 302 distributes in proper order from top to bottom to make stirring vane 307 can stir the coal on different layers, a plurality of fins 202 of lateral wall fixedly connected with that section inside the rotary cylinder 201 is located ash removing cylinder 2, the setting of fin 202 can make the flue gas drive rotary cylinder 201 and rotate.

Referring to fig. 1 and 6, fixed surface is connected with boiler 101 on base 1, negative-pressure air fan 103, fixedly connected with flue gas pipe 102 between boiler 101 and the negative-pressure air fan 103, negative-pressure air fan 103's output fixedly connected with intake pipe 104, negative-pressure air fan 103 should adopt and compare in the more powerful fan of prior art, thereby make a part of energy that the flue gas blows can drive and rotate section of thick bamboo 201 and rotate, inlet port 203 has been seted up to dusting section of thick bamboo 2 lateral wall, the one end that negative-pressure air fan 103 was kept away from to intake pipe 104 runs through in extending to dusting section of thick bamboo 2 through inlet port 203, intake pipe 104 biasing gets into in dusting section of thick bamboo 2, thereby make the flue gas blow fin 202, make to rotate section of thick bamboo 201 and rotate, get into dusting section of thick bamboo 2 simultaneously along the tangential of dusting section of thick bamboo 2 inside wall motion of dusting section of thick bamboo 2, make flue gas and flying dust move along the inside wall of dusting section of thick bamboo 2.

Referring to fig. 2-5 and 8-9, a water scraping mechanism for scraping off condensed water is disposed on an inner side wall of the exhaust funnel 4, the water scraping mechanism includes a sliding groove 401 disposed on an inner side wall of the exhaust funnel 4, the sliding groove 401 is an annular sliding groove disposed along the inner side wall of the exhaust funnel 4, the cross section of the sliding groove is T-shaped, a plurality of sliders 402 are slidably connected in the sliding groove 401, an interface of the sliders 402 is also T-shaped and extends out of a section of the sliding groove 401, a flow guide block 403 is fixedly connected to an upper surface of the slider 402, the flow guide block 403 is fixedly connected to an upper surface of a section of the slider 402 extending out of the sliding groove 401, a flow guide groove 404 is disposed in the flow guide block 403, a scraper 405 is fixedly connected to an upper surface of the flow guide block 403, the scraper 405 abuts against the inner side wall of the exhaust funnel 4, the flow guide block 403 abuts against a corresponding rotating rod 302, so as to be pushed to move along the direction of the sliding groove 401 by the rotation of the rotating rod 302, the flow guide block 403 is disposed obliquely, its bottom directly extends to in the aqua storage tank 601 to make the water of scraping down directly flow in the aqua storage tank 601 along with guiding groove 404, because contain certain vapor in the flue gas, consequently easily meet cold emergence condensation in the 4 inside wall departments of chimney, contain harmful substance such as sulfur dioxide in its comdenstion water, have stronger corrosivity to 4 inside walls of chimney, can lead to the corrosion of chimney for a long time, seriously influence the device life-span, strike off the comdenstion water through scraping water mechanism, the life of chimney has been improved greatly.

Scraper blade 405 is made for the polytetrafluoroethylene material, and polytetrafluoroethylene is bigger in lighter intensity when scraper blade 405 texture that is working, and corrosion-resistant, can effectually tolerate harsh environment in chimney 4, and scraper blade 405 surface is scribbled and is equipped with hydrophobic coating, and hydrophobic coating can be so that the water of scraping down can not the adhesion on scraper blade 405, but directly falls into in guiding gutter 404.

The inner side wall of the exhaust funnel 4 is fixedly connected with a first filter screen 406 and a second filter screen 407.

Referring to fig. 2-4 and 8, a drainage mechanism for discharging condensed water is disposed in the chimney 4, the drainage mechanism includes a fixed block 6, the fixed block 6 is disc-shaped, a plurality of fixing rods 607 are fixedly connected to the upper surface of the fixed block 6, one end of each fixing rod 607 far from the fixed block 6 is fixedly connected to the lower surface of the first filter 406, a water storage tank 601 is disposed on the upper surface of the fixed block 6, the water storage tank 601 is an annular groove, a sliding sleeve 602 is fixedly connected to the upper surface of the fixed block 6, the cross section of the sliding sleeve 602 is in a shape of a Chinese character 'ao' with an upward opening, the bottom end of the sliding sleeve is closed, the top end of the sliding sleeve is open, a plurality of water inlet pipes 603 are fixedly connected to the inside of the fixed block 6, one end of each water inlet pipe 603 extends into the water storage tank 601, the other end extends into the sliding sleeve 602, a piston 605 is hermetically and slidably sleeved inside the sliding sleeve 602, the inner side wall of the sliding sleeve 602 has a smaller irregularity degree, which is not shown in the figure, so that the piston 605 can only reciprocate up and down under the rotation of the reciprocating lead screw 606 and can not rotate relative to the sliding sleeve 602, the piston 605 is connected with the reciprocating lead screw 606 by screw thread, the threaded connection between the reciprocating lead screw 606 and the piston 605 is provided with a sealing gasket to avoid the leakage of the threaded connection, the reciprocating lead screw 606 is connected with the fixed block 6 by a bearing in a penetrating and rotating way, one end of the reciprocating lead screw 606 positioned outside the sliding sleeve 602 and the fixed block 6 is fixedly connected with the rotating shaft 305, the side wall of the sliding sleeve 602 is fixedly connected with a drain pipe 604 by penetrating, one end of the drain pipe 604 far away from the sliding sleeve 602 penetrates through the smoke exhaust tube 4 and extends to the outside, the piston 605 is driven by the reciprocating lead screw 606 to reciprocate up and down, when moving up, the water in the water storage tank 601 is pumped into the sliding sleeve 602, when moving down, the water in the sliding sleeve 602 is pumped out through the drain pipe 604, one end of the drain pipe 604 positioned outside is connected with the water storage device, the wastewater is recycled, so that the scraped condensate water is prevented from being continuously stored in the smoke exhaust tube 4 and being continuously evaporated and then condensed;

one-way valves (not shown) are arranged in the water inlet pipe 603 and the water outlet pipe 604, the one-way valve in the water inlet pipe 603 only allows water to enter the sliding sleeve 602 from the water storage tank 601, and the one-way valve in the water outlet pipe 604 only allows water to enter the water outlet pipe 604 from the sliding sleeve 602, so that the up-and-down movement of the piston 605 pumps the water in the water storage tank 601 into the water outlet pipe 604 and discharges the water to the outside.

Referring to fig. 2 and 7, the bottom wall rotates through the bearing in the preheating cabinet 3 and is connected with cage 5, the cross-section of cage 5 is the shape of character cut in bas-relief that the opening is down, the embedded screen cloth 501 that is equipped with of cage 5 roof, dwang 302, pivot 305 all runs through rotation with cage 5 through the bearing and is connected, the annular opening has been seted up to cage 5, the annular opening divides cage 5 into two parts, screen cloth 501 inlays to be established in the annular opening, link together two parts of cage 5, thereby block upper portion coal, avoid it to fall into in the ash removal section of thick bamboo 2 of below.

The upper surface of the base 1 is provided with an ash receiving box 105, and the side wall of the preheating box 3 is provided with an article taking opening 308.

In the invention, coal to be preheated is placed in a preheating box 3 through a fetching opening 308, smoke in a boiler 101 is pumped into an ash removing cylinder 2 through a smoke pipe 102 and an air inlet pipe 104 in a biased mode at a certain speed by a negative pressure fan 103, the smoke impacts a fin 202 to enable the rotating cylinder 201 to rotate, meanwhile, the smoke with fly ash is pumped into the ash removing cylinder 2 along the tangential direction of the inner side wall of the ash removing cylinder 2, the smoke can rotate from top to bottom along the inner side wall of the ash removing cylinder 2, large-particle impurities such as fly ash cling to the inner side wall of the ash removing cylinder 2 under the action of centrifugal force and fall down under the action of self gravity, the smoke falls into an ash receiving box 105 below, and the smoke after pre-dedusting can upwards swirl along the central line of the ash removing cylinder 2 and is discharged into the preheating box 3 through the rotating cylinder 201, so that the smoke is pretreated, the fly ash in the smoke is removed, and the smoke can be directly contacted with the coal;

when the flue gas of dust removal in advance contacts with coal, a section of thick bamboo 201 rotates, it drives dwang 302 and drives the sub-gear 303 of its interference fit together and rotate around father gear 304, through father gear 304, sub-gear 303, the meshing of ring gear 306, make sub-gear 303 around father gear 304 pivoted simultaneously, self takes place to rotate, thereby it rotates to drive dwang 302 around father gear 304 pivoted simultaneously, self takes place to change, thereby constantly stir the coal in preheating cabinet 3 through stirring vane 307 on dwang 302, make its better contact with the flue gas, the preheating of more effectual utilization flue gas is dried coal, preheat.

The flue gas after the waste heat utilization is discharged to the outside after being filtered by a first filter screen 406 and a second filter screen 407 in the smoke exhaust tube 4;

meanwhile, the rotation of the rotating rod 302 can also push the guide block 403 to move along the arrangement direction of the sliding groove 401, so that the scraper plate 405 on the guide block 403 moves along the inner side wall of the exhaust pipe 4, condensed water condensed on the inner side wall of the exhaust pipe 4 is scraped, and then flows into the guide groove 404 along the scraper plate 405 and flows into the water storage groove 601 along the guide groove 404, and therefore the exhaust pipe 4 is prevented from being corroded by the condensed water;

when the condensed water flows into the water storage tank 601, the male gear 304 drives the rotating shaft 305 to rotate, so that the rotating shaft 305 drives the reciprocating screw 606 to rotate, so that the piston 605 reciprocates up and down, when the piston 605 moves up, the water in the water storage tank 601 is pumped into the sliding sleeve 602 through the water inlet pipe 603, and when the piston 605 moves down, the water sucked into the sliding sleeve 602 is pumped out of the sliding sleeve 602 through the water outlet pipe 604, so that the scraped condensed water is prevented from being accumulated in the smoke exhaust tube 4 and continuing to evaporate and condense;

and after preheating is finished, taking out the preheated coal in the preheating box 3, adding the coal into the boiler 101, and putting the coal to be preheated again.

Claims

1. The utility model provides a flue gas waste heat recovery utilizes device for boiler, includes base (1), its characterized in that, install ash removal section of thick bamboo (2) on base (1), ash removal section of thick bamboo (2) lateral wall has seted up inlet port (203), install preheating cabinet (3) on ash removal section of thick bamboo (2), preheating cabinet (3) lateral wall has been seted up and has been got thing mouth (308), preheating cabinet (3) are connected with exhaust stack (4), through-hole (301) have been seted up to preheating cabinet (3) diapire, ash removal section of thick bamboo (2) roof runs through the rotation through the bearing and is connected with rotary drum (201), and the one end that rotary drum (201) is located through-hole (301) is connected with a plurality of dwang (302) through the bearing rotation, dwang (302) interference fit has pinion (303), pinion (303) mesh has father gear (304) jointly, father gear (304) interference fit has pivot (305), the inner bottom wall of the preheating box (3) is fixedly connected with a gear ring (306), the sub-gears (303) are jointly meshed with the gear ring (306), the rotating rod (302) is connected with a plurality of stirring blades (307), and the side wall of the rotating cylinder (201) is fixedly connected with a plurality of fins (202);

a drainage mechanism for discharging condensed water is arranged in the smoke exhaust tube (4), the drainage mechanism comprises a fixed block (6), the upper surface of the fixed block (6) is fixedly connected with a plurality of fixing rods (607), the upper surface of the fixed block (6) is provided with a water storage tank (601), the upper surface of the fixed block (6) is fixedly connected with a sliding sleeve (602), the fixed block (6) is internally and fixedly connected with a plurality of water inlet tubes (603) in a penetrating manner, one end of each water inlet tube (603) penetrates and extends into the water storage tank (601), the other end penetrates and extends into the sliding sleeve (602), a piston (605) is sleeved in the sliding sleeve (602) in a sealing and sliding manner, the piston (605) is in threaded connection with a reciprocating lead screw (606), the lower end of the reciprocating lead screw (606) penetrates through the sliding sleeve (602) and the fixed block (6) and is fixedly connected with a rotating shaft (305), and the side wall of the sliding sleeve (602) penetrates and is fixedly connected with a drain pipe (604), one end that sliding sleeve (602) was kept away from in drain pipe (604) runs through exhaust pipe (4) and extend to its outside, exhaust pipe (4) inside wall is provided with the mechanism of scraping water that is used for striking off the comdenstion water, it includes sliding tray (401) of seting up at exhaust pipe (4) inside wall to scrape the mechanism, sliding tray (401) sliding connection has a plurality of sliders (402), fixed surface is connected with water conservancy diversion piece (403) on slider (402), water conservancy diversion groove (404) have been seted up in water conservancy diversion piece (403), water conservancy diversion piece (403) slope sets up, and its bottom directly extends to in aqua storage tank (601), fixed surface is connected with scraper blade (405) on water conservancy diversion piece (403), scraper blade (405) offset with exhaust pipe (4) inside wall.

2. The flue gas waste heat recycling device for the boiler according to claim 1, characterized in that a boiler (101) and a negative pressure fan (103) are fixedly connected to the upper surface of the base (1), a flue gas pipe (102) is fixedly connected between the boiler (101) and the negative pressure fan (103), an air inlet pipe (104) is fixedly connected to the output end of the negative pressure fan (103), and one end, far away from the negative pressure fan (103), of the air inlet pipe (104) penetrates through the air inlet hole (203) and extends into the ash removing cylinder (2).

3. The flue gas waste heat recycling device for the boiler as claimed in claim 1, wherein the inner side wall of the exhaust pipe (4) is fixedly connected with a first filter screen (406) and a second filter screen (407), and one end of the fixing rod (607) far away from the fixing block (6) is fixedly connected with the lower surface of the first filter screen (406).

4. The device for recycling the waste heat of the flue gas for the boiler according to claim 1, wherein a shielding case (5) is rotatably connected to the inner bottom wall of the preheating box (3) through a bearing, the cross section of the shielding case (5) is a concave shape with a downward opening, a screen (501) is embedded in the top wall of the shielding case (5), and the rotating rod (302) and the rotating shaft (305) are both rotatably connected with the shielding case (5) through the bearing.

5. The flue gas waste heat recycling device for the boiler according to claim 1, wherein a check valve is disposed in each of the water inlet pipe (603) and the water outlet pipe (604).

6. The device for recycling the waste heat of the flue gas for the boiler as recited in claim 1, wherein said scraper (405) is made of polytetrafluoroethylene, and a hydrophobic coating is coated on the surface of said scraper (405).

7. The flue gas waste heat recycling device for the boiler according to claim 1, characterized in that an ash receiving box (105) is arranged on the upper surface of the base (1).