WNF type internal furnace built-in fluidized combustion biomass steam boiler
By adopting a fluidized bed structure with air caps and spiral air ducts in the fluidized bed boiler, the problems of heat storage and coking caused by quartz sand in the material bed are solved, realizing efficient, compact and environmentally friendly biomass steam boiler combustion.
Patent Information
- Application Number
- CN202511204401.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-27
- Publication Date
- 2025-12-09
AI Technical Summary
Conventional fluidized bed boilers use quartz sand as the fluidizing medium, which increases the risk of heat storage and coking in the bed, wears down the heating surface, increases the air pressure and power of the fluidizing fan, increases power consumption, and makes the boiler size less compact.
The fluidized bed mechanism with air vents enables low-ratio fluidized combustion, reduces heat storage in the material bed, prevents coking, reduces wear, and lowers fan power consumption. By setting up the fluidized bed mechanism, the material bed is blown up by the air vents, and in conjunction with the spiral air duct and dispersing rod, uniform distribution and efficient combustion of biomass pellets are achieved.
Improve combustion efficiency, reduce power consumption, reduce wear, enhance boiler structural compactness, reduce maintenance costs, and achieve efficient ash removal and low nitrogen oxide emissions.
Smart Images
Figure CN121089031A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of steam boilers, more particularly to a WNF type furnace built-in fluidized combustion biomass steam boiler. BACKGROUND
[0002] The WNF type furnace built-in fluidized combustion biomass steam boiler is a boiler designed specifically for efficient combustion of biomass fuel (such as wood chips, straw, etc.) to generate steam. This boiler uses advanced fluidized bed combustion technology, by injecting air or other gas media into the combustion chamber containing granular fuel and sand or other inert materials, making these materials suspended and moving violently, forming a liquid-like state, thus achieving efficient and clean combustion process.
[0003] Conventional fluidized bed boilers use quartz sand as fluidizing medium, which increases the risk of material layer heat storage and coking, and causes wear to the boiler heating surface. In addition, the use of quartz sand increases the material layer resistance, resulting in the need for higher fluidized fan pressure and power, increasing power consumption, and increasing the height of the dense phase zone, making the overall size of the boiler not compact enough, which affects the efficiency and maintenance cost of the boiler. SUMMARY
[0004] In view of the problems existing in the prior art, the purpose of the present application is to provide a WNF type furnace built-in fluidized combustion biomass steam boiler, which can realize low ratio fluidized combustion, reduce material layer heat storage and prevent material layer coking.
[0005] To solve the above problems, the present application adopts the following technical scheme.
[0006] A WNF type furnace built-in fluidized combustion biomass steam boiler, comprising a base, a housing fixedly installed on the upper end face of the base, a flat furnace installed fixedly in the housing, a fluidized bed mechanism provided in the interior of the flat furnace, the fluidized bed mechanism comprising a wind distribution plate fixedly installed in the interior of the flat furnace, a fire wall fixedly installed on the right end face of the wind distribution plate, a plurality of air caps provided on the wind distribution plate, a feed pipe fixedly installed on the left end face of the housing, one end of the feed pipe extending into the interior of the flat furnace and fixedly connected with the wind distribution plate, a dispersion pipe provided on the upper side of the wind distribution plate, the dispersion pipe penetrating through the wind distribution plate and screw-fixedly connected with the feed pipe, and a spiral air duct fixedly installed at the end of the dispersion pipe.
[0007] A material bin is provided on the left side of the housing, a screw feeder is communicated with the lower end face of the material bin, a fan one and a fan two are provided on the lower side of the screw feeder, the screw feeder and the fan one are in communication with the feed pipe, the fan two and the feed pipe are in communication with the flat furnace, and are provided on the lower side of the wind distribution plate.
[0008] The outer surface of the shell is provided with a valve, the left end surface of the shell is provided with a ignition hole corresponding to the flat stove pipe, the right end of the flat stove pipe is provided with a corrugated stove pipe in communication, the right end surface of the corrugated stove pipe is provided with a back combustion chamber in communication, the lower end surface of the back combustion chamber is provided with a ash falling pipe in communication, and the ash falling pipe extends to the outside of the shell.
[0009] The right end surface of the shell is provided with an inspection hole, the inside left side of the shell is fixedly installed with a front smoke box, a plurality of groups of first return smoke pipes are provided in communication between the front smoke box and the back combustion chamber, and the right end surface of the shell is fixedly installed with a rear smoke box.
[0010] A plurality of groups of second return smoke pipes are provided in communication between the rear smoke box and the front smoke box, the outer surface of the rear smoke box is provided with a connecting flue in communication, the connecting flue and the external energy saver are in communication with each other, and a plurality of groups of main steam valves are provided on the upper side of the outer surface of the shell in communication.
[0011] The fluidized bed mechanism further comprises a crushing piece arranged in the dispersion pipe, the crushing piece further comprises a groove one opened in the inner wall of the dispersion pipe, a rotating ring one is rotatably connected in the inner part of the groove one, and a plurality of groups of spiral blades are fixedly installed on the inner wall of the rotating ring one.
[0012] A gear ring one is fixedly installed on the upper end surface of the rotating ring one, an inner cavity is opened in the inner part of the air distribution plate, a rotating shaft is arranged in the inner cavity, a gear one is fixedly installed on the upper end of the rotating shaft, a slot one is opened between the inner cavity and the groove one, and the gear one is engaged with the gear ring one through the slot one.
[0013] A groove two is opened in the inner wall of the feeding pipe, a rotating ring two is rotatably connected in the inner part of the groove two, a gear ring two is fixedly installed on the outer surface of the rotating ring two, a plurality of groups of scattering rods are fixedly installed on the inner wall of the rotating ring two, a slot two is opened on the outer surface of the feeding pipe, the slot two and the groove two are in communication with each other, a gear two is arranged in the inner part of the slot two, the gear two is engaged with the gear ring two, and the lower end of the rotating shaft extends to the outside of the inner cavity and is fixedly connected with the gear two.
[0014] A piston cavity is opened in the inner part of the feeding pipe, a piston rod is slidably connected in the inner part of the piston cavity, a lower pressing plate is fixedly installed on the upper end of the piston rod, the lower pressing plate is arranged on the lower side of the dispersion pipe, and a spring is fixedly installed between the lower pressing plate and the inner wall of the piston cavity.
[0015] A sliding block is sleeved on the outer surface of the rotating shaft, the sliding block is rotatably connected with the rotating shaft, the sliding block is slidably connected with the inner cavity, a limiting cavity is opened in the inner wall of the inner cavity, a limiting rod is slidably connected in the inner part of the limiting cavity, the limiting rod is fixedly connected with the sliding block, and a communication pipe is provided in communication between the limiting cavity and the piston cavity.
[0016] Compared with the prior art, the present application has the following beneficial effects: (1) The present application sets up a fluidized bed mechanism, uses the air cap to blow the material layer to realize low-ratio fluidized combustion, reduces the material layer heat accumulation, prevents the material layer coking, prevents the quartz sand from wearing the boiler heating surface, reduces the material layer resistance, greatly reduces the fluidized fan pressure and power, reduces the fan power consumption, reduces the dense phase zone height, and makes the boiler size more compact. BRIEF DESCRIPTION OF DRAWINGS
[0017] Figure 1 is a schematic diagram of the overall structure of the present application; Figure 2 is a schematic diagram of the overall structure of the present application; Figure 1 is an enlarged schematic diagram of position A in the present application; Figure 3 is a cross-sectional view of the overall structure of the present application; Figure 4 is a schematic diagram of the overall structure of the present application; Figure 3 is an enlarged schematic diagram of position B in the present application; Figure 5 is a schematic diagram of the overall structure of the present application; Figure 4 is an enlarged schematic diagram of position C in the present application; Figure 6 is a schematic diagram of the overall structure of the present application; Figure 4 is an enlarged schematic diagram of position D in the present application; Figure 7 is a schematic diagram of the overall structure of the present application; Figure 4 is an enlarged schematic diagram of position E in the present application.
[0018] REFERENCE NUMERALS IN DRAWINGS: 1, base; 2, outer shell; 3, material bin; 4, screw feeder; 5, fan one; 6, feeding pipe; 7, fan two; 8, flat furnace tube; 9, corrugated furnace tube; 10, ignition port; 11, back-pumping chamber; 12, ash falling pipe; 13, inspection hole; 14, front smoke box; 15, first back-pumping smoke pipe; 16, rear smoke box; 17, second back-pumping smoke pipe; 18, connecting flue; 19, main steam valve; 20, air distribution plate; 21, air cap; 22, dispersion pipe; 23, spiral air duct; 24, groove one; 25, rotating ring one; 26, spiral blade; 27, gear ring one; 28, inner cavity; 29, sliding block; 30, rotating shaft; 31, gear one; 32, gear two; 33, groove two; 34, rotating ring two; 35, dispersing rod; 36, gear ring two; 37, slot one; 38, slot two; 39, piston cavity; 40, piston rod; 41, lower pressing plate; 42, spring; 43, communication pipe; 44, limiting cavity; 45, limiting rod; 46, fireproof wall. DETAILED DESCRIPTION
[0019] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described; obviously, the described embodiments are only a part of the embodiments of the present application, and not all the embodiments; based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present application.
[0020] Please refer to Figures 1 to 7 The WNF type built-in fluidized combustion biomass steam boiler comprises a base 1, an outer shell 2 fixedly installed on the upper end surface of the base 1, a flat stove 8 fixedly installed in the inner part of the outer shell 2, a fluidized bed mechanism arranged in the inner part of the flat stove 8, the fluidized bed mechanism comprising a wind distribution plate 20 fixedly installed in the inner part of the flat stove 8, a fire dam 46 fixedly installed on the right end surface of the wind distribution plate 20, a plurality of groups of air caps 21 arranged on the wind distribution plate 20, a feeding pipe 6 fixedly installed on the left end surface of the outer shell 2, one end of the feeding pipe 6 extending to the inner part of the flat stove 8 and fixedly connected with the wind distribution plate 20, a dispersion pipe 22 arranged on the upper side of the wind distribution plate 20, the dispersion pipe 22 penetrating through the wind distribution plate 20 and spirally fixedly connected with the feeding pipe 6, and a spiral air duct 23 fixedly installed on the end part of the dispersion pipe 22.
[0021] A material bin 3 is arranged on the left side of the outer shell 2, a spiral feeder 4 is arranged in communication with the lower end surface of the material bin 3, a fan one 5 and a fan two 7 are arranged on the lower side of the spiral feeder 4, the spiral feeder 4 and the fan one 5 are in communication with the feeding pipe 6, and the fan two 7 and the feeding pipe 6 are in communication with the flat stove 8 and arranged on the lower side of the wind distribution plate 20.
[0022] A valve is arranged in communication with the outer surface of the outer shell 2, a lighting hole 10 is arranged on the left end surface of the outer shell 2 corresponding to the flat stove 8, a corrugated stove 9 is arranged in communication with the right end of the flat stove 8, a back combustion chamber 11 is arranged in communication with the right end surface of the corrugated stove 9, an ash falling pipe 12 is arranged in communication with the lower end surface of the back combustion chamber 11, and the ash falling pipe 12 extends to the outside of the outer shell 2.
[0023] An inspection hole 13 is arranged in communication with the right end surface of the outer shell 2, a front smoke box 14 is fixedly installed on the inner left side of the outer shell 2, a plurality of groups of first back smoke pipes 15 are arranged in communication between the front smoke box 14 and the back combustion chamber 11, and a rear smoke box 16 is fixedly installed on the right end surface of the outer shell 2.
[0024] The material from the bin 3 is blown by the high-pressure fan of the fan 5 after passing through the screw feeder 4 (adjusting the feeding amount), the outlet of the dispersion pipe 22 is provided with a spiral air duct 23, the biomass particles are blown by the high-pressure air and sprayed in the form of cyclone, and the dispersion pipe 22 is arranged at the center of the air distribution plate 20, the dispersion pipe 22 blows out from the center of the air distribution plate 20, the built-in air distribution plate 20 and the air cap 21 form a fluidized bed mechanism, and are located at the front end of the flat stove pipe 8, the bottom is a wind chamber, the air distribution plate 20 is arranged on the wind chamber, the air cap 21 is arranged on the air distribution plate 20, the air of the fan 7 enters the wind chamber and comes out from the small holes of the air cap 21, the material layer is blown up, the ignition is realized by cooperating with the ignition port 10 to realize the fluidized combustion, the rear end of the air distribution plate 20 is provided with a fireproof wall 46, the upper part of the fireproof wall 46 is a fluidized bed smoke outlet, the fluidized combustion is entered into the corrugated stove pipe 9, then into the back-burning chamber 11, then into the first backstroke smoke pipe 15, through the front smoke box 14, then into the second backstroke smoke pipe 17, through the rear smoke box 16, through the connecting flue 18, into the external energy saver, and the smoke is discharged from the bottom smoke outlet of the energy saver, and the fireproof wall 46 increases the resistance of the flue gas, improves the fluidized circulation ratio, prolongs the residence time of the high-temperature flue gas, improves the heat storage and temperature of the fluidized bed furnace, and improves the combustion efficiency.
[0025] A plurality of second backstroke smoke pipes 17 are arranged in communication between the rear smoke box 16 and the front smoke box 14, the outer surface of the rear smoke box 16 is provided with a connecting flue 18 in communication, the connecting flue 18 and the external energy saver are in communication, and a plurality of main steam valves 19 are arranged in communication on the outer surface of the outer shell 2.
[0026] The fluidized bed mechanism further comprises a crushing part arranged in the dispersion pipe 22, the crushing part further comprises a groove one 24 formed in the inner wall of the dispersion pipe 22, a rotating ring one 25 is rotatably connected in the groove one 24, and a plurality of spiral blades 26 are fixedly installed on the inner wall of the rotating ring one 25.
[0027] A gear ring one 27 is fixedly installed on the upper end surface of the rotating ring one 25, an inner cavity 28 is formed in the inner part of the air distribution plate 20, a rotating shaft 30 is arranged in the inner part of the inner cavity 28, a gear one 31 is fixedly installed on the upper end of the rotating shaft 30, a slot one 37 is formed between the inner cavity 28 and the groove one 24, and the gear one 31 is engaged with the gear ring one 27 through the slot one 37.
[0028] A groove two 33 is formed in the inner wall of the feeding pipe 6, a rotating ring two 34 is rotatably connected in the groove two 33, a gear ring two 36 is fixedly installed on the outer surface of the rotating ring two 34, a plurality of scattering rods 35 are fixedly installed on the inner wall of the rotating ring two 34, a slot two 38 is formed in the outer surface of the feeding pipe 6, the slot two 38 and the groove two 33 are in communication, a gear two 32 is arranged in the inner part of the slot two 38, the gear two 32 is engaged with the gear ring two 36, and the lower end of the rotating shaft 30 extends to the outer side of the inner cavity 28 and is fixedly connected with the gear two 32.
[0029] The feed pipe 6 has a piston chamber 39 inside, and a piston rod 40 is slidably connected inside the piston chamber 39. A lower pressure plate 41 is fixedly installed at the upper end of the piston rod 40. The lower pressure plate 41 is located on the lower side of the dispersion pipe 22. A spring 42 is fixedly installed between the lower pressure plate 41 and the inner wall of the piston chamber 39.
[0030] A slider 29 is fitted on the outer surface of the rotating shaft 30. The slider 29 is rotatably connected to the rotating shaft 30 and slidably connected to the inner cavity 28. A limiting cavity 44 is opened on the inner wall of the inner cavity 28. A limiting rod 45 is slidably connected inside the limiting cavity 44. The limiting rod 45 is fixedly connected to the slider 29. A connecting pipe 43 is provided between the limiting cavity 44 and the piston cavity 39.
[0031] Secondly, the dispersion tube 22 adopts a quick-release design, which allows for quick installation and disassembly of the dispersion tube 22 and the feed tube 6 through threaded fixing. When the dispersion tube 22 is spirally twisted into the feed tube 6, it will squeeze the lower pressure plate 41, causing the piston rod 40 to insert into the piston chamber 39. This allows the gas inside the piston chamber 39 to be discharged into the limiting chamber 44 through the connecting pipe 43, causing the limiting rod 45 to push the slider 29 to move. This causes the gear 31 on the rotating shaft 30 to mesh with the gear ring 27, and the gear 32 to mesh with the gear ring 36, completing the installation of the crushing parts. When the high-pressure blower of the blower 5 blows the biomass pellets into the dispersion tube 22 through the feed tube 6, since the flow from the feed tube 6 into the dispersion tube 22 is a large pipe to a small pipe, the flow rate will increase when the fluid (liquid or gas) flows from the large pipe diameter to the small pipe diameter. This is due to the continuous flow... The flow rate is determined by both the conservation equation (mass conservation) and Bernoulli's equation (energy conservation). Therefore, when entering the dispersion tube 22, the flow rate will increase and flush the spiral blades 26 inside the rotating ring 25, causing the rotating ring 25 to rotate with the toothed ring 27. The toothed ring 27 meshes with the gear 31 on the rotating shaft 30, so the rotating shaft 30 will rotate with the gear 32. The gear 32 meshes with the toothed ring 36 on the rotating ring 34, thus driving the rotating ring 34 to rotate rapidly and carrying the internal dispersing rod 35 to rotate rapidly. The dispersing rod 35 is located in the feed pipe 6, inside the large pipe, where the flow rate is lower than that in the small pipe. The rotation speed of the dispersing rod 35 is higher than the flow rate inside the feed pipe 6, thus dispersing the incoming biomass pellets and preventing them from clumping together, which would affect the combustion efficiency.
[0032] Conventional fluidized bed boilers use quartz sand as the fluidizing medium, which increases the risk of heat storage and coking in the bed and causes wear on the boiler's heating surfaces. In addition, the use of quartz sand increases bed resistance, requiring higher fluidizing fan pressure and power, increasing power consumption, and increasing the height of the dense phase zone, making the overall boiler size less compact. These problems affect the boiler's efficiency and maintenance costs. Therefore, this solution uses a fluidized bed mechanism and air outlets 21 to blow up the bed to achieve low-ratio fluidized combustion, reducing bed heat storage, preventing bed coking, preventing wear of the boiler's heating surfaces by quartz sand, reducing bed resistance, greatly reducing fluidizing fan pressure and power, reducing fan power consumption, reducing the height of the dense phase zone, and making the boiler size more compact.
[0033] This application features: 1. High combustion efficiency, high thermal efficiency, and energy saving; 2. Compact structure, convenient transportation and installation; 3. Low nitrogen oxide emissions, environmentally friendly; 4. Convenient ash removal, with an ash discharge pipe 12 at the bottom of the combustion chamber 11 and an inspection and ash removal port at the rear of the combustion chamber 11. Both the front smoke box 14 and the rear smoke box 16 can be easily opened for regular ash removal; 5. Three-pass boiler flue gas circulation, sufficient heating area, and thorough heat exchange; a smoke tube-type energy saver is installed at the tail of the main unit to reduce the exhaust temperature and achieve high thermal efficiency; 6. The application uses a corrugated furnace liner 9 and threaded smoke tubes with high-efficiency heat exchange surfaces.
[0034] Operating method: The material from the silo 3 passes through the screw feeder 4 (with adjustable feed rate) and is then blown by the high-pressure blower 5. A spiral air duct 23 is installed at the outlet of the dispersion pipe 22. The biomass pellets are ejected in a swirling spray pattern by the high-pressure blower. The dispersion pipe 22 is located at the center of the air distribution plate 20. The material is blown out from the dispersion pipe 22 at the center of the air distribution plate 20. Simultaneously, the built-in air distribution plate 20 and air cap 21 form a fluidized bed mechanism, located at the front end of the straight furnace 8. The bottom is the air chamber, on which the air distribution plate 20 is mounted. The air cap 21 is installed on the air distribution plate 20. The blower 7 blows air into the air chamber and out through the small holes in the air cap 21. The material layer is blown up and ignited at the ignition port 10 to achieve fluidized combustion. Next, a fire baffle 46 is set at the rear end of the air distribution plate 20. The upper part of the fire baffle 46 is the fluidized bed outlet. After fluidized combustion, the material enters the corrugated furnace liner 9, then the combustion chamber 11, then the first return smoke pipe 15, through the front smoke box 14, then the second return smoke pipe 17, and out through the rear smoke box 16. It then enters the external economizer through the connecting flue 18 and exits from the bottom outlet of the economizer. The function of the fire baffle 46 is to increase the flue gas resistance, increase the fluidization circulation ratio, prolong the residence time of high-temperature flue gas, increase the heat storage and temperature of the furnace in the fluidized zone, and improve the combustion efficiency. Secondly, the dispersion tube 22 adopts a quick-release design, which allows for quick installation and disassembly of the dispersion tube 22 and the feed tube 6 through threaded fixing. When the dispersion tube 22 is spirally twisted into the feed tube 6, it will squeeze the lower pressure plate 41, causing the piston rod 40 to insert into the piston chamber 39. This allows the gas inside the piston chamber 39 to be discharged into the limiting chamber 44 through the connecting pipe 43, causing the limiting rod 45 to push the slider 29 to move. This causes the gear 31 on the rotating shaft 30 to mesh with the gear ring 27, and the gear 32 to mesh with the gear ring 36, completing the installation of the crushing parts. When the high-pressure blower of the blower 5 blows the biomass pellets into the dispersion tube 22 through the feed tube 6, since the flow from the feed tube 6 into the dispersion tube 22 is a large pipe to a small pipe, the flow rate will increase when the fluid (liquid or gas) flows from the large pipe diameter to the small pipe diameter. This is due to the continuous flow... The flow rate is determined by both the conservation equation (mass conservation) and Bernoulli's equation (energy conservation). Therefore, when entering the dispersion tube 22, the flow rate will increase and flush the spiral blades 26 inside the rotating ring 25, causing the rotating ring 25 to rotate with the toothed ring 27. The toothed ring 27 meshes with the gear 31 on the rotating shaft 30, so the rotating shaft 30 will rotate with the gear 32. The gear 32 meshes with the toothed ring 36 on the rotating ring 34, thus driving the rotating ring 34 to rotate rapidly and carrying the internal dispersing rod 35 to rotate rapidly. The dispersing rod 35 is located in the feed pipe 6, inside the large pipe, where the flow rate is lower than that in the small pipe. The rotation speed of the dispersing rod 35 is higher than the flow rate inside the feed pipe 6, thus dispersing the incoming biomass pellets and preventing them from clumping together, which would affect the combustion efficiency.
[0035] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concept, should be covered within the scope of protection of the present invention.
Claims
1. A WNF-type built-in fluidized bed biomass steam boiler, comprising a base (1), wherein a shell (2) is fixedly installed on the upper surface of the base (1), characterized in that: A straight furnace liner (8) is fixedly installed inside the outer shell (2). A fluidized bed mechanism is provided inside the straight furnace liner (8). The fluidized bed mechanism includes an air distribution plate (20) fixedly installed inside the straight furnace liner (8). A fire baffle (46) is fixedly installed on the right end face of the air distribution plate (20). Multiple sets of air caps (21) are provided on the air distribution plate (20). A feed pipe (6) is fixedly installed on the left end face of the outer shell (2). One end of the feed pipe (6) extends into the interior of the straight furnace liner (8) and is fixedly connected to the air distribution plate (20). A dispersion pipe (22) is provided on the upper side of the air distribution plate (20). The dispersion pipe (22) penetrates the air distribution plate (20) and is spirally fixedly connected to the feed pipe (6). A spiral air duct (23) is fixedly installed at the end of the dispersion pipe (22).
2. The WNF type furnace-embedded fluidized bed biomass steam boiler according to claim 1, characterized in that: A hopper (3) is provided on the left side of the outer shell (2). A screw feeder (4) is connected to the lower end face of the hopper (3). A blower (5) and a blower (7) are provided on the lower side of the screw feeder (4). The screw feeder (4) and the blower (5) are both connected to the feed pipe (6). The blower (7) and the feed pipe (6) are both connected to the straight furnace liner (8) and are located on the lower side of the air distribution plate (20).
3. A WNF-type built-in fluidized bed biomass steam boiler according to claim 2, characterized in that: The outer surface of the outer shell (2) is connected to a valve. An ignition port (10) is opened on the left end of the outer shell (2) corresponding to the straight furnace liner (8). The right end of the straight furnace liner (8) is connected to a corrugated furnace liner (9). The right end of the corrugated furnace liner (9) is connected to a combustion chamber (11). The lower end of the combustion chamber (11) is connected to an ash pipe (12). The ash pipe (12) extends to the outside of the outer shell (2).
4. A WNF-type built-in fluidized bed biomass steam boiler according to claim 3, characterized in that: The right end face of the outer shell (2) is provided with an inspection hole (13). The front smoke box (14) is fixedly installed on the left side inside the outer shell (2). Multiple sets of first return smoke pipes (15) are provided between the front smoke box (14) and the combustion chamber (11). The rear smoke box (16) is fixedly installed on the right end face of the outer shell (2).
5. A WNF-type built-in fluidized bed biomass steam boiler according to claim 4, characterized in that: Multiple sets of second return smoke pipes (17) are connected between the rear smoke box (16) and the front smoke box (14). A connecting flue (18) is connected to the outer surface of the rear smoke box (16). The connecting flue (18) is connected to an external energy-saving device. Multiple sets of main steam valves (19) are connected to the upper side of the outer surface of the outer shell (2).
6. A WNF-type built-in fluidized bed biomass steam boiler according to claim 5, characterized in that: The fluidized bed mechanism also includes a crushing component disposed inside the dispersion tube (22). The crushing component also includes a groove (24) opened on the inner wall of the dispersion tube (22). A rotating ring (25) is rotatably connected inside the groove (24). Multiple sets of spiral blades (26) are fixedly installed on the inner wall of the rotating ring (25).
7. A WNF-type built-in fluidized bed biomass steam boiler according to claim 6, characterized in that: A gear ring (27) is fixedly installed on the upper end face of the rotating ring (25). An inner cavity (28) is opened inside the air distribution plate (20). A rotating shaft (30) is provided inside the inner cavity (28). A gear (31) is fixedly installed on the upper end of the rotating shaft (30). A slot (37) is opened between the inner cavity (28) and the groove (24). The gear meshes with the gear ring (27) through the slot (37).
8. A WNF-type built-in fluidized bed biomass steam boiler according to claim 7, characterized in that: The inner wall of the feed pipe (6) is provided with a groove 2 (33), and a rotating ring 2 (34) is rotatably connected inside the groove 2 (33). A toothed ring 2 (36) is fixedly installed on the outer surface of the rotating ring 2 (34). Multiple sets of dispersing rods (35) are fixedly installed on the inner wall of the rotating ring 2 (34). The outer surface of the feed pipe (6) is provided with a slot 2 (38), and the slot 2 (38) is connected to the groove 2 (33). A gear 2 (32) is provided inside the slot 2 (38), and the gear 2 (32) meshes with the toothed ring 2 (36). The lower end of the rotating shaft (30) extends to the outside of the inner cavity (28) and is fixedly connected to the gear 2 (32).
9. A WNF-type built-in fluidized bed biomass steam boiler according to claim 8, characterized in that: The feed pipe (6) has a piston chamber (39) inside. A piston rod (40) is slidably connected inside the piston chamber (39). A lower pressure plate (41) is fixedly installed at the upper end of the piston rod (40). The lower pressure plate (41) is located on the lower side of the dispersion pipe (22). A spring (42) is fixedly installed between the lower pressure plate (41) and the inner wall of the piston chamber (39).
10. A WNF-type built-in fluidized bed biomass steam boiler according to claim 9, characterized in that: The outer surface of the rotating shaft (30) is fitted with a slider (29), which is rotatably connected to the rotating shaft (30). The slider (29) is slidably connected to the inner cavity (28). A limiting cavity (44) is opened on the inner wall of the inner cavity (28). A limiting rod (45) is slidably connected inside the limiting cavity (44). The limiting rod (45) is fixedly connected to the slider (29). A connecting pipe (43) is provided between the limiting cavity (44) and the piston cavity (39).