Biomass combustion furnace

Abstract

The application relates to a biomass combustion furnace and relates to the field of combustion furnace equipment, comprising a furnace chamber, one side of the furnace chamber is provided with a feeding end, the other side of the furnace chamber is a discharging end, a grate plate is arranged at the inside of the furnace chamber close to the feeding end, an air inlet assembly is arranged below the grate plate, a feeding assembly for feeding biomass fuel is arranged above the grate plate, ventilation openings are formed in the grate plate, a dryer is arranged on one side of the furnace chamber close to the discharging end, and the feeding port of the dryer is communicated with the inside of the furnace chamber. The application has the effects of reducing the coking caused by the accumulation of biomass fuel in the furnace, improving the uniformity of biomass distribution, and fully burning the biomass.

Description

Technical Field

[0001] This application relates to the field of combustion furnace equipment, and in particular to a biomass combustion furnace. Background Technology

[0002] Biomass combustion furnaces are core equipment for achieving efficient and stable thermochemical conversion of biomass fuels (such as wood chips, straw, rice husks, etc.) to obtain thermal energy. Currently, in industrial and heating applications, based on significant differences in combustion organization methods and structural designs, biomass combustion furnaces commonly fall into two categories: 1. Fluidized bed biomass combustion furnaces; 2. Grate conveyor biomass combustion furnaces.

[0003] The core technology of a fluidized bed biomass combustion furnace lies in fluidized bed combustion. Its core structure typically includes a vertically or nearly vertically arranged cylindrical combustion chamber (the shell). An air distribution device is located at the bottom of the combustion chamber. High-pressure primary air (usually preheated air) is blown upwards into the furnace from the air distribution device, causing the biomass fuel particles (usually requiring small size and uniform distribution) inside to be lifted by the airflow, entering a state of vigorous motion similar to liquid boiling, forming the so-called "fluidized bed" or "fluidized layer." In this state, the fuel particles and air achieve turbulent mixing, creating a gas-solid contact surface area.

[0004] A grate-feed biomass combustion furnace utilizes a mechanical grate system as the basic platform for fuel delivery and combustion. The grate typically consists of movable metal grate plates laid at the bottom of the furnace. Fuel is continuously or intermittently fed to the front of the grate via a feeding device. As the grate moves slowly, the fuel layer is gradually conveyed in a specific direction. During this conveying process, the fuel undergoes a typical stoker combustion process: in the front region of the grate, the fuel mainly receives radiant heat from the furnace and convective heat from the high-temperature flue gas, completing preheating and drying; in the middle region of the grate, the fuel reaches ignition temperature and enters a vigorous combustion stage, releasing most of the volatiles and burning fixed carbon; this region usually requires primary air; in the rear region of the grate, combustion enters the burnout stage, where unburned residual carbon is further burned, and the resulting ash is conveyed to the end of the grate for discharge.

[0005] Regarding the aforementioned technologies, the inventors believe that biomass fuel often accumulates inside the furnace, leading to incomplete combustion and coking during the combustion process. Utility Model Content

[0006] In order to reduce the coking caused by biomass fuel accumulation in the furnace and improve the uniformity of biomass distribution to ensure complete combustion, this application provides a biomass combustion furnace.

[0007] This application provides a biomass combustion furnace, which adopts the following technical solution:

[0008] A biomass combustion furnace includes a furnace chamber, with a feed end on one side and a discharge end on the other side. A grate plate is located inside the furnace chamber near the feed end, an air inlet assembly is located below the grate plate, and a feed assembly for feeding biomass fuel is located above the grate plate. Ventilation openings are provided on the grate plate. A dryer is located on the side of the furnace chamber near the discharge end, and the feed inlet of the dryer communicates with the interior of the furnace chamber.

[0009] Optionally, a partition wall is fixedly connected to the furnace chamber, and the partition wall is fixedly connected to the grate plate. The partition wall and the grate plate divide the interior of the furnace chamber into a boiling section located above the grate plate and an air inlet section located below the grate plate. The boiling section and the air inlet section are connected through the ventilation opening.

[0010] Optionally, the grate plate includes a support component and a grate component, the support component is located above the grate component, the vent is opened on the grate component, and the diameter of the grate component gradually decreases along the height direction from low to high.

[0011] Optionally, the grate component includes a bottom support portion and a top protrusion portion. A first locking plate is fixedly connected to the inner sidewall of the bottom support portion. The height of the top wall of the first locking plate is lower than the height of the top wall of the bottom support portion. The first locking plate and the bottom support portion form a first step, and the bottom wall of the top protrusion portion is locked in the first step.

[0012] Optionally, the bottom support portion includes multiple bottom support plates, which are snapped together circumferentially to form the bottom support portion. Each bottom support plate includes a first plate body, a second engaging plate is fixedly connected to one side of the first plate body, and a second engaging groove is provided on the other side of the first plate body. When two adjacent bottom support plates abut together circumferentially, the second engaging plate is located in the second engaging groove.

[0013] Optionally, the top protrusion includes a plurality of top protrusion plates, which are snapped together circumferentially to form the top protrusion. Each top protrusion plate includes a second plate body, a third engaging plate is fixedly connected to one side of the second plate body, and a third engaging groove is provided on the other side of the second plate body. When two adjacent top protrusion plates abut against each other, the third engaging plate is located in the third engaging groove.

[0014] Optionally, a windbreak wall is vertically installed inside the furnace chamber, located between the grate plate and the dryer, and an air vent is provided on the lower side wall of the windbreak wall.

[0015] Optionally, the feeding assembly includes a screw feeder, the outlet of which is provided with a feed chute, one end of which is opposite to the outlet end of the screw feeder, and the other end of which is opposite to the center point of the grate plate.

[0016] Optionally, the dryer is a multi-pass dryer, which includes an inner cylinder, an outer cylinder coaxially disposed on the outside of the inner cylinder, and a middle cylinder disposed between the inner cylinder and the outer cylinder. The inner cylinder and the middle cylinder are connected through a first connecting port, and the middle cylinder and the outer cylinder are connected through a second connecting port. The first connecting port is located on the side of the multi-pass dryer away from the furnace chamber, and the second connecting port is located on the side of the multi-pass dryer closer to the furnace chamber.

[0017] Optionally, lifting plates are provided on the inner wall of the inner cylinder, the inner wall of the middle cylinder, and the inner wall of the outer cylinder.

[0018] In summary, this application includes at least one of the following beneficial technical effects:

[0019] 1. Utilizing the principle of fluidized bed furnace, the blower blows the biomass fuel into combustion, making it less prone to coking; feeding is done using a screw feeder outside the furnace, increasing service life; the conical grate plate ensures more uniform distribution of biomass and more complete combustion;

[0020] 2. Adding a windbreak wall inside the furnace chamber can prevent ash from settling, reduce the ash content in the dried finished sand, and improve product quality. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of a biomass combustion furnace according to an embodiment of this application.

[0022] Figure 2 This is a schematic diagram of the internal structure of a biomass combustion furnace according to an embodiment of this application.

[0023] Figure 3 This is a top view of the grate plate of a biomass combustion furnace according to an embodiment of this application.

[0024] Figure 4 This is a schematic diagram of the structure of a dryer in a biomass combustion furnace according to an embodiment of this application.

[0025] Explanation of reference numerals in the attached drawings: 1. Furnace chamber; 11. Partition wall; 12. Air inlet; 13. Fluidized bed; 14. Baffle wall; 141. Air outlet; 2. Feeding assembly; 21. Screw feeder; 22. Feed chute; 3. Grate plate; 31. Ventilation opening; 32. Grate component; 321. Bottom support; 322. Top protrusion; 4. Air inlet assembly; 41. Make-up air fan; 5. Dryer; 51. Inner cylinder; 52. Middle cylinder; 53. Outer cylinder; 54. First connecting port; 55. Second connecting port; 56. Lifting plate; 6. River sand feeder. Detailed Implementation

[0026] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0028] Biomass combustion furnaces are core equipment for achieving efficient and stable thermochemical conversion of biomass fuels (such as wood chips, straw, rice husks, etc.) to obtain thermal energy. Currently, in industrial and heating applications, based on significant differences in combustion organization methods and structural designs, biomass combustion furnaces commonly fall into two categories: 1. Fluidized bed biomass combustion furnaces; 2. Grate conveyor biomass combustion furnaces.

[0029] The core technology of a fluidized bed biomass combustion furnace lies in fluidized bed combustion. Its core structure typically includes a vertically or nearly vertically arranged cylindrical combustion chamber (the shell). An air distribution device is located at the bottom of the combustion chamber. High-pressure primary air (usually preheated air) is blown upwards into the furnace from the air distribution device, causing the biomass fuel particles (usually requiring small size and uniform distribution) inside to be lifted by the airflow, entering a state of vigorous motion similar to liquid boiling, forming the so-called "fluidized bed" or "fluidized layer." In this state, the fuel particles and air achieve turbulent mixing, creating a gas-solid contact surface area.

[0030] A grate-feed biomass combustion furnace utilizes a mechanical grate system as the basic platform for fuel delivery and combustion. The grate typically consists of movable metal grate plates laid at the bottom of the furnace. Fuel is continuously or intermittently fed to the front of the grate via a feeding device. As the grate moves slowly, the fuel layer is gradually conveyed in a specific direction. During this conveying process, the fuel undergoes a typical stoker combustion process: in the front region of the grate, the fuel mainly receives radiant heat from the furnace and convective heat from the high-temperature flue gas, completing preheating and drying; in the middle region of the grate, the fuel reaches ignition temperature and enters a vigorous combustion stage, releasing most of the volatiles and burning fixed carbon; this region usually requires primary air; in the rear region of the grate, combustion enters the burnout stage, where unburned residual carbon is further burned, and the resulting ash is conveyed to the end of the grate for discharge.

[0031] Regarding the aforementioned technologies, the inventors believe that biomass fuel often accumulates inside the furnace, leading to incomplete combustion and coking during the combustion process.

[0032] In order to reduce the coking caused by biomass fuel accumulation in the furnace and improve the uniformity of biomass distribution to ensure complete combustion, this application provides a biomass combustion furnace.

[0033] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0034] This application discloses a biomass combustion furnace. (Refer to...) Figure 1 , Figure 2 A biomass combustion furnace includes a furnace chamber 1, with a feed end on one side and a discharge end on the side opposite to the feed end. A feed assembly 2 is installed on the feed end side of the furnace chamber 1 to feed biomass fuel into the furnace chamber 1 for combustion. A grate plate 3 is installed inside the furnace chamber 1, located below the discharge port of the feed assembly 2. An air inlet assembly 4 is installed on the side wall of the furnace chamber 1 relative to the lower part of the grate plate 3, to inject outside air into the area below the grate plate 3. A ventilation opening 31 is provided on the grate plate 3, completely penetrating the side wall of the grate plate 3, thereby allowing gas from below the grate plate 3 to flow above it, blowing up the biomass fuel above the grate plate 3 and reducing the accumulation and coking of the biomass fuel.

[0035] A dryer 5 is also provided at the discharge end of the furnace chamber 1. In a specific embodiment, the dryer 5 is a multi-pass dryer 5. The multi-pass dryer 5 has a small footprint while meeting the requirements of large production capacity, and at the same time, it reduces heat loss and has high thermal efficiency.

[0036] The furnace chamber 1 is insulated with refractory bricks, alumina needled blankets, refractory mud, clay or slag insulation materials to reduce heat loss.

[0037] A partition wall 11 is vertically installed inside the furnace chamber 1 on one side opposite the grate plate 3. The side wall of the partition wall 11 is fixedly connected to the side wall of the furnace chamber 1, and the partition wall 11 completely covers the side wall of the grate plate 3. Thus, the partition wall 11 and the grate plate 3 divide the interior of the furnace chamber 1 into an air inlet section 12 located below the grate plate 3 and a boiling section 13 located above the grate plate 3. The air inlet section 12 is connected to the air inlet assembly 4, and the boiling section 13 is connected to the feed assembly 2. The air inlet section 12 and the boiling section 13 are connected to each other through the air inlet on the grate plate 3. This allows the air introduced by the air inlet assembly 4 to enter the interior of the air inlet section 12, and the gas inside the air inlet section 12 to enter the boiling section 13 through the air inlet. The high-speed air blows the biomass fuel inside the boiling section 13, improving the combustion efficiency of the biomass fuel and reducing coking.

[0038] The air intake assembly 4 includes a makeup air fan 41, which is located outside the furnace chamber 1. The air outlet of the makeup air fan 41 is connected to an air collection box. The air collection box is connected to the makeup air fan 41. An air valve is provided at the air outlet of the air collection box. An air inlet pipe is provided on the side of the air valve away from the air collection box. The air inlet pipe extends into the interior of the furnace chamber 1 and is located below the grate plate 3.

[0039] The feeding assembly 2 includes a screw feeder 21, which is used to replenish biomass fuel to the interior of the furnace chamber 1. A feed chute 22 is also provided at the outlet end of the screw feeder 21. One end of the feed chute 22 is opposite to the outlet of the screw feeder 21, and the feed chute 22 extends into the interior of the furnace chamber 1. The outlet of the feed chute 22 is opposite to the center of the grate plate 3. The biomass fuel output from the screw feeder 21 is replenished into the interior of the furnace chamber 1 through the feed chute 22.

[0040] Reference Figure 2 , Figure 3 The grate plate 3 includes a support member at the bottom and a grate component 32 above the support member. The support member includes multiple support beams, the ends of which extend from the side wall of the grate component 32. A limiting plate is fixedly connected to the outside of the support beams of the grate component 32. The limiting plate is vertically arranged, and its side wall abuts against the outer side wall of the grate component 32. The limiting plate reduces the movement of the grate component 32 on the support beams and limits the movement of the grate component 32.

[0041] The grate component 32 includes a bottom support portion 321 at the bottom and a top protrusion 322 at the top. The bottom support portion 321 abuts against a support beam, and the top protrusion 322 abuts against the bottom support portion 321. The bottom support portion 321 has a ring-shaped structure, and the top protrusion 322 is located above the inner ring of the bottom support portion 321. The top protrusion 322 has a conical structure, with the top protrusion protruding upward from the bottom support portion 321. The diameter of the grate component 32 gradually decreases along its height direction from low to high.

[0042] The inner ring of the bottom support portion 321 is fixedly connected to a first engaging plate. The top wall of the first engaging plate is lower than the top wall of the bottom support portion 321, so that the bottom wall of the first engaging plate and the top wall of the bottom support portion 321 form a first step. The bottom end of the top protrusion 322 is engaged inside the first step, thereby engaging and connecting the bottom support portion 321 and the top protrusion 322 relative to each other.

[0043] The bottom support portion 321 includes a plurality of bottom support plates arranged circumferentially to abut against each other, forming a ring structure along the circumferential direction to form the bottom support portion 321. Each bottom support plate includes a first plate body, a second engaging plate fixedly connected to one side wall of the first plate body along the circumferential direction, and a second engaging groove formed on the other side wall of the first plate body along the circumferential direction. The second engaging plate and the second engaging groove are opposite to each other. When two adjacent bottom support plates abut against each other circumferentially, the second engaging plate of one bottom support plate can extend into the second engaging groove of the other bottom support plate, thereby engaging and connecting the two bottom support plates.

[0044] The top protrusion 322 includes a plurality of top protruding plates arranged circumferentially to abut against each other, forming a ring structure along the circumferential direction to form the top protrusion 322. Each top protrusion includes a second plate body, a third engaging plate fixedly connected to one side wall of the second plate body along the circumferential direction, and a third engaging groove formed on the other side wall of the second plate body along the circumferential direction, with the third engaging plate and the third engaging groove facing each other. When two adjacent top protrusions abut against each other circumferentially, the third engaging plate of one top protrusion can extend into the third engaging groove of the other top protrusion, thereby engaging and connecting the two top protrusions.

[0045] The top of the top protrusion 322 is provided with a second engaging groove, and a second step is formed between the second engaging groove and the top protrusion 322. A top plate is provided inside the second step, and the top plate is engaged inside the second step. The top plate has a circular structure and is coaxially arranged with the top protrusion 322.

[0046] A windbreak wall 14 is vertically installed inside the furnace chamber 1. The windbreak wall 14 is located between the grate plate 3 and the dryer 5. The windbreak wall 14 completely covers the vertical section of the furnace chamber 1, and the lower side wall of the windbreak wall 14 has a horizontal air outlet 141. The air outlet connects the space inside the furnace chamber 1 near the grate plate 3 with the space inside the furnace chamber 1 near the dryer 5. This can prevent ash from settling, reduce the ash content in the dried finished sand, and improve product quality.

[0047] Reference Figure 1 , Figure 4 A river sand feeder 6 is installed between the multi-pass dryer 5 and the furnace chamber 1. The feed end of the river sand feeder 6 is connected to the interior of the furnace chamber 1, and the discharge end of the river sand feeder 6 is connected to the feed end of the multi-pass dryer 5. An emergency sand discharge port is also provided on one side of the river sand feeder 6.

[0048] The multi-pass dryer 5 includes an inner cylinder 51, which is horizontally arranged and connected to the outlet end of the river sand feeder 6. A middle cylinder 52 is coaxially sleeved on the outside of the inner cylinder 51. A gap is left between the inner wall of the middle cylinder 52 and the outer wall of the inner cylinder 51. A gap is also left between the end of the inner cylinder 51 facing away from the furnace chamber 1 and the end of the middle cylinder 52 facing away from the furnace chamber 1 to form a first connecting port 54. The first connecting port 54 connects the interiors of the inner cylinder 51 and the middle cylinder 52, allowing the material inside the inner cylinder 51 to enter the interior of the middle cylinder 52 through the first connecting port 54.

[0049] An outer cylinder 53 is coaxially sleeved on the outside of the middle cylinder 52. There is a gap between the inner wall of the outer cylinder 53 and the outer wall of the middle cylinder 52. A second communication port 55 is formed between the end of the middle cylinder 52 near the furnace chamber 1 and the end of the outer cylinder 53 near the furnace chamber 1. The second communication port 55 connects the inside of the middle cylinder 52 with the inside of the outer cylinder 53, so that the material inside the middle cylinder 52 can enter the inside of the outer cylinder 53 through the second communication port 55.

[0050] By placing the middle cylinder 52 outside the inner cylinder 51 and the outer cylinder 53 outside the middle cylinder 52, the floor space is reduced. Furthermore, due to the multi-layer arrangement, heat can be transferred between adjacent layers, reducing heat loss and improving thermal efficiency.

[0051] Lifting plates 56 are fixedly connected to the inner wall of the inner cylinder 51, the inner wall of the middle cylinder 52, and the inner wall of the outer cylinder 53. Multiple lifting plates 56 are provided on the inner wall of the inner cylinder 51, the inner wall of the middle cylinder 52, and the inner wall of the outer cylinder 53. While pushing the material forward, the lifting plates 56 disperse the material and increase the heat exchange area of ​​the cylinder with hot air.

[0052] In this application, the term "multiple" refers to at least two or more, unless otherwise expressly defined. The terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "linking" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0053] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A biomass combustion furnace, characterized in that: It includes a furnace chamber (1), with a feeding end on one side of the furnace chamber (1) and a discharging end on the other side. A grate plate (3) is provided inside the furnace chamber (1) near the feeding end. An air inlet assembly (4) is provided below the grate plate (3). A feeding assembly (2) for feeding biomass fuel is provided above the grate plate (3). A ventilation opening (31) is provided on the grate plate (3). A dryer (5) is provided on the side of the furnace chamber (1) near the discharging end. The feed inlet of the dryer (5) is connected to the interior of the furnace chamber (1).

2. The biomass combustion furnace according to claim 1, characterized in that: A partition wall (11) is fixedly connected inside the furnace chamber (1). The partition wall (11) is fixedly connected to the grate plate (3). The partition wall (11) and the grate plate (3) divide the interior of the furnace chamber (1) into a boiling section (13) located above the grate plate (3) and an air inlet section (12) located below the grate plate (3). The boiling section (13) and the air inlet section (12) are connected through the vent (31).

3. The biomass combustion furnace according to claim 1, characterized in that: The grate plate (3) includes a support component and a grate component (32). The support component is located above the grate component (32). The vent (31) is opened on the grate component (32). The diameter of the grate component (32) gradually decreases along the height direction from low to high.

4. The biomass combustion furnace according to claim 3, characterized in that: The grate component (32) includes a bottom support portion (321) and a top protrusion portion (322). The inner sidewall of the bottom support portion (321) is fixedly connected to a first locking plate. The height of the top wall of the first locking plate is lower than the height of the top wall of the bottom support portion (321). The first locking plate and the bottom support portion (321) form a first step. The bottom wall of the top protrusion portion (322) is locked in the first step.

5. The biomass combustion furnace according to claim 4, characterized in that: The bottom support portion (321) includes a plurality of bottom support plates, which are snapped together along the circumferential direction to form the bottom support portion (321). Each bottom support plate includes a first plate body, a second locking plate is fixedly connected to one side of the first plate body, and a second locking groove is provided on the other side of the first plate body. When two adjacent bottom support plates abut together along the circumferential direction, the second locking plate is located in the second locking groove.

6. The biomass combustion furnace according to claim 4, characterized in that: The top protrusion (322) includes a plurality of top protrusion plates, which are snapped together in a circumferential manner to form the top protrusion (322). Each top protrusion plate includes a second plate body, a third engaging plate is fixedly connected to one side of the second plate body, and a third engaging groove is provided on the other side of the second plate body. When two adjacent top protrusion plates abut against each other, the third engaging plate is located in the third engaging groove.

7. The biomass combustion furnace according to claim 1, characterized in that: A windbreak wall (14) is vertically installed inside the furnace chamber (1). The windbreak wall (14) is located between the grate plate (3) and the dryer (5). An air vent (141) is opened on the lower side wall of the windbreak wall (14).

8. The biomass combustion furnace according to claim 1, characterized in that: The feeding assembly (2) includes a screw feeder (21), and a feed chute (22) is provided at the outlet of the screw feeder (21). One end of the feed chute (22) is opposite to the outlet end of the screw feeder (21), and the other end of the feed chute (22) is opposite to the center point of the grate plate (3).

9. The biomass combustion furnace according to claim 1, characterized in that: The dryer (5) is a multi-pass dryer (5). The multi-pass dryer (5) includes an inner cylinder (51). An outer cylinder (53) is coaxially arranged on the outside of the inner cylinder (51). A middle cylinder (52) is also arranged between the inner cylinder (51) and the outer cylinder (53). The inner cylinder (51) and the middle cylinder (52) are connected through a first connecting port (54). The middle cylinder (52) and the outer cylinder (53) are connected through a second connecting port (55). The first connecting port (54) is located on the side of the multi-pass dryer (5) away from the furnace chamber (1). The second connecting port (55) is located on the side of the multi-pass dryer (5) close to the furnace chamber (1).

10. The biomass combustion furnace according to claim 9, characterized in that: The inner wall of the inner cylinder (51), the inner wall of the middle cylinder (52), and the inner wall of the outer cylinder (53) are all provided with lifting plates (56).

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