Ash discharging device and method of fixed-bed biomass gasifier

Abstract

The application relates to an ash and slag discharging device and method of a fixed-bed biomass gasification furnace, which comprises a furnace body, a rotating ash basin arranged at the bottom of the furnace body and not in contact with the furnace body, a rotating furnace discharge tower arranged in the rotating ash basin and synchronously rotating with the rotating ash basin, the top of the rotating furnace discharge tower extending into the furnace body and the bottom being connected with a ventilation system, a slag channel located between the inner wall of the rotating ash basin and the rotating furnace discharge tower and used for collecting ash and slag, the side wall of the slag channel being provided with an ash outlet for discharging the ash and slag, and an ash discharging assembly comprising a plurality of ash scraping knives installed on the outer side wall of the rotating furnace discharge tower, a plurality of small ash knives installed on the bottom of the furnace body and a large ash knife installed on the outer side wall of the furnace body. Compared with the prior art, the ash and slag discharging device and method can effectively avoid the problem of ash and slag blockage, improve the slag discharging efficiency, directly discharge the ash and slag to a specified position outside and provide strong support for efficient utilization of biomass energy.

Description

Technical Field

[0001] This invention relates to the field of ash removal technology for biomass gasifiers, and in particular to an ash removal device and method for a fixed-bed biomass gasifier. Background Technology

[0002] Biomass gasification is a thermochemical process in which biomass feedstock undergoes pyrolysis, oxidation, reduction, and reforming reactions under specific thermal conditions using a gasifying agent (air, oxygen, or steam, etc.) to promote the formation of smaller hydrocarbon molecules from carbon and hydrogen polymers within the biomass. After a series of chemical reactions, the biomass material becomes combustible gas, which is directly discharged into the boiler for combustion. The ash residue from the combustion and pyrolysis is discharged from the furnace. Currently, gasifier ash removal can be done manually or mechanically. Manual ash removal uses shovels or similar tools to scoop the ash from the ash hopper and collect it for processing. This method is simple to operate but labor-intensive. Mechanical ash removal often uses a screw conveyor to remove the ash from the bottom, but if the ash is lumpy, it can easily cause the ash removal machine to jam or be damaged.

[0003] Patent publication number CN105737164A discloses a waste pyrolysis gasification furnace, in which the furnace base is set in an ash pan. A scraper is welded onto the ash pan, which is rotated by a motor, carrying the ash and slag into the pan out through the scraper. Two rows of small air holes are provided on both sides of the scraper. However, this pyrolysis gasification furnace's rotating ash pan only discharges ash and slag into an ash basin, resulting in slow ash removal efficiency and the inability to discharge it to a designated external location, requiring manual ash removal. Furthermore, if the ash and slag harden due to high-temperature melting, the scraper may not be able to effectively carry it out, leading to poor ash removal or even equipment jamming. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects of the prior art by providing an ash and slag removal device and method for a fixed-bed biomass gasifier, which can effectively avoid the problem of ash and slag blockage, improve slag removal efficiency, and directly discharge ash and slag to a designated external location, thus providing strong support for the efficient utilization of biomass energy.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] In one aspect, the present invention provides an ash and slag removal device for a fixed-bed biomass gasification furnace, comprising:

[0007] A rotating ash basin located at the bottom of the gasifier body but not in contact with it;

[0008] A rotating grate tower is installed inside the rotating ash basin and rotates synchronously therewith, with the top of the rotating grate tower extending into the furnace body and the bottom connected to a ventilation system;

[0009] A slag chute located between the inner wall of the rotating ash basin and the rotating grate tower for collecting ash and slag has an ash outlet on its side wall for discharging ash and slag.

[0010] And an ash removal assembly, which includes a plurality of ash scrapers installed on the outer wall of the rotary grate tower, a plurality of small ash scrapers installed on the bottom of the furnace body, and a large ash scraper installed on the outer wall of the furnace body.

[0011] Furthermore, the furnace body is cylindrical, with its top connected and supported by an external structure, and its bottom having a certain distance from the rotating ash basin, creating a suspended effect for the furnace body.

[0012] Furthermore, the scraper blade includes a conical structure and a cylindrical structure, with its circular bottom connected to the outer wall of the rotating grate tower;

[0013] Two scraper blades are provided, symmetrically distributed on both sides of the rotary grate tower.

[0014] Furthermore, the small ash shavings have a sheet-like structure with a gradually decreasing thickness. The end of the small ash shavings furthest from the rotating grate tower has the greatest thickness, while the end closest to the rotating grate tower has the smallest thickness. In other words, the tip of the small ash shavings faces inward.

[0015] Furthermore, the cross-sectional shape of the small ash cutter is the same at any height. The cross-section is a curved-side triangle, a closed figure formed by a first arc, a first straight line, and a second straight line. The thickness of the small ash cutter represents the length of any arc parallel to the first arc between the first and second straight lines.

[0016] Furthermore, the first arc is consistent with the curvature of the side wall of the furnace body and is located directly below the side wall of the furnace body.

[0017] Furthermore, the tangential angle between the first arc and the first straight line is 20°~30°, the tangential angle between the first arc and the second straight line is 130°~140°, and the vertex angle between the first and second straight lines is 15°~20°. The tangential angle between the first arc and the first straight line is the angle formed by the tangent direction of the first arc and the first straight line at the connection point. The vertex angle between the first arc and the second straight line is the angle formed by the tangent direction of the first arc and the second straight line at the connection point. The direction of the vertex angle between the first and second straight lines is consistent with the rotation direction of the rotating ash basin.

[0018] Furthermore, the ratio of the first arc of the small gray knife to the height of the small gray knife is 1 to 5, preferably 1 to 2.

[0019] Furthermore, there are 4 to 8 small ash knives, which are distributed at equal intervals in a circle along the bottom edge of the furnace body, and the shape, size and direction of the small ash knives are consistent.

[0020] Furthermore, the large ash shovel is a sheet-like structure that is inclined from top to bottom on the outer wall of the furnace body, and its width gradually decreases from top to bottom.

[0021] Furthermore, the length ratio of the widest to the narrowest point of the large ash shovel is 2-6, preferably 3-4; the ratio of the widest point to the vertical height is 0.2-2, preferably 0.5-1.5. The width of the large ash shovel is expressed as the distance along the radial direction from the outer wall of the furnace body to the boundary line of the large ash shovel.

[0022] Furthermore, the tilt angle of the large ash shovel is 25°~40°, and the tilt angle represents the angle between the connecting line of the large ash shovel and the furnace body and the vertical line.

[0023] Furthermore, the side of the large ash shovel that connects to the outer wall of the furnace body is arc-shaped, and the side that is away from the outer wall of the furnace body is arc-shaped, with the two arcs having different curvatures.

[0024] Furthermore, the large ash cutter has a planar structure or a curved structure.

[0025] Furthermore, the large ash shovel is provided with an ash discharge baffle that is attached to it and has one end that extends beyond the width of the large ash shovel.

[0026] Furthermore, looking vertically upwards, with the lowest point of the large ash shovel as the starting point, the ash discharge baffle is located at 50% to 80% of the height of the large ash shovel.

[0027] Furthermore, the width of the ash discharge baffle is 1.1 to 1.5 times the maximum width of the large ash scalpel.

[0028] Furthermore, the horizontal center lines of the putty scraper, small putty scraper, and large putty scraper are not located at the same height.

[0029] Furthermore, the height of its horizontal center line is: putty trowel > large putty trowel > small putty trowel.

[0030] Furthermore, the furnace body and the rotating grate tower are coaxial cylindrical structures, and the center points of the ash scraper, small ash scraper, and large ash scraper along the circumference of the furnace body are not located on the same radial line, and the positions of the ash scraper, small ash scraper, and large ash scraper are staggered.

[0031] Furthermore, the ash and slag discharge device of the gasifier further includes an ash and slag separation and collection assembly for separating and collecting the ash and slag discharged from the ash outlet, which includes:

[0032] Ash discharge chute with screen;

[0033] A small-volume ash collector for collecting small-volume ash residue that falls from the screen;

[0034] And a large volume ash collector for collecting large volumes of ash discharged from the ash discharge trough.

[0035] Furthermore, the ash discharge trough includes a bottom surface with a screen and side baffles disposed on both sides of the bottom surface.

[0036] Furthermore, the bottom surface has a structure that is wider at the top and narrower at the bottom.

[0037] Furthermore, the ash discharge trough is not connected to the rotating ash basin, but is connected and supported by an external steel frame. The external steel frame is a support structure, which is a conventional structure in the field, and is used to support the ash discharge trough.

[0038] Furthermore, the ash discharge trough is inclined.

[0039] Furthermore, an ash discharge baffle is also provided at the ash discharge port.

[0040] Furthermore, the rotary grate tower includes:

[0041] A base is installed inside the ash basin and connected and fixed thereto;

[0042] A conical grate is mounted on the base;

[0043] And an air inlet channel connected to the conical grate for ventilation.

[0044] Furthermore, the scraper blade is disposed on the side wall of the base.

[0045] Furthermore, the base has a cylindrical structure.

[0046] Furthermore, the conical grate is topped with a conical cap pointing upwards, and the cap has several air outlets, each with a spray mask above it. The spray mask protects the air outlets from being blocked by material and changes the direction of the airflow. The raised structure of the spray mask also increases turbulence within the furnace, resulting in more even material distribution.

[0047] Furthermore, several of the air outlets form several concentric ring arrays with the tip of the top cover as the center, and each array is arranged at radial intervals.

[0048] Furthermore, the bottom of the conical grate is a frustum-shaped air inlet, wider at the top and narrower at the bottom, with an open top; the frustum-shaped air inlet is connected to the air intake channel. Air enters through the air intake channel, passes through the air inlet, and reaches the top cover of the rotating grate tower. The incoming air is ambient temperature cold air, which can cool the equipment. Therefore, with the protection of the cold air, the air intake channel and the conical grate will not cause the rotating grate tower to deform or be damaged due to high temperature.

[0049] Furthermore, the air intake channel and the air intake flare are rotatably connected, with the air intake flare rotating about its center line while the air intake channel remains stationary. The specific rotatable connection can employ conventional techniques in the art and is not the focus of this invention.

[0050] Furthermore, the rotating ash basin includes an ash basin body and a rotating mechanism installed at the bottom of the ash basin body and causing it to rotate.

[0051] Furthermore, the ash basin body is an annular basin that is wider at the top and narrower at the bottom, the base of the rotating grate tower is an annular structure base, and the air inlet channel passes through the hollow part in the center of the ash basin body and the base and connects to the conical grate.

[0052] Furthermore, the ash basin body is fixedly connected to the base of the rotating grate tower and rotates synchronously.

[0053] Furthermore, the ash basin body rotates around its own central axis.

[0054] Furthermore, the rotating mechanism adopts a conventional structure in the art, which only needs to enable the ash basin body to rotate around its own central axis. This is not the focus of the present invention, so it will not be described in detail.

[0055] In another aspect, the present invention also provides a method for removing ash and slag from a fixed-bed biomass gasifier, which is implemented using any of the ash and slag removal devices described above.

[0056] Furthermore, the steps of the ash and slag removal method include:

[0057] S1. The rotating ash basin and the rotating grate tower rotate synchronously, driving several ash scrapers to rotate, and the ash and water from the gasification process fall into the slag chute.

[0058] S2. The rotating ash and water move relative to the small and large ash knives, and the small ash knives guide the rotating ash and water to move in an orderly manner in the same direction.

[0059] S3. The large ash cutter intercepts the ash residue, causing it to accumulate at the ash outlet and be discharged.

[0060] Compared with the prior art, the present invention has the following advantages:

[0061] (1) This invention, through the arrangement of a scraper blade, a small scraper blade, and a large scraper blade, wherein the scraper blade is used for general ash removal, the small scraper blade is used for finer ash removal, and the large scraper blade is used for larger ash removal, forms a reasonable and fully functional slag removal system, which greatly improves slag removal efficiency. In addition, the arrangement of the scraper blade, the small scraper blade, and the large scraper blade also extends the service life of the scraper blade, the small scraper blade, and the large scraper blade, reduces the frequency of downtime maintenance, and is conducive to improving slag removal efficiency.

[0062] (2) By setting the scraper, small scraper, and large scraper to have different shapes, heights, and radial positions, the present invention can form a multi-layered slag removal structure, thereby enhancing the slag removal capacity. The different shapes may affect the cutting and pushing efficiency, the different heights may control the thickness of the slag layer, and the different radial positions may cover different areas, ensuring comprehensive slag removal.

[0063] (3) The small ash knife in this invention has a sheet-like structure with a gradually decreasing thickness. The end of the small ash knife furthest from the rotating grate tower has the greatest thickness, and the end closest to the rotating grate tower has the smallest thickness. The cross-sectional shape of the small ash knife at any height is the same, and the cross-section is an arc-sided triangle. The apex angle of the first straight line and the second straight line is consistent with the rotation direction of the rotating ash basin, forcing the ash slag to flow along the set path and avoiding blockage caused by disordered accumulation. Moreover, the sharp apex of the arc-shaped triangle can penetrate the coking block, and the arc-shaped edge provides shearing force to achieve secondary crushing of large slag pieces. The evenly spaced arrangement of several small ash knives ensures that the slag discharge force is evenly distributed in the circumferential direction, avoiding excessive local slag layer thickness from affecting the thermal balance of the gasifier.

[0064] (4) The large ash knife of the present invention is inclined. When the rotating ash slag rotates to the large ash knife, the largest surface of the large ash knife contacts the ash slag, which can intercept part of the ash slag and make it accumulate at the ash outlet. When the accumulation of ash slag reaches a certain level, it is discharged from the ash outlet, which avoids the ash slag from accumulating messily in the slag chute, reduces the cleaning difficulty, and provides great convenience for the subsequent collection and treatment of ash slag.

[0065] (5) By setting up an ash and slag separation and collection component, the ash and slag discharged from the ash outlet enters the ash outlet trough. According to the particle size of the ash and slag, the smaller ash and slag are accurately screened by a screen. The screened ash and slag fall into the small volume ash and slag collector below. The large volume ash and slag that is not filtered by the screen is discharged from the bottom of the ash outlet trough and reaches the large volume ash and slag collector. This is conducive to the centralized collection of large and small volume ash and slag, laying the foundation for subsequent resource recycling and treatment. Attached Figure Description

[0066] Figure 1 This is a schematic diagram of the gasifier shown in Example 1;

[0067] Figure 2This is a top view of the gasifier shown in Example 1;

[0068] Figure 3 This is a schematic diagram of the small ash knife shown in Example 1;

[0069] Figure 4 This is a schematic diagram of the structure of the large ash cutter shown in Example 1;

[0070] Figure 5 This is a side view (ash outlet direction) of the gasifier shown in Example 1.

[0071] Figure 6 This is a top view of the gasifier shown in Example 2;

[0072] Figure 7 This is a schematic diagram of the structure of the large ash cutter with ash baffle shown in Example 2.

[0073] Figure 8 This is a schematic diagram of the conical grate structure shown in Example 3;

[0074] Figure 9 This is a top view of the conical grate shown in Example 3;

[0075] Figure 10 This is a schematic diagram of the gasifier shown in Example 4;

[0076] Figure 11 This is a schematic diagram of the ash discharge trough shown in Example 4.

[0077] Explanation of markings in the diagram:

[0078] 1-Furnace body;

[0079] 2-Rotating ash basin, 21-Ash basin body, 22-Rotating mechanism;

[0080] 3-Rotating grate tower, 31-Base, 32-Conical grate, 321-Top cover, 322-Spray mask, 323-Air inlet flare, 33-Air inlet channel;

[0081] 4-Slag chute, 41-Ash outlet;

[0082] 5-Ash discharge assembly, 51-Ash scraper, 52-Small ash scraper, 521-First arc, 522-First straight line, 523-Second straight line, 53-Large ash scraper, 531-Ash discharge baffle;

[0083] 6-Ash and slag separation and collection component, 61-Ash discharge trough, 611-Bottom surface, 6111-Screen, 612-Side baffle, 62-Small volume ash and slag collector, 63-Large volume ash and slag collector. Detailed Implementation

[0084] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments. In the following embodiments or examples, unless otherwise specified, the functional components or structures are conventional components or structures used in the art to achieve the corresponding functions.

[0085] It should be noted that in the description of this invention, the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0086] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0087] A slag removal device for a fixed-bed biomass gasifier includes:

[0088] A rotating ash basin 2 is located at the bottom of the gasifier body 1 but does not contact it;

[0089] A rotating grate tower 3 is installed inside the rotating ash basin 2 and rotates synchronously therewith. The top of the rotating grate tower 3 extends into the furnace body 1 and the bottom is connected to the ventilation system.

[0090] The slag chute 4, located between the inner wall of the rotating ash basin 2 and the rotating grate tower 3 and used to collect ash and slag, has an ash outlet 41 on its side wall for discharging ash and slag.

[0091] And the ash removal assembly 5, which includes a plurality of ash scrapers 51 installed on the outer wall of the rotary grate tower 3, a plurality of small ash scrapers 52 installed on the bottom of the furnace body 1, and a large ash scraper 53 installed on the outer wall of the furnace body 1.

[0092] In some specific embodiments, the furnace body 1 is cylindrical, with its top connected and supported by an external structure, and its bottom having a certain distance from the rotating ash basin 2, thus creating a suspended effect for the furnace body 1.

[0093] In some specific embodiments, the scraper blade 51 includes a conical structure and a cylindrical structure, with its circular bottom connected to the outer wall of the rotary grate tower 3.

[0094] Two scraper blades 51 are provided, which are symmetrically distributed on both sides of the rotary grate tower 3.

[0095] In some specific embodiments, the small ash shavings 52 have a sheet-like structure with a gradually decreasing thickness. The end of the small ash shavings 52 furthest from the rotating grate tower 3 has the greatest thickness, and the end closest to the rotating grate tower 3 has the smallest thickness. That is, the tip of the small ash shavings 52 faces inward.

[0096] In some specific embodiments, the cross-sectional shape of the small ash cutter 52 at any height is the same, and the cross-section is a curved-side triangle, which is a closed figure formed by a first arc 521, a first straight line 522, and a second straight line 523. The thickness of the small ash cutter 52 represents the length of any arc parallel to the first arc 521 between the first straight line 522 and the second straight line 523.

[0097] In some specific embodiments, the first arc 521 is consistent with the curvature of the side wall of the furnace body 1 and the first arc 521 is located directly below the side wall of the furnace body 1.

[0098] In some specific embodiments, the tangential angle between the arc side of the first arc 521 and the first straight line 522 is 20°~30°, the tangential angle between the arc side of the first arc 521 and the second straight line 523 is 130°~140°, and the vertex angle between the first straight line 522 and the second straight line 523 is 15°~20°. The tangential angle between the arc side of the first arc 521 and the first straight line 522 is the angle formed by the tangent direction of the first arc 521 and the first straight line 522 at the connection point. The tangential angle between the arc side of the first arc 521 and the second straight line 523 is the angle formed by the tangent direction of the first arc 521 and the second straight line 523 at the connection point. The vertex angle between the first straight line 522 and the second straight line 523 is the angle between the first straight line 522 and the second straight line 523 at the connection point. The angular direction of the apex of the first straight line 522 and the second straight line 523 is consistent with the rotation direction of the rotating ash basin 2.

[0099] In some specific embodiments, the ratio of the first arc 521 of the small gray knife 52 to the height of the small gray knife 52 is 1 to 5, preferably 1 to 2.

[0100] In some specific embodiments, there are 4 to 8 small ash knives 52, which are distributed at equal intervals around the bottom edge of the furnace body 1, and the shape, size and direction of the small ash knives 52 are consistent.

[0101] In some specific embodiments, the large ash shovel 53 is a sheet-like structure that is inclined from top to bottom on the outer wall of the furnace body 1, and its width decreases gradually from top to bottom.

[0102] In some specific embodiments, the length ratio of the widest to the narrowest point of the large ash shovel 53 is 2 to 6, preferably 3 to 4; the ratio of the widest point to the vertical height is 0.2 to 2, preferably 0.5 to 1.5. The width of the large ash shovel 53 is expressed as the distance along the radial direction from the outer wall of the furnace body 1 to the boundary line of the large ash shovel 53.

[0103] In some specific embodiments, the tilt angle of the large ash shovel 53 is 25°~40°, and the tilt angle represents the angle between the connecting line of the large ash shovel 53 and the furnace body 1 and the vertical line.

[0104] In some specific embodiments, the side of the large ash shovel 53 that connects to the outer side wall of the furnace body 1 is arc-shaped, and the side that is away from the outer side wall of the furnace body 1 is arc-shaped, with different curvatures of the two arcs.

[0105] Furthermore, the large ash cutter 53 has a planar structure or a curved structure.

[0106] In some specific embodiments, the large ash shovel 53 is provided with an ash discharge baffle 531 that is attached to it and has one end that extends beyond the width of the large ash shovel 53.

[0107] In some specific embodiments, looking from bottom to top along a vertical line, with the lowest point of the large ash shovel 53 as the starting point, the ash discharge baffle 531 is located at 50% to 80% of the height of the large ash shovel 53.

[0108] In some specific embodiments, the width of the ash discharge baffle 531 is 1.1 to 1.5 times the maximum width of the large ash scalpel 53.

[0109] In some specific embodiments, the horizontal center lines of the putty scraper 51, small putty scraper 52, and large putty scraper 53 are not located at the same height.

[0110] In some specific implementations, the height of the horizontal center line is: squeegee 51 > large squeegee 53 > small squeegee 52.

[0111] In some specific embodiments, the furnace body 1 and the rotating grate tower 2 are coaxial cylindrical structures, and the center points of the ash scraper 51, small ash scraper 52 and large ash scraper 53 along the circumference projection of the furnace body 1 are not located on the same radial line, and the positions of the ash scraper, small ash scraper and large ash scraper are staggered.

[0112] In some specific embodiments, the ash and slag discharge device of the gasifier further includes an ash and slag separation and collection assembly 6 for separating and collecting the ash and slag discharged from the ash outlet 41, which includes:

[0113] Ash discharge trough 61 with screen 6111;

[0114] Small volume ash collector 62 for collecting small volume ash slag that falls from the screen 6111;

[0115] And a large volume ash collector 63 for collecting large volumes of ash discharged from the ash discharge trough 61.

[0116] In some specific embodiments, the ash discharge trough 61 includes a bottom surface 611 with a screen 6111 and side baffles 612 disposed on both sides of the bottom surface.

[0117] In some specific embodiments, the bottom surface 611 has a structure that is wider at the top and narrower at the bottom.

[0118] In some specific embodiments, the ash discharge trough 61 is not connected to the rotating ash basin 2, but is connected and supported by an external steel frame. The external steel frame is a support structure, which is a conventional structure in the art, and is used to support the ash discharge trough 61.

[0119] In some specific embodiments, the ash discharge trough 61 is inclined.

[0120] In some specific embodiments, an ash discharge baffle is also provided at the ash discharge port 41.

[0121] In some specific embodiments, the rotary grate tower 3 includes:

[0122] A base 31 is installed inside the ash basin 2 and connected and fixed thereto;

[0123] A conical grate 32 is mounted on the base 31;

[0124] And an air inlet channel 33 connected to the conical grate 32 and used for ventilation.

[0125] In some specific embodiments, the scraper blade 51 is disposed on the side wall of the base 31.

[0126] In some specific embodiments, the base 31 has a cylindrical structure.

[0127] In some specific embodiments, the top of the conical grate 32 is provided with a conical top cover 321 with the tip pointing upwards. The top cover 321 is provided with a plurality of air outlets, and a spray mask 322 is provided above each air outlet. The spray mask 322 protects the air outlet from being blocked by materials and changes the direction of airflow. At the same time, the raised structure of the spray mask 322 can also increase the disturbance inside the furnace, making the material spread more evenly.

[0128] In some specific embodiments, several of the air outlets form several concentric ring arrays with the tip of the top cover 321 as the center, and each array is arranged at intervals along the radial direction.

[0129] In some specific embodiments, the bottom of the conical grate 32 is a frustum-shaped air inlet 323, wider at the top and narrower at the bottom, and the top is not closed; the frustum-shaped air inlet 323 is connected to the air inlet channel 33. Air enters from the air inlet channel 33, passes through the air inlet 323, and reaches the top cover 321 of the rotary grate tower 3. The incoming air is ambient temperature cold air, which can cool the equipment, so the air inlet channel 33 and the conical grate 32 will not cause the rotary grate tower 3 to deform or be damaged due to high temperature under the protection of cold air.

[0130] In some specific embodiments, the air intake channel 33 is rotatably connected to the air intake vent 323, with the air intake vent 323 rotating about its center line while the air intake channel 33 remains stationary. The specific rotatable connection can employ conventional techniques in the art and is not the focus of this invention.

[0131] In some specific embodiments, the rotating ash basin 2 includes an ash basin body 21 and a rotating mechanism 22 installed at the bottom of the ash basin body 21 and causing it to rotate.

[0132] In some specific embodiments, the ash basin body 21 is an annular basin that is wider at the top and narrower at the bottom, the base 31 of the rotary grate tower 3 is an annular structure base, and the air inlet channel 33 passes through the hollow part in the center of the ash basin body 21 and the base 31 and is connected to the conical grate 32.

[0133] In some specific embodiments, the ash basin body 21 is fixedly connected to the base 31 of the rotating grate tower 3 and rotates synchronously.

[0134] In some specific embodiments, the ash basin body 21 rotates around its own central axis.

[0135] In some specific embodiments, the rotating mechanism 22 adopts a conventional structure in the art, which only needs to realize the rotation of the ash basin body 21 around its own central axis. This is not the focus of the present invention, so it will not be described in detail.

[0136] A method for removing ash and slag from a fixed-bed biomass gasifier, which is implemented using any of the aforementioned ash and slag removal devices.

[0137] In some specific implementations, the steps of the ash and slag removal method include:

[0138] S1. The rotating ash basin 2 and the rotating grate tower 3 rotate synchronously, driving several ash scrapers 51 to rotate, and the ash and water from the gasification process fall into the slag chute 4.

[0139] S2. The rotating ash and water form a relative motion with the small ash knife 52 and the large ash knife 53. The small ash knife 52 guides the rotating ash and water to move in an orderly manner in the same direction.

[0140] S3 and the large ash cutter 53 intercept the ash residue, causing it to accumulate at the ash outlet 41 and be discharged.

[0141] Each of the above implementation methods can be implemented individually or in any combination of two or more.

[0142] The following description uses specific examples to illustrate the point.

[0143] Example 1

[0144] A slag removal device for a fixed-bed biomass gasifier, such as Figure 1 and 2 As shown, it includes:

[0145] A rotating ash basin 2 is located at the bottom of the gasifier body 1 but does not contact it;

[0146] A rotating grate tower 3 is installed inside the rotating ash basin 2 and rotates synchronously therewith. The top of the rotating grate tower 3 extends into the furnace body 1 and the bottom is connected to the ventilation system.

[0147] The slag chute 4, located between the inner wall of the rotating ash basin 2 and the rotating grate tower 3 and used to collect ash and slag, has an ash outlet 41 on its side wall for discharging ash and slag.

[0148] And the ash removal assembly 5, which includes a plurality of ash scrapers 51 installed on the outer wall of the rotary grate tower 3, a plurality of small ash scrapers 52 installed on the bottom of the furnace body 1, and a large ash scraper 53 installed on the outer wall of the furnace body 1.

[0149] In this embodiment, during the biomass gasification process, a large amount of ash, carbon slag, and a certain amount of water are generated and collect in the slag chute 4 between the inner wall of the rotating ash basin 2 and the rotating grate tower 3. The water can rapidly reduce the high temperature during ash discharge, preventing thermal damage to the equipment and extending its service life. Furthermore, the buffering properties of water can effectively reduce the impact force of falling ash, reducing equipment wear and tear and lowering maintenance costs.

[0150] In this embodiment, the furnace body 1 is cylindrical, with its top connected and supported by an external structure, and its bottom having a certain distance from the rotating ash basin 2, thus creating a suspended effect for the furnace body 1.

[0151] In this embodiment, the scraper blade 52 has a conical structure, and its circular bottom is connected to the outer wall of the rotating grate tower 3.

[0152] Two scraper blades 52 are provided, which are symmetrically distributed on both sides of the rotary grate tower 3.

[0153] In this embodiment, as Figures 1-3 As shown, the small ash shavings 52 have a sheet-like structure with a gradually decreasing thickness. The end of the small ash shavings 52 furthest from the rotating grate tower 3 has the greatest thickness, while the end closest to the rotating grate tower 3 has the smallest thickness. In other words, the tip of the small ash shavings 52 faces inward.

[0154] In this embodiment, the cross-sectional shape of the small ash cutter 52 is the same at any height. The cross-section is a curved-side triangle, which is a closed figure formed by the first arc 521, the first straight line 522, and the second straight line 523. The thickness of the small ash cutter 52 represents the length of any arc parallel to the first arc 521 between the first straight line 522 and the second straight line 523.

[0155] In this embodiment, the first arc 521 has the same curvature as the side wall of the furnace body 1 and is located directly below the side wall of the furnace body 1; the tangential angle between the arc edge of the first arc 521 and the first straight line 522 is 25°, the tangential angle between the arc edge of the first arc 521 and the second straight line 523 is 138°, and the vertex angle between the first straight line 522 and the second straight line 523 is 17°. The tangential angle between the arc edge of the first arc 521 and the first straight line 522 is defined at the connection point of the first arc 521 and the first straight line 522, taking the angle formed by the tangent direction of the first arc 521 and the first straight line 522. The tangential angle between the arc edge of the first arc 521 and the second straight line 523 is defined at the connection point of the first arc 521 and the second straight line 523, taking the angle formed by the tangent direction of the first arc 521 and the second straight line 523. The vertex angle of the first straight line 522 and the second straight line 523 is the angle between the first straight line 522 and the second straight line 523 at the connection point. The direction of the vertex angle of the first straight line 522 and the second straight line 523 is consistent with the rotation direction of the rotating ash basin 2.

[0156] In this embodiment, the ratio of the first arc 521 of the small gray knife 52 to the height of the small gray knife 52 is 1.35.

[0157] In this embodiment, five small ash knives 52 are provided, which are distributed at equal intervals around the bottom edge of the furnace body 1, and the shape, size and direction of the small ash knives 52 are consistent.

[0158] In this embodiment, as Figure 2 , 4 As shown in Figure 5, the large ash scalpel 53 is a sheet-like structure that is inclined from top to bottom on the outer side wall of the furnace body 1, and its width decreases gradually from top to bottom;

[0159] The length ratio of the widest to the narrowest point of the large ash shovel 53 is 3.5; the ratio of the widest point to the vertical height is 1. The width of the large ash shovel 53 is expressed as the distance along the radial direction from the outer wall of the furnace body 1 to the boundary line of the large ash shovel 53.

[0160] In this embodiment, the tilt angle of the large ash shovel 53 is 30°, which represents the angle between the connecting line of the large ash shovel 53 and the furnace body 1 and the vertical line.

[0161] In this embodiment, the side of the large ash shovel 53 that connects to the outer wall of the furnace body 1 is arc-shaped, and the side that is away from the outer wall of the furnace body 1 is arc-shaped, with different curvatures between the two arcs.

[0162] In this embodiment, the large ash cutter 53 has a planar structure.

[0163] In this embodiment, the horizontal center lines of the putty scraper 51, small putty scraper 52, and large putty scraper 53 are not at the same height, and the height of their horizontal center lines is: putty scraper 51 > large putty scraper 53 > small putty scraper 52.

[0164] In this embodiment, the furnace body 1 and the rotating grate tower 2 are coaxial cylindrical structures. The center points of the ash scraper 51, small ash scraper 52 and large ash scraper 53 along the circumference projection of the furnace body 1 are not located on the same radial line, and the positions of the ash scraper, small ash scraper and large ash scraper are staggered.

[0165] In this embodiment, the rotating grate tower 3 includes:

[0166] A base 31 is installed inside the ash basin 2 and connected and fixed thereto;

[0167] A conical grate 32 is mounted on the base 31;

[0168] And an air inlet channel 33 connected to the conical grate 32 and used for ventilation.

[0169] In this embodiment, the scraper blade 51 is disposed on the side wall of the base 31.

[0170] In this embodiment, the base 31 is a cylindrical structure.

[0171] In this embodiment, the air intake channel 33 and the air intake vent 323 are rotatably connected. The air intake vent 323 rotates about its center line, while the air intake channel 33 remains stationary. The specific rotatable connection can employ conventional techniques in the art and is not the focus of this invention.

[0172] In this embodiment, the rotary grate tower 3, as a key component of the gasifier, is made of high-temperature resistant and high-strength alloy material stainless steel 310S. The surface is specially treated to enhance wear resistance and corrosion resistance, and can withstand the high temperature and chemical erosion during the biomass gasification process.

[0173] In this embodiment, the rotating ash basin 2 includes an ash basin body 21 and a rotating mechanism 22 installed at the bottom of the ash basin body 21 and causing it to rotate.

[0174] In this embodiment, the ash basin body 21 is an annular basin that is wider at the top and narrower at the bottom, and the top is not closed; the base 31 of the rotating grate tower 3 is an annular structure base, and the air inlet channel 33 passes through the hollow part in the center of the ash basin body 21 and the base 31 and is connected to the conical grate 32.

[0175] In this embodiment, the ash basin body 21 is fixedly connected to the base 31 of the rotating grate tower 3 and rotates synchronously.

[0176] In this embodiment, the ash basin body 21 rotates around its own central axis, and the rotating mechanism 22 adopts a conventional structure in the art, which can drive the ash basin body 21 to rotate around its own central axis. It can refer to the structure of a cone-shaped rotary grate of a shoemaking waste incinerator disclosed in patent publication number CN111947159A.

[0177] A method for removing ash and slag from a fixed-bed biomass gasifier, which is implemented using the aforementioned ash and slag removal device, includes the following steps:

[0178] S1. The rotating ash basin 2 and the rotating grate tower 3 rotate synchronously, driving several ash scrapers 51 to rotate, and the ash and water from the gasification process fall into the slag chute 4.

[0179] S2. The rotating ash and water form a relative motion with the small ash knife 52 and the large ash knife 53. The small ash knife 52 guides the rotating ash and water to move in an orderly manner in the same direction.

[0180] S3 and the large ash cutter 53 intercept the ash residue, causing it to accumulate at the ash outlet 41 and be discharged.

[0181] In this embodiment, the working process and principle of the ash and slag removal device of the gasifier are as follows:

[0182] The rotating ash basin 2 rotates slowly at a preset speed. The rotation of the rotating ash basin 2 and the rotating grate tower 3 drives the rotation of several scraper blades 51 located on the outer wall of the rotating grate tower 3. During the operation of the rotating grate tower 3, this compacts the ash and slag accumulated in the furnace body 1 downwards. A certain amount of water generated during biomass gasification collects in the slag chute 4 between the inner wall of the rotating ash basin 2 and the rotating grate tower 3, rotating along with the rotating ash basin 2. Since the furnace body 1 is stationary, the small scraper blades 52 located at the bottom of the furnace body 1 are stationary, as are the large scraper blades 53 located on the outer wall of the furnace body 1. The rotating ash and water move relative to the small and large scraper blades 52 and 53. The small scraper blades 52 guide the rotating ash and water to move in the same direction in an orderly manner, promoting continuous flow of ash and slag and preventing localized accumulation. When the rotating ash reaches the large ash scraper 53, the largest surface of the large ash scraper 53 contacts the ash, which can intercept part of the ash and cause it to accumulate at the ash outlet 41. When the ash accumulates to a certain extent, it is discharged from the ash outlet 41, avoiding the ash from piling up randomly in the slag chute 4, reducing the difficulty of cleaning, and providing great convenience for subsequent ash collection and treatment. The small ash scraper 41 can be used to process finer ash, while the large ash scraper 53 can process larger ash. Because the scraper 51, small ash scraper 52, and large ash scraper 53 have different shapes, heights, and radial positions, they can form a multi-layered slag discharge structure, enhancing the slag discharge capacity. The different shapes may affect the cutting and pushing efficiency, the different heights may control the thickness of the slag layer, and the different radial positions may cover different areas, ensuring comprehensive slag discharge.

[0183] Example 2

[0184] In this embodiment, as Figure 6 and 7 As shown, the large ash shavings 53 are equipped with an ash discharge baffle 531 that is attached to the baffle and extends beyond the width of the large ash shavings 53 at one end. This baffle concentrates the ash and slag, allowing it to reach a certain amount before automatically discharging it through the ash discharge port 41.

[0185] In this embodiment, looking from bottom to top along a vertical line, with the lowest point of the large ash shovel 53 as the starting point, the ash discharge baffle 531 is located at 80% of the height of the large ash shovel 53.

[0186] In this embodiment, the width of the ash discharge baffle 531 is 1.2 times the maximum width of the large ash scalpel 53.

[0187] Example 3

[0188] like Figure 8 and 9As shown, most aspects are the same as in Embodiment 2, except that in this embodiment, the conical grate 32 is topped with a conical cap 321 pointing upwards. The cap 321 has several air outlets, each with a spray mask 322 above it. These air outlets ensure uniform air distribution during gasification, promoting complete combustion of biomass and reducing the content of unburned materials in the ash. The spray mask 322 has a raised structure, significantly increasing the friction surface area of ​​the conical grate 32. When primary air is introduced into the furnace, the spray mask 322 guides the airflow to fully contact the material, achieving uniform combustion. Simultaneously, the spray mask 322 alters the airflow trajectory within the furnace, indirectly increasing fluid turbulence and resulting in a more uniform thickness of material spread on the grate, ensuring smooth ash fall. In this embodiment, several air outlets form concentric ring arrays centered on the tip of the cap 321, with each array arranged radially at intervals.

[0189] In this embodiment, the bottom of the conical grate 32 is a frustum-shaped air inlet 323, wider at the top and narrower at the bottom, which is connected to the air inlet channel 33. Air enters through the air inlet channel 33 and reaches the top cover 321 of the rotary grate tower 3 via the air inlet 323. The incoming air is ambient temperature cold air, which can cool the equipment. Therefore, with the protection of cold air, the air inlet channel 33 and the conical grate 32 will not cause the rotary grate tower 3 to deform or be damaged due to high temperature.

[0190] Example 4

[0191] Compared to Example 3, most aspects are the same, except that the gasifier also includes an ash separation and collection assembly 6 for separating and collecting ash discharged from the ash outlet 41, such as... Figure 10 As shown, it includes:

[0192] Ash discharge chute 61 with screen 6111;

[0193] Small volume ash collector 62 for collecting small volume ash slag that falls from the screen 6111;

[0194] And a large volume ash collector 63 for collecting large volumes of ash discharged from the ash discharge trough 61.

[0195] In this embodiment, as Figure 11 As shown, the ash discharge trough 61 includes a bottom surface 611 with a screen 6111 and side baffles 612 disposed on both sides of the bottom surface.

[0196] In this embodiment, the bottom surface 611 has a structure that is wider at the top and narrower at the bottom, and the ash discharge trough 61 is inclined, which helps the ash slag to slide down naturally under its own weight.

[0197] In this embodiment, the ash discharge trough 61 is not connected to the rotating ash basin 2, but is connected and supported by an external steel frame. The external steel frame is a support structure, which is a conventional structure in the art, and is used to support the ash discharge trough 61.

[0198] In this embodiment, an ash discharge baffle is also provided at the ash discharge port 41.

[0199] In this embodiment, the ash slag discharged from the ash outlet 41 enters the ash outlet 61. According to the particle size of the ash slag, the smaller ash slag is accurately screened out by the screen 6111. The screened ash slag falls into the small volume ash slag collector 62 below. The large volume ash slag that is not filtered out by the screen 6111 is discharged from the bottom of the ash outlet 61 and reaches the large volume ash slag collector 63. This is conducive to the centralized collection of large and small volume ash slag, laying the foundation for subsequent resource recycling and treatment.

[0200] Example 5

[0201] Compared with Example 4, most of them are the same, except that the scraper blade 52 is a cylindrical structure, and its circular bottom is connected to the outer wall of the rotating grate tower 3.

[0202] Example 6

[0203] Compared with Embodiment 4, most of them are the same, except that the arc tangent angle between the first arc 521 and the first straight line 522 is 20°, the arc tangent angle between the first arc 521 and the second straight line 523 is 140°, and the vertex angle between the first straight line 522 and the second straight line 523 is 20°.

[0204] Example 7

[0205] Compared to Example 4, most aspects are the same, except that the tangential angle between the first arc 521 and the first straight line 522 of the small ash cutter 52 is 30°, the tangential angle between the first arc 521 and the second straight line 523 is 135°, and the vertex angle between the first straight line 522 and the second straight line 523 is 15°. The ratio of the first arc 521 of the small ash cutter 52 to the height of the small ash cutter 52 is 1.15.

[0206] Example 8

[0207] Compared to Embodiment 4, most aspects are the same, except that the tangential angle between the first arc 521 and the first straight line 522 of the small ash cutter 52 is 23.4°, the tangential angle between the first arc 521 and the second straight line 523 is 138°, and the vertex angle between the first straight line 522 and the second straight line 523 is 18°. The ratio of the first arc 521 of the small ash cutter 52 to the height of the small ash cutter 52 is 1.36.

[0208] Example 9

[0209] Most of them are the same as in Example 4, except that the tilt angle of the large ash cutter 53 is 25°.

[0210] Example 10

[0211] Most of them are the same as in Example 4, except that the tilt angle of the large ash cutter 53 is 40°.

[0212] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A ash and slag removal device for a fixed-bed biomass gasification furnace, characterized in that, include: A rotating ash basin (2) is located at the bottom of the furnace body (1) of the gasifier and is not in contact with it. A rotating grate tower (3) is installed inside the rotating ash basin (2) and rotates synchronously therewith. The top of the rotating grate tower (3) extends into the furnace body (1) and the bottom is connected to the ventilation system. The slag chute (4) located between the inner wall of the rotating ash basin (2) and the rotating grate tower (3) and used to collect ash slag has an ash outlet (41) on its side wall to discharge ash slag. And the ash removal assembly (5), which includes a plurality of ash scrapers (51) installed on the outer wall of the rotary grate tower (3), a plurality of small ash scrapers (52) installed at the bottom of the furnace body (1), and a large ash scraper (53) installed on the outer wall of the furnace body (1). The small ash knife (52) has a sheet-like structure with a gradually decreasing thickness. The end of the small ash knife (52) furthest from the rotating grate tower (3) has the greatest thickness, and the end closest to the rotating grate tower (3) has the smallest thickness. The cross-sectional shape of the small ash knife (52) at any height is the same. The cross-sectional shape is an arc-sided triangle, which is a closed figure composed of a first arc (521), a first straight line (522), and a second straight line (523). The apex angle direction of the first straight line (522) and the second straight line (523) is consistent with the rotation direction of the rotating ash basin. The large ash shovel (53) is a sheet-like structure that is inclined from top to bottom on the outer wall of the furnace body (1). Its width decreases gradually from top to bottom. The large ash shovel (53) is provided with an ash discharge baffle (531) that is attached to it and has one end that extends beyond the width of the large ash shovel (53). The length ratio of the widest part of the large ash shovel to the narrowest part is 2 to 6. The inclination angle of the large ash shovel is 25° to 40°. The horizontal center lines of the scraper (51), small scraper (52), and large scraper (53) are not at the same height, and the height of their horizontal center lines is scraper > large scraper > small scraper; the center points of the scraper (51), small scraper (52), and large scraper (53) along the circumference projection of the furnace body (1) are not on the same radial line.

2. The ash and slag removal device for a fixed-bed biomass gasification furnace according to claim 1, characterized in that, The scraper blade (51) includes a conical structure and a cylindrical structure, and its circular bottom is connected to the outer wall of the rotating grate tower (3). Two scraper blades (51) are provided, which are symmetrically distributed on both sides of the rotary grate tower (3).

3. The ash and slag removal device for a fixed-bed biomass gasification furnace according to claim 1, characterized in that, There are 4 to 8 small ash knives (52), which are distributed at equal intervals around the bottom edge of the furnace body (1), and the shape, size and direction of the small ash knives (52) are consistent.

4. The ash and slag removal device for a fixed-bed biomass gasification furnace according to claim 1, characterized in that, The ash discharge device of the gasifier further includes an ash separation and collection assembly (6) for separating and collecting the ash discharged from the ash outlet (41), which includes: Ash discharge chute (61) with screen (6111); Small volume ash collector (62) for collecting small volume ash slag that falls from the screen (6111). And a large volume ash collector (63) for collecting large volume ash slag discharged from the ash discharge trough (61).

5. A method for removing ash and slag from a fixed-bed biomass gasification furnace, characterized in that, It is implemented using the ash and slag removal device described in any one of claims 1 to 4.

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