Ash discharging device and method for fixed bed biomass gasifier

Abstract

The invention relates to an ash discharging device and method for a fixed bed biomass gasification furnace. The ash discharging device comprises a furnace body; the rotary ash basin is arranged at the bottom of the furnace body and is not in contact with the furnace body; the rotary grate tower is arranged in the rotary ash basin and rotates synchronously with the rotary ash basin, the top of the rotary grate tower extends into the furnace body, and the bottom of the rotary grate tower is connected with a ventilation system; the slag chute is positioned between the inner wall of the rotary ash basin and the rotary grate tower and is used for collecting ash slag, and an ash outlet for discharging the ash slag is formed in the side wall of the slag chute; and the ash discharging assembly comprises a plurality of ash scraping knives mounted on the outer side wall of the rotary grate tower, a plurality of small ash knives mounted at the bottom of the furnace body and a large ash knife mounted on the outer side wall of the furnace body. Compared with the prior art, the problem of ash blockage can be effectively avoided, the slag discharging efficiency is improved, ash can be directly discharged to an external designated position, and powerful support is provided for efficient utilization of biomass energy.

Description

Technical Field

[0001] The invention relates to the technical field of ash discharge of a biomass gasifier, and in particular to an ash and slag discharge device and method of a fixed-bed biomass gasifier. Background Art

[0002] Biomass gasification is a thermochemical process that uses a gasifying agent (air, oxygen or water vapor, etc.) to promote the pyrolysis, oxidation, reduction and reforming of polymers such as carbon and hydrogen in the biomass under certain thermal conditions, and finally turns them into small molecular hydrocarbons. After a series of chemical reactions, the biomass material becomes a combustible gas, which is directly discharged into the boiler for combustion, and the ash after combustion and cracking will be discharged from the furnace body. The slag of the current gasifier can be discharged manually or mechanically. Manual slag discharge uses a shovel or other tool to scoop the slag in the furnace out of the slag bucket, and then collects and processes it in a centralized manner. This method is simple to operate, but the work intensity is high. Mechanical slag discharge mostly uses a screw conveyor to discharge the slag at the bottom, but if the slag is in block form, it is easy to cause the slag discharger to get stuck or damaged.

[0003] Patent publication number CN105737164A discloses a garbage pyrolysis gasification furnace, in which the base of the furnace body is set in an ash pan; a scraper is welded on the ash pan, and the ash pan is driven to rotate by a motor, and the ash entering the ash pan is taken out by the scraper, and two rows of small air holes are provided on both sides of the scraper. However, the ash pan of the pyrolysis gasification furnace rotates to discharge ash, and the ash can only be discharged into the ash basin. The ash discharge efficiency is slow, and it cannot be discharged to a designated external location, and manual slag discharge is required. In addition, if the ash melts at high temperature to form a hard lump, the scraper may not be able to effectively take it out, resulting in poor slag discharge or even equipment jamming. Summary of the invention

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

[0005] The purpose of the present invention can be achieved by the following technical solutions:

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

[0007] A rotating ash basin disposed at the bottom of the furnace body of the gasifier and not in contact with the furnace body;

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

[0009] A slag chute located between the inner wall of the rotary ash pan and the rotary grate tower and used for collecting slag, and an ash discharge port for discharging slag is arranged on the side wall thereof;

[0010] And an ash discharging assembly, which includes a plurality of scraping knives installed on the outer side wall of the rotary grate tower, a plurality of small ash knives installed at the bottom of the furnace body, and a large ash knife installed on the outer side wall of the furnace body.

[0011] Further, the furnace body is in a cylindrical shape, its top is connected and supported by an external structure, and there is a certain distance between its bottom and the rotary ash pan, forming the effect of the suspension of the furnace body.

[0012] Further, the scraping knife includes a conical structure and a cylindrical structure, and its circular bottom is connected to the outer side wall of the rotary grate tower;

[0013] There are two scraping knives, which are symmetrically distributed on both sides of the rotary grate tower.

[0014] Further, the small ash knife is in a sheet structure, and its thickness decreases in a gradient manner. Among them, the thickness of the small ash knife is the largest at the end far from the rotary grate tower and the smallest at the end close to the rotary grate tower. That is to say, the tip of the small ash knife faces inward.

[0015] Furthermore, the cross-sectional shape of the small ash knife at any height is the same, and the cross-section is in the shape of an arc-edge triangle, which is a closed figure composed of a first arc, a first straight line, and a second straight line. The thickness of the small ash knife represents the length of any arc parallel to the first arc between the first straight line and the second straight line.

[0016] Furthermore, the first arc is consistent with the side wall radian of the furnace body and the first arc 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 straight line and the second straight line is 15° - 20°. The tangential angle between the first arc and the first straight line means the included angle formed by taking the tangent direction of the first arc and the first straight line at the connection point of the first arc and the first straight line. The tangential angle between the first arc and the second straight line means the included angle formed by taking the tangent direction of the first arc and the second straight line at the connection point of the first arc and the second straight line. The vertex angle between the first straight line and the second straight line is the included angle between the first straight line and the second straight line at the connection point. The vertex angle direction between the first straight line and the second straight line is consistent with the rotation direction of the rotary ash pan

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

[0019] Further, there are 4 to 8 small grey knives, which are evenly distributed in a circle along the bottom edge of the furnace body, and the shapes, sizes, and directions of the small grey knives are the same.

[0020] Further, the large grey knife is a sheet-like structure inclined from top to bottom on the outer side wall of the furnace body, and its width decreases in a gradient from top to bottom.

[0021] Furthermore, the length ratio of the maximum width to the minimum width of the large grey knife is 2 to 6, preferably 3 to 4; the ratio of the maximum width to the vertical height is 0.2 to 2, preferably 0.5 to 1.5. The width of the large grey knife is expressed as the distance along the radial direction from the outer side wall of the furnace body to the boundary line of the large grey knife.

[0022] Furthermore, the inclination angle of the large grey knife is 25° to 40°, and the inclination angle represents the angle between the connecting line of the large grey knife and the furnace body and the vertical line.

[0023] Furthermore, one side of the large grey knife connected to the outer side wall of the furnace body is arc-shaped, and the side away from the outer side wall of the furnace body is arc-shaped, and the radian of the two arcs is different.

[0024] Furthermore, the large grey knife is a planar structure or a curved surface structure.

[0025] Further, an ash discharge baffle is arranged on the large grey knife, which is attached to the large grey knife and one end exceeds the width of the large grey knife.

[0026] Furthermore, when looking from bottom to top along the vertical line, starting from the lowest point of the large grey knife, the ash discharge baffle is located at 50% to 80% of the height of the large grey knife.

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

[0028] Further, the horizontal center lines of the ash scraping knife, the small grey knife, and the large grey knife are not at the same height.

[0029] Furthermore, the height of its horizontal center line is ash scraping knife > large grey knife > small grey knife.

[0030] Further, the furnace body and the rotary grate tower are coaxial cylindrical structures, and the central points of the circumferential projections of the ash scraping knife, the small grey knife, and the large grey knife on the furnace body are not on the same radial line, and the positions of the ash scraping knife, the small grey knife, and the large grey knife are staggered from each other.

[0031] Furthermore, the ash and slag discharging 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] An ash outlet trough with a screen;

[0033] A small-volume ash and slag collector for collecting the small-volume ash and slag falling from the screen;

[0034] And a large-volume ash and slag collector for collecting the large-volume ash and slag discharged from the ash outlet trough.

[0035] Furthermore, the ash outlet trough includes a bottom surface with a screen and side baffles arranged 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 outlet trough is not connected to the rotary ash pan and 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 outlet trough.

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

[0039] Furthermore, an ash outlet baffle is also arranged at the ash outlet.

[0040] Furthermore, the rotary grate tower includes:

[0041] A base arranged in and fixedly connected to the ash pan;

[0042] A conical grate installed on the base;

[0043] And an air inlet passage connected to the conical grate and used for ventilating.

[0044] Furthermore, the ash scraping knife is arranged on the side wall of the base.

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

[0046] Furthermore, a conical top cover with the tip facing upward is arranged at the top of the conical grate. A plurality of air outlet openings are arranged on the top cover, and a spray mask is arranged above each air outlet opening. The spray mask protects the air outlet openings from being blocked by materials, changes the direction of the air outlet, and at the same time, the convex structure of the spray mask can also increase the disturbance in the furnace to make the material spread more evenly.

[0047] Furthermore, a plurality of the air outlet openings form a plurality of concentric annular arrays with the tip of the top cover as the center, and each array is arranged at intervals along the radial direction.

[0048] Furthermore, the bottom of the conical grate is a frustum-shaped air inlet flare that is wider at the top and narrower at the bottom, and the top is not closed; the frustum-shaped air inlet flare is connected to the air inlet passage. Air enters from the air inlet passage and reaches the top cover of the rotary grate tower via the air inlet flare. The entering air is normal temperature cold air, which can cool the equipment. Therefore, the air inlet passage and the conical grate will not cause the rotary grate tower to deform and be damaged due to high temperature under the protection of cold air.

[0049] Furthermore, the air inlet passage is rotatably connected to the air inlet flare. The air inlet flare rotates around the center line, and the air inlet passage is stationary. The specific rotatable connection can adopt conventional technical means in the art, which is not the focus of the present invention.

[0050] Further, the rotary ash pan includes an ash pan body and a rotary mechanism installed at the bottom of the ash pan body to make it rotate.

[0051] Furthermore, the ash pan body is an annular pan that is wider at the top and narrower at the bottom, the base of the rotary grate tower is an annular structure base, and the air inlet passage passes through the hollow parts at the centers of the ash pan body and the base and is connected to the conical grate.

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

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

[0054] Furthermore, the rotary mechanism adopts a conventional structure in the art. It only needs to realize the rotation of the ash pan body around its own central axis, which is not the focus of the present invention, so it will not be elaborated here.

[0055] On the other hand, the present invention also provides an ash and slag discharging method for a fixed-bed biomass gasifier, which is implemented by using any one of the ash and slag discharging devices.

[0056] Further, the steps of the ash and slag discharging method include:

[0057] S1. The rotary ash pan and the rotary grate tower rotate synchronously, driving several ash scraping knives to rotate, and the ash and slag and water during the gasification process fall into the slag chute;

[0058] S2. The rotating ash and slag and water form a relative movement with the small ash knives and the large ash knives, and the small ash knives guide the rotating ash and slag and water to move orderly in the same direction;

[0059] S3. The large ash knives intercept the ash and slag, making it accumulate at the ash outlet and be discharged.

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

[0061] (1) Through the provision of the ash scraping knife, small ash knife, and large ash knife, the ash scraping knife is used to generally handle ash residue, the small ash knife is used to handle finer ash residue, and the large ash knife is used to handle larger ash residue, forming a reasonable and functionally complete slag discharging system, greatly improving the slag discharging efficiency. In addition, the provision of the ash scraping knife, small ash knife, and large ash knife also extends the service life of the ash scraping knife, small ash knife, and large ash knife, reduces the frequency of shutdown for maintenance, and is conducive to improving the slag discharging efficiency.

[0062] (2) By setting the ash scraping knife, small ash knife, and large ash knife to have different shapes, different heights, and different radial positions, a multi-level slag discharging structure can be formed to enhance the slag discharging ability. Different shapes may affect the cutting and pushing efficiency, different heights may control the thickness of the slag layer, and different radial positions may cover different areas to ensure comprehensive slag discharging.

[0063] (3) In the present invention, the small ash knife is a sheet-like structure, and its thickness decreases in a gradient manner. Among them, the thickness of the small ash knife is the largest at the end far from the rotary grate tower and the smallest at the end close to the rotary grate tower. The cross-sectional shape of the small ash knife at any height is the same, and the cross-section is an arc-edge triangle shape. The vertex angle directions of the first straight line and the second straight line are consistent with the rotation direction of the rotary ash pan, forcing the ash residue to flow along the set path and avoiding blockage caused by disorderly accumulation. Moreover, the sharp vertex of the arc triangle can pierce into the coking mass, and the arc-shaped edge provides a shearing force to achieve secondary crushing of large slag materials. A number of small ash knives arranged at equal intervals ensure uniform distribution of the slag discharging force in the circumferential direction, avoiding excessive thickness of the local slag layer and affecting the heat balance of the gasifier.

[0064] (4) The large ash knife of the present invention is inclined. When the rotating ash residue rotates to the position of the large ash knife, the largest surface of the large ash knife contacts the ash residue, which can achieve the interception of part of the ash residue, causing it to accumulate at the ash discharging port. When the accumulation amount of the ash residue reaches a certain level, it is discharged from the ash discharging port, avoiding the disorderly accumulation of ash residue in the slag chute, reducing the cleaning difficulty, and providing great convenience for the subsequent collection and treatment of ash residue.

[0065] (5) By setting up an ash residue separation and collection assembly, the ash residue discharged from the ash discharging port enters the ash discharging chute. According to the particle size of the ash residue, the smaller-volume ash residue is accurately screened out through the sieve mesh, and the screened ash residue falls into the small-volume ash residue collector below. The large-volume ash residue that is not filtered by the sieve mesh is discharged from the bottom of the ash discharging chute and reaches the large-volume ash residue collector, which is conducive to the centralized collection of large- and small-volume ash residue and lays a foundation for subsequent resource recovery and treatment. Description of the Drawings

[0066] Figure 1 It is a schematic structural diagram of the gasifier shown in Embodiment 1;

[0067] Figure 2Top view of the gasifier shown in Embodiment 1;

[0068] Figure 3 Structural schematic diagram of the small ash knife shown in Embodiment 1;

[0069] Figure 4 Structural schematic diagram of the large ash knife shown in Embodiment 1;

[0070] Figure 5 Side view (ash discharge port direction) of the gasifier shown in Embodiment 1;

[0071] Figure 6 Top view of the gasifier shown in Embodiment 2;

[0072] Figure 7 Structural schematic diagram of the large ash knife with an ash discharge baffle shown in Embodiment 2.

[0073] Figure 8 Structural schematic diagram of the conical grate shown in Embodiment 3;

[0074] Figure 9 Top view of the conical grate shown in Embodiment 3;

[0075] Figure 10 Structural schematic diagram of the gasifier shown in Embodiment 4;

[0076] Figure 11 Structural schematic diagram of the ash discharge trough shown in Embodiment 4.

[0077] Explanation of the markings in the figure:

[0078] 1 - furnace body;

[0079] 2 - rotating ash pan, 21 - ash pan 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 discharge port;

[0082] 5 - ash discharge assembly, 51 - scraping knife, 52 - small ash knife, 521 - first arc, 522 - first straight line, 523 - second straight line, 53 - large ash knife, 531 - ash discharge baffle;

[0083] 6 - ash and slag separation and collection assembly, 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 manners

[0084] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments are implemented on the premise of the technical solution of the present invention, and the detailed implementation manners and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments. In the following embodiments or implementation manners, if there is no special description of functional components or structures, it means that they are all conventional components or conventional structures adopted in the art to achieve the corresponding functions.

[0085] It should be noted that in the description of the present invention, the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "front end", "rear end", "both ends", "one end", "the other end", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0086] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0087] An ash discharging device for a fixed-bed biomass gasifier, comprising:

[0088] A rotating ash pan 2 disposed at the bottom of the furnace body 1 of the gasifier and not in contact with it;

[0089] A rotating grate tower 3 disposed in the rotating ash pan 2 and rotating synchronously with it. The top of the rotating grate tower 3 extends into the furnace body 1, and the bottom is connected to a ventilation system;

[0090] A slag chute 4 located between the inner wall of the rotating ash pan 2 and the rotating grate tower 3 and used for collecting ash and slag. The side wall of the slag chute 4 is provided with an ash discharge port 41 for discharging ash and slag;

[0091] And an ash discharging assembly 5, which includes a plurality of ash scraping knives 51 installed on the outer side wall of the rotating grate tower 3, a plurality of small ash knives 52 installed at the bottom of the furnace body 1, and a large ash knife 53 installed on the outer side wall of the furnace body 1.

[0092] In some specific embodiments, the furnace body 1 is in a cylindrical shape, its top is connected and supported by an external structure, and there is a certain distance between its bottom and the rotary ash pan 2, forming the effect of suspension of the furnace body 1.

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

[0094] There are two ash scrapers 51, which are symmetrically distributed on both sides of the rotary grate tower 3.

[0095] In some specific embodiments, the small ash knife 52 is in a sheet structure, and its thickness decreases in a gradient manner. Among them, the thickness of the small ash knife 52 is the largest at the end far from the rotary grate tower 3 and the smallest at the end close to the rotary grate tower 3. That is to say, the tip of the small ash knife 52 faces inward.

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

[0097] In some specific embodiments, the first arc 521 is consistent with the side wall radian 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 first arc 521 and the first straight line 522 is 20° - 30°, the tangential angle between 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 first arc 521 and the first straight line 522 means that at the connection point of the first arc 521 and the first straight line 522, the included angle formed by taking the tangent direction of the first arc 521 and the first straight line 522. The tangential angle between the first arc 521 and the second straight line 523 means that at the connection point of the first arc 521 and the second straight line 523, the included angle formed by taking the tangent direction of the first arc 521 and the second straight line 523. The vertex angle between the first straight line 522 and the second straight line 523 is the included angle between the first straight line 522 and the second straight line 523 at the connection point. The vertex angle direction of the first straight line 522 and the second straight line 523 is consistent with the rotation direction of the rotary ash pan 2

[0099] In some specific embodiments, the ratio of the first arc 521 of the small ash knife 52 to the height of the small ash 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 evenly distributed in a circle along the bottom edge of the furnace body 1, and the shapes, sizes, and directions of the small ash knives 52 are the same.

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

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

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

[0104] In some specific embodiments, the side of the large ash knife 53 connected to the outer side wall of the furnace body 1 is arc-shaped, and the side away from the outer side wall of the furnace body 1 is arc-shaped, and the radian of the two arcs is different.

[0105] Furthermore, the large ash knife 53 is a planar structure or a curved surface structure.

[0106] In some specific embodiments, an ash discharge baffle 531 is provided on the large ash knife 53, which fits with it and one end extends beyond the width of the large ash knife 53.

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

[0109] In some specific embodiments, the horizontal centerlines of the ash scraping knife 51, the small ash knife 52, and the large ash knife 53 are not at the same height.

[0110] In some specific embodiments, the height of its horizontal centerline is ash scraping knife 51 > large ash knife 53 > small ash knife 52.

[0111] In some specific embodiments, the furnace body 1 and the rotary grate tower 2 are cylindrical structures arranged coaxially, and the central points of the circumferential projections of the ash scraping knives 51, the small ash knives 52, and the large ash knives 53 along the furnace body 1 are not located on the same radial line, and the positions of the ash scraping knives, the small ash knives, and the large ash knives are staggered from each other.

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

[0113] An ash discharging trough 61 with a screen 6111;

[0114] A small volume ash slag collector 62 for collecting the small volume ash slag falling from the screen 6111;

[0115] And a large volume ash slag collector 63 for collecting the large volume ash slag discharged from the ash discharging trough 61.

[0116] In some specific embodiments, the ash discharging trough 61 includes a bottom surface 611 with a screen 6111 and side baffles 612 arranged 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 discharging trough 61 is not connected to the rotary ash pan 2 and 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 discharging trough 61.

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

[0120] In some specific embodiments, an ash discharging baffle is further arranged at the ash outlet 41.

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

[0122] A base 31 arranged in and fixedly connected to the ash pan 2;

[0123] A conical grate 32 installed 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 ash scraping knife 51 is arranged on the side wall of the base 31.

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

[0127] In some specific embodiments, a conical top cover 321 with its tip facing upward is provided at the top of the conical grate 32. A plurality of air outlets are provided on the top cover 321, and a spray mask 322 is provided above each air outlet. The spray mask 322 protects the air outlets from being blocked by materials, changes the direction of the outgoing air, and at the same time, the protruding structure of the spray mask 322 can also increase the disturbance inside the furnace to make the material spread more evenly.

[0128] In some specific embodiments, a plurality of the air outlets form a plurality of concentric annular arrays with the tip of the top cover 321 as the center of the circle, and the arrays are 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 flare 323 that is wider at the top and narrower at the bottom, and the top is not closed; the frustum-shaped air inlet flare 323 is connected to the air inlet passage 33. Air enters from the air inlet passage 33 and reaches the top cover 321 of the rotary grate tower 3 via the air inlet flare 323. The incoming air is normal temperature cold air, which can cool the equipment. Therefore, the air inlet passage 33 and the conical grate 32 will not cause the rotary grate tower 3 to be deformed and damaged due to high temperature under the protection of cold air.

[0130] In some specific embodiments, the air inlet passage 33 is rotatably connected to the air inlet flare 323. The air inlet flare 323 rotates with the center line as the rotation center, and the air inlet passage 33 is stationary. The specific rotational connection can adopt conventional technical means in the art, which is not the focus of the present invention.

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

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

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

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

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

[0136] A method for discharging ash and slag from a fixed-bed biomass gasifier is implemented using any of the described ash and slag discharging devices.

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

[0138] S1. The rotary ash pan 2 and the rotary grate tower 3 rotate synchronously, driving a number of ash scraping knives 51 to rotate, and the ash and slag and water during the gasification process fall into the slag chute 4.

[0139] S2. The rotating ash and slag and water move relative to the small ash knives 52 and the large ash knives 53, and the small ash knives 52 guide the rotating ash and slag and water to move orderly in the same direction.

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

[0141] Each of the above embodiments can be implemented independently, or any two or more of them can be combined and implemented.

[0142] The following is illustrated with specific examples.

[0143] Example 1

[0144] An ash and slag discharging device for a fixed-bed biomass gasifier, as Figure 1 and 2 shown, includes:

[0145] A rotary ash pan 2 disposed at the bottom of the furnace body 1 of the gasifier and not in contact with it;

[0146] A rotary grate tower 3 disposed inside the rotary ash pan 2 and rotating synchronously with it, with the top of the rotary grate tower 3 extending into the furnace body 1 and the bottom connected to a ventilation system;

[0147] A slag chute 4 located between the inner wall of the rotary ash pan 2 and the rotary grate tower 3 and used for collecting ash and slag, and an ash outlet 41 for discharging ash and slag is provided on its side wall;

[0148] And an ash discharging assembly 5, which includes a number of ash scraping knives 51 installed on the outer side wall of the rotary grate tower 3, a number of small ash knives 52 installed at the bottom of the furnace body 1, and a large ash knife 53 installed on the outer side 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 generated converge in the slag chute 4 between the inner wall of the rotary ash pan 2 and the rotary grate tower 3. On the one hand, water can quickly reduce the high temperature during ash and slag discharge, avoid thermal damage to the equipment due to excessive temperature, and extend the service life of the equipment; on the other hand, the buffering characteristics of water can effectively reduce the impact force when the ash and slag fall, reduce the wear degree of the equipment, and reduce the maintenance cost.

[0150] In this embodiment, the furnace body 1 is in a cylindrical shape, its top is connected and supported by an external structure, and there is a certain distance between its bottom and the rotary ash pan 2, forming the effect of suspension of the furnace body 1.

[0151] In this embodiment, the ash scraper 52 is in a conical structure, and its circular bottom is connected to the outer side wall of the rotary grate tower 3;

[0152] There are two ash scrapers 52, which are symmetrically distributed on both sides of the rotary grate tower 3.

[0153] In this embodiment, as Figures 1 to 3 shown, the small ash knife 52 is in a sheet structure, and its thickness decreases in a gradient manner. Among them, the end of the small ash knife 52 far from the rotary grate tower 3 has the largest thickness, and the end close to the rotary grate tower 3 has the smallest thickness. That is to say, the tip of the small ash knife 52 faces inward.

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

[0155] In this embodiment, the first arc 521 is consistent with the side wall radian of the furnace body 1 and the first arc 521 is located directly below the side wall of the furnace body 1; the tangential angle between the first arc 521 and the first straight line 522 is 25°, 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 17°. The tangential angle between the first arc 521 and the first straight line 522 means that at the connection point of the first arc 521 and the first straight line 522, the included angle formed by taking the tangent direction of the first arc 521 and the first straight line 522. The tangential angle between the first arc 521 and the second straight line 523 means that at the connection point of the first arc 521 and the second straight line 523, the included angle formed by taking the tangent direction of the first arc 521 and the second straight line 523. The vertex angle between the first straight line 522 and the second straight line 523 is the included angle between the first straight line 522 and the second straight line 523 at the connection point. The vertex angle direction of the first straight line 522 and the second straight line 523 is consistent with the rotation direction of the rotary ash pan 2.

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

[0157] In this embodiment, there are 5 small ash knives 52, which are evenly distributed in a circle along the bottom edge of the furnace body 1, and the shapes, sizes, and directions of the small ash knives 52 are the same.

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

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

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

[0161] In this embodiment, the side of the large ash knife 53 connected to the outer side wall of the furnace body 1 is arc-shaped, and the side away from the outer side wall of the furnace body 1 is arc-shaped, and the radian of the two arcs is different.

[0162] In this embodiment, the large ash knife 53 is a planar structure.

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

[0164] In this embodiment, the furnace body 1 and the rotary grate tower 2 are coaxial cylindrical structures, and the central points of the circumferential projections of the ash scraping knife 51, the small ash knife 52, and the large ash knife 53 along the furnace body 1 are not on the same radial line, and the positions of the ash scraping knife, the small ash knife, and the large ash knife are staggered from each other.

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

[0166] A base 31 disposed in and fixedly connected to the ash pan 2;

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

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

[0169] In this embodiment, the ash scraping knife 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 intake channel 33 is rotatably connected to the air inlet flare 323. The air inlet flare 323 rotates around the center line, and the intake channel 33 remains stationary. The specific rotational connection can adopt conventional technical means in the art, which is not the focus of the present invention.

[0172] In this embodiment, the rotary grate tower 3, as a key component of the gasifier, is made of the heat-resistant and high-strength alloy material stainless steel 310S. Its surface has been 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 rotary ash pan 2 includes an ash pan body 21 and a rotary mechanism 22 installed at the bottom of the ash pan body 21 to make it rotate.

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

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

[0176] In this embodiment, the ash pan body 21 rotates around its own central axis. The rotary mechanism 22 adopts a conventional structure in the art and can drive the ash pan body 21 to rotate around its own central axis. It can refer to the structure of the conical disk type rotary grate of a shoe waste incinerator disclosed in the patent publication number CN111947159A.

[0177] A method for discharging ash and slag of a fixed-bed biomass gasifier is implemented by using the ash and slag discharging device described above. The steps of the ash and slag discharging method include:

[0178] S1. The rotary ash pan 2 and the rotary grate tower 3 rotate synchronously, driving a plurality of ash scraping knives 51 to rotate, and the ash and slag and water during the gasification process fall into the slag chute 4;

[0179] S2. The rotating ash and slag and water form a relative motion with the small ash knives 52 and the large ash knives 53, and the small ash knives 52 guide the rotating ash and slag and water to move orderly in the same direction;

[0180] S3. The large ash knives 53 intercept the ash and slag, 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 discharging device of the gasifier are as follows:

[0182] The rotating ash pan 2 rotates slowly at a preset speed. The rotating ash pan 2 and the rotating grate tower 3 rotate, driving a number of ash scraping knives 51 provided on the outer side wall of the rotating grate tower 3 to rotate. During the operation of the rotating grate tower 3, the ash and slag accumulated in the furnace body 1 can be compacted downward. During the biomass gasification process, a certain amount of water is generated and converges in the slag chute 4 between the inner wall of the rotating ash pan 2 and the rotating grate tower 3, and rotates with the rotation of the rotating ash pan 2. Since the furnace body 1 is stationary, the small ash knife 52 provided at the bottom of the furnace body 1 is stationary, and the large ash knife 53 provided on the outer side wall of the furnace body 1 is stationary. The rotating ash and slag, water and the small ash knife 52, large ash knife 53 form relative motion. The small ash knife 52 guides the rotating ash and slag, water to move orderly in the same direction, promotes the continuous flow of ash and slag, and avoids local accumulation. When the rotating ash and slag rotate to the large ash knife 53, the largest surface of the large ash knife 53 contacts the ash and slag, which can intercept some ash and slag, making it accumulate at the ash outlet 41. When the accumulation amount of ash and slag reaches a certain level, it is discharged from the ash outlet 41, avoiding the chaotic accumulation of ash and slag in the slag chute 4, reducing the cleaning difficulty, and providing great convenience for the subsequent collection and treatment of ash and slag. Among them, the small ash knife 41 can be used to handle finer ash and slag, and the large ash knife 53 handles larger ash and slag. And because the ash scraping knives 51, small ash knives 52, large ash knives 53 have different shapes, different heights, and different radial positions, a multi-level slag discharge structure can be formed to enhance the slag discharge capacity. Different shapes may affect the cutting and pushing efficiency, different heights may control the thickness of the slag layer, and different radial positions may cover different areas to ensure comprehensive slag discharge.

[0183] Embodiment 2

[0184] In this embodiment, as Figure 6 and 7 shown, an ash discharge baffle 531 is provided on the large ash knife 53, which is attached to the large ash knife 53 and one end thereof extends beyond the width of the large ash knife 53. The ash and slag are concentrated together, and when it reaches a certain amount, it automatically discharges along the ash outlet 41.

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

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

[0187] Embodiment 3

[0188] As Figure 8 and 9As shown, compared with Embodiment 2, most parts are the same, except that in this embodiment, a conical top cover 321 with its tip facing upward is provided at the top of the conical grate 32, and a plurality of air outlets are provided on the top cover 321, and a spray mask 322 is provided above each air outlet. The air outlets ensure that air can be evenly distributed during the gasification process, promote the full combustion of biomass, and reduce the content of unburned substances in the ash residue. The spray mask 322 adopts a convex structure, significantly increasing the friction surface area of the conical grate 32. When the primary air enters the furnace, the spray mask 322 guides the air flow to fully contact the material, realizing the uniform combustion of the material. At the same time, the spray mask 322 changes the movement trajectory of the air flow in the furnace, indirectly increasing the form of fluid disturbance in the furnace, making the spreading thickness of the material on the grate more uniform, and ensuring that the ash residue can fall smoothly. In this embodiment, a plurality of the air outlets form a plurality of concentric annular arrays with the tip of the top cover 321 as the center, and the arrays are arranged at intervals in the radial direction.

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

[0190] Embodiment 4

[0191] Compared with Embodiment 3, most parts are the same, except that the gasifier further includes a slag separation and collection assembly 6 for separating and collecting the slag discharged from the ash outlet 41, as Figure 10 shown, which includes:

[0192] An ash outlet trough 61 with a sieve 6111;

[0193] A small-volume slag collector 62 for collecting the small-volume slag falling from the sieve 6111;

[0194] And a large-volume slag collector 63 for collecting the large-volume slag discharged from the ash outlet trough 61.

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

[0196] In this embodiment, the bottom surface 611 has a structure with a wider top and a narrower bottom, and the ash outlet trough 61 is inclined, which helps the slag to slide naturally by its own gravity.

[0197] In this embodiment, the ash discharge chute 61 is not connected to the rotary ash pan 2 and 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 chute 61.

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

[0199] In this embodiment, the ash and slag discharged from the ash discharge port 41 enter the ash discharge chute 61. According to the particle size of the ash and slag, the ash and slag with smaller volume are accurately screened out through the screen 6111, and the screened ash and slag fall into the small-volume ash and slag collector 62 below. The large-volume ash and slag that are not filtered by the screen 6111 are discharged from the bottom of the ash discharge chute 61 and reach the large-volume ash and slag collector 63, which is beneficial to the centralized collection of large- and small-volume ash and slag and lays a foundation for subsequent resource recovery and treatment.

[0200] Embodiment 5

[0201] Compared with Embodiment 4, most of them are the same, except that the ash scraping knife 52 is a cylindrical structure, and its circular bottom is connected to the outer side wall of the rotary grate tower 3.

[0202] Embodiment 6

[0203] Compared with Embodiment 4, most of them are the same, except that the tangential angle between the arc edge of the first arc 521 and the first straight line 522 is 20°, the tangential angle between the arc edge of 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] Embodiment 7

[0205] Compared with Embodiment 4, most of them are the same, except that the tangential angle between the arc edge of the first arc 521 and the first straight line 522 of the small ash knife 52 is 30°, the tangential angle between the arc edge of 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 knife 52 to the height of the small ash knife 52 is 1.15.

[0206] Embodiment 8

[0207] Compared with Embodiment 4, most of them are the same, except that the tangential angle between the arc edge of the first arc 521 and the first straight line 522 of the small ash knife 52 is 23.4°, 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 18°. The ratio of the first arc 521 of the small ash knife 52 to the height of the small ash knife 52 is 1.36.

[0208] Example 9

[0209] Compared with Example 4, most of them are the same, except that the inclination angle of the large gray knife 53 is 25°.

[0210] Example 10

[0211] Compared with Example 4, most of them are the same, except that the inclination angle of the large gray knife 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 on the basis of the present invention, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. An ash and slag discharging device for a fixed-bed biomass gasifier, characterized in that, Comprising: A rotary ash pan (2) disposed at the bottom of the furnace body (1) of the gasifier without contacting it; A rotary grate tower (3) disposed within the rotary ash pan (2) and rotating synchronously therewith, with the top of the rotary grate tower (3) extending into the furnace body (1) and the bottom connected to a ventilation system; A slag chute (4) located between the inner wall of the rotary ash pan (2) and the rotary grate tower (3) and used for collecting ash and slag, and an ash discharge port (41) for discharging ash and slag is provided on its side wall; And an ash discharging assembly (5), which includes a plurality of ash scraping blades (51) installed on the outer side wall of the rotary grate tower (3), a plurality of small ash blades (52) installed at the bottom of the furnace body (1), and a large ash blade (53) installed on the outer side wall of the furnace body (1).

2. The ash discharging device of a fixed-bed biomass gasifier according to claim 1, characterized in that, The ash scraping blade (51) includes a conical structure and a cylindrical structure, and its circular bottom is connected to the outer side wall of the rotary grate tower (3); There are two ash scraping blades (51), which are symmetrically distributed on both sides of the rotary grate tower (3).

3. The ash discharging device of a fixed-bed biomass gasifier according to claim 1, characterized in that, The small ash blade (52) is a sheet-like structure, and its thickness decreases in a gradient. Among them, the end of the small ash blade (52) far from the rotary grate tower (3) has the largest thickness, and the end close to the rotary grate tower (3) has the smallest thickness; The cross-sectional shape of the small ash blade (52) at any height is the same, and the cross-section is an arc-edge triangle shape, which is a closed figure composed of a first arc (521), a first straight line (522), and a second straight line (523).

4. The ash discharging device of a fixed-bed biomass gasifier according to claim 1, characterized in that, There are 4 to 8 small ash blades (52), which are circumferentially and equally spaced along the bottom edge of the furnace body (1), and the shapes, sizes, and directions of the small ash blades (52) are the same.

5. The ash discharging device of a fixed-bed biomass gasifier according to claim 1, characterized in that, The large ash blade (53) is a sheet-like structure inclined from top to bottom on the outer side wall of the furnace body (1), and its width decreases in a gradient from top to bottom.

6. The ash discharging device of a fixed-bed biomass gasifier according to claim 1, characterized in that, An ash discharge baffle (531) that fits against the large ash blade (53) and one end extends beyond the width of the large ash blade (53) is provided on the large ash blade (53).

7. The ash discharging device of a fixed-bed biomass gasifier according to claim 1, wherein, The horizontal center lines of the ash scraping blade (51), the small ash blade (52), and the large ash blade (53) are not at the same height.

8. The ash discharging device of a fixed-bed biomass gasifier according to claim 1, characterized in that, The centers of the circumferential projections of the ash scraping blade (51), the small ash blade (52), and the large ash blade (53) along the furnace body (1) are not on the same radial line.

9. The ash discharging device of a fixed-bed biomass gasifier according to claim 1, characterized in that, The ash and slag discharging 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 discharge port (41), which includes: An ash discharge chute (61) with a screen (6111); A small volume ash and slag collector (62) for collecting small volume ash and slag falling from the screen (6111); And a large volume ash and slag collector (63) for collecting large volume ash and slag discharged from the ash discharge chute (61).

10. A method for discharging ash and slag from a fixed-bed biomass gasifier, characterized in that, It is implemented by using the ash and slag discharging device according to any one of claims 1 to 9.

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