Straw bale burning direct-fired semi-gasification biomass boiler

Abstract

The present invention discloses a direct-fired semi-gasification biomass boiler for straw bale burning, comprising: a boiler body, a straw drying and breaking chamber, and a chain grate; the boiler body comprises a boiler shell and a furnace, and the boiler shell is fixed to the top of the furnace; a rear arch, a front arch, a partition wall, etc. are fixed in the furnace and have a semi-gasification combustion chamber, a fixed carbon burnout chamber, and an enhanced combustion chamber; the chain grate is horizontally arranged at the bottom of the furnace and a plurality of air chambers are arranged below it along its conveying direction; the straw drying and breaking chamber is arranged in front of the feed port of the boiler body, and a straw breaking device is arranged inside it. The present invention solves the problem of direct-fired straw bale burning by arranging a straw breaking device; due to the use of a chain grate, continuous feeding and continuous slag discharge are possible; at the same time, the staged combustion of the semi-gasification combustion chamber, the fixed carbon burnout chamber, and the enhanced combustion chamber not only improves the combustion effect, but also produces a low concentration of nitrogen oxides, achieving the effect of energy saving and environmental protection.

Description

Technical Field

[0001] The invention relates to the technical field of straw combustion, and in particular to a straw bundle burning direct-fired semi-gasification biomass boiler. Background Art

[0002] As the consumption of fossil energy leads to the intensification of greenhouse gas effects and the frequent occurrence of haze in my country, people's environmental awareness continues to increase. Therefore, how to curb pollution emissions at the source has become a top priority, and finding a clean and reliable energy source is also imminent. Biomass energy is widely regarded as an environmentally friendly renewable energy source with "zero CO2 emissions". Therefore, the application of biomass energy has received worldwide attention.

[0003] Straw is one of the most important biomass fuels. When straw fuel is burned directly, it is inconvenient to transport and labor-intensive due to its small size and low density. Therefore, the application of direct burning of straw fuel is limited. Another method is to collect straw fuel into round or square packages, transport it back to the processing plant for briquetting or pressing it into particles before burning. Although this straw molding fuel has a high fuel density and high energy per unit volume after processing, its combustion temperature is higher than the ash melting point, which can easily cause coking. It also consumes a lot of electricity resources, has low production efficiency, and has high molding equipment costs and maintenance costs. There is also a straw bale burning technology, which has the characteristics of moderate straw bale density and low energy consumption. Compared with straw molding fuel, this fuel cost can be reduced by more than half, and at the same time, the productivity is high. If the bales of straw are dried before burning, the moisture content is reduced to less than 20%, and then the bales of straw are sent to the furnace for burning, this method is the most economical.

[0004] However, the existing straw bale burning boiler cannot ensure the full combustion of the straw bale. The straw bale is burned naturally in the boiler by the blower, which not only has a slow combustion speed, but also incomplete combustion of the straw and low thermal efficiency.

[0005] Therefore, how to solve the technical shortcomings of existing straw bale burning boilers and provide a straw bale burning direct-fired semi-gasification biomass boiler that can fully burn straw bales in the boiler, has high thermal efficiency, and is energy-saving and environmentally friendly is a problem that technical personnel in this field urgently need to solve. Summary of the invention

[0006] To this end, the purpose of the present invention is to propose a straw bale burning direct-fired semi-gasification biomass boiler to effectively solve the above-mentioned problems existing in the existing straw bale burning technology. The specific technical solution is as follows:

[0007] A straw bale burning direct-fired semi-gasification biomass boiler, comprising: a boiler body, a straw drying and breaking chamber, and a chain grate;

[0008] The boiler body comprises a boiler shell and a furnace, wherein the boiler shell is fixed to the top of the furnace; a rear arch is fixed to the rear end of the furnace, a front arch is fixed to the front end, and a partition wall is fixed in the furnace and is located between the rear arch and the front arch; the partition wall, the front arch and the furnace together form a semi-gasification combustion chamber; the rear arch top wall, the partition wall and the furnace together form an enhanced combustion chamber; the rear arch lower wall, the partition wall and the furnace together form a fixed carbon burnout chamber; a flame jet connecting the semi-gasification combustion chamber and the enhanced combustion chamber is provided on the partition wall, and a smoke outlet connecting the enhanced combustion chamber and the fixed carbon burnout chamber is provided on the end of the rear arch close to the partition wall; a smoke outlet is provided on the top of the enhanced combustion chamber, and the smoke outlet is connected to a flue for discharging post-combustion smoke;

[0009] The chain grate is horizontally arranged at the bottom of the furnace and there is a gap between its top surface and the bottom end of the isolation wall, and a plurality of air chambers are arranged below the chain grate along its conveying direction;

[0010] The straw drying and bale breaking chamber is arranged in front of the feed port of the boiler body, and a straw bale breaking device is arranged inside the chamber. The feed port is used to transport straw fuel to the chain grate; the straw bale breaking device includes a bale breaking roller assembly, which is fixed to the left and right side walls of the straw drying and bale breaking chamber through a bearing seat and is used for breaking straw bales; one end of the bale breaking roller assembly is connected to a water cooling circulation system to achieve temperature reduction protection for its own structure.

[0011] By adopting the above technical scheme, the present invention first solves the problem of direct combustion of straw bales: the baled straw does not need to be processed into particles or briquettes, thus eliminating the intermediate processing link and reducing the operating cost; two to three straw bales can be placed in the straw drying and breaking chamber of the present invention, and when the first straw bale is broken, the second and third straw bales are simultaneously dried by the radiation of flue gas in the chamber, thereby reducing the moisture in the straw and facilitating the combustion of the straw bales in the furnace after the straw bales are broken; at the same time, since the density of the straw becomes smaller after the straw bales are broken, the combustion temperature does not reach the ash melting point of the straw ash, so it is not easy to coke during combustion.

[0012] Secondly, the present invention adopts a chain grate, which can continuously feed and discharge slag; at the same time, the staged combustion of the semi-gasification combustion chamber, the fixed carbon burnout chamber and the enhanced combustion chamber not only improves the combustion effect, but also produces a low concentration of nitrogen oxides, achieving the effect of energy saving and environmental protection.

[0013] On the basis of the above technical solution, the present invention can also make the following improvements:

[0014] Preferably, in the above-mentioned straw bale burning direct-fired semi-gasification biomass boiler, the boiler body also includes a front smoke box, a rear smoke box, a threaded smoke pipe, a header, a downcomer, and a convection tube bundle. The front smoke box is fixed to the front end cover of the boiler shell and is connected to the end of the flue away from the smoke outlet; the rear smoke box is fixed to the rear end cover of the boiler shell for discharging flue gas; the threaded smoke pipe is fixed inside the boiler shell and its two ends are respectively connected to the front smoke box and the rear smoke box; the flue is an eight-shaped flue and is located on both sides of the top of the semi-gasification combustion chamber and the enhanced combustion chamber; the header is located on both sides of the upper part of the chain grate and a return water port is provided at its rear end, and the upper side of the header is connected to the boiler shell through the downcomer and the convection tube bundle; a water outlet connected to the return water port is provided on the boiler shell.

[0015] The boiler of the present invention adopts the threaded smoke tube technology, which increases the heating area of ​​the boiler shell and improves the utilization rate of combustion heat. At the same time, sufficient heating surfaces (headers, downcomers and convection tube bundles) are arranged to fully absorb heat, the boiler exhaust temperature is low, and the thermal efficiency is high.

[0016] Preferably, in the above-mentioned straw bale burning direct-fired semi-gasification biomass boiler, the downcomer is located at the rear end of the furnace, and the top of the convection tube is arranged around the figure-eight flue.

[0017] The boiler of the present invention reasonably arranges the heating surfaces of the boiler shell, header, downcomer, convection tube bundle and threaded smoke tube, etc., on the one hand, reduces the exhaust gas temperature by staged heat exchange, and on the other hand, adopts high-efficiency heat transfer elements to greatly improve the boiler efficiency.

[0018] Preferably, in the above-mentioned straw bale burning direct-fired semi-gasification biomass boiler, there is a gap of 1000-1300 mm between the top surface of the chain grate and the bottom end of the isolation wall to ensure that the broken straw bales can enter the furnace.

[0019] Preferably, in the above-mentioned straw bale burning direct-fired semi-gasification biomass boiler, the bale breaking roller assembly includes two bale breaking shafts, the outer surfaces of the bale breaking shafts are provided with bale breaking thorns or iron plates for breaking bales, and the interiors are provided with channels for circulating cooling circulating water; the shaft ends of the bale breaking shafts are provided with outlet and return water pipe heads; the water-cooling circulation system includes a circulating pump and a water pipe connected to the water inlet of the circulating pump, and the circulating pump is connected to the outlet and return water pipe heads through a hose.

[0020] The bale breaking shaft can quickly break the straw bales, and the scattered straw can also be preliminarily burned in the straw drying and breaking chamber to improve its subsequent combustion effect; at the same time, the water cooling circulation system can ensure that the bale breaking roller assembly, bearing seat and other structures will not be in a high temperature state for a long time, ensuring the working ability of these structures and extending their service life.

[0021] Preferably, in the above-mentioned straw bale burning direct-fired semi-gasification biomass boiler, the broken package shaft is equipped with a double-sided water seal and a sealing rubber ring for sealing cooling water.

[0022] Preferably, in the above-mentioned straw bale burning direct-fired semi-gasification biomass boiler, the bale breaking is achieved by the rotation of the bale breaking shaft driven by a transmission motor to drive a chain and a sprocket.

[0023] Preferably, in the above-mentioned straw bale burning direct-fired semi-gasification biomass boiler, the wind chamber is an isobaric wind chamber and is evenly distributed below the chain grate to evenly transport the oxygen required for straw combustion into the furnace.

[0024] Preferably, in the above-mentioned straw bale burning direct-fired semi-gasification biomass boiler, a recovery and processing device for recovering and processing straw combustion waste residue is provided at the rear end of the chain grate.

[0025] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a straw bale burning direct-fired semi-gasification biomass boiler, which has the following beneficial effects:

[0026] 1. The straw does not need to be processed into pellets or briquettes and can be burned directly, eliminating the intermediate processing steps and thus greatly reducing operating costs.

[0027] 2. After the straw bale is broken, the density of the straw is small, and the combustion temperature does not reach the ash melting point of the straw ash, so it is not easy to coke during combustion.

[0028] 3. As it adopts chain grate, it can continuously feed and discharge slag.

[0029] 4. The staged combustion of the semi-gasification combustion chamber, fixed carbon burnout chamber and enhanced combustion chamber not only improves the combustion effect, but also produces low concentration of nitrogen oxides, achieving the effect of energy saving and environmental protection.

[0030] 5. The boiler adopts threaded spiral tube technology and arranges enough heating surfaces, so the heat is fully absorbed, the boiler exhaust temperature is low and the thermal efficiency is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0032] Figure 1 The accompanying drawing is a schematic diagram of the main cross-section structure provided by the present invention.

[0033] Figure 2 The attached picture is Figure 1 Schematic diagram of the left cross-section structure.

[0034] Among them, in the figure,

[0035] 1- boiler body, 2- boiler shell, 3- furnace, 4- rear arch, 5- front arch, 6- separation wall, 7- semi-gasification combustion chamber, 8- enhanced combustion chamber, 9- fixed carbon burnout chamber, 10- flame nozzle, 11- flue gas outlet, 12- flue, 13- chain grate, 14- isobaric air chamber, 15- bale breaking roller assembly, 16- bale breaking shaft, 17- water cooling circulation system, 18- straw drying and bale breaking chamber, 19- front smoke box, 20- rear smoke box, 21- threaded smoke pipe, 22- header, 23- downcomer, 24- convection tube bundle. DETAILED DESCRIPTION

[0036] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0037] In the description of the present invention, it is necessary to understand that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are 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 cannot be understood as a limitation on the present invention.

[0038] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0039] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it 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 the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0041] Example:

[0042] According to the following Figure 1-2 A straw bale burning direct-fired semi-gasification biomass boiler according to an embodiment of the present invention is described in detail.

[0043] See attached Figure 1 and attached Figure 2 The embodiment of the present invention discloses a straw bale burning direct-fired semi-gasification biomass boiler, comprising: a boiler body 1, a straw drying and breaking chamber 18, and a chain grate 13, wherein the chain grate 13 is horizontally arranged at the bottom of the furnace 3 of the boiler body 1, and the straw drying and breaking chamber 18 is arranged in front of the feed inlet of the boiler body 1.

[0044] The boiler body 1 includes a boiler shell 2 and a furnace 3 , and the boiler shell 2 is fixed on the top of the furnace 3 .

[0045] A rear arch 4 is fixed to the rear end of the furnace 3 , a front arch 5 is fixed to the front end, and a partition wall 6 is fixed in the furnace 3 and located between the rear arch 4 and the front arch 5 .

[0046] Furthermore, the upper part of the front arch 5 is composed of an inclined wall extending obliquely upward from front to rear, and the lower part of the front arch 5 is composed of a vertical wall extending vertically. The rear arch 4 is composed of a transverse wall extending horizontally from rear to front in front of the rear furnace wall and an inclined wall extending obliquely upward. The front part of the rear arch 4 is located on the upper side of the rear end of the chain grate 13. Such a large space design is more conducive to the full combustion of straw fuel.

[0047] The partition wall 6, the front arch 5 and the furnace 3 together form a semi-gasification combustion chamber 7; the top wall of the rear arch 4, the partition wall 6 and the furnace 3 together form an enhanced combustion chamber 8; the lower wall of the rear arch 4, the partition wall 6 and the furnace 3 together form a fixed carbon burnout chamber 9.

[0048] A flame outlet 10 connecting the semi-gasification combustion chamber 7 and the enhanced combustion chamber 8 is provided on the isolation wall 6 , and a smoke outlet 11 connecting the enhanced combustion chamber 8 and the fixed carbon burnout chamber 9 is provided at the end of the rear arch 4 close to the isolation wall 6 .

[0049] The top of the enhanced combustion chamber 8 is provided with a smoke outlet, which is connected to a flue 12 for discharging smoke after combustion.

[0050] Furthermore, the boiler body 1 also includes a front smoke box 19 , a rear smoke box 20 , a threaded smoke pipe 21 , a header 22 , a downcomer 23 , and a convection tube bundle 24 .

[0051] The front smoke box 19 is fixed on the front end cover of the boiler shell 2 and is connected to the end of the flue 12 away from the smoke outlet; the rear smoke box 20 is fixed on the rear end cover of the boiler shell 2 for discharging smoke; the threaded smoke pipe 21 is fixed inside the boiler shell 2 and its two ends are respectively connected to the front smoke box 19 and the rear smoke box 20.

[0052] The flue 12 is an eight-shaped flue and is located on both sides of the top of the semi-gasification combustion chamber 7 and the enhanced combustion chamber 8. The header 22 is located on both sides of the upper part of the chain grate 13 and a water return port is provided at its rear end. The upper side of the header 22 is connected to the boiler shell 2 through a downcomer 23 and a convection tube bundle 24, that is, the two ends of the downcomer 23 are respectively connected to the boiler shell 2 and the header 22, and the two ends of the convection tube bundle 24 are respectively connected to the boiler shell 2 and the header 22; the downcomer 23 is located at the rear end of the furnace 3, and the top of the convection tube bundle 24 is arranged around the eight-shaped flue 12. The boiler shell 2 is provided with a water outlet connected to the water return port.

[0053] The chain grate 13 is horizontally arranged at the bottom of the furnace 3, with a gap of 1000-1300 mm, preferably 1100 mm, between its top surface and the bottom end of the isolation wall 6; a plurality of isobaric air chambers 14 are evenly distributed below the chain grate 13 along its conveying direction.

[0054] Furthermore, a recycling device for recycling straw combustion waste residue is provided at the rear end of the chain grate 13 .

[0055] The straw drying and bag breaking chamber 18 is arranged in front of the feed inlet of the boiler body 1 , and a straw bag breaking device is arranged inside the chamber. The feed inlet is used to transport the straw fuel to the chain grate 13 .

[0056] Specifically, the straw bale breaking device includes a bale breaking roller assembly 15, which is fixed to the left and right side walls of the straw drying and bale breaking chamber 18 through a bearing seat and is used to break straw bales. At the same time, the flame of the straw drying and bale breaking chamber can also initially burn off the scattered straw; one end of the bale breaking roller assembly 15 is connected to the water cooling circulation system 17 to achieve cooling protection of its own structure.

[0057] More specifically, the bale breaking roller assembly 15 includes two bale breaking shafts 16, which are fixed to the left and right side walls of the straw drying bale breaking chamber 18 through bearing seats, and bale breaking thorns or iron plates for breaking bales are provided on the outer surfaces of the bale breaking shafts 16.

[0058] A channel for circulating cooling water is provided inside the bale breaking shaft 16; outlet and return water pipe heads are provided on the shaft end of the bale breaking shaft 16, and the water cooling circulation system 17 includes a circulation pump and a water pipe connected to the water inlet of the circulation pump. The circulation pump is connected to the outlet and return water pipe heads through a hose. The continuous circulation of cooling water in the bale breaking shaft 16 can achieve timely cooling of the corresponding structures on the straw bale breaking device, thereby ensuring the working capacity of these structures and extending their service life.

[0059] In order to further optimize the above technical solution, a double-sided water seal and a sealing rubber ring for sealing cooling water are also installed in the bag breaking shaft 16.

[0060] In order to further optimize the above technical solution, the bag breaking shaft 16 is rotated to break the bag by driving the chain and sprocket by the transmission motor.

[0061] The specific working principle of the present invention is:

[0062] Several straw bales are fed into the straw drying and breaking chamber 18 in front of the boiler feed port. The two breaking shafts 16 drive the breaking thorns or iron plates thereon to break the straw bales. During the breaking of one straw bale, the other straw bales in the chamber are radiated by the flue gas and dried at the same time. At the same time, the circulation pump is started to continuously cool down the two breaking shafts 16 and other corresponding structures.

[0063] The broken and burned straw falls onto the chain grate 13 through the feed port, and the isobaric wind chamber 14 at the lower part of the chain grate 13 supplies an appropriate amount of air. A large amount of volatile components are precipitated from the straw after combustion and fill the semi-gasification combustion chamber 7. Since the density of the straw bale decreases after the straw bale is broken, its combustion temperature does not reach the ash melting point of the straw ash, and it is not easy to coke during combustion. At the same time, the temperature of the semi-gasification combustion chamber 7 is controlled below 800°C, which is lower than the ash melting point, and can also effectively prevent coking and inhibit the formation of nitrogen oxides. The generated gas enters the enhanced combustion chamber 8 through the flame nozzle 10.

[0064] In the above process, the straw that is not completely burned in the semi-gasification combustion chamber 7 is spread flat on the chain grate 13 in the space below the isolation wall 6. With the uniform movement of the chain grate 13 and the uniform wind distribution of the isobaric wind chamber 14, the solid carbon formed is fully burned in the combustion zone under the action of the radiant heat of the rear arch 4, and the formed high-temperature flue gas flows through the flue gas outlet 11 into the enhanced combustion chamber 8 and merges with the flue gas ejected from the semi-gasification combustion chamber 7 for secondary combustion. This process realizes phase-separated combined combustion, the concentration of nitrogen oxides generated is low, and the atmospheric environmental protection effect is good.

[0065] The flue gas enters the eight-shaped flue 12 from the top of the enhanced combustion chamber 8, and then gathers in the front smoke box 19, flows through the heating surface of the threaded smoke pipe 21, and finally is discharged to the atmosphere from the rear smoke box 20.

[0066] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0067] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A straw bale burning direct-fired semi-gasification biomass boiler, characterized in that: include: Boiler body (1), straw drying and bag breaking chamber (18), chain grate (13); The boiler body (1) comprises a boiler shell (2) and a furnace (3), wherein the boiler shell (2) is fixed to the top of the furnace (3); a rear arch (4) is fixed to the rear end of the furnace (3), and a front arch (5) is fixed to the front end; a partition wall (6) is fixed in the furnace (3) and is located between the rear arch (4) and the front arch (5); the partition wall (6), the front arch (5) and the furnace (3) together form a semi-gasification combustion chamber (7); the top wall of the rear arch (4), the partition wall (6) and the furnace (3) together form an enhanced combustion chamber (8) The lower wall of the rear arch (4), the partition wall (6) and the furnace (3) together enclose a fixed carbon burnout chamber (9); the partition wall (6) is provided with a flame vent (10) communicating with the semi-gasification combustion chamber (7) and the enhanced combustion chamber (8); the end of the rear arch (4) close to the partition wall (6) is provided with a smoke outlet (11) communicating with the enhanced combustion chamber (8) and the fixed carbon burnout chamber (9); the top of the enhanced combustion chamber (8) is provided with a smoke outlet, and the smoke outlet is connected to a smoke duct (12) for discharging post-combustion smoke; The chain grate (13) is horizontally arranged at the bottom of the furnace (3) and there is a gap between its top surface and the bottom end of the isolation wall (6), and a plurality of wind chambers are arranged below the chain grate (13) along its conveying direction; The straw drying and bale breaking chamber (18) is arranged in front of the feed port of the boiler body (1), and a straw bale breaking device is arranged inside the chamber, and the feed port is used to transport straw fuel to the chain grate (13); the straw bale breaking device comprises a bale breaking roller assembly (15), and the bale breaking roller assembly (15) is fixed to the left and right side walls of the straw drying and bale breaking chamber (18) through a bearing seat, and is used to break straw bales; one end of the bale breaking roller assembly (15) is connected to a water cooling circulation system (17) to achieve temperature reduction protection for its own structure; the bale breaking roller assembly (15) comprises two bale breaking shafts (16), and bale breaking thorns or iron plates for breaking bales are arranged on the outer surface of the bale breaking shafts (16), and channels for circulating cooling circulating water are arranged inside the bale breaking shafts (16); A plurality of straw bales are fed into a straw drying and breaking chamber (18) in front of a boiler feed port, and two breaking shafts (16) are rotated to drive breaking spikes or iron plates thereon to break the straw bales. During the process of breaking one straw bale, the other straw bales in the chamber are radiated by the flue gas and dried at the same time. The broken and burned straw falls onto the chain grate (13) through the feed port; The wind chamber is an isobaric wind chamber (14) and is evenly distributed below the chain grate (13).

2. The straw bale burning direct-fired semi-gasification biomass boiler according to claim 1, characterized in that: The boiler body (1) further comprises a front smoke box (19), a rear smoke box (20), a threaded smoke pipe (21), a header (22), a downcomer (23), and a convection tube bundle (24); the front smoke box (19) is fixed to the front end cover of the boiler shell (2) and is connected to an end of the flue (12) away from the smoke outlet; the rear smoke box (20) is fixed to the rear end cover of the boiler shell (2) and is used to discharge smoke; the threaded smoke pipe (21) is fixed inside the boiler shell (2) and has two ends respectively connected to the front end cover of the boiler shell (2). The front smoke box (19) and the rear smoke box (20) are connected; the flue (12) is an eight-shaped flue and is located on both sides of the top of the semi-gasification combustion chamber (7) and the enhanced combustion chamber (8); the header (22) is located on both sides of the upper part of the chain grate (13) and a water return port is provided at its rear end; the upper side of the header (22) is connected to the boiler shell (2) through the downcomer (23) and the convection tube bundle (24); and a water outlet connected to the water return port is provided on the boiler shell (2).

3. The straw bale burning direct-fired semi-gasification biomass boiler according to claim 2, characterized in that: The downcomer (23) is located at the rear end of the furnace (3), and the top of the convection tube is arranged around the figure-eight flue (12).

4. The straw bale burning direct-fired semi-gasification biomass boiler according to claim 1, characterized in that: There is a gap of 1000-1300 mm between the top surface of the chain grate (13) and the bottom end of the isolation wall (6).

5. The straw bale burning direct-fired semi-gasification biomass boiler according to claim 1, characterized in that: The end of the bag breaking shaft (16) is provided with a water outlet and a water return pipe head; the water cooling circulation system (17) comprises a circulation pump and a water pipe connected to the water inlet of the circulation pump, and the circulation pump is connected to the water outlet and the water return pipe head through a hose.

6. The straw bale burning direct-fired semi-gasification biomass boiler according to claim 5, characterized in that: The bag breaking shaft (16) is provided with a double-sided water seal and a sealing rubber ring for sealing cooling water.

7. The straw bale burning direct-fired semi-gasification biomass boiler according to claim 5, characterized in that: The bale breaking shaft (16) is rotated to break the bale by driving a chain and a sprocket with a transmission motor.

8. The straw bale burning direct-fired semi-gasification biomass boiler according to claim 1, characterized in that: A recycling device for recycling straw combustion waste residue is provided at the rear end of the chain grate (13).

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