Indirect coupling combustion accompanying type bundled straw biomass direct-fired boiler

Abstract

The utility model discloses an indirect coupling combustion accompanying type straw bundling biomass direct-fired boiler, relates to the technical field of biomass direct-fired boilers, and solves the problems that straw cannot be normally combusted due to too high moisture and soil content after being collected and packaged under natural conditions, or the combustion is insufficient, and the heat conversion efficiency is low. Comprising a boiler body, an in-boiler transmission system, a first chain grate and a second chain grate, and the in-boiler transmission system is used for transferring biomass fuel filled from a feeding port to the first chain grate to achieve sufficient combustion of the biomass fuel; the adding hopper is used for adding biomass fuel to the second chain grate stoker; the first chain grate stoker and the second chain grate stoker are both used for transferring biomass fuel which is located above the first chain grate stoker and the second chain grate stoker and is fully combusted to the slag falling opening. The biomass direct-fired boiler structure for combustion work doing through up-down positive and negative multiple strokes in the boiler is adopted for heat supply production, the raw material obtaining range can be widened, the raw material purchasing cost is saved, the raw material consumption is reduced, and the fault rate of production equipment is reduced.

Description

Technical Field

[0001] This utility model relates to the technical field of biomass direct-fired boilers, and in particular to an indirect coupling co-firing type baled straw biomass direct-fired boiler. Background Technology

[0002] Northeast my country boasts abundant straw reserves, convenient collection and baling conditions, and low-cost direct use as fuel. Furthermore, the pollutant emissions from straw combustion are significantly lower than those from coal combustion; with appropriate dust removal and denitrification processes, emissions can meet standards. Biomass baled straw direct combustion is an excellent alternative to coal for applications such as residential heating, industrial gasification, and grain drying. The biomass direct combustion boiler structure, featuring a two-stage coupled combustion process within the biomass straw baling furnace, was developed to address the problem of incomplete combustion and low heat conversion efficiency caused by the high moisture and soil content of straw collected and baled under natural conditions.

[0003] When the moisture content of baled straw exceeds 30% and the soil content is greater than 15%, it will result in incomplete combustion or no combustion when it is used in a biomass straw direct combustion boiler modified from a traditional horizontal coal-fired boiler. At this time, the boiler can no longer be used normally.

[0004] Due to climate uncertainty, the amount of straw collected and stored that meets combustion standards is highly uncertain. Compared to secondary processing of collected straw, providing a direct-fired biomass baled straw stove suitable for straw with a moisture content of around 60% and a soil content of around 30% is significantly more economical and environmentally friendly, offering a more sustainable path for comprehensive straw management and environmental protection. Utility Model Content

[0005] In view of the above-mentioned problems that straw cannot burn properly or has low heat conversion efficiency due to excessive moisture and soil content after being collected and baled under natural conditions, the purpose of this utility model is to provide an indirect coupling co-firing type direct combustion boiler for baled straw biomass.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] An indirect coupling co-firing type baled straw biomass direct combustion boiler includes: a boiler body 1, the boiler body 1 having a combustion chamber 11 and a heat exchange chamber 12 inside, the heat exchange chamber 12 being located above the combustion chamber 11 and connected to the combustion chamber 11;

[0008] The side wall of the combustion chamber 11 is provided with a feed inlet 104 and a feeding hopper 114; the side wall of the heat exchange chamber 12 is provided with a flue gas outlet 105.

[0009] It also includes: an in-furnace drive system 3, a first chain grate 4, and a second chain grate 113. The first chain grate 4 and the second chain grate 113 are both installed at the bottom of the combustion chamber 11. The in-furnace drive system 3 is installed inside the combustion chamber 11 and located above the first chain grate 4. The in-furnace drive system 3 is used to transfer the biomass fuel filled by the feed port 104 to the first chain grate 4 to achieve complete combustion of the biomass fuel. The feed hopper 114 is used to add biomass fuel to the second chain grate 113. The bottom of the combustion chamber 11 is provided with a slag discharge port, which is located between the first chain grate 4 and the second chain grate 113. The first chain grate 4 and the second chain grate 113 are both used to transfer the biomass fuel located above them and which has been fully burned to the slag discharge port.

[0010] In the aforementioned indirect coupling co-firing type baled straw biomass direct combustion boiler, the feed inlet 104 and the feeding hopper 114 are both located on the front side wall of the combustion chamber 11, and the feeding hopper 114 is located below the feed inlet 104. The first chain grate 4 is arranged near the rear side wall of the combustion chamber 11, and the second chain grate 113 is arranged near the front side wall of the combustion chamber 11.

[0011] The aforementioned indirect coupling co-firing baled straw biomass direct combustion boiler includes an in-furnace transmission system 3 comprising: at least one row of material conveying mechanisms, with multiple rows of material conveying mechanisms arranged sequentially from top to bottom; the front end of the uppermost material conveying mechanism is located near the front side wall of the combustion chamber 11 and below the feed inlet 104; the front end of the lowermost material conveying mechanism is located near the front side wall of the combustion chamber 11; for any row of material conveying mechanisms, when its front or rear end is located near the side wall of the combustion chamber 11, its other end is spaced from the side wall of the combustion chamber 11, and the distance between the other end and the side wall of the combustion chamber 11 is greater than the maximum size of the biomass fuel.

[0012] In the aforementioned indirect coupling co-firing baled straw biomass direct combustion boiler, if the front end of one row of material conveying mechanisms is located close to the front side wall of the combustion chamber 11, then the rear end of the other row of material conveying mechanisms is located close to the rear side wall of the combustion chamber 11.

[0013] The aforementioned indirect coupling co-firing baled straw biomass direct-fired boiler includes a material conveying mechanism comprising: multiple drive shafts located in the same plane and arranged parallel to each other; each drive shaft having its two ends rotatably connected to the left and right side walls of the combustion chamber 11; the multiple drive shafts rotating synchronously in a clockwise or counterclockwise direction; and the rotation direction of the multiple drive shafts being the same as the conveying direction of the biomass fuel located above them.

[0014] The aforementioned indirect coupling co-firing type baled straw biomass direct combustion boiler further includes: a baling shaft 5 and a coke-breaking shaft 106. The two ends of the baling shaft 5 are rotatably connected to the left and right side walls of the combustion chamber 11, respectively. The two ends of the coke-breaking shaft 106 are rotatably connected to the left and right side walls of the combustion chamber 11, respectively. Both the baling shaft 5 and the coke-breaking shaft 106 are located above the first chain grate 4. The baling shaft 5 and the coke-breaking shaft 106 rotate synchronously in a clockwise or counterclockwise direction. The rotation direction of the baling shaft 5 and the coke-breaking shaft 106 is the same as the conveying direction of the first chain grate 4.

[0015] The aforementioned indirect coupling co-firing type baled straw biomass direct combustion boiler further includes: a baled straw feeder 2, which is used to transfer biomass fuel to the feed inlet 104 of the boiler body 1 and push it into the combustion chamber 11; the baled straw feeder 2 includes: a structural frame 21, baffles 22 and a hopper 23, the rear end of the structural frame 21 is connected to the feed inlet 104 of the boiler body 1, baffles 22 are installed on the left and right sides of the structural frame 21, and the hopper 23 travels on the upper surface of the structural frame 21, and the hopper 23 is used to push the biomass fuel located on the structural frame 21 into the combustion chamber 11;

[0016] The bottom of the hopper 23 is equipped with wheels, and gears are rotatably mounted on the side of the hopper 23. A rack is provided on the upper surface of the structural frame 21. The gears mesh with the racks, and the hopper 23 moves on the structural frame 21 by driving the gears to rotate.

[0017] The aforementioned indirect coupling co-firing type baled straw biomass direct combustion boiler further includes: water-cooled wall tubes 109, a boiler drum 108 at the top of the heat exchange chamber 12, a burnout chamber 110 at the front of the heat exchange chamber 12, multiple water-cooled wall tubes 109 evenly distributed on the left and right side walls of the boiler drum 108, the burnout chamber 110 and the combustion chamber 11, a water inlet 111 communicating with the water-cooled wall tubes 109 on the rear side wall of the combustion chamber 11, and a drain outlet and / or exhaust outlet communicating with the water-cooled wall tubes 109 on the heat exchange chamber 12.

[0018] The aforementioned indirect coupling co-firing type baled straw biomass direct combustion boiler further includes: a speed reducer unit 6, which is used to drive the furnace transmission system 3, the first chain grate 4, the second chain grate 113, the baling shaft 5, and the coke breaking shaft 106.

[0019] The aforementioned indirect coupling co-firing type baled straw biomass direct combustion boiler has an inclined preheating arch 101 at the top front side of the combustion chamber 11, an inclined limiting arch 102 at the top rear side of the combustion chamber 11, and an inclined burnout arch 107 at the bottom of the combustion chamber 11. The preheating arch 101 is located above the feed inlet 104; the burnout arch 107 is located above the ash discharge port; and air ducts 112 are provided on the left and right side walls of the combustion chamber 11.

[0020] Because this utility model employs the aforementioned technology, it has the following positive effects compared to existing technologies:

[0021] (1) In this utility model, the pot body is designed as a multi-pass smoke passage structure. The superheated flue gas exchanges heat with the water-cooled wall, smoke pipe, smoke box, pot drum, header and connecting pipe bundle through the pot body structure. A cast wall is added to the lower side of the pot drum to realize the two-pass smoke passage of the superheated flue gas, increase the heat exchange area between the flue gas and the pot body, and thus reduce the exhaust temperature.

[0022] (2) In this utility model, the biomass direct-fired boiler structure, which uses multiple forward and reverse strokes inside the furnace for combustion and power generation, can broaden the range of raw material acquisition, save raw material procurement costs, and reduce raw material consumption. At the same time, it can eliminate production safety hazards and reduce the failure rate of production equipment. It fundamentally achieves the economic goal of reducing costs and increasing efficiency in heating production, and protects the property safety of heating equipment and the life safety of boiler operators.

[0023] (3) In this utility model, two sets of grates are designed to be combined into a grate assembly with their tails facing each other to work together. The grate assembly is placed below the boiler body, where the second chain grate is used to burn biomass briquettes and the first chain grate is used to burn straw baled fuel. During operation, since the second chain grate does not have water-cooled walls and connecting tube bundles installed in its chamber structure, the superheated flue gas generated by fuel combustion does not exchange heat in its combustion chamber, but instead enters the corresponding upper combustion chamber directly through the upper fire port at the front end of the furnace arch. This solves the hidden danger caused by insufficient heat replenishment in the boiler combustion chamber when the straw with excessive moisture absorbs too much heat during combustion. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of an indirect coupling co-firing type direct-fired boiler for baled straw biomass.

[0025] Figure 2 This is a cross-sectional view of an indirect coupling co-firing type direct-fired boiler for baled straw biomass according to this utility model.

[0026] Figure 3This is a side view of the boiler body of an indirect coupling co-firing type baled straw biomass direct combustion boiler according to this utility model.

[0027] Figure 4 This is an axonometric view of the main body of an indirect coupling co-firing type baled straw biomass direct combustion boiler according to this utility model.

[0028] In the attached diagram: 1. Boiler body; 2. Straw baling feeder; 3. Furnace transmission system; 4. First chain grate; 5. Bagged baling shaft; 6. Reducer unit; 11. Combustion chamber; 12. Heat exchange chamber; 21. Structural frame; 22. Baffle; 23. Hopper; 101. Preheating furnace arch; 102. Limiting furnace arch; 104. Feed inlet; 105. Smoke outlet; 106. Coke crushing shaft; 107. Burnout furnace arch; 108. Boiler drum; 109. Water-cooled wall tubes; 110. Burnout chamber; 111. Water inlet; 112. Air duct; 113. Second chain grate; 114. Feed hopper. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention.

[0030] Please refer to Figures 1 to 4 As shown, an indirect-coupled co-firing type baled straw biomass direct-fired boiler is illustrated, comprising: a boiler body 1, inside which are a combustion chamber 11 and a heat exchange chamber 12, the heat exchange chamber 12 being located above the combustion chamber 11 and connected to the combustion chamber 11; the combustion chamber 11 is used for burning biomass fuel; the heat exchange chamber 12 is used for heat exchange and external energy supply;

[0031] The side wall of the combustion chamber 11 is provided with a feed inlet 104 and a feeding hopper 114; the side wall of the heat exchange chamber 12 is provided with a flue gas outlet 105.

[0032] It also includes: an in-furnace drive system 3, a first chain grate 4 and a second chain grate 113, both of which are installed at the bottom of the combustion chamber 11. The in-furnace drive system 3 is installed inside the combustion chamber 11 and above the first chain grate 4. The in-furnace drive system 3 is used to transfer the biomass fuel filled through the feed inlet 104 to the first chain grate 4 to achieve complete combustion of the biomass fuel. The feed hopper 114 is used to add biomass fuel to the second chain grate 113. The bottom of the combustion chamber 11 is provided with a slag discharge port, which is located between the first chain grate 4 and the second chain grate 113. Both the first chain grate 4 and the second chain grate 113 are used to transfer the biomass fuel that is located above them and has been fully burned to the slag discharge port.

[0033] Furthermore, in a preferred embodiment, the feed inlet 104 and the feeding hopper 114 are both located on the front side wall of the combustion chamber 11 and the feeding hopper 114 is located below the feed inlet 104. The first chain grate 4 is arranged near the rear side wall of the combustion chamber 11, and the second chain grate 113 is arranged near the front side wall of the combustion chamber 11.

[0034] Furthermore, in a preferred embodiment, the in-furnace transmission system 3 includes: at least one row of material conveying mechanisms, with multiple rows of material conveying mechanisms arranged sequentially from top to bottom; the front end of the uppermost material conveying mechanism is located near the front side wall of the combustion chamber 11 and below the feed inlet 104; the in-furnace transmission system 3 is used to repeatedly move biomass fuel back and forth until the biomass fuel falls from the lowermost material conveying mechanism onto the first chain grate 4; the front end of the lowermost material conveying mechanism is located near the front side wall of the combustion chamber 11; for any row of material conveying mechanisms, when its front or rear end is located near the side wall of the combustion chamber 11, its other end is spaced from the side wall of the combustion chamber 11. The spacing is larger than the maximum size of the biomass fuel, which facilitates the material conveying mechanism to move the biomass fuel from front to back or from back to front to the end. After the biomass fuel falls onto the next material conveying mechanism located on the lower layer, the biomass fuel enters through the feed port 104 and falls to the front end of the material conveying mechanism located on the uppermost layer. The uppermost material conveying mechanism moves the biomass fuel backward until it falls to the rear end of the second layer material conveying mechanism. Then the second layer material conveying mechanism moves it forward until it falls to the front end of the third layer material conveying mechanism... until the biomass fuel falls onto the first chain grate 4. Then the first chain grate 4 moves the fully burned biomass fuel to the ash discharge port.

[0035] Furthermore, in a preferred embodiment, for any two adjacent rows of material conveying mechanisms, if the front end of one row of material conveying mechanisms is located close to the front side wall of the combustion chamber 11, then the rear end of the other row of material conveying mechanisms is located close to the rear side wall of the combustion chamber 11.

[0036] Furthermore, in a preferred embodiment, the end of any material conveying mechanism near the side wall of the combustion chamber 11 is higher than the end away from the side wall of the combustion chamber 11.

[0037] Furthermore, in a preferred embodiment, any row of material conveying mechanisms includes: multiple drive shafts, which are located in the same plane and arranged parallel to each other. The two ends of each drive shaft are rotatably connected to the left and right side walls of the combustion chamber 11, respectively. The multiple drive shafts rotate synchronously in a clockwise or counterclockwise direction, and the rotation direction of the multiple drive shafts is the same as the conveying direction of the biomass fuel located above them.

[0038] Furthermore, in a preferred embodiment, it further includes: a packing breaker shaft 5 and a coke breaker shaft 106. The two ends of the packing breaker shaft 5 are rotatably connected to the left and right side walls of the combustion chamber 11, respectively. The two ends of the coke breaker shaft 106 are rotatably connected to the left and right side walls of the combustion chamber 11, respectively. Both the packing breaker shaft 5 and the coke breaker shaft 106 are located above the first chain grate 4. The packing breaker shaft 5 and the coke breaker shaft 106 rotate synchronously in a clockwise or counterclockwise direction. The rotation direction of the packing breaker shaft 5 and the coke breaker shaft 106 is the same as the conveying direction of the first chain grate 4.

[0039] Furthermore, in a preferred embodiment, it further includes: a baling straw feeder 2, which is used to transfer biomass fuel to the feed inlet 104 of the boiler body 1 and push it into the combustion chamber 11; the baling straw feeder 2 includes: a structural frame 21, baffles 22 and a hopper 23, the rear end of the structural frame 21 is connected to the feed inlet 104 of the boiler body 1, baffles 22 are installed on the left and right sides of the structural frame 21, the hopper 23 travels on the upper surface of the structural frame 21, and the hopper 23 is used to push the biomass fuel located on the structural frame 21 into the combustion chamber 11;

[0040] The bottom of the hopper 23 is equipped with wheels, and gears are rotatably mounted on the side of the hopper 23. The upper surface of the structural frame 21 is equipped with a rack, and the gears mesh with the rack. The hopper 23 moves on the structural frame 21 by driving the gears to rotate.

[0041] Furthermore, in a preferred embodiment, it further includes: water-cooled wall tubes 109, a boiler drum 108 is provided at the top of the heat exchange chamber 12, a combustion chamber 110 is provided on the front side of the heat exchange chamber 12, multiple water-cooled wall tubes 109 are evenly distributed on the left and right side walls of the boiler drum 108, the combustion chamber 110 and the combustion chamber 11, the multiple water-cooled wall tubes 109 are interconnected, a water inlet 111 communicating with the water-cooled wall tubes 109 is provided on the rear side wall of the combustion chamber 11, and a drain outlet and / or exhaust outlet communicating with the water-cooled wall tubes 109 are provided on the heat exchange chamber 12.

[0042] Furthermore, in a preferred embodiment, it further includes: a speed reducer 6, which is used to drive the furnace transmission system 3, the first chain grate 4, the second chain grate 113, the packing breaker shaft 5, and the coke breaker shaft 106.

[0043] Furthermore, in a preferred embodiment, the combustion chamber 11 is provided with an inclined preheating furnace arch 101 at the top front side, an inclined limiting furnace arch 102 at the top rear side, and an inclined burnout furnace arch 107 at the bottom of the combustion chamber 11. The preheating furnace arch 101 is located above the feed inlet 104; the burnout furnace arch 107 is located above the slag outlet; and air ducts 112 are provided on the left and right side walls of the combustion chamber 11.

[0044] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention.

[0045] Based on the above, this utility model also has the following embodiments:

[0046] In a further embodiment of this utility model, the biomass fuel burning on the second chain grate 113 generates high-temperature flue gas that can dry and preheat the biomass fuel entering through the feed inlet 104.

[0047] In a further embodiment of this utility model, the in-furnace transmission system 3 is used to repeatedly transfer biomass fuel and transfer the biomass fuel to the first chain grate 4; increasing the combustion stroke of the biomass fuel on the in-furnace transmission system 3, so that the biomass fuel can be fully burned.

[0048] In a further embodiment of this utility model, such as Figures 1 to 4 The diagram shows an indirect-coupled co-firing baled straw biomass direct-fired boiler with a row of material conveying mechanisms in the furnace transmission system 3. This embodiment is based on an indirect-coupled co-firing baled straw biomass direct-fired boiler with a row of material conveying mechanisms for explanation.

[0049] In a further embodiment of this utility model, the biomass direct-fired boiler structure of this utility model, which performs combustion work through multiple forward and reverse strokes inside the furnace, is composed of a straw baling feeder 2, a boiler body 1, an in-furnace transmission system 3, a matching fan, and a first chain grate 4.

[0050] In a further embodiment of this utility model, the baling straw feeder 2 uses a reciprocating mechanical transmission to perform work. The gear of the hopper 23 is driven by a motor or by an external chain drive to realize the reciprocating movement of the hopper 23 on the structural frame 21. The baling straw feeder 2 pushes the baled straw in the hopper into the feed inlet 104 at the front end of the boiler combustion chamber. After the feeding is completed, the hopper 23 returns to the starting point according to the original stroke. After new baled straw is put in, the previous operation is repeated.

[0051] In a further embodiment of this utility model, the structural frame 21 of the straw baling feeder 2 is constructed by welding together components such as I-beams and steel plates; the transmission system consists of components such as a motor, reducer, chain, directional wheel set, transmission gear, rack, transmission shaft, and bearings; the support structure is constructed by welding square steel, I-beams, embedded parts, and precast cement parts to the boiler body structure and the ground; the sealing structure is constructed by welding and assembling color steel plates and square steel to form an outer covering frame, with internal components such as a closed door, lighting, monitoring, and limiters. Through the combination and arrangement of each link, the work of conveying baled straw into the boiler body is ensured to be completed stably, efficiently, and cleanly within the constrained stroke.

[0052] In a further embodiment of this utility model, the baling straw feeder 2 is formed by welding together a frame component and a support component made of I-beams to form a main frame structure. The two ends are respectively connected to the lower end of the boiler main body feed port and the ground embedded part, ensuring the fatigue resistance and impact resistance of the main structure. Adding steel plate components to the main frame structure serves two purposes: firstly, it acts as a platform for the transported straw material; secondly, it isolates the transmission system components of the baling straw feeder from the transported straw material, preventing straw, leaves, and debris from falling into the transmission system components and causing equipment malfunction during transport.

[0053] In a further embodiment of this utility model, the transmission system consists of a motor and a reducer as the power source. A chain drives the transmission shaft to rotate, generating torsional force. This torsional force drives the gears on both sides of the equipment to rotate. The gears mesh with the rack and pinion, moving in a directional manner along the track established by the rack and pinion. The directional wheel set and gears form a triangular structure, ensuring stable movement of the equipment during directional movement and preventing derailment or self-spinning. The transmission system components are connected to the feeding hopper; the components' operation drives the feeding hopper to achieve the purpose of feeding materials.

[0054] In a further embodiment of this utility model, the sealing structure covers the main body of the baling straw feeder. On the one hand, it prevents the leaf fluff and slag generated during the movement of straw materials from scattering and causing environmental pollution. On the other hand, it also improves the overall aesthetics of the baling straw feeder. The sealed structure is equipped with lighting, monitoring, limiters and other components to realize the supporting facilities for digital, visual remote operation of the baling straw feeder. The sealing door is set in the three-dimensional space between the sealed structure and the baling straw feeder. Its working principle is that when the feeding hopper transports the baled straw to the feed inlet 104 of the boiler body 1, the sealing door closes and the boiler door opens at the same time. This prevents the high-temperature air inside the boiler from mixing with the low-temperature air outside, which would cause the boiler temperature to drop and affect the boiler's thermal efficiency. The sealing door can prevent backfire at the boiler feed inlet 104 and solve the safety hazard. The sealed structure is reasonably set with maintenance and cleaning channels to facilitate the boiler operator to maintain and repair the components of each part of the baling straw feeder.

[0055] In a further embodiment of this utility model, the boiler body 1, as the core equipment for burning straw baled fuel, is composed of three sections: boiler, furnace, and grate. The boiler body 1 adopts a longitudinally arranged horizontal fire tube structure, wherein the three-dimensional height of the combustion zone of the furnace body is increased, such as... Figures 1 to 4 As shown, a multi-stroke combustion-operated direct-fired boiler for baled straw biomass, with a row of material conveying mechanisms, forms two combustion layers by adding a drive shaft. At the same time, there is a gap between the drive shafts, which allows the baled straw fuel to be fully oxygenated during combustion. This structure can promote the complete combustion of straw.

[0056] In a further embodiment of this utility model, the structure is briefly described as follows: the pot body adopts a longitudinally arranged flue pipe outer pot cylinder 108, the pot cylinder 108 is provided with a header, and the pot cylinder 108 is provided with a water-cooled wall pipe 109 on the side, and the headers are arranged by a structure connected by a tube bundle; the furnace body is composed of a furnace door, a feed inlet, a front wall of the upper fire port, a furnace arch, a drive shaft assembly of the upper combustion zone, a water-cooled wall pipe 109, a header, a header connecting pipe, and other components; the first chain grate 4 is placed below the furnace body, and the grate surface and the furnace body form the lower combustion zone, i.e., the combustion chamber 11, and the straw burnt material is discharged into the slag remover through the grate slag outlet.

[0057] In a further embodiment of this utility model, multiple air ducts 112 are distributed between multiple rows of transmission shafts in the furnace transmission system 3, above and on both sides of the first chain grate 4.

[0058] In a further embodiment of this utility model, the objective is achieved as follows: the boiler body is designed as a multi-pass flue gas structure, through which superheated flue gas exchanges heat with components such as water-cooled walls, flue pipes, flue gas boxes, boiler drum, headers and connecting pipe bundles. A cast-in-place wall is added to the lower side of the boiler drum to realize a two-way flue gas path for superheated flue gas, thereby increasing the heat exchange area between the flue gas and the boiler body and reducing the exhaust temperature.

[0059] In a further embodiment of this utility model, the furnace body is designed as a double combustion chamber structure. A header and connecting pipe bundle are installed on the front wall of the upper fire port at the top of the furnace body and inside the furnace arch, constraining the path of superheated flue gas while participating in heat exchange. The inner sides of the water-cooled walls, connecting pipe bundles, and header components on the furnace body's perimeter are enclosed by refractory brick masonry. The bottom of the furnace body connects to the grate surface, thus forming the furnace combustion chamber structure. A drive shaft assembly is installed in the middle of the combustion chamber, dividing it into upper and lower parts. The straw-bundled fuel rotates and burns in both combustion chambers, releasing heat. Because the combustion chamber is entirely enclosed by a combination of refractory materials such as masonry and casting, the straw does not directly contact the water-cooled walls, connecting pipe bundles, headers, etc., during combustion. Instead, heat is uniformly conducted through the refractory materials, thus solving the problem of pipe bundle corrosion.

[0060] In a further embodiment of this utility model, after the straw baled fuel enters the boiler through the feed inlet, the furnace door is closed by a motor. The furnace door and the feed inlet are connected to the boiler body by a flexible connecting pipe bundle and a connecting pipe bundle, and water is supplied. The heat released by the straw baled fuel entering the boiler and starting to burn can be exchanged between the furnace door and the feed inlet.

[0061] In a further embodiment of this invention, the baled straw fuel enters the upper combustion zone through the furnace door to begin preheating and combustion, and then moves at a constant speed towards the rear of the combustion chamber via a drive shaft structure. The drive shaft is arranged in a stepped, horizontal configuration towards the rear of the boiler to form a grate structure. The length of the drive shaft is greater than the width of the boiler. Sealed water boxes are installed at both ends of the shaft extending outside the furnace, and water pipes are connected to them. The shaft rotation is powered by an electric motor and a reducer. This power is converted into torque through a sprocket assembly and gears, driving the shaft to rotate in a directional and constant-speed manner. This design solves the problem of baled straw fuel stacking and compressing into a furnace arch during combustion in the upper combustion zone due to lack of stroke power, completely eliminating the risk of boiler component damage and smoke escaping from the furnace due to poor ventilation.

[0062] In a further embodiment of this invention, after the baled straw fuel travels from the upper combustion zone to the end of the upper combustion chamber, the unburned baled straw fuel falls into the lower combustion chamber. The lower combustion chamber is driven by the first chain grate 4 to move the unburned baled straw fuel towards the ash discharge port at a uniform speed. During this movement, the bale-breaking shaft 5 works to evenly spread the unburned baled straw fuel for continued combustion, while the coke-breaking shaft 106 works to break and disperse the remaining coke residue into ash blocks that meet the ash discharge requirements and are discharged from the boiler. The rotation direction of the baled straw shaft 5 and the coke-breaking shaft 106 is the same as that of the drive wheel / driven wheel of the first chain grate 4. The surfaces of the baled straw shaft 5 and the coke-breaking shaft 106 inside the furnace are fitted with teeth of varying lengths by a welding machine. The rotation of the baled straw shaft 5 and the coke-breaking shaft 106 drives the teeth to do work to achieve the design requirements. The work of the baled straw shaft 5 can evenly spread the straw baled fuel that has been burned into an irregular shape. This design makes it easy for the straw baled fuel with a moisture content that exceeds the standard and is not easy to burn out to come into contact with sufficient oxygen and absorb the heat of the furnace to quickly dry and gasify for combustion. The work of the coke-breaking shaft 106 can break the slag blocks that are too large after the straw baled fuel is burned out into slag blocks that meet the discharge standards of the slag discharge machine. This design facilitates slag discharge and reduces the failure rate of the slag removal equipment.

[0063] In a further embodiment of this utility model, as described above, the biomass direct-fired boiler structure, which employs multiple forward and reverse strokes within the furnace for combustion, relaxes the standards for using straw as raw material. This increases the range of choices available to users during raw material collection and storage, reducing procurement costs. The baled straw fuel burns completely during combustion, reducing straw consumption. Simultaneously, the fully burned straw produces less ash, reducing slag emissions and minimizing unburned fuel due to high moisture content. The straw does not pile up or compress during combustion, eliminating safety hazards and reducing equipment failure rates. The combination of a drive shaft assembly and a grate to constrain the stroke ensures that the straw does not pile up or compress during combustion, fundamentally eliminating boiler safety hazards caused by non-human error.

[0064] In a further embodiment of this utility model, as summarized above, the biomass direct-fired boiler structure, which employs multiple forward and reverse strokes within the furnace for combustion, can broaden the range of raw material acquisition, save on raw material procurement costs, and reduce raw material consumption. Simultaneously, it eliminates production safety hazards and reduces equipment failure rates. Fundamentally, it achieves the economic goal of cost reduction and efficiency improvement in heating production, while ensuring the property safety of heating equipment and the life safety of boiler operators.

[0065] In a further embodiment of this utility model, multiple air ducts 112 are distributed between multiple rows of drive shafts in the furnace transmission system 3, above and on both sides of the chain grate 4.

[0066] In a further embodiment of this utility model, two sets of grates are designed to be combined into a grate assembly with their tails facing each other to work together. The grate assembly is placed below the boiler body 1, wherein the second chain grate 113 is used to burn biomass briquettes; and the first chain grate 4 is used to burn straw baled fuel. The two sets of grates face each other at their tails and share a single slag discharge machine.

[0067] In a further embodiment of this utility model, the second chain grate 113 is located on the front side and is equipped with a biomass briquette fuel feeder. The feeder is located below the baled straw feeder 2 and feeds fuel into the feeding hopper 114 via a conveyor belt mechanism. The overall size of the second chain grate 113 is smaller than that of the first chain grate 4. A furnace arch is set on the top of the second chain grate 113, and masonry covering is provided on both sides and the front wall to form an independent combustion chamber. No water-cooled walls or connecting tube bundles are installed around the combustion chamber for heat exchange. The area directly above the structure of the second chain grate 113 is between the boiler feed inlet and the upper fire outlet. The first chain grate 4 is located behind the second chain grate 113 and its overall size is larger than that of the second chain grate 113.

[0068] In a further embodiment of this utility model, during operation, the second chain grate 113 does not have water-cooled walls and connecting tube bundles installed in its chamber structure. Therefore, the superheated flue gas generated by fuel combustion does not undergo heat exchange in its combustion chamber, but instead directly enters the corresponding upper combustion chamber through the upper fire port at the front end of the furnace arch.

[0069] In a further embodiment of this invention, according to the principle of energy conservation, when straw baled fuel with excessive moisture content enters the boiler for combustion, it does not first release heat, but rather absorbs heat to evaporate moisture and dry itself. Only after drying to the point where it can self-ignite can it burn and release heat. Throughout this process, the temperature inside the boiler will inevitably decrease because the straw with excessive moisture content absorbs heat and dries itself. In practice, this phenomenon will be particularly pronounced when using straw baled fuel with a moisture content of around 60%, severely affecting heat conversion efficiency. Because the entire heat absorption process is continuous, it is easy for the proportion of heat released by straw combustion to be lower than the heat absorbed by the straw with excessive moisture content during self-drying, resulting in the boiler continuously consuming straw but failing to produce heat. Meanwhile, as the boiler combustion chamber temperature continues to decrease, it cannot meet the requirement that the moisture released during the drying process of the straw with excessive moisture content be vaporized and participate in combustion. As the moisture is conducted through the boiler and discharged into the atmosphere along with the flue gas, it continues to absorb heat. When passing through components such as flue pipes, ductwork, dust collectors, and induced draft fans, it adheres to these components, causing corrosion, damaging related equipment, accelerating aging, and reducing service life. When excessive moisture enters the chimney, it immediately turns into water mist, adheres to the inner wall of the chimney, forms condensate, and flows downwards to the base of the chimney, continuing to corrode the chimney and creating serious safety hazards.

[0070] In a further embodiment of this utility model, as described above, the core purpose of adding a new combustion system to the original boiler structure is to solve the hidden danger caused by insufficient heat replenishment in the boiler combustion chamber when excessive heat is absorbed during the burning of straw with excessive moisture content.

[0071] In a further embodiment of this invention, the superheated flue gas released during the combustion of biomass briquettes by the second chain grate 113 and its corresponding combustion chamber directly enters the combustion chamber where the straw baled fuel is used for work without heat exchange, thus solving the aforementioned problem. This replenishes the heat consumed in the combustion chamber where the straw baled fuel is used for work. By continuously adjusting the consumption of biomass briquettes, the temperature in the combustion chamber where the straw baled fuel is used for work is maintained within the required temperature range. This not only dries the straw baled fuel with excessive moisture but also ensures the gasification requirements after water vapor evaporation. This ensures that the consumed fuel is not wasted, turning the moisture in the straw baled fuel into valuable energy through complete heat conversion.

[0072] The above are merely preferred embodiments of the present utility model and are not intended to limit the implementation methods and protection scope of the present utility model. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An indirectly coupled co-firing type bundled straw biomass direct combustion boiler, characterized by, include: The boiler body (1) has a combustion chamber (11) and a heat exchange chamber (12) inside. The heat exchange chamber (12) is located on the upper side of the combustion chamber (11) and is connected to the combustion chamber (11). The side wall of the combustion chamber (11) is provided with a feed inlet (104) and a feeding hopper (114); the side wall of the heat exchange chamber (12) is provided with a smoke outlet (105). It also includes: an in-furnace drive system (3), a first chain grate (4) and a second chain grate (113), both of which are installed at the bottom of the combustion chamber (11). The in-furnace drive system (3) is installed in the combustion chamber (11) and located above the first chain grate (4). The in-furnace drive system (3) is used to transfer the biomass fuel filled by the feed port (104) to the first chain grate (4) to achieve full combustion of the biomass fuel. The feed hopper (114) is used to add biomass fuel to the second chain grate (113). The bottom of the combustion chamber (11) is provided with a slag outlet, which is located between the first chain grate (4) and the second chain grate (113). Both the first chain grate (4) and the second chain grate (113) are used to transfer the fully burned biomass fuel located above them to the slag outlet.

2. The indirectly coupled co-fired straw bale biomass boiler of claim 1, wherein, The feed inlet (104) and the feeding hopper (114) are both located on the front side wall of the combustion chamber (11) and the feeding hopper (114) is located below the feed inlet (104). The first chain grate (4) is located near the rear side wall of the combustion chamber (11) and the second chain grate (113) is located near the front side wall of the combustion chamber (11).

3. The indirectly coupled co-fired straw bale biomass boiler of claim 2, wherein, The in-furnace transmission system (3) includes: at least one row of material conveying mechanisms, and multiple rows of material conveying mechanisms arranged sequentially from top to bottom; the front end of the material conveying mechanism located at the top layer is set close to the front side wall of the combustion chamber (11) and located below the feed inlet (104); the front end of the material conveying mechanism located at the bottom layer is set close to the front side wall of the combustion chamber (11); when the front end or rear end of any row of material conveying mechanisms is set close to the side wall of the combustion chamber (11), its other end is provided with a gap from the side wall of the combustion chamber (11), and the gap size is greater than the maximum size of biomass fuel.

4. The indirectly coupled co-fired straw bale biomass boiler of claim 3, wherein, For any two adjacent rows of material conveying mechanisms, if the front end of one row of material conveying mechanisms is located close to the front side wall of the combustion chamber (11), then the rear end of the other row of material conveying mechanisms is located close to the rear side wall of the combustion chamber (11).

5. The indirectly coupled co-fired straw bale biomass boiler of claim 3, wherein, Any row of material conveying mechanisms includes: multiple drive shafts, which are located in the same plane and are arranged in parallel to each other. The two ends of each drive shaft are rotatably connected to the left and right side walls of the combustion chamber (11), respectively. The multiple drive shafts rotate synchronously in a clockwise or counterclockwise direction, and the rotation direction of the multiple drive shafts is the same as the transfer direction of the biomass fuel located above them.

6. The indirect-coupled co-firing type direct-fired boiler for baled straw biomass according to claim 2, characterized in that, Also includes: The two ends of the packing breaker (5) and the coke breaker (106) are rotatably connected to the left and right side walls of the combustion chamber (11), respectively. The two ends of the coke breaker (106) are rotatably connected to the left and right side walls of the combustion chamber (11), respectively. The packing breaker (5) and the coke breaker (106) are both located above the first chain grate (4). The packing breaker (5) and the coke breaker (106) rotate synchronously in a clockwise or counterclockwise direction. The rotation direction of the packing breaker (5) and the coke breaker (106) is the same as the conveying direction of the first chain grate (4).

7. The indirectly coupled co-fired straw bale biomass boiler of claim 2, wherein, Also includes: A baling straw feeder (2) is used to transfer biomass fuel to the feed inlet (104) of the boiler body (1) and push it into the combustion chamber (11); the baling straw feeder (2) includes: a structural frame (21), a baffle (22) and a hopper (23). The rear end of the structural frame (21) is connected to the feed inlet (104) of the boiler body (1). Baffles (22) are installed on the left and right sides of the structural frame (21). The hopper (23) travels on the upper surface of the structural frame (21). The hopper (23) is used to push the biomass fuel located on the structural frame (21) into the combustion chamber (11); The bottom of the hopper (23) is equipped with wheels, and gears are rotatably mounted on the side of the hopper (23). The upper surface of the structural frame (21) is equipped with a rack, and the gear meshes with the rack. The hopper (23) moves on the structural frame (21) by driving the gear to rotate.

8. The indirectly coupled co-fired straw bale biomass boiler of claim 2, wherein, Also includes: The top of the heat exchange chamber (12) is provided with a boiler drum (108), and the front side of the heat exchange chamber (12) is provided with a combustion chamber (110). The left and right side walls of the boiler drum (108), the combustion chamber (110) and the combustion chamber (11) are evenly provided with multiple water cooling wall tubes (109). The rear side wall of the combustion chamber (11) is provided with a water inlet (111) that communicates with the water cooling wall tube (109). The heat exchange chamber (12) is provided with a drain outlet and / or exhaust outlet that communicates with the water cooling wall tube (109).

9. The indirectly coupled co-fired straw bale biomass boiler of claim 2, wherein, Also includes: The speed reducer unit (6) is used to drive the furnace transmission system (3), the first chain grate (4), the second chain grate (113), the packing shaft (5), and the coke breaking shaft (106).

10. The indirectly coupled co-fired straw bale biomass boiler of claim 1, wherein, The combustion chamber (11) has an inclined preheating furnace arch (101) at the top front side, an inclined limiting furnace arch (102) at the top rear side, and an inclined burnout furnace arch (107) at the bottom. The preheating furnace arch (101) is located above the feed inlet (104); the burnout furnace arch (107) is located above the slag outlet; and air ducts (112) are provided on the left and right side walls of the combustion chamber (11).

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