Integrated biomass boiler fuel feeding and drying system

Abstract

The invention provides an integral biomass boiler fuel feeding and drying system. According to the drying system, the feeding device, the drying device, the boiler body and the smoke exhaust device are integrated together, and the chain grate stoker of the boiler body extends forwards all the time into the drying device and the feeding device, so that fuel feeding, drying and combustion are carried out synchronously during working, the occupied space for fuel stacking is saved, and the storage risk of fuel is reduced; besides, the drying device is divided into the drying heat exchange chamber and the hot smoke distribution chamber by the chain grate stoker, and the drying heat exchange chamber and the hot smoke distribution chamber are respectively communicated with the smoke exhaust pipeline, so that smoke with waste heat discharged by the boiler body can be utilized to take away moisture in fuel, then the moisture is discharged to the smoke exhaust pipeline at the tail, and the moisture in the fuel is prevented from entering a hearth to participate in combustion. The combustion efficiency is improved, the high-moisture biomass fuel is dried through smoke waste heat, the energy utilization rate is increased, meanwhile, the smoke exhaust temperature is lowered, and pollution to the environment is reduced.

Description

[0001] The present application is a divisional application of the invention patent application with the patent application number 2025107277066, the patent application date of June 3, 2025, and the invention patent application name of Whole biomass boiler fuel feeding and drying system and control method thereof. TECHNICAL FIELD

[0002] The present application relates to the technical field of biomass boiler, in particular to a whole biomass boiler fuel feeding and drying system. BACKGROUND

[0003] Biomass chain boiler is a layer combustion boiler that takes biomass fuel as the core energy source, and its specific structural design makes it have unique advantages in combustion control, fuel adaptability and environmental protection performance: (1) The chain grate mainly adopts layer combustion, and the fuel forms a stable combustion layer on the grate, while the lighter volatile matter and fine particles are suspended and burned in the furnace. This mixed combustion mode prolongs the residence time of the fuel, ensuring that the volatile matter (about 70-80% of the biomass heat value) is fully burned, and the burnout rate can reach more than 90%. (2) By arranging a multi-stage secondary air system in the furnace, the air ratio can be accurately controlled: the primary air is sent from the bottom of the grate to support layer combustion; the secondary air is injected from the upper part of the furnace at high speed to enhance air flow disturbance and promote the mixing of volatile matter and air, thereby inhibiting the generation of nitrogen oxides. (3) A PLC control system is used to automatically adjust the grate moving speed, air supply and fuel feeding according to the fuel state and load demand. (4) It can adapt to various biomass fuels, including agricultural waste (straw, rice husk, corn cob, etc.), forestry residues (sawdust, bark, branches, etc.), processing by-products (bagasse, fruit shells, hemp rods, etc.), and shaped fuels (granular or briquetted biomass with moisture content ≤40%). (5) Good tolerance to fuel characteristics: through the preheating and drying zone at the front end of the furnace and the design of the super-large combustion chamber, fuels with moisture content up to 40-50% can be processed; different types and forms of biomass can be co-fired, such as mixed combustion of bark and straw; it is suitable for granules with a particle size of ≤50mm, which can avoid fine fuel leakage (which needs to be pressed into granules). At present, biomass chain boilers have become the preferred solution in the small and medium-sized heating field due to their wide fuel adaptability, significant environmental protection benefits and high automation level, and are widely used in agricultural processing parks, regional heating and other scenarios. With the upgrading of combustion control technology (such as AI optimized air distribution) and pollution co-processing systems (such as SNCR denitrification), the penetration rate of biomass chain boilers in the large industrial boiler market is expected to further increase in the future.

[0004] In practical applications, technicians have adopted a design that incorporates a preheating and drying zone and an extra-large combustion chamber at the front end of the furnace for burning biomass fuels with a moisture content as high as 40-50%. While this has achieved some success, it also presents the following drawbacks: 1) Low combustion efficiency: High-moisture biomass fuels have a lower calorific value, and the evaporation of moisture consumes a large amount of heat, leading to decreased combustion efficiency and significantly increasing fuel costs for users. 2) Risk of grate vibration and deflagration: High fuel moisture content can exacerbate grate vibration and even trigger deflagration in the furnace, threatening the safe operation of the boiler. 3) Flue gas disturbance and high ash carbon content: Fuels with high moisture content produce a large amount of water vapor during combustion, disrupting flue gas flow, increasing the carbon content of ash, and further reducing boiler efficiency. 4) Incomplete combustion: Fuels with high evaporation content release a large amount of water vapor during combustion, lowering the combustion temperature, affecting the completeness of combustion, and leading to increased heat loss and emissions. 5) Poor combustion stability: Fuels with high evaporation content are prone to instability in the combustion process, potentially causing problems such as flame extinction and uneven combustion, affecting the stability of the boiler load. In summary, using chain grate boilers to burn high-moisture biomass fuels encounters a series of problems, including low combustion efficiency, increased safety hazards, exacerbated environmental pollution, and decreased operational stability. These issues not only affect the normal operation and thermal efficiency of the boiler but may also lead to additional safety risks and economic burdens. Therefore, appropriate technical measures and management strategies are needed to address these challenges in practical applications. Summary of the Invention

[0005] This invention provides an integrated biomass boiler fuel feeding and drying system to address the aforementioned problems in the prior art. The integrated biomass boiler fuel feeding and drying system of this invention is suitable for high-moisture biomass fuels. This system integrates the feeding device, drying device, boiler body, and flue gas system, saving space and reducing costs. Furthermore, the chain grate of the boiler body extends forward into the drying and feeding devices, allowing fuel supply, drying, and combustion to occur simultaneously during operation. After drying, the fuel is directly fed into the furnace for combustion, saving space occupied by fuel storage, reducing storage risks, and facilitating control. In addition, the drying device is divided into a drying heat exchange chamber and a hot flue gas distribution chamber by the chain grate, both connected to the flue gas duct. This allows the waste heat from the boiler body to carry away moisture from the fuel before discharging it into the exhaust duct, preventing moisture from entering the furnace and participating in combustion, thus improving combustion efficiency. Utilizing waste heat from the flue gas to dry high-moisture fuel improves energy utilization and reduces flue gas temperature, minimizing environmental pollution.

[0006] The technical solution of this invention is as follows:

[0007] An integrated biomass boiler fuel feeding and drying system includes a feeding device, a drying device, a boiler body, and a flue gas system arranged sequentially. The flue gas system includes a flue gas duct and an exhaust fan. The feeding device includes a stockpile with a feed inlet at the top and a distributor inside the feed inlet. The boiler body has a furnace inside, with a chain grate at the bottom. The chain grate is connected to a drive device and can move under the drive. The front end of the chain grate extends forward into the interior of the stockpile, dividing the drying device into a drying heat exchange chamber and a hot flue gas distribution chamber. The stockpile, drying heat exchange chamber, and furnace are interconnected. The hot flue gas distribution chamber is connected to the flue gas duct via a hot flue gas pipe. A hot flue gas conveying fan is installed on the hot flue gas duct to draw the flue gas containing waste heat from the flue gas duct to the hot flue gas distribution chamber. The drying heat exchange chamber is connected to the flue gas duct via a waste gas pipe. The connection point between the hot flue gas duct and the flue gas duct is located in front of the connection point between the waste gas pipe and the flue gas duct.

[0008] Compared with existing technologies, the integrated biomass boiler fuel feeding and drying system of the present invention is suitable for high-moisture biomass fuel. This system integrates the feeding device, drying device, boiler body, and flue gas system, with the chain grate of the boiler body extending forward into the drying and feeding devices. This allows for simultaneous fuel supply, drying, and combustion during operation, facilitating control. Furthermore, the fuel, after drying, is directly fed into the furnace for combustion, saving space and reducing storage risks. In addition, the drying device is divided into a drying heat exchange chamber and a hot flue gas distribution chamber by the chain grate, both connected to the flue gas duct. This allows the waste heat from the boiler body to carry away moisture from the fuel before discharging it into the exhaust duct, preventing moisture from entering the furnace and participating in combustion, thus improving combustion efficiency. Utilizing waste heat from the flue gas to dry high-moisture fuel also improves energy utilization and reduces flue gas temperature, minimizing environmental pollution.

[0009] As an optimization, in the aforementioned integrated biomass boiler fuel feeding and drying system, a baffle gate is provided between the stockpile and the drying heat exchange chamber, and the baffle gate is equipped with an adjustment mechanism. The adjustment mechanism is electrically connected to the control system and is used to drive the baffle gate to move up and down to adjust the gap between the baffle gate and the chain grate. Therefore, before fuel combustion, the gap between the baffle gate and the chain grate can be automatically adjusted according to the moisture content of the biomass fuel, and during fuel combustion, according to the pressure of the steam produced by the boiler body, to ensure the fuel feed rate.

[0010] Furthermore, the stockpile is equipped with a material level detector to detect the amount of material entering the stockpile and maintain the material level within a set position. This stable material level provides stable static pressure for the fuel to be smoothly and evenly distributed into the chain grate inside the boiler body through the mechanical baffle gate; it also ensures a balance between the feed rate and the boiler's combustion consumption.

[0011] As an optimization, in the aforementioned integrated biomass boiler fuel feeding and drying system, the top of the drying heat exchange chamber is equipped with a fume hood. The fume hood is trapezoidal in shape, wider at the bottom and narrower at the top, and its outlet is connected to the exhaust gas pipe. This allows the exhaust gas to be guided to the exhaust gas pipe more quickly after entering the fume hood, reducing the residence time of the exhaust gas inside the fume hood and thus improving the exhaust efficiency.

[0012] Furthermore, a temperature detector is installed at the outlet of the fume hood, and a flow regulating valve is installed at the outlet of the hot flue pipe; the temperature detector and the flow regulating valve are electrically connected to the control system. After the hot flue dries the fuel, it carries away the moisture in the fuel, becoming exhaust gas, which is in a steam-saturated state. By measuring the temperature of the exhaust gas at the outlet of the fume hood, the net amount of moisture carried by the exhaust gas can be calculated, thereby determining the moisture content in the fuel. Based on the moisture content, the opening size of the flow regulating valve can be adjusted to regulate the amount of hot flue gas entering the hot flue distribution chamber, ensuring the drying effect.

[0013] Furthermore, the exhaust hood is equipped with a filter screen at its outlet. This allows impurities in the exhaust gas to be filtered out before being released outdoors, thus further reducing environmental pollution.

[0014] As an optimization, in the aforementioned integrated biomass boiler fuel feeding and drying system, a water-cooled fire damper is provided between the drying heat exchange chamber and the furnace. The water-cooled fire damper can shield the biomass fuel in the drying heat exchange chamber from flame radiation inside the furnace, thereby increasing the operational reliability of the drying system of the present invention.

[0015] As an optimization, in the aforementioned integrated biomass boiler fuel feeding and drying system, the distributor is conical. The conical structure can naturally guide the fuel from the center to the surrounding area, avoiding accumulation in a single area, ensuring uniform load on the combustion cross-section inside the furnace, and reducing local high temperature or unburned phenomena; moreover, the inclination angle of the conical surface is usually ≥60°, thereby utilizing gravity flow to reduce fuel adhesion or retention, which is suitable for distributing high-moisture biomass fuel.

[0016] The control method of the aforementioned integrated biomass boiler fuel feeding and drying system is as follows: First, based on the moisture content of the biomass fuel, the control system controls the regulating mechanism to adjust the gap between the baffle gate and the chain grate, and sets the operating speed of the chain grate; during boiler operation, the control system controls the distributor, hot flue gas conveying fan, exhaust fan, and drive device to start synchronously; after the high-moisture biomass fuel is conveyed to the top of the stockpile, it enters the feed inlet and falls evenly into the stockpile under the action of the distributor. During this process, the material level detector monitors the amount of fuel entering the stockpile in real time, keeping the material level within the set position to ensure a balance between the feed rate and the boiler's combustion consumption; the drive device drives the chain grate to move evenly from front to back, moving the fuel in the stockpile backward and through the baffle gate into the drying and heat exchange chamber. Under the obstruction of the baffle gate, the fuel forms a uniform, flat layer, spreading evenly on the surface of the chain grate; the hot flue gas conveying fan extracts the hot flue gas from the exhaust pipe, and... The hot flue gas is transported to the hot flue gas distribution chamber through a hot flue pipe. After entering the hot flue gas distribution chamber, the hot flue gas moves upward, passes through the chain grate, exchanges heat with the fuel on the grate surface, and removes moisture from the fuel. At this time, the hot flue gas becomes low-temperature exhaust gas and continues to move upward, flowing out of the drying heat exchange chamber and finally flowing back into the exhaust gas pipe through the exhaust gas pipe, and is discharged outdoors by the exhaust fan. The fuel dried by the hot flue gas continues to move backward with the chain grate and enters the furnace for combustion and heat release. The hot flue gas generated by combustion enters the exhaust gas pipe. During the fuel combustion process, if the pressure of the steam produced by the boiler body is detected to be less than the set value, the control system controls the regulating mechanism to start, driving the baffle gate to rise, increasing the gap between the baffle gate and the chain grate, and increasing the fuel feed rate. At the same time, the control system calculates the net amount of moisture carried by the exhaust gas based on the exhaust gas temperature at the outlet of the drying heat exchange chamber detected by the temperature detector, and adjusts the opening size of the flow regulating valve accordingly, thereby adjusting the amount of hot flue gas entering the hot flue gas distribution chamber to ensure the drying effect.

[0017] During the process of dry flue gas flowing from the hot flue duct into the hot flue distribution chamber and then flowing out from the drying heat exchange chamber into the exhaust gas duct, a slight positive pressure is formed in the drying heat exchange chamber, which can prevent the flame in the furnace from backfireing into the drying heat exchange chamber.

[0018] The control method of the integrated biomass boiler fuel feeding and drying system of this application controls the synchronous start-up of the distributor, hot flue gas conveying fan, exhaust fan and drive device, so that fuel supply, drying and combustion can be carried out simultaneously. Each link does not need to be controlled by logic, which is convenient and easy to implement. At the same time, during the fuel combustion process, the gap between the baffle gate and the chain grate is adjusted according to the pressure of the steam produced by the boiler body, and the net amount of moisture carried by the exhaust gas is calculated according to the temperature of the exhaust gas at the outlet of the drying heat exchange chamber, and the amount of hot flue gas entering the hot flue gas distribution chamber is adjusted, thereby ensuring the drying effect of the fuel and improving the combustion efficiency. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the integrated biomass boiler fuel feeding and drying system of this application;

[0020] Figure 2 This is a schematic diagram of the integrated biomass boiler fuel feeding and drying system of this application.

[0021] The labels in the attached diagram are as follows: 1-Feeding device, 11-Stockpile silo, 12-Inlet, 13-Distributor, 14-Level detector; 2-Drying device, 201-Drying heat exchange chamber, 202-Hot smoke distribution chamber, 21-Hot smoke duct, 22-Hot smoke conveying fan, 23-Exhaust gas duct, 24-Fumigation hood, 25-Temperature detector, 26-Flow regulating valve, 27-Filter screen; 3-Boiler body, 301-Furnace, 31-Chain grate, 311-Grate combustion zone, 312-Grate burnout zone; 4-Exhaust device, 41-Exhaust duct, 42-Exhaust fan; 5-Drive device; 6-Baffle gate; 7-Water-cooled fire baffle. Detailed Implementation

[0022] The technical solution of the present invention will be further described in detail below through specific embodiments and with reference to the accompanying drawings, but these should not be construed as limiting the present invention. Contents not described in detail in the following embodiments are all common knowledge in the art.

[0023] See Figure 1 and Figure 2 ( Figure 1(In the image, part of the outer shell has been removed to demonstrate the internal structure of the device). The integrated biomass boiler fuel feeding and drying system of the present invention includes a feeding device 1, a drying device 2, a boiler body 3, and a flue gas device 4 arranged in sequence. The flue gas device 4 includes a flue gas pipe 41 and an exhaust fan 42. The feeding device 1 includes a stacking bin 11. A feeding inlet 12 is provided above the stacking bin 11, and a distributor 13 is provided inside the feeding inlet 12. The boiler body 3 includes a furnace 301 inside, and a chain grate 31 is provided at the bottom of the furnace 301. The chain grate 31 is connected to a drive device 5 and can move under the drive of the drive device 5. The front end of the chain grate 31... Extending forward to the bottom of the stockpile 11, the drying device 2 is divided into a drying heat exchange chamber 201 and a hot smoke distribution chamber 202; the stockpile 11, the drying heat exchange chamber 201, and the furnace 301 are interconnected; the hot smoke distribution chamber 202 is connected to the exhaust pipe 41 through a hot smoke pipe 21; a hot smoke conveying fan 22 is provided on the hot smoke pipe 21 to draw the flue gas containing waste heat from the exhaust pipe 41 into the hot smoke distribution chamber 202; the drying heat exchange chamber 201 is connected to the exhaust pipe 41 through a waste gas pipe 23; the connection position of the hot smoke pipe 21 and the exhaust pipe 41 is located in front of the connection position of the waste gas pipe 23 and the exhaust pipe 41.

[0024] The integrated biomass boiler fuel feeding and drying system of the present invention systematically integrates the boiler body 3 (including chain grate and matching furnace arch, secondary air, etc.) with the feeding device 1. On the one hand, it makes full use of the original boiler body's power, control system, and feeding and distribution functions. On the other hand, by setting a drying device 2 between the boiler body 3 and the feeding device 1, and extending the chain grate 31 of the boiler body 3 forward into the drying device 2 and the feeding device 1, fuel supply, drying, and combustion are carried out simultaneously during operation, saving fuel storage space and reducing fuel storage risks. Moreover, the drying device 2 is divided by the chain grate 31 into a drying heat exchange chamber 201 and a hot flue gas distribution chamber 2. 02, and connected to the flue gas duct 41 respectively, so that the waste heat flue gas discharged from the boiler body 3 can carry away the moisture in the fuel and discharge it to the flue gas duct 41 at the tail end. This avoids the moisture in the fuel entering the furnace 301 to participate in combustion and heat exchange. Moreover, since the moisture in the fuel is evaporated, the low moisture fuel enters the boiler body 3 for combustion, heat release and heat transfer, which greatly gives full play to the advantages of the chain grate biomass combustion boiler: high efficiency, environmental protection, strong fuel adaptability, convenient operation and high degree of automation. It solves a series of problems existing in the chain grate boiler using high moisture biomass fuel, such as low combustion efficiency, increased safety hazards, aggravated environmental pollution and deterioration of operation stability.

[0025] In the prior art, the chain grate area in the furnace 301 of a boiler body using high-moisture biomass fuel can be divided into a grate combustion zone 311 and a grate burnout zone 312, with the burnout zone 312 typically accounting for more than 50% of the total grate length. In this invention, after the high-moisture biomass fuel is dried using the drying device 2, the moisture content of the fuel is significantly reduced, improving its combustion efficiency in the boiler body 3 (the combustion efficiency can be increased by more than 3%). Therefore, the length of the burnout zone 312 in the boiler body 3 of this invention can be reduced by about 50% (i.e., the burnout zone 312 accounts for more than 25% of the total grate length), thereby reducing the cost of the boiler body 3. At the same time, the uncontrollable excess air in the burnout zone 312 can be reduced by more than 30%, optimizing the amount of combustion air.

[0026] Example:

[0027] In this embodiment, a baffle gate 6 is provided between the stockpile 11 and the drying heat exchange chamber 201, and an adjustment mechanism is provided on the baffle gate 6. The adjustment mechanism is electrically connected to the control system and is used to drive the baffle gate 6 to move up and down to adjust the gap between the baffle gate 6 and the chain grate 31. Thus, before fuel combustion, the gap between the baffle gate 6 and the chain grate 31 can be automatically adjusted according to the moisture content of the biomass fuel, and during fuel combustion, according to the pressure of the steam produced by the boiler body 3, to ensure the fuel feed rate.

[0028] Furthermore, the stockpile 11 is equipped with a level detector 14 to detect the amount of fuel entering the stockpile 11 and maintain the level within a set position. The stable level provides stable static pressure for the fuel to be smoothly and evenly spread into the chain grate 31 inside the boiler body 3 through the mechanical baffle gate, and also ensures the balance between the feed rate and the combustion consumption of the boiler body 3.

[0029] In this embodiment, the top of the drying heat exchange chamber 201 is provided with a fume hood 24. The fume hood 24 is trapezoidal in shape, wider at the bottom than at the top, and its outlet is connected to the exhaust gas pipe 23. This allows the exhaust gas to be guided to the exhaust gas pipe 23 more quickly after entering the fume hood 24, reducing the residence time of the exhaust gas inside the fume hood 24 and thus improving the exhaust efficiency.

[0030] Furthermore, a temperature detector 25 is installed at the outlet of the fume hood 24, and a flow regulating valve 26 is installed at the outlet of the hot smoke duct 21. The temperature detector 25 and the flow regulating valve 26 are electrically connected to the control system. After the hot smoke dries the fuel, it carries away the moisture in the fuel and becomes exhaust gas, which is in a steam-saturated state. By measuring the temperature of the exhaust gas at the outlet of the fume hood 24, the net amount of moisture carried by the exhaust gas can be calculated. Therefore, the opening size of the flow regulating valve 26 can be adjusted according to the moisture content to adjust the amount of hot smoke entering the hot smoke distribution chamber 202 and ensure the drying effect.

[0031] Furthermore, the exhaust hood 24 is equipped with a filter screen 27 at its outlet. This allows impurities in the exhaust gas to be filtered out before being released outdoors, thus further reducing environmental pollution.

[0032] In this embodiment, a water-cooled fire baffle 7 is provided between the drying heat exchange chamber 201 and the furnace 301 to shield the flame radiation in the furnace 301 from the fuel in the drying heat exchange chamber 201, thereby increasing the operational reliability of the drying system of the present invention.

[0033] In this embodiment, the feeder 13 is conical. The conical structure can naturally guide the fuel from the center to the surrounding area, avoiding accumulation in a single area, ensuring uniform load on the combustion cross section in the furnace, and reducing local high temperature or unburned phenomena; moreover, the inclination angle of the conical surface is usually ≥60°, so that gravity can be used for self-flow, reducing fuel adhesion or retention, which is suitable for the feeding operation of high moisture biomass fuel.

[0034] The control method of the integrated biomass boiler fuel feeding and drying system in this embodiment is as follows.

[0035] First, based on the moisture content of the high-moisture biomass fuel, the control system adjusts the gap between the baffle gate 6 and the chain grate 31 by controlling the regulating mechanism, and sets the operating speed of the chain grate 31 (for example, when the moisture content is high, the gap between the baffle gate 6 and the chain grate 31 is reduced, at which time the material layer thickness is lower and the drying resistance is lower, while the operating speed of the chain grate 31 is increased to ensure the feed rate).

[0036] During boiler body 3 operation, the control system synchronously starts the distributor 13, hot flue gas conveying fan 22, exhaust fan 42, and drive device 5. High-moisture biomass fuel is conveyed (by a separately equipped feeding device) above the stockpile 11, enters the feed inlet 12, and falls evenly into the stockpile 11 under the action of the distributor 13. During this process, the level detector 14 monitors the amount of fuel entering the stockpile 11 in real time, maintaining the level within the set position to ensure a balance between the feed rate and the combustion consumption of the boiler body 3. The drive device 5 drives the chain grate 31 to move evenly from front to back, moving the fuel in the stockpile 11 backward and through the baffle gate 6 into the drying heat exchange chamber 201. The fuel passes through the baffle gate 6... Under the obstruction of the gas, a uniform, flat material layer is formed and spread evenly on the surface of the chain grate 31. The hot smoke conveying fan 22 draws the hot smoke from the exhaust pipe 41 and transports it to the hot smoke distribution chamber 202 through the hot smoke pipe 21. After entering the hot smoke distribution chamber 202, the hot smoke moves upward, passes through the chain grate 31, exchanges heat with the fuel on the grate surface, and removes the moisture in the fuel. At this time, the hot smoke becomes low-temperature exhaust gas and continues to move upward, flows out of the drying heat exchange chamber 201, and finally flows back into the exhaust pipe 41 through the exhaust gas pipe 23, and is discharged to the outside by the exhaust fan 42. The fuel dried by the hot smoke continues to move backward with the chain grate 31 and enters the furnace 301 for combustion and heat release. The hot smoke generated by combustion enters the exhaust pipe 41.

[0037] During fuel combustion, if the pressure of steam produced by the boiler body 3 is less than the set value, the control system controls the adjustment mechanism to start, driving the baffle gate 6 to rise, increasing the gap between the baffle gate 6 and the chain grate 31, and increasing the fuel feed rate. At the same time, the control system calculates the net amount of moisture carried by the exhaust gas based on the exhaust gas temperature detected by the temperature detector 25 (a wet and dry bulb thermometer is used in this embodiment), and adjusts the opening size of the flow regulating valve 26 accordingly, thereby adjusting the amount of hot smoke entering the hot smoke distribution chamber 202 to ensure the drying effect.

[0038] The foregoing general description of the invention and its specific embodiments should not be construed as a limitation on the technical solution of the invention. Those skilled in the art, based on the disclosure of this application, can add, reduce, or combine the disclosed technical features in the foregoing general description and / or specific embodiments (including examples) without departing from the constituent elements of the invention, to form other technical solutions within the scope of protection of this application.

Claims

1. An integrated biomass boiler fuel feeding and drying system, characterized in that: The system includes a feeding device (1), a drying device (2), a boiler body (3), and a flue gas device (4) arranged sequentially. The flue gas device (4) includes a flue gas pipe (41) and a blower (42). The feeding device (1) includes a stacking bin (11). A feed inlet (12) is provided above the stacking bin (11), and a feed distributor (13) is provided inside the feed inlet (12). The boiler body (3) has a furnace (301) inside, and a chain grate (31) is provided at the bottom of the furnace (301). The chain grate (31) is connected to a drive device (5) and can move under the drive of the drive device (5). The front end of the chain grate (31) extends forward to the bottom of the stacking bin (11) and dries the material. The device (2) is divided into a drying heat exchange chamber (201) and a hot flue gas distribution chamber (202); the stockpile (11), the drying heat exchange chamber (201) and the furnace (301) are interconnected; the hot flue gas distribution chamber (202) is connected to the exhaust pipe (41) through the hot flue gas pipe (21); the hot flue gas pipe (21) is equipped with a hot flue gas conveying fan (22) for drawing the flue gas containing waste heat in the exhaust pipe (41) to the hot flue gas distribution chamber (202); the drying heat exchange chamber (201) is connected to the exhaust pipe (41) through the exhaust gas pipe (23); the connection position of the hot flue gas pipe (21) and the exhaust pipe (41) is located in front of the connection position of the exhaust gas pipe (23) and the exhaust pipe (41).

2. The integrated biomass boiler fuel feeding and drying system according to claim 1, characterized in that: A baffle gate (6) is provided between the material storage silo (11) and the drying heat exchange chamber (201). An adjustment mechanism is provided on the baffle gate (6). The adjustment mechanism is electrically connected to the control system and is used to drive the baffle gate (6) to move up and down to adjust the gap between the baffle gate (6) and the chain grate (31).

3. The integrated biomass boiler fuel feeding and drying system according to claim 2, characterized in that: The stockpile (11) is equipped with a level detector (14) to detect the amount of fuel entering the stockpile (11) and keep the level within a set position.

4. The integrated biomass boiler fuel feeding and drying system according to claim 1, characterized in that: The top of the drying heat exchange chamber (201) is provided with a fume hood (24), which is trapezoidal in shape with a smaller top and a larger bottom, and the outlet of the fume hood (24) is connected to the exhaust gas pipe (23).

5. The integrated biomass boiler fuel feeding and drying system according to claim 4, characterized in that: A temperature detector (25) is provided at the outlet of the fume hood (24), and a flow regulating valve (26) is provided at the outlet of the hot smoke duct (21); the temperature detector (25) and the flow regulating valve (26) are electrically connected to the control system respectively.

6. The integrated biomass boiler fuel feeding and drying system according to claim 5, characterized in that: The smoke hood (24) is equipped with a filter screen (27) at its outlet.

7. The integrated biomass boiler fuel feeding and drying system according to claim 1, characterized in that: A water-cooled fire baffle (7) is provided between the drying heat exchange chamber (201) and the furnace (301).

8. The integrated biomass boiler fuel feeding and drying system according to claim 1, characterized in that: The fabric feeder (13) is conical.

9. The integrated biomass boiler fuel feeding and drying system according to claim 3, characterized in that: The control method is as follows: First, based on the moisture content of the biomass fuel, the control system adjusts the gap between the baffle gate (6) and the chain grate (31) by controlling the regulating mechanism, and sets the operating speed of the chain grate (31); When the boiler body (3) is running, the control system controls the distributor (13), hot flue gas conveying fan (22), exhaust fan (42) and drive device (5) to start synchronously. After the high-moisture biomass fuel is transported to the top of the stacking silo (11), it enters the feed inlet (12) and falls evenly into the stacking silo (11) under the action of the distributor (13). During this process, the material level detector (14) detects the amount of fuel entering the stacking silo (11) in real time to keep the material level within the set position. The drive device (5) drives the chain grate (31) to move evenly from front to back, driving the fuel in the stacking silo (11) to move backward and pass through the baffle door (6) into the drying heat exchange chamber (201). Under the obstruction of the baffle door (6), the fuel will form a uniformly spread material layer. The hot smoke is spread out on the surface of the chain grate (31); the hot smoke conveying fan (22) draws the hot smoke from the exhaust pipe (41) and transports it to the hot smoke distribution chamber (202) through the hot smoke pipe (21); after entering the hot smoke distribution chamber (202), the hot smoke moves upward, passes through the chain grate (31), exchanges heat with the fuel on the surface of the grate, and takes away the moisture in the fuel; at this time, the hot smoke will become low-temperature exhaust gas and continue to move upward, flow out of the drying heat exchange chamber (201), and finally flow back into the exhaust pipe (41) through the exhaust gas pipe (23), and is discharged to the outside by the exhaust fan (42); while the fuel dried by the hot smoke continues to move backward with the chain grate (31) and enters the furnace (301) for combustion and heat release, and the hot smoke generated by combustion enters the exhaust pipe (41); During fuel combustion, if the pressure of steam produced by the boiler body (3) is less than the set value, the control system will start the regulating mechanism to drive the baffle gate (6) to rise, increase the gap between the baffle gate (6) and the chain grate (31), and increase the fuel feed.

10. The integrated biomass boiler fuel feeding and drying system according to claim 9, characterized in that: A temperature detector (25) is provided at the outlet of the drying heat exchange chamber (201), and a flow regulating valve (26) is provided at the outlet of the hot flue pipe (21). The temperature detector (25) and the flow regulating valve (26) are electrically connected to the control system. During the fuel combustion process, the control system calculates the net amount of moisture carried by the exhaust gas based on the exhaust gas temperature detected by the temperature detector (25) at the outlet of the drying heat exchange chamber (201), and adjusts the opening size of the flow regulating valve (26) accordingly.

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