Integrated biomass boiler fuel feeding and drying system and control method thereof

Abstract

The invention provides an integral biomass boiler fuel feeding and drying system and a control method thereof. According to the drying system, a feeding device, a drying device, a boiler body and a smoke exhaust device are integrated together, a chain grate stoker of the boiler body extends forwards all the time into the drying device and the feeding device, fuel feeding, drying and combustion are conducted synchronously in the working process, 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

Technical Field

[0001] The present invention relates to the technical field of biomass boilers, and in particular to an integrated biomass boiler fuel feeding drying system and a control method thereof. Background Art

[0002] The biomass chain boiler is a layer-fired boiler that uses biomass fuel as its core energy source. Its specific structural design gives it unique advantages in combustion control, fuel adaptability, and environmental performance: (1) The chain grate mainly adopts layered combustion, and the fuel forms a stable combustion layer on the grate. At the same time, the lighter volatile matter and fine particles are suspended and burned in the furnace; this mixed combustion mode prolongs the fuel residence time, ensuring that the volatile matter (accounting for about 70-80% of the calorific value of the biomass) 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 is precisely controlled: the primary air is sent in from the bottom of the grate to support the layer combustion; the secondary air is injected at high speed from the top of the furnace to enhance the air flow disturbance, promote the mixing of volatile matter and air, and inhibit the generation of nitrogen oxides. (3) A PLC control system is used to automatically adjust the grate movement speed, air supply volume, and feed amount according to the fuel status and load demand. (4) It can adapt to a variety of biomass fuels, including agricultural waste (straw, rice husks, corn cobs, etc.), forestry residues (wood chips, bark, branches, etc.), processing by-products (bagasse, fruit shells, hemp stalks, etc.), and molded fuels (granular or briquette biomass, moisture ≤40%). (5) It has good tolerance to fuel characteristics: through the preheating and drying area at the front end of the furnace and the ultra-large combustion chamber design, it can handle fuels with a moisture content of up to 40-50%; it supports the co-combustion of biomass of different types and forms, such as mixing bark and straw; it is suitable for bulk materials or molded particles with a particle size of ≤50mm, and can avoid the leakage of fine fuel (which needs to be pressed into particles). At present, biomass chain boilers have become the preferred solution in the field of small and medium-sized heating due to their wide fuel adaptability, significant environmental benefits and high degree of automation. They are widely used in agricultural processing parks, district heating and other scenarios. With the upgrade of combustion control technology (such as AI optimized air distribution) and pollutant co-treatment systems (such as SNCR denitrification), its penetration rate in the large industrial boiler market is expected to further increase in the future.

[0003] In practice, technicians have adopted a design with a preheating and drying zone and an extra-large combustion chamber at the front of the furnace to burn biomass fuels with moisture contents as high as 40-50%. While this design has achieved some success, it still suffers from the following drawbacks: 1) Low combustion efficiency: High-moisture biomass fuels have a low calorific value, and the evaporation of moisture consumes a large amount of heat, resulting in reduced combustion efficiency and significantly increasing fuel costs for users. 2) Risk of grate vibration and deflagration: High moisture content in fuel can cause increased grate vibration and even lead to furnace deflagration, threatening safe boiler operation. 3) Flue gas disturbance and high ash carbon content: Fuels with high moisture content generate large amounts of water vapor during combustion, disrupting flue gas flow and increasing the carbon content of ash, further reducing boiler efficiency. 4) Incomplete combustion: Fuels with high evaporative content release large amounts of water vapor during combustion, lowering combustion temperatures, affecting combustion completeness, leading to heat loss and increased emissions. 5) Poor combustion stability: Fuels with high evaporative content are prone to combustion instability, potentially resulting in flame extinction and uneven combustion, which can affect boiler load stability. In summary, using chain grates to burn high-moisture biomass fuels presents a range of challenges, including low combustion efficiency, increased safety risks, increased environmental pollution, and poor operational stability. These issues not only impact the normal operation and thermal efficiency of the boiler but also pose additional safety risks and financial burdens. Therefore, practical applications require the implementation of appropriate technical measures and management strategies to address these challenges. Summary of the Invention

[0004] The present invention provides an integrated biomass boiler fuel feeding and drying system for solving the above-mentioned problems existing in the prior art. The integrated biomass boiler fuel feeding and drying system of the present invention is suitable for high-moisture biomass fuel. The system integrates a feeding device, a drying device, a boiler body, and a smoke exhaust device, saving layout space and having low construction cost. In addition, the chain grate of the boiler body extends forward into the drying device and the feeding device, so that fuel supply, drying, and combustion are carried out simultaneously during operation. The fuel is directly sent to the furnace for combustion after entering the site and drying, saving fuel storage space, reducing fuel storage risks, and being more convenient to control. In addition, the drying device is divided into a drying heat exchange chamber and a hot smoke distribution chamber by the chain grate, and each is connected to the smoke exhaust duct, so that the waste heat of the flue gas discharged from the boiler body can be used to remove moisture in the fuel and then discharged into the smoke exhaust duct at the rear, thereby preventing moisture in the fuel from entering the furnace and participating in combustion, thereby improving combustion efficiency. In addition, the waste heat of the flue gas is used to dry the high-moisture fuel, which is beneficial to improving energy utilization, while reducing the exhaust temperature and reducing environmental pollution. Correspondingly, the present invention also provides a control method for the aforementioned integrated biomass boiler fuel feed drying system.

[0005] For the drying system, the technical solution of the present invention is:

[0006] The integrated biomass boiler fuel feeding and drying system comprises a feeding device, a drying device, a boiler body and a smoke exhaust device which are arranged in sequence; the smoke exhaust device comprises a smoke exhaust pipe and an exhaust fan; the feeding device comprises a stacking bin, a feeding port is provided above the stacking bin, and a distributor is provided in the feeding port; a furnace is provided inside the boiler body, and a chain grate is provided at the bottom of the furnace; the chain grate is connected to a driving device and can be moved under the drive of the driving device, and the front end of the chain grate extends forward to the interior of the stacking bin and divides the drying device into a drying heat exchange chamber and a hot smoke distribution chamber; the stacking bin, the drying heat exchange chamber and the furnace are connected to each other; the hot smoke distribution chamber is connected to the smoke exhaust pipe through a hot smoke pipe; a hot smoke conveying fan is provided on the hot smoke pipe for extracting the smoke containing waste heat in the smoke exhaust pipe into the hot smoke distribution chamber; the drying heat exchange chamber is connected to the smoke exhaust pipe through an exhaust gas pipe; the connection position of the hot smoke pipe and the smoke exhaust pipe is located in front of the connection position of the exhaust gas pipe and the smoke exhaust pipe.

[0007] Compared with the prior art, the integrated biomass boiler fuel feeding and drying system of the present invention is suitable for high-moisture biomass fuel; the system integrates the feeding device, drying device, boiler body and smoke exhaust device together, and the chain grate of the boiler body extends forward into the drying device and feeding device, so that the fuel supply, drying and combustion are carried out simultaneously during operation, and the control is relatively convenient. Moreover, the fuel is directly sent to the furnace for combustion after entering the site and drying, which saves the space occupied by fuel stacking and reduces the storage risk of fuel; in addition, the drying device is divided into a drying heat exchange chamber and a hot smoke distribution chamber by the chain grate, and is connected to the smoke exhaust pipe respectively, so that the waste heat-containing flue gas discharged from the boiler body can be used to take away the moisture in the fuel, and then discharged to the smoke exhaust pipe at the tail, thereby avoiding the moisture in the fuel from entering the furnace to participate in combustion, thereby improving the combustion efficiency, and using the waste heat of the flue gas to dry the high-moisture fuel is beneficial to improving energy utilization, while reducing the exhaust temperature and reducing pollution to the environment.

[0008] As an optimization, the aforementioned integrated biomass boiler fuel feeding and drying system features a retaining door between the stockpile and the drying and heat exchange chamber. This door is equipped with an adjustment mechanism, which is electrically connected to the control system and drives the retaining door up and down to adjust the gap between it and the chain grate. This allows the gap between the retaining door and the chain grate to be automatically adjusted based on the moisture content of the biomass fuel before combustion and the pressure of the steam produced by the boiler during combustion, ensuring the proper fuel feeding.

[0009] Furthermore, the bunker is equipped with a material level detector to monitor the amount of material entering the bunker and maintain the material level within the set position. This stable material level provides stable static pressure for the fuel to flow smoothly and evenly through the mechanical material blocking door into the chain grate inside the boiler body. It also ensures that the inflow and outflow of material is balanced with the combustion consumption of the boiler body.

[0010] As an optimization, the aforementioned integrated biomass boiler fuel feed drying system features a trapezoidal hood installed on top of the drying and heat exchange chamber. The hood's outlet is connected to the exhaust gas duct. This allows the exhaust gas entering the hood to be more quickly directed to the exhaust gas duct, reducing its residence time within the hood and improving exhaust efficiency.

[0011] Furthermore, a temperature detector is installed at the smoke hood outlet, and a corresponding flow control valve is installed at the outlet of the hot smoke duct. The temperature detector and flow control valve are each electrically connected to a control system. After the hot smoke dries the fuel, it removes moisture from the fuel, turning it into exhaust gas, which is saturated with steam. By measuring the exhaust gas temperature at the smoke hood outlet, the net amount of moisture carried by the exhaust gas can be calculated, thereby determining the moisture content in the fuel. The flow control valve opening can then be adjusted based on the moisture content to adjust the amount of hot smoke entering the hot smoke distribution chamber and ensure the drying effect.

[0012] Furthermore, a filter is provided at the outlet of the smoke hood, thereby filtering out impurities in the exhaust gas and then discharging it outdoors, thereby further reducing pollution to the environment.

[0013] As an optimization, in the aforementioned integrated biomass boiler fuel feed drying system, a water-cooled fire damper is installed between the drying and heat exchange chamber and the furnace. This water-cooled fire damper serves to shield the flames in the furnace from radiating onto the biomass fuel in the drying and heat exchange chamber, thereby increasing the operational reliability of the drying system.

[0014] As an optimization, the distributor in the aforementioned integrated biomass boiler fuel feeding and drying system is conical in shape. This conical structure naturally guides fuel from the center to the periphery, preventing accumulation in a single area. This ensures uniform loading across the combustion section within the furnace and reduces localized high temperatures or unburned fuel. Furthermore, the cone's inclination angle is typically ≥60°, allowing for gravity flow and reducing fuel adhesion or retention, making it suitable for distributing high-moisture biomass fuel.

[0015] Correspondingly, the present application also provides a control method for the aforementioned integrated biomass boiler fuel feeding and drying system. First, according to the moisture content of the biomass fuel, the control system controls the regulating mechanism to adjust the gap between the material retaining door and the chain grate, and sets the operating speed of the chain grate; when the boiler body is running, the control system controls the distributor, hot smoke conveying fan, exhaust fan and driving device to start synchronously; after the high-moisture biomass fuel is transported to the top of the stockpile bin, it enters the feed inlet and falls evenly into the stockpile bin under the action of the distributor. During this process, the material level detector detects the amount of fuel entering the stockpile bin in real time, so that the material level is maintained within the set position, ensuring the balance between the feed amount and the combustion consumption of the boiler body; the driving device drives the chain grate to move evenly from front to back, driving the fuel in the stockpile bin to move backward and pass through the material retaining door into the drying heat exchange chamber. Under the obstruction of the material retaining door, the fuel will form a uniform flat material layer, which is spread evenly on the discharge surface of the chain grate; the hot smoke conveying fan extracts the fuel in the exhaust pipe The hot smoke is transported to the hot smoke distribution room through the hot smoke pipe; after entering the hot smoke distribution room, the hot smoke moves upward, passes through the chain grate, exchanges heat with the fuel on the grate surface, 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, and finally flow back to the exhaust pipe through the exhaust pipe, and be discharged to the outside by the exhaust fan; and the fuel dried by the hot smoke continues to move backward with the chain grate, enters the furnace for combustion and heat release, and the hot smoke generated by the combustion enters the exhaust pipe; during the fuel combustion process, if it is detected that the pressure of the steam produced by the boiler body is less than the set value, the control system controls the adjustment mechanism to start, drive the material blocking door to rise, increase the gap between the material blocking door and the chain grate, and increase the fuel feed amount; at the same time, the control system converts the net amount of moisture carried by the exhaust gas according to 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 control valve to adjust the amount of hot smoke entering the hot smoke distribution room to ensure the drying effect.

[0016] When the dry flue gas flows from the hot flue gas duct into the hot flue gas distribution chamber and then flows out from the drying heat exchange chamber to the exhaust gas duct, a slight positive pressure will be formed in the drying heat exchange chamber, thereby preventing the flame in the furnace from backfiring and burning back into the drying heat exchange chamber.

[0017] The control method of the integrated biomass boiler fuel feeding and drying system of the present application controls the distributor, hot smoke conveying fan, exhaust fan and driving device to start synchronously, so that fuel supply, drying and combustion can be carried out synchronously, and each link does not need to be logically controlled by itself, and the operation is convenient and easy to implement; at the same time, during the fuel combustion process, the gap between the material blocking door and the chain grate is adjusted according to the detected pressure of the steam produced by the boiler body, and the net amount of moisture carried by the exhaust gas is converted according to the detected exhaust gas temperature at the outlet of the drying heat exchange chamber, and the amount of hot smoke entering the hot smoke distribution chamber is adjusted, thereby ensuring the drying effect of the fuel and improving the combustion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of the integrated biomass boiler fuel feed drying system of the present application;

[0019] Figure 2 This is a schematic diagram of the integrated biomass boiler fuel feed drying system of the present application.

[0020] The marks in the accompanying drawings are: 1-feeding device, 11-stock bin, 12-feeding port, 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-smoke hood, 25-temperature detector, 26-flow regulating valve, 27-filter; 3-boiler body, 301-furnace, 31-chain grate, 311-grate combustion zone, 312-grate burning zone; 4-smoke exhaust device, 41-smoke exhaust duct, 42-exhaust fan; 5-driving device; 6-material blocking door; 7-water-cooled fire blocking door. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings, but is not intended to limit the present invention. The contents not described in detail in the following embodiments are all common technical knowledge in the art.

[0022] See also Figure 1 and Figure 2 ( Figure 1In order to show the internal structure of the device, part of the shell is removed). 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 smoke exhaust device 4 arranged in sequence; the smoke exhaust device 4 includes a smoke exhaust pipe 41 and an exhaust fan 42; the feeding device 1 includes a stacking bin 11; a feed port 12 is provided above the stacking bin 11, and a distributor 13 is provided in the feed port 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 the driving device 5 and can be moved under the drive of the driving device 5, and the front end of the chain grate 31 It extends forward to the bottom of the stacking bin 11 and divides the drying device 2 into a drying heat exchange chamber 201 and a hot smoke distribution chamber 202; the stacking bin 11, the drying heat exchange chamber 201 and the furnace 301 are interconnected; the hot smoke distribution chamber 202 is connected to the smoke exhaust duct 41 through a hot smoke duct 21; a hot smoke conveying fan 22 is provided on the hot smoke duct 21, which is used to pump the smoke containing waste heat in the smoke exhaust duct 41 into the hot smoke distribution chamber 202; the drying heat exchange chamber 201 is connected to the smoke exhaust duct 41 through an exhaust gas duct 23; the connection position of the hot smoke duct 21 and the smoke exhaust duct 41 is located in front of the connection position of the exhaust gas duct 23 and the smoke exhaust duct 41.

[0023] The integrated biomass boiler fuel feeding and drying system of the present invention systematically integrates the boiler body 3 (including the chain grate and the matching furnace arch, secondary air, etc.) with the feeding device 1. On the one hand, it fully utilizes the power, control system, and feeding and distribution functions of the original boiler body. On the other hand, by arranging the 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, the fuel supply, drying, and combustion are carried out simultaneously during operation, which saves the space occupied by the fuel stacking and reduces the storage risk of the fuel. Moreover, the drying device 2 is divided into a drying heat exchange chamber 201 and a hot smoke distribution chamber 201 by the chain grate 31. 02, and are respectively connected to the smoke exhaust pipe 41, so that the smoke with waste heat discharged from the boiler body 3 can be used to take away the moisture in the fuel, and then discharged to the smoke exhaust pipe 41 at the tail, avoiding the moisture in the fuel from 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 plays the advantages of the chain biomass combustion boiler: high efficiency, environmental protection, strong fuel adaptability, easy operation and high degree of automation, and solves a series of problems existing in the prior art of chain grate burning high-moisture biomass fuel, such as low combustion efficiency, increased safety hazards, aggravated environmental pollution and poor operation stability.

[0024] In the prior art, the chain grate area in the furnace 301 of the boiler body used for high-moisture biomass fuel can be divided into a grate combustion zone 311 and a grate burnout zone 312, and the grate burnout zone 312 usually accounts for more than 50% of the total grate length; in the present invention, after the high-moisture biomass fuel is dried using the drying device 2, the moisture carried by the fuel is greatly reduced, thereby improving its combustion efficiency in the boiler body 3 (the combustion efficiency can be improved by more than 3%). Therefore, the length of the grate burnout zone 312 of the boiler body 3 in the present invention can be reduced by about 50% (that is, the grate 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 volume in the grate burnout zone 312 can be reduced by about 30%, thereby optimizing the amount of air used for combustion.

[0025] Example:

[0026] In this embodiment, a material blocking door 6 is provided between the storage bin 11 and the drying and heat exchange chamber 201. This door 6 is equipped with an adjustment mechanism, which is electrically connected to a control system and is used to drive the door 6 up and down to adjust the gap between the door 6 and the chain grate 31. This allows the gap between the door 6 and the chain grate 31 to be automatically adjusted based on the moisture content of the biomass fuel before combustion and the pressure of the steam produced by the boiler body 3 during combustion, thereby ensuring the proper fuel supply.

[0027] Furthermore, the bunker 11 is equipped with a material level detector 14 for detecting the amount of fuel entering the bunker 11 and maintaining the material level within a set position. This stable material level ensures that the fuel is smoothly and evenly spread through the mechanical material blocking door and enters the chain grate 31 in the boiler body 3, providing a stable static pressure and ensuring a balance between the feed volume and the combustion consumption of the boiler body 3.

[0028] In this embodiment, a smoke hood 24 is installed on the top of the drying and heat exchange chamber 201. The smoke hood 24 is in a trapezoidal shape, smaller at the top and larger at the bottom. The outlet of the smoke hood 24 is connected to the exhaust gas duct 23. As a result, the exhaust gas entering the smoke hood 24 can be guided to the exhaust gas duct 23 more quickly, reducing the residence time of the exhaust gas inside the smoke hood 24 and thus improving the exhaust efficiency.

[0029] Furthermore, a temperature detector 25 is provided at the outlet of the smoke hood 24, and a corresponding flow control valve 26 is provided at the outlet of the hot smoke duct 21. Both the temperature detector 25 and the flow control valve 26 are electrically connected to the control system. After the hot smoke dries the fuel, it removes moisture from the fuel, turning it into exhaust gas, which is saturated with steam. By measuring the exhaust gas temperature at the outlet of the smoke hood 24, the net amount of moisture carried by the exhaust gas can be calculated. The opening size of the flow control valve 26 can then be adjusted based on the moisture content to adjust the amount of hot smoke entering the hot smoke distribution chamber 202 and ensure the drying effect.

[0030] Furthermore, a filter 27 is provided at the outlet of the smoke hood 24. Thus, impurities in the exhaust gas can be filtered out by the filter 27 and then discharged outdoors, thereby further reducing pollution to the environment.

[0031] In this embodiment, a water-cooled fire-blocking door 7 is provided between the drying heat exchange chamber 201 and the furnace 301 to shield the flame in the furnace 301 from radiating to the fuel in the drying heat exchange chamber 201, thereby increasing the operational reliability of the drying system of the present invention.

[0032] In this embodiment, the distributor 13 is conical. This conical structure naturally guides the fuel from the center to the surrounding area, preventing accumulation in a single area, ensuring uniform loading across the combustion section within the furnace, and reducing localized high temperatures or unburned fuel. Furthermore, the cone's inclination angle is typically ≥60°, allowing for gravity flow and reducing fuel adhesion or retention, making it suitable for distributing fuel to high-moisture biomass fuels.

[0033] The control method of the integrated biomass boiler fuel feed drying system in this embodiment is as follows.

[0034] First, according to the moisture content of the high-moisture biomass fuel, the control system controls the regulating mechanism to adjust the gap between the material blocking door 6 and the chain grate 31, and sets the operating speed of the chain grate 31 (for example, when the moisture content is high, the gap between the material blocking door 6 and the chain grate 31 is reduced. At this time, the material layer thickness is low and the drying resistance is small. At the same time, the operating speed of the chain grate 31 is increased to ensure the feeding amount).

[0035] When the boiler body 3 is running, the control system controls the distributor 13, the hot smoke conveying fan 22, the exhaust fan 42 and the driving device 5 to start synchronously; the high-moisture biomass fuel is conveyed (by a separately equipped feeding device) to the top of 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 material level detector 14 detects the amount of fuel entering the stockpile 11 in real time, so that the material level is maintained within the set position, ensuring the balance between the feed amount and the combustion consumption of the boiler body 3; the driving device 5 drives the chain grate 31 to move evenly from front to back, driving the fuel in the stockpile 11 to move backward, and pass through the material blocking door 6 into the drying heat exchange chamber 201. The fuel is at the material blocking door 6. Under the obstruction of , a uniform flat material layer will be formed and spread flat on the discharge surface of the chain grate 31; the hot smoke conveying fan 22 extracts the hot smoke in 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 discharge surface, 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 to the exhaust pipe 41 through the exhaust gas pipe 23, and be discharged to the outside by the exhaust fan 42; and the fuel dried by the hot smoke continues to move backward with the chain grate 31, enters the furnace 301 to burn and release heat, and the hot smoke generated by the combustion enters the exhaust pipe 41.

[0036] During the fuel combustion process, if it is detected that the pressure of the steam produced by the boiler body 3 is less than the set value, the control system controls the regulating mechanism to start, driving the material blocking door 6 to rise, increasing the gap between the material blocking door 6 and the chain grate 31, and increasing the fuel feed rate; at the same time, the control system converts the exhaust gas temperature at the outlet of the smoke hood 24 detected by the temperature detector 25 (a dry-bulb thermometer is used in this embodiment) into the net amount of moisture carried by the exhaust gas, 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.

[0037] The above general description of the invention and the description of its specific embodiments involved in this application should not be construed as limiting the technical solutions of the invention. Based on the disclosure of this application, those skilled in the art may, without violating the constituent elements of the invention involved, add to, subtract from, or combine the disclosed technical features in the above general description and / or specific embodiments (including examples) to form other technical solutions within the scope of protection of this application.

Claims

1. The integrated biomass boiler fuel feed drying system is characterized by: The invention comprises a feeding device (1), a drying device (2), a boiler body (3) and a smoke exhaust device (4) which are arranged in sequence; the smoke exhaust device (4) comprises a smoke exhaust pipe (41) and an exhaust fan (42); the feeding device (1) comprises a stacking bin (11); a feeding port (12) is provided above the stacking bin (11), and a distributor (13) is provided inside the feeding port (12); a furnace (301) is provided inside the boiler body (3), and a chain grate (31) is provided at the bottom of the furnace (301); the chain grate (31) is connected to a driving device (5) and can be moved under the drive of the driving device (5), and the front end of the chain grate (31) extends forward to the bottom of the stacking bin (11), and the drying The device (2) is divided into a drying heat exchange chamber (201) and a hot smoke distribution chamber (202); the stacking bin (11), the drying heat exchange chamber (201) and the furnace (301) are interconnected; the hot smoke distribution chamber (202) is connected to the smoke exhaust pipe (41) through a hot smoke pipe (21); a hot smoke conveying fan (22) is provided on the hot smoke pipe (21) for pumping the smoke containing waste heat in the smoke exhaust pipe (41) into the hot smoke distribution chamber (202); the drying heat exchange chamber (201) is connected to the smoke exhaust pipe (41) through an exhaust gas pipe (23); the connection position of the hot smoke pipe (21) and the smoke exhaust pipe (41) is located in front of the connection position of the exhaust gas pipe (23) and the smoke exhaust pipe (41).

2. The integrated biomass boiler fuel feed drying system according to claim 1 is characterized in that: A material blocking door (6) is provided between the material stacking bin (11) and the drying heat exchange chamber (201), and an adjustment mechanism is provided on the material blocking door (6); the adjustment mechanism is electrically connected to the control system and is used to drive the material blocking door (6) to move up and down to adjust the gap between the material blocking door (6) and the chain grate (31).

3. The integrated biomass boiler fuel feed drying system according to claim 2, characterized in that: The stacking bin (11) is provided with a material level detector (14) for detecting the amount of fuel entering the stacking bin (11) so as to maintain the material level within a set position.

4. The integrated biomass boiler fuel feed drying system according to claim 1, characterized in that: A smoke hood (24) is provided on the top of the drying heat exchange chamber (201). The smoke hood (24) is in a trapezoidal shape with a small top and a large bottom, and an outlet of the smoke hood (24) is connected to the exhaust gas pipeline (23).

5. The integrated biomass boiler fuel feed drying system according to claim 4, characterized in that: A temperature detector (25) is provided at the outlet of the smoke hood (24), and correspondingly, 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 respectively electrically connected to a control system.

6. The integrated biomass boiler fuel feed drying system according to claim 5, characterized in that: A filter screen (27) is provided at the outlet of the smoke hood (24).

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

8. The integrated biomass boiler fuel feed drying system according to claim 1, characterized in that: The distributor (13) is conical.

9. The control method of the integrated biomass boiler fuel feed drying system according to claim 3, characterized in that: First, according to the moisture content of the biomass fuel, the control system controls the regulating mechanism to adjust the gap between the material blocking door (6) and the chain grate (31), and sets the operating speed of the chain grate (31); When the boiler body (3) is in operation, the control system controls the distributor (13), the hot smoke conveying fan (22), the exhaust fan (42) and the driving device (5) to start synchronously; after being transported to the top of the stock bin (11), the high-moisture biomass fuel enters the feed inlet (12) and falls evenly into the stock bin (11) under the action of the distributor (13). During this process, the material level detector (14) detects the amount of fuel entering the stock bin (11) in real time to maintain the material level within the set position; the driving device (5) drives the chain grate (31) to move evenly from front to back, driving the fuel in the stock bin (11) to move backward and pass through the blocking door (6) into the drying heat exchange chamber (201). The fuel will form a uniform flat material layer under the blocking of the blocking door (6). , spread out on the row surface of the chain grate (31); the hot smoke conveying fan (22) extracts the hot smoke in 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 row surface, 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 to the exhaust pipe (41) through the exhaust pipe (23), and is discharged to the outside by the exhaust fan (42); and the fuel dried by the hot smoke continues to move backward along the chain grate (31), enters the furnace (301) to burn and release heat, and the hot smoke generated by the combustion enters the exhaust pipe (41); During the fuel combustion process, if it is detected that the pressure of the steam produced by the boiler body (3) is less than the set value, the control system controls the regulating mechanism to start, driving the material blocking door (6) to rise, increasing the gap between the material blocking door (6) and the chain grate (31), and increasing the fuel feeding amount.

10. The control method of the integrated biomass boiler fuel feed 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 correspondingly, a flow regulating valve (26) is provided at the outlet of the hot smoke pipe (21); the temperature detector (25) and the flow regulating valve (26) are respectively electrically connected to a 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 at the outlet of the drying heat exchange chamber (201) detected by the temperature detector (25), and adjusts the opening size of the flow regulating valve (26) accordingly.

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