Integral biomass boiler fuel feeding drying system and control method thereof

Abstract

The present application provides a whole biomass boiler fuel feeding drying system and a control method thereof; wherein the drying system integrates the feeding device, the drying device, the boiler body and the smoke exhaust device together, and the chain grate of the boiler body extends forward to the drying device and the feeding device, so that the fuel feeding, drying and combustion are synchronized during work, the fuel stacking ground space is saved, and the fuel storage risk is reduced; in addition, the drying device is separated into a drying heat exchange chamber and a hot smoke distribution chamber by the chain grate, and is respectively connected with the smoke exhaust pipeline, so that the moisture in the fuel can be taken away by the flue gas with waste heat discharged by the boiler body, and then discharged to the tail smoke exhaust pipeline, thereby avoiding the moisture in the fuel entering the furnace to participate in combustion, improving the combustion efficiency, and utilizing the waste heat of the flue gas to dry the high-moisture biomass fuel, which is beneficial to improve the energy utilization rate, and at the same time, the exhaust gas temperature is reduced, and the pollution to the environment is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biomass boiler, in particular to a whole biomass boiler fuel feeding and drying system and a control method thereof. BACKGROUND

[0002] The biomass chain boiler is a layer combustion boiler taking biomass fuel as the core energy, and the 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, and the lighter volatile matter and fine particles are suspended and burned in the furnace; this mixed combustion mode prolongs the fuel residence time, ensures the full combustion of volatile matter (about 70-80% of the heat value of biomass), 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 accurately controlled: the primary air is sent from the bottom of the grate to support the layer combustion; the secondary air is injected from the upper part of the furnace at high speed to enhance the airflow disturbance and promote the mixing of volatile matter and air, and to inhibit the generation of nitrogen oxides; (3) A PLC control system is adopted to automatically adjust the grate moving speed, air supply amount and fuel feeding amount 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 ≤40%); (5) Good adaptability to fuel characteristics: through the preheating and drying area at the front end of the furnace and the design of the super-large combustion chamber, fuels with moisture up to 40-50% can be processed; it supports the co-combustion of different types and forms of biomass, such as mixed combustion of bark and straw; it is suitable for bulk materials or shaped particles with a particle size of ≤50mm, which can avoid the leakage of fine fuels (which need to be pressed into particles). At present, the biomass chain boiler has become the preferred solution in the small and medium-sized heating field due to its wide fuel adaptability, significant environmental protection benefits and high automation level, and is widely used in agricultural processing parks, regional heating and other scenes. With the upgrading of combustion control technology (such as AI optimized air distribution) and pollution co-processing system (such as SNCR denitrification), the penetration rate of the biomass chain boiler in the large industrial boiler market is expected to further increase in the future.

[0003] In practical applications, technicians use the design of setting up a preheating drying area and an oversized combustion chamber at the front end of the furnace for burning biomass fuel with moisture content up to 40-50%, although certain effects have been achieved, but there are still the following shortcomings: 1) low combustion efficiency: the calorific value of high-moisture biomass fuel is low, and the evaporation of water consumes a large amount of heat, resulting in a decrease in combustion efficiency, greatly increasing the fuel consumption cost of users. 2) grate vibration and risk of deflagration: when the fuel moisture is high, it may cause the grate vibration to intensify, and even cause the furnace to deflagrate, threatening the safe operation of the boiler. 3) flue gas disturbance and high carbon content in ash: high-moisture fuel produces a large amount of water vapor during the combustion process, which disturbs the flue gas flow and increases the carbon content in ash, further reducing the efficiency of the boiler. 4) incomplete combustion: high-moisture fuel releases a large amount of water vapor during the combustion process, which lowers the combustion temperature and affects the completeness of combustion, resulting in heat loss and increased emissions. 5) poor combustion stability: high-moisture fuel is prone to cause instability in the combustion process, which may cause flame extinction, uneven combustion, and other problems, affecting the stability of the boiler load. In summary, using chain grate combustion to burn high-moisture biomass fuel will encounter a series of problems such as low combustion efficiency, increased safety hazards, increased environmental pollution, and poor operation stability. These problems not only affect the normal operation and thermal efficiency of the boiler, but also may cause additional safety risks and economic burdens. Therefore, in practical applications, appropriate technical measures and management strategies need to be taken to address these challenges. SUMMARY

[0004] The present application provides a whole biomass boiler fuel feeding and drying system to solve the above-mentioned problems in the prior art. The whole biomass boiler fuel feeding and drying system of the present application is suitable for high-moisture biomass fuel. The system integrates the feeding device, drying device, boiler body, and exhaust gas device together, saving space and reducing cost. The chain grate of the boiler body extends forward into the drying device and the feeding device, so that the fuel feeding, drying, and combustion are synchronized during operation. The dried fuel is directly sent to the furnace for combustion, saving the space occupied by fuel storage and reducing the risk of fuel storage. The control is also more convenient. In addition, the drying device is separated into a drying and heat exchange chamber and a hot smoke distribution chamber by the chain grate, and is connected to the exhaust gas pipeline, so that the water in the fuel can be carried away by the exhaust gas with waste heat from the boiler body, and then discharged into the exhaust gas pipeline at the tail, thereby avoiding the water in the fuel from entering the furnace for combustion, improving the combustion efficiency, and utilizing the waste heat of the exhaust gas to dry the high-moisture fuel, which is beneficial to improving the energy utilization rate and reducing the exhaust gas temperature and the pollution to the environment. Correspondingly, the present application also provides a control method for the whole biomass boiler fuel feeding and drying system.

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

[0006] The whole biomass boiler fuel feeding and drying system comprises a feeding device, a drying device, a boiler body and an exhaust device arranged in sequence; the exhaust device comprises an exhaust pipe and an exhaust fan; the feeding device comprises a stock bin, the upper portion of the stock bin is provided with a feeding inlet, and a distributor is arranged in the feeding inlet; the inside of the boiler body is provided with a hearth, and the bottom of the hearth is provided with a chain grate; the chain grate is connected with a driving device and can move under the driving of the driving device, and the front end of the chain grate extends to the inside of the stock bin and separates the drying device into a drying and heat exchange chamber and a hot smoke distribution chamber; the stock bin, the drying and heat exchange chamber and the hearth are communicated with each other; the hot smoke distribution chamber is communicated with the exhaust pipe through a hot smoke pipe; a hot smoke conveying fan is arranged on the hot smoke pipe and used for conveying the flue gas containing waste heat in the exhaust pipe to the hot smoke distribution chamber; the drying and heat exchange chamber is communicated with the exhaust pipe through a waste gas pipe; and the connection position of the hot smoke pipe and the exhaust pipe is located on the front side of the connection position of the waste gas pipe and the exhaust pipe.

[0007] Compared with the prior art, the whole biomass boiler fuel feeding and drying system is suitable for high-moisture biomass fuel; the feeding device, the drying device, the boiler body and the exhaust device are arranged together, and the chain grate of the boiler body extends to the drying device and the feeding device, so that fuel feeding, drying and combustion are synchronously performed during work, control is convenient, fuel is directly sent to the hearth for combustion after drying, the fuel stacking space is saved, and the fuel storage risk is reduced; in addition, the drying device is separated into the drying and heat exchange chamber and the hot smoke distribution chamber by the chain grate and is communicated with the exhaust pipe, so that the moisture in the fuel can be taken away by the flue gas containing waste heat discharged by the boiler body and then discharged to the exhaust pipe at the tail, thereby avoiding that the moisture in the fuel enters the hearth to participate in combustion, improving the combustion efficiency, drying the high-moisture fuel by using the waste heat of the flue gas, improving the energy utilization rate, reducing the exhaust temperature and reducing the pollution to the environment.

[0008] As optimization, the foregoing whole biomass boiler fuel feeding and drying system is provided with a material blocking door between the stock bin and the drying and heat exchange chamber, and an adjusting mechanism is arranged on the material blocking door; the adjusting mechanism is electrically connected with a control system and is used for driving the material blocking door to move up and down to adjust the gap between the material blocking door and the chain grate. In this way, the gap between the material blocking door and the chain grate can be automatically adjusted according to the water content of the biomass fuel before fuel combustion and according to the steam pressure generated by the boiler body during fuel combustion, so as to ensure the fuel feeding amount.

[0009] Further, the stack is provided with a material level detector for detecting the amount of material entering the stack so as to maintain the material level within a set position. The stable material level provides a stable static pressure for the fuel to be evenly laid into the chain grate of the boiler body through the mechanical material blocking door. Moreover, the feeding amount can be balanced with the consumption amount of the boiler body.

[0010] As an optimization, the top of the drying heat exchange chamber in the aforementioned integrated biomass boiler fuel feeding and drying system is provided with a smoke hood in a trapezoidal shape with a small top and a large bottom. The outlet of the smoke hood is connected with the exhaust gas pipeline. In this way, the exhaust gas can be more quickly guided to the exhaust gas pipeline after entering the smoke hood, reducing the residence time of the exhaust gas in the smoke hood, thereby improving the smoke exhaust efficiency.

[0011] Further, the outlet of the smoke hood is provided with a temperature detector, and the outlet of the hot smoke pipeline is provided with a flow regulating valve. The temperature detector and the flow regulating valve are electrically connected with the control system. After the fuel is dried by the hot smoke, the water in the fuel is taken away and becomes exhaust gas in a saturated steam state. By measuring the temperature of the exhaust gas at the outlet of the smoke hood, the net value of the water carried by the exhaust gas can be calculated, so as to know the water content in the fuel. Then, the opening size of the flow regulating valve can be adjusted according to the water content, so as to adjust the amount of hot smoke entering the hot smoke distribution chamber and ensure the drying effect.

[0012] Further, the outlet of the smoke hood is provided with a filter screen. In this way, the impurities in the exhaust gas can be filtered out through the filter screen before being discharged to the outside, thereby further reducing the pollution to the environment.

[0013] As an optimization, the water-cooled fire door is arranged between the drying heat exchange chamber and the furnace in the aforementioned integrated biomass boiler fuel feeding and drying system. The water-cooled fire door can be used to shield the flame in the furnace from radiating to the biomass fuel in the drying heat exchange chamber, thereby increasing the operation reliability of the drying system.

[0014] As an optimization, the distributor in the aforementioned integrated biomass boiler fuel feeding and drying system is in a conical shape. The conical structure can naturally guide the fuel to disperse from the center to the periphery, avoiding accumulation in a single area, ensuring uniform combustion cross-sectional load in the furnace, and reducing local high temperature or unburned phenomenon. Moreover, the inclination angle of the conical surface is usually ≥ 60°, so that gravity flow can be utilized to reduce fuel adhesion or retention, and the distributor is suitable for high-moisture biomass fuel.

[0015] Correspondingly, the application also provides a control method of the integrated biomass boiler fuel feeding and drying system. First, according to the moisture content of the biomass fuel, the control system controls the adjusting mechanism to adjust the gap between the material blocking door and the chain grate, and sets the running speed of the chain grate; when the boiler body is running, the control system controls the material distributor, the hot smoke conveying fan, the exhaust fan and the driving device to start synchronously; after the high-moisture biomass fuel is conveyed to the top of the stock bin, it enters the feeding port and falls into the stock bin uniformly under the action of the material distributor; in this process, the material level detector detects the amount of fuel entering the stock bin in real time, so that the material level is maintained within the set position, and the balance between the amount of fuel entering and the amount of fuel consumed by the boiler body is ensured; the driving device drives the chain grate to move uniformly from front to back, drives the fuel in the stock bin to move backward, and drives the fuel to pass through the material blocking door into the drying and heat exchange chamber; under the blocking of the material blocking door, the fuel forms a uniform flat layer on the discharge surface of the chain grate; the hot smoke conveying fan extracts the hot smoke in the smoke exhaust pipeline and conveys it to the hot smoke distribution chamber through the hot smoke pipeline; after the hot smoke enters the hot smoke distribution chamber, it moves upward, passes through the chain grate, exchanges heat with the fuel on the discharge surface, and carries away the moisture in the fuel; at this time, the hot smoke becomes low-temperature flue gas and continues to move upward, flows out of the drying and heat exchange chamber, and finally flows back into the smoke exhaust pipeline through the flue gas pipeline and is exhausted 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 combustion enters the smoke exhaust pipeline; during the combustion of the fuel, if the pressure of the steam generated by the boiler body is less than the set value, the control system controls the adjusting mechanism to start, drives the material blocking door to rise, increases the gap between the material blocking door and the chain grate, and increases the fuel feeding amount; at the same time, the control system converts the net value of the moisture carried by the flue gas according to the flue gas temperature at the outlet of the drying and heat exchange chamber detected by the temperature detector, adjusts the opening size of the flow regulating valve, and adjusts the amount of hot smoke entering the hot smoke distribution chamber, so as to ensure the drying effect.

[0016] In the process of drying the smoke from the hot smoke pipeline into the hot smoke distribution chamber, and then flowing out of the drying and heat exchange chamber to the flue gas pipeline, a slight positive pressure is formed in the drying and heat exchange chamber, so that the flame in the furnace can be prevented from backfiring into the drying and heat exchange chamber.

[0017] The control method of the integrated biomass boiler fuel feeding and drying system can control the material distributor, the hot smoke conveying fan, the exhaust fan and the driving device to start synchronously, so that the fuel supply, drying and combustion can be carried out synchronously, and each link does not need to carry out logical control by itself, which is convenient to operate and easy to implement; at the same time, during the combustion of the fuel, the gap between the material blocking door and the chain grate is adjusted according to the detected pressure of the steam generated by the boiler body, and the amount of hot smoke entering the hot smoke distribution chamber is adjusted according to the detected flue gas temperature at the outlet of the drying and heat exchange chamber, so as to convert the net value of the moisture carried by the flue gas, so as to ensure the drying effect of the fuel and improve the combustion efficiency. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the integrated biomass boiler fuel feeding and drying system of this application;

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

[0020] 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

[0021] 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.

[0022] See Figure 1 and Figure 2 ( Figure 1The integral biomass boiler fuel feeding and drying system of the present application comprises a feeding device 1, a drying device 2, a boiler body 3 and an exhaust device 4 arranged in sequence, wherein the exhaust device 4 comprises an exhaust pipeline 41 and an exhaust fan 42; the feeding device 1 comprises a stock bin 11; the stock bin 11 is provided with an inlet 12 at the top, and the inlet 12 is provided with a distributor 13; the boiler body 3 comprises an internal furnace 301, and the bottom of the internal furnace 301 is provided with a chain grate 31; the chain grate 31 is connected with a driving device 5 and can move under the driving of the driving device 5, and the front end of the chain grate 31 extends to the bottom of the stock bin 11 and separates the drying device 2 into a drying and heat exchange chamber 201 and a hot smoke distribution chamber 202; the stock bin 11, the drying and heat exchange chamber 201 and the internal furnace 301 are communicated with each other; the hot smoke distribution chamber 202 is communicated with the exhaust pipeline 41 through a hot smoke pipeline 21; the hot smoke pipeline 21 is provided with a hot smoke conveying fan 22 for conveying the waste heat-containing flue gas in the exhaust pipeline 41 to the hot smoke distribution chamber 202; the drying and heat exchange chamber 201 is communicated with the exhaust pipeline 41 through a waste gas pipeline 23; and the connection position of the hot smoke pipeline 21 and the exhaust pipeline 41 is located at the front side of the connection position of the waste gas pipeline 23 and the exhaust pipeline 41.

[0023] The integral biomass boiler fuel feeding and drying system of the present application systematically integrates the boiler body 3 (including the chain grate and the cooperating furnace arch, secondary air, etc.) and the feeding device 1, fully utilizes the power, control system and feeding and distributing functions of the original boiler body, sets the drying device 2 between the boiler body 3 and the feeding device 1, and extends the chain grate 31 of the boiler body 3 to the drying device 2 and the feeding device 1, so that the fuel feeding, drying and combustion are simultaneously performed during the operation, the fuel stacking space is saved, the fuel storage risk is reduced, the drying device 2 is separated into the drying and heat exchange chamber 201 and the hot smoke distribution chamber 202 by the chain grate 31 and is communicated with the exhaust pipeline 41, so that the moisture in the fuel is taken away by the flue gas with waste heat discharged from the boiler body 3 and is discharged to the exhaust pipeline 41 at the tail, the moisture in the fuel is prevented from entering the internal furnace 301 to participate in the combustion and heat exchange, the low-moisture fuel is burned and heat-exchanged in the boiler body 3, the advantages of the chain biomass combustion boiler are greatly exerted, the problems such as low combustion efficiency, increased safety hazards, aggravated environmental pollution and poor operation stability of the chain grate using high-moisture biomass fuel in the prior art are solved, and the chain biomass combustion boiler has the advantages of high efficiency, environmental protection, strong fuel adaptability, convenient operation and high automation degree.

[0024] In the prior art, the chain grate area in the furnace 301 of the boiler body 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 application, after the high-moisture biomass fuel is dried by the drying device 2, the moisture carried by the fuel is greatly reduced, and the combustion efficiency of the fuel in the boiler body 3 is improved (the combustion efficiency can be improved by more than 3%), so the length of the grate burnout zone 312 of the boiler body 3 in the present application can be reduced by about 50% (i.e., the grate burnout zone 312 accounts for more than 25% of the total grate length), thereby reducing the cost of the boiler body 3, and at the same time, the uncontrollable excess air quantity of the grate burnout zone 312 can be reduced by more than 30%, thereby optimizing the air quantity for combustion.

[0025] Embodiment:

[0026] In the present embodiment, a material blocking door 6 is arranged between the material stacking bin 11 and the drying heat exchange chamber 201, and an adjusting mechanism is arranged on the material blocking door 6; the adjusting mechanism is electrically connected with a control system, and is used to drive the material blocking door 6 to move up and down, so as to adjust the gap between the material blocking door 6 and the chain grate 31. In this way, the gap between the material blocking door 6 and the chain grate 31 can be automatically adjusted according to the moisture content of the biomass fuel before the fuel is burned, and according to the steam pressure generated by the boiler body 3 during the fuel burning process, so as to ensure the fuel feeding quantity.

[0027] Further, a material level detector 14 is arranged on the material stacking bin 11, and is used to detect the quantity of the fuel entering the material stacking bin 11, so as to maintain the material level within a set position. The stable material level provides a stable static pressure for the fuel to be evenly and gently laid on the chain grate 31 in the boiler body 3 through the mechanical material blocking door, and also ensures the balance between the feeding quantity and the combustion consumption of the boiler body 3.

[0028] In the present embodiment, a hood 24 is arranged on the top of the drying heat exchange chamber 201, the hood 24 has a trapezoidal shape with a small top and a large bottom, and the outlet of the hood 24 is connected with a waste gas pipeline 23. In this way, the waste gas can be more quickly guided to the waste gas pipeline 23 after entering the hood 24, so as to reduce the residence time of the waste gas in the hood 24, thereby improving the exhaust efficiency.

[0029] Further, the outlet of the smoke hood 24 is provided with a temperature detector 25, and the outlet of the hot smoke pipeline 21 is provided with a flow regulating valve 26; the temperature detector 25 and the flow regulating valve 26 are electrically connected with the control system respectively. After the fuel is dried by the hot smoke, the water in the fuel is taken away by the hot smoke and becomes the exhaust gas, and the exhaust gas is in a saturated state of steam; by measuring the temperature of the exhaust gas at the outlet of the smoke hood 24, the net value of the water carried by the exhaust gas can be converted, so that the opening size of the flow regulating valve 26 can be adjusted according to the water content, so as to adjust the amount of hot smoke entering the hot smoke distribution chamber 202, and ensure the drying effect.

[0030] Further, the outlet of the smoke hood 24 is provided with a filter screen 27. In this way, the impurities in the exhaust gas can be filtered out by the filter screen 27 before being discharged to the outside, so as to further reduce the pollution to the environment.

[0031] In the embodiment, the water-cooled fireproof door 7 is arranged between the drying heat exchange chamber 201 and the hearth 301, which is used to shield the flame in the hearth 301 from radiating to the fuel in the drying heat exchange chamber 201, and increase the operation reliability of the drying system of the present application.

[0032] In the embodiment, the distributor 13 is conical. The conical structure can naturally guide the fuel to disperse from the center to the periphery, avoid accumulation in a single area, ensure the uniformity of the combustion cross-sectional load in the furnace, and reduce the local high temperature or unburned phenomenon; and the inclination angle of the conical surface is generally ≥60°, so that the gravity flow can be utilized, the fuel adhesion or retention is reduced, and the distribution operation of the high-moisture biomass fuel is suitable.

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

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

[0035] When the boiler body 3 is in operation, the distributor 13, the hot smoke conveying fan 22, the exhaust fan 42 and the driving device 5 are synchronously started by the control system; after the high-moisture biomass fuel is conveyed (conveyed by another feeding device) to above the stock bin 11, it enters the feeding inlet 12 and is uniformly dropped into the stock bin 11 under the action of the distributor 13; in this process, the material level detector 14 detects the amount of fuel entering the stock bin 11 in real time, so that the material level is maintained within the set position, and the balance between the amount of fuel entering and the amount of fuel consumed by the boiler body 3 is ensured; the driving device 5 drives the chain grate 31 to move uniformly from front to back, drives the fuel in the stock bin 11 to move backward, and passes through the blocking door 6 into the drying and heat exchange chamber 201; the fuel is blocked by the blocking door 6 and forms a uniform flat fuel layer on the discharge surface of the chain grate 31; the hot smoke conveying fan 22 extracts the hot smoke in the smoke exhaust pipeline 41 and conveys it to the hot smoke distribution chamber 202 through the hot smoke pipeline 21; after the hot smoke enters the hot smoke distribution chamber 202, it moves upward and passes through the chain grate 31 to exchange heat with the fuel on the discharge surface and take away 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 and heat exchange chamber 201, and finally flows back into the smoke exhaust pipeline 41 through the exhaust gas pipeline 23 and is exhausted 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 and enters the furnace 301 to burn and release heat; the hot smoke generated by the burning enters the smoke exhaust pipeline 41.

[0036] During the fuel combustion process, if it is detected that the pressure of the steam generated by the boiler body 3 is less than the set value, the control system controls the adjusting mechanism to start and drive the blocking door 6 to rise, thereby increasing the gap between the blocking door 6 and the chain grate 31 and increasing the amount of fuel feeding; 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 smoke hood 24 detected by the temperature detector 25 (a dry and wet bulb thermometer is used in this embodiment) to adjust the opening size of the flow regulating valve 26, so as to adjust the amount of hot smoke entering the hot smoke distribution chamber 202 and ensure the drying effect.

[0037] The general description of the invention involved in the present application and the description of the specific embodiments thereof should not be understood as limiting the technical solutions of the invention. Based on the disclosure of the present application, those skilled in the art can add, reduce or combine the disclosed technical features in the general description or / and the specific embodiments (including the embodiments) without violating the elements of the invention involved, to form other technical solutions within the protection scope of the present application.

Claims

1. A control method for an integrated biomass boiler fuel feeding and drying system, characterized in that: The integrated biomass boiler fuel feeding and drying system 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 stockpile (11); a feed inlet (12) is provided above the stockpile (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 moves under the drive of the drive device (5), and the front end of the chain grate (31) extends forward to the stockpile (11). The bottom of the drying 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 exhaust pipe (41) through the hot smoke pipe (21); the hot smoke pipe (21) is equipped with a hot smoke conveying fan (22) for drawing the flue gas containing waste heat in the exhaust pipe (41) to the hot smoke 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 smoke 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); A baffle gate (6) is provided between the material storage bin (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); 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; 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.

2. The control method for 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).

3. The control method for the integrated biomass boiler fuel feeding and drying system according to claim 2, 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.

4. The control method for the integrated biomass boiler fuel feeding and drying system according to claim 3, characterized in that: The smoke hood (24) is equipped with a filter screen (27) at its outlet.

5. The control method for 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).

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

7. The control method for the integrated biomass boiler fuel feeding and drying system according to claim 1, 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.

Images