High-water-content biomass fuel pretreatment and efficient combustion device

Abstract

The invention discloses a pretreatment and efficient combustion device for high-water-content biomass fuel. The pretreatment and efficient combustion device comprises a sealed feeding system, a three-stage gradient drying unit, a crushing and homogenizing mechanism and a rotational flow combustion chamber which are connected in sequence. The three-stage gradient drying unit is composed of a low-temperature zone, a medium-temperature zone and a high-temperature zone, material turning plates which are arranged in a staggered mode are arranged in all the temperature zones, a steam coil pipe is arranged in the medium-temperature zone, an inlet of the low-temperature zone is connected with a 150-200 DEG C low-temperature smoke outlet of the combustion chamber, and the high-temperature zone is connected with an independent hot air generator. Through three-stage gradient drying and combustion chamber structure innovation, the drying energy consumption is reduced; due to the multi-stage air distribution and rotational flow design of the combustion chamber, the combustion efficiency of biomass fuel with the water content of 50% is remarkably improved; the flue gas waste heat cascade recycling can reduce the external energy input of the system; the built-in crushing mechanism solves the problem of caking of high-humidity materials; and the modular design adapts to different types of biomass fuels, so that the comprehensive operation cost is reduced.

Description

Technical Field

[0001] This application relates to the field of biomass fuel processing technology, specifically to a pretreatment and high-efficiency combustion device for high-moisture-content biomass fuel. Background Technology

[0002] When high-moisture-content biomass fuels are directly burned, their combustion efficiency drops significantly. Traditional methods for processing such fuels require separate drying equipment, which is extremely energy-intensive, accounting for over 60% of the total energy consumption of the entire processing system. Furthermore, existing combustion devices are poorly designed to handle fluctuations in the moisture content of high-moisture fuels, directly leading to unstable combustion processes, generally low thermal efficiency (typically below 65%), and excessive emissions of pollutants such as carbon monoxide (CO) and nitrogen oxides (NOx). Although some technologies attempt to improve this situation through pre-drying, the separation of drying equipment from the combustion system introduces new problems such as high energy loss, increased overall system complexity, and inefficient utilization of exhaust heat. Summary of the Invention

[0003] To address this, this application provides a high-moisture-content biomass fuel pretreatment and high-efficiency combustion device to solve the problems of high energy loss, increased overall system complexity, and incomplete utilization of exhaust gas waste heat in existing technologies.

[0004] To achieve the above objectives, this application provides the following technical solution:

[0005] A high-moisture-content biomass fuel pretreatment and high-efficiency combustion device, comprising a sequentially connected sealed feeding system, a three-stage gradient drying unit, a crushing and homogenizing mechanism, and a swirl combustion chamber;

[0006] The three-stage gradient drying unit consists of a low-temperature zone, a medium-temperature zone, and a high-temperature zone. Each temperature zone is equipped with staggered turning plates. The medium-temperature zone is equipped with a steam coil. The inlet of the low-temperature zone is connected to the 150-200℃ low-temperature flue gas outlet of the combustion chamber. The high-temperature zone is connected to an independent hot air generator.

[0007] The crushing and homogenizing mechanism includes a twin-shaft shear crusher and a humidity sensor, and its outlet is connected to the combustion chamber via a screw feeder.

[0008] The swirl combustion chamber adopts a vertical cylindrical structure, with tangentially arranged secondary air inlets on the side walls and a perforated plate primary air distributor installed at the bottom. The flue gas is discharged through the tail purification system.

[0009] Preferably, the temperature control of the three-stage gradient drying unit meets the following requirements: the low temperature zone is maintained at 80-100℃, the medium temperature zone at 120-150℃, the high temperature zone at 180-220℃, and the material residence time is adjustable from 30 to 50 minutes.

[0010] Preferably, the steam coil is connected to an outdoor waste heat boiler outside the combustion chamber to generate 0.8-1.5MPa saturated steam using waste heat from the flue gas.

[0011] Preferably, the dual-shaft shear crusher of the crushing and homogenizing mechanism is equipped with a variable frequency motor, and the speed is dynamically adjusted according to the moisture content signal fed back by the humidity sensor. The adjustment logic is: when the moisture content is >60%, the speed is ≤15rpm, and when the moisture content is 40%-60%, the speed is 20-35rpm.

[0012] Preferably, the humidity sensor is a microwave resonant detector that monitors the material moisture content fluctuation in real time and feeds it back to the central controller to adjust the rotation speed and feeding rate of the dual-shaft shear crusher.

[0013] Preferably, the secondary air inlet is equipped with adjustable guide vanes, and the angle of the adjustable guide vanes is automatically adjusted according to the data of the combustion chamber temperature sensor to keep the flue gas swirl intensity at a turbulence index Re≥5000.

[0014] Preferably, the automatic adjustment logic of the adjustable guide vanes is as follows: when the temperature is >950℃, the vane angle is adjusted to 15°-25°, and when the temperature is <850℃, it is adjusted to 35°-45°.

[0015] Preferably, the sealed feeding system adopts a squeeze drainage structure with a squeeze pressure of 0.4-0.8 MPa, which reduces the initial moisture content of the material by 5%-10%.

[0016] Preferably, the fuel input pipe of the independent hot air generator is equipped with a gas proportional valve, which is controlled by a steam pressure sensor and a combustion chamber temperature sensor in the waste heat boiler. The control logic of the independent hot air generator is as follows:

[0017] When the steam pressure in the waste heat boiler is <0.8MPa and the combustion chamber temperature is <850℃, the proportional valve opening is increased to 70%-00%, and the hot air temperature is increased to above 220℃.

[0018] When the steam pressure in the waste heat boiler is ≥1.2MPa or the combustion chamber temperature is >950℃, the proportional valve opening is reduced to 30%-50%, and the hot air temperature is maintained at 180±5℃.

[0019] Compared with the prior art, this application has at least the following beneficial effects:

[0020] This invention reduces drying energy consumption through three-stage gradient drying and innovative combustion chamber structure; the multi-stage air distribution and swirl design of the combustion chamber significantly improves the combustion efficiency of biomass fuel with a moisture content of 50%; the cascade recovery of flue gas waste heat reduces the system's external energy input; the built-in crushing mechanism solves the problem of agglomeration of high-moisture materials; and the modular design adapts to different types of biomass fuels, thus reducing overall operating costs. Attached Figure Description

[0021] To more intuitively illustrate the prior art and this application, exemplary drawings are provided below. It should be understood that the specific shapes and structures shown in the drawings should not generally be regarded as limiting conditions for implementing this application; for example, based on the technical concept disclosed in this application and the exemplary drawings, those skilled in the art are able to easily make conventional adjustments or further optimizations to the addition / reduction / classification, specific shapes, positional relationships, connection methods, size ratios, etc. of certain units (components).

[0022] Figure 1 This is an overall schematic diagram of the high moisture content biomass fuel pretreatment and high efficiency combustion device of this application.

[0023] In the picture:

[0024] 110. Sealed feeding system;

[0025] 200. Three-stage gradient drying unit; 210. Low temperature zone; 211. Tilting plate; 220. Medium temperature zone; 230. High temperature zone; 240. Steam coil;

[0026] 300. Crushing and homogenizing mechanism; 310. Twin-shaft shear crusher; 320. Humidity sensor; 330. Screw feeder;

[0027] 400. Swirl combustion chamber; 410. Low-temperature flue gas outlet; 420. Secondary air inlet; 421. Adjustable guide vanes; 430. Perforated plate primary air distributor; 440. Combustion chamber temperature sensor;

[0028] 500. Independent hot air generator; 510. Gas proportional valve;

[0029] 600. Purification system; 700. Waste heat boiler; 710. Steam pressure sensor; 800. Central controller. Detailed Implementation

[0030] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] like Figure 1As shown, this application discloses a high moisture content biomass fuel pretreatment and high efficiency combustion device, including a sealed feeding system 110, a three-stage gradient drying unit 200, a crushing and homogenizing mechanism 300 and a swirl combustion chamber 400 connected in sequence.

[0032] The three-stage gradient drying unit 200 consists of a low-temperature zone 210, a medium-temperature zone 220, and a high-temperature zone 230. Each zone is equipped with staggered turning plates 211. The medium-temperature zone 220 is equipped with a steam coil 240. The inlet of the low-temperature zone 210 is connected to the 150-200℃ low-temperature flue gas outlet 410 of the combustion chamber 400. The high-temperature zone 230 is connected to an independent hot air generator 500.

[0033] The crushing and homogenizing mechanism 300 includes a dual-shaft shear crusher 310 and a humidity sensor 320, and its outlet is connected to the combustion chamber 400 via a screw feeder 330.

[0034] The swirl combustion chamber 400 adopts a vertical cylindrical structure, with tangentially arranged secondary air inlets 420 on the side wall and a perforated plate primary air distributor 430 installed at the bottom. The flue gas is discharged through the tail purification system 600.

[0035] This device achieves efficient processing of high-moisture biomass through a three-stage gradient drying and closed-loop energy system in the combustion chamber: materials with a moisture content ≥50% enter the low-temperature zone 210, where surface moisture is removed by the 150-200℃ low-temperature flue gas temperature drawn from the combustion chamber; the medium-temperature zone 220 is indirectly heated by steam coils 240 generated by a waste heat boiler 700, breaking down the bound water inside the material; the high-temperature zone 230 is supplied with 180-220℃ hot air by an independent hot air generator for deep drying. After drying, the material is homogenized by a twin-shaft shear crusher 310, with the speed dynamically adjusted according to the moisture content to prevent agglomeration, and then fed into the cyclone combustion chamber 400 via a screw feeder 330. The combustion chamber uses a multi-hole variable-aperture air distributor 430 to supply air, which, together with tangential secondary air 420, generates cyclone, enabling stable combustion of high-moisture fuel at 850-950℃. The high-temperature flue gas generated by combustion is 400-500℃. 70-80% of it enters the waste heat boiler to produce steam for the medium-temperature zone, and the remaining low-temperature flue gas is recycled to the front end of the drying process, forming a closed loop of energy cascade utilization.

[0036] The temperature control of the three-stage gradient drying unit 200 meets the following requirements: the low-temperature zone 210 is maintained at 80-100℃, the medium-temperature zone 220 at 120-150℃, and the high-temperature zone 230 at 180-220℃, with the material residence time adjustable from 30-50 minutes. Controlling the temperature of the three-stage drying zones (low-temperature zone 80-100℃, medium-temperature zone 120-150℃, high-temperature zone 180-220℃, and material residence time, for example, 30-50 minutes) rapidly reduces the moisture content of the material and decreases energy consumption.

[0037] The steam coil 240 is connected to the external waste heat boiler 700 of the combustion chamber 400, which uses the waste heat of the flue gas to generate 0.8-1.5MPa saturated steam, which not only prevents flue gas pollutants from contacting materials, but also improves the utilization rate of flue gas waste heat. The steam condensate can be recycled to the boiler feedwater system.

[0038] The dual-shaft shear crusher 310 of the crushing and homogenizing mechanism 300 is equipped with a variable frequency motor. The speed is dynamically adjusted according to the moisture content signal fed back by the humidity sensor 320. The adjustment logic is as follows: when the moisture content is >60%, the speed is ≤15 rpm; when the moisture content is 40%-60%, the speed is 20-35 rpm. The dual-shaft shear crusher 310 dynamically adjusts the speed according to the feedback from the humidity sensor. When the moisture content is high (>60%), the speed is low at 15 rpm to prevent sticking; when the moisture content is medium (40-60%), the speed is medium at 35 rpm to improve efficiency. This ensures that materials with different moisture contents are sheared into homogeneous particles of 5-10 mm, thereby reducing crushing energy consumption and ensuring continuous and stable feeding to the combustion chamber.

[0039] The humidity sensor 320 adopts a microwave resonant detector to monitor the fluctuation of material moisture content in real time and feed it back to the central controller 800 to adjust the rotation speed and feeding rate of the dual-shaft shear crusher 310. The microwave resonant humidity sensor can penetrate and detect the internal moisture content of the material in real time, ensuring the accuracy of the detection. Its signal is linked to the central controller 800 to adjust the crusher rotation speed and the screw feeder speed, forming a closed-loop control of "detection-crushing-conveying", which makes the moisture content of the material fed into the combustion chamber more stable.

[0040] The secondary air inlet 420 is equipped with adjustable guide vanes 421. The angle of the adjustable guide vanes 421 is automatically adjusted according to the data of the combustion chamber temperature sensor 440 to keep the flue gas swirl intensity at a turbulence index Re≥5000. When the temperature is high >950°, the angle is 25° to reduce the swirl intensity and prevent slagging. When the temperature is low <850°, the angle is 45° to increase turbulence and maintain the flue gas turbulence index Re≥5000 to ensure sufficient mixing of flue gas and air.

[0041] The automatic adjustment logic of the adjustable guide vane 421 is as follows: when the temperature is >950℃, the vane angle is adjusted to 15°-25°, and when the temperature is <850℃, it is adjusted to 35°-45°. The correlation between the angle of the adjustable guide vane 421 and the temperature controls the small angle at high temperatures and the large angle at low temperatures, which constitutes the core guarantee for combustion stability. For example, when the biomass calorific value fluctuates by ±20%, the system automatically adjusts the vane angle between 15-45° to control the furnace temperature fluctuation within ±30℃, avoiding fire extinguishing or overheating accidents caused by the lag of manual intervention.

[0042] The sealed feeding system 110 adopts a squeeze drainage structure. For example, after feeding, the material is squeezed by a pressure roller with a squeezing pressure of 0.4-0.8 MPa, which reduces the initial moisture content of the material by 5%-10%, thereby squeezing out the free water inside the material and reducing the initial moisture content by 5%-10%, such as from 60% to 54%, which significantly reduces the drying load.

[0043] The independent hot air generator 500 is equipped with a gas proportional valve 510 on its fuel input pipeline. The gas proportional valve 510 is controlled by a steam pressure sensor 710 and a combustion chamber temperature sensor 440 in the waste heat boiler 700. The control logic of the independent hot air generator 500 is as follows:

[0044] When the steam pressure in the waste heat boiler 700 is <0.8MPa and the temperature in the combustion chamber 400 is <850℃, the opening of the proportional valve is increased to 70%-00%, and the hot air temperature is increased to above 220℃.

[0045] When the steam pressure in the waste heat boiler 700 is ≥1.2MPa or the temperature in the combustion chamber 400 is >950℃, the proportional valve opening is reduced to 30%-50%, and the hot air temperature is maintained at 180±5℃.

[0046] The hot air generator is linked to the steam pressure and combustion temperature via the gas proportional valve 510. When the output of the waste heat boiler is insufficient, it automatically opens the valve when the supplementary steam pressure is <0.8MPa and the furnace temperature is <850℃. When there is excess energy, it lowers the operating pressure to >1.2MPa or the furnace temperature is >950℃ and closes the valve, so that the temperature of the drying high-temperature zone is stabilized within ±5℃. Its flue gas is connected to the inlet of the waste heat boiler to realize energy recovery, improve the overall fuel utilization rate, and is more energy-efficient than the independent operation system.

[0047] The technical features of the above embodiments can be combined in any way as long as there is no contradiction in the combination of these technical features. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; these embodiments not explicitly written should also be considered to be within the scope of this specification.

Claims

1. A high-moisture-content biomass fuel pretreatment and high-efficiency combustion device, characterized in that, It includes a sealed feeding system (110), a three-stage gradient drying unit (200), a crushing and homogenizing mechanism (300), and a swirl combustion chamber (400) connected in sequence; The three-stage gradient drying unit (200) consists of a low-temperature zone (210), a medium-temperature zone (220) and a high-temperature zone (230). Each temperature zone is equipped with staggered turning plates (211). The medium-temperature zone (220) is equipped with a steam coil (240). The inlet of the low-temperature zone (210) is connected to the 150-200℃ low-temperature flue gas outlet (410) of the swirl combustion chamber (400). The high-temperature zone (230) is connected to an independent hot air generator (500). The crushing and homogenizing mechanism (300) includes a twin-shaft shear crusher (310) and a humidity sensor (320), and its outlet is connected to a swirl combustion chamber (400) via a screw feeder (330). The swirl combustion chamber (400) adopts a vertical cylindrical structure, with tangentially arranged secondary air inlets (420) on the side wall and a perforated plate primary air distributor (430) installed at the bottom. The flue gas is discharged through the tail purification system (600).

2. The high-moisture-content biomass fuel pretreatment and high-efficiency combustion device according to claim 1, characterized in that, The temperature control of the three-stage gradient drying unit (200) meets the following requirements: the low temperature zone (210) is maintained at 80-100℃, the medium temperature zone (220) is maintained at 120-150℃, the high temperature zone (230) is maintained at 180-220℃, and the material residence time is adjustable from 30 to 50 minutes.

3. The high-moisture-content biomass fuel pretreatment and high-efficiency combustion device according to claim 2, characterized in that, The steam coil (240) is connected to the external waste heat boiler (700) of the swirl combustion chamber (400) to generate 0.8-1.5MPa saturated steam using the waste heat of the flue gas.

4. The high-moisture-content biomass fuel pretreatment and high-efficiency combustion device according to claim 1, characterized in that, The crushing and homogenizing mechanism (300) is equipped with a dual-shaft shear crusher (310) with a variable frequency motor. The speed is dynamically adjusted according to the moisture content signal fed back by the humidity sensor (320). The adjustment logic is: when the moisture content is >60%, the speed is ≤15rpm, and when the moisture content is 40%-60%, the speed is 20-35rpm.

5. The high-moisture-content biomass fuel pretreatment and high-efficiency combustion device according to claim 4, characterized in that, The humidity sensor (320) is a microwave resonant detector that monitors the fluctuation of material moisture content in real time and feeds it back to the central controller (800) to adjust the rotation speed and feeding rate of the dual-shaft shear crusher (310).

6. The high-moisture-content biomass fuel pretreatment and high-efficiency combustion device according to claim 1, characterized in that, The secondary air inlet (420) is equipped with adjustable guide vanes (421). The angle of the adjustable guide vanes (421) is automatically adjusted according to the data of the combustion chamber temperature sensor (440) so that the flue gas swirl intensity is maintained at a turbulence index Re≥5000.

7. The high-moisture-content biomass fuel pretreatment and high-efficiency combustion device according to claim 6, characterized in that, The automatic adjustment logic of the adjustable guide vane (421) is as follows: when the temperature is >950℃, the vane angle is adjusted to 15°-25°, and when the temperature is <850℃, it is adjusted to 35°-45°.

8. The high-moisture-content biomass fuel pretreatment and high-efficiency combustion device according to claim 1, characterized in that, The sealed feeding system (110) adopts a squeeze drainage structure with a squeeze pressure of 0.4-0.8 MPa, which reduces the initial moisture content of the material by 5%-10%.

9. The high-moisture-content biomass fuel pretreatment and high-efficiency combustion device according to claim 1, characterized in that, The independent hot air generator (500) is equipped with a gas proportional valve (510) on its fuel input pipeline. The gas proportional valve (510) is controlled by a steam pressure sensor (710) and a combustion chamber temperature sensor (440) in the waste heat boiler (700). The control logic of the independent hot air generator (500) is as follows: When the steam pressure in the waste heat boiler (700) is <0.8MPa and the temperature of the swirl combustion chamber (400) is <850℃, the opening of the proportional valve is increased to 70%-00%, and the hot air temperature is increased to above 220℃. When the steam pressure in the waste heat boiler (700) is ≥1.2MPa or the temperature of the swirl combustion chamber (400) is >950℃, the opening of the proportional valve is reduced to 30%-50% and the hot air temperature is maintained at 180±5℃.

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