A full load multi-coal species modulated oxy-combustion system and control method

Abstract

The application relates to a full-load multi-coal-species modulation oxygen-enriched combustion system and a control method. The combustion system comprises a burner, a furnace, an economizer and a dust remover which are sequentially connected; a first flue gas pipeline of a flue gas circulation pipeline is connected with the furnace, a second flue gas pipeline is connected with the outlet of the economizer, and a third flue gas pipeline is connected with the dust remover; a first inlet of a switching device is respectively communicated with the outlet of the first flue gas pipeline, the outlet of the second flue gas pipeline, the outlet of the third flue gas pipeline and the outlet of a primary air powder pipeline; a second inlet of a separation device is communicated with the first outlet of the switching device, the third outlet of the separation device discharges a gas flow with a concentration greater than that of the fourth outlet; a primary air channel of an air supply device is respectively communicated with the second outlet of the switching device, the third outlet and the fourth outlet of the separation device, and the outlet end of the primary air channel is communicated with the furnace. The application has a large adjustable range of concentration ratio, high utilization rate of circulating flue gas, remarkable effects of stable combustion and nitrogen reduction.

Description

Technical Field

[0001] This application belongs to the field of pulverized coal combustion technology, and specifically relates to a full-load multi-coal type modulated oxygen-enriched combustion system and its control method. Background Technology

[0002] In related technologies, to improve combustion efficiency and reduce pollutant emissions, rich-lean separation combustion technology is used to separate the primary air and pulverized coal gas flow into two gas streams with significantly different concentrations: a rich phase and a lean phase. The rich phase gas stream has a higher pulverized coal concentration, which reduces the ignition heat of the pulverized coal, accelerates the chemical reaction rate, and increases the flame propagation speed, thereby improving combustion stability and efficiency. Existing pulverized coal rich-lean separation combustion equipment performs well under normal load conditions, but when operating at low loads (<40% of rated load), it is prone to safety hazards such as intensified flame pulsation, decreased combustion efficiency, and even burner flameout due to uneven oxygen concentration distribution in the combustion zone and excessively low local excess air coefficients.

[0003] In addition, the combustion parameters are mostly fixed for different load conditions of the boiler, lacking the ability to make multi-dimensional and precise adjustments based on load and coal quality changes, thus failing to fully realize the overall optimization benefits and limiting combustion efficiency. Summary of the Invention

[0004] Based on the above-mentioned technical problems, this application provides a full-load multi-coal type modulated oxygen-enriched combustion system and control method, which can perform multi-dimensional and precise regulation according to load and coal quality changes to optimize combustion efficiency.

[0005] This application is achieved through the following technical solution: In a first aspect, this application provides a full-load multi-coal type modulated oxygen-enriched combustion system, the combustion system comprising: a burner, a furnace, an economizer, and a dust collector connected in sequence; a flue gas circulation pipeline, including a first flue gas pipeline, a second flue gas pipeline, and a third flue gas pipeline, wherein the inlet of the first flue gas pipeline is connected to the furnace, and a first fan and a first regulating valve are provided on the first flue gas pipeline; the inlet of the second flue gas pipeline is connected to the outlet of the economizer, and a second fan and a second regulating valve are provided on the second flue gas pipeline; the inlet of the third flue gas pipeline is connected to the outlet of the dust collector, and a third fan and a third regulating valve are provided on the third flue gas pipeline; a primary air-coal pipeline; and a switching device having a first inlet, a first outlet, and a second outlet, wherein the first inlet of the switching device is switchably connected to the first outlet and the second outlet. The first inlet is connected to one of the outlets, and the first inlet is connected to the outlet of the first flue gas pipeline, the outlet of the second flue gas pipeline, the outlet of the third flue gas pipeline, and the outlet of the primary air-coal pipeline. The concentration separation device has a second inlet, a third outlet, and a fourth outlet. The second inlet of the concentration separation device is connected to the third outlet and the fourth outlet. The second inlet of the concentration separation device is connected to the first outlet of the switching device. The concentration of the gas flow discharged from the third outlet is greater than the concentration of the gas flow discharged from the fourth outlet. The air supply device includes a primary air duct. The primary air duct has an air supply end and an air outlet end. The air supply end of the primary air duct is connected to the second outlet of the switching device, the third outlet of the concentration separation device, and the fourth outlet of the primary air duct. The air outlet end of the primary air duct is connected to the furnace.

[0006] In some embodiments, the switching device includes a valve body, a first branch pipe, a second branch pipe, a third branch pipe, and a valve plate, wherein: the first branch pipe, the second branch pipe, and the third branch pipe are respectively connected to the periphery of the valve body at intervals; the end of the first branch pipe away from the valve body is configured as the first inlet; the end of the second branch pipe away from the valve body is configured as the first outlet; and the end of the third branch pipe away from the valve body is configured as the third outlet; the valve body is provided with a first port communicating with the first branch pipe, a second port communicating with the second branch pipe, and a third port communicating with the third support; the valve plate is located in the valve body, the valve plate is rotatably connected to the valve body, and is located between the second port and the third port; the valve plate can controllably seal one of the second port and the third port.

[0007] In some implementations, the cross-sectional area of ​​the second inlet is adjustable.

[0008] In some implementations, the primary air duct is horizontal in direction, and the two ends of the primary air duct are an air supply end and an air outlet end, respectively. The air supply end is provided with a first connecting port, a second connecting port and a third connecting port with decreasing heights in sequence. The first connecting port is connected to the third outlet, the second connecting port is connected to the second outlet, and the third connecting port is connected to the fourth outlet.

[0009] In some embodiments, the air supply device further includes: a separation window disposed within the primary air duct, the separation window comprising multiple separation blades spaced apart along the axial direction of the primary air duct, the multiple separation blades being rotatably connected to the sidewall of the primary air duct and inclinedly disposed within the primary air duct, the end of the separation blades near the air outlet being higher than the end near the air supply end; and a blunt body disposed within the primary air duct, along the axial direction of the primary air duct, the blunt body being disposed between the separation window and the air supply end, the thickness of the blunt body at the end facing the air supply end being less than the thickness of the blunt body at the end facing the air outlet, and the distance from the blunt body to the side of the air outlet being adjustable.

[0010] In some embodiments, the air supply device further includes an adjustment assembly for driving the separation plates to rotate. The adjustment assembly includes: a second driving member having a telescopic end that reciprocates along an axial direction parallel to the primary air channel; a first driving rod connected to the telescopic end of the second driving member, the first driving rod being arranged along an axial direction parallel to the primary air channel, at least a portion of the first driving rod penetrating into the primary air channel; a connecting plate disposed within the primary air channel, the connecting plate being connected to the first driving rod, the connecting plate being disposed on the same side of a plurality of separation plates, the connecting plate being provided with a sliding groove; a connecting rod corresponding to each separation plate, one end of the connecting rod being vertically connected to a second connecting rod, the second connecting rod being connected to one end of the connecting rod, the second connecting rod being slidably disposed in the sliding groove, the other end of the connecting rod being connected to the corresponding separation plate; a second driving rod, the second driving rod and the first driving rod being switchably connected to the telescopic end of the second driving member, the second driving rod being arranged along an axial direction parallel to the primary air channel, at least a portion of the second driving rod penetrating into the primary air channel; and a blunt body connected to the second driving rod.

[0011] In some embodiments, the inner wall of the primary air duct is provided with mounting holes for mounting a rotating shaft; the air supply device further includes a locking assembly for locking the rotating shaft, the locking assembly and the rotating shaft being configured one-to-one, the locking assembly including: a first locking member disposed between the side wall of the mounting hole and the rotating shaft, the first locking member being deformable under temperature; a second locking member disposed between the first locking member and the rotating shaft; the second locking member including: a locking sleeve disposed between the first locking member and the rotating shaft, the locking sleeve having a plurality of radially penetrating locking channels; a locking block slidably disposed within the corresponding locking channel; and an elastic element disposed between the locking block and the locking sleeve.

[0012] In some embodiments, the air supply device further includes: a secondary air duct, spaced apart and sleeved outside the primary air duct, wherein a secondary fan is installed inside the secondary air duct; and an oxygen-enriching duct, disposed between the secondary air duct and the primary air duct, wherein an oxygen-enriching regulating valve is installed inside the oxygen-enriching duct.

[0013] In a second aspect, this application also provides a control method for a full-load multi-coal type modulated oxygen-enriched combustion system. The control method includes: identifying the type of coal used in the furnace; identifying the load of the furnace under the condition that the coal is a low-volatile coal type; if the load of the furnace is a first threshold, closing the first regulating valve, the second regulating valve, and the third regulating valve of the flue gas circulation pipeline, and controlling the switching device to operate, wherein the first inlet and the second outlet of the switching device are connected; if the load of the furnace is a second threshold, and the second threshold is less than the first threshold, opening the first regulating valve and the second regulating valve of the flue gas circulation pipeline, and closing the third regulating valve. A valve controls the operation of the switching device, with the first inlet and the second outlet of the switching device connected. If the load of the furnace is a third threshold, which is less than the second threshold, the first regulating valve of the flue gas circulation pipeline is opened, and the second regulating valve and the third regulating valve are closed, controlling the operation of the switching device, with the first inlet and the first outlet of the switching device connected. If the load of the furnace is a fourth threshold, which is less than the second threshold, the second regulating valve of the flue gas circulation pipeline is opened, and the first regulating valve and the third regulating valve are closed, controlling the operation of the switching device, with the first inlet and the first outlet of the switching device connected.

[0014] In some implementations, the control method further includes: under the condition that the coal type is a high-volatile coal type, confirming the load of the furnace; if the load of the furnace is a fifth threshold, closing the first regulating valve, the second regulating valve, and the third regulating valve of the flue gas circulation pipeline, controlling the switching device to operate, and connecting the first inlet and the second outlet of the switching device; if the load of the furnace is a sixth threshold, and the sixth threshold is less than the fifth threshold, closing the first regulating valve of the flue gas circulation pipeline, opening the second regulating valve and the third regulating valve, controlling the switching device to operate, and connecting the first inlet and the first outlet of the switching device; if the load of the furnace is a seventh threshold, and the seventh threshold is less than the sixth threshold, opening the second regulating valve of the flue gas circulation pipeline, closing the first regulating valve and the third regulating valve, controlling the switching device to operate, and connecting the first inlet and the first outlet of the switching device.

[0015] The full-load multi-coal type modulated oxygen-enriched combustion system and its control method provided in this application, through the combination of pipeline switching, pulverized coal concentration and separation, localized precise oxygen enrichment supply, and multi-element flue gas recirculation technology, can achieve both stable combustion and low NOx emissions under ultra-low load (10%-15%) conditions for multiple coal types (lignite, bituminous coal, lean coal, and anthracite). Compared with traditional solutions, the oxygen enrichment technology in this application is highly economical, has low investment and operating costs, a wide adjustable range of concentration ratios, high utilization rate of recirculated flue gas, and significant effects on stable combustion and NOx reduction. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the layout of a full-load multi-coal type modulated oxygen-enriched combustion system according to one or more embodiments of this application is shown; Figure 2 A schematic diagram of the arrangement of the pulverized coal conveying assembly X is shown; Figure 3 A schematic diagram of the separation device 5 in some embodiments is shown; Figure 4 It shows Figure 3 A schematic diagram of the layout of the air inlet duct 53; Figure 5 It shows Figure 4 A top-down view; Figure 6 It shows Figure 5A schematic diagram of the AA cross-section; Figure 7 A schematic diagram of the air supply device 6 in some embodiments is shown; Figure 8 It shows Figure 7 A side view diagram; Figure 9 It shows Figure 8 BB cross-sectional diagram; Figure 10 It shows Figure 9 Enlarged view of point C; Figure 11 A schematic diagram of the assembly of the rotating shaft 622 and the primary air duct 61 is shown; Figure 12 It shows Figure 11 An explosion diagram; Figure 13 An assembly diagram of the locking component 64 is shown; Figure 14 It shows Figure 13 A schematic diagram of the structure of the second locking element 642; Figure 15 It shows Figure 14 An explosion diagram; Figure 16 A schematic diagram of the mechanical transmission of the air supply device 6 is shown; Figure 17 A schematic diagram of the structure of the blunt body 65 is shown.

[0018] Explanation of reference numerals in the attached figures: X. Pulverized coal conveying components; 1. Primary air-powder piping; 2. Main flue gas pipe; 3. Flue gas recirculation pipeline; 31. First flue gas pipeline; 32. Second flue gas pipeline; 33. Third flue gas pipeline; 34. First fan; 35. First regulating valve; 36. Second fan; 37. Second regulating valve; 38. Third fan; 39. Third regulating valve; 4. Switching device; 41. Valve body; 42. First branch pipe; 43. Second branch pipe; 44. Third branch pipe; 45. Valve plate; 5. Separation device; 51. Housing; 52. Cyclone separator blades; 53. Air inlet duct; 54. Slider; 55. Adjustment port; 56. Adjustment rod; 57. First enclosure plate; 58. Second enclosure plate; 59. First sealing plate; 510. Driving component; 511. Separation motor; 512. Drive screw; 513. Drive block; 514. Guide rod; 6. Air supply device; 61. Primary air duct; 611. First connecting port; 612. Second connecting port; 613. Third connecting port; 614. First guide groove; 615. Mounting hole; 6151. Mounting groove; 616. Third enclosure plate; 617. Second sealing plate; 618. Second guide groove; 62. Separation window; 621. Separation plate; 622. Rotating shaft; 63. Adjustment assembly; 631. Second driving component; 632. First driving rod; 633. Connecting plate; 6331. Slide groove; 634. First connecting rod; 635. Second connecting rod; 636. Second driving rod; 37. First electromagnet; 638. Second electromagnet; 639. Third drive rod; 6310. Third connecting rod; 64. Locking assembly; 641. First locking element; 6411. Mounting protrusion; 642. Second locking element; 6421. Locking sleeve; 6422. Locking block; 6423. Elastic element; 6424. Locking channel; 6425. Annular protrusion; 6426. Limiting protrusion; 65. Blunt body; 651. Heat exchange chamber; 652. Turbulence column; 66. Secondary air channel; 67. Oxygen-enriched channel; 68. Secondary fan; 69. Oxygen-enriched regulating valve; 610. Support base; 7. Furnace; 8. Economizer; 9. SCR reactor; 10. Air preheater; 11. Dust collector; 12. Desulfurizer; 13. Chimney; 14. Burner. Detailed Implementation

[0019] To enable those skilled in the art to more clearly understand this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0020] The design concept of the full-load multi-coal type modulated oxygen-enriched combustion system provided in this application is as follows: according to the load operation of the furnace 7, the circulating flue gas generated by the combustion system at different temperatures is mixed with the primary air and pulverized coal during transportation and preheated, so as to promote the release of some volatiles and create favorable conditions for subsequent ignition; at the same time, the low oxygen characteristics and heat absorption effect of the circulating flue gas can effectively suppress the peak combustion temperature and reduce NOx generation, so as to ensure low-NOx and stable combustion of coal with different volatile contents under low load conditions and enhance the coal type adaptability of the combustion system.

[0021] Figure 1 A schematic diagram of the layout of a full-load multi-coal type modulated oxygen-enriched combustion system according to one or more embodiments of this application is shown. (In conjunction with...) Figure 1The combustion system provided in this application includes a burner 14, a furnace 7, an economizer 8, and a dust collector 11, which are connected in sequence and work together. The burner 14 fully mixes fuel (oil, gas, pulverized coal, garbage, etc.) and combustion air, injects it into the furnace, and stably ignites and burns it. The furnace 7 is used for fuel combustion, the economizer 8 is used for heat recovery, and the dust collector 11 is used for pollutant control. For ease of description, the flue gas produced by the furnace 7 is defined as high-temperature flue gas (700℃-800℃), the flue gas generated by the economizer 8 is defined as medium-temperature flue gas (300℃-400℃), and the flue gas generated by the dust collector 11 is defined as low-temperature flue gas (130℃-180℃).

[0022] In addition to the furnace 7, economizer 8, and dust collector 11 mentioned above, the combustion system also includes an SCR (Selective Catalytic Reduction) reactor, an air preheater 10, a desulfurizer 12, and a chimney 13. Along the flue gas flow direction, the SCR reactor 9 and air preheater 10 are sequentially arranged between the economizer 8 and the dust collector 11, while the desulfurizer 12 and chimney 13 are sequentially arranged downstream of the dust collector 11. The reactor is located immediately after the economizer 8 and before the air preheater 10. Flue gas from the economizer 8 enters the SCR reactor 9. The reducing agent (usually ammonia or urea solution) in the SCR reactor 9 is sprayed, evaporated, and uniformly mixed with the flue gas. The mixed gas passes through a reaction layer filled with catalyst. Under the action of the catalyst, nitrogen oxides (NOx) in the flue gas are reduced. x It undergoes a selective reduction reaction with ammonia (NH3) to produce harmless nitrogen gas (N2) and water vapor (H2O), thus efficiently removing nitrogen oxides (NOx). x The air preheater 10 is a key environmental protection device for controlling acid rain and photochemical pollution. Located after the SCR reactor 9 and before the dust collector 11, the air preheater 10 further reduces the temperature of the flue gas after SCR denitrification, creating favorable temperature conditions for subsequent dust removal and desulfurization. The dust collector 11 is located after the air preheater 10 and before the desulfurizer 12 to remove dust from the flue gas and protect the downstream desulfurizer 12. The desulfurizer 12 is located after the dust collector 11 and before the chimney 13 to efficiently remove sulfur dioxide from the flue gas, making it a key device for controlling acid rain. The chimney 13 is the endpoint of the entire flue gas treatment process. Utilizing high potential energy, the chimney 13 discharges flue gas that meets ultra-low emission standards (low dust, low sulfur, low nitrogen) into the upper atmosphere for final dilution and diffusion.

[0023] Combination Figure 1 The combustion system also includes a pulverized coal conveying assembly X. Figure 2 A schematic diagram of the arrangement of the pulverized coal conveying assembly X is shown, combined with... Figure 1 as well as Figure 2The pulverized coal conveying assembly X includes a flue gas circulation pipeline 3, a primary air-pulverized coal pipeline 1, a separation device 5, and an air supply device 6. The flue gas circulation pipeline 3 includes a first flue gas pipeline 31, a second flue gas pipeline 32, and a third flue gas pipeline 33. The inlet of the first flue gas pipeline 31 is connected to the furnace 7. A first fan 34 and a first regulating valve 35 are installed on the first flue gas pipeline 31. By controlling the start of the first fan 34, the high-temperature flue gas generated in the furnace 7 can be drawn in. By controlling the first regulating valve 35, the flow rate of the high-temperature flue gas and the on / off state of the first flue gas pipeline 31 can be controlled. The inlet of the second flue gas pipeline 32 is connected to the outlet of the economizer 8. A second fan 36 and a second regulating valve 37 are installed on the gas pipeline 32. By controlling the start of the second fan 36, the medium-temperature flue gas generated by the economizer 8 can be drawn in. By controlling the second regulating valve 37, the flow rate of the medium-temperature flue gas and the on / off state of the second flue gas pipeline 32 can be controlled. The inlet of the third flue gas pipeline 33 is connected to the outlet of the dust collector 11. A third fan 38 and a third regulating valve 39 are installed on the third flue gas pipeline 33. By controlling the start of the third fan 38, the low-temperature flue gas generated by the dust collector 11 can be drawn in. By controlling the third regulating valve 39, the flow rate of the low-temperature flue gas and the on / off state of the third flue gas pipeline 33 can be controlled. In addition, the temperature of the recirculated flue gas can be changed by opening and closing the first regulating valve 35, the second regulating valve 37, and / or the third regulating valve 39 according to the degree of non-combustibility of the coal used in the coal-fired boiler. The flue gas circulation fan is controlled according to the actual load of the coal-fired boiler to change the circulating flue gas volume. For example, the first regulating valve 35, the second regulating valve 37, and the third regulating valve 39 can be solenoid valves, so as to be able to remotely receive commands. Combination Figure 2 The pulverized coal conveying assembly also includes a primary air-coal pipeline 1, which is used to input pulverized coal mixed with primary air. The first flue gas pipeline 31, the second flue gas pipeline 32, and the third flue gas pipeline 33 converge into a main flue gas pipe 2, which is connected to the primary air-coal pipeline 1. This allows the flue gas drawn by the first flue gas pipeline 31, the second flue gas pipeline 32, and / or the third flue gas pipeline 33 to combine with the air conveyed by the primary air-coal pipeline 1, forming primary air-coal flow streams at different temperatures. During the circulating flue gas conveying process, waste heat is used to preheat and decompose the pulverized coal, causing some volatiles to precipitate prematurely, converting heterogeneous combustion into homogeneous combustion for stable combustion. Furthermore, the low oxygen content of the circulating flue gas prevents the precipitated volatiles from prematurely igniting in the pulverized coal pipeline. Upon entering the furnace 7, it also absorbs additional heat generated by combustion, reducing the peak combustion temperature and thus reducing NOx formation during combustion.

[0024] Combination Figure 2The pulverized coal conveying assembly also includes a switching device 4, which has a first inlet, a first outlet, and a second outlet. The first inlet of the switching device 4 is switchably connected to one of the first and second outlets; that is, when the first inlet is connected to the first outlet, the first inlet and the second outlet are disconnected, and when the first inlet is connected to the second outlet, the first inlet and the first outlet are disconnected. The first inlet is connected to the outlets of the first flue gas pipeline 31, the second flue gas pipeline 32, the third flue gas pipeline 33, and the primary air-coal pipeline 1. In other words, the primary air-coal flow at different temperatures can be conveyed through one of the first and second outlets via the switching device 4.

[0025] Combination Figure 2 In some embodiments, the switching device 4 includes a valve body 41, a first branch pipe 42, a second branch pipe 43, a third branch pipe 44, and a valve plate 45, wherein: the first branch pipe 42, the second branch pipe 43, and the third branch pipe 44 are respectively connected to the periphery of the valve body 41 at intervals; the end of the first branch pipe 42 away from the valve body 41 is configured as a first inlet; the end of the second branch pipe 43 away from the valve body 41 is configured as a first outlet; and the end of the third branch pipe 44 away from the valve body 41 is configured as a second outlet; the valve body 41 is provided with a first port communicating with the first branch pipe 42, a second port communicating with the second branch pipe 43, and a third port communicating with a third support; the valve plate 45 is located inside the valve body 41, the valve plate 45 is rotatably connected to the valve body 41, and is located between the second port and the third port; the valve plate 45 can be controllably sealed one of the second port and the third port. When it is necessary to switch the primary air-coal flow path, the valve plate 45 can be rotated to cover one of the second and third ports, thereby allowing the first inlet to be switched to connect with one of the first and second outlets. In specific implementations, the position of the valve plate 45 is adjusted according to the working load of the furnace 7, thereby changing the flow direction of the primary air-coal flow. Exemplarily, the valve plate 45 can be driven to rotate by a motor, or it can be manually controlled; this application does not limit this.

[0026] Combination Figure 2 The separation device 5 has a second inlet, a third outlet, and a fourth outlet. The second inlet of the separation device 5 is connected to the third and fourth outlets, and the second inlet of the separation device 5 is connected to the first outlet of the switching device 4. The gas flow concentration discharged from the third outlet is greater than that discharged from the fourth outlet. After being processed by the separation device 5, the primary air-powder gas flow discharged from the first outlet generates two gas flows with different concentrations. That is, the gas flow discharged from the third outlet is a dense phase coal powder gas flow, and the gas flow discharged from the fourth outlet is a dilute phase coal powder gas flow, thereby achieving the separation of dense and dilute coal powder gas flows.

[0027] Combination Figure 2In some embodiments, the separation device 5 can be a cyclone separator, which includes a housing 51 and cyclone separation blades 52 disposed inside the housing 51. A second inlet is provided on the circumferential surface of the housing 51, a third outlet is provided at one axial end of the housing 51, and a fourth outlet is provided at the other axial end of the housing 51. The primary air-powder gas flow discharged through the first outlet is injected into the housing 51 through the second inlet. Under the action of the cyclone separation blades 52, the primary air-powder or primary air-powder mixed with flue gas flows along the circumference of the cyclone separation blades 52 to form an airflow. The heavier air-powder carried in the airflow is separated between the cyclone separation blades 52 and the housing 51 and deposited at one axial end of the housing 51 and discharged from the third outlet to form a first airflow with a higher concentration, namely, a dense phase coal powder airflow. The lighter air-powder in the airflow is discharged from the fourth outlet at the other axial end of the housing 51 to form a second airflow with a lower concentration, namely, a light phase coal powder airflow, thereby realizing the separation of the concentration and lightness of the coal powder airflow.

[0028] Figure 3 A schematic diagram of the separation device 5 in some embodiments is shown, in conjunction with... Figure 3 In some embodiments, the separation device 5 further includes an air inlet duct 53, which is connected to a second inlet. The primary air-dust airflow discharged through the first outlet is transported into the housing 51 via the air inlet duct 53. The air inlet duct 53 is tangential to the circumferential surface of the housing 51, thereby enabling the primary air-dust airflow to obtain an initial velocity tangential to the cylinder wall when entering the housing 51. This converts the linear motion kinetic energy of the airflow into rotational motion kinetic energy around the axis, thereby increasing the centrifugal force of the airflow. Dust particles (especially larger and denser particles) are subjected to a huge centrifugal force and are thrown at high speed towards the cylinder wall, and deposited at one axial end of the housing 51. Meanwhile, smaller and less dense particles form a low-pressure rising vortex in the central region of the housing 51 and are finally discharged from the other axial end of the housing 51.

[0029] In some embodiments, at least a portion of the cross-sectional area of ​​the air inlet duct 53 is adjustable. This configuration allows for adjustment of the cross-sectional area of ​​at least a portion of the air inlet duct 53 according to different operating conditions to maintain optimal separation efficiency. For example, when the air volume increases, the inlet cross-section of at least a portion of the air inlet duct 53 is increased to prevent excessively high air velocity; when the air volume decreases, the cross-section of at least a portion of the air inlet duct 53 is decreased to prevent excessively low inlet air velocity, thereby maintaining a constant and optimal inlet air velocity and ensuring separation performance.

[0030] Figure 4 It shows Figure 3 A schematic diagram of the layout of the air inlet duct 53. (Combined with...) Figure 4In some embodiments, the separation device 5 further includes a slider 54, at least a portion of which is slidably disposed within the air inlet duct 53. By adjusting the position of the slider 54 within the air inlet duct 53, the cross-sectional area of ​​a certain point in the air inlet duct 53 can be changed, thereby adjusting the inlet air velocity and ensuring the separation effect.

[0031] Figure 5 It shows Figure 4 A top-down view. Figure 6 It shows Figure 5 A schematic diagram of the AA cross section, combined with Figure 6 In some embodiments, the side wall of the air inlet duct 53 is provided with an adjustment port 55, at least part of the slider 54 is slidably disposed in the adjustment port 55, and an adjustment rod 56 is connected to the outside of the slider 54. By controlling the movement of the adjustment rod 56, the slider 54 can be driven to move back and forth in the adjustment port 55 to adjust the position of the slider 54 in the air inlet duct 53.

[0032] Combination Figure 6 In some embodiments, a first surrounding plate 57 is provided on the inner side of the sidewall of the air inlet duct 53, and the first surrounding plate 57 is arranged around the edge of the adjustment port 55; while a second surrounding plate 58 is provided on the outer side of the outer side of the air inlet duct 53, and the second surrounding plate 58 is located at the edge of the adjustment port 55. The first surrounding plate 57, the adjustment port 55, and the second surrounding plate 58 form a sliding channel, and the slider 54 is slidably disposed within the sliding channel. This arrangement can restrict the movement direction of the slider 54. In addition, to avoid leakage, at least one sealing ring can be provided between the sliding plate and the inner wall of the sliding channel. It should be noted that the first surrounding plate 57 and the second surrounding plate 58 can coexist, or only one of them can be present; this application does not impose any restrictions on this.

[0033] Combination Figure 6 In some embodiments, the separation device 5 further includes a first sealing plate 59, which covers the outer side of the second enclosure plate 58. That is, the first sealing plate 59 covers the outer end of the sliding channel to seal the sliding channel and prevent dust leakage in the flue gas to a certain extent. The first sealing plate 59, the second enclosure plate 58, the first enclosure plate 57, and the air inlet duct 53 can be integrally formed or connected by bolts. This application does not limit this.

[0034] Combination Figure 4 In some embodiments, the separating device 5 further includes a first driving member 510, which has a reciprocating telescopic portion, to which the slider 54 is connected. This arrangement allows for automated control of the slider 54's movement within the sliding channel. Of course, in other embodiments, the slider 54 can also be manually adjusted, and this application does not impose any limitations on this.

[0035] Combination Figure 4 In some embodiments, the first driving component 510 includes a separating motor 511, a driving screw 512, and a driving block 513. The separating motor 511 is connected to either the housing 51 or the air inlet pipe. One end of the driving screw 512 is connected to the separating motor 511, and the other end is connected to a baffle. The driving block 513 is threaded to the driving screw 512 and is connected to the slider 54. When it is necessary to adjust the cross-sectional area of ​​the air inlet pipe 53, the separating motor 511 is started. The separating motor 511 drives the driving screw 512 to rotate synchronously, which in turn drives the slider 54 to move along the axial direction of the driving screw 512. This allows the slider 54 to be adjusted within the air inlet pipe 53, changing the cross-sectional area of ​​a certain point in the air inlet pipe 53, thereby adjusting the inlet air velocity and ensuring the separation effect.

[0036] Combination Figure 4 In some embodiments, the first driving member 510 further includes two guide rods 514, one end of which is connected to a baffle, and the separation motor 511 is connected to the other end of the two guide rods 514. The two guide rods 514 slide through the driving block 513. When the slider 54 is moved by the separation motor 511, the driving block 513 slides on the guide rods 514 to guide the movement of the slider 54. The two guide rods 514 also allow the separation motor 511 to be fixedly mounted on the outside of the air inlet duct 53. Exemplarily, the two guide rods 514 are arranged opposite each other on both sides of the driving screw 512. Of course, in other embodiments, the separation motor 511 can also be connected to the outer peripheral surface of the housing 51; this application does not limit this.

[0037] Combination Figure 4 In some embodiments, the first driving member 510 further includes a connecting block 515, which connects to the driving block 513. The adjusting rod 56 is connected to the connecting block 515 to connect the slider 54 to the driving block 513. Exemplarily, two adjusting rods 56 are also provided, and the connecting block 515 is disposed between the two adjusting rods 56 and the driving block 513.

[0038] Combination Figure 2 The pulverized coal conveying assembly X also includes an air supply device 6, which includes a primary air channel 61. The primary air channel 61 has an air supply end and an air outlet end. The air supply end of the primary air channel 61 is connected to the second outlet of the switching device 4, the third outlet of the separation device 5, and the fourth outlet, respectively. The air outlet end of the primary air channel 61 is connected to the furnace 7. The pulverized coal conveyed through the second outlet of the switching device 4 can be directly conveyed to the furnace 7 through the primary air channel 61 without being processed by the separation device 5. Alternatively, the pulverized coal conveyed through the first outlet of the switching device 4 can be further separated by the separation device 5 to form a dense phase pulverized coal airflow and a light phase pulverized coal airflow, which are then conveyed to the furnace 7 through the primary air channel 61.

[0039] Figure 7 A schematic diagram of the air supply device 6 in some embodiments is shown. (Combined with...) Figure 7 In some embodiments, the primary air duct 61 is horizontal in direction, with its two ends being an air supply end and an air outlet end, respectively. The air supply end is provided with a first connecting port 611, a second connecting port 612, and a third connecting port 613, which are successively lower in height. The first connecting port 611 is connected to the third outlet, the second connecting port 612 is connected to the second outlet, and the third connecting port 613 is connected to the fourth outlet. That is, the dense pulverized coal airflow with the highest concentration is injected into the primary air duct 61 through the first connecting port 611, the pulverized coal airflow with the next highest concentration is injected into the primary air duct 61 through the second connecting port 612, and the pulverized coal airflow with the lowest concentration is injected into the primary air duct 61 through the third connecting port 613, thereby forming a denser pulverized coal airflow at the top and a less dense pulverized coal airflow at the bottom within the primary air duct 61. For example, the primary air duct 61 is manufactured from a cylindrical pipe, with the aforementioned first connecting port 611, second connecting port 612, and third connecting port 613 sequentially opened vertically at one end along its axial direction, while the other end is open to allow pulverized coal to be smoothly injected into the furnace 7. Furthermore, the first connecting port 611, second connecting port 612, and third connecting port 613 can be staggered to accommodate the relevant pipe arrangement.

[0040] Figure 8 It shows Figure 7 Side view diagram, Figure 9 It shows Figure 8 A schematic diagram of the BB cross-section. Combined with... Figure 6 as well as Figure 9 In some embodiments, the air supply device 6 further includes a separation window 62, which is disposed within the primary air channel 61. The separation window 62 includes multiple separation plates 621 spaced apart along the axial direction of the primary air channel 61. The multiple separation plates 621 are rotatably connected to the sidewall of the primary air channel 61 and are inclined within the primary air channel 61, with the end of the separation plate 621 near the air outlet higher than the end near the air supply end. This arrangement allows the centrifugal force of the multiple separation plates 621 in the separation window 62 to further divide the pulverized coal airflow within the primary air channel 61 into an upper concentrated zone and a lower depleted zone, thus facilitating pulverized coal combustion. Furthermore, since the separation plates 621 are rotatably connected to the sidewall of the primary air channel 61, the inclination angle of the separation plates 621 within the primary air channel 61 is adjustable. This allows for adjustment of the inclination angle of the separation plates 621 according to the actual combustion conditions, flexibly adjusting the concentration-to-depletion ratio of the pulverized coal airflow to achieve efficient pulverized coal concentration-to-depletion separation and improve combustion efficiency. For example, both ends of each separation piece 621 are rotatably connected to the side wall of the primary air duct 61 via a rotating shaft 622.

[0041] Figure 10 It shows Figure 9The enlarged diagram at point C, combined with Figure 9 as well as Figure 10 In some embodiments, to achieve angle adjustment of the separating plate 621, the air supply device 6 of this application further includes an adjustment assembly 63 for driving the separating plate 621 to rotate. The adjustment assembly 63 includes a second driving member 631, a first driving rod 632, a connecting plate 633, and a first connecting rod 634. The second driving member 631 has a telescopic end that reciprocates along an axial direction parallel to the primary air channel 61. The first driving rod 632 is connected to the telescopic end of the second driving member 631 and is arranged along an axial direction parallel to the primary air channel 61. At least a portion of the first driving rod 632... It is inserted into the primary air duct 61; the connecting plate 633 is set in the primary air duct 61, the connecting plate 633 is connected to the first drive rod 632, the connecting plate 633 is set on the same side of multiple separation plates 621, and the connecting plate 633 is provided with a sliding groove 6331; the first connecting rod 634 and the separation plate 621 are arranged one-to-one, one end of the first connecting rod 634 is vertically connected to the second connecting rod 635, the second connecting rod 635 is connected to one end of the first connecting rod 634, the second connecting rod 635 is slidably set in the sliding groove 6331, and the other end of the first connecting rod 634 is connected to the corresponding separation plate 621. When it is necessary to adjust the angle of the separating plate 621, the second driving member 631 is controlled to move. The telescopic end of the second driving member 631 extends and retracts synchronously, thereby driving the first driving rod 632 and the connecting plate 633 to extend and retract synchronously. This, in turn, drives the second connecting rod 635 to move in the slide groove 6331. The second connecting rod then drives the separating plate 621 to rotate around the rotating shaft 622, thereby realizing the angle adjustment of the separating plate 621.

[0042] In specific implementation, the second driving member 631 can be an electric push rod, which can be installed on the outside of the air inlet end of the primary air channel 61 through the support base 610. The push rod of the second driving member 631 is configured as a telescopic part.

[0043] Combination Figure 10 In some embodiments, the inner wall of the primary air channel 61 is provided with a first guide groove 614, and at least a portion of the first drive rod 632 is adapted to slide within the first guide groove 614. The first guide groove 614 is axially parallel to the primary air channel 61, with one end of the first guide groove 614 open towards the air inlet and the other end closed towards the air outlet, so that the first drive rod 632 can enter from the open end of the first guide groove 614 and be limited by the closed end of the first guide groove 614.

[0044] Combination Figure 10In some embodiments, the first drive rod 632 and the connecting plate 633 are arranged in parallel and can be connected by a transition plate so that the first drive rod 632 and the connecting plate 633 can move synchronously along an axial direction parallel to the primary air duct 61. In addition, the groove 6331 on the connecting plate 633 can be arranged vertically, and the end of the second connecting rod is adapted to be disposed in the groove 6331 on the connecting plate 633. The second connecting rod, the first connecting rod 634, and the separation plate 621 can be an integral structure or can be detachably connected by bolts or other components. This application does not limit this.

[0045] In the above implementation, the separation plate 621 is driven by one side. In other embodiments, the separation plate 621 can also be driven by both sides by adding a set of mutually cooperating second driving component 631, first driving rod 632, connecting plate 633, and first connecting rod 634. This application will not elaborate on this.

[0046] In actual implementation, since the air powder is input from the inlet end of the primary air duct and output from the outlet end of the primary air duct, the air powder will form an airflow in the primary air duct. During the flow of the airflow inside the primary air duct, it may drive the separating plate 621 to rotate. Based on this, the air supply device 6 provided in this application also includes a locking component 64 for locking the rotating shaft 622. The locking component 64 and the rotating shaft 622 are arranged in a one-to-one correspondence. After the angle of the separating plate 621 is adjusted to the position, the rotating shaft 622 can be locked by the locking component 64, thereby fixing the separating plate 621 in the primary air duct.

[0047] Figure 11 A schematic diagram of the assembly of the rotating shaft 622 and the primary air duct 61 is shown. Figure 12 It shows Figure 11 An explosion diagram. Figure 13 An assembly diagram of the locking component 64 is shown. (Combined with...) Figures 11-13In some embodiments, the inner wall of the primary air duct 61 is provided with a mounting hole 615 for mounting a rotating shaft 622. The locking assembly 64 includes a first locking member 641, which is disposed between the side wall of the mounting hole 615 and the rotating shaft 622. The first locking member 641 can deform under the action of temperature. In specific implementation, the first locking member 641 can be a shape memory alloy. When adjusting the angle of the separating plate 621, the entire combustion system is not running. Therefore, the temperature inside the primary air passage 61 is at room temperature, and the first locking member 641 does not deform. Therefore, the first locking member 641 will not exert a force on the rotating shaft 622, and the adjusting component 63 can drive the separating plate 621 to rotate around the rotating shaft 622. During the operation of the combustion system, the air and coal contain flue gas at a certain temperature. Therefore, the primary air passage 61 is in an environment with a certain temperature, which is approximately 150~600℃. The first locking member 641 deforms in the high temperature environment to increase its volume, thereby causing the first locking member 641 to shift in the direction relative to the rotating shaft 622 to lock the rotating shaft 622, thereby fixing the separating plate 621 inside the primary air passage. For example, the first locking member 641 is a high-temperature alloy bimetallic material, such as a nickel-chromium high-temperature bimetallic material or an iron-chromium-aluminum composite bimetallic material. The first locking member 641 is an annular component that can deform at a temperature of 150~600°C to meet the high-temperature environment of the primary air duct 61.

[0048] Combination Figure 12 as well as Figure 13 In some embodiments, the first locking member 641 is a columnar structure when it is not deformed. Multiple mounting protrusions 6411 are provided at intervals on the outer periphery of the first locking member 641, and mounting grooves 6151 are provided on the inner wall of the mounting hole 615. The multiple protrusions are disposed in the corresponding grooves so that the first locking member 641 engages with the inner wall of the mounting hole 615 so that the first locking member 641 is stably assembled in the mounting hole 615.

[0049] Figure 14 It shows Figure 13 A schematic diagram of the structure of the second locking element 642. Figure 15 It shows Figure 14 An explosion diagram, combined with the image Figures 13-15In some embodiments, the locking assembly 64 further includes a second locking member 642, which is disposed between the first locking member 641 and the rotating shaft 622. The second locking member 642 includes a locking sleeve 6421, a locking block 6422, and an elastic member 6423. The locking sleeve 6421 is sleeved between the first locking member 641 and the rotating shaft 622. The locking sleeve 6421 is provided with a plurality of radially penetrating locking channels 6424. The locking block 6422 is slidably disposed in the corresponding locking channel 6424. The elastic member 6423 is disposed between the locking block 6422 and the locking sleeve 6421. At room temperature, under the action of the elastic element 6423, the inner ends of the multiple locking blocks 6422 do not protrude from the inner side of the corresponding locking channel 6424, and the rotating shaft 622 can rotate within the locking sleeve 6421. At high temperature, due to the deformation and expansion of the first locking element 641, the first locking element 641 drives the multiple locking blocks 6422 to move within the corresponding locking channel 6424. The inner ends of the multiple locking blocks 6422 protrude from the inner side of the corresponding locking channel 6424 and abut against the circumferential surface of the rotating shaft 622. The locking blocks 6422 make hard contact with the rotating shaft 622 to lock the rotating shaft 622, while compressing the elastic element 6423 to store energy for the return of the locking blocks 6422 at room temperature. For example, the locking sleeve 6421 is provided with three radially penetrating locking channels 6424, and the three locking channels 6424 are spaced apart circumferentially around the locking sleeve 6421. In other embodiments, there may be two or four locking channels 6424, and this application does not limit this.

[0050] Combination Figure 14 as well as Figure 15 In some embodiments, an annular protrusion 6425 is provided in the middle of the outer peripheral surface of the locking sleeve 6421, and a locking channel 6424 extends from the outer peripheral surface of the annular protrusion 6425 to the inner peripheral surface of the locking sleeve 6421. The locking channel 6424 is located at the bottom opening of the portion of the annular protrusion 6425. A limiting protrusion 6426 is provided at the bottom of the locking block 6422. The limiting protrusion 6426 protrudes through the bottom opening of the annular protrusion 6425. One end of the elastic member 6423 is connected to the limiting protrusion 6426, and the other end of the elastic member 6423 abuts against the outer peripheral surface of the locking sleeve 6421 to realize the assembly of the elastic member 6423.

[0051] Combination Figure 10 In some embodiments, a third surrounding plate 616 is provided inside the mounting hole 615, extending into the mounting hole 615, and the rotating shaft 622 movably passes through the third surrounding plate 616. By providing the third surrounding plate 616, the deformation range of the first locking member 641 can be limited, so that the first locking member 641 can only deform radially, thereby efficiently driving the locking block 6422.

[0052] Combination Figure 12 as well as Figure 13 In some embodiments, the outer end of the mounting hole 615 is open and sealed by a removable second sealing plate 617. This arrangement facilitates the assembly of the first locking member 641 and the second locking member 642. After the first locking member 641 and the second locking member 642 are assembled in place, the outer end of the mounting hole is sealed by the second sealing plate 617, which limits the deformation range of the first locking member 641, ensuring that the first locking member 641 can only deform radially, thereby efficiently driving the two locking blocks 6422.

[0053] Combination Figure 2 as well as Figure 6 In some embodiments, the air supply device 6 further includes a blunt body 65 disposed within the primary air channel 61. Along the axial direction of the primary air channel 61, the blunt body 65 is positioned between the separation window 62 and the air supply end. The thickness of the end of the blunt body 65 facing the air supply end is less than the thickness of the end facing the air outlet end. The distance from the blunt body 65 to the side facing the air outlet end is adjustable. With this configuration, the pulverized coal airflow can pass through the blunt body 65 and be delivered into the furnace 7 to form a high-temperature recirculation zone. Furthermore, since the distance from the blunt body 65 to the side facing the air outlet end is adjustable, the size of the high-temperature recirculation zone can be changed by altering the position of the blunt body 65, thereby enhancing the stable combustion effect. For details, please refer to the relevant description of the control method below. For example, the blunt body 65 is arranged in a conical shape.

[0054] Figure 16 A schematic diagram of the mechanical transmission of the air supply device 6 is shown. (Combined with...) Figure 7 as well as Figure 16 In some embodiments, the air supply device 6 further includes a second drive rod 636. The second drive rod 636 and the first drive rod 632 are switchably connected to the telescopic end of the second drive member 631. The second drive rod 636 is arranged axially parallel to the primary air channel 61, and at least a portion of the second drive rod 636 extends into the primary air channel 61. The blunt body 65 is connected to the second drive rod 636. When it is necessary to adjust the position of the blunt body 65, the second drive rod 636 is switched to the telescopic end of the second drive member 631, and then the second drive member 631 is activated. The telescopic end of the second drive member 631 moves back and forth, thereby driving the second drive rod 636 and the blunt body 65 to move synchronously, so as to achieve the technical effect of adjustable position of the blunt body 65.

[0055] Combination Figure 16In some embodiments, in order to enable the second drive rod 636 and the first drive rod 632 to be switchably connected to the telescopic end of the second drive member 631, the adjustment component 63 of this application further includes a first electromagnet 637 and a second electromagnet 638. The first electromagnet 637 and the second electromagnet 638 are both connected to the telescopic end of the second drive member 631. The first electromagnet 637 is connected to the first drive rod 632, and the second electromagnet 638 is connected to the second drive rod 636. When the tilt angle of the separating plate 621 needs to be adjusted, the first electromagnet 637 is activated and the second electromagnet 638 is deactivated. The first electromagnet 637 is connected to the first drive rod 632, and the second electromagnet 638 is deactivated from the second drive rod 636. The second drive member 631 is used to drive the separating plate 621 to rotate to a suitable tilt angle. After the angle of the separating plate 621 is adjusted to the correct position, the first electromagnet 637 is deactivated and deactivated from the first drive rod 632. The second drive member 631 is then controlled to move its telescopic end to a suitable position, such as the position where the ends of the second electromagnet 638 and the second drive rod 636 are opposite each other. At this time, the second electromagnet 638 is activated and connected to the second drive rod 636. The second drive member 631 is used to drive the blunt body 65 to move to a suitable angle. For example, the telescopic end of the second driving member 631 is connected to a mounting block. A first electromagnet 637 and a second electromagnet 638 are arranged side-by-side on the mounting block. Both the first electromagnet 637 and the second electromagnet 638 are positioned outside the primary air duct 61 to prevent the high-temperature flue gas inside the primary air duct 61 from affecting the operation of the first electromagnet 637 and the second electromagnet 638. That is, this application can achieve the adjustment of the angle of the separating plate 621 and the position adjustment of the blunt body 65 through a single second driving member 631, thereby saving costs and effectively utilizing space.

[0056] Combination Figure 16 In some embodiments, the adjusting assembly 63 further includes a third drive rod 639 and a third connecting rod 6310. The third drive rod 639 and the second drive rod 636 are arranged opposite to each other. The third drive rod 639 is connected to the second drive rod 636 via the third connecting rod 6310. At least a portion of the third drive rod 6310 extends into the primary air duct 61. The other ends of the third drive rod 639 and the third connecting rod 637 are connected. That is, the second drive member 631 can simultaneously drive the second drive rod 636 and the third drive rod 639 to move back and forth, thereby driving the blunt body 65 to move, so that the force on the blunt body 65 is balanced.

[0057] Combination Figure 9 as well as Figure 16In some embodiments, the inner wall of the primary air duct 61 is provided with second guide grooves 618, at least a portion of the second drive rod 636 is slidably disposed in one of the second guide grooves 618, and at least a portion of the third drive rod 639 is slidably disposed in the other second guide groove 618, to guide the reciprocating movement of the second drive rod 636 and the third drive rod 639. Consistent with the first guide groove 614, the second guide groove 618 is axially parallel to the primary air duct 61, with one end of the second guide groove 618 open towards the air inlet and the other end of the second guide groove 618 closed, thereby allowing the second drive rod 636 and the third drive rod 639 to enter from the open end of the second guide groove 618 and be limited by the closed end of the second guide groove 618.

[0058] Figure 17 A schematic diagram of the blunt body 65 is shown. (Joint) Figure 17 In some embodiments, the blunt body 65 is hollow inside to form a preheating cavity 651. In addition, the blunt body 65 has an opening on the side facing the air outlet, that is, the side facing the furnace. The interior of the blunt body 65 is connected to the high-temperature zone of the furnace. The high temperature of the furnace is used to preheat the blunt body 65 to solve the problems of insufficient temperature in the recirculation zone and delayed ignition of pulverized coal under low load conditions. At the same time, the preheated blunt body 65 can preheat the passing pulverized coal airflow and reduce the ignition activation energy.

[0059] join Figure 17 In some embodiments, the circumferential surface of the blunt body 65 is connected to multiple turbulence columns 652. When pulverized coal forms an airflow within the primary air channel 61, the airflow causes the multiple turbulence columns 652 to vibrate, creating secondary micro-turbulence. This breaks the laminar flow state of the airflow, allowing the pulverized coal from the dense phase zone to be more evenly fed into the furnace. This ensures more thorough mixing of the pulverized coal with the air input from the secondary air channel 66 and the oxygen input from the oxygen-enriched channel 67, thereby improving combustion efficiency. For example, the diameter of the turbulence columns 652 can be 5-8 mm, and the height can be 10-15 mm.

[0060] In this application, the separator 621 is inclined at an angle α to the axial direction of the primary air channel 61, and the adjustment range of the angle α is 15°-45°; while the distance between the blunt body 65 and the air supply end of the primary air channel 61 is L, and the adjustment range of the distance L is 150mm-300mm.

[0061] Combination Figures 7-9In some embodiments, the air supply device 6 further includes a secondary air duct 66 and an oxygen-enriching duct 67. The secondary air duct 66 is spaced outside the primary air duct 61, and a secondary air fan 68 is installed inside the secondary air duct. The oxygen-enriching duct 67 is located between the secondary air duct 66 and the primary air duct 61, and an oxygen-enriching regulating valve 69 is installed inside the oxygen-enriching duct 67. Ambient air can be injected into the furnace 7 through the secondary air duct 66 to supplement oxygen to the airflow delivered to the outlet of the primary air duct 61, enhancing the mixing of pulverized coal and oxygen, forming local oxygen enrichment, increasing the average oxygen concentration to 22%~30%, and the oxygen concentration in the local area can reach up to 60%, which can significantly increase the flame temperature to promote complete combustion and improve combustion efficiency. Exemplarily, the blowing direction of the secondary air duct 66 is inclined towards the central axis of the primary air duct 61. The oxygen-enriched channel 67 is located on the rich side of the primary air channel 61, for example, on the upper side of the primary air channel 61 as shown in the figure. This configuration allows pure oxygen to be directly injected into the rich side of the primary air in the furnace 7, improving the ignition characteristics of the dense-phase pulverized coal airflow, reducing the ignition temperature and ignition distance of the pulverized coal airflow, and increasing the pulverized coal combustion rate. This allows the heat generated by the combustion of a small amount of pulverized coal to ignite most of the pulverized coal, significantly improving burner performance and greatly increasing oxygen utilization efficiency. Furthermore, the recommended pure oxygen injection temperature for the oxygen-enriched channel 67 is 100°C-200°C.

[0062] Based on the above-described combustion system, in a second aspect of this application, a method for controlling the combustion system is also provided, the method comprising: S1: Confirm the type of coal used in furnace 7; Coal types are classified into low volatile matter (V) coal, such as lean coal and anthracite. daf Coal types with ≤20% content, and bituminous coal (V daf =20-40%), lignite (V daf For high volatile coal types (≥40%), the control methods implemented by the combustion system vary depending on the type of coal.

[0063] S2: Under the condition that the coal type is low volatile coal, confirm the load of furnace 7; that is, the control strategy implemented will be different depending on the load of furnace 7.

[0064] S21: If the load of furnace 7 is the first threshold, close the first regulating valve 35, the second regulating valve 37 and the third regulating valve 39 of flue gas circulation pipeline 3, control the switching device 4 to operate, and connect the first inlet and the second outlet of the switching device 4.

[0065] For example, when the first threshold is greater than or equal to 45%, the flue gas recirculation pipeline 3 is closed, and the switching device 4 is adjusted so that the air-coal airflow directly enters the primary air channel 61. The tilt angle α of the separator 621 is adjusted according to the specific load size to control the lean coal concentration ratio at 1.4:1-2.75:1 and the anthracite concentration ratio at 1.6:1-4:1. At the same time, the distance L between the blunt body 65 and the air outlet of the primary air channel 61 is shortened, thereby obtaining a larger high-temperature reflux zone, strengthening the mixing of coal powder particles and air, making combustion more complete, creating an oxygen-deficient environment, and inhibiting the generation of nitrogen oxides.

[0066] S22: If the load of furnace 7 is the second threshold, and the second threshold is less than the first threshold, open the first regulating valve 35 and the second regulating valve 37 of flue gas circulation pipeline 3, close the third regulating valve 39, control the switching device 4 to operate, and connect the first inlet and the second outlet of the switching device 4.

[0067] For example, when the second threshold is between 35% and 45%, the switching device 4 is adjusted so that the air-coal airflow directly enters the primary air channel 61. The axial inclination angle α between the separating plate 621 and the primary air channel 61 is kept at its maximum, and the distance L between the blunt body 65 and the outlet end of the primary air channel 61 is kept at its minimum. The high-temperature flue gas discharged from the furnace 7 and the medium-temperature flue gas discharged from the economizer 8 are mixed. The high-temperature and medium-temperature flue gas are used to partially preheat and decompose the primary air-coal during transport, allowing some volatiles to be released, reducing the difficulty of ignition and combustion of the pulverized coal. Furthermore, the low oxygen content of the circulating flue gas prevents the released volatiles from prematurely igniting and burning in the pulverized coal pipeline. After entering the furnace 7, it also absorbs additional heat generated by combustion, reducing the peak combustion temperature and thus reducing NOx generation during combustion. In specific implementation, the flue gas mixed with lean coal is controlled at 450℃-550℃, and the flue gas mixed with anthracite is controlled at 550℃-650℃.

[0068] S23: If the load of furnace 7 is the third threshold, and the third threshold is less than the second threshold, open the first regulating valve 35 of flue gas circulation pipeline 3, close the second regulating valve 37 and the third regulating valve 39, control the switching device 4 to operate, and connect the first inlet and the first outlet of the switching device 4. For example, when the third threshold is between 25% and 35%, the high-temperature flue gas from the furnace 7 is mixed with primary air pulverized coal before entering the separation device 5. The high-temperature flue gas is used to partially preheat and decompose the primary air pulverized coal during transport, allowing some volatiles to be released, thus reducing the difficulty of ignition and combustion of the pulverized coal. The primary air pulverized coal mixed with the high-temperature flue gas then enters the separation device 5. Most of the pulverized coal forms a dense phase airflow under centrifugal force, which flows out of the collection pipe and into the upper part of the primary air channel 61. A very small portion of the pulverized coal forms a light phase airflow under centrifugal force, which enters the lower part of the primary air channel 61, resulting in a pulverized coal distribution that is denser at the top and lighter at the bottom. The distance L between the blunt body 65 and the outlet end of the primary air channel 61 is kept to a minimum. The separation plate 621 within the primary air channel 61 is adjusted to maximize its axial inclination angle α with the primary air channel 61, further enhancing the separation effect and achieving a concentration ratio of 9:1. The high concentration of dense-phase pulverized coal significantly reduces ignition heat and improves stable combustion under low load. Furthermore, due to the oxygen-deficient state in the early stages of ignition, it effectively inhibits the formation of nitrogen oxides.

[0069] S24: If the load of furnace 7 is the fourth threshold, and the fourth threshold is less than the second threshold, open the second regulating valve 37 of flue gas circulation pipeline 3, close the first regulating valve 35 and the third regulating valve 39, control the switching device 4 to operate, and connect the first inlet and the first outlet of the switching device 4.

[0070] For example, when the fourth threshold is between 15% and 25%, the switching device 4 is adjusted, and the medium-temperature flue gas from the economizer 8 is mixed and preheated with primary air pulverized coal before entering the separation device 5. The primary air pulverized coal mixed with the medium-temperature flue gas then enters the separation device 5. Most of the pulverized coal forms a dense phase airflow under centrifugal force, which flows out of the collection pipe and into the upper part of the primary air channel 61. A very small portion of the pulverized coal forms a light phase airflow under centrifugal force, which enters the lower part of the primary air channel 61, resulting in a pulverized coal distribution that is denser at the top and lighter at the bottom. The distance L between the blunt body 65 and the outlet end of the primary air channel 61 is kept to a minimum. The separation plate 621 in the primary air channel 61 is adjusted to maximize its axial inclination angle α with the primary air channel 61, further enhancing the separation effect and achieving a concentration ratio of 9:1. Open the oxygen enrichment regulating valve 69 to inject high-purity oxygen into the dense-phase pulverized coal section of the furnace 7, controlling the overall oxygen enrichment concentration of anthracite at 30%, the overall oxygen enrichment concentration of lean coal at 27%, the local oxygen enrichment concentration of anthracite at 60%, and the local oxygen enrichment concentration of lean coal at 50%. Oxygen enrichment reduces the ignition heat of pulverized coal, and the heat generated by the combustion of a small amount of pulverized coal ignites most of the pulverized coal, achieving stable combustion under ultra-low load.

[0071] Furthermore, in some embodiments, the control method further includes: S3: Under the condition that the coal type is high volatile coal, confirm the load of furnace 7; S31: If the load of furnace 7 is the fifth threshold, close the first regulating valve 35, the second regulating valve 37 and the third regulating valve 39 of flue gas circulation pipeline 3, control the switching device 4 to operate, and connect the first inlet and the second outlet of the switching device 4.

[0072] For example, if the fifth threshold is greater than or equal to 30%, the coal-air mixture directly enters the primary air duct 61. The louvered blade angle α is adjusted according to the specific load to control the bituminous coal concentration ratio at 1.3:1-2:1 and the lignite concentration ratio at 1:1-1.6:1. Simultaneously, the distance L between the blunt body 65 and the outlet of the primary air duct 61 is shortened, thereby obtaining a larger high-temperature recirculation zone. This enhances the mixing of coal particles with air, resulting in more complete combustion, creating an oxygen-deficient environment, and inhibiting the formation of nitrogen oxides.

[0073] S32: If the load of furnace 7 is the sixth threshold, and the sixth threshold is less than the fifth threshold, close the first regulating valve 35 of flue gas circulation pipeline 3, open the second regulating valve 37 and the third regulating valve 39, control the switching device 4 to operate, and connect the first inlet and the first outlet of the switching device 4.

[0074] For example, the sixth threshold is between 20% and 30%. The medium-temperature flue gas from the economizer 8 and the low-temperature flue gas from the dust collector 11 are mixed to form medium-low temperature flue gas, which is controlled between 200°C and 300°C. The medium-low temperature flue gas is mixed with the primary air pulverized coal, and the medium-low temperature flue gas is used to preheat the primary air pulverized coal during transportation, forming latent heat fuel and reducing the difficulty of pulverized coal ignition and combustion. In addition, the low oxygen content of the circulating flue gas can prevent the volatiles released from the coal pulverized coal from igniting and burning prematurely in the coal pulverized coal pipeline. After entering the furnace 7, it will also absorb the heat generated by combustion, reducing the peak temperature of combustion and thus reducing the formation of NOx during combustion. The primary air pulverized coal mixed with the medium-low temperature flue gas enters the separation device 5. Most of the coal pulverized coal forms a dense phase airflow under centrifugal force. The dense phase airflow flows out from the powder collection pipe and enters the upper part of the primary air channel 61. A very small portion of the coal pulverized coal forms a light phase airflow under centrifugal force. The light phase airflow enters the lower part of the primary air channel 61, forming a coal pulverized coal distribution that is dense at the top and light at the bottom. Maintaining a large axial inclination angle α between the separator 621 and the primary air channel 61, while minimizing the distance L between the blunt body 65 and the outlet of the primary air channel 61, further enhances the concentration-lean separation effect, resulting in a concentration ratio of approximately 4:1. The highly concentrated dense-phase pulverized coal significantly reduces ignition heat and improves stable combustion under low loads. Furthermore, due to the oxygen-deficient state during the initial ignition phase, it effectively inhibits the formation of nitrogen oxides.

[0075] S3: If the load of furnace 7 is the seventh threshold, and the seventh threshold is less than the sixth threshold, open the second regulating valve 37 of flue gas circulation pipeline 3, close the first regulating valve 35 and the third regulating valve 39, control the switching device 4 to operate, and connect the first inlet and the first outlet of the switching device 4.

[0076] For example, with the seventh threshold at 10%-20%, the medium-temperature flue gas from the economizer 8 is mixed and preheated with the primary air pulverized coal. The primary air pulverized coal mixed with the medium-temperature flue gas enters the separation device 5. Most of the pulverized coal forms a dense phase airflow under centrifugal force, which flows out from the pulverized coal collection pipe and enters the upper part of the primary air channel 61. A very small portion of the pulverized coal forms a light phase airflow under centrifugal force, which enters the lower part of the primary air channel 61, resulting in a pulverized coal distribution that is denser at the top and lighter at the bottom. The distance L between the blunt body 65 and the outlet end of the primary air channel 61 is kept to a minimum. The separation plate 621 in the primary air channel 61 is adjusted to maximize its axial inclination angle α with the primary air channel 61, further enhancing the separation effect and achieving a concentration ratio of 9:1. The oxygen enrichment regulating valve 69 is opened to inject high-purity oxygen into the dense phase pulverized coal area in the furnace 7, controlling the overall oxygen enrichment concentration at 23%-26%, with a local oxygen enrichment concentration reaching 40%-50%. Oxygen enrichment reduces the ignition heat of pulverized coal, and the heat generated by the combustion of a small amount of pulverized coal ignites most of the pulverized coal, achieving stable combustion under ultra-low load.

[0077] As described above, for low-volatile coal types such as anthracite and lean coal with adjusted load: at 45%-100% load, only the separator 621 and the blunt body 65 are adjusted; at 35%-45% load, medium-temperature and high-temperature flue gas are used for preheating; at 25%-35% load, high-temperature flue gas is used for preheating, while the separation effect is enhanced by the separation device 5; at 15%-25% load, local oxygen enrichment technology is further introduced to precisely supplement oxygen for combustion. For high-volatile coal types such as bituminous coal and lignite with adjusted load: at 30%-100% load, only the separator 621 and the blunt body 65 are adjusted; at 20%-30% load, low-temperature and medium-temperature flue gas are used for preheating, while the separation effect is enhanced by the separation device 5; at 10%-20% load, medium-temperature flue gas is used for preheating combined with the separation device 5 to enhance separation, and local oxygen enrichment technology is further introduced to precisely supplement oxygen for combustion.

[0078] The instruction manual requires the following definition: Coal powder concentration ratio R: Coal powder mass concentration ρ in the dense phase gas stream. rich The mass concentration ρ of pulverized coal in the light phase gas flow light The ratio.

[0079] In summary, the full-load multi-coal type modulated oxygen-enriched combustion system and its control method provided in this application, through the combination of pipeline switching, pulverized coal concentration and separation, localized precise oxygen enrichment, and multi-element flue gas recirculation technology, can achieve both stable combustion and low NOx emissions under ultra-low load (10%-15%) conditions for multiple coal types (lignite, bituminous coal, lean coal, and anthracite). Compared with traditional solutions, the oxygen enrichment technology in this application is highly economical, has low investment and operating costs, a wide adjustable range of concentration ratios, high utilization rate of recirculated flue gas, and significant effects on stable combustion and NOx reduction. This application can achieve stable combustion at 10%-100% full load while controlling NOx emissions at the lowest load (10-15%) to not exceed 50% of those at full load operation.

[0080] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0081] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0082] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0083] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0084] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A full-load multi-coal type modulated oxygen-enriched combustion system, characterized in that, The combustion system includes: The burner, furnace, economizer, and dust collector are connected in sequence. The flue gas circulation pipeline includes a first flue gas pipeline, a second flue gas pipeline, and a third flue gas pipeline. The inlet of the first flue gas pipeline is connected to the furnace, and a first fan and a first regulating valve are installed on the first flue gas pipeline. The inlet of the second flue gas pipeline is connected to the outlet of the economizer, and a second fan and a second regulating valve are installed on the second flue gas pipeline. The inlet of the third flue gas pipeline is connected to the outlet of the dust collector, and a third fan and a third regulating valve are installed on the third flue gas pipeline. Primary air-powder piping; The switching device has a first inlet, a first outlet, and a second outlet. The first inlet of the switching device is switchably connected to one of the first outlet and the second outlet. The first inlet is connected to the outlet of the first flue gas duct, the outlet of the second flue gas duct, the outlet of the third flue gas duct, and the outlet of the primary air-coal duct, respectively. A concentration separation device has a second inlet, a third outlet, and a fourth outlet. The second inlet of the concentration separation device is connected to the third outlet and the fourth outlet. The second inlet of the concentration separation device is connected to the first outlet of the switching device. The concentration of the gas flow discharged from the third outlet is greater than the concentration of the gas flow discharged from the fourth outlet. An air supply device includes a primary air duct, which has an air supply end and an air outlet end. The air supply end of the primary air duct is connected to the second outlet of the switching device, the third outlet of the concentration-lean separation device, and the fourth outlet, respectively. The air outlet end of the primary air duct is connected to the furnace.

2. The full-load multi-coal type modulated oxygen-enriched combustion system according to claim 1, characterized in that, The switching device includes a valve body, a first branch pipe, a second branch pipe, a third branch pipe, and a valve plate, wherein: The first branch pipe, the second branch pipe, and the third branch pipe are respectively connected to the periphery of the valve body at intervals. The end of the first branch pipe away from the valve body is configured as the first inlet, the end of the second branch pipe away from the valve body is configured as the first outlet, and the end of the third branch pipe away from the valve body is configured as the third outlet. The valve body is provided with a first port communicating with the first branch pipe, a second port communicating with the second branch pipe, and a third port communicating with the third support. The valve plate is located within the valve body, is rotatably connected to the valve body, and is situated between the second port and the third port. The valve plate can controllably seal one of the second port and the third port.

3. The full-load multi-coal type modulated oxygen-enriched combustion system according to claim 2, characterized in that, The cross-sectional area of ​​the second inlet is adjustable.

4. The full-load multi-coal type modulated oxygen-enriched combustion system according to claim 1, characterized in that, The primary air duct is horizontal in axis, and its two ends are an air supply end and an air outlet end, respectively. The air supply end is provided with a first connecting port, a second connecting port, and a third connecting port with successively decreasing heights. The first connection port is connected to the third outlet, the second connection port is connected to the second outlet, and the third connection port is connected to the fourth outlet.

5. The full-load multi-coal type modulated oxygen-enriched combustion system according to claim 4, characterized in that, The air supply device also includes: A separation window is disposed within the primary air duct. The separation window includes multiple separation blades spaced apart along the axial direction of the primary air duct. The multiple separation blades are rotatably connected to the side wall of the primary air duct and are inclinedly disposed within the primary air duct. The end of the separation blade near the air outlet is higher than the end near the air supply end. A blunt body is disposed within the primary air duct along the axial direction of the primary air duct. The blunt body is positioned between the separation window and the air supply end. The thickness of the blunt body at the end facing the air supply end is less than the thickness of the blunt body at the end facing the air outlet end. The distance from the blunt body to the side of the air outlet end is adjustable.

6. The full-load multi-coal type modulated oxygen-enriched combustion system according to claim 5, characterized in that, The air supply device further includes an adjustment assembly for driving the separator plates to rotate, the adjustment assembly comprising: The second driving member has a telescopic end that reciprocates along an axial direction parallel to the primary air duct; A first drive rod is connected to the telescopic end of the second drive component. The first drive rod is arranged along an axial direction parallel to the primary air duct, and at least a portion of the first drive rod extends into the primary air duct. A connecting plate is disposed within the primary air duct, the connecting plate is connected to the first drive rod, the connecting plate is disposed on the same side of the plurality of separation plates, and the connecting plate is provided with a sliding groove; A connecting rod is provided in a one-to-one correspondence with the separating plate. One end of the connecting rod is vertically connected to a second connecting rod, which is connected to one end of the connecting rod. The second connecting rod is slidably disposed in the slide groove, and the other end of the connecting rod is connected to the corresponding separating plate. The second drive rod is switchably connected to the telescopic end of the second drive member, and the second drive rod is arranged along an axial direction parallel to the primary air duct. At least a portion of the second drive rod extends into the primary air duct, and the blunt body is connected to the second drive rod.

7. The full-load multi-coal type modulated oxygen-enriched combustion system according to claim 6, characterized in that, The inner wall of the primary air duct is provided with mounting holes for mounting a rotating shaft; The air supply device further includes a locking component for locking the rotating shaft, wherein the locking component and the rotating shaft are respectively configured in a one-to-one correspondence, and the locking component includes: A first locking element is disposed between the side wall of the mounting hole and the rotating shaft, and the first locking element can deform under the action of temperature; A second locking element is disposed between the first locking element and the rotating shaft; the second locking element includes: A locking sleeve is fitted between the first locking member and the rotating shaft, and the locking sleeve is provided with multiple locking channels that extend radially through it. The locking block is slidably positioned within the corresponding locking channel. An elastic element is disposed between the locking block and the locking sleeve.

8. The full-load multi-coal type modulated oxygen-enriched combustion system according to any one of claims 1-8, characterized in that, The air supply device also includes: A secondary air duct is spaced out and fitted around the outside of the primary air duct, and a secondary air fan is installed inside the secondary air duct; An oxygen-enriched channel is provided between the secondary air channel and the primary air channel, and an oxygen-enriched regulating valve is provided inside the oxygen-enriched channel.

9. A control method for a full-load multi-coal type modulated oxygen-enriched combustion system, characterized in that, The control method includes: Confirm the type of coal used in the furnace; Under the condition that the coal type is a low volatile coal type, the load of the furnace is confirmed; If the load of the furnace is the first threshold, the first regulating valve, the second regulating valve and the third regulating valve of the flue gas circulation pipeline are closed, the switching device is controlled to operate, and the first inlet and the second outlet of the switching device are connected. If the load of the furnace is the second threshold, and the second threshold is less than the first threshold, the first regulating valve and the second regulating valve of the flue gas circulation pipeline are opened, the third regulating valve is closed, the switching device is controlled to operate, and the first inlet and the second outlet of the switching device are connected. If the load of the furnace is the third threshold, and the third threshold is less than the second threshold, the first regulating valve of the flue gas circulation pipeline is opened, the second regulating valve and the third regulating valve are closed, the switching device is controlled to operate, and the first inlet and the first outlet of the switching device are connected. If the load of the furnace is the fourth threshold, which is less than the second threshold, the second regulating valve of the flue gas circulation pipeline is opened, the first regulating valve and the third regulating valve are closed, and the switching device is controlled to operate. The first inlet and the first outlet of the switching device are connected.

10. The control method for the combustion system according to claim 9, characterized in that, The control method further includes: Under the condition that the coal type is a high volatile coal type, confirm the load of the furnace; If the load of the furnace is the fifth threshold, the first regulating valve, the second regulating valve and the third regulating valve of the flue gas circulation pipeline are closed, the switching device is controlled to operate, and the first inlet and the second outlet of the switching device are connected. If the load of the furnace is the sixth threshold, and the sixth threshold is less than the fifth threshold, the first regulating valve of the flue gas circulation pipeline is closed, the second regulating valve and the third regulating valve are opened, the switching device is controlled to operate, and the first inlet and the first outlet of the switching device are connected. If the load of the furnace is the seventh threshold, and the seventh threshold is less than the sixth threshold, the second regulating valve of the flue gas circulation pipeline is opened, the first regulating valve and the third regulating valve are closed, the switching device is controlled to operate, and the first inlet and the first outlet of the switching device are connected.

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