A plasma ignition self-sustaining stable combustion low-nitrogen combustion device and method

Abstract

A plasma ignition self-sustaining stable combustion low-nitrogen combustion device and method, wherein a stable combustion chamber is formed inside the main shell of the combustion device, and a burner nozzle connected to the stable combustion chamber is formed at one end of the main shell of the combustion device; a stable combustion ring is arranged inside the stable combustion chamber; the primary air duct is connected to the stable combustion ring, the secondary air duct is connected to the stable combustion chamber, and the primary air duct is connected to the plasma ignition device; a stable combustion ring inlet is arranged at one end of the stable combustion ring close to the plasma ignition device, and a stable combustion ring outlet is arranged at one end of the stable combustion ring close to the burner nozzle; a first reflow zone is arranged on one side of the stable combustion chamber close to the stable combustion ring inlet, and a second reflow zone is arranged on one side of the stable combustion chamber close to the stable combustion ring outlet. The heat flow ejected from the stable combustion ring outlet of the stable combustion ring flows to the first reflow zone through the second reflow zone, and the heat flow flowing to the first reflow zone enters the stable combustion ring through the stable combustion ring inlet to form a heat flow cycle. The present invention can shut down the plasma ignition device after the coal powder combustion reaches the stable combustion condition, and can continue to maintain a stable combustion state for a long time.

Description

Technical Field

[0001] The invention relates to the technical field of pulverized coal ignition, and in particular to a plasma ignition self-sustaining stable combustion low-nitrogen combustion device and method. Background Art

[0002] Industrial boilers are important thermal power equipment in my country's production and life, of which more than 80% are coal-fired boilers, with an annual coal consumption of nearly 640 million tons. my country's coal-fired industrial boilers have many specifications and types, and the furnace types are different. For a long time, my country's coal-fired industrial boilers have generally low thermal efficiency and serious pollutant emissions due to low automation level, large load operation changes, high mechanical incomplete combustion heat loss, large excess air coefficient, unstable coal quality and other reasons.

[0003] In the prior art, coal-fired industrial boilers use oil ignition technology, which makes boiler ignition difficult and poses safety hazards. In addition, it takes a long time for the boiler to go from successful ignition to stable combustion. Compared with oil ignition technology, the plasma ignition and stable combustion technology has the characteristics of stronger ignition ability, safe and reliable system, clean and environmentally friendly. However, at this stage, plasma ignition requires the plasma igniter to work continuously to maintain a stable combustion state. The continuous operation of the plasma igniter consumes a lot of energy and greatly shortens its service life, which leads to a high combustion cost. There is an urgent need for a technical solution that can shut down the plasma igniter after the coal powder is stably burned and can continue to maintain a stable combustion state for a long time. Summary of the invention

[0004] To this end, the present invention provides a plasma ignition self-sustaining stable combustion low-nitrogen combustion device and method, which can shut down the plasma ignition device after the coal powder is stably burned, and can continue to maintain the stable combustion state for a long time, thereby solving the high energy consumption and high cost problems caused by the continuous operation of the plasma ignition device in the prior art.

[0005] In order to achieve the above-mentioned object, the present invention provides the following technical solutions: a plasma ignition self-sustaining stable combustion low-nitrogen combustion device, comprising a combustion device main shell, the combustion device main shell is also connected to a primary air duct and a secondary air duct, a stable combustion cavity is formed inside the combustion device main shell, and a burner nozzle connected to the stable combustion cavity is formed at one end of the combustion device main shell; a stable combustion ring is provided inside the stable combustion cavity;

[0006] The primary air duct is connected to the combustion stabilizing ring, the secondary air duct is connected to the combustion stabilizing cavity, and the primary air duct is connected to a plasma ignition device; a combustion stabilizing ring inlet is provided at one end of the combustion stabilizing ring close to the plasma ignition device, and a combustion stabilizing ring outlet is provided at one end of the combustion stabilizing ring close to the burner nozzle;

[0007] A first reflow zone is provided on a side of the combustion stabilizing cavity close to the inlet of the combustion stabilizing ring, and a second reflow zone is provided on a side of the combustion stabilizing cavity close to the outlet of the combustion stabilizing ring.

[0008] As a preferred solution of the plasma ignition self-sustaining stable combustion low-nitrogen combustion device, the primary air duct is arranged at one end of the main shell of the combustion device, and a secondary air box is arranged at the end of the main shell of the combustion device. The end of the primary air duct is inserted into the stable combustion cavity through the secondary air box and connected to the stable combustion ring;

[0009] The secondary air duct is connected to the secondary air box, and a secondary air ring is arranged between the combustion stabilization chamber and the secondary air box; the secondary air ring is distributed in a ring shape outside the primary air duct.

[0010] As a preferred solution for the plasma ignition self-sustaining stable combustion low-nitrogen combustion device, the end of the plasma ignition device passes through the middle of the secondary air ring and is inserted into the interior of the primary air duct.

[0011] As a preferred solution of the plasma ignition self-sustaining stable combustion low-nitrogen combustion device, the interior of the primary air duct is provided with a double-conical closing, and the end of the plasma ignition device is located at the double-conical closing;

[0012] The end of the primary air duct is internally connected with combustion stabilizing teeth, a drainage channel is formed between the combustion stabilizing teeth, and the combustion stabilizing teeth are arranged in a ring shape.

[0013] As a preferred solution of the plasma ignition self-sustaining stable combustion low-nitrogen combustion device, the primary air duct is arranged on the side of the main shell of the combustion device, and a secondary air box is arranged at the end of the main shell of the combustion device. The primary air duct is inserted into the stable combustion cavity through the secondary air box and connected to the stable combustion ring;

[0014] A first reflow zone is provided on a side of the combustion stabilizing cavity close to the inlet of the combustion stabilizing ring, and a second reflow zone is provided on a side of the combustion stabilizing cavity close to the outlet of the combustion stabilizing ring.

[0015] As a preferred solution of the plasma ignition self-sustaining stable combustion low-nitrogen combustion device, the inner diameter of the burner nozzle is smaller than the inner diameter of the stable combustion ring; the second reflow zone forms a barrier to the heat flow ejected from the outlet edge of the stable combustion ring;

[0016] The inner wall of the combustion stabilizing ring is in a hyperbolic shape, and fixing ribs are connected between the combustion stabilizing ring and the main shell of the combustion device or between the combustion stabilizing ring and the primary air duct.

[0017] The present invention also provides a plasma ignition self-sustaining stable combustion low-nitrogen combustion method, using the above-mentioned plasma ignition self-sustaining stable combustion low-nitrogen combustion device, the heat flow ejected from the stable combustion ring outlet of the stable combustion ring flows to the first reflow zone through the second reflow zone, and the heat flow flowing to the first reflow zone enters the stable combustion ring through the stable combustion ring inlet to form a heat flow cycle;

[0018] Coal powder carrying air is input into the combustion stabilizing ring in the combustion stabilizing chamber through the primary air duct, the injected coal powder is ignited by a plasma igniter, and air is distributed through the secondary air ring of the secondary air duct. When the ignited coal powder follows the heat flow cycle to form a self-sustaining stable combustion state, the plasma ignition device is turned off.

[0019] As a preferred solution for the plasma ignition self-sustaining stable low-nitrogen combustion method, the combustion temperature in the stable combustion chamber is monitored. When the combustion temperature in the stable combustion chamber is less than a first preset value, the plasma ignition device is turned on; when the combustion temperature in the stable combustion chamber is greater than or equal to the first preset value, the plasma ignition device is turned off.

[0020] As a preferred solution for the plasma ignition self-sustaining stable combustion low-nitrogen combustion method, the combustion temperature at the burner nozzle is monitored. When the temperature at the burner nozzle is less than a second preset value, the plasma ignition device is turned on; when the temperature at the burner nozzle is greater than or equal to the second preset value, the plasma ignition device is turned off.

[0021] As a preferred solution for the plasma ignition self-sustaining stable combustion low-nitrogen combustion method, the wind speed change rate in the primary air duct is monitored. When the wind speed change rate in the primary air duct is less than or equal to a third preset value, the plasma ignition device is turned off; when the wind speed change rate in the primary air duct is greater than the third preset value, the plasma ignition device is turned on.

[0022] The main shell of the combustion device of the present invention is connected with a primary air duct and a secondary air duct, a combustion stabilizing cavity is formed inside the main shell of the combustion device, and a burner nozzle connected to the combustion stabilizing cavity is formed at one end of the main shell of the combustion device; a combustion stabilizing ring is provided inside the combustion stabilizing cavity; the primary air duct is connected to the combustion stabilizing ring, the secondary air duct is connected to the combustion stabilizing cavity, and the primary air duct is connected to a plasma ignition device; a combustion stabilizing ring inlet is provided at one end of the combustion stabilizing ring close to the plasma ignition device, and a combustion stabilizing ring outlet is provided at one end of the combustion stabilizing ring close to the burner nozzle; a first reflow zone is provided on one side of the combustion stabilizing cavity close to the combustion stabilizing ring inlet, and a second reflow zone is provided on one side of the combustion stabilizing cavity close to the combustion stabilizing ring outlet. The heat flow ejected from the combustion stabilizing ring outlet of the combustion stabilizing ring flows through the second recirculation zone to the first recirculation zone, and the heat flow flowing to the first recirculation zone enters the combustion stabilizing ring through the combustion stabilizing ring inlet to form a heat flow cycle; the coal powder carrying air is input into the combustion stabilizing ring in the combustion stabilizing cavity through the primary air duct, and the injected coal powder is ignited by a plasma igniter, and the air is distributed through the secondary air ring of the secondary air duct. When the ignited coal powder follows the heat flow cycle to form a self-sustaining stable combustion state, the plasma ignition device is turned off. The present invention can turn off the plasma ignition device after the coal powder combustion reaches the stable combustion condition, and can continue to maintain the stable combustion state for a long time. The plasma ignition device is converted from continuous ignition work to intermittent low-power ignition, which greatly reduces the high power consumption problem caused by the continuous operation of the plasma ignition device and reduces the cost; at the same time, it solves the environmental pollution problems such as black smoke and desulfurization slurry pollution caused by boiler dust emissions during oil-coal mixed combustion. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0024] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment of size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0025] Figure 1 It is a schematic diagram of the structure of a plasma ignition self-sustaining stable combustion low-nitrogen combustion device provided in an embodiment of the present invention;

[0026] Figure 2 It is a schematic diagram of the principle of a plasma ignition self-sustaining stable combustion low-nitrogen combustion device provided in an embodiment of the present invention;

[0027] Figure 3 It is a schematic structural diagram of another plasma ignition self-sustaining stable combustion low-nitrogen combustion device provided in an embodiment of the present invention;

[0028] Figure 4 It is a schematic diagram of the principle of another plasma ignition self-sustaining stable combustion low-nitrogen combustion device provided in an embodiment of the present invention;

[0029] Figure 5 It is a schematic diagram of plasma ignition self-sustaining stable combustion low-nitrogen combustion control provided in an embodiment of the present invention.

[0030] In the figure, 1. main shell of combustion device; 2. primary air duct; 3. secondary air duct; 4. combustion stabilizing chamber; 5. burner nozzle; 6. combustion stabilizing ring; 7. plasma ignition device; 8. combustion stabilizing ring inlet; 9. combustion stabilizing ring outlet; 10. first recirculation zone; 11. second recirculation zone; 12. secondary air box; 13. secondary air ring; 14. combustion stabilizing teeth. DETAILED DESCRIPTION

[0031] The following is a description of the implementation of the present invention by specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] See also Figure 1 , Figure 2 , Figure 3 and Figure 4 , a plasma ignition self-sustaining stable combustion low-nitrogen combustion device is provided, comprising a combustion device main shell 1, the combustion device main shell 1 is also connected to a primary air duct 2 and a secondary air duct 3, a stable combustion chamber 4 is formed inside the combustion device main shell 1, and a burner nozzle 5 connected to the stable combustion chamber 4 is formed at one end of the combustion device main shell 1; a stable combustion ring 6 is provided inside the stable combustion chamber 4;

[0033] The primary air duct 2 is connected to the combustion stabilizing ring 6, the secondary air duct 3 is connected to the combustion stabilizing chamber 4, and the primary air duct 2 is connected to a plasma ignition device 7; a combustion stabilizing ring inlet 8 is provided at one end of the combustion stabilizing ring 6 close to the plasma ignition device 7, and a combustion stabilizing ring outlet 9 is provided at one end of the combustion stabilizing ring 6 close to the burner nozzle 5;

[0034] A first reflow zone 10 is provided on a side of the combustion stabilizing chamber 4 close to the combustion stabilizing ring inlet 8 , and a second reflow zone 11 is provided on a side of the combustion stabilizing chamber 4 close to the combustion stabilizing ring outlet 9 .

[0035] Specifically, a first reflow zone 10 and a second reflow zone 11 are respectively provided on both sides of the combustion stabilizing chamber 4. The first reflow zone 10 and the second reflow zone 11 are both streamlined in design, and can form a heat flow circulation in conjunction with the combustion stabilizing ring outlet 9 and the combustion stabilizing ring inlet 8.

[0036] Specifically, the inner diameter of the burner nozzle 5 is smaller than the inner diameter of the combustion stabilizing ring 6; the second recirculation zone 11 blocks the heat flow ejected from the edge of the combustion stabilizing ring outlet 9. The burner nozzle 5 has a smaller inner diameter than the combustion stabilizing chamber 4, so that the second recirculation zone 11 blocks the heat flow ejected from the edge of the combustion stabilizing ring outlet 9, and part of the heat flow flows back to the first recirculation zone 10 under the obstruction of the second recirculation zone 11, and at the same time flows back to the combustion stabilizing ring inlet 8 under the obstruction of the first recirculation zone 10, thereby forming a heat flow cycle in cooperation with the combustion stabilizing ring outlet 9 and the combustion stabilizing ring inlet 8.

[0037] See again Figure 1 and Figure 2 In this embodiment, the primary air duct 2 is arranged at one end of the main housing 1 of the combustion device, and a secondary air box 12 is arranged at the end of the main housing 1 of the combustion device. The end of the primary air duct 2 is inserted into the combustion stabilizing chamber 4 through the secondary air box 12 and connected to the combustion stabilizing ring 6; a secondary air ring 13 is arranged between the combustion stabilizing chamber 4 and the secondary air box 12; the secondary air ring 13 is distributed in an annular shape outside the primary air duct 2. The end of the plasma ignition device 7 passes through the middle of the secondary air ring 13 and is inserted into the interior of the primary air duct 2.

[0038] Specifically, the primary air duct 2 can be introduced from the outside of the main shell 1 of the combustion device to the secondary air box 12, and the plasma ignition device 7 is inserted into the primary air duct 2. Under this structure, the air distribution of the secondary air duct 3 enters the stable combustion chamber 4 through the secondary air box 12 and the secondary air ring 13, and then the heat flow enters the stable combustion ring 6 and is discharged from the stable combustion ring outlet 9. The second recirculation zone 11 forms a barrier to the heat flow ejected from the edge of the stable combustion ring outlet 9. Part of the heat flow refluxes to the first recirculation zone 10 under the obstruction of the second recirculation zone 11, and at the same time refluxes to the stable combustion ring inlet 8 under the obstruction of the first recirculation zone 10, thereby forming a heat flow circulation in cooperation with the stable combustion ring outlet 9 and the stable combustion ring inlet 8.

[0039] See again Figure 3 and 4 In this embodiment, the primary air duct 2 is provided with a double-conical closing inside, and the end of the plasma ignition device 7 is located at the double-conical closing; the end of the primary air duct 2 is connected to the inside with a stabilizing tooth 14, and a drainage channel is formed between the stabilizing teeth 14, and the stabilizing teeth 14 are arranged in a ring shape. The double-conical closing makes the heat flow more stable, which is conducive to the ignition of the plasma ignition device 7, and the setting of the stabilizing teeth 14 is conducive to achieving a stable combustion state.

[0040] In this embodiment, the primary air duct 2 is arranged on the side of the main housing 1 of the combustion device, and a secondary air box 12 is arranged at the end of the main housing 1 of the combustion device. The primary air duct 2 is inserted into the combustion stabilizing chamber 4 through the secondary air box 12 and connected to the combustion stabilizing ring 6; the combustion stabilizing chamber 4 is provided with a first reflow zone 10 on the side close to the combustion stabilizing ring inlet 8, and the combustion stabilizing chamber 4 is provided with a second reflow zone 11 on the side close to the combustion stabilizing ring outlet 9. The inner diameter of the burner nozzle 5 is smaller than the inner diameter of the combustion stabilizing ring 6; the second reflow zone 11 blocks the heat flow ejected from the edge of the combustion stabilizing ring outlet 9.

[0041] Specifically, the primary air duct 2 can be introduced from the lower side of the main shell 1 of the combustion device, and the primary air duct 2 is inserted into the stable combustion chamber 4 through the secondary air box 12 and connected to the stable combustion ring 6, and the plasma ignition device 7 is inserted into the primary air duct 2. Under this structure, the air distribution of the secondary air duct 3 enters the stable combustion chamber 4 through the secondary air ring 13 through the secondary air box 12, and the heat flow and coal powder of the primary air duct 2 directly enter the plasma ignition device 7 for ignition, and then the heat flow enters the stable combustion ring 6 again and is discharged from the stable combustion ring outlet 9. The second recirculation zone 11 forms a barrier to the heat flow ejected from the edge of the stable combustion ring outlet 9. Part of the heat flow refluxes to the first recirculation zone 10 under the obstruction of the second recirculation zone 11, and at the same time refluxes to the stable combustion ring inlet 8 under the obstruction of the first recirculation zone 10, thereby cooperating with the stable combustion ring outlet 9 and the stable combustion ring inlet 8 to form a heat flow circulation.

[0042] In this embodiment, the inner wall of the stabilizing ring 6 is in a hyperbolic shape, and a fixing rib is connected between the stabilizing ring 6 and the main housing 1 of the combustion device or between the stabilizing ring 6 and the primary air duct 2. The inner wall of the stabilizing ring 6 is in a hyperbolic shape, which is conducive to the formation of a stable combustion state. At the same time, the fixing rib is used to stabilize the stabilizing ring 6 so that the stabilizing ring 6 is in the stable combustion cavity 4. The rib-shaped fixing rib does not affect the heat flow.

[0043] Assistance Figure 1 , Figure 2 , Figure 3 and Figure 4 , see Figure 5 The present invention also provides a plasma ignition self-sustaining stable combustion low-nitrogen combustion method, which is achieved by the above-mentioned plasma ignition self-sustaining stable combustion low-nitrogen combustion device.

[0044] Specifically, the main shell 1 of the combustion device is connected with a primary air duct 2 and a secondary air duct 3, a combustion stabilizing chamber 4 is formed inside the main shell 1 of the combustion device, and a burner nozzle 5 connected to the combustion stabilizing chamber 4 is formed at one end of the main shell 1 of the combustion device; a combustion stabilizing ring 6 is arranged inside the combustion stabilizing chamber 4; the primary air duct 2 and the secondary air duct 3 are both connected to the combustion stabilizing ring 6, and the primary air duct 2 is connected to a plasma ignition device 7; a combustion stabilizing ring inlet 8 is arranged at one end of the combustion stabilizing ring 6 close to the plasma ignition device 7, and a combustion stabilizing ring outlet 9 is arranged at one end of the combustion stabilizing ring 6 close to the burner nozzle 5; a first reflow zone 10 is arranged on one side of the combustion stabilizing chamber 4 close to the combustion stabilizing ring inlet 8, and a second reflow zone 11 is arranged on one side of the combustion stabilizing chamber 4 close to the combustion stabilizing ring outlet 9. Both the first reflow zone 10 and the second reflow zone 11 are streamlined in design, and can form a heat flow cycle in conjunction with the combustion stabilizing ring outlet 9 and the combustion stabilizing ring inlet 8.

[0045] Specifically, the heat flow ejected from the combustion stabilizing ring outlet 9 of the combustion stabilizing ring 6 flows through the second recirculation zone 11 to the first recirculation zone 10, and the heat flow flowing to the first recirculation zone 10 enters the combustion stabilizing ring 6 through the combustion stabilizing ring inlet 8 to form a heat flow circulation; the coal powder carrying air is input into the combustion stabilizing ring 6 in the combustion stabilizing chamber 4 through the primary air duct 2, the injected coal powder is ignited by the plasma ignition device 7, and the air is distributed through the secondary air ring 13 of the secondary air duct 3. When the ignited coal powder follows the heat flow cycle to form a self-sustaining stable combustion state, the plasma ignition device 7 is turned off.

[0046] In one embodiment of the plasma ignition self-sustaining stable combustion low-nitrogen combustion method, the combustion temperature in the stable combustion chamber 4 is monitored. When the combustion temperature in the stable combustion chamber 4 is less than a first preset value, the plasma ignition device 7 is turned on; when the combustion temperature in the stable combustion chamber 4 is greater than or equal to the first preset value, the plasma ignition device 7 is turned off.

[0047] Specifically, the working state of the plasma ignition device 7 is controlled by the combustion temperature in the combustion stabilizing chamber 4. When the combustion temperature in the combustion stabilizing chamber 4 is less than 950°C, the plasma ignition device 7 is turned on. When the combustion temperature in the combustion stabilizing chamber 4 is greater than or equal to 950°C, the plasma ignition device 7 is turned off.

[0048] In one embodiment of the plasma ignition self-sustaining stable combustion low-nitrogen combustion method, the combustion temperature at the burner nozzle 5 is monitored. When the temperature at the burner nozzle 5 is less than a second preset value, the plasma ignition device 7 is turned on; when the temperature at the burner nozzle 5 is greater than or equal to the second preset value, the plasma ignition device 7 is turned off.

[0049] Specifically, the working state of the plasma ignition device 7 is controlled by adjusting the temperature at the burner nozzle 5. When the temperature at the burner nozzle 5 is less than 750°C, the plasma ignition device 7 is turned on. When the temperature at the burner nozzle 5 is greater than or equal to 750°C, the plasma ignition device 7 is turned off.

[0050] In one embodiment of the plasma ignition self-sustaining stable combustion low-nitrogen combustion method, the wind speed change rate in the primary air duct 2 is monitored. When the wind speed change rate in the primary air duct 2 is less than or equal to a third preset value, the plasma ignition device 7 is turned off; when the wind speed change rate in the primary air duct 2 is greater than the third preset value, the plasma ignition device 7 is turned on.

[0051] Specifically, the working state of the plasma ignition device 7 is controlled by the wind speed change rate in the primary air duct 2. When the wind speed change rate in the primary air duct 2 is less than or equal to 0.5 m / s, the plasma ignition device 7 is turned off. When the wind speed change rate in the primary air duct 2 is greater than 0.5 m / s, the plasma ignition device 7 is turned on.

[0052] The main housing 1 of the combustion device of the present invention is connected with a primary air duct 2 and a secondary air duct 3, a combustion stabilizing chamber 4 is formed inside the main housing 1 of the combustion device, and a burner nozzle 5 connected to the combustion stabilizing chamber 4 is formed at one end of the main housing 1 of the combustion device; a combustion stabilizing ring 6 is arranged inside the combustion stabilizing chamber 4; the primary air duct 2 is connected to the combustion stabilizing ring 6, the secondary air duct 3 is connected to the combustion stabilizing chamber 4, and the primary air duct 2 is connected to a plasma ignition device 7; a combustion stabilizing ring inlet 8 is arranged at one end of the combustion stabilizing ring 6 close to the plasma ignition device 7, and a combustion stabilizing ring outlet 9 is arranged at one end of the combustion stabilizing ring 6 close to the burner nozzle 5; a first reflow zone 10 is arranged on one side of the combustion stabilizing chamber 4 close to the combustion stabilizing ring inlet 8, and a second reflow zone 11 is arranged on one side of the combustion stabilizing chamber 4 close to the combustion stabilizing ring outlet 9. The heat flow ejected from the combustion stabilizing ring outlet 9 of the combustion stabilizing ring 6 flows to the first reflow zone 10 through the second reflow zone 11, and the heat flow flowing to the first reflow zone 10 enters the combustion stabilizing ring 6 through the combustion stabilizing ring inlet 8 to form a heat flow cycle. The inner diameter of the burner nozzle 5 is smaller than that of the combustion stabilizing chamber 4, so that the second recirculation zone 11 blocks the heat flow ejected from the edge of the combustion stabilizing ring outlet 9. Part of the heat flow refluxes to the first recirculation zone 10 under the obstruction of the second recirculation zone 11, and at the same time refluxes to the combustion stabilizing ring inlet 8 under the obstruction of the first recirculation zone 10, thereby forming a heat flow circulation in cooperation with the combustion stabilizing ring outlet 9 and the combustion stabilizing ring inlet 8. The primary air duct 2 can be introduced from the outside of the main shell 1 of the combustion device to the secondary air box 12, and the plasma ignition device 7 is inserted into the primary air duct 2. Under this structure, the air distribution of the secondary air duct 3 enters the primary air duct 2 from the air distribution port 13 through the secondary air box 12, and then the heat flow enters the stable combustion ring 6 and is discharged from the stable combustion ring outlet 9. The second recirculation zone 11 forms a barrier to the heat flow ejected from the edge of the stable combustion ring outlet 9. Part of the heat flow refluxes to the first recirculation zone 10 under the barrier of the second recirculation zone 11, and at the same time, it refluxes to the stable combustion ring inlet 8 under the barrier of the first recirculation zone 10, and then cooperates with the stable combustion ring outlet 9 and the stable combustion ring inlet 8 to form a heat flow cycle. The primary air duct 2 can also be introduced from the lower side of the main shell 1 of the combustion device, and the primary air duct 2 is inserted into the stable combustion chamber 4 through the secondary air box 12 and connected to the stable combustion ring 6, and the plasma ignition device 7 is inserted into the primary air duct 2. The heat flow ejected from the combustion stabilizing ring outlet 9 of the combustion stabilizing ring 6 flows through the second recirculation zone 11 to the first recirculation zone 10, and the heat flow flowing to the first recirculation zone 10 enters the combustion stabilizing ring 6 through the combustion stabilizing ring inlet 8 to form a heat flow circulation; the coal powder carrying air is input into the combustion stabilizing ring 6 in the combustion stabilizing chamber 4 through the primary air duct 2, and the injected coal powder is ignited by the plasma ignition device 7. The ignited coal powder follows the heat flow circulation to form a self-sustaining stable combustion state; after the ignition of the coal powder, in the stable combustion state, the plasma ignition device 7 is turned off, and the coal powder in the stable combustion state is supplied with air through the secondary air ring 13 of the secondary air duct 3.The present invention can shut down the plasma ignition device 7 after the coal powder combustion reaches the stable combustion condition, and can continue to maintain the stable combustion state for a long time. The plasma ignition device 7 switches from continuous ignition operation to intermittent low-power ignition, which greatly reduces the high power consumption problem caused by the continuous operation of the plasma ignition device 7 and reduces the cost; at the same time, it solves the environmental pollution problems such as black smoke and desulfurization slurry pollution caused by boiler dust emissions during the mixed combustion of oil and coal.

[0053] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention. The above-described embodiments of the present invention do not constitute a limitation on the scope of protection of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A plasma ignition self-sustaining stable combustion low-nitrogen combustion device, characterized in that: The combustion device comprises a main housing (1), the main housing (1) of the combustion device is further connected to a primary air duct (2) and a secondary air duct (3), a combustion stabilization chamber (4) is formed inside the main housing (1), a burner nozzle (5) communicating with the combustion stabilization chamber (4) is formed at one end of the main housing (1); a combustion stabilization ring (6) is provided inside the combustion stabilization chamber (4); The primary air duct (2) is connected to the combustion stabilizing ring (6), and the secondary air duct (3) is connected to the combustion stabilizing chamber (4); the primary air duct (2) is connected to a plasma ignition device (7); a combustion stabilizing ring inlet (8) is provided at one end of the combustion stabilizing ring (6) close to the plasma ignition device (7), and a combustion stabilizing ring outlet (9) is provided at one end of the combustion stabilizing ring (6) close to the burner nozzle (5); A first reflow zone (10) is provided on a side of the combustion stabilizing chamber (4) close to the combustion stabilizing ring inlet (8), and a second reflow zone (11) is provided on a side of the combustion stabilizing chamber (4) close to the combustion stabilizing ring outlet (9); The inner diameter of the burner nozzle (5) is smaller than the inner diameter of the combustion stabilizing ring (6); the second recirculation zone (11) blocks the heat flow ejected from the edge of the combustion stabilizing ring outlet (9), and part of the heat flow flows back to the first recirculation zone (10) under the obstruction of the second recirculation zone (11).

2. According to claim 1, a plasma ignition self-sustaining stable combustion low-nitrogen combustion device is characterized in that: The primary air duct (2) is arranged at one end of the main shell (1) of the combustion device, and a secondary air box (12) is arranged at the end of the main shell (1) of the combustion device. The end of the primary air duct (2) is inserted into the combustion stabilization chamber (4) through the secondary air box (12) and connected to the combustion stabilization ring (6); The secondary air duct (3) is connected to the secondary air box (12), and a secondary air ring (13) is provided between the combustion stabilization chamber (4) and the secondary air box (12); the secondary air ring (13) is distributed in a ring shape outside the primary air duct (2).

3. According to claim 2, a plasma ignition self-sustaining stable combustion low-nitrogen combustion device is characterized in that: The end of the plasma ignition device (7) passes through the middle of the secondary air ring (13) and is inserted into the interior of the primary air duct (2).

4. According to claim 3, a plasma ignition self-sustaining stable combustion low nitrogen combustion device is characterized in that: The primary air duct (2) is provided with a double-conical closing end inside, and the end of the plasma ignition device (7) is located at the double-conical closing end; The end of the primary air duct (2) is internally connected with a combustion stabilizing tooth (14), a drainage channel is formed between the combustion stabilizing teeth (14), and the combustion stabilizing teeth (14) are arranged in a ring shape.

5. According to claim 1, a plasma ignition self-sustaining stable combustion low nitrogen combustion device is characterized in that: The primary air duct (2) is arranged on the side of the main shell (1) of the combustion device, and a secondary air box (12) is provided at the end of the main shell (1) of the combustion device. The primary air duct (2) is inserted into the combustion stabilization chamber (4) through the secondary air box (12) and is connected to the combustion stabilization ring (6).

6. According to claim 1, a plasma ignition self-sustaining stable combustion low nitrogen combustion device is characterized in that: The inner wall of the combustion stabilizing ring (6) is in the shape of a hyperbolic surface, and fixing ribs are connected between the combustion stabilizing ring (6) and the main shell (1) of the combustion device or between the combustion stabilizing ring (6) and the primary air duct (2).

7. A plasma ignition self-sustaining stable combustion low nitrogen combustion method, characterized in that: A plasma ignition self-sustaining stable combustion low-nitrogen combustion device according to any one of claims 1 to 6 is used, wherein the heat flow ejected from the stable combustion ring outlet (9) of the stable combustion ring (6) flows to the first reflow zone (10) through the second reflow zone (11), and the heat flow flowing to the first reflow zone (10) enters the stable combustion ring (6) through the stable combustion ring inlet (8) to form a heat flow cycle; Coal powder carrying air is input into a combustion stabilizing ring (6) in a combustion stabilizing chamber (4) through a primary air duct (2), the injected coal powder is ignited by a plasma ignition device (7), and air is distributed through a secondary air ring (13) of a secondary air duct (3). When the ignited coal powder follows the heat flow cycle to form a self-sustaining combustion stabilizing state, the plasma ignition device (7) is turned off.

8. The plasma ignition self-sustaining stable combustion low nitrogen combustion method according to claim 7, characterized in that: The combustion temperature in the combustion stabilization chamber (4) is monitored, and when the combustion temperature in the combustion stabilization chamber (4) is less than a first preset value, the plasma ignition device (7) is turned on; when the combustion temperature in the combustion stabilization chamber (4) is greater than the first preset value, the plasma ignition device (7) is turned off.

9. The plasma ignition self-sustaining stable combustion low nitrogen combustion method according to claim 7, characterized in that: The combustion temperature at the burner nozzle (5) is monitored, and when the temperature at the burner nozzle (5) is less than a second preset value, the plasma ignition device (7) is turned on; when the temperature at the burner nozzle (5) is greater than the second preset value, the plasma ignition device (7) is turned off.

10. The plasma ignition self-sustaining stable combustion low nitrogen combustion method according to claim 7, characterized in that: The wind speed change rate in the primary air duct (2) is monitored, and when the wind speed change rate in the primary air duct (2) is less than a third preset value, the plasma ignition device (7) is turned off; when the wind speed change rate in the primary air duct (2) is greater than the third preset value, the plasma ignition device (7) is turned on.

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