Adjustable thermal system combustion stabilizing structure for low calorific value pulverized coal furnace

Abstract

The utility model provides a kind of adjustable heat system combustion-supporting structure for low calorific value pulverized coal furnace, including combustion chamber, the both ends of combustion chamber are equipped with powder inlet device and gas entering device respectively, and powder inlet device and gas entering device are extended to the inside of combustion chamber;The side of the combustion chamber is equipped with outer discharge pipe;The powder inlet device includes pulverized coal conveying pipe, and the pulverized coal conveying pipe is through the outer wall of combustion chamber and extends to the inside of combustion chamber.When using, by setting outer discharge pipe and pulverized coal conveying pipe respectively at the both ends of combustion chamber, coal powder and combustion-supporting gas are respectively input to the inside of combustion chamber, coal powder generates different speed difference after different diameter cyclone groove and straight-flow groove, avoid coal powder too concentrated, and the transportation of coal powder is guided to form cyclone by cyclone groove, increase residence time, at the same time, combustion-supporting gas is blown to coal powder by backflushing hole, make coal powder float, further improve the hovering time of coal powder, reach the effect of improving the stability of coal powder combustion.

Description

Technical Field

[0001] This utility model relates to the field of pulverized coal furnace technology, and in particular to an adjustable thermal system combustion stabilization structure for low-calorific-value pulverized coal furnaces. Background Technology

[0002] Low-calorific-value coal is a fuel variety with a lower calorific value than conventional coal. Its net calorific value on an as-received basis is typically below 12.56 MJ / kg (approximately 3000 kcal / kg). It mainly includes coal gangue, middlings, coal slime, and other production byproducts, as well as low-quality bituminous coal and lignite. After processing through crushing and washing processes, this type of coal can be used in fluidized bed power generation, industrial heating, and other fields.

[0003] Because low-calorific-value coal contains more impurities, its combustion stability is relatively poor compared to high-calorific-value pulverized coal. When low-calorific-value pulverized coal is continuously conveyed into the pulverized coal furnace through a conveying device, it passes through and settles at a relatively fast speed, making it difficult to burn completely in the pulverized coal furnace.

[0004] Therefore, this application proposes an adjustable thermal system combustion stabilization structure for low-calorific-value pulverized coal boilers to improve the combustion stability of low-calorific-value pulverized coal. Utility Model Content

[0005] In view of the shortcomings of the prior art mentioned above, the purpose of this utility model is to provide an adjustable thermal system combustion stabilization structure for low-calorific-value pulverized coal boilers, in order to solve the problem of uneven combustion of low-calorific-value coal mentioned in the prior art.

[0006] To achieve the above and other related objectives, this utility model provides an adjustable thermal system combustion stabilization structure for a low-calorific-value pulverized coal boiler, including a combustion chamber, wherein a pulverized coal inlet device and a gas inlet device are respectively provided at both ends of the combustion chamber, and both the pulverized coal inlet device and the gas inlet device extend into the interior of the combustion chamber; An external exhaust pipe is provided on the side of the combustion chamber; The pulverized coal feeding device includes a pulverized coal conveying pipe that penetrates the outer wall of the combustion chamber and extends into the interior of the combustion chamber. One end of the pulverized coal conveying pipe located inside the combustion chamber is provided with a pulverized coal distribution pipe. The end of the pulverized coal distribution pipe is provided with a swirl tube, and the end of the swirl tube is provided with a swirl groove. The gas inlet device includes an injection pipe that penetrates the outer wall of the combustion chamber and extends into the interior of the combustion chamber. One end of the injection pipe located inside the combustion chamber is provided with a mushroom-shaped jet nozzle, and the surface of the mushroom-shaped jet nozzle is provided with backflow holes.

[0007] Preferably, the swirl channel is a through hole with an inclined angle, and the swirl channel is arranged in an equidistant circular array.

[0008] Preferably, the swirl channel is a multi-layered concentric ring, with the through holes of adjacent rings having opposite inclination angles.

[0009] Preferably, the coal powder distribution pipe is equipped with a retarder inside, and the retarder is provided with a plurality of coal powder distribution holes arranged in an equidistant circular array.

[0010] Preferably, the cyclone tube has a DC groove at its axis, and the retarder has a central DC hole at its axis, the diameter of which is larger than the diameter of the powder equalization hole.

[0011] Preferably, the cross-section of the mushroom nozzle is mushroom-shaped, and the backflow vent extends from the top edge of the mushroom nozzle towards the top.

[0012] Preferably, the top of the mushroom-shaped jet nozzle is a smooth dome, and the backflow vents are distributed around the perimeter of the dome.

[0013] Preferably, the mushroom nozzle has a plurality of airflow barrier generating holes on its side, and the plurality of airflow barrier generating holes are equidistantly distributed along the side of the mushroom nozzle.

[0014] Preferably, the bottom of the airflow barrier generating hole is flush with the inner bottom of the mushroom nozzle.

[0015] Preferably, the air injection pipe extends into the interior of the mushroom nozzle, and the height of the end of the air injection pipe is higher than the height of the backflush vent.

[0016] As described above, the adjustable thermal system combustion stabilization structure for low-calorific-value pulverized coal boilers of this utility model has the following beneficial effects: 1. This utility model introduces pulverized coal and combustion-supporting gas into the combustion chamber by setting an external discharge pipe and a pulverized coal conveying pipe at both ends of the combustion chamber. The pulverized coal generates different velocity differences after passing through swirling channels and direct current channels of different diameters, which avoids the pulverized coal from being too concentrated. The swirling channels guide the conveying of pulverized coal to form a swirling flow, increasing the residence time. At the same time, the combustion-supporting gas is blown onto the pulverized coal through the backflushing air holes, causing the pulverized coal to float and further increasing the suspension time of the pulverized coal, thereby improving the combustion stability of pulverized coal.

[0017] 2. This utility model sets a retarder inside the pulverized coal distribution pipe and sets several pulverization holes on the retarder. When the pulverized coal passes through, it will be divided by the pulverization holes, making the pulverized coal more evenly dispersed. Moreover, the retarder can reduce the exit velocity of the pulverized coal and increase the residence time of the pulverized coal in the combustion chamber, which can effectively improve the combustion completeness of the pulverized coal.

[0018] 3. This utility model provides an airflow barrier generating hole on the side of the mushroom-shaped jet nozzle. The airflow ejected from the airflow barrier generating hole can form an airflow barrier, which can greatly slow down the speed at which coal dust falls to the bottom of the combustion chamber. Furthermore, the airflow blown into the combustion chamber through the airflow barrier generating hole will form two airflows, one upward and one downward. The upward airflow will cause the suspended coal dust to continue to rise, while the downward airflow will cause the coal dust accumulated at the bottom of the combustion chamber to be resuspended, thereby further improving the combustion efficiency.

[0019] Therefore, this utility model effectively overcomes the various shortcomings of the prior art and has high industrial application value. Attached Figure Description

[0020] Figure 1 The diagram shown is a cross-sectional view of the structure of this utility model.

[0021] Figure 2 The diagram shown is a structural schematic of the powder feeding device of this utility model.

[0022] Figure 3 The diagram shown is a cross-sectional view of the powder feeding device of this utility model.

[0023] Figure 4 This utility model is shown. Figure 3 A magnified schematic diagram of the structure at point A in the middle.

[0024] Figure 5 The diagram shown is a structural schematic of the gas entry device of this utility model.

[0025] Figure 6 The diagram shown is a cross-sectional view of the gas inlet device of this utility model.

[0026] Component designation explanation: 1. Combustion chamber; 11. External exhaust pipe; 2. Pulverized coal feeding device; 21. Pulverized coal conveying pipe; 22. Pulverized coal distribution pipe; 23. Cyclone tube; 24. Cyclone trough; 25. Direct current trough; 26. Retarder; 27. Pulverized coal distribution hole; 28. Central direct current hole; 3. Gas inlet device; 31. Gas injection pipe; 32. Mushroom-shaped nozzle; 33. Backflow port; 34. Airflow barrier generation port. Detailed Implementation

[0027] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification.

[0028] Please see Figures 1 to 6It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of this invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and are not intended to limit the scope of this invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention.

[0029] like Figure 1 , Figure 2 and Figure 5 As shown, this utility model provides an adjustable thermal system combustion stabilization structure for a low-calorific-value pulverized coal boiler, including a combustion chamber 1. A pulverized coal inlet device 2 and a gas inlet device 3 are respectively provided at both ends of the combustion chamber 1. Both the pulverized coal inlet device 2 and the gas inlet device 3 extend into the interior of the combustion chamber 1. The pulverized coal inlet device 2 is used to convey pulverized coal into the combustion chamber 1, and the gas inlet device 3 is used to convey combustion-supporting gas into the combustion chamber 1. The pulverized coal inlet device 2 and the gas inlet device 3 convey pulverized coal and gas in opposite directions, thereby creating a counter-current effect between the pulverized coal and the gas, which increases the residence time of the pulverized coal and makes the pulverized coal distribution more uniform. Both the pulverized coal inlet device 2 and the gas inlet device 3 are equipped with control valves to control the flow rate of the pulverized coal inlet device 2 and the gas inlet device 3, thereby controlling the combustion volume inside the combustion chamber 1. The combustion chamber 1 is provided with an external exhaust pipe 11 on its side, which is used for heat exhaust and / or flue gas exhaust. The combustion chamber 1 is also provided with an igniter (not shown in the figure) for igniting pulverized coal.

[0030] Specifically, the pulverized coal feeding device 2 includes a pulverized coal conveying pipe 21, which is connected to an external pulverized coal conveying device. The pulverized coal conveying pipe 21 penetrates the outer wall of the combustion chamber 1 and extends into the interior of the combustion chamber 1. Part of the heat from the combustion of pulverized coal in the combustion chamber 1 is conducted to the pulverized coal conveying pipe 21, thereby preheating the pulverized coal conveyed through the pulverized coal conveying pipe 21. One end of the pulverized coal conveying pipe 21 located inside the combustion chamber 1 is provided with a pulverized coal distribution pipe 22. The end of the pulverized coal distribution pipe 22 is provided with a swirl pipe 23, and the end of the swirl pipe 23 is provided with a swirl groove 24. After the pulverized coal enters the swirl pipe 23 through the pulverized coal conveying pipe 21, some of the pulverized coal directly enters the interior of the combustion chamber 1 through the swirl groove 24 to participate in combustion, while some of the pulverized coal is blocked by the swirl pipe 23 and flows back into the pulverized coal distribution pipe 22 to collide with the subsequent pulverized coal to slow down the conveying speed, thereby increasing the residence time of the pulverized coal in the combustion chamber 1 and improving the combustion rate. The gas inlet device 3 includes an injection pipe 31, which is connected to an external combustion-supporting gas input device. The injection pipe 31 penetrates the outer wall of the combustion chamber 1 and extends into the interior of the combustion chamber 1. A mushroom-shaped jet nozzle 32 is provided at one end of the injection pipe 31 inside the combustion chamber 1. The surface of the mushroom-shaped jet nozzle 32 is provided with a backflow hole 33. The combustion-supporting gas enters the mushroom-shaped jet nozzle 32 through the injection pipe 31 to increase the delivery cross section, and then is ejected through the backflow hole 33 to increase the oxygen content in the combustion chamber 1 and improve the combustion efficiency. At the same time, the gas ejected from the backflow hole 33 can lift the pulverized coal ejected from the swirl channel 24, allowing the pulverized coal to suspend for a longer time. The opposing gas and pulverized coal can be more fully mixed inside the combustion chamber 1, which can further improve the combustion stability and combustion efficiency.

[0031] like Figure 3 and Figure 4 As shown in some embodiments, the swirl channel 24 of this utility model is a through hole with an inclined angle. The swirl channel 24 is arranged in an equidistant circular array. When the coal powder passes through the swirl channel 24, it will be guided by the inclined angle of the swirl channel 24 to generate swirl. The generated coal powder swirl can effectively improve the mixing efficiency of coal powder and combustion-supporting gas and improve the stability of coal powder combustion.

[0032] like Figure 3 and Figure 4 As shown in some embodiments, the swirl channel 24 of this utility model is a multi-layered concentric ring, with the through holes of two adjacent rings having opposite inclination angles, and the coal powder ejected from adjacent annular swirl channels 24 rotating in opposite directions. When the two swirls collide, the rotating airflow will form a disordered airflow, which will allow the coal powder to stay for a longer time and burn more evenly.

[0033] like Figure 3 As shown in some embodiments, the coal powder distribution pipe 22 of this utility model is provided with a retarder 26 inside. The retarder 26 is provided with a plurality of coal powder distribution holes 27 arranged in an equidistant circular array. The coal powder conveyed by the coal powder conveying pipe 21 will be blocked by the retarder 26 and then divided into multiple streams through the coal powder distribution holes 27 and enter the swirl tube 23. This avoids the coal powder conveying being too concentrated and resulting in insufficient combustion, thereby improving the uniformity of coal powder transmission and improving combustion efficiency.

[0034] like Figure 3 As shown, in some embodiments, the swirl tube 23 of this invention has a DC groove 25 on its axis, allowing some coal powder to pass directly and generate a velocity difference with the surrounding coal powder, so that the coal powder is burned in stages and the combustion efficiency is improved; the retarder 26 has a central DC hole 28 on its axis, the diameter of the central DC hole 28 is larger than the diameter of the powder equalization hole 27, so that larger coal powder particles pass through first to avoid clogging the coal powder equalization pipe 22, and at the same time, allow some coal powder to pass through the retarder 26 first to generate a velocity difference.

[0035] like Figure 5 and Figure 6 As shown, in some embodiments, the cross-section of the mushroom-shaped jet nozzle 32 of this invention is mushroom-shaped, making the top of the mushroom-shaped jet nozzle 32 arc-shaped. The backflow port 33 extends along the top edge of the mushroom-shaped jet nozzle 32 to the top, so that the gas ejected from the backflow port 33 is ejected at an angle and layered inside and outside, which can better suspend the pulverized coal in the combustion chamber 1.

[0036] like Figure 5 As shown, in some embodiments, the top of the mushroom-shaped jet nozzle 32 of this invention is a smooth dome to block coal dust and reduce the amount of coal dust entering the interior of the mushroom-shaped jet nozzle 32. The backflush vents 33 are distributed around the periphery of the dome to avoid the top of the mushroom-shaped jet nozzle 32, so as to prevent coal dust from the high-speed conveying point at the DC slot 25 from directly entering the interior of the mushroom-shaped jet nozzle 32 through the backflush vents 33.

[0037] like Figure 1 and Figure 5 As shown, in some embodiments, the mushroom-shaped jet nozzle 32 of this invention has a plurality of airflow barrier generating holes 34 on its side. The plurality of airflow barrier generating holes 34 are equidistantly distributed along the side of the mushroom-shaped jet nozzle 32. The airflow ejected from the airflow barrier generating holes 34 can form an airflow barrier. The airflow barrier can greatly slow down the speed at which the coal powder falls to the bottom of the combustion chamber 1. The airflow blown into the combustion chamber 1 through the airflow barrier generating holes 34 will form two airflows, one upward and one downward. The upward airflow will cause the suspended coal powder to continue to rise, and the downward airflow will cause the coal powder accumulated at the bottom of the combustion chamber 1 to be suspended again. At the same time, the coal powder and the heat of combustion will be blocked by the airflow barrier, which will increase the pressure in the combustion chamber 1 and improve the combustion effect. When the pressure is greater than the blocking force of the airflow barrier, it will be discharged from the external discharge pipe 11.

[0038] like Figure 6 As shown, in some embodiments, the bottom of the airflow barrier generating hole 34 of this utility model is flush with the inner bottom of the mushroom nozzle 32. Some of the coal dust that enters the inside of the mushroom nozzle 32 from the backflow hole 33 can be discharged from the inside of the mushroom nozzle 32 through the airflow barrier generating hole 34 under the action of airflow, thus avoiding the accumulation of coal dust and clogging of the mushroom nozzle 32.

[0039] like Figure 6 As shown, in some embodiments, the gas injection pipe 31 of this invention extends into the interior of the mushroom-shaped jet nozzle 32, and the height of the end of the gas injection pipe 31 is higher than the height of the backflushing air hole 33. When the coal powder enters the interior of the mushroom-shaped jet nozzle 32 through the backflushing air hole 33, the raised gas injection pipe 31 can prevent the coal powder from entering the gas injection pipe 31 and causing blockage. At the same time, the input gas will diffuse along the inner top of the mushroom-shaped jet nozzle 32 to the periphery, preferentially ejected from the airflow barrier generating hole 34 to form an airflow barrier, and then ejected from the backflushing air hole 33 to flush the coal powder and increase the suspension time of the coal powder.

[0040] In summary, the adjustable thermal system combustion stabilization structure for a low-calorific-value pulverized coal boiler of this invention, by setting an external discharge pipe 11 and a pulverized coal conveying pipe 21 at both ends of the combustion chamber 1 to respectively input pulverized coal and combustion-supporting gas into the combustion chamber 1, generates different velocity differences after the pulverized coal passes through swirl channels 24 and direct current channels 25 of different diameters, avoiding excessive concentration of pulverized coal. Furthermore, the swirl channel 24 guides the conveying of pulverized coal to form a swirling flow, increasing the residence time. At the same time, the combustion-supporting gas is blown onto the pulverized coal through the backflushing air hole 33, causing the pulverized coal to float, further increasing the suspension time of the pulverized coal, thereby achieving the effect of improving the combustion stability of pulverized coal.

[0041] This invention provides a retarder 26 inside the pulverized coal distribution pipe 22, and a plurality of pulverizing holes 27 on the retarder 26. When the pulverized coal passes through, it is divided by the pulverizing holes 27, making the pulverized coal more evenly dispersed. Furthermore, the retarder 26 reduces the exit velocity of the pulverized coal and increases the residence time of the pulverized coal in the combustion chamber 1, which can effectively improve the combustion completeness of the pulverized coal.

[0042] This invention provides an airflow barrier generating hole 34 on the side of the mushroom-shaped jet nozzle 32. The airflow ejected from the airflow barrier generating hole 34 can form an airflow barrier, which can greatly slow down the speed at which coal dust falls to the bottom of the combustion chamber 1. Furthermore, the airflow blown into the combustion chamber 1 through the airflow barrier generating hole 34 will form two airflows, one upward and one downward. The upward airflow will cause the suspended coal dust to continue to rise, while the downward airflow will cause the coal dust accumulated at the bottom of the combustion chamber 1 to be suspended again, thereby further improving the combustion efficiency.

[0043] Therefore, this utility model effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0044] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A combustion stabilization structure for an adjustable thermal system in a low-calorific-value pulverized coal boiler, characterized in that, It includes a combustion chamber (1), and a powder inlet device (2) and a gas inlet device (3) are respectively provided at both ends of the combustion chamber (1). The powder inlet device (2) and the gas inlet device (3) both extend into the interior of the combustion chamber (1); The combustion chamber (1) is provided with an external exhaust pipe (11) on its side. The coal feeding device (2) includes a coal powder conveying pipe (21), which penetrates the outer wall of the combustion chamber (1) and extends into the interior of the combustion chamber (1). One end of the coal powder conveying pipe (21) located inside the combustion chamber (1) is provided with a coal powder equalization pipe (22), and the end of the coal powder equalization pipe (22) is provided with a swirl pipe (23), and the end of the swirl pipe (23) is provided with a swirl groove (24). The gas inlet device (3) includes an injection pipe (31), which penetrates the outer wall of the combustion chamber (1) and extends into the interior of the combustion chamber (1). One end of the injection pipe (31) located inside the combustion chamber (1) is provided with a mushroom nozzle (32), and the surface of the mushroom nozzle (32) is provided with a backflow hole (33).

2. The adjustable thermal system combustion stabilization structure for a low-calorific-value pulverized coal boiler according to claim 1, characterized in that: The swirl channel (24) is a through hole with an inclined angle, and the swirl channel (24) is arranged in an equidistant circular array.

3. The adjustable thermal system combustion stabilization structure for a low-calorific-value pulverized coal boiler according to claim 2, characterized in that: The swirl channel (24) is a ring with multiple concentric rings, and the through holes of adjacent rings have opposite inclination angles.

4. The adjustable thermal system combustion stabilization structure for a low-calorific-value pulverized coal boiler according to claim 3, characterized in that: The inside of the coal powder distribution pipe (22) is provided with a retarder (26), and the retarder (26) is provided with a number of coal powder distribution holes (27) arranged in an equidistant circular array.

5. The adjustable thermal system combustion stabilization structure for a low-calorific-value pulverized coal boiler according to claim 4, characterized in that: The cyclone tube (23) has a DC groove (25) at its axis, and the retarder (26) has a central DC hole (28) at its axis. The diameter of the central DC hole (28) is larger than the diameter of the powder equalization hole (27).

6. The adjustable thermal system combustion stabilization structure for a low-calorific-value pulverized coal boiler according to claim 1, characterized in that: The cross-section of the mushroom-shaped nozzle (32) is mushroom-shaped, and the backflow vent (33) extends from the top edge of the mushroom-shaped nozzle (32) to the top.

7. The adjustable thermal system combustion stabilization structure for a low-calorific-value pulverized coal boiler according to claim 6, characterized in that: The top of the mushroom-shaped jet nozzle (32) is a smooth dome, and the backflow vents (33) are distributed around the perimeter of the dome.

8. The adjustable thermal system combustion stabilization structure for a low-calorific-value pulverized coal boiler according to claim 7, characterized in that: The mushroom nozzle (32) has a plurality of airflow barrier generating holes (34) on its side, and the plurality of airflow barrier generating holes (34) are equidistantly distributed along the side of the mushroom nozzle (32).

9. The adjustable thermal system combustion stabilization structure for a low-calorific-value pulverized coal boiler according to claim 8, characterized in that: The bottom of the airflow barrier generating hole (34) is flush with the inner bottom of the mushroom nozzle (32).

10. The adjustable thermal system combustion stabilization structure for a low-calorific-value pulverized coal boiler according to claim 7, characterized in that: The air injection pipe (31) extends into the interior of the mushroom nozzle (32), and the height of the end of the air injection pipe (31) is higher than the height of the backflow port (33).

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