阅读说明：本技术 烟气内循环燃烧器 (Flue gas internal circulation combustor ) 是由 薛志村 苏毅 揭涛 李宇 闫玉强 邬文燕 杨冰冰 于 2021-07-14 设计创作，主要内容包括：本发明提供一种烟气内循环燃烧器,其包括：点火枪；一级燃气管,一级燃气管设置有一级燃气喷头,一级燃气管沿径向方向设置在点火枪的外侧；二级燃气管,二级燃气管设置有二级燃气喷头,二级燃气管沿径向方向设置在一级燃气管的外侧；空气导流内筒,空气导流内筒沿径向方向设置在一级燃气管与二级燃气管之间；空气导流外筒,空气导流外筒沿径向方向设置在空气导流内筒外侧；空气导流内筒和空气导流外筒形成文丘里结构,该文丘里结构沿空气在其中的流动方向依次包括收缩段、喉口段和扩散段,空气导流外筒在喉口段设置有烟气循环开口。本发明的烟气内循环燃烧器能够强化烟气内循环效果,促进燃气、助燃空气和烟气混合,无需增设烟气外循环管道。(The invention provides a flue gas internal circulation combustor, which comprises: an ignition gun; the primary gas pipe is provided with a primary gas spray head and is arranged outside the ignition gun along the radial direction; the secondary gas pipe is provided with a secondary gas spray head and is arranged on the outer side of the primary gas pipe along the radial direction; the air diversion inner cylinder is arranged between the primary fuel gas pipe and the secondary fuel gas pipe along the radial direction; the air diversion outer cylinder is arranged outside the air diversion inner cylinder along the radial direction; the air flow guide inner cylinder and the air flow guide outer cylinder form a venturi structure, the venturi structure sequentially comprises a contraction section, a throat section and a diffusion section along the flowing direction of air in the venturi structure, and the air flow guide outer cylinder is provided with a smoke circulation opening at the throat section. The flue gas internal circulation combustor can strengthen the flue gas internal circulation effect, promotes the mixing of fuel gas, combustion-supporting air and flue gas, and does not need to be additionally provided with a flue gas external circulation pipeline.)

1. An internal flue gas recirculation burner, comprising:

an ignition gun;

the primary gas pipe is provided with a primary gas spray head and is arranged outside the ignition gun along the radial direction;

the secondary gas pipe is provided with a secondary gas spray head and is arranged on the outer side of the primary gas pipe along the radial direction;

the air diversion inner cylinder is arranged between the primary fuel gas pipe and the secondary fuel gas pipe along the radial direction;

the air diversion outer cylinder is arranged on the outer side of the air diversion inner cylinder along the radial direction;

the air diversion inner cylinder and the air diversion outer cylinder form a venturi structure, the venturi structure sequentially comprises a contraction section, a throat section and a diffusion section along the flowing direction of air in the venturi structure, and the air diversion outer cylinder is provided with a smoke circulation opening at the throat section.

2. The internal flue gas recirculation burner of claim 1, wherein the primary gas tube extends beyond the secondary gas tube in an axial direction such that the primary gas burner tip is located downstream of the throat section of the venturi structure in the axial direction and the secondary gas burner tip is located upstream of the throat section of the venturi structure in the axial direction.

3. The in-flue gas recirculation burner of claim 1, comprising a flame tube assembly including the air guide outer cylinder and a flame tube disposed outside the air guide outer cylinder in a radial direction, the flame tube being provided with a flue gas recirculation groove, the flue gas recirculation groove of the flame tube being disposed at a position corresponding to a position of the flue gas recirculation opening of the air guide outer cylinder.

4. The in-flue gas recirculation burner of claim 1, comprising a flame holder assembly comprising the air guiding inner barrel and a flame holder disposed radially inside the air guiding inner barrel.

5. The internal flue gas circulation burner of claim 1, further comprising a gas channel outer sleeve and a gas channel inner sleeve, wherein the burning torch is disposed inside the gas channel inner sleeve in a radial direction, the primary gas pipe is disposed between the gas channel outer sleeve and the gas channel inner sleeve in the radial direction, and the secondary gas pipe is disposed outside the gas channel outer sleeve in the radial direction.

6. The flue gas internal circulation burner of claim 1, wherein the flue gas circulation openings of the air guide outer cylinder are arranged obliquely according to the flow direction of air in the venturi structure.

7. The internally circulating flue gas burner of claim 3, wherein the flue gas circulation slots of the liner extend in an axial direction from the beginning of the venturi structure beyond the axial location of the flue gas circulation openings of the air guide outer barrel.

8. The internally circulating flue gas burner of claim 1, wherein the axis of the flue gas circulating opening of the air guide outer cylinder forms an angle of 30 ° to 60 ° with the central axis of the burner.

9. The intradfume recirculation burner of claim 3, wherein the ratio of the diameter of the throat section of the venturi structure to the radius of the flame tube is 0.09-0.18.

10. The intradfume recirculation burner of claim 3, wherein the ratio of the length of said throat section of said venturi structure to the radius of said flame tube is 0.013-0.25.

11. The in-flue gas recirculation burner of claim 3, wherein the ratio of the width of the flue gas recirculation opening of the air guide outer cylinder to the radius of the flame tube is 0.02-0.05.

12. The in-flue gas recirculation burner of claim 3, wherein the ratio of the flue gas recirculation slots of the flame tube to the radius of the flame tube is 0.3-0.45.

13. The flue gas internally circulating combustor of claim 1, wherein the portion of the air guiding inner barrel forming the diffuser section is inclined toward a central axis of the combustor by an angle of 10 ° to 20 °.

14. The intrados flue gas combustor of claim 3, wherein the air guide inner barrel comprises a straight extension that abuts the portion of the air guide inner barrel that forms the constrictor.

15. The in-flue gas recirculation burner of claim 14, wherein the ratio of the flat extension length to the flame tube radius is 0.06-0.13.

16. The flue gas internally circulating combustor of claim 14, wherein the ratio of the air flow width inside the straight extension of the air guiding inner barrel to the radius of the flame tube is 0.18-0.25.

Technical Field

The invention relates to the technical field of burners, in particular to a flue gas internal circulation burner.

Background

With the vigorous implementation of the policy of energy conservation and emission reduction in China, the NOx emission standard of a gas burner is reduced to 30mg/Nm³. The low-nitrogen modification project in the whole country is steadily developed, and the adopted low-nitrogen burners mainly comprise a surface burner, a flue gas external circulation low-nitrogen burner and the like. The surface burner mostly adopts a larger excess air coefficient to reduce NOx emission, and the thermal efficiency of the burner is influenced to a certain extent. The flue gas extrinsic cycle low NOx burner is then through increasing the flue gas extrinsic cycle pipeline, mixes partial flue gas and combustion-supporting air mutually and realizes the low NOx burning, and not only whole equipment is more complicated, and flue gas circulating line's comdenstion water problem also is difficult to solve.

Based on the industrial application background of the low-nitrogen burner, in order to practically and effectively solve the technical defects of the current low-nitrogen combustion, a flue gas internal circulation technology is provided, namely, the low-nitrogen burner which does not adopt the form of excess air or a flue gas external circulation pipeline is adopted, and a self-flue gas circulation process is realized in a hearth, so that the aim of reducing the oxygen content of combustion-supporting air and further reducing the emission of NOx is achieved. For the flue gas internal circulation combustor, how to strengthen the flue gas internal circulation effect and promote the mixing of fuel gas, combustion air and flue gas are the key points for reducing the NOx emission.

Therefore, there is a need to provide a flue gas internal circulation combustor to at least partially solve the above problems.

Disclosure of Invention

In this summary, concepts in a simplified form are introduced that are further described in the detailed description. This summary of the invention is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

To at least partially solve the above problems, the present invention provides a flue gas internal circulation burner comprising:

an ignition gun;

the primary gas pipe is provided with a primary gas spray head and is arranged outside the ignition gun along the radial direction;

the secondary gas pipe is provided with a secondary gas spray head and is arranged on the outer side of the primary gas pipe along the radial direction;

the air diversion inner cylinder is arranged between the primary fuel gas pipe and the secondary fuel gas pipe along the radial direction;

the air diversion outer cylinder is arranged on the outer side of the air diversion inner cylinder along the radial direction;

the air diversion inner cylinder and the air diversion outer cylinder form a venturi structure, the venturi structure sequentially comprises a contraction section, a throat section and a diffusion section along the flowing direction of air in the venturi structure, and the air diversion outer cylinder is provided with a smoke circulation opening at the throat section.

Optionally, the primary gas tube extends beyond the secondary gas tube in an axial direction, such that the primary gas burner cap is located at a downstream position of the throat section of the venturi structure in the axial direction, and the secondary gas burner cap is located at an upstream position of the throat section of the venturi structure in the axial direction.

Optionally, the flue gas internal circulation combustor comprises a flame tube assembly, the flame tube assembly comprises the air guide outer cylinder and a flame tube arranged outside the air guide outer cylinder along the radial direction, the flame tube is provided with a flue gas circulation groove, and the flue gas circulation groove of the flame tube is arranged at a position corresponding to the position of the flue gas circulation opening of the air guide outer cylinder.

Optionally, the flue gas inner circulation combustor comprises a flame stabilizing disc assembly, and the flame stabilizing disc assembly comprises the air guide inner cylinder and a flame stabilizing disc arranged on the inner side of the air guide inner cylinder along the radial direction.

Optionally, the flue gas internal circulation combustor further includes a gas channel outer sleeve and a gas channel inner sleeve, the burning torch is arranged inside the gas channel inner sleeve along the radial direction, the primary gas pipe is arranged between the gas channel outer sleeve and the gas channel inner sleeve along the radial direction, and the secondary gas pipe is arranged outside the gas channel outer sleeve along the radial direction.

Optionally, the flue gas circulation opening of the air guide outer cylinder is obliquely arranged according to the flowing direction of air in the venturi structure.

Optionally, the flue gas circulation groove of the flame tube extends from the starting end of the venturi structure in the axial direction beyond the axial position of the flue gas circulation opening of the air diversion outer cylinder.

Optionally, an included angle between an axis of the flue gas circulation opening of the air diversion outer cylinder and a central axis of the burner is 30 ° to 60 °.

Optionally, the ratio of the diameter of the throat section of the venturi structure to the radius of the flame tube is 0.09-0.18.

Optionally, a ratio of a length of the throat section of the venturi structure to a radius of the flame tube is 0.013-0.25.

Optionally, the ratio of the width of the flue gas circulation opening of the air guide outer cylinder to the radius of the flame tube is 0.02-0.05.

Optionally, the ratio of the flue gas circulation groove of the flame tube to the radius of the flame tube is 0.3-0.45.

Optionally, a portion of the air guiding inner barrel forming the diffuser section is inclined toward a central axis of the combustor at an angle of 10 ° to 20 °

Optionally, the air guide inner barrel comprises a straight extension, and the straight extension is adjacent to the part of the air guide inner barrel forming the contraction section.

Optionally, the ratio of the flat extension length to the radius of the flame tube is 0.06-0.13.

Optionally, the ratio of the air circulation width inside the straight extension section of the air guide inner cylinder to the radius of the flame tube is 0.18-0.25.

According to the flue gas internal circulation combustor, the air guide outer cylinder and the air guide inner cylinder are arranged and matched to form a Venturi structure, so that the flue gas internal circulation effect can be enhanced, and the mixing of fuel gas, combustion-supporting air and flue gas is promoted; the smoke external circulation pipeline does not need to be additionally arranged, and the problem of condensed water is avoided; the low-nitrogen burner equipment can be simplified; the running cost and the risk of the combustor can be reduced; the combustion efficiency of the boiler is ensured; effectively ensure that NOx emissions are reduced to 30mg/Nm with the beneficial effects described above³。

Drawings

The following drawings of embodiments of the invention are included as part of the present invention for an understanding of the invention. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings, there is shown in the drawings,

FIG. 1 is a cross-sectional side view of a flue gas internal circulation combustor according to an embodiment of the present invention;

FIG. 2 is a front view of a flue gas internal circulation combustor according to an embodiment of the present invention;

FIG. 3 is a partial cross-sectional side view of an in-flue gas recirculation combustor according to an embodiment of the present invention.

Detailed Description

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that embodiments of the invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in detail so as not to obscure the embodiments of the invention.

In the following description, a detailed structure will be presented for a thorough understanding of embodiments of the invention. It is apparent that the implementation of the embodiments of the present invention is not limited to the specific details familiar to those skilled in the art.

The invention provides a flue gas internal circulation combustor. As shown in fig. 1 and 2, the flue gas internal circulation combustor includes: the gas burner comprises an ignition gun 1, a gas channel assembly 2, a burner mounting flange 3, a flame tube assembly 4 and a flame stabilizing disc assembly 5. The ignition gun 1 has an ignition function; the gas channel assembly 2 comprises a gas channel outer sleeve 21, a gas channel inner sleeve 22, a gas pipe positioning piece 23, a first-stage/inner-ring gas pipe provided with a first-stage/inner-ring gas nozzle 25, and a second-stage/outer-ring gas pipe which is positioned at the outer side of the first-stage/inner-ring gas pipe along the radial direction and is provided with a second-stage/outer-ring gas nozzle 24, wherein the first-stage/inner-ring gas nozzle 25 and the second-stage/outer-ring gas nozzle 24 can realize fuel staged combustion; the combustor mounting flange 3 is used for equipment mounting; the flame tube assembly 4 comprises a flame tube mounting flange 41, a flame tube 42 and an air guide outer cylinder 43, and is mainly used for guiding combustion-supporting air and providing a flue gas inner circulation path; the flame stabilizing disc assembly 5 comprises an air guide inner cylinder 51, a flame stabilizing disc fixing part 52 and a flame stabilizing disc 53, and is mainly used for stabilizing flame, realizing reasonable proportion of combustion air and promoting internal circulation of flue gas.

The air guide inner cylinder 51 and the air guide outer cylinder 43 form a venturi structure, the venturi structure sequentially comprises a contraction section, a throat section and a diffusion section along the flowing direction of air in the venturi structure (from right to left as shown in fig. 1), and the air guide outer cylinder is provided with a plurality of smoke circulation openings at the throat section. When combustion-supporting air flows through the Venturi structure, the flow velocity of the air is increased due to the fact that the flow cross section area of the contraction section is gradually reduced, and the air is accelerated to reach the maximum velocity at the throat section, so that the internal pressure of the Venturi structure at the throat section is minimum, smoke which is beneficial to external backflow flows into the Venturi structure through the smoke circulation opening arranged at the throat section (the smoke amount can reach 10% -12% of the air amount), the smoke internal circulation effect is enhanced, and mixing of gas, combustion-supporting air and smoke is promoted.

According to the gas internal circulation combustor of the invention, the primary gas pipe extends beyond the secondary gas pipe along the axial direction, so that the primary gas nozzle 25 is located at the downstream position of the throat section of the venturi structure along the axial direction (as shown in fig. 1, the primary gas nozzle 25 extends beyond the terminal end of the diffuser section of the venturi structure along the axial direction), and the secondary gas nozzle 24 is located at the upstream position of the throat section of the venturi structure along the axial direction (as shown in fig. 1, the secondary gas nozzle 24 is located at the convergent section of the venturi structure along the axial direction). A plurality of first-stage/inner ring gas pipes and a plurality of second-stage/outer ring gas pipes are arranged along the circumferential direction, so that flame segmentation is realized. Set up a plurality of inner circle gas pipes and a plurality of outer lane gas pipes respectively and make outer lane gas pipe contract for inner circle gas pipe along axial direction, can strengthen the effect of staged combustion and strengthen the co-combustion of backward flow flue gas and combustion air.

According to the flue gas internal circulation burner, the flame tube 42 is arranged outside the air guide outer cylinder 43 along the radial direction, and the flame tube 42 and the air guide outer cylinder 43 can be integrally formed. The flame tube 42 is provided with a plurality of flue gas circulation grooves, as shown in fig. 3, the flue gas circulation grooves of the flame tube are arranged at positions corresponding to the positions of the flue gas circulation openings of the air guide outer cylinder. This arrangement helps to mix a portion of the flue gas generated by combustion with the combustion air by passing through the flue gas circulation slots of the flame tube and the flue gas circulation openings of the air guide outer cylinder into the venturi structure formed by the air guide outer cylinder 43 and the air guide inner cylinder 51, and a portion of the returned flue gas can be mixed with the fuel gas sprayed from the secondary fuel gas nozzle 24 in the area between the flame tube 42 and the air guide outer cylinder 43 (as shown in fig. 1). Thereby enhancing the mixing effect of the fuel gas, the combustion air and the flue gas. A plurality of flue gas circulation grooves are formed in the flame tube 4.2, and can inject and reflux flue gas, so that a path is provided for flue gas circulation; the air guide outer cylinder 43 is provided with a plurality of flue gas circulation openings, so that the flue gas internal circulation effect can be enhanced under the action of the Venturi effect.

The flame stabilizing disc 53 is arranged at the inner side of the air guide inner cylinder 51 along the radial direction and is positioned at a position approximately flush with the terminating end of the diffusion section of the Venturi structure along the axial direction, and the flame stabilizing disc 53 and the air guide inner cylinder 51 can be integrally formed. The flame stabilizing disc 53 is provided with a blade structure, so that air swirl can be realized, and a flame stabilizing effect is achieved.

According to the internal circulation combustor for flue gas of the present invention, as shown in fig. 1, the ignition gun 1 is disposed inside the gas channel inner sleeve 22 in the radial direction, the primary gas pipe is disposed between the gas channel outer sleeve 21 and the gas channel inner sleeve 22 in the radial direction, and the secondary gas pipe is disposed outside the gas channel outer sleeve 21 in the radial direction. The gas channel assembly 2 of the invention can rationalize the internal and external proportion of the gas by changing the number and the sectional area of the gas pipes of the inner and outer rings.

As shown in fig. 1, the primary gas nozzle 25 penetrates through the flame stabilizing disc 53 in the axial direction, so that the gas ejected from the primary gas nozzle 25 can be mixed with the combustion air flowing out through the air swirling action of the flame stabilizing disc 53.

As shown in fig. 3, the flue gas circulation opening of the air guide outer cylinder 43 is arranged obliquely according to the flow direction of air in the venturi structure, i.e. the flue gas circulation opening is located at the port of the outer side wall of the air guide outer cylinder and is closer to the contraction section than the port of the inner side wall. The arrangement helps to guide the backflow flue gas into the venturi structure formed by the air guide outer cylinder and the air guide inner cylinder under the action of air flow in the venturi structure. Preferably, an included angle theta between the axis of the flue gas circulation opening of the air diversion outer cylinder and the central axis of the combustor is 30-60 degrees

As shown in fig. 3, the flue gas circulation groove of the flame tube 42 extends from the starting end of the venturi structure (the starting end of the contraction section) in the axial direction beyond the axial position of the flue gas circulation opening of the air guide outer cylinder 43. This arrangement ensures that sufficient quantity of the recirculated flue gas enters the area between the liner 42 and the air guide outer cylinder 43.

As shown in fig. 1 and 3, the diffuser-forming portion of the air guide inner cylinder 51 is inclined (inwardly inclined) toward the central axis of the combustor, and the diffuser-forming portion of the air guide outer cylinder 43 extends parallel to the central axis of the combustor. This arrangement helps to guide the mixed gas of combustion air and return flue gas flowing out via the venturi structure toward the position where the primary gas shower nozzle 25 is directed, thereby achieving mixed combustion with the gas jetted from the primary gas shower nozzle 25.

As shown in fig. 1 and 3, the air guide inner cylinder 51 is provided at its starting end forming the venturi structure with a straight extension adjacent to the portion of the air guide inner cylinder forming the constriction, thereby dividing the combustion air into a portion directed into the venturi structure and another portion directed toward the flame stabilizing disk along the primary/inner ring gas pipe, thereby achieving a rational ratio of the combustion air of the inner and outer rings.

According to the embodiment of the invention, as shown in FIG. 3, for the flue gas internal circulation combustor with the radius of a flame tube R, the air flow passing width D1 on the inner side of the air guide inner cylinder is (0.18-0.25) R, the width D2 of the Venturi structure throat section is (0.09-0.18) R, and the opening width D3 of the flue gas circulation groove of the air guide outer cylinder is (0.02-0.05) R. The length L1 of the straight extension section of the air guide inner cylinder is (0.06-0.13) R, the length L2 of the venturi structure throat opening section is (0.013-0.25) R, and the inward inclination angle of the venturi structure diffuser section (the air guide inner cylinder) isIs 10 degrees to 20 degrees, and the width L3 of the flame tube flue gas circulating groove is (0.3-0.45) R.

According to a preferred embodiment of the invention, taking a 1.5MW flue gas internal circulation combustor as an example, the radius of the flame tube is 160mm, the air circulation width D1 inside the air guide inner cylinder is 36.5mm, the width D2 of the venturi structure throat section is 20mm, the opening width D3 of the flue gas circulation groove of the air guide outer cylinder is 4mm, and the angle theta is 45 degrees. The length L1 of the straight extension section at the rear end of the air guide inner cylinder is 10mm, the length L2 of the throat section of the Venturi structure is 20mm, and the inward inclination angle of the diffusion section (the air guide inner cylinder) of the Venturi structureIs 10 degrees, and the width L3 of the flame tube flue gas circulating groove is 60 mm.

The flue gas internal circulation combustor provided by the invention injects flue gas in a flue gas internal circulation mode, so that the oxygen concentration in combustion air is reduced, and the thermal NOx generation is reduced jointly by optimizing the mixing effect of the gas in the inner ring and the outer ring and the combustion air in proportion. The flue gas internal circulation combustor can realize the flue gas circulation of the combustor without a flue gas external circulation pipeline, and the NOx emission is controlled to be 30mg/Nm³The following.

Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Terms such as "disposed" and the like, as used herein, may refer to one element being directly attached to another element or one element being attached to another element through intervening elements. Features described herein in one embodiment may be applied to another embodiment, either alone or in combination with other features, unless the feature is otherwise inapplicable or otherwise stated in the other embodiment.

The present invention has been described in terms of the above embodiments, but it should be understood that the above embodiments are for purposes of illustration and description only and are not intended to limit the invention to the scope of the described embodiments. It will be appreciated by those skilled in the art that many variations and modifications may be made to the teachings of the invention, which fall within the scope of the invention as claimed.