CN113124400A - Burner and method of combustion - Google Patents

Abstract

The present application provides a combustor and a method of combustion. Wherein, this combustor includes: a housing defining an inner chamber located inside the housing and an outer chamber located outside the housing, the housing having one or more passages disposed therein, the passages configured to place the inner chamber and the outer chamber in fluid communication; an elongated lamp connected to a first air source and a first fuel source, and an outlet end of the elongated lamp disposed in the interior cavity and adjacent the passageway; and a plurality of fuel tubes, an inlet end of the plurality of fuel tubes being attached to the second fuel source, and outlet ends of the fuel tubes all being disposed in the outer chamber; wherein the inner chamber is further connected to a second air source. The combustor and the combustion method have the advantages of simple structure, easiness in manufacturing, convenience in installation and the like, the combustion performance and maintainability of the combustor can be improved, and the emission of nitrogen oxides is reduced.

Description

Burner and method of combustion

Technical Field

The present application relates to the structure and operation of low NOx burners. More specifically, the present application relates to a combustor intended to provide staged combustion including premixing. The application also relates to a combustion method using the burner.

Background

As is known, burners are widely used in industrial plants to provide heat. However, nitrogen oxides may be produced during the combustion process. As legislative regulations in environmental terms are becoming stricter, it is desirable that the burner be able to provide as low a nitrogen oxide emission as possible. It has been established that the formation of nitrogen oxides can be reduced by lowering the flame temperature of the burner. To facilitate the reduction of flame temperature, some existing burners employ staged combustion. That is, combustion is not performed with a single large flame, but rather in relatively small flames divided into multiple stages. More staged combustion can reduce nox emissions while also reducing flame stability.

In order to minimize the emission of nitrogen oxides, it is desirable to increase the proportion of staged combustion as much as possible. However, existing combustor designs fail to achieve the above-mentioned expectations.

There is therefore a continuing need for new combustor and combustion method solutions that are capable of alleviating the above-mentioned problems, at least to some extent.

Disclosure of Invention

An object of an aspect of the present application is to provide a combustor which is intended to improve combustion performance of the combustor and increase a fuel staging ratio of the combustor to reduce emission of nitrogen oxides. Another object of the present application is to provide a combustion method using the above burner.

The purpose of the application is realized by the following technical scheme:

a burner, comprising:

a housing defining an inner chamber located inside the housing and an outer chamber located outside the housing, the housing having one or more passages disposed therein, the passages configured to place the inner chamber and the outer chamber in fluid communication;

an elongated lamp connected to a first air source and a first fuel source, and an outlet end of the elongated lamp disposed in the interior cavity; and

a plurality of fuel tubes having their inlet ends attached to the second fuel source and their outlet ends all disposed in the outer chamber;

wherein the inner chamber is further connected to a second air source.

In the above burner, optionally, the pilot light comprises a pilot light, and air from a first air source is mixed with a first fuel from a first fuel source via a venturi.

In the above burner, optionally, the outlet end of the pilot lamp includes a plurality of manifolds, the outlet ends of the manifolds being respectively disposed adjacent to and upstream of the channels so that the flame from the outlet ends can reach the channels.

In the above burner, optionally, the outlet end of each manifold is provided with a flame holder, respectively.

In the above burner, optionally, the outlet end of the fuel pipe is disposed upstream of the passage.

In the above burner, optionally, a plurality of radial passages extend radially along the same cross-section of the casing and communicate to the flame holding ring, and a plurality of axial passages extend from the plurality of radial passages to the tip end of the casing.

In the above burner, optionally, the housing is configured to extend in an axial direction, and the passages include a plurality of radial passages and a plurality of axial passages, wherein each axial passage is in fluid communication with at least one radial passage, respectively.

In the above burner, optionally, a damper is provided on the second air source, the damper having a handle to control the flow of air.

In the above burner, optionally, the housing is attached to the windbox and the second air source is in fluid communication with the windbox, the incandescent lamp being mounted to the windbox by a removable cap such that the incandescent lamp passes through the windbox and extends into the internal cavity.

A combustion method using the above burner, comprising the steps of:

1) premixing air from a first air source and a first fuel from a first fuel source in an incandescent lamp;

2) igniting the mixed gas at the exit end of the pilot burner such that the flame passes through the passageway into the outer chamber; and is

3) A second fuel is delivered through the fuel tube and is combusted by the flame at the outer chamber.

The combustor and the combustion method have the advantages of simple structure, easiness in manufacturing, convenience in use and the like, the combustion performance and maintainability of the combustor can be improved, and the emission of nitrogen oxides is reduced.

Drawings

The present application will be described in further detail below with reference to the drawings and preferred embodiments, but those skilled in the art will appreciate that the drawings are only drawn for the purpose of illustrating the preferred embodiments and therefore should not be taken as limiting the scope of the present application. Furthermore, unless specifically stated otherwise, the drawings are intended to be conceptual in nature or configuration of the described objects and may contain exaggerated displays and are not necessarily drawn to scale.

FIG. 1 is a cross-sectional schematic view of an embodiment of the combustor of the present application as installed.

Fig. 2 is a partial cross-sectional perspective view of the embodiment shown in fig. 1.

Detailed Description

Hereinafter, preferred embodiments of the present application will be described in detail with reference to the accompanying drawings. Those skilled in the art will appreciate that the descriptions are illustrative only, exemplary, and should not be construed as limiting the scope of the application.

First, it should be noted that the terms top, bottom, upward, downward and the like are defined relative to the directions in the drawings, and they are relative terms, and thus can be changed according to the different positions and different practical states in which they are located. These and other directional terms should not be construed as limiting terms.

Furthermore, it should be further noted that any single technical feature described or implied in the embodiments herein, or any single technical feature shown or implied in the figures, can still be combined between these technical features (or their equivalents) to obtain other embodiments of the present application not directly mentioned herein.

It should be noted that in different drawings, the same reference numerals indicate the same or substantially the same components.

FIG. 1 is a cross-sectional schematic view of an embodiment of the combustor of the present application as installed. The burner 100 according to an embodiment of the present application includes: a housing 110, a bellows 120, a beacon 130, and a plurality of fuel tubes 140.

The housing 110 may be formed from refractory brick and extends generally along an axis and forms a frustoconical structure. The side of the housing 110 may be configured with a step for accommodating the fuel pipe 140. The interior of the housing 110 defines an inner cavity 110a and the exterior of the housing 110 forms an outer cavity 110 b. The housing 110 terminates with an opening and the inner chamber 110a is in fluid communication with the outer chamber 110b at the opening. The other end of the housing 110 is attached to the bellows 120, and the internal cavity 110a is in fluid communication with the interior of the bellows.

A plurality of passages may be provided in the housing 110, each of which communicates between the inner chamber 110a and the outer chamber 110 b. In the illustrated embodiment, the housing 110 includes a plurality of radial passages 112 extending in a radial direction, and a plurality of axial passages 113 extending in an axial direction. Wherein each axial passage extends from each radial passage 112 to the end of the housing 110. In another embodiment, the radial channels 112 and the axial channels 113 may not be limited to a one-to-one correspondence. For example, a single radial passage may communicate with two or more axial passages, or a single axial passage may communicate with two or more radial passages.

As used herein, the axial direction refers to a direction in which the axis of symmetry of the housing 110 is located, and the radial direction refers to a direction in which a ray, on a perpendicular plane to the axis of symmetry of the housing 110, from an intersection of the perpendicular plane and the axis of symmetry is directed.

The radial passage 112 and the axial passage 113 may be disposed near the opening of the housing 110 so that a flame can extend through the radial passage 112 and the axial passage 113. In one embodiment of the present application, eight radial channels 112 and corresponding eight axial channels 113 are provided in the housing 110. However, more or less than eight radial channels 112 and axial channels 113 may be provided, as desired.

The bellows 120 is attached at the upstream end of the housing 110 and includes an interior space in fluid communication with the inner cavity 110 a. A damper 121 is provided on the windbox 120, the damper 121 being connected to a second air source, not shown. Thus, the interior chamber 110a is indirectly connected to the second air source through the blower 120 and the damper 121. The second air source is used to provide air for combustion to facilitate combustion of the fuel as described in more detail below.

The dampers 121 may be disposed laterally or radially of the windbox 120 as shown, or may be disposed at other positions as needed. For example, the damper 121 may be provided at the bottom of the windbox 120, or in the axial direction of the windbox 120.

Air may also be any gas known to those skilled in the art for promoting combustion, including but not limited to air obtained directly from the surrounding atmosphere, or combustion promoting gases from other sources, such as pure oxygen, etc.

A handle 122 may be provided to the damper 121 to adjust the flow rate of air entering the damper 121.

The beacon 130 may be attached to the detachable cap 123, and the detachable cap 123 is mounted on one end of the bellows 120 such that the beacon 130 is disposed substantially in the axial direction and extends through the bellows 120 and the housing 110. The beacon 130 has a generally tubular structure and is attached to a first air source and a first fuel source, not shown. The first air source is used to provide premixed combustion air and the first fuel source is used to provide the first fuel required for combustion, which may be, for example, natural gas or any suitable combustible substance.

In one embodiment of the present application, the upstream end of the pilot light 130 is provided with a venturi or venturi structure 131. A first air source and a first fuel source are attached to the two primary fluid inlets of the venturi 131, respectively. For example, a first fuel source may be attached to the fuel nozzle of the venturi 131, the injection of the first fuel out of the fuel nozzle entraining combustion air such that the first fuel is premixed with combustion air from the first air source. In one embodiment of the present application, the fuel nozzle of the venturi 131 may have a diameter of approximately 1.6 mm.

The first source of air may be air drawn from the ambient environment, but may also be any suitable source of combustion supporting gas. According to actual needs, the first air source can also be provided with components such as an air supply device, an air duct and the like.

The downstream end of the pilot lamp 130 extends into the interior cavity 110a of the housing 110 and the outlet end of the pilot lamp 130 is disposed adjacent to each of the radial and axial passages 112, 113. For example, in the illustrated embodiment, a plurality of manifolds 132 are provided at the downstream or outlet end of the pilot lamp 130. Each manifold 132 may be disposed proximate to a channel on housing 110, such as proximate to radial channel 112 or proximate to flame holder ring 112 a. As shown, the downstream end of each manifold 132 may be disposed upstream of the channels and adjacent to the inner surface of the housing 110, and the distance between the downstream end of each manifold 132 and the channels is such that the flame can reach or pass through the channels. The downstream end of each manifold 132 may also be equipped with a flame holder, and the radially and axially extending portions of the manifolds 132 are configured with a predetermined angle therebetween such that the downstream end of the manifold 132 faces or is disposed adjacent to the flame holding ring 112a such that the burning flame can reach the flame holding ring 112 a.

Premixed combustion air and first fuel from the pilot burner 130 exit through the downstream end of the manifold 132 and combust to form a flame at the manifold 132. The flame holding ring 112a directs the flame into the radial passage 112 and the axial passage 113, and the flame is able to pass through the radial passage 112 and the axial passage 113 and extend into the outer cavity 110 b. Thus, a series of axial flames and a series of radial flames in the outer chamber 110b are formed at the downstream end of the housing 110, facilitating further combustion operations in the outer chamber 110 b.

By providing the detachable cover 123 and the connection structure of the beacon light 130, the beacon light 130 can be easily detached and taken out from the inside of the case 110 and the bellows 120 for inspection, maintenance, replacement, and the like. As shown, the cap 123 may be provided in a generally axial arrangement about the housing 110 and removably attached to the upstream end of the windbox 120 by a plurality of bolt and nut combinations.

As used herein, an upstream end refers to a location closer to the fluid supply source, and a downstream end refers to a location further from the fluid supply source. In the embodiment shown in fig. 1, the fluid flows generally from the bottom of fig. 1 toward the top of fig. 1, i.e., the position closer to the top in fig. 1 is the downstream end and the position closer to the bottom is the upstream end.

The downstream or outlet end of manifold 132 may include one or more nozzles to enable the mixed gas to be output therefrom. The nozzles may be arranged at the side of the flame holder or in the radial direction and the end of the flame holder may also be provided with an outlet. The nozzles may be configured to face in a radial direction, or in a direction toward the flame holding ring 112a and the radial passage 112.

A plurality of fuel tubes 140 are disposed around the housing 110 outside the housing 110. The downstream or outlet end of each fuel tube 140 is disposed in the outer chamber 110b, generally facing in the axial direction, and is located at a position upstream of the passageways. As shown, the fuel tubes 140 extend through the housing 110 and the windbox 120 and all the way to the fuel manifold 141 at the upstream end of the windbox 120. The fuel manifold 141 may be attached to a second fuel source, not shown, and thus the inlet end of the fuel tube 140 is attached to the second fuel source, not shown. In use, a second fuel from a second fuel source is delivered along the fuel tube 140 into the outer chamber 110 b. In addition, air from a second air source is also delivered into the outer chamber 110b through the downstream end of the housing 110. The secondary fuel and air mix in the outer chamber 110b and are ignited and combusted via the flame from the passageway. Air from the second air source can also participate in the combustion that takes place at the manifold 132 of the pilot lamp 130.

The tip of the fuel pipe 140 may be disposed at a step on the outer surface of the housing 110 and extend from the step into the outer cavity 110 b. Each of the fuel tubes 140 may be arranged to be disposed substantially symmetrically about the axial direction of the casing 110. In the illustrated embodiment, four fuel tubes 140 are symmetrically disposed about the periphery of the housing 110. More or less than four fuel tubes may be disposed around the perimeter of the housing 110, as desired.

The secondary fuel delivered by the fuel line may be any material suitable for combustion, including but not limited to natural gas and the like. The second fuel may be of the same composition as the first fuel or may be provided as a different composition as desired.

In contrast to the prior art burner arrangements, embodiments of the present application provide all of the outlet ends of the fuel tubes in the outer chamber, thereby eliminating the fuel tubes disposed in the inner chamber. Thus, all of the second fuel is fed to the outer chamber for combustion, so that a proportion of 100% of staged combustion is achieved. Higher proportions of staged combustion can reduce nitrogen oxide emissions.

Fig. 2 is a partial cross-sectional perspective view of the embodiment shown in fig. 1. As shown, each radial passage 112 is disposed in the same cross-section near the end of the housing 110, and forms an annular recess on the cross-section at the inner wall of the housing 110, the annular recess forming a flame holding ring 112 a. As shown, the downstream end of each manifold 132 is disposed adjacent to the flame holding ring 112 a. It can also be seen in connection with fig. 1 and 2 that the inner wall of the casing 110 may be provided with a radially inwardly projecting annular portion at a downstream portion of the flame holding ring 112a to direct the flame in the direction of the radial channels 112 and the axial channels 113. Further, the exterior of the housing 110 may provide a recess for receiving the fuel tube 140.

In the illustrated embodiment, four manifolds 132 are provided at the downstream end of the pilot lamp 130, eight radial channels 112 and eight axial channels 113 are provided in the housing 110, respectively, and four fuel tubes 140 are provided at the outer cavity, respectively. However, a different number of manifolds, radial channels and axial channels may be provided, according to the actual needs. In the illustrated embodiment, five radial channels 112 and axial channels 113 are exemplarily shown on the housing 110.

In use, combustion air from a first air source is premixed with a first fuel from a first fuel source via a venturi 131 inside an incandescent lamp or lamp 130 to obtain a mixed gas. The mixture is ignited at a manifold 132 at the downstream end of the pilot lamp 130. The flame produced by ignition extends into the outer chamber 110b by means of the flame holding ring 112a, the radial passages 112 and the axial passages 113 for combustion by fuel from the fuel tube 140. Due to the premixing of the mixed gases, plus the dispersed arrangement of the fuel tubes 140 and the various passages. Compared with the burner in the prior art, the burner according to the embodiment of the application can reduce the fuel heat load of the inner cavity so as to reduce the flame temperature and further reduce the emission of nitrogen oxides.

The venturi 131 is also schematically shown in fig. 2. For the sake of clarity, the position of the bellows 120 is not shown in FIG. 2. As will be readily understood in connection with fig. 1, the venturi 131 is disposed outside the windbox 120.

The present application therefore also provides a combustion method carried out using the above-mentioned burner, comprising the steps of:

1) premixing air from a first air source and a first fuel from a first fuel source in an incandescent lamp;

2) igniting the mixed gas at the end of the pilot burner such that the flame passes through the passageway into the outer chamber; and is

3) A second fuel is delivered through the fuel tube and ignited by a flame at the outer chamber for combustion.

By adopting the burner and the burning method, the staged burning of which the outer cavity accounts for 100 percent can be realized, and meanwhile, the good flame stability is kept. According to one embodiment of the present application, the nitrogen oxide content produced by the burner and combustion method of the present application is about 20mg per cubic meter. Compared with the conventional combustor and combustion method, the combustor and the combustion method can reduce the content of generated nitrogen oxides by at least 30%, thereby being beneficial to meeting the requirements of stricter environmental protection laws and regulations.

This written description discloses the application with reference to the drawings, and also enables one skilled in the art to practice the application, including making and using any devices or systems, selecting appropriate materials, and using any incorporated methods. The scope of the present application is defined by the claims and encompasses other examples that occur to those skilled in the art. Such other examples are to be considered within the scope of protection defined by the claims of this application, provided that they include structural elements that do not differ from the literal language of the claims, or that they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims (10)

1. A burner, comprising:

a housing defining an inner chamber located inside the housing and an outer chamber located outside the housing, the housing having one or more passages disposed therein, the passages configured to place the inner chamber and the outer chamber in fluid communication;

an elongated lamp connected to a first air source and a first fuel source, and an outlet end of the elongated lamp disposed in the interior cavity and adjacent to the passageway; and

a plurality of fuel tubes having their inlet ends attached to a second fuel source and their outlet ends all disposed in the outer chamber;

wherein the inner chamber is further connected to a second air source.

2. The burner of claim 1, wherein in the pilot light, air from the first air source is mixed with a first fuel from the first fuel source via a venturi.

3. The burner of claim 1, wherein the outlet end of the incandescent lamp comprises a plurality of manifolds, the outlet end of each manifold being disposed adjacent to and upstream of the channel, respectively, such that a flame from the outlet end can reach the channel.

4. A burner as claimed in claim 3, wherein each manifold is provided with a flame holder at its outlet end.

5. The burner of claim 1, wherein the outlet end of the fuel tube is disposed upstream of the channel.

6. The burner of claim 6, wherein a plurality of radial passages extend radially along the same cross-section of the housing and communicate to the flame holder ring, and a plurality of axial passages extend from the plurality of radial passages to a tip end of the housing.

7. The combustor as in any one of claims 1-6, wherein the housing is configured to extend in an axial direction and the passage comprises a plurality of radial passages and a plurality of axial passages, wherein each axial passage is in fluid communication with at least one radial passage, respectively.

8. The burner of any of claims 1-6, further comprising a damper disposed on the second air source, the damper having a handle to control air flow.

9. The burner of any one of claims 1-6, wherein the housing is attached to a windbox and the second air source is in fluid communication with the windbox, the beacon lamp being mounted to the windbox by a removable cap such that the beacon lamp passes through the windbox and extends into the internal cavity.

10. A combustion method using the burner according to any one of claims 1 to 9, characterized by comprising the steps of:

1) premixing air from the first air source and a first fuel from the first fuel source in the pilot light;

2) igniting a mixed gas at an exit end of the pilot burner such that a flame enters the outer cavity through the passageway; and is

3) A second fuel is delivered through the fuel tube and is combusted by a flame at the outer chamber.

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