WO2018155735A1

WO2018155735A1 - Composite low-nox burner

Info

Publication number: WO2018155735A1
Application number: PCT/KR2017/001989
Authority: WO
Inventors: 이종태; 박재언
Original assignee: 주식회사 수국
Priority date: 2017-02-23
Filing date: 2017-02-23
Publication date: 2018-08-30
Also published as: CN108738333B; JP2019509451A; JP6595089B2; KR102230908B1; HK1256477A1; KR102230908B9; KR20190087592A; CN108738333A

Abstract

The present invention relates to a composite low-NOx burner for reducing the generation amount of NOx, by implementing a gas staging combustion technique and an internal flue gas recirculation (IFGR) combustion technique in a single burner. According to the present invention, the composite low-NOx burner provided in a burner mounting hole of a combustion chamber comprises: a tube inserted into the burner mounting hole such that the front end thereof is exposed to the combustion chamber, and guiding air to the combustion chamber; and at least one fuel spud provided at the end portion of the tube, having a pipe shape for forming split flames by means of injection of fuel into the combustion chamber, and having a first gas inlet, formed in a partial region of the outer periphery thereof, for allowing combustion gas to flow therethrough, wherein a second gas inlet for allowing the combustion gas mixed in the air inside the tube to flow therethrough is formed on the outer periphery of the tube at the rear of the first gas inlet in the outward direction of the combustion chamber. According to the present invention, the burner according to an improved IFGR technique which enables effective self-recirculation of the combustion gas is merged with a gas staging technique so as to enable the generation amount of NOx to be further lowered than that of a low-NOx burner to which an existing IFGR technique is applied.

Description

Hybrid Low Knox Burner

The present invention relates to a low-nox burner, and more particularly, a hybrid type for reducing NOx generation by implementing a gas staging combustion technology and an internal fluorine gas recirculation (IFGR) combustion technology in one burner. It is about low knox burner.

In general, NOx is fuel NOx produced by oxidizing a nitrogen component chemically bonded to a fuel during combustion, and thermal knox generated by liberation of nitrogen contained in combustion air at a high temperature. Thermal NOx) and prompt NOx, which is rapidly generated when hydrocarbon-based fossil fuels are exposed to high temperatures in high concentrations.

Since NOx has an adverse effect on the atmosphere and human life, low-nox burner technology has been developed for a long time. Divided by generation is as follows.

- under -

First generation: The first generation low knox technology is the air staging technology, which supplies air to the combustion stage by stage to prevent rapid oxidation reaction by fuel in the combustion furnace to lower the temperature of flame and thereby Reduce Thermal Knox

2nd generation: The 2nd generation low-nox technology is a gas staging technology, which is divided into a center part (about 5% to 25%) and an outer part (75% to 95%) to eject gas, and the center part has excess air. In addition, the outer part forms an air shortage state, thereby suppressing the oxidation reaction of the outer part occupying most of the flame so that the flame temperature is not increased, thereby reducing the occurrence of thermal rust. Prompt rust may occur due to an air shortage of the outer flame, but prompt knox generation may be suppressed by ejecting gas into a space having a temperature of 1000 ° C. or less while assisting the flame function from the central flame.

3rd generation: In 3rd generation low-nox technology, IFGR (Internal Flue Gas Recirculation) is typically used as the combustion gas is mixed with flames by allowing the primary combustion combustion gas in the combustion chamber to self-recirculate in the combustion chamber. Drop to reduce thermal rust.

As the third generation low-nox technology, the present applicant has proposed a high-efficiency low-nox type combustion head and a burner using the same as Korean Patent No. 10-1466809. Korean Patent No. 10-1466809 has caused a vortex in the combustion head to improve the mixing characteristics of fuel and air to combust fuel and allow the combustion gas to self-recycle, thereby greatly reducing the generation of rust.

In addition, by applying a gas staging combustion technology to IFGR technology, a low knox burner in combination with generation-specific low knox burners has been proposed as Korean Patent No. 10-1569455.

SUMMARY OF THE INVENTION An object of the present invention is to improve a conventional low knox burner and to provide a low knox burner which further reduces the amount of rust generated by applying a gas staging combustion technology to the improved IFGR technology.

The hybrid low knox burner according to the present invention for achieving the problem to be solved by the present invention is a hybrid low knox burner installed in the burner mounting hole of the combustion chamber, inserted into the burner mounting hole, the tip is exposed to the combustion chamber, A tube for guiding air into the; At least one end of the tube is formed in a pipe shape for forming a split flame by injecting fuel into the combustion chamber, the outer peripheral region of the fuel spud is formed a first gas inlet for the combustion gas inlet; At the first gas inlet, a second gas inlet for inlet of the combustion gas mixed with the air inside the tube is formed at the outer periphery of the tube at the rear side of the combustion chamber.

At the second gas inlet, a combustion gas guide is formed obliquely in the flow direction of air.

The fuel spud branches from the fuel supply line and is spaced apart from the first spud tube and is spaced apart from the first spud tube to form a first gas inlet and inserted into the tube and inserted into the split flame. Forming a second spud tube.

The fuel spud is spaced apart from the first supply pipe and branched from the fuel supply pipe, and spaced apart from the first spud pipe to form a first gas inlet, and arranged outside the tube to form a split flame. It may also include a second spud tube.

An end of the first spud tube is provided with a reduced diameter injection connection for injecting fuel towards the second spud tube. In the second spud tube, the end portion of the first gas inlet side has a diameter extension portion extending in diameter toward the first spud tube.

According to the present invention, it is possible to fuse the gas staging technology to the burner according to the improved IFGR technology in which the self-recirculation of the combustion gas is effectively performed, thereby further reducing the amount of rust generated than the low knox burner to which the conventional IFGR technology is applied.

1 is a side cross-sectional view showing a state where a hybrid low knox burner according to a first embodiment of the present invention is installed in a combustion chamber.

FIG. 2 is a perspective view of a portion of the end of the tube cut in FIG. 1. FIG.

3 is an operational state diagram showing the flow of air, fuel gas and combustion gas in the hybrid low-nox burner according to the first embodiment of the present invention.

4A is a diagram illustrating a gas flow between a fuel nozzle and a diffuser in FIG. 1.

4B is a view illustrating a gas flow when there is a step between the fuel nozzle and the diffuser in FIG. 1.

5 is a flow conceptual diagram of a hybrid low knox burner according to a first embodiment of the present invention.

6 is a side cross-sectional view showing a state in which a hybrid low knox burner according to a second embodiment of the present invention is installed in a combustion chamber.

FIG. 7 is a perspective view of the end portion of the tube in FIG. 6;

8 is a flow conceptual diagram for a hybrid low knox burner according to a second embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this case, the same components in the accompanying drawings are to be noted that the same reference numerals as possible. In addition, detailed descriptions of well-known functions and configurations that may blur the gist of the present invention will be omitted. For the same reason, in the accompanying drawings, some components are exaggerated, omitted or schematically illustrated.

A tube is inserted into one side of the combustion chamber referred to herein to receive fuel and air, and an exhaust pipe is formed on the other side of the combustion chamber to discharge the burned combustion gas. However, since the exhaust pipe and its surrounding structure do not correspond to the main core of the present invention, it is not shown or described in the drawings.

Tubes and burners referred to in this specification may be represented in a conceptual cross-sectional view without omission or description of the components to be added. However, this is omitted for the convenience of explanation and understanding of the present invention, the structure and connection of the tube and the burner according to the embodiment should not be limited by the illustrated drawings and description.

1 is a side cross-sectional view illustrating a state in which a hybrid low knox burner is installed in a combustion chamber according to a first embodiment of the present invention, and FIG. As shown, the hybrid low-nox burner 100 according to the first embodiment of the present invention is inserted into the burner mounting hole HL of the combustion chamber FR and fixedly installed by the mounting plate MP, and the wall WL. Tube 110 for guiding air to the combustion chamber (FR) enclosed by the (), side diameter portion 111, tube 110 having a diameter smaller than the diameter of the tube 110 and formed at the tip of the tube 110 A fuel supply pipe 120 disposed inside the fuel supply pipe 120 for supplying fuel, and an outer periphery of the fuel supply pipe 120 coupled to the tip of the fuel supply pipe 120 so that the outer periphery is disposed away from the inner wall of the tube 110. Radially coupled to the distal end of the diffuser 130 and the fuel supply pipe 120 to diffuse the guided air, the fuel supplied by the fuel supply pipe 120 passes between the inner wall of the tube 110 and the outer periphery of the diffuser 130 It includes a plurality of fuel injection pipe 140 for injecting toward the air.

In addition, at least one end of the tube 110 is provided with a pipe shape for forming a split flame by injecting fuel into the combustion chamber, the outer periphery of the first gas inlet 151 for the combustion gas inlet is formed in the fuel The spud 150 is provided. At the first gas inlet 151, the second gas inlet 112 for inlet of the combustion gas mixed with the air inside the tube 110 is formed at the outer periphery of the tube at the rear of the combustion chamber outside. And a blower 115 coupled to the tube 110 to forcibly supply external air to the inside of the tube 110.

The side diameter portion 111 is formed to be curved while having a gentle slope toward the protrusion 124 of the fuel supply pipe 120 protruding from the diffuser 130. Through this, the air passage toward the diffuser 130 is narrowed in the air supply passage 161 formed at the interval d1 between the outer circumferential edge of the diffuser 130 and the side diameter portion 111, thereby increasing the flow rate of the air. . Air is supplied to the diffuser 130 through the air supply passage 161, and at this time, fuel is injected through the fuel injection pipe 140 to form a flame.

The end of the tube 110 forms a diameter extension 116 that is larger in diameter than the middle portion 114 where the first spud tube, which will be described later, of the fuel spud 150 is disposed. In the second gas inlet 112, a combustion gas guide 113 is formed obliquely in a flow direction of air, and the combustion gas of the combustion chamber is recirculated into the middle part 114 of the tube 110. The combustion gas guide unit 113 is preferably formed in the shape of a nozzle having a smaller diameter at the outlet side than the diameter at the inlet side, so that the combustion gas is introduced into the tube 110.

Inside the fuel supply pipe 120, a central air injection pipe 121 for injecting external air from the tip of the fuel supply pipe 120 in the axial direction S of the fuel supply pipe 120 is disposed. By this central air injection pipe 121, the diameter of the flame is increased by the air to be sprayed to prevent the concentration of the flame in the center of the flame. As a result, the temperature of the flame center is prevented from rising excessively, and the amount of thermal knox produced is reduced. Air through the central air injection pipe 121 is injected into the combustion chamber FR through the air injection hole formed in the center of the diffuser 130, the air injection hole is formed smaller than the inner diameter of the central air injection pipe 121 desirable. As shown in the flow analysis diagram of FIG. 5, the central air injection pipe 121 may be removed.

The diffuser 130 has a disc shape (disc type) and includes a plurality of air holes 131 for injecting air supplied through the air supply passage 161 to the combustion chamber FR. The air hole 131 supplies an air to the center of the flame, or when the diameter of the diffuser 130 increases in accordance with the increase in the burner capacity, to form an auxiliary flame to improve the flame resistance of the flame formed in the diffuser 130 Is prepared to. As the nozzles of the air holes 131 and the fuel injection pipe 140 are arranged at a predetermined angle, the amount and pressure of air discharged from the air holes 131 may have uniformity with respect to the front end of the plate of the diffuser 130. And when mixed with fuel injected from the nozzle, the mixing ratio of fuel and air can also be expected to be uniform.

The fuel injection pipe 140 is disposed radially at the end of the fuel supply pipe 120 and includes a fuel nozzle 141 for ejecting fuel in a direction orthogonal to air supplied through the air supply passage 161. The fuel injected from the fuel nozzle 141 intersects the air discharged through the air supply passage 161 at an angle close to 90 degrees. Accordingly, the fuel is injected and rapidly mixed with the air supplied through the air supply passage 161 to form a flame, and the center is formed by the air guided to the radial center of the combustion chamber FR through the side portion 111. It can form a concentrated flame. At this time, the flame is concentrated to the center, and dispersed to form a long-necked region, the width of the region is narrow, as the pressure is lowered, the combustion gas is guided to the long-necked region, the combustion gas to achieve a self-recirculation.

In the first embodiment, the radial end of the fuel injection pipe 140 and the outer periphery of the diffuser 130 are at the same position as shown in FIG. 4A, but as shown in FIG. 4B, the fuel injection pipe 140 is disposed in the fuel injection pipe 140. In order for the injected fuel to rapidly mix with the air supplied through the air supply passage 161, a gap d2 may be formed between the end of the fuel injection pipe 140 and the edge of the diffuser 130 plate. have. The gap gap d2 may be set to 0.1% to 50% of the diameter of the nozzle of the fuel injection pipe 140.

When the end of the fuel injection pipe 140 is formed smaller than the outer peripheral end of the diffuser 130, air discharged through the air supply passage 161 may cause vortex at the outer peripheral end of the diffuser 130, the air by the vortex And fuel can be mixed more rapidly. This will be described in more detail with reference to FIGS. 4A and 4B.

4A illustrates a case where the length of the fuel injection tube 140 is the same as the outer peripheral end of the diffuser 130, and FIG. 4B illustrates a case where the length of the fuel injection tube 140 does not reach the outer peripheral end of the diffuser 130. In FIG. 4A, since the air discharged from the air supply passage 161 to the combustion chamber has a straightness, no vortex is formed at the end of the fuel injection pipe 140 and a straight airflow flows. On the other hand, referring to Figure 4b, the outer circumferential end of the diffuser 130 and the end of the fuel injection pipe 140 forms a step d2, the air from the air supply passage 161 to the combustion chamber is diffused to the area where the step is generated vortex Can be formed. Accordingly, the fuel injected from the fuel injection pipe 140 may be rapidly mixed with the air supplied through the air supply passage 161. The diffuser 130 structure of FIG. 4B improves the combustibility of fuel by rapidly mixing fuel and air using vortex.

According to the above process, the fuel and air are rapidly mixed and combusted to form a long-necked flame, the combustion gas S3 is introduced into the long-necked region S1, and the combustion gas S3 is the first gas inlet. By recycling (P1, P2) through the 151 and the second gas inlet 112, the temperature of the combustion gas is lowered and supplied to the region S2 in the excess fuel state to control the thermal and prompt knox (FIG. 5). Reference).

The fuel spud 150 branches from the fuel supply pipe 120 and extends outwardly from the middle portion 112 of the tube 110 and the first spud pipe 152 and the first spud pipe 152. And a second spud pipe 153 which is disposed at intervals to form a first gas inlet 151 and is inserted and inserted through the inside of the tube 110 in the diameter expansion part 116 to form a split flame. Include. An end portion of the first spud tube 152 is provided with an injection connection 154 having a reduced diameter to inject fuel toward the second spud tube 153. In the second spud pipe 153, an end portion of the first gas inlet 151 side is formed with a diameter extension part 153a having a diameter extended toward the first spud pipe 152.

In the first embodiment of the present invention by applying a gas staging method through the first gas inlet 151 and the second gas inlet 112 to lower the temperature of the main flame generated in the combustion head 5, the main flame Thermal knox can be controlled by lowering the temperature of the over split flame, i.e. the temperature of the entire "flame group." The following describes the contents of lowering the temperature of the flame group by incorporating the gas staging method into the IFGR.

3 is a functional state diagram showing the flow of air, fuel gas and combustion gas in the hybrid low-nox burner according to the first embodiment of the present invention, Figure 5 is a hybrid low-nox burner according to the first embodiment of the present invention As a flow conceptual diagram for, a longitudinal flow conceptual diagram at a portion where a fuel spud is located in the diffuser is shown.

As shown in FIG. 3, the air flow A1 is formed through the central air injection pipe 121 to the center of the combustion chamber FR, and the fuel gas flow B1 is formed through the fuel supply pipe 120. While the fuel injection pipe 140 is injected to form a main flame, the fuel gas flow (B2) is formed auxiliary through the fuel spud 150 branched from the fuel supply pipe 120, the fuel is injected to form a split flame Form. At this time, the air flow (C1) through the tube 110 in accordance with the operation of the blower 115 is a combustion gas flow (P2) through which the combustion gas of the combustion chamber (FR) through the second gas inlet 112 ( 110 is introduced into the air and gas flow (C1 + P2) to generate a main flame, the air flow B2 through the first spud pipe 152 of the fuel spud 150 is the first gas inlet The fuel gas flow B2 + P1 is introduced into the second spud pipe 153 of the fuel spud 150 into the combustion gas flow P1 through which the combustion gas of the combustion chamber FR is circulated through the 151. To create a split flame.

The main flame formed through the diffuser 130 and the split flame generated by the fuel spud 150 may form one "flame group." The flame group formed by the diffuser 130 and the fuel spud 150 increases the surface area of the flame inside the combustion chamber FR, thereby lowering the temperature of the flame group by promoting the absorption of radiant heat in the heat transfer surface of the combustion chamber FR. have. In addition, the pressure around the split flame may be lowered by the fuel injected at high speed in the fuel spud 150. Accordingly, the combustion gas S3 primary combusted in the combustion chamber FR is attracted around the diffuser 130 and the fuel spud 150 having a low pressure, which causes the magnetization of the combustion gas S3 inside the combustion chamber FR. Recycling can be induced. When the combustion gas S3 is self-recirculated in the combustion chamber FR toward the fuel spud 150, the fuel spud 150 injects a portion of the combustion gas S3 into the fuel spud 150 to supply fuel. The calorific value of the fuel injected from the spud 150 may be lowered. This can be expected to lower the temperature of the entire flame group.

The fuel spud 150 is divided into a first spud tube 152 and a second spud tube 153, and the fuel is injected from the first spud tube 152 to the second spud 153. The injection pressure at the time lowers the pressure around the first gas inlet 151, and the combustion gas S3 is attracted and introduced to the first gas inlet 151 having a low pressure. That is, when high-pressure fuel is injected from the fuel injection hole of the second spud pipe, the vicinity of the fuel injection hole, for example, the first gas inlet 151 or the surrounding area may have a lower pressure than the injection pressure of the fuel injection hole. The combustion gas S3 is moved toward the first gas inlet 151 in the combustion chamber FR by the pressure difference, and the combustion gas S3 is self-recirculated inside the combustion chamber FR according to the movement of the combustion gas S3. Self-Recirculation can be achieved.

As the combustion gas S3 is attracted to the first gas inlet 151, the fuel injected at the fuel inlet of the second spud pipe 153 becomes a mixture of "fuel + combustion gas S3", instead of air As the combustion gas flows into the second spud pipe 153, the combustibility of the fuel is lower than that of the contact between air and the fuel, and this has the effect of lowering the temperature of the split flame generated in the fuel spud 150. When the temperature of the split flame is lowered, the temperature of the flame group injected from the diffuser 130 and the fuel spud 150 is lowered, which may reduce the thermal knox generated in the flame group.

In addition, the fuel and air injected through the diffuser 130 increases the surface area of the flame inside the combustion chamber FR by the combustion gas introduced through the second gas inlet 112, thereby increasing the surface area of the flame on the heat transfer surface of the combustion chamber FR. By facilitating absorption of radiant heat, the temperature of the flame group can be lowered. That is, after the combustion gas S3 primary combustion in the combustion chamber FR is drawn around the low pressure diffuser 130 and the fuel spud 150, the inside of the tube 110 through the second gas inlet 112. It may be introduced into the to induce a magnetic recycle of the combustion gas (S3). When the combustion gas S3 is self-recirculated in the combustion chamber FR toward the fuel spud 150, a portion of the combustion gas S3 flows into the tube 110 through the second gas inlet 112 and the amount of air is increased. By relatively lowering the effect of lowering the temperature of the entire flame group can be expected.

When the air supplied from the blower 115 flows to the combustion gas guide portion 113 of the tube 110, the pressure around the second gas inlet 112 decreases due to the flow air pressure, and the combustion gas S3 has a low pressure. Induced and introduced into the second gas inlet 112, the combustion gas (S3) to increase the self-recirculation force in the combustion chamber (FR) in accordance with the movement of the combustion gas (S3).

As the combustion gas S3 is attracted to the second gas inlet 112, the air in the tube 110 becomes a mixture of "air + combustion gas S3", and the amount of air decreases, which lowers the combustibility of the fuel. There is an effect of lowering the temperature of the main flame generated in the fuel spud 150. When the temperature of the main flame is lowered, the temperature of the flame group injected from the diffuser 130 and the fuel spud 150 is lowered, which may further reduce the thermal knox generated in the flame group.

FIG. 6 is a side cross-sectional view illustrating a state in which a hybrid low knox burner 200 according to a second embodiment of the present invention is installed in a combustion chamber, and FIG. 7 is a perspective view of the end portion of the tube cut in FIG. 6, and FIG. 8. Is a flow diagram for a hybrid low knox burner according to a second embodiment of the present invention.

In the hybrid low knox burner 200 of the second embodiment, the fuel spud 250 is branched from the fuel supply pipe 220 and the first spud pipe 252 extending out of the tube 210 and the first A second spud which forms the first gas inlet 251 which is spaced apart from the spud tube 252 to form a recirculated combustion gas stream P1 and is arranged outside the tube 210 to form a split flame Tube 253.

At the first gas inlet 251, a second gas inlet 212 forming a combustion gas flow P2 that is recirculated for inlet of the combustion gas mixed with the air inside the tube 210 is located at the rear of the combustion chamber outside in the outer direction of the tube. Is formed.

The remaining configurations, operations and effects of the tube 210, the blower 215, the fuel supply pipe 220, the central air injection pipe 221, the diffuser 230, the fuel injection pipe 240 of the second embodiment, etc. Since it is similar or identical to the one embodiment, a detailed description thereof will be omitted.

On the other hand, the embodiments of the present invention disclosed in the specification and drawings are merely presented specific examples to easily explain the technical contents of the present invention and help the understanding of the present invention, and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

[Description of the code]

100, 200: Combination Low Knox Burner

110 tube 111 side diameter portion

112: second gas inlet 113: combustion gas guide

120: fuel supply pipe 121: central air injection pipe

140: fuel injection pipe 141: fuel nozzle

150: fuel spud 151: first gas inlet

152: first spud pipe 153: second spud pipe

161; Air supply passage

FR: Combustion chamber HL: Burner mounting hole

MP: mounting plate

Claims

Combination low-nox burner installed in the burner mounting hole of the combustion chamber,

A tube inserted into the burner mounting hole, the tip of which is exposed to the combustion chamber, and guides air to the combustion chamber;

At least one end of the tube, having a pipe shape for forming a split flame by injecting fuel into the combustion chamber, and a fuel spud having a first gas inlet for inlet of combustion gas in an outer peripheral region; ,

Combination low-nox burner, characterized in that the second gas inlet for the combustion gas inlet to be mixed with the air in the tube in the outer side of the combustion chamber in the rear in the first gas inlet is formed on the outer periphery of the tube.
The method according to claim 1,

Combination low-nox burner, characterized in that the combustion gas guide is formed obliquely in the flow direction of the air in the second gas inlet.
The method according to claim 1,

The fuel spud

A first spud tube branched from a fuel supply tube and extending out of the tube,

A composite low knox, characterized in that it comprises a second spud tube disposed to be spaced apart from the first spud tube to form the first gas inlet and inserted into the tube to form a split flame. burner.
The method according to claim 1,

The fuel spud

A first spud tube branched from a fuel supply tube and extending out of the tube,

And a second spud tube disposed to be spaced apart from the first spud tube to form the first gas inlet and arranged outside the tube to form a split flame.
The method according to claim 3 or 4,

Combination low knox burner, characterized in that the end of the first spud tube is provided with a reduced diameter injection connection for injecting fuel toward the second spur tube.
The method according to claim 3 or 4,

The first gas inlet side end portion of the second spud tube is a composite low-nox burner, characterized in that the diameter extension portion is formed extending toward the first spud tube.