Multi-nozzle direct injection type natural gas burner

Abstract

The utility model discloses a multi-nozzle direct injection type natural gas burner, and particularly relates to the field of low-nitrogen burners capable of efficiently reducing nitrogen oxide emission. The system comprises a first-stage fuel nozzle, a first-stage air nozzle, a second-stage fuel nozzle, a second-stage air nozzle, a partition plate and a rotational flow channel. According to the low-nitrogen combustor, the purpose of efficiently reducing emission of nitric oxide is achieved through coupling of the staged combustion technology and the rotational flow combustion technology, the mixing degree of air and fuel gas is enhanced through rotational flow of the air nozzle, flames are made to be stable, staged combustion is achieved due to the existence of the partition plate, multi-stage flames are formed within the range meeting the air-fuel ratio, and the combustion efficiency is improved. And the local combustion temperature is reduced, so that pollution emission is reduced.

Description

Technical Field

[0001] This utility model relates to the field of burners, and particularly to the field of staged low-NOx burners for natural gas that can efficiently reduce NOx emissions. Background Technology

[0002] With increasing environmental awareness and the continuous improvement of relevant laws and regulations, the requirements for low emissions from combustion equipment in industrial, commercial, and residential sectors are becoming increasingly stringent. Natural gas, as a clean energy source, produces combustion products containing almost no sulfur dioxide or particulate matter; its main pollutant emission is nitrogen oxides (NOx). Besides harming human health, NOx is a major contributor to acid rain, photochemical smog, and ozone depletion, and a significant culprit in the generation of PM2.5 (fine particulate matter).

[0003] Low-NOx combustion technology can effectively reduce nitrogen oxide emissions and is widely used in various fields. With the continuous expansion of burner applications and the increasing variety of burners, coupled with the need to meet the demands of low carbon emissions, energy conservation, and emission reduction, the industry has entered a phase of rapid development. In recent years, almost all newly commissioned large-capacity boiler units in my country have adopted low-NOx burners, but the results have not been ideal, and NOx emissions remain high.

[0004] This utility model discloses a multi-nozzle direct-injection natural gas burner. This low-NOx burner combines staged combustion technology and swirling combustion technology, and adopts a special non-premixed combustion design. The first-stage combustion device injects fuel and air through a central hole and multiple channels respectively, and the second-stage combustion device injects fuel and air through four vertical pipes and multiple channels respectively. This staged structure can form a multi-stage flame and reduce the local combustion temperature. In addition, the air channels are oriented at a certain angle to generate vortices to stabilize the flame. The multiple channels increase the mixing rate of fuel and air, thereby reducing the emission of nitrogen oxides. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems by providing a natural gas staged burner that can reduce nitrogen oxide emissions. This burner enables staged swirl combustion of fuel and air, coupling two low-NOx technologies together for more efficient and green combustion.

[0006] To achieve the above objectives, the present invention provides the following technical solution: including a primary fuel nozzle, a primary air nozzle, a secondary fuel nozzle, a secondary air nozzle, a partition plate, and a swirl channel, characterized in that the natural gas low-NOx burner has an overall cylindrical shape, with a direct-injection primary fuel nozzle at the center, which is connected to the bottom of the funnel-shaped swirl channel, and a primary air nozzle, a secondary fuel nozzle, and a secondary air nozzle existing between the outer cylinder and the swirl channel.

[0007] Preferably, the diameter of the primary fuel nozzle pipe is twice the diameter of the other pipes. Both the primary and secondary air nozzles have eight air channels, and the secondary fuel nozzle has four fuel channels.

[0008] Preferably, the secondary fuel nozzle is a direct injection nozzle connected to the side of the swirl channel.

[0009] Preferably, the pipes of the primary air nozzle and the secondary air nozzle are arranged at an angle, and the resulting swirl angle is 45°.

[0010] Preferably, the partition plate separates the primary combustion device and the secondary combustion device to form a staged device. The primary combustion device includes a primary fuel nozzle and a primary air nozzle, and the secondary combustion device includes a secondary fuel nozzle and a secondary air nozzle.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows: This multi-nozzle direct injection natural gas burner achieves the goal of efficiently reducing nitrogen oxide emissions by coupling staged combustion technology and swirl combustion technology. The air channel has a fixed angle, and the swirl of the air nozzles enhances the mixing degree of air and gas, making the flame stable. This avoids the installation of swirl vanes, saving installation steps and material costs. Furthermore, due to the presence of the partition plate, staged combustion can be directly achieved in the swirl channel, forming a multi-stage flame within the range of satisfying the air-fuel ratio, reducing the local combustion temperature, and thus reducing thermal nitrogen oxide pollution emissions. Attached Figure Description

[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0013] Figure 1 This is a schematic diagram of the internal structure of a multi-nozzle direct-injection natural gas burner according to the present invention;

[0014] Figure 2 This is a top view of a multi-nozzle direct-injection natural gas burner according to this utility model;

[0015] Figure 3 This is a schematic diagram of the pipeline inlet distribution of a multi-nozzle direct-injection natural gas burner according to this utility model.

[0016] In the diagram: 1 - Primary fuel nozzle, 2 - Primary air nozzle, 3 - Secondary fuel nozzle, 4 - Secondary air nozzle, 5 - Divider plate, 6 - Swirl channel Detailed Implementation

[0017] This section will describe in detail the specific embodiments of the present utility model. The more ideal embodiments of the present utility model are shown in the accompanying drawings. The purpose of the drawings is mainly to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and implementation method of the present utility model, but they should not be construed as limiting the scope of protection of the present utility model.

[0018] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0019] In this utility model, unless otherwise explicitly specified and limited, the terms "installation", "connection", "linking", "fixing", etc., should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in combination with the specific content of the technical solution.

[0020] Please see Figure 1 —3, This utility model provides a technical solution: a multi-nozzle direct-injection natural gas burner, including a primary fuel nozzle (1), a primary air nozzle (2), a secondary fuel nozzle (3), a secondary air nozzle (4), a partition plate (5), and a swirl channel (6), characterized in that the overall shape of the natural gas low-NOx burner is a columnar body, with a direct-injection primary fuel nozzle (1) at the center, which is connected to the bottom of the funnel-shaped swirl channel (6), and a primary air nozzle (2), a secondary fuel nozzle (3), and a secondary air nozzle (4) are located between the outer cylinder and the swirl channel (6), wherein the diameter of the primary fuel nozzle (1) pipe is twice the diameter of the other pipes; the secondary fuel nozzle (3) is a direct-injection nozzle, which is connected to the side of the swirl channel (6). The primary air nozzle (2) and the secondary air nozzle (4) each have 8 air channels, and the secondary fuel nozzle (3) has 4 fuel channels. The pipes of the primary air nozzle (2) and the secondary air nozzle (4) are arranged at an angle, and the resulting swirl angle is 45°. The partition plate (5) separates the primary combustion device and the secondary combustion device. The primary combustion device includes the primary fuel nozzle (1) and the primary air nozzle (2), and the secondary combustion device includes the secondary fuel nozzle (3) and the secondary air nozzle (4).

[0021] Specifically, by installing this multi-nozzle direct-injection natural gas burner, when air is injected through the channel connected to the primary air nozzle (2), the injected air has a certain speed due to the directional angle of the channel. Therefore, an air vortex is formed in the funnel-shaped vortex channel (6), which mixes with the natural gas injected from the direct-injection primary fuel nozzle (1) at the center. The air vortex can not only enhance the mixing degree of air and gas, prolong the combustion time of gas and air, and increase the combustion efficiency, but also stabilize the flame and the combustion process. Similarly, the vortex air injected from the secondary air nozzle (4) mixes with the gas injected from the secondary fuel nozzle (3) in the vortex channel (6). The partition plate (5) separates it into a primary combustion device and a secondary combustion device. The secondary vortex air fully contacts and surrounds the primary mixture in the center. After passing through the point, a vortex flame is formed. The addition of the secondary direct-flow gas can disperse the high-temperature flame area in the center, thereby reducing the generation of thermal nitrogen oxides. Because the central mixture has a faster flow velocity and a larger pressure change range, it is easy to form a low-pressure zone. The secondary swirling velocity is slower than the primary swirling velocity and it envelops the primary swirling velocity. Therefore, a high-temperature flue gas recirculation zone is easily formed in the central position. The high temperature of the flue gas can provide energy for ignition and improve the stability of the flame. In addition, the air channels connected to the 8 primary air nozzles (2) and the air channels connected to the 8 secondary air nozzles (4) are all arranged at a 45° angle, so that the ejected air directly forms a swirling flow, reducing the trouble of installing the stationary blade grid and saving material costs.

[0022] The embodiments of this utility model have been described in detail above with reference to the accompanying drawings. However, those skilled in the art should understand that this utility model is not limited to the above embodiments. The examples and descriptions in the specification are merely illustrative of the principles of this utility model. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this utility model. The scope of protection of this utility model is defined by the appended claims.

Claims

1. A multi-nozzle direct-injection natural gas burner, comprising a primary fuel nozzle (1), a primary air nozzle (2), a secondary fuel nozzle (3), a secondary air nozzle (4), a partition plate (5), and a swirl channel (6), characterized in that... The multi-nozzle direct-injection natural gas burner has a direct-injection primary fuel nozzle (1) at its center, which is connected to the bottom of the funnel-shaped swirl channel (6). Between the outer cylinder and the swirl channel (6) are a primary air nozzle (2), a secondary fuel nozzle (3), and a secondary air nozzle (4).

2. The multi-nozzle direct-injection natural gas burner according to claim 1, characterized in that: The diameter of the primary fuel nozzle (1) pipe is twice that of the other pipes.

3. The multi-nozzle direct-injection natural gas burner according to claim 1, characterized in that: The secondary fuel nozzle (3) is a direct injection nozzle and is connected to the side of the swirl channel (6).

4. A multi-nozzle direct-injection natural gas burner according to claim 1, characterized in that: The primary air nozzle (2) and the secondary air nozzle (4) each have 8 air channels, and the secondary fuel nozzle (3) has 4 fuel channels.

5. A multi-nozzle direct-injection natural gas burner according to claim 1, characterized in that: The pipes of the primary air nozzle (2) and the secondary air nozzle (4) are arranged at an angle, and the resulting swirl angle is 45°.

6. A multi-nozzle direct-injection natural gas burner according to claim 4, characterized in that: The partition plate (5) separates the primary combustion device and the secondary combustion device.

7. A multi-nozzle direct-injection natural gas burner according to claim 5, characterized in that: The primary combustion device includes a primary fuel nozzle (1) and a primary air nozzle (2), and the secondary combustion device includes a secondary fuel nozzle (3) and a secondary air nozzle (4).

8. A multi-nozzle direct-injection natural gas burner according to claim 1, characterized in that: The materials required for burner manufacturing are heat-resistant.

Images