A low-nitrogen burner for treating formaldehyde tail gas

Abstract

The application discloses a low-nitrogen burner for treating formaldehyde tail gas, relates to the low-nitrogen combustion field, and comprises a swirl flame disc and a waste gas assembly arranged coaxially, and a tail gas pipe and a gas pipe respectively communicated with the swirl flame disc. The swirl flame disc body is in a disc structure, a plurality of through holes are distributed in the circumferential direction of the disc surface, the disc surface is provided with an inner guide vane group and an outer guide vane group arranged in an annular shape in the radial direction, and the two groups of guide vanes are each composed of a plurality of guide vanes arranged at a predetermined angle. The application promotes the gradient distribution of the temperature field in the combustion zone through a two-stage swirl coupling structure, and respectively forms fuel-rich, oxygen-lean and burnout reaction conditions in different regions, so that efficient decomposition of formaldehyde and synergistic inhibition of nitrogen oxides are realized.

Description

Technical Field

[0001] This application relates to the field of low-NOx combustion, and in particular to a low-NOx burner for treating formaldehyde exhaust gas. Background Technology

[0002] In current industrial applications, the harmless treatment of formaldehyde exhaust gas often employs combustion, where formaldehyde and other organic compounds in the exhaust gas are completely oxidized into carbon dioxide and water using a burner. To meet increasingly stringent environmental protection requirements, existing technologies widely incorporate low-NOx (low-NOx) combustion technology into combustion equipment. Common low-NOx burners primarily suppress the formation of NOx during combustion through methods such as flue gas recirculation (FGR), staged air combustion, or staged fuel combustion (reburning). The core principle of these technologies is to reduce the formation of thermal NOx and fuel-based NOx by lowering the peak flame temperature, slowing the mixing process, or creating a locally reducing atmosphere. These general-purpose low-NOx burners have already achieved certain emission reduction effects in the clean combustion of traditional fuels (such as natural gas and oil).

[0003] However, when applied to formaldehyde exhaust gas treatment, existing low-NOx burners exhibit significant technical limitations. First, formaldehyde exhaust gas has a complex and fluctuating composition, often containing hydrogen, carbon monoxide, methanol, and trace amounts of formic acid, whose calorific value and reactivity differ from traditional fuels. General-purpose low-NOx burners rely on stable fuel characteristics and struggle to adapt to the unsteady combustion of formaldehyde exhaust gas, easily leading to decreased combustion efficiency or fluctuations in denitrification effects. Second, formaldehyde molecules (HCHO) themselves contain nitrogen precursors, making them more readily converted into fuel-type NOx during combustion, while conventional staged combustion strategies have limited efficiency in suppressing fuel nitrogen conversion. Furthermore, existing burners are highly sensitive to trace organic impurities (such as formic acid) in the exhaust gas; incomplete oxidation in the low-temperature combustion zone easily produces secondary pollutants such as methyl formate, increasing the burden on end-of-pipe treatment. More importantly, the complex flow field structures designed to achieve low nitrogen effects (such as strong swirl and segmented air distribution) are prone to flameout or deflagration risks when dealing with highly inert components (such as nitrogen-diluted exhaust gas), due to the decrease in flame stability, which directly affects the safety and reliability of equipment operation. Utility Model Content

[0004] The purpose of this application is to overcome at least one deficiency of the prior art and to provide a low-NOx burner for treating formaldehyde exhaust gas.

[0005] To achieve the above objectives, this application discloses a low-NOx burner for treating formaldehyde exhaust gas, which includes a coaxially arranged vortex disk and exhaust gas assembly, as well as an exhaust gas pipe and a combustion gas pipe respectively connected to the vortex disk.

[0006] The main body of the swirling flame disk has a disk-shaped structure, with several through holes distributed around the disk surface. The disk surface is equipped with an inner guide vane group and an outer guide vane group arranged in a ring in the radial direction. Both groups of guide vanes are composed of multiple guide vanes that are inclined at a predetermined angle.

[0007] The exhaust gas assembly includes a cylindrical body and an exhaust gas duct group disposed inside it. A through combustion chamber is formed inside the body, and a vortex disk is fixedly installed in the middle region of the combustion chamber.

[0008] The exhaust gas assembly is further provided with an annular exhaust gas chamber, which is independently configured with an exhaust gas inlet and a pyrolysis gas inlet.

[0009] Multiple exhaust gas ducts are evenly distributed circumferentially, with one end connected to the exhaust gas chamber and the other end passing through the vortex disk and extending to the area where the outer guide vane group is located. The gas pipes are inserted into the central area of ​​the vortex disk in an eccentric layout, with the axis of their outlet end forming a predetermined offset distance from the axis of the vortex disk.

[0010] The exhaust pipe coaxially passes through the center of the vortex disk and extends to the installation position of the inner guide vane group, with its outlet end extending to the area where the outer guide vane group is located.

[0011] Furthermore, the pyrolysis gas inlet is connected to an external pyrolysis reactor for inputting the H2 / CO mixture generated from the catalytic cracking of methane. A spiral guide vane is installed inside the annular waste gas chamber to create a swirling mixed flow between the input circulating waste gas and the pyrolysis gas.

[0012] During operation, formaldehyde exhaust gas is injected into the inner guide vane area through the exhaust pipe, while the fuel gas is eccentrically introduced into the central area of ​​the vortex disk through the fuel gas pipe. Externally sourced pyrolysis gas and recirculated waste gas are input through the pyrolysis gas inlet and waste gas inlet of the waste gas chamber, respectively. After mixing, they are guided through the waste gas duct to the outer guide vane area for ejection.

[0013] The inner guide vane group guides the formaldehyde exhaust gas to form an inner swirling flow field, and the eccentrically introduced fuel gas achieves premixing and diffusion under the action of this flow field; the outer guide vane group drives the waste gas-cracking gas mixed fluid to form an outer swirling flow field, and achieves staged mixing through radial shearing action with the inner airflow.

[0014] Compared with existing technologies, this application promotes the temperature field gradient distribution in the combustion zone through a two-stage swirling coupling structure, and forms fuel-rich, oxygen-deficient and burnout reaction conditions in different regions, thereby achieving efficient formaldehyde decomposition and synergistic suppression of nitrogen oxides.

[0015] The beneficial effects listed above are not exhaustive of all advantages. Other potential beneficial effects and detailed technical implementation methods will be further disclosed in the embodiments or other descriptive sections of this application. Attached Figure Description

[0016] A better understanding of various aspects of this disclosure will be achieved by reading the following detailed description in conjunction with the accompanying drawings. The positions, dimensions, and extents of the structures shown in the drawings, etc., do not always represent actual positions, dimensions, and extents. In the drawings: Figure 1 This is a schematic diagram of the structure of one embodiment disclosed in this application.

[0017] Figure 2 This is a schematic diagram of the internal structure of one embodiment disclosed in this application. Detailed Implementation

[0018] The present disclosure will now be described with reference to the accompanying drawings, which illustrate several embodiments of the present disclosure. However, it should be understood that the present disclosure can be presented in many different ways and is not limited to the embodiments described below; in fact, the embodiments described below are intended to make the disclosure more complete and to fully illustrate the scope of protection of the present disclosure to those skilled in the art. It should also be understood that the embodiments disclosed herein can be combined in various ways to provide further additional embodiments.

[0019] It should be understood that the same reference numerals denote the same elements in all the accompanying drawings. For clarity, the dimensions of certain features may be modified in the drawings.

[0020] It should be understood that the terminology used in this specification is for describing specific embodiments only and is not intended to limit this disclosure. All terms used in this specification (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. For the sake of brevity and / or clarity, techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail; however, where appropriate, such techniques, methods, and apparatus should be considered part of this specification.

[0021] Unless otherwise specified, the singular forms “a,” “the,” and “the” used in this specification include the plural forms. The terms “comprising,” “including,” and “containing” used in this specification indicate the presence of the claimed feature but do not exclude the presence of one or more other features. The term “and / or” used in this specification includes any and all combinations of one or more of the relevant listed items.

[0022] See attached document Figures 1 to 2 In this embodiment, a low-NOx burner for treating formaldehyde exhaust gas has a compact and powerful overall structure. It mainly consists of a coaxially arranged vortex disk 1 and exhaust gas assembly 2, and also includes an exhaust gas pipe 3 and a gas combustion pipe 4 that are respectively connected to the vortex disk. The components work closely together to achieve effective treatment of formaldehyde exhaust gas.

[0023] As one of the core components, the vortex disk 1 has a disk-shaped structure and is made of high-temperature resistant alloy material, possessing good mechanical strength and corrosion resistance. Several through-holes are evenly distributed around the circumference of the disk surface. The shape and size of the through-holes are optimized to ensure smooth gas flow. In the radial direction of the vortex disk 1, annularly arranged inner and outer guide vane groups are cleverly configured. Both groups of guide vanes consist of multiple vanes tilted at predetermined angles. The guide vanes are made of high-strength, high-temperature resistant metal material and are precision-machined. Their tilt angles are rigorously calculated to guide the airflow into a specific vortex field, thereby promoting gas mixing and combustion.

[0024] The exhaust gas assembly 2 is equally crucial. It comprises a cylindrical body and a group of exhaust gas ducts located within it. The body is made of high-quality steel, possessing excellent sealing and pressure resistance. An internal, continuous combustion chamber is formed, with the vortex disk 1 fixedly installed in the central region of this chamber. This layout ensures the stability of the combustion process. The exhaust gas assembly 2 also features an annular exhaust gas chamber, independently configured with exhaust gas inlets and pyrolysis gas inlets. The inlet structure is rationally designed to effectively control the gas inflow velocity and flow rate, ensuring uniform gas mixing. Multiple exhaust gas ducts are evenly distributed circumferentially, one end connecting to the exhaust gas chamber, and the other end penetrating the vortex disk 1 and extending to the area where the outer guide vane group is located. The exhaust gas ducts are made of high-temperature resistant and corrosion-resistant alloy materials, with a smooth interior and low resistance, efficiently guiding the mixed gas to the designated area.

[0025] The gas pipe 4 is inserted into the central area of ​​the swirling flame disk 1 in an eccentric layout, with its outlet axis offset from the axis of the swirling flame disk 1 by a predetermined distance. This design helps to achieve uniform distribution and premixed diffusion of the gas in the swirling flow field. The gas pipe 4 is made of high-quality metal material, possessing good flexibility and pressure resistance, and can withstand pressure changes during gas transportation, ensuring a stable gas supply. The exhaust pipe 3 extends to the installation position of the inner guide vane assembly, with its outlet end face located at the inlet of the annular flow channel formed by the inner guide vane assembly. The exhaust pipe 3 is made of corrosion-resistant and high-temperature-resistant material with a smooth pipe wall, which facilitates the smooth flow of formaldehyde exhaust gas and its efficient cooperation with the inner guide vane assembly.

[0026] Furthermore, the pyrolysis gas inlet is connected to an external pyrolysis reactor to input the H2 / CO mixture produced by the catalytic cracking of methane. This mixture has high reactivity and can effectively promote the decomposition reaction of formaldehyde. Furthermore, the annular exhaust gas chamber is equipped with spiral guide vanes, which cause the input circulating exhaust gas and pyrolysis gas to form a swirling mixed flow within the chamber, enhancing the gas mixing effect and improving combustion efficiency.

[0027] In actual operation, when formaldehyde exhaust gas needs to be treated, it is first injected into the inner guide vane group area through exhaust pipe 3. The inner guide vane group guides the formaldehyde exhaust gas to form an inner swirling flow field. At the same time, fuel gas is eccentrically introduced into the central area of ​​the swirling flame disk 1 through fuel gas pipe 4. Under the action of the inner swirling flow field, the eccentrically introduced fuel gas and formaldehyde exhaust gas achieve premixing and diffusion, forming a local reaction condition rich in fuel and poor in oxygen, which is conducive to the initial decomposition of formaldehyde. Exogenous cracked gas and circulating waste gas are input through the cracked gas inlet and waste gas inlet of the waste gas chamber, respectively. After mixing, they are guided to the outer guide vane group area through the waste gas duct and ejected. The outer guide vane group drives the waste gas-cracking gas mixture to form an outer swirling flow field. Through the radial shearing action with the inner airflow, staged mixing is achieved, thereby forming a temperature gradient distribution in the combustion zone and forming reaction conditions suitable for efficient formaldehyde decomposition and synergistic inhibition of nitrogen oxides in different areas.

[0028] For example, when treating formaldehyde exhaust gas from chemical plants, this low-NOx burner can operate stably, effectively reducing the formaldehyde content in the exhaust gas to a level that meets emission standards. Simultaneously, nitrogen oxide emissions are also significantly reduced. Compared to traditional combustion treatment methods, it has a clear advantage in environmental performance and has achieved excellent treatment results in practical applications, strongly promoting the green development of related industries and providing an effective technical means to solve the problem of formaldehyde exhaust gas treatment. Those skilled in the art should understand that the above embodiments are merely illustrative and not intended to limit the scope of protection of this invention. For some known technologies or prior art that are not disclosed in detail, flexible selection and application can be made according to specific circumstances in practical applications. For example, the fixed installation method of the vortex flame plate and the specific number of exhaust gas ducts can be appropriately adjusted according to actual needs to achieve the best usage effect.

Claims

1. A low NOx burner for treating a formaldehyde tail gas, characterized by, It includes a coaxially arranged vortex disk and exhaust gas assembly, as well as a tail gas pipe and a combustion gas pipe respectively connected to the vortex disk; The main body of the swirling flame disk has a disk-shaped structure, with several through holes distributed around the disk surface. The disk surface is equipped with an inner guide vane group and an outer guide vane group arranged in a ring in the radial direction. Both groups of guide vanes are composed of multiple guide vanes that are inclined at a predetermined angle. The exhaust gas assembly includes a cylindrical body and an exhaust gas duct group disposed inside it. A through combustion chamber is formed inside the body, and a vortex disk is fixedly installed in the middle region of the combustion chamber. The exhaust gas assembly is further provided with an annular exhaust gas chamber, which is independently configured with an exhaust gas inlet and a pyrolysis gas inlet; Multiple exhaust gas ducts are evenly distributed circumferentially, with one end connected to the exhaust gas chamber and the other end passing through the vortex disk and extending to the area where the outer guide vane group is located. The gas pipe is inserted into the central area of ​​the swirling flame disk in an eccentric layout, and its outlet axis forms a predetermined offset distance with the axis of the swirling flame disk. The exhaust pipe coaxially passes through the center of the vortex disk and extends to the installation position of the inner guide vane group, with its outlet end extending to the area where the outer guide vane group is located.

2. A low NOx burner for treating a formaldehyde tail gas as claimed in claim 1, characterized in that The pyrolysis gas inlet is connected to an external pyrolysis reactor.

3. A low NOx burner for treating a formaldehyde tail gas as claimed in claim 1, characterized in that, The annular exhaust gas chamber is equipped with spiral guide vanes, which cause the input circulating exhaust gas and pyrolysis gas to form a swirling mixed flow.

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