A flameless burner with precise air distribution and a flameless combustion method

Abstract

The present invention discloses a flameless burner with precise air distribution and a flameless combustion method. After high-temperature gas flows into a shell, it is evenly dispersed in a gas distribution chamber and then evenly enters each gas pipe; after high-temperature air flows into the shell, it is evenly dispersed in an air distribution chamber and then evenly enters each air passage; the high-temperature gas flowing out of the gas pipe and the high-temperature air flowing out of the air passage are mixed and pre-combusted in a pre-combustion chamber and then sprayed out of the shell to form a flameless combustion area.

Description

Technical Field

[0001] The invention relates to the technical field of burners, and in particular to a flameless burner with precise air distribution and a flameless combustion method. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] The burner is an important equipment of the gas combustion furnace. It ensures the stable ignition of the gas and the complete combustion of the gas. Therefore, to suppress the generation of NOx, we must start with the burner. Low nitrogen oxide burners are roughly divided into stage burners, recirculation burners, thick and thin burners, split flame burners, mixed promotion burners, and low NOx pre-combustion chamber burners. The main way to control NOx is to reasonably reduce the combustion flame temperature and reduce the oxygen content.

[0004] Most of the current gas burners use luminous flame combustion. Compared with flameless combustion, luminous flame combustion has the following disadvantages: 1. The temperature field is unevenly distributed, and the temperature at the flame surface is high; 2. Noise is generated during the combustion of the flame; 3. The furnace heating process is uneven, and the heat transfer efficiency is low; 4. Compared with flameless combustion, the NOx emission of flame combustion is high. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a flameless burner with precise air distribution and a flameless combustion method. The high-temperature fuel and high-temperature air are finely premixed to ensure the ratio of fuel to oxygen, the combustion is flameless, the temperature distribution is uniform, the combustion efficiency is high, and the purpose of improving burnout and reducing NOx emissions is achieved.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] In a first aspect, the present invention provides a flameless burner with precise air distribution, comprising a housing and a gas pipe assembly arranged in parallel, wherein:

[0008] The gas pipe assembly is fixedly arranged inside the shell, the inside of the gas pipe forms a gas passage, and the gas pipes form an air passage.

[0009] The shell forms a high-temperature gas channel and a high-temperature air channel. The gas distribution chamber of the high-temperature gas channel is a chamber with a uniformly expanded diameter and is connected to each gas pipe;

[0010] The air distribution chamber of the high-temperature air channel is a chamber with a uniformly expanded diameter, which is connected to each air passage;

[0011] The end of the gas pipe is located inside the shell and is spaced a set distance from the end of the shell. The side shell is open; the end of the gas pipe and the inner wall of the shell form a pre-combustion chamber.

[0012] In a second aspect, the present invention provides a flameless burner with precise air distribution, comprising a housing and a sleeve assembly arranged in parallel, wherein:

[0013] The sleeve assembly is fixedly arranged inside the shell, and each sleeve includes a gas pipe and an air pipe. The air pipe is sleeved outside the gas pipe to form an air passage with the gas pipe.

[0014] The shell forms a high-temperature gas channel and a high-temperature air channel. The gas distribution chamber of the high-temperature gas channel is a chamber with a uniformly expanded diameter and is connected to each gas pipe;

[0015] The air distribution chamber of the high-temperature air channel is a chamber with a uniformly expanded diameter, which is connected to each air passage;

[0016] The end of the gas pipe is located inside the shell and is spaced a set distance from the end of the shell. The side shell is open; the end of the gas pipe and the inner wall of the shell form a pre-combustion chamber.

[0017] In a third aspect, the present invention provides a flameless combustion method of a flameless burner with precise air distribution, comprising the following steps: after high-temperature gas flows into a shell, it is evenly dispersed in a gas distribution chamber and then evenly enters each gas pipe;

[0018] After the high-temperature air flows into the shell, it is evenly dispersed in the air distribution chamber and then evenly enters each air passage;

[0019] The high-temperature gas flowing out of the gas pipe and the high-temperature air flowing out of the air passage are mixed and pre-combusted in the pre-combustion chamber, and then sprayed out of the shell to form a flameless combustion area.

[0020] The beneficial effects achieved by one or more embodiments of the present invention are as follows:

[0021] The gas flow rate at the gas and air inlets is faster. Since the gas and air close to the shell are subject to greater resistance and have a slower flow rate, while the fluid in the central area is subject to less resistance and has a faster flow rate, the gas flow rate of the fluid at various positions along the cross section of the gas passage with this constant diameter structure is different. Therefore, when fluids with different flow rates are directly introduced into the gas pipe and air passage, it is easy to cause uneven distribution of gas in the gas pipe and air passage.

[0022] The gas distribution chamber and the air distribution chamber are set as chambers with uniformly expanded diameters, where high-temperature gas and high-temperature air with uneven flow rates can be evenly buffered. When entering each passage, the uniformity of fluid distribution in each passage can be effectively improved.

[0023] The end of the gas pipe and the inner wall of the shell form a pre-combustion chamber, and the air flows out of the end of the gas passage and the end of the air passage can be fully mixed in the pre-combustion chamber.

[0024] The above two methods can achieve accurate air distribution to ensure combustion efficiency and improve the burnout rate;

[0025] The gas and air are at high temperature to ensure flameless combustion;

[0026] Flameless combustion has uniform temperature distribution, high combustion efficiency, good combustion stability, improved fuel burnout and reduced NOx emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0028] Figure 1 A front cross-sectional view of a flameless gas burner device with precise air distribution proposed by the present invention;

[0029] Figure 2 for Figure 1 , a cross-sectional view along the AA direction;

[0030] Figure 3 for Figure 1 Schematic diagram of the structure of the air cyclone and the gas cyclone;

[0031] Figure 4 It is a schematic structural diagram of a flameless gas burner device with precise air distribution according to an exemplary embodiment of the present invention;

[0032] Figure 5 It is a schematic structural diagram of a flameless gas burner device with precise air distribution according to another exemplary embodiment of the present invention;

[0033] In the figure: the distances or sizes between parts are exaggerated to show the positions of the parts, and the schematic diagram is for illustration only;

[0034] Among them, 1-high-temperature air inlet pipeline; 2-high-temperature gas inlet pipeline; 3-air distribution chamber; 4-gas distribution chamber; 5-air temperature measuring element; 6-gas temperature measuring element; 7-pre-combustion chamber; 8-shell; 9-refractory layer; 10-thermal insulation layer; 11-ceramic gas pipe; 12-positioning ceramic pipe; 13-positioning ceramic plate; 14-gas cyclone; 15-air cyclone; 16-volute air duct; 17-stepped positioning ceramic plate; 18-volute air duct inlet. DETAILED DESCRIPTION

[0035] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0036] In a first aspect, the present invention provides a flameless burner with precise air distribution, comprising a housing and a gas pipe assembly arranged in parallel, wherein:

[0037] The gas pipe assembly is fixedly arranged inside the shell, the inside of the gas pipe forms a gas passage, and the gas pipes form an air passage.

[0038] The shell forms a high-temperature gas channel and a high-temperature air channel. The gas distribution chamber of the high-temperature gas channel is a chamber with a uniformly expanded diameter and is connected to each gas pipe;

[0039] The air distribution chamber of the high-temperature air channel is a chamber with a uniformly expanded diameter, which is connected to each air passage;

[0040] The end of the gas pipe is located inside the shell and is spaced a set distance from the end of the shell. The side shell is open; the end of the gas pipe and the inner wall of the shell form a pre-combustion chamber.

[0041] In a second aspect, the present invention provides a flameless burner with precise air distribution, comprising a housing and a sleeve assembly arranged in parallel, wherein:

[0042] The sleeve assembly is fixedly arranged inside the shell, and each sleeve includes a gas pipe and an air pipe. The air pipe is sleeved outside the gas pipe to form an air passage with the gas pipe.

[0043] The shell forms a high-temperature gas channel and a high-temperature air channel. The gas distribution chamber of the high-temperature gas channel is a chamber with a uniformly expanded diameter and is connected to each gas pipe;

[0044] The air distribution chamber of the high-temperature air channel is a chamber with a uniformly expanded diameter, which is connected to each air passage;

[0045] The end of the gas pipe is located inside the shell and is spaced a set distance from the end of the shell. The side shell is open; the end of the gas pipe and the inner wall of the shell form a pre-combustion chamber.

[0046] In some embodiments, a swirler is provided at the end of the air pipe and the gas pipe. The swirler is used to swirl the high-temperature gas and high-temperature air flowing out of the air pipe and the gas pipe to effectively promote their mixing, which is beneficial to improving the combustion efficiency.

[0047] In some embodiments, the high-temperature air channel is vertically arranged with the air pipe, and the high-temperature gas channel is vertically arranged with the gas pipe.

[0048] Preferably, a volute air duct is provided at the end of each air pipe, the volute air duct is connected to the air pipe, and its opening faces the air flow direction.

[0049] Further preferably, the volute air duct of each air duct is installed on a stepped positioning ceramic plate, and the volute air duct located downstream is extended outward.

[0050] Since the upstream volute air duct will take in a part of the high-temperature air and will have a certain obstructive effect on the high-temperature air at the flow section, thereby affecting the downstream volute air duct's reception of the high-temperature air, therefore, extending the downstream volute air duct outward in sequence can effectively avoid this adverse effect and evenly receive the high-temperature air.

[0051] In some embodiments, both ends of each gas pipe are installed and fixed by a ceramic positioning plate.

[0052] In some embodiments, the gas pipe is made of alumina ceramic or silicon carbide ceramic.

[0053] In a third aspect, the present invention provides a flameless combustion method of a flameless burner with precise air distribution, comprising the following steps: after high-temperature gas flows into a shell, it is evenly dispersed in a gas distribution chamber and then evenly enters each gas pipe;

[0054] After the high-temperature air flows into the shell, it is evenly dispersed in the air distribution chamber and then evenly enters each air passage;

[0055] The high-temperature gas flowing out of the gas pipe and the high-temperature air flowing out of the air passage are mixed and pre-combusted in the pre-combustion chamber, and then sprayed out of the shell to form a flameless combustion area.

[0056] In some embodiments, the temperature of the high-temperature fuel gas is 1000-1200°C; the temperature of the high-temperature air is 1000-1200°C.

[0057] Preferably, the flow ratio of high temperature fuel gas to high temperature air is 1:0.5-10.

[0058] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0059] In the present invention, terms such as "connected" and "connection" should be understood in a broad sense, indicating that the connection can be fixed, integral or detachable; it can be directly connected or indirectly connected through an intermediate medium. For relevant scientific research or technical personnel in this field, the specific meanings of the above terms in this disclosure can be determined according to specific circumstances, and they cannot be understood as limitations on this disclosure.

[0060] like Figure 1 and Figure 2As shown, a flameless gas burner device with precise air distribution includes a shell 8, a refractory layer, and a thermal insulation layer. The box body includes a high-temperature air inlet pipe 1, a high-temperature gas inlet pipe 2, an air distribution chamber 3, a gas distribution chamber 4, a pre-combustion chamber 7, a ceramic gas pipe 11, a positioning ceramic pipe 12, a positioning ceramic plate 13, a gas cyclone 14, and an air cyclone 15.

[0061] The high-temperature air inlet pipe 1 is welded on the shell 8, and is protected by a fire-resistant layer 9. The heat insulation layer 10 is used for heat insulation. The high-temperature air is usually at 1000-1200°C; the high-temperature gas inlet pipe 2, the high-temperature gas inlet pipe 2 is welded on the box body 8, and is protected by a fire-resistant layer 9. The heat insulation layer 10 is used for heat insulation. The high-temperature gas is usually at 1000-1200°C; the high-temperature air enters the air distribution chamber 3 through the high-temperature air inlet for diffusion; the high-temperature gas enters the gas distribution chamber 4 through the high-temperature gas inlet for diffusion; there is an air temperature measuring element 5 at the high-temperature air inlet to accurately measure the temperature of the high-temperature air; there is a gas temperature measuring element 6 at the high-temperature gas inlet to accurately measure the temperature of the high-temperature gas.

[0062] After being diffused in the air distribution chamber 3, the high-temperature air enters the volute air duct 16, and enters the air pipe through the volute air duct 16. The air cyclone 15 is located at the end of the air pipe. After the high-temperature air flows through the air cyclone 15, it enters the pre-combustion chamber 7 and is fully and accurately mixed with the high-temperature fuel gas for flameless combustion.

[0063] The air cyclone 15 (such as Figure 3 As shown) is installed between the ceramic gas pipe 11 and the positioning ceramic plate 13; after the high-temperature gas is diffused in the gas distribution chamber 4, it passes through several gas cyclones 14 into the pre-combustion chamber 7 and is fully and accurately mixed with the high-temperature air for flameless combustion; the gas cyclone 14 is installed at the outlet of the ceramic gas pipe 11.

[0064] The ceramic gas pipe 11 is fixed between two positioning ceramic plates 13. The ceramic gas pipe can be made of alumina ceramic, silicon carbide ceramic, etc. The inside of the ceramic gas pipe is a passage for high-temperature gas, and the outside of the ceramic gas pipe is a passage for high-temperature air. The ceramic pipe can be water-cooled for temperature control.

[0065] The positioning ceramic tube 12 is used to fix the relative position of the two positioning ceramic plates and ensure the installation positioning size of the ceramic gas pipe 11; the two ends of the positioning ceramic tube have threaded columns for installing nuts to fix the positions of the two positioning ceramic plates, and the nuts are also made of ceramic material.

[0066] The positioning ceramic plate 13 has several stepped holes and six positioning holes. The stepped holes are used for installing the ceramic gas pipe on the positioning ceramic plate; and the six positioning holes are used for installing the positioning ceramic pipe on the positioning ceramic plate.

[0067] The function of the gas cyclone 14 is to make the high-temperature gas achieve a swirling effect after passing through, and accurately burn without flame after being fully mixed with the high-temperature air; the gas cyclone is installed at the outlet of the gas ceramic pipe, and the fixing form can be bonding or threaded connection.

[0068] The function of the air cyclone 15 is to make the high-temperature air achieve a swirling effect after passing through, and to accurately burn without flame after being fully mixed with the high-temperature gas; the air cyclone is installed between the gas ceramic tube and the positioning ceramic plate or in the volute air guide pipe, and the fixing form can be bonding or threaded connection.

[0069] exist Figure 4 In the embodiment, the air pipe is directly connected to the air distribution chamber 3, the end of the air pipe is fixed by a positioning ceramic plate, and the positioning ceramic plate at the end of the ceramic gas pipe and the positioning ceramic plate at the end of the air pipe and the shell form a high-temperature air receiving chamber to prevent the high-temperature air from flowing to other areas. After the high-temperature air enters the air distribution chamber 3, it directly enters the air pipe, and flows through the air cyclone 15 at the end of the air pipe into the pre-combustion chamber 7.

[0070] exist Figure 5 In the process, air enters the air distribution chamber 3, enters the volute air guide pipe 16, and then enters the air duct 17, and passes through the air cyclone 15 at the end of the air duct through the positioning ceramic plate 13 to enter the pre-combustion chamber and the nozzle 7. Figure 5 The positioning ceramic plate is stepped and is used to install and fix the volute air duct 16 and intercept the high-temperature air to ensure that the high-temperature air can evenly enter the volute air duct 16.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A flameless burner with precise air distribution. Features: It comprises a shell and a sleeve assembly arranged in parallel, wherein the sleeve assembly is fixedly arranged inside the shell, each sleeve comprises a gas pipe and an air pipe, and the air pipe is sleeved outside the gas pipe to form an air passage with the gas pipe; The shell forms a high-temperature gas channel and a high-temperature air channel. The gas distribution chamber of the high-temperature gas channel is a chamber with a uniformly expanded diameter and is connected to each gas pipe; The air distribution chamber of the high-temperature air channel is a chamber with a uniformly expanded diameter, which is connected to each air passage; The end of the gas pipe is located inside the shell and is spaced a set distance from the end of the shell, and the shell is open; the end of the gas pipe and the inner wall of the shell form a pre-combustion chamber; A volute air duct is provided at the end of each air pipe, the volute air duct is connected to the air pipe, and its opening faces the air flow direction; The volute air guide pipe of each air pipe is installed on the stepped positioning ceramic plate, and the volute air guide pipe located downstream is extended outward.

2. The flameless burner with precise air distribution according to claim 1, Features: Swirls are provided at the ends of the air pipe and the gas pipe.

3. The flameless burner with precise air distribution according to claim 1, Features: The high-temperature air passage is vertically arranged with the air pipe, and the high-temperature gas passage is vertically arranged with the gas pipe.

4. The flameless burner with precise air distribution according to claim 1, Features: Both ends of each gas pipe are installed and fixed by ceramic positioning plates.

5. The flameless burner with precise air distribution according to claim 1, Features: The gas pipe is made of alumina ceramic or silicon carbide ceramic.

6. A flameless combustion method using the flameless burner with precise air distribution as claimed in any one of claims 1 to 5, Features: The method comprises the following steps: after the high-temperature gas flows into the shell, it is evenly dispersed in the gas distribution chamber and then evenly enters each gas pipe; After the high-temperature air flows into the shell, it is evenly dispersed in the air distribution chamber and then evenly enters each air passage; The high-temperature gas flowing out of the gas pipe and the high-temperature air flowing out of the air passage are mixed and pre-combusted in the pre-combustion chamber, and then sprayed out of the shell to form a flameless combustion area.

7. The flameless combustion method of the flameless burner with precise air distribution according to claim 6, Features: The temperature of high temperature gas is 1000-1200 °C; the temperature of high temperature air is 1000-1200 °C; The flow ratio of high temperature fuel gas to high temperature air is 1:0.5-10.

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