Combustion radiant tube
The radiant tube with multi-stage combustion design solves the problems of low combustion efficiency and high NOx emission of existing radiant tubes, realizes full combustion of fuel and energy saving and consumption reduction, reduces NOx emission and improves thermal efficiency.
Patent Information
- Application Number
- CN202422067886.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-26
- Publication Date
- 2025-09-23
- Estimated Expiration
- 2034-08-26
AI Technical Summary
Existing radiant tubes have low combustion efficiency, high NOx emissions, increased fuel consumption, and high flue gas outlet temperatures, which have increased pressure on the steel industry to save energy and reduce emissions.
It adopts a multi-stage combustion method, introduces fuel and combustion-supporting gas through the fuel inlet and combustion-supporting gas inlet, and utilizes the structural design of the inner sleeve and outer sleeve to achieve primary combustion and multi-stage diffusion combustion, thereby improving combustion efficiency and reducing NOx emissions.
It improves the full combustion rate of fuel, reduces NOx emissions, achieves the goal of energy saving and consumption reduction, and improves thermal efficiency and flue gas recovery efficiency.
Smart Images
Figure CN223375799U_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the technical field of radiant tube equipment, and in particular relates to a combustion radiant tube. Background Art
[0002] As the steel industry continues to intensify its efforts to save energy and reduce emissions, nitrogen oxide (NOx) emission standards are rising annually. Radiant tubes heat the workpiece within the furnace through radiation heat transfer from the high-temperature flue gas generated by internal burners. They are widely used in heating furnaces as the primary heating element. According to incomplete statistics, there are currently over 15,000 radiant tubes in use in my country's steel industry, and demand is increasing annually.
[0003] The overall combustion efficiency of existing radiant tubes is low. In actual applications, NOx emissions are generally high, and the flue gas outlet temperature is high, resulting in incomplete combustion and increased fuel consumption. At the same time, the steel industry is facing great pressure to save energy and reduce emissions. Therefore, the design and research of radiant tubes plays an extremely important role. Utility Model Content
[0004] The present application aims to solve the technical problem of incomplete combustion of radiant tubes to at least a certain extent. To this end, the present application provides a combustion radiant tube that can improve the overall combustion efficiency through multi-stage combustion, make the fuel burn more fully, and achieve the purpose of energy saving and consumption reduction.
[0005] The embodiment of the present application provides a combustion radiation tube, which includes:
[0006] The pipe body has a cavity inside and is provided with a fuel inlet, a combustion-supporting gas inlet and a smoke outlet connected to the cavity;
[0007] An inner sleeve is located in the cavity, one end of the inner sleeve is connected to the tube body and is provided with a first combustion-supporting gas port, the other end of the inner sleeve is provided with a combustion outlet and a diffusion hole, and a mixing combustion chamber is provided inside the inner sleeve, the mixing combustion chamber is used to mix fuel and combustion-supporting gas and provide a combustion space, one end of the mixing combustion chamber is connected to the combustion outlet, and the other end of the mixing combustion chamber is respectively connected to the first combustion-supporting gas port and the fuel inlet;
[0008] The outer sleeve is located in the cavity, and the outer sleeve is sleeved on the outside of the inner sleeve. There is an air flow channel between the outer sleeve and the inner sleeve. One end of the air flow channel is connected to the combustion-supporting gas inlet, and the other end of the air flow channel is connected to the diffusion hole. A plurality of combustion-supporting gas ports are provided at the end of the outer sleeve near the combustion outlet.
[0009] In an optional embodiment, a second combustion-supporting gas port and a third combustion-supporting gas port are provided at the end of the outer sleeve, the second combustion-supporting gas port is adjacent to the combustion outlet, and the third combustion-supporting gas port is spaced apart from the second combustion-supporting gas port.
[0010] In an optional embodiment, the distance between the diffusion hole and the second combustion-supporting gas port is greater than the distance between the third combustion-supporting gas port and the second combustion-supporting gas port, so that the fuel entering the air flow channel through the diffusion hole can flow to the second combustion-supporting gas port and the third combustion-supporting gas port along with the combustion-supporting gas in the air flow channel.
[0011] In an optional embodiment, a fuel pipe is further included, which is located in the cavity, one end of the fuel pipe is connected to the fuel inlet, and the other end of the fuel pipe is used to provide fuel to the mixing combustion chamber.
[0012] In an optional embodiment, a burner is further included, which is connected to the inner sleeve, and a mixing combustion chamber is formed between the burner and the combustion outlet. There is a gap between the burner and the fuel pipe, so that the combustion-supporting gas passing through the first combustion-supporting gas port can enter the mixing combustion chamber together with the fuel at the gap.
[0013] In an optional embodiment, a conduit is further included, which is arranged in the cavity. The conduit is located outside the end of the outer sleeve. The conduit is arranged opposite to the combustion outlet and is spaced apart, so that the airflow discharged from the combustion outlet and the combustion-supporting gas port enters the conduit.
[0014] In an optional embodiment, a reflux channel is provided between the conduit and the tube body, so that the post-combustion airflow passes through the conduit and then flows in the reverse direction through the reflux channel.
[0015] In an optional embodiment, a refractory material section is further included, which is arranged on the tube wall of the tube body. The refractory material section is located at the end of the tube body near the combustion-supporting gas inlet. The refractory material section is provided with a flue gas outlet, and a flue gas channel is formed between the outer sleeve and the tube body. The flue gas outlet is connected to the reflux channel through the flue gas channel.
[0016] In an optional embodiment, it also includes multiple heat conductive parts, which are used for heat exchange between the flue gas in the flue gas channel and the combustion-supporting gas in the air flow channel. The multiple heat conductive parts are arranged around the tube wall of the outer sleeve and are arranged along both ends of the flue gas channel.
[0017] In an optional embodiment, the pipe further includes a fuel flange connected to the pipe body, and the fuel flange has a fuel channel communicating with the fuel inlet.
[0018] It can be seen from the above technical solution that the beneficial effects of this application are:
[0019] The present application introduces fuel and combustion-supporting gas into its internal cavity through a fuel inlet and a combustion-supporting gas inlet, wherein the combustion-supporting gas enters through the first combustion-supporting gas port and enters a mixing combustion chamber together with the fuel and burns in the mixing combustion chamber, which is a first-stage combustion, and the burned gas is discharged from the combustion outlet to the outside of the outer sleeve and inside the tube body, while the other part of the combustion-supporting gas that enters flows through the air flow channel to the end of the outer sleeve, wherein the residual fuel in the mixing combustion chamber enters the air flow channel through the diffusion hole, mixes with the combustion-supporting gas, and is then discharged from multiple combustion-supporting gas ports and burns after being discharged, forming a second-stage, a third-stage and other multi-stage combustion outside the multiple combustion-supporting gas ports. In this way, the overall combustion efficiency can be improved through multi-stage combustion, the fuel can be burned more fully, and the purpose of energy saving and consumption reduction can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, a brief introduction will be given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other embodiments and drawings can be obtained based on these drawings without any creative work.
[0021] Figure 1 A schematic diagram of an embodiment of a combustion radiation tube of the present invention is shown;
[0022] Figure 2 Shows an embodiment of the combustion radiation tube of the utility model Figure 1 Middle AA cross-sectional view;
[0023] Figure 3 A schematic diagram of an embodiment of a combustion radiation tube of the present invention is shown;
[0024] Figure markings: 100, combustion radiation tube; 110, tube body; 111, cavity; 112, fuel inlet; 113, combustion-supporting gas inlet; 114, flue gas outlet; 120, fuel pipe; 130, burner; 140, inner sleeve; 141, mixing combustion chamber; 142, first combustion-supporting gas port; 143, diffusion hole; 144, combustion outlet; 150, outer sleeve; 151, second combustion-supporting gas port; 152, third combustion-supporting gas port; 153, air flow channel; 154, flue gas channel; 160, heat conductor; 170, conduit; 171, reflux channel; 180, refractory material section; 190, fuel flange. DETAILED DESCRIPTION
[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0026] It should be noted that all directional indications in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.
[0027] In this utility model, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. For those skilled in the art, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.
[0028] In addition, in this utility model, the descriptions of "first" and "second" are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features specified as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this utility model.
[0029] The present application is described below with reference to specific embodiments and with reference to the accompanying drawings:
[0030] Please refer to Figure 1In a first embodiment of the present application, a combustion radiation tube 100 is provided, which includes a tube body 110, an inner sleeve 140 and an outer sleeve 150. The tube body 110, the inner sleeve 140 and the outer sleeve 150 are respectively tubular, the outer diameter and the inner diameter of the tube body 110 are respectively larger than those of the outer sleeve 150, and the outer diameter and the inner diameter of the outer sleeve 150 are respectively larger than those of the inner sleeve 140. The tube body 110 has a cavity 111 inside, and the tube body 110 is provided with a fuel inlet 112, a combustion-supporting gas inlet 113 and a flue gas outlet connected to the cavity 111. The fuel inlet 112 is located at one end of the pipe body 110, and the combustion-supporting gas inlet 113 and the smoke outlet 114 are close to the end. The combustion-supporting gas inlet 113 and the smoke outlet 114 can also be located at other positions of the pipe body 110, as long as the cavity 111 is connected. The inner sleeve 140 is located in the cavity 111, and one end of the inner sleeve 140 is connected to the pipe body 110 and fixed by welding. The inner sleeve 140 is provided with a plurality of holes extending through the inner and outer sides thereof. The first combustion-supporting gas port 142 is located at one end of the inner sleeve 140 near the fuel inlet 112. The other end of the inner sleeve 140 is provided with a combustion outlet 144 and a diffusion hole 143. The interior of the inner sleeve 140 is provided with a mixed combustion chamber 141. The combustion outlet 144 is located at the center of the end of the inner sleeve 140. The diffusion hole 143 is located at the outer side of the end of the inner sleeve 140. The gas in the mixed combustion chamber 141 can be discharged from the inner sleeve 140 to the outside of the inner sleeve 140 through the diffusion hole 143. Between the outer sleeve 150, the mixing combustion chamber 141 is used to mix fuel and combustion-supporting gas and provide a combustion space. The combustion-supporting gas enters through the combustion-supporting gas inlet 113, and the other end of the mixing combustion chamber 141 is connected to the first combustion-supporting gas port 142 and the fuel inlet 112 respectively. The fuel first passes through the first combustion-supporting gas port 142 and then enters the mixing combustion chamber 141 together with the fuel entering from the fuel inlet 112. One end of the mixing combustion chamber 141 is connected to the combustion outlet 144, and the combusted gas is ejected outward through the combustion outlet 144.
[0031] The outer sleeve 150 is located in the cavity 111, and the outer sleeve 150 is sleeved on the outside of the inner sleeve 140, and there is a gap between the outer sleeve 150 and the inner sleeve 140, and the gap is an air flow channel 153. One end of the air flow channel 153 is connected to the combustion-supporting gas inlet 113, so that part of the air entering through the combustion-supporting gas inlet 113 can enter the air flow channel 153, and the other end of the air flow channel 153 is connected to the diffusion hole 143. A plurality of combustion-supporting gas ports are provided at the end of the outer sleeve 150 near the combustion outlet 144, and different combustion-supporting gas ports are spaced apart. Through the diffusion hole 143, the fuel that is not completely burned in the mixed combustion chamber 141 enters the air flow channel 153 for diffusion combustion, thereby preventing local high-temperature areas from occurring inside the radiation tube; through the first combustion-supporting gas port 142 and the plurality of combustion-supporting gas ports, a plurality of fluid paths are provided for the mixed fuel, and the gas in the air flow channel 153 can be discharged from the outer sleeve 150 through the plurality of combustion-supporting gas ports, thus forming a multi-stage diffusion combustion mode, and the fuel can be burned in multiple stages.
[0032] The overall combustion efficiency of the radiant tube of the prior art is relatively low, mainly due to incomplete combustion. The fuel not only burns in the air, but also reacts with nitrogen in the air to produce NOx, resulting in generally high NOx emissions. In this way, the fuel utilization rate is not high and the consumption is also increased. The present application introduces fuel and combustion-supporting gas into its internal cavity 111 through the fuel inlet 112 and the combustion-supporting gas inlet 113, wherein the combustion-supporting gas enters through the first combustion-supporting gas port 142 and enters the mixed combustion chamber 141 together with the fuel, and burns in the mixed combustion chamber 141, which is a first-stage combustion. The post-combustion gas is discharged from the combustion outlet 144 to the outside of the outer sleeve and into the tube body 110. At the same time, another part of the combustion-supporting gas that enters flows through the airflow channel 153 to the end of the outer sleeve 150, wherein the residual combustion gas in the mixed combustion chamber 141 The fuel enters the air flow channel 153 through the diffusion hole 143, mixes with the combustion-supporting gas, and is discharged from multiple combustion-supporting gas ports. After discharge, it burns, forming secondary, tertiary and other multi-stage combustion outside the multiple combustion-supporting gas ports. In this way, the overall combustion efficiency can be improved through multi-stage combustion, and the fuel can be burned more fully, thereby achieving the purpose of energy saving and consumption reduction; when air is used as the combustion-supporting gas, since the fuel can be burned more fully, the degree of reaction between the fuel and nitrogen in the air is reduced, thereby significantly reducing the NOx content in the flue gas and improving the flue gas recovery efficiency.
[0033] Please refer to Figure 2In an optional embodiment, the end of the outer sleeve 150 is provided with a second combustion-supporting gas port 151 and a third combustion-supporting gas port 152 that pass through the inner and outer sides. The second combustion-supporting gas port 151 is adjacent to the combustion outlet 144, and the third combustion-supporting gas port 152 is separated from the second combustion-supporting gas port 151. Specifically, the end of the inner sleeve 140 extends outward, the second combustion-supporting gas port 151 is at the outer periphery of the extension section, and the third combustion-supporting gas port 152 is at a distance from the second combustion-supporting gas port 151. The gas in the airflow channel 153 can be discharged from the second combustion-supporting gas port 151 and the third combustion-supporting gas port 152. In an optional embodiment, the distance between the diffusion hole 143 and the second combustion-supporting gas port 151 is greater than the distance between the third combustion-supporting gas port 152 and the second combustion-supporting gas port 151, so that the fuel entering the air flow channel 153 through the diffusion hole 143 can flow to the second combustion-supporting gas port 151 and the third combustion-supporting gas port 152 along with the combustion-supporting gas in the air flow channel 153, and is first discharged from the third combustion-supporting gas port 152 and then discharged from the second combustion-supporting gas port 151, so that the residual fuel can be discharged from the outer sleeve 150 together with the air.
[0034] Please refer to Figure 3 In an optional embodiment, the combustion radiation tube 100 further includes a fuel pipe 120, which is located in the cavity 111. One end of the fuel pipe 120 is connected to the fuel inlet 112, and the other end of the fuel pipe 120 is used to provide fuel to the mixing combustion chamber 141. The fuel pipe 120 is a longer pipe. There is a wider space between the outer wall of the fuel pipe 120 and the inner wall of the inner sleeve 140 to facilitate the circulation of air entering through the first combustion-supporting gas port 142. One end of the fuel pipe 120 is welded and fixed to the inner wall of the end of the tube body 110, and the fuel pipe 120 is connected to the fuel inlet 112, and the other end thereof extends all the way toward the combustion outlet 144. In an optional embodiment, the combustion radiation tube 100 further includes a fuel flange 190, which is connected to the tube body 110 and fixed by bolting, and the fuel flange 190 has a fuel channel connected to the fuel inlet 112, and one end of the fuel channel is connected to the outside, so that the fuel channel is connected to the interior of the fuel pipe 120, and fuel, such as gas, can be introduced into the fuel pipe 120 through the fuel flange 190.
[0035] In an optional embodiment, a burner 130 is further included, which is connected to the inner sleeve 140. The burner 130 is cylindrical and has the ability to diffuse airflow. It is trumpet-shaped. One end of the burner 130 is an airflow inlet. There is a gap between this end and the end of the fuel pipe 120, so that the combustion-supporting gas passing through the first combustion-supporting gas port 142 can enter the mixing combustion chamber 141 together with the fuel at the gap. The other end of the burner 130 is larger in size and is welded to the inner wall of the inner sleeve 140. The mixture of fuel and air is ignited by the burner 130, and a mixing combustion chamber 141 is formed between the burner 130 and the combustion outlet 144. The fuel burns in the mixing combustion chamber 141.
[0036] In an optional embodiment, the combustion radiation tube 100 also includes a conduit 170, which is arranged in the cavity 111. The outer periphery of the conduit 170 can be connected and welded to the inner wall of the tube body 110 with a stiffening plate. The stiffening plate is not shown in the figure and is located at other circumferential positions of other conduits 170. The conduit 170 is located outside the end of the outer sleeve 150. The outer diameter of the conduit 170 is smaller than the inner diameter of the tube body 110, and the inner diameter range of the conduit 170 is larger than the radius of the circle on which the third combustion-supporting gas port 152 is located. The conduit 170 is arranged opposite to the combustion outlet 144 and is spaced apart so that the airflow discharged from the combustion outlet 144 and the combustion-supporting gas port enters the conduit 170. Specifically, the conduit 170 is downstream of the jet of the combustion outlet 144. The gas enters the conduit 170 and flows until it flows to the end of the tube body 110.
[0037] In an optional embodiment, a reflux channel 171 is provided between the conduit 170 and the tube body 110. Specifically, the reflux channel 171 is located between the circumferential outer side of the conduit 170 and the inner wall of the tube body 110. This allows the post-combustion gas flow to pass through the conduit 170 and then flow in the opposite direction through the reflux channel 171. This creates an internal circulation of the flue gas. After the combustion gas is injected into the conduit 170, it continues to flow and is restricted by the inner wall of the tube body 110. It then turns back and flows through the reflux channel 171, where part of the flue gas continues to flow. The remaining part of the flue gas flows to the gap between the conduit 170 and the combustion outlet 144, creating an internal circulation of the flue gas. Residual fuel in the flue gas will also burn in this gap, further burning the residual fuel and achieving more complete combustion of the fuel.
[0038] In an optional embodiment, the combustion radiation tube 100 further includes a refractory material section 180. The refractory material section 180 is made of a refractory material. The refractory material includes alumina, chromium oxide or carbon, etc. Other refractory materials can also be used. The refractory material section 180 is provided on the tube wall of the tube body 110. The refractory material section 180 is located at the end of the tube body 110 near the combustion-supporting gas inlet 113. The thickness of the refractory material section 180 is greater than the thickness of the tube wall of the tube body 110, and can withstand a relatively high temperature. The gas inlet 113 is arranged in the refractory material section 180, and the refractory material section 180 is provided with a stepped curved channel, which connects the combustion-supporting gas inlet 113 with the above-mentioned airflow channel 153 and the first combustion-supporting gas port 142. The refractory material section 180 is provided with a flue gas outlet 114, and the flue gas outlet 114 is located next to the combustion-supporting gas inlet 113. A flue gas channel 154 is formed between the outer sleeve 150 and the tube body 110, and the flue gas outlet 114 is connected to the reflux channel 171 through the flue gas channel 154.
[0039] In an optional embodiment, the combustion radiant tube 100 further includes a plurality of heat conducting members 160, which are used to exchange heat between the flue gas in the flue gas passage 154 and the combustion-supporting gas in the airflow passage 153. The plurality of heat conducting members 160 are disposed around the wall of the outer sleeve 150 in multiple rows and columns. The plurality of heat conducting members 160 are arranged along both ends of the flue gas passage 154, with spaces between adjacent heat conducting members 160. The heat conducting members 160 may be made of thermoplastic carbon fiber composite material. The heat conducting members 160 have excellent heat transfer performance and heat resistance, and can effectively transfer the heat of the flue gas to the combustion-supporting gas in the airflow passage 153, thereby preheating the combustion-supporting gas. This effectively utilizes the waste heat of the flue gas to preheat the air, greatly recovering the flue gas heat and improving the overall thermal efficiency of the radiant tube.
[0040] During operation of the present application, a portion of the combustion air enters through the first combustion-supporting gas port 142 and is mixed and burned with the gas in the burner 130. The other portion of the combustion air flows through the airflow channel 153 and flows out through the second combustion-supporting gas outlet and the third combustion-supporting gas port 152 respectively, and is mixed and burned with the remaining gas, thereby achieving three-stage combustion of the combustion gas. The flue gas in the mixing combustion chamber 141 of the inner sleeve 140 is discharged from the combustion outlet 144 and then enters the conduit 170 until it reaches the end of the pipe column shield. It then flows back through the reflux channel 171 and finally flows to the flue gas outlet 114 through the flue gas channel 154. Part of the flue gas is returned to the internal conduit 170 due to the internal circulation of the flue gas caused by the flue gas jet. Since the three-stage air combustion and flue gas internal circulation are completed in the pipe body 110, and the flue gas waste heat is effectively utilized, the fuel can be burned more fully, the NOx emissions formed by combustion are reduced, and the overall thermal efficiency is improved.
[0041] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", "optional example" or "optional implementation" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.
[0042] In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.
[0043] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.
Claims
1. A combustion radiant tube, characterized in that: include: A pipe body (110) has a cavity (111) therein, and the pipe body (110) is provided with a fuel inlet (112), a combustion-supporting gas inlet (113), and a smoke outlet (114) communicating with the cavity (111); An inner sleeve (140) is located in the cavity (111), one end of the inner sleeve (140) is connected to the tube body (110) and is provided with a first combustion-supporting gas port (142), the other end of the inner sleeve (140) is provided with a combustion outlet (144) and a diffusion hole (143), a mixing combustion chamber (141) is provided inside the inner sleeve (140), the mixing combustion chamber (141) is used to mix fuel and combustion-supporting gas and provide a combustion space, one end of the mixing combustion chamber (141) is communicated with the combustion outlet (144), and the other end of the mixing combustion chamber (141) is communicated with the first combustion-supporting gas port (142) and the fuel inlet (112) respectively; An outer sleeve (150) is located in the cavity (111), and the outer sleeve (150) is sleeved outside the inner sleeve (140). An air flow channel (153) is provided between the outer sleeve (150) and the inner sleeve (140), one end of the air flow channel (153) is connected to the combustion-supporting gas inlet (113), and the other end of the air flow channel (153) is connected to the diffusion hole (143). A plurality of combustion-supporting gas ports are provided at the end of the outer sleeve (150) near the combustion outlet (144).
2. The combustion radiant tube according to claim 1, characterized in that: A second combustion-supporting gas port (151) and a third combustion-supporting gas port (152) are provided at the end of the outer sleeve (150), wherein the second combustion-supporting gas port (151) is adjacent to the combustion outlet (144), and the third combustion-supporting gas port (152) is spaced apart from the second combustion-supporting gas port (151).
3. The combustion radiant tube according to claim 2, characterized in that: The distance between the diffusion hole (143) and the second combustion-supporting gas port (151) is greater than the distance between the third combustion-supporting gas port (152) and the second combustion-supporting gas port (151), so that the fuel entering the air flow channel (153) through the diffusion hole (143) can flow to the second combustion-supporting gas port (151) and the third combustion-supporting gas port (152) along with the combustion-supporting gas in the air flow channel (153).
4. The combustion radiant tube according to claim 1, characterized in that: It also includes a fuel pipe (120) located in the cavity (111), one end of the fuel pipe (120) is connected to the fuel inlet (112), and the other end of the fuel pipe (120) is used to provide fuel to the mixing combustion chamber (141).
5. The combustion radiant tube according to claim 4, characterized in that: The invention also includes a burner (130) connected to the inner sleeve (140), wherein the mixed combustion chamber (141) is formed between the burner (130) and the combustion outlet (144), and a gap is provided between the burner (130) and the fuel pipe (120), so that the combustion-supporting gas passing through the first combustion-supporting gas port (142) can enter the mixed combustion chamber (141) together with the fuel at the gap.
6. The combustion radiant tube according to claim 1, characterized in that: The invention also includes a conduit (170) disposed in the cavity (111). The conduit (170) is located outside the end of the outer sleeve (150). The conduit (170) is arranged opposite to and spaced from the combustion outlet (144), so that the airflow discharged from the combustion outlet (144) and the combustion-supporting gas port enters the conduit (170).
7. The combustion radiant tube according to claim 6, characterized in that: A reflux channel (171) is provided between the conduit (170) and the tube body (110), so that the airflow after combustion passes through the conduit (170) and then flows in the reverse direction through the reflux channel (171).
8. The combustion radiant tube according to claim 7, characterized in that: The invention also includes a refractory material section (180) provided on the tube wall of the tube main body (110), the refractory material section (180) being located at the end of the tube main body (110) close to the combustion-supporting gas inlet (113), the refractory material section (180) being provided with the flue gas outlet (114), a flue gas channel (154) being formed between the outer sleeve (150) and the tube main body (110), and the flue gas outlet (114) being connected to the reflux channel (171) through the flue gas channel (154).
9. The combustion radiant tube according to claim 8, characterized in that: It also includes a plurality of heat-conducting members (160), which are used for heat exchange between the flue gas in the flue gas channel (154) and the combustion-supporting gas in the air flow channel (153). The plurality of heat-conducting members (160) are arranged around the tube wall of the outer sleeve (150), and the plurality of heat-conducting members (160) are arranged along both ends of the flue gas channel (154).
10. The combustion radiant tube according to any one of claims 1 to 9, characterized in that: The invention also includes a fuel flange (190) connected to the pipe body (110), and the fuel flange (190) has a fuel channel communicating with the fuel inlet (112).