Pre-mix high energy efficiency radiant tube burner with special-shaped tube type finned tube double stroke heat exchanger

Abstract

The application discloses a premix high-energy-efficiency radiation tube burner with a special-shaped tube type finned tube double-stroke heat exchanger, which comprises a main burner, a main burner shell, a radiation tube, a metal expansion joint, a finned tube group heat exchanger, a heat exchanger shell, an air connecting pipe and a capillary tube heat exchanger. The main burner shell is connected with the combustion end of the radiation tube, the heat exchanger shell is connected with the smoke exhaust end of the radiation tube, the finned tube group heat exchanger is arranged in the smoke exhaust end of the radiation tube, the main burner is arranged on the burner end plate shell and extends into the radiation tube, the side of the main burner shell is connected with the heat exchanger shell through the metal expansion joint, one end of the air connecting pipe is arranged in the capillary tube heat exchanger and communicates with the air inlet pipe on the capillary tube heat exchanger, the other end of the air connecting pipe penetrates through the heat exchanger shell and extends into the finned tube group heat exchanger through the smoke exhaust port. The stable and uniform flame can be formed under the high temperature of the blast furnace, the smoke exhaust temperature is low, the ultra-low NOx smoke exhaust can be formed, and the energy consumption is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a premixed high-efficiency radiant tube burner with a double-stroke heat exchanger having special-shaped tubular finned tubes. Background Art

[0002] U\W self-preheating burner technology is a new, efficient, and clean combustion technology developed based on indirect heating and self-preheating technologies. Since its introduction, it has been widely used in the industrial sector, particularly in the metallurgical industry. With increasingly stringent domestic requirements for energy conservation and emission reduction, traditional U\W self-preheating burners no longer meet the energy conservation and emission reduction requirements for NOx emissions and energy consumption. Currently, conventional premixed combustion technology suffers from high exhaust temperatures and higher energy consumption than conventional burners. To further reduce energy consumption standards per ton of steel, reducing emissions, saving energy, and improving energy efficiency have become the primary approaches, with the goal of reducing "black carbon" emissions at the source as a reserve technology.

[0003] In the domestic steel and metallurgical industry, U\W type self-preheating burners are mainly used in annealing furnaces, horizontal galvanizing furnaces, normalizing furnaces and heat treatment furnaces with conventional combustion methods. The burners are arranged on the side of this type of burner. The power range of this type of burner is large, generally in the range of 60~300kw. The indirect heating technology of radiant tubes, especially in the limited space of U\W type radiant tube burners, is more technically difficult to save energy and reduce emissions. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a high-efficiency premixed radiant tube burner with a double-stroke heat exchanger with special-shaped finned tubes in response to the above-mentioned defects of the prior art. The burner can form a stable and uniform flame under high furnace temperature, have a low exhaust temperature and can form ultra-low NOx exhaust, thereby reducing energy consumption.

[0005] The technical solution adopted by the present invention to solve the above technical problems is:

[0006] A premixed high-efficiency radiant tube burner with a special-shaped finned tube double-stroke heat exchanger includes a main burner, a main burner housing, a radiant tube, a metal expansion joint, a finned tube heat exchanger, a heat exchanger housing, an air connecting pipe, and a capillary tube heat exchanger. The main burner housing is connected to the combustion end of the radiant tube, the heat exchanger housing is connected to the exhaust end of the radiant tube, the finned tube heat exchanger is disposed in the exhaust end of the radiant tube, and the main burner is disposed on the burner end plate housing and extends into the radiant tube.

[0007] The heat exchanger shell is provided with a flue gas inlet, a hot air outlet and a smoke exhaust port which are interconnected. The side of the main burner shell is connected to the hot air outlet on the heat exchanger shell through a metal expansion joint. The flue gas inlet of the heat exchanger shell is connected to the smoke exhaust end of the radiation tube. The smoke exhaust port of the heat exchanger shell is connected to one end of the capillary tube heat exchanger. One end of the air connecting pipe is arranged in the capillary tube heat exchanger and is connected to the air inlet pipe on the capillary tube heat exchanger. The other end of the air connecting pipe passes through the heat exchanger shell and extends into the fin tube group heat exchanger through the smoke exhaust port.

[0008] According to the above technical solution, the main burner includes an ignition burner, a burner end plate shell, a secondary gas channel, a tertiary gas channel and a gas inlet pipe. The burner end plate shell is arranged at one end of the main burner shell, and the other end of the main burner shell is connected to the radiant tube;

[0009] A cavity is provided on the inner side of the burner end plate shell, and a secondary gas channel and a tertiary gas channel are provided on the cavity. One end of the secondary gas channel and one end of the tertiary gas channel are connected to the cavity, and the other end of the secondary gas channel and the other end of the tertiary gas channel extend into the radiation tube. A gas inlet pipe is provided on the outer side of the burner end plate shell and is connected to the cavity. The ignition burner passes through the burner end plate shell and is welded and fixed to the burner end plate shell.

[0010] According to the above technical solution, the inner cavity of the main burner shell is connected to the mounting tube, which extends into the combustion end of the radiation tube. A heat insulation board is arranged horizontally in the mounting tube, and the end of the mounting tube is connected to the inner wall of the main burner shell. A castable is arranged on the side of the heat insulation board in the mounting tube close to the heat source. A premixing channel is arranged longitudinally in the mounting tube, one end of the premixing channel is connected to the secondary gas channel, and the other end of the premixing channel passes through the heat insulation board and the castable in sequence. The tertiary gas channel extends into the mounting tube and passes through the heat insulation board and the castable in sequence. An ignition burner channel is arranged longitudinally in the castable, and the ignition burner penetrates into the mounting tube and extends into the ignition burner channel.

[0011] According to the above technical solution, the heat exchanger shell includes a four-way shell and an ejector nozzle socket. The upper port of the four-way shell is connected to the capillary heat exchanger through the shell flange 1 via the smoke exhaust port. The lower port of the four-way shell is connected to the metal expansion joint through the shell flange 2 via the hot air outlet. The right port of the four-way shell is connected to the radiant tube through the shell flange 3 via the smoke inlet.

[0012] The ejector nozzle seat is arranged horizontally in the inner cavity of the four-way shell. The side of the ejector nozzle seat is connected to one end of the ejector nozzle through a thread, and the other end of the ejector nozzle is connected to the metal expansion joint. One end of the ejector nozzle seat is connected to the left port of the four-way shell, and the other end is connected to the fin tube group heat exchanger; the left port of the four-way shell is provided with a sealing plate.

[0013] According to the above technical solution, the fin-tube heat exchanger includes inner and outer fin tubes, fin tube connectors, and fin tube ball heads, and the two ends of the inner and outer fin tubes are connected to the fin tube connectors and the fin tube ball heads respectively.

[0014] According to the above technical solution, the fin-tube heat exchanger is cylindrical and extends deep into the radiation tube.

[0015] According to the above technical solution, the upper end of the capillary heat exchanger is connected to the exhaust pipe gas collecting box, which includes a reducer with flanges welded at both ends. One end of the reducer is connected to the external exhaust pipe through a flange, and the other end is connected to the capillary heat exchanger through a flange. A threaded pipe is connected to the side of the reducer, and a valve is provided on the threaded pipe.

[0016] According to the above technical scheme, the capillary heat exchanger includes an inner sleeve, an outer sleeve, an air inlet pipe, a capillary heat exchanger outlet air collecting box and a capillary heat exchanger air collecting box inlet. The inner sleeve is arranged in the outer sleeve, and the tube walls of the inner sleeve and the outer sleeve are provided with an interlayer. The heat exchanger capillary is arranged in the interlayer of the inner sleeve, and the interlayer of the outer sleeve serves as the combustion-supporting air inlet air collecting box cavity. The capillary heat exchanger outlet air collecting box and the capillary heat exchanger air collecting box inlet are respectively arranged at the upper end and the lower end of the inner sleeve. The inlet air collecting box cavity is connected to the capillary heat exchanger air collecting box inlet through an annular seam. The capillary heat exchanger air collecting box inlet is a circular cavity, which is sealed and welded to one end of the heat exchanger capillary, and the other end of the heat exchanger capillary is sealed and welded to the capillary heat exchanger outlet air collecting box; the air inlet pipe is arranged on the outer sleeve and connected to the interlayer of the outer sleeve. The air inlet pipe is used to connect to the external combustion-supporting air duct.

[0017] According to the above technical solution, the outer sleeve includes shell one and shell two, and shell two is arranged in shell one; the inner sleeve includes shell three and shell four, and shell four is arranged in shell three. Shell four is welded to the outlet air collecting box of the capillary heat exchanger, and flange one and flange two are sealed and welded at both ends of shell one to form the combustion air inlet air collecting box cavity with shell two.

[0018] According to the above technical solution, the air connecting pipe includes a connecting pipe flange, a metal bellows and a connecting pipe. One end of the connecting pipe flange is sealed and connected to the capillary heat exchanger outlet air collecting box, the other end of the connecting pipe flange is connected to one end of the metal bellows, the other end of the metal bellows is connected to one end of the connecting pipe, and the other end of the connecting pipe passes through the ejector nozzle seat and penetrates into the inner cavity of the fin tube group heat exchanger.

[0019] The present invention has the following beneficial effects:

[0020] 1. While retaining the inherent advantages of its own preheating burner, the present invention creatively adds a capillary heat exchanger, and the combustion air enters the capillary heat exchanger, which fully increases the heat exchange area. An air connecting pipe is creatively added, and one end of the connecting pipe penetrates into the interior of the fin tube heat exchanger. The present invention can form a stable and uniform flame under high furnace temperature, low exhaust temperature and ultra-low NOx exhaust, and reduce energy consumption.

[0021] 2. The combustion air first enters shell 1 and shell 2. Its first function is to increase the heat exchange contact area, and its second function is to cool the heat exchanger shell. The combustion air enters the capillary heat exchanger, which consists of 100 tubes to form a capillary tube for fully preheating the combustion air. The capillary tube is flat in shape, which fully increases the heat exchange area. An air connecting pipe is creatively added. One end of the connecting pipe extends deep into the interior of the fin tube heat exchanger, but it is a free structure. A metal bellows is added at the other end to connect with the free expansion end of the capillary heat exchanger to avoid a short service life due to inconsistent thermal expansion. Shells 3 and 4 are creatively added for flue gas diversion, so that the flue gas preheats the air according to a certain stroke. Finned tube heat exchange is creatively added to further preheat the preheated combustion air. Because the combustion air in this section already has a certain temperature, conventional heat-resistant steel pipes can no longer meet the temperature requirements. The material of this section is further improved to meet on-site needs. A premixing channel is creatively added so that all preheated combustion air passes through the premixing channel. Local coal gas passes through the secondary gas channel in a certain proportion with the preheated combustion air, so that the combustion air is in excess of a certain proportion. After uniform mixing, the premixed gas mixture is ejected at high speed from the premixing channel. The ignition burner ignites the premixed gas mixture. The excess air ratio and the high-speed ejection of the mixed gas cause the ignition mixed gas to form a combustion reaction without local high temperature or flamelessness, thereby reducing NOx generation. An independent tertiary gas channel is creatively added. The tertiary gas channel extends a certain distance so that the ejected coal gas and the mixture with a certain residual oxygen after the combustion reaction in the mixing channel can undergo a combustion reaction again, thereby reducing NOx generation. An ignition burner is creatively added. The air and gas pipelines of the ignition burner are independent. When the furnace temperature is low, the ignition burner ignites the main burner. When the furnace temperature reaches a certain temperature, the ignition burner is extinguished, and the premixed air and gas mixture is ignited by the furnace temperature. This type of burner has a wide power adjustment range. Burners of different specifications can achieve heating capacities ranging from 40 to 300 kW and can be widely used in metallurgical quenching, annealing and heat treatment fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the structure of a premixed high-efficiency radiant tube burner with a double-pass heat exchanger with a special-shaped finned tube according to an embodiment of the present invention;

[0023] Figure 2 1 is a schematic structural diagram of a capillary heat exchanger in an embodiment of the present invention;

[0024] Figure 3 2 is a schematic structural diagram of a smoke exhaust pipe gas collecting box according to an embodiment of the present invention;

[0025] Figure 4 2 is a schematic structural diagram of an air connecting pipe according to an embodiment of the present invention;

[0026] Figure 5 1 is a schematic structural diagram of a fin-tube heat exchanger according to an embodiment of the present invention;

[0027] Figure 6 1 is a schematic structural diagram of a heat exchanger shell according to an embodiment of the present invention;

[0028] Figure 7 Schematic diagram of the structure of the main burner in an embodiment of the present invention;

[0029] Figure 8 1 is a schematic structural diagram of a heat exchanger capillary tube according to an embodiment of the present invention;

[0030] Figure 9 yes Figure 8 A top view of

[0031] Figure 10 This is a front view of an ignition burner in an embodiment of the present invention;

[0032] Figure 11 yes Figure 10 A top view of

[0033] Figure 12 This is a schematic structural diagram of the mounting tube in an embodiment of the present invention;

[0034] In the figure, 1 - exhaust pipe gas box, 2 - capillary heat exchanger, 3 - air connecting pipe, 4 - heat exchanger shell, 5 - finned tube heat exchanger, 6 - metal expansion joint, 7 - ignition burner, 8 - burner end plate shell, 9 - tertiary gas channel, 10 - main burner shell, 11 - mounting tube, 12 - premixing channel, 13 - gas inlet pipe, 14 - radiant tube, 15 - secondary gas channel, 16 - thermal insulation board, 17 - castable;

[0035] 1.2-reducing joint, 1.3-threaded pipe welded on the side of the reducing joint, 1.4-valve;

[0036] 2.1-Flange 1, 2.2-End cover, 2.3-Capillary heat exchanger outlet air box, 2.4-Shell 2, 2.5-Shell 1, 2.6-Air inlet pipe, 2.7-Heat exchanger capillary tube, 2.8-Shell 3, 2.9-Shell 4, 2.10-Capillary heat exchanger air box inlet, 2.11-Flange 2;

[0037] 3.1-Connecting pipe flange, 3.2-Metal bellows, 3.3-Connecting pipe;

[0038] 4.1-shell flange 1, 4.2-four-way shell, 4.3-shell castable, 4.4-injection nozzle socket, 4.5-shell flange 2, 4.6-shell flange 3;

[0039] 5.1- fin tube connector, 5.2- internal and external fin tube, 5.3- fin tube ball joint;

[0040] 6.1-Expansion joint flange 1, 6.2-Bellows, 6.3-Inner core pipe, 6.4-Expansion joint flange 2;

[0041] 71 - ignition electrode, 72 - air shell, 73 - gas shell, 76 - ignition burner pipe, 77 - mixing body. DETAILED DESCRIPTION

[0042] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0043] Reference Figures 1 to 12 As shown, a premixed high-efficiency radiant tube burner with a special-shaped finned tube double-stroke heat exchanger in one embodiment of the present invention includes a main burner, a main burner housing 10, a radiant tube 14, a metal expansion joint 6, a finned tube heat exchanger 5, a heat exchanger housing 4, an air connecting pipe 3 and a capillary tube heat exchanger 2. The main burner housing 10 is connected to the combustion end of the radiant tube 14 via a flange, and the heat exchanger housing 4 is connected to the exhaust end of the radiant tube 14 via a flange. The finned tube heat exchanger 5 is disposed in the exhaust end of the radiant tube 14, and the main burner is disposed on the burner end plate housing 8 and extends into the radiant tube 14.

[0044] The heat exchanger shell 4 is provided with a flue gas inlet, a hot air outlet and a smoke exhaust port which are interconnected. The side of the main burner shell 10 is connected to the hot air outlet on the heat exchanger shell 4 via a metal expansion joint 6. The flue gas inlet of the heat exchanger shell 4 is connected to the smoke exhaust end of the radiation tube 14. The smoke exhaust port of the heat exchanger shell 4 is connected to one end of the capillary tube heat exchanger 2. One end of the air connecting pipe 3 is arranged in the capillary tube heat exchanger 2 and is connected to the air inlet pipe 2.6 on the capillary tube heat exchanger 2. The other end of the air connecting pipe 3 passes through the heat exchanger shell 4 and extends into the finned tube group heat exchanger 5 through the smoke exhaust port.

[0045] Furthermore, the main burner includes an ignition burner 7, a burner end plate housing 8, a secondary gas channel 15, a tertiary gas channel 9, and a gas inlet pipe 13. The burner end plate housing 8 is bolted to one end of the main burner housing 10, and the other end of the main burner housing 10 is connected to the radiation tube 14.

[0046] A cavity is provided on the inner side of the burner end plate housing 8. A secondary gas channel 15 and a tertiary gas channel 9 are installed in the cavity via seal welding. One end of the secondary gas channel 15 and one end of the tertiary gas channel 9 are connected to the cavity. The other ends of the secondary gas channel 15 and the other ends of the tertiary gas channel 9 extend into the radiant tube 14. A gas inlet pipe 13 is installed on the outer side of the burner end plate housing 8 via seal welding and is connected to the cavity. One end of the ignition burner 7 protrudes from the burner end plate housing 8, and the other end passes through the burner end plate housing 8 and the main burner housing 10 and is welded to the burner end plate housing 8. The ignition burner 7 does not communicate with the cavity.

[0047] Furthermore, the inner cavity of the main burner shell 10 is connected to a mounting tube, which extends into the combustion end of the radiation tube. A heat insulation board 16 is transversely provided in the mounting tube 11, and the end of the mounting tube is communicated with the inner wall of the main burner shell 10. A castable 17 is provided on the side of the heat insulation board in the mounting tube close to the heat source. A premixing channel 12 is longitudinally provided in the mounting tube 11, and one end of the premixing channel is connected to the secondary gas channel 15. The other end of the premixing channel passes through the heat insulation board 16 and the castable 17 in sequence. The outer end of the premixing channel is flush with the outer end of the castable 17. The tertiary gas channel 9 extends into the mounting tube 11 and passes through the heat insulation board 16 and the castable 17 in sequence. An ignition burner channel is longitudinally provided in the castable, and the ignition burner 7 penetrates into the mounting tube 11 and extends into the ignition burner channel.

[0048] Furthermore, the ignition burner 7 and the tertiary gas channel 9 are both sheathed with a sleeve, one end of the sleeve is sealed to the bottom of the cavity, and the other end is sealed to the insulation board, ensuring that most of the preheated combustion air is ejected through the premixing channel 14.

[0049] Furthermore, the ignition burner 7 includes a mixing body 77, and the ignition gas inlet, ignition air inlet, outlet and installed ignition electrode 71 of the mixing body 77 are respectively connected to the ignition gas pipe, air shell 72, ignition burner pipe 76 and high-voltage package.

[0050] Furthermore, the ignition burner 7 has a T-shaped structure. The ignition burner pipe 76 of the ignition burner 7 passes through the burner end plate shell 8 and is welded and fixed. At the same time, it passes through the heat insulation board 16. The end of the ignition burner 7 leaks out of the heat insulation board 16 and the castable material for a certain distance. The other end of the ignition burner 7 is connected to the high-voltage package, the ignition burner air pipe, and the ignition burner gas pipe through the ignition electrode 71, the air shell 72, and the gas shell 73 respectively; the burner end plate shell 8 has a circular trapezoidal structure and has a cavity inside.

[0051] The gas inlet pipe 13, secondary gas channel 15, and tertiary gas channel 1 are respectively sealed and welded to the burner end plate shell 8, and the cavities are interconnected. The other end of the gas inlet pipe 13 is connected to the main burner gas pipe 71, and the other end of the secondary gas channel 15 extends a certain distance into the premixing channel 12. The tertiary gas channel 9 extends a certain distance through the insulation board 11. The burner end plate shell 8 is fixed to the main burner shell 10 by connecting bolts.

[0052] Furthermore, the main burner shell 10 is in the form of a three-way structure and is bolted to the burner end plate shell 8. The main burner shell 10 is interconnected with the heat exchanger shell 4 through the expansion joint 6. At the same time, the main burner shell 10 and the heat exchanger shell 4 are installed and fixed on the radiation tube and are interconnected. The inner circle is welded and fixed with a heat insulation plate; the heat insulation plate is rectangular, and one end is sealed and welded to the main burner shell 10, extending into the interior of the radiation tube 14. The premixing channel 12 is welded and fixed to the interior of the heat insulation plate. The tertiary gas channel 4 and the ignition burner 7 pass through the heat insulation plate and extend into the interior of the radiation tube 14.

[0053] Furthermore, the heat exchanger housing 4 includes a four-way housing and an ejector nozzle socket 4.4. The upper port of the four-way housing is connected to the capillary heat exchanger 2 via a housing flange 1 4.1 through a smoke exhaust port. The lower port of the four-way housing is connected to the metal expansion joint 6 via a housing flange 2 4.5 through a hot air outlet. The right port of the four-way housing is connected to the radiant tube 14 via a housing flange 3 4.6 through a smoke inlet.

[0054] The ejector nozzle seat 4.4 is arranged horizontally in the inner cavity of the four-way shell. The side of the ejector nozzle seat 4.4 is connected to one end of the ejector nozzle by a thread, and the other end of the ejector nozzle is connected to the metal expansion joint 6. One end of the ejector nozzle seat 4.4 is connected to the left port of the four-way shell, and the other end is connected to the fin tube group heat exchanger 5 by sealing welding; the left port of the four-way shell is provided with a sealing plate.

[0055] Furthermore, the heat exchanger shell 4 is composed of a shell flange 1 4.1, a four-way shell 4.2, a shell castable 4.3, an ejector nozzle base 4.4, a shell flange 2 4.5, a shell flange 3 4.6, etc. The heat exchanger shell 4 is a four-way structure, and is connected to the capillary heat exchanger 2, the metal expansion joint 6, and the W-shaped radiant tube through the shell flange 1 4.1, the shell flange 2 4.5, and the shell flange 3 4.6 respectively. The side of the ejector nozzle base 4.4 is connected to the ejector nozzle through a thread, and the end is sealed and welded to the fin tube group heat exchanger 5.

[0056] Furthermore, the fin-tube heat exchanger 5 includes inner and outer fin tubes 5.2, fin tube connectors 5.1, and fin tube ball heads 5.3. The two ends of the inner and outer fin tubes 5.2 are respectively connected to the fin tube connectors 5.1 and the fin tube ball heads 5.3 by sealing welding; the fin tube connectors 5.1 are connected to the ejector nozzle seat 4.4.

[0057] Furthermore, the fin-tube heat exchanger 5 is cylindrical and extends deep into the radiation tube 14 .

[0058] Furthermore, the lower end of the capillary heat exchanger 2 is connected to the heat exchanger shell 4 through flange 2.11, and the upper end of the capillary heat exchanger 2 is connected to the exhaust pipe gas collecting box 1 through flange 1 2.1. The exhaust pipe gas collecting box 1 includes a reducer 1.2, which is in a frustum shape. Flanges are welded at both ends of the reducer 1.2. One end of the reducer 1.2 is connected to the external exhaust pipe through a flange, and the other end is connected to the capillary heat exchanger 2 through a flange. A threaded pipe 1.3 is welded to the side of the reducer, and a valve 1.4 is provided on the threaded pipe 1.3; the large end of the reducer 1.2 is connected to the external exhaust pipe, and the small end is connected to the capillary heat exchanger 2. The reducer 1.2 is in a frustum shape.

[0059] Furthermore, the capillary heat exchanger 2 includes an inner sleeve, an outer sleeve, an air inlet pipe 2.6, a capillary heat exchanger outlet air collecting box 2.3 and a capillary heat exchanger air collecting box inlet 2.10. The inner sleeve is arranged in the outer sleeve, and the pipe walls of the inner sleeve and the outer sleeve are both provided with an annular interlayer. A plurality of heat exchanger capillaries 2.7 are arranged in the interlayer of the inner sleeve. The interlayer of the outer sleeve serves as the combustion air inlet air collecting box cavity. The capillary heat exchanger outlet air collecting box 2.3 is provided with a plurality of heat exchanger capillaries 2.7. .3 and the capillary heat exchanger gas collecting box inlet 2.10 are respectively arranged at the upper and lower ends of the inner sleeve. The combustion air inlet gas collecting box cavity is connected to the capillary heat exchanger gas collecting box inlet 2.10 through an annular seam at the bottom of the interlayer. The capillary heat exchanger gas collecting box inlet 2.10 is a circular cavity and is seal-welded to one end of the heat exchanger capillary tube 2.7. The other end of the heat exchanger capillary tube 2.7 is seal-welded to the capillary heat exchanger outlet gas collecting box 2.3.

[0060] The air inlet pipe 2.6 is arranged on the outer sleeve and is connected to the interlayer of the outer sleeve. The air inlet pipe 2.6 is used to connect to the external combustion air duct. The lower end of the inner cavity of the heat exchanger capillary tube 2.7 is connected to the inlet 2.10 of the capillary heat exchanger gas collecting box, and the upper end of the inner cavity of the heat exchanger capillary tube 2.7 is connected to the capillary heat exchanger outlet gas collecting box 2.3. An annular cavity is left between the inner sleeve and the outer sleeve, and the outer wall of the inner sleeve interlayer is provided with a flow hole, so that the inner sleeve interlayer is connected to the annular cavity between the inner sleeve and the outer sleeve.

[0061] Furthermore, an end cover plate 2.2 is provided at the upper end of the capillary tube heat exchanger outlet air collecting box 2.3, and the end cover plate is connected to the capillary tube heat exchanger outlet air collecting box 2.3 by bolts.

[0062] Furthermore, the outer sleeve includes shell 1 2.5 and shell 2 2.4, and shell 2 2.4 is sleeved in shell 1 2.5; the inner sleeve includes shell 3 2.8 and shell 4 2.9, and shell 4 2.9 is sleeved in shell 3 2.8. Shell 4 2.9 is welded to the capillary heat exchanger outlet air collecting box 2.3, and flange 1 2.1 and flange 2 2.11 at both ends of shell 1 2.5 are sealed and welded with shell 2 2.4 to form the combustion air inlet air collecting box cavity.

[0063] Furthermore, the shell 1 2.5, the shell 2 2.4, the shell 3 2.8 and the shell 4 2.9 are all cylindrical.

[0064] Furthermore, shell four 2.9 is welded to the capillary heat exchanger outlet air collecting box 2.3 and placed inside the circle formed by the heat exchanger capillary 2.7, and shell three 2.8 is welded to the capillary heat exchanger air collecting box inlet 2.10 and placed outside the circle formed by the heat exchanger capillary 2.7.

[0065] The heat exchanger capillary tubes 2.7 include horizontal flat tubes and vertical flat tubes that are interconnected and alternately arranged along the same straight line.

[0066] Furthermore, the air connecting pipe 3 includes a connecting pipe flange 3.1, a metal bellows 3.2 and a connecting pipe 3.3. One end of the connecting pipe flange 3.1 is sealedly connected to the capillary heat exchanger outlet air collecting box 2.3, the other end of the connecting pipe flange 3.1 is connected to one end of the metal bellows 3.2, the other end of the metal bellows 3.2 is connected to one end of the connecting pipe 3.3, and the other end of the connecting pipe 3.3 passes through the ejector nozzle seat 4.4 and penetrates into the deepest part of the inner cavity of the fin tube group heat exchanger 8.

[0067] Furthermore, the connecting pipe 3.3 is L-shaped, and the elbow of the connecting pipe 3.3 passes through the ejector nozzle seat 4.4 and is welded and fixed to the ejector nozzle seat 4.4.

[0068] Furthermore, the smoke exhaust pipe air collecting box 1 is in a frustum shape, the air connecting pipe 3 is in an L-shaped structure, and the capillary heat exchanger 2 is in a cylindrical structure.

[0069] Furthermore, the radiation tube is a U-shaped radiation tube or a W-shaped radiation tube.

[0070] Working principle of the present invention: In order to better understand the present invention, the technical solution of the present invention is further explained in conjunction with the embodiments and drawings. Figures 1 to 8 According to the present invention, a premixed high-efficiency radiant tube burner with a special-shaped finned tube double-stroke heat exchanger is implemented, which mainly includes a main burner, a metal expansion joint 6, a finned tube group heat exchanger 5, an air connecting pipe 3, a capillary heat exchanger 2, an exhaust pipe gas box 1, a heat exchanger shell 4, and an ejector nozzle.

[0071] The capillary heat exchanger is composed of flange 1, end cover plate, capillary heat exchanger outlet air collecting box, shell 2, shell 1, air inlet pipe, heat exchanger capillary, shell 3, shell 4, capillary heat exchanger inlet air collecting box, and flange 2 welded and threaded. In the capillary heat exchanger, normal temperature combustion air enters the inner cavity of heat exchanger shell 1 and shell 2 through the air inlet pipe for the first combustion air preheating, and can reduce the temperature of heat exchanger shell 1. Shell 1 and the capillary heat exchanger inlet air collecting box form an annular seam structure, and the preheated combustion air is sprayed into the capillary heat exchanger inlet air collecting box, and the combustion air is evenly distributed in each special-shaped tube. The special-shaped tube is made of heat-resistant steel pipe and is processed and extruded from 0Cr25Ni20 material, so that the inside of the steel pipe changes from round to flat, which increases the contact area of ​​the combustion air and reduces the preheating temperature gradient of the combustion air. Except for shell 1, the overall structure of the heat exchanger has expansion capacity to avoid cracking due to temperature difference. The heat exchanger is designed with a labyrinth-shaped flue gas guide channel formed by shell three and shell four, so that the high-temperature flue gas can contact the special-shaped tube as much as possible, forming strong convection and enhancing the heat exchange efficiency of the heat exchanger.

[0072] The finned tube heat exchanger consists of finned tube connectors, finned tube bulbs, finned tubes, etc. The finned tube bulbs and finned tubes are made of 0Cr28Ni48W5, which are non-oxidizing under normal use at 1180°C, with a continuous use temperature of 1250°C and a maximum temperature of 1350°C. The finned tube connectors are made of 0Cr25Ni20. The finned tube heat exchanger, air connecting pipe and radiant tube form a double-layer annular seam structure. The combustion air enters the heat exchanger through the air connecting pipe and fully contacts the finned tubes, achieving sufficient heat exchange. The flue gas contacts the outer fins of the finned tubes, achieving sufficient heat exchange and improving energy utilization. The flue gas is discharged through the combustion air guide pipe and introduced into the burner housing through the expansion joint. It is mixed with the coal gas through the premixing channel and enters the radiant tube for combustion reaction.

[0073] The air connecting pipe is composed of a connecting pipe flange, a metal bellows, and a connecting pipe. The connecting pipe and the metal bellows are made of 0Cr25Ni20, and the connecting pipe flange is made of 0Cr19Ni9. A metal bellows is added at one end to connect with the free expansion end of the capillary heat exchanger to avoid cracking due to inconsistent thermal expansion. The combustion air preheated by the capillary heat exchanger enters the air connecting pipe from this end, and the other end penetrates into the interior of the fin tube heat exchanger, with a distance of 20-40mm from the inner wall of the fin tube ball head. The preheated combustion air is sprayed onto the inner wall of the ball head to play a cooling and heat exchange role, further preheating the combustion air.

[0074] The ignition burner is assembled by ignition electrode, air shell, gas shell, mixture and pipeline. The ignition electrode is composed of iron-aluminum alloy wire and 95% alumina ceramic. The long-term use temperature of iron-aluminum alloy is not lower than 1250℃, and the surface oxidation rate is low and the strength is high under high temperature conditions. The 95% alumina ceramic is a special-shaped part with a bevel on the side. The bevel and the pipeline cooperate to make the air-gas mixture form a swirling gas and form a stable flame structure. The 95% alumina ceramic has insulation and high temperature resistance. The air shell and gas shell are precisely machined from brass. The straight hole diameter, pipeline diameter and bevel size are determined according to the burner power and fuel composition.

[0075] The heat shield is composed of pipes, annular plates, assembly plates, and castables. Premix channels are welded to the assembly plates. The premix channels, assembly plates, annular plates, and pipes are made of 0Cr25Ni20 material and are finely processed and molded. They are rated for a long-term use temperature of 1000°C, a continuous use temperature of 1150°C, and a maximum temperature of 1250°C. The castables are made of heavy-grain castables and are rated for a long-term use temperature of 1380°C, a continuous use temperature of 1450°C, and a maximum temperature of 1650°C. The aperture and number of premix channels welded to the assembly plates are determined by the burner power, fuel composition, and radiant tube diameter. The number of premix channels is limited to 2-3, and the tertiary gas channels and premix channels are symmetrically assembled.

[0076] The burner endplate shell is machined from a high-temperature resistant alloy. The gas inlet pipe, secondary gas channel, and tertiary gas channel are welded to the burner endplate shell. The gas inlet pipe is threaded at one end and chamfered and welded to the burner endplate shell at the other end. The secondary gas channel is machined from 0Cr25Ni20 pipe and rod, with precision beveled and straight holes at the end. The beveled holes account for 70% of the area, while the straight holes account for 30%. The total aperture area is determined by the burner power, gas flow rate, and composition. The bevel angle of the beveled holes is determined by the inner diameter of the premixing channel and the depth of the secondary gas channel into the premixing channel. The number of beveled holes is determined by the diameter of the gas nozzle to ensure uniform mixing. The tertiary gas channel is machined from 0Cr25Ni20 and 0Cr28Ni48W5 pipe and rod, with straight holes at the end. The depth of the tertiary gas channel beyond the insulation board is determined by the inner diameter of the radiant tube and the flow rate of the air-gas mixture, ensuring that the air-gas mixture is mostly burned before mixing with the gas ejected from the tertiary gas channel. The local high temperature in the flame area is reduced, thereby reducing NOx generation and improving the uniformity of the radiation tube surface. The tertiary gas channel and the outside of the ignition burner are equipped with pipes, one end of which is continuously sealed and welded to the burner end plate shell, and the other end is assembled and sealed with the insulation board to ensure that most of the combustion air after preheating is ejected through the premixing channel.

[0077] The present invention employs a premixed combustion, high-efficiency U / W-type radiant tube burner with a special-shaped tube, a finned tube, and a double-stroke heat exchanger. The burner is secured to the heating equipment via a burner housing, a heat exchanger housing, and a radiant tube mounting flange. Valves are installed on the main burner gas line, the ignition gas line, the main burner gas line, the ignition burner air line, and the main burner air line. These valves adjust the air and gas flow rate and ratio of each burner to achieve a desired combustion effect. Before igniting the burner, the pilot burner air line valve is adjusted to the appropriate position. When the controller receives the ignition command, it controls the high-voltage coil to discharge, igniting the ignition electrode. Simultaneously, the valve on the pilot burner gas line opens, allowing gas to flow into the pilot burner, where it mixes with the combustion-supporting air flowing into the burner and burns, forming a stable, specifically shaped flame. First open the air pipeline and then open the main burner gas pipeline after a certain interval. The ignition burner ignites the main burner. As the furnace temperature rises and reaches a certain temperature, the ignition burner gas pipeline and air pipeline valve are closed to allow the combustion air and gas premixing channel of part of the flue gas to be introduced. The air-gas mixture is ignited through the high-temperature atmosphere inside the radiation tube. The first step of combustion uses excess air to reduce the local high temperature of the flame and reduce NOx generation. The second step is to reduce the oxygen concentration in the combustion air by introducing inert gas into the flue gas on the basis of the first step, reduce the local high temperature of the flame and thus reduce NOx generation. The third step is to burn the residual oxygen in the mixture after the burner with the gas on the basis of the first and second steps, further reduce NOx generation and reduce flue gas temperature emissions. The flame temperature is evenly distributed, and NO x It generates low emissions and can be widely used in heating and heat treatment fields that require pulse combustion control and continuous adjustment.

[0078] The above are only preferred embodiments of the present invention, and certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention still fall within the scope of protection of the present invention.

Claims

1. A premixed high-efficiency radiant tube burner with a double-stroke heat exchanger with a special-shaped finned tube, characterized in that: The main burner comprises a main burner, a main burner housing (10), a radiant tube (14), a metal expansion joint (6), a finned tube heat exchanger (5), a heat exchanger housing (4), an air connecting pipe (3) and a capillary tube heat exchanger (2), wherein the main burner housing (10) is connected to the combustion end of the radiant tube (14), the main burner is arranged on the burner end plate housing (8) and extends into the radiant tube (14), the heat exchanger housing (4) is connected to the exhaust end of the radiant tube (14), and the finned tube heat exchanger (5) is arranged in the exhaust end of the radiant tube (14); The heat exchanger shell (4) is provided with a flue gas inlet, a hot air outlet and a smoke exhaust port which are interconnected. The side of the main burner shell (10) is connected to the hot air outlet on the heat exchanger shell (4) through a metal expansion joint (6). The flue gas inlet of the heat exchanger shell (4) is connected to the smoke exhaust end of the radiation tube (14). The smoke exhaust port of the heat exchanger shell (4) is connected to one end of the capillary heat exchanger (2). One end of the air connecting pipe (3) is arranged in the capillary heat exchanger (2) and is connected to the air inlet pipe (2.6) on the capillary heat exchanger (2). The other end of the air connecting pipe (3) passes through the heat exchanger shell (4) and extends into the finned tube group heat exchanger (5) through the smoke exhaust port. The upper end of the capillary heat exchanger (2) is connected to a smoke exhaust pipe gas collecting box (1), and the smoke exhaust pipe gas collecting box (1) includes a reducing joint (1.2). Flanges are welded to both ends of the reducing joint (1.2). One end of the reducing joint (1.2) is connected to an external smoke exhaust pipe via a flange, and the other end is connected to the capillary heat exchanger (2) via a flange. A threaded pipe (1.3) is connected to the side of the reducing joint, and a valve (1.4) is provided on the threaded pipe (1.3). The capillary heat exchanger (2) includes an inner sleeve, an outer sleeve, an air inlet pipe (2.6), a capillary heat exchanger outlet air collecting box (2.3) and a capillary heat exchanger air collecting box inlet (2.10). The inner sleeve is arranged in the outer sleeve. The tube walls of the inner sleeve and the outer sleeve are both provided with an annular interlayer. A plurality of heat exchanger capillaries (2.7) are provided in the interlayer of the inner sleeve. The interlayer of the outer sleeve serves as a combustion air inlet air collecting box cavity. The capillary heat exchanger outlet air collecting box (2.3) and the capillary heat exchanger air collecting box inlet (2.10) are respectively arranged at the upper end and the lower end of the inner sleeve. The combustion air inlet air collecting box cavity and the capillary heat exchanger air collecting box inlet (2.10) are connected through an annular seam at the bottom of the interlayer. The capillary heat exchanger air collecting box inlet (2.10) ) is an annular cavity, which is sealed and welded to one end of the heat exchanger capillary tube (2.7), and the other end of the heat exchanger capillary tube (2.7) is sealed and welded to the capillary heat exchanger outlet gas collecting box (2.3); an air inlet pipe (2.6) is provided on the outer sleeve and is communicated with the interlayer of the outer sleeve, and the air inlet pipe (2.6) is used to connect to the external combustion-supporting air duct, the lower end of the inner cavity of the heat exchanger capillary tube (2.7) is communicated with the inlet (2.10) of the capillary heat exchanger gas collecting box, and the upper end of the inner cavity of the heat exchanger capillary tube (2.7) is communicated with the capillary heat exchanger outlet gas collecting box (2.3), an annular cavity is left between the inner sleeve and the outer sleeve, and a flow hole is provided on the outer wall of the inner sleeve interlayer, so that the inner sleeve interlayer is communicated with the annular cavity between the inner sleeve and the outer sleeve; The heat exchanger shell (4) includes a four-way shell and an ejector nozzle seat (4.4). The upper port of the four-way shell is connected to the capillary heat exchanger (2) through the shell flange 1 (4.1) via the smoke exhaust port. The lower port of the four-way shell is connected to the metal expansion joint (6) through the shell flange 2 (4.5) via the hot air outlet. The right port of the four-way shell is connected to the radiation tube (14) through the shell flange 3 (4.6) via the smoke inlet. The ejector nozzle seat (4.4) is arranged transversely in the inner cavity of the four-way shell. The ejector nozzle seat (4.4) is connected to one end of the ejector nozzle by a threaded connection on the side. The other end of the ejector nozzle is connected to the metal expansion joint (6). One end of the ejector nozzle seat (4.4) is connected to the left port of the four-way shell, and the other end is connected to the fin tube group heat exchanger (5). The left port of the four-way shell is provided with a sealing plate. The outer sleeve includes shell one (2.5) and shell two (2.4), and shell two (2.4) is sleeved in shell one (2.5); the inner sleeve includes shell three (2.8) and shell four (2.9), and shell four (2.9) is sleeved in shell three (2.8). Shell four (2.9) is welded to the capillary heat exchanger outlet air collecting box (2.3), and flange one (2.1) and flange two (2.11) are sealed and welded at both ends of shell one (2.5) to form a combustion air inlet air collecting box cavity with shell two (2.4), and a flow hole is provided on the side wall of shell three (2.8).

2. The premixed high-efficiency radiant tube burner with a double-pass heat exchanger with a special-shaped finned tube according to claim 1 is characterized in that: The main burner comprises an ignition burner (7), a burner end plate shell (8), a secondary gas channel (15), a tertiary gas channel (9) and a gas inlet pipe (13); the burner end plate shell (8) is arranged at one end of the main burner shell (10), and the other end of the main burner shell (10) is connected to the radiation tube (14); A cavity is provided on the inner side of the burner end plate shell (8), and a secondary gas channel (15) and a tertiary gas channel (9) are provided on the cavity, and one end of the secondary gas channel (15) and one end of the tertiary gas channel (9) are connected to the cavity, and the other end of the secondary gas channel (15) and the other end of the tertiary gas channel (9) extend into the radiation tube (14). A gas inlet pipe (13) is provided on the outer side of the burner end plate shell (8) and is connected to the cavity; one end of the ignition burner (7) is exposed outside the burner end plate shell (8), and the other end passes through the burner end plate shell (8) and the main burner shell (10), and is welded and fixed to the burner end plate shell (8).

3. The premixed high-efficiency radiant tube burner with a double-pass heat exchanger with a special-shaped finned tube according to claim 2 is characterized in that: The inner cavity of the main burner shell (10) is connected to a mounting tube, which extends into the combustion end of the radiation tube. A heat insulation board (16) is transversely arranged in the mounting tube (11), and the end of the mounting tube is communicated with the inner wall of the main burner shell (10). A castable (17) is provided on the side of the heat insulation board in the mounting tube close to the heat source. A premixing channel (12) is longitudinally arranged in the mounting tube (11), one end of the premixing channel is connected to the secondary gas channel (15), and the other end of the premixing channel passes through the heat insulation board (16) and the castable (17) in sequence. The tertiary gas channel (9) extends into the mounting tube (11) and passes through the heat insulation board (16) and the castable (17) in sequence. An ignition burner channel is longitudinally arranged in the castable. The ignition burner (7) passes into the mounting tube (11) and extends into the ignition burner channel.

4. The premixed high-efficiency radiant tube burner with a double-pass heat exchanger with a special-shaped finned tube according to claim 1 is characterized in that: The fin tube heat exchanger (5) comprises inner and outer fin tubes (5.2), fin tube connectors (5.1), and fin tube ball heads (5.3), wherein both ends of the inner and outer fin tubes (5.2) are respectively connected to the fin tube connectors (5.1) and the fin tube ball heads (5.3).

5. The premixed high-efficiency radiant tube burner with a double-pass heat exchanger with a special-shaped finned tube according to claim 1 is characterized in that: The finned tube heat exchanger (5) is cylindrical and extends deep into the interior of the radiation tube (14).

6. The premixed high-efficiency radiant tube burner with a double-pass heat exchanger with a special-shaped finned tube according to claim 1 is characterized in that: The air connecting pipe (3) includes a connecting pipe flange (3.1), a metal bellows (3.2) and a connecting pipe (3.3). One end of the connecting pipe flange (3.1) is sealed and connected to the capillary heat exchanger outlet air collecting box (2.3). The other end of the connecting pipe flange (3.1) is connected to one end of the metal bellows (3.2). The other end of the metal bellows (3.2) is connected to one end of the connecting pipe (3.3). The other end of the connecting pipe (3.3) passes through the ejector nozzle seat (4.4) and penetrates into the inner cavity of the finned tube group heat exchanger (5).

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