High-speed oxygen lance for inhibiting generation of NOX under oxygen-enriched combustion working condition and use method

Abstract

The invention relates to a high-speed oxygen lance for inhibiting generation of NOX under an oxygen-enriched combustion working condition and a using method, the high-speed oxygen lance comprises a primary oxygen inlet pipe and a cooling pipe, and the cooling pipe is arranged outside the primary oxygen inlet pipe in a sleeving manner; a secondary oxygen inlet pipe is arranged between the primary oxygen inlet pipe and the cooling pipe in a sleeved mode, the outer wall of the primary oxygen inlet pipe and the inner wall of the secondary oxygen inlet pipe are fixedly connected through round steel spot welding, the outer wall of the secondary oxygen inlet pipe and the inner wall of the cooling pipe are fixedly connected through round steel spot welding, and a flange is arranged on the outer wall of the cooling pipe. An air inlet pipe A communicated with the secondary oxygen inlet pipe is arranged on the outer wall of the secondary oxygen inlet pipe, an air inlet pipe B communicated with the cooling pipe is arranged on the outer wall of the cooling pipe, and the upper end of the secondary oxygen inlet pipe and the upper end of the cooling pipe are both arranged in a sealed mode. A bidirectional oxygen supply high-speed oxygen lance combustion-supporting technology is provided, stable MILD oxygen-enriched combustion can be achieved in hearths of various width specifications, and the investment cost and the maintenance cost can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of oxygen-enriched combustion in steel rolling heating furnaces, and in particular to a method for inhibiting NO X The generated high-speed oxygen gun and its use method. Background Art

[0002] The steel rolling heating furnace is a key equipment in the steel industry process, and is also the main energy-consuming and pollutant-discharging equipment. Due to its unique technical advantages, the oxygen-enriched combustion technology is the easiest technology to achieve large-scale energy conservation and emission reduction for heating furnaces that mainly burn coal gas. However, under the oxygen-enriched combustion condition, NO X The concentration of NO generated will be significantly higher than that under conventional air-assisted combustion conditions, so it is necessary to strengthen the suppression of NO under oxygen-rich combustion conditions. X The study of the generation process is of great significance for promoting green, low-carbon, energy conservation and emission reduction.

[0003] In order to suppress NO X The existing technology adopts high-speed oxygen lance oxygen-enriched combustion technology, premixed oxygen in combustion-supporting air oxygen-enriched combustion technology and waste heat recovery combustion technology based on MILD (Moderate and Intense Low Oxygen Dilution) oxygen-enriched combustion, that is, a mild combustion mode under low oxygen dilution conditions. The high-temperature reflux flue gas in the furnace quickly preheats and dilutes oxygen and fuel, so that the combustion reaction can be diffused to a wider area, the temperature distribution is uniform, the flame peak temperature is suppressed, and NO X The amount generated is significantly reduced.

[0004] For example, the Chinese patent application number is CN201910940430.4, and the patent is titled "A heating furnace oxygen-enriched combustion system and its control method". Its content involves a heating furnace oxygen-enriched combustion system and its control method. The heating furnace is equipped with a preheating section, a heating section, a second heating section and a uniform heating section. The first heating section is equipped with a combustion system one, and the second heating section is equipped with a combustion system two. The combustion system one and the combustion system two are respectively composed of a plurality of burners and oxygen guns arranged on both sides of the furnace. The heating furnace oxygen-enriched combustion system also includes an oxygen-enriched concentration control system for controlling the combustion system one or controlling the combustion system one and the combustion system two at the same time; the oxygen-enriched concentration control system is composed of a furnace temperature detection module, a burner load calculation module, a gas volume control module and an oxygen concentration control module. The advantages of this invention patent are: organically combining the original combustion system of the heating furnace with the oxygen-enriched combustion technology, spraying high-speed oxygen through the oxygen gun, forming flameless combustion in the furnace, which can effectively improve the combustion efficiency of the heating furnace, reduce fuel consumption, optimize the temperature field distribution in the furnace and the temperature uniformity of the steel billet, and reduce NO X However, the disadvantage of the prior art is that the heating furnace oxygen-enriched combustion control system does not have an oxygen-enriched combustion technology for the oxygen lance to reduce NO emissions.X The technical solution for reducing NO generation is explained, that is, not all oxygen lances can achieve the goal of reducing NO X The emission reduction effect is closely related to the selection of oxygen lances, installation spacing and incident angle. For example, the test results show that when the incident angle of the oxygen lance is reduced from 105° to 45°, the exhaust outlet NO X Emission concentration from 2.92mg / m 3 Increased sharply to 438.59 mg / m 3 ; The installation distance between the oxygen gun and the burner is increased from 100mm to 175mm, and the exhaust outlet is NO X Emission concentration from 308.36mg / m 3 Rapidly decreased to 62.43 mg / m 3 , that is, the prior art has NO X Risk of exceeding emission concentration standards.

[0005] Another example is the Chinese patent application number CN202010772008.5, entitled "A Premixed Oxygen-Enriched Combustion System and Method for a Steel Rolling Heating Furnace", which involves a premixed oxygen-enriched combustion system for a heating furnace, including a heating furnace, a fuel system, and a combustion-supporting system. The heating furnace includes a preheating section, a heating section, and a soaking section. The heating section is provided with a flat flame burner in the heating section and a straight flame burner at the bottom of the heating section. The soaking section is provided with a flat flame burner in the soaking section and a straight flame burner at the bottom of the soaking section. The combustion-supporting system includes an oxygen pipeline, an oxygen valve group, a premixed oxygen-enriched combustion system 1, and a premixed oxygen-enriched combustion system 2. The oxygen in the oxygen pipeline is supplied to the premixed oxygen-enriched combustion system 1 and the premixed oxygen-enriched combustion system 2 respectively through the oxygen valve group. This invention patent combines the original combustion system of the steel rolling heating furnace with the premixed oxygen-enriched combustion technology, and realizes oxygen-enriched combustion of the whole furnace by controlling different oxygen concentrations of different burners in the premixed oxygen-enriched combustion system, thereby improving the combustion efficiency and heat transfer efficiency of the heating furnace, thereby increasing production capacity, saving fuel, and reducing investment costs. The disadvantage of this prior art is that for the traditional steel rolling heating furnace burner, directly premixing oxygen in the combustion-supporting air to achieve oxygen-enriched combustion will cause problems such as faster combustion rate, shorter flame, and more concentrated combustion high-temperature area. Studies have shown that due to the increase in oxygen-enriched concentration, the combustion process is more complete and the heat loss of smoke exhaust is reduced. The increase in combustion temperature promotes NO X Especially thermal NO X The generation of NO X The rapid increase in the production of NO X The generated concentration increases with the increase of oxygen-enriched concentration, that is, the oxygen-enriched combustion technology with premixed oxygen in the combustion air cannot suppress NO X The production of NO X Rapid increase in production.

[0006] Another example is the Chinese patent application number CN202210390795.6, entitled "Waste heat recovery steel rolling heating furnace based on MILD oxygen-enriched combustion and its heating method". This invention is a waste heat recovery steel rolling heating furnace based on MILD oxygen-enriched combustion and its heating method, which belongs to the field of metallurgical thermal energy engineering technology. The steel rolling heating furnace includes a preheating section, a heating section, a soaking section, an oxygen main pipe, a flue gas main pipe, a fuel main pipe, and a water vapor regulating device. The heating section is provided with several sections, including a heating section 1, a heating section 2, ... and a heating section n. The oxygen main pipe, the flue gas main pipe and the fuel main pipe are respectively connected to the preheating section, the heating section and the soaking section. The water vapor regulating device is arranged on the flue gas main pipe. The advantages of the invention are to realize MILD oxygen-enriched combustion through the transformation of the heating furnace, and to adopt a side-burning oxygen blowing graded combustion method, flexibly adjust the oxygen ratio, combine the oxygen-enriched combustion technology with gentle combustion, and apply it to the steel rolling heating furnace. It can give full play to the advantages of oxygen-enriched combustion technology in energy saving and emission reduction, and overcome the shortcomings of oxygen-enriched combustion technology, and greatly reduce the concentration of nitrogen oxides generated during the heating process of the steel billet and the oxidation burning rate of the steel billet after heating. However, the shortcomings of the prior art are: (1) The waste heat recovery technology uses a fan to mix part of the flue gas into the combustion air, so that the O2 partial pressure in the combustion air is reduced, and the method of controlling the flame temperature is used to suppress NO X Since the flue gas needs to be transported by heat-resistant fans and flow control devices, the investment cost is high and the maintenance cost is large. Therefore, it is not suitable for promotion and implementation from the perspective of economic cost; (2) Studies have shown that: NO X The amount of oxygen generated decreases as the angle between the oxygen lance and the furnace wall increases. The oxygen incident angle of this technology is an acute angle of 30° to 45°. The oxygen jet will quickly intersect with the gas jet and is not fully diluted by the flue gas, thus forming a large local high temperature area at the nozzle, which promotes NO X Especially thermal NO X The generation of NO X The results are shown in Table 1. (3) The maximum oxygen incident velocity of this technology is 160m / s. After conversion, the suction distance on one side of the furnace is 6.5m, which is suitable for heating furnaces with a width of less than 13m. When the furnace width exceeds 13m, a "blind area" will appear in the middle area, that is, the area where the oxygen gun jet cannot reach. This area cannot form the MILD oxygen-enriched combustion effect, the temperature distribution is uneven, and NO X High generation volume.

[0007] Table 1 NO at different incident angles X Generation

[0008] Oxygen incident angle (°) 30 45 60 75 90 <![CDATA[NO X Amount of generation (mg / m 3 )]]> 475.32 438.59 405.12 328.72 58.98

[0009] In summary, the shortcomings of the prior art are:

[0010] 1) The installation of the oxygen gun does not fully consider the impact of structural parameters such as the incident angle and installation spacing, and cannot achieve the MILD oxygen-enriched combustion effect well, which may cause NO X Emission concentration exceeds the standard;

[0011] 2) Oxygen-enriched combustion technology with premixed oxygen in the combustion air cannot suppress NO X The production of NO X Rapid increase in generation volume;

[0012] 3) The waste heat recovery technology based on MILD oxygen-enriched combustion requires the use of heat-resistant fans and flow control devices for flue gas transportation, which has high investment costs and high maintenance costs;

[0013] 4) In the prior art, the oxygen lance adopts axial oxygen supply, and the jet momentum is constrained by conditions such as the rated flow rate and the nozzle cross-sectional area. The maximum entrainment distance is generally 6.0 to 6.5 meters. When the furnace width exceeds 13 meters, the oxygen lance jet distance cannot cover the entire furnace, and the "blind spot" cannot form the MILD oxygen-rich combustion effect. Summary of the invention

[0014] The present invention provides a method for inhibiting NO in oxygen-rich combustion conditions. X The generated high-speed oxygen lance and its use method solve the problem in the prior art that the jet momentum of the high-speed oxygen lance with axial oxygen supply is constrained by conditions such as the rated flow rate and the nozzle cross-sectional area, and the maximum suction distance cannot cover a large width furnace space. A high-speed oxygen lance combustion-supporting technology with bidirectional oxygen supply is provided, which can not only realize stable MILD oxygen-enriched combustion in furnaces of various widths and specifications, but also reduce investment costs and maintenance expenses.

[0015] In order to achieve the above object, the present invention adopts the following technical solutions:

[0016] A method for inhibiting NO in oxygen-rich combustion conditions X The generated high-speed oxygen gun comprises a primary oxygen inlet pipe and a cooling pipe, wherein the primary oxygen inlet pipe is sleeved with a cooling pipe on the outside; a secondary oxygen inlet pipe is sleeved between the primary oxygen inlet pipe and the cooling pipe, the outer wall of the primary oxygen inlet pipe and the inner wall of the secondary oxygen inlet pipe are fixedly connected by round steel spot welding, the outer wall of the secondary oxygen inlet pipe and the inner wall of the cooling pipe are fixedly connected by round steel spot welding, and a flange is arranged on the outer wall of the cooling pipe; an inlet pipe A connected to the secondary oxygen inlet pipe is arranged on the outer wall of the secondary oxygen inlet pipe, an inlet pipe B connected to the cooling pipe is arranged on the outer wall of the cooling pipe, and the upper ends of the secondary oxygen inlet pipe and the cooling pipe are both sealed.

[0017] Furthermore, the upper end of the primary oxygen intake pipe is higher than the secondary oxygen intake pipe, the upper end of the secondary oxygen intake pipe is higher than the cooling pipe, the upper end of the secondary oxygen intake pipe is sealed and connected to the primary oxygen intake pipe, and the upper end of the cooling pipe is sealed and connected to the secondary oxygen intake pipe.

[0018] Furthermore, the primary oxygen intake pipe, cooling pipe, secondary oxygen intake pipe and round steel are all made of 1Cr18Ni9.

[0019] Furthermore, 1 to 3 groups of round steels are evenly spot-welded along the axial direction between the outer wall of the primary oxygen intake pipe and the inner wall of the secondary oxygen intake pipe, with each group having 3 to 6 round steels; and 1 to 3 groups of round steels are evenly spot-welded along the axial direction between the outer wall of the secondary oxygen intake pipe and the inner wall of the cooling pipe, with each group having 3 to 6 round steels.

[0020] Furthermore, the outer diameter of the primary oxygen intake pipe is 27mm-40mm, and the length is 750mm-1000mm; the outer diameter of the secondary oxygen intake pipe is 40mm-53mm, and the length is 650mm-900mm; the outer diameter of the cooling pipe is 55mm-68mm, and the length is 550mm-800mm.

[0021] Furthermore, the intake pipe A and the intake pipe B have the same size and specification, both are φ(13-26) mm×(0.8-1.2) mm, 85 mm-100 mm in length, and are made of 304 stainless steel.

[0022] A method for inhibiting NO in oxygen-rich combustion conditions X The method for using the generated high-speed oxygen lance is as follows: primary oxygen is introduced into the primary oxygen inlet pipe and injected axially along the primary oxygen inlet pipe, and secondary oxygen is injected radially from the inlet pipe A along the secondary oxygen inlet pipe to form a rotating airflow, and there is no mixing process between the primary oxygen and the secondary oxygen. The primary oxygen is injected into the furnace in a cylindrical shape, and the secondary oxygen is injected into the furnace in a ring shape. The primary oxygen and the secondary oxygen are respectively supplied from two oxygen valve groups; first, cooling air is supplied radially from the inlet pipe B along the cooling air inlet pipe, and then primary oxygen is introduced; when the maximum entrainment distance of the primary oxygen is less than 1 / 2 of the effective width of the furnace, the secondary oxygen supply valve group is opened to introduce secondary oxygen into the furnace, and the flow cross-sectional area of ​​the secondary oxygen is smaller than the flow cross-sectional area of ​​the primary oxygen; the installation distance between the cross-sectional center of the high-speed oxygen lance and the edge of the burner is controlled to be 175-225 mm, the incident angle of the high-speed oxygen lance is 90-105°, and the oxygen enrichment concentration is controlled to be 35%-40%.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1) Provide a high-speed oxygen lance combustion-supporting technology with two-way oxygen supply, which can not only achieve stable MILD oxygen-enriched combustion in furnaces of various widths and specifications, but also reduce investment costs and maintenance costs;

[0025] 2) Solve the problem that the jet momentum of the high-speed oxygen lance with axial oxygen supply in the prior art is constrained by the conditions such as the rated flow rate and the nozzle cross-sectional area, and the maximum entrainment distance cannot cover a wide furnace space;

[0026] 3) By limiting the optimal structural parameter values ​​of the installation spacing and incident angle of the high-speed oxygen lance, NOx can be suppressed under oxygen-rich combustion conditions X Produces the best results. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the high-speed oxygen lance with bidirectional oxygen supply according to the present invention.

[0028] Figure 2 It is a schematic diagram of the AA cross-sectional structure of the high-speed oxygen lance with bidirectional oxygen supply according to an embodiment of the present invention.

[0029] Figure 3 This is an example diagram of the simulation of the temperature field entrainment effect of the high-speed oxygen lance of the present invention.

[0030] Figure 4 This is an example diagram of the simulation of the entrainment effect of the flow field of the high-speed oxygen lance described in the present invention.

[0031] Figure 5 This is a NO generation concentration analysis diagram of the high-speed oxygen lance of the present invention at different installation intervals.

[0032] Figure 6 This is a NO generation concentration analysis diagram of the high-speed oxygen lance of the present invention at different incident angles.

[0033] Figure 7 This is an effective thermal analysis diagram of the high-speed oxygen lance of the present invention at different oxygen-rich concentrations.

[0034] In the figure: 1. Primary oxygen inlet pipe 2. Welding port 3. Secondary oxygen inlet pipe 4. Cooling pipe 5. Round steel A 6. Round steel B 7. Flange 8. Inlet pipe A 9. Inlet pipe B 10. Primary oxygen flow section 11. Secondary oxygen flow section 12. Cooling air flow section 13. Round steel B section 14. Round steel A section DETAILED DESCRIPTION

[0035] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0036] See Figure 1 , is a schematic diagram of the structure of the present invention. The present invention provides a method for inhibiting NO in oxygen-rich combustion conditions. XThe generated high-speed oxygen gun comprises a primary oxygen inlet pipe 1, a secondary oxygen inlet pipe 3 and a cooling pipe 4, wherein the primary oxygen inlet pipe 1 is sleeved with a cooling pipe 4 on its outer side; a secondary oxygen inlet pipe 3 is sleeved between the primary oxygen inlet pipe 1 and the cooling pipe 4, the outer wall of the primary oxygen inlet pipe 1 and the inner wall of the secondary oxygen inlet pipe 3 are fixedly connected by round steel spot welding, the outer wall of the secondary oxygen inlet pipe 3 and the inner wall of the cooling pipe 4 are fixedly connected by round steel spot welding, a flange 7 is provided on the outer wall of the cooling pipe 4, and the high-speed oxygen gun is vertically installed on the outer wall of the furnace wall of the heating furnace by bolt connection; an inlet pipe A8 connected to the secondary oxygen inlet pipe 3 is provided on the outer wall of the secondary oxygen inlet pipe 3, an inlet pipe B9 connected to the cooling pipe 4 is provided on the outer wall of the cooling pipe 4, and the upper ends of the secondary oxygen inlet pipe 3 and the cooling pipe 4 are seamlessly welded by a full welding process.

[0037] The upper end of the primary oxygen intake pipe 1 is higher than the secondary oxygen intake pipe 3, and the upper end of the secondary oxygen intake pipe 3 is higher than the cooling pipe 4. The upper end of the secondary oxygen intake pipe 3 is sealed and connected to the primary oxygen intake pipe 1 by a full welding process to form a welding port 2, and the upper end of the cooling pipe 4 is sealed and connected to the secondary oxygen intake pipe 3 by a full welding process to form a welding port 2.

[0038] The primary oxygen intake pipe 1, the cooling pipe 4 and the secondary oxygen intake pipe 3 are all made of 1Cr18Ni9, the round steel A5 and the round steel B6 are all made of 1Cr18Ni9, three groups of round steels B6 are evenly spot-welded along the axial direction between the outer wall of the primary oxygen intake pipe 1 and the inner wall of the secondary oxygen intake pipe 3, with 6 in each group, three groups of round steels A5 are evenly spot-welded along the axial direction between the outer wall of the secondary oxygen intake pipe 3 and the inner wall of the cooling pipe 4, with 6 in each group, the intake pipe A8 and the intake pipe B9 are made of 304 stainless steel, and the flange 7 is made of 304 stainless steel.

[0039] The primary oxygen intake pipe 1 has an outer diameter of 27 mm and a length of 750 mm, the secondary oxygen intake pipe 3 has an outer diameter of 40 mm and a length of 650 mm, and the cooling pipe 4 has an outer diameter of 55 mm and a length of 550 mm.

[0040] The intake pipe A8 and the intake pipe B9 have the same size specifications, both of which are φ13mm×0.8mm, 85mm in length, and are made of 304 stainless steel.

[0041] A method for inhibiting NO in oxygen-rich combustion conditions XThe generated high-speed oxygen gun is used in a method that primary oxygen is introduced into the primary oxygen inlet pipe 1 and injected axially along the primary oxygen inlet pipe 1, and secondary oxygen is injected radially from the inlet pipe A8 along the secondary oxygen inlet pipe 3 to create a rotating airflow. There is no mixing process between the primary oxygen and the secondary oxygen. The primary oxygen is injected into the furnace in a cylindrical shape, and the secondary oxygen is injected into the furnace in a circular shape. The primary oxygen and the secondary oxygen are supplied from two oxygen valve groups respectively; first, cooling air is supplied radially from the inlet pipe B9 along the cooling air inlet pipe 4 to cool the high-speed oxygen gun tube. The wall and improve the safety of use; then introduce primary oxygen. When the maximum entrainment distance of primary oxygen is less than 1 / 2 of the effective width of the furnace, the secondary oxygen supply valve group is opened to introduce secondary oxygen into the furnace, and the cross-sectional area of ​​the secondary oxygen flow is smaller than the cross-sectional area of ​​the primary oxygen flow, that is, the secondary oxygen entrainment distance must be able to make up for the furnace space that the maximum entrainment distance of the primary oxygen cannot diffuse. The installation distance between the center of the cross-section of the high-speed oxygen gun and the edge of the burner is controlled at 200mm, the incident angle of the high-speed oxygen gun is 90°, and the oxygen enrichment concentration is controlled at 35%. ;

[0042] The entrainment distance of the primary oxygen and the secondary oxygen is simulated in advance by using ANSYS Fluent software to simulate the entrainment effect of the furnace temperature field and the flow field. The entrainment effect diagram of the temperature field and the flow field is shown in the attached figure of the specification. Figure 3 and Figure 4 As shown: Figure 3 It indicates that the maximum entrainment distance of the flame temperature field of oxygen-assisted combustion is less than 1 / 2 of the effective width of the furnace; Figure 4 It indicates that the maximum entrainment distance of the oxygen-assisted combustion furnace gas flow field is ≧1 / 2 of the effective width of the furnace (the upper limit distance of the horizontal axis X is set to 1 / 2 of the effective width of the furnace);

[0043] By optimizing the key process parameters such as installation spacing, incident angle and oxygen enrichment concentration, the new high-speed oxygen lance oxygen combustion technology can be used to suppress NO X The best effect is generated. Due to the NO generated during the oxygen-rich combustion process X It is mainly NO and NO2, of which NO accounts for more than 95%. X When generating, we can mainly discuss the NO generation mechanism;

[0044] The installation spacing refers to the length of the center distance between the oxygen lance section and the burner section minus the radius of the burner section. The research results show that when the installation spacing is 175-225mm, the NO generation concentration is in the minimum range, with a value of 48.58-58.36mg / m 3 And ensure that the high-speed oxygen gun does not directly hit the support beam water pipe, see Figure 5 shown.

[0045] The incident angle refers to the angle between the incident direction of oxygen and the wall surface of the burner side furnace. The research results show that when the incident angle is 90-105°, the NO generation concentration is significantly lower than that under the acute angle condition. The NO generation concentration is in the minimum range, with a value of 2.57-46.52 mg / m 3 , see Figure 6 shown.

[0046] The oxygen enrichment concentration refers to the percentage of oxygen content when the combustion air is oxygen-enriched. The research results show that when the oxygen enrichment concentration increases from 21% to 40%, the effective heat absorbed by the cooling water of the cooling pipe 4 is in the maximum range when the oxygen enrichment concentration is 35-40%, and the value is 632.37-652.31KW. Figure 7 shown.

[0047] The following examples are implemented on the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following examples. The methods used in the following examples are conventional methods unless otherwise specified.

[0048] [Example 1]

[0049] When the effective width of the heating furnace is 12m, high coke mixed gas is used as fuel, and the calorific value is (1800±50)×4.18KJ / Nm 3 The primary oxygen and secondary oxygen are supplied in two ways, and are respectively depressurized to 0.35MPa by their respective oxygen valve groups and then sent to the entrance of the primary oxygen inlet pipe 1 and the entrance of the inlet pipe A8 of the high-speed oxygen gun. Figure 1 and Figure 2 .

[0050] 1) The design flow rate of the mixed gas burner is 800Nm 3 / h, excess air coefficient 1.05, oxygen enrichment concentration set at 35%, high-speed oxygen gun primary oxygen inlet pipe 1 outer diameter selected 27mm, pipe wall thickness 5mm, length selected 750mm; primary oxygen flow section 10 center distance to the edge of the mixed gas burner installation spacing selected 200mm; primary oxygen inlet pipe 1 material 1Cr18Ni9; primary oxygen flow 90Nm 3 / h, the primary oxygen flow cross-section area is 2.3×10 －4 m 2 The primary oxygen flow rate can reach 108m / s, and the maximum entrainment distance is 4.96m. Since the maximum entrainment distance is less than 1 / 2 of the effective width of the furnace, the secondary oxygen supply valve group should be opened, that is, secondary oxygen needs to be injected into the furnace.

[0051] 2) The outer diameter of the secondary oxygen inlet pipe 3 of the high-speed oxygen gun is selected as 40mm, the wall thickness is 5mm, and the length is selected as 650mm; the upper end of the secondary oxygen inlet pipe 3 is sealed and connected with the primary oxygen inlet pipe 1 by full welding process; round steel B6 is spot welded tightly to the inner wall of the secondary oxygen inlet pipe 3 and the outer wall of the primary oxygen inlet pipe 1, six in a group, evenly distributed around the pipe wall, a total of three groups of eighteen, the diameter of the cross section 13 of the round steel B is 1.5mm; the material of the secondary oxygen inlet pipe 3 is 1Cr18Ni9, and the material of the round steel B6 is 1Cr18Ni9; the secondary oxygen flow rate is 90Nm 3 / h, secondary oxygen flow cross-sectional area 11 1.2×10 －4 m 2 The secondary oxygen flow rate can reach 208m / s, and the maximum suction distance is 9.55m. Since the maximum suction distance is greater than 1 / 2 of the effective width of the furnace, the suction distance meets the furnace width requirements.

[0052] 3) The outer diameter of the high-speed oxygen gun cooling tube 4 is 55mm, the tube wall thickness is 5mm, and the length is 550mm; the cooling tube 4 and the secondary oxygen intake tube 3 are seamlessly welded by full welding process; round steel A5 is spot welded tightly to the inner wall of the cooling tube 4 and the outer wall of the secondary oxygen intake tube 3, six in a group, evenly distributed around the tube wall, a total of three groups of eighteen, the diameter of the round steel A section 14 is 2.5mm; the outer sleeve 4 is made of 1Cr18Ni9, and the round steel A5 is made of 1Cr18Ni9; the cooling air flow rate is 8Nm 3 / h, cooling air flow cross section 12 area 3.0×10 －4 m 2 The cooling air flow rate is 7.4m / s, which can extend the service life of the equipment and increase operational safety.

[0053] 4) Secondary oxygen enters through the intake pipe A8, and cooling air enters through the intake pipe B9; the intake pipe A8 and the intake pipe B9 have the same size specifications, both of which are: φ13mm×0.8mm, length 85mm, and are made of 304 stainless steel.

[0054] 5) Flange 7 is welded to cooling pipe 4, and the high-speed oxygen gun is vertically installed on the outer wall of the heating furnace through bolt connection, and the incident angle is 90°; the size specification of flange 7 is DN50, and the material is 304 stainless steel.

[0055] [Example 2]

[0056] When the effective width of the heating furnace is 18m, high coke mixed gas is used as fuel, and the calorific value is (1800±50)×4.18KJ / Nm 3 The primary oxygen and secondary oxygen are supplied in two ways, and are respectively depressurized to 0.35MPa by their respective oxygen valve groups and then sent to the entrance of the primary oxygen inlet pipe 1 and the entrance of the inlet pipe A8 of the high-speed oxygen gun. Figure 1and Figure 2 .

[0057] 1) The design flow rate of the mixed gas burner is 1000Nm 3 / h, excess air coefficient 1.05, oxygen enrichment concentration set at 40%, high-speed oxygen gun primary oxygen inlet pipe 1 outer diameter selected 27mm, pipe wall thickness 5mm, length selected 750mm; primary oxygen flow section 10 center distance mixed gas burner edge installation distance selected 175mm; primary oxygen inlet pipe 1 material 1Cr18Ni9; primary oxygen flow 133Nm 3 / h, the primary oxygen flow cross-section area is 2.3×10 －4 m 2 The primary oxygen flow rate can reach 160m / s, and the maximum entrainment distance is 7.35m. Since the maximum entrainment distance is less than 1 / 2 of the effective furnace width of 9m, the secondary oxygen supply valve group should be opened, that is, secondary oxygen needs to be injected into the furnace.

[0058] 2) The outer diameter of the secondary oxygen inlet pipe 3 of the high-speed oxygen gun is selected as 40mm, the wall thickness is 5mm, and the length is selected as 650mm; the upper end of the secondary oxygen inlet pipe 3 is sealed and connected with the primary oxygen inlet pipe 1 by full welding process; round steel B6 is spot welded tightly to the inner wall of the secondary oxygen inlet pipe 3 and the outer wall of the primary oxygen inlet pipe 1, six in a group, evenly distributed around the pipe wall, a total of three groups of eighteen, the diameter of the cross section 13 of round steel B is 1.5mm; the material of the secondary oxygen inlet pipe 3 is 1Cr18Ni9, and the material of round steel B6 is 1Cr18Ni9; the secondary oxygen flow rate is 133Nm 3 / h, secondary oxygen flow cross-sectional area 11 1.2×10 －4 m 2 The secondary oxygen flow rate can reach 308m / s, and the maximum suction distance is 14.15m. Since the maximum suction distance is greater than 1 / 2 of the effective furnace width of 9m, the suction distance meets the furnace width requirements.

[0059] 3) The outer diameter of the high-speed oxygen gun cooling tube 4 is 55mm, the tube wall thickness is 5mm, and the length is 550mm; the cooling tube 4 and the secondary oxygen intake tube 3 are seamlessly welded by full welding process; round steel A5 is spot welded tightly to the inner wall of the cooling tube 4 and the outer wall of the secondary oxygen intake tube 3, six in a group, evenly distributed around the tube wall, a total of three groups of eighteen, the diameter of the round steel A section 14 is 2.5mm; the outer sleeve 4 is made of 1Cr18Ni9, and the round steel A5 is made of 1Cr18Ni9; the cooling air flow rate is 8Nm 3 / h, cooling air flow cross section 12 area 3.0×10 －4 m 2 The cooling air flow rate is 7.4m / s, which can extend the service life of the equipment and increase operational safety.

[0060] 4) Secondary oxygen enters through the intake pipe A8, and cooling air enters through the intake pipe B9; the intake pipe A8 and the intake pipe B9 have the same size specifications, both of which are: φ13mm×0.8mm, length 85mm, and are made of 304 stainless steel.

[0061] 5) Flange 7 is welded to cooling pipe 4, and the high-speed oxygen gun is installed obliquely on the outer wall of the heating furnace through bolt connection, and the incident angle is 105°; the size specification of flange 7 is DN50, and the material is 304 stainless steel.

Claims

1. A method for inhibiting NO under oxygen-rich combustion conditions X The generated high-speed oxygen gun includes a primary oxygen inlet pipe and a cooling pipe, wherein the primary oxygen inlet pipe is provided with a cooling pipe on the outside; characterized in that: A secondary oxygen intake pipe is sleeved between the primary oxygen intake pipe and the cooling pipe, the outer wall of the primary oxygen intake pipe and the inner wall of the secondary oxygen intake pipe are fixedly connected by round steel spot welding, the outer wall of the secondary oxygen intake pipe and the inner wall of the cooling pipe are fixedly connected by round steel spot welding, and a flange is provided on the outer wall of the cooling pipe; an intake pipe A connected to the secondary oxygen intake pipe is provided on the outer wall of the secondary oxygen intake pipe, and an intake pipe B connected to the cooling pipe is provided on the outer wall of the cooling pipe, and the upper ends of the secondary oxygen intake pipe and the cooling pipe are both sealed.

2. A method for inhibiting NO under oxygen-rich combustion conditions according to claim 1 X The generated high-speed oxygen lance is characterized by: The upper end of the primary oxygen intake pipe is higher than the secondary oxygen intake pipe, the upper end of the secondary oxygen intake pipe is higher than the cooling pipe, the upper end of the secondary oxygen intake pipe is sealed and connected to the primary oxygen intake pipe, and the upper end of the cooling pipe is sealed and connected to the secondary oxygen intake pipe.

3. A method for inhibiting NO under oxygen-rich combustion conditions according to claim 1 X The generated high-speed oxygen lance is characterized by: The primary oxygen intake pipe, cooling pipe, secondary oxygen intake pipe and round steel are all made of 1Cr18Ni9.

4. A method for inhibiting NO under oxygen-rich combustion conditions according to claim 1 X The generated high-speed oxygen lance is characterized by: 1 to 3 groups of round steels are evenly spot-welded along the axial direction between the outer wall of the primary oxygen intake pipe and the inner wall of the secondary oxygen intake pipe, with each group having 3 to 6 round steels; 1 to 3 groups of round steels are evenly spot-welded along the axial direction between the outer wall of the secondary oxygen intake pipe and the inner wall of the cooling pipe, with each group having 3 to 6 round steels.

5. A method for inhibiting NO under oxygen-rich combustion conditions according to claim 1 X The generated high-speed oxygen lance is characterized by: The outer diameter of the primary oxygen intake pipe is 27mm-40mm, and the length is 750mm-1000mm. The outer diameter of the secondary oxygen intake pipe is 40mm-53mm, and the length is 650mm-900mm. The outer diameter of the cooling pipe is 55mm-68mm, and the length is 550mm-800mm.

6. A method for inhibiting NO under oxygen-rich combustion conditions according to claim 1 X The generated high-speed oxygen lance is characterized by: The intake pipe A and the intake pipe B have the same size and specification, both are φ(13-26) mm×(0.8-1.2) mm, 85 mm-100 mm in length, and are made of 304 stainless steel.

7. A method for inhibiting NO in oxygen-rich combustion conditions according to any one of claims 1 to 6. X The generated high-speed oxygen lance use method is characterized in that: Primary oxygen is introduced into the primary oxygen inlet pipe and injected axially along the primary oxygen inlet pipe, and secondary oxygen is injected radially from the inlet pipe A along the secondary oxygen inlet pipe to form a rotating airflow. There is no mixing process between the primary oxygen and the secondary oxygen. The primary oxygen is injected into the furnace in a cylindrical shape, and the secondary oxygen is injected into the furnace in a ring shape. The primary oxygen and the secondary oxygen are supplied from two oxygen valve groups respectively. First, cooling air is supplied radially from the inlet pipe B along the cooling air inlet pipe, and then primary oxygen is introduced. When the maximum entrainment distance of the primary oxygen is less than 1 / 2 of the effective width of the furnace, the secondary oxygen supply valve group is opened to introduce secondary oxygen into the furnace, and the cross-sectional area of ​​the secondary oxygen flow is smaller than the cross-sectional area of ​​the primary oxygen flow. The installation distance between the cross-sectional center of the high-speed oxygen lance and the edge of the burner is controlled to be 175-225 mm, the incident angle of the high-speed oxygen lance is 90-105°, and the oxygen enrichment concentration is controlled to be 35%-40%.

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