Anti-flashback burner nozzle, burner and working method

Abstract

The present invention discloses an anti-flashback burner nozzle, a burner and a working method. The anti-flashback burner nozzle of the present invention comprises a nozzle and a delivery channel arranged below the nozzle; the nozzle comprises an adjustment channel, a plurality of spray holes located on the side wall of the adjustment channel, an adjustment mechanism for blocking the spray holes, a support mechanism for supporting the adjustment mechanism and a nozzle top located above the adjustment channel; the adjustment mechanism moves upward along the adjustment channel under the action of the upward airflow, the spray holes located on the side wall of the adjustment channel open, and the airflow enters the outside of the adjustment channel from the spray holes. The burner nozzle of the present invention ensures the safety of exhaust gas combustion, meets the performance of high exhaust gas flow rate, low temperature control, no flashback and timely pressure relief, ensures that the temperature of the flame is not transmitted in the opposite direction of the exhaust gas pipeline flow, and ensures that the exhaust gas pipeline is not ignited.

Description

Technical Field

[0001] The invention relates to the field of petrochemical waste gas purification, and in particular to an anti-flashback burner nozzle, a burner and a working method. Background Art

[0002] The burner nozzle is a key part of the gas / waste gas combustion device, and is commonly found in various combustion-related industrial equipment, such as: direct-fired boilers, regenerative combustion devices, garbage incinerators and waste heat boilers. A burner with good performance can reasonably organize the mixing of fuel and oxidant (such as air) to achieve safe and stable combustion and ensure sufficient combustion efficiency and heat. For some special petrochemical devices, it is also necessary to meet the needs of flexible adjustment of flame length, combustion ignition temperature, heating temperature and heat load. According to the mixing method of gas fuel and air, it can be divided into three categories, namely diffusion combustion, partial premixed combustion and complete premixed combustion. According to the flue gas outlet velocity of the fire channel, it can be divided into low-speed burners and high-speed burners. The nozzle flow rate of the low-speed burner is less than 50m / s; the nozzle flow rate of the high-speed burner is higher than 50m / s, generally 200-300m / s.

[0003] The fully premixed burner mixes the gas and air before entering the combustion chamber. The gas and air are mixed evenly, the combustion is complete and more stable, and less incomplete combustion occurs. Because more air is added, the combustion pressure is higher, and a low-pressure fan is required to assist combustion. The fully premixed burner is prone to flashback when the flow rate is low, so strict requirements are placed on the calorific value and density of the gas before design, the adjustment is more centralized, and anti-flashback devices are installed; the heat load of a single burner is small; the noise is large, especially when operating at high pressure and high load, it is more obvious.

[0004] Partial premix burners mix part of the air (20%-80% of primary air) before combustion. A part of the mixed combustion-air mixture burns directly after leaving the burner, while the rest of the gas burns by diffusion and mixing with the surrounding air. Partial premix burners are generally designed in the form of a single nozzle. When the combustion load is large, it is easy to cause flameout or flameout. The nozzle head can also be designed in the form of multiple fire holes, but it requires higher pressure.

[0005] In the diffusion combustion method, air and fuel are separated before combustion, and air is supplied during the combustion process. The fuel and air are mixed and burned at the contact surface. According to the air supply method, it can be divided into natural induced draft and forced blast. Natural induced draft is mostly used for civil purposes, with low nozzle injection speed and small investment. Forced blast combustion is mainly used in industrial applications. This burner has a complex structure and requires forced blast. The design and manufacturing costs are high, and the combustion effect is more stable.

[0006] The exhaust gas contains some air, accounting for 0-98%. There are fewer combustible components in the exhaust gas. This part of the exhaust gas is in the range of non-spontaneous combustion, flammable, and explosive. The combustion mode is diffusion combustion, partial premixed combustion, and full premixed combustion. When deflagration occurs, flashback is likely to occur, so a stable and safe combustion method is needed to reduce the occurrence of accidents. This burner has the functions of anti-flashback and stable combustion. Summary of the invention

[0007] Purpose of the invention: In order to solve the problems of the prior art, the present invention provides a flashback burner nozzle, a burner and a working method.

[0008] Technical solution: The anti-flashback burner nozzle described in the present invention includes a nozzle and a conveying channel arranged below the nozzle; the nozzle includes an adjustment channel, a plurality of spray holes located on the side wall of the adjustment channel, an adjustment mechanism for blocking the spray holes, a supporting mechanism for supporting the adjustment mechanism, and a nozzle top located above the adjustment channel; the adjustment mechanism moves upward along the adjustment channel under the action of the upward airflow, the spray holes located on the side wall of the adjustment channel open, and the airflow enters the outside of the adjustment channel from the spray holes.

[0009] In order to ensure the safety of exhaust gas combustion, the exhaust gas needs to have the performance of high flow rate, low temperature control, no backfire, and timely pressure relief. The anti-backfire burner nozzle of the present invention ensures that the temperature of the flame is not transmitted in the opposite direction of the exhaust gas pipeline flow, no backfire occurs, and the exhaust gas pipeline is not ignited.

[0010] As a preferred structure of the present invention, the adjustment mechanism is a cone-shaped body, including an upper vertebral body, a lower vertebral body and a cylindrical blocking body located between the upper vertebral body and the lower vertebral body.

[0011] As a preferred structure of the present invention, the conical body of the adjusting mechanism has a hollow cavity, and the size of the hollow cavity can be adjusted.

[0012] As a preferred structure of the present invention, the top of the nozzle is a hollow cavity protruding upward, and the height of the top of the nozzle is not less than the total height of the upper vertebral body and the blocking body.

[0013] As a preferred structure of the present invention, the nozzle top includes a nozzle upper cover fitted with the upper vertebral body and a nozzle lower cover fitted with the blocking body.

[0014] As a preferred structure of the present invention, the diameters of the plurality of spray holes gradually increase in the upward direction.

[0015] As a preferred structure of the present invention, the supporting mechanism is a supporting step arranged below the adjusting channel.

[0016] As a preferred structure of the present invention, a threaded ring is arranged below the adjustment channel.

[0017] As a preferred structure of the present invention, a plurality of layers of fire-blocking metal plates and a large threaded ring located above the conveying channel are arranged in the conveying channel.

[0018] As a preferred structure of the present invention, the fire-blocking metal disk includes multiple layers of fire-blocking units, each of which is a coaxially arranged cylinder with a corrugated structure, and a narrow channel is arranged between each layer of fire-blocking units.

[0019] That is, the fire-blocking unit is composed of multiple layers of thin plates arranged in concentric circles, each layer of thin plates is a curled (corrugated) cylinder, and there are narrow channels between each layer of thin plates. The thickness of the thin plates is 0.1-0.3mm, and each layer of thin plates has corrugations at the same position every 0.2-1.2mm.

[0020] The outer diameter of the fire-retardant metal disc is consistent with the inner diameter of the conveying channel, and the two are fitted together. The fire-retardant metal disc has multiple layers of the same structure, and one to three layers can be set according to different pressures. When flashback occurs, the flame will pass through a tortuous channel, thereby reducing the speed of flashback and playing a role in fire retardancy.

[0021] The present invention also provides a burner comprising the anti-flashback burner nozzle.

[0022] The working method of the anti-flashback burner nozzle of the present invention comprises the following steps:

[0023] (S1) Exhaust gas enters the conveying channel, passes through several layers of fire-retardant metal plates, and then enters the regulating channel. Under the action of pressure, the regulating mechanism gradually separates from the supporting mechanism and rises along the regulating channel, gradually passing over several nozzle holes located on the side wall of the regulating channel. The opened nozzle holes begin to release gas and release pressure. When the flow rate and pressure release rate are stable, the regulating mechanism begins to stabilize;

[0024] (S2) When the pressure continues to rise, the regulating mechanism will continue to rise to open the blocked spray hole. When the flow rate and the pressure release rate are stable, a stable state is reached again.

[0025] (S3) As the pressure continues to increase, the regulating mechanism rises to the top of the nozzle, and all the nozzle holes spray exhaust gas, which is ignited by the fuel gas of the combustion furnace.

[0026] Beneficial effects: (1) The anti-flashback burner nozzle of the present invention can adapt to different exhaust gases, especially the exhaust gases from petrochemical and chemical enterprises. The exhaust gas components are complex, with air (or nitrogen) accounting for 0-98%, and the remaining components accounting for 0.5-10%. Hydrogen, methane, ethane and diesel components may exist, and the explosion range of each component is different. The anti-flashback burner nozzle of the present invention can be used safely within the explosion range; (2) The burner nozzle of the present invention ensures the safety of exhaust gas combustion, meets the performance of high exhaust gas flow rate, low temperature control, no flashback, and timely pressure relief, and ensures that the temperature of the flame is not transmitted in the opposite direction of the exhaust gas pipeline flow, no flashback occurs, and the exhaust gas pipeline is not ignited; (3) The fire-retardant metal disk of the present invention is in the form of a baffle, and the exhaust gas flows faster and longer therein. When a flashback tendency occurs, the combustion time is effectively prolonged, so that it can better exchange heat with the metal plate, thereby reducing the temperature of the combustible material and preventing it from reaching the ignition point, thereby eliminating the risk of ignition. (4) The regulating mechanism of the present invention cooperates with the regulating channel. After the spray hole is opened, the regulating mechanism is in a suspended rotating state and will not come into contact with the inner wall of the regulating channel to cause jamming. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the flame nozzle of the anti-flashback burner of the present invention;

[0028] Figure 2 It is a structural schematic diagram of the regulating mechanism of the present invention;

[0029] Figure 3 It is a structural schematic diagram of the flame nozzle of the anti-flashback burner of the present invention;

[0030] Figure 4 It is a structural schematic diagram of the flame nozzle of the anti-flashback burner of the present invention;

[0031] Figure 5 For the present invention Figure 1 AA section view of the burner nozzle;

[0032] Figure 6 For the present invention Figure 1 BB cross-section of the burner nozzle. DETAILED DESCRIPTION

[0033] Example 1: Figure 1-6As shown, the anti-flashback burner nozzle of the present invention comprises a nozzle 1 and a delivery channel 2 arranged below the nozzle 1. The anti-flashback burner nozzle of the present invention is a variable injection cross-section structure, the delivery channel 2 is the air inlet end of the exhaust gas; the nozzle 1 is arranged at the exhaust gas outlet end and has a plurality of spray holes; an adjustment mechanism 103 is arranged inside the nozzle 1. The variable injection cross-section structure of the present invention is specifically that the diameter of the delivery channel 2 is larger than the diameter of the nozzle 1, and the connection between the delivery channel 2 and the nozzle 1 is a transition zone with a gradually decreasing diameter.

[0034] The nozzle 1 includes an adjusting channel 101, a plurality of spray holes 102 located on the side wall of the adjusting channel 101, an adjusting mechanism 103 for blocking the spray holes 102, a supporting mechanism 104 for supporting the adjusting mechanism 103, and a nozzle top 105 located above the adjusting channel 101; the adjusting mechanism 103 moves upward along the adjusting channel 101 under the action of the upward airflow, the spray holes 102 located on the side wall of the adjusting channel 101 open, and the airflow enters the outside of the adjusting channel 101 from the spray holes 102.

[0035] The rising direction of the airflow is upward, and the apertures of the plurality of nozzles 102 gradually increase in the upward direction. The nozzles 102 are non-perpendicular to the pipe wall. In order to ensure the stability of the exhaust gas at a small gas volume, the aperture of the opening gradually increases in the direction of gas flow.

[0036] The adjustment mechanism 103 is a cone, which is stuck at the bottom of the nozzle 1 through the support mechanism 104, blocking the passage between the nozzle 1 and the delivery passage 2. The adjustment mechanism 103 includes an upper cone 1031, a lower cone 1032, and a cylindrical blocking body 1033 located between the upper cone 1031 and the lower cone 1032. When the exhaust gas passes through, the exhaust gas has a certain pressure, and the exhaust gas will cause the cone to float up and down. When the cone floats, it will float and rotate automatically due to the effect of the airflow, and the cone will not contact the delivery structure and nozzle of the exhaust gas.

[0037] As a preferred structure of the present invention, the support mechanism 104 is a step structure arranged at the bottom end of the nozzle 1, the lower vertebral body 1032 of the adjustment mechanism 103 clamps the support mechanism 104, and the outer diameter of the blocking body 1033 is the same as the inner diameter of the adjustment channel 101 of the nozzle 1.

[0038] As a preferred embodiment of the present invention, the expansion coefficients of the regulating mechanism 103 and the nozzle 1 of the present invention are different. The regulating mechanism 103 is made of low-expansion metals such as chromium, and the nozzle 1 is made of conventional stainless steel and alloy steel. As the temperature rises, the expansion of the regulating mechanism 103 is smaller than that of the nozzle 1, resulting in a gradual decrease in the friction between the outer wall of the regulating mechanism 103 and the inner wall of the nozzle 1. When the exhaust gas volume is small and unstable, causing a short-term contact, the outer wall of the regulating mechanism 103 and the inner layer structure of the nozzle 1 have a sufficiently small friction and will not cause jamming.

[0039] Furthermore, the present invention can adjust the center of gravity of the regulating mechanism 103 according to the type and pressure of the exhaust gas. The hollow structure of the regulating mechanism 103 can adjust the specific gravity of the regulating mechanism 103 and the center of gravity of the regulating mechanism 103 by adjusting the size of the hollow cavity, so as to have better stroke adjustment and injection channel. The aperture design of the spray hole 102 of the present invention enables the regulating mechanism 103 to be in a suspended rotating state when rising, and will not contact the inner wall of the nozzle 1 to cause jamming.

[0040] The nozzle top 105 is a hollow cavity protruding upward, and the height of the nozzle top 105 is not less than the total height of the upper cone 1031 and the blocking body 1033, ensuring that when the adjustment mechanism 103 moves to the top, all the spray holes 102 are opened. As a preferred mechanism of this embodiment, the nozzle top 105 includes a nozzle upper cover 1051 that can be fitted with the upper cone 1031 and a nozzle lower cover 1052 that can be fitted with the blocking body 1033.

[0041] In addition, a threaded ring 106 is provided below the adjustment channel 101 and can be disassembled. Several layers of fire-blocking metal discs 201 and a large threaded ring 202 located above the conveying channel 2 are provided in the conveying channel 2. The fire-blocking metal discs 201 are metal wire structures.

[0042] The outer diameter of the fire-blocking metal disk is consistent with the inner diameter of the conveying channel, and the two are fitted together. The fire-blocking metal disk 201 of the present invention includes multiple layers of fire-blocking units, each of which is a coaxially arranged cylinder with a corrugated structure, and a narrow channel is arranged between each layer of fire-blocking units. In the present embodiment, the fire-blocking unit is composed of several layers of thin plates arranged in concentric circles, each thin plate is a circular ring structure, and there are also narrow channels between the thin plates. The thickness of the thin plate is 0.1-0.3mm, and each layer of thin plates has corrugations at the same position every 0.2-1.2mm. The flow rate of the exhaust gas therein is faster and the flow time is long. When there is a tendency to flashback, the combustion time is effectively extended, so that it can better exchange heat with the metal plate, reduce the temperature of the combustible material, prevent it from reaching the ignition point, and there is no risk of ignition. Specifically, there are 1-3 layers of fire-blocking metal disks 201 in the burner nozzle of the present invention, and each layer of the fire-blocking metal disk 201 has a metal disk filler composed of multiple small channels. The flow rate into each small channel is greater than 15 m / s. The flow rate of the exhaust gas is large, and the flow speed is greater than the tempering speed, so there is no risk of tempering. The gaps between the metal plates are very small, and the flow rate of the exhaust gas in them is also fast; the channel area between the metal plates is large, which enhances the heat transfer, reduces the flame temperature to below the ignition point, and prevents the flame from spreading to the fuel gas, playing a role in fire prevention and tempering prevention.

[0043] The fire-blocking metal disk 201 of the present invention has a certain thickness. The two sides of the channel between the metal plates are called channel walls. The thicker the metal disk is. Combustion and explosion are not direct reactions between molecules, but are stimulated by external energy. The molecular bonds are destroyed, and activated molecules are generated. The activated molecules are split into short-lived but very active free radicals. The free radicals collide with other molecules to generate new products. At the same time, new free radicals are also generated and continue to react with other molecules. When the burning combustible gas passes through the narrow and long channel of the fire-blocking element, the collision probability of the free radicals with the channel wall increases, and the free radicals participating in the reaction decrease. When the channel of the flame arrester is narrow to a certain extent, the collision of the free radicals with the channel wall dominates. Due to the sharp decrease in the number of free radicals, the reaction cannot continue, that is, the combustion reaction cannot continue to propagate through the metal disk, which plays a role in fire blocking.

[0044] As a preferred structure, the conveying channel 2 of the present invention is a slender structure. The thinner the conveying channel is, the better the heat exchange with the air outside the outer wall of the conveying channel can be carried out, thereby reducing the temperature of the combustible material so that it does not reach the ignition point and there is no risk of ignition.

[0045] As a preferred implementation of this embodiment, the nozzle 1 is made of stainless steel or ultra-high temperature resistant material, such as 310S; the delivery channel 2 is made of stainless steel, the adjustment mechanism 103 is made of high temperature resistant metal such as 304, which will not deform; the fire-retardant metal plate is made of stainless steel. The specific type of stainless steel is selected according to the different components of the exhaust gas.

[0046] The working method of the anti-flashback burner nozzle comprises the following steps:

[0047] When the device has the conditions for ignition and combustion, introduces exhaust gas and ignites it, the exhaust gas first enters the anti-backfire burner nozzle through the fan, and the exhaust gas first enters the channel formed by the outer wall of the conveying channel 2, and then enters the fire-retardant metal plate 201 with a multi-layer structure. When entering the adjustment channel 101 formed by the outer wall of the nozzle 1, because the fan provides air pressure, under the action of pressure, the adjustment mechanism 103 will gradually separate from the support mechanism 104 and rise. After rising to a certain extent, the adjustment mechanism 103 will slowly pass over the spray hole 102, and the spray hole 102 begins to discharge air and release pressure. When the flow rate and the pressure release rate are stable, the adjustment mechanism 103 begins to stabilize.

[0048] When the pressure of the fan continues to rise, the regulating mechanism 103 will first pass over the spray hole 102 with a smaller aperture, and then pass over the spray hole 102 with a larger aperture. When the flow rate and the pressure release rate are stable, a stable state is reached again.

[0049] When the fan is fully opened, the adjustment mechanism 103 is at the uppermost end, and all the nozzles spray exhaust gas, which is ignited by the fuel gas of the combustion furnace. After the components in the exhaust gas are burned out, they are discharged from the upper part of the device.

[0050] The burner structure described in this embodiment includes the above-mentioned anti-flashback burner nozzle. The specific scope of use of the burner using the anti-flashback burner nozzle is the waste gas treatment in petrochemical enterprises. The waste gas components of petrochemical and chemical enterprises are complex, with air (or nitrogen) accounting for 0-98%, and the remaining components accounting for 0.5-10%. The components are complex, and hydrogen, methane, ethane and diesel components may exist, and the explosion range of each component is different. The anti-flashback burner nozzle of the present invention can also be used safely within the explosion range. The normal flow rate of waste gas designed for the anti-flashback burner nozzle of the present invention is 50-200 meters / second, and the minimum design flow rate should not be less than 15 meters / second.

[0051] When the gas flow rate at the exhaust gas end of the anti-flashback burner nozzle of the present invention is greater than 15m / s, the exhaust gas flow rate has a passive adjustment function and meets the flow rate condition of 10-110%; because the exhaust gas flow rate is greater than the flame flashback combustion speed, the burner has an anti-flashback function. The exhaust gas delivery structure of the burner nozzle of the present invention is cold combustion air on the outside, and the cold combustion air cools the exhaust gas. The exhaust gas end is composed of multiple burners with a large heat exchange area, ensuring that the temperature of the exhaust gas during flashback combustion is not higher than 90°C, the exhaust gas temperature is lower than the ignition point, and the burner has flame-retardant and flame-retardant functions.

[0052] The flame temperature of the burner nozzle of the present invention is controlled at 760-840°C, the heat resistance temperature is 1400°C, and the non-methane total hydrocarbons are controlled at ≯20mg / m 3 , NOx content control ≯50mg / m 3 The above content index is calculated based on the 3% oxygen content in GB31570-2015 and GB31571-2015 standards. After combustion, the removal rate of non-methane total hydrocarbons in the present invention is above 99%, meeting the requirements of national standards GB31570-2015 and GB31571-2015.

[0053] The burner of the present invention has a service life of ≥10 years, is simple to install and maintain, and can better provide good environmental protection effects and safety advantages for the combustion unit.

[0054] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A flashback-proof burner nozzle, characterized in that: The invention comprises a nozzle (1) and a conveying channel (2) arranged below the nozzle (1); the nozzle (1) comprises an adjusting channel (101), a plurality of spray holes (102) located on the side wall of the adjusting channel (101), an adjusting mechanism (103) for blocking the spray holes (102), a supporting mechanism (104) for supporting the adjusting mechanism (103), and a nozzle top (105) located above the adjusting channel (101); the adjusting mechanism (103) moves upward along the adjusting channel (101) under the action of an upward airflow, the spray holes (102) located on the side wall of the adjusting channel (101) open, and the airflow enters the outside of the adjusting channel (101) from the spray holes (102).

2. The anti-flashback burner nozzle according to claim 1, characterized in that: The regulating mechanism (103) is a cone-shaped body, comprising an upper cone (1031), a lower cone (1032), and a cylindrical blocking body (1033) located between the upper cone (1031) and the lower cone (1032).

3. The anti-flashback burner nozzle according to claim 2, characterized in that: The nozzle top end (105) is a hollow cavity protruding upward, and the height of the nozzle top end (105) is not less than the total height of the upper cone (1031) and the blocking body (1033).

4. The anti-flashback burner nozzle according to claim 2, characterized in that: The nozzle top end (105) comprises an upper nozzle cover (1051) fitted with the upper cone (1031) and a lower nozzle cover (1052) fitted with the blocking body (1033).

5. The anti-flashback burner nozzle according to claim 1, characterized in that: The diameters of the plurality of spray holes (102) gradually increase in the upward direction.

6. The anti-flashback burner nozzle according to claim 1, characterized in that: A threaded ring (106) is provided below the adjustment channel (101).

7. The anti-flashback burner nozzle according to claim 1, characterized in that: A plurality of layers of fire-retardant metal plates (201) and a large threaded ring (202) located above the conveying channel (2) are arranged in the conveying channel (2).

8. The anti-flashback burner nozzle according to claim 7, characterized in that: The fire-blocking metal plate (201) comprises multiple layers of fire-blocking units, each of which is a coaxially arranged cylinder with a corrugated structure, and a narrow channel is arranged between each layer of fire-blocking units.

9. A burner comprising the anti-flashback burner nozzle according to claim 1.

10. The operating method of the anti-flashback burner nozzle according to claim 1, characterized in that: The following steps are involved: (S1) the exhaust gas enters the conveying channel (2), passes through several layers of fire-retardant metal plates (201), and then enters the regulating channel (101). Under the action of pressure, the regulating mechanism (103) gradually separates from the supporting mechanism (104), rises along the regulating channel (101), and gradually passes over several spray holes (102) located on the side wall of the regulating channel (101). The opened spray holes (102) begin to discharge gas and release pressure. When the flow rate and the pressure release rate are stable, the regulating mechanism (103) begins to stabilize. (S2) When the pressure continues to rise, the regulating mechanism (103) will continue to rise to open the blocked spray hole (102), and when the flow rate and the pressure release rate are stable, a stable state is reached again; (S3) When the pressure continues to increase, the regulating mechanism (103) rises to the top of the nozzle (105), and all the nozzle holes (102) spray the exhaust gas, which is ignited by the fuel gas of the combustion furnace.

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