CN110925756A

CN110925756A - Dilute phase premixing burner

Info

Publication number: CN110925756A
Application number: CN201911305721.2A
Authority: CN
Inventors: 单忠民; 范洪波; 邓李刚
Original assignee: Luoyang Xinpu Petrochemical Equipment Development Co Ltd
Current assignee: Luoyang Xinpu Petrochemical Equipment Development Co Ltd
Priority date: 2019-12-18
Filing date: 2019-12-18
Publication date: 2020-03-27

Abstract

A dilute-phase premixing burner relates to a burner, which comprises a shell, a flame path brick, an on-duty nozzle and two sections of gas spray guns, wherein the shell is fixed at the bottom of a heating furnace through a connecting flange; the invention has simple structure and good combustion effect, and the first section of the gas spray gun adopts small spray hole diameter and large spray angle to strengthen the mixing of gas and air to eliminate carbon precipitation and avoid the backfire under low-load working condition, thereby improving combustion adjusting efficiency.

Description

Dilute phase premixing burner

Technical Field

The invention relates to a combustor, in particular to a dilute-phase premixing combustor.

Background

As is known, in the petrochemical industry, an industrial furnace using gas as an energy source ignites introduced gas through a burner and then converts the ignited gas into required heat energy, but a burner of a heating furnace generates a large amount of NOx emission when in operation, while NOx is a pollutant harmful to human health and atmospheric environment, countries in the world have or are making stricter standards to control the emission of NOx, as the environmental requirements are higher and higher, the emission concentration limit value of NOx is gradually reduced, and in order to reduce the emission amount of NOx, the most important measures adopted for improving combustion equipment are a staged combustion technology and a flue gas internal recirculation technology; conventional staged combustion techniques, which lower the flame temperature by keeping the combustion reaction of fuel and air away from its stoichiometric ratio; the flue gas recirculation is to realize external recirculation through an external mechanism or realize internal recirculation by utilizing a fluid internal mechanism, so that flue gas in a furnace at a relatively low temperature is introduced into flame, and the flame temperature is reduced; the idea of lowering flame temperature in conventional low NOx burners is to actually weaken the combustion, which causes a series of side effects: the weakening of gas combustion can increase incomplete combustion loss, cause insufficient combustion, secondary combustion in a convection section of the furnace and increase the content of CO in smoke exhaust; therefore, it is a basic demand of those skilled in the art to provide a lean premixed burner that can reduce NOx emissions to a level far below a predetermined level.

Disclosure of Invention

In order to overcome the defects in the background art, the invention discloses a dilute phase premix burner.

In order to realize the purpose, the invention adopts the following technical scheme:

a dilute phase premixing burner comprises a shell, a flame path brick, an on-duty nozzle and two sections of gas spray guns, wherein the shell is fixed at the bottom of a heating furnace through a connecting flange, the shell is uniformly provided with the two sections of gas spray guns fixed through the flange along the circumferential direction, the two sections of gas spray guns are all communicated with a gas collection chamber outside the shell through gas pipes, the upper part of the shell is provided with the flame path brick, a premixing component is arranged in the shell, the on-duty nozzle is arranged between the shell and the premixing component, the on-duty nozzle and the upper part of the premixing component are both arranged in a central hole of the flame path brick and are fixed through the flange, the premixing component comprises an inner cylinder, a flame bowl brick, a flame brick support and one section of gas spray gun, the inner cylinder is fixed on the inner surface of the shell through a plurality of rib plates, the front part inside the inner cylinder is fixed with the flame brick support, the lower, the front end of one section gas spray gun sets up in the centre bore that the firebrick held in the palm, and corresponding with the firebrick, the lower extreme of inner tube and the panel fixed connection of casing lower part, the lower extreme setting of one section gas spray gun is outside at the casing, be equipped with the primary air door that communicates with the inner tube in one side of casing, one section gas spray gun includes shower nozzle and honeycomb duct, the honeycomb duct passes through mounting flange to be fixed on the rear end face of collection chamber, the shower nozzle is installed to the front end of honeycomb duct, the rear end of honeycomb duct is equipped with gas entry.

The dilute phase premixing burner is characterized in that a gas collection chamber is arranged outside a lower panel of the shell, and the lower end of the first section of gas spray gun penetrates through the gas collection chamber and is arranged outside the gas collection chamber.

The dilute phase premixing burner has the advantages that the fire pan brick is of a hollow structure and is composed of an upper fire pan brick and a lower fire pan brick, the upper fire pan brick is internally provided with a porous cyclone, an inner hole mixing chamber of the lower fire pan brick is of a Venturi structure, the lower part of the upper fire pan brick is provided with a boss, and the boss is connected with a concave table at the upper end part of the lower fire pan brick.

The dilute phase premixing burner is characterized in that an air adjusting handle is arranged on a primary air door.

In the dilute-phase premixing burner, the power load ratio of the first-stage gas spray gun and the second-stage gas spray gun is 1:20, and the output power of the burner is adjusted according to the load requirement of a furnace by adjusting the power load.

The nozzle of the dilute phase premix burner is made of heat-resistant alloy steel 06Cr25Ni 20.

The on-duty ratio of the on-duty nozzle, namely the percentage of the on-duty fuel quantity to the total fuel quantity, of the lean-phase premixed burner is controlled to be less than 15%, and the cross sections of the spray holes of the on-duty nozzle and the section of the gas spray gun are determined by the on-duty ratio.

Due to the adoption of the technical scheme, the invention has the following beneficial effects:

1. according to the dilute-phase premix burner, the first-stage gas spray gun and the second-stage gas spray gun are arranged, the power load of the first-stage gas spray gun is small, the power load of the second-stage gas spray gun is large, a thermal force field can be formed due to load difference when the two-stage spray guns perform synergistic combustion, the entrainment smoke quantity can be increased, the concentration of fuel gas is diluted by mixing of smoke, the combustion reaction speed can be reduced, and the flame peak temperature is reduced; the effect of reducing the flame temperature is also achieved by absorbing heat from the mixed flue gas, and the higher the mixed flue gas amount and the lower the flue gas temperature, the higher the ignition temperature becomes, which is more beneficial for reducing the flame temperature and reducing the generation of NOx.

2. According to the dilute-phase premixing burner, the upper fire pan brick adopts the radial porous swirler as a flame stabilizer, the inner hole of the lower fire pan brick is of a Venturi structure, the introduction rate of combustion air can be increased, a part of air is used as an air blending gas and enters a mixing chamber through a blending channel from a primary air door, the air and fuel are mixed in the mixing chamber to realize full premixing in a premixing section, and then the air and the fuel enter the fire pan for combustion. A small part of the entrainment smoke is used as cooling gas of a local area of the flame, and the rest air flows out to the swirler in the radial direction so as to reduce the peak temperature of the flame.

3. The primary air door is independently used as a channel for supplying combustion air for the first-stage gas spray gun, and the opening degree of a disc in the air door is adjusted through the air adjusting handle so as to adjust the inflow of the air; combustion-supporting air enters from the primary air channel, flows through the inner barrel and is mixed with fuel gas sprayed by the section of fuel gas spray gun in the fire pan brick mixing chamber to be combusted, a large amount of excess air is mixed into the mixed gas, so that the fuel concentration is in a combustible range and becomes as thin as possible, and at the moment, the excess air absorbs heat released by partial combustion and exceeds the air required by combustion to absorb heat to reduce the flame temperature, so that the flame temperature is reduced to be very low, and the generated NOx amount is less than that of diffusion combustion.

4. The invention has simple structure and good combustion effect, and the first section of the gas spray gun adopts small spray hole diameter and large spray angle to strengthen the mixing of gas and air to eliminate carbon precipitation and avoid the backfire under low-load working condition, thereby improving combustion adjusting efficiency;

5. according to the dilute-phase premixing burner, a set of premixed combustion type spray gun is added on the basis of a two-section spray gun to serve as a one-section spray gun, and the flames of two-section thick and thin combustion have a subsequent combustion reaction of opposed combustion, so that complete combustion is realized, and the phenomena of secondary combustion and increase of CO content in smoke exhaust in a convection section of a furnace due to weakened combustion of a traditional burner can be avoided.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a top view of the present invention;

FIG. 3 is a schematic view of the construction of the premix member of the present invention;

FIG. 4 is a schematic structural view of the upper firebrick of the present invention;

FIG. 5 is a top plan view of the upper firebrick of the present invention;

FIG. 6 is a schematic view of the construction of the lower firebrick of the present invention;

FIG. 7 is a schematic view of a segment of the gas lance of the present invention;

in the figure: 1. a flame path brick; 2. a nozzle on duty; 3. a secondary air door; 4. a premix member; 5. a housing; 6. a second section of gas spray gun; 7. a fire pan brick; 8. a rib plate; 9. a porous cyclone; 10. a primary air door; 11. a wind adjusting handle; 12. a segment of gas spray gun; 13. an inner barrel; 14. fire-supporting bricks; 15. an upper firebrick; 16. a boss; 17. a concave platform; 18. an inner bore; 19. a lower fire pan brick; 20. a spray head; 21. a flow guide pipe; 22. installing a flange; 23. a gas inlet bulb; 24. and (5) collecting the gas.

Detailed Description

The present invention will be explained in detail by the following examples, which are disclosed for the purpose of protecting all technical improvements within the scope of the present invention.

The dilute phase premixing burner described by combining the attached drawings 1-7 comprises a shell 5, a flue brick 1, an on-duty nozzle 2 and two sections of gas spray guns 6, wherein the shell 5 is fixed in a heating furnace body through a connecting flange, a plurality of two sections of gas spray guns 6 fixed through flanges are uniformly distributed on the shell 5 along the circumferential direction, the plurality of two sections of gas spray guns 6 are communicated with a gas collection chamber 24 outside the shell 5 through gas pipes, the flue brick 1 is arranged on the upper part of the shell 5, a premixing component 4 is arranged in the shell 5, the on-duty nozzle 2 is arranged between the shell 5 and the premixing component 4, the on-duty nozzle 2 and the upper part of the premixing component 4 are both arranged in a central hole of the flue brick 1 and are fixed through flanges, the premixing component 4 comprises an inner cylinder 13, a fire basin brick 7, a fire brick support 14 and a section of gas spray gun 12, the inner cylinder 13 is fixed on the inner surface of the shell 5 through a plurality of rib plates 8, the lower part of firebrick 7 is fixed on firebrick holds in the palm 14, inner tube 13 center department is equipped with one section gas spray gun 12, the front end setting of one section gas spray gun 12 is in the centre bore that firebrick held in the palm 14, and corresponding with firebrick 7, the lower extreme of inner tube 13 and the panel fixed connection of 5 lower parts of casing, the lower extreme setting of one section gas spray gun 12 is outside at casing 5, one side at casing 5 is equipped with the primary air door 10 with the inner tube intercommunication, one section gas spray gun 12 includes shower nozzle 20 and honeycomb duct 21, honeycomb duct 21 passes through mounting flange 22 to be fixed on the rear end face of collection chamber 24, shower nozzle 20 is installed to honeycomb duct 21's front end, honeycomb duct 21's rear end.

In the dilute phase premix burner, a gas collection chamber 24 is arranged outside the lower panel of the shell 5, and the lower end of the first-stage gas spray gun 12 passes through the gas collection chamber 24 and is arranged outside the gas collection chamber 24.

Dilute phase premix combustor, fire basin brick 7 are hollow structure, constitute by upper portion fire basin brick 15 and lower part fire basin brick 19, are equipped with porous swirler 9 in the upper portion fire basin brick 15, the hole 18 mixing chamber of lower part fire basin brick 19 is the venturi structure, the lower part of upper portion fire basin brick 15 is equipped with boss 16, and is connected with the concave station 17 of lower part fire basin brick 19 upper end.

The dilute phase premixing burner is characterized in that an air adjusting handle 11 is arranged on a primary air door 10.

In the dilute-phase premixing burner, the power load ratio of the first-stage gas spray gun 12 and the second-stage gas spray gun 6 is 1:20, and the output power of the burner is adjusted according to the load requirement of a furnace by adjusting the power load.

In the dilute phase premix burner, the nozzle 20 is made of heat-resistant alloy steel 06Cr25Ni 20.

The on-duty ratio of the on-duty nozzle 2 of the dilute-phase premixed burner, namely the percentage of the on-duty fuel quantity to the total fuel quantity, is controlled to be less than 15%, and the cross sections of the spray holes of the on-duty nozzle 2 and the section of the gas spray gun 12 are determined by the on-duty ratio.

When the dilute-phase premix burner is used, the primary air door 10 is independently used as a channel for supplying combustion air to the first-stage gas spray gun 12, the opening degree of a disc inside the air door is adjusted through the air adjusting handle 11 to adjust the inflow of air, combustion-supporting air enters from a primary air channel of the primary air door 10, and is mixed with gas sprayed out of the first section of gas spray gun 12 after flowing through the inner cylinder 13 and then is combusted in a mixing chamber of a lower fire basin brick 19, the mixing chamber of the lower fire basin brick 19 is of a Venturi structure, the introduction rate of combustion air can be enhanced, a part of air as the mixed gas enters the mixing chamber from the primary air door 10, the air and the fuel are mixed in the mixing chamber to realize the full premixing in the premixing section, then the flue gas enters a fire pan for combustion, a small part of the entrainment flue gas is used as cooling gas of a local area of a section of flame, and the rest air flows out radially to the porous swirler 9 so as to reduce the peak temperature of the flame; the first section of the gas spray gun 12 adopts a small spray hole diameter and a large spray angle to strengthen the mixing of gas and air to eliminate carbon precipitation and avoid the tempering under the low-load working condition, thereby improving the combustion regulation efficiency; the two-stage gas spray gun 6 is set into six groups of twelve gas spray guns, which are respectively communicated with the gas collection chamber 24 through six gas pipelines, the nozzle of the two-stage gas spray gun 6 faces the direction of the flue brick 1, the power load ratio of the first-stage gas spray gun 12 to the second-stage gas spray gun 6 is 1:20, and a thermal force field is formed by the two-stage gas spray guns due to load difference during collaborative combustion, so that the entrainment smoke gas quantity is improved, the gas concentration is diluted by the mixed smoke gas, the combustion reaction speed is reduced, and the flame peak temperature is reduced; and the flame temperature can be reduced by absorbing heat of the mixed flue gas, and the higher the mixed flue gas quantity is, the lower the flue gas temperature is, the higher the ignition temperature becomes, so that the flame temperature is reduced, and the NOx generation is reduced.

The present invention is not described in detail in the prior art.

The embodiments selected for the purpose of disclosing the invention, are presently considered to be suitable, it being understood, however, that the invention is intended to cover all variations and modifications of the embodiments which fall within the spirit and scope of the invention.

Claims

1. The dilute phase premixing burner comprises a shell, a flame path brick, an on-duty nozzle and a two-section gas spray gun, and is characterized in that: the shell is fixed at the bottom of the heating furnace through a connecting flange, a plurality of two-section gas spray guns fixed through the flange are uniformly distributed on the shell along the circumferential direction, the two-section gas spray guns are all communicated with a gas collection chamber outside the shell through gas pipes, a flame path brick is arranged at the upper part of the shell, a premixing component is arranged in the shell, an on-duty nozzle is arranged between the shell and the premixing component, the on-duty nozzle and the upper part of the premixing component are both arranged in a central hole of the flame path brick and are all fixed through the flange, the premixing component comprises an inner cylinder, a flame pan brick, a flame brick support and a section of gas spray gun, the inner cylinder is fixed on the inner surface of the shell through a plurality of rib plates, the front part inside the inner cylinder is fixed with the flame brick support, the lower part of the flame pan brick support is fixed on the upper surface of the flame brick support, the center of the inner, the lower extreme of inner tube and the panel fixed connection of casing lower part, the lower extreme setting of one section gas spray gun is outside at the casing, is equipped with the primary air door with the inner tube intercommunication in one side of casing, and one section gas spray gun includes shower nozzle and honeycomb duct, and the honeycomb duct passes through mounting flange to be fixed on the rear end face of collection chamber, and the shower nozzle is installed to the front end of honeycomb duct, and the rear end of honeycomb duct is equipped with the gas entry bulb.

2. The lean phase premix burner as in claim 1, wherein: the outside of the lower panel of the shell is provided with a gas collection chamber, and the lower end of the first section of gas spray gun passes through the gas collection chamber and is arranged outside the gas collection chamber.

3. The lean phase premix burner as in claim 1, wherein: the fire pan brick is hollow structure, comprises upper portion fire pan brick and lower part fire pan brick, is equipped with porous swirler in the upper portion fire pan brick, and the hole mixing chamber of lower part fire pan brick is venturi structure, and the lower part of upper portion fire pan brick is equipped with the boss, and is connected with the concave station of lower part fire pan brick upper end.

4. The lean phase premix burner as in claim 1, wherein: an air adjusting handle is arranged on the primary air door.

5. The lean phase premix burner as in claim 1, wherein: the power load ratio of the first-stage gas spray gun to the second-stage gas spray gun is 1:20, and the output power of the combustor is adjusted according to the load requirement of the furnace through adjusting the power load.

6. The lean phase premix burner as in claim 1, wherein: the material of the nozzle is heat-resistant alloy steel 06Cr25Ni 20.

7. The lean phase premix burner as in claim 1, wherein: the duty ratio of the duty nozzle, namely the percentage of the duty fuel quantity to the total fuel quantity, is controlled to be less than 15%, and the cross sections of the spray holes of the duty nozzle and the section of the gas spray gun are determined according to the duty ratio.