CN113531524A

CN113531524A - Flue gas self-circulation low-nitrogen combustion head

Info

Publication number: CN113531524A
Application number: CN202010279233.5A
Authority: CN
Inventors: 蔡晓旭
Original assignee: Tibet Huitong New Energy Co ltd
Current assignee: Tibet Huitong New Energy Co ltd
Priority date: 2020-04-10
Filing date: 2020-04-10
Publication date: 2021-10-22

Abstract

The invention discloses a flue gas self-circulation low-nitrogen combustion head which comprises an outer cylinder body, wherein a fuel injection device is arranged in the outer cylinder body, a port of the outer cylinder body is connected with a contraction injection cover, the contraction injection cover is outwards extended, an opening is contracted towards the direction of a central axis, a flue gas backflow cover is sleeved outside the outer cylinder body and the contraction injection cover, and a ventilation support is supported between the flue gas backflow cover and the outer cylinder body or the contraction injection cover. This burning head combines together with burner, wears to establish and uses on the boiler lateral wall, and the flue gas in the boiler forms the circulation at the oral area of burning head when can burning, reduces nitrogen oxide and discharges, need not extra investment moreover almost, excellent in use effect, facilitate promotion.

Description

Flue gas self-circulation low-nitrogen combustion head

Technical Field

The invention relates to a combustion device, in particular to a flue gas self-circulation low-nitrogen combustion head.

Background

In recent years, the economic growth of China is rapid, the energy consumption is remarkably improved, and the problem of environmental pollution caused by the energy consumption is increasingly severe. At present, the environmental protection department in China has higher and higher requirements on the emission limit of pollutants generated by combustion, and the NOx emission standard of boilers is improved to be less than 30mg/m for carrying out heavy year. For this reason, reducing NOx emissions is one of the primary goals of various current combustion device designs.

Currently, the main technology for controlling NOx emissions of gas burnersThe means comprises air classification, air rotational flow and direct current wind matching, gas classification, flue gas recirculation and other modes. Air staging and gas staging are limited by the size of existing burner installations, as well as by gas and air pressure, and contribute to a limited degree of NOx emission reduction, and furthermore, do not have corresponding liquid-fueled ultra-low nitrogen burners. Therefore, the flue gas recirculation method is widely applied to the gas boiler at present. In the traditional flue gas recirculation, a hole is formed in the rear of a boiler induced draft fan, and a return fan is additionally arranged to pump out flue gas generated by combustion and mix the flue gas with air, and then the flue gas is sent into a combustor. The circulating flue gas contains a large amount of CO₂And N₂After being mixed with air, the mixed gas dilutes the oxygen concentration on one hand, and improves the cold air amount on the other hand under the condition of not increasing the oxygen concentration, thereby being beneficial to reducing the flame temperature and prolonging the combustion reaction time, thereby avoiding the local high temperature of a hearth and effectively inhibiting the generation of NOx. The use of flue gas recirculation can reduce NOx emissions by 60-80%. However, the traditional flue gas recirculation mode needs to rearrange a circulating flue gas pipeline, and a circulating fan is purchased, so that the investment is increased, new requirements are provided for operation management, and the flue gas recirculation mode is inconvenient to popularize and use.

Disclosure of Invention

The invention aims to provide a flue gas self-circulation low-nitrogen combustion head, which is combined with a combustion device and is arranged on the side wall of a boiler in a penetrating way for use, so that flue gas in the boiler can form circulation at the opening part of the combustion head during combustion, the flue gas generated by burning can be automatically mixed into low-temperature air, the temperature of the flue gas is reduced, the oxygen concentration in the air is diluted, the emission of nitrogen oxides is reduced, almost no additional investment is needed, the use effect is good, and the popularization is convenient.

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

the utility model provides a flue gas self-loopa low nitrogen combustion head, includes outer barrel, is equipped with fuel injection apparatus in outer barrel, and the port of outer barrel even has the shrink to spray the cover, and the shrink sprays the cover and outwards extends and the opening is to the direction shrink of central axis, and it has flue gas backward flow cover to spray the cover overcoat at outer barrel and shrink, at flue gas backward flow cover with it has the ventilation support to support between outer barrel or the shrink injection cover, fuel injection apparatus spun flame sprays the opening blowout of cover through the shrink to drive gaseous direction from outer barrel to shrink injection cover and flow through the ventilation support.

Preferably, the outer cylinder penetrates through the side wall of the boiler in a sealing manner and extends into the hearth, the ventilation support is positioned in the hearth and has a gap with the inner wall of the hearth, and when the flame is sprayed out through the opening of the shrinkage spraying cover, the flue gas in the hearth is driven to flow out through the ventilation support through the gap.

Preferably, the flue gas backflow hood is slidably supported on the ventilation support, the flue gas backflow hood is connected with a pull rod, the pull rod penetrates through the inner wall of the hearth and is exposed outside the boiler, and the pull rod is pulled to adjust a gap between the ventilation support and the inner wall of the hearth.

Preferably, the fuel injection device comprises an inner cylinder, the inner cylinder is connected with the fan, a plurality of peripheral gas spray guns are arranged between the inner cylinder and the outer cylinder, a central gas spray gun is arranged in the inner cylinder, and a hydrogen water vapor spray gun is further arranged in the central gas spray gun.

Preferably, the end part of the outer cylinder is hermetically connected to the inner cylinder, the outer cylinder is provided with an outer air inlet, the inner cylinder is provided with an inner air inlet, the inner air inlet is provided with a movable baffle, and the outer side of the outlet of the central gas spray gun is provided with an air swirler.

Preferably, the fuel injection device comprises an inner cylinder, the inner cylinder is connected with the fan, a central fuel spray gun is arranged in the inner cylinder, the central fuel spray gun is connected with the fuel supply pipe, and the central fuel spray gun is also connected with a hydrogen steam pipeline.

Preferably, the end part of the outer cylinder is hermetically connected to the inner cylinder, the outer cylinder is provided with an outer air inlet, the inner cylinder is provided with an inner air inlet, the inner air inlet is provided with a movable baffle, and the outer side of the outlet of the central fuel spray gun is provided with an air swirler.

Preferably, the fuel injection device comprises an inner cylinder, the inner cylinder is connected with the biomass burner, biomass is combusted in the biomass burner, flame is sprayed out from the opening of the inner cylinder, and then the flame is sprayed out through the contraction spraying cover.

Preferably, the biomass burner comprises a combustion chamber, a fuel adding port is arranged above the combustion chamber, one side of the combustion chamber is communicated with the inner cylinder, the combustion chamber is also provided with a hot air inlet and a combustion-supporting gas inlet, and the lower part of the combustion chamber is connected with an ash falling chamber through a fire grate.

In the technical scheme of the invention, the combustion device can be used for burning gas, fuel oil or biomass, the fuel gas sprays fuel to the opening part of the inner cylinder through the central gas spray gun, the outer gas spray gun and the hydrogen water vapor spray gun of the fuel injection device, air is fed from the channel between the outer cylinder and the inner cylinder, the burning flame is contracted and sprayed out at an accelerated speed through the contraction injection cover, at the moment, the material at the opening part is driven to rapidly flow and generate negative pressure at the opening part, the negative pressure enables the gas around the smoke backflow cover to flow into a negative pressure zone, the effect that the smoke flows through the ventilation support from the gap to move to the opening part of the contraction injection cover is formed by combining the arrangement of the ventilation support and the gap existing between the ventilation support and the inner wall of the hearth, the cold air flowing from the channel between the inner cylinder and the outer cylinder is mixed in the process, so that the cold air cools the smoke dilutes the concentration of oxygen in the cold air, the combustion is prevented from generating overhigh temperature, thereby effectively inhibiting the generation of nitrogen oxides. The realization of above-mentioned effect only can realize through flue gas backward flow cover, ventilation support, shrink injection cover and their position relation each other and with the position relation of furnace inner wall, does not need solitary draught fan, singly establish pipeline passageway etc. does not basically increase equipment cost, does not also need independent electric drive, has effectively reduced on the basis of hardly increasing the cost again and has discharged when the oxide, has promoted combustion effect. The fuel spray gun and the biomass fuel have similar effects. The hydrogen vapor and the fuel gas are mixed, or the hydrogen vapor is introduced into a fuel pipeline to atomize fuel, or is introduced into a biomass combustion device, so that the effects of combustion assistance, tar-free generation and nitrogen oxide emission are reduced, and the energy conservation and environmental protection of combustion are better promoted before the effects. .

Drawings

FIG. 1 is a schematic view of the present invention (using gas as fuel);

FIG. 2 is a sectional view taken along A-A of FIG. 1

FIG. 3 is another schematic view of the present invention (with fuel oil as fuel);

FIG. 4 is a cross-sectional view taken along AA of FIG. 3;

FIG. 5 is a schematic structural view (using biomass as fuel) of a third embodiment of the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings:

as shown in fig. 1 to 5, the flue gas self-circulation low-nitrogen combustion head provided by the invention comprises an outer cylinder 3, and a fuel injection device is arranged in the outer cylinder 3 and used for injecting flame generated by combustion of fuel gas, fuel oil or biomass outwards. The port of outer barrel 3 is connected with the shrink and sprays cover 10, and shrink sprays cover 10 one end and outer barrel 3's opening seal and links to each other, and the other end outwards extends and constantly contracts, forms an opening 1001 that the diameter is less than outer barrel 3, and when the flame blowout that forms like this passed opening 1001, will produce faster velocity of movement, produced the injection effect. The outer barrel 3 is externally sleeved with a smoke backflow cover 1 which is cylindrical, the diameter of the smoke backflow cover is larger than that of the outer barrel 3, and a circle of ventilation support 2 can be arranged outside the outer barrel 3 and used for supporting the outer barrel 3. In one embodiment, the ventilation bracket 2 is a fan-shaped annular grid, one end of the ventilation bracket is fixedly connected outside the outer cylinder 3, the other end of the ventilation bracket supports the inner wall of the flue gas backflow cover 1, and the flue gas backflow cover 1 can slide along the ventilation bracket 2. The ventilation support may also be a device through which gas can pass and which supports the fume hood. A flue gas return channel 15 is formed between the flue gas return hood 1 and the contraction injection hood 10. When flame is sprayed out from the opening 1001, the area near the opening can generate negative pressure relative to the surrounding adjacent area because of the quick flow of gas, then the gas around the outer cylinder can move to the opening 1001 through the ventilation bracket 2 via the smoke backflow channel 15, and the side wall of the smoke backflow cover 1 has a blocking effect on the gas, so that the gas around the smoke backflow cover 1 can only flow to the opening 1001 by bypassing the ventilation bracket, and the gas generates a swirling effect.

In use, a hole is punched in the side wall 6 of the boiler, the outer cylinder 3 is inserted into the hole from the outer side and extends into the hearth, and then the outer cylinder and the edge of the hole are sealed by the filler 5. Ventilation support 2 is located furnace to have clearance 20 with the furnace inner wall, slip flue gas backward flow cover 1, can adjust the size of clearance 20, for the ease of operation, set up pull rod 4 on the flue gas backward flow cover 2, the pull rod is worn out the boiler lateral wall, pulls the pull rod outside the boiler like this, can adjust the clearance size. After flaming, flue gas in the boiler flows through the ventilation bracket 2 through the gap 20 and moves towards the opening 1001, and backflow of the flue gas is formed. The flue gas flows back to near opening 1001, mixes with the flame that burns, also helps the air that burns in the flame that burns (because fuel and cold air mix just begin to burn at the opening part, the temperature is lower relatively), so not only help cold air to reduce the temperature of flue gas, also help the concentration of oxygen in the flue gas dilution air, help the cooling to abundant burning area, avoid the production of a large amount of nitrogen oxides, produce low nitrogen combustion effect (flue gas direction of motion is as shown by two arrow about two on the rightmost side of fig. 1).

In one embodiment of the present invention, the fuel injection device in the outer cylinder 3 takes the following configuration: the flame-retardant gas burner comprises an inner cylinder 18, wherein a plurality of peripheral gas spray guns 7 are arranged between the outer cylinder 3 and the inner cylinder 18 at intervals in a circumferential manner, a central gas spray gun 8 is arranged on the central axis of the inner cylinder 18, and the peripheral gas spray guns 7 and the central gas spray gun 18 are used for spraying gas outwards and are ignited at the mouth part to form flame. The inner cylinder 10 is connected to a blower (not shown) for blowing combustion air from the inner cylinder. In order to enhance the air supply effect, an outer air inlet is formed in the outer cylinder 3, an inner air inlet 14 is formed in the inner cylinder, and air can enter the inner cylinder from the outer air inlet and the inner air inlet 14 to support combustion (two groups of arrows on the left side in fig. 1 represent the air flow direction). An adjustable wind shield 17 can be arranged on the inner air inlet 14, and the wind shield 17 is connected with the rest adjusting rods 12 for adjusting the air inlet amount.

As a preferred embodiment, a hydrogen steam spray gun 9 is further arranged in the central gas spray gun 8 and used for introducing hydrogen steam mixed gas, so that combustion supporting is facilitated, the tar content can be reduced, the generation of nitrogen oxides is further reduced, and the environment-friendly and combustion effects are improved. The air swirler 11 can be arranged outside the central gas spray gun, the air swirler 11 can enable air flow sprayed out of the inner cylinder body to form swirl air, namely the swirl air of the central air is obtained, so that the stability of central flame is improved, the mixing effect of air and gas is enhanced, and the length of the flame is shortened. The peripheral gas spray gun 7 and the central gas spray gun 8 are connected with a gas header 13, and the hydrogen vapor spray gun 9 is connected with a hydrogen vapor preparation device.

In the above scheme, the specific size of the flue gas reflux cover 1 can be determined by a method for calculating fluid according to the actual requirements and the sizes of the outer cylinder and the inner cylinder and the gas quantity by a person skilled in the art. Generally, the adjustment range of the circulating flue gas amount is 0-20% of the air amount required by combustion.

In another embodiment, the fuel injection device in the outer cylinder 3 takes the following configuration: the fuel burner comprises an inner cylinder 18, a central fuel spray gun 30 is arranged on the central axis of the inner cylinder 18, the central fuel spray gun 30 is connected with a fuel pipeline 31 and a hydrogen steam pipeline 32, after hydrogen steam enters the central fuel spray gun 30, fuel is atomized, sprayed out from the outlet of the central fuel spray gun 30 and ignited, and flame is sprayed out through a contraction emission cover 10. The flue gas forms the circulation through ventilation support 2, flue gas return passage 15, mixes the back with the gas, can reduce the flue gas temperature, also can dilute oxygen concentration, reduces the production of nitrogen oxide. The inner cylinder 10 is connected to a blower (not shown) for blowing combustion air from the inner cylinder. In order to enhance the air supply effect, an outer air inlet is formed in the outer cylinder 3, an inner air inlet 14 is formed in the inner cylinder, and air can enter the inner cylinder from the outer air inlet and the inner air inlet 14 to support combustion (two groups of arrows on the left side in fig. 3 represent the air flow direction). An adjustable wind shield 17 can be arranged on the inner air inlet 14, and the wind shield 17 is connected with the rest adjusting rods 12 for adjusting the air inlet amount. The air swirler 11 can be arranged outside the central gas spray gun, the air swirler 11 can enable air flow sprayed out of the inner cylinder body to form swirl air, namely the swirl air of the central air is obtained, so that the stability of central flame is improved, the mixing effect of air and gas is enhanced, and the length of the flame is shortened. In the case of gas and fuel, an ignition needle may be provided near the outlet of the inner cylinder for ignition.

In another embodiment, the fuel injection device in the outer cylinder 3 takes the following configuration: the fuel injection device comprises an inner cylinder 18, the inner cylinder 18 is connected with the biomass burner 7, biomass is combusted in the biomass burner 7, flame is sprayed out from the opening of the inner cylinder, and then the flame is sprayed out through the contraction spray cover. The biomass burner comprises a combustion chamber 71, a fuel adding port 72 is arranged above the combustion chamber, one side of the combustion chamber 71 is communicated with the inner cylinder 18, the combustion chamber 71 is also provided with a hot air inlet 74 and a combustion-supporting gas inlet 75, and the lower part of the combustion chamber 71 is connected with an ash falling chamber 77 through a fire grate 76. Biomass raw materials such as coal, straws and the like are placed into a combustion chamber 71 through a fuel adding port 72 and ignited, hot air enters from a hot air inlet 74, hydrogen steam enters into the combustion chamber from a combustion-supporting gas inlet 75 to help combustion, flame enters into a boiler hearth from an inner cylinder and is sprayed out from a contraction spraying cover 10, smoke can be circulated, and emission of nitrogen oxides is reduced.

The above embodiments are merely illustrative of the concept and implementation of the present invention, and are not restrictive, and technical solutions that are not substantially changed under the concept of the present invention are still within the scope of protection.

Claims

1. The utility model provides a flue gas self-loopa low-nitrogen combustion head, includes outer barrel, its characterized in that is equipped with fuel injection apparatus in outer barrel, and the port of outer barrel even has the shrink to spray the cover, and the shrink sprays the cover and outwards extends and the opening is to the direction shrink of central axis, has flue gas backward flow cover at outer barrel and shrink injection cover overcoat, at flue gas backward flow cover with it has the ventilation support to support between outer barrel or the shrink injection cover, fuel injection apparatus spun flame sprays through the opening blowout of shrink injection cover to drive gas to flow through to the direction of shrink injection cover from outer barrel the ventilation support.

2. The flue gas self-circulation low-nitrogen combustion head as claimed in claim 1, wherein the outer cylinder is sealed and extends into the furnace through the side wall of the boiler, the ventilation bracket is positioned in the furnace and has a gap with the inner wall of the furnace, and when the flame is ejected through the opening of the contraction jet cover, the flue gas in the furnace is driven to flow out through the ventilation bracket from the gap.

3. The flue gas self-circulation low-nitrogen combustion head as claimed in claim 1, wherein the flue gas return hood is slidably supported on the ventilation bracket, the flue gas return hood is connected with a pull rod, the pull rod penetrates through the inner wall of the furnace and is exposed outside the boiler, and the gap between the ventilation bracket and the inner wall of the furnace can be adjusted by pulling the pull rod.

4. The flue gas self-circulation low-nitrogen combustion head as claimed in claim 1, 2 or 3, wherein the fuel injection device comprises an inner cylinder, the inner cylinder is connected with a fan, a plurality of peripheral gas injection guns are arranged between the inner cylinder and the outer cylinder, a central gas injection gun is arranged in the inner cylinder, and a hydrogen water vapor injection gun is arranged in the central gas injection gun.

5. The flue gas self-circulation low-nitrogen combustion head as claimed in claim 4, wherein the end of the outer cylinder is hermetically connected to the inner cylinder, the outer cylinder is provided with an outer air inlet, the inner cylinder is provided with an inner air inlet, the inner air inlet is provided with a movable baffle, and the outer side of the outlet of the central gas spray gun is provided with an air swirler.

6. The flue gas self-circulation low-nitrogen burner head as claimed in claim 1, 2 or 3, wherein the fuel injection device comprises an inner cylinder connected to the blower, and a central fuel injection lance is provided in the inner cylinder and connected to the fuel supply pipe, and the central fuel injection lance is further connected to the hydrogen steam line.

7. The flue gas self-circulation low-nitrogen combustion head as claimed in claim 6, wherein the end of the outer cylinder is hermetically connected to the inner cylinder, the outer cylinder is provided with an outer air inlet, the inner cylinder is provided with an inner air inlet, the inner air inlet is provided with a movable baffle, and the outer side of the outlet of the central fuel spray gun is provided with an air swirler.

8. The flue gas self-circulation low-nitrogen combustion head as claimed in claim 1, 2 or 3, wherein the fuel injection device comprises an inner cylinder, the inner cylinder is connected with a biomass burner, biomass is combusted in the biomass burner, flame is sprayed out from the opening of the inner cylinder, and then is sprayed out through the contraction spray cover.

9. The flue gas self-circulation low-nitrogen combustion head as claimed in claim 8, wherein the biomass burner comprises a combustion chamber, a fuel adding port is arranged above the combustion chamber, one side of the combustion chamber is communicated with the inner cylinder, the combustion chamber is further provided with a hot air inlet and a combustion-supporting air inlet, and the lower part of the combustion chamber is connected with an ash falling chamber through a fire grate.