CN111578279A

CN111578279A - Dimethyl ether gas boiler combustor nitrogen reduction device

Info

Publication number: CN111578279A
Application number: CN202010571775.XA
Authority: CN
Inventors: 石瑞章; 张顺平; 秦建党; 郭永军; 李贵利; 杨忠华; 李战华; 于晓亮
Original assignee: Hebi Baofa Energy Science & Technology Co ltd
Current assignee: Hebi Baofa Energy Science & Technology Co ltd
Priority date: 2020-06-22
Filing date: 2020-06-22
Publication date: 2020-08-25

Abstract

The invention discloses a dimethyl ether gas boiler burner nitrogen reduction device, which solves the technical problem that the heat efficiency of a boiler is reduced when the flame temperature is reduced for reducing nitrogen oxides generated by combustion in the prior art. The invention comprises an outer shell, wherein a cyclone mechanism is arranged in an inner cavity of the outer shell, one end of the outer shell is provided with an air suction hole opposite to the cyclone mechanism, the other end of the outer shell is provided with a fire outlet, a first fuel central spray pipe opposite to the fire outlet is arranged in the outer shell, and an outer ring fire spraying unit is arranged around the outer shell. The invention adopts a structure mode of combining the small-aperture flame spray nozzle and the flame spray hole to construct the multi-nozzle small-hole flame spray, and adopts a central flame premixing method, so that the flame temperature is reduced and the heat efficiency is not changed. The emission standard of nitrogen oxides in Beijing and Shanghai is as follows: less than 30 mg per cubic meter. Ten days of combustion tests using the burner of the present invention showed nitrogen oxide emissions below 30 mg per cubic meter, only 26 mg.

Description

Dimethyl ether gas boiler combustor nitrogen reduction device

Technical Field

The invention belongs to the technical field of burners, and particularly relates to a dimethyl ether gas boiler burner nitrogen reduction device.

Background

Dimethyl ether fuel gas is cleaner than other fuel gases, and the main pollutant of the dimethyl ether fuel gas is Nitrogen Oxide (NO)_X)，NO_XIn addition to the harm to human health, photochemical smog is generated in the atmosphere through a series of physical and chemical reactions, sunlight and hydrocarbon, ozone and the like. Not only that, NO_XMeanwhile, the method is also an important cause for forming acid rain, and is an important source for generating the atmospheric ultrafine particulate matters (PM 2.5). Nitrogen Oxides (NO)_X) Generation mechanism of (1) and NO generated in the combustion process of gas_XThe types of the fuel type, the thermal type and the rapid type are three main types. The rapid type NO_XThe high-temperature decomposition of carbon oxide in the combustion process generates CH free radical and N in the air₂HCN and N are generated through molecular reaction and generated after further oxidation, and the reaction time only needs 60 ms. Rapid NO_XThe production of (A) is relatively small, usually less than 5%. Said fuel type NO_XRefers to the production of nitrogen-containing compounds in the fuel during the combustion process. Nitrogen in nitrogen-containing compounds in fuels is generally present in atomic form, has low bond energy, and is readily decomposed during combustion for oxidation to NO_X。

Said thermal NO_XIs formed by N in the air₂Generated by oxidation at high temperature, the higher the reaction temperature, the NO_XThe faster the formation rate of (A), the thermal typeNO_XThe influencing factors of (a) are as follows:

1. NO generation at temperatures below 1300 deg.C_XVery little, NO at temperatures above 1500 ℃_XWill multiply;

2. the higher the oxygen concentration, NO_XThe greater the production;

3. the longer the residence time in the high temperature zone, the NO_XThe more production.

In the prior art, when the low-nitrogen combustion technology is improved, the thermal NO is mainly controlled_XThe direction of the control is to reduce the flame temperature, particularly the flame peak temperature, and to narrow the range of the high-temperature region of the flame, according to the generation mechanism. The specific measures are as follows: fuel/air staged combustion technology, flue gas recirculation technology (internal circulation and external circulation), full-premixing surface combustion technology, water-cooled combustion technology and low excess air coefficient method. The second type is flue gas denitration technology, which refers to the denitration of NO generated in flue gas_XThe treatment is carried out by the following main related technologies: a precious metal dedicated catalytic denitration method, a selective catalytic reduction method, a selective non-catalytic reduction method, an alkali liquor absorption method and the like.

In the boiler industry, a combustion control method is mostly adopted for a gas boiler, and the reduction of nitrogen oxides is realized mainly by optimizing the combustion process in the boiler, reasonably optimizing the mixing of fuel and air, controlling flame distribution and reducing the temperature in a hearth. The following methods are common:

air staged combustion

The air required for combustion is mixed with fuel in stages to be combusted, and the flame intensity and the flame temperature are reduced. The secondary air outlet has high air speed, and the smoke around the secondary air outlet is coiled, so that the smoke is recycled in the furnace, and the effect of grading air distribution is achieved. On the one hand, the temperature of the central flame is reduced, and on the other hand, the oxygen concentration on the surface of the flame is diluted, thereby inhibiting NO_XAnd (4) generating.

Staged combustion of fuel

The fuel staged combustion refers to feeding fuel gas into a hearth from different areas, so that the fuel is combusted stage by stage and in different areas. The space of the combustion chamber is fully utilized to disperse and arrange the fuel, thereby reducing the flame concentration and the temperature of a high-temperature area.

Staged combustion

Staged combustion is a combination of staged air combustion and staged fuel combustion, wherein air and fuel are staged to the combustion device and the ratio of fuel to air in the combustion zone is controlled. The principle of the staged combustion technology is that the lean oxygen and the peroxy are combined to disperse the flame, reduce the temperature of the flame, promote the partial circulation of the flue gas in the furnace to form a reducing atmosphere and reduce part of the generated NO into N₂Thereby controlling NO in total_XThe emission concentration of (c).

Although the staged combustion technology can reduce the generation of nitrogen oxides with certain difficulty, many burners do not completely realize the full mixing of combustion air and fuel gas in the actual use, and a local high-temperature area exists in a hearth, and the temperature of the local high-temperature area is higher than that of the furnace for producing thermal NO_XTemperature of (3) to cause NO_XThe concentration of (c) exceeds the standard. On the other hand, the existing staged combustion technology is easy to cause the phenomena of incomplete combustion such as overproof carbon monoxide, local carbon deposition and the like due to poor mixing fluidity of fuel and air. In order to reduce the reaction temperature, the flame needs to be dispersed as much as possible, the shape of the chafing dish needs to be enlarged, that is, the hearth has a limited volume, and in order to avoid the flame being too large relative to the hearth, the output power of a burner is usually reduced, so that NO can be reduced_XConcentration and ensuring sufficient combustion, but the boiler power is therefore reduced and there is a risk of flue gas condensation.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a dimethyl ether gas boiler burner nitrogen reduction device, which solves the technical problem that the heat efficiency of a boiler is reduced when the flame temperature is reduced for reducing nitrogen oxides generated by combustion in the prior art.

The technical scheme of the invention is realized as follows: the utility model provides a dimethyl ether gas boiler combustor nitrogen reduction device, includes the shell body, be provided with whirlwind mechanism in the inner chamber of shell body, the one end of shell body is provided with the hole of induced drafting relative with whirlwind mechanism, and the fire hole has been seted up to the other end of shell body, is provided with the first central spray tube of fuel relative with the fire hole in the shell body, is provided with outer lane flame projecting unit around the shell body.

Further, outer lane bocca unit includes outer lane bocca and central bocca, and outer lane bocca centers on the periphery of central bocca.

Furthermore, the central flame-throwing nozzle is correspondingly provided with a second fuel central spray pipe and is communicated with the inner cavity of the outer shell, and the outer ring flame-throwing nozzle is connected with a fuel outer ring spray pipe.

Furthermore, the outer shell is cylindrical, and the fire outlets are arranged at the outer edge of the end face of the outer shell at equal intervals.

Furthermore, the outer ring flaming units are provided with a plurality of outer ring flaming units, and the plurality of outer ring flaming units are arranged on the periphery of the outer shell at equal intervals.

Further, the outer ring flaming unit comprises an outer ring barrel communicated with the outer shell, the overlooking projection of the outer ring barrel is approximately circular, the central flaming nozzle is arranged at the center of the outer ring barrel, and the outer ring flaming nozzles are arranged on the periphery of the central flaming nozzle at equal intervals.

Furthermore, four central flame nozzles are arranged in each outer ring cylinder, and six outer ring flame nozzles are arranged on the peripheries of the four central flame nozzles.

Further, the inner diameters of the outer ring fire nozzle and the central fire nozzle are 1.5 mm.

Further, the inner diameter of the outer shell is 260mm, and the cyclone mechanism comprises cyclone blades with the length of 100 mm.

Furthermore, the aperture of the air suction hole is 3mm, the inner diameters of the first fuel central spray pipe and the second fuel central spray pipe are 12mm, the inner diameter of the fuel outer ring spray pipe is 8mm, and the diameter of the fire outlet hole is 10 mm.

The invention not only adopts the structure mode of combining the small-bore flame spray nozzle and the flame spray hole to construct the multi-nozzle small-hole flame spray, but also adopts the method of premixing the central flame, thereby reducing the flame temperature and simultaneously not changing the heat efficiency. Because the dimethyl ether fuel gas contains 35 percent of oxygen, the dimethyl ether fuel gas can not absorb more oxygen in the air during combustion. The air-fuel ratio is reasonably proportioned by a premixing method, and the generation of nitrogen oxides is reduced. The emission standard of nitrogen oxides in Beijing and Shanghai is as follows: less than 30 mg per cubic meter. After ten-day combustion tests using the burner of the present invention, the nitrogen oxide emissions were less than 30 mg per cubic meter, only 26 mg, and the thermal efficiency was not reduced.

Drawings

In order to illustrate the embodiments of the invention more clearly, the drawings that are needed in the description of the embodiments will be briefly described below, it being apparent that the drawings in the following description are only some embodiments of the invention, and that other drawings may be derived from those drawings by a person skilled in the art without inventive effort.

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

FIG. 2 is a schematic cross-sectional view of FIG. 1;

in the figure: the method comprises the following steps of 1-outer shell, 2-cyclone mechanism, 21-cyclone blade, 22-rotating shaft, 23-support, 3-air suction hole, 4-fire outlet, 5-first fuel central spray pipe, 6-outer ring fire spraying unit, 61-outer ring fire spraying nozzle, 62-central fire spraying nozzle, 63-outer ring barrel, 7-outer fuel ring spray pipe and 8-second fuel central spray pipe.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive effort based on the embodiments of the present invention, are within the scope of the present invention.

A dimethyl ether gas boiler burner nitrogen reduction device is shown in figure 2 and comprises a cylindrical outer shell 1, wherein the inner diameter of the outer shell 1 is 260 mm. The cyclone mechanism 2 is arranged in the inner cavity of the outer shell 1, the cyclone mechanism 2 comprises cyclone blades 21 with the length of 100mm, the cyclone blades 21 are arranged on a rotating shaft 22, and the rotating shaft 22 is rotatably arranged between the end part of the outer shell 1 and a support 23 of the inner cavity. The shaft 22 is driven by a motor, the mounting position of which is not shown. One end of the outer shell 1 is provided with an air suction hole 3 opposite to the cyclone mechanism 2, and the aperture of the air suction hole 3 is 3 mm. The outside air enters the inner cavity of the outer shell 1 through the air suction holes 3, and is blown to the other end of the inner cavity under the action of the cyclone blades 21.

On the shell body 1, a fire outlet 4 is formed in one end, to which outside air is blown, of the shell body 1, a first central fuel spray pipe 5 opposite to the fire outlet 4 is arranged in the shell body 1, dimethyl ether fuel gas conveyed by the first central fuel spray pipe 5 is premixed with air sucked by the cyclone mechanism 2 in an inner cavity, and then flame is discharged through the fire outlet 4.

As shown in figure 1, a plurality of fire holes 4 are arranged, the fire holes 4 are arranged at the outer edge of the end surface of the outer shell 1 at equal intervals, and the diameter of each fire hole 4 is 10 mm.

Further, an outer ring fire spraying unit 6 is provided around the outer case 1. The outer ring flaming unit 6 comprises an outer ring barrel 63 communicated with the outer shell 1, and air sucked by the cyclone mechanism 2 can enter the outer ring barrel 63. The outer ring barrel 63 is provided with a second fuel central nozzle 8, air sucked by the cyclone mechanism 2 can enter the front end of the second fuel central nozzle 8, and dimethyl ether fuel gas output by the second fuel central nozzle 8 can be premixed with the air sucked by the cyclone mechanism 2 in an outer ring mode.

The combustion end of the outer ring barrel 63 is provided with an outer ring flame projecting nozzle 61 and a central flame projecting nozzle 62, the outer ring flame projecting unit 6 is provided with a plurality of, and the outer ring flame projecting units 6 are arranged at the periphery of the outer shell 1 at intervals. The central flame-throwing nozzle 62 corresponds to the second central fuel-spraying pipe 8 and is communicated with the inner cavity of the outer shell 1, and the outer-ring flame-throwing nozzle 61 is connected with the outer-ring fuel-spraying pipe 7. Dimethyl ether gas output by the fuel outer ring spray pipe 7 is directly combusted through the outer ring flame spray nozzle 61, and dimethyl ether gas output by the fuel second central spray pipe 8 is premixed in the outer ring barrel 63 and then combusted through the central flame spray nozzle 62. The internal diameters of the first central fuel lance 5 and of the second central fuel lance 8 are 12 mm.

Further, the outer ring cylinder 63 is approximately circular in plan view, the center burner 62 is provided at the center of the outer ring cylinder 63, and the outer ring burners 61 are provided at equal intervals on the outer periphery of the center burner 62.

Further, four central torches 62 are provided in each outer ring barrel 63, and six outer ring torches 61 are provided around the four central torches 62. The inner diameters of the outer ring fire nozzle 61 and the center fire nozzle 62 are 1.5 mm.

Nothing in this specification is intended to be exhaustive of all conventional and well known techniques.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. The utility model provides a dimethyl ether gas boiler combustor nitrogen reduction device, includes shell body (1), its characterized in that: the cyclone mechanism (2) is arranged in an inner cavity of the outer shell (1), one end of the outer shell (1) is provided with an air suction hole (3) opposite to the cyclone mechanism (2), the other end of the outer shell (1) is provided with a fire outlet (4), a first central fuel spray pipe (5) opposite to the fire outlet (4) is arranged in the outer shell (1), and outer ring fire spraying units (6) are arranged around the outer shell (1).

2. The dimethyl ether gas boiler burner nitrogen reduction device of claim 1, characterized in that: the outer ring flame-throwing unit (6) comprises an outer ring flame-throwing nozzle (61) and a center flame-throwing nozzle (62), and the outer ring flame-throwing nozzle (61) surrounds the periphery of the center flame-throwing nozzle (62).

3. The dimethyl ether gas boiler burner nitrogen reduction device of claim 2, characterized in that: the central flame-throwing nozzle (62) is correspondingly provided with a second central fuel spray pipe (8) and is communicated with the inner cavity of the outer shell (1), and the outer ring flame-throwing nozzle (61) is connected with an outer ring fuel spray pipe (7).

4. The dimethyl ether gas boiler burner nitrogen reduction device of claim 3, characterized in that: the outer shell (1) is cylindrical, and the fire outlets (4) are arranged at the outer edge of the end face of the outer shell (1) at equal intervals.

5. The dimethyl ether gas boiler burner nitrogen reduction device of claim 3 or 4, characterized in that: the outer ring flaming units (6) are provided with a plurality of flaming units, and the plurality of outer ring flaming units (6) are arranged on the periphery of the outer shell (1) at equal intervals.

6. The dimethyl ether gas boiler burner nitrogen reduction device of claim 5, characterized in that: the outer ring flame-out unit (6) comprises an outer ring barrel (63) communicated with the outer shell (1), the overlooking projection of the outer ring barrel (63) is approximately circular, the center flame-out nozzle (62) is arranged at the center of the outer ring barrel (63), and the outer ring flame-out nozzles (61) are arranged at the periphery of the center flame-out nozzle (62) at equal intervals.

7. The dimethyl ether gas boiler burner nitrogen reduction device of claim 6, characterized in that: four central flame nozzles (62) are arranged in each outer ring cylinder (63), and six outer ring flame nozzles (61) are arranged on the peripheries of the four central flame nozzles (62).

8. The dimethyl ether gas boiler burner nitrogen reduction device according to any one of claims 3, 4 and 5 to 7, characterized in that: the inner diameters of the outer ring fire nozzle (61) and the central fire nozzle (62) are 1.5 mm.

9. The dimethyl ether gas boiler burner nitrogen reduction device of claim 8, characterized in that: the inner diameter of the outer shell (1) is 260mm, and the cyclone mechanism (2) comprises cyclone blades (21) with the length of 100 mm.

10. The dimethyl ether gas boiler burner nitrogen reduction device of claim 9, characterized in that: the aperture of the air suction hole (3) is 3mm, the inner diameters of the first central fuel spray pipe (5) and the second central fuel spray pipe (8) are 12mm, the inner diameter of the outer fuel spray pipe (7) is 8mm, and the diameter of the fire outlet hole (4) is 10 mm.