CN204460213U - A kind of porous gas jet burner - Google Patents

Abstract

The utility model discloses a kind of porous gas jet burner, comprise the outlet of gas pipeline, gas nozzle, air duct and air duct, be combustion gas runner in gas pipeline, the cavity between air duct and gas pipeline is air flow channel; Gas nozzle wall is evenly provided with a circle fire hole, fire hole formed annular ring with the longitudinal center line of gas nozzle for the center of circle, and meet: D _h/ D _b°-150 ° ,=0.4-0.8, d/s=1.5-4, θ=20; By reasonable Arrangement fire hole and spacing, the mixed combustion of combustion gas and air fully can be realized; Porous gas jet, injects incoming air with the direction in a certain angle with nozzle-axis, adopts flared flow can make to form negative pressure on rear side of gas nozzle, realizes high temperature gases recirculating, avoids de-fire and stops working; Air flowing can strengthen negative pressure on rear side of gas nozzle, promotes high temperature gases recirculating, promotes flame stabilization further; Jet-flow injects the shear layer outside recirculating zone, can promote the blending of air and fuel.

Description

A porous gas jet burner

technical field

The utility model relates to an accessory of a gas combustion device, in particular to a porous gas jet burner.

Background technique

The burner is a key part of the gas combustion device, which is commonly found in various combustion-related industrial equipment, such as: boilers, kilns, waste incinerators and gas turbines. A burner with good performance can reasonably organize the mixing of fuel and oxidant, realize safe and stable combustion, and ensure sufficient combustion efficiency and pollutant emission standards. For some special industrial devices, it is also necessary to meet the flexible adjustment requirements of flame length, luminous degree, combustion intensity, combustion temperature and heat load. According to the primary air coefficient, the combustion time can be divided into diffusion combustion, partial premix combustion and complete premix combustion. According to the air supply method, it can be divided into ejection combustion, blast combustion and natural induced draft combustion.

In complete premixed combustion, the fuel and air are completely mixed and evenly mixed before combustion, the combustion speed is very fast, and the volumetric heat intensity is very high. This way can well control the flame temperature and reduce NOx emissions. The complete premixed combustion can adopt the stable combustion of the fire channel, which is prone to backfire when the flow rate is small, and is prone to flameout when the flow rate is large. Completely premixed combustion can also design the head structure as a porous ceramic plate, metal mesh or metal fiber structure. Since the diameter of the fire hole is smaller than the critical hole diameter, tempering will not occur. However, the flow resistance of the combustion nozzle is large and the airflow velocity is small, so it is not suitable for use in high heat load boilers and industrial furnaces. The completely premixed combustion method is also prone to the problem of combustion oscillations.

Partially premixed combustion generally includes an injector, a certain pressure of gas is ejected from the nozzle at high speed, the injected primary air is partially premixed with the gas, and is injected from the burner head burner and mixed with the secondary air for combustion. This type of combustion reduces flame length and soot formation. Partially premixed combustion burners are generally designed in the form of a single flame path (such as a straight pipe), which makes it easy to lose fire or flame out when the combustion load is large. The head can also be designed in the form of multiple fire holes, but the limited dynamic pressure of the fuel jet limits the velocity of the fire hole exit airflow and the heat load of the burner, which is not suitable for industrial applications with high load intensity.

The diffusion combustion method separates air and fuel before combustion, and supplies air during combustion. According to the way of supplying air, it can be divided into the form of spontaneous combustion induced air and forced air. The natural induced draft type is mostly used for civilian use, and is used in occasions where the temperature requirement is not high and the flame stability is good. The forced air combustion method is mainly used in industrial applications. The common form of forced blast is to use swirl flow and many thin fuel jets to enhance the mixing of gas and air to enhance the combustion process and shorten the flame length. This combustion method has a stable flame and is not prone to tempering and defiring. However, this kind of burner contains a complicated swirler structure, and it needs to be forced to be ancient, and the design and manufacturing costs are relatively high.

The above-mentioned existing combustion methods all have the disadvantages of imperfect combustion technology or high design and manufacturing costs. Therefore, it is of great significance for the development of industrial combustion equipment to design a new burner with stable combustion in a large heat load range, moderate flame length, low design and manufacturing costs, and convenient operation and adjustment.

Utility model content

The purpose of this utility model is to provide a porous gas jet burner. The burner has a reasonable structure, can solve the problem of unstable combustion of the combustion device during the change of working conditions, and can ensure that there is no backfire when the fuel flow is small, and the large fuel flow rate is high. Flame-off and flameout do not occur under the flow rate, and combustion oscillation does not occur during the combustion process, and the combustion intensity is increased as much as possible, and the size of the combustion area is reduced.

In order to realize above-mentioned function, the technical scheme of the present utility model is as follows:

A porous gas jet burner, characterized in that it includes a gas pipeline, a gas nozzle, an air pipeline and an air pipeline outlet, the gas pipeline is connected to the gas nozzle, the air pipeline is connected to the air pipeline outlet, and the air pipeline and the gas pipeline are installed coaxially, The air pipe is located outside the gas pipe, the inside of the gas pipe is the gas flow channel, and the cavity between the air pipe and the gas pipe is the air flow channel; the gas nozzle is located at the center of the bell mouth of the air channel of the air pipe, and the gas nozzle wall is uniformly arranged There is a circle of fire holes, and the annular ring formed by the fire hole distribution is centered on the axial centerline of the gas nozzle, and the following three conditions are met at the same time:

The ratio range of D _h /D _b is 0.4-0.8, where D _h is the annular diameter formed by the fire hole distribution, and D _b is the outer diameter of the gas nozzle;

The ratio range of d/s is 1.5-4, where d is the diameter of the fire hole, and s is the distance between the centers of two adjacent fire holes;

θ=20°—150°, where θ is twice the angle between the axis of the fire hole and the axis of the air duct.

The gas nozzle is in the shape of a circular platform, and the fire holes are arranged on the side of the circular platform.

Alternatively, the gas nozzle is in the shape of a cylinder, and the fire holes are arranged on the end surface of the cylinder.

Alternatively, the gas nozzle is in the shape of an inverted cone, and the fire holes are arranged on the end surface of the inverted cone.

The front section of the gas pipeline is a diffuser section with gradually larger caliber, the rear section is a cylindrical section with the same caliber, and the end of the rear section is connected to a gas nozzle through threads.

The outlet of the air duct is in the shape of a bell mouth.

The working principle of the utility model is as follows:

When using the utility model, the gas pipeline is used to provide fuel gas, and the fuel gas can be natural gas, coal gas, biogas and coke oven gas, etc., and the air pipeline is used to provide air. Gas enters from the front end of the gas pipeline, enters the cavity of the gas nozzle through the gas flow channel, and then shoots out from the fire hole. For forced-air combustion, the bell-shaped air duct outlet helps to better organize the flow of air. For the utility model, the air duct and the air duct can also be dismantled, and the gas nozzle part in the middle can be reserved for use.

When there is a high heat load, the gas needs to have a certain pressure to ensure that enough gas is ejected from the fire hole. The air source can be provided by a blower; the utility model can also be installed in a boiler or an industrial furnace, and the negative pressure in the furnace can be used to suck air; the gas suction can also be used to realize combustion in a static atmosphere. The utility model can form a whole with the blower to make an integrated burner; it can also be used as an industrial furnace burner to make a split-type combustion device; it can also be used for the combustion treatment of industrial combustible waste gas and burn in the atmosphere.

The beneficial effects of the utility model are as follows:

(1) By reasonably arranging the fire holes and hole spacing, the air can be fully swept and the mixed combustion of fuel and air can be realized;

(2) The multi-hole fuel jet is used to inject the incoming air at a certain angle with the nozzle axis. This expansion flow will form a negative pressure zone on the rear side of the gas nozzle, which can realize high-temperature flue gas Backflow, which is critical to avoid misfires and flameouts;

(3) The gas nozzle is equivalent to a blunt body. The air jet is injected from around the gas nozzle, and the air flow will increase the negative pressure on the rear side of the gas nozzle, promote the return of high-temperature flue gas, and further promote the stability of the flame; the gas jet is injected into the backflow The shear layer outside the zone can promote the mixing of air and fuel.

Description of drawings

Fig. 1 is the sectional structural representation of the utility model;

Fig. 2 is a schematic diagram of a vertical cross-sectional structure of a gas nozzle of the utility model in the shape of a circular platform;

Fig. 3 is a schematic diagram of the transverse structure of the gas nozzle of the utility model in the shape of a circular platform;

Fig. 4 is the flow field schematic diagram of the present utility model;

Fig. 5 is a schematic diagram of a vertical cross-sectional structure of a gas nozzle of the utility model in a cylindrical shape;

Fig. 6 is a schematic diagram of the horizontal structure of the gas nozzle of the utility model in a cylindrical shape;

Fig. 7 is a schematic longitudinal sectional structural diagram of a conical gas nozzle of the present invention;

Fig. 8 is a schematic diagram of the horizontal structure of the gas nozzle of the utility model in a conical shape;

Wherein, the reference signs are: 1 fire hole, 2 gas nozzle, 3 air pipe outlet, 4 screw thread, 5 air pipe, 6 gas pipe, 7 air flow channel, 8 diffuser section, 9 gas flow channel.

Detailed ways

As shown in Figure 1, a porous gas jet burner includes a gas pipeline 6, a gas nozzle 2, an air pipeline 5 and an air pipeline outlet 3, the gas pipeline 6 is connected to the gas nozzle 2, and the air pipeline 5 is connected to the air pipeline outlet 3 , the air pipeline 5 and the gas pipeline 6 are coaxially installed, the air pipeline 5 is located outside the gas pipeline 6, the gas pipeline 6 is a gas flow channel 9, and the cavity between the air pipeline 5 and the gas pipeline 6 is an air flow channel 7; The gas nozzle 2 is located at the center of the outlet 3 of the air duct.

As shown in Figure 2-3, a circle of fire holes 1 is uniformly arranged on the wall of the gas nozzle 2, and the annular ring formed by the fire holes 1 takes the axial centerline of the gas nozzle 2 as the center.

The structure of the porous gas jet burner needs to meet:

(1) The ratio of D _h /D _b ranges from 0.4 to 0.8, where D _h is the ring diameter formed by the distribution of fire holes 1, and D _b is the outer diameter of the gas nozzle 2;

(2) The ratio range of d/s is 1.5-4, where d is the diameter of the fire hole 1, and s is the distance between the centers of two adjacent fire holes 1;

(3) θ=20°-150°, where θ is twice the angle between the axis of the fire hole 1 and the axis of the air duct 5.

The gas nozzle 2 is in the shape of a circular platform, and the fire hole 1 is arranged on the side of the circular platform.

Alternatively, if the gas nozzle 2 is designed in a cylindrical shape, the fire hole 1 is arranged on the end face of the cylinder, as shown in Fig. 5-6. The position and size of the fire hole 1 still need to meet the above three conditions simultaneously.

Or, if the gas nozzle 2 is designed as an inverted cone, the flame hole 1 is arranged on the end surface of the inverted cone, as shown in Fig. 7-8. The position and size of the fire hole 1 still need to meet the above three conditions simultaneously.

The front section of the gas pipeline 6 is a diffuser section 8 with gradually larger diameters, and the rear section is a cylindrical section with the same diameter, and the end of the rear section is connected to the gas nozzle 2 through a screw thread 4 .

The air duct outlet 3 is bell-shaped.

As shown in Figure 4, the fuel, air flow and combustion area of the utility model are schematically illustrated.

Compared with the existing gas burner technology, the utility model has the following advantages:

(1) When using the utility model, if the gas flow rate is higher, the gas jet turbulence is greater, the ability to sweep the air is stronger, and the strength of the combustion area is also greater; at the same time, the increase of the gas flow rate will also enhance the high-temperature flue gas. Backflow effect, thus avoiding the problem of flameout and flameout;

(2) When the air velocity is small, the mechanism of the gas jet can be used to stabilize the flame; when the air velocity is large, the air can also help the flame to stabilize. Therefore, it can be seen that the burner is less affected by air flow factors and is suitable for various air supply forms.

(3) The diffusion combustion method can effectively avoid the occurrence of combustion oscillation and tempering problems.

(4) The burner can realize the violent mixing of gas and air, shorten the flame length, increase the combustion intensity, and suppress the formation of soot.

(5) Compared with the cyclone structure, forced air blast is not required; and the structure is simple, and the design and manufacturing cost is relatively small.

Claims (6)

1. a porous gas jet burner, it is characterized in that: comprise gas pipeline (6), gas nozzle (2), air duct (5) and air duct outlet (3), gas pipeline (6) is connected with gas nozzle (2), air duct (5) exports (3) and is connected with air duct, air duct (5) and gas pipeline (6) are coaxially installed, air duct (5) is positioned at the outside of gas pipeline (6), be combustion gas runner (9) in gas pipeline (6), the cavity between air duct (5) and gas pipeline (6) is air flow channel (7); Gas nozzle (2) is positioned at the center of air duct outlet (3), gas nozzle (2) wall is evenly provided with a circle fire hole (1), the annular ring that fire hole (1) distribution is formed, and to meet the following conditions for the center of circle with the longitudinal center line of gas nozzle (2) simultaneously:

D _h/ D _bratio range be 0.4-0.8, wherein D _hfor the diameter of the annular ring that fire hole (1) distribution is formed, D _bfor the external diameter of gas nozzle (2);

The ratio range of d/s is 1.5-4, and wherein d is fire hole (1) diameter, and s is the center of circle spacing of adjacent two fire holes (1);

°-150 °, θ=20, wherein θ is 2 times of angle between fire hole (1) axis and air duct (5) axis.

2. a kind of porous gas jet burner according to claim 1, is characterized in that: described gas nozzle (2) is in round table-like, and fire hole (1) is arranged at the side of round platform.

3. a kind of porous gas jet burner according to claim 1, is characterized in that: described gas nozzle (2) is in cylindrical shape, and fire hole (1) is arranged at cylindrical end face.

4. a kind of porous gas jet burner according to claim 1, is characterized in that: described gas nozzle (2) is in back taper, and fire hole (1) is arranged at the end face of back taper.

5. a kind of porous gas jet burner according to claim 1, it is characterized in that: the leading portion of described gas pipeline (6) is the diffuser (8) that bore becomes large gradually, back segment is the cylindrical section that bore is equal, and the end of back segment connects gas nozzle (2) by screw thread (4).

6. a kind of porous gas jet burner according to claim 1, is characterized in that: described air duct outlet (3) is toroidal.