KR20020032494A - Gasboiler with Premixed flame burner - Google Patents

Abstract

PURPOSE: A gas boiler is provided to reduce the fail of the fire-ignition by allowing a mixing fluid of gas and air to be mixed while passing through the first and second mixing rods before the mixing fluid reaches a combustion section. CONSTITUTION: A hollow burner body(10) is vertically formed. A blower(12) is installed below the hollow burner body(10) so as to blow air. Gas is injected towards the blower(12) by a gas injection nozzle(21). The first mixing section(20) is positioned in an upper portion of the gas injection nozzle(21) so as to mix gas with air. A plurality of first mixing rods(26) are vertically arranged with respect to a flow direction of the mixing fluid so as to form the second mixing section(25). A plurality of second mixing rods(27) are arranged in parallel to the first mixing rods(26). The third mixing section(28) is formed at an upper portion of the second mixing rods(27). A flame holder(30) is positioned above the third mixing section(28). An ignition device(36) is positioned above the flame holder(30).

Description

Gas boiler with premixed flame burner

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas boiler, and more particularly, to reduce the amount of carbon monoxide emitted from a gas boiler, a gas having a premixed flame burner having a configuration of mixing gas and air in close proximity to an ignitable mixing ratio before combustion. It is about a boiler.

In general, a burner is a device that burns fuel safely and efficiently to obtain heat.It is a gas burner for gas combustion, an oil burner for burning liquid fuel such as kerosene or heavy oil, a pulverized coal burner for coal combustion, etc., depending on the type of fuel. There is this. In addition, it is divided into a premixed burner and a diffusion burner according to a method of mixing fuel and air. Pre-mixed burners pre-mix fuel and air to combust, and diffusion-type burners send fuel and air to the combustor separately to mix and combust them in the combustor.

Most of the burners currently used in domestic gas boilers are bunsen burners which are diffusion type burners.

4 is a schematic cross-sectional view of a conventional Bunsen burner. As shown in FIG. 4, in the combustion process of the Bunsen burner 50, a mixed gas in which gas and primary air 46 are mixed is combusted in the combustion 45 part, and the combustion part 45 is used to assist the combustion. The secondary air 47 is introduced into the furnace to cause diffusion combustion.

In the case of diffuse combustion, oxygen is insufficient at the center of the flame and gas is excessive. At the edge of the flame, gas is insufficient and oxygen is excessive. At this time, the gas and fuel are directed toward the intermediate point due to the difference in concentration of gas and oxygen. Diffusion continues and combustion continues. At this time, some of the carbon monoxide generated in the center of the flame is not oxidized to carbon dioxide during the diffusion combustion process is released as carbon monoxide as it is.

This is mainly a problem in the small burner. In the large burner, the combustion space inside is large, so that the carbon monoxide generated stays at a certain time where the carbon monoxide is more than 900 degrees. At this time, the carbon monoxide is combined with oxygen to form carbon dioxide. Due to the narrow space, the residence time at 900 degrees or more is so short that the emission of carbon monoxide, which cannot be oxidized to carbon dioxide, is large, and the concentration of carbon monoxide in the exhaust gas cannot be lower than 150 ppm even under optimal conditions of the burner.

Therefore, when the exhaust gas is not discharged smoothly or when the exhaust gas penetrates the inside of the building, the work environment is deteriorated in the industrial field, which reduces work efficiency and greatly threatens the health of workers and even lives. It could be lost, and at home there was a problem that cannot be overlooked such as threatening health and life.

In addition, the fact that the gas is not oxidized to carbon dioxide by the complete combustion and part of the carbon monoxide is discharged, because the boiler does not obtain the heat generated when the carbon monoxide is oxidized to carbon dioxide, there is a problem that the efficiency of the boiler is lowered.

In addition, in order to ignite, in addition to the ignition temperature, the ignition is performed only when the mixing ratio of gas and oxygen reaches a certain standard. In the conventional gas boiler, it is difficult to control the mixing ratio when the gas and oxygen are actually mixed. .

The present invention has been made to solve the above problems, an object of the present invention is to mix each of the mixture through the first mixing rod and the second mixing rod before the primary mixed gas of gas and air reaches the combustion section It is to provide a gas boiler having a premixed flame burner that allows the secondary mixing by the turbulent flow generated from the rod, so that combustion occurs near the ignitable mixing ratio.

An object of the present invention as described above, the burner body 10 is built up in the vertical direction; A blower 12 installed below the burner body 10 to introduce air; A gas injection nozzle 21 for injecting the gas 22 toward the blower 12; A first mixing unit 20 disposed above the gas injection nozzle 21 and mixing the gas 22 and air; A plurality of first mixing rods 26 arranged in a vertical direction with respect to a traveling direction of the mixed gas in which the gas 22 and air are mixed to form a second mixing portion 25; A second mixing rod 27 arranged on the upper portion of the first mixing rod 26 in a direction parallel to the first mixing rod 26 to form a second mixing portion 25; A third mixing unit 28 formed on an upper portion of the second mixing rod 27; A plate-shaped flame holder 30 positioned above the third mixing unit 28 and having a plurality of combustion unit inlets 31 formed therein to allow the mixed gas to pass therethrough; And an ignition device (36) positioned above the flame holder (30).

The first mixing rod 26 and the second mixing rod 27 preferably have a circular cross section, and the second mixing rod 27 preferably has a larger diameter than the first mixing rod 26.

In addition, the flame holder 30 has a shape of a plate and a flame holder main body 33 in which the combustion part inlet 31 of the same size is uniformly arranged; And a coolant pipe 32 formed on the surface of the flame holder main body 33 in the direction of the third mixing part 28 and positioned between the combustion inlet portions 31 and connected to each other.

In addition, in order to achieve the above object, it is preferable that a plurality of gas injection nozzles 21 are formed.

Other objects, specific advantages and novel features of the invention will become more apparent from the following detailed description and the preferred embodiments associated with the accompanying drawings.

1 is a cross-sectional view schematically showing a part of a gas boiler having a premixed flame burner according to an embodiment of the present invention;

2 is a front view of the flame holder according to an embodiment of the present invention,

3 is a rear view of the flame holder according to an embodiment of the present invention,

4 is a schematic cross-sectional view of a conventional Bunsen burner.

Hereinafter, a configuration of a gas boiler having a premixed flame will be described with reference to the accompanying drawings.

1 is a schematic cross-sectional view of a gas boiler having a premixed flame burner according to an embodiment of the present invention. As shown in FIG. 1, the burner body 10 is vertically formed along the advancing direction of the mixed gas 23. The blower 12 is formed in the lowermost part of the burner body 10 in order to mix gas 22 and air primarily. The gas injection nozzle 21 is installed toward the blower 12 to inject the gas 22 in a direction opposite to the flow of air flowing through the blower 12, and is divided and sprayed at various positions for effective mixing. The number and inner diameter of the gas injection nozzle 21 differ depending on the fuel. In order to obtain 2000 kcal of heat using natural gas as fuel, 13 gas injection nozzles 21 having an inner diameter of 1.34 mm are used.

The first mixing unit 20 is about 50 mm from the gas injection nozzle 21 in order to sufficiently mix the air and the gas 22 flowing from the blower 12 to reach the second mixing unit 25. It is formed over the interval.

The first mixing rod 26 is a secondary mixing of the air and the gas 22 by the vortex generated by the mixing gas 23 passing through, the position of about 70mm upward from the gas injection nozzle 21 In the inside of the burner body 10 is formed side by side so that all the mixed gas 23 passes through. The first mixing rods 26 are made of stainless steel, the diameter of 2mm, each of the first mixing rods 26 are arranged in one row at intervals of about 4mm, each row is about 3mm 3 to 4 columns are arranged at intervals of.

The second mixing rod 27 mixes the mixed gas 23 flowing into the third mixing portion 28 formed just before the combustion portion 35 is close to the ignitable mixing ratio, and is made of stainless steel and has a diameter. 1 mm, each of the second mixing rods 27 are arranged in about 100 rows in one row at intervals of about 2 mm, and two to three rows are disposed at intervals of about 3 mm in each row.

The third mixing unit 28 is a final mixing unit before reaching the combustion unit 35, and is a section in which mixing is performed only by diffusion of gas, and the second mixing rod 27 is used for mixing at the molecular scale required for complete combustion. ) Is formed over a section of about 50 mm.

The flame holder 30 is used to uniformly change the inflow velocity of the mixed gas 23 according to positions and prevent combustion at the rear of the flame holder 30. The flame holder 30 is about 70 mm above the second mixing rod 27. It is formed in the position, the inside of the burner body 10 is largely blocked by the combustion section 35 and the mixing section (20, 25, 28).

The ignition device 36 is installed above the flame holder 30 by causing the flame 37 to ignite the mixed gas 23, and the upper part of the flame holder 30 including the ignition device 36 is sparked. The combustion section 35 which generates heat by 37 is formed.

2 is a front view of the flame holder 30 according to an embodiment of the present invention. As shown in FIG. 2, the flame holder 30 has a plurality of combustion part entrance openings 31 having a dimension of about 5 mm in length and 1 mm in length, and the speed of the mixed gas flowing therein is 10 m / s to 30 m / s. A flame holder body 33 which is in the shape of a plate having a thickness of about 0.3 mm which is adjusted and formed of stainless steel having fire resistance; And a coil (not shown) for cooling air on one surface of the flame holder main body 33 to prevent combustion at the rear of the flame holder main body 33 by lowering the temperature at the rear of the flame holder main body 33. The cooling water pipe 32 is comprised.

3 is a rear view of the flame holder 30 according to an embodiment of the present invention. As shown in FIG. 3, the coolant pipe 32 is installed to avoid the combustion inlet 31 from the flame holder body 33 so as not to block the inflow of the mixing gas 23 into the combustion section 35. Passed and connected across the front of the flame holder body 33 for cooling.

The flame holder 30 rises in temperature due to the radiant heat received from the flame 37, transmits radiant heat to the mixing rods 26 and 27 at the back of the flame holder 30, and receives the mixed rods 26 and 27. ) Are eventually transferred from the flame holder 30 to air by a process that is cooled by air. However, the process of directly cooling the flame holder 30 while the air passes through the flame holder 30 transfers more heat than the above process. Separately there is a coolant pipe 32 for cooling the air and flame holder 30. The coolant pipe 32 not only cools the air but also cools the flame holder 30 by exchanging radiant heat directly with the flame holder 30. Although not shown in the drawings, the water flowing through the coolant pipe 32 does not require a separate circulation pump because the water is piped through the coolant pipe 32 first before the heating water enters the heat exchanger (not shown).

Hereinafter, a method of operating a gas boiler having a premixed flame burner according to the present invention will be described.

The air flowing into the premixed flame burner through the blower 12 is primarily mixed with the gas 22 injected from the gas injection nozzle 21 by turbulent flow when exiting the blower 12. At this time, in order to sufficiently mix the air and the gas 22, the gas 22 is injected in a direction against the flow of air from a plurality of gas injection nozzles 21, and the gas 22 and the mixed gas 23 of the air 23 ) Is generated.

In the sense of mixing, the mixing scale is important. For example, when mixing on a 1 mm scale, it means that any 1 mm portion of the mixed gas is mixed evenly. This means that when analyzing 1 mm or less, for example, 0.1 mm portion, It may not be mixed.

Laminar flow occurs in front of the first mixing rod 26 when the mixed gas 23 passes the first mixing rod 26 after passing through the primary mixing portion 20, In the back, various sizes of vortices occur, where the size of the vortices is determined by the diameter of the first mixing rod 26, the largest being about 50% of the diameter of the first mixing rod. Due to the pulsation of air by the vortex, the gas 22 and the air are mixed on the scale of the diameter of the first mixing rod 26.

In order to achieve sufficient mixing without significantly reducing the speed of the mixing gas 23, the distance between each of the first mixing rods 26 positioned in the same row is about 4 mm, and the first mixing rods 26 are arranged in multiple rows. do.

When the mixed gas 23 passes the second mixing rod 27, secondary mixing of the gas 22 and air occurs due to the vortex generated at the rear of the second mixing rod 27. Since the mixed gas 23 passing through the second mixing rod 27 flows into the third mixing unit 28 located immediately before the combustion unit 35, the second mixing rod 27 is closer to the mixing ratio that can be ignited. Sufficient mixing must be achieved. In consideration of this, the diameter of the second mixing rod 27 is about 1 mm and is arranged in multiple rows, and the mixed gas 23 through the mixing is mixed up to a scale of about 1 mm.

The mixed gas 23 reaching the third mixing part 28 is mixed up to a scale of about 1 mm, and then mixing occurs by diffusion of gas in the third mixing part 28. The gas that reaches the third mixing section 28 is mixed at an instant ignitable mixing ratio because the distance to diffuse for the two gases to be completely mixed is very small.

After the final mixing, the mixed gas 23 enters the flame holder 30, where the speed of the mixed gas 23 varies from position to position, and for the even combustion in the combustion section 35, You need to equalize the speed. The combustion part inlet 31 causes a large pressure drop in the mixed gas 23 through the drastic reduction of the flow path area, and after passing through the combustion part inlet 31, the speed of the mixed gas 23 becomes almost uniform.

The mixed gas 23 passing through the flame holder 30 is ignited by the ignition device 36 which is located in the combustion section 35 and generates the flame 37, and continues combustion to thereby heat the boiler. Generate. In this case, in order to prevent combustion from occurring at the rear of the flame holder 30, a coolant pipe 32 is installed at the rear of the flame holder 30, and the temperature of the flame holder 30 is ignited by the coolant pipe 32. No combustion occurs because the temperature is not reached.

Although not shown in FIG. 1, after the mixed gas 23 is combusted in the combustion unit 35, the combustion gas flows into the heat exchanger (not shown) through the inside of the boiler, thereby exchanging heat exchanger (not shown). Heat exchange with the, and the combustion gas after the heat exchange is discharged to the outside through the combustion gas outlet (not shown in the figure).

On the other hand, the present invention can of course be applied not only to domestic gas boilers, but also to research and industrial small gas boilers.

On the other hand, in the embodiment of the present invention, the mixing rods 26 and 27 used 400 as the material of stainless steel, but can be used copper or other materials without departing from the spirit and scope of the present invention, the mixing rod (26) 27) is not limited to arranging two types of mixing rods in two stages, and the dimensions can be further subdivided and arranged in three stages, four stages, and the like in three or four kinds. In the case of the spacing between the mixing rods, depending on the use environment, it may be selected to reduce the number of rows instead of narrowly spaced, or to increase the number of rows instead of widening the interval.

In the case of the flame holder 30, the material of the flame holder main body 33 may be made of ceramics, and the shape of the combustion inlet 31 is not limited to the quadrangle, and other deformed shapes such as a circular or an elliptical spiral may be used. Include.

According to the domestic gas boiler having the premixed flame burner according to the present invention having the above-described configuration, since sufficient mixing is performed by the first mixing rod and the second mixing rod before the mixed gas of gas and air reaches the combustion section, Combustion occurring in the combustion unit is close to complete combustion, and thus, the efficiency of the boiler is improved and the carbon monoxide emissions are significantly reduced.

In addition, in the conventional gas boiler, the actual mixing ratio of gas and air is higher or lower than the ignition possible mixing ratio, but the ignition is poor. However, in the present invention, the failure of the ignition is significantly reduced because the gas and air reach the combustion unit in a completely mixed state. .

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications or variations without departing from the spirit and scope of the invention. Accordingly, the appended claims will cover such modifications and variations as fall within the spirit of the invention.

Claims (4)

In a gas boiler having a premixed flame burner, An empty burner body 10 which is erected in a vertical direction; A blower 12 installed at a lower portion of the burner body 10 to introduce air; A gas injection nozzle 21 for injecting a gas 22 toward the blower 12; A first mixing unit 20 disposed above the gas injection nozzle 21 and mixing the gas 22 with air; A plurality of first mixing rods 26 arranged in a direction perpendicular to a traveling direction of the mixed gas in which the gas 22 and air are mixed to form a second mixing portion 25; A second mixing rod (27) arranged on the upper portion of the first mixing rod (26) in a direction parallel to the first mixing rod (26) to form a second mixing portion (25); A third mixing unit 28 formed on an upper portion of the second mixing rod 27; A plate-shaped flame holder (30) positioned above the third mixing portion (28) and having a plurality of combustion portion entry ports (31) formed therein to allow the mixed gas to pass therethrough; And Gas boiler having a pre-mixed flame burner, characterized in that it comprises an ignition device (36) located on top of the flame holder (30). The method of claim 1, wherein the first mixing rod 26 and the second mixing rod 27 has a circular cross section, the first mixing rod 26 has a larger diameter than the second mixing rod 27 A gas boiler having a premixed flame burner. The method of claim 1, wherein the flame holder 30, A flame holder body 33 having a plate shape and having the same size combustion chamber entry holes 31 arranged uniformly; And It is characterized in that it comprises a coolant pipe 32 is formed on the surface of the flame holder body 33 in the direction of the third mixing portion 28, located between each combustion inlet 31 and connected to each other. Gas boiler having a premixed flame burner. The gas boiler according to claim 1, wherein a plurality of the gas injection nozzles (21) are formed.