JP2001165414A - Burner for heating furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a burner for a heating furnace, the burner being compactly fabricated with low cost and generating only a low amount of NOx. SOLUTION: The burner has a liquid fuel injection port 11o and a plurality of gaseous fuel injection ports 11g, wherein the port 11o atomizes the liquid fuel supplied under pressurized state during injection thereof, while the ports 11g are arranged around the port 11o and inject the gaseous fuel in the direction substantially parallel to the injecting direction of liquid fuel from the port 11o. A main flame provided by the liquid fuel injected from the injection port 11o is provided with ancillary flames provided by the gaseous fuel injected from the plurality of injection ports 11g.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a burner for a heating furnace.

[0002]

2. Description of the Related Art Such a furnace heating burner (hereinafter, sometimes simply referred to as a burner) is installed so as to eject fuel into a furnace, and the fuel ejected from the burner is used for combustion. The furnace is heated by combustion air supplied from the air supply unit into the furnace. In burning such a burner, it is desired to reduce the amount of NOx generated. To achieve this, it is necessary to increase the emissivity of the combustion flame and lower the temperature, and to heat the burner more effectively by radiant heat. Therefore, in such a burner, combustion is performed at a low air ratio as much as possible so that the emissivity becomes as high as possible to cause slow combustion.

In such a burner, conventionally, a liquid fuel ejection hole for ejecting liquid fuel supplied in a pressurized state, and a collision with the ejected liquid fuel for atomizing the liquid fuel ejected from the liquid fuel ejection hole. And an atomizing air ejection hole for ejecting air supplied in a pressurized state (hereinafter, may be referred to as an air atomizing type) so that a liquid fuel supplied in a pressurized state is supplied. A liquid fuel ejection hole to be ejected, and an atomizing gas ejecting a gas fuel supplied under pressure so as to collide with the ejected liquid fuel in order to atomize the liquid fuel ejected from the liquid fuel ejection hole. A fuel atomizing hole (hereinafter, sometimes referred to as a gas atomizing type), and a liquid fuel jetting hole for making liquid fuel supplied in a pressurized state into an atomized state along with jetting. Things (hereafter, May be described as the body fuel-fired type) it has been proposed.

[0004]

However, each of the above-mentioned conventional burners has the following problems. In the air atomizing type burner, since the liquid fuel is atomized by air, it is necessary to jet air at a high pressure. For example, when the combustion amount is 2325 kW or more, 0.9
It is necessary to increase the pressure to about 8 MPa (gauge pressure, the same applies hereinafter). However, an air compressor for supplying air in a pressurized state becomes special and expensive if it has a pressure increasing capability of about 0.98 MPa or more.

In the gas atomizing type burner, the gas fuel must be jetted at a high pressure in order to atomize the liquid fuel with the gas fuel. For example, when the combustion amount is 2325 kW or more, the gas fuel pressure becomes zero. .49 to 0.59 MPa
Degree is required. However, the supply pressure of city gas as an example of gas fuel is usually 0.29 MPa or less, and if the supply pressure is 0.29 MPa or more, it is treated specially and costs increase. On the other hand, with a gas fuel having a supply pressure of 0.29 MPa or less, which is a normal supply pressure of city gas,
When trying to atomize liquid fuel, the diameter of the gas fuel
Also, it is necessary to increase the diameter of the gas fuel path for guiding the gas fuel to the gas fuel ejection hole, and accordingly, the burner body including the gas fuel path and the like becomes large,
Not practical. For example, if the combustion amount is 2325 kW
In the case described above, the outer diameter of the burner body needs to be larger than 100 mm, which is not practical.

[0006] Since the liquid is easy to apply pressure, the liquid fuel sintering type can have a relatively simple configuration even with a burner with a high combustion amount. The liquid fuel sintering type is compared with the air atomizing type and the gas atomizing type described above. And can be offered at low prices. However, in the liquid fuel combustion type, when the air ratio is low, soot is easily generated and a flame is difficult to be formed. On the other hand, when the air ratio is high, the temperature of the combustion flame increases and the amount of NOx generated increases. In terms of reducing the generation amount of NOx, it was inferior to the above-mentioned air atomizing type and gas atomizing type.

[0007] The present invention has been made in view of such circumstances, and its object is to provide a small-sized, low-cost, and
An object of the present invention is to provide a furnace heating burner that generates a small amount of NOx.

[0008]

Means for Solving the Problems [Invention according to claim 1]
2. The liquid fuel injection hole according to claim 1, wherein the liquid fuel is supplied in a pressurized state, and the liquid fuel is injected into an atomized state along with the injection. A plurality of gas fuel ejection holes for ejecting gas fuel in a direction parallel or substantially parallel to the liquid fuel ejection direction from the ejection holes, and ejected from the liquid fuel ejection holes,
The liquid fuel combustion flame burning as the main flame is ejected from the plurality of gas fuel ejection holes, and is configured to be supplemented by the gas fuel combustion flame burning as the supplementary flame. According to the characteristic configuration of the first aspect, the liquid fuel supplied to the liquid fuel ejection hole in a pressurized state is ejected from the liquid fuel ejection hole in an atomized state, burns as a main flame, and the liquid fuel is ejected. From the gas fuel vent around the hole, gas fuel
The fuel is ejected in a direction parallel or substantially parallel to the direction in which the liquid fuel is ejected from the liquid fuel ejection hole, and burns as a supplementary flame so as to supplement the liquid fuel combustion flame burning as the main flame. In other words, the gas fuel does not need to atomize the liquid fuel, so the gas fuel supply pressure does not require a high supply pressure as in a conventional gas atomizing type burner. A supply pressure lower than the supply pressure of 0.29 MPa is sufficient. Further, since it is not necessary to atomize the liquid fuel with the gas fuel, even if the supply pressure of the gas fuel is lower than the normal supply pressure of the city gas of 0.29 MPa, the burner combustion amount is increased. Also, it is possible to prevent the diameter of the gas fuel path for guiding the gas fuel to the gas fuel ejection hole from becoming excessive, and to reduce the size of the burner main body including the gas fuel path therein. Further, since the liquid is easily applied with pressure, the liquid fuel supplied to the liquid fuel ejection hole can be easily pressurized to a predetermined pressure by using a generally used low-cost pump or the like. Further, since the liquid fuel combustion flame burning as the main flame is supplemented by the gas fuel combustion flame burning as the supplementary flame, the generation of soot is reduced and the low air Since the slow combustion can be effectively caused by the ratio, the emissivity of the combustion flame can be increased and the temperature can be decreased, so that the generation amount of NOx can be reduced. Accordingly, it has become possible to provide a burner for heating a furnace which is small in size and low in price and generates a small amount of NOx.

Further, since the liquid fuel and the gas fuel are burned, the liquid fuel such as heavy oil corresponding to the amount of the gas fuel burned can be reduced as compared with the conventional liquid fuel combustion type. It is possible to reduce the emission of SOx in an amount corresponding to the reduction amount of SOx. Further, since the liquid fuel combustion flame burning as the main flame is supplemented by the gas fuel combustion flame burning as the supplementary flame, stable combustion can be performed over a wide combustion amount range, so that the turndown ratio is increased. And emission of carbon dioxide can be reduced.

According to a second aspect of the present invention, a total combustion amount including the combustion amount by the liquid fuel and the combustion amount by the gas fuel is 3000 kW or more. When the present invention is applied to a high-load burner in which the total amount of combustion of the liquid fuel and the amount of combustion of the gas fuel is particularly 3000 kW or more, it is possible to reduce the size, The effect of the present invention that the cost can be reduced and the generation amount of NOx can be reduced can be made more remarkable, which is preferable.

According to a third aspect of the present invention, the amount of combustion by gaseous fuel is 1 to 30 times the total amount of combustion by the amount of combustion by liquid fuel and the amount of combustion by gaseous fuel. %. In other words, when the ratio of the amount of combustion by gas fuel to the total amount of combustion is reduced, the supplementary action by the gas fuel combustion flame tends to be weakened. The burner body tends to be larger. According to the characteristic configuration of the third aspect, since the combustion amount by the gas fuel is 1 to 30% of the total combustion amount, the increase in the diameter of the gas fuel path is suppressed and the supplementation by the gas fuel combustion flame is suppressed. Flame action can be strengthened. Therefore, it is possible to provide a specific configuration suitable for making the effects of both miniaturization and reduction of the amount of generated NOx more remarkable.

According to a fourth feature of the present invention, the outer shape is formed in a columnar shape, and the inside thereof has
A burner main body including a liquid fuel path for guiding liquid fuel to the liquid fuel ejection hole and a gas fuel path for guiding gas fuel to the plurality of gas fuel ejection holes with the respective flow path longitudinal directions along the column longitudinal direction is provided. The configuration is such that the diameter is in the range of 65 to 100 mm. According to the characteristic configuration of the fourth aspect, for example, the total combustion amount is 3000 to 9000 k
The burner in the range of W has an outer diameter of the burner body of 65 to 100.
mm. That is, according to the present invention, the outer diameter of the burner main body is 65 to 100 mm even with a high-load burner having a total combustion amount in the range of 3000 to 9000 kW.
It can be configured to be small enough to fit in the range.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, the burner B for the heating furnace includes a liquid fuel ejection hole 11o that makes the liquid fuel supplied in a pressurized state into an atomized state with the ejection, and
A plurality of gas fuel ejection holes 11g located around the liquid fuel ejection holes 11o and ejecting gas fuel in a direction parallel to the liquid fuel ejection direction from the liquid fuel ejection holes 11o.
Is attached to a burner body 12 having a cylindrical outer shape, and a liquid fuel path 13 and a gas inside the burner body 12 for guiding liquid fuel to a liquid fuel ejection hole 11o. Fuel is supplied to a plurality of gas fuel injection holes 1
The gas fuel passages 14 leading to 1 g are provided in such a manner that the longitudinal directions of the respective flow paths extend along the longitudinal direction of the cylinder.

As shown in FIGS. 3 and 4, the nozzle tip 11 is formed on a disk with a circular liquid fuel ejection hole 11o such that its axis Po is coaxial with the center of the disk. Along the circumference of an imaginary circle concentric with the axis Po of the liquid fuel ejection hole 11o, eight circular gas fuel ejection holes 11g are formed, each having the same diameter, and each axis Pg being provided with the liquid fuel. Shaft core P of jet hole
It is formed at equal intervals in a state parallel to o.

The burner main body 12 is formed by using a cylindrical material having one end closed so that the outer shape is cylindrical. The burner main body 12 is provided with a cooling jacket 15 along the inner peripheral surface thereof, and has a circular hole 12w for mounting a nozzle tip on one end side of the cylindrical peripheral wall. The burner is cooled by water or air by passing cooling water or cooling air through the cooling jacket 15. Then, inside the burner body 12, the cylindrical gas fuel path 14 is bent at one end while the longitudinal direction of the gas fuel path 14 is aligned with the longitudinal direction of the cylinder.
The opening is connected to a circular hole 12 w for mounting the nozzle tip, and the other end is bent so as to protrude from the peripheral wall of the cylinder. One end of the passage 13 is bent in a state where the longitudinal direction of the flow path is along the longitudinal direction of the cylinder, the opening is positioned at the center of the circular hole 12 w for mounting the nozzle tip, and the other end is a cylinder. It is provided so as to protrude from the end.

The nozzle tip 11 is connected to the gas fuel passage 14 by eight circular gas fuel jet holes 11g.
In a state where the liquid fuel ejection hole 11o communicates with the liquid fuel path 13, it is attached to the circular hole 12w for mounting the nozzle tip by welding or a screw method.

A gas fuel supply path 16 such as a city gas supply pipe is connected to the gas fuel path 14, and the gas fuel supply path 16 is connected to the gas fuel supply path 16 for interrupting the supply of gas fuel. A gas on-off valve 17 and a gas fuel regulating valve 18 for regulating a supply amount are provided. The liquid fuel path 13 is connected to a liquid fuel supply path 20 to which the liquid fuel is supplied in a pressurized state by a pump 19, and the liquid fuel supply path 20 is connected to the liquid fuel supply opening / closing opening / closing liquid fuel. Valve 21 and liquid fuel regulating valve 2 for regulating supply amount
2 is provided.

That is, with respect to the liquid fuel ejection hole 11o,
The liquid fuel is supplied in a pressurized state through the liquid fuel passage 13, and the liquid fuel is ejected from the liquid fuel ejection hole 11o in an atomized state. The eight gas fuel ejection holes 11g located around the liquid fuel ejection hole 11o are provided. From the liquid fuel ejection hole 11o, the gas fuel is ejected in a direction (direction of the axis Pg) parallel to the direction of ejecting the liquid fuel (the direction of the axis Po). Then, combustion air is supplied from a combustion air supply unit separately provided in a furnace body or the like, and the liquid fuel ejected from the liquid fuel ejection holes 11o is burned as a main flame, and the eight gas fuel ejection holes 11g are burned. The gas fuel ejected from the fuel is burned so as to supplement the liquid fuel combustion flame.

By configuring the burner as described above, the amount of combustion by gas fuel is made 30% of the total amount of combustion by liquid fuel and the amount of combustion by gas fuel, and the total amount of combustion is 3,000 to 3,000. In the case of a range of 9000 kW, a case in which heavy fuel oil A is used as the liquid fuel and a city gas of 13 A is used as the gas fuel, the outer diameter D of the burner body 12 is in the range of 65 to 100 mm, and the length L of the burner body is L.
In the range of 1000 to 2000 mm, and the outer diameter W of the nozzle tip in the range of 25 to 40 mm. or,
The supply pressure of the gaseous fuel can be about 0.098 MPa or less, and the supply pressure of the liquid fuel can be about 1.96 MPa.
For example, when the total combustion amount is 9000 kW, the gas fuel is supplied at a supply pressure of about 0.098 MPa and the total combustion amount is 5000
At kW, the gas fuel is supplied at a supply pressure of about 0.05 MPa. When the total combustion amount is 3000 kW, the gas fuel is supplied at 0.1 MPa.
Each can be supplied at a supply pressure of about 029 MPa. By the way, when using C heavy oil as liquid fuel,
The supply pressure of the liquid fuel can be set to about 2.94 MPa.

Next, a glass melting furnace, which is an example of a heating furnace employing the burner B configured as described above, will be described with reference to FIGS. The glass melting furnace is configured such that a melting body 2 is provided at a lower portion and a furnace body 1 having an arched ceiling is provided at the center, a glass material is charged from one end of the melting tank 2, and molten glass is taken out from the other end. Then, with respect to the transfer direction T of the glass raw material,
The heat storage chamber 3 is extended along the raw material transfer direction T, and a plurality of air ports (so-called ports) 5 are provided above the right and left furnace walls 4 of the furnace body 1.
Are arranged side by side along the raw material transfer direction T, and the heat storage chamber 3 and each air port 5 are communicated with each other through an air supply path 6 to form a so-called side port type. Two burners B are provided for each of the air ports 5, with the portions where the respective nozzle tips 11 are located in the air ports 5, so as to form a so-called through-port type.

The left and right burners B are operated for a certain time (about 15 to 3).
0 minutes), the fuel F (liquid fuel and gaseous fuel) is alternately jetted and stopped, and from the air port 5 on the side of the burner B which is jetting the fuel F, the heat passes through the heat storage chamber 3 to reach a high temperature. (9
Combustion air A preheated to about 100 to 1000 ° C.) is supplied to the furnace 8, and the combustion gas E in the furnace 8 is supplied from the air port 5 on the side of the burner B which stops the injection of the fuel F. The so-called alternating combustion is performed in which the left and right burners B are burned alternately by discharging. 5 and 6 show a state where the left burner B is burning and the right burner B is extinguished.

Combustion air A is supplied from an air port 5 provided with a burner B which is ejecting the fuel F around the fuel F ejected from the burner B along the ejection direction. And the combustion air come into contact and diffuse combustion, so-called slow combustion, a long, high-luminance combustion flame (bright flame)
Is formed, and the glass material in the melting tank 2 is melted by the radiant heat of the combustion flame. The arched ceiling of the furnace body 1
Reflects the radiant heat of the combustion flame. The combustion gas E in the furnace 8 is
The fuel F flows into the heat storage chamber 3 from the air port 5 on the side of the burner B where the ejection of the fuel F is stopped, passes through the heat storage material, and is exhausted after exhaust heat is recovered by the heat storage material. In the heat storage chamber 3,
When the combustion gas E is discharged, the exhaust heat is recovered from the combustion gas E to the heat storage material to store the heat, and when the combustion air A is supplied, the combustion air A is preheated by the heat storage of the heat storage material. . The combustion air A thus preheated
Is supplied to the furnace 8 from the air port 5 through the air supply path 6.

An inlet 4i is formed in the furnace wall 4 of the furnace body 1,
A work tank 9 is provided outside the furnace wall 4 facing the furnace wall 4 having the inlet 4i formed therein, and a take-out hole 4e for communicating the work tank 9 with the melting tank 2 is formed in the furnace wall 4. 4
The glass raw material supplied from i is melted in the melting tank 2 and flows down toward the work tank 9, and the clean molten glass is guided to the work tank 9 through the extraction hole 4 e.

The results of comparing the performance of the burner according to the present invention with that of the conventional burner of the liquid fuel firing type using the glass melting furnace configured as described above will be described. In addition, the total combustion amount of both burners is 3000 kW. FIG. 7 shows the distribution of the emissivity along the longitudinal direction of the combustion flame, and FIG. 8 shows the distribution of the temperature along the longitudinal direction of the combustion flame. As a result, broken line shows the result of the conventional liquid fuel burner type burner. 7 and 8, it can be seen that the burner according to the present invention has a higher emissivity of the combustion flame and a lower temperature than the conventional burner of the liquid fuel only type. As a result, it was found that the burner according to the present invention can reduce NOx emission by about 20% as compared with the conventional burner of the liquid fuel combustion type. Further, in the burner according to the present invention, compared to conventional liquid fuel-fired burner 25% of the emissions of SOx, CO ₂ emissions were found to be capable of respectively reduced by about 20%. The turndown ratio is about 1: 2 in the conventional burner of the liquid fuel type, whereas it is about 1: 5 in the burner according to the present invention.
It was found that the turndown ratio could be increased.

[Another Embodiment] Next, another embodiment will be described. (A) In the above embodiment, the case where the nozzle tip 11 is attached to the cylindrical peripheral wall of the burner main body 12 in order to set the fuel ejection direction to the burner main body 12 in a direction orthogonal to the longitudinal direction of the burner main body 12 has been exemplified. However, the fuel ejection direction to the burner main body 12 can be appropriately changed according to, for example, a mode in which the burner is installed in the furnace body.
For example, the fuel injection direction to the burner main body 12 may be set to a direction along the longitudinal direction of the burner main body 12. In this case, the nozzle tip 11 is attached to the cylinder end wall of the burner main body 12. A burner in which the fuel ejection direction to the burner main body 12 is set in a direction along the longitudinal direction of the burner main body 12,
For example, in the above-mentioned glass melting furnace, the burner is suitable for a so-called underport type in which the burner is installed so as to be inserted into a cylindrical wall below the air port 5.

(B) In the above embodiment, one circular plate is provided with a circular hole for the liquid fuel discharge hole 11o and a plurality of circular holes for the gas fuel discharge hole 11g. The case where the nozzle tip 11 is provided with a liquid fuel ejection hole 11o and a plurality of gas fuel ejection holes 11g is illustrated. Instead of this, for example, a liquid fuel injection nozzle provided with a liquid fuel ejection hole 11o and a plurality of gas fuel ejection nozzles provided with a gas fuel ejection hole 11g are connected to the liquid fuel ejection hole 11o.
May be installed in a predetermined arrangement form in which a plurality of gas fuel ejection holes 11g are located around the periphery of the fuel cell.

(C) In the above embodiment, the case where one liquid fuel ejection hole 11o is provided has been exemplified, but a plurality of liquid fuel ejection holes 11o may be provided. or,
The number of gas fuel ejection holes 11g provided side by side around the liquid fuel ejection holes 11o is not limited to eight as exemplified in the above embodiment, and can be changed as appropriate.

(D) The supply pressure of the gaseous fuel and the supply pressure of the liquid fuel are not limited to the values exemplified in the above embodiment, but the total combustion amount and the ratio of the combustion amount by the gas fuel to the total combustion amount. In any case, the total combustion amount is 3000 to 9000 k.
A burner having a range of W and a ratio of the amount of combustion by gas fuel to the total amount of combustion within a range of 1 to 30% is applied to the burner body 12.
The outer diameter D of the burner body ranges from 65 to 100 mm, the length L of the burner body ranges from 1000 to 2000 mm, and the gas fuel (13
It can be manufactured under the conditions that the supply pressure of A) is 0.098 MPa or less and the supply pressure of the liquid fuel (heavy oil A) is about 1.96 MPa.

(E) The gas fuel is not limited to the 13A city gas exemplified in the above embodiment, and various gas fuels other than 13A such as city gas and propane gas can be used. As the liquid fuel, various liquid fuels such as kerosene and the like can be used in addition to the heavy fuel oil A and heavy fuel oil C exemplified in the above embodiment.

(F) The burner according to the present invention can be applied to various heating furnaces other than the glass melting furnace exemplified in the above embodiment.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a burner according to an embodiment.

FIG. 2 is a cross-sectional view of the burner according to the embodiment.

FIG. 3 is a front view of a nozzle tip of the burner according to the embodiment;

FIG. 4 is a cross-sectional view of the nozzle tip of the burner according to the embodiment along the axis of the liquid fuel ejection hole.

FIG. 5 is a longitudinal sectional view of a glass melting furnace using a burner according to the embodiment.

FIG. 6 is a view as seen from an arrow II in FIG. 5;

FIG. 7 is a diagram showing an emissivity distribution in a longitudinal direction of a combustion flame.

FIG. 8 is a view showing a temperature distribution in a longitudinal direction of a combustion flame.

[Explanation of symbols]

 11g Gas fuel ejection hole 11o Liquid fuel ejection hole 12 Burner body 13 Liquid fuel path 14 Gas fuel path

Claims (4)

[Claims] 1. A liquid fuel ejection hole which brings a liquid fuel supplied in a pressurized state into an atomized state with ejection, and a liquid fuel ejection hole which is positioned around the liquid fuel ejection hole and is supplied from the liquid fuel ejection hole. A plurality of gas fuel ejection holes for ejecting gas fuel in a direction parallel or substantially parallel to the fuel ejection direction,
The liquid fuel combustion flame ejected from the liquid fuel ejection hole and burning as the main flame is supplemented by the gas fuel combustion flame ejected from the plurality of gas fuel ejection holes and burned as the supplementary flame. Burners for heating furnaces. 2. The burner for a heating furnace according to claim 1, wherein the total combustion amount including the combustion amount by the liquid fuel and the combustion amount by the gas fuel is 3000 kW or more. 3. The burner for a heating furnace according to claim 1, wherein the combustion amount by the gas fuel is 1 to 30% of the total combustion amount of the combustion amount by the liquid fuel and the combustion amount by the gas fuel. 4. A liquid fuel passage which guides liquid fuel to the liquid fuel ejection hole and a gas fuel passage which guides gas fuel to the plurality of gas fuel ejection holes are formed inside each of which has a columnar outer shape. 4. The heating furnace according to claim 1, wherein the burner main body provided with the flow path longitudinal direction along the column longitudinal direction is configured so that an outer diameter is in a range of 65 to 100 mm. 5. Burner.