JP4892379B2 - Fuel combustion device - Google Patents

Description

  The present invention relates to a fuel combustion apparatus. Specifically, the present invention relates to a fuel combustion apparatus such as a burner that injects and burns liquefied gas fuel.

Conventionally, a fuel combustion apparatus such as a burner that mixes a liquid fuel such as heavy oil and a spray medium such as steam or air, injects the liquid fuel in a mist state by the pressure of the spray medium, ignites it, and burns it is known. (For example, Patent Document 1).
According to this, since the liquid fuel is atomized and the surface area in contact with the combustion air is increased, efficient combustion is possible.
Such a fuel combustion apparatus is incorporated in, for example, a boiler or a heating furnace, and is used as a heat source device that generates steam used in a production process or steam for heating / hot water supply. A boiler, a heating furnace, and the like create steam by evaporating water using heat generated by combustion by a fuel combustion device such as a burner, for example.

  By the way, the fuel used for the fuel combustion apparatus has been mainly heavy oil, but recently, it has been changed to gas fuel from the viewpoint of exhaust gas cleaning. For the purpose of facilitating transportation and storage, examples of the liquefied liquefied fuel obtained by pressurizing and liquefying gas fuel include liquefied petroleum gas (LPG) and dimethyl ether (DME: Di-Methyl Ether). It is done. For example, since DME has handling properties such as being easily liquefied, it is expected to become a main fuel for boilers and heating furnaces in the future.

However, such liquefied gas fuel has a lower flame brightness than conventional liquid fuel such as heavy oil. For this reason, when a liquefied gas fuel is combusted using a conventional fuel combustion apparatus such as Patent Document 1, an orange bright flame such as heavy oil is not produced even when an operation with an extremely reduced amount of combustion air is performed. It does not emit and presents a blue non-luminous flame.
When such a fuel combustion apparatus is applied to, for example, a boiler, the amount of radiant heat transfer in the furnace of the boiler is reduced, so that the capacity is reduced depending on the design specifications of the boiler. As a result, the load on the boiler has to be reduced (for example, to about 60%). If the boiler capacity is not sufficient, conversion to liquefied gas fuel may be difficult.

Therefore, in order to solve such a problem, for example, Patent Document 2 discloses a substantially frustoconical hollow portion that is in communication with the discharge hole on the fuel discharge hole side of the burner tip and spreads in the fuel spraying direction. A burner in which the formed cylindrical member is disposed is disclosed.
In the burner described in Patent Document 2, the fuel discharged from the discharge hole is sprayed and burned by adjusting the diffusion state through a substantially frustoconical cavity and forming a pseudo incomplete combustion state. As a result, the brightness of the flame can be improved.
However, generally, the pressure of liquefied gas fuel is high, and the injection speed of liquefied gas fuel is faster than the injection speed of heavy oil or the like. For this reason, the liquefied gas fuel is not sufficiently entrained in the air, the flame formed in the vicinity of the burner injection hole becomes unstable, and stable combustion may not be expected.

In order to solve such a problem, for example, a method of causing liquefied gas fuel sprayed from a plurality of locations to collide with each other is conceivable.
According to such a method, the sprayed liquefied gas fuel particles cancel each other's momentum due to the collision, so that the speed of the liquefied gas fuel after the collision decreases. Stable combustion can be obtained by lowering the injection speed. In addition, by causing the liquefied gas fuels to collide with each other, the particles of the liquefied gas fuel are scattered and the surrounding air is easily trapped. Therefore, excellent combustion stability of the liquefied gas fuel can be realized.

JP-A-2005-257170 JP 2006-162095 A

  However, in the burner described in Patent Document 2 and the burner described in Patent Document 2 in which a mechanism for causing the liquefied gas fuel to collide with the burner is added, a pseudo incomplete combustion state occurs. There was a risk that the carbon monoxide (CO) concentration would increase.

  An object of the present invention is to provide a fuel combustion apparatus that solves the above-described problems and the like, has high flame brightness, excellent combustion stability, and low CO concentration in combustion exhaust gas.

  The fuel combustion apparatus of the present invention is a fuel combustion apparatus for burning liquefied gas fuel, a fuel spray tip for spraying the liquefied gas fuel, a fuel supply means for supplying the liquefied gas fuel to the fuel spray tip, The fuel spray tip includes first spray means and second spray means for spraying the liquefied gas fuel, and the first spray means includes a plurality of ejection portions for ejecting the liquefied gas fuel; A substantially cone-shaped hollow portion that communicates with the jet portion of the liquefied gas fuel and spreads in the spraying direction of the liquefied gas fuel, and the plurality of jet portions are provided in the hollow portion and jetted from the plurality of jet portions. The liquefied gas fuel collides with each other in the cavity, and is sprayed to the outside through the cavity. The second spraying means sprays the liquefied gas fuel without passing through the cavity. The first The liquefied gas fuel which is sprayed from the spray means and said second spray means, and forming a single flame is burned at the same time.

The first spraying means jets liquefied gas fuel from a plurality of jetting parts provided in the cavity. At this time, the liquefied gas fuel is injected in a sprayed state by boiling under reduced pressure, and the injected liquefied gas fuels collide with each other in the cavity.
The atomized liquefied gas fuel particles cancel each other's momentum by collision and diffuse in the substantially pyramid-shaped cavity, so that the speed of the liquefied gas fuel after the collision is reduced. Stable combustion can be obtained by the reduction in the injection speed. In addition, by causing the liquefied gas fuels to collide with each other, the particles of the liquefied gas fuel are scattered and the surrounding air is easily trapped. Therefore, excellent combustion stability of the liquefied gas fuel can be realized.

Here, the liquefied gas fuel ejected from the ejecting portion of the first spraying means is sprayed to the outside through the substantially conical cavity, and the diffusion state of the liquefied gas fuel is adjusted.
If the liquefied gas fuel whose diffusion state is adjusted is burned, a pseudo incomplete combustion state is formed, so that the brightness of the flame can be improved.
Further, since the liquefied gas fuel injected in the substantially conical back portion of the hollow portion is gradually depressurized toward the opening portion, vaporization and expansion due to the reduced pressure boiling of the liquefied gas fuel can be gently generated. . Accordingly, since the ejected liquefied gas fuel does not rapidly vaporize and expand at the open portion of the cavity, a stable flame can be formed.

On the other hand, the second spraying means sprays the liquefied gas fuel without passing through the cavity.
Therefore, when the liquefied gas fuel sprayed from the second spraying means is combusted, it is unlikely that sufficient air is supplied to the flame and an incomplete combustion state is formed, so the CO concentration in the combustion exhaust gas is reduced. Can be suppressed.

That is, when the liquefied gas fuel sprayed from the first spraying means is burned, the CO concentration in the combustion exhaust gas is increased, but the flame brightness and combustion stability are excellent. When the liquefied gas fuel sprayed from the second spraying means is burned, the brightness and combustion stability of the flame may be insufficient, but the CO concentration in the combustion exhaust gas can be kept low.
Since the fuel combustion apparatus of the present invention simultaneously burns the liquefied gas fuel sprayed from the first spray means and the second spray means to form one flame, the first spray means and the second spray means. (That is, a fuel combustion device in which a mechanism for causing liquefied gas fuel to collide with a conventional fuel combustion device or a fuel combustion device described in Patent Document 2 is added). The brightness and combustion stability of the flame can be improved while keeping the CO concentration inside low.

  In the present invention, the fuel combustion device includes an adjusting unit that adjusts a combustion amount of the liquefied gas fuel sprayed from the fuel spray tip, and the adjusting unit sprays the liquefied gas sprayed from the first spray unit. It is preferable that a first adjustment unit that adjusts the combustion amount of fuel and a second adjustment unit that adjusts the combustion amount of the liquefied gas fuel sprayed from the second spray unit.

According to such a configuration, the combustion amount by the first spraying means and the combustion amount by the second spraying means are adjusted separately by the first adjusting means and the second adjusting means.
Therefore, the ratio of the combustion amount by the first spraying means and the combustion amount by the second spraying means can be arbitrarily set, and the optimum balance between the brightness and combustion stability of the flame and the CO concentration in the combustion exhaust gas. The liquefied gas fuel can be burned under various conditions.

  In the present invention, the amount of combustion of the liquefied gas fuel sprayed from the first spraying means is 40% by mass with respect to the total amount of combustion of the liquefied gas fuel sprayed from the first spraying means and the second spraying means. It is preferable that it is 70 mass% or less.

According to such a configuration, the liquefied gas fuel can be burned under optimal conditions in which the brightness and combustion stability of the flame and the CO concentration in the combustion exhaust gas are balanced.
Here, when the ratio of the amount of combustion by the first spraying means to the total amount of combustion by the first spraying means and the second spraying means (hereinafter abbreviated as the combustion rate) is less than 40% by mass, Since luminance and combustion stability are lowered, it is not preferable. A combustion rate exceeding 70% by mass is not preferable because the CO concentration in the combustion exhaust gas increases.
The combustion rate is more preferably 45% by mass or more and 65% by mass or less, and further preferably 50% by mass or more and 60% by mass or less.

  In the present invention, a plurality of injection axes indicating directions in which the plurality of ejection portions of the first spraying means eject the liquefied gas fuel intersect each other in the cavity portion, and the substantially cone-shaped axis of the cavity portion is Preferably, it passes through the intersection of the plurality of injection axes.

According to such a configuration, the liquefied gas fuel ejected from each ejection portion into the cavity proceeds along each injection axis and collides with each other at the intersection of the injection axes.
Therefore, the collision of the liquefied gas fuel can be realized with a relatively simple configuration.
Further, since the hollow portion has a substantially conical shape in which the axis passes through the intersection of each injection axis, the air pressure inside the hollow portion gradually decreases from the back of the substantially conical shape toward the open portion, and in the open portion Furnace pressure.
Accordingly, since the ejected liquefied gas fuel does not rapidly vaporize and expand at the open portion of the cavity, a stable flame can be formed.
Of course, as described above, the cavity adjusts the diffusion state of the liquefied gas fuel to form a pseudo incomplete combustion state.

In the present invention, it is preferable that the plurality of injection axes intersect each other at an angle of 60 degrees to 120 degrees.
According to such a structure, the liquefied gas fuel injected from each jet part collides with each other at an angle of 60 degrees or more and 120 degrees or less. After collision, the liquefied gas fuels that collide with each other at this angle cancel the velocity in the direction along the line connecting the ejection parts, and are further decelerated and ejected in a direction perpendicular to the line connecting the ejection parts. .

Here, when the crossing angle of the injection axes of the ejection portions is smaller than 60 degrees, the liquefied gas fuels collide with each other at an angle smaller than 60 degrees. Then, at the time of a collision, the speed of the liquefied gas fuel in the direction orthogonal to the line connecting the ejection portions is too high, and thus the deceleration effect in this direction cannot be obtained.
On the other hand, when the crossing angle of the injection axes of the ejection portions is larger than 120 degrees, the liquefied gas fuels also collide with each other at an angle larger than 120 degrees. Then, after the collision, the velocity of the liquefied gas fuel in the direction orthogonal to the line connecting the ejection portions is insufficient, and the liquefied gas fuel easily collides with the inner wall of the cavity portion, so that atomization failure (drip) is likely to occur. .
On the other hand, when the liquefied gas fuels collide with each other at a collision angle of 60 degrees or more and 120 degrees or less as in the present invention, the speed of the liquefied gas fuel can be appropriately reduced.
Therefore, a more stable flame can be formed, and excellent combustion stability of the liquefied gas fuel can be realized.

In the present invention, it is preferable that the substantially conical shape of the cavity has an opening angle of 15 degrees to 30 degrees with respect to the axis of the cavity.
Here, when the opening angle is less than 15 degrees, the liquefied gas fuel interferes with the inner side surface of the cavity and the atomization failure is likely to occur. On the other hand, when the opening angle exceeds 30 degrees, the liquefied gas fuel cannot be gently vaporized / expanded.
On the other hand, when the opening angle is set to 15 degrees or more and 30 degrees or less, the liquefied gas fuel scattered by the collision is less likely to interfere with the inner surface of the cavity. Moreover, the atmospheric pressure inside the cavity can be gradually reduced from the substantially conical back to the open part. Therefore, a more stable flame can be formed, and excellent combustion stability of the liquefied gas fuel can be realized.
Further, if the opening angle is 15 degrees or more and 30 degrees or less, the diffusion state of the liquefied gas fuel can be appropriately adjusted, and the brightness of the flame can be improved.

In the present invention, the ejection portion is a hole having a substantially circular cross section, and the number N of the holes, the hole diameter Dn of the holes, and the axial length L of the cavity are expressed by the following equations: It is preferable to satisfy (1).
{L ² / (Dn ² × N)} ≧ 130 (1)
According to such a configuration, the fuel spray tip has dimensions such that the number N of the holes, the hole diameter Dn of the holes, and the length L along the axis of the cavity always satisfy the above formula. Thus, by setting the length L of the cavity to a relatively appropriate dimension with respect to the injection scale of the liquefied gas fuel represented by the number N of holes and the hole diameter Dn of the holes, the cavity In addition, it is possible to achieve an internal pressure change characteristic for the liquefied gas fuel to be gradually vaporized and expanded. Therefore, the fuel spray tip of the present invention can form a more stable flame, and can realize excellent combustion stability of the liquefied gas fuel.
Further, according to such a configuration, it is possible to appropriately adjust the diffusion state of the liquefied gas fuel and improve the flame brightness.

  In the present invention, the fuel spray tip includes spray medium supply means for supplying a spray medium, and the second spray means mixes the liquefied gas fuel and the spray medium, and mixes the liquefied gas fuel and the spray medium. A mixture ejection section for ejecting the mixture, a spray medium supply passage for supplying the spray medium to the mixture ejection section, and a fuel supply passage for supplying the liquefied gas fuel to the mixture ejection section. Is preferred.

According to such a configuration, the spray medium and the liquefied gas fuel can be mixed and the atomized liquefied gas fuel can be ejected to the outside in a combustible state in the mixture ejection portion.
Here, such second spraying means is also provided in the fuel spraying tip of the conventional fuel combustion apparatus. Therefore, the fuel spray tip of the present invention can be easily obtained by providing the first spray means on the conventional fuel spray tip.

  In the present invention, a plurality of the mixture ejection portions of the second spraying means are provided at substantially equal positions on the circumference around the axis of the cavity of the first spraying means, and surround the cavity. It is preferable that

According to such a configuration, the liquefied gas fuel is sprayed from the second spraying means so as to surround the liquefied gas fuel sprayed by the first spraying means.
Therefore, if the liquefied fuel gas sprayed from the first spraying means or the second spraying means is combusted, the liquefied gas fuel sprayed from the first spraying means and the second spraying means is combusted simultaneously, and one flame is burned. Can be formed.
In addition, since the mixture ejection portion is provided at a substantially equal position on the circumference centering on the axis of the cavity portion, the brightness and the CO concentration in the combustion exhaust gas do not vary depending on the position of the flame. Operability similar to that of the combustion apparatus can be ensured.

  In the present invention, the plurality of ejection portions of the first spraying means are provided at a plurality of substantially equal positions on a circumference around the axis of the hollow portion, and the plurality of ejection portions of the first spraying means. And any one of the plurality of mixture ejection portions of the second spraying means are not located on the same side with respect to the axis of the cavity on one plane including the axis of the cavity. Is preferred.

According to such a structure, an ejection part and a mixture ejection part do not adjoin too much, and generation | occurrence | production of combustion failure can be prevented.
When the jet part and the mixture jet part are provided close to each other, when the liquefied gas fuel is burned, the flow of the liquefied gas fuel jetted from the jet part and the flow of the liquefied gas fuel jetted from the mixture jet part Interfere with each other, resulting in poor combustion.
If the ejection part and the mixture ejection part are provided evenly with respect to the axis of the cavity and are not located on the same side on one plane including the axis, the distance between the ejection part and the mixture ejection part Therefore, the interference of the flow of the liquefied gas fuel and the occurrence of poor combustion can be prevented.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Configuration of fuel combustion device]
FIG. 1 is a diagram showing a schematic configuration of a fuel combustion apparatus 1 of the present embodiment.
As shown in FIG. 1, the fuel combustion apparatus 1 includes a burner 3 having a fuel spray tip 2, fuel supply means 5 for supplying liquefied gas fuel 4 to the burner 3, and spray for supplying a spray medium 6 to the burner 3. Medium supply means 7.

The fuel supply means 5 is provided with a fuel storage tank 51 for storing DME as the liquefied gas fuel 4, a pipe 52 connecting the burner 3 and the fuel storage tank 51, and pressurization of the liquefied gas fuel 4 provided in the pipe 52. And a flow rate adjusting valve 54 that adjusts the flow rate of the liquefied gas fuel 4 provided in a portion between the burner 3 and the pressurizing pump 53 of the pipe 52.
The spray medium supply means 7 includes a spray medium storage tank 71 that stores compressed air that is the spray medium 6, a pipe 72 that connects the burner 3 and the spray medium storage tank 71, and a flow rate of the spray medium 6 provided in the pipe 72. A flow rate adjusting valve 73 to be adjusted.

[Burner configuration]
FIG. 2 shows a partial cross-sectional view of the burner 3. In the following description, the right side of FIG. 2 is the front end side, and the left side is the rear end side.
As shown in FIG. 2, the burner 3 includes a burner body 31, a handle part 32 attached to the rear end side of the burner body 31, and a spray combustion part 33 attached to the front end side of the burner body 31.

The burner body 31 includes a gun body 311, a fuel supply hole 312 provided in a front side surface (lower right in FIG. 2) of the gun body 311, and a rear end side surface (upper left in FIG. 2). And a spray medium supply hole 313 provided on the surface.
A pipe 55 is screwed into the fuel supply hole 312, and a pipe 52 of the fuel supply means 5 is connected to the pipe 55 by a union 56.
Further, a pipe 74 is screwed into the spray medium supply hole 313, and a pipe 72 of the spray medium supply means 7 is connected to the pipe 74 by a union 75.

  Inside the gun body 311, the rear end side of the portion where the fuel supply hole 312 is provided and the front end side of the portion where the spray medium supply hole 313 is provided, that is, the middle of the supply holes 312 and 313. Is provided with a substantially cylindrical sleeve 314. The sleeve 314 is formed so that the side surface on the front end side is in contact with the inner wall of the gun body 311, and includes a tapered portion 314 </ b> A whose outer diameter decreases in a substantially cylindrical shape toward the rear end side. The sleeve 314 has a constant inner diameter, and a circular hole 314B is formed along the central axis of the sleeve 314.

  A packing 315 is provided between the outer wall of the tapered portion 314 </ b> A and the inner wall of the gun body 311. The packing 315 is urged toward the distal end side through a packing presser 316 that is screwed onto the outer wall of the sleeve 314, and seals the gap between the outer wall of the sleeve 314 and the inner wall of the gun body 311.

The handle portion 32 includes a plug 322 that is screwed into the gun body 311 via the packing 321, a substantially cylindrical handle pin 323 that is fitted to the plug 322, and one end at the rear end portion 323 </ b> A of the handle pin 323. The other end is made of a linear metal attached to the plug 322 and includes a handle 324 formed in a spiral shape around the handle pin 323.
By grasping and operating the handle 324, the position and direction of the burner 3 can be changed.

The spray combustion unit 33 has a long cylindrical outer nozzle 331 that is welded so as to be in contact with the inner wall of the gun body 311, and a long cylindrical shape that is inserted and welded into the circular hole 314 </ b> B of the sleeve 314 and coaxial with the outer nozzle 331. A certain inner nozzle 332, a substantially cylindrical nozzle body 333 welded so as to be in contact with the inner wall of the tip of the outer nozzle 331, and a fuel in close contact with the tip of the inner nozzle 332 and the tip of the nozzle body 333 The spray tip 2 is provided with a cap 334 that is screwed into the outer wall of the tip of the nozzle body 333 and biases the fuel spray tip 2 toward the inner nozzle 332 and the nozzle body 333 by the tightening force thereof.
A gap 335 having an annular cross section is formed between the inner wall of the outer nozzle 331 and the outer wall of the inner nozzle 332, and is continuous with the gap 335 between the inner wall of the nozzle body 333 and the outer wall of the inner nozzle 332. A gap 336 having an annular cross section is formed. Since the inner nozzle 332 has a cylindrical shape, a circular hole 332A is formed along the central axis thereof.

[Configuration of fuel spray tip]
3 is a view showing the fuel spray tip 2 viewed from the front end side in FIG. 2, FIG. 4 is a sectional view taken along line IV-IV in FIG. 3, and FIG. 5 is a sectional view taken along line VV in FIG.
As shown in FIGS. 3, 4, and 5, the fuel spray tip 2 is a substantially cylindrical member, and includes a first spray unit 21 and a second spray unit 22 that spray liquefied gas fuel, and a liquefied spray. Adjusting means 23 for adjusting the combustion amount of the gas fuel 4.
The adjusting means 23 adjusts the combustion amount of the liquefied gas fuel 4 sprayed from the first spraying means 21 and the first adjusting means 231 that adjusts the combustion amount of the liquefied gas fuel 4 sprayed from the first spraying means 21. Second adjusting means 232.

(1) Configuration of First Spraying Unit As shown in FIGS. 3 and 4, the first spraying unit 21 is connected to a plurality of jetting portions 211 that jet the liquefied gas fuel 4 and a plurality of jetting portions 211, and is a liquefied gas fuel. 4 is provided with a substantially cone-shaped cavity 212 that spreads in the spraying direction, and a fuel supply passage 213 that supplies the liquefied gas fuel 4 to the ejection portion 211.

The ejection part 211 is a hole part 211 </ b> A having a substantially circular cross section provided on the rear end side in the cavity part 212. Four ejection portions 211 are provided at substantially equal positions on the circumference around the axis 212 </ b> A of the cavity portion 212. That is, one ejection portion 211 is provided at intervals of 90 degrees with the axis 212A as the center.
The cavity portion 212 is provided at a substantially central portion on the front end side of the fuel spray tip 2 and has a substantially truncated cone shape with a smaller diameter toward the rear end side. The opening angle X of the hollow portion 212 with respect to the substantially frustoconical axis is 15 degrees or more and 30 degrees or less.

The fuel supply passage 213 is a substantially cylindrical hole provided near the side surface of the fuel spray tip 2 and substantially parallel to the axis of the fuel spray tip 2.
The rear end of the fuel supply passage 213 communicates with the gap 336 of the nozzle body 333, and the end of the fuel supply passage 213 communicates with the ejection portion 211 (hole 211A). . The hole 211 </ b> A is formed narrower than the fuel supply passage 213 in order to control the supply amount of the liquefied gas fuel 4. That is, the hole 211A also functions as the first adjusting unit 231.

As shown in FIG. 4, a plurality (four) of injection shafts 211 </ b> B indicating directions in which a plurality (four) of the ejection portions 211 eject the liquefied gas fuel 4 intersect each other in the cavity 212, and the cavity 212 The substantially truncated cone-shaped shaft 212A passes through the intersection 211C of the plurality of injection shafts 211B.
Here, the angle Y formed by the plurality of injection shafts 211B is not less than 60 degrees and not more than 120 degrees.
Further, the number N (4 in the present embodiment) of the ejection portions 211, the hole diameter Dn of the ejection portions 211, and the length L of the cavity portion 212 in the axis 212A direction satisfy the following expression (1).
{L ² / (Dn ² × N)} ≧ 130 (1)

(2) Configuration of Second Spraying Unit As shown in FIGS. 3 and 5, the second spraying unit 22 mixes the liquefied gas fuel 4 and the spray medium 6 and mixes the liquefied gas fuel 4 and the spray medium 6. A mixture ejection part 221 that ejects, a spray medium supply passage 222 that supplies the spray medium 6 to the mixture ejection part 221, and a fuel supply path 223 that supplies the liquefied gas fuel 4 to the mixture ejection part 221 are provided.

Four mixture ejection portions 221 are provided at substantially equal positions on the circumference around the axis 212 </ b> A of the cavity portion 212 of the first spraying means 21, and surround the cavity portion 212. That is, the mixture ejection part 221 is provided at intervals of 90 degrees with the axis 212A as the center.
The spray medium supply passage 222 is a substantially cylindrical hole provided in the center of the fuel spray tip 2 in parallel with the axis of the fuel spray tip 2.
The rear end side end of the spray medium supply passage 222 communicates with the circular hole 332 </ b> A of the inner nozzle 332, and the front end side end of the spray medium supply passage 222 communicates with the mixture ejection portion 221.

The fuel supply passage 223 has a substantially cylindrical hole 223A and a hole 223B having a diameter smaller than that of the hole 223A.
The hole 223 </ b> A is provided near the side surface of the fuel spray tip 2 and substantially parallel to the axis of the fuel spray tip 2. The hole 223B has an opening at the end on the tip side of the hole 223A and the side surface of the mixture ejection part 221, and allows the hole 223A and the mixture ejection part 221 to communicate with each other.
The end of the hole 223A on the tip side communicates with a hole 223B that is thinner than the hole 223A. The hole 223 </ b> B controls the supply amount of the spray medium 6 and functions as the second adjusting unit 232.

As shown in FIG. 3, the fuel supply passages 213 and the fuel supply passages 223 are alternately provided at intervals of 45 degrees around the shaft 212 </ b> A of the cavity portion 212.
For this reason, the ejection part 211 and the mixture ejection part 221 are also provided alternately at intervals of 45 degrees around the axis 212A of the cavity part 212.
Therefore, any one of the plurality of ejection portions 211 of the first spraying means 21 and any one of the plurality of mixture ejection portions 221 of the second spraying means 22 are the cavity portions 212 on one plane including the shaft 212A of the cavity portion 212. Are not located on the same side with respect to the axis 212A.

[Operation of fuel combustion system]
An example of the operation of the fuel combustion apparatus 1 of the present invention having the above configuration will be described with reference to FIGS.

As shown in FIG. 1, in the fuel combustion apparatus 1, DME which is the liquefied gas fuel 4 is sent out from the fuel storage tank 51 to the pressurizing pump 53 via a pipe 52A. The liquefied gas fuel 4 pressurized by the pressure pump 53 is introduced into the fuel supply hole 312 of the burner 3 through the pipe 52B.
The flow rate of the liquefied gas fuel 4 to the burner 3 is adjusted by a flow rate adjusting valve 54.
On the other hand, the air as the spray medium 6 is introduced from the spray medium storage tank 71 storing air into the spray medium supply hole 313 of the burner 3 through the pipe 72.
The flow rate of the spray medium 6 to the burner 3 is adjusted by a flow rate adjusting valve 73.

As shown in FIG. 2, the liquefied gas fuel 4 introduced from the fuel supply hole 312 in the burner 3 flows into the gun body 311. Thereafter, the liquefied gas fuel 4 passes through the gap 335 and the gap 336 of the spray combustion unit 33 and flows into the fuel supply passage 213 and the fuel supply passage 223 of the fuel spray tip 2.
On the other hand, the air as the spray medium 6 flows into the gun body 311 through the spray medium supply hole 313. Thereafter, the gas passes through the circular hole 314 </ b> B of the sleeve 314 and the circular hole 332 </ b> A of the inner nozzle 332 in order, and flows into the spray medium supply passage 222 of the fuel spray tip 2.

As shown in FIG. 4, in the fuel spray tip 2, the liquefied gas fuel 4 that has flowed from the fuel supply passage 213 is ejected into the cavity 212 via the ejection portion 211.
The liquefied gas fuel 4 ejected from the ejection part 211 into the cavity part 212 travels along each injection axis 211B and collides with each other at the intersection 211C of the injection axis 211B. Since the particles of the liquefied gas fuel 4 cancel each other's momentum due to the collision, the speed of the liquefied gas fuel 4 after the collision is reduced.
The liquefied gas fuel 4 injected and collided at the back part of the substantially truncated cone shape of the cavity part 212 is gradually depressurized toward the opening part of the cavity part 212 and the diffusion state is adjusted and sprayed to the outside. Is done.

As shown in FIG. 5, in the fuel spray tip 2, the spray medium 6 that has flowed in from the spray medium supply passage 222 is ejected to the mixture ejection section 221.
In addition, the liquefied gas fuel 4 that has flowed in from the fuel supply passage 223 passes through the hole 223A and the hole 223B and is jetted to the side surface of the mixture jet part 221. Here, it is mixed with the spray medium 6 at the mixture jetting part 221 and sprayed to the outside together with the spray medium 6.

In this way, the liquefied gas fuel sprayed from the ejection part 211 and the mixture ejection part 221 of the fuel spray tip 2 is ignited to start the combustion of the liquefied gas fuel.
The liquefied gas fuel 4 sprayed from the jetting part 211 of the first spraying means 21 and the mixture jetting part 221 of the second spraying means 22 is simultaneously burned to form one flame.

At this time, the amount of combustion of the liquefied gas fuel 4 sprayed from the first spraying means 21 is adjusted by adjusting the diameter of the hole 211A which is the first adjusting means 231. Similarly, the amount of combustion of the liquefied gas fuel 4 sprayed from the second spraying means 22 is adjusted by adjusting the diameter of the hole 223 </ b> B that is the second adjusting means 232.
Note that the combustion amount of the liquefied gas fuel 4 sprayed from the first spraying means 21 is 40 mass% or more to 70% by mass with respect to the total combustion amount of the liquefied gas fuel 4 sprayed from the first spraying means 21 and the second spraying means 22. It is preferable to adjust so that it may become mass% or less.

[Effect of the embodiment]
According to the above-described embodiment, the following effects can be achieved.

  In the first spraying means 21, the liquefied gas fuel 4 ejected from the ejection part 211 is injected in a sprayed state by boiling under reduced pressure and collides with each other in the cavity 212. Since the particles of the liquefied gas fuel 4 cancel each other's momentum due to the collision, the speed of the liquefied gas fuel after the collision is reduced. Stable combustion can be obtained by the reduction in the injection speed.

Further, in the first spraying means 21, since the liquefied gas fuel whose diffusion state is adjusted by the cavity 212 is burned, a pseudo incomplete combustion state is formed, and the brightness of the flame can be improved.
Since the liquefied gas fuel 4 injected at the back part of the substantially truncated cone shape of the cavity 212 is gradually depressurized toward the open part, the liquefied gas fuel 4 is gently caused to vaporize and expand due to reduced-pressure boiling. Can do. Therefore, since the ejected liquefied gas fuel 4 does not rapidly vaporize and expand at the opening portion of the cavity portion 212, a stable flame can be formed.

  In the 2nd spraying means 22, since the liquefied gas fuel 4 is sprayed without passing through the cavity part 212, favorable mixing with combustion air is obtained and the CO concentration in the combustion exhaust gas can be kept low.

That is, when the liquefied gas fuel 4 sprayed from the first spraying means 21 is burned, the CO concentration in the combustion exhaust gas is increased, but the flame brightness and combustion stability are excellent. When the liquefied gas fuel 4 sprayed from the second spraying means 22 is combusted, the brightness and combustion stability of the flame may be insufficient, but due to the effect of burning CO generated by the combustion by the first spraying means 21, The CO concentration as a whole flame can be kept low.
Since the fuel combustion apparatus 1 of the present invention burns the liquefied gas fuel 4 sprayed from the first spray means 21 and the second spray means 22 at the same time to form one flame, the first spray means 21. Or the second spraying means 22 (that is, the liquefied gas fuel is caused to collide with the conventional fuel combustion apparatus as described in Patent Document 1 or the fuel combustion apparatus described in Patent Document 2) Compared to a fuel combustion apparatus to which a mechanism is added), it is possible to improve the brightness of the flame and the combustion stability while suppressing the CO concentration in the combustion exhaust gas low.

  The amount of combustion by the first spraying means 21 and the amount of combustion by the second spraying means 22 can be adjusted separately by the first adjusting means 231 and the second adjusting means 232, respectively. The ratio of the combustion amount by the spraying means 22 can be arbitrarily set, and the liquefied gas fuel 4 is burned under optimum conditions in which the brightness and combustion stability of the flame and the CO concentration in the combustion exhaust gas are balanced. Can do.

The collision of the liquefied gas fuel 4 is realized by a relatively simple configuration in which the plurality of injection shafts 211B indicating the directions in which the plurality of ejection portions 211 eject the liquefied gas fuel 4 are intersected with each other in the cavity 212. Can do.
Since the cavity 212 has a substantially truncated cone shape in which the shaft 212A passes through the intersections of the respective injection axes 211B, the air pressure inside the cavity 212 gradually decreases from the inner part of the substantially truncated cone shape toward the open portion. In the open part, the furnace pressure is reached.
Therefore, since the ejected liquefied gas fuel 4 does not rapidly vaporize and expand at the opening portion of the cavity portion 212, a stable flame can be formed.

  Since the first spraying means 21 causes the liquefied gas fuels 4 to collide with each other at a collision angle of 60 degrees or more and 120 degrees or less, the speed of the liquefied gas fuel 4 can be appropriately reduced. Therefore, a more stable flame can be formed, and excellent combustion stability of the liquefied gas fuel 4 can be realized.

  Since the opening angle with respect to the axis of the cavity 212 is not less than 15 degrees and not more than 30 degrees, the liquefied gas fuel 4 scattered by the collision is less likely to interfere with the inner surface of the cavity 212, and the air pressure inside the cavity 212 is substantially frustoconical. It can be gradually lowered from the back to the opening. Therefore, a more stable flame can be formed, and excellent combustion stability of the liquefied gas fuel can be realized. In addition, it is possible to appropriately adjust the diffusion state of the liquefied gas fuel and improve the luminance of the flame.

  Since the number N of the hole portions 211A, the hole diameter Dn of the hole portion 211A, and the length L of the cavity portion 212 in the axis 212A direction satisfy the above-described formula (1), the cavity portion 212 of the liquefied gas fuel 4 It is possible to achieve an internal atmospheric pressure change characteristic for the gradual vaporization / expansion. Therefore, the fuel spray tip 2 of the present invention can form a more stable flame, and can realize the excellent combustion stability of the liquefied gas fuel 4. In addition, the diffusion state of the liquefied gas fuel 4 can be appropriately adjusted to improve the flame brightness.

  Since the liquefied gas fuel 4 is sprayed together with the spray medium 6 in the second spraying means 22, incomplete combustion can be prevented and the CO concentration in the combustion exhaust gas can be kept low.

  In the mixture spraying part 221 of the second spraying means 22, the spray medium 6 and the liquefied gas fuel 4 can be mixed, and the atomized liquefied gas fuel 4 can be jetted to the outside in a combustible state. Here, the second spray means 22 is also provided in the fuel spray tip 2 of the conventional fuel combustion apparatus 1. Therefore, the fuel combustion apparatus 1 of the present invention can be easily obtained by replacing the conventional fuel spray tip 2 with the fuel spray tip 2 incorporating both the first spray means 21 and the second spray means 22.

Since the liquefied gas fuel 4 is sprayed from the second spray means 22 so as to surround the liquefied gas fuel 4 sprayed by the first spray means 21, the liquefaction sprayed from the first spray means 21 and the second spray means 22. The gas fuel 4 can be burned at the same time to form one flame.
Moreover, since the mixture ejection part 221 is provided at a substantially equal position on the circumference centering on the axis 212A of the cavity part 212, the brightness and the CO concentration in the combustion exhaust gas do not vary depending on the position of the flame, The same operability as that of the conventional fuel combustion apparatus 1 can be ensured.

  One of the plurality of ejection portions 211 of the first spraying means 21 and one of the plurality of mixture ejection portions 221 of the second spraying means 22 are the axis of the cavity portion 212 on one plane including the axis 212A of the cavity portion 212. Since it is not located on the same side with respect to 212A, a distance is taken between the jetting part 211 and the mixture jetting part 221 to prevent the interference of the flow of the liquefied gas fuel 4 and the occurrence of poor combustion. be able to.

[Modification]
It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

In the present invention, the liquefied gas fuel is DME, but is not limited thereto.
For example, diethyl ether (DEE), liquefied petroleum gas (LPG), or the like may be used.
Even in this case, the same excellent effects as those of the above-described embodiment can be obtained.

In the present invention, the spray medium 6 is air, but is not limited thereto.
For example, the spray medium 6 may be steam or combustible gas.
Even in this case, the liquefied gas fuel 4 can be atomized in the mixture ejection portion 221 and ejected to the outside in a combustible state.

In this embodiment, although the fuel spray tip 2 illustrated the structure provided with the 1st adjustment means 231 and the 2nd adjustment means 232, it is not limited to this.
For example, the burner body 31 and the spray combustion unit 33 are configured to supply two pipes for supplying the liquefied gas fuel 4 to the fuel supply path 213 and the fuel supply path 223, respectively, and the flow rates of the liquefied gas fuel 4 in the two pipes. It is good also as a structure provided with two valves to adjust.
Even in this case, since the two valves act as the first adjusting means 231 and the second adjusting means 232, the ratio of the combustion amount by the first spraying means 21 and the combustion amount by the second spraying means 22 is arbitrarily set. Therefore, the liquefied gas fuel 4 can be burned under optimum conditions in which the brightness and combustion stability of the flame and the CO concentration in the combustion exhaust gas are balanced.

  In addition, the specific structure and shape in the implementation of the present invention may be other structures as long as the object of the present invention can be achieved.

  The present invention will be described in more detail with reference to examples and comparative examples. In addition, this invention is not restrict | limited to the description content of these Examples at all.

The DME that is the liquefied gas fuel 4 was combusted using the fuel combustion apparatus 1 of the above-described embodiment, using the spray medium 6 as air.
At this time, the adjusting means 23 changes the ratio (combustion amount rate) of the combustion amount by the first spraying means 21 to the total combustion amount by the first spraying means 21 and the second spraying means 22, and the combustion at each combustion amount rate. The CO concentration in the exhaust gas, the temperature of the combustion exhaust gas, and the presence or absence of a bright flame were evaluated.
The total amount of combustion by the first spraying means 21 and the second spraying means 22 was 280 kg / h. This corresponds to about 50% of the maximum combustion amount of the fuel combustion apparatus 1.
The combustion supply pressure is 0.5 MPaG or more and 1.4 MPaG or less.
The hole diameter Dn of the hole 211A of the ejection part 211 and the hole diameter of the mixture ejection part 221 are 0.5 mm or more and 0.9 mm or less.
The evaluation results are shown in Table 1, and the evaluation criteria are shown in Table 2. In addition, the presence or absence of the bright flame was confirmed by visually checking the color of the flame, and the blue color was evaluated as x, the slightly blue color as △, the slightly red color as ◯, and the red color as ◎.

From Table 1, it can be seen that the combustion rate of 35%, 50%, and 65% are the optimum conditions in which the luminance of the flame and the CO concentration in the combustion exhaust gas are balanced.
On the other hand, when the combustion rate is 75% or 100%, the CO concentration in the combustion exhaust gas is high. Further, when the combustion rate is 0% or 25%, the brightness of the flame decreases.

  The present invention can be used as a fuel combustion apparatus such as a burner that injects and burns liquefied gas fuel.

The figure which shows schematic structure of the fuel combustion apparatus which concerns on embodiment of this invention. The fragmentary sectional view of the burner of the fuel combustion apparatus concerning the embodiment of the present invention. The figure which looked at the fuel spray tip concerning the embodiment of the present invention from the tip side. IV-IV sectional drawing of FIG. VV sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel combustion apparatus 2 Fuel spray tip 3 Burner 4 Liquefied gas fuel 5 Fuel supply means 6 Spray medium 7 Spray medium supply means 21 1st spray means 22 2nd spray means 23 Adjustment means 211 Jetting part 211B Injection shaft 211C Crossing point 212 Cavity part 212A Axis 222 Spray medium supply passage 223 Fuel supply passage 231 First adjustment means 232 Second adjustment means

Claims (10)

A fuel combustion apparatus for burning liquefied gas fuel,
A fuel spray tip for spraying the liquefied gas fuel;
Fuel supply means for supplying the liquefied gas fuel to the fuel spray tip,
The fuel spray tip comprises first spray means and second spray means for spraying the liquefied gas fuel,
The first spraying means includes
A plurality of ejection portions for ejecting the liquefied gas fuel;
A substantially cone-shaped cavity that communicates with the plurality of jets and spreads in the direction in which the liquefied gas fuel is sprayed;
The plurality of ejection portions are provided in the cavity portion,
The liquefied gas fuel ejected from the plurality of ejection parts collides with each other in the cavity, and is then sprayed to the outside through the cavity.
The second spraying means sprays the liquefied gas fuel without passing through the cavity,
The liquefied gas fuel sprayed from the first spraying means and the second spraying means is combusted simultaneously to form one flame. The fuel combustion apparatus according to claim 1,
Adjusting means for adjusting the amount of combustion of the liquefied gas fuel sprayed from the fuel spray tip;
The adjusting means includes
First adjusting means for adjusting a combustion amount of the liquefied gas fuel sprayed from the first spraying means;
And a second adjusting means for adjusting a combustion amount of the liquefied gas fuel sprayed from the second spraying means. The fuel combustion apparatus according to claim 1 or 2, wherein
The combustion amount of the liquefied gas fuel sprayed from the first spraying means is 40 mass% or more and 70 mass% with respect to the total combustion amount of the liquefied gas fuel sprayed from the first spray means and the second spray means. A fuel combustion apparatus characterized by the following. A fuel combustion apparatus according to any one of claims 1 to 3,
A plurality of injection axes indicating directions in which the plurality of ejection portions of the first spraying means eject the liquefied gas fuel intersect each other in the cavity portion,
The substantially conical shape axis of the hollow portion passes through an intersection of the plurality of injection axes. The fuel combustion apparatus according to claim 4, wherein
The plurality of injection shafts intersect each other at an angle of 60 degrees or more and 120 degrees or less. A fuel combustion apparatus according to any one of claims 1 to 5,
The substantially conical shape of the hollow portion has an opening angle of 15 degrees to 30 degrees with respect to the axis of the hollow portion. A fuel combustion apparatus according to any one of claims 1 to 6,
The ejection part is a hole having a substantially circular cross section,
The number N of the holes, the hole diameter Dn of the holes, and the length L in the axial direction of the cavity satisfy the following formula (1).
{L ² / (Dn ² × N)} ≧ 130 (1) A fuel combustion apparatus according to any one of claims 1 to 7,
A spray medium supply means for supplying a spray medium to the fuel spray tip;
The second spraying means includes
A mixture jetting unit for mixing the liquefied gas fuel and the spray medium and jetting a mixture of the liquefied gas fuel and the spray medium;
A spray medium supply passage for supplying the spray medium to the mixture ejection portion;
And a fuel supply passage for supplying the liquefied gas fuel to the mixture ejection portion. The fuel combustion apparatus according to claim 8, wherein
The mixture ejection part of the second spraying means is
A plurality of substantially uniform positions on the circumference around the axis of the hollow portion of the first spray means;
A fuel combustion apparatus characterized by surrounding the cavity. The fuel combustion apparatus according to claim 9, wherein
The plurality of ejection portions of the first spraying means are provided in a plurality at substantially equal positions on the circumference around the axis of the cavity portion,
One of the plurality of ejection portions of the first spraying means and one of the plurality of mixture ejection portions of the second spraying means are arranged on an axis of the cavity portion on one plane including the axis of the cavity portion. A fuel combustion device characterized by not being located on the same side.

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