JP6552976B2 - Burner, boiler equipped with the same, and ship equipped with the same - Google Patents

Description

  The present invention relates to a burner capable of co-firing fuel oil or fuel gas with hydrogen, a boiler equipped with the burner, and a ship equipped with the burner.

Marine boilers that drive the main ship of the ship are operated using hydrocarbon fuel such as heavy oil and LNG.
Due to the recent tightening of exhaust gas regulations, fuel conversion to expensive low-sulfur heavy oil and conversion to high-performance desulfurization equipment are required when using heavy oil containing a large amount of sulfur, but an increase in running costs is expected. Ru. In addition, hydrocarbon fuel emits combustion gas containing carbon dioxide, which may cause global warming.
On the other hand, it has been studied to suppress the formation of sulfur oxides and reduce carbon dioxide emissions by replacing one of heavy oil or LNG with hydrogen.
A burner for co-firing LPG, which is a hydrocarbon fuel, and hydrogen is disclosed in Patent Document 1 below.

Japanese Utility Model Publication No. 60-42247

  However, hydrogen does not contain carbon in the fuel, so its radiation characteristics differ greatly from heavy oil and LNG. For this reason, although the fall of furnace heat absorption amount becomes a problem, in the said patent document 1, this point is not considered.

  Further, a structure capable of obtaining performance equivalent to that of heavy oil / LNG fired boiler during hydrogen combustion is required. Since hydrogen combustion has inferior radiation characteristics compared to hydrocarbon fuels, the pitch of the heat transfer tubes is increased to increase the number of heat transfer tubes, or fins are installed in the heat transfer tubes to increase the heat transfer area. It is conceivable. However, such measures are difficult from the viewpoint of blocking the combustion gas flow path due to adhesion of solid substances contained in the combustion exhaust gas of heavy oil and LNG. Therefore, significant structural changes can not be made from heavy oil and LNG fired boilers.

From the above, there is a problem that the boiler performance equivalent to that at the time of heavy oil and LNG burning can not be obtained by the decrease of the amount of radiant heat transfer at the time of hydrogen combustion.
In addition, since the amount of radiant heat transfer during hydrogen combustion decreases, the temperature at the furnace outlet rises without sufficient heat absorption in the furnace, so it is necessary to review the materials for the current evaporator and superheater. There is.

  The present invention has been made in view of such circumstances, and a burner capable of co-firing fuel oil or fuel gas and hydrogen without significant change in the boiler structure, a boiler provided with the burner, and the same Aims to provide ships equipped with

In order to solve the said subject, the burner of this invention, the boiler provided with this, and the ship provided with this employ | adopt the following means.
That is, in the burner according to the present invention, a plurality of fuel injection holes for injecting fuel oil and a plurality of hydrogens for injecting hydrogen from the periphery of each of the fuel injection holes and forming a hydrogen region around each of the fuel injection holes Injection holes and an air supply unit for supplying combustion air from around each of the hydrogen injection holes, and fuel oil injected from each of the fuel injection holes burns in the hydrogen region where oxygen is insufficient It is characterized by

  Since hydrogen is injected around the fuel injection hole, a hydrogen region formed by hydrogen injection exists around the fuel injection hole. For this reason, the fuel oil (for example, heavy oil) injected from the fuel injection hole is injected to the hydrogen area which exists around the fuel injection hole, before meeting with the air which exists further in the perimeter. In this hydrogen region, hydrogen burns faster than fuel oil, so hydrogen combustion takes precedence over fuel oil combustion. Therefore, in the hydrogen region, oxygen is consumed by hydrogen combustion, so the region becomes oxygen deficient. And, in the fuel oil, the combustion under the lack of oxygen is stably carried out in the state where hydrogen is the auxiliary fuel. As a result, the fuel oil starts to combust under a lack of oxygen, so that soot generation actively proceeds and the particle radiation rate increases. Therefore, even if hydrogen is mixed as a fuel, it is possible to prevent the radiation heat transfer performance in the furnace from being lowered and to secure a sufficient furnace heat absorption amount.

  Further, according to the burner of the present invention, the injection angle of the fuel injection hole is such that the angle range seen on both sides with respect to the central axis of the fuel injection pipe in which each fuel injection hole is formed is 60 ° or less. It is characterized by

  With regard to the injection angle of the fuel injection holes, the angle range seen on both sides with respect to the central axis of the fuel injection pipe is set to a range of 60 ° or less, so that the injection angle is inclined toward the central axis. Thus, heavy oil can be present as long as possible with respect to the hydrogen region formed by injecting hydrogen from the hydrogen injection holes, and as much as possible with respect to air located outside the hydrogen region. It can lead you late. Therefore, the combustion of the fuel oil under oxygen can be promoted, and the emissivity can be increased.

Further, the burner of the present invention is provided with a plurality of fuel injection holes for injecting a fuel gas, and a plurality of hydrogen injection holes provided next to each of the fuel injection holes for injecting hydrogen smaller in diameter than the fuel injection holes. And each of the fuel injection holes and an air supply unit for supplying combustion air from around the hydrogen injection holes, and the fuel gas injected from each of the fuel injection holes may be burned under a deficiency of oxygen. It features.

A hydrogen injection hole for injecting hydrogen is disposed next to the fuel injection hole for injecting the fuel gas. The hydrogen injection hole is smaller in diameter than the fuel injection hole. Therefore, the fuel gas injected from the fuel injection holes is supplied with more fuel than the hydrogen injection holes, so the fuel gas becomes excessive and combustion occurs under oxygen deficiency.
On the other hand, in the hydrogen injected from the hydrogen injection holes, the burning speed of hydrogen is higher than the burning of the fuel gas and the oxygen is consumed because the burning speed of the hydrogen is faster than that of the fuel gas. Thereby, the fuel of fuel gas can be further performed under oxygen deficiency.
Since the fuel gas can be stably burned under oxygen deficiency in a state in which hydrogen becomes a flame retardant, even if hydrogen is mixed as a fuel, the radiation heat transfer performance in the furnace is prevented from being degraded. It becomes possible to secure sufficient furnace heat absorption.

  In addition, a boiler according to the present invention is characterized by including the burner described in any of the above.

  Since any of the above burners is provided, stable combustion can be performed even if hydrogen is mixed with fuel. Therefore, the hydrogen mixed combustion can be realized without making a significant change in the boiler structure.

  Moreover, the ship of the present invention is characterized by being provided with the above-mentioned boiler.

  Since the above-described boiler is provided as a marine boiler, it is possible to provide a ship provided with a boiler that realizes hydrogen-mixed combustion without performing a significant structural change.

  By actively introducing the combustion of fuel oil or fuel gas in the absence of oxygen, it is possible to compensate for the decrease in the amount of radiant heat transfer due to hydrogen combustion, so no significant boiler structure change is required.

BRIEF DESCRIPTION OF THE DRAWINGS It is the longitudinal cross-sectional view which showed the marine boiler which concerns on one Embodiment of this invention. It is the front view which showed the burner of FIG. It is the longitudinal cross-sectional view which showed the injection angle of the heavy oil injected from the burner of FIG. The injection state from a burner is shown, (a) is the longitudinal cross-sectional view which showed one Embodiment, (b) is the longitudinal cross-sectional view which showed the reference example. It is a front view showing a burner concerning a 2nd embodiment.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.
First Embodiment
FIG. 1 shows a marine boiler (hereinafter simply referred to as “boiler”) 1 according to the present embodiment. The boiler 1 is installed on a ship and used to drive a main engine of the ship.

  The boiler 1 is a twin-tube water tube boiler. The boiler 1 includes a plurality of burners 3 in a wind box 14 installed in the upper part of the furnace 2. In FIG. 1, one burner 3 is shown, but another burner 3 is installed in a direction perpendicular to the paper surface.

  The burner 3 burns heavy oil (fuel oil) and hydrogen using burner air as combustion air introduced via the air duct 13 to generate combustion gas. A cylindrical throat 15 is attached to the lower part of the burner 3, and the inside of the throat 15 is a frustoconical hollow portion whose diameter increases as it proceeds to the furnace 2 side. The burner 3 includes swirl vanes 16a and 16b (see FIG. 2), and the swirl jet is jetted by swirling the burner air by the swirl vanes 16a and 16b. The swirling jet flows downward from above in the furnace 2 and is directed to the side of the front bank tube 4 located downstream of the combustion gas flow.

  The swirling jet injected from the burner 3 forms a flame, and the high-temperature combustion gas generated thereby is generated by a front bank tube 4, a superheater 5, and an evaporation tube group (downstream of the combustion gas flow in the furnace 2 ( Pass the evaporator 6 sequentially.

  The front bank tube 4 is composed of a large number of heat transfer tubes, is provided from the bottom to the top, and is arranged in a plane so as to be orthogonal to the combustion gas flow. The front bank tube 4 connects between a header 12 provided below the furnace 2 and an upper steam drum 10.

  The superheater 5 is composed of a large number of heat transfer tubes, is provided parallel to the front bank tube 4 from the lower side to an intermediate position in the upper side, and is arranged in a plane to be orthogonal to the combustion gas flow. The superheater 5 is connected to two headers 11 provided below the furnace 2. That is, saturated steam is supplied from one header 11, flows upward in the heat transfer tube, turns back at the top portion 5 a, and then flows downward, and then is heated to a superheated state by the combustion gas and led to the other header 11. .

  The evaporation tube group 6 is composed of a large number of heat transfer tubes, is provided parallel to the superheater 5 from the lower side to the upper side, and is arranged in a plane so as to be orthogonal to the combustion gas flow. The evaporation tube group 6 connects between the lower water drum 9 and the upper steam drum 10. As the water in the lower water drum 9 is heated and evaporated, the water rises upward and steam is introduced into the steam drum 10. The saturated steam in the steam drum 10 is led to the header 11 of the superheater 5 through a path (not shown) so as to be overheated.

  Combustion gas that has exchanged heat with water and steam flowing in the heat transfer tubes of the front bank tube 4, the superheater 5, and the evaporator tube group 6 is discharged from the gas outlet 8 to the outside of the boiler 1 through the outlet side gas duct 7. Ru.

  A front view of the burner 3 is shown in FIG. A cylindrical fuel injection pipe 17 is provided at the center of the burner 3 along the central axis C1 of the burner 3. A plurality of fuel injection holes 18 are equiangularly spaced at the tip of the fuel injection pipe 17. It is provided in the circumferential direction.

  A cylindrical hydrogen injection pipe 19 having a central axis C <b> 1 common to the fuel injection pipe 17 is provided so as to surround the fuel injection pipe 17. A plurality of hydrogen injection holes 20 are circumferentially provided at equal angular intervals at the tip of the hydrogen injection pipe 19.

  A cylindrical air supply pipe 21a, 21b having a central axis C1 common to the hydrogen injection pipe 19 is provided in a double pipe structure so as to surround the hydrogen injection pipe 19. The air supply pipes 21a and 21b are provided with a plurality of swirl vanes 16a and 16b extending radially, and a swirling air flow is allowed to flow from the air supply portions 22a and 22b at the tips of the air supply pipes 21a and 21b. ing.

  The injection angle of the fuel injection hole 18 is shown in FIG. As shown in the figure, the injection direction of the fuel injection hole 18 is inclined with respect to the central axis C1 of the burner 3 (that is, the fuel injection pipe 17). Regarding the injection angle of the fuel injection hole 18, the angle range θ viewed on both sides with respect to the central axis C <b> 1 of the burner 3 is set to 60 ° or less. Since the injection angle range of the fuel injection hole of the burner of a general heavy oil cooking boiler is in the range of 80 ° to 100 °, the injection angle of the fuel injection hole 18 of the present embodiment is narrowed.

Therefore, as shown in FIG. 4 (a), the heavy oil injected from the fuel injection hole 18 has a hydrogen flow H1 injected in parallel with the central axis C1 of the burner 3 from the hydrogen injection hole 20, as indicated by reference numeral J1. It flows with a small crossing angle. Therefore, the time until the heavy oil reaches the air flow A1 flowing on the outer peripheral side of the hydrogen injection hole 20 can be made long.
A circulation vortex R1 is formed by hydrogen injected from the hydrogen injection holes 20, and ignition by hydrogen combustion is performed. Starting from this hydrogen combustion, heavy oil is burned, and light is emitted by the fuel particles P containing carbon.

  On the other hand, in the case of the general heavy oil cooking boiler shown in FIG. 4B, since the fuel injection angle is large, the fuel oil directly faces the air flow A1 located on the outer peripheral side of the fuel injection hole 18 and the heavy oil is air. Flow A1 will be reached relatively early.

According to the present embodiment, the following effects are achieved.
Since hydrogen is injected around the fuel injection holes 18, there is a hydrogen region formed by injecting hydrogen around the fuel injection holes 18. Therefore, the heavy oil injected from the fuel injection holes 18 is injected into the hydrogen region existing around the fuel injection holes 18 before the air present on the outer periphery is encountered. In this hydrogen region, the combustion of hydrogen takes place in preference to the combustion of heavy oil because hydrogen burns at a faster rate than heavy oil. Therefore, in the hydrogen region, oxygen is consumed by hydrogen combustion, so the region becomes oxygen deficient. And heavy oil is stably burned under lack of oxygen in a state where hydrogen is a combustion-support agent. As a result, since heavy oil starts combustion under oxygen deficiency, the generation of positive soot progresses and the particle radiation rate increases. Therefore, even if hydrogen is mixed as a fuel, it is possible to prevent the radiation heat transfer performance in the furnace from being lowered and to secure a sufficient furnace heat absorption amount.

For example, comparing the case of burning heavy oil with a specific gravity of 0.9 with an excess air ratio of 1.0 and the case of burning with an excess air ratio of 0.9, the average emissivity in the flame is about three times higher. . Therefore, combustion of heavy oil under oxygen deficiency as in the present embodiment is effective for improving the radiation heat transfer performance in the furnace.
By increasing the emissivity n times, the amount of mixed hydrogen combustion can be increased, and the amount of combustion of heavy oil can be reduced to 1 / n. As a result, the ratio of the sulfur content in heavy oil to the amount of combustion decreases, so the concentration of sulfur oxides in exhaust gas decreases.
Further, according to the present embodiment, since the hydrogen co-firing can be performed, measures such as fuel conversion to low sulfur heavy oil and high performance of the desulfurization device become unnecessary.
In addition, since the amount of heavy oil burned is reduced by hydrogen co-firing, carbon dioxide emissions can be reduced.

With regard to the injection angle of the fuel injection hole 18, the angle range seen on both sides with respect to the central axis C1 of the fuel injection pipe 17 is set to a range of 60 ° or less, thereby making the injection angle inclined toward the central axis C1. . As a result, heavy oil can be present as long as possible with respect to the hydrogen region formed by injecting hydrogen from the hydrogen injection holes 20, and also possible with respect to air located outside the hydrogen region. Can lead you to Therefore, the combustion of heavy oil under oxygen can be promoted, and the emissivity can be increased.
In addition, since the combustion speed of hydrogen is sufficiently faster than that of heavy oil, stable combustion in the vicinity of the burner 3 can be expected, and even when the injection angle becomes narrower due to hydrogen acting as a combustion aid, ignition and flame holding performance Can be secured.

  In addition, as described above, the burner 3 of the present embodiment can stably perform the mixed combustion of heavy oil and hydrogen, so that it is necessary to make a significant change in the boiler structure such as changing the material of the superheater 5 or the like. Absent.

Second Embodiment
Next, a second embodiment of the present invention will be described.
The present embodiment is different from the first embodiment in that the fuel is not heavy oil but LNG (fuel gas). Therefore, although the structure of a burner differs, since the whole structure of a boiler is the same, the description is abbreviate | omitted.

FIG. 5 shows a front view of the burner 3 ′ according to the present embodiment. The burner 3 'is used for co-firing of LNG and hydrogen. A plurality of fuel injection holes 18 'are provided circumferentially at equal angular intervals in the burner 3'. Further, hydrogen injection holes 20 'are circumferentially provided at equal angular intervals between the fuel injection holes 18'. That is, hydrogen injection holes 20 'are disposed on both sides of the fuel injection holes 18'. The diameter of the hydrogen injection hole 20 'is smaller than the diameter of the fuel injection hole 18'.
An air supply unit 22 having a plurality of turning vanes 16 is provided on the outer peripheral side of the fuel injection holes 18 ′ and the hydrogen injection holes 20 ′.

According to the present embodiment, the following effects are achieved.
Hydrogen injection holes 20 'for injecting hydrogen are disposed on both sides of the fuel injection holes 18' for injecting LNG. The hydrogen injection holes 20 'are smaller in diameter than the fuel injection holes 18'. Therefore, since the fuel injected from the fuel injection holes 18 'is supplied with more fuel than the hydrogen injection holes 20', the fuel becomes excess and combustion occurs under oxygen deficiency.
On the other hand, in the hydrogen injected from the hydrogen injection holes 20 ', since the hydrogen has a higher combustion rate than the LNG, the combustion of the hydrogen is performed prior to the combustion of the LNG to consume oxygen. Thereby, the fuel of LNG can be further performed under oxygen deficiency.
Since LNG can be stably burned under oxygen deficiency in a state in which hydrogen is a combustion-support agent, it is possible to increase the amount of radiation by the emission of carbon in the LNG. Therefore, even if hydrogen is mixed as a fuel, it is possible to prevent the radiation heat transfer performance in the furnace from being lowered and to secure a sufficient furnace heat absorption amount.

  As the fuel gas to be burned by the burner 3 ′, typically, LNG is mentioned as in the present embodiment, but other fuel gas may be used, for example, LPG. Alternatively, hydrogen may be mixed with the fuel gas injected from the fuel injection holes 18 '.

DESCRIPTION OF SYMBOLS 1 Boiler 2 Furnace 3, 3 'Burner 4 Front bank tube 5 Superheater 5a Top part 6 Evaporation pipe group 9 Water drum 7 Outlet side gas duct 8 Gas outlet 10 Steam drum 11 Header 12 Header 13 Air duct 14 Wind box 15 Throat 16, 16a , 16b swirl vane 17 fuel injection pipe 18, 18 'fuel injection hole 19 hydrogen injection pipe 20, 20' hydrogen injection hole 21a, 21b air supply pipe 22, 22a, 22b air supply portion

Claims (5)

A plurality of fuel injection holes for injecting fuel oil;
A plurality of hydrogen injection holes for injecting hydrogen from around each of the fuel injection holes and forming a hydrogen region around each of the fuel injection holes ;
An air supply unit for supplying combustion air from around each of the hydrogen injection holes;
Equipped with a,
A burner characterized in that fuel oil injected from each of the fuel injection holes burns in the hydrogen region where oxygen is insufficient .   The injection angle of the fuel injection hole is such that an angle range seen on both sides with respect to a central axis of a fuel injection pipe in which each fuel injection hole is formed is set to 60 ° or less. Burner. A plurality of fuel injection holes for injecting fuel gas;
A plurality of hydrogen injection holes provided next to each of the fuel injection holes for injecting hydrogen whose diameter is smaller than that of the fuel injection holes;
An air supply unit for supplying combustion air from around each of the fuel injection holes and each of the hydrogen injection holes;
Equipped with a,
A burner characterized in that fuel gas injected from each of the fuel injection holes burns under oxygen deficiency .   A boiler comprising the burner according to any one of claims 1 to 3.   A ship comprising the boiler according to claim 4.

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