JPS61168710A - Burner - Google Patents

Abstract

PURPOSE:To make possible low air ratio combustion without increasing dusts in the exhaust gas by providing in a nozzle a confluence hole section in which pressurized air and pressurized fluid fuel mix together and making the ratio of L to d more than 1.5, where L is the dimension between the confluence junction and the confluence hole outlet point and d is diameter of the fluid fuel hole. CONSTITUTION:An atomization gas 1 of a high speed given by its passing from an atomization gas chamber 2 to an atomization gas inlet hole 3 accelerates a fluid fuel 4 supplied from a fluid fuel hole 5 and the fuel flows out atomized from the confluence hole 6. The point where the fluid fuel 4 and the atomization gas 1 start exchanging their momenta between them is near the confluence junction point, and from here atomization due to the momentum exchange starts. Certain distance is required for sufficient momentum exchange (atomization effect) of two fluids. According to a test with water, a ratio L/d less than 0.5 does not develop sufficient atomization but develops atomization of coarse particles with streaked atomized particles, and they become extremely minute around at L/d=1.5. By this minute atomization the state close to gas combustion is obtained, allowing low air ratio combustion.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a two-fluid atomizing nozzle, and more particularly to a combustion device that is capable of studying the atomization characteristics of liquid fuel and capable of low air ratio combustion.

<Prior art and its problems> As two-fluid spray nozzles according to the prior art, a Y-jet nozzle and an internal mixing nozzle are in practical use. In particular, for large-capacity spray nozzles, Y-jet nozzles are used because of the requirements for simple structure and long life. The Y-jet nozzle according to the prior art does not have sufficient atomization characteristics based on momentum exchange between the atomized gas and the liquid fuel, and therefore has the following problems.

(1) Due to the poor W conversion efficiency, the average atomized particle size is large, which results in a long flame.

(2) Because the atomized average particle size is large, black colored smoke is likely to be produced and low air ratio combustion cannot be achieved.

(3) Atomization gas consumption is large due to poor atomization efficiency;
This results in low plant efficiency.

(4) Because low air ratio combustion is not possible, nitrogen oxides (
(hereinafter referred to as NOx) emissions are large.

(5) For high viscosity, low quality oil, good combustion cannot be obtained unless the preheating temperature is increased.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide a boiler device capable of low air ratio combustion without increasing soot and dust in exhaust gas.

Summary of the Means> In summary, the present invention is a device for spraying and burning pressurized fluid fuel using pressurized gas, and in which a merging hole is provided in a nozzle where pressurized gas and pressurized fluid fuel mix. A section is provided at the junction hole intersection (10) and the junction hole exit point (11).
L, the ratio of the dimension between (L) and the fluid fuel hole diameter (d)
/a is 1.5 or more.

<Example 1> Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a cross section of the tip of a Y-jet nozzle, which is the object of the present invention. The atomizing gas 1 is usually compressed air or steam having pressure. After the pressure of the atomized gas 1 is regulated, the atomized gas 1 is led to the atomized gas chamber 2 and is supplied to the confluence hole 6 through one or more atomized gas inlet holes 3 provided.

On the other hand, the liquid fuel 4 is pressurized by a pressure pump, and in the case of viscous low-quality oil such as heavy oil or coal slug IJ + fuel, the liquid fuel 4 is reduced in viscosity by means such as preheating. ), the fuel flow rate is adjusted, and the liquid fuel is supplied to the merging hole 6 via the liquid fuel hole 5. In the confluence hole 6, momentum is exchanged between the atomized gas 1, which has become a high-speed flow, and the liquid fuel 4, and the atomized gas is atomized and flows into the furnace from the confluence hole end of the nozzle.
be misted.

FIG. 2 shows a view from A in FIG. 1, and eight merging holes 6 can be seen. The number of merging holes 6 is not particularly limited, nor is the arrangement thereof in any way limited. That is, it may be one or more.

, FIG. 3 shows details of section B in FIG. 1.

The atomized gas 1 that has become high-speed through the atomized gas inlet hole 3 from the atomized gas chamber 2 accelerates the liquid fuel 4 supplied from the liquid fuel hole 5 (hole diameter is d), and flows through the confluence hole 6. It flows out in an atomized state. Now, in the population of the liquid fuel hole 5, the fuel hole inlet inner point 8 is defined as the fuel hole inlet inner point 9, and the outlet of the liquid fuel hole 5 is defined as the fuel hole inlet inner point 9. Let the intersection with the side wall be the merging hole intersection 10.

Let L be the distance from the junction hole intersection 10 to the outlet of the junction hole 6, and let d be the hole diameter of the liquid fuel hole. Note that the diameter b6 of the merging hole 6
The ratio of the inlet pore diameter d to the inlet pore diameter d is preferably about 1.6 to 1.8.

The starting point of momentum exchange between the liquid fuel 4 and the atomized gas 1 is substantially at the intersection of the stream holes, from which atomization by momentum exchange begins. As is well known, sufficient momentum exchange (atomization) between two fluids requires a certain distance.

FIG. 4 shows an example of test results using water, with L/d plotted on the horizontal axis and average atomized particle size on the vertical axis. Fourth
As is clear from the figure, when L/a is less than 0.5, sufficient atomization is not achieved and coarse particles are sprayed in streaks. It became clear that the average atomized particle size became finer when L/a was around 1.5.

Also, liquid fuel hole 5. Nitrogen gas population hole 3 and confluence hole 6
The shape of the hole is usually circular, but if it is polygonal instead of circular, and if there are multiple liquid fuel holes 5, the hydraulic diameter dh
It can be treated as 0 dh=Complete... (In here, J-: Length of wetted edge, outlet edge of fluid fuel hole 15) a: Cross-sectional area of hole <Example 2> Fig. 5 This shows a second embodiment, in which a spiral groove 12 is provided in the merging hole 6. The grooves allow good mixing of the fluid fuel and the atomizing gas, and proper atomization allows for good combustion. As for the spiral groove, it is desirable that the groove depth becomes shallower as it approaches the edge of the merging hole 6 (the edge of the hole where the exit point 11 is located). If the depth is the same up to the outlet end of the merging hole 6, there is a risk that streaks of rich hole fuel will form in the spray of fluid fuel.

Effect> The first effect of implementing the present invention is that the average atomized particle size of the fluid fuel becomes finer, so that the flame becomes shorter. This makes it possible to downsize the furnace. The second effect of the present invention is that the miniaturization brings the state close to gas combustion, allowing low air ratio combustion and improving boiler efficiency. The third effect of the present invention is that the consumption of atomizing gas can be reduced due to improved atomization efficiency, and plant efficiency can be improved.

The fourth effect of the present invention is that due to low air ratio combustion, NO
The amount of x emitted can be reduced, and low-pollution combustion becomes possible. The fifth effect of the present invention is that even low-quality oil can be burned well, so the economic advantage is extremely large.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a Y-jet nozzle to which the present invention is applied, FIG. 2 is a view from A in FIG. 1, and FIG. 3 is a detailed view of part B in FIG. Drawings, Figure 4 is a diagram showing an example of the test results of the Y-jet nozzle, and Figure 5 is a diagram showing an example of the test results of the Y jet nozzle.
It is a partial sectional view when a spiral groove is provided in the merging hole 6 in an example. 1... Atomized gas 2... Atomized gas chamber 3... Atomized gas inlet hole 4... Liquid fuel 5... Liquid Fuel hole 6... Merging hole 7... Nozzle tip body 8... Fuel hole inlet internal point 9... Fuel hole inlet internal point 10... ... Merging hole intersection 11 ... Merging hole exit point

Claims (1)

[Claims] 1. In a device that sprays and burns pressurized fluid fuel with pressurized gas, a nozzle has a confluence hole where the pressurized gas and pressurized fluid fuel mix. and the dimension (L) between the junction hole intersection (10) and the junction hole exit point (11).
) and the fluid fuel hole diameter (d), L/d, is set to 1.5 or more. 2. The combustion device according to claim 1, characterized in that a spiral groove is provided in the merging hole portion.