JPH0429221Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a multi-fuel spray nozzle, which has been improved to improve its responsiveness when changing the fuel mixture ratio.

BACKGROUND ART Conventionally, this type of nozzle has a structure as shown in FIGS. 6 to 9 (Utility Application No. 61-7516).

In these figures, reference numeral 24 is a first nozzle section which is a multi-fuel spray nozzle, and reference numeral 25 is a second nozzle section for forming a flame. Both nozzle parts 24 and 25 constitute a burner.

The second nozzle section 25 has the same structure as the conventional one, but the first nozzle section 24 includes a liquid fuel supply pipe 26 and an atomizing medium supply pipe 28 for atomizing the liquid fuel as shown in the figure. There is. The liquid fuel supply pipe 26 is coaxially inserted into the spray medium supply pipe 28 and is held via a spacer (not shown). Further, the liquid fuel supply pipe 26 is set so that its tip is located near the connection between the second nozzle section 25 and the first nozzle section 24, and the tip is closed with an end plate 27. Four liquid fuel injection holes 29 are bored in the peripheral wall at 90° intervals.

A mixing section 30 for different fuels is provided at the rear end of the fuel supply pipe 26 . The mixing section 30 consists of a nut member 32 and a bolt member 33 that form a mixing chamber 31 between them. Female threads 36 that engage with the bolt member 33 are provided at the front and rear, respectively, and the bolt member 33 has a male thread 37 that engages with the female thread 36, as well as a male thread 37 that communicates with the rear end of the fuel supply pipe 26 and connects it. A closed cavity 38 is provided. Mixing chamber 3
1 is provided at a location that is closed by each of the screws 34, 35, 36, and 37, and four holes 39 communicating therewith are bored in the bolt member 33 at 90° intervals. The nut member 32 also has four fuel supply ports 40, 41, 42, as shown in FIG.
43 is provided in a direction tangential to the mixing chamber 31.

Therefore, in this case, four types of fuel can be supplied simultaneously.

In FIG. 6, reference numeral 44 is a spray medium supply port provided at the rear end of the spray medium supply pipe 28.

The burner having the above configuration is used for combustion in an industrial furnace 45 as shown in FIG. 9, for example. In this case, each pipe 46, 47 connected to the fuel supply pipe 26 is provided with a flow rate regulating valve 48, 49, and the exhaust gas flow path 50 of the furnace 45 is provided with a nitrogen oxide (NO _x ) measuring device 51.
are provided, and both 51, 48, and 49 are in communication via a controller 52.

Therefore, if two types of fuels with different nitrogen contents are to be co-combusted, first a desired _NO The water is allowed to flow into the chamber 31. The other fuel is sent in the direction of arrow E to flow in from the fuel supply port 41. Note that the other ports 42 and 43 are closed with plugs or the like. Since both fuels flow tangentially into the mixing chamber 31, they quickly mix while swirling, and then pass through the hole 39 into the cavity 38 and flow through the fuel supply pipe 26 into the injection hole 2.
Proceed towards 9. At the same time, a spray medium such as air flows at high speed in the direction of arrow F in the spray medium supply pipe 28 toward the second nozzle part 25, and liquid fuel is jetted from the liquid fuel jet hole 29 of the liquid fuel supply pipe 26. , atomized. Since liquid fuel particles are ejected radially from each ejection hole 29, they do not collide with each other and reach the second nozzle part 25 with the same size as when ejected, where they are further atomized and sent to the furnace. 45 and forms a flame 53.

During combustion, if the measured value of the measuring device 51 fluctuates, a signal is sent from the controller 52 to each flow regulating valve 4 to return it to the set value in the controller 52.
It is output on 8,49.

Adjustment of the fuel flow rate by each of the flow rate regulating valves 48 and 49 appears as a change in the amount of fuel ejected from the ejection hole 29, thereby achieving combustion that returns the _NOx value to an appropriate value.

Furthermore, in the above device, if the fuel is not mixed uniformly in the mixing chamber 31, the combustion flame 53 will be uneven, making it impossible to obtain good blended combustion. Therefore,
As shown in FIG. 10, a static mixer 54 is provided within the fuel supply pipe 26 to more uniformly mix and stir the supplied plural types of fuel.

Problems to be Solved by the Invention However, in the conventional nozzle described above, when the difference in the supply pressures of each liquid fuel becomes large, the fuel with lower pressure may be defeated by the fuel with higher pressure and may not flow into the mixing chamber 31. In such a case, the intended mixture ratio cannot be obtained and good blend combustion cannot be obtained.

Furthermore, since the distance from the liquid fuel mixing section to the ejection hole 29 is long, there is a problem in that there is a delay in response when performing various feedback controls such as _NOx feedback.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a system in which pipes for supplying a plurality of types of liquid fuel are connected to a liquid fuel supply pipe in the spray medium supply pipe, and the pipes are supplied from each pipe. In a multi-fuel spray nozzle in which a mixing part for mixing liquid fuels is installed at a predetermined location of the liquid fuel supply pipe, the liquid fuel supply pipe is a multi-layered pipe with a front end closed, and the rear end of each pipe is closed. Each of the liquid fuel pipes is connected to each of the pipes, and liquid fuel injection holes penetrating from the inside of each pipe at the front part of the multiple pipe toward the atomizing medium supply pipe are provided close to each other in the front-rear direction. A configuration is adopted in which the front periphery of the multi-tube serves as the mixing section.

Function Each fuel is ejected in liquid form from each nozzle and atomized by the atomizing medium, and at the same time, the fine particles mix with each other in the form of a mist, and are evenly mixed before reaching the flame-forming nozzle, after which they are subjected to combustion. Ru.

Even if the flow rate of one of the fuels is throttled due to feedback control, the flow of fuel is not obstructed by the flow of other fuels until it reaches the nozzle, so that an appropriate amount is accurately jetted from the nozzle.

Also, the mixing section is located at the location where the injection holes are present, so the feedback signal immediately appears as a change in the blending ratio of the fuel.

Embodiment FIGS. 1 to 5 show an embodiment of the present invention. In these figures, reference numeral 1 is a first nozzle section which is a multi-fuel spray nozzle, and reference numeral 2 is a second nozzle section for forming a flame. Both nozzle parts 1 and 2 constitute a burner.

The second nozzle section 2 has the same configuration as the conventional one, but the first nozzle section 1 is equipped with a liquid fuel supply pipe 3 and an atomizing medium supply pipe 4 for atomizing the liquid fuel as shown in the figure. There is. The liquid fuel supply pipe 3 is coaxially inserted into the atomizing medium supply pipe 4 and is a multi-tube consisting of an outer pipe 5 and an inner pipe 6, and has a kind of fuel flow path 7 with a gap between both pipes 5 and 6. The inside of the inner tube 6 is set as a flow path 8 for other types of fuel.

At the rear ends of both pipes 5 and 6, there are flow passages 7,
pipes 10, 9 for supplying different fuels to 8, respectively;
are connected, and the tube 9 is an extension of the inner tube 6.
Further, the tube 10 is provided separately from the outer tube 5.

The fuel mixing section 1 is located at the front end of both the inner and outer pipes 6 and 5.
1 is provided. The mixing part 11 includes both inner and outer pipes 6,
5 is formed as a separate body for manufacturing reasons, and is made in the shape of a cap that closes the front ends of both the inner and outer tubes 6, 5, and a blind hole 12 is provided at the location corresponding to the flow path 8.
is provided, and an annular groove 13 is provided at a location corresponding to the other flow path 7. And blind hole 1
2 protrudes further forward than the annular groove 13,
As shown in FIGS. 2 to 4, three fuel injection holes 14 and 15 are formed in each of the distal ends thereof, penetrating the outer periphery. In this case, the two holes 14, 15 are radially provided with an offset of 60° as shown in FIGS. 3 and 4. This is to prevent fine particles of fuel from colliding with each other and coalescing to become large particles when fuel is ejected from the fuel injection holes 14 and 15 as will be described later.

In FIG. 1, reference numeral 16 is a spray medium supply port provided at the rear end of the spray medium supply pipe 4. As shown in FIG.

The burner having the above configuration is used for combustion in an industrial furnace 17, for example, as shown in FIG. In this case, each pipe 9, 10 is provided with a flow rate regulating valve 18, 19, respectively, and the exhaust gas flow path 20 of the furnace 17 is provided with a nitrogen oxide (NO _x ) measuring device 21.
9 and 21 are in communication via a controller 22.

Therefore, if two types of fuels with different nitrogen contents are to be co-combusted, the desired _NO
10. Supply each flow path 8, 7 in the direction of arrows A and B to reach each jet hole 14, 15. At the same time, the atomizing medium, air or steam, enters the supply pipe 4 with arrow C.
The flow causes each ejection hole 14,
The fuel ejected from 15 is atomized. The fine particles of each fuel are uniformly mixed before reaching the second nozzle section 2 and are sprayed from the second nozzle section 2, forming a flame 23.

In this way, the fuel can be atomized and sent into the furnace 17 in a uniform flow, so a uniform flame pattern without eccentricity can be obtained, resulting in high turndown and
Low O ₂ combustion can be achieved, and furthermore, it is possible to ensure the atomization of liquid fuel spray, or to promote atomization, thereby reducing the amount of pollutants and improving combustibility.

During combustion, if the measured value of the measuring device 21 fluctuates, a signal is sent from the controller 22 to each flow regulating valve 1 to return it to the set value in the controller 22.
It is output on 8 and 19.

Adjustment of the fuel flow rate by each flow rate regulating valve 18, 19 immediately appears as a change in the amount of ejection from the ejection holes 14, 15, and therefore combustion that returns the _NOx value to an appropriate value can be immediately obtained.

Effects of the invention Since the present invention has the above-mentioned structure and operation, there is no fear that any fuel will stop coming out of the nozzle even if the supply pressure becomes low, and spray with the intended blend ratio can always be obtained. , which can form an appropriate flame.

In addition, since there is a fuel injection hole in the mixing part,
Good responsiveness in various feedback controls,
Therefore, the _NOx value can always be properly controlled.

[Brief explanation of the drawing]

1 to 5 show one embodiment of the present invention, FIG. 1 is a partially cutaway side view of a multi-fuel spray nozzle of this embodiment incorporated into a burner, and FIG. 2 is a part of the part shown in FIG. 1. Figures 3 and 4 are enlarged views of Figures 2 and 5, respectively.
The figure is a system diagram showing the case where the above burner is applied to an industrial furnace, Figures 6 to 10 show a conventional example, and Figure 6 is a partially cutaway side view showing a conventional multi-fuel spray nozzle installed in the burner. , Fig. 7 and Fig. 8 are cross-sectional views taken along lines - and -, respectively, in Fig. 6, Fig. 9 is a system diagram showing the case where the burner is applied to an industrial furnace, and Fig. 10 is a cross-sectional view of the burner in a multi-fuel spray nozzle. FIG. 7 is a side view similar to FIG. 6 but with a mixer; 1... Multi-type fuel spray nozzle, 2... Second nozzle part, 3... Fuel supply pipe, 4... Spray medium supply pipe,
11...Mixing section.

Claims (1)

[Scope of utility model registration request] Pipes for supplying each of the plurality of types of liquid fuel are connected to a liquid fuel supply pipe in the spray medium supply pipe, and a mixing section for mixing the liquid fuels supplied from each pipe is located at a predetermined location of the liquid fuel supply pipe. In the installed multi-fuel spray nozzle, the liquid fuel supply pipe is a multi-pipe whose front end is closed, each pipe for the liquid fuel is connected to the rear of each pipe, and the multi-pipe In the front part, liquid fuel injection holes penetrating from inside each pipe toward the atomizing medium supply pipe are provided close to each other in the front-rear direction, and the peripheral part of the front part of the multiple pipes serves as the mixing part. The above-mentioned multi-fuel spray nozzle is characterized in that: