JPH1026312A - Atomization type burner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost of an atomization type burner. SOLUTION: In an atomization type burner of which a fuel nozzle 1 is constructed of a single-wall tube and wherein liquid fuel supplied, with pressurized gas, to the base end part of this single-wall tube 1 is atomized in the tube and jetted from a fore-end nozzle hole 2, the single-wall tube 1 is made 50cm or more long and also the flow rate in the tube is made 30m/sec or above. Accordingly, the structure of the fuel nozzle of an intramixing type burner of a large capacity which have necessitated a double-wall tube in the prior arts can be simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an atomizing type burner of an internal mixing type which atomizes and ejects a liquid fuel by high-pressure air or steam.

[0002]

2. Description of the Related Art As shown in FIG. 1, this type of atomizing type burner supplies pressurized air or steam together with a liquid fuel to a base end of a fuel nozzle 1 and a mixing nozzle provided near a front end thereof. The liquid is atomized in the chamber 7 and is ejected from the tip nozzle hole 2. The reason why the mixing chamber 7 is provided in the vicinity of the tip of the nozzle 1 is that when the mixing chamber 7 is long, fine particles of the liquid fuel once atomized reaggregate and become large, and the contact area with the air becomes small. This is because the flammability decreases and the combustibility deteriorates.

On the other hand, the fuel nozzle 1 is provided through the center of a wind box (wind box) 8 for supplying combustion air, and the wind box 8 has a cylindrical portion for mounting on a furnace wall. Since the flange portion is formed, the fuel nozzle 1 is often required to be long, for example, having a total length of about 1.5 to 2.0 m. Therefore, conventionally, as shown in FIG. 1, the fuel nozzle 1 is composed of double pipes 1a and 1b, and pressurized gas and liquid fuel are separately supplied up to the mixing chamber 7 at the tip, and the nozzle is immediately after mixing. The gas was ejected from the hole 2.

[0004]

However, in the above-mentioned conventional system, the structure of the fuel nozzle 1 is generally complicated and an oil pump for pressurizing the liquid fuel is also required. On the other hand, there is a disadvantage that the cost is significantly increased. As for a small burner with a small capacity, a single tube type nozzle as shown in FIG. 4 has been tried. However, when this method is applied to a large burner, as shown in a measurement result B in FIG. As the particle size increases, the particle size of the atomized fine particles ejected from the nozzle rapidly increases, and the flammability deteriorates, causing a problem that the flame becomes longer and soot and carbon monoxide are easily generated.
The present invention has been made in view of such a problem, and has, for example, 1 million kcals.
It is an object of the present invention to provide an atomizing type burner of this type which can simplify the structure of the fuel nozzle 1 and achieve a significant cost reduction even in a large capacity burner of about / h.

[0005]

As shown in FIG. 2, an atomizing type burner according to the present invention comprises a fuel nozzle 1 formed of a single pipe, and a liquid supplied to a base end of the single pipe 1 together with a pressurized gas. In the atomizing type burner in which the fuel is atomized in the pipe and is ejected from the tip nozzle hole 2, the length of the single pipe 1 is set to 50 cm or more, and the flow rate in the pipe is set to 3 or more.
0 m / sec or more. In order to increase the flow velocity in the pipe in this manner, the diameter of the pipe is reduced, the ratio of the total area of the tip nozzle hole to the cross-sectional area of the pipe is increased, and the area of the pressurized gas connection 3 at the base end of the nozzle is increased. Just do
For example, a flow velocity of about 90 to 100 m / sec can be easily realized with a pipe diameter of 4 mm.

[0006]

The reason why the particle diameter of the atomized fine particles can be reduced by increasing the flow velocity in the pipe as described above is considered as follows. That is, the reagglomeration of the atomized fine particles is hardly performed in the air due to the obstruction of the airflow, and is mostly performed on the tube wall. Therefore, by increasing the flow velocity in the tube and shortening the time from the time when the atomized fine particles adhere to the tube wall to the time when they are separated, the chance of reagglomeration of the fine particles decreases, and the atomization regardless of the length of the tube It is possible to maintain the particle size at the initial stage of chemical conversion.

[0007]

1 and 2 show an embodiment of an atomizing type burner according to the present invention.
Is constituted by a single pipe, and steam (or air) is supplied to the base end of the single pipe 1 through the connecting portion 3 having a sufficiently large cross-sectional area as compared with the conventional example of FIG. A pipe is connected, and a thin pipe 4 for injecting liquid fuel protrudes from a pipe wall near the base end. The liquid fuel is sucked into the pipe and atomized by the atomizing effect of the high-velocity vapor stream,
It is ejected from the nozzle hole 2. A secondary air supply cylinder 5 is provided concentrically on the outer periphery of the fuel nozzle 1, and this air flow is swirled and stirred by a flame holding swirl plate 6 protruding from the vicinity of the tip of the nozzle 1 to the periphery. Thereafter, the fuel is mixed with the atomized fuel and burned.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel nozzle is constituted by a single pipe with an inner diameter of 4 mm and a length of 1 m, the number of nozzle holes at the tip is 1.5 mm × 4, and pressurized gas is 4 m ³ / h of air at a pressure of 4 kg / cm ² G (apparent). flow rate 20 m ³ / hour) of, when the liquid fuel and kerosene 20 l / h, air velocity becomes 88m / sec, the average particle size of the atomized fuel injected from the nozzle hole of about 50μm
(Substantially the same as when the tube length was set to 0). The diameter of the connection at the base end of the nozzle was the same as the diameter of the pipe, the liquid fuel was supplied under pressure by a pump, and the liquid fuel supply port (small pipe) was not projected from the inner wall surface.

FIG. 5 shows that only the inner diameter of the tube is changed, and other conditions are the same as in the above embodiment, and the inner diameter (or the flow velocity in the tube) is changed.
5 shows the results of measuring the change in the particle size of the fine particles ejected from the nozzle hole. At a flow velocity of about 30 m / sec, the particle size of the sprayed fine particles sharply increases. Inner diameter 1
It is considered that the reason why the particle size is saturated at 2 mm or more (flow rate 10 m / sec or less) is that if the particle size is large, peeling is likely to occur even at a low flow rate.

[0010] Next, FIG. 6 shows the nozzle A having a 10 mm inner diameter (conventional type in FIG. 4) and the nozzle B having an inner diameter of 4 mm (the above-described embodiment type), in which the particle diameter of the sprayed fine particles when only the pipe length is changed. It is a result of the measurement. In the product A of the present invention, the particle size (50 μm) at the initial stage of atomization is maintained almost without being affected by the tube length.

As described above, the present invention focuses on the point that reagglomeration of atomized fine particles is mainly performed on the tube wall, and increases the flow velocity of the pressurized gas in the tube so that the atomized fine particles adhere to the tube wall. To reduce re-agglomeration of the fine particles by reducing the time required for the atomization type burner fuel nozzle of high capacity that could not be realized without the conventional structure of the double pipe. Can be realized with a very simple single-pipe structure, and the cost can be significantly reduced. Also, the supply of the liquid fuel does not need to be pressure-fed to the tip of the nozzle as in the conventional internal mixing type, so that an air-flow spraying method in which atomization is performed by the kinetic energy of the air flow can be adopted, and an oil pump can be omitted.

[Brief description of the drawings]

FIG. 1 is an overall sectional view common to the present invention and a conventional example.

FIG. 2 is a longitudinal sectional view of a fuel nozzle used in the present invention.

FIG. 3 is a longitudinal sectional view showing a conventional example of a fuel nozzle.

FIG. 4 is a longitudinal sectional view showing another conventional example of a fuel nozzle.

FIG. 5 is a graph of measured data showing the operation principle of the present invention.

FIG. 6 is a graph of comparison data between the product of the present invention and a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel nozzle 2 Nozzle hole 3 Connection port 4 Steam supply pipe 5 Small pipe 6 Combustion air supply pipe 7 Mixing chamber 8 Wind box

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Masaichi Exit 3-3-25, Shochitsuda, Hirakata-shi, Osaka

Claims (1)

[Claims] 1. An atomizing type burner in which a fuel nozzle is constituted by a single pipe, and a liquid fuel supplied to a base end of the single pipe together with a pressurized gas is atomized in the pipe and ejected from a tip nozzle hole. An atomizing type burner characterized in that the length of the single pipe from the fuel supply section to the nozzle hole is at least 50 cm and the flow velocity in the pipe is at least 30 m / sec.