JPS5825927B2 - oil burner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oil burner in which NOx in combustion exhaust gas is reduced.

Conventionally, the mainstream methods for reducing NOx in burner exhaust gas have been the exhaust gas recirculation method, in which the combustion exhaust gas is mixed into the combustion air, and the staged combustion method, in which the combustion air is divided into multiple stages and sucked into the furnace. However, recently, research has been conducted to achieve low NOx levels in the burner itself.

One such method uses a premix burner in the case of gas combustion.

This is done by arranging burners with a small air ratio and burners with a large air ratio side by side, taking advantage of the phenomenon that the amount of NOx generated decreases when the premixed coal has a small air ratio and a large air ratio, as shown in Figure 1. However, surplus combustion air from the burner with a high air ratio is supplied to the flame of the burner with a low air ratio at the burner outlet, so that the necessary combustion air is finally provided.

However, this burner is for gas fuel, and the method for supplying the combustion air described above, that is, the method of supplying the surplus air of the burner with a high air ratio to the flame of the burner with a low air ratio, is simply by arranging both burners side by side. This is a serious drawback.

This is because combustion of gas fuel inherently generates a small amount of NOx, and it is overwhelmingly in oil burners that measures to reduce NOx are required.

Furthermore, the method of supplying surplus air from a burner with a high air ratio to the flame of a burner with a low air ratio is none other than the staged combustion method.

For example, in the two-stage combustion method, the method of supplying secondary air affects the amount of NOx produced, but even more so it affects the generation of soot.

The effect is more pronounced in oil combustion than in gas combustion, so
In oil combustion, if this secondary air is simply supplied as residual air from the flames of adjacent burners,
This is because the soot is supplied only to the part that contacts the adjacent burner and does not penetrate into the center of the flame, which may cause a large amount of soot to be generated.

On the other hand, the diffusion flame of an oil burner does not have the characteristic that the amount of NOx produced is significantly reduced when the air ratio is large like the gas combustion premixed flame, so the above NOx reduction measures cannot be used.

Premixing in an oil burner also has the disadvantage that it is difficult to perform because it is difficult to vaporize the fuel oil.

An object of the present invention is to provide an oil burner that eliminates the drawbacks of the above-mentioned prior art, maximizes the effect of two-stage combustion even when oil is used as fuel, and can reduce NOx in combustion exhaust gas. .

In the oil burner of the first aspect of the present invention, an air box is formed at the base and a combustion chamber is formed at the tip, and the space between the fuel chamber and the air chamber is tapered from the fuel chamber side to reduce the diameter. The burner body has a cylindrical burner body which is connected to a trapezoidal conical hole, and the air chamber has an air introduction pipe that opens in the tangential direction. A conical body having an inclination in the direction is loaded with the axes aligned, a wheat culm is provided on the conical body protruding from the top in the axial direction, and the conical body is attached to the base end of the burner body with the wheat culm. The conical body is supported so as to be movable in the direction, and a plurality of two types of oil injection holes with different diameters are opened alternately in the circumferential direction on the conical surface of the conical body, and the wire holes are oil injection holes drilled in the wheat culm. This oil burner is characterized in that it communicates with an introduction hole.

In a preferred embodiment of the oil burner of the first aspect of the present invention, swirling vanes for swirling the air flow or the mixed gas flow of air and oil are attached to the conical tub of the conical body.

In the oil burner of the second invention according to the present invention, an air chamber is formed at the base and a combustion chamber is formed at the tip, and the diameter between the combustion chamber and the air chamber is tapered from the combustion chamber side. It has a cylindrical burner body that communicates with a first trapezoidal hole and a second trapezoidal hole that is tapered and enlarged in diameter, and the air chamber has a tangential line. The second hole has a trapezoidal conical ring having a peripheral surface inclined in the same direction as the wire hole and a trapezoidal conical hole inclined in the opposite direction. The conical trapezoidal ring is loaded with its centers aligned, and the conical trapezoidal ring has a plurality of ronds protruding from the bottom, and the ring is supported by the rond part so as to be movable in the axial direction at the base end of the burner body; A conical body inclined in the same direction as the wire hole is inserted into the trapezoidal hole of the ring, with its axes aligned, and a barley culm is provided protruding from the top in the axial direction. A conical body is supported for axial movement at the proximal end of the burner body in the wheat culm, and a plurality of oil jets are provided on the conical surface of the conical body and on the inner wall forming the second hole of the burner body. This oil burner is characterized in that the holes are open and each jetting hole is communicated with an oil introduction hole bored in the wheat culm and an oil introduction pipe provided on the outer peripheral surface of the burner body.

The oil burner according to the present invention will be explained in detail below.

First, the oil burner of the first invention is shown in the second embodiment of the drawings.
This will be explained based on the diagram and FIG.

This oil burner has a cylindrical burner body 5.

An air box 2 is formed at the base of the burner body 5, and a combustion chamber 5a is formed at the tip.

The combustion chamber 5a and the air box 2 communicate with each other through a trapezoidal hole 3 whose diameter is tapered and reduced from the combustion chamber side.

An air introduction pipe 1 which opens in the tangential direction is provided on the peripheral wall of the air box 2, and the air introduced from the air introduction pipe 1 forms a swirling flow within the air box 2.

A conical body 4 inclined in the same direction as the hole 3 is inserted into the trapezoidal hole 3 with its axes aligned.

A supporting frame 11 is provided to protrude from the top of the conical body 4 in the axial direction, and the conical body 4 is supported by the wheat culm 11 on the base end of the burner body 5 so as to be movable in the axial direction.

When the conical body 4 is moved in the axial direction, the gap 3a formed between the inner wall of the trapezoidal hole 3 of the burner body 5 and the conical surface of the conical body 4 changes, and the gap 3a from the air chamber 2 changes.
The amount or flow rate of air advancing toward the combustion chamber 5a through the combustion chamber 5a is adjusted.

A plurality of two types of oil ejection holes 4b and 4c having different diameters are alternately bored in the conical surface of the conical body 4 in the circumferential direction.

A hole with a large diameter is 4b, and a hole with a small diameter is 4c.

The ejection holes 4b and 4c communicate with an oil introduction hole 4a bored in the wheat culm 11.

Further, a swirling blade 6 is attached to the conical surface of the conical body 4.

The height of the swirler 6 in the radial direction may be adjustable.

Air introduced into the air box 2 through the air introduction pipe 1 becomes a swirling flow and advances into the combustion chamber 5a through the gap 3a.

Also, an oil spout hole 4b is formed in the gap 3a. Oil is ejected from 4c, and the air that passes through the narrow gap 3a becomes a swirling flow with high velocity and passes at right angles to the open ends of the ejection holes 4b and 4c, so the oil is atomized according to the principle of atomization.
A uniform mixture of air and oil is sent to the combustion chamber 5a.

The air flow or the mixed gas flow of air and oil is further swirled by the swirl vane and sent to the combustion chamber 5a.

Next, the operation of this oil burner configured as above will be explained.

The swirling airflow within the air box 2 flows into the gap 3a approximately evenly.

Two types of oil ejection holes having different hole diameters, a narrow diameter hole 4b and a small diameter hole 4C, are opened in the gap 3a, and oil is ejected at the same pressure.

Therefore, more oil is ejected from the hole 4b than from the hole 3C, and the mixed gas of air and oil formed near the holes 4b and 4c is a mixed gas with a relatively small air ratio and a mixed gas with a relatively large air ratio, respectively. Become.

Therefore, by adjusting the amount of oil or air introduced into this burner, the air ratio of the mixed gas formed near the ejection holes 4b and 4C can be made to be lower and higher than the stoichiometric air ratio, respectively. In general, the air ratio can be set to the stoichiometric air ratio or a slightly higher air ratio (1.0 to 1.1).

Moreover, by adjusting the width of the gap 3a according to the amount of introduced air, the air flow passing through the ejection holes 4b and 4c can be made high-speed, and the oil can be sufficiently atomized.

These mixed gases are formed alternately in the circumferential direction of the gap 3a, advance into the combustion chamber 5a while swirling within the gap 3a, and are combusted.

That is, two-stage combustion is performed within the combustion chamber 5a.

Moreover, in this oil burner, the oil jet hole 4
The amount of air passing through b and 4c is high speed, and the oil is sufficiently atomized, and the mixed gas flow forms a high speed swirling flow and is blown into the combustion chamber 5a to be combusted, and the gas has a high air ratio. Since the combustion flame of the mixed gas with a high air ratio enters into the center of the combustion flame of the mixed gas with a low air ratio, the generation of soot is kept to a minimum, and the combustion flame of the mixed gas with a low air ratio is kept to a minimum. It is also possible to suppress the generation of NOx and increase combustion efficiency.

Next, the oil burner of the second invention is shown in the fourth diagram of the embodiment.
This will be explained based on the diagram.

The same or corresponding parts as the oil burner in FIG. 2 are indicated by the same reference numerals, and the explanation will be simplified.

In this oil burner, unlike the oil burner shown in FIG. 2, the hole 3 that communicates the combustion chamber 5a and the air chamber 2 in the burner body 5 is a trapezoidal cone whose diameter is tapered from the combustion chamber 5a side. It consists of a first hole and a second trapezoidal hole that is tapered and enlarged in diameter.

Thus, a trapezoidal conical ring 7 having a peripheral surface inclined in the same direction as the throttle hole and a trapezoidal conical hole inclined in the opposite direction is inserted into the second hole portion with the axes aligned. ing.

A plurality of rods 8 are provided protruding from the bottom of the ring 7, and the ring 7 is supported by the rods 8 to be movable in the axial direction at the end of the burner main body 5M.

Therefore, in this burner, the burner gap 3 in FIG.
What corresponds to a is the gap 3a between the inner wall of the burner body 5 and the ring 7.

A conical body 4 corresponding to the conical body 4 in the burner of FIG. 2 is inserted into the trapezoidal hole of the ring 7.

The gap between the ring γ and the conical body 4 is indicated by the reference numeral 7a.

Similarly to the gap 3a, the gap 7a also causes the air in the air box 2a to flow into the combustion chamber 5a at high speed while swirling.

In this burner, the conical body 4 is only provided with a plurality of oil ejection holes 4eL.

The method of supplying oil to the ejection holes 4e is the same as that for the ejection holes 4b and 4c in FIG.

Another kind of plurality of oil ejection holes 4b are provided on the inner wall facing the gap 3a of the burner body 5, and the ejection holes 4b
is communicated with an annular tube 10 wound around the outer peripheral surface of the burner body 5, and the annular tube 10 is communicated with a fuel supply tube 9 connected to an oil supply source.

The oil ejection holes 4d and 4e in this burner are arranged so that the amount of oil ejected is different from the ejection holes 4b and 4c in FIG. 2, that is, the amount of oil ejected from the ejection hole 4e is larger.

For this reason, the diameter of the ejection hole 4e is generally set to be smaller than that of the ejection hole 4d.

However, in this burner, the nozzle 4d. It is also possible to change the air ratio of the mixed gas generated by ejecting oil from the ejection holes 4d and 4e by making the diameter of the holes 4e the same and adjusting the oil feed pressure or the gaps 3a and 7a.

The other construction and operation of this burner is substantially the same as that of the burner of FIG.

However, in the burner shown in Figure 2, the combustion flame of a mixed gas with a high air ratio and the combustion flame of a mixed gas with a low air ratio alternate in the circumferential direction from roughly the same annular zone, creating a swirling flow. However, in this burner, there is a gap 3 on the outside of the combustion flame of the mixed gas with a low air ratio, which spreads conically from the gap 7a and is injected.
Since the combustion flame of the mixed gas having a high air ratio is blown out after being contracted into a conical shape from a, the two flames are effectively mixed in a manner different from that in FIG. 2.

As described in detail above, according to the present invention, the NOx characteristics of the diffusion flame in oil combustion, that is, the characteristics in which the amount of NOx produced is small at low and high air ratios, can be changed, and combustion is performed at both types of air ratios. By intersecting the flames at appropriate positions, it is possible to perform two-stage combustion of oil in a flame with a low air ratio so as to reduce the production of NOx and soot.

[Brief explanation of drawings]

Fig. 1 is a NOx characteristic diagram showing the relationship between air ratio and NOx generation amount, Fig. 2 is a side sectional view showing an embodiment of the oil burner of the present invention, and Fig. 3 is a diagram of a conical body equipped with swirl vanes. Side view,
FIG. 4 is a side sectional view showing another embodiment of the present invention. 1... Air introduction pipe, 2... Air box, 3
...hole, 4 ... cone, 4b, 4
c, 4d, 4e...Ejection hole, 5...Burner body, 5a...Combustion chamber, 6...Swirl blade, 7...・Conical trapezoid ring, 8...
・Rod, 9...Fuel supply pipe, 10...
・Annular tube, 11...Wheat culm.

Claims (1)

[Claims] 1. An air box is formed at the base and a combustion chamber is formed at the tip, and the space between the fuel chamber and the air chamber is tapered from the fuel chamber side to form a trapezoidal cone. It has a cylindrical burner body that communicates with each other through holes, the air chamber has an air introduction pipe that opens in a tangential direction, and the trapezoidal hole has an inclination in the same direction as the throttle hole. A conical body is loaded with its axes aligned, a wheat culm is provided on the conical body protruding from the top in the axial direction, and the conical body can be moved in the axial direction to the base end of the burner body by the wheat culm. A plurality of two types of oil ejection holes with different diameters are opened alternately in the circumferential direction in the cone of the conical body, and the throttle hole is communicated with an oil introduction hole bored in the wheat culm. An oil burner characterized by: 2. The oil burner according to claim 1, wherein a swirling vane for swirling an air flow or a mixed gas flow of air and oil is attached to the conical surface of the conical body. 3. An air chamber is formed at the base, a combustion chamber is formed at the tip, and the space between the combustion chamber and the air chamber is a trapezoidal conical first hole whose diameter is tapered from the combustion chamber side; It has a cylindrical burner body which is communicated by a trapezoidal second hole which is subsequently tapered and enlarged in diameter, the air chamber having a tangentially opening air inlet pipe; A trapezoidal conical ring having a circumferential surface inclined in the same direction as the throttle hole and a trapezoidal conical hole inclined in the opposite direction is inserted into the second hole with its axes aligned, and The trapezoidal ring has a plurality of ronds protruding from the bottom, and the ring is supported by the ronds to be movable in the axial direction at the base end of the burner body. A conical body inclined in the same direction as the hole is inserted with its axis aligned,
The cone has a barley culm protruding from the top in the axial direction,
The conical body is supported for axial movement at the proximal end of the burner body in the wheat culm, and a plurality of oils are disposed at the cone of the conical body and on the inner wall forming the second hole of the burner body. An oil burner characterized in that the ejection holes are open and each ejection hole is communicated with an oil introduction hole bored in the wheat culm and an oil introduction pipe provided on the outer peripheral surface of the burner body.