JP3035564B2 - Oxygen-enriched oil combustion method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for burning oil in an oil burner using oil such as light oil, heavy oil and tar as fuel, and more particularly to an oxygen-enriched oil using oxygen-enriched air as the combustion air. It relates to the combustion method.

[0002]

2. Description of the Related Art In a steel mill, an oil burner using oil such as heavy oil as a fuel is used for heating a ladle or a scouring vessel after discharging molten steel to a high temperature and for cleaning. Oil is cheaper than gaseous fuel, and the cost of equipment required for piping and the like when burning large quantities on an industrial scale is also low.

[0003] When a large amount of oil is burned on an industrial scale, it is general that oil is ejected from the tip of the gun as atomized fine particles by an atomizing medium such as compressed air and water vapor in an oil gun. Here, if the oil spray angle is small, it is difficult to make the spray oil particles finer, and it becomes difficult to perform good combustion and the flame shape deteriorates. Therefore, an oil spray angle of 25 to 55 degrees is often adopted.

[0004] When an object to be heated is heated to a high temperature of 1000 ° C or higher, oxygen-enriched combustion using oxygen-enriched air as combustion air is employed.

[0005]

However, when the oil spray angle of the oil burner is increased, the spray oil particles spread near the burner and the flame becomes shorter. As a result, the burner and its oil gun become hot, and their burnout becomes significant. Further, when the temperature at the tip of the oil gun becomes high, the oil is carbonized and the gun is likely to be clogged.

Particularly, in the case of oxygen-enriched combustion, the flame temperature is high, and such troubles are more likely to occur.

[0007] It is an object of the present invention to provide an oxygen-enriched oil combustion method that solves these problems that occur during oxygen-enriched oil combustion.

[0008]

According to the oxygen-enriched oil combustion method of the present invention, oil is sprayed from an oil gun, the combustion air for the oil is divided into primary air and secondary air, and the primary air is swirled. In the two-stage combustion type oil burner supplied as above, the oxygen amount in the combustion air is 21 to 60%, the ratio of the primary air amount to the total combustion air amount is 60% or less,
The oil spray angle of the oil gun is set to 10 degrees or less.

[0009]

In the oxygen-enriched oil combustion method of the present invention,
A long and stable flame at high temperature can be obtained.

[0010] The amount of oxygen in the combustion air is usually excluded if it is 21% or less, which is the amount of oxygen in the air. If it exceeds 60%, the temperature becomes too high, and the burner itself and the object to be heated may be damaged. Therefore, the content is set to 60% or less.

The ratio of the primary air to the total combustion air amount affects the flame length, and the smaller this ratio is, the longer the flame becomes.

The oil spray angle of the oil gun is
When the combustion air is not enriched with oxygen, stable combustion is performed even at a large angle of 25 degrees or more. However, when using oxygen-enriched combustion air, the temperature needs to be 10 degrees or less for stable combustion.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a vertical sectional side view of an oil burner suitable for carrying out the method of the present invention, and FIG. 2 is a front view of the oil burner.

In FIG. 1, reference numeral 10 denotes a furnace wall of a combustion furnace, 20 denotes a burner tile, 30 denotes a crater formed on the burner tile 20, and 40 denotes a burner body.

The burner tile 20 comprises a first cylindrical body 21 and a second cylindrical body 22 made of a material having excellent heat resistance, and penetrates the furnace wall 10 through a hole 11 provided in the furnace wall 10. Is provided.

A crater portion 30 whose diameter is gradually increased from outside the furnace toward the inside of the furnace is formed inside the first cylindrical body 21. The second cylindrical body 22 is provided concentrically with a slight gap outside the first cylindrical body 21, and the outer peripheral surface thereof is in close contact with the inner peripheral surface of the hole 11. A filler 23 is interposed between the first cylinder 21 and the second cylinder 22. The filler 23 is located at a plurality of positions in the circumferential direction, and forms an air outlet 24 therebetween.

The entrance portion of the crater portion 30 is a wide-angle portion 31 having a large inclination angle with respect to the central axis, and the other portion is a narrow-angle portion 32 having a small inclination angle.

The burner body 40 includes the burner tile 20.
And an oil gun 41 at the center. As shown in FIG. 3, the oil gun 41 supplies oil from the oil inlet 41a into the inner pipe 41b. The oil is mixed with an atomizing medium such as compressed air and water vapor supplied from the atomizing medium inlet 41c into the outer pipe 41d in the mixing chamber 41e, and is provided as fine atomized particles at the tip of the nozzle pipe 41f. Are ejected from the plurality of spray holes 41g. The spray hole 41g faces the center position of the crater part 30,
Oil is sprayed from the crater 30 into the furnace at an angle of 10 degrees or less.

A primary air introduction pipe 42 is fitted on the nozzle pipe 41f of the oil gun 41 with a predetermined gap. A space between the nozzle pipe 41f and the primary air introduction pipe 42 is communicated with the crater 30, and a swirling blade 46 for swirling the primary air is provided between the nozzle pipe 41f and the primary air introduction pipe 42.

The primary air introduction pipe 42 has a secondary air introduction pipe 4
3 are externally fitted with a predetermined gap. A space between the primary air introduction pipe 42 and the secondary air introduction pipe 43 is communicated with the air jet port 24, and a separation plate 44 for dividing combustion air into primary air and secondary air is provided. A valve 4 for adjusting the flow rate distribution between the primary air and the secondary air is provided above the separation plate 44.
5 are provided.

To carry out the method of the present invention using the oil burner, oxygen-enriched air having an oxygen content of 21 to 60% is used as combustion air. Further, oil is sprayed from the oil gun 41 onto the crater 30 at an angle of 10 degrees or less.

The combustion air is divided by a valve 45 into primary air and secondary air so that the ratio of primary air is 60% or less. The primary air is swirled by the swirling blades 46 and is ejected from the crater 30 into the furnace. The primary air collides with the spray oil to rapidly mix and burn the oil, and the heat of combustion promotes gasification and decomposition of the oil. .

When the fuel is a flame-retardant heavy oil such as tar, it is more preferable to provide the crater portion 30 with the wide-angle portion 31 and the narrow-angle portion 32. It passes through the corners 32 in order. Since the front narrow-angle portion 32 has a smaller inclination angle than the rear wide-angle portion 31, the combustion gas flows through the wide-angle portion 3.
Stay at one. Due to this stagnation, the crater 3 of the swirled fuel
The adhesion to the 0 wall is prevented, and the combustion is stably continued.
The angle of the wide-angle part 31 is 20 to 90 degrees, the angle of the narrow-angle part 32 is 30 degrees or less, and it is desirable that the angle of the wide-angle part 31 is 5/8 to 7/8.

On the other hand, the secondary air is jetted directly from the air jet port 24 into the furnace. Here, the air outlet 24 is closed at a plurality of locations in the circumferential direction by the filler 23. Therefore, the secondary air blown out from the furnace is in a state of being divided in the circumferential direction, and the high heat inside the furnace is introduced into the secondary air flow through the divided part, that is, the low-pressure part corresponding to the position where the filler 23 is disposed. Gas flows in and promotes thermal decomposition and gasification of the oil. Note that the filler 23 is made up of the first cylinder 21 and the second cylinder 2.
Instead of interposing the gap 2 in a manner to close it, the gap may be interposed in a manner to narrow the gap. In this case, the air outlet 24 is a series of existing products in which the opening area is reduced at a plurality of locations in the circumferential direction. Are formed.

FIG. 4 is a graph showing the relationship between the ratio of the primary air amount to the total combustion air amount and the flame length when oxygen-enriched oil combustion was performed under the conditions shown in Table 1. When the ratio of the primary air amount is 60% or less, long flame is achieved. However, if the amount of primary air is extremely reduced, especially for heavy oil such as tar, the mixed gas of primary air and spray oil becomes insufficient, and ignition stability deteriorates. Therefore, the ratio of primary air volume is 15%
The above is desirable.

[0027]

[Table 1]

FIG. 5 is a graph showing the combustion stability when the amount of oxygen in the combustion air and the oil spray angle are changed using the same A fuel as in FIG. When using oxygen-enriched combustion air, it is better to reduce the oil spray angle, and when it is 10 degrees or less, stable combustion with less oil gun clogging and oil adhesion to burner tiles is performed. This is because the flame is lengthened by reducing the oil spray angle, and the heating of the burner, particularly the heating of the tip of the oil gun, is suppressed. Further, even if the oil spray angle is reduced, the atomization of oil and the flame shape are not particularly deteriorated. This is because the primary air is given a strong swirl so that the mixing property is good. Further, in this embodiment, the filler 23 is provided in the secondary air ejection port 24, Another reason is that high-temperature gas flows into the furnace, which promotes thermal decomposition and gasification of oil.

[0029]

As is apparent from the above description, the oxygen-enriched oil combustion method of the present invention regulates the oxygen content by defining the ratio of the primary air amount to the total combustion air and the oil spray angle in the oil gun. Despite the enriched oil combustion, the heating temperature of the burner is suppressed to prevent burning of the burner and blockage of the oil gun due to carbonization of the oil, thereby improving the durability of the burner and stabilizing the combustion.

[Brief description of the drawings]

FIG. 1 is a longitudinal side view of an oil burner suitable for carrying out the method of the present invention.

FIG. 2 is a front view of the oil burner.

FIG. 3 is a side view of an oil gun provided in the oil burner.

FIG. 4 is a graph showing a relationship between a ratio of a primary air amount to a total combustion air amount and a flame length.

FIG. 5 is a graph showing the influence of the amount of oxygen in combustion air and the oil spray angle on combustion stability.

[Explanation of symbols]

 Reference Signs List 10 furnace wall 20 burner tile 30 crater part 40 burner body 41 oil gun

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tadayuki Taniguchi 111-1 Showa-cho, Kure-shi, Hiroshima Nisshin Steel Corporation Kure Works (72) Inventor Masaaki Fujio 1 Tsurumachi, Amagasaki-shi, Hyogo Nisshin Steel (56) References JP-A-3-191201 (JP, A) JP-A-3-31604 (JP, A) JP-A-2-302505 (JP, A) JP-A-63-187011 ( JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23D 11/24 F23C 11/00 ZAB

Claims (1)

(57) [Claims] 1. A two-stage combustion type oil burner which sprays oil from an oil gun, divides the combustion air of the oil into primary air and secondary air, and imparts a swirl to the primary air to supply the combustion air. 21-60% of the amount of oxygen in the
An oxygen-enriched oil combustion method, wherein a ratio of a primary air amount to a total combustion air amount is 60% or less, and an oil spray angle of an oil gun is 10 degrees or less.