JP2003302011A - Burner with nozzles for different average particle sizes of fuel to be sprayed - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure spray burner for controlling the amount of combustion with less amount of generation of NOx and less amount of generation of unburnt gas. <P>SOLUTION: The pressure spray burner in which a pressure fuel oil supplied to fuel spray nozzles is sprayed from the fuel spray nozzles for combustion comprises a low combustion nozzle 4 and a high combustion nozzle 5 provided as the fuel spray nozzles. High combustion is established by using a fuel sprayed from both the low combustion nozzle 4 and the high combustion nozzle 5 in combustion while low combustion is established by using the fuel sprayed only from the low combustion nozzle 4 in combustion. The average particle size of the fuel oil sprayed from the high combustion nozzle 5 is larger than the average particle size of the fuel oil sprayed from the low combustion nozzle 4. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a burner provided with a plurality of nozzles having different atomized fuel particles.

[0002]

2. Description of the Related Art There is a pressure spray burner which supplies pressurized fuel oil to a fuel spray nozzle and sprays the fuel oil from the fuel spray nozzle for combustion. In the burner, when the combustion amount at the time of combustion is in two stages of low combustion and high combustion, a low combustion nozzle and a high combustion nozzle are provided as fuel spray nozzles, and at the time of low combustion, the fuel is supplied only from the low combustion nozzle. Is sprayed to perform combustion, and in the case of high combustion, the fuel spray amount is adjusted by spraying fuel from both the low combustion nozzle and the high combustion nozzle.

Further, the supply amount of combustion air is also adjusted according to the combustion amount, and the supply amount of combustion air is reduced when the combustion is low, and the supply amount of combustion air is increased when the combustion is high. At this time, since the opening area of the combustion air supply unit is constant regardless of the combustion amount, the flow velocity of air increases when the supply amount of combustion air increases, and the flow velocity decreases when the supply amount of combustion air decreases. When the flow velocity of air increases, the mixing property of fuel and air improves, and vaporization and combustion are promoted.Therefore, high combustion causes intensive combustion in a short time, and low combustion causes slow combustion. Become.

When the amount of combustion increases, the flame temperature rises due to an increase in heat load, and intensive combustion is performed in a shorter time, so that a local high temperature region occurs and NO
The x generation amount tends to increase. On the other hand, if the amount of fuel decreases, the flame temperature will decrease due to the decrease in heat load, and combustion will be slower.Therefore, the flame temperature will decrease before combustion is complete and the combustion reaction will stop, resulting in unburned fuel. Minutes are generated, and the amount of smoke and CO generated tends to increase. In the case of high combustion, the amount of unburned components is small, but the amount of NOx generated is large, and conversely, in the case of low combustion, there is a tendency that the amount of unburned components is small but the amount of NOx is small. In a burner in which the combustion amount is in two stages, low combustion and high combustion, it is necessary to set the combustion state so as to balance NOx suppression during high combustion and unburned content suppression during low combustion.

The time required for burning the sprayed fuel can be adjusted by the particle size of the fuel sprayed from the fuel spray nozzle. If the average particle size of the fuel oil sprayed by the fuel spray nozzle is reduced, the mixing property of fuel and air is improved, and the time required for vaporization and combustion is shortened, so that the time required for flame combustion is shortened. On the contrary, if the average particle size of the sprayed fuel oil is increased, the mixing property of the fuel and the air is deteriorated, and the time required for burning the flame becomes longer.

If the setting for slowing the progress of combustion is made to reduce the NOx generation amount in the high combustion, the unburned amount generation amount is increased in the low combustion and the unburned amount generation amount is decreased in the low combustion. If the setting is made so that the combustion progresses rapidly, there is a trade-off relationship that the amount of NOx generated will increase in high combustion, so the amount of NOx generated during high combustion will be reduced, and the unburned content during low combustion will be reduced. It was not possible to reduce the amount generated.

[0007]

The problem to be solved by the present invention is to reduce the NOx generation amount and the unburned matter generation amount in a pressure spray burner for adjusting the combustion amount.

[0008]

The invention according to claim 1 is a pressure spray burner for supplying pressurized fuel oil to a fuel spray nozzle and spraying the fuel oil from the fuel spray nozzle for combustion. , A low combustion nozzle and a high combustion nozzle are provided as fuel spray nozzles, and high combustion in which fuel is sprayed from both the low combustion nozzle and the high combustion nozzle,
The average particle size of the fuel oil sprayed from the low combustion nozzle is the average particle size of the fuel oil sprayed from the high combustion nozzle in a pressure spray burner that sprays fuel only from the low combustion nozzle and burns. It is characterized by making it larger than.

According to a second aspect of the invention, in the burner provided with a plurality of nozzles having different average particle diameters of the atomized fuel, the pressure of the fuel oil supplied to the high combustion nozzle is supplied to the low combustion nozzle. By lowering the pressure of the fuel oil to be used, the average particle size of the fuel oil sprayed from the high combustion nozzle is
It is characterized in that it is made larger than the average particle size of the fuel oil sprayed from the low combustion nozzle.

According to a third aspect of the present invention, in the burner having a plurality of nozzles having different average particle diameters of the atomized fuel, the orifice is provided in the middle of the high combustion fuel supply passage for supplying the fuel to the high combustion nozzle. By setting the pressure of the fuel oil supplied to the high combustion nozzle to be lower than the pressure of the fuel oil supplied to the low combustion nozzle, the average particle size of the fuel oil sprayed from the high combustion nozzle can be reduced. It is characterized in that it is made larger than the average particle size of the fuel oil sprayed from the use nozzle.

When the average particle size of the fuel oil sprayed from the high combustion nozzle is larger than the average particle size of the fuel oil sprayed from the low combustion nozzle, the average particle size of the atomized fuel at the time of high combustion is the spray at the time of low combustion. It is larger than the average particle size of the fuel. In the case of high combustion, the time required for combustion is short in that the flow velocity of combustion air is high, and the time required for combustion is long in that the average particle size of fuel oil is large. On the other hand, in the case of low combustion, the time required for combustion is long in that the flow velocity of the combustion air is slow, and the time required for combustion is short in that the average particle size of the fuel oil is small. By making the average particle size of the atomized fuel different depending on the amount of combustion, combustion at high combustion can be slowed and combustibility at low combustion can be improved. The amount of NOx generated during high combustion can be reduced without increasing the amount of NOx, and the amount of unburned components generated during low combustion can be reduced without increasing the amount of NOx generated during high combustion.

[0012]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described with reference to the drawings. 1 and 2 are flow charts of a burner embodying the present invention. FIG. 1 shows a case of high combustion and FIG. 2 shows a case of low combustion. The burner is provided in the upper part of the combustion chamber 12 and generates a flame downward toward the combustion chamber 12. Inside the burner, a low combustion nozzle 4 and a high combustion nozzle 5 for spraying fuel oil toward the combustion chamber 12 are provided. The fuel supply path 2 for supplying fuel to the low-combustion nozzle 4 and the high-combustion nozzle 5 is branched into a low-combustion fuel supply path 6 and a high-combustion fuel supply path 7 on the way. A low combustion fuel supply passage 6 is connected to the high combustion nozzle 5, and a high combustion fuel supply passage 7 is connected to the high combustion nozzle 5. An oil pump 3 is provided on the upstream side of the branch portion of the fuel supply passage 2, a low combustion fuel valve 8 is provided in the middle of the low combustion fuel supply passage 6, and a high combustion fuel valve is provided in the middle of the high combustion fuel supply passage 7. 9 is provided, and the orifice 1 is provided on the downstream side of the high combustion fuel valve 9 in the high combustion fuel supply passage 7. Further, a blower 10 for supplying combustion air to the combustion chamber 12 is provided, and the opening of the damper is changed in the middle of the air passage connecting the blower 10 and the combustion chamber 12 to change the combustion air to the combustion chamber 12. An air volume adjusting device 11 for adjusting the supply amount is provided.

When performing high combustion, both the low combustion fuel valve 8 and the high combustion fuel valve 9 are opened, and the oil pump 3
The fuel oil pressurized by is sent to the low combustion nozzle 4 and the high combustion nozzle 5. By supplying the fuel oil pressurized by the oil pump 3, a pressure difference is generated between the low combustion fuel supply passage 6 and the high combustion fuel supply passage 7 and the combustion chamber 12, so that the low combustion nozzle 4 And the fuel oil that has reached the high combustion nozzle 5,
It becomes fine particles and is sprayed into the combustion chamber 12.

The oil pump 3 is shared by the low combustion nozzle 4 and the high combustion nozzle 5, and the fuel oil passes through the low combustion fuel supply passage 6 and the high combustion fuel supply passage 7 and is connected to each of them. Toward the low combustion nozzle 4 and the high combustion nozzle 5. The pressure of the fuel oil after being pressurized by the oil pump 3 is
There is no difference between the low-combustion nozzle 4 and the high-combustion nozzle 5 but the pressure drops when passing through the low-combustion fuel supply passage 6 or the high-combustion fuel supply passage 7.
At this time, since the orifice 1 is provided in the high combustion fuel supply passage 7 and the pressure loss occurs in the orifice 1, the pressure drop in the high combustion fuel supply passage 7 is smaller than that in the low combustion fuel supply passage 6. The pressure drop is larger. For example, the oil pressure immediately after the oil pump 3 is 0.15 MPa, and the oil pressure at the low combustion nozzle 4 after passing through the low combustion fuel supply passage 6 is 0.10 MPa.
In this case, the hydraulic pressure in the high combustion nozzle 5 after passing through the high combustion fuel supply passage 7 is 0.07 MPa.

Since the pressure of the fuel supplied to the low combustion nozzle 4 is relatively high, the fuel oil passing through the low combustion nozzle 4 has a strong momentum, and the average fuel oil sprayed from the low combustion nozzle 4 is average. The particle size becomes smaller. On the other hand, the pressure of the fuel supplied to the high-combustion nozzle 5 is relatively low, and the fuel oil passing through the high-combustion nozzle 5 loses its momentum when the pressure becomes low. The average particle size of the fuel oil is increased.

In the case of high combustion, combustion is performed with the fuel sprayed from both the low combustion nozzle 4 and the high combustion nozzle 5,
The average particle size of the fuel oil during high combustion is the low combustion nozzle 4
Is larger than the average particle size of the fuel oil. When the average particle size of the fuel oil becomes large, it takes time to vaporize the fuel oil, so that the combustion of the sprayed fuel oil is suppressed, and the combustion is slow.

Further, the air volume adjusting device 11 is set to a high combustion opening, and the blower 10 sends the combustion air having a high air volume for combustion to the combustion chamber 12. Since the opening area of the portion where the combustion air is blown into the combustion chamber 12 is constant regardless of the amount of combustion,
If the amount of air for high combustion is large, the flow velocity of the air injected into the combustion chamber 12 will be high. When the flow velocity of the combustion air injected into the combustion chamber 12 is increased, the mixing property of the fuel and the air is improved, the combustion of the spray fuel oil is promoted, and the combustion speed is increased.

In the case of the conventional high combustion, the average particle size of the sprayed fuel oil is the same as that in the case of the low combustion, and the combustion is promoted only by the fact that the combustion air is accelerated by the high flow velocity of the combustion air. The process proceeded intensively over time, a local high temperature region was generated, and the amount of NOx generated was large. However, by making the average particle size of fuel oil during high combustion larger than that during low combustion, the effect of suppressing combustion occurs, and combustion becomes slower than in the past, so local high temperature regions occur. Therefore, the NOx generation amount can be reduced.

When performing low combustion, only the low combustion fuel valve 8 is left open, and combustion is performed only with the fuel sprayed from the low combustion nozzle 4. Orifice 1 in the low combustion fuel supply path 6
Is not provided, the pressure of the fuel supplied to the low combustion nozzle 4 is relatively high, the fuel oil passing through the low combustion nozzle 4 has a strong momentum, and the fuel oil sprayed from the low combustion nozzle 4 is The average particle size becomes smaller.

In the case of low combustion, combustion is performed only with the fuel sprayed from the low combustion nozzle 4, so that the average particle size of fuel oil during low combustion is smaller than that during high combustion. When the average particle size of the fuel oil is small, the time required for vaporization of the fuel oil is short, so that the combustion of the atomized fuel oil is promoted and the combustion speed is increased.

Further, the air volume adjusting device 11 is set to an opening for low combustion, and the blower 10 sends combustion air having a low air volume for combustion to the combustion chamber 12. Since the opening area of the portion where the combustion air is blown into the combustion chamber 12 is constant regardless of the combustion amount, if the low combustion air volume with a small air volume is used, the combustion chamber 12
The flow velocity of the air injected into is slow. When the flow velocity of the combustion air injected into the combustion chamber 12 becomes low, the mixing property of the fuel and the air deteriorates, so that the combustion of the spray fuel oil is suppressed and the slow combustion is performed.

By providing the orifice 1 in the high combustion fuel supply passage 7, the pressure of the fuel oil sent to the high combustion nozzle 5 is adjusted so that the average particle size of the sprayed fuel oil during high combustion is lower than that during low combustion. Since the pressure is increased, it is possible to increase the pressure of the fuel oil sent to the low combustion nozzle 4 without increasing the pressure of the fuel oil sent to the high combustion nozzle 5. By increasing the pressure of the fuel oil by the oil pump 3 and increasing the fuel oil pressure in the low combustion nozzle 4, the average particle size of the fuel oil sprayed from the low combustion nozzle can be reduced, resulting in low combustion. It is possible to suppress the generation of unburned components in time.

[0023]

By implementing the present invention, it is possible to reduce the amount of NOx generated during high combustion and the amount of unburned matter generated during low combustion. Both can be reduced.

[Brief description of drawings]

FIG. 1 is a flow chart at the time of high combustion of a burner implementing the present invention.

FIG. 2 is a flow chart of the burner embodying the present invention during low combustion.

[Explanation of symbols]

1 orifice 2 Fuel supply path 3 oil pump 4 Low combustion nozzle 5 High combustion nozzle 6 Low combustion fuel supply path 7 High combustion fuel supply path 8 Fuel valve for low combustion 9 Fuel valve for high combustion 10 blower 11 Air flow controller 12 Combustion chamber

Claims (3)

[Claims] 1. A pressure spray burner for supplying pressurized fuel oil to a fuel spray nozzle and spraying the fuel oil from the fuel spray nozzle for combustion, wherein a low combustion nozzle and a high combustion nozzle are used as the fuel spray nozzle. In a pressure spray burner that is provided with a nozzle and performs high combustion in which fuel is sprayed from both the low combustion nozzle and the high combustion nozzle, and low combustion in which fuel is sprayed and burned only from the low combustion nozzle, Equipped with a plurality of nozzles with different average particle size of the sprayed fuel, characterized in that the average particle size of the fuel oil sprayed from the high combustion nozzle is made larger than the average particle size of the fuel oil sprayed from the low combustion nozzle Burner. 2. A burner comprising a plurality of nozzles having different average particle diameters of the atomized fuel according to claim 1, wherein the fuel oil pressure supplied to the high combustion nozzle is the fuel oil pressure supplied to the low combustion nozzle. The average particle size of the fuel oil sprayed from the high combustion nozzle is made larger than the average particle size of the fuel oil sprayed from the low combustion nozzle by lowering the pressure of Burner with multiple nozzles with different particle sizes. 3. A burner having a plurality of nozzles having different average particle sizes of sprayed fuel according to claim 1, wherein an orifice is provided in the middle of a high combustion fuel supply passage for supplying fuel to the high combustion nozzle. By making the pressure of fuel oil supplied to the high combustion nozzle lower than the pressure of fuel oil supplied to the low combustion nozzle, the average particle size of the fuel oil sprayed from the high combustion nozzle can be reduced A burner provided with a plurality of nozzles having different average particle sizes of the sprayed fuel, characterized in that the average particle size of the fuel oil sprayed from is larger.