JPH0619224B2 - Slurry fuel burner - Google Patents

Description

TECHNICAL FIELD The present invention relates to a boiler using slurry fuel as a fuel,
The present invention relates to a combustion burner used in a chemical industrial furnace or the like.

2. Description of the Related Art FIG. 4 shows a conventional burner for burning slurry fuel. In FIG. 4, reference numeral 1 is a burner air box body, and a fuel compartment 2 is arranged in the center thereof. 4 is an auxiliary air compartment, fuel compartment 2
Are located above and below. 5 is a fuel air nozzle, 7 is an auxiliary air nozzle, 8 is a flame stabilizer, and 10 is a burner gun. 12
Is the main air for combustion, the fuel part air pipe 15 and the auxiliary air pipe 17
Branched to. A slurry fuel main pipe 13 is connected to the slurry fuel pipe 18. 14 is a spray medium main, and 20 is a spray medium pipe.
Connected to. 22 is combustion air, 23 is slurry fuel, 24
Is a spray medium, 25 is air in the fuel section, 27 is auxiliary air, and 32 is a flame. 34 is the inside of the furnace, 35 is a damper for adjusting the air flow,
Reference numeral 36 is an atomizer, which are arranged as shown in the drawing to form a burner for burning slurry fuel.

Next, the operation of the burner thus configured will be described.

Combustion air 22 blown through the combustion air main 12 by a ventilation device (not shown) is burner air box body 1
Sent to.

The combustion air 22 sent to the burner air box body 1 is divided into a fuel air 25 and an auxiliary air 27, and the air flow rate adjustment dampers 35 incorporated in the burner air box body 1 respectively set the predetermined flow rates.

The fuel part air 25 is blown into the furnace 34 from the fuel air nozzle 5 provided at the outlet of the fuel compartment 2, and the auxiliary air 27 is supplied from the auxiliary air nozzle 7 provided at the outlet of the auxiliary air compartment 4 to the inside of the furnace. It is blown into 34 and used for combustion.

On the other hand, the slurry fuel 23 is sent to the burner gun 10 provided in the fuel compartment 2 through the slurry fuel main pipe 13 by a slurry fuel supply device (not shown), and reaches the atomizer 36 attached to the tip of the burner gun 10.

The atomizing medium (steam or compressed air) 24 is sent to the burner gun 10 provided in the fuel compartment 2 through the atomizing medium main pipe 14 by an atomizing medium generating device (not shown),
The atomizer 36 attached to the tip of the burner gun 10 is reached.

Slurry fuel 23 and atomizing medium sent to atomizer 36
24 is mixed and injected into the furnace 34, and the fuel air nozzle 5
And the fuel part air 25 and the auxiliary air 27 blown from the auxiliary air nozzle 7 are diffusely mixed and burned to form a flame 32. Combustion near the ignition point of the flame 32 is performed by oxygen in the fuel part air 25. And the subsequent combustion is performed by the oxygen in the auxiliary air 27.

Problems to be Solved by the Invention In the conventional burner for burning slurry, the auxiliary air 27 is mixed with the atomizing medium 24 by the atomizer 36, and the injected slurry fuel is injected.
Since it is blown in close proximity to 23, the flame formed by slurry fuel 23 even if the injection rate of fuel part air 25 is reduced.
Auxiliary air 27 diffuses and mixes rapidly with 32, and hot NO
It had a drawback that an _x (nitrogen oxide) reaction region was formed and the amount of NO _x generated increased.

That is, as shown in FIG. 3, in the relationship between the air ratio (combustion air amount / slurry fuel amount × theoretical air amount) λ and NO _x , when the air ratio λ ≧ 1.0, the air ratio increases. It is generally well known that NO _x tends to rise in proportion.

Means for Solving the Problems In order to solve the steam problem, the present invention divides vertically into three compartments, an excess fuel compartment between the upper lean fuel compartment and the lower auxiliary air compartment. A burner wind box main body in which is disposed, and 60% to 80% of the total slurry fuel is injected into the furnace.
First atomizer attached to the burner gun, and a second atomizer attached to the second burner gun provided in the fuel lean compartment and injecting 20 to 40% of the total slurry fuel into the furnace, and the auxiliary. The air ratio of the flame formed by the first burner gun to the auxiliary air nozzle provided in the air compartment and inclined so as not to face the flame direction by the first atomizer is 0.
There is provided a burner for burning slurry fuel, comprising: 1 to 0.5 and setting means for setting the air ratio of the flame formed by the second burner gun to 0.5 to 1.0.

Action In the above means, the burner wind box body is vertically divided into three compartments, and the fuel compartment is divided into a fuel excess compartment and a fuel lean compartment, and the rest is an auxiliary air compartment. The excess compartment is located above it, with the fuel lean compartment above it, and below it with the auxiliary air compartment. Therefore, the lean fuel compartment and the supplemental air compartment are separated from each other, so that interference between the flame and the supplemental air from the supplementary air compartment due to the fuel lean compartment having a high air ratio is prevented. In addition, for flames from an excess fuel compartment that is adjacent to the supplementary air compartment and is difficult to avoid interference with supplementary air, set the air ratio low and set the supplementary air nozzle of the supplementary air compartment to the supplementary air compartment. By tilting the flame so that it does not point in the direction of the flame, the flame and auxiliary air are diffused and mixed gently.
_It prevents _x from increasing.

Further, the amount of the slurry fuel injected from the first atomizer provided in the excess fuel compartment into the furnace is 60 to 80% of the total slurry fuel, and the first burner gun to which the first atomizer is attached is also provided. The air ratio of the flame formed by is set to 0.1 to 0.5, while the amount of slurry fuel injected from the second atomizer installed in the lean fuel compartment into the furnace is set to 20 to 40% of the total slurry fuel and 2nd with 2 atomizers attached
The air ratio of the flame formed by the burner gun of 0.5 ~
By setting to 1.0, stable combustion, ignition and flame holding can be secured.

Embodiment An embodiment of the present invention will be described in detail below with reference to FIGS. 1 and 2.

FIG. 1 shows an embodiment of a burner for burning slurry fuel according to the present invention, in which 101 is a burner wind box main body,
It is divided into three compartments in the vertical direction, and an excess fuel compartment 102 is arranged between an upper fuel lean compartment 103 and a lower auxiliary air compartment 104. In other words, the excess fuel compartment 102 is arranged in the center of the burner box main body 101, the lean fuel compartment 103 is arranged above it, and the auxiliary air compartment 104 is arranged below it. Each compartment 102, 103, 104 is provided with a fuel excess air nozzle 105 and a fuel lean air nozzle 106 auxiliary air nozzle 107, respectively.

110 is a burner gun of the excess fuel compartment 102, which has an atomizer 136 attached to its tip and a flame stabilizer 108 provided around the tip of the burner gun 110.

111 is a burner gun of the lean fuel compartment 103. An atomizer 137 is attached to the tip of the burner gun, and a flame stabilizer 109 is provided around the tip of the burner gun 111.

The atomizers 136 and 137 are air nozzles 105 and 106, respectively.
It is provided 50 to 150 mm deeper than the tip of and the spray angle is set to 35 ° or less.

Reference numeral 112 is a combustion air main pipe, which is branched into a fuel excess air pipe 115, a fuel lean air pipe 116, and an auxiliary air pipe 117.

Reference numeral 113 is a slurry fuel main pipe, and an excess fuel slurry fuel pipe
118 and a fuel lean portion slurry fuel pipe 119.

Reference numeral 114 denotes a spray medium main pipe, which is branched into a fuel excess portion spray medium pipe 120 and a fuel lean portion spray medium pipe 121.

122 is combustion air, 123 is slurry fuel, 124 is atomizing medium, 125 is excess fuel air, 126 is lean fuel air, 127
Is auxiliary air, 128 is excess fuel slurry fuel, 129 is fuel lean slurry fuel, 130 is excess fuel spray medium, 131
Indicates a fuel lean portion spray medium, 132 indicates a fuel excess portion flame, and 133 indicates a fuel lean portion flame.

Further, 134 is the inside of the furnace, and 135 is a damper for adjusting the air flow, which are arranged as shown in the figure to form a burner for burning slurry fuel.

Next, the operation of the slurry fuel combustion burner according to the present invention thus configured will be described, including setting of the fuel flow rate ratio and air ratio of the atomizers 136 and 137.

Combustion air main 112 by a ventilation device (not shown)
The combustion air 122 sent through the air is divided into excess fuel portion air 125, lean fuel portion air 126 and auxiliary air 127, and the air flow rate adjustment damper 1 built in the burner wind box body 101 is separated.
The predetermined flow rates are set by 35.

The excess fuel air 125 is fed from the excess fuel air nozzle 105 provided at the outlet of the excess fuel compartment 102 to the inside of the furnace 1.
It is blown into 34 and used for combustion, but its flow rate is separately supplied from the burner gun 110 in the excess fuel compartment 102 to the inside of the furnace.
Air ratio to the amount of slurry fuel 128 that is injected into 134 and forms flame 132. Is set to be 0.1 to 0.5.

On the other hand, the fuel-lean air 126 is the fuel-lean compartment.
The fuel-lean air nozzle 106 provided at the outlet of 103 is blown into the furnace 134 for combustion, but the flow rate is separately injected from the burner gun 111 of the fuel-lean compartment 103 into the furnace 134 to cause flame. The air ratio λ _B is set to 0.5 to 1.0 with respect to the amount of slurry fuel 129 forming 133.

Auxiliary air 127 then enters the auxiliary air compartment 10
Inside the furnace from the auxiliary air nozzle 107 installed at the outlet of 4
However, the flow rate is set so that the supply of the fuel excess air 125 and the fuel lean air 126 is insufficient for the combustion of all slurry fuel.

The slurry fuel 123 is supplied to the fuel excess compartment 102 and the fuel lean compartment 10 through the slurry fuel main 113 by a slurry fuel supply device (not shown).
The fuel is supplied to the burner guns 110 and 111 respectively provided in 3 as the excess fuel slurry fuel 128 and the fuel lean slurry fuel 129. And each slurry fuel 128, 129
Reach the atomizers 136 and 137 attached to the tips of the burner guns 110 and 111, and their flow rate is 60 to 80% of the total slurry fuel in the burner gun 110 and burner gun 11
Set 1 to 40 to 20%.

The reason for this is to satisfy the condition that the amount of NO _x generated is small and the unburned loss is small.

That is, FIG. 2 shows the NO _{x in} the burner of the present invention when the ratio Q of the amount of the excess fuel slurry fuel 128 to the amount of the slurry fuel (excess fuel slurry fuel + lean fuel slurry fuel) is variously changed. 2 shows the amount A of generation and the unburned loss B.

As is clear from this figure, when Q is 50% or less, combustion is good and unburned loss is reduced, but it is not suitable because the amount of NO _x generated sharply increases. The ratio is extremely low, which causes deterioration of combustion, which is not suitable. After all, it can be said that the range of Q of 60 to 80% is a suitable range in which combustion is good, unburned loss is small, and the amount of NO _x generated is small.

The atomizing medium (steam or compressed air) 124 is supplied to the burner guns 110 and 111 provided in the fuel-excess compartment 102 and the fuel-lean compartment 103 through the atomizing-medium main pipe 114 by means of an atomizing-medium generator (not shown), respectively. An atomizer that is sent as the fuel lean spray medium 131 and is attached to the tip of each burner gun.
Reach 136 and 137.

Slurry fuel 128 sent to atomizers 136 and 137,
129 and the spray media 130, 131 are mixed and injected into the furnace 134, and the fuel excess air 125 and the fuel lean air 126 are separately blown from the fuel excess air nozzle 105 and the fuel lean air nozzle 106. And diffusively mixes with it and burns to form flame 132 and flame 133. It should be noted that the flames 132 and 133 are firmly fixed near the tips of both the air nozzles 105 and 106 by the flame stabilizer 108 and the flame stabilizer 109 provided on the fuel excess air nozzle 105 and the fuel lean air nozzle 106, respectively. Ignited,
The flame holding of those is secured.

The flames 132 and 133 formed in this way cannot complete combustion only with oxygen in the excess fuel portion air 125 and the lean fuel portion air 126, respectively, so the shortage thereof is supplemented by the auxiliary air nozzle 10
It is supplied by auxiliary air 127 blown from 7 into the furnace 134.

FIG. 3 shows the relationship between NO _x and the air ratio λ.

This FIG. 3 is a generally known relationship diagram, but NO _x
In the region of λ> 1.0, there is a sharp increasing tendency with increasing λ.

As described above, the air ratio λ _B of the flame 133 is set to 0.5 to 1.0, and if interference occurs between the high temperature region of the flame 133 and new air, the air ratio of the flame 133 becomes λ _B > 1.0. The amount of NO _x generated is likely to increase.

However, flame 132 has an air ratio of λ _A = 0.1 compared to flame 133.
It is set as low as ~ 0.5, and there is a margin compared with the flame 133 by the time it reaches the region of λ _A > 1.0.

Therefore, the burner box main body 101 is provided with an excess fuel compartment 102 between the lean fuel compartment 103 and the auxiliary air compartment 104 to avoid interference between the high temperature region of the flame 133 and the auxiliary air 127, and the adjacent compartments. The blowing direction of the auxiliary air nozzle 107 is set to the outward direction (the direction of the anti-flame 132 and the blowing angle θ is, for example, 5 to 30 °) so that the flame 132, which is difficult to avoid interference, does not undergo a rapid diffusion mixing.

The excess fuel air 125 and the lean fuel air 126 are used for combustion from the ignition part of the flames 132 and 133 to the high temperature region, but the excess fuel compartment 102 is arranged between the lean fuel compartment 103 and the auxiliary air compartment 104. As a result, the interference of the high air ratio flame 133 and the auxiliary air 127 can be prevented even if the slight air interference easily increases the NO _x , and the compartment is the auxiliary air compartment 104.
For flames that are in contact with the auxiliary air 127 and it is difficult to avoid interference with them, set the air ratio low and set the auxiliary air nozzle 107 outward (anti-flame 132 direction) to diffuse and mix the flame 132 and the auxiliary air 127. To prevent the increase of NO _x .

Further, the atomizers 136 and 137 and the flame stabilizers 108 and 109 are provided with the fuel excess air nozzle 105 and the fuel lean air nozzle 106, respectively.
It is provided 50 to 150 mm deeper than the tip of. Atomizer 1
The slurry fuel 128, 129 sprayed from 36, 137 is premixed with the air 125, 126 in the respective air nozzles 105, 106 and dried there.

When using a slurry fuel, ceramic is used for at least a part of the atomizer in consideration of wear resistance. By inserting the atomizer in the back of the nozzle, thermal shock is mitigated, and the deterioration of hardness is prevented without being exposed to high temperature.

Set the position of the atomizer 136, 137 to the fuel excess air nozzle 105.
50 to 150 mm from the tip of the fuel lean air nozzle 106
If the atomizing angle of the atomizer is made too large, the slurry fuel collides with the nozzle and causes combustion deterioration due to the internal drawing.

In order for the slurry fuel injected from the atomizer to perform good combustion, it is important that it does not penetrate the air flow ejected from the air nozzles 105 and 106, and for this purpose, the atomization angle of the atomizer 136 and 137 is It is necessary to keep it below a certain value. The maximum atomization angle of this atomizer is 35 °.

As described above in detail, according to the present invention, one burner is provided with two burner guns, two types of flames having different air ratios are formed, and auxiliary air having a larger air ratio is used. Provided is a burner for burning slurry fuel, which is capable of suppressing the generation of NO _x by throwing it away from the flame and further slowing the diffusive mixing of the flame and auxiliary air.

[Brief description of drawings]

FIG. 1 is a system diagram of one embodiment of a burner for slurry fuel combustion according to the present invention, FIG. 2 is a characteristic diagram for explaining the characteristics of the burner according to the present invention, and FIG. 3 is NO _x and air ratio. FIG. 4 is a characteristic diagram for explaining the relationship of the above, and FIG. 4 is a system diagram of a conventional burner for burning slurry fuel. 101 …… Burner box main body, 102 …… Overfuel compartment, 103 …… Fuel lean compartment, 104 …… Auxiliary air compartment, 105 …… Air nozzle over fuel, 106 …… Air nozzle for lean fuel, 107 …… Auxiliary air nozzle, 108,109 …… Flame stabilizer, 110, 111 …… Burner gun, 134 …… Inside furnace, 135 …… Damper for adjusting air flow rate, 136, 13
7 ... Atomizer.

Claims (1)

[Claims] 1. A burner box main body, which is divided into three compartments in a vertical direction, and in which an excess fuel compartment is arranged between an upper lean fuel compartment and a lower auxiliary air compartment, and the burner wind box main body is provided in the excess fuel compartment. The first burner gun installed to inject 60 to 80% of the total slurry fuel into the furnace.
Atomizer, a second atomizer provided in the fuel lean compartment and attached to a second burner gun for injecting 20 to 40% of the total slurry fuel into the furnace, and provided in the auxiliary air compartment. Auxiliary air nozzle inclined by 1 atomizer so as not to face the flame direction, and the air ratio of the flame formed by the first burner gun to 0.1 to 0.5, and the air of the flame formed by the second burner gun. A burner for burning slurry fuel, comprising a setting means for setting the ratio to 0.5 to 1.0.