JPS58224205A - Burner with mechanism for reducing unburnt content at outlet of furnace - Google Patents

Abstract

PURPOSE:To reduce a quantity of a high level CO produced at the vicinity of a side wall and at a corner part, by a method wherein small auxiliary OA ports are formed, being positioned closer to a side wall than an outermost burner row, and OA ports in a combustion mechanism take the form of a turnable circular type. CONSTITUTION:Small auxiliary OA ports 24, being different in a swhirling direction from that of other OA ports 23, are formed in parallel at two corners in the vicinity of the side wall of a furnace. Namely, a clockwise swirling stream is produced in an air current at a burner part and an air current in conventional OA ports so that the air currents bend leftwardly, and meanwhile a counterclockwise swirling stream is produced in the air stream at the auxiliary port so that it bends rightwardly. This enables to promote the supply of the air to the vicinity of a side wall and corner parts where a high level CO is present and to reduce a quantity of CO produced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides nitrogen
The present invention relates to a combustion apparatus with a 1" unburned content reduction mechanism for low-fired furnaces that reduces the high concentration of CO near the side walls, which is a problem in boilers that have taken measures to reduce Ox.

In boilers with NOx reduction measures such as two-stage combustion or in-furnace denitrification combustion, air-deficient combustion is performed in the area O of the burner 2 of the furnace 1 having the wind box 10, with reference to FIG. By raising the engine and supplying insufficient air from the OA boat 6, NOx is reduced and complete combustion is achieved. However, it occurs in the burner area because there is an imbalance in the amount of air supplied from the OA boat, or because the air and combustion gas are not mixed sufficiently in the furnace. There was a tendency for the temperature to reach a high (:0 level) at the furnace outlet without being completely burnt. Analysis of the cause of this revealed that the temperature was particularly high near the side walls and at the corners.

Hereinafter, the problems of the prior art will be specifically explained using two examples of conventional boiler plants.

FIGS. 2 and 4 are perspective explanatory views showing the arrangement of burners and OA boats in conventional boiler plants of a first example and a second example, respectively. , code 1 is the furnace,
6 indicates the burner, 6 indicates the OA port, and arc-shaped arrow 9Q indicates the turning direction. As can be seen, both OA boats are installed in the same row as the top burner.

Fig. 6 (a, b) and Fig. 5 (a, b) show the conventional energy saving device (hereinafter abbreviated as VCO) outlet (in Fig. 1) of the first example and the second example of the plant, respectively. It is a distribution map showing the distribution of Co concentration at a location corresponding to the lower part of the can extending to the right. Figure 6 In Figure 5, areas where dense hatching has been applied are areas where the Co concentration is high, areas where rough hatching has been applied are areas where the Co concentration is medium, and areas where no nodding has been applied. The portions indicate portions where the Co concentration is low. In either case, the flow from the furnace (upper part of the left can part in Figure 1) to the ECO outlet ((lower part of the right can part in Figure 1) is considered to be laminar flow, and the 00 distribution at the furnace outlet is In front of the 1L can, the can diameter is reversed and it is ECO.
It is assumed that the exit will be 00 distribution.

What can be said in common in both the conventional plants of the first example and the second example is that the Co concentration is high near the side walls and in the corner portions (the densely hatched portions in the figure).

The cause of this problem will be explained below with reference to FIGS. 4 to 8 for a second conventional example.

In these drawings, 1 is a furnace, 6 is a burner, and 6 is a burner.
indicates the OA port, arcuate arrow 9 indicates the turning direction, 11 indicates the flame shape, 12 indicates the burner, and 31.62 indicates the air shortage region.

- In an OA boat, an air register gives a swirl to the air flow for the purpose of promoting flame stability and mixing of air and flame, and in an OA boat, a swirl is given to the air flow for the purpose of promoting mixing of air and combustion gas. These swirling flows, as shown in the schematic diagram of Fig.
According to Toukoski's law, a horizontal force is obtained, and the right-handed swirling flow curves to the left, and the left-handed swirling flow curves to the right. This has been confirmed through a five-dimensional water flow model test conducted by the inventors.

In FIG. 4, the air flow swirling directions in the burner section and the OA port section are shown by arcuate arrows 9, and all of them are clockwise. At the bottom, the flame (Figure 6, number 11) and the OA boat airflow (Figure 7, number 12) turn to the left. As a result, areas where air supply is insufficient appear near the side walls of the OA boat and at the corners (Figure 7, 62° shaded area). Therefore, the CO in the vicinity of the side wall and the corner portion (Figure 6, shaded portion at 61°) of the no;-suna 15 is not completely combusted and remains at a high level (:0).

That is, the conventional technology as a CO reduction measure has a problem in that the design or structure does not take into account the change in the swirling air flow due to the ascending gas flow.

The purpose of the present invention is to overcome the above-mentioned drawbacks of the prior art, namely:
It is an object of the present invention to provide a combustion apparatus having a furnace outlet unburned content reduction mechanism using an improved OA port mechanism, which can reduce high level CO1 in the vicinity of the side walls and corners of a boiler plant.

The characteristics of the combustion apparatus having an unburned content reduction mechanism at the furnace outlet of the present invention are that the combustion apparatus performs two-stage combustion and in-furnace denitrification combustion, and has an OA boat, and an OA boat that performs complete combustion. In order to make full use of the functions of the boat, a small auxiliary OA boat is placed closer to the side wall than the burner row at the end, and a combustion mechanism is provided to improve the supply of air to the vicinity of the side wall. The OA boat in the combustion mechanism will be of a rotatable Zakira type, so that the direction of the airflow caused by it can be adjusted. In this case, it is preferable that the area of the small auxiliary OA boat is the same as that of the OA boat placed directly above the burner.

That is, the present invention provides a Zakira-type small OA boat between the side wall of the boiler plant where the amount of air from the OA is insufficient and the burner row closest to this, and By giving a turning direction, it promotes the supply and mixing of air to the corners and side walls, and C
This is designed to reduce the O level.

Below, the present invention will be described in detail in Section 9.10.11.1.
This will be explained in more detail with reference to FIG.

Figures 9 to 11 show OA based on the basic idea of the present invention.
Figure 12 shows the arrangement and rotation direction of the OA boat supply nozzle, the direction of rotation, and the shape of the flame and air flow inside the furnace. , 1 is a furnace, 5 is a water cooling wall, 6 is an air register, 7 is a plug, 8 is a throat part, 9 is a rotating direction, and 10
is the wind box, 21 is the air flow, 22 is the burner flame and its flow, 26 is the OA boat and its flow, 24 is the auxiliary OA
Showing the boat and its current.

In this embodiment, the perspective explanatory view of the entire can part shown in FIG. 9,
A view taken along line C-C in Figure 9, and a view taken along line D-1 in Figure 10 and Figure 9, which particularly shows the condition of the burner flame, particularly for OA boats and small auxiliary OA boats. As shown in Figure 11, which shows the condition,
Regarding the burners, as shown in FIG.
The burners are arranged in rows, and the flame core axes of the burners at the front and rear of the can are not on the same axis, and the flame cores are offset from each other. I)-
1) As clearly shown in the diagram, small auxiliary OA ports 24 are installed at two corners near the side wall of the furnace, each with a different turning direction from those in the other 6A boats 23. That is, the burner section (tertiary) air flow (see arrow 22 in FIG. 10) and the conventional OA boat air flow (see arrow 26 in FIG. 11). ) is given a right turn so that it bends to the left, while the auxiliary OA boat airflow is given a left turn and made to bend to the right (as shown by the arrow 24 in Figure 11). (see). This makes it possible to reduce CO by promoting the supply of air to the areas near the side walls and corners (see the shaded area in Figure 7 above) where CO levels are high, which was a problem with the prior art. This is what I did.

In the embodiment described above, as shown in FIG. 11, the small auxiliary OA boat 24 is provided only near the wall on one side of the row of OA ports. Installed near the wall on both sides of the row of ports,
For example, in Fig. 11, the number of small auxiliary OA ports 24 is increased from two to four, and by adjusting each small auxiliary OA port 24, mutual communication over the entire area is improved compared to the case of one on each moving side. It is possible to improve the layer effect due to the compatibility between the two, and it goes without saying that the addition of a small auxiliary OA port in this way also falls within the scope of the present invention.

Returning to the explanation of this embodiment, in this embodiment, the 12th
As shown in the figure, the air in the wind box 10 is given a swirl by the air register B, and is supplied to the furnace 1 through the throat section 8. - By adjusting the turning strength by air register B, the degree of curvature (direction) of the airflow can be adjusted. By moving the plug 7 back and forth in its position and adjusting the cross-sectional area through which the air passes through the throat portion 8, the air penetration force can be varied. That is, when the plug 7 is pushed out toward the furnace side, the throat portion becomes narrower, the air flow rate increases, and the distance within the furnace becomes longer. Conversely, when you pull it back, the throat part 8 becomes wider,
The air velocity decreases and the distance traveled becomes shorter. All OAs
If a supply nozzle with a plug as shown in FIG. 12 is used on the boat, the direction of the air flow can be adjusted by changing the swirling strength with the air register 6, and the penetration force can be adjusted by displacing the position of the plug 7. This makes it possible to supply and mix air appropriately, thereby achieving even greater CO reduction.

In contrast to the above-described embodiments of the present invention, there is a known one in which an auxiliary OA port called a side OA boat is provided to reduce CO near the side wall. It is a parallel flow without swirling, so there is no curvature of the flow, and the air flow on the side wall is the same size as the one that can be taken in the burner core, so it is not necessary to use a small auxiliary OA as in the embodiment of this application. It is not a boat, has a different structure and function, and cannot provide the effects as in this embodiment.

As explained above, the device of the present invention has significant effects, and the effects of the present invention can be summarized as follows.

1) High level/lCO in the furnace corners and near the side walls
It has a great effect on reducing

11) Since air is supplied to the corners and near the side walls without changing the mixing strength due to swirling, CO2 caused by mixing is reduced.
The reduction effect is maintained.

l11) Relatively simple changes such as installing an auxiliary OA port and improving the rotation can produce a large CO reduction effect.
do.

1v) By combining with a flow rate adjustment plug, an even greater CO reduction effect can be achieved.

■) The above CO reduction effect contributes to low pollution and energy conservation.

[Brief explanation of the drawing]

FIG. 1 is an explanatory side view of the boiler, showing the burner and OA port. Fig. 2 is a perspective explanatory view showing the arrangement and rotation direction of burners and OA ports in a boiler of a conventional example (first example), and Figs. (ECO) This is a CO concentration distribution map of the cap stone on the left side of the can outlet. FIG. 4 is a perspective explanatory view showing the arrangement and rotation direction of burners and OA ports in a boiler of another conventional example (second example), and FIG. This is a CO concentration distribution map of the capstone on the left side of the can at the exit of the charcoal maker (ECO). Figures 6 and 7 show the flame shape (A-A parent diagram) and air flow shape (A-A parent diagram) in Figure 4, respectively. 13-13 view), and FIG. 8 is a reproduction explanatory diagram of the behavior of the swirling flow in the double-rising gas flow. FIG. 9 shows Nocuna and O in the boiler according to the embodiment of the present invention.
This is a perspective explanatory diagram showing the arrangement and turning direction of the A boat and the auxiliary OA boat.
-C parent diagram, and FIG. 11 is an I)-1) parent diagram based on line 1)-1) of FIG. 9, and FIG. 12 shows the structure of the OA port supply nozzle in the embodiment of the present invention. FIG. 1...Furnace 2.2'...Burner...
, OA boat 5... Water cooling wall 6... Air register 7... Plug 8... Throat part
9... Turning direction 10... Wind box 11...
- Flame shape 12... Over air shape 21 Air flow 22... Burner and its flow 23... OA port and its flow 24... Auxiliary OA boat and its flow 60... Burner area 61,62... Air Deficiency Area Patent Attorney Junnosuke Nakatoshi 'Iv2 Diagram, 13 Diagram'?4 Diagram/Fuji 1F6 Diagram IP7 Diagram IP8 Diagram

Claims (4)

[Claims] (1) In combustion equipment that performs two-stage combustion or in-furnace denitrification combustion and has an OA boat, to ensure complete combustion and to fully utilize the function of the OA port.
A small auxiliary OA boat is arranged closer to the side wall than the burner row at the end, and a combustion mechanism is provided to improve the supply of air to the vicinity of the side wall, and the OA boat in the combustion mechanism can be rotated. 1. A combustion device having a mechanism for reducing unburned matter at a furnace outlet, characterized in that the mechanism is shaped like a U-shape so that the direction of airflow can be adjusted. (2) A combustion apparatus having an unburned content reduction mechanism at a furnace outlet according to claim 1, wherein the OA boat is rotatable, variable in air flow direction, and provided with a plug having a variable air passage cross-sectional area. . (3) The direction of the air flow in the small auxiliary OA boat is as follows:
1] A combustion apparatus for a furnace having an unburned content reduction mechanism according to claim 2, which causes the air flow in the other OA ports to flow in the opposite direction. (4) The area of the small auxiliary OA boat is the same as or 1/4 of the area of the OA boat installed directly above the burner. A combustion device having an unburned content reduction mechanism at the furnace outlet according to the above.