JP2000193225A - Combustion device for exhaust gas including dust - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a combustion device for an exhaust gas including dust for stably burning a stabilizing burner and avoiding a dust trouble or the like. SOLUTION: In a combustion device for an exhaust gas including dust, an exhaust gas introducing port 5 for introducing the exhaust gas to be burnt into a combustion chamber 2 in a furnace is provided in the upstream side of the furnace, an exhaust port 4 is provided in the downstream side of the furnace and assist burners 6 and 12 are provided in the intermediate parts of the furnace. The assist burners are provided at installation angles θ1 and θ2 relative to the upstream side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dust-containing exhaust gas combustion treatment apparatus.

[0002]

2. Description of the Related Art Dust-containing exhaust gas generated when industrial waste or the like is incinerated in an incinerator usually contains combustible substances. A combustion burner is used to burn this exhaust gas in the combustion processing device.

As such an apparatus, for example, an apparatus as shown in FIG. 2 of the accompanying drawings is known.

FIG. 2 shows a vertical furnace type combustion processing apparatus. In this apparatus, an auxiliary burner 53 is provided at a lower end side of a furnace body 51 in a flame sending space 52 for sending a flame into the furnace body 51 from a lateral direction. An exhaust gas inlet 54 for introducing exhaust gas to be burned from obliquely above is provided in the flame inlet space 52 so as to join the flame inlet space 52.

[0005] The furnace body 51 is provided with the auxiliary burner 53.
Air nozzles 55 are provided at a higher position, that is, a downstream position, at a plurality of locations distributed in the vertical direction and the circumferential direction, from which air for combustion is supplied into the furnace. Further, in the furnace main body 51, another auxiliary burner 56 is provided at a position above the air nozzle 55 in a lateral direction to promote combustion in the furnace.

In the apparatus shown in FIG. 2, the flue gas containing combustible substances introduced from the flue gas inlet 54 is heated by the flame of the auxiliary burner 53 and burns, while the furnace body 51
Rises inside. The upward flow is mixed with air from an air nozzle 55 and heated by the flame from another auxiliary combustion burner 56 to continue the combustion and exhaust the gas through an exhaust port 57 at the downstream end.

[0007]

In the apparatus shown in FIG. 2, however, the auxiliary burners 53, 56 are arranged transversely, that is, at right angles to the upward flow of the combustion gas toward the exhaust port 57 at the downstream end. Due to the provision, the following problems occur.

The flame F 1 from the auxiliary burners 53, 56,
Since F2 is blown out from the horizontal direction (horizontal direction),
Aboard the rising combustion gas in the furnace, the flame immediately turns its direction upwards and rises in speed. Therefore, the flame tends to be unstable, and harmful components (CO, dioxins) may be increased in the exhaust gas at the exhaust port 57 of the furnace, and even a misfire may occur.

[0009] When the flame is misfired, the furnace pressure may fluctuate when re-igniting.

In a furnace, a horizontal portion is provided on a peripheral wall of a base portion of a flame emitted from a combustion burner directed in a lateral direction, and dust is easily deposited or deposited on the horizontal portion. Once dust accumulation or deposition begins,
This proceeds at an accelerated rate. Therefore, the peripheral wall must be cleaned frequently. Further, dust may not be easily discharged even when cleaning is performed.

When the auxiliary combustion burner is a liquid fuel-fired burner, the fuel oil may be blocked by the deposited dust that has been deposited or deposited due to the above, and may leak out of the furnace to cause trouble.

An object of the present invention is to improve a dust-containing exhaust gas combustion treatment apparatus in consideration of these points.

[0013]

According to the present invention, an object of the present invention is to provide a flue gas inlet for introducing flue gas to be burned into a combustion chamber in a furnace upstream of the furnace and a flue gas outlet downstream of the furnace. And an auxiliary burner provided in the middle part of the furnace, the auxiliary burner is provided at an installation angle toward the upstream side.

In the present invention, since the auxiliary burner is provided at an installation angle toward the upstream side, for example, in the case of a vertical furnace, the installation angle is directed downward, so that the flame is also blown downward at the base portion. However, there is a downstream flow in the furnace, that is, an upward flow in a vertical furnace, so that the flame is also deflected in a direction closer to the tip of the flame. Therefore, a stagnation region is created between the base portion and the tip portion of the flame. Due to the occurrence of the stagnation region, the flame is stably maintained and misfire is prevented. As a result,
Is eliminated.

According to the present invention, in the vertical furnace, the auxiliary burner has a downward angle in any case, and in the horizontal furnace, the auxiliary burner can be directed downward by selecting an installation place. Dust near the periphery of the portion drops or flows down by its own weight, and does not accumulate or weld.

In the present invention, the installation angle of the auxiliary burner is preferably 20 ° to 60 ° with respect to a plane perpendicular to the axis of the furnace in relation to the flow of combustion gas in the furnace. Preferably it is about 30 °.

In order to more reliably maintain and promote in-furnace combustion, it is desirable that the furnace has an air nozzle, and that the auxiliary burner is provided at a downstream position with respect to the air nozzle. At that time, if the combustion chamber is divided into two areas that communicate with each other, the upstream primary combustion chamber and the downstream secondary combustion chamber, the auxiliary combustion burner is a primary combustion chamber for the primary combustion chamber. The secondary combustion burner for the secondary combustion chamber, and the air nozzle is composed of a primary air nozzle and a secondary air nozzle, the primary combustion burner is located downstream of the primary air nozzle and the secondary combustion burner is composed of two. Preferably, it is arranged downstream of the next air nozzle.

It is preferable that the distance between the primary air nozzle and the primary combustion burner and the distance between the secondary air nozzle and the secondary combustion burner be at least half the inner diameter of the furnace at the corresponding position.

In the present invention, the furnace has a temperature detecting device provided on the inner wall portion of the furnace near the position where the auxiliary burner is provided, and a control device for controlling energy input to the auxiliary burner,
Preferably, the control means is set so that the temperature at the furnace inner wall portion is set to be equal to or lower than the welding temperature of dust in the exhaust gas. In this way, while controlling the welding of dust to the furnace inner wall, In addition, the furnace temperature can be raised as high as possible.

[0020] In the auxiliary burner, the turning diameter of the flame of the auxiliary burner in the furnace is preferably not more than half of the inner diameter of the furnace at the corresponding position. This makes it easy to keep the temperature at the inner wall of the furnace at or below the dust deposition temperature even when the furnace center is at a high temperature.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, the furnace main body 1 of the dust-containing exhaust gas combustion treatment apparatus is made of a heat-resistant material and forms a vertical furnace. The furnace body 1 has a combustion chamber 2 in which an internal space burns exhaust gas, a dust discharge port 3 for dropping and discharging burned dust at a lower end, and an exhaust port 4 for exhaust at an upper end. Have been.

The combustion chamber 2 is an upstream primary combustion chamber 2
A is divided so that A is located at the lower part and the secondary combustion chamber 2B at the downstream side is located at the upper part. The inner diameter of a portion 2C that forms the lower end of the secondary combustion chamber 2B is smaller than that of the other portion.

An exhaust gas inlet 5 for supplying exhaust gas to be burned into the primary combustion chamber 2A and a pilot burner 6 are attached to a lower portion of the furnace main body 1. The exhaust gas inlet 5 is provided to be inclined downward toward the lower end of the furnace body 1. The exhaust gas inlet 5 has a partially premixed air 7.
Is supplied to the exhaust gas 8. or,
The pilot burner 6 is provided at the bottom of a concave portion 6A that is sunk below the inner wall surface of the furnace body 1, so that the flame of the pilot burner 6 is always in the concave portion 6A.

In the primary combustion chamber 2A of the furnace body 1, a primary combustion burner 9 is provided above the pilot burner 6, and a primary air nozzle 10 is provided between the primary combustion burner 9 and the pilot burner 6. Is provided. The auxiliary burner 9 is installed toward the upstream side, that is, obliquely downward in the case of the vertical furnace shown in FIG.

A secondary air nozzle 11 is provided at a lower end 2C of the secondary combustion chamber 2B. Further, a secondary combustion supporting nozzle 12 is provided at an upper position thereof.
The secondary combustion burner 12 is, like the primary combustion burner 9,
It is installed facing upstream, that is, obliquely downward.

The primary combustion burner 9 and the secondary combustion burner 1
2 has inclination angles of θ1 and θ2 with respect to the horizontal plane, respectively, and at the same time, the burner flame has the primary combustion chamber 2A,
In order to generate a swirl flow in each of the secondary combustion chambers 2B, a flame is injected toward a position eccentric with respect to the axis of the furnace main body 1. At this time, swirl flow diameters d1, d
2 is desirably not more than half of the furnace inner diameters D1 and D2, respectively.

The inclination angle θ1 of the primary auxiliary burner 9 and the inclination angle of the secondary auxiliary burner 10 are both 20 ° to 60 °, preferably about 30 °. The distance between the primary combustion burner 9 and the primary air nozzle 10 is at least half the furnace inner diameter D1 in the primary combustion chamber 2A, and the distance between the secondary combustion burner 12 and the secondary air nozzle 11 is the furnace in the secondary combustion chamber 2B. It is preferably at least half of the inner diameter D2.

In such an embodiment, the exhaust gas is combusted in the following manner.

First, the exhaust gas 8 containing combustible substances generated in the incinerator is introduced into the primary combustion chamber 2A from the exhaust gas inlet 5 in a state of being mixed with the partial premixing air 7.
At this time, the dust falls and is discharged from the dust discharge port 3, and the premixed gas rises and swirls with the air from the primary air nozzle 10. However, since the partial premixed gas has a mixture ratio outside the flammable limit, it does not ignite upstream of the primary air nozzle.

A flame is always emitted from the pilot burner 6 in the recess 6A, and ignites the exhaust gas to maintain the combustion. This exhaust gas promotes its combustion by heating from the primary combustion burner 9. The combustion gas rises on the upward swirling flow in which the flame of the primary combustion burner 9 is generated, and reaches the secondary combustion chamber 2A.

In the secondary combustion chamber 2B, the combustion gas is supplied with air from the secondary air nozzle 11 at a portion 2C, and is heated from the secondary combustion burner 12 when ascending to further promote combustion.

Then, the burned gas is exhausted from the exhaust port 4 to the outside of the furnace for processing.

In the combustion treatment of the exhaust gas, the primary auxiliary burner 9 and the secondary auxiliary burner 12 emit a flame downward, that is, upstream of the rising combustion gas. This flame changes its direction and rises upward, but forms a stagnation region at the lowest turning portion of the flame. That is, since the residence time of the combustible gas or oxygen as a reactant becomes long, the flame is stabilized and no misfire occurs. In addition, the turning diameter of the flame is less than half of the inner diameter of the furnace, that is, the high-temperature portion of the burner flame or the combustion gas is swirling only at the center of the furnace and does not reach the inner wall of the furnace. The situation of welding to the wall is avoided. Then, this dust is supplied to the primary combustion burner 9 and the secondary combustion burner 1
Since 2 is installed inclined downward, it falls by its own weight in the vicinity of the burner and hardly adheres to the inner wall surface of the furnace.

As a preferred embodiment of the present invention, a temperature detecting device for detecting the temperature of the inner wall of the furnace near the auxiliary burner and a control device for controlling the energy input to the auxiliary burner are provided. Is preferably equal to or lower than the dust welding temperature. By doing so, even if dust approaches the inner wall surface of the furnace, welding to the inner wall surface can be prevented.

The present invention is applicable even if it is not the vertical furnace shown in FIG. Even when the furnace is a horizontal furnace, the auxiliary burner is installed inclined so as to face the upstream side. When the flame is injected from the auxiliary burner with the combustion gas flowing from the upstream side to the downstream side inclined in such a manner toward the upstream side, a stagnation region is generated when the flame is deflected toward the downstream side. Due to the presence of the stagnation region, the flame is stabilized as described above. In addition, prevention of dust from adhering to the inner wall of the furnace due to falling can be easily achieved by arranging an auxiliary burner at an upper position of the horizontal furnace.

[0036]

As described above, in the present invention, since the auxiliary burner is installed inclined toward the upstream side, combustion in the furnace is stabilized without causing a stagnation region in the flame and causing misfire. As a result, long-term stability of in-furnace combustion is ensured, and low pollution of CO, dioxins and the like can be achieved. In addition, in the vicinity of the auxiliary burner, it is possible to eliminate the dust without adhering the dust and to control the trouble caused by the adhesion of the conventional dust and the welding, thereby securing the long-term stability of the combustion in the furnace and improving the operation rate. improves.

If the auxiliary burner and the air nozzle on the upstream side are combined, the combustible components in the exhaust gas and the air can be burned after being mixed, so that NOx and soot can be reduced,
The turndown can be extended to save energy.

Furthermore, if a control device is provided so that the inner wall surface of the furnace is kept at a temperature equal to or lower than the dust welding temperature, it is possible to prevent the welding of dust and the burnout of the furnace material and the burner device.

Further, if the turning diameter of the flame of the auxiliary burner is controlled, the temperature in the center of the furnace can be increased to reduce CO and dioxins, and furthermore, the inner wall of the furnace can be controlled. High temperature can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic configuration of an apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace (furnace main body) 2 Combustion chamber 2A Primary combustion chamber 2B Secondary combustion chamber 4 Exhaust port 5 Exhaust gas inlet 9 Combustion burner (primary combustion burner) 10 Air nozzle (primary air nozzle) 11 Air nozzle (secondary air nozzle) 12 burner burner (secondary burner burner) θ1 Installation angle θ2 Installation angle D1 Furnace inner diameter D2 Furnace inner diameter d1 Turning diameter d2 Turning diameter

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3K061 AB01 AC19 BA05 CA01 DA18 DB16 3K078 AA05 BA03 CA02 CA12 CA18 CA24

Claims (8)

[Claims] 1. An apparatus having an exhaust gas inlet for introducing exhaust gas to be burned into a combustion chamber in a furnace at an upstream side of the furnace and an exhaust port at a downstream side, and having an auxiliary burner in an intermediate portion of the furnace. , Wherein the auxiliary burner is provided at an installation angle toward the upstream side. 2. The dust-containing exhaust gas combustion treatment device according to claim 1, wherein the installation angle is 20 ° to 60 ° with respect to a plane perpendicular to the axis of the furnace. 3. The dust-containing exhaust gas combustion treatment apparatus according to claim 2, wherein the installation angle is about 30 ° with respect to a plane perpendicular to the axis of the furnace. 4. The dust-containing exhaust gas combustion treatment apparatus according to claim 1, wherein the furnace has an air nozzle, and the auxiliary burner is provided at a downstream position with respect to the air nozzle. 5. The combustion chamber is divided into two areas communicating with each other, a primary combustion chamber on the upstream side and a secondary combustion chamber on the downstream side, and the auxiliary combustion burner includes a primary combustion auxiliary burner for the primary combustion chamber and a secondary combustion chamber. A secondary combustion burner for the chamber, and the air nozzle comprises a primary air nozzle and a secondary air nozzle, the primary combustion burner being located downstream of the primary air nozzle and the secondary combustion burner being a secondary air nozzle. The dust-containing exhaust gas combustion treatment apparatus according to claim 4, wherein the apparatus is disposed at a downstream position of the exhaust gas. 6. The distance between the primary air nozzle and the primary combustion burner, and the distance between the secondary air nozzle and the secondary combustion burner are at least half of the inner diameter of the furnace at the corresponding position. The dust-containing exhaust gas combustion treatment device according to claim 5. 7. A furnace has a temperature detecting device provided on a furnace inner wall near a position where an auxiliary burner is provided, and a control device for controlling energy input to the auxiliary burner. The dust-containing exhaust gas combustion processing apparatus according to claim 1 or 5, wherein the temperature in the section is set to be equal to or lower than the welding temperature of dust in the exhaust gas. 8. The combustion burner according to claim 1, wherein the turning diameter of the flame of the combustion burner in the furnace is not more than half the inner diameter of the furnace at the corresponding position. The dust-containing exhaust gas combustion treatment apparatus according to any one of claims 6 and 7.