JP3383959B2 - Waste incinerator combustion method and apparatus - 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 of burning waste in an incinerator for reburning residual unburned gas in exhaust gas from the incinerator.

[0002]

2. Description of the Related Art Generally, combustible waste discharged from homes is collected and incinerated in a refuse incinerator for disposal.
Such an incinerator has a dry stoker that dries the dust supplied by the dust supply device, a combustion stoker that burns the dust from the dry stoker, and a post-combustion stoker that burns the dust from the burning stoker and burns it. is doing.

The dry stoker, the combustion stoker, and the post-combustion stoker are provided in the lower part of the furnace body, the exhaust gas cooling chamber is formed in the upper part of the furnace body, and the exhaust port for discharging the exhaust gas is formed in the upper end of the furnace body. .

Recently, in the refuse incinerator, the exhaust gas generated by burning the refuse by the primary air in the stoker of the refuse incinerator is guided to the secondary combustion path of the furnace body and is secondary by the secondary air. The tendency to be burned is increasing.

Under these circumstances, dioxin has been regarded as a problem in recent years. That is, for the production of dioquins in an incinerator for municipal solid waste, (1) Dioxins contained in the components of the municipal solid waste have passed through the incinerator without undergoing thermal decomposition or oxidative decomposition. , (2) those generated by the gas-phase reaction after the exit of the incinerator and the gas-solid reaction involving the fly ash surface, and (3) those generated at around 300 ° C. in the exhaust gas cooling process.

Due to the problems of dioxins and the like, it has been required to achieve complete combustion of refuse. A higher level of complete combustion control has been demanded from the conventional furnace temperature control, which only requires the furnace temperature to be within a certain range. The achievement of complete combustion is evaluated by the CO concentration in the exhaust gas, the remaining amount of carbon in the exhaust gas, and the like.

While the purification of exhaust gas is demanded in this way, the dust in the combustion zone on the combustion stoker of the furnace body is burned in the state of complete combustion or close to it and becomes an oxidizing high temperature combustion gas. In the dry bed on the stoker, since the dust that has not dried sufficiently is burned, incomplete combustion occurs and unburned gas is likely to be generated.

In order to achieve complete combustion of waste, more stable combustion on the primary combustion side (dust supply amount, primary air amount control) and unburned gas in the high-temperature exhaust gas left behind in the primary combustion In the combustion path, it is required to mix with secondary air to promote secondary combustion. An example of this type of waste combustor, which uses vortex flow in a secondary combustion path to mix with secondary air, is disclosed in Japanese Utility Model Laid-Open No. 4-108131.

However, according to the conventional method of burning waste in a refuse incinerator, the exhaust gas guided to the secondary combustion path of the furnace body is secondarily burned by the secondary air. Even if the unburned gas in the exhaust gas is mixed with the secondary air blown out from the furnace body in the secondary combustion path, the mixing is insufficient and it is possible to secure a wide range of high temperature range. Have difficulty.

Therefore, there is a problem that the secondary combustion of the residual unburned gas in the exhaust gas generated in the primary combustion is still incomplete. As a result, there is a problem in that the CO concentration is insufficiently reduced, and dioxin is still generated frequently.

Therefore, in order to completely burn the exhaust gas by the secondary combustion, it is important to secure the three factors of the temperature of the exhaust gas, the stagnant time, and the mixing. From this point of view, for example, A refuse incinerator shown in Japanese Patent Application No. 4-303858 has been proposed.

In the refuse incinerator described in Japanese Patent Application No. 4-303858 mentioned above, the exhaust gas introduced into the secondary combustion passage of the furnace body is provided with upper jet nozzles formed on the opposite wall surfaces of the secondary combustion passage. It is intended to secure the temperature, stagnant time, and mixing of the exhaust gas, which are the above three factors, by performing secondary combustion by the upper-stage blowout flow and the lower-stage blowout flow respectively supplied from the upper and lower jet nozzle groups.

[0013]

However, in the refuse incinerator described in Japanese Patent Application No. 4-303858 mentioned above, the cooling area in the secondary combustion passage is still large and the generation of eddy currents is small, so that the exhaust gas is exhausted. Was insufficiently mixed, and it was difficult to achieve secondary combustion of residual unburned gas in the exhaust gas. Therefore, there is a problem that the secondary combustion of the residual unburned gas in the exhaust gas generated in the primary combustion is still incomplete. As a result, there is a problem in that the CO concentration is insufficiently reduced, and dioxin is still generated frequently.

The present invention has been made to solve the above-mentioned problems, and its purpose is to narrow the cooling zone in the secondary combustion passage and increase the generation of vortex flow from the secondary air. According to the present invention, there is provided a waste combustion method for a waste incinerator that reduces the residual rate of unburned gas and burns the waste more completely.

[0015]

The invention according to claim 1 is
The primary air is supplied to the stoker of the refuse incinerator to burn the waste primary, and the exhaust gas guided to the secondary combustion path of the furnace body is discharged into the upper and lower jet nozzles formed on the opposite wall surfaces of the secondary combustion path. In the waste combustion method of a waste incinerator in which secondary combustion is performed by the upper and lower blow streams respectively supplied from the group, the horizontal cross section of the secondary combustion path of the furnace body is configured in a rectangular shape, and From a pair of injection holes formed on one of the opposite wall surfaces of the secondary combustion path at a predetermined distance, a pair of lower-stage blowout flows are blown out so that their streamlines are directed to the vicinity of the center of the other wall surface. With
From the pair of nozzles formed on the other wall surface of the upper jet nozzle group at a predetermined distance, the upper jet stream having a streamline that is substantially parallel to the direction outside the streamlines of the pair of lower jet streams, respectively. It is characterized by blowing out.

According to the second aspect of the present invention, the primary air is supplied to the stoker of the refuse incinerator to perform the primary combustion of the refuse, and the exhaust gas guided to the secondary combustion path of the furnace body is opposed to the secondary combustion path. In a refuse incinerator refuse combustor's waste combustion device that performs secondary combustion by the upper and lower blowout streams respectively supplied from the upper and lower jets formed on the wall surface, the horizontal cross section of the secondary combustion path of the furnace body is rectangular. The lower-stage injection port group is formed on one of the opposing wall faces of the secondary combustion path, and the streamlines of the lower-stage blowout flows are directed to the vicinity of the center of the other wall face. Together with a pair of nozzles located at a predetermined distance from each other, the upper-stage nozzle group is formed on the other wall surface of the opposing wall surfaces of the secondary combustion path,
The upper-stage jet nozzles are a pair of jet nozzles located at positions separated by a predetermined distance while blowing out upper-stage jets each having a streamline outside the streamlines of the respective lower-stage jets and being substantially parallel to the direction of the streamlines. It is characterized by being formed.

[0017]

According to the first aspect of the invention, the primary air is supplied to the stoker of the refuse incinerator to perform the primary combustion of the waste, and the exhaust gas guided to the secondary combustion path of the furnace body is opposed to the secondary combustion path. In the waste combustion method of a refuse incinerator, in which the secondary combustion flow is performed by the upper-stage and lower-stage blowout flows respectively supplied from the upper-stage jet port group and the lower-stage jet port group formed on the wall surface, A pair of lower-stage blowout flows from the pair of lower-stage jet ports formed in a pair of lower-stage jet ports separated from each other by a predetermined distance on one of the facing wall faces of the secondary combustion passage From the pair of nozzles formed on the other wall surface of the upper jet nozzle group at a predetermined distance from each other toward the outside of the streamline of the pair of lower jet flows. A streamline that is almost parallel to To blown upper blowout flow to each.

According to the second aspect of the present invention, the lower-stage blowout flow has a streamline of the other from the pair of nozzles of the lower-stage jet port group of one of the facing wall faces of the secondary combustion passage of the furnace body. By blowing out toward the vicinity of the center of the wall surface, vortexes are branched and generated on both sides of the lower stage blowout flow, and the vortex flow generation area occupies the entire plane area of the furnace body.

Further, since a pair of jets of the upper jet port group of the other wall surface blows out an upper jet having a streamline which is substantially parallel to the direction outside the streamline of the lower jet, the upper jet is discharged. On both sides of the blowout flow, vortices are branched and generated, and the regions where the vortices are generated occupy the entire plane region of the furnace body.

Then, for example, the unburned gas from the dry zone side of the furnace body and the oxidative high temperature combustion gas from the combustion zone rise, but the unburned gas is supplied by the supply of the lower blow stream and the upper blow stream. The oxidative high temperature combustion gas mixes with them, and a vortex between them and the above-mentioned lower-stage blowout flow and upper-stage blowout flow is three-dimensionally formed.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 show a refuse incinerator of a refuse incinerator according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 indicates a refuse incinerator. This waste incinerator 1 includes a hopper 2 to which waste is supplied by a waste crane (not shown), and this hopper 2.
From a hopper chute 3 that guides trash, a dust extruder having a trash chute 3 that transfers trash from the hopper chute 3, a drying stoker 5 that dries the dust supplied by the dust hopper, and a drying stoker 5 It is provided with a combustion stoker 6 that burns the waste and a post-combustion stoker 7 that burns the waste from the combustion stoker 6 and burns it.

The above-mentioned waste extruder 4 comprises a hopper chute 3
It is provided at the bottom of. The dry stoker 5, the combustion stoker 6, and the post-combustion stoker 7 are housed in a furnace body 8, an exhaust port 9 for discharging combustion gas is formed at an upper end of the furnace body 8, and a side wall surface of the furnace body 8 is formed. A cooling water supply port 10 and a secondary air blower 11 are provided, and an auxiliary combustion burner 12 is provided at the lower end of the furnace body 8.

Inside the furnace body 8, the primary combustion chamber 1 above the drying stoker 5, the combustion stoker 6, and the post-combustion stoker 7 is installed.
3 and the secondary combustion passage 14 near the blower 11 for the secondary air,
It is composed of a gas cooling passage 15 above the secondary combustion passage 14. The blower 11 for secondary air is the primary combustion chamber 13 of the furnace body 8.
It is provided directly above.

As shown in FIG. 3, the horizontal cross section of the furnace body 8 in the vicinity of the secondary combustion passage 14 is formed in a rectangular shape, and combustion of the opposite wall surfaces 16 and 17 of the secondary combustion passage 14 is performed. On the wall surface 16 on the belt side, a lower jet nozzle group X including a pair of jet nozzles 18 and 19 is formed at a predetermined distance. Further, in FIG. 1, the lower jet nozzle group X and the blower 11 for secondary air are connected via a secondary air supply pipe 11A. From the nozzles 18 and 19 of the lower nozzle group X, the lower outlet flows F01 and F02 are blown out so that their streamlines are directed to the midpoint P of the wall surface 17 on the dry zone side in the horizontal plane.

In FIG. 1 and FIG. 2, the upper jet group Y composed of a pair of jet nozzles 20 and 21 and the blower 1 for the secondary air.
1 is connected via the secondary air supply pipe 11B.
The upper jet group Y is located at a position vertically higher than the lower jet group X of the wall surface 16 on the combustion zone side by about 1 m, and the lower jet flow F01, F from the pair of jet nozzles 20, 21 of the upper jet group Y.
Upper stage blowout flows F03 and F04 having a streamline outside the streamline of 02 and parallel to the direction thereof are blown out in the horizontal plane.

The reason why the number of nozzles forming the lower jetting group X and the upper jetting group Y is set to 4 will be described below.
Generally, the amount of primary combustion air is calculated from the lower heating value (kcal / Kg) and the planned amount of treatment (Kg / h) of the incinerated waste as a calculation method when the secondary air is not considered as the amount of combustion air. The theoretical air amount (A ₀₁ ) necessary for the above is given by an air amount obtained by adding an excess air ratio of 1.7.

In this embodiment, secondary air is provided for secondary combustion, and the amount of secondary air (A ₂ ) is about 1 / 1.5 times the amount of primary air (A ₁ ). Is preferable for complete combustion, and therefore the total air amount of primary air and secondary air should be the combustion air amount for combustion.

Therefore, if the total excess air ratio is λ ', it is given by A ₀₁ × λ' = A ₁ + A ₂ , and if the minimum excess air ratio of primary air is calculated as 1.4, then = A ₀₁ × 1.4 + A ₀₁ × 1.4 × 2/3 = A ₀₁ × 2.33, and the excess air ratio λ ′ = 2.33. That is, the excess air ratio λ ′ of the total air amount (including the secondary air) with respect to the theoretical air amount (A ₀₁ ) is about 2.3.

The secondary air amount is 0. 0 of the theoretical air amount (A ₀₁ ).
It requires about 9 times. A ₂ = A ₀₁ × 0.9 ····· (1) On the other hand, the theoretical air amount (A ₀₁ ) (unit: Nm ³ / h) is Ros.
From the formula of in, A ₀₁ = {(1.01 × H _e /1000)+0.5}×R (2)

Here, H _e : lower heating value (true heating value)
(Kcal / Kg) R: Planning throughput (Kg / h) for example, and H _e = 2000kcal / Kg, as a range that can be processed in per furnace, planned throughput = 1500 Kg
/ H to 4000 Kg / h, and substituting into equation (2), A ₀₁ = {(1.01 × 2000/1000) +0.5} × (1500 to 40000) = 3780 to 10080 (Nm ³ / h ) (3) Next, assuming that the secondary air blowing temperature is room temperature and is 20 ° C., from the formula (1), theoretical air at 0 ° C. (273 ° K) is 20 ° C. When the temperature is converted into the actual air amount, A ₂ = (3780 to 10080) × (273 + 20) /273×0.9=3651 to 9737 m ³ / h.

Then, the secondary air blowing speed is set to 20 m / s.
Assuming ec, the required cross-sectional area of the injection port is S = (3651 to 29737) /3600×1/20=0.0507 to 0.1352 m ² .

[0033] about the width of the furnace body 8 corresponding to the above values 0.0507M ² is 1200 mm, the above values 0.1352M ²
The width of the furnace body 8 corresponding to is about 3000 mm. Therefore, the diameter of the injection port of the secondary combustion air blown toward the furnace body is
125 A when the furnace width is 1200 mm (A means the nominal diameter of the pipe), 200 A when the furnace width is 3000 mm (A
Means the nominal diameter of the pipe).

Therefore, the appropriate number of nozzles is n ₁ = 0.0507 m ² /{(π×(0.1308) ² × 1/4} = 3.78 Therefore, it is appropriate that the number of nozzles is 4 To be done.

In the case of 125 A, the outer diameter of the nozzle =
Assuming that the thickness is 139.8 mm and the wall thickness is 4.5 mm, the inner diameter of the nozzle is 139.8-9 = 130.8 mmΦ. On the other hand, n ₂ = 0.1352 m ² /{(π×(0.2047) ² × 1/4} = 4.11 Therefore, it is appropriate that the number of injection ports is four.

In the case of 200 A, the outer diameter of the injection port =
If the diameter is 216.3 mm and the wall thickness is 5.8 mm, the inner diameter of the nozzle is 216.3-11.6 = 204.7 mmΦ.

Next, the injection holes 18, 19, 20, 21 described above
The procedure for determining the position and the blowing angle will be described with reference to FIG. From the pair of nozzles 18 and 19 of the lower nozzle group X, the lower outlet flows F01 and F02 are respectively on the other wall surface 17 in the horizontal plane.
Are blown out toward the point P, and the streamlines meet at the point P, which is the midpoint of the wall surface 17 of the dry zone.

In FIG. 4, a triangle N ₁ PN ₂ and a trapezoid N
₁ PK ₁ K _2, the position of the N _1, N ₂ are determined as trapezoidal N ₂ PK ₃ K ₄ is approximately the same area, the triangle N ₁ PN
The area of ₂ is S ₀ = S ₁ + S ₂ . The directions of the nozzles 18 and 19 are the same as the direction of the streamline N ₁ P and the direction of the streamline N ₂ P.

Next, N ₃ and N are set so that S ₁ = S _2.
The position of No. ₄ is determined, and the directions of the nozzles 20 and 21 of the upper stage nozzle group Y are the same as the directions of the nozzles 18 and 19 of the lower stage nozzle group X. As a result, the mixing due to the planar vortex flow efficiently occurs.

In this embodiment, however, high temperature primary air is blown into the lower part of the dry stoker 5, the lower part of the combustion stoker 6 and the lower part of the post-combustion stoker 7, respectively. The waste is transferred forward while being stirred and unraveled in the dry stoker 5, conveyed from the dry stoker 5 to the combustion stoker 6, and further stirred and stirred in the combustion stoker 6.
While being unraveled, it is primarily burned, transferred to the front and carried to the post-combustion stoker 7.

The waste on the dry stoker 5, the combustion stoker 6, and the post-combustion stoker 7 is stably burned by the waste supply amount, the primary air amount control, etc., and the exhaust gas is generated. The exhaust gas rises in the furnace body 8, It passes through the secondary combustion passage 14.
Unburned exhaust gas rises from the dry zone on the dry stoker 5, and oxidative high temperature combustion gas rises from the combustion zone on the combustion stoker 6.

On the other hand, an amount of secondary air corresponding to the primary air is blown into the secondary combustion chamber 14 from the secondary air blower 11 at an appropriate blowing speed, and the secondary combustion chamber 14 is blown.
Inside, mixing with residual unburned gas in the exhaust gas is promoted.
Here, the amount of secondary air is about 1 of the amount of primary air.
/1.5. As for the secondary air, the secondary combustion effect is sufficiently brought about even at room temperature, but the secondary combustion is made more effective by blowing in the high temperature air after the heat exchange with the exhaust gas as the secondary air. be able to.

Then, from the pair of nozzles 18 and 19 of the lower jet nozzle group X of the wall 16 on the combustion zone side of the secondary combustion passage 14, the lower-stage blowout flows F01 and F02 are respectively located in the horizontal plane at the midpoint of the wall 17 on the dry zone side. It is blowing toward P. The vortexes M01 and M02 are branched and generated on both sides of the lower-stage outlet flow F01, and the vortex M2 is generated on both sides of the lower-stage outlet flow F02.
03 and M04 are branched and generated. Therefore, the area in which the vortex flows M01, M02, M03, M04 are generated occupies the entire plane area of the secondary combustion passage 14 of the furnace body 8.

At the same time, from the pair of nozzles 20 and 21 of the upper jet group Y of the wall 17 on the dry zone side of the secondary combustion passage 14 to the vertical direction from the nozzles 18 and 19 of the lower jet group X of the wall 16 on the combustion zone side. Since the upper-stage blowout flows F03 and F04 are blown out in the horizontal plane at a position elevated by a predetermined distance, the upper-stage blowout flow F
The vortexes M05 and M06 are branched and generated on both sides of the streamline of 03, respectively, and the vortexes M07 and M08 are branched and generated on both sides of the streamline of the upper stage blowing flow F04. Therefore, the region where the vortex flows M05, M06, M07, and M08 are generated occupies the entire plane region of the secondary combustion passage 14 of the furnace body 8.

Then, the unburned gas from the dry zone and the oxidizing high temperature combustion gas from the combustion zone rise, but the unburned gas is supplied by the supply of the lower-stage blowout flows F01 and F02 and the upper-stage blowout flows F03 and F04. When the gas and the oxidizing high temperature combustion gas are mixed, the lower stage blowout flow F01, F02, the upper stage blowout flow F03,
A vortex consisting of F04, unburned gas, and oxidizing high temperature combustion gas is three-dimensionally formed.

In order to confirm the effect of introducing the secondary air by the nozzle having the above-mentioned constitution, the test was conducted on 10 cases in which the position of the nozzle was provided in the furnace body as follows. FIG. 7 shows the first case, FIG. 8 shows the second case, FIG. 9 shows the third case, FIG. 10 shows the fourth case, and FIG. 11 shows the fifth case.
The sixth case is shown in FIG. 12, the seventh case is shown in FIG.
FIG. 14 shows the eighth case in FIGS. 15 and 16, the ninth case is shown in FIGS. 17 and 18, and the tenth case of this embodiment is shown in FIGS.

The tests from the first case to the sixth case were conducted in the refuse incinerator shown in FIG. 6 at the injection port positions shown in FIGS. 7 to 12. FIG. 7 shows the first case. In the drawing, the horizontal cross section of the secondary combustion passage 14 of the furnace body 8 is formed in a rectangular shape, and the injection port 22 is formed at the midpoint of the wall surface 17 on the dry zone side of the wall surfaces 16 and 17 facing each other. The direction is perpendicular to the wall surface 17. According to this configuration,
The blowout flow F1 is blown out from the injection port 22 and swirls M1 and N1 are formed.

In the first case, the number of nozzles 22 is one and the amount of air per nozzle is large, so that the cooling area is concentrated in one place and uniform mixing cannot be achieved. In addition, the number of eddies generated is small.

FIG. 8 shows the second case. In the figure,
The horizontal cross section of the secondary combustion passage 14 of the furnace body 8 is formed in a rectangular shape, and the wall surface 1 on the combustion zone side of the wall surfaces 16 and 17 facing each other.
A nozzle 23 is formed at the end of the nozzle 6, and the direction of the nozzle 23 is perpendicular to the wall surface 16. Nozzle 2 on the wall 17 on the dry zone side
An injection port 24 is formed at the end opposite to 3, and the direction of the injection port 24 is perpendicular to the wall surface 17. According to this configuration, the blowout flow F2 is blown out from the injection port 23, and at the same time, the blowout flow F3 is blown out from the injection port 24, so that the vortex flows M2 and N2 are formed.

In the second case, the number of injection holes 22 is two, but the experimental results are the same as in the first case.
FIG. 9 shows the third case. In the figure, the horizontal cross section of the secondary combustion passage 14 of the furnace body 8 is formed in a rectangular shape, and the injection port 25 is formed at the midpoint of the wall surface 16 on the combustion zone side of the wall surfaces 16 and 17 facing each other. The direction is perpendicular to the wall surface 16. The nozzles 26 and 27 are formed on the wall surface 17 on the dry zone side, and the directions of the nozzles 26 and 27 are perpendicular to the wall surface 17. According to this configuration, the blowout flow F4 from the injection port 25
Is blown out, and at the same time, the blowout flow F5 from the nozzles 25 and 26
Since the blowout flow F6 blows out, the vortex flows M3, M3, N3, N
3 is formed.

In the third case, the injection ports 25, 26, 27
The number of is three, but the generation of eddy currents is small.
FIG. 10 shows the fourth case. In the drawing, the horizontal cross section of the secondary combustion passage 14 of the furnace body 8 is formed in a rectangular shape, and the injection ports 28, 29 that are close to the center of the wall surface 16 on the combustion zone side of the wall surfaces 16, 17 facing each other are formed. The directions of the injection holes 28 and 29 are perpendicular to the wall surface 16. Wall 1 on the dry zone side
7, nozzles 30 and 31 are formed apart from each other.
The directions of 0 and 31 are perpendicular to the wall surface 17. Spout 2
8, 29 and the nozzles 30, 31 are at the same height.

According to this structure, the blowout flows F5 and F6 are blown out from the injection ports 28 and 29, and at the same time, the injection ports 30 and 31 are released.
The blowout flow F7 and the blowout flow F8 are blown out from the vortex M
4, M4, N4 and N4 are formed.

In the fourth case, although there is an advantage that the generation of vortices can be increased, the blown flows of the injection ports 28 and 29 and the injection ports 30 and 31 interfere with each other, and the vortices become smaller. In addition, each blown flow does not meander in the horizontal cross-sectional direction, and the stagnant time of exhaust gas is shortened.

FIG. 11 shows the fifth case. In the figure, the horizontal cross section of the secondary combustion passage 14 of the furnace body 8 is formed in a rectangular shape, and the four wall surfaces 16, 16A, 17, 17A are provided with nozzles 32, 33, 34, 35, respectively.
2, 33, 34, and 35 have four wall surfaces 16, 17,
It is perpendicular to 16A and 17A. Each spout 3
2, 33, 34 and 35 have the same height.

According to this structure, the injection ports 32, 33, 3
The blowout flows F9, F10, F11, F12 are blown out from 4, 35 to form a vortex flow M5. The fifth case has an advantage that the unburned gas and the high-temperature gas are uniformly mixed, but the stagnant time of the exhaust gas is shortened due to the increase in the flow velocity of the exhaust gas.

FIG. 12 shows the sixth case. In the drawing, the horizontal cross section of the secondary combustion passage 14 of the furnace body 8 is formed in a rectangular shape, and the injection holes 35, 36, 37, 38 are formed on the wall surface 16 of the opposing wall surfaces 16, 17 on the combustion zone side, The directions of the nozzles 35, 36, 37, 38 are perpendicular to the wall surface 16. Nozzles 39, 40, 41, on the wall 17 on the dry zone side
42, 43 are formed, and the nozzles 39, 40, 41, 42,
The direction of 43 is perpendicular to the wall surface 17.

According to this structure, the injection ports 35, 36, 3
The blowout flows F13, F14, F15, F16 are blown out from 7, 38, and at the same time, the injection ports 39, 40, 41, 42, 43.
Outflow from F17, F18, F19A, F19, F20
Blows out.

In the sixth case, the blowout flow is blown out from the nine nozzles, so that the cooling region becomes large and the mixing effect is small. Moreover, no eddy current is generated. The wall of the blown air is formed, the width of the secondary combustion path becomes narrow, and the exhaust gas short-passes.

For the tests from the seventh case to the tenth case, the refuse incinerator shown in FIG. 1 was used.
Test the 7th case at the position of the nozzle shown in 4,
The eighth case is tested at the position of the nozzle shown in FIGS. 15 and 16, and the ninth case is tested at the position of the nozzle shown in FIGS.
The case No. 10 was tested, and the tenth case of this example was tested at the position of the nozzle shown in FIGS.

13 and 14 show the seventh case. In the figure, the furnace body 8 has a rectangular cross-section, and the nozzle 4 is formed on the wall surface 17 on the dry zone side of the wall surfaces 16 and 17 facing each other.
4, 45, 46, 47, 48 are formed and the injection holes 44, 4 are formed.
The directions of 5, 46, 47 and 48 are perpendicular to the wall surface 17. Nozzles 50, 51, 52, 5 on the wall 16 on the combustion zone side
3 is formed, and the directions of the injection ports 50, 51, 52, 53 are perpendicular to the wall surface 16. Nozzles 44, 45, 46, 4
7, 48 are located a predetermined distance above the positions of the injection ports 50, 51, 52, 53.

According to this structure, the injection ports 44, 45, 4
Outflows F21, F22, F23, F from 6, 47, 48
24 and F25 blow off, and at the same time, injection holes 50, 51, and 5
The blowout flows F26, F27, F28, and F29 blow out from 2, 53.

In the seventh case, in addition to the same effect as in the sixth case, since the number of injection ports is large, the air volume per injection port is small, and the change in the exhaust gas flow path is hardly seen. 15 and 16 show the eighth case. In the figure, the horizontal cross section of the secondary combustion passage 14 of the furnace body 8 is formed in a rectangular shape, and the nozzles 54, 55 are formed on the wall surface 17 of the opposing wall surfaces 16, 17 on the dry zone side. Is perpendicular to the wall surface 17. Wall 1 on the combustion zone side
Nozzles 56 and 57 are formed in the nozzle 6, and the directions of the nozzles 56 and 57 are perpendicular to the wall surface 16. The nozzles 54 and 55 are located a predetermined distance above the positions of the nozzles 56 and 57.

According to this structure, the blowout flows F30 and F31 are blown out from the injection holes 54 and 55, and the swirl flows M6 and N6 are generated. At the same time, blowout flows F32, F3 from the nozzles 56, 57
3 is blown out, and vortexes M7 and N7 are generated.

In the eighth case, eddies are often generated. Further, since the positions of the nozzles 54, 55 and the nozzles 56, 57 are vertically different, the exhaust gas meanders and the residence time can be lengthened. On the other hand, since the distance between the injection ports 56, 57 of the wall surface 16 on the combustion side is narrow, a relatively large cooling area is generated.

17 and 18 show the ninth case. In the drawing, the horizontal cross section of the secondary combustion passage 14 of the furnace body 8 is formed in a rectangular shape, and the nozzles 54, 55 are formed on the wall surface 17 on the dry zone side of the wall surfaces 16, 17 facing each other.
The direction of 55 is perpendicular to the wall surface 17. Injection ports 56 and 57 are formed on the wall surface 16 on the combustion zone side, and the injection ports 56 and 57 are formed.
Is perpendicular to the wall surface 16. Nozzles 54, 55
Is located a predetermined distance above the positions of the injection ports 56, 57.

According to this structure, the blowout flows F30 and F31 are blown out from the injection holes 54 and 55, and the swirl flows M8 and N8 are generated. At the same time, blowout flows F32, F3 from the nozzles 56, 57
3 is blown out, and the vortexes M9, M10, N9, and N10 are branched and generated.

In the ninth case, more eddy currents are generated than in the eighth case. In addition, the nozzles 54, 55 and the nozzles 56,
Since the position of 57 has a vertical drop, the exhaust gas meanders and the residence time can be lengthened. On the other hand, the relatively large cooling area is created by increasing the distance between the injection ports 56 and 57 of the wall 16 on the combustion side. However, in the vicinity of the outlet of the secondary combustion passage 14, the cooling areas on the combustion side and the dust supply side overlapped.

The tenth case of this embodiment is shown in FIG.
As described above with reference to FIG. 3, eddy currents are generated more frequently than in the ninth case. Also, the spouts 18, 19
Since there is a vertical drop between the nozzles 20 and 21 and
The stagnant time of the exhaust gas can be increased. Further, the upper outlet flows F03, F0 of the outlets 20, 21 of the upper outlet group Y
Since 4 is inclined, vortex flows M05, M06, M
07 and M08 are branched and generated. Vortex M0
The area where 5, M06, M07, and M08 occur occupies the entire plane area of the secondary combustion passage 14 of the furnace body 8.

Further, since the lower-stage blowout flows F01, F02 of the lower-stage nozzles X are jetted 18, 19 are inclined,
Vortices M01, M02, M03, and M04 are branched and generated. The region where the vortexes M01, M02, M03, M04 are generated occupies the entire plane region of the secondary combustion passage 14 of the furnace body 8. Therefore, it is dispersed outside the cooling zone.

Then, as a typical example of the above first to tenth cases, a sixth case and a fourth case are given.
The case and the eighth case were selected, and the tenth case of the present example was tested under the following experimental conditions. The experimental conditions were as follows: the exhaust gas entering the secondary combustion passage 14 from the primary combustion chamber 13 had a rising gas temperature from the dry zone of 750 ° C., an exhaust gas flow velocity of 1.7 m / sec, and an rising exhaust gas temperature from the combustion zone side of 950. C. and the exhaust gas flow rate was 2.6 m / sec. It should be noted that this is an average of the measurement data obtained when the secondary combustion air is not blown in divided into two on the dry zone side and the combustion zone side.

The temperature of the secondary air is 20.degree.
As an evaluation criterion for the experimental results, (A) an air flow vector that mixes the unburned gas from the dry zone and the oxidizing high temperature combustion gas from the combustion zone is preferable.

(B) For planar mixing at the blowing position, an air flow vector that produces a vortex is preferable. (C) It is better that the temperature distribution at the outlet of the secondary combustion passage 14 is more uniform.

(D) It is preferable that the concentration of CO is low. First, the experimental results of the sixth case are shown in FIGS.
Shown in 1. About evaluation standard (A), both wall surfaces 16,
Due to the blowing from 17, the exhaust gas passes through the central portion of the furnace body 8 at a high speed. Regarding the evaluation standard (B), the number of nozzles is large and no planar mixing is observed. As for the evaluation criteria (C), since the combustion reaction is not taken into consideration, the cooling zone that crosses the central part (around 750 ° C)
Is getting bigger. CO concentration of evaluation standard (D) is 22
It is 6 ppm. The numbers in the frame showing the secondary combustion path 14 in FIG. 21 indicate the temperature (unit: ° C.).

The experimental results of the fourth case are shown in FIGS.
3, shown in FIG. Regarding the evaluation criterion (A), the crossing state of the unburned gas and the oxidizing high temperature combustion gas in the blow-in portion is seen as compared with Case 6. Regarding the evaluation criterion (B), a planar vortex flow is generated, and planar mixing is good. Regarding the evaluation criterion (C), the cooling area in the central portion of both wall surfaces 16 and 17 is divided into two and is smaller than that in the sixth case. The CO concentration of the evaluation standard (D) is 100 ppm. The numbers in the frame showing the secondary combustion path 14 in FIG. 24 indicate the temperature (unit: ° C.).

The experimental results of the eighth case are shown in FIGS.
6, shown in FIGS. 27 and 28. Regarding the evaluation standard (A), a flow occurs in which the unburned gas and the oxidizing high temperature gas intersect. Regarding the evaluation criterion (B), a vortex is generated at each blowing position. Regarding the evaluation criterion (C), the cooling region is further smaller than that in the fourth case, and the temperature distribution spreads to a higher temperature. The CO concentration of the evaluation standard (D) is 35 ppm. The numbers in the frame showing the secondary combustion path 14 in FIG. 28 are temperature (unit:
(° C) is shown.

The experimental results of the tenth case are shown in FIGS.
0, FIG. 31, and FIG. Regarding the evaluation standard (A), a flow occurs in which the unburned gas and the oxidizing high temperature gas intersect. Regarding the evaluation criterion (B), a vortex is generated at each blowing position. Regarding the evaluation criterion (C), the cooling region is smaller than that in the eighth case, and the temperature distribution spreads to a higher temperature. The CO concentration of the evaluation standard (D) is 35 ppm or less. The numeral in the frame showing the secondary combustion passage 14 in FIG. 32 indicates the temperature (unit: ° C.).

According to the above configuration, the secondary combustion passage 14
Since the lower-stage blowout flows F01 and F02 and the upper-stage blowout flows F03 and F04 which are vertically separated from the wall surfaces 16 and 17 facing each other, blow off time of the exhaust gas in the secondary combustion passage 14 can be secured.

Further, since the lower-stage blowout flows F01 and F02 are obliquely blown out from the wall surface 16 on the combustion zone side, and at the same time, the upper-stage blowout flows F03 and F04 are obliquely blown from the wall surface 17 on the dry zone side, so that the lower-stage blowout flow F01 is obtained. , F02 and the upper-stage airflows F03, F04 are branched and generated,
Therefore, many eddies are generated, for example, the unburned gas from the dry zone and the oxidizing high temperature combustion gas from the combustion zone can be more mixed, and the range of the cooling region can be narrowed.

In this way, the cooling range of the exhaust gas can be narrowed, the stagnant time can be secured, and the mixing can be increased, so that the secondary combustion of the residual unburned gas in the exhaust gas generated in the primary combustion is promoted. Therefore, it is possible to reduce the residual rate of unburned gas in the exhaust gas and burn the dust more completely.
As a result, the CO concentration is reduced and the generation of dioxins can be reduced.

In this embodiment, the lower jet nozzle group X
From the pair of nozzles 18 and 19 of
1, F02, and those streamlines have the other wall surface 17 in the horizontal plane.
Although it is designed to blow out toward the midpoint P of the lower wall, the lower-stage blowout flows F01 and F02 are blown out so that their streamlines are near the center near the midpoint P of the other wall surface 17 in the horizontal plane. You can also do so.

Further, in the present embodiment, as shown in FIG. 4, in plan view, the streamlines of the upper-stage discharge flows F03 and F04 are parallel to the streamlines of the lower-stage discharge flows F01 and F02 in the horizontal plane. However, they may be substantially parallel.

Further, in this embodiment, the pair of nozzles 20 and 21 of the upper jet nozzle group Y on the wall 17 on the dry zone side are perpendicular to the nozzles 18 and 19 of the lower jet group X on the wall 16 on the fuel zone side. Although the position is about 1 m higher in the direction, it goes without saying that it is not limited to such a numerical value.

In the present embodiment, the stream lines of the lower-stage blowout flows F01 and F02 and the upper-stage blowout flows F03 and F04 are in a horizontal plane (at right angles to the wall surface 16 on the combustion zone side and the wall surface 17 on the dry zone side). ), Each of the lower and upper airflows is drawn along their streamlines.
It is also possible to blow out at a slanted angle with respect to the horizontal plane, and four modification examples of the refuse incinerator according to the embodiment of the present invention are shown in FIGS. 33, 34, 35 and 36.
Is shown in.

FIG. 33 shows a first modified example. The direction of the streamline of the lower-stage blowout flow F41 from the wall surface 16 on the combustion zone side is inclined downward by a predetermined angle from the horizontal plane, while the wall surface 17 on the dry zone side is formed. The direction of the streamline of the upper-stage outlet flow F42 from is inclined upward by a predetermined angle from the horizontal plane.

FIG. 34 shows a second modification, in which the streamline of the lower-stage blowout flow F43 from the wall surface 16 on the combustion zone side is inclined downward by a predetermined angle from the horizontal plane, while the wall surface 17 on the dry zone side is formed. The direction of the streamline of the upper-stage blowout flow F44 from is inclined downward by a predetermined angle from the horizontal plane.

FIG. 35 shows a third modified example. The direction of the streamline of the lower-stage blowout flow F45 from the wall surface 16 on the combustion zone side is inclined upward by a predetermined angle from the horizontal plane, while the wall surface 17 on the dry zone side is formed. The direction of the streamline of the upper stage outlet flow F46 from is inclined upward by a predetermined angle from the horizontal plane.

FIG. 36 shows a fourth modification in which the direction of the streamline of the lower-stage blowout flow F47 from the wall surface 16 on the combustion zone side is inclined upwards by a predetermined angle from the horizontal plane, while the wall surface 17 on the dry zone side is provided. The direction of the streamline of the upper-stage blowout flow F48 from is inclined downward by a predetermined angle from the horizontal plane.

[0088]

As described above, according to the present invention,
Since the lower-stage and upper-stage airflows which are vertically separated from the opposite wall surfaces of the secondary combustion path are blown out at an angle, vortexes are generated by branching from the lower-stage airflow and the upper-stage airflow, respectively. Is generated, for example, the unburned gas from the dry zone and the oxidizing high temperature combustion gas from the combustion zone can be mixed more and the range of the cooling zone can be narrowed.

As a result, the cooling range of the exhaust gas is narrowed, the stagnant time is secured, the mixing is increased, and the secondary combustion of the residual unburned gas in the exhaust gas produced in the primary combustion is promoted. It is possible to reduce the residual rate of unburned gas in the exhaust gas and burn the dust more completely. As a result, C
It has the effect of reducing the O concentration and reducing the generation of dioxins.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a refuse incinerator according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the secondary combustion path taken along line X2 of FIG.

3 is a cross-sectional view of the secondary combustion path taken along line X3 in FIG.

FIG. 4 is an explanatory diagram for determining a position of a nozzle and a blowing angle on a wall surface of a furnace body.

FIG. 5 is an explanatory diagram of an operation state of the present embodiment.

FIG. 6 is a configuration diagram of a refuse incinerator according to another experimental condition of the present embodiment.

FIG. 7 is a cross-sectional view of a secondary combustion path showing a flow of secondary air according to the first case.

FIG. 8 is a sectional view of a secondary combustion passage showing a flow of secondary air according to a second case.

FIG. 9 is a sectional view of a secondary combustion passage showing a flow of secondary air according to a third case.

FIG. 10 is a sectional view of a secondary combustion passage showing a flow of secondary air according to a fourth case.

FIG. 11 is a sectional view of a secondary combustion path showing a flow of secondary air according to a fifth case.

FIG. 12 is a sectional view of a secondary combustion passage showing a flow of secondary air according to a sixth case.

FIG. 13 is a sectional view of a secondary combustion passage showing a flow of secondary air according to a seventh case.

FIG. 14 is a sectional view of a secondary combustion path showing a flow of secondary air according to a seventh case.

FIG. 15 is a sectional view of a secondary combustion path showing a flow of secondary air according to an eighth case.

FIG. 16 is a sectional view of a secondary combustion path showing a flow of secondary air according to an eighth case.

FIG. 17 is a sectional view of a secondary combustion passage showing a flow of secondary air according to a ninth case.

FIG. 18 is a sectional view of a secondary combustion passage showing a flow of secondary air according to a ninth case.

FIG. 19 is a distribution diagram showing an airflow vector in the vertical direction showing the experimental result of the sixth case.

FIG. 20 is a distribution diagram showing an air flow vector in the horizontal direction showing the experimental result of the sixth case.

FIG. 21 is an exhaust gas temperature distribution chart showing the experimental results of the sixth case.

FIG. 22 is a distribution diagram showing an air flow vector in the vertical direction showing the experimental result of the fourth case.

FIG. 23 is a distribution diagram showing an airflow vector in the horizontal direction showing the experimental result of the fourth case.

FIG. 24 is an exhaust gas temperature distribution chart showing the experimental results of the fourth case.

FIG. 25 is a distribution diagram showing an air flow vector in the vertical direction showing the experimental result of the eighth case.

FIG. 26 is a distribution diagram showing an air flow vector in the horizontal direction showing the experimental result of the eighth case.

FIG. 27 is a distribution diagram showing an air flow vector in the horizontal direction showing the experimental result of the eighth case.

FIG. 28 is an exhaust gas temperature distribution diagram showing the experimental results of the eighth case.

FIG. 29 is a distribution diagram showing an airflow vector in the vertical direction showing the experimental result of the tenth case.

FIG. 30 is a distribution diagram showing an air flow vector in the horizontal direction showing the experimental result of the tenth case.

FIG. 31 is a distribution diagram showing an air flow vector in the horizontal direction showing the experimental result of the tenth case.

FIG. 32 is an exhaust gas temperature distribution chart showing the experimental results of the tenth case.

FIG. 33 is a configuration diagram showing a first modification of the refuse incinerator according to the embodiment of the present invention.

FIG. 34 is a configuration diagram showing a second modification of the refuse incinerator according to the embodiment of the present invention.

FIG. 35 is a configuration diagram showing a third modification of the refuse incinerator according to the embodiment of the present invention.

FIG. 36 is a configuration diagram showing a fourth modification of the refuse incinerator according to the embodiment of the present invention.

[Explanation of symbols]

1 garbage combustion furnace 8 furnace body 11 Secondary air blower 14 Secondary combustion path 16 Combustion zone side wall 17 Walls on the dry zone side 18 nozzles 19 nozzles 20 spouts 21 nozzle X Lower stage nozzle group Y Upper stage nozzle group F01 lower stream F02 lower stream F03 Upper stream F04 Upper stream

Continuation of the front page (56) Reference JP-A-5-196218 (JP, A) JP-A-49-83262 (JP, A) JP-A-5-26421 (JP, A) JP-A-3-225106 (JP , A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) F23G 5/14 ZAB F23G 5/00 109 F23G 5/44 ZAB

Claims (2)

(57) [Claims] 1. A primary stage of supplying waste air to a stoker of a refuse incinerator for primary combustion of the refuse and introducing exhaust gas introduced into a secondary combustion path of the furnace body to an upper stage formed on opposite wall surfaces of the secondary combustion path. In the waste combustion method of a waste incinerator in which secondary combustion is performed by the upper and lower jet flows supplied from the nozzle group and the lower nozzle group, respectively, the horizontal cross section of the secondary combustion path of the furnace body is configured in a rectangular shape, From a pair of nozzles formed at a predetermined distance on one of the wall surfaces of the secondary combustion path facing each other in the group of nozzles, a pair of lower-stage blowout flows have their streamlines directed toward the center of the other wall surface. Streamlines that are substantially parallel to the direction outside the streamlines of the pair of lower-stage blowout streams from a pair of nozzles formed on the other wall surface of the upper-stage jet orifice group at a predetermined distance. It has an upper effluent flow with Waste combustion process of the incinerator, characterized in that to blown out. 2. The upper stage formed on the opposite wall surfaces of the secondary combustion path for the exhaust gas introduced into the secondary combustion path of the furnace body by supplying primary air to the stoker of the refuse incinerator to perform primary combustion of the waste. In a refuse incinerator refuse combustor in which secondary combustion is performed by the upper-stage and lower-stage blowout flows supplied from the nozzle group and the lower-stage nozzle group, respectively, the horizontal cross section of the secondary combustion path of the furnace body is configured to have a rectangular shape. The lower jet port group is formed on one of the opposing wall faces of the secondary combustion passage, and the lower jet port group is formed such that the streamlines of the lower jet flows respectively toward the center of the other wall face and are separated by a predetermined distance. A pair of nozzles at different positions, and the upper-stage nozzle group is formed on the other wall surface of the opposing wall surface of the secondary combustion path, and the upper-stage nozzle group is formed outside the streamline of each lower-stage outlet flow. Has a streamline that is almost parallel to the direction of the streamline Stage blowout flow dust combustion apparatus incinerator, characterized in that formed in the pair of nozzle hole in a position spaced apart a predetermined distance together with the blowing respectively.