JP3040723B2 - Furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a furnace provided with an exhaust gas outlet, such as a melting furnace or a pyrolysis furnace for incinerated ash of municipal waste and industrial waste.

[0002]

2. Description of the Related Art There is an increasing need for ash melting furnaces for reducing the volume and harmlessness of ash generated after incineration of garbage.
NaCl and KCl are included in the exhaust gas from the furnace where the waste incineration ash is melted.
Gasified low-boiling substances such as are present in high concentrations, and those that existed in the furnace at high temperatures in gaseous form
When the temperature comes out of the furnace, the temperature drops, liquefies and solidifies, and the exhaust gas outlet is closed.

When exhaust gas is extracted from a slag port as in the furnace described in Japanese Patent Application Laid-Open No. 6-300234, a part of the ash falling into the molten pool is located because the exhaust gas outlet is located below the furnace. Is carried over, and the liquefied low-boiling substance is mixed and solidified, and solid deposits are formed in the outlet, and the outlet is closed.

[0004]

As described above, in a furnace such as an ash melting furnace or a pyrolysis furnace, N2 contained in a large amount of exhaust gas is used.
When low-boiling substances such as aCl and KCl are gasified, they are liquefied and condensed and solidified due to a decrease in temperature when they leave the furnace, which causes a problem in that the exhaust gas outlet is closed.

The present invention is intended to prevent a gasified low-boiling substance contained in exhaust gas from solidifying and solidifying in a furnace having an exhaust gas outlet, such as a furnace for melting incineration ash, to block the exhaust gas outlet. It is an object to provide a configured furnace.

[0006]

In order to solve the above-mentioned problems, the present invention has a structure in which a high-temperature gas or a combustion gas is blown into exhaust gas to keep the temperature of the exhaust gas high near the exhaust gas outlet. Is adopted.

As described above, in the conventional furnace, gaseous substances having a low boiling point, such as NaCl and KCl, which are contained in a large amount in the exhaust gas, are liquefied and condensed and solidified by lowering the temperature when they leave the furnace. The mouth was obstructed, which was a problem. This can be confirmed from the fact that when the temperature is lowered as shown in FIG. KCl has the same tendency.

On the other hand, in the furnace according to the present invention, as described above, a high-temperature gas or a combustion gas is blown into the vicinity of the exhaust gas discharge port and mixed with the high-temperature gas or by combustion of a combustible component by the blown combustion gas. The generated high-temperature gas can keep the exhaust gas at a high temperature similar to the inside of the furnace (even if the temperature is lower than that, the temperature is reduced), and can prevent the exhaust gas outlet from being blocked due to the solidification of NaCl, KCl and the like.

Further, since the high-pressure gas generated by the injection of the high-temperature gas or the combustion of the combustible gas can reduce the partial pressure of the low-boiling-point vapor as shown in FIG.
Low-boiling substances such as 1 and KCl can be present in the gas, and the clogging of the exhaust gas discharge port due to coagulation and solidification of NaCl and KCl can be prevented.

Further, by blowing the high-temperature gas, the exhaust gas which had flowed through a part of the flow path due to the dead space was stirred by the injection gas and flowed through the entire flow path. The partial pressure of the steam can be reduced (the effect of FIG. 6), and the blockage of the exhaust gas outlet due to the solidification of NaCl, KCl or the like can be prevented.

Further, if the flow velocity of the blown gas is increased and the flow velocity of the high-temperature gas near the exhaust gas outlet is increased,
It can blow off deposits near the blowing,
It is possible to prevent the exhaust gas outlet from being blocked due to the solidification of l, KCl and the like. This is particularly effective for blowing off carryover ash when exhaust gas is extracted from the slag port as in the furnace described in Japanese Patent Application Laid-Open No. 6-300234.

By injecting a high-temperature gas or a combustion gas into the vicinity of the slag outlet, the exhaust gas can be maintained at a high temperature comparable to the inside of the furnace (the temperature can be reduced even less), and by blowing the high-temperature gas, In the case of extracting exhaust gas from the slag outlet as in the furnace described in JP-A-6-300234, the heat release from the slag can be reduced and solidification of the slag can be prevented. be able to. Also, since the exhaust gas can be kept at a high temperature, NaC
Blockage of the slag port due to coagulation of l, KCl, etc. can be prevented.

The gas blowing means employed in the furnace of the present invention preferably has a structure in which the gas is introduced so as to form a curtain on the wall surface through which the exhaust gas is introduced.
When the gas blowing means configured as described above is adopted, a curtain is formed by gas on the wall surface of the attachment portion, and the partial pressure of the low-boiling-point vapor is reduced on the wall surface so that NaC
Blockage can be prevented by allowing l, KCl and the like to be present in the gas.

Further, the carryover ash and low-boiling-point dust in the exhaust gas are blown off at the gas flow rate of the curtain, so that the carryover ash and low-boiling-point dust can be prevented from adhering. Further, by forming a curtain, a decrease in temperature on the wall surface can be reduced, and adhesion of low-boiling substances can be prevented.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments in which the present invention is applied to a combustion ash melting furnace will be specifically described below with reference to the drawings.

(First Embodiment) First, an ash melting furnace according to a first embodiment shown in FIGS. 1 and 2 will be described. In this embodiment, FIG. 1 and FIG.
As shown in FIG. 1, a blind cap 3 is attached, and an air blowing pipe (20ASUS pipe) 1 having an elbow 4 and four air blowing ports 2 each having a diameter of 3 mm are opened downward. What was installed 20 cm above the bottom was used. Here, the air to in FIG. 1 is for a wall curtain.

In this test, high-temperature gas is generated by blowing air near the slag port and burning CO in exhaust gas. However, the high-temperature gas may be blown into the exhaust gas as a high-temperature gas such as N ₂ gas or a burner combustion gas heated by a heat exchanger. In FIG. 1, reference numeral 5 denotes a socket, and 6 denotes a casing.

In FIG. 1, air 7 is supplied from the right side of the figure by a compressor, and is supplied to an air blowing pipe (20A).
SUS pipe (1) is injected downward from a pipe outlet 2 through a SUS pipe (1). In FIG. 2, the molten slag 9 passes through a slag port 12 provided in the refractory 11 and is discharged through a slag gutter 8. The exhaust gas 10 is guided from the furnace interior 13 to the exhaust gas duct 14 via the slag port 12.

The installation position of the air blowing pipe 1 is
At 20 cm above the bottom surface of the slag gutter 8. For temperature measurement, 1 cm 10 cm downstream from the air outlet 2
The measurement was performed at two places: 18 thermocouples (1) provided 0 cm below and 19 thermocouples (2) provided downstream of the thermocouple.

The exhaust gas duct 14 contains a mixture of the exhaust gas 10 and the leaking air 15. Exhaust gas duct 14
After passing through the cooling air 16, the CO and CO ₂ concentrations are measured before the bag filter 17, and the gas enters the bag filter 17.

The amount of exhaust gas 10 is 20 Nm^Three/ h, CO
Concentration 30%, CO_TwoConcentration 20%, N _Two50% concentration
6 to 18 Nm, which is enough to completely burn CO gas^Three/ h
Air 7 was blown. At this time, the temperature of the blowing air 7
When the temperature is 200 ° C., the blown gas flow rate is 100-30.
High speed of 0m / s. In addition, blowing CO theoretical air volume
If it is trapped, the temperature of (exhaust gas 10 + air 7) is 400
It is calculated to increase by about ° C. Table 1 shows the test results.

[0022]

[Table 1]

In this test, since the air 7 was always supplied so as not to block the air outlet 2, no test result was obtained on the same day when the air 7 was stopped. From the experience so far, the temperature of the thermocouple (2) 19 when the air 7 was not blown was about 600 ° C.
At a temperature of about 100 ° C. by blowing 12 Nm ³ / h. It is considered that this is smaller than 400 ° C. in the previous calculation because there is cooling by the leaking air 15 from another.

Regarding the CO concentration, the amount of air 7 is 18 Nm ³
At / h, it is reduced to 270 ppm, and CO combustion can be confirmed. Further, when the air 7 is blown at 12 Nm ³ / h, the total gas amount becomes about 1.6 times, so that the partial pressure of the low boiling point vapor is reduced to about 60%.

Since the temperature rises and the partial pressure of the low-boiling vapor decreases, it is easy for low-boiling substances to be present in the gas. In addition, in this experiment, it is considered that the attached matter near the blowing was blown off because the blowing speed was as high as 200 m / s. Due to these effects, in the present experiment, the slag port that had been closed so far was not closed.

(Second Embodiment) Next, an ash melting furnace according to a second embodiment shown in FIG. 3 will be described. In FIG. 3, the exhaust gas 10 flows from the furnace interior 13 through the slag port 12 to the exhaust gas duct 14. In this embodiment, the gas 21 to be blown into the exhaust gas discharge port is passed through a wind box 21 ′ to form a porous body 20.
A curtain is formed on the wall surface that supplies the exhaust gas and guides the exhaust gas. Examples of the material of the porous body 20 include a ceramic and a sintered body.

As described above, in order to efficiently form a curtain on a wall surface serving as an attachment portion, it is preferable that two systems, that is, a lower system and a lateral system can be separately controlled. In addition, the same components as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description thereof will be omitted.

Third Embodiment Next, a description will be given of an ash melting furnace according to a third embodiment shown in FIG. In FIG. 4, the exhaust gas 10 flows from the furnace interior 13 through the slag port 12 to the exhaust gas duct 14. In the present embodiment, the gas 21 to be blown into the exhaust gas outlet is supplied from the downward nozzle 22 and the horizontal nozzle 23 to form a curtain on the wall surface.

In this embodiment, the gas from the downward nozzle 22 is arranged alternately in the flow direction so as not to collide with the gas from the horizontal nozzle 23. That is, the downward nozzle 22 forms a curtain on the side surface of the gutter and the downward nozzle 23
Forms a curtain on the upper surface.

In the configuration shown in FIG. 4, the nozzle is shown as having a circular hole. However, as shown in FIG. 5, the nozzle may have a slit in addition to the circular hole. In the case of slitting, if both the downward slit nozzle 24 and the horizontal slit nozzle 25 are long in the flow direction, a curtain can be easily formed. Also, as in the previous embodiment,
In order to efficiently form a curtain at the attachment portion, it is preferable that two systems, that is, a lower system and a lateral system can be separately controlled.

The slit nozzle is manufactured by flattening the tip of the pipe. In addition, the same components as those described in the above embodiment are denoted by the same reference numerals, and redundant description thereof will be omitted.

[0032]

As described above, the furnace according to the present invention is provided with gas blowing means for blowing high-temperature gas or combustion gas into exhaust gas to maintain the temperature of the exhaust gas at a high temperature near the exhaust gas outlet. The blowing of gas from the blowing means prevents the temperature of the exhaust gas from lowering, whereby gaseous low-boiling substances such as NaCl and KCl, which are contained in the exhaust gas in a large amount, are not coagulated and solidified, and the exhaust gas outlet is not blocked.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a slag port portion in an ash melting furnace according to a first embodiment of the present invention.

FIG. 2 is an explanatory view showing an arrangement of an air blowing pipe in a slag outlet shown in FIG. 1;

FIGS. 3A and 3B are diagrams showing a configuration of a slag port portion in an ash melting furnace according to a second embodiment of the present invention, wherein FIG.
(B) is a cross-sectional view.

FIG. 4 is a drawing showing a configuration of a slag port portion in an ash melting furnace according to a third embodiment of the present invention, where (a) is a longitudinal sectional view,
(B) is a cross-sectional view.

5 (a) is a longitudinal sectional view and FIG. 5 (b) is a transverse sectional view showing a modification of the ash melting furnace according to the third embodiment of the present invention shown in FIG.

FIG. 6 is a table showing the relationship between NaCl temperature and vapor pressure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air blow-in pipe 2 Air blow-out port 3 Blind cap 4 Elbow 5 Socket 6 Casing 7 Air 8 Slag gutter 9 Slag 10 Exhaust gas 11 Refractory 12 Slag port 13 Furnace 14 Exhaust gas duct 15 Leakage air 16 Cooling air 17 Bag filter Reference Signs List 18 thermocouple (1) 19 thermocouple (2) 20 porous body 21 blowing gas 21 'wind box 22 downward nozzle 23 horizontal nozzle 24 downward slit nozzle 25 horizontal slit nozzle

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshimasa Kawami 12 Nishikicho, Naka-ku, Yokohama-shi Mitsubishi Heavy Industries, Ltd. Inside Yokohama Works Co., Ltd. (72) Susumu Nishikawa 1-8-1, Koura, Kanazawa-ku, Yokohama-shi Mitsubishi Heavy Industries, Ltd. (56) References JP-A-9-72518 (JP, A) JP-A-8-54102 (JP, A) JP-A-6-265129 (JP, A) (58) Fields studied (Int .Cl. ⁷ , DB name) F23J 15/08

Claims (2)

(57) [Claims] 1. A furnace provided with an exhaust gas discharge port,
A furnace provided with gas blowing means for blowing a high-temperature gas or a combustion gas into the exhaust gas to maintain the temperature of the exhaust gas at a high temperature near the exhaust gas outlet; 2. The furnace according to claim 1, wherein the gas blowing means is configured to guide the gas so as to form a curtain on a wall surface through which the exhaust gas is guided.