JPH062823A - Crematory - Google Patents

Abstract

PURPOSE:To permit the promotion of reduction of NOx as well as the retention of durability of a furnace wall without elongating a cremating time. CONSTITUTION:In a cremator equipped with a main combustion chamber 1 and a re-combustion chamber 2, sprayers 9, spraying ammonia solution against the inside of the re-combustion chamber 2 by spraying medium through an air pressure, is provided near the outlet port communicated with the flue of the re-combustion chamber 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a main combustion chamber and a recombustion chamber, and nitrogen oxides (NOx) generated during cremation.
The present invention relates to a cremation furnace having a denitrification function for reducing the above.

[0002]

As is well known, the combustion technology of cremation furnaces has improved and the exhaust gas has been made smokeless and odorless. However, the bodies and burial items contained a large amount of organic nitrogen and were cremated. At this time, since organic nitrogen burns to generate a large amount of nitrogen oxides, which causes pollution problems, reduction of NOx is required. In order to deal with this, conventionally, various measures have been taken, such as avoiding the inflow of excess air, lowering the flame temperature by water injection, and increasing the residence time of exhaust gas in the furnace.

Further, as a flue gas denitration technology, a non-catalytic decomposition method using ammonia is disclosed in Japanese Patent Publication No. 50-23664, which is a method in which an ammonia source is added to exhaust gas in a high-temperature atmosphere to produce nitrogen gas. It is reported that the oxide is converted into water and nitrogen, and the technique is applied to a refuse incinerator, in which case an aqueous ammonia solution is compressed and injected by the pressure.

[0004]

Although the conventional means can be reduced to some extent by the structure of the burner and the furnace itself, in the cremation furnace, it is desired that the cremation be performed in a short time, and the NOx reduction function is required. The conventional burner having the above-mentioned structure cannot meet the requirement, and particularly, in the early stage of cremation, a lot of organic nitrogen is generated, and there is a limit to the reduction.

Further, the above-mentioned publication discloses a denitration technology using ammonia, and describes a technology in which a heat-resistant obstacle is arranged in a distribution channel in order to enhance the contact effect between ammonia and nitrogen oxides. No applicable requirements are listed. That is, as described above, the cremation furnace produces a large amount of organic nitrogen, and does not suggest that it should be processed in a short time. Further, in the technology adopted for the refuse incinerator, the point of spraying is known, but even if water is compressed and sprayed, the size of the sprayed particles is generally 500 to 1000 μm.
When this is adopted in a cremation furnace, there is a problem that water drops are attached to the inner wall of the furnace and the denitration effect is lowered, and also a large defect that accelerates deterioration of the furnace wall occurs.

The present invention has been developed to solve the above problems, and does not extend the cremation time, and
Another object of the present invention is to provide a cremation furnace in which the reduction of Ox can be further promoted and the durability of the furnace wall is maintained.

[0007]

In a cremation furnace having a main combustion chamber and a re-combustion chamber, the solution according to the present invention is directed to the interior of the re-combustion chamber in the vicinity of the outlet portion leading to the flue of the re-combustion chamber. The gist of the present invention is to provide a sprayer for spraying the aqueous ammonia solution with a spray medium by air pressure. Furthermore,
It is preferable that the atomizer is provided so as to inject in a direction orthogonal to the flow direction of the exhaust gas. Further, the atomizer may be provided so as to inject in a direction opposite to the flow direction of the exhaust gas.

[0008]

[Function] Since the atomizer sprays the aqueous ammonia solution using the air pressure as the injection medium, the particle shape becomes extremely fine, the mixing of the mist-like ammonia water droplets and the exhaust gas is significantly promoted, and a large amount of NOx is rapidly discharged. The leakage of the aqueous ammonia solution can be prevented. Further, by injecting the sprayer from a direction orthogonal to or opposite to the flow direction of the exhaust gas, the injection force stirs the exhaust gas, further promoting the mixing of the ammonia water droplets and the exhaust gas.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS To explain the present invention in detail, FIGS. 1 and 2 show a co-current type cremation furnace having a main combustion chamber 1 below.
Exhaust gas generated in the main combustion chamber 1 is provided with a re-combustion chamber 2 on the upper side, a front door for loading and unloading the truck 3 in the main combustion chamber 1 is opened and closed by a fire door 4, and a main burner 5 is provided on the rear wall. Are guided from the front side to the rear side of the re-combustion chamber 2 through the communication passage 6. The re-combustion chamber 2 has a sub-burner 7 on its rear wall, and a flue 8 is connected to the outlet on the front side. The structure of the cremation furnace is the same as the conventional one, but in the reburning chamber 2, sprayers 9, 9 are provided on both side walls of the outlet part thereof so as to vertically oppose each other so as to face each other. The sprayers 9 and 9 are provided with an air pressure inlet 10 and an aqueous ammonia solution inlet 11.

The cremation furnace shown in FIGS. 3 and 4 is also called a countercurrent type, and similarly has a main combustion chamber 1 and a recombustion chamber 2, and the exhaust gas generated in the main combustion chamber 1 is discharged into the main combustion chamber 1. It is guided to the rear side of the re-combustion chamber 2 from the communication passage 6 provided at the rear side of the re-combustion chamber 2, which has the same structure as that of the conventional furnace. , 9 are provided.

It should be noted that the sprayer 9, 9 is best mounted at the outlet of the recombustion chamber 2, but it is not necessarily limited to this position. Also has a denitration effect. However, when it is provided near the sub burner 7 of the re-combustion chamber 2, the sprayed ammonia burns, and reduction of NOx cannot be expected. Further, the staggered state of the sprayers 9, 9 is not limited to the above-mentioned top and bottom, but may be set to the staggered front and back.

Next, in the examples shown in FIGS. 5 and 6, a single atomizer 9 is provided on the side wall of the recombustion chamber 2, and its injection direction is biased above or below the center of the recombustion chamber 2. It was installed so that it would be positioned. However, it is not always necessary to deviate, and the effect of stirring the exhaust gas can be obtained even if it is provided so as to inject toward the center of the re-combustion chamber 2.

In the example shown in FIG. 7, the re-combustion chamber 2 is provided with the atomizer 9 on the front wall of the re-combustion chamber 2, that is, the wall facing the auxiliary burner 7.
It is provided so as to inject toward the inside. Further, in the example shown in FIG. 8, the atomizer 9 is provided so as to be capable of injecting from the exhaust port of the re-combustion chamber 2 toward the inside of the chamber. In these examples, injection is performed so as to oppose to the flow direction of the exhaust gas. is there.

FIG. 9 shows a flow chart for injecting an aqueous ammonia solution into the reburn chamber 2. In the figure, reference numeral 12 is an aqueous ammonia solution tank, 13 is a flow meter, 14 is a solenoid valve, and 15 is a valve. Is a pressure gauge, 16 is an air-compressor, 17
Is a pressure reducing valve, and 18 is a regulating cock. A high pressure (0.5
kg to 10 kg) or low pressure (0.04 kg to 0.2)
(kg). In the case of low pressure, a turbo blower or a roots blower is used. By injecting with high pressure or low pressure air pressure, it is possible to easily make the water droplets of the aqueous ammonia solution as small as 50 μ to 70 μ, and as a result of the experiment, if the average particle shape is 100 μ or less, the purpose can be achieved Was found.

By spraying the aqueous ammonia solution with the sprayer 9, the gas burned in the re-combustion chamber 2 is spirally stirred in the direction orthogonal to the flow direction, and at the same time, the aqueous ammonia solution is mixed in the gas. Small water drops are mixed in to reduce nitrogen oxides. Further, in the case of jetting so as to face the exhaust gas, the jetted water droplets are U-turned and the mixing time with the exhaust gas is sufficiently maintained.

By the way, by experiment, the set position of the sprayer was divided into three parts, that is, near the auxiliary burner, the central part and the outlet part, and the denitrification rate was measured. However, the concentration of NH ₃ is 1%,
Comparison will be made under the condition that the injection amount of NH ₃ is 10 l / H. (1) Approximately 28% of the sub-burner side (2) Central part of approximately 36% (3) Outlet part of approximately 40% As a result, when the sprayer is installed at the outlet of the reburning chamber and the aqueous ammonia solution is injected Was the most efficient. Further, the denitrification rate increases as the injection amount of the aqueous ammonia solution increases, but on the other hand, the amount of ammonia that leaks as it is tends to increase. When the amount of leak ammonia increases, the odor concentration also increases, which also causes pollution. Therefore, the injection amount of ammonia is NH _{3 in} molar ratio; NO = 0.3
The range of 75-2; 1 was found to be most suitable.

Then, as a result of conducting an experiment under the above respective conditions by setting a pair of atomizers 9 and 9 in the conventional cremation furnace, FIG.
The chart table shown in FIG. In the figure, the solid line A is the measured value before the injection of the aqueous ammonia solution (point a in FIG. 1), the dotted line B is the measured value after the injection (point b in FIG. 1), and the chain line C is O ₂ In the table, the Y axis of the table shows the passage of time (MINUTS) from ignition, and the X axis shows the NOx amount PPM and the temperature (TEMP). Looking at the results shown in FIG. 10, the maximum value at the measurement position a is about 230 PP.
Although M is shown, the value at point b after injection is about 140P.
It is known to exhibit PM and decrease by about 90 PPM.
Therefore, the effect was a reduction ratio of 140/230 × 100 = 60%, that is, about 40%. The dotted line B in FIG.
The injection of the aqueous ammonia solution was stopped at point d,
This was done in order to clarify the denitration effect during injection, that is, at the same time when the injection of the aqueous ammonia solution was stopped, N
It can be seen that Ox increases all at once. In the above experiment, a pair of atomizers are provided so as to face each other in a staggered manner, but when one atomizer is stopped and the other one is operated, it is about 40 to 50% though not shown. The decrease in efficiency was clarified. Further, as seen from the solid line A in FIG. 10, the NOx emission pattern has peaks in the early stage of combustion and the middle stage of combustion, and this pattern exhibits a substantially constant phenomenon although there is an inherent difference in combustion. . Therefore, it is not necessary to continuously inject ammonia from the beginning of cremation to the end, and the injection may be stopped after the peak has passed.

[0017]

In the cremation furnace according to the present invention, a sprayer having an air pressure as an injection medium is provided in the vicinity of the outlet of the reburning chamber, and the aqueous ammonia solution is injected from the atomizer. However, it is not a simple injection, and the air pressure is the injection medium. Since it is injected by a sprayer, the shape of the injected water droplets is extremely fine, the contact rate with the exhaust gas is extremely good, and the reduction of a large amount of nitrogen oxides contained in the exhaust gas is treated in a short time. It is possible. Moreover, since the sprayed water droplets have an extremely fine particle shape, they are rapidly vaporized, so that the water droplets do not adhere to the wall of the furnace and the durability of the furnace can be maintained. Further, if the atomizer is provided in a direction orthogonal or opposite to the flow direction of the exhaust gas, the exhaust gas is agitated by the injection force of the atomizer, and the extremely fine water droplets and the exhaust gas of the aqueous ammonia solution are atomized. The mixing ratio is extremely good. As a result, the contact time with the exhaust gas is maintained for a long time, and a large amount of organic nitrogen is denitrated in a short time to a value that is further reduced than the legally regulated amount.

[Brief description of drawings]

FIG. 1 is a side sectional view of a cremation furnace according to the present invention.

FIG. 2 is a sectional view of the same as seen from the front.

FIG. 3 is a side sectional view of a cremation furnace according to another example of the present invention.

FIG. 4 is a sectional view similarly seen from the front.

FIG. 5 is a cross-sectional view showing an example in which one atomizer is provided in the reburning chamber.

FIG. 6 is a sectional view showing another example in which one atomizer is provided in the reburning chamber.

FIG. 7 is a side sectional view showing an example in which a sprayer is provided at another position.

FIG. 8 is a side sectional view showing an example in which a sprayer is provided at another position.

FIG. 9 is a piping diagram showing injection of an aqueous ammonia solution.

FIG. 10 is a chart showing the generation state of NOx obtained by an experiment.

[Explanation of symbols]

 1 Main Combustion Chamber 2 Re-combustion Chamber 5 Main Burner 7 Sub Burner 9 Atomizer 10 Air Pressure Inlet 11 Ammonia Aqueous Solution Inlet

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tetsuji Fukushima 4-8-30-111 Maruyamadai, Konan-ku, Yokohama-shi, Kanagawa (72) Inventor Mitsugu Noguchi 255 Santanda-cho, Asahi-ku, Yokohama-shi, Kanagawa (72) Inventor Hirano Shozo 2-6-16 Rinkan, Yamato City, Kanagawa Prefecture Minami Rinkan Heights 107 (72) Inventor Kaido Aizawa 1-2-22-6-301 Namiki, Kanazawa-ku, Yokohama-shi, Kanagawa (72) Inventor, Satoshi Suzuki Konan, Yokohama-shi, Kanagawa 2-19-33, Higashi-Kamiokaoka (72) Inventor group Yuichi Yuichi, 628 Noba-machi, Konan-ku, Yokohama-shi, Kanagawa Prefecture B12-503 (72) Kazuyoshi Obama 1-1, Iwama-cho, Hodogaya-ku, Yokohama-shi, Kanagawa 5 (72) Inventor Kazuo Watanabe 1-19-17 Nagatahigashi, Minami-ku, Yokohama-shi, Kanagawa

Claims (3)

[Claims] 1. A cremation furnace having a main combustion chamber (1) and a recombustion chamber (2), wherein an aqueous ammonia solution is directed toward the interior of the recombustion chamber in the vicinity of an outlet portion leading to a flue of the recombustion chamber (2). Atomizer (9) for injecting air with an air injection medium
A cremation furnace characterized by being equipped with. 2. The cremation furnace according to claim 1, wherein the atomizer (9) is provided so as to inject in a direction orthogonal to the flow direction of the exhaust gas. 3. The cremation furnace according to claim 1, wherein the atomizer (9) is provided so as to inject in a direction opposite to the flow direction of the exhaust gas.