JPH09236232A - Manufacture of superheated steam utilizing incineration heat of waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to efficiently reduce chlorine and to obtain superheated steam of high temperature by providing char mixture supply port supplied from pyrolysis means at the lower part of falling or rising flow area of circulating fluid area. SOLUTION: Fluid medium 2-1 such as fluid sand is contained on a dispersing plate 3 such as a porous plate in a pyrolysis furnace 1 having a fluidized bed, the sand and waste such as municipal refuse are introduced from a waste supply line 4 and sand circulation line 5, a fluidized bed space at 300 deg.C or higher is generated from combustion exhaust gas supplied from a combustion exhaust gas inlet line 6, and the pyrolysis reaction of the waste is conducted. The pyrolysis gas generated by the reaction is separately removed from a pyrolysis gas outlet line 7, char mixture having undecomposed residue and sand is removed from a char mixture removal line 9, and unburned matter is removed from an unburned matter removing line 8. Accordingly, the removal of the unburned matter and the separation of the medium are efficiently conducted, and stable pyrolysis and char combustion can be executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of superheated steam by incinerating municipal refuse or industrial waste, producing steam by the heat of the combustion exhaust gas, and using the steam in a power plant or the like. .

[0002]

2. Description of the Related Art Conventionally, fluidized bed incinerators are often used as incinerators for incinerating waste such as municipal solid waste, and such apparatuses are accommodated on a dispersion plate (for example, a perforated plate) in a fluidized bed incinerator. The fluidized medium is fluidized and heated by blowing air or incineration exhaust gas etc. from below the dispersion plate into the fluidized medium such as sand, and waste such as municipal solid waste is thrown into the fluidized bed thus formed. Burn. The combustion gas generated by the combustion reaches a boiler via a combustion gas outlet line, generates steam by thermal contact with hot water in the boiler, and uses the steam as a turbine drive source of a power plant or the like.

[0003]

The waste such as municipal waste contains chlorine-containing organic compounds such as vinyl chloride plastic, and the combustible content of Cl is about 0.2 to 0.
Contains 5%. Then, chlorine contained in PVC plastics mixed in waste such as municipal waste becomes HCl by combustion (usually, HC in exhaust gas from combustion of municipal waste is
(1 is about 500 to 1000 ppm), which acts on the tube of the steam generating boiler installed downstream of the incinerator to corrode it. In particular, when the tube surface temperature is about 350 ° C. or higher, high-temperature corrosion becomes remarkable as the temperature increases. For this reason, conventionally, the tube surface temperature had to be 350 ° C. or less, and the temperature of the produced steam was limited to about 300 ° C. As a result, the power generation efficiency of conventional waste incineration is about 15
% Or less and the fuel efficiency is about 30 to 40%, which is significantly lower than the plant power generation efficiency of about 30 to 40%, in which the boiler tube temperature can be set to 500 to 600 ° C. by using heavy oil or LNG, which contains almost no chlorine, as fuel. Was there.

In view of the above technical problems, the present inventors simultaneously applied for an invention relating to the production of superheated steam capable of efficiently obtaining high temperature and high pressure superheated steam while preventing high temperature corrosion of a boiler tube due to chlorine. Patent application (reference number 96
P0191). The basic invention is approximately 2
Steam water pressurized to have a boiling point of around 00 ° C. to 320 ° C. is used, the heating of the steam water is performed in a plurality of stages of at least two stages, and heating up to the above-mentioned boiling point temperature is performed with chlorine-containing heat energy. The heating is performed by dechlorination heat energy containing no chlorine to obtain superheated steam at a predetermined temperature from the substantially boiling point.

According to the basic invention, for example, as shown in FIG. 2, even if the waste such as municipal waste is pyrolyzed, for example, a chlorine-containing pyrolysis gas containing HCl or the like in the pyrolysis gas is generated. Since the steam water is heated by the thermal energy of the chlorine-containing pyrolysis gas to a boiling point of about 200 ° C. to 320 ° C., the chlorine-containing pyrolysis gas may act on the tube of the steam generating boiler. Since the tube surface temperature does not rise above 350 ° C, it does not corrode. In this case, the steam water has a boiling point of approximately 200 ° C. to 32 ° C. when pressurized.
Since there is a variation in the application of heat energy to the steam water of the chlorine-containing pyrolysis gas because it is set to around 0 ° C, it is due to absorption of the heat of the steam water (in other words, phase conversion from water to steam). Used only for and does not act as a temperature rise)
Therefore, it is possible to obtain steam water or steam having a stable heating temperature without the surface temperature of the heat exchange tube of the steam water rising above the chlorine corrosion temperature.

Since the undecomposed residue that has not been decomposed by the thermal decomposition at about 350 ° C. to 500 ° C. has already been dechlorinated, it can be obtained by burning it, for example, 500
Approximately 200 ° C. using heat energy of about 950 ° C.
Even if steam water or steam that is primarily heated to around 320 ° C is secondarily to thirdly heated to obtain heated steam of 400 to 500 ° C (boiler tube temperature is 450 to 550 ° C), tube corrosion does not occur. Even when power is generated by incineration by this, about 30 to 40, which is the same as in a plant that uses fuel oil or LNG containing almost no chlorine, as fuel.
Power generation efficiency of around% can be obtained.

A device for embodying the invention is a temperature of 300 ° C. or higher, preferably a temperature of 350 to 500.
The waste is supplied into the space of ℃ to carry out the thermal decomposition reaction,
Pyrolysis gas generated by the reaction and a char mixture composed of undecomposed residue and fluid medium and incombustibles are separated from each other, for example, a pyrolysis means using a fluidized bed, a rotary kiln, a screw stirring tank, or air or combustion exhaust gas. By burning the undecomposed residue while flowing the char mixture by means of a char combustion means consisting of, for example, a fluidized bed such as a high-speed fluidized bed or a bubbling fluidized bed, and directly or re-combusting the pyrolysis gas About 400
First steam producing means for producing hot water or steam having a temperature of not higher than 200 ° C., specifically about 200 to 320 ° C. and heat of the combustion gas obtained by the char combustion means are produced by the first steam producing means. It is characterized by including a second steam producing means for converting the hot water or the steam thus generated into superheated steam.

The present invention further develops such basic technology, and provides a superheated steam production apparatus capable of more efficiently reducing chlorine and obtaining superheated steam at high temperature as compared with the above-mentioned basic technology. is there. Another object of the present invention is to provide a preferred char combustion means applied to the above-mentioned basic technique, and in particular, an apparatus for producing superheated steam capable of efficiently combusting a char mixture. Another object of the present invention is to efficiently perform thermal decomposition in the thermal decomposition means, to prevent tar adhesion and coking of the thermal decomposition gas and to reduce dioxin and NOx, which is more efficient than the basic technology. It is an object of the present invention to provide an invention relating to the production of superheated steam, which is capable of obtaining a superheated steam at a high temperature and a high pressure, while well reducing chlorine.

[0009]

The present invention has a temperature of 300 ° C.
Pyrolysis means that separates the pyrolysis gas generated by the reaction and the char mixture consisting of undecomposed residue and the fluid medium and the incombustible material from each other by supplying the waste to the above space to perform the pyrolysis reaction, for example, A fluidized bed, a mechanical pyrolysis furnace (for example, a rotary kiln or a screw stirring tank), and a char mixture composed of the undecomposed residue and the fluidized medium taken out from the thermal decomposition means are combusted with the air while flowing with a char mixture. The present invention is applied to a superheated steam manufacturing apparatus that utilizes the heat of incineration of waste including one or a plurality of char burning means. (Thus, although it is preferably applied to the basic invention, it does not necessarily specify an apparatus including the first steam producing means and the second steam producing means.)

The invention according to claim 1 is a concrete embodiment of the char combustion means, which is characterized in that the char combustion means deposits the char mixture on the upper portion of the dispersion plate to form a fluidized bed. The air is supplied from the lower side of the dispersion plate (hereinafter referred to as an air flow) and / or the fluidized bed is provided with a circulation means for circulating the char mixture in the fluidized bed. This is because the char mixture supply port supplied from the thermal decomposition means is provided at the lower part of the downward flow region or the upward flow of the flow region. The circulation means may be divided into a plurality of parts so as to be able to flow in the fluidized bed, and the circulation means is constituted by a divided flow obtained by dividing an air flow supplied from below the dispersion plate into a plurality of parts. However, the flow rate of the char mixture in the fluidized bed may be controlled by the plurality of divided air streams so that the char mixture can be circulated, or both may be combined.

The operation of the invention is as follows. Since the char after pyrolysis is almost in a carbonized state, its density (specific gravity) is as light as 0.2 to 0.5. Therefore, when the char combustion means is formed in a fluidized bed, the Since the specific gravity is about 2.5, the char tends to float above the fluidized bed and is insufficiently mixed with air, resulting in poor combustibility and requiring a large amount of air. Therefore, in the present invention, since the char mixture supply port supplied from the thermal decomposition means is provided in the descending flow region of the circulating fluidized region, the char having a low specific gravity always moves to the bottom of the fluidized bed, and is circulated and fluidized with air. Is sufficiently mixed and a small air flow (for example, air ratio λ = (required air amount / theoretical air amount) = 1.2 to 1.3)
Will be sufficient for combustion. In particular, since the char floating on the surface of the fluidized bed is repeatedly moved to the bottom of the fluidized bed by the downward flow, the above effect is further enhanced.

The inventions according to claims 3 and 4 are inventions relating to the thermal decomposition means, and particularly the invention according to claim 5 is
1 in the upper space of the fluidized bed furnace which constitutes the thermal decomposition means
Alternatively, the introduction of air in multiple stages, characterized by performing a complete combustion of the pyrolysis gas, preferably a narrow passage area between the upper space and the fluidized bed space below it, to promote mixing with air and radiant heat. It is characterized by having a backflow prevention function.

As described above, the thermal decomposition means is 350-
Since the pyrolysis gas of 500 ° C. is generated, if the gas outlet temperature on the exit side of the pyrolysis means is lowered, the tar content thereof may be condensed and attached to the exit line.

Therefore, in the invention according to claim 3, air (including oxygen-enriched air) is introduced into the upper space of the fluidized bed furnace constituting the thermal decomposition means in one or a plurality of stages, and the thermal decomposition gas is generated. I'm trying to burn. As a result, it is possible to prevent a temperature drop in the outlet line and prevent the temperature from rising excessively to prevent tar from adhering or to prevent coking, thereby enabling stable operation.

Further, according to the present invention, it is preferable to further introduce air into the pyrolysis gas after the primary combustion of the pyrolysis gas to burn the pyrolysis gas in a reduced state to reduce NOx. Furthermore, when the heat at the time of re-combustion in the upper space is radiated to the fluidized bed space therebelow, char combustion or the like occurs, and preferable thermal decomposition does not occur. Therefore, the present invention narrows the passage area between the two spaces to promote mixing with air and to have a backflow prevention function for radiant heat.

According to a fourth aspect of the present invention, the thermal decomposition means comprises a fluidized bed, the inside of the fluidized bed is provided with a fluidized medium such as fluidized sand contained on a dispersion plate, and air is introduced from below the dispersion plate. Alternatively, the main fluidized bed, which fluidizes the fluidized medium by blowing combustion exhaust gas, and the lower side wall side of the main fluidized bed are widened, and the solid content is conveyed to the bottom from the waste input side to the char mixture extraction side. It is characterized in that it is provided with a transporting means.

According to the present invention, the carrying means functions as a sub-pyrolysis part, and in that part the unburned material is forcibly carried in the char residual direction to carry out the pyrolysis, so that the unburned material is contained in the non-combustible material. Unburned material can be prevented from remaining, and chlorine in the waste can be substantially completely decomposed and gasified and removed.

Particularly, according to the present invention, the partition plate provided in the fluidized bed allows the flow length of the fluidized bed to be substantially the same, specifically, the flow for pushing out toward the char mixture outlet while mixing the waste and the fluidized medium. The length can be made large, and since the waste does not blow through to the char mixture outlet, thermal decomposition is uniformly maintained for a predetermined time or longer.
Therefore, the thermal decomposition can be carried out uniformly and sufficiently as compared with the invention described in claim 1, and chlorine in the waste can be decomposed substantially completely and gasified to be removed.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, and are merely illustrative examples. It's just FIG.
2 and FIG. 2 relate to an overheated steam production apparatus utilizing incineration heat of waste according to an embodiment of the present invention, particularly an overheated steam production apparatus provided with a second char combustion means. In the figure, 1 is a pyrolysis furnace comprising a fluidized bed, in which a fluidized medium 2-1 such as fluidized sand is stored on a dispersion plate 3 such as a perforated plate, and a waste supply line 4 and a sand circulation (return) line. Fluid waste and waste such as municipal solid waste are put in from 5, and the combustion exhaust gas, etc. supplied from the combustion exhaust gas inlet line 6 (this pyrolysis furnace is basically a gas supplied for thermal decomposition, not for combustion). Most of the combustion exhaust gas consumes oxygen, but a small amount of air is added as necessary to control the temperature) to generate a fluidized bed space at a temperature of 300 ° C or higher, and perform a thermal decomposition reaction of the waste. The pyrolysis gas generated by the reaction is discharged from the pyrolysis gas outlet line 7, the char mixture consisting of undecomposed residue and fluidized sand is discharged from the char mixture extraction line 9, and the incombustibles are extracted from the incombustibles extraction line 8. Separate and take It is.

At this time, it is preferable to perform the thermal decomposition so that the thermal calorie ratio of the thermal decomposition gas and the char mixture becomes "about 7 (pyrolysis gas): about 3 (char mixture)". This is because if the steam water to be heated is pressurized to around 100 Kgf / cm ^2, its boiling point will be around 309 ° C.,
For the pyrolysis gas, the water-cooled wall boiler 36 and the first boiler 24
"Boiling point 309 ° C + latent heat of vaporization" of steam water from room temperature. In other words, calories that rise from room temperature to 309 ° C until almost vaporized, and steam that rises from boiling point 309 ° C to 500 ° C.
The ratio of calories to be launched is about 7: 3.

An air inlet line 21 is attached to the thermal decomposition gas outlet line 7 on the outlet side of the thermal decomposition furnace 1, and the thermal decomposition gas taken out from the thermal decomposition furnace 1 introduces air from the air inlet line 21. Then, tar and the like contained in the pyrolysis gas are partially burned to prevent tar from adhering to the outlet line 7 and prevent coking.

Further, at the downstream end of the outlet line 7, a pyrolysis gas combustion furnace 34 composed of a combustion duct is arranged, and air is supplied to the pyrolysis gas through a sufficient line 21 'to generate the pyrolysis gas. Completely burn.

Numeral 10 is a char combustion furnace consisting of a bubbling fluidized bed furnace, and a char mixture supplied from a char mixture take-out line 9 on a dispersion plate 11 arranged at the bottom, and a sand circulation line 19-2 / 19-1. The fluidized sand circulated between the auxiliary char combustion furnace 10B and the auxiliary char combustion furnace 10B is stored.

Air is supplied from the air supply line 12 below the dispersion plate 11 to 700-700 in the fluidized bed 2-3.
The undecomposed residue is burned by heating it to 800 ° C., and air is further introduced from the air supply line 13 in the middle region of the char combustion furnace 10 to heat it further to generate combustion gas at about 800 to 1300 ° C. The second super heater 29-1 and / or the water-cooled wall boiler 3 is provided in the upper region of the char combustion furnace 10.
6'is provided, and with the superheat of the superheated steam introduced from the second steam producing means (the first superheater 20) through the line 28-1, the combustion gas which becomes unnecessarily high around 950 to 1300 ° C. Drop to 800-950 ° C. Even if the combustion gas temperature is lowered to 800 to 950 ° C. as described above, the steam temperature in the first super heater 20 is 400 to 520.
There is no problem in maintaining at ℃. Then, the small incombustibles that are not burned in the char combustion furnace 10 are taken out from the incombustibles taking-out line 14.

On the other hand, the char combustion furnace 10 is additionally provided with a sub-char combustion furnace 10B as a sub-fluidized bed, and the sub-char combustion furnace 10B is provided via a sand circulation line 19-2 / 19-1.
And the fluidized sand is made to flow by the air introduced from the line 12 ', and the auxiliary char combustion furnace 1
The third super heater 29-2 is arranged in the fluid medium of 0B, and the line 28- is connected to the outlet side of the second super heater 29-1.
Connected via 2. The combustion gas obtained in the auxiliary char combustion furnace 10B is supplied to the char combustion furnace 1 through the line 19-3.
0 is supplied. The sub-char combustion furnace 10B may be provided independently, but as shown in FIG. 1, a fluid medium path 19-1 / for returning the fluid medium heated by the char combustion furnace 10 to the pyrolysis furnace 1 During 5, the third super heater 29-
It is advisable to interpose the auxiliary char combustion furnace 10B provided with No.2. 3-1 and 3-2 are dispersion plates.

The combustion gas heat-exchanged by the second super heater 29-1 is introduced from the sand / combustion gas outlet line 15 into a gas / solid separation device such as a cyclone 16, where dust and ash and combustion gas are separated. The separated combustion gas is introduced into the first super heater 20 through the gas outlet line 17.
20 is a first super heater and 24 is a first boiler.
In the boiler 24, the pyrolysis gas taken out from the pyrolysis gas outlet line 7 is burned in the combustion gas combustion furnace 34 in which the water-cooled wall boiler 36 is installed, and the first super heater 20.
Together with the combustion exhaust gas discharged from the boiler gas outlet 22 of No. 1, the boiler water introduced into the first boiler 24 and taken from the boiler water inlet 26 is heated to around 200 to 320 ° C.,
Steam or heated water is supplied to the first super heater 20 from the first boiler outlet line 27.

The boiler water is also introduced into the water-cooled wall boiler 36 in the combustion gas combustion furnace 34 through the branch line 26 'and supplies steam or heated water to the first super heater 20 through the branch line 27'. The steam water whose pressure is set to around 100 Kgf / cm ² and whose boiling point is set to around 309 ° C. is introduced into the water-cooled wall boiler 36 and the first boiler 24 to perform the first stage heating. However, the water flow rate is controlled so that the heating temperature is around 309 ° C., which is close to the boiling point. As a result, the tube surface wall temperature of the water-cooled wall boiler 36 and the first boiler 24 can be kept at 350 ° C. or lower by following the heated water, and the pyrolysis gas to be heat-exchanged contains chlorine or HCl. No corrosion will occur.

In the first superheater 20, steam / heated water taken out from the outlet lines 27, 27 'of the first boiler 24 and the water-cooled wall boiler 36 and heated by the water-cooled wall boiler 36 are taken out via the branch steam line 27'. Introduced steam / heated water and heated by the combustion gas supplied through the combustion gas line 17 to produce superheated steam of about 400 to 520 ° C., and the second from the steam outlet line 28-1 Introduced in series to the superheater 29-1, and further to the third superheater 29-2 from the line 28-2, respectively.
The superheated steam superheated to ˜520 ° C. is taken out and sent to the generator.

Although the operation of the above-described embodiment has already been described together with the constitution, it will be simply and repeatedly explained that the chlorine-containing organic compound such as vinyl chloride plastic is mixed in the waste such as municipal waste supplied to the thermal decomposition furnace 1. And about 0.2 to 0.5% of Cl is contained in the combustible content. Then, municipal waste is supplied from the waste supply line 4 and high-temperature circulating fluidized sand is supplied from the fluidized sand circulation line 5 to the pyrolysis furnace 1, respectively, and a slight temperature adjustment is made to the combustion exhaust gas from the lower air or the combustion exhaust gas inlet line 6. By treating at a temperature of 350 to 500 ° C. in a fluidized bed in which the working sand is supplied to fluidize the fluidized sand 2,
From the char mixture take-out line 9, an undecomposed residue containing substantially no chlorine is obtained. That is, the chlorine contained in the waste is substantially contained in the pyrolysis gas and is discharged to the pyrolysis gas outlet line 7.
The large incombustibles separated by the thermal decomposition reaction in the thermal decomposition furnace 1 are taken out of the furnace through the incombustibles extraction line 8. At this time, the thermal decomposition time and the thermal decomposition temperature are set so that the thermal calorie ratio of the thermal decomposition gas and the char mixture is about 7: 3.

The pyrolysis gas taken out from the pyrolysis outlet line 7 of the pyrolysis furnace 1 contains low-calorie gas, oil,
Although tar and HCl are contained, the air supplied from the air inlet line 21 of the pyrolysis furnace 1 is pre-combusted to burn or evaporate the tar portion, thereby preventing tar adhesion and coking in the outlet line 7. At the same time, a large amount of air is introduced into the pyrolysis combustion furnace 34 through the line 21 ′, and the pyrolysis gas is completely combusted in the pyrolysis combustion furnace 34. As a result, since the temperature of the pyrolysis gas in the pyrolysis combustion furnace 34 can be set high, a large amount of steam / steam water that is introduced into the water-cooled wall boiler 36 and the first boiler 24 and rises up to a boiling point of 200 to 320 ° C. can be produced. .

In the pyrolysis combustion furnace 34, a water-cooled wall boiler 36 is also provided.
The pyrolysis gas that has exchanged heat with is supplied from the first boiler gas inlet 23 to the first boiler 24 together with the combustion exhaust gas from the first super heater boiler gas outlet line 22. Since about 500 to 1000 ppm of HCl is contained in the gas introduced into the pyrolysis combustion furnace 34 and the first boiler 24, the flow rate of the boiler water is adjusted to adjust the water cooling wall boiler 36 and the first boiler 24. The tube surface temperature is about 350, which is the same as the conventional one.
C. or lower to suppress high-temperature corrosion. Therefore, high-temperature superheated steam cannot be obtained in the water-cooled wall boiler 36 and the first boiler 24, but since it can be heated up to about 200 to 320 ° C., it can be further heated to the super heaters 29-1 and 29- after the first super heater 20. If heated at 2, about 400-520
It is possible to obtain superheated steam at a high temperature of ° C.

The char mixture taken out from the char mixture take-out line 9 in the pyrolysis furnace 1 is composed of fluidized sand and undecomposed residue, and a char mixture containing substantially no chlorine,
In the combustion furnace 10, the air is supplied to the lower part of the combustion furnace 10 and burned by the air supplied from the air supply line 12 through the dispersion plate 11. In this case, the amount of air supplied from the air supply line 12 is adjusted so that the undecomposed residue is burned while flowing the fluidized sand. Air supply line 1 for complete combustion
3 or / and further air may be supplied from line 19-3. The temperature of the combustion furnace 10 rises due to the combustion exothermic reaction. This temperature value is the char mixture take-out line 9
Calorific value of undecomposed residue and air supply line 1
Depending on the amount and temperature of the air of 2 and 13 and the fluidized sand in the sand circulation line 19, the temperature may become as high as around 1000 to 1200 ° C.

Therefore, heat is exchanged with the superheated steam from the first superheater 20 through the line 28-1 by the second superheater 29-1, or the combustion gas is converted to 80 by the boiler.
It is easy to set the temperature to 0 to 950 ° C. The incombustibles reduced in size by melting glass, cans, and the like are extracted from the incombustibles take-out line 14.

On the other hand, a fluidized medium path 19-1 for returning the fluidized medium heated from the char combustion furnace 10 to the pyrolysis furnace 1
700-800 in the first char combustion furnace 10 by interposing the auxiliary char combustion furnace 10B provided with the third super heater 29-2 through the pressure difference forming means 50 in / 5.
The fluidized medium heated to 0 ° C. is absorbed by the third super heater 29-2 in the auxiliary char combustion furnace 10B to remove heat from 500 to 7
The temperature of the auxiliary char combustion furnace 1 is lowered to 00 ° C., and the heat of the auxiliary char combustion furnace 10B is removed by the third super heater 29-2 of the auxiliary char combustion furnace 10B.
0 to 500-700 ℃, 500-700 ℃
Since the fluidized medium dropped to the thermal decomposition furnace 1 can be returned to the thermal decomposition furnace 1 while preventing backflow by the pressure difference forming means 50, a gentle thermal gradient can be obtained, and as a result, the thermal decomposition temperature in the thermal decomposition furnace 1 can be increased. The temperature can be stably controlled from 350 ° C to around 500 ° C.

The fluidized medium, which has been deprived of heat by the third super heater 29-2 in the fluidized bed 2-2 of the auxiliary char combustion furnace 10B, is returned to the pyrolysis furnace 1 through the return line 5. The steam superheated by the third super heater 29-2 is sent to the generator through the line 28-3.

On the other hand, 800 to 9 produced in the char combustion furnace 10.
Combustion gas at a high temperature of 50 ° C. and substantially free of chlorine is introduced into the cyclone 16 via the combustion gas outlet line 15, if necessary, and dust and ash from the outlet line 18,
The exhaust gas is separated and taken out from the gas outlet line 17.

On the other hand, the high temperature exhaust gas at 800 to 950 ° C. taken out from the gas outlet line 17 of the cyclone 16 is introduced into the first super heater 20 and the first boiler 24.
Also, it is used to heat the steam / steam water of about 350 ° C. produced by the water-cooled wall boiler 36 into superheated steam.
Since the exhaust gas that has passed through the gas outlet line 17 contains substantially no chlorine, even if the boiler tube surface temperature of the first superheater 20 is set to 350 ° C. or higher, high temperature corrosion is significantly reduced. Therefore, the temperature of the fluid in the tube should be about 5
The temperature can be set to 00 to 600 ° C., and high-temperature superheated steam can be stably obtained from the first superheater boiler steam outlet 28.

In order to maintain the temperature of the pyrolysis furnace 1 above the predetermined temperature of 300 ° C. in the pyrolysis furnace 1, the oxygen amount of the flowing gas supplied from the combustion exhaust gas inlet line 6 is adjusted, in other words, the first boiler. A small amount of air is supplied together with the combustion exhaust gas from 24 and a part of the fluidized sand having a high temperature of about 500 to 700 ° C. from the auxiliary char combustion means 10B is fed into the pyrolysis furnace 1 through the return line (sand circulation line) 5. It is returned and used as a heat source.

For example, the air or combustion exhaust gas supplied to the pyrolysis furnace 1 through the combustion exhaust gas inlet line 6 is 350 to 5
Combustion exhaust gas that is low in oxygen (about 3 to 5%) and maintains a temperature of 150 to 200 ° C in order to efficiently perform thermal decomposition in the range of 00 ° C, specifically, the first boiler. It is preferable to use the combustion exhaust gas extracted from the outlet line 25 of 24.

FIG. 3 shows a structure of a fluidized bed obtained by improving the char combustion furnace. A char mixture is deposited on the upper part of the dispersion plate 11 to form a fluidized bed 2-3, and the fluidized bed 2-3 can be circulated. To the left and right and the center of the three flow areas 2-3A / 2-3B /
An upper partition plate 61A / 62A divided into 2-3C is disposed, and the upper partition plate 61A / 62A is opened at the upper part and the bottom part of the fluidized bed 2-3, respectively. A line for supplying the char mixture and the fluid medium to the char combustion furnace 10 from the pyrolysis furnace 1 side and the sub-char combustion furnace 10 side, respectively, in the flow area 2-3B in the center of the flow area partitioned by the upper partition plates 61A / 62A. 9 and line 19-2 are connected.

Further, the dispersion plate 11 is a non-combustible material take-out line 1
It is inclined downward toward the 4 side. In the space below the dispersion plate 11, lower partition plates 61B / 62B are arranged at the same intervals as the upper partition plates 61A / 62A, and the central part 11-2 of the dispersion plate sandwiched between the lower partition plates 61B and 62B.
Is more effective when formed in a mountain shape. Also, the dispersion plate 11-, which is partitioned by the lower partition plates 61B and 62B, respectively.
1 / 11-2 / 11-3 Branch lines 12-1 / 12- connected to the air supply line 12 at the bottom of the lower space, respectively.
2 / 12-3 are connected and the branch line 1
2-1 / 12-2 / 12-3 are each provided with a flow rate adjusting valve 64, which is configured to be able to control the air flow supplied to each flow region divided into three by the upper partition plates 61A / 62A. . A line 19-1 for supplying a fluid medium to the auxiliary char combustion furnace 10B is provided on the interface of the fluidized bed 2-3, and a line 19-3 for supplying a combustion gas from the auxiliary char combustion furnace 10B is provided above the interface. .

According to such an apparatus, the supply port of the line 9 for supplying the char mixture supplied from the pyrolysis furnace 1 is divided into three parts in the central part of the flow region 2-3B (downward flow region) or the left and right flow regions. Area 2-3A / 2-3C (upstream basin)
Dispersion plate 11-2 provided on the lower part of the
Is a flow region 2-3A / on both left and right sides of the central portion 2-3B.
Since it is formed in a mountain shape so that the air flow can flow in 2-3C, the air flow rate of 12-2 is set to be smaller than 12-1 / 12-3, and the flow region 2 located on both the left and right sides is formed.
-3A / 2-3C is supplied with an air flow upward from the branch line 12-1 / 12-3 below the dispersion plate 11-3 / 11-1, so that the central flow region 2-3B is provided. Is a descending basin, and the flow area is located on the left and right sides 2-3A / 2
-3C can be an upflow basin.

From the result line 9, for example, the central part of the flow region 2-3B (downflow region) or the flow region 2-3A / 2-3.
The char mixture supplied to the lower part of C (upward flow region) has an air flow flowing from the central portion 2-3B to the flow regions 2-3A / 2-3C on both left and right sides by the mountain-shaped dispersion plate 11-2. In the central part of the fluidized zone 2-3B, a downward flow of the fluidized medium can be formed, while on the other hand, the fluidized areas 2-3A / 2-3C located on both the left and right sides are an upward flow. The medium circulates as shown by the arrow in (A). As a result, char with a low specific gravity always moves to the bottom of the fluidized bed due to the descending flow region of the central region 2-3B of the fluidized region, and circulates through the fluidized regions 2-3A / 2-3C located on both the left and right sides. Is sufficiently mixed, and sufficient combustion is possible with a small air flow (for example, air ratio λ: 1.2 to 1.3). Also, for example, the char floating on the surface of the fluidized bed is repeatedly moved to the bottom of the fluidized bed by the downward flow, so that the above-mentioned effect is further enhanced.

On the other hand, the incombustibles which are not burned in the fluidized bed move along the downward inclination of the dispersion plate 11 as shown in (B) and (C) and pass through the guide plates 14-1 / 14-2. It is discharged from the take-out line 14 to the outside.

FIG. 4 is a trihedral view showing the internal structure of the pyrolysis furnace 1 according to the improvement of the embodiment of FIG. 1, (A) being a front sectional view,
(B) is a plan sectional view and (C) is a right side view. Inside the fluidized bed 1, specifically, a fluid medium such as fluidized sand contained on a dispersion plate is discharged from the waste input side (waste supply line 4 side) to the char mixture extraction side (char mixture extraction line 9 side). The partition plate 80 is divided into a plurality of steps toward each other, and the partition plate 80 is separated from the left and right side walls alternately on one side to form an opening 81.
The main fluidized bed portions 1A are formed by alternately providing 1s at different positions. Further, the lower side wall side of the main fluidized bed 1A is widened,
A conveying means for conveying the solid content from the waste input side to the char mixture take-out side, specifically, a screw type discharger 1C is provided at the bottom thereof, and the conveying means 1C is provided as necessary.
An air or combustion exhaust gas inlet line 82 for injecting air or combustion exhaust gas or the like is provided immediately below the auxiliary fluidized bed portion 1B for fluidizing fluidized sand or the like. Further, according to the thermal decomposition furnace 1, since the unburnt substances adhering to the incombustible substances by the transporting means 1C in the sub-combustion section 1B can be combusted while being forcibly transported in the char residual direction, The fuel can be discharged without remaining in the incombustible.

The partition plate 80 provided in the main fluidized bed portion 1A pushes out toward the char mixture take-out line 9 while mixing the substantial fluidized bed flow length, specifically, the waste and the fluid medium. Can take a long flow length,
Moreover, since the waste does not blow through to the char mixture take-out line 9, thermal decomposition can be carried out uniformly and for a predetermined time or longer. As a result, the thermal decomposition can be carried out uniformly and sufficiently, and chlorine in the waste can be decomposed substantially completely and gasified to be removed.

FIG. 5 relates to another improvement of the pyrolysis furnace in which the pyrolysis gas combustion furnace 34 consisting of the combustion duct shown in FIG. 1 is integrated. FIG. 5A shows the pyrolysis furnace and the combustion duct of FIG. FIG. 6B is a side view, FIG. 7B is a modified example of the diaphragm portion, and FIG. In this embodiment, in the fluidized bed furnace constituting the pyrolysis furnace 1, a combustion duct 4 is provided above the fluidized bed furnace via a throttle portion 411.
0 is formed, and the air diffuser nozzle 42 is attached to the throttle portion 411.
Further, an air introduction port 43 for introducing air is provided above the combustion duct 40.

As shown in FIGS. 5A and 5C, the throttle portion 411 is formed in a tapered shape from the upper space along the extending direction of the air diffuser nozzle 42 extending horizontally in the central area of the throttle portion 411. The outlet may be formed with a narrower width, or, as shown in (B), the throttle portion 411 is reduced in diameter so that a swirling airflow can be introduced into the reduced diameter portion. The air flow inlets 21, 21 may be provided at vertically symmetrical positions. The pyrolysis gas generated in the pyrolysis furnace 1 is drawn by the throttle unit 41.
1 is introduced into the combustion duct 40 through the air introduction line 21, is introduced from the air introduction line 21 and is ejected from the air diffuser nozzle 42, and the pyrolysis gas is primarily burned in a reducing atmosphere (air excess ratio 0.6 to 0). It is preferable to achieve low NOx and further to introduce air from the air introduction port 43 in the upper region to perform secondary combustion to achieve low CO and low dioxin by complete combustion.

Further, since the throttle portion 411 is provided between the combustion duct 40 and the thermal decomposition furnace 1, the mixing with air is promoted and the heat at the time of recombustion in the combustion duct 40 is radiated to the fluidized bed space therebelow. As a result, preferable thermal decomposition can be achieved in the thermal decomposition furnace 1 without causing char combustion or the like.

[0050]

As described above, according to the present invention, removal of incombustibles in the thermal decomposition means of waste and char combustion means and separation of the fluid medium are performed more efficiently, and stable thermal decomposition and char combustion are performed. You can Further, the present invention can provide a preferable char combustion means applied to the above-mentioned basic technique, particularly a char combustion means capable of efficiently combusting the char mixture. Further, the present invention can provide a preferable thermal decomposition means applied to the above-mentioned basic technique, particularly a thermal decomposition means capable of efficiently performing thermal decomposition of waste. Further, according to the present invention, while efficiently performing the thermal decomposition in the thermal decomposition means, it is aimed at preventing tar adhesion and coking of the thermal decomposition gas and reducing dioxin, CO and NOx, and comparing the basic techniques. As a result, it is possible to more efficiently reduce chlorine and obtain superheated steam at a high temperature. And so on.

[Brief description of drawings]

FIG. 1 is a system diagram showing an apparatus for producing superheated steam using heat of waste incineration according to a first embodiment of the present invention.

FIG. 2 is a graph showing a manufacturing procedure of superheated steam using incineration heat of waste according to the basic invention.

FIG. 3 shows a char combustion means applied to FIG.
(A) is a front view, (B) is a side view, and (C) is a plan view.

FIG. 4 is a trihedral view showing the internal structure of the pyrolysis furnace 1 according to the improvement of the embodiment of FIG. 1, (A) is a front sectional view, (B) is a plan sectional view, and (C) is a right side view. is there.

5 is related to another improvement of the thermal decomposition furnace in which the thermal decomposition gas combustion furnace 34 including the combustion duct shown in FIG. 1 is integrated,
(A) is the figure which looked at the thermal decomposition furnace and combustion duct of Drawing 1 from the side, (B) is a modification of a throttle part, (C) is a front view.

[Explanation of symbols]

 1 Pyrolysis Furnace (Pyrolysis Means) 10 Combustion Furnace (Char Combustion Means) 10B Second Combustion Furnace (Sub Char Combustion Means) 11 Dispersion Plate 20 First Superheater (Second Steam Production Means) 20-2 Third Superheater (Second steam producing means) 24 First boiler (first steam producing means) 29-1 Second super heater (second steam producing means) 34 Pyrolysis gas combustion furnace 36 Water-cooled wall boiler (first steam producing means) Means) 50 pressure difference forming means

Claims (4)

[Claims] 1. A waste material is supplied into a space having a temperature of 300 ° C. or higher to cause a pyrolysis reaction, and a pyrolysis gas generated by the reaction, a char mixture composed of an undecomposed residue and a fluid medium and an incombustible material are separated. A pyrolysis means for separating from each other, and one or more char combustion means for burning the undecomposed residue while flowing a char mixture consisting of the undecomposed residue and the fluidized medium taken out from the pyrolysis means by air. The char combustion means deposits a char mixture on the upper part of the dispersion plate to form a fluidized bed, and air or combustion exhaust gas flow (hereinafter referred to as air flow) supplied from the lower part of the dispersion plate or / and inside the fluidized bed, It is a fluidized vessel in which a circulation means for circulating and circulating the char mixture in a fluidized bed is formed, and a thermal decomposition means is provided at a lower part of a descending flow area or an upstream area of the circulating flow area. Superheated steam production apparatus utilizing the incineration heat of waste, characterized in that provided supply port al the supplied char mixture. 2. The circulating means is a divided flow obtained by dividing an air flow supplied from below the dispersion plate into a plurality of divided flows, and the plurality of divided air flows enable the char mixture in the fluidized bed to circulate. The flow rate control is performed, The claim 1 characterized by the above-mentioned.
Superheated steam manufacturing equipment that uses the incineration heat of the listed waste. 3. A waste material is supplied into a space having a temperature of 300 ° C. or higher to cause a thermal decomposition reaction, and a pyrolysis gas generated by the reaction, a char mixture composed of an undecomposed residue and a fluid medium and an incombustible material are separated. 1) is included in an upper space of a fluidized bed furnace which includes thermal decomposition means for separating from each other and which constitutes the thermal decomposition means.
Or, introducing air in multiple stages, characterized by performing complete combustion of the pyrolysis gas, preferably narrowing the passing area between the upper space and the fluidized bed space below it, promoting the mixing with air and radiant heat. A superheated steam manufacturing device that uses the heat of incineration of waste, which has a backflow prevention function. 4. A waste material is supplied into a space having a temperature of 300 ° C. or higher to cause a pyrolysis reaction, and a pyrolysis gas generated by the reaction, a char mixture composed of an undecomposed residue and a fluid medium and an incombustible material are separated. Including a thermal decomposition means for separating from each other, the thermal decomposition means is constituted by a fluidized bed, the inside of the fluidized bed is provided with a fluidized medium such as fluidized sand accommodated on a dispersion plate, and air or combustion is performed from below the dispersion plate. A main fluidized bed that fluidizes a fluidized medium by blowing in exhaust gas and the like, and a lower side wall side of the main fluidized bed is widened, and a solid component is conveyed to the bottom from the waste input side to the char mixture extraction side An apparatus for producing superheated steam using heat from incineration of waste, which is provided with means.