JP3477327B2 - Superheated steam production method and apparatus using waste incineration heat - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an invention relating to the production of superheated steam in which municipal waste, industrial waste, etc. are incinerated, steam is produced by the heat of the combustion exhaust gas, and the steam is used in, for example, a power plant. .

[0002]

2. Description of the Related Art Conventionally, a fluidized bed incinerator is often used as an incinerator for incinerating wastes such as municipal solid waste, and such an apparatus is housed on a dispersion plate (for example, a perforated plate) in a fluidized bed incinerator. By blowing air or incineration exhaust gas into the fluid medium such as sand from below the dispersion plate, the fluidized medium is fluidized and heated, and waste such as municipal solid waste is put into the fluidized bed thus formed. To burn. Combustion gas generated by this combustion reaches a boiler through 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.

A chlorine-containing organic compound such as vinyl chloride plastic is mixed in the waste such as municipal waste, and the combustible content thereof is about 0.2 to 0.5% as C1. And chlorine contained in PVC plastics mixed in waste such as municipal waste becomes HC1 by combustion (normally, HC1 in municipal waste combustion exhaust gas is about 500 to 1).
000ppm), and acts on the tube of the steam generating boiler installed downstream of the incinerator to corrode it. Particularly when the tube surface temperature is about 350 ° C. or higher, high temperature corrosion becomes remarkable as the temperature increases. Therefore, in the past, the tube surface temperature had to be 350 ° C. or lower, and the temperature of the vapor produced was limited to about 300 ° C. As a result, the power generation efficiency of the conventional waste incineration is about 15% or less, and the power generation efficiency of the plant that can make the boiler tube temperature 500 to 600 ° C. is about 30 to 40 with heavy oil or LNG containing almost no chlorine as fuel. It is remarkably low as compared with%, and its improvement has been strongly desired.

In order to solve such a problem, the applicant of the present invention has previously proposed a superheated steam producing apparatus utilizing the heat of incineration of waste as shown in FIG. (Japanese Patent Application No. 8-69090, etc.) The structure thereof will be described with reference to the drawings. FIG. 5 shows a superheated steam manufacturing apparatus utilizing the incineration heat of waste according to the prior application technology, in which 1 is a fluidized bed. In a thermal decomposition furnace, a fluidized medium 2-1 such as fluidized sand is stored on a dispersion plate 3-1 such as a perforated plate, and fluidized sand and municipal solid waste are fed from a waste supply line 4 and a sand circulation (return) line 5. Waste gas, etc., that was introduced from the combustion exhaust gas inlet line 6 (gas is supplied as combustion exhaust gas that consumes oxygen because this pyrolysis furnace is basically not for combustion but for thermal decomposition) Is mostly
(A small amount of air is added to control the temperature)
To generate a fluidized bed space at a temperature of 300 ° C. or higher, and to cause a thermal decomposition reaction of waste, and the thermal decomposition gas generated by the reaction is discharged from the thermal decomposition gas outlet line 7 and a char consisting of undecomposed residue and fluidized sand. The mixture is taken out from the char mixture taking-out line 9 and the incombustible is taken out from the non-combustible taking-out line 8 separately from each other.

The pyrolysis gas from the pyrolysis gas outlet line 7 is introduced into the ash melting furnace 31. The ash-melting furnace 31 introduces air or oxygen-enriched air into the ash-melting furnace 31 together with the pyrolysis gas through a line 30 while swirling and separating the ash by a swirling flow. The ash content is melted at 1300 ° C. or higher by means of the above method, and the melted ash content is dropped into the water reservoir 32A through the molten ash outlet line 32 to generate a water-cooled slug of about several mm, and the slag is used as a building aggregate. Configure to use effectively. In addition, the ash melting furnace 31 is introduced with a non-combustible substance in the line 14 and / or a bag filter, ash collected by an electric dust collector, etc. through a dust line 29.

Further, at the downstream end of the outlet line 33 of the ash melting furnace 31, a pyrolysis gas combustion furnace 34 consisting of a combustion duct is provided.
Is provided and a sufficient amount of air for the pyrolysis gas is supplied to the line 21.
It is supplied from A to completely burn the pyrolysis gas. Therefore, according to the present embodiment, the ash separated by the cyclone 16 and / or the incombustibles in the line 14 and / or the ash collected by the bag filter or the electrostatic precipitator is introduced into the ash melting furnace 31 to obtain the molten ash. It is possible to manufacture aggregates and the like. Further, ash and the like are not mixed in the pyrolysis gas that is introduced into the pyrolysis gas combustion furnace 34 and the first boiler 24, and stable steam production is possible over a long period of time.
Further, since the temperatures of the pyrolysis gas combustion furnace 34 and the first boiler 24 can be set high to about 800 to 900 ° C. (around 950 ° C. at the maximum), a larger amount of boiler water / steam produced by the boiler or the like is produced. it can.

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 and heated to 700 to 800 ° C. in the fluidized bed 2-3 to burn the undecomposed residue (char), and further to the middle region of the char combustion furnace 10. Air is introduced from the air supply line 13 of the above to completely combust and generate combustion gas of about 800 to 1300 ° C., and the second super heater 29-1 or / and the boiler are provided in the upper region of the char combustion furnace 10. 36-2 is provided, along with the superheat of the superheated steam introduced through the line 28-1 from the second steam manufacturing process (first super heater 20),
The combustion gas temperature, which has risen unnecessarily around 950 to 1300 ° C, is lowered to 800 to 950 ° C. Even if the combustion gas temperature is lowered to 800 to 950 ° C as described above, there is no problem in maintaining the steam temperature in the first superheater 20 at 400 to 520 ° C. Then, the incombustibles 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 third super heater 2 in the fluid medium of the auxiliary char combustion furnace 10B.
9-2 is arranged and is connected to the outlet side of the second super heater 29-1 via a line 28-2. The auxiliary char combustion furnace 10B may be provided independently.

The combustion gas heat-exchanged by the second superheater 29-1 is introduced from a sand / combustion gas outlet line 15 into a gas / solid separation device, for example, a cyclone 16 if necessary, where it is combusted with dust and ash. Gas is separated from the gas, and the combustion gas is introduced into the first super heater 20 through the gas outlet line 17.

Reference numeral 20 is a first superheater and 24 is a first boiler. The pyrolysis gas taken out from the pyrolysis gas outlet line 7 is burned in a combustion gas combustion furnace 34 in which a water-cooled wall boiler 36 is installed. Along with the combustion exhaust gas discharged from the boiler gas outlet 22 of the first superheater 20, the first
The boiler water introduced into the boiler 24 and heated from the boiler water inlet 26 is heated to around 300 ° C., and steam or heated water is supplied from the first boiler outlet line 27 to the first super heater 20. Boiler water is also introduced into the water-cooled wall boiler 36 in the combustion gas combustion furnace 34 via the branch line 26 'and supplies steam or heated water to the first super heater 20 via the branch line 27'. The boiler 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 temperatures of the water-cooled wall boiler 36 and the first boiler 24 can be maintained at around 309 ° C. following the heated water, and the heat-exchanged pyrolysis gas contains chlorine or HCl. Also, it is a low grade material and corrosion hardly occurs.

In the first superheater 20, steam / heated water taken out from the outlet lines 27 and 27 'of the first boiler 24 and the water-cooled wall boiler 36 and heated by the water-cooled wall boiler 36 and taken out through the branch steam line 27'. Steam / heated water is introduced and heated by the combustion gas supplied through the combustion gas line 17 to produce superheated steam of about 400 to 550 ° C., and then the second super heater from the steam outlet line 28-1. No. 29-1 and then from the line 28-2 to the third super heater 29-2 in series, respectively, and 400
Take out the superheated steam heated to ~ 550 ° C and
It is sent to the generator from 8-3.

[0012]

According to such prior art, by efficiently combining the pyrolysis furnace, the char combustion furnace, the boiler and the super heater, it is possible to reduce chlorine and obtain superheated steam at high temperature. However, there is a large amount of water in the domestic waste containing the garbage that is put into the pyrolysis furnace, and the pyrolysis gas obtained in the pyrolysis furnace is caused by the evaporated water from the water-containing waste. As a result of dilution, calorie reduction will occur, and in order to raise the temperature of the ash melting furnace to 1300 ° C. or higher, as a pyrolysis gas combustion air source,
The need to use 50% oxygen enriched air results in a significant increase in oxygen enrichment equipment and its operating power costs. The present invention is
It is an object of the present invention to eliminate the drawbacks of the prior application technique.

[0013]

The invention according to claim 1 is
The heating of the boiler water and at least two or more stages of multiple stage, pyrolysis obtained by thermal decomposition step of supplying the waste into the space out the thermal decomposition reaction including Jo Tokoro temperature above the fluidized medium
A temperature of about 400 ° C or less using the combustion heat energy of gas
One or more first steam producers that produce water or steam
And the char mixture consisting of the undecomposed residue and the fluidized medium taken out from the thermal decomposition step is combusted with air or combustion exhaust gas while flowing the undecomposed residue.
The thermal energy obtained by the char burning process
The hot water or steam produced in the first steam production process
And one or more second steam manufacturing process for the hot vapor, the
The waste that is put into the pyrolysis process is obtained from the char combustion process
And a drying step of drying using the high temperature sand,
Between the pyrolysis step and the first steam production step, the heat
Due to the primary combustion heat of the cracked gas, the char combustion process
Is separated from each gas extracted from the pyrolysis process
Ash melting and separating step for melting and separating the ash
The thermal decomposition gas is used as the thermal energy of the ash melting and separating process.
And is burned in the ash melting and separating process.
Energy of the pyrolysis gas and moisture obtained in the drying process
The method for producing superheated steam using the heat of incineration of waste is characterized in that the gas is supplied to the first steam production step .

The effect of multi-step heating is as described in the above-mentioned Japanese Patent Application No. 8-69.
067, for example, as shown in FIG. 5, even if chlorine-containing pyrolysis gas in which HCl or the like is contained in the pyrolysis gas by thermally decomposing waste such as municipal waste, The boiler water is heated by the thermal energy of the chlorine-containing pyrolysis gas at a boiling point of approximately 200 ° C to 320 ° C. Therefore, even if the chlorine-containing pyrolysis gas acts on the tube of the steam generating boiler, the tube surface It does not corrode because the temperature does not rise above 350 ° C. in this case,
The boiler water has a boiling point of approximately 200 ° C. to 320 ° C. when pressurized.
Since it is set before and after, even if there is a variation in the application of thermal energy to the boiler water of the chlorine-containing pyrolysis gas, it is the absorption of the heat of the boiler water (in other words, phase conversion from water to steam It is used only and does not act as a temperature rise), so that the boiler water or steam with a stable heating temperature can be obtained without the surface temperature of the heat exchange tube of the boiler water rising above the chlorine corrosion temperature. Can be done.

Since the undecomposed residue that has not been decomposed by the thermal decomposition at about 300 ° C. to 500 ° C. has already been dechlorinated, it can be obtained by burning it, for example, 500
Approximately 200 ° C. by utilizing heat energy of about 950 ° C.
There is no risk of tube corrosion even if the boiler water or steam that has been primarily heated to approximately 320 ° C is secondarily to thirdly heated to obtain heated steam of 400 to 500 ° C (boiler tube temperature is approximately 450 to 550 ° C). . Even when power is generated by incineration by this, the same 30 to 4 as in the plant that uses heavy oil or LNG containing almost no chlorine as fuel.
Power generation efficiency of 0% can be obtained.

Therefore, in order to achieve the above-mentioned action, the thermal decomposition is carried out so that the thermal calorie ratio of the thermal decomposition gas and the char mixture is "about 7 (pyrolysis gas): about 3 (char mixture)". preferable. This is one boiler water to be heated
Pressurize around 00Kgf / cm ² and set its boiling point to 309 ℃.
Since they are set before and after, the pyrolysis gas causes the boiler water to have a boiling point of 309 from the room temperature in the water-cooled wall boiler 36 and the first boiler 24 (both are referred to as the first steam manufacturing process (means)) shown in FIG. In other words, the ratio of the calories raised to almost vaporize at 309 ° C. and the calories raised from the boiling point of 309 ° C. to 500 ° C. is about 7: 3.

The present invention solves the above-mentioned problems and provides a high temperature obtained by the char combustion step by sufficiently drying the waste material introduced into the pyrolysis step by utilizing the high temperature sand obtained by the char combustion step. It has been found that the sand can be easily dried because it has a sufficient size both in terms of temperature and heat capacity.

[0018]

According to this invention, the ash can be easily melted by utilizing the high-calorie pyrolysis gas and air 1300.
The temperature can be raised to ℃ or higher. The thermal energy of the pyrolysis gas of 1300 ° C. or higher burned in the ash melting / separating step is not directly discarded, but the water-cooled wall boiler 3 is used.
6 and the first boiler 24. It is preferable that the moisture gas obtained in the drying step completely burns harmful components and odorous components in a pyrolysis gas combustion furnace.

The invention according to claim 2 is 100 to 300 ° C.
For drying waste at low temperature, preferably under oxygen deficiency
And dry it in the space with a temperature of 300 ° C or higher by the drying means.
The dried waste is supplied to carry out the thermal decomposition reaction,
Pyrolysis gas generated by reaction and undecomposed residue and flow
Separation of char mixture of media and incombustibles from each other
Pyrolysis means and undecomposed, taken out from the pyrolysis means
The char mixture consisting of the residue and the fluid medium is aerated with air.
Char that burns the undecomposed residue while flowing
Utilizes combustion means and combustion heat energy of the pyrolysis gas
To produce hot water or steam of about 400 ° C or less
The plurality of first steam producing means and the char combustion means are used.
With the heat energy obtained by the first steam producing means,
One or more that uses manufactured hot water or steam as superheated steam
Second steam producing means of the
The first combustion of the pyrolysis gas between the first and second steam producing means.
It is removed from char combustion means or pyrolysis means by burning heat.
Melt separation of ash separated from each gas discharged
A means for melting and separating ash is provided, and the pyrolysis gas is fed to the ash.
Together to perform ash melting fed to a separatory melt separation unit, wherein
Combustion gas of pyrolysis gas burned by ash melting and separation means
The moisture gas obtained by the drying means is used to produce the first vapor
It is characterized by being introduced into means .

If the drying temperature of the above-mentioned municipal waste is 300 ° C. or higher, hydrocarbon gas is generated, which is not preferable.
At below 00 ° C, sufficient evaporation cannot be achieved. A dry atmosphere is preferable because low temperature combustion does not occur in the absence of oxygen. Therefore, it is preferable that the drying means has the same structure as the thermal decomposition means and that only the temperature is controlled. That is, it is preferable that the drying means is also a fluidized bed, a kiln, or a horizontal stirring tank for drying the waste by using the high temperature sand obtained from the char combustion means similar to the thermal decomposition means. Effective use of heat energy can be achieved.

[0022]

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be exemplarily described in detail below with reference to the drawings. However, unless otherwise specified, 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 thereto, but are merely illustrative examples. Only. 1 shows an apparatus for producing superheated steam using incineration heat of waste according to an embodiment of the present invention. The same reference numerals as those shown in FIG. 5 refer to the same members, and only the portions different from those in FIG. 5 will be described. In the figure, 1A and 1B are a pyrolysis furnace and a drying furnace, respectively, each of which comprises a fluidized bed, in which a fluidized medium 2-1 such as fluidized sand is stored on a dispersion plate 3-1 such as a perforated plate. Waste such as municipal waste from the waste supply line 4, char combustion furnace 10 or auxiliary char combustion furnace 1
600-700 from 0B sand circulation (return) line 5-2
High temperature fluidized sand of ℃ was injected into each, and combustion exhaust gas supplied from the combustion exhaust gas inlet line 6-2 etc. (This drying furnace is basically dry under oxygen shortage, so the supplied gas is oxygen. Most of the exhaust gas is consumed, but it is the same as in a pyrolysis furnace in which a small amount of air is added to control the temperature if necessary.) Flow at a temperature of 100 to 300 ° C, preferably 100 to 250 ° C The floor space is generated, the waste is dried, and the moisture gas generated by the evaporation is introduced from the outlet line 7-2 into the pyrolysis gas combustion furnace 34 'in which the water-cooled wall boiler 36 is housed.

The dried waste mixture consisting of the dried waste and the fluidized sand is introduced into the pyrolysis furnace 1A through a line 9-2. On the other hand, in the pyrolysis furnace 1A, line 9-2
The dry waste mixture and the high-temperature fluidized sand of 600 to 700 ° C. are respectively introduced from the sand circulation (return) line 5-1 of the char combustion furnace 10 or the sub-char combustion furnace 10B, and the combustion exhaust gas inlet line 6-1. The dry waste heated to a temperature of 100 to 300 ° C. by the combustion exhaust gas supplied from the above produces a fluidized bed space of 350 to 500 ° C. to cause a thermal decomposition reaction of the waste, and the thermal decomposition generated by the reaction. The gas is introduced into the ash melting furnace 31 through the pyrolysis gas outlet line 7-1. The char mixture consisting of undecomposed residue and fluidized sand is taken out from the char mixture take-out line 9 to the char combustion furnace 10 and the incombustible is taken out from the non-combustible take-out line 8 from each other.

The operation of the above-mentioned embodiment will be briefly repeated below. The drying furnace 1B includes the above-mentioned auxiliary char combustion furnace (third embodiment).
Super heater) 10B to fluid sand circulation line 5-2
The circulating fluidized sand of 600 to 700 ° C. is supplied through it, while the water-containing waste such as municipal solid waste is supplied from the waste supply line 4, and further the lower air or combustion exhaust gas inlet line 6
-2 for supplying temperature control air to the combustion exhaust gas to cause the fluidized sand 2-1 to flow, and the temperature inside the drying furnace is set to 100
After drying at ˜250 ° C., the dried waste mixture consisting of the dried waste and the fluidized sand is line 9-2.
It is introduced into the thermal decomposition furnace 1A. Moisture gas generated by the drying is discharged from the outlet line 7-2 to the water-cooled wall boiler 36.
Is introduced into the pyrolysis gas combustion furnace 34 '. By the way, a chlorine-containing organic compound such as vinyl chloride plastic is mixed in the waste such as the municipal waste mentioned above, and the combustible content contains about 0.2 to 0.5% of C1. And line 9
-2 from the dry waste mixture and the fluidized sand circulation line 5-1 to circulate fluidized sand at 600 to 700 ° C. to the pyrolysis furnace 1A, respectively, and to produce flue gas from the lower air or flue gas inlet line 6-1. If necessary, temperature control air is supplied to fluidize the fluidized sand 2-1 in the fluidized bed, and temperature 3
By performing the treatment at 50 to 500 ° C., an undecomposed residue containing substantially no chlorine is obtained from the char mixture take-out line 9.

That is, substantially all the chlorine contained in the waste is contained in the pyrolysis gas and discharged to the pyrolysis gas outlet line 7-1. The large incombustibles separated by the thermal decomposition reaction in the thermal decomposition furnace 1A are taken out of the furnace through the incombustibles extraction line 8. The pyrolysis gas obtained by the pyrolysis furnace is supplied to the ash melting furnace 31 via line 7-1. This makes line 7-
Since the pyrolysis gas of No. 1 is not diluted with moisture gas, it becomes high calorie gas, and the temperature of the ash melting furnace 31 can be easily adjusted to 1300 to 1
It can be 500 ° C.

In the ash melting furnace 31, the outlet line 1 of the cyclone 16 together with the pyrolysis gas as described above.
8 / Ash of combustion gas and / or incombustibles in the line and / or bag filter ash is introduced through the dust line 29, and air or oxygen-enriched air introduced from the line 30 is burned together with the pyrolysis gas. Then, the ash is melted, and the melted ash is dropped into the water reservoir 32A to generate a water-cooled slug of about several mm, and the slug is used as a building aggregate. At the downstream end of the outlet line 33 of the ash melting furnace 31, a pyrolysis gas combustion furnace 3 including a combustion duct is installed.
4'is provided, and while introducing moisture gas from the drying furnace 1B, sufficient air is supplied to the pyrolysis gas from the line 21A to perform further complete combustion of the pyrolysis gas.

The combustion gas that has exchanged heat with the water-cooled wall boiler 36 in the pyrolysis gas combustion furnace 34 'is transferred 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. Supply. Since HC1 is contained in the gas introduced into the pyrolysis gas combustion furnace 34 'and the first boiler 24 in an amount of about 500 to 1000 ppm, the flow rate of boiler water is adjusted to adjust the water-cooled wall boiler 3
6 and the tube surface temperature of the first boiler 24 are set to about 350 ° C. or lower, which is the same level as the conventional one, 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
High temperature superheated steam of ~ 550 ° C can be obtained.

The char mixture taken from the char mixture take-out line 9 in the pyrolysis furnace 1A is a char mixture consisting of fluidized sand and undecomposed residue and containing substantially no chlorine, and is supplied to the lower portion of the char combustion furnace 10. Combustion is performed 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 and the undecomposed residue is burned while the fluidized sand 2-3 is fluidized. Further air may be supplied from the air supply line 13 and / or the line 19-3 for complete combustion. The temperature of the char combustion furnace 10 rises due to the combustion exothermic reaction. This temperature value is the calorific value of the undecomposed residue supplied from the char mixture extraction line 9 and the air and sand circulation lines 19-2 of the air supply lines 12 and 13,
19-1 depends on the amount and temperature of the fluidized sand
The temperature may be as high as 0 to 1300 ° C. Therefore, it is easy to bring the combustion gas to 600 to 950 ° C. by exchanging heat with the superheated steam from the first super heater 20 through the line 28-1 by the second super heater 29-1. The incombustibles that have been reduced in size by melting glass, cans, etc. are extracted from the incombustibles extraction line 14.

Since the fluid medium of the char combustion furnace 10 circulates between the pyrolysis furnace 1A and the drying furnace 1B, the temperature of the fluid medium of the char combustion furnace 10 is about 600 to 850 ° C. The temperature of the fluidized medium of 1 A is 350 to 500 ° C.,
The temperature of the fluidized medium in the drying furnace 1B is 150 to 300 ° C., and if the auxiliary char combustion furnace (third super heater) 10B is provided independently as shown in FIG. The fluidized medium of the combustion furnace 10 is used as a pyrolysis furnace 1A.
If it is directly introduced into the drying furnace 1B side, there is a possibility that the temperature in the thermal decomposition furnace 1A and the drying furnace 1B may rise due to the heat drop or heat fluctuation may occur, so that the amount of the fluid medium to be returned may be adjusted. It becomes complicated.

Therefore, as shown in FIG. 1, the third super heater 29-2 is provided in the fluid medium path 19-1 / 5 for returning the fluid medium 2-3 heated from the char combustion furnace 10 to the pyrolysis furnace 1A. 700 to 80 in the first char combustion furnace 10 by interposing the auxiliary char combustion furnace 10B provided with
The fluidized medium 2-3 heated to 0 ° C. is absorbed by the third superheater 29-2 in the sub-char combustion furnace 10B to generate 6
Since the fluidized medium 2-2 dropped to 00 to 700 ° C. and dropped to 600 to 700 ° C. can be returned to the thermal decomposition furnace 1A and the drying furnace 1B, a gentle heat gradient is possible,
As a result, it is possible to stably control the thermal decomposition temperature in the thermal decomposition furnace 1A at 350 to 500 ° C and the drying furnace temperature at around 100 to 250 ° C. The auxiliary char combustion furnace 10B
Has a third super heater 29-2 installed therein, which helps stabilize the temperature of the char combustion furnace. On the other hand, if the heat removal fluctuation from the third super heater 29-2 is large, this heat removal causes Temperature fluctuation may occur easily. In this case, FIG. 2 is advantageous.

On the other hand, 800 to 9
Combustion gas having a high temperature of 50 ° C. and containing substantially no chlorine is introduced into the cyclone 16 through the combustion gas outlet line 15, dust and ash are separated from the outlet line 18, and exhaust gas is separated from the gas outlet line 17 and taken out. Be done.
Then, the high temperature ash taken out from the outlet line 18 is fed to the ash melting furnace 31 described above.

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.
It is also used to heat steam / boiler water of about 200 to 320 ° C. produced by the water-cooled wall boiler 36 into superheated steam. Since the exhaust gas coming through the gas outlet line 17 contains substantially no chlorine, the first super heater 20
Even if the surface temperature of the boiler tube is 350 ° C. or higher, high temperature corrosion is significantly reduced, and a low grade material can be used.
Therefore, the temperature of the fluid in the tube is about 400-550 ° C.
Can be the first super heater boiler steam outlet 2
A high-temperature superheated steam is stably obtained from 8-1.

In order to maintain the temperature of the pyrolysis furnace 1A and the drying furnace 1B at a predetermined temperature, the combustion exhaust gas inlet line 6-
1, 6-2 adjust the oxygen amount of the flowing gas, in other words, while slightly supplying air with the combustion exhaust gas that has passed through the gas outlet line 25 of the first boiler 24,
A part of the fluidized sand having a high temperature of about 500 to 700 ° C. from the auxiliary char combustion furnace 10B is supplied from the sand circulation line 5 as a heat source. Incidentally, 11, 3-1, 3-2 are dispersion plates, 2-1, 2
-2 and 2-3 are fluidized beds.

FIG. 3 shows another embodiment in which the thermal decomposition furnace and the drying furnace are constituted by mechanical stirring means 1A1, 1B1 such as a kiln. In the drying furnace 1B1, waste such as municipal waste is discharged from the waste supply line 4. In the space of 100 to 300 ° C., the high temperature fluidized sand of 600 to 700 ° C. is introduced into the inlet side from the sand circulation (return) line 5-2 of the char combustion furnace 10 or the auxiliary char combustion furnace 10B, respectively. The waste is dried while being stirred / conveyed with, and the moisture gas generated by the evaporation is introduced from the outlet side line 7-2 into the pyrolysis gas combustion furnace 34 'in which the water-cooled wall boiler 36 is housed. Then, the dried waste mixture consisting of the dried waste and the fluidized sand is introduced from the outlet side line 9-2 into the pyrolysis furnace 1A1 similarly constituted by a kiln.

In the pyrolysis furnace 1A1, the dry waste mixture flows from the line 9-2, and the high temperature flow of 600 to 700 ° C. from the sand circulation (return) line 5-1 of the char combustion furnace 10 or the sub-char combustion furnace 10B. Each of the sands is introduced into the inlet side, and the thermal decomposition reaction of the waste is performed while stirring / conveying in the space of 350 to 500 ° C., and the thermal decomposition gas generated by the reaction is the line 7-on the thermal decomposition gas outlet side. 1 is introduced into the ash melting furnace 31. In addition, the char mixture composed of undecomposed residue and fluidized sand is taken out from the char mixture take-out line 9 on the outlet side to the char combustion furnace 10, and the incombustible is taken out from the non-combustible matter take-out line 8 below the outlet. It is configured. The pyrolysis and drying furnace may be configured using a horizontal stirring reactor, a screw feeder type reactor, or a horizontal reactor in addition to the above-mentioned kiln.

[0037]

As described above, according to the first and third aspects of the invention, the waste to be put into the thermal decomposition step is sufficiently dried by using the high temperature sand obtained from the char combustion step. High calorie and stable pyrolysis gas can be obtained, and since the high temperature sand obtained from the char combustion process is used as a heat source, it can be dried with sufficient size both in terms of temperature and heat capacity. Is.

According to the second and fourth aspects of the present invention, it is possible to raise the temperature to 1300 ° C. or higher at which ash can be easily melted by utilizing the high-calorie pyrolysis gas and oxygen-enriched air. And 130 burnt in the ash melting and separating process.
A large heat capacity can be obtained by not introducing the thermal energy of the pyrolysis gas at 0 ° C. or higher as it is, but also introducing the moisture gas obtained in the drying step into the steam producing step on the low temperature side. Further, according to the present invention, in any of the above steam producing apparatuses, it is possible to stably produce steam for a long period of time. Further, according to the present invention, the ash obtained by separating the pyrolysis gas or the combustion gas can be melted to produce an aggregate or the like.

[Brief description of drawings]

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

FIG. 2 is a system diagram showing an overheated steam production apparatus using incineration heat of waste according to a modification of FIG.

FIG. 3 is a pyrolysis furnace and a drying furnace used in the system of FIGS. 1 and 2, which is configured by a mechanical stirring means such as a kiln instead of a fluidized bed.

FIG. 4 is a graph showing the procedure for producing superheated steam using the heat of incineration of waste according to the basic configuration of the present invention.

FIG. 5 is a system diagram showing an overheated steam manufacturing apparatus using the heat of incineration of waste according to the prior application technology.

[Explanation of symbols]

1A, 1A1 Pyrolysis furnace 1B, 1B1 Drying furnace 10 Char combustion furnace 10B Sub char combustion furnace 20 1st super heater (2nd steam manufacturing means) 24 1st boiler (1st steam manufacturing means) 29-1 2nd super heater (Second Steam Manufacturing Means) 29-2 Third Super Heater (Second Steam Manufacturing Means) 31 Ash Melting Furnace 34 'Pyrolysis Gas Combustion Furnace 36 Water-cooled Wall Boiler (First Steam Manufacturing Means)

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hirotoshi Horizoe 1-8-1 Sachiura, Kanazawa-ku, Yokohama City Mitsubishi Heavy Industries Ltd. Yokohama Research Laboratory (72) Yoshihito Shimizu 1-8-1 Sachiura, Kanazawa-ku, Yokohama Mitsubishi Heavy Industry Co., Ltd. Yokohama Research Laboratory (56) Reference JP-A-5-346204 (JP, A) JP-A-53-97271 (JP, A) JP-A-50-43766 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F23G 5/46 F23G 5/00 115 F23G 5/027 F23G 5/04 F23G 5/16 F22B 1/18 F23J 1/00

Claims (3)

(57) [Claims] 1. Heating of boiler water in at least two stages
Multiple stages of, Place Supply the waste into the space containing the fluidized medium above a certain temperature.
Obtained in the thermal decomposition processPyrolysis gas
Using the combustion heat energy of
Or a plurality of first steam manufacturing steps for manufacturing steam
When, Undecomposed residue and flow taken from the pyrolysis process
The char mixture consisting of the medium is supplied to the air or flue gas.
Burning the undecomposed residue while flowingChar
Due to the heat energy obtained by the combustion process, the first
Hot water or steam produced in the steam manufacturing process of
One or more second steam manufacturing processesWhen,The waste that is put into the thermal decomposition process is called the char combustion process.
Drying process using the high temperature sand obtained.
See Between the pyrolysis step and the first steam production step, the heat
Due to the primary combustion heat of the cracked gas, the char combustion process
Is separated from each gas extracted from the pyrolysis process
Ash melting and separating step for melting and separating the ash
The thermal decomposition gas is used as the thermal energy of the ash melting and separating process.
And use Thermal energy of the pyrolysis gas burned in the ash melting and separating process
Rugie and the moisture gas obtained in the drying process are used to
To supply to the steam manufacturing process of No. 1 Characteristic waste burning
Superheated steam manufacturing method using heat rejection. 2.Preferably an acid at a temperature of 100-300 ° C
Means to dry the waste under a shortage of resources, Dry in the space with a temperature of 300 ° C or higher by the drying means.
The generated waste is supplied to cause the thermal decomposition reaction, and the reaction
Pyrolysis gas and undecomposed residue and fluidized medium generated by
Component that separates the char mixture consisting of
A solution, Undecomposed residue and flow taken out from the thermal decomposition means
Do not allow the char mixture of media to flow with air.
Char burning means for burning the undecomposed residue Approximately 400 using the combustion heat energy of the pyrolysis gas
One or more first for producing hot water or steam below ℃
Steam production means, The heat energy obtained by the char combustion means
The hot water or steam produced by the first steam production means
Including one or more second steam producing means for producing hot steam, Between the pyrolysis means and the first steam producing means, a front
By the primary combustion heat of the pyrolysis gas, the char combustion means
Separated from each gas taken out by thermal decomposition means
An ash melting and separating means for melting and separating the ash thus separated is provided,
The pyrolysis gas is sent to the ash melting and separating means to melt the ash.
Together with melting Combustion gas of pyrolysis gas burned by the ash melting and separating means
And the moisture gas obtained by the drying means from the first vapor of the one
Utilizes the heat of incineration of waste, which is characterized by being introduced into manufacturing means.
Used superheated steam production equipment. 3. The drying means and / or the thermal decomposition means
However, it is discarded by using the high temperature sand obtained from the char combustion means.
Either a fluidized bed, kiln, or horizontal stirring tank for drying things
The superheated steam manufacturing apparatus utilizing the heat of incineration of waste according to claim 2, wherein