JP3276273B2 - Superheated steam production equipment 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 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 solid waste contains a chlorine-containing organic compound such as PVC plastic, and the flammable component has a C1 content of about 0.2 to 0.1%.
Contains 5%. Chlorine contained in PVC plastic and the like mixed into waste such as municipal waste becomes HC1 by combustion (usually, HC1 contained in flue gas from municipal waste combustion).
(1 is about 500 to 1000 ppm), which acts on the tube of the steam generation 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 using fuel such as heavy oil or LNG containing almost no chlorine as fuel, which is remarkably lower than the power generation efficiency of a plant capable of setting the boiler tube temperature to 500 to 600 ° C. of about 40%, and its improvement has been strongly desired. .

[0004] In view of such technical problems, the present inventors have filed an earlier application (Application No .: Japanese Patent Application No. 6-324843).
, In a fluidized bed as the incinerator, at a temperature of 300 to 700 ° C.
It has been found that a char mixture consisting of the uncracked residue from the fluidized bed and the fluidized medium results in a substantially chlorine-free uncracked residue. That is, it was found that substantially all chlorine contained in the waste was contained in the pyrolysis gas and was discharged to the pyrolysis gas outlet line.

[0005] Based on such knowledge, the incinerator side supplies waste into a space having a temperature of 300 ° C or higher to cause a pyrolysis reaction, and generates a pyrolysis gas generated by the reaction, undecomposed residues and A first fluidized bed (hereinafter referred to as a pyrolysis means) for separating a char mixture composed of a fluidized medium and an incombustible substance from each other, and a method for completely burning the undecomposed residue while blowing the char mixture upward by air or combustion exhaust gas. 2 fluidized beds (hereinafter referred to as char combustion means), while the first and second boilers are connected in series on the boiler side, and the heat of the pyrolysis gas is utilized in the lower stage boiler. About 400 ° C or less, specifically 30
Hot water or steam at about 0 ° C. is produced (hereinafter referred to as first steam producing means), and then the hot water or steam at about 300 ° C. is introduced into a second boiler to obtain combustion gas obtained from the char burning means. Has been proposed to produce superheated steam of about 500 ° C. or higher by the heat of the superheated steam (hereinafter referred to as second steam production means).

The present invention further develops such prior art and provides 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 the boiler tube due to chlorine. To do. Another object of the present invention is to efficiently perform the char combustion in the char combustion means and the pyrolysis in the pyrolysis means, and to more efficiently reduce chlorine and obtain superheated steam at a high temperature as compared with the prior art. It is an object of the present invention to provide a superheated steam that can be produced.

[0007]

According to the first and second aspects of the present invention, a temperature of 300.degree. C. or more, preferably 300 to 70.degree.
A waste material is supplied into a space at 0 ° C. to cause a pyrolysis reaction, and a pyrolysis gas generated by the reaction, a char mixture comprising an undecomposed residue and a fluid medium, and an incombustible material are separated from each other, for example, a fluidized bed. A pyrolysis means, a char combustion means such as a fluidized bed or a pyrolysis furnace for completely burning the undecomposed residue while blowing the char mixture upward by air or combustion exhaust gas, and ash melting the pyrolysis gas.
Air or oxygen-enriched air in the ash melting furnace.
Gas is introduced together with the pyrolysis gas to produce a heat of combustion of the pyrolysis gas.
Ash melting means for melting the ash component, and recombusting the pyrolysis gas directly or after passing through the ash melting means , and utilizing the heat, preferably about 400 ° C. or less, specifically about 30 ° C.
First steam producing means for producing hot water or steam at a temperature of 0 to 350 ° C. or lower; and superheated steam produced by the first steam producing means by the heat of the combustion gas obtained by the char burning means. A second steam producing means, wherein a char backflow preventing means is arranged in a char passage connecting between the pyrolysis means and the char burning means.

[0008] Such a backflow preventing means is provided, for example, by setting the interface of the char mixture to the pyrolysis means side larger than that of the char combustion means side as shown in FIG. It may be constituted by a pressure difference forming means such as a seal pot having a preventing function, and the backflow preventing means is forcibly moved from the pyrolysis means side to the char combustion means side as shown in FIG. Alternatively, the mechanical transfer means may be configured to transfer the char, and preferably to be inclined upward from the inlet side to the outlet side of the mechanical transfer means so as to have a gravity difference.

According to the invention, the char mixture separated by the thermal decomposition means contains substantially no chlorine in any of the above claims, and is used as a superheat source of the second steam production means. Even if it is configured to obtain superheated steam of not less than ° C, high-temperature corrosion of equipment does not occur.

A pyrolysis gas containing chlorine is used as a heating source of the first steam producing means.
Since it is intended to manufacture hot water or steam at a temperature of 0 ° C. or less, specifically, about 300 to 350 ° C. or less, only a temperature lower than a high temperature corrosion temperature is heated. Absent.

As described above, in the char combustion means, it is necessary to increase the height of the fluidized bed in order to enable complete combustion, so that the pressure in the combustion means increases, and thus the fluid medium And the like may flow backward from the combustion means side to the thermal decomposition means side. Therefore, in the char passage connecting the pyrolysis means and the char combustion means, a char backflow prevention means 50 is arranged,
The char combustion in the char combustion means and the pyrolysis in the pyrolysis means are efficiently performed.

The backflow preventing means is configured such that the pressure on the pyrolysis means side is P ₂ and the pressure on the char combustion means side is P ₂ by a pressure difference forming means such as a seal pot as shown in FIG. _When it is set to ₁ , ΔH · ρ> P ₁ −
As will become P ₂ (ΔH · ρ: the difference in pressure of the pressure and char combustion means side of the pyrolysis furnace side) may be formed.

As shown in FIG. 3, when the backflow prevention means is constituted by the mechanical transport means, the mechanical transport means is inclined upward from the inlet side to the outlet side so as to have a gravity difference. It is preferable to arrange and configure, so that the inside of the mechanical conveying means is compacted by the flowing medium, and the gas sealing effect in the flowing medium is increased. In addition, although the quantitative property is increased by using the mechanical transfer means, the seal pot is excellent in cost and abrasion resistance.

In the third aspect of the present invention, the first
Alternatively, the steam heated by the second steam manufacturing means or a portion of the hot water or steam introduced into any of the manufacturing means may be appropriately introduced into the heat exchange means arranged on the high temperature side of the combustion means. It is a feature. That is, since the combustion means decomposes the undecomposed residue while blowing the char mixture upward by air or combustion exhaust gas, the combustion gas contains a high-temperature fluid medium.
Therefore, in the present invention, utilizing the high-temperature fluid medium, a heat exchange means is arranged on the high-temperature side of the char combustion means, and the steam or the steam heated by the first or second steam production means is used. By performing heat exchange with a part of the hot water or steam introduced into any of the above-mentioned production means, the following operation can be performed.

That is, hot water introduced into the first steam producing means is introduced into the heat exchanging means to raise the temperature to a certain extent, whereby heat exchanging means-first steam producing means-second steam producing means
The temperature can be raised in three stages substantially in series with the steam production means of the above, and a large amount of sufficiently heated superheated steam can be obtained. Further, the amount of heating of the second steam producing means is increased by introducing the hot water or steam introduced into the second steam producing means together with the first steam producing means into the heat exchange means in parallel. And a large amount of superheated steam can be obtained.

The provision of the heat exchange means on the high temperature side of the char combustion means is unnecessarily high, around 800 to 1300 ° C., and if it flows directly to the outlet line, it does not have the temperature in the ordinary metal line. However, by dropping the temperature to 800 to 950 ° C., a normal heat-resistant metal line can be used. Further, even if the temperature is lowered to 800 to 950 ° C. as described above, the steam temperature in the second steam producing means is set to 500 to 600 ° C.
There is no hindrance in maintaining it.

According to a fourth aspect of the present invention, there is provided a separator connected to an outlet side of the combustion means for separating the combustion gas and the fluid medium from the combustion means. The heated steam or a part of the hot water or steam introduced into any one of the production means is appropriately introduced to the fluid medium outlet side of the separation means, and heated by thermal contact with the fluid medium. Is what you do.
According to this invention, since the separation means for separating the combustion gas and the fluid medium is provided on the outlet side of the char combustion means, in other words, the high temperature fluid medium of about 800 to 950 ° C. is used as the thermal decomposition means. By returning each of the char combustion means, formation of a fluidized bed at a desired temperature and temperature control become easy.

In the present invention, a heat exchange means is arranged on the fluid medium outlet side of the separation means, and is introduced into the steam heated by the first or second steam production means or any one of the production means. By heating a portion of the hot water or steam by appropriate thermal contact with the fluid medium, the same effect as the invention of claim 3 can be achieved. In this case, heat exchange means (hereinafter referred to as first heat exchange means) is disposed on the high temperature side of the char combustion means, and heat exchange means (hereinafter referred to as second heat exchange means) is disposed also on the fluid medium outlet side of the separation means. You may. Further, by arranging the first heat exchanging means, the first steam producing means, the second steam producing means, and the second heat exchanging means, it is possible to substantially increase the temperature in four stages in series. High and sufficiently heated superheated steam can be obtained.

Further, as shown in the embodiment described later, the first heat exchange means and the first steam production means are arranged in parallel, the second steam production means and the second heat exchange means are arranged in series. Accordingly, the temperature can be raised substantially in three stages of parallel / series, and a large amount and sufficiently heated superheated steam can be obtained. Either the first heat exchange means or the second heat exchange means may be selectively used. It is preferable to use a superheater or a boiler as the heat exchange means.

[0020]

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.
1 shows an apparatus for producing superheated steam using the heat of incineration of wastes according to an embodiment of the present invention. In the drawing, reference numeral 1 denotes a pyrolysis furnace comprising a fluidized bed, wherein fluidized sand or the like is dispersed on a dispersion plate 3 such as a perforated plate. Fluid medium and waste such as municipal solid waste are supplied from a waste supply line 4 and a sand circulation line 5, and the temperature is controlled by air or flue gas supplied from air or flue gas inlet line 6. A fluidized bed space of 300 ° C. or higher is generated to cause a pyrolysis reaction of the waste, and the pyrolysis gas generated by the reaction is supplied to a pyrolysis gas outlet line 7. From the char mixture removal line 9 via the backflow prevention means 50,
The incombustibles are separated from each other and taken out from the incombustibles take-out line 8. The air or the flue gas supplied to the pyrolysis furnace 1 from the air or flue gas inlet line 6 contains a small amount of oxygen (about 5%) in order to efficiently perform pyrolysis in the range of 300 to 700 ° C. The temperature is 100-3
It is preferable to use the combustion exhaust gas maintaining the temperature of 00 ° C., specifically, the combustion exhaust gas taken out from the outlet line 25 of the first boiler 24.

The pyrolysis gas extracted from the pyrolysis gas outlet line 7 is supplied to the ash melting furnace 31 and the pyrolysis gas combustion furnace 34.
And is introduced into the first boiler 24. That is, the ash melting furnace 31 introduces air or oxygen-enriched air together with the pyrolysis gas into the melting furnace 31 while swirling and separating the sand-mixed pyrolysis gas ash by a swirling flow. The ash is melted at 1300 ° C. by the heat of combustion, and the melted ash is melted through a molten ash outlet line 32 into a water storage section 32A.
To produce a water-cooled slag of about several mm, which is used as building aggregate.

In the ash melting furnace 31, ash separated from a high-temperature filter 40 provided in a gas outlet line 17 to be described later is mixed with a dust line 29 and a sand outlet line 1 of a cyclone.
The ash separated from the ash separator 41 (screen) provided at 8 is respectively introduced through the dust line 29a, and these are also melted and separated. Then, the pyrolysis gas from which the ash has been removed is introduced into the pyrolysis gas combustion furnace through the outlet line 33,
Complete combustion is performed by the air supplied from the air supply line, and the first boiler 24 is
To be introduced.

A part of the pyrolysis gas obtained by the pyrolysis furnace 1 is supplied to a branch line 7a on the upstream side of the ash melting furnace 31.
In other words, high-temperature flammable gas of 350 ° C. to 400 ° C. can be circulated and supplied to the thermal decomposition furnace 1 because the gas is supplied to the inlet side below the dispersion plate 3 of the thermal decomposition furnace 1 through Therefore, the pyrolysis gas is N ₂ , C in air or flue gas.
Minimizing dilution with an inert gas such as O ₂ , H ₂ O,
The calorific value per unit volume can be increased, and the combustion temperature required for ash melting can be easily increased to 1300 ° C.
Stable thermal decomposition becomes possible by suppressing temperature fluctuation.

FIG. 2 shows the char mixture removal line 9.
Shows one embodiment of the backflow prevention means 50 disposed above,
By setting the char pressure to the pyrolysis furnace 1 side higher than the pressure to the char combustion furnace 10 side, a seal pot 59 having a backflow prevention function is formed. That is, the pyrolysis furnace 1
The char mixture which has overflowed from the partition wall 55 flows into the backflow prevention means 50, and the backflow prevention means 50 folds the char mixture take-out line 9 up and down through the partition wall 52 and communicates with the pyrolysis furnace 1 side. Fluidized bed passage 5
0a and a second fluidized bed passage 50b communicating with the char combustion furnace 10 side are formed adjacent to each other, and a seal pot 59 (a folded portion of the two passages,
And a dispersing plate 53 is disposed at the bottom of the seal pot 59, and the air introducing space below the dispersing plate is divided into two left and right introducing spaces 54a by the partition plate 51. , 54b, so that air or exhaust gas having independent flow rates can be introduced into the first and second fluidized bed passages 50a, 50b through a line 58.

The first and second fluidized bed passages 50
The passage heights of a and 50b are determined by setting the pressure on the pyrolysis furnace 1 side to P
_2, the pressure of the char combustion furnace 10 side when the _{P 1, ΔH · ρ> P} 1 -P 2 ΔH :( first fluidized bed passages 50a height H ₁ - second fluidized bed passage 50b height H ₂ ) ρ: fluidized bed density (specific gravity) should be satisfied, and if the flow rates of the introduction spaces 54a, b divided into two left and right introduction spaces 54a, b by the partition plate 51 are different. By increasing the flow velocity of the second fluidized bed passages 50a and 50b on the side of the char combustion furnace 10 and decreasing the flow velocity of the first fluidized bed passage 50a on the pyrolysis furnace 1 side, the backflow prevention effect is further enhanced.

Further, as shown in FIG.
0B may constitute the backflow prevention means 50. For example, a screw feeder 61 is provided in the middle of the char mixture take-out line 9 or at the char mixture inlet side of the char combustion path, and the screw feeder is inclined upward from the inlet side to the outlet side to have a gravity difference. It is arranged and configured. As a result, the inside of the mechanical transfer means 50B is compacted by the fluidized sand, and the gas sealing effect with the fluidized sand is increased.

Reference numeral 10 denotes a char combustion furnace consisting of a tower type fluidized bed furnace. The char mixture supplied from a char mixture take-out line 9 through a backflow prevention means 50 onto a dispersion plate 11 disposed at the bottom, and a sand circulation line. The fluid sand circulated from 19 is stored.

Air is further supplied from the air supply line 12 below the dispersion plate 11 to the air supply line 13 in the middle region of the char combustion furnace 10 to burn undecomposed residues, and the combustion gas at about 1500 ° C. A water-cooled wall boiler or a superheat is disposed in the upper region of the char combustion furnace 10 through a line 26 ', and 950 to 1300
Combustion gas that has risen unnecessarily to around 800 ° C
And a part of the boiler water supplied to the first boiler is heated. The heating temperature of the boiler water is about 300 ° C. As described above, even if the combustion gas temperature is lowered to 800 to 950 ° C., the steam temperature in the second
There is no problem in maintaining the temperature at -600 ° C.

Small incombustibles that are not burned in the combustion furnace in the combustion furnace are taken out from the incombustibles take-out line 14. Then, the combustion gas of the sand mixture, which has been heated as described above, is introduced into a gas / solid separation device, for example, a cyclone 16 through a sand / combustion gas outlet line 15, where the combustion gas is separated from the flowing sand. Second from gas outlet line 17
It is introduced into the boiler 20.

The fluidized sand taken out from the sand outlet line 18 is separated into ash by an ash separator 41 (screen), and then is discharged from the outlet line 18A via a distribution regulating valve comprising a straightening plate and a rotary valve to a sand circulation line. From 19, combustion furnace 10
Is supplied to the pyrolysis furnace 1 from the sand circulation line 5.

The ash separated by the ash separator 41 (screen) is introduced into the ash melting furnace 31 through the dust lines 29a / 29. Further, the combustion furnace 10 and the second boiler 2
A heat exchanger 37 composed of a super heater and a high temperature filter 40 are arranged in series in the combustion gas line 17 between 0,
For example, the combustion gas heated to about 900 ° C.
7, the heat is exchanged with the superheated steam after heating in the second boiler 20, and the heating temperature is lowered to about 600 ° C.
0 is introduced. After the ash in the combustion gas is separated by the high-temperature filter 40, the second
It is introduced into the boiler 20.

The ash separated by the high temperature filter 40 is introduced into an ash melting furnace 31 through a dust line 29. Reference numeral 20 denotes a second boiler and reference numeral 24 denotes a first boiler. In the first boiler 24, the pyrolysis gas taken out from the pyrolysis gas outlet line 7 is reburned by the air taken in from the air inlet line 21 to produce a second boiler gas. The boiler water introduced into the first boiler 24 together with the combustion exhaust gas discharged from the outlet and taken in from the boiler water inlet 26 is heated to about 300 ° C., and steam is sent from the first boiler steam outlet 27 to the second boiler 20. Supply.

In the second boiler 20, steam extracted from the first boiler steam outlet line 27 of the first boiler 24 and heated by the water-cooled wall boiler 36 are branched steam lines 27 '.
Through the combustion gas supplied through the combustion gas outlet line 17, and
A superheated steam of about 00 to 600 ° C. is produced and taken out from the second boiler steam outlet 28.

Next, the operation of the above embodiment will be described in detail.
Chlorine-containing organic compounds such as PVC plastics are mixed in the waste such as municipal waste supplied to the pyrolysis furnace 1, and the combustibles contain about 0.2 to 0.5% as C1. . Then, municipal solid waste from the waste supply line 4 and high-temperature circulating sand from the sand circulation line 5 are supplied to the pyrolysis furnace 1, respectively, and air or combustion exhaust gas is supplied from the lower air or combustion exhaust gas inlet line 6 to flow. By treating at a temperature of 300 to 700 ° C. in the fluidized bed in which the sand 2 is fluidized, an undecomposed residue substantially free of chlorine is obtained from the char mixture removal line 9. That is, substantially all of the chlorine contained in the waste is contained in the pyrolysis gas and discharged to the pyrolysis gas outlet line 7. The large-sized incombustibles separated by the thermal decomposition reaction in the thermal decomposition furnace 1 are taken out of the furnace through an incombustibles take-out line 8.

The pyrolysis gas extracted from the pyrolysis outlet line 7 of the pyrolysis furnace 1 includes low calorie gas, oil,
Tar and HC1, which are completely burned in the ash melting furnace 31 and the pyrolysis combustion furnace, and then together with the combustion exhaust gas from the second boiler gas outlet line 22 from the first boiler gas inlet 23 to the first boiler 24. Supply.

Accordingly, it is possible to stably produce steam over a long period of time without incorporation of ash or the like into the pyrolysis gas introduced into the first boiler 24.
The temperature of the pyrolysis gas introduced into 4 is approximately 850-900 ° C
(Up to around 950 ° C.), a large amount of steam at around 300 ° C. produced by the boiler 24 can be produced.

The gas at the first boiler gas inlet 23 is HC1
Is contained at about 500 to 1000 ppm, so that the flow rate of the boiler water is adjusted to keep the tube surface temperature of the first boiler 24 at about 350 ° C. or less, which is the same as the conventional one, thereby suppressing high-temperature corrosion. For this reason, high-temperature superheated steam cannot be obtained in the first boiler 24, but can be heated up to about 300 ° C., and if this is further heated in the second boiler 20, about 500 to 600 ° C.
High temperature superheated steam can be obtained.

The char mixture taken out of the char mixture take-out line 9 in the pyrolysis furnace 1 is composed of fluidized sand and uncracked residue, and is substantially free of chlorine.
In the combustion furnace 10, the air is supplied to the lower part of the combustion furnace 10 via the backflow prevention means 50, and is burned by air supplied from the air supply line 12 through the distribution plate 11.

In the char combustion furnace 10, it is necessary to increase the height of the fluidized bed in order to enable high-temperature combustion. Therefore, the pressure in the char combustion furnace 10 increases, and the There is a possibility that sand or the like may flow backward from the combustion furnace 10 to the pyrolysis furnace 1. In the present invention, however, the backflow prevention of the char mixture is performed in the char mixture take-out line 9 connecting the pyrolysis furnace 1 and the char combustion furnace 10. Means 50 are disposed to prevent backflow from the char combustion furnace 10 and to efficiently perform char combustion and pyrolysis in the pyrolysis furnace 1.

In this case, the amount of air supplied from the air supply line 12 is adjusted, and the undecomposed residue is burned while blowing the fluidized sand upward. Further air may be supplied from the air supply line 13 for complete combustion. Combustion furnace 1
The temperature of 0 rises due to the exothermic combustion reaction. This temperature value is determined by the calorific value of the undecomposed residue supplied from the char mixture removal line 9, the amount of air in the air supply lines 12, 13 and the amount and temperature of the sand in the sand circulation line 19,
The temperature may be as high as about 950 to 1300 ° C. Then, heat exchange with the boiler water introduced from the branch pipe 26 is performed by the water-cooled wall boiler 36, so that the sand mixed combustion gas 800 to
It is easy to reach 950 ° C. Incombustibles that have been miniaturized by melting glass and cans, etc.
Pull out from 4.

The combustion gas generated in the combustion furnace 10 at a high temperature of 800 to 950 ° C. and substantially containing no chlorine passes through the sand / combustion gas outlet line 15 together with the sand and the cyclone 16.
The fluidized sand is taken out from the sand outlet line 18 and the exhaust gas is taken out separately from the gas outlet line 17. And 800-taken out from the sand exit line 18
After the ash content of the 950 ° C. high-temperature fluidized sand is separated by the ash separator 41, a part of the ash is returned to the pyrolysis furnace 1 through the sand circulation line 5, and the temperature inside the pyrolysis furnace 1 is maintained at a predetermined temperature. Used to The remainder is returned to the combustion furnace 10 via the sand circulation line 19.

Therefore, according to the present embodiment, the cyclone 1
6. Since the ash separator 41 for separating the ash from the fluidized sand is provided on the side of the sand outlet line 18 of 6, the ash and the like are mixed in the fluid medium returning to the pyrolysis furnace 1 and the char combustion furnace 10, respectively. And stable pyrolysis and char combustion can be achieved over a long period of time. On the other hand, the ash is separated from the ash melt separator 31 described above.
By introducing the molten ash, it becomes possible to produce aggregates and the like by using the molten ash, and since the ash is high in temperature, the separated pyrolysis gas is reheated by utilizing its heat. Is also possible.

On the other hand, the 800-950 ° C. high-temperature combustion gas taken out from the gas outlet line 17 of the cyclone 16 is pre-cooled by the heat exchanger 37, introduced into the high-temperature filter 40, and In order to separate ash therein, it is possible to stably produce steam over a long period of time without mixing ash or the like into the combustion gas introduced into the second boiler 20, and to perform the above combustion. Since the unburned chlorine compounds in the gas are burned, so-called dioxin can be reliably removed.

Then, a heat exchanger 37 is arranged on the inlet side of the high-temperature filter 40, and the superheated steam heated from the second boiler 20 is introduced into the heat exchanger 37, and
By pre-cooling the combustion gas introduced to zero, the load applied to the high temperature filter 40 can be significantly reduced. Further, by introducing the superheated steam heated by the second boiler 20 into the heat exchanger 37, it is possible to obtain a superheated steam which is further heated. In particular, the second boiler 20 includes the first boiler 24 and the water-cooled wall boiler. Although the superheat capacity may be insufficient due to the introduction of the steam of 36, the present embodiment also solves the heat capacity shortage by introducing the superheated steam heated by the second boiler 20 into the heat exchanger 37. Thus, it is possible to obtain a sufficiently heated superheated steam.

Further, the ash separated by the high temperature filter 40 and the ash separator 41 is introduced into the ash melting / separating furnace 31, so that the molten ash can be used to produce aggregates and the like. Since the ash content is high in temperature, it is possible to reheat the separated pyrolysis gas by using the heat.

The steam introduced into the second boiler 20 by the second boiler 20 is used to further heat the steam produced by the first boiler 24 to become superheated steam. Since the exhaust gas coming through the gas outlet line 17 does not substantially contain chlorine,
Even when the surface temperature of the boiler tube of the second boiler 20 is set to 350 ° C. or more, high-temperature corrosion is greatly reduced. Therefore, the steam temperature in the tube is about 500-600 ° C, 100Kg
f / cm ² and the second boiler steam outlet 28
, Stable high-temperature superheated steam is obtained.

In order to maintain the temperature of the pyrolysis furnace 1 at a predetermined temperature of 300 ° C. or higher in the pyrolysis furnace 1, the amount of oxygen in the air or the flowing gas supplied from the flue gas inlet line 6 is adjusted, in other words, A large amount of exhaust gas from one boiler 24 is supplied and a sand outlet line 18 from the cyclone 16
It is preferable that a part of the sand having a high temperature of about 800 to 950 ° C. taken out from the sand is supplied from the sand circulation line 5 to be used as a heat source. For this purpose, in the combustion furnace 10 of the combustion furnace 10, the empty space velocity of the gas (gas flow rate in the furnace / cross-sectional area of the furnace) is 3 to 6 m / s.
As a result, the undecomposed residue is burned while blowing off the sand supplied from the char mixture take-out line 9, and the sand is separated from the combustion gas by the cyclone 16 and the pyrolysis furnace 1 and the combustion furnace 10 are separated.
A high-speed circulating fluidized bed is suitable for circulating feed.

In order to carry out the present invention more efficiently, the amount of the substantially chlorine-free char mixture taken out from the char mixture take-out line 9 is made as large as possible, preferably 40% or more of the combustible material in the raw material, Combustion furnace 1
It is desirable to increase the amount of heat generated at 0 and increase the amount of heat recovered in the second boiler 20. As a result, the power generation efficiency can be 30% or more. Therefore, in the present embodiment, the temperature of the pyrolysis furnace 1 is set at 300 to 700 ° C., preferably 350 to 450 ° C., as conditions under which the chlorine in the refuse can be substantially separated and removed and the char recovery rate can be 40% or more. It is desirable to do.

[0049]

As described above, according to the present invention, it is possible to prevent high temperature corrosion of a boiler tube by chlorine while preventing high temperature corrosion.
High-pressure superheated steam can be obtained efficiently. Further, according to the present invention, it is possible to more efficiently perform pyrolysis and char combustion and obtain a high-temperature superheated steam, as compared with the prior art. And so on.

[Brief description of the drawings]

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

FIG. 2 is a schematic diagram in which the backflow prevention means shown in FIG. 1 is constituted by a pressure difference forming means having a backflow prevention function.

FIG. 3 is a schematic diagram in which the backflow prevention means shown in FIG. 1 is constituted by mechanical transport means for forcibly transporting char from the pyrolysis means side to the char combustion means side.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Pyrolysis furnace (pyrolysis means) 2 Fluid medium such as sand 10 Combustion furnace (char combustion means) 11 Dispersion plate 16 Cyclone (separation means) 20 Second boiler (second steam production means) 24 First boiler (first 1 steam production means) 31 ash melting furnace 34 pyrolysis gas combustion furnace 36 water-cooled wall boiler (heat exchange means arranged on the high temperature side of char combustion means) 37 heat exchanger 40 high temperature filter 50, 50A, 50B backflow prevention means 50a first fluidized bed passage 50b second fluidized bed passage 59 seal pot 61 screw feeder

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI F23C 10/20 F23G 5/16 ZABE F23G 5/00 115 5/30 ZABE ZAB ZABK 5/16 ZAB ZABM 5/30 ZAB 5/32 ZAB 5/46 ZABA ZABB 5/32 ZAB 7/00 103A 5/46 ZAB ZAB F23J 1/00 ZABB 7/00 103 F23C 11/02 ZAB ZAB 312 F23J 1/00 ZAB 313 (72) Inventor Yuji Kaihara Yokohama 12 Nishiki-cho, Naka-ku Mitsubishi Heavy Industries, Ltd. Yokohama Works (72) Inventor Tetsuo Sato 12 Nishiki-cho, Naka-ku, Yokohama-shi Mitsubishi Heavy Industries, Ltd. Yokohama Works (56) References JP-A-5-346204 (JP, A) JP-A-58-95104 (JP, A) JP-A-51-36201 (JP, A) JP-A-1-252806 (JP, A) JP-A-7-35322 (JP, A) JP-A-5-141636 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23G 5/027 F22B 1/18 F22G 1 / 16 F23C 10/00 F23C 10/18 F23C 10/20 F23G 5/00 F23G 5/16 F23G 5/30 F23G 5/32 F23G 5/46 F23G 7/00 F23J 1/00

Claims (4)

(57) [Claims] (1) providing waste in a space having a temperature of 300 ° C. or more;
To cause the thermal decomposition reaction, which is generated by the reaction
Char consisting of pyrolysis gas, uncracked residue and flowing medium
Pyrolysis means for separating the mixture and the incombustible material from each other; and raising the char mixture by air or flue gas
To completely burn the undecomposed residue while blowing it away
Combustion means,The pyrolysis gas is introduced into an ash melting furnace, and the inside of the ash melting furnace is emptied.
Gas or oxygen-enriched air with the pyrolysis gas
Melting means for melting ash by the heat of combustion of the pyrolysis gas
When,  The pyrolysis gas directly orReburn after passing through ash melting means
Let meUsing the heat, hot water of about 400 ° C or less or
First steam producing means for producing steam, and heat of the combustion gas obtained by the char burning means
Hot water or steam produced by the first steam producing means
A second steam producing means for producing superheated steam, and a char flow connecting the pyrolysis means and the char burning means.
Provide backflow prevention means on the road.And the reverse
Flow preventing means, the interface of the char mixture on the pyrolysis means side
Set larger than the char-mixture interface on the char combustion means side
Pressure difference forming hand with gas backflow prevention function
Composed of stepsUtilizes waste heat of incineration
Superheated steam production equipment. (2)Provide waste in a space with a temperature of 300 ° C or higher.
To cause the thermal decomposition reaction, which is generated by the reaction
Char consisting of pyrolysis gas, uncracked residue and flowing medium
Pyrolysis means for separating the mixture and incombustibles from each other, Up the char mixture by air or flue gas
To completely burn the undecomposed residue while blowing it away
Combustion means, The pyrolysis gas is introduced into an ash melting furnace, and the inside of the ash melting furnace is emptied.
Gas or oxygen-enriched air with the pyrolysis gas
Melting means for melting ash by the heat of combustion of the pyrolysis gas
When,  The pyrolysis gasAfter passing through the ash melting meansLet it reburn,That
Using heatAbout 400 ° C or lessProduce hot water or steam
First steam producing means, By the heat of the combustion gas obtained by the char combustion means
The first steam maker Hot water or steam produced in the stage
Second steam producing means for producing superheated steam, Char flow connecting the pyrolysis means and the char combustion means.
In the road, while installing a means for preventing backflow of char, The reverse
The flow prevention means is closer to the char combustion means than the pyrolysis means.
Composed of mechanical transport means for forcibly transporting char
And upward from the inlet side of the mechanical transport means toward the outlet side.
It is characterized by being tilted and placed with a difference in gravity
Superheated steam production equipment that uses the heat of incineration of waste. 3. The steam heated by the first or second steam producing means or a portion of hot water or steam introduced into any one of the producing means is disposed on a high temperature side of the char combustion means. 3. A superheated steam production apparatus utilizing waste incineration heat according to claim 1 or 2, wherein the apparatus is introduced into the heat exchange means as appropriate. 4. A steam connected to an outlet side of the char combustion means and separating the combustion gas and the fluid medium from the char combustion means, wherein the steam heated by the first or second steam production means is provided. Alternatively, a part of the hot water or steam introduced into any one of the production means is appropriately introduced to the fluid medium outlet side of the separation means, and heated by thermal contact with the fluid medium. Or a superheated steam production apparatus utilizing the heat of incineration of the waste according to 2 .