U.S. patent application number 09/781439 was filed with the patent office on 2001-10-25 for waste processing system and fuel reformer used in the waste processing system.
This patent application is currently assigned to Hitachi, Ltd.. Invention is credited to Ajiro, Taiko, Hatamiya, Shigeo, Ishigaki, Yukio, Koyama, Kazuhito, Okusawa, Tsutomu, Sunou, Megumi, Tokunaga, Kenji, Yamagishi, Masahiko.
Application Number | 20010032451 09/781439 |
Document ID | / |
Family ID | 25501580 |
Filed Date | 2001-10-25 |
United States Patent
Application |
20010032451 |
Kind Code |
A1 |
Okusawa, Tsutomu ; et
al. |
October 25, 2001 |
Waste processing system and fuel reformer used in the waste
processing system
Abstract
A waste-to-energy incineration system, in which the amount and
the heat value of exhaust gas largely changes in a long and a short
periods, comprises an incinerator for burning waste, a boiler in
the incinerator for generating steam with exhaust heat generated by
the incinerator, a superheater for superheating steam generated in
the boiler, a steam turbine driven by steam superheated by the
superheater, a generator driven by the steam turbine, a fuel
reformer for reforming source fuel, and a combustor burning fuel
gas reformed by the fuel reformer and at least a part of exhaust
gas led from the incinerator which are able to stably decompose
generated dioxin, whereby it becomes possible to stably and almost
completely decompose dioxin in waste incineration exhaust gas.
Inventors: |
Okusawa, Tsutomu;
(Hitachi-shi, JP) ; Koyama, Kazuhito;
(Hitachi-shi, JP) ; Yamagishi, Masahiko;
(Hitachi-shi, JP) ; Hatamiya, Shigeo;
(Hitachi-shi, JP) ; Ajiro, Taiko; (Hitachi-shi,
JP) ; Sunou, Megumi; (Naka-gun, JP) ;
Ishigaki, Yukio; (Hitachi-shi, JP) ; Tokunaga,
Kenji; (Tokyo, JP) |
Correspondence
Address: |
MATTINGLY, STANGER & MALUR
104 East Hume Avenue
Alexandria
VA
22301
US
|
Assignee: |
Hitachi, Ltd.
|
Family ID: |
25501580 |
Appl. No.: |
09/781439 |
Filed: |
February 13, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09781439 |
Feb 13, 2001 |
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09343273 |
Jun 30, 1999 |
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6282902 |
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09343273 |
Jun 30, 1999 |
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08959026 |
Oct 28, 1997 |
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6014863 |
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Current U.S.
Class: |
60/39.6 ;
60/39.182 |
Current CPC
Class: |
F23G 5/0276 20130101;
F02G 2254/11 20130101; F23J 15/08 20130101; B01B 1/005 20130101;
Y02E 20/12 20130101; F23G 5/46 20130101; F23G 2202/106 20130101;
C01B 3/38 20130101; F23G 2206/10 20130101; F01K 3/247 20130101 |
Class at
Publication: |
60/39.6 ;
60/39.182 |
International
Class: |
F02G 001/00; F02G
003/00; F02C 006/00; F02C 005/00 |
Claims
What is claimed is:
1. A waste-to-energy incineration system, comprising: an
incinerator for burning waste; a boiler in said incinerator for
generating steam by using exhaust heat generated by said
incinerator; a superheater for superheating steam generated in said
boiler; a steam turbine driven by steam superheated by said
superheater; a generator driven by said steam turbine; a fuel
reformer for reforming fuel; and a combustor burning fuel gas which
is reformed by said fuel reformer, and at least a part of
incinerator exhaust gas.
2. A waste-to-energy incineration system, comprising: an
incinerator for burning waste; a boiler in said incinerator for
generating steam with exhaust heat generated in said incinerator; a
steam utilizer for utilizing steam generated in said boiler; a fuel
reformer for reforming fuel; wherein fuel gas reformed by said fuel
reformer is led to said incinerator.
3. A waste-to-energy incineration system, comprising: an
incinerator for burning waste; a boiler in said incinerator for
generating steam by using exhaust heat generated in said
incinerator; a steam utilizer for utilizing steam generated in said
boiler; another boiler different from said boiler; and a fuel
reformer for reforming fuel; a combustor for burning fuel gas which
is reformed by said reformer, and at least a part of incinerator
exhaust gas; wherein steam generated by said another boiler is led
to said fuel reformer.
4. A waste-to-energy incineration system, comprising: an
incinerator for burning waste; a boiler in said incinerator for
generating steam generated with exhaust heat generated in said
incinerator; a superheater for reheating steam generated in said
boiler; a steam turbine driven by steam led from said superheater;
a generator driven by said steam turbine; a fuel reformer for
partially oxidizing an amount more than 20% of source fuel; and a
combustor for burning fuel gas which is reformed by said fuel
reformer, and at least a part of incinerator exhaust gas.
5. A waste-to-energy incineration systems according to claim 1 or
clam 4, wherein steam extracted from a steam feed-water system
connecting said incinerator boiler with said steam turbine or the
steam utilizer is used as cooling medium injected in said fuel
reformer.
6. A waste-to-energy incineration systems according to one of claim
1 to clam 4, wherein a part of exhaust gas generated in said
incinerator is led to the fuel reformer as oxidizer together with
air or oxygen.
7. A waste-to-energy incineration systems according to one of claim
1 to clam 4, wherein at least a part of said exhaust gas generated
in said incinerator is led to said combustor as oxidizer together
with air or oxygen.
8. A waste-to-energy incineration systems according to clam 5,
wherein at a place of said steam feed-water system, a feed-water
evaporator utilizing combustion gas exhausted 25 from said
combustor as a heat source is provided, and steam superheated by
said feed-water evaporator is used as cooling medium injected in
said fuel reformer.
9. A waste incineration processing system, comprising: an
incinerator for burning waste; a boiler in said incinerator, for
generating steam with exhaust heat generated in said incinerator; a
steam utilizer utilizing steam generated in said boiler; and a fuel
reformer; wherein fuel reformed by said fuel reformer is injected
into said incinerator, and burned.
10. A waste incineration processing system, comprising: an
incinerator for burning waste; a boiler for generating steam; a
fuel reformer; and a combustor for burning fuel gas which is
reformed by said fuel reformer, and at least a part of incinerator
exhaust gas; wherein at least a part of steam generated in said
boiler is led into said fuel reformer.
11. A waste-to-energy incineration system according to one of claim
1-claim 8, wherein said fuel reformer includes a first chamber for
reforming fuel and a second chamber neighboring said first chamber,
at an outside of said first chamber, for leading steam as cooling
medium into said first chamber.
12. A waste-to-energy incineration system according to claim 11,
wherein in said first chamber, fuel gas is obtained by partially
oxidizing source fuel and said obtained fuel gas is reformed.
13. A waste-to-energy incineration system according to one of claim
1-claim 8, wherein said fuel reformer includes a fuel flowing
chamber in which fuel gas is obtained by partially oxidizing source
fuel and said obtained fuel gas is reformed, and a cooling jacket
arranged, neighboring said fuel flowing chamber, at an outside of
said fuel flowing chamber, for leading steam as cooling medium from
at least one place into said fuel flowing chamber; wherein the
amount more than 20% of said source fuel is partially oxidized in
said fuel flowing chamber.
14. A waste-to-energy incineration system according to claim 13,
wherein said fuel flowing chamber is composed of serial
sub-chambers having different sectional areas, respectively.
15. A waste-to-energy incineration system according to claim 13 or
claim 14, wherein said first chamber has a swirling means for
generating a swirling flow of said cooling medium.
16. A fuel reformer, comprising: a source fuel feeding means; a
cooling medium feeding means; a first chamber for generating fuel
gas by partially oxidizing source fuel fed by said source fuel
feeding means and reforming said fuel gas; and a second chamber
arranged, neighboring said first chamber, at an outside of said
first chamber, for leading cooling medium fed by said cooling
medium feeding means into said first chamber.
17. A fuel reformer, comprising: a source fuel feeding means; a
cooling medium feeding means; a fuel flowing chamber for generating
fuel gas by partially oxidizing source fuel fed by said source fuel
feeding means and reforming said fuel gas; and a cooling jacket
arranged, neighboring said fuel flowing chamber, at an outside of
said fuel flowing chamber, for leading steam as cooling medium fed
by said cooling medium feeding means from at least one place into
said fuel flowing chamber; wherein the amount more than 20% of
source fuel is partially oxidized in said fuel flowing chamber.
18. A fuel reformer according to claim 17, wherein said fuel
flowing chamber is composed of serial sub-chambers having different
sectional areas, respectively.
19. A fuel reformer according to one of claim 16-claim 18, wherein
said first chamber has a swirling means for generating a swirling
flow of said cooling medium.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a fuel reformer and a waste
processing system including reformer, especially to a direct heat
exchange type, catalystless fuel reformer, and a waste-to-energy
incineration system in which a direct heat exchange type,
catalystless fuel reformer is adopted.
[0003] 2. Description of Related Art
[0004] As a fuel reformer for reforming source fuel such as
hydrocarbon material to gas containing hydrogen, an indirect heat
exchange type fuel reformer or a direct heat exchange type reformer
has been largely used. Further, there are two types of fuel
reformer, that is, a fuel reformer using catalyst and a fuel
reformer without using catalyst.
[0005] In an indirect heat exchange type fuel reformer, a reaction
tube and a burner are provided. While the reaction tube is heated
by the combustion gas from the burner, raw gas enters the reaction
tune at an end of the reaction tube. Further, the raw gas is
partially oxidized (so-called partial combustion), and reformed to
gas including hydrogen, either by using catalyst or by using
coolant steam on a basis of hydrothermal reaction.
[0006] On the other hand, in an direct heat exchange type fuel
reformer, the heat required for reforming raw fuel is directly
given to raw fuel flowing in a fuel flowing path by partial
oxidization, which results in a high temperature gas of raw fuel.
The high temperature raw fuel (hereafter, referred as fuel for
simplicity) is reformed to gas including hydrogen, either by using
catalyst or by using steam coolant on a basis of hydrothermal
reaction. In a chemical industrial plant, a direct heat exchange
type reformer is mainly used.
[0007] In the method of using catalyst, since the catalyst can
lower the reforming energy, that is, the reforming temperature to
about 700.degree. C., only 20% of the fuel is consumed for partial
oxidization.
[0008] In the method of using no catalyst, due to absence of
catalytic energy saving effect, more than 20% of the fuel is
required for partial oxidization in order to obtain the reforming
energy, that is, the reforming temperature as high as 1300.degree.
C.
[0009] One of features of the waste-to-energy incineration system
is that the generated heat changes due to changes of the amount of
waste to be processed, depending on the day, the season or the
year, which is particular to the waste processing. Further, since
the waste processing is requested to be performed without stopping
of operations, in addition to the above-mentioned feature, the
maintenance-free composition or structure is strongly required for
the waste-to-energy incineration system. For satisfying the
above-mentioned requirement, each apparatuses composing the system
should be composed of long-service parts. To realize the
above-mentioned apparatuses, the method in which catalyst is not
used, is advantageous. However, in this method, it is indispensable
to produce energy necessary for reforming fuel gas by partially
oxidizing more than 20% of fuel in order to reform fuel gas with
the partial oxidation heat itself of fuel gas. (Hereafter, a fuel
reformer mainly indicates a fuel reformer without catalyst, in
which more than 20% of fuel is partially oxidized.)
[0010] An existing fuel reformer has been usually used, for
example, to a gas turbine power generation system. Further, an
power generation system in which an fuel reformer is provided, is
disclosed in JP-A-286835/1990, JP-A-332166/1993 and
JP-A-332167/1993.
[0011] Since the previously-mentioned indirect heat exchange type
fuel reformer include a burner for heating a reaction tube, such a
fuel reformer has a problem in that the size of the apparatus
becomes large, and an external heat source has to be provided.
[0012] On the other hand, a direct heat exchange type fuel reformer
is superior to an indirect heat exchange type fuel reformer in the
point that fuel itself produces heat source for reforming fuel gas
by partially oxidizing fuel. In addition, due to absence of a
burner and a reaction tube, the size of the fuel reformer can be
reduced in comparison with the indirect heat exchange type.
[0013] One of objects of the waste-to-energy incineration system is
to burn waste and decrease the volume of waste, without polluting
the environment, another objects is to generate power by utilizing
the heat generated in burning waste. Therefore, it is a very
important subject to remove hazardous material from exhaust gas
generated in an incinerator. Especially, removal of dioxin has been
a very pressing subject.
[0014] The apparatuses disclosed in JP-A-286835/1990,
JP-A-332166/1993 and JP-A-332167/1993 are mainly used for a gas
turbine power generation system, the above-mentioned subject is out
of question because of using fuel different from the waste.
Therefore, the conventional reformer is not based on the subject.
Further, since various kinds of waste is burned in an incinerator,
the amount of generated heat changes hour by hour, month by month
and year by year. Consequently, since the amount of fuel fed to an
fuel reformer changes, corresponding to the amount and the
components of gas exhausted from the incinerator, an existing
direct heat exchange type fuel reformer has the following problem,
that is, a fire-proofing brick structure part inside the
incinerator is easily damaged and worn out due to the changes of
the generated heat.
SUMMARY OF THE INVENTION
[0015] Objectives of the Invention:
[0016] The present invention has been achieved in considering the
above-mentioned problems, and objectives of the present invention
are as follows.
[0017] The first objective of the present invention is to provide a
waste-to-energy incineration system which are able to stably
decompose generated dioxin, in which the composition and the heat
value of exhaust gas largely changes in a long and a short periods,
and a fuel reformer used there,.
[0018] The second objective of the present invention is to provide
a waste-to-energy incineration system and a fuel reformer which are
able to stably decompose generated dioxin and to suppress NOx
generation.
[0019] The third objective of the present invention is to provide a
waste-to-energy incineration system having a highly reliable
performance of dioxin decomposition and a highly efficient
waste-to-energy incineration performance.
[0020] Method of Solving the Problem:
[0021] To attain the above-mentioned first and third objectives,
the present invention provides a waste-to-energy incineration
system, comprising:
[0022] an incinerator for burning waste;
[0023] a boiler in the incinerator for generating steam by using
exhaust heat generated by the incinerator;
[0024] a superheater for superheating steam generated in the
boiler;
[0025] a steam turbine driven by steam superheated by the
superheater;
[0026] a generator driven by the steam turbine;
[0027] a fuel reformer for reforming fuel; and
[0028] a combustor burning fuel gas which is reformed by the fuel
reformer, and at least a part of incinerator exhaust gas.
[0029] Further, in a waste-to-energy incineration system, the
system comprises:
[0030] an incinerator for burning waste;
[0031] a boiler in the incinerator for generating steam with
exhaust heat generated in the incinerator;
[0032] a steam utilizer for utilizing steam generated in the
boiler; and
[0033] a fuel reformer for reforming fuel;
[0034] wherein fuel gas reformed by said fuel reformer is led to
said incinerator.
[0035] Further, in a waste-to-energy incineration system, the
system comprises:
[0036] an incinerator for burning waste;
[0037] a boiler in the incinerator for generating steam with
exhaust heat generated in the incinerator;
[0038] a steam utilizer for utilizing steam generated in the
boiler;
[0039] another boiler different from the boiler; and
[0040] a fuel reformer for reforming fuel;
[0041] a combustor for burning fuel gas which is reformed by the
reformer, and at least a part of incinerator exhaust gas;
[0042] wherein steam generated by the another boiler is led to the
fuel reformer.
[0043] To attain the above-mentioned second objective, the present
invention provides a waste-to-energy incineration system,
comprising:
[0044] an incinerator for burning waste;
[0045] a boiler in the incinerator for generating steam by using
exhaust heat generated in the incinerator;
[0046] a superheater for reheating steam generated in the
boiler;
[0047] a steam turbine driven by steam led from the
superheater;
[0048] a generator driven by the steam turbine;
[0049] a fuel reformer for partially oxidizing the amount more than
20% of source fuel; and
[0050] a combustor for burning fuel gas which is reformed by the
fuel reformer, and at least a part of incinerator exhaust gas.
[0051] In the above-mentioned waste-to-energy incineration systems,
steam extracted from a steam feed-water system consisting of the
incinerator boiler, the superheater, and the steam turbine or the
steam utilizer is used as cooling medium injected in the fuel
reformer. Further, at a place of the steam feed-water system, a
feed-water evaporator utilizing exhaust gas from the combustor as a
heat source is provided, and steam generated from water heated by
the feed-water evaporator is used as cooling medium injected in the
fuel reformer.
[0052] Further, the above-mentioned fuel reformer includes a first
chamber for reforming fuel and a second chamber neighboring the
first chamber, at the outside of the first chamber, for leading
steam as cooling medium into the first chamber.
[0053] Further, in the first chamber, fuel gas is obtained by
partially oxidizing source fuel and the fuel gas is reformed.
Further, the furl reformer includes a fuel flowing path (referred
as a fuel flowing chamber) and a cooling jacket. In the fuel
flowing chamber, fuel gas is obtained by partially oxidizing more
than 20% of raw fuel, and the fuel gas is reformed. Further, the
cooling jacket is arranged, neighboring the fuel flowing chamber,
at the outside of the fuel flowing chamber, for leading steam as
cooling medium from at least one hole or a tube into the fuel
flowing chamber. Furthermore, the fuel flowing chamber is composed
of sub-chambers having different sectional areas. Moreover, the
first chamber has a swirling means for generating a swirling flow
of the cooling medium.
[0054] The above-mentioned fuel reformer includes a source fuel
feeding means, a cooling medium feeding means, a first chamber for
generating fuel gas by partially oxidizing source fuel fed by the
source fuel feeding means and reforming the fuel gas, and a second
chamber arranged, neighboring the first chamber, at the outside of
the first chamber, for leading cooling medium fed by the cooling
medium feeding means into the first chamber.
[0055] Further, the above-mentioned fuel reformer includes a source
fuel feeding means, a cooling medium feeding means, a fuel flowing
chamber for generating fuel gas by partially oxidizing source fuel
fed by the source fuel feeding means and reforming the fuel gas,
and a cooling jacket arranged, neighboring the fuel flowing
chamber, for leading steam as cooling medium fed by the cooling
medium feeding means from at least one place into the fuel flowing
chamber, wherein the amount more than 20% of source fuel is
partially oxidized.
[0056] Furthermore, the above-mentioned fuel flowing chamber is
composed of parts having different sectional areas.
[0057] Moreover, the first chamber has a swirling means for
generating a swirling flow of the cooling medium.
[0058] To attain the above-mentioned second objective, the present
invention provides a waste-to-energy incineration system, wherein a
part of exhaust gas generated in the incinerator is led to the fuel
reformer as oxidizer together with air or oxygen. Further, at least
a part of the exhaust gas generated in the incinerator is led to
the combustor as oxidizer together with air or oxygen.
[0059] To attain the above-mentioned third objective, the present
invention provides a waste incineration processing system,
comprising:
[0060] an incinerator for burning waste;
[0061] a boiler in the incinerator, for generating steam with
exhaust heat generated in the incinerator;
[0062] a steam utilizer utilizing steam generated in the boiler;
and
[0063] a fuel reformer;
[0064] wherein fuel reformed by the fuel reformer is injected into
the incinerator, and burned.
[0065] Moreover, the present invention provides a waste
incineration processing system, comprising:
[0066] an incinerator for burning waste;
[0067] a boiler for generating steam;
[0068] a fuel reformer for reforming fuel; and
[0069] a combustor for burning fuel gas which is reformed by the
fuel reformer, and at least a part of incinerator exhaust gas;
[0070] wherein steam generated in the boiler is led into the fuel
reformer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0071] FIG. 1 is a system diagram of a waste-to-energy incineration
system of an embodiment according to the present invention.
[0072] FIG. 2 is a vertical sectional view of a fuel reformer of an
embodiment.
[0073] FIG. 3 is one of variations of the system shown in FIG.
1.
[0074] FIG. 4 is another of variations of the system shown in FIG.
1.
[0075] FIG. 5 is a system diagram of a waste-to-energy incineration
system of another embodiment according to the present
invention.
[0076] FIG. 6 is one of variations of the system shown in FIG.
5.
[0077] FIG. 7 is a system diagram of a waste-to-energy incineration
system of further another embodiment according to the present
invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0078] At first, details of the present invention will be explained
with reference to an embodiment shown in FIG. 1-FIG. 4. FIG. 1 is a
system diagram of a waste-to-energy incineration system of an
embodiment according to-the present invention, and FIG. 2 is a
vertical sectional view of a fuel reformer of an embodiment. In
each of FIG. 3-FIG. 5, a composition of variation examples of the
waste-to-energy incineration system shown in FIG. 1, are shown.
[0079] As shown in FIG. 1, the waste-to-energy incineration system
is divided into main two systems, that is, a steam turbine systems
and an exhaust gas system including a fuel reformer. In an
incinerator 19, a part for storing waste 16 is provided, and air is
injected into the incinerator 19 from the part for storing waste 16
by a compressed fan 17. The air injected into the incinerator 19 is
used as waste burning air. The burned waste gas 20 generated in the
incinerator is sent to a dust collector 26 via an exhaust gas pipe
24 after flowing through an incinerator boiler 23.
[0080] The air feeding pipe 7 is provided at the part for storing
waste 16 and connected to a fuel reformer 29 to which a fuel
feeding pipe 6 is connected. In the downstream of the fuel reformer
29, a combustor 28 is connected to the fuel reformer 29. Further,
in the down stream of the combustor 28 is connected to a
superheater 31 with a burned-up waste exhaust gas pipe 30. Steam
passes through the superheater 31, and flows into a steam turbine
34 via superheated steam pipe 32. A generator 35 connected to the
steam turbine 34 is driven and rotated by the superheated steam
passing through the superheated steam pipe 32, and the rotated
generator 35 generate electrical power. A part of the steam flowing
in the steam turbine 34 and rotating the turbine 34 is extracted
and fed back to the fuel reformer 29 through a pipe 15. The rest
part of the steam is led to a condenser 36 after rotating the steam
turbine 34 and condensed to water. The condensed water is fed to
the incinerator boiler 23 by a feed water pump 37 via a feed water
pipe 21.
[0081] Further, dust in the burned-up waste gas 20 sent to the dust
collector 26 is collected by the dust collector 26. A part or the
whole of the burned-up waste gas 20 is fed to the combustor 28
after passing through the dust collector 26. The rest gas is sent
to an exhaust gas stack 25 by an induced fan 27, and is discharged
from the stack 25.
[0082] The composition of the fuel reformer is shown in FIG. 2. The
outside of the cylindrical fuel reformer 29 is covered by an
insulator layer 1, and a fuel flowing chamber 3 surrounded by
cylindrical partitions 2a and 2b in the central line axis direction
is provided. The insulator layer 1 is provided to prevent heat from
dissipating, for example, by radiating from the fuel reformer 29,
to which heat insulation material such as glass wool, ceramic wool,
etc. is used. The cylindrical partitions 2a and 2b are composed of
two different diameter parts, in the inside part of which a cooling
jacket 4 is provided. The partitions composed of 2a and 2b can be
freely expanded and contracted in the horizontal direction by
inserting a spacer 5 between the two partitions 2a and 2b.
[0083] Further, the fuel feeding pipe 6 and the air feeding pipe 7
are provided in the vicinity of the central axis part in the upper
stream of the fuel flowing chamber 3, and these pipes forms an
entrance from which fuel-steam mixture gas is injected into the
fuel flowing chamber 3. The gas injected into the fuel flowing
chamber 3 is ignited by an ignitor 11. A cooling medium, namely,
cooling steam feeding pipe 8 is provided in the upper stream of the
cooling jacket 4. Further, a plurality of injection holes 9 are
provided at the partitions 2a and 2b so that the cooling steam
entering the cooling jacket 4 is injected into the fuel flowing
chamber 3. Furthermore, an fuel exit 10 for ejecting the fuel gas
including hydrogen, reformed in the fuel, is provided in the down
stream, and is connected to the combustor 28 as mentioned
above.
[0084] In the following, operations of the fuel reformer 29 having
the above-mentioned composition are explained. A mixture gas 12 of
fuel such as hydrocarbon (heavy oil is used as fuel in the
embodiment) mixed with steam at the predetermined ratio is fed to
the fuel flowing chamber 3 via the fuel feeding pipe 6, and air 13
is fed to the fuel flowing chamber 3 via the air feeding pipe 7.
Further, the mixture gas 12 and the air 13 are ignited by the
ignitor 11, and the diffused combustion is generated and kept. The
flow rate of the air 13 fed to the fuel flowing chamber 3 via the
air feeding pipe 7 is adjusted so as to burn more than 20% of the
mixture gas 12 (gas obtained by evaporating heavy oil used as fuel
fed to the fuel flowing chamber 3 via fuel feeding pipe 7. The
mixture gas 12 is partially burned, and a high temperature fuel gas
including non burned-up gas and reaction heat necessary to reform
the fuel gas can be simultaneously obtained. The mixture gas 12 fed
to the fuel flowing chamber 3 via the fuel feeding pipe 6 is
obtained by mixing fuel such as hydrocarbon with steam at the
predetermined ratio. It is possible to set the mixing timing before
fuel and steam are fed into the fuel feeding pipe 6 or when both
fuel and steam are fed into the fuel feeding pipe 6 from
predetermined places of the pipe 6.
[0085] Further, steam 14 is fed into the cooling jacket 4 via the
cooling medium feeding pipe 8. The steam 14 fed into the cooling
jacket 4 cools the cylindrical partitions 2 exposed to the high
temperature fuel gas to be reformed, from the outside of the
partitions 2. After cooling the cylindrical partitions 2, the steam
14 fed into the cooling jacket 4 is injected from a plurality of
injection holes into the fuel flowing chamber 3, and is mixed with
the high temperature fuel gas generated by burning the mixture gas.
With heat of burning fuel and the steam 14, the reaction shown in
the following equation (1) occurs, and the fuel gas is reformed so
as to include hydrogen. The above-mentioned reaction is called as a
steam reforming reaction, and the reaction is an endothermic
reaction, in which the mixture of hydrocarbon and steam is changed
to gas including hydrogen.
[0086] The reaction equation (1):
C.sub.mH.sub.n+sH.sub.2O.fwdarw.hH.sub.2+c1CO+c2CO.sub.2-.DELTA.Q
(1)
[0087] where, C.sub.mH.sub.n is hydrocarbon contained in heavy oil,
s, h, c1 and c2 are coefficients, and .DELTA.Q is the reaction
heat.
[0088] The gas including hydrogen, obtained by the abovementioned
process is fed to the combustor 28 from the fuel exit 10.
[0089] As mentioned above, since in the fuel reformer of the
embodiment the cooling jacket 4 is arranged so as to surround the
fuel flowing chamber 3 formed with the cylindrical partitions, and
the steam 14 is fed into the cooling jacket 4 to cool the
partitions 2 so that the partitions 2 are cooled from their
outside. Therefore, the partitions 2 heated to a high temperature
by the high temperature fuel gas is protected by the
above-mentioned cooling method. Thus, the high temperature
heat-proofing reliability of the fuel reformer 29 is improved in
the embodiment. That is, since in the first chamber connected a
fuel flowing path, the second chamber in which the cooling jacket 4
is provided, cools the fuel flowing chamber 3 from its outside by
feeding the steam 14 as cooling medium into the cooling jacket 4,
the fuel flowing chamber 3 exposed to the high temperature fuel gas
is protected from damage by the high temperature fuel gas. Further,
after cooling the partitions 2 of the fuel flowing chamber 3, the
temperature of the steam 14 is increased to the temperature
adequate for reforming fuel, and mixed with the fuel gas to be
reformed. Furthermore, the fuel gas mixed with the heated steam 14
is reformed with the heat generated by partially oxidizing
(combustion) more than 20% of the source fuel.
[0090] Moreover, since a diffused combustion method as a combustion
method is used, the mixture gas fed from the fuel feeding pipe 6
and the air 13 fed from the air feeding pipe 7 are certainly
ignited. That is, the combustion range in the fuel concentration
can be made so wide that fuel can be burned in its combustible
range, since by feeding the mixture gas 12 (fuel) and the air 13
separately, it is possible to adjust the amounts of air and fuel to
be fed, respectively. Thus, by adopting the diffused combustion
method, it is possible to certainly ignite fuel mixture gas, due to
the widened combustible range of the used fuel.
[0091] After the certainly performed ignition, since it is possible
to keep fuel combustion in the fuel flowing chamber 3 with the
combustion heat generated by the ignition, the reliability of fuel
reforming in the fuel flowing chamber 3 of the fuel reformer 29 is
improved. Now, the fuel flowing chamber 3 is formed by the first
cylindrical partition 2a and the second cylindrical partition 2b
having different diameters, respectively. Diameter Da of the first
cylindrical partition 2a is smaller than diameter Db of the second
cylindrical partition 2b, these cylindrical partitions having the
different diameters, respectively, are overlapped at their
neighboring terminal parts opposite to each other. Since a gap part
is formed between the two overlapped terminal parts of the two
cylindrical partitions 2a and 2b having the different diameters,
respectively, a resilient spacer 5 of which a sectional view is a S
character shape, is inserted into the gap so as to elastically
support the two cylindrical partitions having the different
diameters. As the sizes of the diameters, for example, Da and Db
are set to 350 mm and 370 mm, and the gap is set to about 10 mm.
The spacer 5 is usually called a spring seal, and in the case that
the cylindrical partitions having different diameters,
respectively, are overlapped, fluid is prevented from leaking out
of the gap formed between the two overlapped parts by line contacts
in the circumference direction formed by the spacer 5. The spacer
machined so as to have slit type cuts in the central axis direction
has the elasticity, and is called a usually used flared seal. Since
the cylindrical partitions 2 are cooled from their outsides by the
steam 14 and heated from their inside by the high temperature fuel
gas to be reformed, both expansion and contraction strains act on
the partitions 2. In the embodiment, in order to absorb the
expansion and the contraction, the fuel flowing chamber 3 is formed
the first partition 2a and second partition 2b having different
diameters, whereby the allowance to the simultaneously occurring
expansion and contraction is prepared for the partitions 2. The
abovementioned structure composing the fuel flowing chamber 3 can
prevent the strength degradation of itself, and does not give bad
effects on other members composing the fuel reformer 29, which
improve the lifetime of the components of the fuel reformer 29.
Thus, the reliability in heat-proofing of the fuel reformer 29 is
improved. Moreover, since the fuel flowing chamber 3 possesses a
plurality of fuel flowing serial sub-chambers having different
diameters, the thermal strain changes due to the expansion and the
contraction occurring in the members composing the plurality of
fuel flowing sub-chambers caused by changes of the amount of the
exhaust gas or the generated heat is also suppressed by adjusting
the amounts of the fed fuel and the fed steam.
[0092] In the following, operations of the waste-to-energy
incineration system using the above-mentioned fuel reformer. With
feed-water led through a feed water pipe 21 from the steam turbine
system, steam is obtained by heat exchange in the incinerator
boiler 23 by using the burned-up waste gas 20 generated by burning
waste 16 with air 18 pushed into the incinerator 19 by the
compressed fan 17. Dust, NOx, a part of residual, etc. included in
the exhaust gas output from the incinerator 19 are removed by the
dust collector 26, and a part or the whole of the cleaned-up
exhaust gas is extracted from a gas stream after the dust collector
26. The extracted exhausted gas is led to the combustor 28, and is
used in place for air. The rest of the exhaust gas is discharged
from the exhaust stack 25 to the atmosphere by the induced fan
27.
[0093] The exhaust gas system is also utilized to superheat steam
generated in the incinerator boiler 23, with exhaust gas generated
by burning the fuel gas. The mixture gas is obtained by mixing gas
or mist fed from the fuel feeding pipe 6, which is gained from the
evaporated heavy oil as the source fuel, and with air fed from the
air feeding apparatus 38. By using the mixture gas, gas including
hydrogen is obtained by reforming fuel gas gained by partially
oxidizing more than 20% of the source fuel (partial combustion)
with steam extracted from the steam turbine 34, into the fuel
reformer 29. Further, in the combustor 28, the exhaust gas 39
extracted from the gas flow after the dust collector 26 is burned
with the gas including hydrogen, obtained in the fuel reformer 29.
In the process, the system is composed so that the exhaust gas 39
resides for more than 1 sec. under the condition of temperature
higher than 700.degree. C., so that dioxin in the exhaust gas 39 is
decomposed, and the exhaust gas 39 which passed the superheater 31,
is discharged to the atmosphere. In the embodiment, the combustion
performance of the combustor 28 is improved by using the gas
reformed by the fuel reformer 29. Thus, the fuel gas improved in
combustibility by reforming fuel helps the incinerator exhaust gas
to burn completely at the high temperature for the predetermined
time so as to decompose perfectly the dioxin in the incinerator
exhaust gas. Furthermore, the burned-up exhaust gas generated in
the combustor 28 is also used as a superheating heat source of the
superheater 31 in which steam generated in the incinerator boiler
23 is superheated.
[0094] In the steam turbine system, the steam turbine 34 is driven
by the steam superheated in the superheater 31, and the generator
35 driven by the steam turbine 34 generates power. The steam which
has driven the steam turbine 34 is condensed into water in the
condenser 36, the condensed water is fed to and utilized in the
incinerator 19.
[0095] Further, in the embodiment, Dioxin included in the exhaust
gas is decomposed. Further, the cleaned-up exhaust gas is passed
through the superheater 31, and increases the temperature of the
about saturated steam of 300.degree. C. at the pressure of 30 ata,
which is generated in the incinerator boiler 23, to about
500.degree. C. Since the heat difference between the superheated
steam and the condensed water is expanded by the above-mentioned
steam superheating process, the high efficiency of power generation
system can be realized by increasing the output power and the
efficiency of the steam turbine.
[0096] Furthermore, since an additional heat source and an
apparatus generating the heat source can be omitted by using the
steam extracted from the steam turbine 34 as the steam for
reforming fuel in the fuel reformer 29, a waste-to-energy
incineration system realizing the high reliability can be
provided.
[0097] FIG. 3 is one of variations of the embodiment shown in FIG.
1, in which a part of the exhaust gas fed to the combustor 28 is
injected into the air feeding pipe 7 for feeding air, so as to be
fed to the fuel reformer 29.
[0098] The above-mentioned composition has an effect of
contributing to efficiency improvement of the fuel reformer 29
since the temperature of air can be increased by using the exhaust
gas.
[0099] FIG. 4 is another of variations of the embodiment shown in
FIG. 1, in which the incinerator exhaust gas is injected into the
air feeding pipe 7 for feeding air, further, an air stream is
branched after the air feeding apparatus 38, and one of the
branched air atriums is fed to the reformer 29 and the other to the
combustor 28.
[0100] By using the above-mentioned composition, it is possible to
adjust the respective flow rates of the mixture gas of air and
exhaust gas fed to the fuel reformer 29 and the combustor 28,
corresponding to the mixture gas flow rate needed in each of the
fuel reformer 29 and the combustor 28. Therefore, the composition
has also an effect of contributing to realization of a high
reliable waste-to-energy incineration system in which fuel is
stably burned and reformed even at states of a low amount of the
exhaust gas or an extremely low oxygen concentration of the exhaust
gas. Furthermore, since the stable temperature necessary to
decompose dioxin can be kept even at a state of an extremely low
oxygen concentration of the exhaust gas, by mixing the exhaust gas
fed to the combustor 28 with air, it becomes possible to realize a
highly efficient waste-to-energy incineration system having an
excellent dioxin decomposing function.
[0101] In the following, other embodiments of the present invention
are explained by referring to FIG. 5-FIG. 7. FIG. 5 shows a
composition of a waste-to-energy incineration system of another
embodiment, and FIG. 6 shows of a composition of one variation of
the embodiment shown in FIG. 5.
[0102] As shown in FIG. 5, in the waste-to-energy incineration
system of the embodiment, the steam fed to the fuel reformer 29 is
not extracted from the steam flowing in the steam turbine 34, but
the steam obtained by exchanging heat of the exhaust gas which
passed through the superheater, with a part of the condensed water,
in a feed water evaporator 40, is fed to the fuel reformer 29. That
is, in the embodiment, water led by a feed water pump 41 is
evaporated during passing through the feed water evaporator 40, and
fed into the fuel reformer 29.
[0103] The above-mentioned composition has an effect of
contributing to improvement of fuel and to realization of a highly
efficient waste-to-energy incineration system, since it is possible
to feed steam to the fuel reformer 29 without decreasing the output
of the steam turbine 34 due to steam extraction from steam flowing
in the steam turbine 34, further to feed steam to the fuel reformer
29 under the optimal conditions of temperature and pressure because
of independency from any constraint as to steam extraction.
[0104] FIG. 6 shows one variation of the embodiment shown in FIG.
5, in which a part of feed water flow branched at the feeding water
flow after the feed water pump 37 is led to the feed water
evaporator 40. The feed water flow passing through the feed water
evaporator 40 is changed to a steam flow, and the steam flow is
branched to two steam flows. One of the steam flows is mixed with
the steam from the incinerator boiler 23, and the other one is fed
to the fuel reformer 29. A heat source of the feed water evaporator
40 is the exhaust gas flowing after the superheater 31, and the
heat in the exhaust gas is recovered by the feed water evaporator
40.
[0105] By using the above-mentioned composition, a highly efficient
waste-to-energy incineration system is realized since the steam
flow rate driving the steam turbine 34 can be increased by
generating steam fed to the superheater 31 with the exhaust gas
output from the combustor 28. Further, a more highly efficient
waste-to-energy incineration system is realized since the output
power is increased by increasing the steam fed to the fuel reformer
29 by using the evaporated feed water, in addition to the increase
of steam flowing in the steam turbine 34.
[0106] Another embodiment of the present invention is explained by
referring to FIG. 7 as follows. FIG. 7 shows a system diagram of a
waste-to-energy incineration system of this embodiment.
[0107] As shown in FIG. 7, in the embodiment, fuel gas output from
the fuel reformer 29 is injected into the incinerator 19, and the
second fuel burning is performed in the incinerator 19. Further,
differently from the embodiments shown in FIG. 1-FIG. 6, gas
exhausted from the incinerator 19 is not fed to the fuel reformer
29, and discharged from the exhaust stack 25 via the dust collector
26 and the induced fan 27. Moreover, a steam system is composed of
the incinerator boiler 23, a steam utilizer 42 (a steam turbine, a
cooler utilizing steam, a warm water swimming pool, etc. and a feed
water pump 37. Further, steam is extracted from a place in the
steam system and fed to the fuel reformer 29.
[0108] By using the above-mentioned composition, since it is
possible to make a long and large region of the high temperature at
which dioxin can be decomposed in the incinerator 19, which also
make the resident time of the exhaust gas in the above-mentioned
high temperature region long, the temperature and time necessary to
decompose dioxin is secured. Thus, a highly efficient
waste-to-energy incineration system having an excellent dioxin
decomposing function can be realized. Moreover, since the high
temperature burning-up region is enlarged and elongated, the time
necessary for the exhaust gas to pass the high temperature region
becomes longer. If the above-mentioned resident time increases,
dioxin decomposition reaction exponentially progresses. The waste
processing system having an incinerator capable of greatly reducing
dioxin can be provided. Thus, by applying the embodiment, it is
possible to provide a waste incinerator or a waste-to-energy
incineration system discharging little hazard material to the
environment.
[0109] As explained above, by using the present invention, since
low heat valued fuel gas, included in the burned-up gas used for
superheating steam generated in an incinerator boiler, can be
generated by burning fuel gas obtained by reforming liquid fuel, so
as to burn more than 20% of the source fuel, it is possible to form
a stable high temperature burning-up field, namely, a dioxin
decomposing field. Thus, it has become possible to provide a highly
efficient and reliable waste-to-energy incineration system capable
of almost completely reducing dioxin and efficiently recovering
exhaust heat generated in the system.
* * * * *