U.S. patent application number 11/224059 was filed with the patent office on 2006-01-19 for heavy oil reforming method, an apparatus therefor, and gas turbine power generation system.
Invention is credited to Nobuyuki Hokari, Hiromi Koizumi, Tomohiko Miyamoto, Atsushi Morihara, Hirokazu Takahashi.
Application Number | 20060011511 11/224059 |
Document ID | / |
Family ID | 34394158 |
Filed Date | 2006-01-19 |
United States Patent
Application |
20060011511 |
Kind Code |
A1 |
Hokari; Nobuyuki ; et
al. |
January 19, 2006 |
Heavy oil reforming method, an apparatus therefor, and gas turbine
power generation system
Abstract
The purpose of the invention is to provide a heavy oil reforming
method which reforms a heavy oil to give a fuel suitable for a gas
turbine, eliminates sulfur and vanadium, i.e., harmful components,
from a heavy oil, and enables almost all the hydrocarbons in the
heavy oil to be used in gas turbine combustion; an apparatus
therefor; and a gas turbine power generation system using the
reformed heavy oil as fuel. This method comprises reacting a heavy
oil with supercritical water and then with a scavenger for sulfur
and vanadium to eliminate sulfur and vanadium from the heavy oil.
The apparatus for reforming a heavy oil is equipped with a reactor
for reacting a heavy oil with supercritical water, a scavenging
apparatus filled with a scavenger for scavenging sulfur and
vanadium in the heavy oil, and a connecting pipe for connecting the
reactor and the scavenging apparatus. The gas turbine power
generation system has a burner for burning a heavy oil reformed
with the reforming apparatus and a gas turbine driven by a
combustion gas generated by the burner.
Inventors: |
Hokari; Nobuyuki;
(Hitachinaka, JP) ; Miyamoto; Tomohiko; (Takahagi,
JP) ; Takahashi; Hirokazu; (Hitachinaka, JP) ;
Morihara; Atsushi; (Hitachinaka, JP) ; Koizumi;
Hiromi; (Hitachi, JP) |
Correspondence
Address: |
DICKSTEIN SHAPIRO MORIN & OSHINSKY LLP
2101 L Street, NW
Washington
DC
20037
US
|
Family ID: |
34394158 |
Appl. No.: |
11/224059 |
Filed: |
September 13, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10679397 |
Oct 7, 2003 |
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11224059 |
Sep 13, 2005 |
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Current U.S.
Class: |
208/106 ;
208/208R; 208/213; 208/251R; 208/253; 422/600 |
Current CPC
Class: |
F02C 3/20 20130101; B01J
3/008 20130101; C01B 3/36 20130101; B01J 2219/00006 20130101; C01G
31/02 20130101; Y02P 20/54 20151101; C01B 2203/0255 20130101; B01J
8/025 20130101; C01B 3/34 20130101; B01J 8/0055 20130101; C01B
2203/1247 20130101; Y02P 20/544 20151101; C01B 2203/0216 20130101;
B01J 8/065 20130101; Y02P 20/129 20151101 |
Class at
Publication: |
208/106 ;
208/208.00R; 208/251.00R; 208/213; 208/253; 422/188; 422/190 |
International
Class: |
C10G 9/00 20060101
C10G009/00; C10G 45/00 20060101 C10G045/00; B01J 10/00 20060101
B01J010/00; B01J 8/04 20060101 B01J008/04 |
Claims
1-6. (canceled)
7. A heavy oil reforming method which comprises reacting a heavy
oil containing at least one of vanadium and sulfur with water,
which is in a state of high temperature and high pressure, in the
presence of a reaction accelerator, and then bringing said heavy
oil, along with said high-temperature and high-pressure water, into
contact with a scavenger for scavenging vanadium and/or sulfur in
the heavy oil to thereby eliminate vanadium and/or sulfur from the
heavy oil.
8. The method according to claim 7 wherein the reaction accelerator
comprises at least one substance selected from alkali metal,
alkaline earth metal, hydrogen peroxide solution, nitric acid,
nitrate and formic acid.
9. An apparatus for reforming a heavy oil comprising a reactor for
reacting a heavy oil containing at least one of vanadium and sulfur
with water which is in a state of high temperature and high
pressure, a scavenging apparatus filled with a scavenger for
scavenging sulfur and/or vanadium in the heavy oil, and a
connecting pipe for connecting the reactor and the scavenging
apparatus; wherein said scavenging apparatus has an inlet port for
introducing the heavy oil along with the high-temperature and
high-pressure water after the reaction and has a discharge port for
discharging the reformed heavy oil.
10. The apparatus according to claim 9 wherein the scavenging
apparatus is filled with at least one substance selected from iron
oxide, nickel oxide, metal oxide which forms composite oxide with
vanadium, ceramics which adsorb vanadium oxide, calcium compound,
solid carbon, hydrocarbon, alumina and silica.
11. The apparatus according to claim 9 further comprising a means
for adding a reaction accelerator to the high-temperature and
high-pressure water supplied to the reactor.
12. The apparatus according to claim 11 wherein at least one
substance selected from alkali metal, alkaline earth metal,
hydrogen peroxide solution, nitric acid, nitrate and formic acid is
added to the high-temperature and high-pressure water by the
reaction accelerator adding means.
13. A gas turbine power generation system having a gas turbine
driven by a combustion gas generated by burning a heavy oil
reformed by using the heavy oil reforming apparatus set forth in
claim 9.
14. The gas turbine power generation system according to claim 13
wherein the heavy oil reforming apparatus is disposed in a fuel
supply system which supplies fuel to a gas turbine burner.
15. The gas turbine power generation system according to claim 14
further comprising an exhaust gas heat exchanger for heating water
to be supplied to the reactor in the heavy oil reforming apparatus
by the exhaust gas released after the gas turbine has been
driven.
16. A heavy oil reforming method which comprises reacting a heavy
oil containing at least one of vanadium and sulfur with water,
which is in a state of being heated to 300.degree. C. to
500.degree. C. and pressured to 10 MPa to 30 MPa, in the presence
of a reaction accelerator, and then bringing said heavy oil, along
with said water, into contact with a scavenger for scavenging
vanadium and/or sulfur in the heavy oil to thereby eliminate
vanadium and/or sulfur from the heavy oil.
17. A heavy oil reforming method which comprises reacting a heavy
oil containing vanadium with water, which is in a state of being
heated to 300.degree. C. to 500.degree. C. and pressured to 10 MPa
to 30 MPa, in the presence of a reaction accelerator, and then
scavenging the vanadium contained in the heavy oil in the form of
vanadium oxide to thereby eliminate vanadium from the heavy oil.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a heavy oil reforming
method, an apparatus therefor, and a gas turbine power generation
system using the reformed heavy oil as fuel.
BACKGROUND OF THE INVENTION
[0002] Various techniques for reforming heavy oils for use as fuel
for the gas turbines have been proposed. There are known, for
instance, a method in which the hydrocarbons in a heavy oil are
decomposed with supercritical water to convert the heavy oil to a
lighter type and a combustible gas is produced therefrom
(JP-A-11-246876), and a proposal in which the produced gas is
burned to drive a gas turbine while the residue left after oil
conversion to a lighter type is burned by a boiler, using the
generated heat for producing electric power by a steam turbine
(JP-A-11-80750). These techniques may be boiled down to an idea of
taking out part of the hydrocarbons in a heavy oil to concentrate
the harmful components in the residue.
SUMMARY OF THE INVENTION
[0003] The method of generating a gas from a heavy oil with
supercritical water, as stated above, is capable of reforming part
of a heavy oil to provide a fuel suited for a gas turbine, but
incapable of making all the hydrocarbons in a heavy oil applicable
as fuel. Also, since the harmful components are concentrated in the
residue, enlargement of the environmental protection equipment and
measures against corrosion are required on the part of the boilers
used for burning such oil.
[0004] The purpose of the invention is to provide a heavy oil
reforming method which reforms a heavy oil to give a fuel suitable
for a gas turbine, eliminates sulfur and/or vanadium, which are the
harmful components, from a heavy oil, and enables almost all the
hydrocarbons in the heavy oil to be used in gas turbine combustion:
an apparatus therefor; and a gas turbine power generation system
using the reformed heavy oil as fuel.
[0005] The present invention provides a heavy oil reforming method
which comprises reacting a heavy oil containing at least one of
vanadium and sulfur with water which is in a state of high
temperature and high pressure, and then bringing said heavy oil,
along with said high-temperature and high-pressure water, into
contact with a scavenger for scavenging vanadium and/or sulfur in
the heavy oil to thereby eliminate vanadium and/or sulfur from the
heavy oil.
[0006] In the present invention, the high-temperature and
high-pressure water is preferably in a state of being heated to
300.degree. C. to 500.degree. C. and pressured to 10 MPa to 30 MPa.
More preferably, it is in a supercritical or subcritical state.
[0007] The scavenger used for eliminating at least one of sulfur
and vanadium in the present invention preferably comprises at least
one compound selected from iron oxide, nickel oxide, metal oxide
which forms composite oxide with vanadium, ceramics which adsorb
vanadium oxide, calcium compound, solid carbon such as activated
carbon and coke, and hydrocarbon such as asphalt and tar, alumina,
and silica.
[0008] Vanadium in the heavy oil is preferably scavenged in the
form of vanadium oxide or a metallic compound of vanadic acid by
the scavenger, while sulfur in the heavy oil is preferably
scavenged in the form of a sulfate or metallic sulfide.
[0009] The present invention also provides a heavy oil reforming
method which comprises reacting a heavy oil containing at least one
of vanadium and sulfur with water, which is in a state of high
temperature and high pressure, in the presence of a reaction
accelerator, and then bringing said heavy oil, along with said
high-temperature and high-pressure water, into contact with a
scavenger for scavenging vanadium and/or sulfur in the heavy oil to
thereby eliminate vanadium and/or sulfur from the heavy oil.
[0010] The reaction accelerator used in the above process
preferably comprises at least one substance selected from alkali
metal, alkaline earth metal, hydrogen peroxide solution, nitric
acid, nitrate and formic acid.
[0011] Further, the present invention provides an apparatus for
reforming a heavy oil comprising a reactor for reacting a heavy oil
containing at least one of vanadium and sulfur with water which is
in a state of high temperature and high pressure, a scavenging
apparatus filled with a scavenger for scavenging sulfur and/or
vanadium in the heavy oil, and a connecting pipe for connecting the
reactor and the scavenging apparatus; wherein said scavenging
apparatus has an inlet port for introducing the heavy oil along
with the high-temperature and high-pressure water after the
reaction and has a discharge port for discharging the reformed
heavy oil.
[0012] The scavenging apparatus is preferably filled with at least
one substance selected from iron oxide, nickel oxide, metal oxide
which forms composite oxide with vanadium, ceramics which adsorb
vanadium oxide, calcium compound, solid carbons such as activated
carbon and coke, alumina, and silica.
[0013] The heavy oil reforming apparatus according to the present
invention is preferably equipped with a means for adding a reaction
accelerator to the high-temperature and high-pressure water
supplied to the reactor. Preferably, by this reaction accelerator
adding means, at least one substance selected from alkali metal,
alkaline earth metals, hydrogen peroxide solution, nitric acid,
nitrate and formic acid is added to the high-temperature and
high-pressure water.
[0014] The present invention also provides a gas turbine power
generation system comprising the said heavy oil reforming
apparatus, a gas turbine burner for burning the heavy oil reformed
by the heavy oil reforming apparatus, and a gas turbine driven by
the combustion gas generated by the gas turbine burner.
[0015] In this gas turbine power generation system, the heavy oil
reforming apparatus can be incorporated in a fuel supply system
which supplies fuel to the gas turbine burner.
[0016] The power generation system can also comprise an exhaust gas
heat exchanger for heating water to be supplied to the reactor in
the heavy oil reforming apparatus by the exhaust gas released after
the gas turbine has been operated.
[0017] According to the present invention, a heavy oil is mixed
with high-temperature and high-pressure water, such as
supercritical or subcritical water, and by availing of its
properties as a solvent for organic matter and its action as a
hydrolyzing agent, the substances to be removed such as sulfur and
vanadium in the heavy oil are eliminated from inside the cyclic
hydrocarbon molecules or porphyrin structure in the heavy oil, and
the eliminated substances are scavenged by a scavenger through
precipitation, adsorption or reaction. The optimal elimination
reaction and the best scavenging efficiency can be obtained by
separately determining the reaction conditions (temperature, pH,
chemicals immixed, etc.) necessary for the elimination of the
substances to be removed, and the conditions (temperature, pH,
scavenger, etc.) necessary for scavenging.
[0018] Sulfur, one of the substances to be removed, can be
eliminated in the form of a sulfate by precipitating and removing
it by availing of its property that its solubility in supercritical
or subcritical water varies greatly depending on temperature, or
can be scavenged by making use of the reaction between metal
sulfides and Ca or metal oxides, etc., or adsorption on
ceramics.
[0019] Vanadium can be eliminated in the form of vanadium oxide by
scavenging it by a ceramics adsorption reaction or can be scavenged
in the form of a metal vanadate by making use of the formation of a
composite oxide through a reaction with a metal oxide.
[0020] In an elimination reaction of the substances to be removed,
an alkali metal such as Na or an alkaline earth metal can be added
for accelerating the reaction. Such a metal can also act as a
material for forming a sulfate after removal of sulfur. Hydrogen
peroxide water, nitric acid or a nitrate can be used as an
oxidizing agent to change a part of the hydrocarbon into carbon
monoxide CO, and an elimination of the substances to be removed is
promoted by making use of a reaction that hydrogen produced by the
shift reaction of CO and water accelerates cleavage of the carbon
chains. A similar effect can be obtained by introducing a material,
such as formic acid, which directly provides hydrogen atoms.
[0021] According to the method of the present invention, a
scavenger is applied as a fixed bed or a fluidized bed in a
scavenging apparatus for scavenging from the fuel the substances to
be removed which was released in the reactor, and thereby a ceramic
agent is used for adsorbing calcium or vanadium oxide which may
cause simultaneously a reaction with a sulfide and generation of a
metal oxide which forms a composite oxide with vanadium or
generation of a composite oxide with vanadium. Use of this
scavenger enables scavenging of the substances to be removed and
their discharge out of the system in the form of solids.
[0022] The present invention provides a system which can reform a
heavy oil to a fuel suited for a gas turbine by the above-described
apparatus and which is also capable of determining a reforming rate
according to a fuel amount requirement of the burner by connecting
the apparatus to a fuel line of a gas turbine power generation
system. By using the fuel obtained by the heavy oil reforming
apparatus of the present invention as a fuel system for a gas
turbine power-generating plant, it is possible to remove the
harmful components in the fuel, which have previously caused a
serious environmental problem, and this makes it possible to
prevent a corrosion of the plant equipment due to heavy metals as
mentioned above and to enhance reliability of the gas turbine
equipment.
[0023] As described above, the substances to be removed, such as
sulfur and/or vanadium, can be eliminated from a heavy oil by an
action of supercritical water as a solvent and an action of a
hydrolyzing agent, and the eliminated substances are scavenged by a
scavenger, so that the whole of the hydrocarbons in a heavy oil can
be converted to a fuel for a gas turbine and can be burned. This
enables use of low-cost heavy oils as a fuel for gas turbines,
which leads to a reduction of a running cost and cuts down the
equipment cost for the environmental apparatus and measures against
corrosion of the gas turbines. Further, this realizes a reduction
of environmental equipment cost and enables a continuous operation
of the apparatus because of no ash deposition and a prevention of
corrosion to attain a significant enhancement of the plant
operating efficiency.
[0024] Other objects, features and advantages of the invention will
become apparent from the following description of the embodiments
of the invention taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a schematic sectional view of the primary portion
of the heavy oil reforming apparatus according to the present
invention.
[0026] FIG. 2 is a block diagram showing the system layout of the
heavy oil reforming apparatus according to the present
invention.
[0027] FIG. 3 is a block diagram showing a gas turbine power
generation system connected to the heavy oil reforming apparatus of
the present invention.
EXPLANATION OF REFERENCE NUMERALS
[0028] 1: mixer, 2: supercritical water, 3: heavy oil, 4: reactor,
5: connecting pipe, 6: scavenging apparatus, 7: scavenger, 8:
reformed fuel, 9: reaction assistant, 10: scavenger supply line,
11: used scavenger discharge line, 12: scavenger cleaner, 13:
removed substance (harmful component), 14: recycled scavenger, 15:
newly fed scavenger, 16: air, 17: compressor, 18: compressed air,
19: burner, 20: combustion gas, 21: gas turbine, 22: power
generator (dynamo), 23: gas turbine exhaust gas, 24: exhaust gas
heat exchanger, 25: water, 26: stack.
DETAILED DESCRIPTION OF THE INVENTION
[0029] Elimination of vanadium from a heavy oil has been confirmed
when a vanadium-containing heavy oil was mixed and reacted with
supercritical or subcritical high-temperature and high-pressure
water and then passed through a scavenger-packed bed.
[0030] More specifically, when a heavy oil containing 5 ppm of
vanadium was mixed and reacted with supercritical water having a
temperature of 450.degree. C. and a pressure of 25 MPa and then
passed through an activated carbon packed bed, it was confirmed
that the vanadium concentration of the reformed oil reduced to 2
ppm. It was also confirmed that the vanadium concentration of the
reformed oil was reduced to 0.1 ppm when a heavy oil containing 5
ppm of vanadium was mixed and reacted with subcritical water having
450.degree. C. and 20 MPa and then passed through an activated
carbon packed bed.
EXAMPLES
Example 1
[0031] FIG. 1 is a schematic sectional view of the primary portion
of the heavy oil reforming apparatus according to the present
invention. At the inlet of the apparatus is provided a mixer 1
designed to receive and mix high-temperature and high-pressure
water such as supercritical water 2 and a heavy oil 3. This water
and heavy oil are mixed by the solvent action of the supercritical
water in mixer 1, and the mixed liquid is led into a reactor 4.
Mixing of supercritical water 2 and heavy oil 3 may be effected not
only by simple joining of both fluids but can be also effected by
forming a whirling flow or by making use of impingement of the
counter flows of the two fluids for accelerating mixture.
[0032] Mixer 1 may not be provided, and super-critical water 2 and
heavy oil 3 may be directly supplied into reactor 4. In reactor 4,
there proceeds a reaction for eliminating from the hydrocarbon
compounds the harmful components, i.e. sulfur and/or vanadium in
the heavy oil under the action of supercritical water as a
hydrolyzing agent. For allowing this elimination reaction to
proceed, it is an essential condition that water assumes a
supercritical state by the time it reaches the exit of reactor 4.
In the instant example, water already brought into a supercritical
state is supplied, but it is possible to let water assume a
supercritical state by heating after the mixture of water and heavy
oil has been supplied to mixer 1 or reactor 4.
[0033] The liquid containing the harmful components eliminated from
the fuel in reactor 4 is sent to a scavenging apparatus 6 via a
connecting pipe 5. Reactor 4 may be joined directly to scavenging
apparatus 6 without connecting pipe 5. Scavenging apparatus 6 is
filled with a scavenger 7 which scavenges the substances to be
removed (harmful components). Scavenging is effected by adsorption,
reaction or precipitation of the harmful components contained in
the circulating liquid. Only the harmful components are scavenged
in scavenging apparatus 6, and almost whole of the hydrocarbons
which are to form fuel can be fed to an apparatus in subsequent
stage as reformed fuel.
[0034] Scavenger 7 may be provided in scavenging apparatus 6 as a
fixed bed by a grating-like fixture. It is also possible to apply
granular scavenger and let it stay in the apparatus as a fluidized
bed by regulating the grain size so that it can produce a greater
terminal velocity than the linear velocity of the liquid. Further,
the scavenger may be molded into a plate or a honeycomb structure
allowing the liquid to pass through the voids therein.
[0035] The scavenging capacity of scavenger 7 may reach saturation
as a result of continuous scavenging of the harmful components, so
a system for taking out such used scavenger 7 from scavenging
apparatus 6 or a system for giving new supply of scavenger may be
provided. Also, plural sets of scavenging apparatus 6 may be
provided for each reactor 4 and designed so that they can be
operated in turn successively, or that the operation of part of the
plural sets of scavenging apparatus may be stopped on passage of a
predetermined period of time. It is also possible to adopt a layout
and an operating method that allow change of the scavenger in the
scavenging apparatus to which the supply of fuel was suspended. The
fuel from which the harmful components were eliminated by
scavenging apparatus 6 is discharged as reformed fuel 8.
[0036] In order to provide for ingress of the scavenger in the form
of granules in the reformed fuel, a filter or cyclone for excluding
the granules may be set on the exist side of the scavenging
apparatus. In this embodiment of the invention, scavenger 7 is not
limited to one type; it is expedient to properly mix other types of
scavenger according to the purpose of use of the fuel, for example
Ca compounds which react with sulfur atoms, metal oxides which
react with vanadium oxides, and alumina, silica or such which
adsorb metal oxides or serve as a precipitation bed for sulfates.
Also, for obtaining the optimal temperature for the type of
scavenger used by changing the temperature conditions for the
reactor and the scavenging apparatus, a heater or a heat exchanger
may be provided in connecting pipe 5 or scavenging apparatus 6.
Example 2
[0037] FIG. 2 is a block diagram showing the layout of the heavy
oil reforming apparatus according to the present invention. In this
example, a reaction assistant 9 which functions to accelerate the
harmful component elimination reaction in reactor 4 is applied in
addition to supercritical water 2 and heavy oil 3 in mixer 1.
Reaction assistant 9 is a material selected from alkali metal or
alkaline earth metal which acts to eliminate sulfur, a harmful
component, in the form of a sulfate, hydrogen peroxide solution
which accelerates the hydrolytic reaction, nitrate, formic acid and
the like, or a mixture of such materials.
[0038] Addition of such a reaction assistant 9 is intended to
elevate the harmful component elimination efficiency in reactor 4.
As mentioned in Example 1, supercritical water 2, heavy oil 3 and
reaction assistant 9 may be directly supplied to and mixed in
reactor 4 without providing a mixer. Also, reaction assistant 9 may
be either mixed in the system or may be previously contained in
supercritical water 2 or heavy oil 3 before they are supplied to
the system. Since the intended reaction proceeds if supercritical
water 2 takes a supercritical state before it reaches the exit of
reactor 4, it may be supplied in the state of water in mixer 1 or
at the inlet of reactor 4 and heated in reactor 4 to let it take a
supercritical state. It is of course possible to mix reaction
assistant 9 in water before supplied to the apparatus, and this is
recommendable when the reaction assistant used is of a
water-soluble type.
[0039] In the instant example, only one reactor 4 is provided, but
it is effective to provide plural reactors and arrange them so as
to provide a residence time suited for the reaction. In scavenging
apparatus 6, the harmful components are scavenged by scavenger 7.
In order to prevent the scavenging capacity of the scavenger 7 from
reaching saturation, there are provided a system 11 for discharging
the used scavenger and a system 10 for introducing a fresh supply
of scavenger. The discharged used scavenger is forwarded to a
scavenger cleaner 12 where the used scavenger is subjected to the
cleaning and reacting operations to eliminate the harmful
components 13, and the regenerated scavenger is recycled to the
scavenger supply system as indicated at 14.
[0040] For supplementing the scavenging capacity lowered by the
reaction, a new supply of scavenger 15 is added to the recycled
scavenger and the mixture is returned to scavenging apparatus 6.
This arrangement is effective when the granules stay in a fluidized
state. In case scavenger 7 is applied as a fixed bed or molded into
a plate or a honeycomb structure, it can not be easily taken out of
the system. In such a case, plural sets of scavenging apparatus 6
may be provided and arranged so that change or renewal of scavenger
7 can be effected as desired by stopping the operation of part of
the apparatus in turn. It is also effective to provide plural sets
of scavenging apparatus 6 and arrange them so as to provide a
residence time necessary for the supplementing work.
Example 3
[0041] FIG. 3 is a block diagram showing an example of the gas
turbine power generation system using the heavy oil reforming
apparatus according to the present invention. In Examples 1 and 2,
the reformed fuel 8 may be kept in storage or transported for use
in a power plant, but in the instant example, the reformed fuel is
immediately burned by a burner in the power generation system. Like
in Example 2, a reaction accelerator 9 which accelerates the target
substance elimination reaction in reactor 4 is mixed in addition to
supercritical water 2 and heavy oil 3 in mixer 1.
[0042] Reaction accelerator 9 is a material selected from alkali
metal or alkaline earth metal which eliminates sulfur, which is a
substance to be removed, in the form of a sulfate, hydrogen
peroxide solution which accelerates the hydrolytic reaction, and
other materials such as nitrate and formic acid, or a mixture of
such materials. The substances to be removed are eliminated from
oil in reactor 4 and scavenged by scavenger 7 in scavenging
apparatus 6. In order to prevent the scavenging capacity of
scavenger 7 from reaching saturation, there are provided a system
11 for discharging the used scavenger and a system 10 for feeding a
new supply of scavenger. The discharged used scavenger is forwarded
to a scavenger cleaner 12 where the used scavenger is subjected to
the cleaning and reacting operations to eliminate the substances to
be removed 13, and the regenerated scavenger is recycled to the
scavenger supply system as indicated at 14.
[0043] For supplementing the scavenging capacity lowered by the
reaction, a new supply of scavenger 15 is added to the recycled
scavenger and the mixture is returned to scavenging apparatus 6. In
this example, there is provided only one set each of reactor 4 and
scavenging apparatus 6, but it is effective to provide plural sets
of both reactor and scavenging apparatus so that a residence time
suited for the reaction and scavenging will be provided according
to the amount of fuel supplied to gas turbine burner 19. The thus
produced reformed fuel 8 is burned by burner 19 with air 18
compressed by compressor 17, and gas turbine 21 is driven by
combustion gas 20 to generate power by dynamo 22 connected to gas
turbine 21. Exhaust gas 23 from the gas turbine is led into exhaust
gas heat exchanger 24 where heat is transferred from gas to water
25 to generate supercritical water 2. Utilization of exhaust gas
heat contributes to the improvement of system working efficiency.
As in the conventional composite gas turbine power generation
system, the exhaust gas recovering boilers may be provided in front
and in the rear of exhaust gas heat exchanger 24 and a steam
turbine may be driven by the produced steam to generate electric
power. A denitrating apparatus may be provided for removing the
nitrogen oxides produced by combustion. Since sulfur in the heavy
oil is eliminated by scavenging apparatus 6, there is no need of
providing a desulfurizing apparatus nor any requirement of
expenditure for the construction of new environmental equipment
which is otherwise required in use of heavy oils.
[0044] Further, in the construction of this embodiment, since
vanadium in the heavy oil is removed by scavenging apparatus 6,
there is no fear of high-temperature corrosion of the gas turbine,
which makes it unnecessary to add an additive, such as magnesium,
for producing a composite oxide with vanadium. Consequently,
deposition of metal oxide ash on the turbine impeller blades is
prevented, and a continuous operation of the system with the same
degree of efficiency as the gas turbine system using light oil fuel
is made possible, so that an improvement of plant working
efficiency and high-efficiency power generation can be
realized.
[0045] Operation of the gas turbine is explained here. At the
start, the gas turbine is driven by an external motive power such
as produced by a starting motor, and compressed air 18 supplied
from compressor 17 and fuel are mixed and ignited by burner 19.
After ignition, the combustion gas 20 generated by burner 19, i.e.
heat energy, is converted to a rotating energy by turbine 21, and
with rise of the flow rate of fuel to burner 19, the gas turbine is
increased in speed and proceeds into self-supporting operation.
Then, after the gas turbine reached the no-load rated rotational
speed, dynamo 22 is operated to generate power.
[0046] In the instant embodiment, supercritical water 2 is
generated by utilizing the heat produced by exhaust gas heat
exchanger 24, but it is also effective to provide a starting boiler
beside heat exchanger 24 and produce supercritical water 2 by
utilizing its heat. In the gas turbine, after application of load,
the flow rate of reformed fuel 8 supplied to burner 19 is increased
(controlled) by a flow rate control valve disposed on the upstream
side of the burner and on the downstream side of the reforming
apparatus, and the load is increased with the rise of gas
temperature at the inlet of gas turbine 21 and the increase of flow
rate of combustion gas 21 until the rated load is finally reached.
During this period, in mixer 1 where fuel is produced, the mixing
ratio of heavy oil 3 and supercritical water 2 is adjusted to form
a composition necessary for providing stabilized combustion at
burner 19.
[0047] As seen from the above, by structuring a power plant
combining the above-described heavy oil reforming apparatus of the
present invention and a gas turbine, it is possible to solve the
problems, such as corrosion of gas turbine equipment, which would
arise from the oxidizing reactions of impurities and which have
been a plaguey problem of the conventional heavy oil-fired burners,
and to improve reliability of the equipment.
EFFECTS OF THE INVENTION
[0048] According to the present invention, there are provided a
heavy oil reforming method which reforms a heavy oil to give a fuel
suitable for a gas turbine, eliminates only the harmful components
corrosive to the gas turbine from a heavy oil, and enables almost
all the hydrocarbons in the heavy oil to be used in gas turbine
combustion, and an apparatus therefor. Also, as the apparatus of
the present invention can be applied with no need of extending the
environmental protection equipment or taking specific measures
against corrosion of the gas turbine by use of a heavy oil reduced
in content of sulfur and vanadium which cause corrosion in
combustion, it is possible to realize a gas turbine power
generation system which is low in both of equipment cost and
running cost.
[0049] It should be further understood by those skilled in the art
that although the foregoing description has been made on
embodiments of the invention, the invention is not limited thereto
and various changes and modifications may be made without departing
from the spirit of the invention and the scope of the appended
claims.
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