U.S. patent application number 14/488788 was filed with the patent office on 2015-01-01 for combined cycle power plant.
The applicant listed for this patent is ALSTOM Technology Ltd. Invention is credited to Gian Luigi Agostinelli, Richard CARRONI, Enrico Conte, Joerg Dietzmann, Alvin Limoa, Tjiptady Nugroho, David Olsson, Camille Pedretti.
Application Number | 20150000249 14/488788 |
Document ID | / |
Family ID | 47913435 |
Filed Date | 2015-01-01 |
United States Patent
Application |
20150000249 |
Kind Code |
A1 |
CARRONI; Richard ; et
al. |
January 1, 2015 |
COMBINED CYCLE POWER PLANT
Abstract
The invention relates to a combined cycle power plant that
includes, a gas turbine plant, a heat recovery steam generator
heated by hot waste gases of a gas turbine plant, and a steam
turbine plant driven by the steam produced, and a waste gas
purification plant, arranged downstream of the heat recovery steam
generator in which carbon oxides in the waste gases can be absorbed
by an absorber fluid, which is subsequently regenerated at an
elevated temperature in a regenerating section while giving up the
carbon oxides for supplying to a storage. The regenerating section
has a heater for maintaining a necessary elevated temperature for
regeneration. The heater operates with steam from the heat recovery
steam generator or from the steam turbine plant. The steam
condenses and the resulting hot condensate can be supplied to a
flash boiler where it, at low pressure, immediately at least
partially evaporates. This steam can be supplied to an appropriate
stage of the steam turbine plant according to the steam
pressure.
Inventors: |
CARRONI; Richard;
(Niederrohrdorf, CH) ; Limoa; Alvin; (Neuenhof,
CH) ; Olsson; David; (Nussbaumen, CH) ;
Dietzmann; Joerg; (Baden, CH) ; Pedretti;
Camille; (Wettingen, CH) ; Nugroho; Tjiptady;
(Fislisbach, CH) ; Conte; Enrico; (Zollikerberg,
CH) ; Agostinelli; Gian Luigi; (Zuerich, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ALSTOM Technology Ltd |
Baden |
|
CH |
|
|
Family ID: |
47913435 |
Appl. No.: |
14/488788 |
Filed: |
September 17, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2013/055881 |
Mar 21, 2013 |
|
|
|
14488788 |
|
|
|
|
Current U.S.
Class: |
60/39.182 |
Current CPC
Class: |
B01D 53/62 20130101;
F01K 23/08 20130101; B01D 2252/204 20130101; Y02E 20/18 20130101;
F01K 23/06 20130101; Y02E 20/32 20130101; F01K 13/006 20130101;
B01D 2257/504 20130101; Y02C 10/04 20130101; Y02E 20/185 20130101;
F02C 6/18 20130101; Y02C 10/06 20130101; Y02E 20/16 20130101; Y02E
20/326 20130101; B01D 53/1475 20130101; Y02C 20/40 20200801; F01K
23/10 20130101 |
Class at
Publication: |
60/39.182 |
International
Class: |
F01K 23/10 20060101
F01K023/10; F01K 13/00 20060101 F01K013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 21, 2012 |
EP |
12160585.1 |
Sep 25, 2012 |
EP |
12185806.2 |
Claims
1. A combined cycle power plant (CCPP) comprising, a gas turbine
plant, a heat recovery steam generator through which hot waste
gases from the gas turbine plant flow, a steam turbine plant driven
by steam from the heat recovery steam generator, and a waste gas
purification plant, arranged downstream of the heat recovery steam
generator, having an absorbing section in which carbon dioxide in
the waste gases is absorbed by an absorber fluid, whereby the waste
gas purification plant comprises a regeneration section which is
supplied with the absorber fluid loaded with carbon dioxide,
whereby the absorber fluid can be regenerated at an elevated
temperature while giving up the carbon dioxide for supplying to a
storage, and whereby the regenerated absorber fluid is supplied
back into the absorbing section for absorbing the carbon dioxide in
the waste gases, whereby the regeneration section comprises a
heater which is heatable with the steam from the heat recovery
steam generator or from the steam turbine plant, whereby the
supplied steam condenses in or at the heater and the resulting hot
condensate is supplied to at least one evaporator, where it is at
least partially evaporated to steam and whereby this steam is
introduced into a stage of the steam turbine plant, in particular
into an intermediate stage of the low pressure turbine of the steam
turbine plant.
2. The combined cycle power plant according to claim 1, further
comprising a heat exchanger is arranged between the absorber
section and the regeneration section, whereby the absorber fluid
from the regeneration section being led back into the absorbing
section, and the absorber fluid from the absorbing section being
supplied to the regeneration section through the heat
exchanger.
3. The combined cycle power plant according to claim 1, wherein the
thermal energy extracted from the absorbing section is used for
preheating fuel for the gas turbine plant or for preheating feed
water for the steam turbine plant.
4. The combined cycle power plant according to claim 1, wherein a
part of the steam generated by the at least one evaporator is added
to the steam supplied to the heater of the regeneration
section.
5. The combined cycle power plant according to claim 1, wherein the
steam generated by the at least one evaporator is superheated in a
heater of the heat recovery steam generator and then supplied to a
middle stage of the low pressure turbine of the steam turbine
plant.
6. The combined cycle power plant according to claim 1, wherein the
steam turbine plant comprises a high pressure steam turbine, a
medium pressure steam turbine and a low pressure steam turbine,
whereby steam is taken from a point between the outlet of the
medium pressure steam turbine and the inlet of the low pressure
steam turbine for heating the heater of the regeneration
section.
7. The combined cycle power plant according to claim 1, wherein the
condensate is supplied to a cascade of flash boilers, whereby
pressurized water or condensate from a first flash boiler is
supplied to a second flash boiler which has a lower inner pressure
relative to the first flash boiler, so that the pressurized water
or condensate from the first flash boiler can at least partially
evaporate, whereby the steam produced by the flash boilers is
supplied to one or more stages of the steam turbine plant, in
particular to the low pressure steam turbine, corresponding to
their different pressures.
8. The combined cycle power plant according to claim 7, wherein the
steam from the at least one flash boiler is superheated, e.g. with
the heat recovery steam generator, before being introduced into a
stage of the steam turbine plant.
9. The combined cycle power plant according to claim 7, wherein the
steam from the at least one flash boiler is superheated by the
steam, coming from the outlet of the high pressure steam turbine of
the steam turbine plant.
10. The combined cycle power plant according to claim 1, wherein
the remaining condensate from the at least one evaporator is
supplied to the feed water tank of the steam turbine plant.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to PCT/EP2013/055881 filed
Mar. 21, 2013, which claims priority to European application
12160585.1 filed Mar. 21, 2012 and European application 12185806.2
filed Sep. 25, 2012, all of which are hereby incorporated in their
entireties.
TECHNICAL FIELD
[0002] The present invention relates to a combined cycle power
plant (CCPP) comprising a gas turbine plant, a heat recovery steam
generator (HRSG) heated with hot exhaust gases from the gas turbine
plant, and a steam turbine plant driven by the generated steam.
BACKGROUND
[0003] Such a CCPP is shown in U.S. Pat. No. 5,839,269. In this
known CCPP a steam turbine plant is provided with a high pressure
turbine, a medium pressure turbine and a low pressure turbine,
whereby high pressure and medium pressure steam is produced in the
steam generator for driving the high pressure or medium pressure
turbine, and the steam expanded in the medium pressure turbine is
used to drive the low pressure turbine. In the CCPP of U.S. Pat.
No. 5,839,269 it is also provided that steam with reduced low
pressure can be channeled off from a sufficiently hot feed water
tank of the steam generator and fed into a medium stage of the low
pressure turbine through appropriate steam inlets.
[0004] In addition U.S. Pat. No. 5,839,269 discloses a range of
measures for optimizing the design of gas turbine plants and for
optimizing the operation of gas turbines.
[0005] Gas turbine plants and other large combustion plants are
typically operated with fuels based on hydrocarbons. This
inevitably generates carbon oxides during operation, especially
carbon dioxide, which is a green house gas and harmful to the
environment, and should therefore be separated from the waste gases
of the gas turbine plant. In principle, known waste gas
purification plants can be used which are arranged downstream of
the respective combustion process and which have an absorbing
section and a regenerating section. Carbon dioxide which is carried
along within the absorbing section, through which the particular
waste gases are flowing, can be absorbed at relatively low
temperature using an amine-H.sub.2O-system with the formation of a
relatively concentrated amine carbonate solution. The concentrated
amine carbonate solution can be subsequently converted in a
regeneration section at high temperature into a relatively weak
concentration amine-carbonate-solution, whereby carbon dioxide is
released and led away and subsequently collected and stored. In
lieu of such amine systems other waste gas purification systems,
for example systems using chilled ammonia, can also be used.
[0006] From US 2011/0314815 A1 it is generally known to equip a
CCPP as described above with a downstream waste gas purification
plant. in US 2011/0314815 A1 it is shown that a waste gas
purification plant with relatively small capacity can be
sufficient, if the gas turbine plant is operated with exhaust gas
recirculation in such a way that during combustion substantially
only completely oxidized hydrocarbons, that is, carbon dioxide and
water (and N.sub.2) remain. Otherwise, there is no indication
towards an optimal integration of the waste gas purification plant
into a CCPP.
SUMMARY
[0007] The purpose of the invention is thereby to connect a CCPP
with a waste gas purification plant in an optimized way to supply
the necessary thermal energy for heating the regeneration section
of the purification plant and to use the residual heat for
increasing the performance of the steam turbine plant.
[0008] In particular, according to the invention, a waste gas
purification plant is provided downstream of the gas turbine plant
and the heat recovery steam generation plant, the gas purification
plant comprising an absorbing section and a regenerating section,
whereby inside the absorbing section, through which the waste gases
flow, carbon dioxide which is carried in the waste gases is
absorbed by an amine-H.sub.2O-system at relatively low temperature
forming (relatively) high concentrations of amine carbonate
solution, and whereby the concentrated amine carbonate solution is
converted into a relatively weak amine carbonate solution in the
regeneration section at an elevated temperature giving off carbon
dioxide which is led away, whereby the regeneration section can be
heated with steam, and the relatively weak amine carbonate solution
generated in the regeneration section having an elevated
temperature can be supplied via a heat exchanger back into the
absorbing section for reuse, and thermal energy can be exchanged in
the heat exchanger between the relatively weak concentration of
amine carbonate solution and the relatively high concentration of
amine carbonate solution being supplied to the regeneration
section.
[0009] According to a first aspect of the invention the heat for
the regeneration of the amine solution is introduced into the
regeneration section by way of steam from the steam turbine and/or
the steam generator, and the heat from the regenerated amine
solution, having an elevated temperature, is used for preheating
the high concentration amine carbonate solution led away from the
absorbing section. The thermal energy required for regeneration of
the amine solution can thereby be substantially reduced.
[0010] According to a preferred embodiment, the regeneration
section is heated with saturated steam at a specified temperature.
It is advantageous that the temperature level is only dependent on
the steam pressure, so that the desired temperature can be
regulated with the steam pressure.
[0011] In the case of a steam turbine plant with a high pressure
steam turbine, a medium pressure steam turbine and a low pressure
steam turbine, the steam for heating the regeneration section can
be taken from the connection between the outlet of the medium
pressure turbine and the inlet of the low pressure turbine.
[0012] According to an advantageous embodiment of the invention,
the hot condensate generated from heating the regeneration section
can be supplied to an evaporator of the heat recovery steam
generator in order to produce additional steam with low pressure,
the steam can then be supplied to a stage of the low pressure
turbine, whereby this steam can, if necessary, be channeled through
a superheater of the steam generator before being introduced into
the low pressure turbine, in order to increase its power
output.
[0013] Advantageously, the thermal energy, which may need to be
conducted away from the absorbing section, can be used to preheat
the feed water for the steam generator.
[0014] The steam circuits therefore only need to be slightly
modified, according to the invention, to supply the necessary
thermal energy for the waste gas purification plant and/or to use
resulting residual heat for increasing the performance of the steam
turbine plant, i.e. the hot condensate is used in a new, additional
pressure level (compared to the standard water-steam cycle.
[0015] According to a particularly advantageous embodiment of the
invention the regeneration of the amine solution in the
regeneration section can be carried out at a temperature of
126.degree. C. as opposed to a possible process temperature of
about 145.degree. C., whereby the separation of the carbon dioxide
out of the high concentration amine carbonate solution supplied to
the regeneration section happens at a less than optimal process
temperature. This is accepted here because the necessary thermal
energy for heating the regeneration section is thereby
disproportionally reduced, so that the performance of the CCPP and
its efficiency can be substantially increased. As a result, only a
relatively small loss of performance must be tolerated compared to
a CCPP without downstream waste gas purification.
[0016] According to another aspect of the invention the hot
condensate or pressurized water is supplied to at least one flash
evaporator and allowed at least partly to evaporate there at low
pressure so that additional steam is released for operating the
steam turbine plant, in particular for the low pressure steam
turbine of the steam turbine plant.
[0017] Usable steam for operating the low pressure turbine of the
steam turbine plant is produced with little effort by introducing
hot condensate or pressurized water into the at least one flash
boiler, where it boils due to a fast reduction in pressure and
evaporates. The physical effect is thereby exploited whereby the
boiling point of a liquid is dependent on pressure, and accordingly
a hot liquid starts to boil suddenly when it is introduced into a
space having low pressure and therefore at least partially
evaporates.
[0018] According to a preferred embodiment of the invention, where
appropriate, a series of flash boilers can be provided, whereby
pressurized water or condensate from a first flash boiler is
supplied to a second flash boiler which has a lower inner pressure
compared to the first flash boiler, so that the pressurized water
or condensate, coming out of the first flash boiler, can at least
partially evaporate here. If necessary, further flash boilers can
be arranged in a cascade. The flash boilers in the flash boiler
cascade thereby produce steam with accordingly different pressure
levels, whereby the steam of each flash boiler is supplied to an
appropriate stage of the turbine, in particular to the low pressure
turbine of the steam turbine plant.
[0019] The steam coming from a flash boiler can, if necessary, be
superheated with the heat recovery steam generator plant of the
CCPP in order to drive the respective turbine section more
effectively.
[0020] Preferred features of the invention can be found in the
claims and in the following description of the drawings by way of
which particularly preferred embodiments of the invention are
described in more detail.
[0021] Protection is not only claimed for the indicated or shown
combination of features but also for any combination of the shown
or indicated individual features.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The drawings show in:
[0023] FIG. 1 a highly schematized representation of a CCPP
according to the invention,
[0024] FIG. 2 a schematized representation of a waste gas
purification plant according to the invention,
[0025] FIG. 3 a representation of an advantageous connection of the
regeneration section of the waste gas purification plant to a CCPP
or its steam generator or its low pressure steam turbine of the
steam turbine plant
[0026] FIG. 4 a schematized representations for the use of a hot
condensate or pressurized water from the power plant or waste gas
purification plant, and
[0027] FIG. 5 an advantageous variation of the arrangement shown in
FIG. 3.
DETAILED DESCRIPTION
[0028] According to FIG. 1 the CCPP according to the invention
comprises a gas turbine plant 1, which can have a generally known
construction, for example as in the above mentioned U.S. Pat. No.
5,839,269, and having a compressor 11, at least one combustion
chamber 12 and a gas turbine 13. The hot waste gases 100 of the gas
turbine plant 1 then flow through a heat recovery steam generator
2. Arranged downstream of the heat recovery steam generator 2 is a
waste gas purification plant 4, which is described below. The steam
produced in the heat recovery steam generator 2 drives a steam
turbine plant 5. The gas turbine plant 1 and the steam turbine
plant 5 can drive generators 3 or the like respectively, whereby it
is possible in principle to couple the rotor shafts R of the gas
turbine plant 1 with those of the steam turbine plant 5 and use a
common generator 3.
[0029] For driving the steam turbine plant 5 a steam circuit can be
provided as described in the following:
[0030] Water is fed by a pump 7 from a feed water tank 6 into a
heater 8, which is arranged inside of a heat recovery steam
generator 2 in the waste gas path. At the outlet of the heater 8
there is high pressure water with, for example, a pressure of 160
bar and a temperature of 300.degree. C. In a tube register 9
downstream of the heater 8 the high pressure water is evaporated
and superheated, so that high pressure steam is available at the
outlet of the tube register 9. This superheated, high pressure
steam is supplied to a high pressure steam turbine 51 of the steam
turbine plant 5, whereby the high pressure steam expands inside the
high pressure turbine 51. The steam expanded in this way, CRH (Cold
Reheat), is subsequently supplied through a further tube register
10, so that this steam is reheated. The steam from the tube
register 10 is supplied to a medium pressure turbine 52 of the
steam turbine plant 5, whereby the steam expands in the medium
pressure turbine 52 so that there is low pressure steam downstream
of it, which, if necessary, can be further heated in a tube
register (not shown) and supplied to a low pressure turbine 53 of
the steam turbine plant 5. The steam expanded in the low pressure
turbine 53 subsequently flows into an air- or water-cooled
condenser 109. The condensate produced there is then supplied by a
pump 111 back to the feed water tank 6.
[0031] According to FIG. 2, the waste gas purification plant 4
comprises an absorbing section 41 through which the waste gas
flows, and a regeneration section 42 in order to regenerate the
absorbing medium from section 41 and to supply it back to the
absorbing section 41. At the outlet of the absorbing section 41
there are waste gases 1000 free of carbon oxides.
[0032] Inside the absorbing section 41 the waste gases 100 flow
through a bath of water and amine solution, whereby the carbon
dioxide in the waste gases 100 is bonded by the water to form
carbonic acid, which with the amines then forms a relatively high
concentration of amine carbonate solution. This relatively high
concentration of amine carbonate solution is supplied to the
regeneration section 42 by a pump 113. Inside the regeneration
section 42 a high temperature is maintained, for example a
temperature from about 120.degree. to 145.degree. C., at which the
relatively high concentration of amine carbonate solution is
converted into a relatively weak concentration of amine carbonate
solution, giving off carbon dioxide in the process, whereby the
carbon dioxide is supplied by a compressor 114 to a store or the
like (not shown).
[0033] The temperature necessary for the regeneration process in
the regeneration section 42 can be maintained by circulating the
relatively weak concentration of amine carbonate solution, produced
in the regeneration section 42, in a circuit through a heater 115,
which is itself heated with steam as described below.
[0034] The relatively weak concentration of amine carbonate
solution is supplied back to the absorbing section 41 by a pump
116, whereby on returning the solution flows through a heat
exchanger 112 through which the relatively high concentration of
amine carbonate solution being supplied to the regeneration section
42 also flows (in opposite directions), so that the high
concentration of amine carbonate solution supplied to the
regeneration section 42 is pre-heated and the heater 115 requires a
relatively low thermal input for maintaining the necessary
temperature for the regeneration process.
[0035] The heater 115 of the regeneration section 42 is preferably
heated with steam, in particular saturated steam, which can be
diverted off at point A in FIG. 1 in the steam path between the
medium pressure steam turbine 52 and the low pressure steam turbine
53 of the steam turbine plant 5. This channeled off steam condenses
at or in the heater 115 whilst giving up heat to the relatively low
concentration amine carbonate solution. The thereby generated
condensate K, the temperature of which is around the operating
temperature of the regeneration section 42, i.e. at a temperature
between about 120.degree. C. and 145.degree. C., can then be
supplied according to FIG. 3 to an evaporator 118 and therein
heated with heat from the heat recovery steam generator 2. The
steam generated there, the pressure of which is below the pressure
of the steam supplied to the inlet of the low pressure steam
turbine, can be subsequently superheated and supplied via
appropriate steam inlets to an intermediate stage of the low
pressure steam turbine 53.
[0036] Alternatively, the steam produced by the evaporator 118 can
be supplied to the heater 115 together with the steam channeled off
from point A, preferably superheated. The dotted line in FIG. 3
shows such option.
[0037] Alternatively, the condensate K from the heater 115 can also
be introduced into the feed water tank 6 so that, on the one hand,
the feed water is accordingly heated.
[0038] As a result the condensate K from the heater 115 is used for
producing steam having a very low pressure for introducing into an
intermediate stage of the low pressure steam turbine 53. The waste
gas purification plant is therefore used to generate a fourth steam
pressure level, in addition to the steam pressure levels for the
high, middle, and low pressure steam turbines of the steam turbine
plant 5. The steam turbine plant 5 and the heat recovery steam
generator 2 are only slightly modified by the waste gas
purification plant 4.
[0039] It has proved advantageously to operate the regeneration
section 42 of the waste gas purification plant 4 at a relatively
low temperature, which is actually suboptimal for the regeneration
process. The thermal energy requirement of the heater 115 is
thereby disproportionally reduced, with the result that the loss of
performance of the CCPP, due to the necessary removal of thermal
energy during the operation of the waste gas purification plant 4,
is kept low.
[0040] The absorbing section 41 of the waste gas purification
plant, through which the hot waste gases 100 flow, must be cooled
in order to maintain the necessary low temperature for the
absorption process. This temperature is about 40.degree. C. in case
of the amine system, and about 5.degree. C. in case of the chilled
ammonia process.
[0041] According to an embodiment, shown in FIG. 4, the hot
condensate K from heater 115 is supplied by a pump 116 to the inlet
of a flash boiler 117, whereby a regulating valve 118 is arranged
at the inlet of the flash boiler 117 in order to maintain a
pressure in the line between the flash boiler 117 and the pump 116,
whereby the pressure is above the boiling pressure of water at the
prevailing temperature of the condensate K. In the flash boiler 117
there is a lower pressure compared to the pressure in the line
between the pump 116 and the flash boiler 117, so that the
condensate K introduced into the flash boiler 117, to a greater or
less extent, immediately evaporates (flashes to steam). The very
low pressure steam produced, the pressure of which is below the
steam pressure at A in the steam path between the medium pressure
turbine and the low pressure turbine, can now be supplied to an
intermediate stage of the low pressure turbine 53. By increasing
the pressure of the hot condensate K using pump 116, the pressure
and the quantity of the flashed steam, produced in the boiler 117,
can be increased.
[0042] According to a preferred variation of this embodiment the
very low pressure steam from the flash boiler 117 can be
superheated in a heater 119 before it is introduced into the low
pressure turbine 53. The heater 119 can itself be heated with steam
from the outlet of the high pressure turbine (CRH) or preferably by
flue gas in the heat recovery steam generator (HRSG). In principle
any other heat source could also be used.
[0043] According to another embodiment of the invention, as shown
in FIG. 5, in place of a single flash boiler 117, there can be a
cascade of flash boilers 117, 117', 117'', whereby the condensate
coming from each flash boiler 117, 117' is supplied to a subsequent
flash boiler 117', 117'' through a further regulating valve 118',
118'', whereby the pressure in the subsequent flash boiler 117',
117'' is lower than the pressure in the preceding flash boiler 117,
117', so that the condensate supplied to it partially evaporates
quickly. For example, the cascade may comprise three flash boilers
117, 117', 117'', as shown in FIG. 5.
[0044] As mentioned above, the pump 116 in FIGS. 4 and 5 can be
used for increasing the hot condensate (K) pressure, so as to
increase the pressure and quantity of the flashed steam.
[0045] In this way, steam flows having subsequently decreasing
pressures can be directed from the flash boilers of the flash
boiler cascade 117, 117', 117'' and be supplied to appropriate
different stages of the low pressure steam turbine 53.
[0046] In this embodiment the steam flows, supplied to the low
pressure steam turbine, can also be superheated in appropriate
heaters 119, before they are introduced into the low pressure steam
turbine 53. The heater 119 may be heated by steam from any suitable
source.
[0047] This embodiment is based on the general idea that condensed
water exiting at relatively high temperature can be (partially)
evaporated in flash boilers at low pressure, and the steam produced
can be used for driving the steam turbine.
* * * * *