U.S. patent application number 15/157269 was filed with the patent office on 2017-08-24 for process for retrofitting an industrial gas turbine engine for increased power and efficiency.
The applicant listed for this patent is Joseph D. Brostmeyer, Justin T. Cejka, Russell B. Jones, John E. Ryznic. Invention is credited to Joseph D. Brostmeyer, Justin T. Cejka, Russell B. Jones, John E. Ryznic.
Application Number | 20170241336 15/157269 |
Document ID | / |
Family ID | 59629720 |
Filed Date | 2017-08-24 |
United States Patent
Application |
20170241336 |
Kind Code |
A1 |
Jones; Russell B. ; et
al. |
August 24, 2017 |
Process for retrofitting an industrial gas turbine engine for
increased power and efficiency
Abstract
A process for retrofitting an industrial gas turbine engine of a
power plant where an old industrial engine with a high spool has a
new low spool with a low pressure turbine that drives a low
pressure compressor using exhaust gas from the high pressure
turbine, and where the new low pressure compressor delivers
compressed air through a new compressed air line to the high
pressure compressor through a new inlet added to the high pressure
compressor. The old electric generator is replaced with a new
generator having around twice the electrical power production. One
or more stages of vanes and blades are removed from the high
pressure compressor to optimally match a pressure ratio split.
Closed loop cooling of one or more new stages of vanes and blades
in the high pressure turbine is added and the spent cooling air is
discharged into the combustor.
Inventors: |
Jones; Russell B.; (North
Palm Beach, FL) ; Brostmeyer; Joseph D.; (Jupiter,
FL) ; Cejka; Justin T.; (Palm Beach Gardens, FL)
; Ryznic; John E.; (Jupiter, FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Jones; Russell B.
Brostmeyer; Joseph D.
Cejka; Justin T.
Ryznic; John E. |
North Palm Beach
Jupiter
Palm Beach Gardens
Jupiter |
FL
FL
FL
FL |
US
US
US
US |
|
|
Family ID: |
59629720 |
Appl. No.: |
15/157269 |
Filed: |
May 17, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62299248 |
Feb 24, 2016 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01D 17/14 20130101;
F05D 2230/80 20130101; F05D 2260/211 20130101; F02C 3/00 20130101;
F02C 9/22 20130101; F05D 2220/32 20130101; F02C 3/13 20130101; F05D
2220/76 20130101; F01D 15/10 20130101; F02C 6/00 20130101; F05D
2260/202 20130101; F02C 9/18 20130101; F02C 7/18 20130101; F05D
2240/35 20130101 |
International
Class: |
F02C 3/13 20060101
F02C003/13; F01D 17/14 20060101 F01D017/14; F02C 9/22 20060101
F02C009/22; F01D 15/10 20060101 F01D015/10; F02C 7/18 20060101
F02C007/18; F02C 9/18 20060101 F02C009/18 |
Goverment Interests
GOVERNMENT LICENSE RIGHTS
[0002] This invention was made with Government support under
contract number DE-FE0023975 awarded by Department of Energy. The
Government has certain rights in the invention.
Claims
1. A process for retrofitting an industrial gas turbine engine of a
power plant, the industrial gas turbine engine having a main
compressor driven by a main turbine and an electric generator
either driven by the main compressor or by a power turbine driven
by the main turbine, the process comprising the steps of: adding a
new inlet to the main compressor capable of receiving a greater air
flow; adding a low spool with a low pressure turbine driving an low
pressure compressor to the main turbine such that the low pressure
turbine is driven by exhaust from the main turbine; adding a
variable inlet guide vane assembly to an inlet side of the low
pressure turbine; adding a compressed air line connecting the low
pressure compressor to the new inlet of the main compressor such
that compressed air from the low pressure compressor flows into the
main compressor; and, replacing the electric generator with a new
electric generator that has around twice the electrical power
production.
2. The process for retrofitting an industrial gas turbine engine of
a power plant of claim 1, and further comprising the steps of:
removing at least one stage of rotor blades and stator vanes from
the main compressor to optimally match a pressure ratio split
between the low pressure compressor and the main compressor.
3. The process for retrofitting an industrial gas turbine engine of
a power plant of claim 1, and further comprising the steps of:
removing the old electric generator from the power turbine; adding
a low pressure compressor to be driven by the power turbine; adding
a variable inlet guide vane assembly to an inlet side of the power
turbine; adding a compressed air line connecting the low pressure
compressor to the new inlet of the main compressor such that
compressed air from the low pressure compressor flows into the main
compressor; and, adding a new electric generator having around
twice the electrical power production of the old generator to be
driven by the high pressure compressor shaft.
4. The process for retrofitting an industrial gas turbine engine of
a power plant of claim 3, and further comprising the steps of:
removing at least one stage of rotor blades and stator vanes from
the main compressor to optimally match a pressure ratio split
between the low pressure compressor and the main compressor.
5. The process for retrofitting an industrial gas turbine engine of
a power plant of claim 3, and further comprising the steps of:
adding a gear box between the new electric generator and the high
pressure compressor shaft.
6. The process for retrofitting an industrial gas turbine engine of
a power plant of claim 1, and further comprising the steps of:
removing at least one stage of the stator vanes form the high
pressure turbine; installing new at least one stage of stator vanes
in the high pressure turbine in which the new stator vanes have a
closed loop cooling circuit; providing a source of compressed air
for cooling of the new stage of turbine stator vanes; and,
discharging spent cooling air from the new stage of turbine stator
vanes into the combustor that produces the hot gas stream for the
high pressure turbine.
7. The process for retrofitting an industrial gas turbine engine of
a power plant of claim 6, and further comprising the steps of:
bleeding off cooling air from the high pressure compressor;
intercooling the cooling air; increasing the pressure of the
cooling air to a pressure slightly higher than an outlet pressure
of the high pressure compressor; and, passing the higher pressure
cooling air through the closed loop cooling circuit in the new
stage of turbine stator vanes.
8. The process for retrofitting an industrial gas turbine engine of
a power plant of claim 6, and further comprising the steps of:
compressing ambient air with an external compressor to a pressure
slightly higher than an outlet pressure of the high pressure
compressor; intercooling the cooling air; and, passing the higher
pressure cooling air through the closed loop cooling circuit in the
new stage or stages of turbine stator vanes.
9. The process for retrofitting an industrial gas turbine engine of
a power plant of claim 6, and further comprising the steps of:
bleeding off compressed cooling air from an outlet of the high
pressure compressor; intercooling the compressed cooling air;
increasing the pressure of the compressed cooling air to a pressure
slightly higher than an outlet pressure of the high pressure
compressor; and, passing the higher pressure cooling air through
the closed loop cooling circuit in the new stage of turbine stator
vanes.
10. The process for retrofitting an industrial gas turbine engine
of a power plant of claim 6, and further comprising the steps of:
bleeding off compressed cooling air from an outlet of the high
pressure compressor; increasing the pressure of the compressed
cooling air to a pressure slightly higher than an outlet pressure
of the high pressure compressor; intercooling the compressed
cooling air; and, passing the higher pressure cooling air through
the closed loop cooling circuit in the new stage or stages of
turbine stator vanes.
11. The process for retrofitting an industrial gas turbine engine
of a power plant of claim 6, and further comprising the steps of:
bleeding off some of the compressed air from the compressed air
line between the low pressure compressor and the high pressure
compressor for use as the cooling air for the new stage of turbine
stator vanes; and, cooling and compressing the cooling air to a
pressure slightly higher than an outlet pressure of the high
pressure compressor.
12. The process for retrofitting an industrial gas turbine engine
of a power plant of claim 1, and further comprising the steps of:
adding a variable inlet guide vane assembly to both the main
compressor and the low pressure compressor.
13. A power plant with a retrofitted industrial gas turbine engine
capable of producing greater power and at high efficiency, the
power plant comprising: an old main compressor driven by a high
pressure turbine with a combustor; a new inlet for the old main
compressor capable of greater compressed air flow; re-using the old
electric generator; a low spool with a new low pressure turbine or
an old power turbine driven by exhaust gas from the high pressure
turbine; a new low pressure compressor driven by the low pressure
turbine; a new compressed air line connecting the new low pressure
compressor to the new inlet of the high pressure compressor; and, a
new variable inlet guide vane assembly for the new low pressure
turbine or the old power turbine.
14. The power plant of claim 13, and further comprising: the old
main compressor is without at least one stage of stator vanes and
rotor blades such that a pressure ratio is optimally matched
between the main compressor and the new low pressure
compressor.
15. The power plant of claim 13, and further comprising: the high
pressure turbine has at least one stage of new stator vanes with a
closed loop cooling circuit; a source of compressed cooling air; a
compressed air cooling circuit to deliver compressed cooling air to
the closed loop cooling circuit of the stator vanes and discharge
spent cooling air into the combustor.
16. The power plant of claim 15, and further comprising: a new
boost compressor between the source of compressed cooling air and
the stage of stator vanes to increase the pressure of the cooling
air; and, a new intercooler between the source of compressed
cooling air and the stage of stator vanes to cool the compressed
cooling air.
17. The power plant of claim 13, and further comprising: Replacing
the old electric generator with a new electric generator driven by
the old main compressor with the new electric generator having a
greater electrical power production than the old electric
generator.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit to U.S. Provisional
Application 62/299,248 filed on Feb. 24, 2016 and entitled PROCESS
FOR RETROFITTING AN INDUSTRIAL GAS TURBINE ENGINE FOR INCREASED
POWER AND EFFICIENCY.
BACKGROUND OF THE INVENTION
Field of the Invention
[0003] The present invention relates generally to a power plant
with an industrial gas turbine engine, and more specifically to a
process for retrofitting an industrial gas turbine engine for
increased power and efficiency.
Description of the Related Art including information disclosed
under 37 CFR 1.97 and 1.98
[0004] Single shaft gas turbine engines are limited in power and
efficiency when pressure ratios and firing temperatures are raised
to the point where the last turbine stage is loaded to where Mach
numbers reach the maximum aerodynamic capability. In these cases,
the engine has limited capability to be upgraded for either power
or efficiency. In some cases, the two shaft engine configuration is
coupled to a larger free spinning turbine with the generator on the
low speed shaft to create an upgrade in power. This also has
limitations in total flow and is limited in the maximum pressure
ratio that the unit could sustain.
BRIEF SUMMARY OF THE INVENTION
[0005] In the present invention, existing single shaft turbine
engines are retrofitted with a low speed turbine coupled to a low
speed compressor that is aerodynamically coupled in front of the
existing compressor, now deemed the high compressor, where the
existing turbine (now deemed the high pressure turbine) is coupled
to the low speed turbine. Further enhancements to the cooling
systems enhance the ability to increase the firing temperature of
the existing section of the gas turbine and elevate the overall
power rating and efficiency.
[0006] A process for retrofitting an industrial gas turbine engine
in which a new independently operated low spool shaft with a power
turbine and a low pressure compressor is installed with the low
pressure compressed air being directed into an inlet of the high
pressure compressor. A variable area turbine vane assembly is added
to the power turbine and a variable inlet guide vane to the low
pressure compressor. In another embodiment, a power turbine that
drives an electric generator is retrofitted by using the power
turbine to drive a low pressure compressor that feeds low pressure
air to an inlet of the high pressure compressor, and relocates the
electric generator to the high speed shaft on a cold end of the
compressor. Regenerative or closed loop cooling can also be used to
increase efficiency by bleeding off air from the compressor,
cooling the air and then pressurizing the air further in order to
pass through stator vanes for cooling, where the spent cooling air
is then discharged into the combustor upstream of the flame. Air
for cooling can be bled off from a middle stage of the compressor
or from the exit end of the compressor. Or, ambient air from
atmosphere can be used with an external compressor to further
compress the air to P3 level followed by intercooling prior to
cooling of the stator vanes.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0007] FIG. 1 shows a single shaft industrial gas turbine engine
that drives an electric generator of the prior art.
[0008] FIG. 2 shows a retrofitted industrial gas turbine engine
with a low speed low pressure turbine and low pressure compressor
of the present invention.
[0009] FIG. 3 shows a turbine exhaust system for a retrofitted
engine of the present invention.
[0010] FIG. 4 shows a single shaft retrofitted industrial gas
turbine engine with at least one of the high pressure compressor
stage removed.
[0011] FIG. 5 shows a prior art two shaft industrial gas turbine
engine with a low speed power turbine driving an electric
generator.
[0012] FIG. 6 shows a retrofitted two shaft industrial gas turbine
engine with an electric generator and an optional gearbox on the
high speed shaft of the present invention.
[0013] FIG. 7 shows a low spool retrofitted with a high pressure
turbine having regenerative cooling of the present invention.
[0014] FIG. 8 shows a single shaft industrial gas turbine engine
comprising a turbine vane cooling system retrofit with bleed air
from the compressor intercooled and then further compressed with
regenerative cooling before discharge into the combustor of the
present invention.
[0015] FIG. 9 shows an industrial gas turbine engine comprising a
turbine vane cooling system retrofit with ambient air compressed
and then cooled to provide cooling for a row of stator vanes in the
turbine before discharge into the combustor of the present
invention.
[0016] FIG. 10 shows an industrial gas turbine engine comprising a
turbine vane cooling system retrofit with bleed air intercooled and
then further compressed for use in turbine vane cooling and then
discharged into the combustor of the present invention.
[0017] FIG. 11 shows an industrial gas turbine engine comprising a
turbine vane cooling system retrofit with bleed air compressed and
then intercooled for use in turbine vane cooling and then
discharged into the combustor of the present invention.
[0018] FIG. 12 shows an industrial gas turbine engine comprising a
turbine vane cooling system retrofit with compressed air further
compressed and then intercooled for use in turbine vane cooling and
then discharged into the combustor of the present invention.
[0019] FIG. 13 shows an industrial gas turbine engine comprising a
turbine vane cooling system retrofit with bleed air compressed and
then intercooled for use in turbine vane cooling and then
discharged into the combustor of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0020] The present invention is a process for retrofitting an
industrial gas turbine engine of a power plant for increased power
and efficiency.
[0021] In the present invention, existing single shaft turbine
engines 10 like that shown in FIG. 1 are retrofitted with a low
speed turbine (LST) coupled to a low speed compressor (LSC) that is
aerodynamically coupled in front of the existing compressor, now
deemed the high pressure compressor (HPC), where the existing
turbine (now deemed the high pressure turbine or HPT), is coupled
aerodynamically to the low speed turbine (LST). The existing single
shaft industrial gas turbine engine includes a compressor 11 driven
by a turbine 13 with a combustor 12, and an electric generator 14
driven by the rotor on the cold side which is in front of the
compressor 11. Bearings 15 support the rotor of the engine.
[0022] Further enhancements to the cooling systems enhance the
ability to increase the firing temperature of the existing section
of the gas turbine and elevate the overall power rating and
efficiency. The retrofit-able upgrade consists of several optional
elements. Most or all of the cooling air used to cool turbine
airfoils is discharged into the combustor upstream of the flame
instead of into the hot gas path of the turbine in order to improve
the efficiency of the engine. In one embodiment, some of the
turbine airfoil cooling air can be discharged through trailing edge
exit holes and into the hot gas stream with most of the spent
cooling air being discharged into the combustor. Passing cooling
air through the turbine airfoil for cooling and then discharging
most or all of the spent cooling air is referred to as a closed
loop cooling where the cooling circuit in the turbine airfoil is a
closed loop instead of an open loop in which all of the cooling air
is discharged out from the airfoil and into the hot gas stream
through film holes or exit holes in the airfoil.
[0023] The first upgrade element is to introduce a low speed
turbine (LST) 21 directly driving a low speed compressor (LSC) 22
is coupled aerodynamically to the existing single shaft industrial
gas turbine engine (IGTE) 10. The existing industrial gas turbine
exhaust system is removed and replaced with a close coupled turbine
section featuring a variable area low pressure turbine stator vane
(turbine 21 with variable turbine inlet guide vanes 25). This
variable turbine stator vane 25 is used in conjunction with the low
compressor variable geometry, Inlet guide vane and variable
geometry Stator guide vanes part of compressor 22, to control the
low shaft speed and to simultaneously match the low speed and the
high speed compressor for aerodynamic performance (FIG. 2).
[0024] The discharge of the low pressure compressor 22 is connected
aerodynamically to the inlet of the existing compressor 11 through
a compressed air line 23, now the high pressure compressor 11,
boosting the overall pressure ratio of the engine. The generator
connected to the original gas turbine is now defined as being on
the high speed shaft, as the new turbine 21 and compressor 22 make
the low speed shaft.
[0025] The existing gas turbine has the exhaust diffuser removed
and is close coupled to the new low pressure gas turbine 21 with
the variable area turbine stator vane 25. The flow discharging the
existing gas turbine 13 now enters the low pressure gas turbine 21
which passes through the variable area turbine stator vane 25 and
passes across the low speed turbine and out the new exhaust system
(FIG. 3). A turbine exhaust duct 26 is installed to pass the high
pressure turbine exhaust into the low pressure turbine and variable
inlet guide vanes 25.
[0026] The retrofit in this configuration can increase the existing
industrial engines overall pressure ratio significantly, a range
from 1.1 to even over 7.times., thus greatly enhancing the engines
mass flow and power output. The upgrade including the new low
pressure gas turbine 21 may entail removing one or more of the
front high pressure compressor blading stages 11A to optimally
match the pressure ratio split between the low pressure and high
pressure compressors 11A and 22 (FIG. 4). A new inlet 24 to the
high pressure compressor 11A is also added to receive the
compressed air from the low pressure compressor 22. To get the
maximum power out of the upgraded engine and higher efficiency at
low power modes, variable inlet guide vane assemblies are used in
the high pressure compressor and the low pressure compressor and
the low pressure turbine in order to control flows.
[0027] An alternate embodiment of this invention is to retrofit a
two shaft gas turbine, where the high speed shaft has a compressor
11 and turbine 13 on one shaft, and a low speed turbine (Power
turbine) 15 driving a generator 14 or mechanically driven equipment
(Pump, process compressor etc.) as shown in the FIG. 5 embodiment.
In the FIG. 6 embodiment, the power turbine 21 is used to drive a
low speed compressor 22 that is connected aerodynamically to the
existing compressor 11 (Now deemed the high pressure compressor)
through compressed air line 23. The generator 14 is moved to the
high speed shaft connected on the cold end of the high pressure
compressor 11. In the FIG. 6 embodiment, one or more stages of the
front of the high pressure compressor 11A would be removed in order
to match a pressure ratio split between the LP compressor 22 and
the HP compressor 11A.
[0028] In the process for retrofitting the prior art IGT engines in
FIGS. 1 and 5, the old electric generator would require replacement
since the retrofitted IGT engine would then produce around twice
the power as the old engine and thus require a new electric
generator. For example, if a prior art IGT single spool engine of
FIG. 1 which is capable of producing 300 MW of power is
retrofitted, the new IGT engine would be capable of producing twice
that power or 600 MW. Thus, the old 300 MW electric generator would
need to be replaced with a 600 MW electric generator. The old 300
MW electric generator could be reused, but a second 300 MW
generator would have to be added in which both generators would be
driven by the same output shaft. This modification would probably
be more costly than replacing the old 300 MW generator with a new
modern 600 MW generator. In limited upgrade cases, the old electric
generator can still be used with a slightly more powerful
industrial engine upgrade. The electric generator is chosen that
has the capability of producing more electrical energy than the IGT
engine operating at a standard operating temperature so that when a
cold day occurs and the engine can produce more power, the electric
generator can produce more power. Thus, if an IGT engine upgrade
does not produce more power than the electric generator is capable
of producing, then the old electric generator can still be used in
the upgraded IGT engine.
[0029] The second upgrade elements are cooling system retrofits and
are also available to be created alone, or in combination with the
low speed spool retrofit. This use of regenerative (closed loop)
cooling for the first several rows of cooled turbine vanes in the
now high speed turbine 13 are implemented where the existing
turbine stator vanes with cooling flow discharges into the gas path
(such as through film cooling holes or exit holes) are replaced by
stator vanes that collect the post cooling coolant and return it
into the combustor 12 upstream of the flame. The use of the
regenerative or closed loop cooling increases the thermal
efficiency of the engine, and further enhances the overall power
and efficiency coupled with the low speed compressor 22 and turbine
shaft (FIG. 7). Cooling air line 27 passes the spent turbine vane
cooling air into the combustor 12.
[0030] The cooling system if upgraded alone, would source cooling
air from one of several places. This first option would be from
ambient air such as that in FIG. 9 with the external cooling air
compressor 33 driven by a motor 32 would raise the cooling air
pressure to the required level.
[0031] In the FIG. 8 embodiment, the cooling air compression could
be partially compressed (bled off from a stage of the HPC 11),
intercooled with an intercooler 31, and further compressed for
reduced compressor work and increased compressor efficiency, and
then to reduce the cooling air compressor to the desired coolant
temperature. Cooling air is bled off from a stage of the compressor
11, passed through an intercooler 31, and then boosted in pressure
by compressor 33 so that enough pressure remains in the cooling air
after passing through the stator vanes in order to discharge the
spent cooling air into the combustor 12. Cooling air passage 34
from the compressor 11 can come from the compressor exit or from an
earlier stage which is at a lower pressure than the exit discharge
pressure.
[0032] A second approach is shown in FIG. 9 where this ambient
sourced air is compressed and then cooled in an intercooler to the
desired cooling air temperature. In this second case the cooling
air work of compression is higher than in the FIG. 8 embodiment,
however the configuration could be made simpler. In the third and
fourth case the cooling air is bled from one of the existing
compressor bleed ports where the flow is both intercooled and
recompressed in the third case, or compressed and after-cooled
being the fourth case, FIGS. 10 and 11.
[0033] A fifth case the fully compressed air from the main
compressor is extracted and cooled and then further compressed,
FIG. 12. A sixth option is extracting the cooling air from the
compressor exit and further compressing followed by post cooling to
the desired cooling air temperature for vane cooling, FIG. 13.
[0034] In each of these cases the externally compressed cooling air
is created at a pressure significantly over the main compressor 11
discharge pressure, commonly designated P3. This intercooled and
over pressurized coolant provides optimized low temperature high
pressure coolant to the turbine stator vanes to provide cooling of
the vanes to the desired level while the captured cooling flow
exiting the vane exists with positive pressure margin to pass it
into the combustor shell to mix with the existing compressor
discharge air.
[0035] This configuration of closed loop air cooing (meaning most
or all of the airfoil cooling air is discharged into the combustor
instead of the hot gas stream through the turbine) optimized
thermal efficiency and augments power by increasing the overall
flow through the combustor while preventing coolant form diluting
the main hot gas stream. By closed loop cooling of the turbine
airfoil, the present invention means that most or all of the spent
cooling air passing through the turbine airfoils is discharged into
the combustor instead of being discharged into the hot gas
stream.
[0036] In the cases where the regenerative turbine vane cooling
implemented on the HPT is coupled with the low spool turbine and
compressor, the cooling air source could be from the LPC discharge,
or from an intermediate LPC bleed, HPC bleed or the HPC compressor
discharge.
* * * * *