Recent Advances in Ultra Super Critical Steam Turbine

Recent Advances in Ultra Super Critical

Steam Turbine Technology

M. Boss T. Gadoury S. Feeny M. Montgomery

GE Energy, Steam Turbine Technology

1 River Road, Schenectady, NY 12345

Un‐Hak Nah Sung I. Cho Seong H. Yang

Doosan Heavy Industries & Construction Co., Ltd.

555 Gwigok‐Dong, Changwon, Gyeongnam, Korea

Abstract – With the continuing drive to reduce power plant emissions including green house

gases, coal fired power plants have been moving to higher ultra‐supercritical (USC) steam conditions in

addition to advances in technology. GE Energy and Doosan Heavy Industries are designing the next

generation USC power plant with a rating of 1000 MW to address the need for higher efficiency coal

fired power plants. With inlet steam conditions of 260 bar and 610ºC / 621ºC (3770 psi and 1150°F /

1180°F), the primary objective for the advanced technology USC 1000 MW steam turbine is high

efficiency. To achieve this higher cycle efficiency, the design utilizes advanced steam turbine technology

and system design, a longer last stage bucket design in addition to ultra supercritical steam conditions.

Performance enhancing technology is being applied to turbine buckets, nozzles and seals. In

addition to improvements to steam path components, performance gains are achieved by optimizing

stationary components such as valves, inlets and exhausts using advanced CFD tools.

This new USC project will illustrate the latest design and technology capabilities of GE Energy

and Doosan Heavy Industries and will set the standard for future 1000 MW USC applications in Korea,

as well as elsewhere in the world.

1. INTRODUCTION

After more than 100 years of progressive invention and improvement, the steam turbine

continues to be the most used prime mover of the world’s power generation industry. Innovations such

as Edison’s light bulb and Tesla’s induction motor resulted in a phenomenal demand for electric power

driven by steam turbines, which have exponentially grown to more than 56 GW of capacity in Korea and

almost 3,000 GW worldwide. Steam turbines generate more than 80% of the total electric power

throughout the world.

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GE Energy was an early entrant into USC steam turbine technology with the first unit shipped in

1956 with inlet steam conditions of 310 bar / 621°C (4500 psi / 1150°F). Since then, GE has shipped

77GW of steam turbines (125 units) with supercritical steam conditions. GE designed the world’s

most powerful USC steam turbine rated 1050 MW operating at 250 bar / 600°C / 610°C (3626 psi /

1112°F / 1130°F). Over the past five years, GE has co‐produced with Doosan Heavy Industries 16 units

with USC steam conditions. The 1000 MW USC steam turbine design is a nature evolution of GE’s USC

technology. GE continues to develop and refine USC steam turbine technology.

GE Energy has licensed its technology to Doosan Heavy Industries (formerly Korea Heavy

Industries and Construction Company) resulting in the development and installation of GE Energy steam

turbine and generator technology for the Korean power industry. During this period, the two

companies have designed, manufactured and installed:

16.1 GW of coal‐fired steam turbine generating capacity

2.4 GW of combined‐cycle steam turbine generating capacity

10.4 GW of nuclear turbine generating capacity.

To date, there are 70 GE Energy steam turbines and generators planned or installed for projects

in Korea, including combined‐cycle, nuclear, sub‐critical coal‐fired and supercritical coal‐fired steam

turbine applications. Fifty‐one of these steam turbines have been co‐produced with Doosan. Current

ongoing projects with planned commercial operation in 2006 thru 2008 include:

• 2 x 550MW USC Korea East‐West Power Co. (KEWESPO) Tangjin #7 & #8

• 2 x 550MW USC Korea Western Power Co. (KOWEPO) Taean #7 & #8

• 2 x 550MW USC Korea Midland Power Co. (KOMIPO) Poryeong #7 & #8

• 2 x 550MW USC Korea Southern Power Co. (KOSPO) Hadong #7 & #8

In addition to advanced steam turbine technology operating at steam conditions of 241 bar /

566°C / 593°C (3500 psi / 1050°F / 1100°F), these power plants also feature the latest technology in

once‐through USC boilers supplied by Doosan. These boilers will have improved heat efficiency to

further increase the plant’s capability to compete in the new Korean power market environment.

With the emerging interest to reduce emissions, including green house gases, from coal fired

power generation, GE Energy and Doosan are striving to increase USC PC generation output and

efficiency in its co‐development of this 1000MW USC PC platform. Every 1% improvement in plant

efficiency results in approximately 2.5% reduction in green house gas emissions. To satisfy this

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objective, both GE Energy and Doosan’s steam turbine technology and Doosan’s boiler technology is

looking to achieve the following advances in PC generation technologies:

MW rating: 1000MW MGR

HP throttle pressure: 260 bar (3770 psi)

HP throttle temperature: 610°C (1130°F)

Reheat steam temperature: 621°C (1150°F)

Condenser pressure: 1.5” Hg (NR Back Pressure: 2.5” Hg)

4 flow, 45 inch Last Stage Blade

Cycle: Single Reheat Regenerative

2. TECHNOLOGY of USC STEAM TURBINE

2.1 Cycle Overview

In the evaluation of steam conditions, the potential cycle efficiency gain from elevating steam

pressures and temperatures must be considered. Starting with the traditional 165 bar / 538°C (2400 psi

/ 1000°F) single reheat cycle, dramatic improvements in power plant performance can be achieved by

raising inlet steam conditions to levels up to 310 bar (4500 psi) and temperatures to levels in excess of

600°C (1112°F). Every 28°C (50°F) increase in throttle and reheat temperature results in approximately

1.5% improvement in heat rate.

The feedwater heater arrangement is designed to obtain the best heat rate for a given set of USC

steam conditions. In general, the selection of higher steam conditions will result in additional feedwater

heaters and a higher final feedwater temperature. The higher final feedwater temperature will have an

impact on the boiler cost. This then requires a system level optimization to determine the best

economical solution for the increase in final feedwater temperature. In many cases, the selection of a

heater above the reheat point (HARP) also is warranted. The use of a separate de‐superheater ahead of

the top heater for units with a HARP can result in additional gains in unit performance.

The selection of the cold reheat pressure is an integral part of any power plant design, but

becomes even more important for plants with advanced steam conditions. Comparing the heat rate at

the thermodynamic optimum, the improvement resulting from the use of a HARP can be about 0.6%.

However, economic considerations of the boiler design without a HARP tend to favor a lower reheater

pressure at the expense of a slight decrease in cycle performance. The resulting net heat rate gain is

usually larger, approaching 0.6‐0.7%. Changing the final feedwater temperature, adding a HARP, and

setting the reheater pressure obtain the best relative heat rate impact.

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The use of advanced reheat steam conditions strongly affects the inlet temperature to the low‐

pressure (LP) turbine section. An increase in hot reheat temperature translates into an almost equal

increase in crossover temperature for a given crossover pressure. However, the maximum allowable LP

inlet temperature is limited by material considerations associated with the rotor, crossover and hood

stationary components. In addition, the selection of hot reheat temperature (and corresponding effect

on LP inlet temperature) impacts the amount of moisture at the L‐0 bucket which factors into stress

corrosion cracking considerations.

Once the reheat steam conditions are established (pressure and temperature) then the LP steam

conditions can be determined. If the resulting crossover temperature is too high, the energy ratio

between the IP and the LP can be changed to lower this temperature. Increasing the energy on the IP

section will lower the crossover temperature, but it will also impact the cycle efficiency, increase the

number of IP stages, or the loading of the IP stages, increase the height of the final IP bucket, increase

the size of the crossover, or increase the pressure drop through the crossover.

2.2 Steam Turbine Configuration

The appropriate steam turbine configuration for a given USC application is largely a function of

the number of reheats selected, the unit rating, the site back pressure characteristics and any special

requirements such as district heating extractions. Specific design details will also determine the number

of flows in a turbine section, the number of stages and the last stage bucket (LSB) length.

In particular, the site ambient conditions and the condensing system will play a huge role in the

selection of the LSB and the number of LP section flows. The 38.1 mmHgA (1.5” HgA) would be for a

direct cooled condenser, or cooling towers in a cold environment. The 88.9 mmHgA (3.5” HgA) would

be for cooling towers in an area with warmer ambient temperatures.

The expected exhaust pressure of the plant at the time of maximum expected power production

should be considered in the design the LP section. At 1.5” HgA, and 1000 MW output, a 45” LSB and a

6‐flow LP section would achieve the best heat rate. At 3.5”HgA, and an output of 1000 MW, the 40” LSB

and a 4‐flow LP section would be the lowest heat rate choice. In either of these cases, the high pressure

(HP) and intermediate pressure (IP) sections would be essentially the same.

The turbine cost increases and plant cost increases would then be compared to the expected

kilowatt outputs to optimize the plant Cost of Electricity. In the case of the 3.5” HgA, the 4‐flow 40”

would be higher cost than the 4‐flow 33.5”, and the footprint of the 40” LP section would be larger also.

In the case of the 1.5” HgA chart, the 6‐flow LP section would require the additional LP turbine section,

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and additional condenser, as well as a larger footprint for the 45” LP section.

These considerations resulted in the selection of a 4‐flow 45” LP section design. The overall

turbine configuration is shown in Figure 1.

© 2007, General Electric Company

Figure 1 ‐ 4‐casing, 4‐flow LP Configuration

2.3 Evaluation of Ultra Super Critical Technology

The history of steam turbine development is basically an evolutionary advancement toward

greater power density and efficiency. Improvements in the power density of steam turbines have been

driven largely by the development of improved rotor and bucket alloys as well as improvements in the

design and analysis of the attachment devices for the vanes. This has increased the allowable stresses

and enabled the construction of longer last stage buckets for increased exhaust area per exhaust flow.

Increases in efficiency have been achieved largely through two kinds of advancements: (1)

improving expansion efficiency by reducing aerodynamic and leakage losses as the steam expands

through the turbine; and (2) improving the thermodynamic efficiency by increasing the temperature

and pressure at which heat is added to the power cycle. The latter improvement is the core of USC

technology.

The design of the Ultra Super Critical steam turbine for the present development will incorporate

the new technologies, which consist of:

i) Improvement of in the power density of steam turbines such as;

Increased number of stages

Decreased inner ring diameter

Optimized stage reaction levels

Optimized Stage energy levels

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ii) Mechanical design elements including:

Advanced sealing

Integral cover bucket (ICB)

Full Arc, hook diaphragm 1st stage

Advanced cooling scheme

iii) Improved HP/IP/LP shell design

iv) Advanced LP design with 45 inch last stage blade

3. HIGH/INTERMEDIATE PRESSURE TURBINE DESIGN

3.1 High Pressure (HP) Section Design

3.1.1 Section Design

Figure 2 shows the HP cross‐section. The HP section is designed in a single flow configuration.

This modern design eliminated the partial admission, control stage, and nozzle box. An overload

admission was added for frequency control and capacity margin. Main steam enters the section

through two pipes (top and bottom.) A heater above reheat point extraction is taken from the lower

half. The HP exhaust uses two cold‐reheat (CRH) pipes from the lower half arranged in the pant leg

configuration. Elimination of the nozzle box required that two inner shells be used. All shells are split

and bolted at their horizontal joints for ease of maintenance. In this arrangement, the inlet #1 inner

shell is subject to adjacent stage steam conditions on its’ inner surfaces and a downstream stage’s

steam pressure on its outer surface. The corresponding outer shell inner surface is subjected to steam

conditions at the same downstream steam pressure albeit with an enthalpy determined by the flow

balance of steam between the packing leakage and the split location. The exhaust #2 inner shell is

arranged in a manner similar to that for the full inner shell described above. The inner shell split

location is judiciously chosen to optimize the horizontal joint and bolting design of the outer, #1 inner,

and #2 inner shells. The outer and # 1 inner shell are cast 10Cr material. The #2 inner shell is cast

CrMoV material. The mono‐block rotor material is 12Cr. The Advancing steam conditions necessitated

the addition of inlet cooling for the rotating parts to allow the rotor design to stay 12Cr materials. Full

admission design alleviated the mechanical challenges associated with partial admission design and the

control stage. Thrust is balanced using the pressure difference across the rotor at the generator end of

the HP section. The rotor is supported by bearings in the front and middle standards. Both standards

slide in a manner conventional to GE 4 casing, 4‐flow turbine construction.

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Figure 2 ‐ HP Section Arrangement

3.1.2 High Pressure Steam Path

The HP steam path has 10 stages. The first stage is full‐arc admission. The HP staging is

designed in a manner typical for GE’s proven designs using Dense PackTM steampath components. The

buckets of the first four stages are made of nickel‐based material due to the high temperature creep

requirements. The remaining buckets are conventional 12Cr materials. All 10 stages will utilize integral

cover buckets (ICB) with advanced tip seals. Figure 3 shows a typical GE ICB design. The wheel spaces of

the first two stages are cooled using external cooling steam. The first five stages of diaphragms utilize

10Cr materials. The remaining five stages of diaphragms use 12Cr web and ring material. A combination

of brush, variable clearance, and conventional shaft seals are used in the HP section.


Figure 3 ‐ Typical GE ICB Design

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3.2 Intermediate Pressure (IP) Section

3.2.1 Section Design

Figure 4 shows the intermediate‐pressure cross‐section. The IP section is designed in a double

flow configuration. Steam enters the section through two pipes in the lower half. Two feed water

heater extractions are taken from the lower half. The IP exhaust uses two cross over connections from

the upper half arranged in the manner conventional to GE 4 casing, 4‐flow turbine construction. Single

shell construction is used. The shell is split and bolted at its horizontal joint to minimize clearances

and reduce manufacturing cost. The shell is cast 10Cr material. The mono‐block rotor material is 12Cr.

The advancing steam conditions necessitated the addition of inlet cooling for the rotating parts. The

rotor is supported by bearings in the middle standard and LPA standards. Both standards slide in a

manner conventional to GE 4 casing, 4‐flow turbine construction.


Figure 4 ‐ IP Section Arrangement

3.2.1 Steam Path Design

The IP steam path has 8 stages. The IP staging is designed in a manner typical for GE’s proven

designs using Dense PackTM components. The buckets of the first three stages are made of nickel‐based

material due to high temperatures. The remaining buckets are conventional 12Cr materials. All 8 stages

will utilize integral cover buckets (ICB) with advanced tip seals. The wheel spaces of the first two stages

are cooled using cooling steam, from HP section. The first two stages of diaphragms utilize 10Cr

materials. The remaining six stages of diaphragms use 12Cr web and ring material. A combination of

variable clearance and conventional shaft seals are used in the IP section.

3.3 Aerodynamic Design

3.3.1 Advanced Aero Design

The biggest advance in steam turbines in recent years has been Aerodynamics. GE has

continued to develop advance aerodynamic vane shapes based on 100 years of experience coupled

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with 3D CFD (computational fluid dynamics) and GE’s HP test facility. The addition of CFD in the last 10‐

15 years has resulted in great strides in steam turbine aerodynamics. Figure 5 shows the evolution of

aerodynamic shapes over the years.

Stea

m P

ath

Effic

ienc

y %

Free -Vortex• Uniform Radial

Controlled -Vortex• Non-Uniform Radial Flow• Straight Trailing Edge

Advanced -Vortex• Compound Lean • Bowed Nozzle

Partitions

1960’sFree -

VortexDesign

1970’sImproved

Vane Profiles

1980’sControlVortexDesign

1990’sAV1, adv

RTSS

Late 1990’sAV2, ICBs,

opt. clearance

2000’sDense Pack

2000’sDense Pack ™

w/adv sealing


Flow

Controlled- Vortex• Non Uniform Radial Flow• Straight Trailing Edge• Optim ized Reaction

Advanced - Vortex• Compound Lean • Bowed Nozzle

Partit ions

-

Stea

m P

ath

Effic

ienc

y %




Partitions

1960’sFree -

VortexDesign

1970’sImproved

Vane Profiles


1990’sAV1, adv

RTSS


opt. clearance

2000’sDense Pack


w/adv sealing


Flow



Partit ions

- New Design

Adv Sealing

Stea

m P

ath

Effic

ienc

y %




Partitions

1960’sFree -

VortexDesign

1970’sImproved

Vane Profiles


1990’sAV1, adv

RTSS


opt. clearance

2000’sDense Pack


w/adv sealing


Flow



Partit ions

-

Stea

m P

ath

Effic

ienc

y %




Partitions

1960’sFree -

VortexDesign

1970’sImproved

Vane Profiles


1990’sAV1, adv

RTSS


opt. clearance

2000’sDense Pack


w/adv sealing


Flow



Partit ions

- New Design

Adv Sealing


Figure 5 ‐ Evolution of Steam Turbine Aerodynamics

GE’s designs using Dense PackTM components further improve efficiency by addressing the major

sources or aerodynamic loss in impulse steam turbines. This is achieved via:

• Higher bucket reaction ‐> Decreased nozzle velocity/turning ‐>Decreased nozzle profile and

secondary losses

• Reduced nozzle and bucket counts ‐> Decreased friction loss

• Decreased root diameter ‐> Increase bucket active length ‐> Improved bucket efficiency

In addition, the higher reaction and decreased root diameter result in additional stages (in

order to keep optimum wheel velocity ratio). These additional stages improved section efficiency.

3.3.2 High Pressure Turbine 1st Stage

Older steam turbine designs utilized a control stage to control pressure and load during

transient conditions. The mechanical design requirements of this stage, having to withstand partial arc

stimulus, often result in a very large and in‐efficient 1st stage design that can be 5‐10% lower efficiency

than the other HP stages. Although there have been many improvements to control stage design in

recent years as part of GE’s products using Dense PackTM components, the efficiency still lags other

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group stages. Therefore, for the new Korea 1000 MW USC standard GE and Doosan chose to implement

a full arc 1st stage design, which is much higher reaction and lower aspect ratio to a traditional control

stage. This enables the first stage design to rival the efficiency of other stages. To allow this however,

changes need to be made to allow the turbine to quickly and efficiently respond to load swings.

Therefore, GE and Doosan will utilize an overload valve that will bypass the 1st stage and allow

additional flow/load response. GE has utilized such a design previously and has a patent in this area.

3.3.3 High Pressure and Intermediate Pressure Cooling

As throttle temperatures increase, cooling becomes extremely important. For the new Korean

1000 MW USC standard, GE utilizes traditional type IP Cooling, and also HP cooling, which was utilized

on GE’s 1st USC machine in 1958. HP cooling takes lower enthalpy steam from the boiler and floods the

HP 1st stage wheel and N2 packing areas. This method has minimal performance penalty since lower

enthalpy steam feeds the leakage circuit and the high enthalpy steam stays in the steampath. In

addition, the IP cooling steam is mixed from 2 different sources, allowing better control of temperature,

minimizing flow and performance loss.

4. LOW PRESSURE TURBINE DESIGN TECHNOLOGY

4.1 Wheel and Diaphragm Configuration Structure

m© 2007, General Electric Co pany

Figure 6 ‐ Wheel and Diaphragm Configuration

As shown in Figure 6, the LP design for the 1000 MW consists of 5 stages with 4 extractions for

the feed water cycle. The last 3 stages (L‐0, L‐1, and L‐2) are designed as a system and the L‐0 utilizes

the new GE 45” Titanium LSB design. This provides the maximum annulus area for a 4‐flow

configuration. Titanium material is required due to the large load. In addition, advanced curved axial

entry dovetails have been developed to minimize stresses. High strength LP rotor material, similar to

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that used on GE’s 40” steel bucket is also used to control stress.

The first 2 LP stages (L‐3 and L‐4) utilize high reaction stage design for optimal efficiency. In

addition, advance brush seals are utilized to reduce leakage losses.

4.2 Exhaust Hood Design

The LP turbine section is a complex system, which requires a careful optimization to get the

proper balance of performance, cost, robust operability, and ease of maintenance. The elements of this

LP turbine section are: the outer exhaust hood, the inner casing, the stationary steam path, and the

rotor.

As the steam paths get larger, with the introduction of longer last stage buckets, the challenges

of the exhaust hood design become more critical. The exhaust hood must contain the vacuum

established in the condenser, it must support the rotor bearings, as well as the inner casing, and it must

have a design that allows for the proper diffusion of the steam leaving the last stage.

Three‐dimensional (3D) solid models of all of the components of the LP turbine allow for state‐

of‐the‐art analysis techniques, with respect to finite stress calculations, transient heat transfer

calculations, component response to heating and loading, and Computational Fluid Dynamic (CFD)

Analysis. The critical movements of the interfaces of the various components need to be understood to

be able to optimize the clearance calculation throughout the LP turbine. The required axial and radial

clearances can be calculated with the transient loading conditions for start‐up and shut down of the

machine. This together with a statistical analysis on the expected variation from the stack‐up,

manufacturing tolerances, and calculation uncertainty, yields the clearances for the machines. Figure 7

shows the exhaust hood outer model, which is a part of this analysis.


Figure 7 ‐ LP Exhaust Hood Model

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The LP exhaust hood directs the flow from the last stage bucket exit annulus to the condenser. The high

volumetric flows associated with the low exhaust pressure result in high exit Mach numbers making the

recovery of this exit kinetic energy or “Leaving Loss” an important feature of the LP turbine. To

maximize the recovery of the exit kinetic energy, the exhaust hood is designed using an unstructured

CFD mesh. Inlet boundary conditions are set to model the effects of the LSB exit flow profile.

Results of this model, shown in Figure 8, are used to refine the geometric definition of the

exhaust hood shape such that the flow losses are reduced and the leaving loss is recovered to the

maximum extent possible. In the exhaust, the placement and shapes of the butterfly plates, Herzog

plates and steam guides were design for the best performance. These changes reduced the high

velocity regions, minimized separations, and reduced flow turning resulting in reduced inlet and

exhaust pressure losses, contributing to the overall improved performance of the LP turbine.


Figure 8 ‐LP casing Model and CFD results

The LP inner casing inlet duct transitions flow from the crossover pipe to the annular inlets of

the steam path. 3D CFD analysis of the inlet region is employed to minimize the losses in this transition.

Results from this analysis provided the inlet boundary condition for the turbine analysis including both

radial and circumferential variation.

4.3 LP Inlet Design

In addition to the CFD work used to optimize LP Exhaust, similar methods are used for LP Inlets.

Although the velocities are much lower in the inlets, meaning that less performance is lost than in the

exhaust, some improvements can be made. Aside from the basic area rules of crossover to LP inlet to

1st stage used to avoid acceleration, the LP inlet shape can be designed to reduce pressure drop. Figure

9 shows a CFD analysis of an LP inlet before and after aerodynamic optimization. The colors represent

areas of different velocity. (red is high, blue is low)

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Figure 9 ‐ LP Inlet Optimization

5. ADVANCED SEAL DESIGN TECHNOLOGY

One of the biggest issues with increased reaction is the need for improved seals over the

bucket tips due to the higher pressure drops. In addition, to further efficiency improvements, improved

seals are also applied to diaphragms. GE’s wheel and diaphragm construction lends itself well to

application of a variety of advanced seals.

5.1 Elliptical Clearance Packing

The first, most basic advanced seal used is a standard hi‐lo or slant tooth packing with elliptical

packing. Elliptical packing has been shown through experience to be the best solution to minimize

leakage area while preventing most rubs. Clearances tend to be larger at the vertical position as

opposed to the horizontal position due to rotor and stationary part movements. Recent CFD analyses as

well as component testing has shown that rubbed packing shapes have a much higher leakage than a

sharp toothed packing (see Figure 10).


Figure 10 ‐ Rubbed packing CFD

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Elliptical clearances are used in conjunction with other advanced seals in most areas.

5.2 Variable Clearance Positive Pressure Packing

In the 1990’s GE introduced its proprietary variable clearance positive pressure packing

(VCPPP). This design provides improved rub resistance, as the packing is “open” while the turbine is

starting up. Unlike conventional packing where the spring pushes the packing ring toward the rotor, the

spring on VCPPP packing pushed the ring away from the rotor by a prescribed amount. Once the

turbine starts to increase in load, pressure builds up and “closes” the ring against the hook. This is

beneficial as the rotor has already gone through its critical speeds and much of the thermal transient

conditions that lead to rubbing have passed. GE applies VCPPP where pressure drops are large enough

to close the rings.

5.3 Brush Seals

Brush seals have been used in GE steam turbines since the 1990’s and have proven to be very

beneficial. Brush seals, unlike traditional packing, are designed to contact during normal operation. The

“bristle” material is designed for heavy wear, thus resulting in a minimal clearance during the life of the

turbine. Brush seals are most effective where there are large pressure drops, however there is some

limitations on pressure drop based on backplate stress. Brush seal usage is also limited based on rotor

dynamics criteria. Since the seals are designed to rub, there is heat generation in the rotor locally to the

rub. This rub causes a thermal bow that can cause the rotor instability. Therefore, brush seals are

limited in number based on the rotor dynamics characteristics of a given rotor.

6. CONCLUSIONS

As global fuel prices are making coal‐fired fossil steam turbine generators increasingly more

attractive in the world generation market, the increased efficiency / reduction in emissions is of

paramount importance to the environment. USC steam conditions enable high efficiency designs that

reduce the amount of fuel required for generation and help reduce green house gas emissions.

GE Energy and Doosan are currently developing the next generation 1000 MW fossil PC steam

turbine generator platform, a design that includes will set a new standard for power plant performance

and economics, using state of the art analysis and technology.

REFERENCES

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1. J. Michael Hill, Sanjay Goel, “Development of the Dense Pack Steam turbine: A New Design

Methodology for Increased Efficiency”, Proceedings of 2000 International Joint Power Generation

Conference, 2000

2. Eichiro Watanabe, Yoshinori Tanaka, “Development of New High Efficiency Steam Turbine”,

Mitsubishi Heavy Industries, Ltd., Technical Review Vol. 40 No.4., Aug. 2003

3. Tom Logan, Un‐Hak Nah, James Donohue, “GE and Doosan bring Ultra Super Critical Steam Turbine

Technology to Korea”, Proceedings of 2003 Power Gen Asia, 2003.

4. Daniel Cornell, Klaus Retzlaff, Sean Talley, “DX2 (Dense Pack) Steam Turbines”, GER‐4202 GE Power

Systems.

5. Mujezinovic, A., Hofer, D., Barb, K., Kaneko, J, Tanuma, T. and Okuno, K, “Introduction of 40/48 Inch

Steel Steam Turbine Low Pressure Section Stages”, Proceeding of the Power‐GEN Asia, (2002), CD‐

ROM.

6. Hofer, D., Slepski, J., Tanuma, T. Shibagaki, T., Shibukawa, N., and Tashima, T., “Aerodynamic Design

and Development of Steel 48/40 inch Steam Turbine LP End Bucket Series”, Proceedings of the

International Conference on Power Engineering‐03 (ICOPE‐03) November 9‐13, 2003, Kobe, Japan

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Recent Advances in Ultra Super Critical Steam Turbine