As the steam path degrades in mature steam turbines performance loss often occurs. Reducing heat rate while increasing output can have a significant impact on earning potential within the current market and today’s regulatory conditions. Improvements of 3% or more have been seen by users who have installed the full package of steam turbine seals in their units. EthosEnergy has been developing advanced turbine sealing technologies that improve efficiency and performance of steam turbines for over 30 years.

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EthosEnergy SMART Seals:
Increasing Steam Turbine Performance and
Reliability
Power Magazine Webinar
January 29th, 2015

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Presentation Agenda:
• Causes and Effects of Steam Turbine Performance Losses
- Identifying normal wear on components critical to turbine performance
- Inherent OEM design problems
- Steam Path Degradation
• EthosEnergy Solutions to Steam Turbine Performance Losses
- EthosEnergy Energy Package
 SMART Turbine Seals
 Retractable Packing
 Brush Seals
 Brush Tips Seals
 Horizontal Joint Upgrade
 Articulated Snout Rings
 Steam Path Repairs
 Case Study – GE G2 Steam Turbine
SMART Turbine Seals

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+ Seventy percent of steam turbine performance loss can be attributed to steam
leakage at the shaft, blade tips, joint and inlet pipes
Steam Turbine Performance Loss
Areas of Performance Loss
30%
30%
20%
20%
General Aging of
the Steam Path
Shaft Seal
Leakage
Horizontal Joint
and
Inlet Leakage
Tip Seal
Leakage
*Data supported by steam path audits

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Conventional Turbine Shaft Packing
Labyrinth packing rings are used to control the flow
of steam between the stationary components and the
rotor

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Design
• Static multi-tooth seals at shaft
• Bronze or steel material
• Typical OEM design clearance of .020”/.508mm
Issues
• Static multi-tooth seals at shaft
• Clearances rub out as rotor goes through critical
• Cracked inserted teeth in certain locations
• Often replaced every outage
• Typical as found clearance after operation .045” /1.143mm
Conventional Packing Rings

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Conventional Blade Tip Seals
Another area for potential improvement is the blade
tip seals, which control steam leakage between the
stationary diaphragm and rotating blade

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Design
• Single or multi-tooth seal at blade tips
• Installed either in diaphragm or turbine case
• Typical OEM design clearance of 0.06“/1.524mm
Issues
• Rotor bowing from shaft rubs wipes out clearances
• Rotor vibration through critical wipes out clearances
• Typical as found clearance after operation .085”/2.159mm
• Erosion, especially on bronze tip seals
Conventional Tip Seals

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Conventional Snout Rings
Another area for potential improvement is snout
rings, which control steam leakage at the inlet
between the inlet pipe, outer and inner shells

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Design
• Interference fit with inlet pipe or turbine shell
• Interference fit at ambient and operating temps
Issues
• Oxidation due to material
• Oxidation can lead to seizing of rings
• Removal and installation require dry ice or heat
• Removal process can damage inlet pipe or turbine shell requiring repairs
• Often some rings are damaged and require replacement
Conventional Snout Rings

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Conventional Seal Rubs During Unit Start-up
Causes of Seal Rubs During Operation
Seal Rubs Occur

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Shaft and Blade Tip Leakage: Wear
Labyrinth Seal Operation Video
Two main causes of wear are mechanical damage and degradation
Seal Rubbing & Degradation Effects:
- Reduced Turbine Performance due to increased seal clearances
- Reliability Issues due to mechanical damage and thermal distortion
OEM Labyrinth Seals
“As Found” Condition at Outage

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Seal Rubbing Effects: Reliability Issues
Distortion due to thermal gradients
Potential for Rotor Distortion (aka Rotor Bow)

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Technology
• Retractable Packing (Late 1980’s)
• Retractable Brush Packing (1998)
• Brush Tip Seals (2003)
• Articulated Snout Rings (Early 1990’s)
• N2/Horizontal Joint Bolting Upgrade
(2010’s)
Experience (Global)
• 600+ Units Retractable
• 150+ Units Retractable Brush
• 30+ Units Brush Tip Seals
• 50+ Units Articulated Snouts
• 10 Units Horizontal Joint Upgraded
OEMS
• 400+ GE Units
• 100+ Westinghouse Units
• 30+ MHI/Toshiba/Hitachi Units
• Various other OEMs including Elliott,
Dresser Rand, Alstom
SMART Turbine Seals: Development Timeline

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SMART Turbine Seals: Retractable Packing
Click the image above
to play animation
Features:
• Larger than OEM design clearance during
turbine start-up and shut-down
• Static clearance typically .150” (3.8mm)
• Mitigate risk of seal rubs
• Improved leakage control compared to
conventional seals – operate at between
.015” - .025” clearance (0.38-0.64 mm)
• Can be installed in both industrial and utility
steam turbines (typical output range:
10,000hp – 1000 MW)
Benefits
• Recover and sustain lost power output and
turbine efficiency
• Improve unit reliability and cycling capability
• Reduce turbine heat rate
• Lower fuel consumption and Greenhouse Gas
emissions (CO2, SO2, NOx)

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SMART Turbine Seals: Retractable Brush Seals
Click the image above
to play animation
+ Features:
All features of Retractable Packing, in addition
to:
• Flexible and compliant seal element
• Minimize seal wear during all operating
periods
• “Zero Clearance” for optimal sealing
effectiveness (.002”/.05 mm) effective
clearance
+ Benefits
All benefits of Retractable Packing, in addition
to:
• Improve turbine efficiency above original
design
• Reduce turbine heat rate below original
design
• Increase maximum generating capability and
potential revenue
• Further reduction in Greenhouse Gas
emissions

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Steam Whirl Instability
• Shaft labyrinth seals can have
destabilizing effect on rotor
• Destabilizing effect can lead to excessive
levels of vibration
• Labyrinth seal destabilizing force
increases w/
– Reduced radial clearance
– Elevated pre-swirl at packing
entrance
– Higher steam density
– More restrictions (short seal only)
– Lower 1st critical speed
– Larger seal diameter
DIAPHRAGM
TIP
SPILL STRIPS
BALANCE HOLE
WHEEL
PACKING
SHAFT
STEAMFLOW
ROOT
SPILL STRIPS
ROTATING
BLADE
STATIONARY
BLADESTAGE
PRESSURE
DOVETAIL
INTERSTAGE PACKING LEAKAGE
BALANCE HOLE
FLOW
ROOT LEAKAGE
TIP
LEAKAGE
COVER OR
SHROUD
TENON

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Rotor Dynamic Analysis
• Typical Recommendations:
– Install multiple anti-swirl packing rings
– Use retractable design to minimize possibility of rubbing through critical
speed
– Review bearing design for possible improvements on stability margin
• Anti Swirl packing typically reduces steam whirl destabilizing forces by
150-200%
– Rotor stability margin significantly increased

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Solutions to Steam Whirl
• Limit turbine load
• Remove seal restrictions
• Increase seal clearance
• Improve journal bearings
– Tilting pad journal bearings can improve
damping and counteract destabilizing
forces
• Combine close clearance seals with anti-swirl
labyrinth features at selected locations to
reduce rotor destabilizing forces

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Conventional Packing w/ Anti-swirl Vanes

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Retractable Brush Seal w/ Anti-swirl Vanes

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Function of Retractable Seals at Start-up
Retractable Seal Clearances

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Brush Seal Performance
Source: NASA testing
Flow
Parameter
W
Pd
Pressure Ratio (Pu/Pd)
4 KE Laby Seal 0.5 mm Clearance
(NASA Report CR-135307)
4 KE Laby Seal 0.25 mm Clearance
(NASA Report CR-135307)
4 KE Laby Seal 0.18 mm
Clearance
(AIAA Paper 95-2763)
Typical Brush Seal Data
5X
8X
17X

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Seal Wear Over Time
0 5 10 15 20 25
Years
ΔMW
OEM Style Seals SMART Seal
OEM Style Seals
Installed OEM Style Seals
Replaced
SMART Seal Installed
Outage
Outage
SMART Turbine Seals
A custom engineered package of EthosEnergy sealing products
that when combined provide the best sealing system possible,
yielding significant operational improvements

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Blade Tip Seals
Another area for potential improvement is the blade
tip seals, which control steam leakage between the
stationary diaphragm and rotating blade

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The Brush Tip Seal applies EthosEnergy’s brush technology at the blade tip
Features
• Integrated flexible and compliant metallic brush element
• Improved leakage control over OEM design
• Reduced clearance for improved sealing effectiveness 0.02”/.508mm clearance
• Minimize seal wear during all operating periods – must be paired with retractable
packing
SMART Seals - Brush Tip Seals

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Typical GE Style Inlet Sealing System

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EthosEnergy upgrades HP inlet pipe sealing
Features
• Engineered coefficients of thermal expansion for seal rings
• Rings are in a loose condition at ambient temperature
• Super-alloys resist oxidation
• Pipes and bores are machined on-site as necessary to ensure roundness
• Maintains reduced leakage path during extended operation and simplifies turbine
maintenance, outage after outage
SMART Seals – Articulated Inlet Seals

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Configuration @ Ambient During Installation
Configuration While Running
Easy Installation & Resistance to Oxidation
EthosEnergy High Efficiency Inlet Seals

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+ Inner casing joint leakage is typically
caused by insufficient joint clamping force
and casing distortion during operation
+ Indicators
• Loose nuts on inner casing
• Threads, inner casing or studs, are
damaged
• Distortion of joint at mid-span area
• Decrease in HP section efficiency
• Apparent increase in IP section
efficiency
+ This condition is common to turbines with
opposed flow HP-IP sections
+ Unit heat rate and output are significantly
impacted with the joint in the open
condition
Horizontal Joint Leakage

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EthosEnergy’s solution upgrades inner casing horizontal joint sealing
Features
• Improved fastener material and design
• Design allows for higher preload and increased clamping force on joint
• Sustained clamping force between overhauls on the upper and lower halves of casing
SMART Seals – Joint Leakage Solution

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+ Age of turbines
+ Distortion
+ Dishing
+ Modifications
+ Maintain proper clearance
Why Custom Fit Seals?

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+ Removal
+ Pre-Measurement (current status of components)
+ Inspection (recommendations)
+ Installation (custom fit)
+ Onsite CNC Mill and Lathe equipment
+ Technical Direction
Available Services

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+ Ethos Energy offers removal of packing rings and spill strips.
+ Removal can be done in conjunction with a Pre-measurement
+ Free up millwrights to work on other items, potential to reduce overall turbine schedule.
+ Onsite or at EthosEnergy shop
+ Onsite inspections map wear relative to component location.
+ Range of repairs from a simple clean and re-sharpen, rebuild, to complete replacement.
+ Dimensional inspection results and recommendations provided to customer
Removal and Inspections

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+ Ethos Energy technician arrives onsite with a Pre-measurement kit.
+ Record critical dimensions on seals
+ Perform reversals as needed
+ Inspect holders and rotors for mechanical damage, erosion, corrosion, and
distortion assessment.
+ Relay data to engineering for custom manufacturing drawings
+ Manufacture with axial shifts or elliptical if required
Pre-Measurement

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Pre-Measurement
Measure each holder in 10
locations to identify any possible
distortion or dishing problems
Measure all rotor diameters where
packing rings and spill strips are
located

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Installation
+ Installation of conventional and SMART seals.
+ Portable CNC mill capable of cutting radiuses as well as all the tools
required to perform the installs.

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+ Onsite arrival time is scheduled by determining the rotor in date so
that the installation will be completed the same day as the rotor in
date.
+ Packing rings are measured for proper butt gap, end slots, pin slots,
and diametrical clearances. All machining is done on the turbine deck
to avoid possible delays caused at assembly time.
Installation

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+ Installations can include adjustments for component miss-alignment
to ensure a turn key approach.
+ Ethos Energy technicians will stay on site until the rotors are set. This
allows for charting of the rotor with the customer to ensure all
clearances are acceptable. Any concerns with radial clearances,
component miss-alignment and axial clearances can be addressed at
this time.
+ A copy of the installation data is given to our customer for their
outage records
Installation

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+ Shaft Seals
• 1%-2% heat rate
• 2%-3% output
+ Tip Seals
• ½% - 1% heat rate
• 1%-2% output
+ Snout Rings
• ½% - 1% heat rate
• 1%-2% output
Benefit Totals:
+ 2% - 4% Heat Rate Improvement
+ 4% - 7% Output Improvement
Typical Sealing System Upgrade Benefits:

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Retractable Brush Seals after
3 Years of Service

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Brush Seal After 2 ½ Years…and 6 Years

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Rotor Surface Condition

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Retractable Brush Seals After 8 Years

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+ 511 MW GE G2 opposed flow HP/IP machine
EthosEnergy Energy Package Case Study

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+ 511 MW GE G2 opposed flow HP/IP 2 double flow LP machine
+ Energy Package Implemented
• EthosEnergy SMART Turbine Seals
- Retractable seals, Retractable brush seals, Brush tip seals, Articulated snout rings, Horizontal
joint upgrade, custom installation
• Steam Path Repairs
- Nozzle and diaphragms
- Replace one stage of blades
• Open/Close Services
• Steam Path Audit and Performance Evaluation (3rd party evaluation)
EthosEnergy Energy Package Case Study

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+ 511 MW GE G2 opposed flow HP/IP 2 double flow LP machine
+ Performance Benefits Realized
• 3% improvement in gross turbine heat rate cycle
• HP efficiency improved by 8.3%
• IP efficiency improved by 3.1%
+ All completed during a normal outage window
EthosEnergy Energy Package Case Study
Turbine Recovery By Section DPower kW DHeat Rate Btu/kWh
HP 16,096 212.8
IP 2,468 49.5
LPA 674 13.5
LPB 1,538 30.8
Total 20,776 306.6

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‘What’ is EthosEnergy ?
+ Gas Turbine OEM (Fiat / Westinghouse)
+ Gas Turbine Services – Heavy Industrial
+ Steam Turbine Services
+ Generator Services
+ Compressor Services
+ Transformer Services
+ Gas Turbine Services
Heavy Industrial, Light, Aero
+ Steam Turbine Services
+ EPC and Fast Track Projects
+ Construction Site Services
+ Facility O&M
+ Auxiliary and Pump Overhaul
+ Wood Group P&W JV
Wood Group Siemens
+ OEM Intellectual Property Support

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SMART Seal Evaluation
+ If customers provide the following additional information EthosEnergy
can review their turbine and propose a SMART Seal package and
performance estimates
+ NEED
• Cross-section drawing
• OEM parts list
• Heat Balance
+ Helpful
• Clearance Drawing
• 1st stage shell pressure curve
• Piping diagram
• Outage duration
• Past performance testing data
Contact:
Jay Stritter
Jason.stritter@ethosenergygroup.com
(281) 546-2904 (cell)

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Power Plant Drivers After SMART
Seal
Installation
Unit Production
cost ($/Btu)
Lower
Unit Efficiency
(Btu/kW-HR)
Improved
Availability and
Reliability Improved
Improved
Emissions Lowered
Capacity (MW) Increased
Future maintenance
cost
Lower
Going forward cycle
costs ($/kWh)
Lower
Customer Benefits from SMART Seals
Questions?