This is a summary of my contributions as a Duke Energy mechanical engineering Co-op student.

1. Shane Mathew
Fossil Hydro Operations
Engineering Co-op Program
12/03/2019

2. About Me
■ University of South Florida
– Junior
– Mechanical Engineering
– May 2021
■ First Rotation with Duke Energy
– Bartow CC
2

3. Co-op Session Information
■ Bartow Combined Cycle Plant
– St. Petersburg, FL
■ Manager: Clide Forte
■ Mentor: Ron Major
 4-on-1
 Able to run simple or combined cycle
-Rare plant with two stacks per CT
 Auxiliaries such as PAG, Evap Coolers,
and Duct Burners add over 110MW and
are available year round

4. Project List Overview
■ Heat Recovery Steam Generator (HRSG)
Inspection & Training with Vogt Power
■ Permanent Tank Farm Sump Pump Installation
■ Steam Valve Replacement- Thermodynamic
Analysis
■ Discharge Water Canal Permanent power
■ Closed Cooling Water (CCW) Loss Mitigation
4

5. CCW Fundamentals
■ Plant equipment are exposed to high heat that,
if left uncooled, keep giving off heat, hence the
importance of an external cooling agent such
as CCW
■ The heat absorbed by CCW from the
equipment cycles through the CCW heat
exchangers where the heat is given off to the
cool water from Tampa Bay via the circulating
water system
■ The CCW system has a head tank that ensures
adequate suction head to the pumps and
accounts for thermal changes in system volume
■ Demineralized water is the makeup of CCW

6. Problem
■ The CCW head tank level loss
rate has substantially increased
since September 2017
■ The average time period between head
tank refills
– November 2016: 9 days
– November 2017: 20 hours
– November 2018: 11 hours
– November 2019: 9.5 hours
■ The average gallons per minute water lost over this time period has
increased to 1.4 gallons per minute (gpm), or about 2,000 gallons per
day.
■ The source of the loss is unknown and not visually apparent

7. Project Objective
■ Locate the source of CCW losses and mitigate
– This will reduce the costs of refilling the head tank and return the
closed cooling system to normal operation with normal losses
■ 0.02 gpm is the target gpm loss rate- according to historical data this is
considered a normal loss rate

8. Solution A: System Isolation
■ Equipment in the power block receiving CCW were strategically tested by closing the
supply and return CCW valves separately for 24 hours
■ After 24 hours, the valves are opened back up and the next section is isolated while
head tank level data is analyzed
■ If the head tank level ceases to
decline at the current loss rate,
then the individual system
closed off may be the sole or
contributing factor to CCW loss
and will be repaired after further
evaluation

9. System Isolation Scope
■ The units tested include:
– vacuum priming skid
– condenser vacuum skid
– chemical labs
■ These units were of special
interest due to the fact that
there is piping path for CCW
to flow without falling to the
ground

10. System Isolation Results
■ The resulting loss rate
after each isolated test
remained the constant
1.4 gpm loss
■ Thus, losses above
ground were ruled out
and it was concluded
the loss is likely below
ground

11. Solution B: Acoustic Testing
■ The CCW flow path was analyzed on Navisworks and through Fusion design
drawings to scope the test path of underground piping
■ The Ultrasound Detection Equipment (UE) device was calibrated to 40 KHZ at
a sensitivity value of 70 to detect the underground leak
■ Acoustic testing was performed along the CCW routes around 4Alpha once
every foot distance

12. Acoustic Testing Results
■ A damp ground indication led to further investigation into the CCW
lines between 4Alpha and 4Bravo HRSGs. A slight uptick in sound
was detected near the site of the damp ground
■ After analyzing the path of CCW relative to the damp ground and
validating through PI that the loss rate has increased, the decision
was made to excavate at the site of a CCW joint between 4Alpha
and 4Bravo
■ The source of CCW losses was founded to be at the site of a
fractured pipe and repaired using a leak repair clamp

13. Leak Source
Repair Clamp

14. Project Challenges
■ System Isolation for underground CCW lines were not
possible due to an uninterrupted return line to the head
tank that could not be closed off
■ A different approach to underground testing had to be
researched
First option:
■ Flush the CCW system out, pressurize the pipes
with Helium using available vents, and monitor
above ground for helium hotspots using a helium
detector device
■ This would be labor intensive and at the time did not
fit the outage schedule
Second option:
■ Acoustic testing which was feasible and outage-
schedule friendly

15. Project Results/ Turnover
■ The loss rate for CCW is
currently at 0.01 gpm,
surpassing the goal of 0.02 gpm
■ This zero-loss rate has been
maintained since the day of
repair on 11/21/2019
■ Hence, the head tank level has
maintained 60’’ of CCW.
Frequent head tank level refills
are no longer required.

16. Project Budget and Cost Savings
■ Both system isolation and acoustic tests
required $0.00 in additional expenses
other than the labor costs to conduct
these tests
■ The expense of frequent refilling of the
head tank about 2.5x per day will be
averted for the foreseeable future

17. Project Auxiliary Benefits
■ Relieves environment of exposure to
Demineralized water
■ Due to the loss, corrosion inhibitor injections had
to be halted
– Corrosion inhibitors prevent damage of the piping
system from corrosion

18. Skills and Knowledge Acquired
■ Fusion
■ PI Processing
■ Heat Transfer Fundamentals
■ Multi-dimensional Problem Solving (There is always another
way)

19. Looking Ahead
■ Complete last 3 semesters at USF
■ Return for a second rotation
■ Pass FE exam Spring 2021
■ Graduate from USF May 2021

20. Questions?
20