h&i. condenser performance monitoring
DESCRIPTION
Condenser Performance MonitoringTRANSCRIPT
1
Power Plant Performance Monitoring
Indonesia Customer Seminar
June 13 & 14 2012
Jakarta Indonesia
Why monitor Condenser Performance?
It is where the money is made or lost
Optimize cooling water program
Identify mechanical issues such as with air-removal systems
What is a Condenser and how does it work?
Nothing more than a heat exchanger
Condenses steam by transferring heat to cooling medium
The better the heat transfer rate, the better the vacuum, the more efficient the Steam Turbine/Plant
What is Nalco’s Condenser Performance Offering?
Condenser Performance Monitoring Tool (CPMT)
Captures plant data, as well as Trasar data
Compiles information, performs calculations, generates Dashboard for reviewing with customer
So how does the Condenser Performance Monitoring
Tool work?
Gathers the plant’s raw data for the key parameters
Uses these to make necessary calculations
Calculations provide quantitative information to trend condenser performance
So how does the Condenser Performance
Monitoring Tool work?
Graphs provide big picture view of condenser performance and allow for comparison of the key parameters
Most important is that it allows for filtering of data to compare like-for-like conditions
In the end the tool provides an accurate method of troubleshooting and identifying areas of improvement
What is required by the plant?
Provide the proper design documentation
Inform the Nalco Representative of any changes that have been or will be made to the Cooing or Condenser Systems
Help with set up of the Historian Download sheet
What is required by the rep?
Modification of the tool to fit plant’s needs
Periodic download of data from customer computer
Migration of that data to the tool
Analysis of that data with customer
DESIGN DATA ENTRY
What design data is needed?
Condenser
Design thermal and flow balance
Typically found in the Condenser Spec Sheet
Cooling
Cooling Tower spec sheet if applicable
For Once-Through’s, a thorough understanding of the pump operation is needed, particularly number of pumps for each season
Thermal Kit
Extremely valuable in comparing actual to design under all conditions
Contains information regarding Back Pressure vs Inlet Water Temperatures, as well as flow and heat load on the condenser
Design Data Entry
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Condenser Spec
Sheet
Cooling Tower
Spec Sheet
Design Data Entry
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Design Data Entry
13
HISTORIAN DOWNLOAD
Data Capture
What operational data points are needed?
Basic points
Plant load
Steam Load
Condenser Back Pressure
Cooling Water In and Out Temps
Heat Rate- both net and gross
Cogen Steam if applicable
Ambient Temperature
Hotwell Temperature
What operational data points are needed?
“Would like to have” points
Cooling Water In and Out Pressures
Extraction Steam- or at least a % expected
Wet Bulb- if cooling tower
Humidity %- if cooling tower and no Wet Bulb
Each GT MW output- if HRSG
Fuel usage for all applicable systems
Important to note that we can pull anything into the tool
This allows us to trend other plant operations with the Condenser and Cooling Tower Performance
An example would be the 3D Trasar or NCSM data, which is captured by the unit, but not typically brought back to historian
Historian Download Setup
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Historian Data Download
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UPLOADING HISTORIAN DATA
Data Import
Accessing the CPMT and Importing Data
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GRAPHING TOOLS AND
DASHBOARD
Data Review
Graphing Options
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Dashboard
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WE HAVE THE DATA NOW
WHAT?
A Discussion about Condenser Performance
What parameters do we care about and why?
Steam
CW In Condensate
CW Out
Air
What are some key indicators of Condenser
Performance?
Back Pressure (BP)
Heat Rate (HR)
Air-In-leakage
Cleanliness Factor (CF%)
Initial Temperature Difference (ITD)
Terminal Temperature Difference (TTD)
Temperature Rise (TR)
Log Mean Temperature Differential (LMTD)
Performance Definitions and Calculations
ITD – temperature difference between the Steam Temp and the Inlet Water Temp
Stm – CWin
Can be key in identifying inlet water/cooling tower issues
TTD – temperature difference between the Steam Temp and the Outlet Water Temp
Stm – CWout
Indication of overall heat transfer and performance
Performance Definitions and Calculations
TR – temperature difference between CWout and CWin
Indication of how much heat was picked up by cooling water
Can be a good indication of fouling
LMTD - logarithmic average temperature difference
TR / ln(ITD/TTD) (for counter current)
In essence is the average temperature change across the tube bundle
Performance Definitions and Calculations
Distance Down Tube
Tem
pera
ture
TTD
ITD TR
Steam Temperature Constant
LMTD
Performance Definitions and Calculations
CF% = Ua / Ud
Ua = Q / A * LMTD
Ud = Ui * FL * F1 * F2
FL = Steam Load Factor
F1 = Inlet Water Correction Factor
F2 = Tube Gauge Correction Factor
Ui = Ideal Heat Transfer Coefficient
Industry standard but very much
misunderstood
What are some key aspects of Condenser Operation?
Performance Consequences- Turbine Efficiency
Efficiency of Turbine determined by BTUin and BTUout
Lower BTUout value = more btu’s transferred to Turbine
Therefore, lower BP in condenser, more BTU’s transferred to Turbine
3.0 inHg = 1111 btu/lb
101.5 psia = 1304 btu/lb
2.0 inHg = 1105 btu/lb
101.5 psia = 1304 btu/lb
Additional 6 btu/lb to Turbine and MW generation at lower BP
Performance Consequences – Inlet Water Temp
Many don’t consider this when discussing current operating BP
Inlet Water Temp dictates condenser performance
Assuming constant TR, every 2°F can mean as much as a 0.2 inHg increase in BP
Effect of Cooling Water Inlet Temperature
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1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
50 60 70 80 90 100 110
Back P
ressu
re i
nH
g
Cooling Water Inlet Temp f
Cooling Water In Temp vs. BP*
*Assumes 20°F TR and 6°F TTD
Performance Consequences – Air In-Leakage
Air In-leakage a significant contributor to degradation in condenser performance
Typically not monitored on-line
Typically not well understood
Blankets tubes preventing heat transfer Air Resistance
= Rair
Condensate
Resistance = Rcond
Tube Resistance
= Rtube
Scale/Foulant
Resistance = Rfoul
Water Resistance =
Rwater
U = 1/(Σ Resistances)
PITFALLS OF CONDENSER MONITORING
Important Considerations
Common Obstacles
Cycling plants difficult to monitor, but with a properly set up Thermal Kit and filtering, can be accomplished
The data is only as good as the tools used to collect it
Bad probes
Bad location
Not sent back to the historian
All play a role in poor data collection
Seeing what you want to see
Analyze the data, not what you would like to happen
Check multiple parameters to make sure they correlate
Make sure you understand plant operation/dispatch
Analyzing Data
Be patient
Look at all parameters before starting to form a conclusion
Because it is important to compare like conditions, start by filtering the data to the condition desired
Remember, you can filter on many parameters at once
For instance, you can filter plant load, inlet water temp, and date all at the same time to really drill down to what you are looking for
CASE STUDIES
Case #1- Vacuum Pump Seal Water
Case #2- Bio-Surfactant Addition
Mechanical
Cleaning
Surfactant
Addition
Case #3- Air In-leakage
DISCUSSION