H&I. Condenser Performance Monitoring

March 29, 2018 | Author: Rajendran Srn | Category: Heat Exchanger, Heat Transfer, Steam, Heat, Thermodynamics


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Description

1Power 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 . 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 . a thorough understanding of the pump operation is needed.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. 11 Design Data Entry Condenser Spec Sheet Cooling Tower Spec Sheet . 12 Design Data Entry . 13 Design Data Entry . Data Capture HISTORIAN DOWNLOAD . both net and gross  Cogen Steam if applicable  Ambient Temperature  Hotwell Temperature .What operational data points are needed?  Basic points  Plant load  Steam Load  Condenser Back Pressure  Cooling Water In and Out Temps  Heat Rate. if cooling tower and no Wet Bulb  Each GT MW output. but not typically brought back to historian .or at least a % expected  Wet Bulb. which is captured by the unit.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.What operational data points are needed?  “Would like to have” points  Cooling Water In and Out Pressures  Extraction Steam.if cooling tower  Humidity %. 17 Historian Download Setup . 18 Historian Data Download . Data Import UPLOADING HISTORIAN DATA . 20 Accessing the CPMT and Importing Data . Data Review GRAPHING TOOLS AND DASHBOARD . 22 Graphing Options . 23 Dashboard . A Discussion about Condenser Performance WE HAVE THE DATA NOW WHAT? . What parameters do we care about and why? Air Steam CW Out CW In Condensate . 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 LMTD Temperature  Steam Temperature Constant TTD ITD TR Distance Down Tube  . Performance Definitions and Calculations Industry standard but very much misunderstood  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 . 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.5 psia = 1304 btu/lb 2. lower BP in condenser.0 inHg = 1111 btu/lb Additional 6 btu/lb to Turbine and MW generation at lower BP .5 psia = 1304 btu/lb 101.0 inHg = 1105 btu/lb 3. more BTU’s transferred to Turbine 101. Performance Consequences – Inlet Water Temp  Many don’t consider this when discussing current operating BP  Inlet Water Temp dictates condenser performance  Assuming constant TR.2 inHg increase in BP . every 2°F can mean as much as a 0. 34 Effect of Cooling Water Inlet Temperature Cooling Water In Temp vs.50 1.00 3.00 1.00 50 60 70 80 90 Cooling Water Inlet Temp f *Assumes 20°F TR and 6°F TTD 100 110 .00 2. BP* Back Pressure inHg 4.50 4.50 2.50 3. 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 Scale/Foulant Resistance = Rfoul Condensate Resistance = Rcond Tube Resistance = Rtube Water Resistance = Rwater U = 1/(Σ Resistances) . Important Considerations PITFALLS OF CONDENSER MONITORING . 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.Common Obstacles  Cycling plants difficult to monitor. but with a properly set up Thermal Kit and filtering. not what you would like to happen  Check multiple parameters to make sure they correlate  Make sure you understand plant operation/dispatch . start by filtering the data to the condition desired  Remember. and date all at the same time to really drill down to what you are looking for . inlet water temp.Analyzing Data  Be patient  Look at all parameters before starting to form a conclusion  Because it is important to compare like conditions. you can filter on many parameters at once  For instance. you can filter plant load. CASE STUDIES . Case #1.Vacuum Pump Seal Water . Case #2.Bio-Surfactant Addition Mechanical Cleaning Surfactant Addition . Case #3.Air In-leakage . DISCUSSION .
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