Front Range Power Plant: Air Cooled Condenser Tom Cook, PE Colorado Springs Utilities, Operating Engineering Group Air Cooled Condenser User Group: October 2018
Supply Reliability (1,149 MW Total) Martin Drake Power Plant Coal #6-77 MW #7-131 MW Front Range Power Plant Natural Gas Combined cycle 480 MW Birdsall Power Plant Natural Gas 55 MW Contracted Solar Facilities AFA 5.4 MW Solar Gardens 4 MW CSR 10 MW CSU Hydro Electric 35.2 MW (6 units) Nixon Power Plant Coal #1-208 MW Natural Gas #2 & #3 - CT s, 60 MW Contracted WAPA Hydro ~ 83MW
Agenda Description Performance Monitoring Maintenance / Inspections Operating Practices
ACC Description Plant Design Parameters 480 MW 100 gpm max water use ACC Design Conditions 1,266,468 pph 1081 Btu / lb 3.57 in HgA 80 F air temp 12.01 psia barometer 40 two-speed fans 8 rows
ACC Description Row 8-5
ACC Description Permanent Ladders / Platforms
ACC Description Permanent Ladders / Platforms
ACC Performance Monitoring 1,600,000 Steam Flow vs Amb Temp, F Fans in Fast 1,400,000 Manufacturer Performance Curves Steam Flow, lb / h 1,200,000 1,000,000 800,000 Backpressure, in HgA 600,000 2 3 4 5 6 7 Cold Weather Operations 400,000 20 30 40 50 60 70 80 90 100 110 Ambient Temperature, F 1,400,000 Steam Flow vs Rows in Service 1,600,000 Steam Flow vs Amb Temp, F Fans in Fast Steam Flow, lb / h 1,200,000 2 3 4 5 6 7 1,000,000 8 800,000 600,000 400,000 200,000 Cold Weather Operations 0-30 -25-20 -15-10 -5 0 5 10 15 20 25 30 35 Ambient Temperature, F Rows in Service Steam Flow, lb / h 1,400,000 1,200,000 Amb Temp, F 1,000,000 50 60 800,000 70 80 600,000 90 100 400,000 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 Back pressure, in HgA
ACC Performance Monitoring Self-Developed Performance Curves 15 to 80 fan count, where 0 = fan off 1 = fan on slow 2 = fan on fast 6 Defined at new & clean Used for trending 80 Fan Count 40 fans fast Mfr supplied curves applicable only for 40, 50 & 80 fan count. Backpressure, in HgA 5 4 3 2 1 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 Am b T F 100 90 80 70 60 50 40 30 ST Exh Flow, kpph
ACC Performance Monitoring Water washing lowers the Actual Expected Difference Good 1.0 0.9 Mfr Front Range ACC: Actual - Expected Back Pressure New Curve 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 Actual - Expected BP, in HgA
ACC Performance Monitoring Key Performance Indicators Actual vs New & Clean Backpressure Air Side differential (T cond T air removal ) (by row) Ambient conditions (Baro, RH, Wind Speed / Dir Fan Aux Load (kw / kpph) Fan static pressure (future consideration; Hi/Low, before/after wash) Other KPI s SJAE, GSC duty & Temp rise (SJAE nozzles replaced at ~9 years) Subcooling Performance-Based Recommendations Water wash annually (0.4 to 0.7 in HgA improvement) Helium leak tests Careful with using inlet air temperature RTD s (air recirc bias) Water-washes Contractor supplied wash skid. (OEM skid / rig insufficient quality)
ACC Maintenance / Inspections Inspection Summary LP turbine rotor deposits Ductwork & Piping (passivated, free of significant iron removal, FAC evidence) Standing water / rusting in the valley walkways Structural review
ACC Maintenance / Inspections IP Drum steam separator flowassisted corrosion
ACC Maintenance / Inspections Stationary Vane Cracks
ACC Maintenance / Inspections Stationary Vane Cracks Crack at weld in turning vane support
ACC Maintenance / Inspections Center trough between tube entry with standing water and rust Tube Connections Historical: 1 tube repaired, 1 small crack. Found during Helium leak testing
ACC Maintenance / Inspections Tube inlets; area around black scale in tubes is FAC
ACC Maintenance / Inspections Steam bypass on top of exhaust duct, FAC at wall impact point FAC on support pipe (shiny spot) at entry to lower distribution duct
ACC Maintenance / Inspections Oil Filter Cart 2 elements: 6 & 12 µ Moved every 2-3 days 10 gph
ACC Maintenance / Inspections Fan Gearbox Oil Changes Changed oil based on oil sample results Changing from Amsoil to Mobil 632 65% 60% 55% ACC Fan Service Factor Gearbox Oil Testing Particulate based focus 50% 45% 40% 35% 30% 25% 20% Max = 2.5 x Min K22 K32 D33 D43 D23 D73 D63 D53 K52 D13 K62 K72 K12 K82 K42 K24 K34 D83 K44 K54 K64 K74 K84 K11 K21 K31 K14 K41 K51 K61 K71 K81 K15 K25 K35 K45 K55 K65 K75 K85 Fan Gearbox Oil Filtering Duty cycle basis is a consideration 2 Carts in service ~3 days per cell
ACC Maintenance / Inspections Condensate Side-stream filter start-up iron throw sends magnetite layer to HRSG used during full-plant start ups Condensate pump suction strainers not clogging (with current operation) Lesson learned: Don t use a silicabased filter element
ACC Maintenance / Inspections Upgrades / Modifications Built in ladders & platforms to upper ACC ducts Heat trace condensate tank level sensors Insulated & heat traced loop seals Hogger isolation valves: reduce atmospheric leakage into ACC. Oil Storage Deck
ACC Maintenance / Inspections Fan Blade Inspections New Rivet Installation: Engineered metric rivets 6x12 mm UNI 9200-A, DIN 7337-A Note: Blades are fixed pitch Warning: Blades drop with no alarms / warnings
ACC Operating Practices Freeze Protection Know design # of rows vs steam flow Verify controls / operations Thawing cells Walk the rows (thermal scans if freezing is suspected) Air Removal Automatic burp cells / rows (was manual) Helium leak testing (annually) Monitor T (Condensate T Air Removal T < 20 F) DA non-condensable-gas vent directed back to the ACC
ACC Operating Practices Walkdowns Weekly row walks Motor vibrations: on routes (looking into a vibration trip switch & potentially on-line vibration monitoring) Chemistry O 2 Control: hydrazine then carbohydrazide then nothing. O 2 is maintained 10-20 ppb by the deaerator Chemistry / corrosion. Some surface corrosion. Very minimal Internal Inspections. Every 2-3 years. Watch IP Drum Steam separators (replaced in 2010, no issues since)
Thank You What Questions May I Address? Commitment - Excellence Courage Persistence Honor Joy Ethical Respect Dignity Patience Collaboration Skilled Constructive Solution Engaging Positive Learning Giving Admiration Leading Aligned Focused Practical Humble Commitment - Excellence Courage Persistence Honor Joy Ethical Respect Dignity Patience Collaboration Skilled Constructive Solution Engaging Positive Learning Giving Admiration Leading Aligned Focused Practical - Humble Commitment - Excellence Courage Persistence Honor Joy Ethical Respect Dignity Patience Collaboration Skilled Constructive Solution Engaging Positive Learning Giving Admiration Leading Aligned Focused Practical - Humble Commitment - Excellence Courage Persistence Honor Joy Ethical Respect Dignity Patience Collaboration Skilled Constructive Solution Engaging Positive Learning Giving Admiration Leading Aligned Focused Practical - Humble
Contact Information Colorado Springs Utilities www.csu.org E. Thomas Cook, PE Colorado Springs Utilities Engineer Managing, Operating Engineering Group tcook@csu.org