Embed Size (px)
Citation preview
Getting to Know Your Unit’s Capabilities
A Case Study in Unit Parameters & Performance
Nick Miller – Colorado Springs UtilitiesChad Swope – Burns & McDonnell
May 21, 2019
Agenda
• Introduction to Colorado Springs Utilities• Scope of Study• Unit Parameter Analysis• Benchmarking• Cycling Evaluation• Conclusions
Company Overview ► Founded in 1924► Municipal Utility supplying:
• Electricity• Water• Wastewater• Gas
► Employees 1,837► Electric Service Details
• Service Area 475 sq. miles• Peak Generating Capacity 1,049 MW• Peak Load 930 MW
Electric Generation Units► Martin Drake Unit 6
• PRB Coal-Fired Steam Generation Unit• In Service 1968• 77 MW Net
► Martin Drake Unit 7• PRB Coal-Fired Steam Generation Unit• In Service 1974• 130 MW Net
► Ray Nixon Unit 1• PRB Coal-Fired Steam Generation Unit• In Service 1980• 195 MW Net
► Ray Nixon Unit 2-3• Natural Gas Simple Cycle Gas Turbine• 30 MW Net each
► Front Range Power Plant• Natural Gas Combined Cycle• In Service 2003• 480 MW Net
► Birdsall Units 1-3• Natural Gas-Fired Steam Generation Units• U1 = 16 MW; U2 = 16 MW; U3 = 23 MW
► Manitou Units 1-3• Conventional Hydro• U1 = 2.5 MW; U2 = 2.5 MW; U3 = 0.46 MW
► Ruxton• Conventional Hydro• 1 MW
► Tesla• Ponded Hydro• 28 MW
► Cascade• Conventional Hydro• 0.85 MW
Purchase Contracts► Western Area (Loveland Area Projects)
• 61 MW Summer / 57 MW Winter
► Western (Salt Lake City Integrated Area Projects)• 15 MW Summer / 60 MW Winter
► Wind• 2 MW
► U.S. Air Force Academy Solar• 5.25 MW
► Solar Garden Pilots• 2 MW
► Solar Garden Tariff• 2 MW
Additional Solar Generation Coming
Planned: 95 MW by 2020Anticipated: 150 MW by 2023
Study Scope – Unit Parameters and Performance Evaluation
► Unit Parameter Analysis• Startup Times• Startup Costs• Temperature Decay Times• Ramp Rates• Minimum Load
► Performance Testing• Develop Heat Rate vs. Output Curves
► Benchmarking► Cycling Analysis
• O&M Impacts • Inspection Recommendations
► Nixon Full Load Testing• HVT Testing
Unit Parameters Analysis
Startup Times
Ramp Rates
y = 2.7927x + 162.63
150.00
160.00
170.00
180.00
190.00
200.00
210.00
220.00
0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00
Gross Outpu
t, MW
Minutes
Ramp Rate
► Ramp between Minimum Load and Maximum Load• Excluding time to get additional
mills online
► Identified need for controls tuning
Typical Turndown Limitations
Flame Stability
Pulverizer / Mill Turndown
Gas Temperature into Emissions Controls Equipment
Economizer Steaming
Superheater / Reheat Temperature Control
LP Steam Turbine Exhaust Conditions
Boiler Feed Pump Turbine Turndown
Feedwater Heater Drain Level Control
Turndown Limitations► Tune / automate systems for low load operation
• Combustion optimization Tune secondary/primary air to burners Strategically selecting burners utilized
• Use ignitors to maintain flame stability
► Install economizer bypass• Maintain flue gas temperatures into FGD• Large Particle Ash (LPA) Screens
► Operate steam coil air heater► Install steam coil flue gas heater at FGD outlet
Economizer Bypass
Performance Testing – Heat Rate Curves
10,500
11,000
11,500
12,000
12,500
13,000
30 40 50 60 70 80 90
Cor
rect
ed N
et u
nit H
eat R
ate,
Btu
/kW
h (H
HV
)
Corrected Net Output, MW
Design NUHR Historical NUHRTest Corrected NUHR Test Corrected NUHR Trend
► Ray Nixon Unit 1 ► Martin Drake Unit 6
Benchmarking
Benchmarking
►Compare against Peer Group• Unit Parameters• Thermal Performance• O&M Costs• Cycling
► Identify key areas for improvement
Benchmarking
Benchmarking
Benchmarking
Benchmarking
Benchmarking Insights
Focused Benchmarking:Unit operational
parameters, impacts of cycling, and unit flexibility.
Technical Oriented:
BMcD Experience in the Industry to understand the
“Why?”
Intuitive Dashboards:
Utilize Power BI which is easy to use and readily
available.
Cycling Impacts
► Aspects of Cycling• Startup / Shutdowns• Load Following
Component Damage Mechanism
Boiler / HRSG Tubes
Tube failures due to overheating caused by either temperature imbalances at low flow (min load operation) or when heat flux increases faster than flow (ramping)Corrosion due to flue gas temperatures dropping below acid dew point (min Load operation)
Headers Ligament cracking due to thermal fatigueStub tube cracking due to thermal cyclesFlow Accelerated Corrosion in Economizer
Attemperators / Piping
Thermal fatigue of downstream piping due to overspray, improper atomization, or leaksSpray nozzle failures due to on‐off cyclesThermal fatigue at hanger attachments
Combustion Turbines
Rotor and blade attachment fatigueCombustor can crackingTBC lossBlade seal wear
Steam Turbines Rotor and blade attachment fatigueErosion of first stage HP/IP blades due to exfoliation from the boilerErosion of LP LSB due to water droplet impingement
Impacts of Cycling
Impacts of Cycling► Startup / Shutdown Cycles
• Convert to equivalent operating hours• Estimate remaining component life• Estimate replacement/repair cost
Impacts of Cycling
Dispatch Scenarios Operating Hours EHS
Scenario 1 7,215 7
Scenario 2 6,715 17
Scenario 3 6,215 27
Scenario 4 5,715 37
Scenario 5 5,215 47
Dispatch Scenarios Operating Hours EHS
Scenario 1 7,220 10
Scenario 2 6,720 20
Scenario 3 6,220 30
Scenario 4 5,720 40
Scenario 5 5,220 50
Dispatch Scenarios Operating Hours EHS
Scenario 1 7,442 25
Scenario 2 5,974 75
Scenario 3 5,394 125
Scenario 4 5,043 175
Scenario 5 4,795 225
► Operating Profile• Cumulative operating hours / starts• Sensitivities around future operating profile
Ray Nixon Unit 1 Martin Drake Unit 6 & 7 Front Range Power Plant
Impacts of Cycling
►Load Following• Ramping between minimum continuous operating load and maximum load Significant Load Following >17.5% of gross capacity
Load Following Cost ($/MW) 25th Percentile Median 75th Percentile
Coal‐Fired Steam Unit $2.18 $3.82 $4.39
Source: Power Plant Cycling Costs. NREL, Golden, CO.
Impacts of Cycling
►Projected O&M Cost• Calculated based on assumed operating scenarios and load following
Example Combined Cycle UnitExample Coal Unit
Impacts of Cycling►How Do We Minimize O&M Cost Impacts?
• Reduce Minimum Operating Load Reduce Startup/Shutdown Cycles
• Keep Unit Hot Longer ST Warming Blankets Aux Boiler Steam Sparging Stack Dampers
• Minimize Dissimilar Metal Welds• Establish NDE Inspection Plan to identify cracking• Operate in sliding pressure mode• Regularly Inspect Attemperator Nozzles and Valves
Conclusions► Understand your unit’s capabilities
• Can the capabilities be improved through operational changes or capital projects
► Understand how your unit compares to other similar units• Benchmarking can be key to identifying low hanging fruit for improving operational
flexibility and reducing O&M costs► Understand the O&M impacts of cycling
• Ensure that you are properly budgeting for future O&M spending based on new operational profile
Thank You!
Chad SwopeUtility Consulting
Nick MillerPrincipal Engineer
![Live-View Remote RM-LVR2 · [7] How to use Getting Started Setting the date and time Setting the date and time When using for the first time or after updating of this unit’s software,](https://img.pdfslide.us/doc/110x75/5e445653b9f4e72cd8417041/live-view-remote-rm-lvr2-7-how-to-use-getting-started-setting-the-date-and-time.jpg)
