epri's btfr program - ee publishers

© 2021 Electric Power Research Institute, Inc. All rights reserved.w w w . e p r i . c o m

Kent ColemanProgram Manager

Reliability Maintenance for Boilers and Associated PlantSouth AfricaDecember 7, 2021

EPRI’s BTFR ProgramBoiler Tube Failure Reduction

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© 2021 Electric Power Research Institute, Inc. All rights reserved.w w w . e p r i . c o m2

The Bad News

▪ Boiler Tube Failures (BTFs) continue to be a leading cause of forcedoutages in fossil power plants

▪ Tube failures have dominated the forced outage rate since reliability statistics have been kept in individual utilities

▪ BTFs can cost a utility in lost opportunity as well as O&M dollars….usually at the most inconvenient time



BTF Reduction Guidelines to Improve Fleet Availability –

The Good News▪ EPRI Boiler Tube Failure Reduction Program (BTFR) leads the industry in

reducing outages due to tube failures▪ Benefit

– Develops a systematic approach to reducing forced outages due to boiler tube failures

– Keeps units online producing power to meet system demands

– Allows for scheduling of manpower and equipment during scheduled outages

– Reduces or eliminates repeat tube failures

▪ Application– Demonstrates tools that can be applied to assist in the decision-making process

during forced outages

– Enables an understanding of the cost associated with tube failures

– Provides tools that allow for decisions on how long unit can continue to run once leaks are detected

– Develops a consistent approach to addressing and reducing tube failures



What is the BTFR Program

▪ A systematic approach to reduce forced outages resulting from boiler tube failures

▪ Provides tools to utilities to address boiler tube failures:

– Possible damage mechanism

– Probably root cause

– Immediate repairs

– Damage mechanism confirmation

– Longterm protective actions

Elimination of Repeat Failures



Approach to Reduce BTFs

▪ Proper documentation of tube failures including locations and root causes (trending failures, statistical analysis and justify tube replacements)

▪ Boiler inspections– Find damaged tubes– Perform condition assessment (take tube samples to be proactive) - plan for next

outage – Quality control at end of outage to ensure damaged tubes were repaired properly

▪ Proper documentation of “temporary repairs” so they can be replaced during next available outage

▪ Correct decisions on type of repair to make– Plant boiler tube failure reduction teams send samples and tube failures in for

analysis to determine root cause, remaining life, etc.

▪ Reliability groups - determine and schedule future boiler work▪ Implement EPRI’s Boiler Tube Failure Reduction Program



Key Resources

Volume 1: Fundamentals

Volume 2: Water-Touched Tubes

Volume 3: Steam-Touched Tubes

Report 3002010388 (Vol. 1-3) Report 3002018747


https://www.epri.com/research/products/000000003002010388



Formalized Integrated Boiler Tube Failure Reduction

(BTFR) Program

▪ EPRI initiated the BTFR program in 1985 to demonstrate that availability of fossil fired boilers could be significantly improved through a formalized BTFR program

▪ Initial program was very successful. ▪ 16 host utilities

– Improvements from 1.5 to 4.5% were demonstrated

▪ In 1996 EPRI published the “BTF Book” – Currently more than 70 organizations have implemented a formalized BTFR

program ranging in size from single plants to > 40,000 MW systems– Program Goal to reduce unavailability due to boiler tube failures to less than

1% (World Class)– Latest Version, Report 3002010388 (Vol. 1-3), 2018




Update of Boiler Tube Failure Reduction Program Guidance

▪ Guidance for developing/enhancing a BTFR program

▪ Considers changes in power generation industry since previous version (2006)

– Operating philosophy change from baseload to cyclic operation

▪ Renewable energy deployment

▪ Market demands/system conditions

▪ Increase in combined cycle power plants

– Near-term retirement of coal-fired power plants

– Generating plant staff with less time in the position

– Reduced capital expenditures

▪ Industry survey on boiler tube failures

▪ Multiple case studies

Report 3002018747



BTFR Program

▪ Overall Goal – improving or maintaining a certain level of boiler availability – no longer a specific target

▪ Strategies

– Improve boiler availability by reducing number of BTF events

– Improve boiler availability by reducing consequence of BTF events

– Goal to still eliminate repeat failures

▪ Tactics provided that are effective in implementing the above strategies



Implementing a BTFR Program – 3 Stages

▪ Recognition– Self-assessed discovery process

▪ Gather industry and/or in-house data – acknowledges performance compared to industry ‘average’

▪ Realization of economic costs often a key in recognizing need

– BTFR program itself offers an effective mechanism to track costs

▪ Correction– Performing tasks that move boiler towards stated goals

– Formation/implementation/modification of BTFR program

▪ Continuation– Implementing practices to maintain desired boiler availability for indefinite period

– Program benchmarking to evaluate efficacy



New BTFR Metric: Equivalent Unavailability Factor (North America)

▪ Changed from EAL (equivalent availability loss) to EUF to better track effects of BTFs

– More consistent calculation across members

– Defined in ANSI standard; inputs already captured in statistics reported to NERC

𝐸𝑈𝐹 =𝑈𝑛𝑎𝑣𝑎𝑖𝑙𝑎𝑏𝑙𝑒 𝐺𝑒𝑛𝑒𝑟𝑎𝑡𝑖𝑜𝑛 (𝒅𝒖𝒆 𝒕𝒐 𝑩𝑻𝑭)

𝐴𝑣𝑎𝑖𝑙𝑎𝑏𝑙𝑒 𝐺𝑒𝑛𝑒𝑟𝑎𝑡𝑖𝑜𝑛100

𝐸𝑈𝐹 =𝐻𝑃𝑂+𝐻𝑀𝑂+𝐻𝐹𝑂+𝐻𝐸𝑈𝐷

𝑃𝐻100

Where: HPO = planned outage hoursHMO = maintenance outage hoursHFO = forced outage hoursHEUD = equivalent unit derated hoursPH = period hours (active hours – does not include, e.g., standby or on-call)



Unplanned Capacity Loss Factor (International)

▪ Corollary metric to EUF that is more common outside the U.S.

▪ Reflects unavailable energy due to unplanned equipment failures, etc.

▪ Demonstrates effectiveness of plant programs in maintaining operating availability

𝑈𝐶𝐿𝐹 =𝑈𝐸𝐿

𝑁𝐸100

Where:UEL = total unplanned energy losses (MWh) for the periodNE = nominal energy (MWh) for the period

𝑈𝐸𝐿 = 𝑈𝑃𝐿 ∗ 𝐻𝑅𝑈

Where:UPL = unplanned capacity loss or decrease (MW) due to unplanned eventHRU = hours operated at a reduced power (or shutdown) due to unplanned event



EAL versus EUF

▪ Industry survey responses included EUF; some members providedboth EUF and EAL

▪ Similar general trends

▪ EAL values supported prior assessment as “Very Good BTFR Program”

▪ EUF appears to be a more sensitive availability indicator

▪ BTFR training will focus on revised philosophy outlined in 3002018747

Year Average

EUF

Average

EAL

2015 2.62 1.57

2016 2.99 1.57

2017 3.23 1.64

2018 2.72 1.60

2019 2.69 1.63



The BTFR Program is About

▪ Teamwork

▪ Management support/directive

▪ Consistency

▪ Common terminology

▪ Tools

▪ Damage mechanisms

▪ Root cause

▪ Life assessment



Simple Questions-Accurate Determination of Failure

Mechanism▪ Is circuit water- or steam-touched?▪ Does failure have a thin or thick edge?▪ Is external surface smooth with signs of external wastage?▪ Is wastage localized or over a broad area?▪ Does external appearance look like alligator hide?▪ Are there external or internal cracks or pits?▪ Are cracks circumferential or longitudinal?▪ Is the BTF in a misaligned or sagging tube?▪ Is the failure at or near a weld or a material transition point? ▪ Is failure at or near a bend or attachment?▪ Is the BTF in an area of high heat flux?▪ Are there internal deposits or signs of internal wastage?▪ Is microstructure “rotten” or damaged?▪ Do external deposits contain alkali-iron-trisulfates?▪ Do deposits contain chloride or maricite (NaFePO4)?

Field Personnel Determine 80-90% of Failure Mechanisms during Forced Outages



Fossil Plant Boiler Tube Failures

▪ Seven Steps to Perfection

– Identify failure mechanism

– Determine likely root cause of mechanism

– Confirm failure mechanism and root cause

– Determine extent of damage

– Implement short-term actions → repairs to get unit back in service

– Implement long-term actions → change maintenance, operations, and/or design to prevent future failures

– Determine possible ramifications and similar unit susceptibility



Drive Toward Continuous ImprovementExample of European Utility Experience



Together…Shaping the Future of Electricity


epri's btfr program - ee publishers

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