Presentation Draft ME 2010 Atlanta

8/7/2019 Presentation Draft ME 2010 Atlanta

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Fueling the Minds of Electricity

Marcus Evans 4th

annual Strategic Asset Management for

Power Plants

January 26th 28th

Introduction:

Existing market conditions call for

extra effort involving asset

management of our power plant fleet.

The standard for maintaining power

plant equipment is not the same as it

has been in years past. We do not

have the financial resources due to

budget restraints and the overall

termination of capital projects system

wide. In light of these current market

conditions, we are forced to do more

with less concerning our equipment.

The goal during these times is to use

our expertise and knowledge to

maintain our assets with limited resources. How do we reduce costs while increasing efficiency and

productivity? This workshop will highlight and discuss practical methods that will aid in streamlining

inspection and repair practices.

Changes in maintenance philosophy and the good old days:

If we thought it was tough to get funds

approved to perform maintenance in the

last 10 years, we would be astonished at

what we have to work with now. Utilities

are operating under staunch restrictions.

As a result, the conservative nature of

utility executives is shining through. At the

end of the day, all of us, the asset managers

are left holding the bag.


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Availability performance improvements pertaining to existing units traditionally, prior to current

market conditions:

Utilities have many opportunities to increase electrical output with existing units without increasing fuel

burn. This is achieved by improving efficiency or reducing forced outages through component

replacement and proper maintenance and performance improvements. In some cases, utilities do so asa reaction to unexpected component failures (reactive replacement). In others, utilities replace worn or

aging components that are expected to fail in the future or whose performance is deteriorating

(predictive replacement). In some cases, utilities replace components because more advanced designs

are available and would improve

operating characteristics at the

unit. Such component

replacement can restore a unit's

original design efficiency or, in

some cases, improve efficiency

beyond original design.

Historically, we just simply needed

to justify repairs by data and

component facts. Based off of

those findings, we could justify

funds. Now days its a little more

difficult, utilities are willing to

except greater EFOR and take

more risks when it comes to maintaining the equipment. Environmental impact plays a greater role

than equipment reliability and in some cases safety. Funds are being allocated to pollutant controls, andrenewable fuel source research, and less money is being allocated towards maintaining the actual

equipment that currently energizes our nation.


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Our nations craze for alternative energy sources and fuels has

depleted our efforts to work towards operating our existing

equipment and fuels to their cleanest, fullest potential. Of course,

we should always be looking for ways to improve the process and

operate more efficiently and cleanly. Having said all of this, during

unit operation with most fuels, there are pollutants that we must

battle against as an industry. Through chemistry we have found

ways to control certain emission such as NOx, SOx, Mercury etc,

but yet we still strive as a society to find continuous improvement.

The key here is to practice maintenance procedures that allow us

to operate reliably while controlling these types of pollutants.

Due to maintenance budget cuts etc, we are at risk of sacrificing

reliability due to emissions control equipment usage.


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Availability, reliability, and sustainability in a down economy:

With a reduction in electrical demand throughout the country we find ourselves in a paradigm shift.

Availability has taken a back seat to environmental, safety and economic considerations in running a

power plant. We need to be very cautious here as decisions made in these trying times can have asubstantial impact on our systems sustainability for decades to come. In more robust economic times

we have traditionally suggested availability improvement programs meant to restore the plants'

infrastructure to a level that restores the original reliability of the plants. Implementation of these

recommendations would allow the plants to increase generation output above recent historical output

without increasing gross generating capability.

Maintaining or restoring plants that are over 20 years old to a condition similar to plants that are under

20 years old can result in more reliable facilities that will be available to play an important role in

supporting the increasing strain on our electrical system's reserve margins and electrical demand

growth.

The U.S. electric generating system's reserve margins have declined dramatically over the last 20 years.

This situation has put pressure on the operators of our existing coal-fired fleet to restore, maintain, or

improve the reliability and availability of their facilities to keep pace with the growing demand for

electricity in the face of limited new capacity coming on line. The mandate for higher availability, lower

forced outage rates, and longer time spans between planned outages is more critical today than ever in

our history. But how do we accomplish these goals when we have fewer resources available?

The processes of discovery inspections followed by prioritization and execution of remediation have

proven to be effective historically. Unfortunately many in tough times cut the legs out from under the

discovery inspection portion of the program and expect the same outcome. If we restrict our ability togather information how can we make good decisions on where best to put our limited resources? So we

must maintain a vigorous and robust discovery inspection regime. This effort will provide our decision

makers with a full picture of the condition of the asset. By identifying the most critical problem areas

we can pin point with laser accuracy the monies we do have to spend. We also will have a clear picture

what our risks are going forward.


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Risk management:

Data Driven Planning

The challenges of successfully completing projects within an Operations and Maintenance environment

have increased over the last 10 years. In the Do More with Less" corporate environments,

maintenance staffs have experienced reductions in skilled staffing and budgets. Maintenance projectsare typically driven by unrealistic time constraints and typically delivered late. Both the operations and

maintenance staffs must find the right balance in planning and executing projects. Risk management is

the key to finding the acceptable balance within the project management methodology.

The typical application of the boiler outage project planning process, is to back fit the work flow or logic

into a given timeframe as developed by the boiler inspection scope of work, based on constraining

completion times for the project and with

consideration of resources constraints. The best

practices have the identification of risks (boiler

inspection results) beginning during a project selection

process or during the early planning process. These

risk events, if addressed, are identified as mostly

independent events when analyzed, and may have

several independent responses put in place. Due to the

project inspection team's lack of data or adequate

time, the responses usually consist of putting in place

contingencies of time and money.

While most repairs do not result in a loss of emissions

control, efficiency, performance issues are generally

not addressed when making Cost-based decisions.

While these effects are not directly related, the

secondary effects of disturbances in operation cause a

reduction in overall capacity and increased emissions. Conversely, by closely monitoring thermal

performance at the component level, O&M personnel can improve component reliability by spotting

problems early.

Utilities need to move from a "Cost-based" approach to asset management to a "Value-based"

approach.

The key difference between the two approaches is that the:

Value-based approach involves strategic decision-making that takes the long term affect of repairs into

account when making overhaul repair, replacement, and refurbish decisions.

Cost-based approach relied on available budget (can we afford it?) for maintenance decision-making

that often ignores equipment thermal performance and emissions considerations.


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Choice of Corrective /Preemptive Action:

Repeat tube failures can occur because a temporary rather than permanent

solution is applied to correct and/or prevent the tube failure problem. An

example of a temporary action is the use of sacrificial shields or

metal/plasma sprays to inhibit fire-side corrosion or erosion. A permanentsolution would be based on determining the respective root-cause, such as

a reducing atmosphere in the furnace, excessive flue gas velocity

respectively, and taking appropriate engineering and/or maintenance

preventive action. An example of a temporary action is the use of a window or pad weld to make a tube

leak repair. Best practice would be to immediately replace the damaged tube with a new tube section

(Dutchman), or to replace the window or pad welded section at the next scheduled boiler outage.

Unfortunately, many temporary solutions are not replaced with permanent action, and therefore fail

again within a short time interval.

All scheduled major boiler inspections should include boiler tube wall-thickness measurements in areas

experiencing erosion or corrosion damage, until erosion/corrosion rates are established. In areas

experiencing damage, root cause analysis will be performed and corrective, preventive, and control

actions taken to inhibit forced outages due to these mechanisms.

Problem Definition

Root-cause analysis of every tube failure is a prerequisite mandate for an effective formalized tube

failure prevention program. Before the actual root-cause of a boiler tube failure problem can be

determined, it is essential that the problem be clearly defined in terms of: the failure mechanism

Multidiscipline Approach

Activities associated with boiler tube failures, that is, mechanism

identification, root-cause analysis and verification, and appropriate

corrective and/or preventive action, are complex and usually

require the expertise of several technical/experience disciplines.

Examples could be: mechanism identification may require

knowledge of the metallurgical characteristics of boiler tube steels

at high temperature over time.

Permanent Engineered SolutionsIn many tube failure problems, temporary rather than permanent

engineered solutions are used to solve the problem, with the result that the remedy is a continuing and

costly maintenance burden. A good example might be where tubing is damaged by soot blower erosion

because the blower is located too close to a corner or wall protrusion, yet rather than relocate the soot

blower, the tubing is pad welded or shielded. In most cases, temporary repairs should only be used in

emergencies, with engineering fixes being the permanent solution.


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Operations personnel play a key role in heat rate and emissions

improvement and reliability at facilities where even small gains in

thermal efficiency provide big dividends in terms of improved

financial performance. A major point for plant management is to

recognize the importance of efficiency and availability awareness

among operators, and to make this awareness part of all operators

training. Including this awareness training in operator training is an

important part of any optimization effort. In order to identify

performance problems, the following are offered as inspection

points that can have an immediate impact on controllable heat

losses.

In some cases, emphasis on unit availability (stay running at all costs, regardless of short-term fuel

expenditures, material and labor costs) has been the paradigm for many plants. This is not to imply that

management was wasteful, but simply that the priority was on reliable delivery of power to the

customers, regardless of cost. This approach is easily justifiable because the general public demands andexpects the uninterrupted supply of electrical power. This approach spread across all segments of utility

business.

Training regimes of personnel:

It is essential that all inspection team members have formal

inspection technology training. Insufficient inspection training is

the primary contributing factor to instances of poor performance

of an inspection team. Having a background that well equips an

inspection team member for boiler inspection, in itself, is not

sufficient. This includes engineers, managers, welders, andmechanics; no one involved with the inspection process should

be exempt.

Quality initiatives: Initiatives such as Total Quality Management,

Quality Circles, benchmarking, etc., require basic training about

technology, quality concepts, guidelines and standards for quality, etc.

Safety:Safety training is critical where working with heavy equipment, hazardous chemicals, repetitive

activities, etc., but can also be useful with practical advice for avoiding problems.

y Increased job satisfactionand moraleamongemployeesy Increasedemployee motivationy Increasedefficienciesin processes,resultinginfinancialgainy Increasedcapacity to adoptnewtechnologiesand methodsy Increasedinnovationinstrategiesand productsy Reducedemployeeturnovery Enhancedcompany imagey Riskmanagement


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Certification:

Professional certification can be found in almost every industry in the United States today. Law,

construction, auto repair, nursing, accountancy, information technology training, aerobic instructing,

social work, engineering, software development, and association management just scratch the surface

of the wide range of professions that have voluntary or mandatory certification.

In our industry every employer has a general obligation to perform due diligence in ensuring the

competency of the personnel providing services at our facilities. Boiler Assessment certification provides

employers with evidence that the certificate holder has demonstrated a certain level of job-related

knowledge, skills and abilities. It provides a documented level of assurance that employees are

competent in safe work practices.

Certification provides concrete evidence that

the vendor is staffed with people who know

what they are doing and is competitive in any

comparison of quality of service.

All inspection and service personnel should

be qualified and certified by industry

standards to insure the quality of the

inspection outcome. Even though

certification programs have existed in the

past (ASNT, AWS) none of the previous

certification programs addressed the specific

needs of a power plant. A new organization

has been formed for this express purpose.

The American Association of Boiler Assessors

(AABA) has recently been launched. The

AABA will train, certify, and maintain a

registry of boiler professionals. This is a way

to increase quality and accountability of

Boiler Assessors working in your plants.

Certification demonstrates to governmental oversight, competitors, suppliers, staff and investors that

you use industry-respected best practices.

Certification helps you to demonstrate to shareholders that your business is run effectively. The process

of achieving and maintaining the certification also helps ensure that you are continually improving andrefining your activities. The regular assessment process will improve staff responsibility, commitment

and motivation. Certification can improve overall performance and remove uncertainty as to the quality

and experience of inspection personnel whether they be internal or external.


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Utilization of supplemental Boiler Inspection Team Members:

Intra Company

Personnel from other plants within your system are usually

team leaders or members of their respective plant boiler

inspection teams. This is a popular planned outage concept

as plants within the same system typically remove

equipment from service at different times. A wide range of

experience is enjoyed with such a compilation of talent;

however, their boilers and equipment may be of a different

model and manufacture. Additionally, management policy

may vary from plant to plant potentially confusing the relationship.

The team leader can address these problems by pairing the supplemental personnel with local boiler

inspection team members. Local paring of human resources ensures the policies and interests of the

subject plant are best served. Paring is also important in combining various levels of experience. Paring

experienced inspectors with trainees or lesser experienced inspectors promotes camaraderie and on the

job training, benefiting both the current inspection effort and the collective level of expertise of the

entire company. It is incumbent on the team leader to take advantage of highly trained and

experienced personnel in this manner to ensure optimal performance of the inspection effort.

Contracted Professionals

There are many advantages to contracting experts in the

field of inspection technology. Professional boiler

inspection team members work together during manyoutages each year. A well traveled professional brings a

wealth of expertise and experience to the outage. He is a

valuable source for vital technical information.

Professional consultants should be utilized extensively to

conduct on the job training during the inspection period.

Effective paring will facilitate this goal.

The selected inspection contractor should bring

experience and knowledge of your specific equipment and

the industry in general. They should be knowledgeable in

all aspects of team activity as it pertains to your inspection

program. They should be skilled, efficient, competent and

able to easily adapt to your inspection program. If you use specific software as part of your inspection

program, your contracted inspectors should be knowledgeable in those areas as well. It is important to

research prospective inspection contractors thoroughly to ensure your technical requirements are met.


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Outage management:

Cost Control

The process of cost containment is not just a reduction of total costs. Cost control can only be effective

if we focus the monies available in just the right locations. The shot gun approach or the process of

spending money for the sake of using up the budget will not provide relief from tube leaks. More money

does not necessarily translate into lower availability.

How to maintain our repair budget

The most effective way to maintain your repair

budget is to provide a comprehensive plan

supported by inspections, lab results or other

scientific results. This plan must have a financialcomponent indicating the return on investment in

the repairs. Data driven decision making is the only

consistently effective method to support budgets. In

many cases the data is best supported by good

photography of the problem areas, as well as a

statistical analysis of failures or near failures that

will likely be avoided. Varying lost generation

scenarios at different times of the year usually works well at underpinning your budget requests.

Simple, concise, data supported, and to the point is always more effective than the Chicken Little The

sky is falling technique.

The quality and quantity of your inspections and subsequent data gathered typically has a positive

physiological impact on financial decision makers. A compelling case well presented is likely to develop

more money over time than a more abstract approach.


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Inspections beyond availability

We have been reminded recently that boiler inspections are not completed just to improve availability.

Inspections have from the beginning of boiler operation, been a tool to prevent loss of life and injury to

the public. We have been historically successful in application of the ASME rules for construction and

repair to a point where the personal injury objective has been over shadowed by the desire to improveunit availability and performance. Our national fleet average age is now approaching a critical point

where years of operation have caught up with us. We can expect problems to arise that have not

traditionally been a problem. Things such as corrosion fatigue, under deposit corrosion, and cold side

corrosion to name a few, will become more prominent going forward. In many cases these problems are

especially dangerous since they will likely fail to the cold side or outside the boiler proper. These are

significantly more dangerous to personnel

than historic tube failures.

The methodology for outage repair planning

has been to consider the problems that have

occurred in the past, and proactively repair

and replace based on that knowledge. This

method has served us well in that tube leak

failure rates have been maintained below 4%

nationally. This method is likely to fall short

in the future since the expected problems

will not have history to support our activities.

In some cases, we will have first time failures.

These failures can be devastating when a loss

of life or injury occurs in the process.

Since we have the scientific and accumulated knowledge of these potential leaks, they are preventable.

This is where the problem occurs. It is indefensible to have a personal injury when the means and

knowhow were available to prevent the loss. We will be held accountable if we do not act.

Unfortunately this approaching tube leak problem occurs when budgets are under financial pressure

due to economic restraints. We have to factor in the ethical and financial impact of a loss of life and/or

injury due to our failure to act to prevent the failure.

When budgets are tight, the boiler inspection effort has traditionally been reduced or eliminated for the

outage execution. This thinking has to be reversed. As the boiler equipment ages, the likelihood of

failure increases therefore the inspection and repair budget need to expand, not contract.


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Boiler/Steam Generator:

The primary cause of unavailability of our fossil -fired plants is the reliability of the boiler/steam

generator. Severe duty on both the fire side and the water/steam side of the various heat transfer

surfaces in the boiler/steam generator cause frequent unplanned outages and lengthening of planned

outage failures to these critical components of the power plant. Replacement of these components willsignificantly reduce outages and increase the facility's availability and total generation output capability

and emissions.

In the past the three primary areas of the boiler system were compartmentalized. These areas were;

Pulverizer / Burners

Boiler pressure parts

Emissions control equipment

It is known that by combining all

three into one model. Treating thesystem as a whole not individually

we can achieve far more

constructive results than by three

separate non overlapping

approaches. This holistic approach

creates many opportunities that

never were identified before

application of this methodology.

This synergistic approach is not new

as Aristotle concluded The whole ismore than the sum of its parts

thousands of years ago. Our

industry is just beginning to embrace

this concept as experts in these

three fields are interacting to

improve the overall outcome of

availability, sustainability,

performance and emissions.

Plant efficiency, availability, emissions, and safety are determined by process inputs and outputs fromthe coal yard to the stack. The economic and operating benefits of managing and improving the

complete process are substantial.

The alliance seen in the graphic was formed to be a foundation of area specific experts able to facilitate

the coordination of functioning initiatives within power plant groups. This joint effort results in

improved boiler reliability, plant efficiency, and overall environmental impact.


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Combustion, boiler pressure parts, and emissions:

When we take a holistic approach to the plant maintenance and operational challenges we must

consider some of the factors listed and how they interact with the entire process.

Coal

Bituminous coals from Eastern mines, sub-bituminous and lignite coals from Western mines, and

lignites from Texas mines are substantially different from each other in the combustion process. Coal

blending is now used for operational and financial benefits. This results in a wide range of boiler and

precipitator operating conditions.

Precipitating fly ash from difficult coals can be improved with conditioning systems. However, the

furnace and its associated equipment can still cause problems in the precipitator, particularly coal mills,

burners, and air pre-heaters.

Coal Mills

The setting of the coal mills and classifiers defines the coal particle size which in turn impacts the fly ash

particle size. Larger coal particles are more difficult to combust, but larger fly ash particles are easier to

collect in the precipitator.

Furnace

Base-load operation of the boiler is usually better for precipitator operation than swing-load operation

due to more stable operating conditions. Boiler operation at low loads may be as problematic for the

precipitator as operating the boiler at its maximum load level, due to fallout of fly ash in the ductwork,

low gas temperatures, and deterioration of the quality of the gas velocity distribution.

If low load operation cannot be avoided, the installation of additional gas flow control devices in the

inlet and outlet of the precipitator may prove beneficial.

Coal Burner

The operation of coal burners, together with the setting of the coal mills and their classifiers, affects the

percentage of unburned carbon (LOI or UBC) in the fly ash. The use of Lo-NOx burners increases this

percentage, and causes re-entrainment and increased sparking in the precipitator. Further, the UBC

tends to absorb SO3, which in turn increases the fly ash resistivity. Over-fire air optimization or coal-

reburn systems may reduce UBC in the fly ash.

Air Pre-heater

Regenerative air pre-heaters cause temperature and SO3 stratification in the downstream gas flow. This

problem is more severe in closely coupled systems, where the precipitator is located close to the air pre-

heater. Depending upon site-specific conditions, flow mixing devices may be installed in the ductwork to

the precipitator, or flue gas conditioning systems may be used to equalize the gas flow characteristics.


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Fly Ash and Flue Gas Conditioning

Flue gas and fly ash characteristics at the inlet define precipitator operation. The combination of flue gas

analysis, flue gas temperature, and fly ash chemistry provides the base for fly ash resistivity. Typically, fly

ash resistivity involves both surface and volume resistivity. As gas temperature increases, surface

conductivity decreases and volume resistivity increases.

In lower gas temperature ranges, surface conductivity predominates. The current passing through the

precipitated fly ash layer is conducted in a film of weak sulfuric acid on the surface of the particles.

Formation of the acid film (from SO3 and H2O) is influenced by the surface chemistry of the fly ash

particles.

In higher gas temperature ranges, volume conductivity predominates. Current conduction through the

bodies (volume) of the precipitated fly ash particles is governed by the total chemistry of the particles.

Fly ash resistivity can be modified (generally with the intent to reduce it) by injecting one or more of the

following upstream of the precipitator:

Sulfur trioxide (SO3) Ammonia (NH3) Water

Sulfur Trioxide and Ammonia Conditioning Systems

In most cases, a sulfur trioxide conditioning system is sufficient to reduce fly ash resistivity to an

acceptable level. The source of sulfur trioxide can be liquid sulfur dioxide, molten elemental sulfur, or

granulated sulfur. It is also possible to convert native flue gas SO2 to SO3.

In some instances, ammonia alone has been proven a suitable conditioning agent. It forms an ammonia-

based particulate to increase the space charge. The source of ammonia may be liquid anhydrous or

aqueous ammonia, or solid urea.

Finally, sulfur trioxide and ammonia may be used in combination. This solution has been successful

because it can lower fly ash resistivity and also form ammonia bisulfate. The latter increases the

adhesion of particles, and thus reduces re-entrainment losses.

Water Injection

The injection of water upstream of the precipitator lowers the gas temperature and adds moisture to

the flue gas. Both are beneficial in cold-side precipitator applications. However, care must be taken that

all of the water is evaporated and that the walls in the ductwork or gas distribution devices do not get

wet.


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Streamline the inspection and repair process:

This work shop has discussed the importance of certain procedures and practices during these

challenging economic times; however, organization and execution of these procedures and practices are

required to make a difference. It is understood that you need trained and qualified personnel toperform your work. Once you develop your

plan of maintaining your assets with the

resources you have available, the next step

is to organize the practices and then you

need to execute. If it is part of your outage

plan to have inspection crews only record

priority 1 items (any item identified that

will bring the unit off-line prior to the next

scheduled shut down), then these P1 items

will require supervision to ensure the

repairs are made. Making a successful

repair and executing above and beyond the

initial process of finding the damage is

imperative. The follow through and

execution of this process is vital. If the

preparations and plans for an inspection

team include particular items of equipment,

the process of getting all of this equipment

on site in time for inspections would be to

execute the process. Every part of the

inspection and repair process started with a

plan, and should end with execution.

The organize and execute method is important when efforts are being made to streamline the

process. If we are limited on resources, we need to optimize the process. Follow these steps:

1) Plan2) Organize3) Execute4) Follow up

There is synergy between the execute and follow up stages. For whatever part of the plan that did not

get executed properly, there will be a follow up plan to satisfy the agenda. If a particular damage

mechanism was identified, however the repair was not performed and executed , the follow up will

begin the next step. The follow up may include future plans, or maybe an adjustment that still supports

the original organized plan.


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Presentation Draft ME 2010 Atlanta

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