a novel approach to storing and returning feedwater heater shells to service

7/21/2019 A Novel Approach to Storing and Returning Feedwater Heater Shells to Service

1/719PowerPlant Chemistry 2008, 10(1)

PPChem

INTRODUCTION [1]

For more than forty years, copper migration and deposi-

tion have been major problems in fossil-fuel power plants.

Coming from a variety of locations, including the steam

side of copper-alloy feedwater heaters, copper particles

tend to concentrate during startups due to thermal

stresses on the equipment. As a result of copper migra-

tion, various points throughout utility stations become tar-gets for deposition. Such points include the boiler water

walls, boiler steam drums, primary superheaters, and high-

pressure (HP) turbines. When copper and/or other oxides

deposit on heat exchange surfaces downstream of feed-

water heaters, efficiency is reduced and loss of generation

capacity becomes a problem.

Of particular concern is the oxide transport from the feed-

water heaters during unit startups. While most utility sta-

tions with copper-alloy heat exchangers maintain a reduc-

ing chemistry during normal operations, some allow oxi-

dizing conditions to exist during outages. These oxidizing

environments, when coupled with changes in flows, tem-

peratures, and startup chemistry, tend to lead to exfolia-

tion and transport of very high quantities of metallic oxides

including copper. Unfortunately, condensate polishing

does not remove all of this material. While the particulate

removal of iron and other oxides does occur during the

cleanup phase, condensate polishing does not always sig-

nificantly reduce copper transport [2]. As a result, copper

tends to stay in the system longer and deposit on the vari-

ous plant components during the early phases of the

startup.

STATEMENT OF PROBLEM

Western Farmers Electric Cooperative (WFEC), with head-

quarters in Anadarko, Oklahoma, is an electric generation

and transmission cooperative providing electric power to

much of rural Oklahoma. WFEC's Hugo Unit 1 (Fort

Towson, Oklahoma), the primary generation resource, was

commissioned in April 1982 at 442 MW and upgraded in

2000 to 475 MW. A Babcock & Wilcox Carolina-type boilerproduces the main source of steam, at 1 510 t h

1

(3.33 million lb h1). Steam drum pressure is rated at

20.51 MPa (2 975 psi) and the superheater supplies

541 C (1 005 F) main steam to the HP turbine at

18.2 MPa (2 640 psi). The reheater supplies 541 C

(1 005 F) reheated steam to the intermediate-pressure (IP)

turbine at 4.02 MPa (583 psi). The primary fuel source for

the boiler is Powder River Basin coal.

Hugo Unit 1 has four low-pressure (LP) feedwater heaters

and two high-pressure (HP) feedwater heaters. The deaer-

ator (or #5 feedwater heater) is positioned between the LP

and HP heaters. The four LP heaters contain admiralty

SB-395 tube material and the two HP heaters contain

70/30 copper-nickel tubes. All heaters have carbon steel

shells. LP heaters #1 and #2 are mounted into the side of

the main condenser, which also contains copper-nickel

tubes. The LP heater shells receive extraction steam from

various points of the LP turbine. Beginning with the shell

side of the #4 heater, the condensed steam from the LP

heater shells cascades back through the drain system to a

collection tank, from which it is re-injected into the feed-

water system between LP heaters #1 and #2. HP heater #6

shell receives extraction steam from the IP turbine and HP

heater #7 receives extraction steam from the cold reheat

A Novel Approach to Storing and Returning Feedwater Heater Shells to Service

2008 by PowerPlantChemistry GmbH. All rights reserved.

A Novel Approach to Storing and Returning Feedwater

Heater Shells to Service

Tom Pike and Douglas Dewitt-Dick

ABSTRACT

Feedwater heater shells are frequently left unprotected during unit shutdowns and outages. Even though means are

generally available during outages to protect these critical areas, many plants either fail to protect the heater shells or,

in some cases, opt to leave the shells exposed to damaging environments. Failure to protect heater shells, even during

short outages, can exacerbate problems with metal oxide transport when returning the heaters to service particularly

if the heaters contain copper-bearing tubes. This paper investigates a novel approach used by one utility to circumvent

problems with oxide transport due to inadequate heater shell storage. It discusses structural modifications incorpo-

rated by the plant to improve the storage process. It also details the proper chemistry and testing procedures neces-

sary for shell protection under various conditions. Equally important, this paper outlines critical controls for minimizingcopper oxide transport during subsequent unit startup.


2/720 PowerPlant Chemistry 2008, 10(1)

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line coming from the HP turbine. As with the LP system,

the condensed steam from the HP heater #7 shell cas-

cades back to the HP heater #6 shell where both conden-

sates are re-injected into the feedwater system at the

deaerator.

Due to years of service and the number of plugged tubes,LP heater #2 was retrofitted with ASTM SB 395 admiralty

(UNS 44300) tubes during the 2006 spring outage. In addi-

tion, HP heater #7 is scheduled for re-tubing in 2009 and

HP heater #6 is scheduled in 2011. It has not been deter-

mined whether the re-tubing of the HP heaters will involve

70/30 copper-nickel material or stainless steel.

With copper-alloy tubes in both the condensate and feed-

water systems, copper transport to the boiler is a certainty.

The question then becomes how to minimize the transport

of copper and other oxides to the boiler. Oxide transport

studies conducted by the Hugo Plant during both normaloperations and unit startups indicated that the vast major-

ity of copper and other oxides were transported to the

boiler during the first few hours of unit startups particu-

larly following outages in which the feedwater heater shells

were not stored. In the fall of 2003, the problem facing the

Hugo Plant concerning copper transport was two-fold:

1. how to minimize copper oxide transport to the boiler

during these critical periods; and,

2. how to store the HP/LP feedwater heater shells to mini-

mize copper oxidation in its incipient stages.

REDUCING COPPER TRANSPORT

During the 1990s, the Hugo Plant conducted a series of

copper-transport studies to determine how and when cop-

per was migrating from the feedwater system to the boiler.

Key to these studies [3] was the corrosion products sam-

pler1. The corrosion products sampler is an on-line sam-

pler that collects dual-stream water samples over a period

of time by filtering the water through a series of three filter

pads. The first filter pad, a 0.45 m membrane filter, col-

lects particulate or suspended material in the water

stream. The second pad, a cation filter, collects any posi-

tively charged material including metal ions in the sam-

ple stream; and the third and final pad, an anion filter, col-

lects any negatively charged materials. All three filter pads

are secured within a sealed compartment to prevent con-

tamination and to secure the integrity of the samples.

During the sampling process, the volumes of water being

filtered through the dual-stream samples are measured

and totalized. This method allows the corrosion products

sampler to collect two samples simultaneously based on

time or volumes of water filtered. After the samples are col-

lected and analyzed, the mass flows through the sampler

can be compared to the mass flows through the system.

This mass flow comparison, along with the metal loading

(particulate plus dissolved species), can be used to deter-

mine how much metal oxide was transported through a

specific leg of the system during the trial period.

Using this technology, the Hugo Plant determined that

much of the particulate and dissolved copper deposited inthe boiler was transported from the feedwater system dur-

ing the early stages of unit startups. With the sampler, it

was further determined that the vast majority of the copper

was released from the shell side of the HP/LP feedwater

heaters and transported directly to the boiler. As was

expected, the nature and length of unit outages had a sig-

nificant impact on the amount of copper ultimately trans-

ported. Typically, longer outages generated more copper

oxide for release from the heater shells than did the shorter

turnaround outages. Likewise, startups following outages

in which the HP/LP feedwater shells could not be ade-

quately stored tended to release more copper.

During a boiler maintenance and cleaning outage in the fall

of 2003, the Hugo Plant developed a procedure to reduce

copper transport to the boiler during the subsequent

startup. The implementation of this procedure was

straightforward, taking plant design into consideration.

The Hugo Plant, like most utility stations, uses extraction

steam from the turbines to heat the feedwater as it moves

through the heaters on its way to the boiler. Generally, the

extraction steams are not placed into service until the unit

has been on-line for awhile and all systems are stable. For

the Hugo Plant, this equates to 40 MW for placing the

deaerator into service and 60 MW for the HP/LP feedwater

heaters. Because the shells of all the feedwater heaters are

supplied with steam from the turbines supposedly

"clean" sources the design engineers apparently did not

think it necessary for the HP drains and LP drips to be fil-

tered through the condensate polisher before going to the

boiler. Under normal operations, these drains and drips do

not need additional polishing; under startup conditions,

however, drains and drips have tremendous copper load-

ing and should be diverted through the condensate pol-

isher until the copper loading can be reduced to accept-

able levels.

The corrosion products sampler data indicated the release

of high levels of both particulate and dissolved copper

from the HP drains and LP drips during startups. In addi-

tion, the HP drains contained higher than acceptable levels

of nickel. Unfortunately, during startups, as with normal

operation, all HP drains and LP drips were re-injected into

the feedwater system downstream of the condensate pol-

isher. In other words, these excessive amounts of copper

and nickel oxides were bypassing the polisher and going

straight to the boiler. This all changed during the fall 2003

outage.

In November 2003, the Hugo Plant was involved in a boiler

maintenance and cleaning outage. The plant would be

returned to service with a clean boiler, so it was decided to


1SENTRY Corrosion Products Sampler, Model CPS-20. .



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take the necessary steps to prevent the boiler from

becoming immediately fouled with copper and other

oxides when returned to service. The sampler data estab-

lished the problem as being the shell sides of the HP/LP

heaters; the question then became what to do with the

heavily contaminated drains and drips from the heater

shells. Dumping these to the floor presented numerouslogistical problems so it was decided to divert the HP

drains and LP drips back to the condenser via the emer-

gency dumps. The objective of this process was to force

the copper-contaminated condensate from the shells of

the HP/LP heaters back through the condensate polisher

prior to going to the boiler. In addition to cleaning the con-

densate early in the process, this procedure allowed

greater control over copper migration to the boiler.

Because many utility stations have some means of moni-

toring water quality from the HP drains and LP drips, the

operators using this procedure determine when the heater

shells are clean enough to place in normal operation. Thismethod allows plants to control copper limits between the

condensate polisher and the feedwater outlet by leaving

the emergency dumps to the condenser in the open posi-

tion until the copper concentration has dropped to an

acceptable level. For the Hugo Plant, this time varies

depending on the storage status of the feedwater heater

shells. When the heater shells are stored with wet chem-

istry, the copper limits are met shortly after introducing

extraction steam into the shells. On the other hand, when

the shells are stored as-is, the copper limits generally are

not met for 12 h or more after introducing extraction

steam.

STORING FEEDWATER HEATER SHELLS

Some utilities maintain the philosophy that storing the

HP/LP feedwater heater shells during outages is not nec-

essary for two reasons: These systems are supplied with

"clean" steam from the turbines and should not present a

problem; and, the overall mass flow from the feedwater

heater shells is relatively small compared to the total mass

flow going to the boiler, therefore, impact on the boiler

water quality is minimal. Only part of this scenario is accu-

rate the extraction steam diverted from the turbines to

the heater shells is, in fact, clean that is, unless contami-

nated with oxides that form in heater shells during out-

ages. Proper storage of feedwater heater shells is para-

mount to maintaining the overall health of any utility sta-

tion. The question should not be whether or not to store

the shells; rather, the question should be which storage

method best meets the needs of the station, based on the

length and nature of the outage.

Storing the feedwater heater shells can be accomplished

in a number of ways. One method, incorporating nitrogen

blankets under slight positive pressure, has been success-fully used throughout the industry for a number of years.

The Hugo Plant, however, had concerns about personnel

safety when abandoning the nitrogen blanket method

soon after going commercial. Valve integrity between the

shell-side nitrogen blankets and main condenser were an

issue, especially because employees and contractors

were frequently inside the condenser either performing

maintenance or inspections. For this reason, the heater

shells were generally stored "as-is" when coming off-line

for an outage. The as-is condition meant that the belly-drains on the bottom of the heater shells were left open to

drain condensate that collected in the heater as it cooled

down to ambient conditions. Many utilities, for either

safety or convenience, continue to leave the heater shells

in the as-is condition when coming off-line.

The problem with the as-is method of shell storage

becomes apparent once it is understood that if water can

drain out of the shell, then air can get into the shell. This air

ingress into the heater shell exposes heater tube surfaces

to the air; in many cases, this exposure continues through-

out the outage. This oxidation of the shell-side coppertubes may, in fact, help explain why the industry is plagued

with extremely high levels of dissolved and particulate

copper during unit startups [2]. At the Hugo Plant, for

example, when heater shells were stored as-is, copper

oxides were generated very rapidly during the first 36 h of

an outage. It was not unusual to generate up to one pound

of copper metal per hour from the heater shells during

these critical hours. This rapid rate of growth, however,

began to flatten out somewhat when outages lasted more

than two or three days. It appeared as though the oxide

deposits forming on the shell side of tubes became satu-

rated and grew at a slower rate after the first few days. As

expected, the real issue with the shell-side copper oxide

did not become apparent until the station was returned to

service.

During subsequent startups, it was believed this newly

formed oxide did not tightly adhere to the tubes and would

be the first material flushed from the heater shells. Whether

the oxide was removed by thermal shock or by steam

washing did not matter. The obvious problem was the

unacceptably high amount of copper oxide being flushed

from the shells and into the feedwater system. Because

the Hugo Plant had the shells cascading back to the feed-

water system and bypassing the condensate polisher, this

copper oxide went directly to the boiler. This process was

not a one-time occurrence; it occurred with every cold

startup. Even following quick turnaround outages, during

which the heater shells were opened to atmosphere,

oxides were transported to the boiler.

This theory was somewhat supported during the fall 2006

outage. During this outage, maintenance crews opened

the HP #6 heater for inspection and repairs. During the

inspection, it was determined via eddy-current testing that

25 % to 30 % of the copper tubes in the vicinity of the

extraction steam inlet were either below minimum wallthickness or had already failed. Other scenarios are being

considered but the general consensus at the Hugo Plant is

that the tube walls became thinner as repeated layers of




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oxides were formed during outages and subsequently

removed during startups as steam was re-introduced into

the heater shells.

To help correct for this excessive buildup of oxides, a stor-

age procedure was implemented for the feedwater heaters

incorporating minor changes in the plant structure.Because the condensate head tank served as the water

source, fill-lines were attached to existing condensate lines

leading from the head tank to allow the heater shells to be

filled at any time during an outage, regardless of the status

of the condensate and feedwater systems. These new fill-

lines were capable of supplying enough chemically treated

condensate, under 118147 kPa (40 to 50 feet) of head

pressure, to fill two or more heater shells simultaneously.

Before removing the Hugo Plant from service, the length of

the outage and the nature (or expected maintenance) is

generally known. Based on this information, the chemicaldoses are determined beforehand and are ready to add to

the head tank as soon as the equipment is available for

storage. When the condensate head tank and the heater

shells are available, a reducing agent and an amine are

added to the head tank. Initially, the water level in the head

tank is near empty. The purpose of starting with a low level

is threefold: This allows for thorough mixing of chemicals

while the tank is filling; it allows operators to monitor water

quality; and, finally, it allows for periodic testing and chem-

ical adjustments. Thus far, the Hugo Plant has investigated

two reducing agents for equipment storage: an organically

catalyzed hydrazine and catalyzed methyl ethyl ketoxime

(MEKO). These reducing agents have been used at the

Hugo Plant since the early 1990s with excellent results.

Both agents are catalyzed to protect copper and iron com-

ponents at ambient temperatures [4]. Depending on the

length of outage, the concentration of reducing agent is

targeted between 3.570 mg L1

for heater shell storage

(70 mg L1

reducing agent is only used during periods of

extended outages). Next, an amine is added to adjust the

pH upward and to help drive the oxidation reduction

potential (ORP) into the negative or reducing range.

This reducing environment helps protect both copper and

iron surfaces for the duration of the outage. Currently, two

propriety amine blends are under investigation. The HugoPlant is investigating amine blends incorporating cyclo-

hexylamine with morpholine (amine #1) and cyclohexyl-

amine with monoethanolamine (amine #2). The pH of the

condensate head tank is brought into target range (9.5 to

10.0) as fresh demineralized water is pumped into the head

tank to the required level. During this filling process, the pH

of the water is monitored and adjusted as needed. When

the head tank is full, the water contains proper concentra-

tions of both the reducing agent and amine. This solution is

capable of protecting both copper and iron components

inside the heater shells for the duration of the outage. (To

help maintain correct levels of the reducing agents and

amines, curves specific to the Hugo Plant were con-

structed; see Figures 16).


Figure 1:

Amine #1 pH and ORP in the presence of 20 mg L1

catalyzed

methyl ethyl ketoxime.

Figure 2:


catalyzed

methyl ethyl ketoxime.

Figure 3:

Amine #1 pH and ORP in the presence of 3.5 mg L1

catalyzed

hydrazine.



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At this point, the water and chemical mixture is ready to be

added to the heater shells. The belly-drains on the heaters

are in the open position, as are the top vents. The water

and chemical mixture is drained from the head tank

through the fill-lines and into the shells. At the Hugo Plant,

one head tank volume can fill all six heater shells with a

small reserve remaining. Generally, this reserve is usedwithin a week to correct for leaks that invariably occur.

After the shells are filled, as evident by sight glass level

indicators or water coming from the top vents, the vents

can then be closed, along with the belly-drains and any

other open lines. The heater shells are now under wet stor-

age.

As with any good storage or lay-up program, periodic

monitoring for program integrity should be conducted. The

concentrations of reducing agent and amine should be

checked and adjusted as needed. Other parameters can

be tested to give insight into the efficacy of the storageprocess. The quality of the sample, however, should

always be taken into consideration; since a static system

is being measured, a single analysis may not be represen-

tative of the bulk water chemistry inside the shells. Trends

or changes over time are typically better indicators of shell

chemistry than are single tests.

In preparation for the subsequent startup, the chemicals

from the shells can be drained back to the condenser and

cleaned via pre-startup recirculation through the conden-

sate polisher; or, the chemicals can be disposed of in

accordance with state and federal guidelines. As the unit

comes on-line and extraction steam from the turbines is

re-introduced to the heater shells, any residual chemicals

are quickly removed by flushing to the condenser.

DISCUSSION

In an effort to protect steam system components, deposit

formation and chemistry are being researched. This new

information is leading to a greater understanding of both

boiler water chemistry and feedwater quality. Research

has shown, for example, that the most oxidized copper

state, cupric (Cu2+), is also the most volatile. The next oxi-

dized state, cuprous (Cu+), is the next most volatile copper

species. Copper metal (Cu) is the least volatile of the cop-

per species. These data become more important when

copper oxide deposits, such as those formed in feedwater

heaters, are exposed to the increasingly oxidizing environ-

ments during unit outages and startups.

Boilers and other steam components are also vulnerable to

oxidation during unit outages and startups. The startup of

a utility station tends to allow air inleakage and exposes

protective oxide layers to unacceptably high levels of oxi-

dation; this, in turn, disrupts the stable chemistry of routineoperations. Cuprous oxide (Cu2O), for example, is the pro-

tective coating of many passivated feedwater systems.

This coating, formed in reducing environments, can be


Figure 4:

Amine #2 pH and ORP in the presence of 3.5 mg L1

catalyzed

hydrazine.

Figure 5:


catalyzed

hydrazine.

Figure 6:


catalyzed

hydrazine.



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easily destroyed during relatively short periods of air

inleakage into copper-bearing vessels [5]. Such air inleak-

age makes the control of ORP difficult, particularly during

startup, and can negatively impact copper throughout the

condensate/feedwater systems. When the feedwater sys-

tem is exposed to an oxidizing environment, the ORP is

positive and the cuprous oxide is converted to cupricoxide (CuO), thus increasing copper transport.

Unfortunately, this transition can occur within hours of the

initiation of an oxidizing environment.

The shell sides of the HP/LP feedwater heaters can also

add substantial amounts of copper and other oxides to the

system through the cascading drains. During periods of

exposure to highly oxidizing environments, much of the

protective copper oxide coating can be dissolved and

transported further downstream. Steam generator water

wall tubes are typically exposed to greater levels of copper

following a unit startup. Often, this transported copperbecomes interspersed with the protective magnetite layer

(Fe3O4) found in the boiler/steam system. This interspers-

ing of copper can cause additional problems inside the

boiler such as under-deposit corrosion.

Most of the feedwater copper is transported to the boiler

during these highly oxidizing startups. During these peri-

ods, copper transport is mostly in particulate form and can

range from 7595 % of the total copper transport [2].

Some of this copper, however, is deposited in the pre-

boiler section. In the HP heaters, for example, copper can

be deposited electrochemically inside the tubes. In these

cases, a type of copper "foil" or "snakeskin" is formed

inside the tubes of the HP heaters. This snakeskin should

be removed as soon as possible from the heaters; other-

wise, thermal and flow stresses can cause its release and

ultimate transport into the boiler. This is not the only

mechanism copper has for reaching the boiler from the HP

heaters. Denickelfication of the HP heaters, for example,

can result in copper transport during startups being from

6070 times greater than during normal operations [6].

CONCLUSION

Equipment storage during outages is critical to the overall

health of any utility station. Damage from corrosion to the

various systems frequently occurs during outages and is

well established in the literature. In many cases, inade-

quately planned or implemented lay-up programs account

for more corrosion damage to equipment than occurs

under normal operating conditions [7].

When a unit is brought off-line for an outage, the equip-

ment should be stored as soon as practical this includes

the feedwater heater shells. At the Hugo Plant, as with

many utility stations, oxidation of the shell-side coppertubes begins soon after exposure to the atmosphere via

drains and vents and can result in startup copper concen-

trations as high as 1.02.5 mg L1

in improperly stored

vessels. Even relatively short exposure periods can

account for several pounds of copper oxide being formed

and transported to the boiler during the subsequent

startup. For this reason, shell storage early in the outage is

necessary for maintaining the health of any station.

Once a storage program has been implemented, routinemonitoring of the various components is crucial to the suc-

cess of the program. With a wet storage, for example,

monitoring of the water/chemical levels in the various

shells is necessary to ascertain that no leaks exist. It

should not be assumed that leaks are always visible; in

many cases, valves leak internally and drain the protective

water away from the shells. Also, amine and reducing

agent concentrations should be checked to make certain

these parameters remain within range to protect copper

and iron components. Adjustments to the program can be

made as needed.

Finally, it is a good practice to flush heater shells prior to

returning them to service. During unit startups, the extrac-

tion steam of even properly stored heater shells should be

diverted through the emergency dumps back to the con-

denser to remove any residual oxides and chemicals. This

initial flushing of the feedwater heater shells also allows

copper concentrations time to drop to acceptable levels

prior to placing the heaters in normal operation. The time

required for this flushing process depends primarily on

how well the heater shells were stored. For properly stored

shells, this flushing may be completed when the heaters

are ready to place into service. For shells stored as-is, this

flushing process may take up to 12 h or longer; but these

few hours of reduced heater efficiency are well worth the

overall benefit to the plant of not having copper oxide

needlessly transported to the boiler.

ACKNOWLEDGMENT

The authors wish to thank David Sonntag, Operations

Superintendent of the Hugo Plant, for his valued insight

and comments during the writing of this paper.

REFERENCES

[1] Pike, T., Lange, E., Proc., International Water Con-

ference, 2001 (Pittsburgh, PA, U.S.A.). Engineers'

Society of Western Pennsylvania, Pittsburgh, PA,

U.S.A., 62, Paper #01-27.

[2] Howell, A., Proc., International Water Conference,

1998 (Pittsburgh, PA). Engineers' Society of Western

Pennsylvania, Pittsburgh, PA, U.S.A., 59, Paper #98-

22.

[3] Pike, T., Proc., International Water Conference, 1999(Pittsburgh, PA, U.S.A.). Engineers' Society of

Western Pennsylvania, Pittsburgh, PA, U.S.A., 60,

Paper # 99-52.




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[4] Rondum, K. D., Fuller, E. J., Dewitt-Dick, D.,

Bargender, A. M., Proc., International Water Con-



U.S.A., 50, 124.

[5] Guidelines for Copper in Fossil Plants, 2000. Electric

Power Research Institute, Palo Alto, CA, U.S.A.,

1000457.

[6] Lawrence, G. S., Proc., International Water Con-



U.S.A., 56, 261.

[7] Pike, T., Proc., International Water Conference, 1987

(Pittsburgh, PA, U.S.A.). Engineers' Society of

Western Pennsylvania, Pittsburgh, PA, U.S.A., 48,

200.

This paper was presented as part of the 68th Annual

International Water Conference, which took place in

Orlando, FL (U.S.A.), October 2125, 2007.

THE AUTHORS

Tom Pike (B.S., Baylor University, Waco, TX, M.S., Califor-

nia State University, CA, both in the U.S.A.) has been a

plant chemist at the Western Farmers Electric Coopera-

tive, Fort Towson, OK, U.S.A., for 27 years. His main areas

of research include corrosion control of condensers, feed-

water heaters, and turbines during idle periods, reduction

of metal oxide transport (especially during unit startups),

reliability improvement of high-pressure boilers, improve-

ment of pretreatment water systems in fossil plants, and

removal of copper from high-pressure turbines while on-

line. Tom Pike is a member of NACE, ASTM, and ASME.

He has over 15 publications, has been a speaker at manyconferences and workshops, and is a co-holder of two

patents.

Douglas Dewitt-Dick (B.S. Chemical Engineering, Univer-

sity of Michigan, Ann Arbor, Michigan, U.S.A.) joined

Ashland Water Technologies (formerly Drew Chemical) in

1983 after working for Basin Electric Power Cooperative in

Beulah, ND, U.S.A. He is the principal consultant in the

Global Technology Group and has responsibility for devel-

oping and promoting technology in the field of industrial

and utility water treatment. He is a member of NACE

International and the ASME Research and TechnologyCommittee on Water and Steam in Thermal Systems, and

serves on the Advisory Council of the International Water

Conference.

CONTACT

Tom Pike

Western Farmers Electric Cooperative

P.O. Box 219

Fort Towson, OK 74735U.S.A.

E-mail: [email protected]


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a novel approach to storing and returning feedwater heater shells to service

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