Continuum* AEC Programs - Answers to Questions Most Frequently Asked Concerning Continuum AEC Programs
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Profile
Continuum* AEC Programs
Answers to Questions Most Frequently Asked Concerning
Continuum AEC Programs
What are Continuum and Continuum
What is an Alkyl Epoxy Carboxylate?
AEC programs?
Alkyl Epoxy Carboxylate, or AEC, is a generic name
Continuum* programs are treatments for alkaline for the three organic reactants used to manufac-
cooling water. Water & Process Technologies from ture this GE-synthesized scale and corrosion in-
GE Power & Water, the leader in cooling water
hibitor. The AEC molecule contains only carbon,
treatment, provides Continuum programs which are
hydrogen, and oxygen. AEC contains no residual
environmentally preferred corrosion/deposition con- epoxides.
trol for cooling water systems operating above
pH 7.8.
What Can a Continuum AEC Program
Continuum AEC programs are the newest develop- Do for Me?
ment in these alkaline cooling water treatments.
Continuum AEC programs combine a novel calcium Optimize Production Rates
carbonate scale/corrosion inhibitor and a superior
phosphorus-based steel corrosion inhibitor pack- Continuum AEC programs help keep heat ex-
age. Compared to conventional alkaline treatments, changer surfaces clean by preventing deposition
Continuum AEC programs provide the highest level of calcium carbonate scale — even in high calcium
of safety and environmental acceptability. waters. Clean surfaces are needed to achieve
peak heat transfer rates and are essential for pro-
What is AEC? duction units to meet output goals.
Alkyl Epoxy Carboxylate, or AEC, is the first major AEC is the first non-phosphorus calcium carbon-
breakthrough in calcium carbonate deposit control ate inhibitor which is safe to apply in high calcium
in more than 25 years. AEC is a patented, nonphos- waters. Phosphonate inhibitors are susceptible to
phorus, organic scale inhibitor that is exclusive to precipitation in high calcium waters. Calcium
GE. AEC functions as a threshold inhibitor and is the phosphonate precipitates settle on heat ex-
only non-phosphorus deposit control agent that changer surfaces resulting in reduced heat trans-
provides scale control superior to phosphonate fer and lower production rates.
technology.
Reduce Operating Costs
In addition to its deposit control properties, AEC is
Because of its high calcium tolerance, AEC allows
an effective steel corrosion inhibitor when used with
towers to operate at higher cycles of concentra-
low levels of inorganic salts (phosphate, zinc, etc.).
tion without the risk of treatment-related fouling
AEC is effective at high pH, high M-Alkalinity, and
associated with calcium phosphonate. Operating
high calcium concentrations. It is not degraded by
at higher cycles reduces makeup water and tower
halogens or temperature.
blowdown volumes, and provides water and
chemical savings:
Find a contact near you by visiting www.ge.com/water and clicking on “Contact Us”.
* Trademark of General Electric Company; may be registered in one or more countries.
©2009, General Electric Company. All rights reserved.
cp85.doc Nov-09Water savings reduced by 30-50%. The AEC molecule does not
• Lower costs for purchased makeup water contain phosphorus and replaces organic phos-
phonates used for scale control such as AMP,
• Lower costs for discharged tower blowdown HEDP, and PBTC. Lower phosphorus means easier
• Easier compliance with discharge regulations compliance with discharge regulations.
Chemical savings
Improved Safety and Reliability
• Lower costs for influent water treatment
Organic phosphonates have been the primary
• Lower costs for cooling water treatment
calcium carbonate scale inhibitors. These inhibi-
• Lower costs for wastewater treatment tors can precipitate as calcium phosphonate and
cause fouling if system upsets or product over-
Improve Operator Safety feeds occur. Phosphonates also degrade in the
Because Continuum AEC programs are designed for presence of halogens or at high temperatures,
use in alkaline waters, acid feed for cooling water which can result in scaling. AEC solubility and sta-
pH control can be reduced or eliminated. Conse- bility are superior to phosphonates, making AEC
quently, safety hazards associated with acid han- safer than organic phosphonates.
dling and acid feed equipment maintenance may be
eliminated. Simplified Response to Upsets
No matter how diligent the surveillance of the
Reduce Acid Feed Costs cooling system or how capable the control
In addition to minimizing safety hazards associated equipment, system upsets will occur. Upsets re-
with acid use, the reduction or elimination of acid sulting from loss of acid feed or over-cycling
use at the cooling tower provides savings in several cause scaling. Acid overfeeds or low cycle upsets
areas result in corrosion.
• Cost of purchased acid Continuum AEC programs are formulated to pro-
• Parts and labor for acid feed equipment mainte- vide maximum safety and flexibility when re-
nance sponding to either scaling or corrosive upsets.
Recovery procedures when using Continuum AEC
• Materials and labor to repair or replace equip- programs are easily implemented and ensure
ment damaged during acid overfeed minimal disruption of system operation.
• Improved production rates through reduced un-
AEC is the first calcium carbonate deposit control
scheduled downtime and lower fouling cleanup
agent which is safe to use at high treatment levels
costs when acid feed is lost
during periods of system upset. When alkaline pH
Avoid Increased Biocide Costs or high hardness excursions occur, feeding high
doses of AEC will safely control calcium carbonate.
AEC does not degrade in the presence of halogens
or non-oxidizing biocides, so systems treated with Because Continuum AEC programs combine an
AEC are not limited to a particular type of biocide. effective corrosion inhibitor package with a poly-
With AEC programs, biocide selection can be based meric dispersant, the same high treatment level
solely on what works most cost-effectively in your response during low pH or low cycle upsets will
system. There is no need to switch from your pre- repassivate system metallurgy while preventing
sent biocide program in order to ensure the per- equipment from fouling with corrosion byprod-
formance of your corrosion/deposition control ucts.
program.
How Does AEC Improve Current
What Does AEC Contribute to Water Treatment Programs?
Continuum Programs? Phosphonate-based calcium carbonate treat-
GE Continuum programs provide reduced phospho- ments lose efficacy and pose a fouling risk under
rus discharge compared to other phosphate pro- the following conditions:
grams. With AEC, total phosphorus is further • High pH/high M-Alkalinity
Page 2 Capability Profile• High calcium benefit from the alkaline conditions under which
• High free halogen Continuum AEC programs are applied. Azole films
ensure low yellow metal corrosion rates when oxi-
• High cycles/long retention times dizing biocides are used when low pH swings oc-
AEC is the only available calcium carbonate inhibitor cur. The latest Halogen Resistant Azole (HRA) is
to give undiminished performance under all the appropriate for all systems containing copper
above conditions. and/or copper alloys in and out of the presences
of halogens.
AEC has superior solubility and stability, which re-
duces the potential for calcium carbonate fouling or Phosphate
fouling by precipitated calcium phosphonate com-
plexes. Phosphonate-based programs may require Continuum AEC programs utilize low levels of
extra dispersant to cope with these fouling species. phosphate for added mild steel corrosion protec-
Phosphonate degradation in the presence of halo- tion in moderately alkaline waters. These phos-
gens may necessitate higher product feed rates. All phate levels are 30 to 50% lower than alkaline
of these result in higher treatment costs. By con- phosphate programs utilizing phosphonates. Low
trast, AEC’s outstanding solubility and stability char- phosphate levels provide a real advantage when
acteristics provide both cost and performance meeting strict phosphorus discharge limits. Where
advantages. phosphate discharge is altogether banned, low
levels of zinc can be fed to provide supplemental
What Are the Components of corrosion protection.
Continuum AEC programs, and How Do
Is AEC Affected By Halogens Used For
They Function?
Cooling Water Disinfection?
Alkyl Epoxy Carboxylate AEC is unaffected by halogens. Phosphonate-
AEC inhibits calcium carbonate scale and provides based calcium carbonate scale inhibitors revert in
steel corrosion protection. This unique, environmen- the presence of halogen residuals resulting in loss
tally acceptable, all organic calcium carbonate in- of fouling control. That is, the organic core mole-
hibitor provides scale control by maintaining cule degrades, inorganic phosphate is released,
calcium carbonate solubility. AEC is safer to use functionality is lost, and scale control is compro-
than phosphorus-based scale inhibitors because it mised. AEC is the only calcium carbonate inhibitor
does not form insoluble fouling complexes with cal- which does not degrade in the presence of halo-
cium. AEC also inhibits mild steel corrosion in alka- gen — even at high levels of chlorine.
line waters. Some calcium carbonate inhibitors sold by GE
competitors are so sensitive that chlorination
Polymeric Dispersant must be replaced with bromine chemistry in order
Polymeric dispersants prevent fouling due to sus- to reduce reversion and prevent loss of fouling
pended solids. In systems containing phosphate, control. AEC is resistant to halogenation and will
this latest generation polymer extends calcium provide effective calcium carbonate scale control
phosphate solubility. The polymer also contributes regardless of the halogen used for cooling water
to calcium carbonate scale control. disinfection.
Because AEC does not form insoluble precipitating Does System Retention Time Affect
complexes with calcium carbonate as do phospho-
rus-based scale inhibitors, polymer requirements AEC?
and resulting program costs are lower than conven- AEC is hydrolytically and thermally stable and is
tional alkaline phosphate programs. unaffected by long retention times. Organic phos-
phate scale inhibitors undergo reversion. High
Azole temperatures, free chlorine residual, and long
Azole provides copper alloy corrosion inhibition. residence times increase the extent of reversion.
Both yellow metal and mild steel corrosion rates AEC is the only deposit control agent which ad-
Capability Profile Page 3dresses the specific needs of systems with high re- approvals. GE has a product line specifically for
tention times. This makes Continuum AEC programs these applications.
an excellent choice for scale control in modern,
water-conserving, high cycle cooling systems. What Key Considerations Guide
Program Selection?
How Do System Upsets Affect
Continuum AEC programs should be considered
Continuum AEC Program Performance?
for any alkaline cooling water application. These
When compared to conventional alkaline programs, programs are custom designed to provide excel-
Continuum AEC programs provide an unsurpassed lent corrosion and deposit control for a variety of
margin of safety under system upset conditions. water chemistries and operating conditions. Con-
Continuum AEC programs also simplify response to sider a Continuum AEC program for any system
upsets. where low fouling potential and extended run
lengths are important.
High pH or high cycle conditions resulting from loss
of acid feed or blowdown control can cause scaling. Continuum AEC programs provide options for
Increasing tower blowdown to reduce cycles or pH situations where conventional programs are no
frequently results in corrosive water chemistry dur- longer suitable, such as in the treatment of low
ing recovery. Continuum AEC programs generate velocity, high temperature equipment currently
lower levels of phosphate so there is less risk of cal- experiencing fouling with calcium carbonate or
cium phosphate or iron phosphate fouling when pH calcium phosphonate. Systems which are re-
or blowdown control is lost. stricted to limited phosphorus discharge and sys-
tems where the use of acid has become a safety
Further, the AEC component of these programs does
concern are also prime candidates for a Contin-
not form precipitating complexes with calcium. In
uum AEC program.
high pH/high cycle upsets, product feed can be in-
creased safely to prevent scaling. Tower blowdown Your GE field representative can recommend spe-
does not have to be drastically increased, and cor- cific treatments, feedrates, and operating pa-
rosive conditions usually encountered during recov- rameters which best suit your water chemistry,
ery are avoided. system metallurgy, and plant goals.
Are Continuum AEC Programs Toxic to Do Continuum AEC Programs Require
Aquatic Organisms? Acid Feed?
Continuum AEC programs are truly environmentally Continuum AEC programs are designed for alka-
compatible. Based on toxicity values for a variety of line waters so acid feed can be reduced or elimi-
aquatic organisms, Continuum AEC programs can nated. In fact, if you want to discontinue acid use
be described as "practically non-toxic" to "slightly in your cooling system, consider a Continuum AEC
toxic". These descriptions represent some of the program as the first choice treatment. In other
lowest toxicity ratings possible. systems using high alkalinity or high calcium
makeup water, some amount of acid must be fed
Those products which are practically non-toxic had
in order to operate at economical cycles. A Con-
no effect on aquatic organisms even when fed at
tinuum AEC program can still be used to treat
levels three to five times normal use rates. Specific
these systems.
aquatic toxicity information on the Continuum AEC
program recommended for your system is available
from your GE representative. How Are Continuum AEC Programs
Applied?
Do Continuum AEC Programs Have Continuum AEC programs are stable, easily han-
Potable, FDA, or USDA Approvals? dled, and are fully compatible with most manual
and automated feed systems. Continuum AEC
No, these programs were not designed for use in
programs are applied as are most standard cool-
potable systems or systems requiring FDA or USDA
ing water treatments. These products should be
fed to a point in the cooling system where they
Page 4 Capability Profilecan rapidly mix with the bulk cooling water. For best Are Continuum AEC programs
results, Continuum AEC programs should be fed
"neat". Dilution, if necessary, is best done with low
Exclusive to GE?
hardness water. Yes, Continuum AEC programs are exclusive to GE.
GE holds several patents for the use of AEC to
Is a Continuum AEC Program control corrosion and deposition in aqueous sys-
Compatible With Existing Feed tems.
Systems?
Tanks, pumps, piping, and valves should be made of
stainless steel, polyethylene, or PVC. Equipment rec-
ommendations for specific blends are available
upon request. GE computerized feed and control
equipment, such as the PaceSetter* Plus system, are
compatible with all Continuum products. Computer-
ized feed equipment can be used to reduce system
variation and optimize treatment performance
thereby reducing overall costs and ensuring consis-
tent results.
How Are Continuum AEC Programs
Monitored?
Monitoring Continuum AEC programs should include
provisions for tracking treatment residuals as well
as program performance. Conventional orthophos-
phate testing provides a widely familiar method of
program control. The AEC molecule itself can be
measured at use levels. Some Continuum AEC pro-
grams contain a tracer to simplify tracking product
feed rates and maintain program control.
Program performance can be monitored by follow-
ing corrosion and fouling rates. Standard metallur-
gical coupons can be used to evaluate corrosion
protection. Given the wide variety of available foul-
ing monitoring techniques, your GE field representa-
tive will establish a fouling monitoring program best
suited for your system.
How Are Continuum AEC Programs
Delivered?
GE AEC programs are liquid materials and are
available in a wide variety of customized contain-
ers and delivery methods. Contact your GE rep-
resentative for details.
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