ASTM D4778-94(1999)e1
(Test Method)Standard Test Method for Determination of Corrosion and Fouling Tendency of Cooling Water Under Heat Transfer Conditions
Standard Test Method for Determination of Corrosion and Fouling Tendency of Cooling Water Under Heat Transfer Conditions
SCOPE
1.1 This test method provides directions for fabricating and operating a test apparatus to simultaneously monitor the corrosion and fouling tendency of real and pilot cooling water systems under heat transfer conditions.
1.2 Interpretation of the results of this test method must be left to the investigator. Many variables are involved which may not be easily controlled or fully understood. Variations in design and operating conditions may produce results that are not comparable from unit to unit.
1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are provided for information only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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An American National Standard
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Designation:D 4778–94 (Reapproved 1999)
Standard Test Method for
Determination of Corrosion and Fouling Tendency of
Cooling Water Under Heat Transfer Conditions
This standard is issued under the fixed designation D 4778; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
e NOTE—A footnote was editorially removed in July 1999.
1. Scope 3.2.3 heat flux— heat transfer per unit area per unit time.
1.1 This test method provides directions for fabricating and
4. Summary of Test Method
operating a test apparatus to simultaneously monitor the
4.1 Water from the system to be tested flows across a heated
corrosion and fouling tendency of real and pilot cooling water
tube of the desired metallurgy at a constant flow rate and heat
systems under heat transfer conditions.
flux. Corrosion rate is determined by weight loss while fouling
1.2 Interpretation of the results of this test method must be
tendency is determined by the deposit weight.
left to the investigator. Many variables are involved which may
not be easily controlled or fully understood. Variations in
5. Significance and Use
design and operating conditions may produce results that are
5.1 Deposits on heat transfer surfaces reduce efficiency of
not comparable from unit to unit.
the heat exchanger affected. A method for easily determining
1.3 The values stated in inch-pound units are to be regarded
the corrosion and fouling tendency of a particular water under
as the standard. The values given in parentheses are provided
heat transfer conditions will allow the evaluation of changes in
for information only.
the various system variables such as heat flux, flow velocity,
1.4 This standard does not purport to address all of the
metallurgy, cycles-of-concentration, and treatment schemes on
safety concerns, if any, associated with its use. It is the
heat exchanger performance.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
6. Apparatus (Fig. 1)
bility of regulatory limitations prior to use.
3 1
6.1 Test Specimen—Ametal tube of ⁄8 or ⁄2 in. (9.5 or 12.5
mm) outside diameter with sufficient inside diameter to snug-
2. Referenced Documents
gly accommodate the cartridge heater. The tube should be cut
2.1 ASTM Standards:
2 to a length sufficient to extend ⁄2 in. (12.5 mm) from each end
D 1129 Terminology Relating to Water
2 of the test assembly. If both corrosion and deposition are to be
D 1193 Specification for Reagent Water
determined, metallurgy of the test specimen should match that
D 2777 Practice for Determination of Precision and Bias of
2 of the heat exchanger being modeled.
Applicable Methods of Committee D-19 on Water
1 3
6.2 Cartridge Heater—A ⁄4 or ⁄8 in. (6.2 or 9.5 mm)
diameter.Heatedsurfaceshouldbe4to8in.(10to20cm)long
3. Terminology
with a minimum power rating sufficient to provide 110 % of
3.1 Definitions—For definitions of terms used in this test
the heat load required (see Eq 7, 8.2.2).The heater should have
method, refer to Terminology D 1129.
an unheated section of sufficient length to allow the center of
3.2 Definitions of Terms Specific to This Standard:
the heated section to be placed consistently in the center of the
3.2.1 corrosion— the deterioration of the metal by reaction
test specimen.
with its environment.
6.3 Power Controller— A device to set and control the
3.2.2 fouling— deposition of organic matter or inorganic
power to the heater, such as a variable transformer, is used to
matter, or both, on heat transfer surfaces that result in the loss
adjust the heat flux in order to maintain the surface temperature
of heat transfer efficiency.
of the test specimen consistent with the heat exchanger being
modeled. The power controller should be rated to maintain at
This test method is under the jurisdiction of ASTM Committee D19 on Water least 120 %, but not more than 400 % of the power required.
and is the direct responsibility of Subcommittee D19.03 on Sampling of Water and
6.4 Flow Control— A flow meter or a flow control device
Water-Formed Deposits, Surveillance of Water, and Flow Measurement of Water.
such as an orifice, or both, is recommended to maintain a
Current edition approved April 15, 1994. Published June 1994. Originally
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consistent flow rate during the test period.
published as D 4778 – 88. Last previous edition D 4778 – 88 (1993) .
Annual Book of ASTM Standards, Vol 11.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D 4778–94 (1999)
NOTE 1—All pipe is threaded 1 in. (25 mm) PVC. Heater should be
fused and grounded in accordance with local electrical codes.
FIG. 1 Test Apparatus and Parts List
Parts List:
(1) test specimen (6) acrylic tube, 10 in. (25 cm) long by 1 in. (25 mm)
outside Diameter
(2) tube fitting; nylon (no metal parts) (7) tube heater (Cartridge heaters that have been found
satisfactory for this purpose are available from Watlow,
12001 Lackland Rd., St. Louis, MO 63141.)
(3) reduci ng bushing, PVC
(4) tee, 1 in. (25 mm) PVC
(5) tube fitting, 1 in. (25 mm) tube by 1 in.
(25 mm) male pipe thread stainless steel
FIG. 2 Test Assembly and Parts List
6.5 Safety Equipment—Apressure or flow sensor/controller such specifications are available. Other grades may be used,
is necessary to cut power to the heater in the event of a flow provided it is first ascertained that the reagent is of sufficiently
high purity to permit its use without lessening the accuracy of
interruption. A high temperature cutoff is recommended for
the determinations.
added protection.
7.2 Purity of Water— Unless otherwise indicated, refer-
6.6 Test Assembly— See Fig. 2.
ences to water shall be understood to mean reagent water as
defined by Type III of Specification D 1193.
7. Reagents and Materials
7.1 Purity of Reagents—Reagent grade chemicals shall be
“ReagentChemicals,AmericanChemicalSocietySpecifications,’’Am.Chemi-
used in all tests. Unless otherwise indicated, it is intended that
cal Soc., Washington, DC. For suggestions on the testing of reagents not listed by
all reagents conform to the specifications of the Committee on
theAmerican Chemical Society, see “Analar Standards for Laboratory Chemicals,’’
Analytical Reagents of the American Chemical Society where BDH Ltd., Poole, Dorset, U. K., and the “United States Pharmacopeia.’’
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D 4778–94 (1999)
7.3 Acetone.
F = water flow rate, gal/min,
7.4 Hydrochloric Acid (HCl), Inhibited.
D = inside diameter of tube in process heat exchanger,
7.5 Isopropyl Alcohol (C H O).
in.,
3 8
7.6 Trichloroethylene. L = length of heater section, ft, and
7.7 Trisodium Phosphate —(Na PO ·12H O), also avail- N = number of tubes in process heat exchanger.
3 4 2
able as Na PO ·8H O. Either grade is satisfactory.
3 4 2 8.2.2 Calculate the test device setup as follows:
V 5 [V [D/ d 2 d
# ~ !#
8. Procedure t p 2 1
(3)
8.1 Installation of Test Device:
8.1.1 Placement of the test device with respect to the
where:
cooling water system is an important factor in monitoring
V = water velocity, ft/s,
fouling and corrosion in interpreting the test results. Fouling = test device,
t
= process,
and corrosion are both affected by temperature. In the case of
p
D = inside diameter of tube in process heat exchanger, in.,
corrosion, the higher the water temperature, the greater will be
d = inside diameter of outer tube in test device, in., and
the corrosivity of the water. Fouling, however, is a far more
d = outside diameter of inner (heated) tube in test device,
complex phenomenon, involving one or more of several types 1
in.
of foulants, namely, particulate matter, precipitates, biomass,
2 2
corrosion products, and contamination. There are five phases
F 5 2.45 V ~d 2 d !
t t 2 1
involved in the fouling phenomenon: initiation, attachment,
(4)
removal, transport, and aging.
where:
8.1.2 Several of the foulants are temperature sensitive.
F = water flow rate, gal/min,
Precipitates, such as calcium carbonate, tend to precipitate
= test device,
t
more rapidly as temperatures increase. Most biomasses, on the
V = water velocity, ft/s,
other hand, would agglomerate more rapidly at temperatures
d = inside diameter of outer tube in test device, in., and
between 90 and 105°F (32.2 and 40°C).
d = outside diameter of inner (heated) tube in test device,
8.1.3 The test device may be installed to take its inlet water
in.
from one of three locations: cold water supply to a heat
0.8
exchanger, a heat exchanger outlet, or warm water return to the W 5 9.8 ~T 2 T !V L ~1 1 0.096 T ! ~for d 5 0.50! (5)
s b b 1
cooling tower. The choice of location is a function of the type
where:
of fouling problem(s) experienced with the particular system.
W = power supplied to heater, W,
No matter where it is placed, the fouling conditions in the test
T = temperature, °F,
device should simulate the plant equipment as closely as
= surface or interface,
s
possible. Specifically, the surface
...
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