ASTM D4006-81(2000)e1

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
An American National Standard
e1
Designation:D4006–81(Reapproved 2000)
Designation: Manual of Petroleum Measurement Standards, Chapter 10.2 (MPMS)
Designation: IP 358/97
Standard Test Method for
Water in Crude Oil by Distillation
This standard is issued under the fixed designation D4006; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This test method has been approved by the sponsoring committees and accepted by the Cooperating Societies in accordance with
established procedures. This method was issued as a joint ASTM-API-IP standard in 1981.
This standard has been approved for use by agencies of the Department of Defense.
e NOTE—Editorial corrections made throughout in April 2000.
1. Scope Water by Distillation
2.2 API Standards:
1.1 This test method covers the determination of water in
MPMS 8 “Sampling Petroleum and Petroleum Products”
crude oil by distillation.
1.2 This standard does not purport to address all of the
3. Summary of Test Method
safety concerns, if any, associated with its use. It is the
3.1 The sample is heated under reflux conditions with a
responsibility of the user of this standard to establish appro-
waterimmisciblesolventwhichco-distillswiththewaterinthe
priate safety and health practices and determine the applica-
sample. Condensed solvent and water are continuously sepa-
bility of regulatory limitations prior to use. For specific
ratedinatrap—thewatersettlesinthegraduatedsectionofthe
precautionary statements, see 6.1 and A1.1.
trap, and the solvent returns to the distillation flask.
2. Referenced Documents
4. Significance and Use
2.1 ASTM Standards:
4.1 A knowledge of the water content of crude oil is
D95 Test Method for Water in Petroleum Products and
2 important in the refining, purchase, sale, or transfer of crude
Bituminous Materials by Distillation
oils.
D96 Test Methods forWater and Sediment in Crude Oil by
Centrifuge Method (Field Procedure)
5. Apparatus
D473 Test Method for Sediment in Crude Oils and Fuel
5.1 The preferred apparatus, shown in Fig. 1, consists of a
Oils by the Extraction Method
glassdistillationflask,acondenser,agraduatedglasstrap, and
D665 Test Method for Rust-Preventing Characteristics of
a heater. Other types of distillation apparatus are specified in
Inhibited Mineral Oil in the Presence of Water
Specification E123.Any of these apparatus will be acceptable
D1796 Test Method for Water and Sediment in Fuel Oils
for this method provided it can be demonstrated that they
by the Centrifuge Method (Laboratory Procedure)
operate within the precision established with the preferred
D4057 Practice for Manual Sampling of Petroleum and
3 apparatus.
Petroleum Products
5.1.1 Distillation Flask—A 1000-mL round-bottom, glass,
D4177 Practice for Automatic Sampling of Petroleum and
3 distillation flask fitted with a 24/40 female taper joint shall be
Petroleum Products
used. This flask receives a 5-mL Specification E123 Type E
E 123 Specification for Apparatus for Determination of
calibrated,graduatedwatertrapwith0.05-mLgraduations.The
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee Annual Book of ASTM Standards, Vol 14.04.
D02.02 on Static Petroleum Measurement. Available from the American Petroleum Institute, 1220 L St., N.W., Washing-
Current edition approved March 27, 1981. Published May 1981. ton, DC 20005.
2 6
Annual Book of ASTM Standards, Vol 05.01. Available on special order from Scientific Glass Apparatus Co., Bloomfield,
Annual Book of ASTM Standards, Vol 05.02. N.J. 07003.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
e1
D4006–81 (2000)
7. Sampling, Test Samples, and Test Units
7.1 Sampling is defined as all steps required to obtain an
aliquotofthecontentsofanypipe,tank,orothersystemandto
place the sample into the laboratory test container.
7.1.1 Laboratory Sample—Only representative samples ob-
tainedasspecifiedinPracticeD4057andMethodD4177shall
be used for this method.
7.1.2 Preparation of Test Samples—The following sample
handling procedure shall apply in addition to those covered in
7.1.1.
7.1.2.1 The sample size shall be selected as indicated below
based on the expected water content of the sample:
Expected Water Content, Approximate Sample Size,
weight or volume % gormL
50.1–100.0 5
25.1– 50.0 10
10.1– 25.0 20
5.1– 10.0 50
1.1– 5.0 100
0.5– 1.0 200
less than 0.5 200
If there is any doubt about the uniformity of the mixed
sample, determinations should be made on at least three test
portions and the average result reported as the water content.
7.1.2.2 To determine water on a volume basis, measure
mobile liquids in a 5, 10, 20, 50, 100, or 200-mL calibrated,
graduated cylinder (NBS Class A) depending on the sample
size indicated in 7.1.2.1. Take care to pour the sample slowly
FIG. 1 Distillation Apparatus
into the graduated cylinder to avoid entrapment of air and to
adjust the level as closely as possible to the appropriate
trap will be fitted with a 400-mm Liebig condenser. A drying
graduation. Carefully pour the contents of the cylinder into the
tube filled with desiccant (to prevent entrance of atmospheric
distillation flask and rinse the cylinder with at least 200 mLof
moisture) is placed on top of the condenser.
xylene in five steps of 40 mLand add the rinsings to the flask.
5.1.2 Heater—Any suitable gas or electric heater that can
Drain the cylinder thoroughly to ensure complete sample
uniformly distribute heat to the entire lower half of the flask
transfer.
may be used.An electric heating mantle is preferred for safety
7.1.2.3 To determine water on a mass basis, weigh a test
reasons.
portion of sample in accordance with 7.1.2.1, pouring the
5.1.3 The apparatus used in this test will be accepted when
sample directly into the distillation flask. If a transfer vessel
satisfactory results are obtained by the calibration technique
(beaker or cylinder) must be used, rinse it with at least five
described in Section 9.
portions of xylene and add the rinsings to the flask.
6. Solvent
8. Calibration
6.1 Xylene (Warning—Extremely Flammable. Vapor
8.1 Calibrate both the trap and the entire assembly prior to
harmful.),reagentgrade.Asolventblankwillbeestablishedby
use as indicated in 8.1.1-8.1.3.
placing 400 mL of solvent in the distillation apparatus and
8.1.1 Verify the accuracy of the graduation marks on the
testing as outlined in Section 10.The blank will be determined
trap by adding 0.05-mLincrements of distilled water, at 20°C,
tothenearest0.025mLandusedtocorrectthevolumeofwater
from a 5-mLmicroburet or a precision micro-pipet readable to
in the trap as in Section 11.
the nearest 0.01 mL. If there is a deviation of more than 0.050
6.2 Thexyleneusedinthisprocedureisgenerallyamixture
mL between the water added and water observed, reject the
of ortho, meta, and para isomers and may contain some ethyl
trap or recalibrate.
benzene. The typical characteristics for this reagent are:
8.1.2 Also calibrate the entire apparatus. Put 400 mLof dry
Color (APHA) not more than 10
Boiling range 137–144°C (0.02% water maximum) xylene in the apparatus and test in
Residue after evaporation 0.002 %
accordance with Section 9. When complete, discard the con-
Sulfur compounds (as S) 0.003 %
tentsofthetrapandadd1.00 60.01mLofdistilledwaterfrom
Substances darkened by H SO Color pass test
2 4
Water (H O) 0.02 % the buret or micro-pipet, at 20°C, directly to the distillation
Heavy metals (as Pb) 0.1 ppm
flask and test in accordance with Section 9. Repeat 8.1.2 and
Copper (Cu) 0.1 ppm
add 4.50 6 0.01 mL directly to the flask.The assembly of the
Iron (Fe) 0.1 ppm
Nickel (Ni) 0.1 ppm
apparatus is satisfactory only if trap readings are within the
Silver (Ag) 0.1 ppm
tolerances specified here:
e1
D4006–81 (2000)
Repeatthisprocedureuntilnowaterisvisibleinthecondenser
Limits Capacity Volume of Water Permissible for
of Trap at 20°C, Added at 20°C, Recovered Water
andthevolumeofwaterinthetrapremainsconstantforatleast
mL mL at 20°C, mL
5 min. If this procedure does not dislodge the water, use the
5.00 1.00 1.006 0.025
TFE-fluorocarbonscraper,pick(Fig.2),orequivalentdeviceto
5.00 4.50 4.50 6 0.025
cause the water to run into the trap.
8.1.3 A reading outside the limits suggests malfunctioning
9.5 Whenthecarry-overofwateriscomplete,allowthetrap
due to vapor leaks, too rapid boiling, inaccuracies in gradua-
and contents to cool to 20°C. Dislodge any drops of water
tions of the trap, or ingress of extraneous moisture. These
adhering to the sides of the trap with the TFE-fluorocarbon
malfunctions must be eliminated before repeating 8.1.2.
scraper or pick and transfer them to the water layer. Read the
volume of the water in the trap. The trap is graduated in
9. Procedure
0.05-mLincrements, but the volume is estimated to the nearest
9.1 The precision of this method can be affected by water
0.025 mL.
dropletsadheringtosurfacesintheapparatusandthereforenot
10. Calculation
settling into the water trap to be measured. To minimize the
problem, all apparatus must be chemically cleaned at least 10.1 Calculate the water in the sample as follows:
daily to remove surface films and debris which hinder free
~A– B!
Volume% 5 3100 (1)
drainage of water in the test apparatus. More frequent cleaning
C
is recommended if the nature of the samples being run causes
~A– B!
persistent contamination.
Volume% 5 3100 (2)
M/D
~ !
9.2 To determine water on a volume basis, proceed as
~A– B!
indicated in 7.1.2.2.Add sufficient xylene to the flask to make
Mass% 5 3100 (3)
M
the total xylene volume 400 mL.
9.2.1 To determine water on a mass basis, proceed as
where:
indicated in 7.1.2.3.Add sufficient xylene to the flask to make
A = mL of water in trap,
the total xylene volume 400 mL.
B = mL of solvent blank,
9.2.2 A magnetic stirrer is the most effective device to
C = mL of test sample,
reduce bumping. Glass beads or other boiling aids, although M = g of test sample, and
D = density of sample, g/mL.
less effective, have been found to be useful.
Volatile water-soluble material, if present, may be
9.3 AssembletheapparatusasshowninFig.1,makingsure
measured as water.
all connections are vapor and liquid-tight. It is recommended
that glass joints not be greased. Insert a drying tube containing
11. Report
anindicatingdesiccantintotheendofthecondensertoprevent
11.1 Report the result as the water content to the nearest
condensation of atmospheric moisture inside the condenser.
0.025% and reference this Test Method D4006 as the proce-
Circulate water, between 20 and 25°C, through the condenser
dure used.
jacket.
9.4 Apply heat to the flask. The type of crude oil being
12. Precision and Bias
evaluated can significantly alter the boiling characteristics of
12.1 The precision of this test method, as obtained by
the crude-solvent mixture. Heat should be applied slowly
statistical examination of interlaboratory test results in the
during the initial stages of the distillation (approximately ⁄2to
range from 0.01 to 1.0%, is described in 12.1.1 and 12.1.3.
1 h) to prevent bumping and possible loss of water from the
12.1.1 Repeatability—The difference between successive
system. [Condensate shall not proceed higher than three
test results, obtained by the same operator with the same
quartersofthedistanceupthecondenserinnertube(Point Ain
apparatus under constant operating conditions on identical test
Fig. 1). To facilitate condenser wash down, the condensate
material, would, in the long run, in the normal and correct
should be held as close as possible to the condenser outlet.]
operation of the test method, exceed the following value in
After the initial heating, adjust the rate of boiling so that the
only one case in twenty:
condensate proceeds no more than three quarters of the
From 0.0 % to 0.1 % water, see Fig. 3.
distance up the condenser inner tube. Distillate should dis-
Greater than 0.1 % water, repeatability is constant at 0.08.
chargeintothetrapattherateofapproximately2to5dropsper
12.1.2 Reproducibility—The difference between the two
second. Continue distillation until no water is visible in any
single and independent test results obtained by different
part of the apparatus, except in the trap, and the volume of
operators working in different laboratories on identical test
water in the trap remains constant for at least 5 min. If there is
material, would, in the long run, in the normal and correct
a persistent accumulation of water droplets in the condenser
operation of the test method, exceed the following value in
inner tube, flush with xylene. (A jet spray washing tube, see
only one case in twenty:
Fig. 2, or equivalent device is recommended.) The addition of
From 0.0 % to 0.1 % water, see Fig. 3
anoil-solubleemulsionbreakerataconcentrationof1000ppm
Greater than 0.1 % water, reproducibility is constant at 0.11.
to the xylene wash helps dislodge the clinging water drops.
13. Keywords
Afterflushing,redistillforatleast5min(theheatmustbeshut
off at least 15 min prior to wash-down to prevent bumping.) 13.1 apparatus; calibration; crude oil; distillation; proce-
After wash-down, apply heat slowly to prevent bumping. dure; sampling; solvent; water
e1
D4006–81 (2000)
FIG. 2 Pick, Scraper, and Jet Spray Tube for Distillation Apparatus
e1
D4006–81 (2000)
FIG. 3 Basic Sediment and Water Precision
ANNEX
(Mandatory Information)
A1. PRECAUTIONARY STATEMENT
A1.1 Xylene—Precaution Use with adequate ventilation.
Avoid breathing of vapor or spray mist.
Keep away from heat, sparks, and open flame.
Avoid prolonged or repeated contact with skin.
Keep container closed.
APPENDIX
(Nonmandatory Information)
X1. PRECISION AND BIAS OF METHODS FOR DETERMINING WATER IN CRUDE OILS
X1.1 Summary X1.2 Introduction
X1.2.1 In view of the economic importance of measuring
X1.1.1 Thisround-robintestingprogramhasshownthatthe
the water content of crude oils precisely and accurately, a
distillation method as practiced is somewhat more accurate
working group of API/ASTM Joint Committee on Static
than the centrifuge method. The average correction for the
Petroleum Measurement (COSM) undertook the evaluation of
distillation method is about 0.06, whereas the centrifuge
two methods for determining water in crudes. A distillation
correction is about 0.10. However, this correction is not
...