SIST EN ISO 14597:1999

SLOVENSKI STANDARD
01-november-1999
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Petroleum products - Determination of vanadium and nickel content - Wavelength-
dispersive X-ray fluorescence spectrometry (ISO 14597:1997)
Mineralölerzeugnisse - Bestimmung des Vanadium- und Nickelgehaltes -
Wellenlängedispersive Röntgenfluoreszenz-Analyse (ISO 14597:1997)
Produits pétroliers - Dosage du vanadium et du nickel - Spectrométrie de fluorescence X
dispersive en longueur d'onde (ISO 14597:1997)
Ta slovenski standard je istoveten z: EN ISO 14597:1999
ICS:
75.080 Naftni proizvodi na splošno Petroleum products in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL
IS0
STANDARD
First edition
1997-07- 15
Petroleum products - Determination of
vanadium and nickel content -
Wavelength-dispersive X-ray fluorescence
spectrometry
Produits pholiers - Dosage du vanadium et du nickel - Spectrom&rie de
fluorescence X dispersive en longueur d ’onde
Reference number
IS0 14597: 1997(E)
IS0 14597:1997(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work of
preparing International Standards is normally carried out through IS0
technical committees. Each member body interested in a subject for which
a technical committee has been established has the right to be represented
on that committee. International organizations, governmental and non-
governmental, in liaison with ISO, also take part in the work. IS0
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard IS0 14597 was prepared by Technical Committee
lSO/TC 28, Petroleum products and lubricants.
0 IS0 1997
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 l CH-1211 Geneve 20 l Switzerland
Internet
central @ isocs.iso.ch
x.400 c=ch; a=400net; p=iso; o=isocs; s=central
Printed in Switzerland
ii
IS0 14597: 1997(E)
INTERNATIONAL STANDARD @ IS0
Petroleum products - Determination of vanadium and nickel
- Wavelength-dispersive X-ray fluorescence spectrometry
content
WARNING - The use of this International Standard may involve hazardous materials, operations and
equipment. This International Standard does not purport to address all of the safety problems associated
with its use. It is the responsibility of the user of this International Standard to establish appropriate safety
and health practices and determine the applicability of regulatory limitations prior to use.
1 Scope
This International Standard specifies a method for the determination of vanadium and nickel in liquid petroleum
products. It may also be applied to semi-solid and solid petroleum products that are either liquefied by moderate
heating or completely soluble in the specified organic solvent mixture. The method is applicable to products having
vanadium contents in the range 5 mg/kg to 1 000 mg/kg, and nickel contents in the range 5 mg/kg to 100 mg/kg,
although precision data have only been determined up to 100 mg/kg for vanadium and 60 mg/kg for nickel; higher
contents may be determined by appropriate dilution.
Barium at concentrations above approximately 300 mg/kg interferes with the determination of vanadium, and iron at
concentrations above approximately 500 mg/kg interferes with the determination of nickel. Other elements at
concentrations above approximately 500 mg/kg may affect precision and accuracy due to spectral line overlap or
absorption.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this
International Standard. At the time of publication, the editions indicated were valid. All standards are subject to
revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain
registers of currently valid International Standards.
IS0 3170: 1988, Petroleum liquids - Manual sampling.
IS0 3171 :1988, Petroleum kquids - Automa tic pipeline sampling.
3 Principle
The test portion and a manganese solution as internal standard are mixed in a given mass ratio and exposed, in a
sample cell, to the primary radiation of an X-ray tube.
The count rates of excited metal and reference material are measured, and the ratio of these count rates calculated.
The vanadium and nickel contents of the sample are determined from calibration curves prepared on the basis of
calibration standards.
@ IS0
ISO14597:1997(E)
4 Reagents and materials
4.1
White oil (light paraffin oil), high purity grade, sulfur content 1 mg/kg maximum.
4.2 Xylene or mixed xylenes, analytical reagent grade.
4.3 Solvent mixture, 1 part by volume of white oil (4.1) mixed with 2 parts by volume of xylene (4.2).
4.4 Acetyl acetone, minimum purity 99 % (m/m).
NOTE - For the purposes of this International Standard, the expressions “% (I&Z)” and “% (V/V)” are used to represent the
mass and volume fractions respectively.
4.5 2-ethylhexanoic acid, minimum purity 98 % (m/m).
4.6
Vanadium compound, bis (1 -phenylbutane-1 , 3-dionato)-oxo-vanadium(W) or any other oil-soluble vanadium
compound. The vanadium content shall be accurately known to the nearest 0,Ol % (m/m).
4.7 Nickel compound, cyclohexane butanoic acid-nickel salts or any other oil-soluble nickel compound. The
nickel content shall be accurately known to the nearest 0,Ol % (m/m).
nd. The manganese
4.8 Manganese compound, manganese octoate or any other oil-soluble manganese compou
content shall be approximately 10% (m/m).
NOTE - Manganese compounds may contain insoluble impurities entrapped during manufacture, e.g. oxides. If this is
evident, the compound should be cleaned by dissolution in petroleum spirit, boiling range 60 “C to 80 “C, followed by filtration
and evaporation.
4.9 Manganese solution.
Dissolve the manganese compound (4.8) in a solution of 95 % (V/V) solvent mixture (4.3) and 5 % (V/V)
2-ethylhexanoic acid (4.5) to produce a manganese content of approximately 500 mg/kg [0,05 % (m/m)]. Store the
solution in a tightly-stoppered brown glass bottle protected from light within the temperature range of 18 “C to 28 “C.
NOTE - Under these conditions, the solution is stable for at least 3 months.
4.10 Certified reference standards, use materials from a national standards body or accredited suppliers, if
available.
5 Apparatus
5.1 Wavelength-dispersive X-ray fluorescence spectrometer, use any suitable X-ray spectrometer capable of
being operated under the conditions in table 1 and of measuring the wavelengths in table 2, or other giving
equivalent results. It shall be set up according to the manufacturer ’s instructions.
5.2 Analytical balance, capable of weighing to the nearest 0,l mg.
5.3 Homogenizer, of non-aerating, high speed shear type or heatable magnetic or ultrasonic stirrer.
5.4 Flasks, of 50 ml capacity, narrow-necked, conical, made of borosilicate glass and fitted with ground-glass
stoppers.
@ IS0 IS0 14597: 1997(E)
Table 1 - General requirements of spectrometer
Requirement
Component
Anode Any tube anode may be used provided that the counting times be adjusted
to achieve the required precisionl)
Set to provide maximum sensitivity for the lines in table 2 and within the
Tube voltage and current
power rating of the spectrometer.
Lithium fluoride (LiF) or any other crystal suitable for the dispersion of the
Analyzing cristal
wavelengths in table 2 within the angular range of the spectrometer
Helium
Optical path
Gas proportional detector with pulse-height analyser
Detector
1) If a chromium anode is used, either measure the Mn-KB line (0,191 0 nm) and IUMn at 0,188 5 nm, or measure the
Mn-K, line (0,210 3 nm) with a suitable tube filter to eliminate spectral interference from the Cr-KB line and IUMn at
0,219 0 nm.
6 Samples and sampling
6.1 Unless otherwise specified, samples shall be taken by the procedures described in IS0 3170 or IS0 3171.
6.2 Test portions from the samples shall be drawn after thorough mixing subdivision. Heat viscous, opaque, semi-
solid or solid samples to a temperature which renders the sample liquid and homogenize using the homogenizer
(5.3).
NOTE - Stratification in the sample cell, either of water or asphaltenic material, can lead to erroneous results.
7 Calibration solutions
7.1 General
Use either certified reference materials (4.10) or primary standards prepared from metal compounds (4.6 and 4.7)
prepared as described in 7.2 as a basis for the preparation of stock solutions.
7.2 Preparation of stock solutions
7.2.1 Vanadium stock solutions
Weigh, to the nearest 0,l mg, a quantity (m') of vanadium compound (4.6) to prepare stock solutions of
approximately 1 000 mg/kg [O,lO % (m/m)] and 200 mg/kg [0,02 % (m/m)] vanadium content. Dissolve each of these
in a mixture of 98,5 % (V/V) solvent mixture (4.3) and 1,5 % (V/V) acetyl acetone (4.4) and then weigh the solution
to the nearest 0,l mg (m' + m"). Mix the contents thoroughly using a homogenizer (5.3) and transfer to a tightly-
stoppered brown glass bottle.
Calculate the exact vanadium content, Wv2, in mg/kg, to the nearest 1 mg/kg, from the mass of vanadium
compound and mass of liquid using the following equation:
m'xWvj
. . .
WV2 = (1)
m'+-m"
where
m' is the mass, in grams, of the vanadium compound;

IS0 14597: 1997(E) @ IS0
Wvl is the vanadium content, in milligrams per kilogram, of the vanadium compound;
m" is the mass, in grams, of the solvent liquid.
shelf life and as soon as
NOTE - The stock solutions have a limited turbidity is evident they be discarded in an
environmentally acceptable manner.
7.2.2 Nickel stock solution
Weigh, to the nearest 0,l mg, a quantity (m') of nickel compound (4.7) to prepare a stock solution of approximately
100 mg/kg [O,Ol % (m/m)] nickel content. Dissolve this in a mixture of 95 % (V/v> solvent mixture (4.3) and 5 % (V/V)
of 2-ethylhexanoic acid (4.5) and then weigh the solution to the nearest 0,l mg (m' + m"). Mix the contents
thoroughly using a homogenizer (5.3) and transfer to a tightly-stoppered brown glass bottle.
Calculate the exact nickel content, WNQ, in mg/kg, to the nearest 1 mg/kg, from the mass of nickel compound and
mass of liquid using the following equation:
m’ X WNil
. . .
(2)
wNi2 =
m'+m"
m' is the mass, in grams, of nickel compound;
WNil is the nickel content, in milligrams per kilogram, of the nickel compound;
mN is the mass, in grams, of the solvent liquid.
7.3 Preparation of standard solutions
7.3.1 High range vanadium
Into 50 ml flasks (5.4), weigh to the nearest 0,l mg, the appropriate quantity of the 1 000 mg/kg vanadium stock
solution (7.2.1) to produce approximately 25 g of each standard solution with vanadium contents of approximately
800 mg/kg, 600 mg/kg, 500 mg/kg, 400 mg/kg and 300 mg/kg. Add solvent mixture (4.3) to make up to
approximately 25 g and re-weigh to the nearest 0,l mg. Calculate the vanadium content, Wv3, in mg/kg, of each
standard solution to the nearest 1 mg/kg, using the following equation:
m2 - ml )w/2
(
. . .
WV3 = (3)
m3 - ml
is the mass, in grams, of the flask;
ml
is the mass, in grams, of the flask plus stock solution;
is the mass, in grams, of the flask plus stock solution plus solvent mixture;
m3
is the vanadium content, in milligrams per kilogram, of the stock solution.
WV2
NOTE - Dissolution and mixing is aided by the use of the homogenizer (5.3) and mild heat.
7.3.2 Low range vanadium
Prepare standard solutions as described in 7.3.1 using the 200 mg/kg stock solution (7.2.1) to give standard
solutions of approximately 175 mg/kg, 150 mg/kg, 125 mg/kg, 100 mg/kg, 75 mg/kg, 50 mg/kg, 25 mg/kg and
5 mg/kg. Calculate the vanadium content to the nearest 1 mg/kg using equation (3) given in 7.3.1.

@ IS0 IS0 14597:1997(E)
7.3.3 Nickel
Prepare standard solutions as described in 7.3.1 using the nickel stock solution (7.2.2) to give standard solutions of
approximately 75 mg/kg, 50 mg/kg, 25 mg/kg, 10 mg/kg and 5 mg/kg.
7.4 Preparation of calibration solutions
7.4.1 Preparation
Weigh 20,OO g + 0,Ol g of each of the standard solutions (7.3) and the stock solutions (7.2) into separate flasks
(5.4), and add 2,00 g + 0,Ol g of the manganese solution (4.9). Mix, using the homogenizer (5.3) at a maximum
temperature of 50 “C, and cool to a temperature of 18 “C to 28 “C. Transfer to tightly-stoppered brown glass bottles.
7.4.2 Storage
Store certified reference standards in accordance with the instructions of the certifying organization and use within
the timescale specified.
Store standards prepared from solvent mixture and standard solutions in a cool dark place.
NOTE - The stability of prepared standards, under the above storage conditions, has been found to exceed three months.
8 Calibration
8.1 General
After the spectrometer has been set up and checked (5.1) purge the optical path thoroughly with helium.
8.2 Calibration curves
Transfer each of the calibration solutions (7.4.1) to a sample cell and, in a sequence of increasing metal content,
place them in the spectrometer for exposure to the primary radiation. Measure the count rates, I, of the excited
V-K,, Ni-K,, Mn-K, or Mn-KS, and also the respective background radiations, ZU, at the wavelengths given in
table 2.
Table 2 - Wavelengths of X-ray fluorescence and background radiation
Wavelength
Element
nm
0,250 5
Vanadium, IV
0,239
Vanadium background, IUV
0,165 9
Nickel, INi
0,163 8
Nickel background, ZUNi
Manganese, 1~”
0,210 4
a) Mn-K,
0,190
b) Mn-KP
0,219 0
Manganese background, IUMn
@ IS0
IS0 14597:1997(E)
The setting of the spectrometer shall be such that at least 50 000 counts are registered for the Mn-K, or Mn-Kp line
over the measurement period. In addition, the measuring time for each element shall be sufficient to achieve a
coefficient of variation of less than 1 % at the top concentration levels (WV = 1 000 mg/kg, WNi = 100 mg/kg). The
coefficient of variation, c, is calculated from the following equation:
loo,/Np + Nb
c= . . .
(NP +Nb)
is the number of counts collected on the Ni-K, (INi) or V-K, (Iv) peak;
NP
is the number of counts collected at the relevant background wavelength (zu).
Nb
If the peak to background ratio, Z:Zu, is greater than lO:l, formula (4a) reduces to
c=-
. . .
w
NP
II-
For a coefficient of variation of 1 %, formula (4b) gives Np equal to 10 000.
The measuring time, 7 ’P, for the elements, or &, for background is calculated from the following equations:
NP
=-
. . . a
(5 )
TP
RP
. . .
(5b)
Tb
is either ZNi or ZV;
RP
is ZU.
Rb
The times calculated from the above equations shall generally be regarded as minimum times. Rounding to
practical time intervals shall be to the nearest longer time.
The net count ratio, Ro, for vanadium and nickel calibration solutions is calculated using the following general
equation:
z - zu
R. = . . .
(6)
IMn - lUMn
Z is 1~ or ZNi as appropriate;
is ZUV or ZUNi as appropriate.
Calibration curves (see note to clause 10) are constructed by plotting the net count ratio, Ro, against metal content,
mg/kg, of the calibration solutions. Two vanadium curves, covering the range 200 mg/kg to 1 000 mg/kg, and
5 mg/kg to 200 mg/kg, and one nickel curve covering the range 5 mg/kg to 100 mg/kg shall be constructed.
@ IS0
IS0 14597: 1997(E)
8.3 Checking
In regular use, check at least two points on each calibration curve not less frequently than monthly. Fuller checks
shall be carried out at intervals not greater than six months. If the check result differs from the curve by more than
the repeatability of this International Standard, a new calibration curve shall be constructed.
9 Procedure
Weigh 20,OO g + 0,Ol g of the sample to be analyzed (see note 1) into a flask (5.4) and add 2,00 g f 0,Ol g of the
manganese solution (4.9). Mix, using the homogenizer (5.3) at a maximum temperature of 80 OC. Cool to a
temperature of 18 OC to 28 “C and transfer a test portion to a sample cell. Measure the count rates for excited and
background radiations and calculate the net count ratio, Ro, in the manner described in 8.2 [equation (6)].
NOTES
1 For the purpose of this procedure, the term “sample” includes solutions prepared from additives, semi-solid or solid
roleum products that Ire-treated and/or diluted.
have been appropriately p
Pet
2 If the test portion solidifies on cooling, the measured results will not be noticeably affected, as the density change is
compensated by the internal manganese standard.
10 Calculation
Read the vanadium and nickel contents from the calibration curves constructed in 8.2. If the vanadium content is
above 1 000 mg/kg, or the nickel content is above 100 mg/kg, dilute the sample with solvent mixture (4.3) and
repeat the procedure specified in clause 9.
NOTE - Modern instruments include a computer system stores the calibration curves and calculates and produces a
digital readout of the concentration values.
11 Expression of results
Report the vanadium content, in mg/kg, to the nearest 1 mg/kg if below 200 mg/kg, and to the nearest 5 mg/kg if
between 200 mg/kg and 1 000 mg/kg. Report the nickel content to the nearest 1 mg/kg.
12 Precision
12.1 Repeatability
The difference between successive test results obtained by the same operator with the same apparatus under
constant operating conditions on identical test material would, in the normal and correct operation of the test
method, exceed the values in table 3 in only one case in twenty.
12.2 Reproducibility
The difference between two single and independent test results obtained by different operators working in different
laboratories on nominally identical test material would, in the normal and correct operation of the test method,
exceed the values in table 3 in only one case in twenty.

IS0 14597: 1997(E) @ IS0
Table 3 - Precision data
Range Repeatability Repro
...