1 Supplementary Comparison COOMET.QM-S4 “С2-С5 components in mixtures of liquified hydrocarbons” Final report L.A. Konopelko 1 , Y.A. Kustikov 1 , A.V. Kolobova 1 , A. V. Meshkov 1 , O V Efremova 1 , M. Rozh- nov 2 , D. Melnyk 2 , S. Kisel 2 , O. Levbarg 2 , S. Shpilnyi 2 , S. Yakubov 2 , A.M. Mironchik 3 , M.V. Mokhnach 3 , V.N. Ananyin 3 . 1 D.I.Mendeleyev Institute for Metrology, 19, Moskovsky pr., St-Petersburg, 190005, Russia. 2 All-Ukrainian State Research and Production Center of Standardization, Metrology, Certifi- cation and Consumers Rights Protection, 4, Metrologicheskaya str., Kiev, 03143, Ukraine. 3 Belorussian State Institute for Metrology, Section for physico-chemical and optical measure- ments, sector for standards and gas mixtures, 8, Serova st., Minsk, Belarus. Field Amount of substance Subject Comparison of the composition of liquefied petroleum gas (С2-С5 components) Table of contents Field ............................................................................................................................ 1 Subject ........................................................................................................................ 1 Table of contents ........................................................................................................ 1 1 Introduction ............................................................................................................. 2 2 Design and organisation of comparison .................................................................. 2 2.1 Participants ……...................................................................................................2 2.2 Measurement standards………………………………………………………….2 2.3 The schedule……………………………………………………………………..3 2.4 Measurement methods and calibration procedures………………………..…….3 3 Results ..................................................................................................................... 4 4 Supported CMC claims ........................................................................................... 8 5 Discussion and conclusions ..................................................................................... 8 6 References ............................................................................................................... 8 Annex A – Purity data……………………………………………………………….9 Annex B - Calculation of reference values accounting for possible instability ……11 Annex C – Measurement reports from participants Measurement report from BelGIM.................................................................. 15 Measurement report from Ukrmetrteststandard .............................................. 21 Measurement report from VNIIM ................................................................... 26
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1
Supplementary Comparison COOMET.QM-S4
“С2-С5 components in mixtures of liquified hydrocarbons”
Final report L.A. Konopelko1, Y.A. Kustikov1, A.V. Kolobova1, A. V. Meshkov1, O V Efremova1, M. Rozh-
nov2, D. Melnyk2, S. Kisel2, O. Levbarg2, S. Shpilnyi2, S. Yakubov2, A.M. Mironchik3, M.V.
Mokhnach3, V.N. Ananyin3.
1D.I.Mendeleyev Institute for Metrology, 19, Moskovsky pr., St-Petersburg, 190005, Russia.
2All-Ukrainian State Research and Production Center of Standardization, Metrology, Certifi-
cation and Consumers Rights Protection, 4, Metrologicheskaya str., Kiev, 03143, Ukraine. 3Belorussian State Institute for Metrology, Section for physico-chemical and optical measure-
ments, sector for standards and gas mixtures, 8, Serova st., Minsk, Belarus.
Field Amount of substance
Subject Comparison of the composition of liquefied petroleum gas (С2-С5 components)
Table of contents Field ............................................................................................................................ 1
Note: x – mole fraction, u(x) – absolute standard uncertainty
Purity tables for parent gases used for PSGM preparation for are given below.
Purity table for propane C3H8
Component Mole fraction, µmol/mol Standard uncertainty,
µmol/mol
C3H8 999677 13
C2H6 254 12
n-C4H10 10,1 0,5
iso-C4H10 8,0 0,4
N2 41 4
O2 10 1
Purity table for ethane C2H6
Component Mole fraction, µmol/mol Standard uncertainty,
µmol/mol
C2H6 999996 0,4
CH4 0,31 0,03
C3H8 0,37 0,04
N2 2,2 0,4
O2 1,0 0,2
Purity table for propene C3H6
Component Mole fraction, µmol/mol Standard uncertainty,
µmol/mol
C3H6 995568 118
C3H8 3831 115
C2H6 460 23
C2H4 127 6
CH4 3,2 0,2
N2 8,2 0,8
O2 2,4 0,5
24
Purity table for n-butane n-C4H10
Component Mole fraction, µmol/mol Standard uncertainty,
µmol/mol
n-C4H10 995249 85
C3H8 240 12
C2H6 12,0 2,4
iso-C4H10 2450 74
iso-C5H12 17,0 0,8
neo-C5H12 680 34
C6H14 299 15
CH4 90 5
O2 43 4
N2 920 18
Purity table for iso-butane iso-C4H10
Component Mole fraction, µmol/mol Standard uncertainty,
µmol/mol
iso-C4H10 994523 108
C3H8 2800 84
C2H6 495 25
n-C4H10 2100 63 1-C4H8 41 2
CH4 18,0 0,9
iso-C5H12 1,0 0,1
СO2 22 2,2
Purity table for iso-pentane iso-C5H12
Component Mole fraction, µmol/mol Standard uncertainty,
µmol/mol
iso-C5H12 995390 220
n-C5H12 4400 220
neo-C5H12 210 10
Purity table for 1-butene 1-C4H8
Component Mole fraction, µmol/mol Standard uncertainty,
µmol/mol
1-C4H8 990340 192
iso-C4H8 2120 64
iso-C4H10 1710 51
n-C4H10 5830 174
25
Purity table for nitrogen N2
Component Mole fraction, µmol/mol Standard uncertainty,
µmol/mol
N2 999864 6
O2 3,0 0,3
CO2 0,10 0,03
Ar 132 6
H2O 1,3 0,1
Calibration and measurement
Gas chromatograph was calibrated according to ISO 6143 with the PSGMs (PSGM-1,
PSGM-2, PSGM-3). Analysis functions to determine the analytes content in the sample were taken
linear:
x(y) = b1y + b0
The gas mixture was analysed by comparison method according to ISO 6143. Four com-
parisons were made in reproducibility conditions (on different days).
Measurement sequence:
PSGM-1 х 4;
PSGM-2 х 4;
COOMET mixture (diluted with nitrogen) х 4;
PSGM-3 х 4.
Thus, each measurement included 4 replicates.
Sample handling
Gas mixtures were handled in accordance with ISO 16664.
The cylinders had been kept for 24 hrs at the room where the measurements were made.
The room was thermostatted at t = (20 ± 2) ºС.
Uncertainty evaluation
Composition of the gravimetrically prepared primary standard gas mixtures and its uncer-
tainty were calculated according to ISO 6142-1 and ISO 19229.
Results of analysis by comparison method and their uncertainty were calculated according
to ISO 6143, taking into account the uncertainties of the measuring system response, analysis
functions and primary standard gas mixtures. Calculations were made with B_LEAST software.
Uncertainties of components mole fractions normalised to 100 % of the hydrocarbons were
calculated according to ISO 6974-2.
For uncertainty evaluation the typical relative standard deviations in measurements by
comparison method were taken as they are more representative than smaller deviations obtained
in this comparison. Besides, the values of combined uncertainty were increased with regard to
possible influence of LPG sample evaporation procedure.
Participants: M. Rozhnov, D. Melnyk, S. Kisel, O. Levbarg, S. Shpilnyi, S. Yakubov
26
Report of VNIIM
КООМЕТ № 622/RU/13)
Supplementary comparison “С2-С5 components in mixtures of liquified hydrocar-
bons”
MEASUREMENT REPORT
I. Results of study
Laboratory:D.I. Mendeleyev Institute for Metrology (VNIIM)
Cylinder number: 1306
Measurement № 1
Date dd/mm/yy
Result (mol/mol) Standard deviation
(% relative)
Number of sub meas-urements,
n
Ethane 29/03/2017 2,0097 0,421 4
Propene 29/03/2017 8,8584 0,103 4
n-Butane 29/03/2017 10,1344 0,221 4
1-Butene 29/03/2017 2,9846 0,137 4
i-Butane 29/03/2017 4,0397 0,114 4
i-Pentane 29/03/2017 0,9985 0,463 4
Propane 29/03/2017 70,975 0,063 4
Measurement № 2
Date dd/mm/yy
Result (mol/mol) Standard deviation
(% relative)
Number of sub meas-urements
n
Ethane 02/04/2017 2,0329 0,293 7
Propene 02/04/2017 8,8912 0,067 7
n-Butane 02/04/2017 10,0562 0,151 7
1-Butene 02/04/2017 2,9751 0,114 7
i-Butane 02/04/2017 4,0216 0,126 7
i-Pentane 02/04/2017 0,9900 0,184 7
Propane 02/04/2017 71,032 0,041 7
Measurement № 3
Date
dd/mm/yy Result (mol/mol)
Standard deviation
(% relative)
Number of sub meas-
urements
n
Ethane 04/04/2017 2,0040 0,129 5
Propene 04/04/2017 8,8502 0,057 5
n-Butane 04/04/2017 10,1989 0,143 5
1-Butene 04/04/2017 2,9887 0,109 5
i-Butane 04/04/2017 4,0537 0,078 5
i-Pentane 04/04/2017 1,0003 0,280 5
Propane 04/04/2017 70,9043 0,043 5
27
Final results:
Component
Result
(assigned value),
cmol/mol
mol/mol
Coverage factor
Assigned expanded uncer-
tainty
cmol/mol
Ethane 2,016 2 0,018
Propene 8,867 2 0,028
n-Butane 10,130 2 0,050
1-Butene 2,983 2 0,012
i-Butane 4,038 2 0,016
i-Pentane 0,996 2 0,010
Propane 70,97 2 0,14
II. Description of study Instrument
The measurements were performed on GC system «Crystal-5000.2» (Chromatec, Russia) Data collection: Software “Chromatec Analytic 2.6” Detector: FID
Column: Restek Rt-Alumina, 30 m 0,53 mm Carrier gas: He Gas flow:10 ml/min Injected dose: 0.25 µl
Injector temperature: 50C
Temperature of the cooling zone of the injector: 10C
Detector temperature: 300C
Temperature program of the column thermostat: 40C – 5 min, 7C/min, 130C – 5 min. Calibration Standards
Preparation of LPG calibration mixtures (liquid) was carried out by gravimety in constant pressure cylinders (floating piston cylinders, 2 dm3). Every component was added directly from a conventional cylinder to a piston cylinder, except iso-pentane, which was transferred to the piston cylinder with a syringe. In the case of propane (major component) the cylinder was slightly heated during transferring in order to maintain enough vapour pressure. Before and after addition of each component the piston cylinder was weighed accurately on RAYMOR HCE-25G balance against a tare cylinder. After filling the piston cylinders were pressurized with He to 2.0 MPa. Purity analysis of the parent substances was carried out by GC- FID, TCD 1 Primary Reference Standard (PSM) was used for calibration. Composition of calibration standard is shown in the table 1. Table 1
Cylinder N 2316
Component
Amount of sub-stance fraction, cmol/mol
ugrav, cmol/mol (k=1)
Ethane 2,2647 0,0007
Propene 9,1447 0,0005
n-Butane 9,9547 0,0004
1-Butene 3,061 0,0005
i-Butane 4,0289 0,0004
i-Pentane 0,9890 0,0004
Propane 70,5443 0,0009
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Purity data for parent gases is shown ithe tables 2-8 Table 2 - Purity data for ethane
Cylinder N4877
Component Amount fraction
cmol/mol Standard uncertainty (k=1)
cmol/mol
ethane 99,99988 -
n-butane 0,00012 0,00001
Table 3- Purity data for propene
Cylinder N4142
Component Amount fraction
cmol/mol Standard uncertainty (k=1)
cmol/mol
propene 99,97184 —
propane 0,0209 0,0008
nitrogen 0,0070 0,0007
i-butane 0,00026 0,00003
Table 4 - Purity data for n-butane
Cylinder N 3405
Component Amount fraction
cmol/mol
Standard uncertainty (k=1)
cmol/mol
n-butane 99,97095 —
neo-pentane 0,0244 0,0007
i-butane 0,0031 0,0002
trans-2-butene
0,00088 0,00009
cis-2-butene 0,00037 0,00004
propane 0,00030 0,00003
Table 5 - Purity data for 1-butene
Cylinder N 4142
Component Amount fraction
cmol/mol
Standard uncertainty (k=1)
cmol/mol
1-butene 99,4508 —
n-butane 0,243 0,006
i-butene (2-methylpro-pene)
0,124 0,008
i-butane 0,093 0,002
nitrogen 0,059 0,006
trans-2-butene 0,0103 0,0007
oxygen 0,010 0,001
propene 0,0058 0,0002
propane 0,0017 0,0002
29
1,3- butadiene 0,0014 0,0001
cis-2-butene 0,0010 0,0001
Table 6 - Purity data for i-butane
Cylinder N4874
Component Amount fraction
cmol/mol Standard uncertainty (k=1)
cmol/mol
i-butane 99,97725 —
n-butane 0,012 0,001
propane 0,0102 0,0004
i-butene 0,00055 0,00006
Table 7- Purity data for i-pentane
Cylinder N 8027-1
Component Amount fraction
cmol/mol
Standard uncertainty (k=1)
cmol/mol
i-pentane 99,6822 -
n-pentane 0,255 0,015
neo-pentane 0,043 0,004
toluene 0,0072 0,0007
n-heptane 0,0030 0,0003
n-hexane 0,0027 0,0003
1-hexene 0,0016 0,0002
2-methyl-1-butene 0,0016 0,0002
cyclohexane 0,00115 0,00001
1-pentene 0,00057 0,00006
n-butane 0,00051 0,00005
n-nonane 0,00047 0,00005
cyclopentane 0,00029 0,00003
3-methyl-1-butene 0,00020 0,00002
2,2-dimethylbutane 0,00018 0,00002
2-methyl-2-butene 0,00014 0,00001
benzene 0,00012 0,00001
n-octane 0,00010 0,00001
trans-2-pentene 0,00010 0,00001
2-methylpentane 0,00009 0,00001
3-methylpentane 0,000077 0,000008
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Table 8 - Purity data for propane
Cylinder N 3889
Component Amount fraction
cmol/mol
Standard uncertainty (k=1)
cmol/mol
propane 99,9957 —
n-butane 0,0029 0,0001
propene 0,00076 0,00006
ethane 0,00035 0,00004
i-butane 0,00025 0,00003
Instrument Calibration
Single point calibration method was used to determine components mole fraction in the LPG mixture to be investigated (mathematical model – у=ax). Measurement sequence was in the order: Calibration mixture - Comparison mixture - Calibration mixture Analysis results were normalised to 100 %.
Sample Handling
The cylinders had been kept for at least 24 hrs at room temperature (t = (20 ± 2) ºС) before
measurements.
The injection of the sample was carried out by sampling valve for liquefied gases, which enables to maintain single-phase state for mixtures of liquefied hydrocarbons with saturated vapor pressure higher than atmospheric. Pressure in the injection system is provided by pressure in a working chamber of the piston cylinder (2.0 MPa).