Establishing Benchmarks
for the Fourth Industrial Fluid
Properties Simulation Challenge
James D. Olson
The Dow Chemical Company
November 8, 2007
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Overview
The Fourth Challenge
 Three Categories of Benchmarks
Benchmark Data Sources
 Literature and estimations from DIPPR and
PPDS
The 17 Benchmarks and Uncertainties
 Second virial coefficient Benchmark value was
revised
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Acknowledgements – Data Reviewed by:
Dan Friend – NIST
Rob Chirico – NIST (TRC)
Marcia Huber - NIST
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Industrial Fluid Properties Simulation Challenge
Industrial use of molecular simulation:
 Qualitative use vs quantitative chemical use:
Qualitative - explore structure and mechanisms at the
molecular level, pico-sec time scale; e.g., to study
formation and structure of surfactant micelles.
Quantitative - produce process design data for state
conditions not (easily) accessible to lab measurements.
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The Fourth Challenge
The primary objective of the Fourth
Industrial Fluid Properties Simulation
Challenge is to test the transferability of
methods and force fields to a wide variety
of properties for a given small molecule.
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Three Categories of Benchmarks
Category 1 (100 points total)

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





Saturated liquid phase density at 375 K (11 points max)
Saturated vapor phase density at 375 K (11 points max)
Second virial coefficient at 375 K (11 points max)
Vapor pressure at 375 K (11 points max)
Heat of vaporization at 375 K (11 points max)
Normal boiling temperature at 101.325 kPa (15 points max)
Critical density (15 points max)
Critical temperature (15 points max)
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Three Categories of Benchmarks
Category 2 (100 points total)
 Saturated liquid phase heat capacity at 375 K (15 points
max)
 Saturated vapor phase heat capacity at 375 K (15 points
max)
 Saturated liquid phase isothermal compressibility at 375 K
(20 points max)
 Saturated vapor phase isothermal compressibility at 375 K
(20 points max)
 Surface tension at 375 K (30 points max)
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Three Categories of Benchmarks
Category 3 (100 points total)
 Saturated liquid phase viscosity at 375 K (25 points max)
 Saturated vapor phase viscosity at 375 K (25 points max)
 Saturated liquid phase thermal conductivity at 375 K (25
points max)
 Saturated vapor phase thermal conductivity at 375 K (25
points max)
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Benchmark Data Sources
The previous three Challenges used data measured
specifically for the challenge, e.g., liquid viscosity of
2-propanol + nonane mixtures.
No new experimental data were measured for the
Fourth Challenge. Also, for several EO properties no
data have ever been measured above 280 K.
Appropriately larger uncertainties were assigned.
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Benchmark Data Source Strategy
Three data sources were used (similar strategy to that
used in an industrial process design):
 Data published in peer-reviewed scientific literature.
 Data from AICHE DIPPR Database – correlations fitted to
experimental data where available or estimation methods.
 Data from Physical Properties Data Service (PPDS) –
associated with UK NPL
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Max
Benchmark Data - Fourth Challenge IFPSC
Category 1
saturated liquid phase density (g/cm^3)
saturated vapor phase density (g/cm^3)
second virial coefficient (cm^3/g)
vapor pressure (kPa)
heat of vaporization (J/g)
normal boiling temperature at 101.325 kPa (K)
critical density (g/cm^3)
critical temperature (K)
Category 2
saturated liquid phase heat capacity (Cp) (J/g K)
saturated vapor phase heat capacity (Cp) (J/g K)
saturated liquid phase isothermal compressibility
saturated vapor phase isothermal compressibility
surface tension (N/m)
Category 3
saturated liquid phase viscosity (Pa s)
saturated vapor phase viscosity (Pa s)
saturated liquid phase thermal conductivity (W/m
saturated vapor phase thermal conductivity (W/m
1/(10^6 kPa)
1/(10^6 kPa)
K)
K)
Benchmark
Benchmark
Uncertainty
(%)
Allowed
Deviation
(%)
0.744
0.024
-7.59
1437.1
453
283.7
0.314
469.15
0.5
4.1
4.9
1.5
1.8
0.2
5.1
0.2
5.0
20.0
25.0
8.0
10.0
5.0
25.0
5.0
2.30
1.67
2.60
819.00
0.012
8.3
15.0
23.1
9.2
12.5
40.0
50.0
50.0
45.0
50.0
1.51E-04
1.24E-05
0.12
0.0204
13.2
6.5
25.0
14.7
50.0
30.0
50.0
50.0
Benchmark
Benchmark
Uncertainty
(%)
Max
Allowed
Deviation
(%)
0.744
0.024
-7.59
1437.1
453
283.7
0.314
469.15
0.5
4.1
4.9
1.5
1.8
0.2
5.1
0.2
5.0
20.0
25.0
8.0
10.0
5.0
25.0
5.0
2.30
1.67
2.60
819.00
0.012
8.3
15.0
23.1
9.2
12.5
40.0
50.0
50.0
45.0
50.0
1.51E-04
1.24E-05
0.12
0.0204
13.2
6.5
25.0
14.7
50.0
30.0
50.0
50.0
Benchmark Data - Fourth Challenge IFPSC
Category 1
saturated liquid phase density (g/cm^3)
saturated vapor phase density (g/cm^3)
second virial coefficient (cm^3/g)
vapor pressure (kPa)
heat of vaporization (J/g)
normal boiling temperature at 101.325 kPa (K)
critical density (g/cm^3)
critical temperature (K)
Category 2
saturated liquid phase heat capacity (Cp) (J/g K)
saturated vapor phase heat capacity (Cp) (J/g K)
saturated liquid phase isothermal compressibility 1/(10^6 kPa)
saturated vapor phase isothermal compressibility 1/(10^6 kPa)
surface tension (N/m)
Category 3
saturated liquid phase viscosity (Pa s)
saturated vapor phase viscosity (Pa s)
saturated liquid phase thermal conductivity (W/m K)
saturated vapor phase thermal conductivity (W/m K)
Experimental studies that include 375 K
Experimental data only up to 280 K
No experimental data
Maximum Allowed Deviation
vs
Benchmark Uncertainty
Maximum Allowed Deviation (%)
60
50
40
30
20
10
0.0
0.0
5.0
10
15
20
25
Benchmark Uncertainty (%)
30
Second Virial Coefficient at 375 K
Benchmark = -7.59 cm3/g
 Uncertainty = 4.9 %
 Maximum allowed Deviation = 25 %
Benchmark taken as mean between the value derived
from the Walters and Smith PVT data and the value
derived from the Hurly sound speed data.
Benchmark value was revised after discovery of Hurly
sound speed data for ethylene oxide
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2nd Virial Coefficient of Ethylene Oxide
-200
B(cm3/mole)
-300
-400
-500
B derived from Walters and Smith PVT data
NIST - Hurly; B derived from sound speed data
-600
Stryjek data
Revised Benchmark value and uncertainty
-700
300
320
340
360
380
T(K)
400
420
440
Saturated Liquid-Phase Density at 375 K
Benchmark = 0.744 g/cm3
 Uncertainty = 0.5 %
 Maximum allowed Deviation = 5 %
Benchmark taken from DIPPR density
equation fitted to available experimental
data.
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DIPPR Density Equation fitted to EO Density Data
1.00
Benchmark
Density (g/cc)
0.90
0.80
0.70
Density - Experimental Data
0.60
Density - DIPPR Equation 105
0.50
0.40
200
250
300
350
T(K)
400
450
500
Saturated Vapor-Phase Density at 375 K
Benchmark = 0.024 g/cm3
 Uncertainty = 4.1 %
 Maximum allowed Deviation = 20 %
Benchmark calculated from second virial
equation – agrees within uncertainty with
the PPDS value.
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Vapor Pressure at 375 K
Benchmark = 1437 kPa
 Uncertainty = 1.5 %
 Maximum allowed Deviation = 8 %
Benchmark taken from DIPPR vapor
pressure equation fitted to available
experimental data.
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Heat of Vaporization at 375 K
Benchmark = 453 J/g
 Uncertainty = 1.8 %
 Maximum allowed Deviation = 10 %
Benchmark taken from DIPPR heat of
vaporization equation fitted to data derived
from the vapor pressure via the Clapeyron
equation.
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Normal Boiling Point at 101.325 kPa
Benchmark = 283.7 K
 Uncertainty = 0.2 %
 Maximum allowed Deviation = 5 %
Benchmark taken from data of Giauque
and co-workers, J. Amer. Chem. Soc.
(1949) 71, 2176
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Critical Density
Benchmark = 0.314 g/cm3
 Uncertainty = 5.1 %
 Maximum allowed Deviation = 25 %
Benchmark taken from Ambrose &
Townsend, "Vapor-Liquid Critical
Properties“, National Physical Laboratory,
Middlesex, United Kingdom (1977)
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Critical Temperature
Benchmark = 469.15 K
 Uncertainty = 0.2 %
 Maximum allowed Deviation = 5 %
Benchmark taken from Ambrose &
Townsend, “Vapor-Liquid Critical
Properties“, National Physical Laboratory,
Middlesex, United Kingdom (1977)
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Saturated Liquid Heat Capacity at 375 K
Benchmark = 2.30 J/[g-K]
 Uncertainty = 8.3 %
 Maximum allowed Deviation = 40 %
Benchmark taken from an extrapolation of
the measured data of Giauque and
coworkers compared to PPDS and DIPPR
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Saturated Liquid Heat Capacity, J/[g-K]
Ethylene Oxide
Saturated Liquid Heat Capacity, J/[g-K]
2.5
2.4
2.3
DIPPR
PPDS
Experimental Data
Benchmark Extrapolation
2.2
2.1
2.0
1.9
1.8
250
300
350
T(K)
400
Saturated Vapor Heat Capacity at 375 K
Benchmark = 1.67 J/[g-K]
 Uncertainty = 15 %
 Maximum allowed Deviation = 50 %
Benchmark taken from PPDS real gas
correction to ideal gas heat capacity.
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Saturated Liquid Isothermal
Compressibility at 375 K
Benchmark = 2.60 [106 kPa]-1
 Uncertainty = 23.1 %
 Maximum allowed Deviation = 50 %
Benchmark calculated from BrelviO'Connell correlation.
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Saturated Vapor Isothermal
Compressibility at 375 K
Benchmark = 819 [106 kPa]-1
 Uncertainty = 9.2 %
 Maximum allowed Deviation = 45 %
Benchmark calculated from second virial
equation.
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Surface Tension at 375 K
Benchmark = 0.012 N/m
 Uncertainty = 12.5 %
 Maximum allowed Deviation = 50 %
Benchmark taken from DIPPR surface
tension equation fitted to data given by
Jasper.
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Saturated Liquid Viscosity at 375 K
Benchmark = 0.000151 Pa-s
 Uncertainty = 13.2 %
 Maximum allowed Deviation = 50 %
Benchmark taken from DIPPR viscosity
equation fitted to experimental data of
Maass and Boomer.
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Saturated Liquid Viscosity, Pa-s
Ethylene Oxide
0.00060
Saturated Liquid Viscosity, Pa-s
DIPPR
PPDS
Experimental Data
0.00050
Benchmark Extrapolation
0.00040
0.00030
0.00020
0.00010
250
300
T(K)
350
400
Saturated Vapor Viscosity at 375 K
Benchmark = 0.0000124 Pa-s
 Uncertainty = 6.5 %
 Maximum allowed Deviation = 30 %
Benchmark taken from PPDS estimation.
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Saturated Liquid Thermal
Conductivity at 375 K
Benchmark = 0.12 W/[m-K]
 Uncertainty = 25 %
 Maximum allowed Deviation = 50 %
Benchmark taken from DIPPR thermal
conductivity equation fitted to data
estimated by Missenard method (there are
no experimental data at any temperature).
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Saturated Vapor Thermal
Conductivity at 375 K
Benchmark = 0.0204 W/[m-K]
 Uncertainty = 14.7 %
 Maximum allowed Deviation = 50 %
Benchmark taken from DIPPR thermal
conductivity equation fitted to data
measured by Senftleben.
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