Pure component data
Introduction
Although the primary purpose of Multiflash is to calculate the thermodynamic properties of mixtures there may be occasions when you simply want to know the properties of a pure component, particularly those from a particular data source. This is quite simple.
Physical properties of a pure component
If you want the physical properties of a pure component, for example octane, over a range of temperatures you must either:
- Define the problem in Multiflash
- Load an existing problem setup file into Multiflash
- Edit an existing problem setup file and load it into Multiflash
- Write a new problem setup file and load it into Multiflash
If you want to know the stored values for the temperature independent properties or the correlation coefficients of a temperature dependent property you must choose Pure Component Data from the Tools option from the menu bar
Defining the problem interactively
Having successfully loaded Multiflash, choose a suitable model for the problem. If you wish to obtain the properties from the data source correlations then you must use the ideal gas and ideal solution models. This is the Ideal Mixing model set. With this option all properties will be taken from the databank correlations except liquid Cp which is calculated from the vapour phase model and the enthalpy of vaporisation. (If any other model set is defined then only the pure component properties needed for that model set will be taken from the bank. Other properties will be calculated using the model set definitions which include models for the transport properties).
To specify the Ideal Mixing model set:
Select Select from the menu, then
Select Model set, followed by
Selecting Ideal Mixing from the Activity Model selection. Choose the gas phase model as Perfect gas. The recommended and default model for transport properties for the Ideal model is Mixing rules. If you wish to calculate the diffusion coefficient remember to check the box for this to be included in the Model set.
You will see a message to say that the Ideal Mixing model set has been successfully defined.
Click on OK
Specify the pure component of interest in this case octane
Click on the Select Component button
,
or
Select Select then Select Component from the menu bar.then specify the data source and component in the Select Components dialogue box
The data source is set by:
Clicking on the arrow to the right of the data source text box and
Clicking on the data source of interest, in this case INFODATA, the Infochem Fluids databank
The component is specified by either:
Selecting the Name option button, typing the component name in the enter name box, then pressing the enter key or clicking on Add
Selecting the All components button, scrolling through the list of components which will appear in the dialogue box and either selecting octane, then clicking on Add or Double clicking on octane.
or
Selecting the formula option button, typing C8H18 in the text box, clicking on Search, selecting octane in the “Components in databank” text box, then clicking on Add or double clicking on octane
Specifying the physical property output level.
If you are interested in pure component data you will probably want to output all available physical property data except thermal property data relative to elements.
Select Select in the menu bar and then select Property output.
In the resulting dialogue box, the first two are the default options for output of thermodynamic data, click Heat capacity/Speed of Sound and the set of transport property data and finally click on OK.
Enter the composition for the stream.
In this case where we have a pure component the composition is not important provided it is a positive value. The input is summarised in file octane.mfl.
In the main window, click on composition, then type 1.0 in the right-hand column of the table next to octane.
To obtain the properties of liquid octane on the saturation line you must carry out a bubble point flash calculation at a specified temperature.
Specify the temperature and the flash calculation
Type the first temperature, say 250K, in the text box next to temperature in the input conditions section
Click on the Bubble point at fixed temperature button
, or select Calculate from the menu bar, then select Bubble and Dew point flashes and finally select T, Bubble point flash.
Bubble point at fixed T:
T (K ) = 250.000 P (Pa ) = 60.6560
NO. PHASES = 2 CONVERGED STABLE
COMPONENT OVERALL PHASE1 PHASE2
GAS LIQUID1
fractions fractions fractions
OCTANE 1.00000 1.00000 1.00000
Total(mole ) 1.00000 0.00000 1.00000
Z (Fug. Model) 4.569595E-06 1.00000 4.569595E-06
Av.Mol.Wt. 114.231 114.231 114.231
Den/V(m3/mol ) 1.565942E-04 34.2687 1.565942E-04
H ( J/mol ) -52615.9 -8475.15 -52615.9
S ( J/mol/K ) -145.909 30.6542 -145.909
U ( J/mol ) -52615.9 -10553.7 -52615.9
G ( J/mol ) -16138.7 -16138.7 -16138.7
Cp (J/mol/K ) 215.390 163.190 215.390
Cv (J/mol/K ) 215.390 154.875 215.390
Sp.Sound (m/s) 138.468
Visc.(Pas ) 4.323388E-06 1.049643E-03
Th.C.(W/m/K ) 9.535970E-03 0.141892
STen (N/m ) 2.588663E-02
COMPONENT OVERALL PHASE1 PHASE2
GAS LIQUID1
fug. coeff. fug. coeff.
OCTANE 1.00000 1.00000
COMPONENT OVERALL PHASE1 PHASE2
GAS LIQUID1
act. coeff. act. coeff.
OCTANE 1.00000 1.00000
PHASE1
GAS
Diffusion coefficient (m2/s )
OCTANE
OCTANE 2.838187E-03
PHASE2
LIQUID1
Diffusion coefficient (m2/s )
OCTANE
OCTANE 1.065395E-09
The reported pressure is the saturated vapour pressure at 250K, the other properties are listed below the phase equilibrium output. As we are dealing with a pure component exactly the same results would be obtained if we had specified a dew point flash at the same temperature.
The next temperature should be entered in the text box in the Conditions section and the bubble point flash repeated at this temperature.
Producing a problem setup file
You can carry out the same calculation, or series of calculations using a problem setup file. We hope that the commands used are self explanatory. (Simply edit this file if you wish to obtain pure component data for another compound or properties at a different temperature). You can also overwrite the default choice of data source.
To write a problem setup file yourself, use the file shown as an example or save the problem you have specified interactively.
Obtaining properties from Pure component Data option
Although the standard output from Multiflash does not contain any of the constant properties, or indeed the correlation coefficients for the temperature dependent properties, it is possible to obtain these.
Select the components you are interested in, for example octane, as described above. Select Tools from the menu bar, followed by selecting Pure Component data, the following dialogue box will then be activated.
As we are dealing with a single component this will be the only choice available so making sure it is highlighted. Select a property in the list of Select property, click on Edit to view or change the property. You can also print the properties in the results window by clicking Write to Output. This output can then can be saved or copied into other files.
show components "OCTANE" data ;
1 OCTANE
MW 114.231 g/mol
TCRIT 569.32 K
PCRIT 2497000. Pa
VCRIT 0.0004862963 m3/mol
ACENTRICFACTOR 0.396
TBOIL 398.82 K
HFORMATION -208446.9 J/mol
SSTANDARD 466.7252 J/mol/K
TMELT 216.37 K
HMELT 20740. J/mol
SMELT J/mol/K
CPMELT 50.00791 J/mol/K
VMELT 1.967943E-5 m3/mol
RUNIQUAC 5.8486
QUNIQUAC 4.936
THLWATER K
VHLWATER m3/mol
DIPOLEMOMENT 0. debye
PARACHOR 351.4 (dy cm-1)1/4 cm3/mol)
RADGYR 4.6804E-10 m
HOCASS 0.
GFORMATION 16000. J/mol
SFORMATION -752.7986 J/mol/K
TTRIPLE 216.38 K
PTRIPLE 2.1083 Pa
HCOMBUSTION -5074150. J/mol
V25 0.000163374 m3/mol
SOLUPAR 15447.5 (J/m3)1/2
SOLIDSOLUPAR (J/m3)1/2
ZCRIT 0.2587676
REFRACTINDEX 1.39505
TFLASH 286. K
TAUTO 479. K
FLAMLOWER 0.8 vol %
FLAMUPPER 6.5 vol %
SG 0.7066211
EXPANSIVITY 1/K
OMASCALE
OMBSCALE
CNUMBER
REFVISCOSITY Pas
LJEVISC J/K
LJBVISC m
EOSC
TYPE 1.
HDATUM 1.
SDATUM 1.
COMPREFNO 93.
MCRKS1
MCRKS2
MCRKS3
MCPR1
MCPR2
MCPR3
HYDOC
HYD1
HYD2
HYD3
ASSBETA
ASSEPSILON J/mol
ASSGAMMA
ASSDELTA 1/K
ASSFF
ASSAC J m3/(mol)2
ASSBC m3/mol
ASSKAPPA
SAFTKAPPA
SAFTEPSILON K
SAFTGAMMA
SAFTFF
SAFTEK 242.78 K
SAFTSIGMA 3.8373E-10 m
SAFTLAMBDA
SAFTM 3.8176
VSRKS1 m3/mol
VSRKS2 m3/mol/K
VSRKS3 m3 K/mol
VSPR1 m3/mol
VSPR2 m3/mol/K
VSPR3 m3 K/mol
CPIDEAL 1. -32383.514 -3721.3925 4.
76. 290. -1.3945 5.6329999
-5.7709999 0. 0. 10000.
CPSOLID 5. -24. 1.9471999 -.0085359998
1.34E-5 2.094E-8 20. 216.37
PSAT 3. -7.9121099 1.38007 -3.8043499
-4.50132 260. 568.95
HVAP 1. 54909.031 0.3775 0.
0. 0. 0. 568.381
LDENS 1. 2032.52 5407.5898 0.375
0. 568.381
LVISC 2. -20.462999 1497.4 1.3789999
0. 0. 216.38 398.83
VVISC 1. 3.1191E-8 0.92925 55.091999
0. 216.38 1000.
LTHCOND 5. 0.2156 -0.00029483 0.
0. 0. 216.38 398.83
VTHCOND 1. -8758. 0.8448 -2.7121E+10
0. 339. 1000.
STENSION 1. 0.052788999 1.2323 0.
0. 0. 216.38 568.7
CPLIQUID 5. 224.83 -0.18663 .00095890998
0. 0. 216.38 460.
SDENS 5. 8340.9004 -3.1515 0.
0. 0. 133.15 216.38
VIRIALCOEFF 1. .00027389999 -0.00056522 -0.00036335
-1.161662E-5 2.587961E-6 284.38 1500.
DIELECTRIC
CARNUMBER 000111-65-9
FORMULA C8H18
FAMILYCODE AA
UNIFAC CH3 2.0000 CH2 6.0000
The output includes the pure component constant properties and the coefficients for the temperature dependent property correlations. The definitions of the pure component correlations are given in the Models and Physical Properties manual and the Multiflash Programmers Guide.
Excel Interface
The current version of Multiflash does not include options for tabular output or for producing graphical output for properties other than phase boundaries. If this is important to you then we would recommend our Excel interface. For example, the ideal.mfc file with the components set to octane was used in conjunction with this interface and Excel to produce the following output for octane.
Liquid properties on the saturation line
| TEMP | PRESSURE | Cp | ENTHALPY | DENSITY | VISCOSITY | THCOND | SURTEN |
|---|---|---|---|---|---|---|---|
| K | Pa | J/mol/K | J/mol | mol/m3 | Pa.s | W/m/K | N/m |
| 275 | 427.762 | 231.509 | -47030.36 | 6254.853 | 0.000694456 | 0.129901386 | 0.023412311 |
| 300 | 2038.060 | 248.028 | -41036.94 | 6116.615 | 0.000497383 | 0.123463157 | 0.020986387 |
| 325 | 7232.427 | 265.122 | -34623.39 | 5970.103 | 0.000378339 | 0.117296964 | 0.01861228 |
| 350 | 20571.971 | 283.036 | -27771.99 | 5813.892 | 0.000301535 | 0.111402808 | 0.016294025 |
| 375 | 49413.703 | 302.105 | -20457.69 | 5646.112 | 0.000249338 | 0.105780689 | 0.014036467 |
| 400 | 104100.875 | 322.809 | -12645.50 | 5464.231 | 0.000212348 | 0.100430606 | 0.01184554 |
| 425 | 197831.473 | 345.907 | -4285.97 | 5264.678 | 0.000183867 | 0.09535256 | 0.009728721 |
| 450 | 346415.385 | 372.738 | 4694.13 | 5042.146 | 0.000160522 | 0.09054655 | 0.007695758 |
| 475 | 568184.088 | 405.943 | 14411.64 | 4788.154 | 0.000141175 | 0.086012576 | 0.005759993 |
| 500 | 884336.745 | 451.543 | 25074.63 | 4487.608 | 0.00012498 | 0.081750639 | 0.003941011 |
Ideal gas properties at 0.001Pa
| TEMP | Cp | ENTHALPY | DENSITY | VISCOSITY | THCOND |
|---|---|---|---|---|---|
| K | J/mol/K | J/mol | mol/m3 | Pa.s | W/m/K |
| 275 | 176.5271 | -4228.47 | 4.37357E-07 | 4.80261E-06 | 0.01079245 |
| 300 | 189.7323 | 350.1064 | 4.0091E-07 | 5.28049E-06 | 0.01224049 |
| 325 | 202.7498 | 5256.578 | 3.70071E-07 | 5.75694E-06 | 0.01393734 |
| 350 | 215.5304 | 10485.62 | 3.43637E-07 | 6.23188E-06 | 0.01593661 |
| 375 | 228.0325 | 16030.77 | 3.20728E-07 | 6.70529E-06 | 0.01809973 |
| 400 | 240.223 | 21884.65 | 3.00683E-07 | 7.17719E-06 | 0.02038823 |
| 425 | 252.0771 | 28039.12 | 2.82996E-07 | 7.64758E-06 | 0.02280085 |
| 450 | 263.5769 | 34485.55 | 2.67274E-07 | 8.1165E-06 | 0.02533644 |
| 475 | 274.711 | 41214.92 | 2.53207E-07 | 8.58399E-06 | 0.02799391 |
| 500 | 285.4733 | 48218 | 2.40546E-07 | 9.05008E-06 | 0.03077224 |
It is then easy to plot individual properties as a function of temperature or to compare property values from different data sources.