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The DATAPROP properties database

The database is a precisely formatted datafile that contains information in a specific order. This data comprises for the most part co-efficients for the various terms in equations used in HGSYSTEM to represent material properties. There are two choices if it is necessary to carry out calculations for a chemical not in the database. Either the database can be extended or a GASDATA file segment can be created and used as a template.

New compounds can be added to the database by appending new datablocks at the end of this file. The added data has to be in order and in the correct format. There is no limit to the number of items that can be added. Unlike Version 3.0, which used a compiled version of the database, the HGSYSTEM V3.1 (and later) programs will read the database file, which is called DATAPROP.DPD, each time they need thermodynamic data. The file DATAPROP.DPD must be in the HGSYSTEM directory. We recommend that a backup copy is made before any additions are made. If the file becomes damaged then a fresh copy can be downloaded from this site.

There are several sources of chemical properties data. Data that is gathered and provided by a service provider may not be able to be freely distributed and, for that reason, only a few compounds are made available by default in HGSYSTEM. Two databases that have the necessary data are DIPPR, available by subscription from the AIChE, and PEPPER which is available to Shell companies only.

Each component in the data base occupies a self contained data block and blocks are separated by a horizontal rule. Each block contains four sets of information:
Component Is a comment and is unused. A long form of the Component name would be a suitable choice. eg Sulphur Dioxide
Component name Alphanumeric, 1 to 12 upper case characters. Duplicate entries are not allowed. e.g. SO2
Aerosol class Is a 2 digit integer. This is used to determine which compounds can mix in the liquid phase. Miscible compounds should have the same Aerosol class number. There are reserved values which have special meaning:
-1 A material which never evaporates.
0 A material which only has a gas phase
1 Used for "special" compounds. These are water and HF.

  • The property data comprise 52 values. Each value has 13 characters comprising 5 significant digits and a 4 character exponent. Example: .22120E+03.
  • These values are stored 5 per line.
  • The following table entries give the record number, a symbolic name for the data item, an explanation of the record purpose and the corresponding formula used to calculate it.
  • WARNING the units used are somewhat idiosyncratic in that they are chosen to match the values returned from the Shell database PEPPER. Thus be careful of the following:
    • J -> kJ
    • mol -> kmol
    • C -> K
1 TC critical temperature (K)
2 PC critical pressure (MPa)
3 VC critical volume (m3/kmol)
4: MOLW molecular weight (g/mol)
5: ATBP boiling point at atmospheric pressure (K)
6,7: CL,CU: lower, upper flammability limits (% volume fraction)
(zero values if not flammable)
8-12: A,B,C,D,E: specific heat of liquid CPL (J/kmol/K)
CPL = A + B*T + C*T 2 + D*T3 + E*T4
T is temperature [K]
13-20: CP1,..,CP8: specific heat of vapour CPV (J/mol/K),
CPV = CP1 + CP2*T + CP3*T2 + CP4*T3 + CP5*T4 + CP6*T5 + CP7*T -1 + CP8*T -2
21-37: TL-273.15,
heat of vaporisation HVAP (kJ/mol) [TR=T/TC]
AL*[(1-TR)BL + CL*(1-TR)6 ] + DL*(1-TR)
AM + BM*TR + CM*TR2 + DM*TR3 + EM*TR4 + FM*TR5
TL < TU < TU
AU*[(1-TR)BU + CU*(1-TR)DU] + EU*(1-TR) T > TU
38-40: A,B,C: liquid density at saturated pressure (kg/m3)
DLIP = A*[1 + B*(1-TR)1/3 + C*(1-TR)]
41-44: B1,B2,B3,B4: saturated real vapour pressure (MPa)
PWAG = PC* EXP{[B1*Q + B2*Q3/2) + B3*Q3 + B4*Q6]/TR}
Q=1-TR, TR = T/TC, Temperatures in K, Pressure in MPa
45-48: A,B,C,D thermal vapour conductivity (J/s/m/K)
LAMBDA = A*TB*(1+C*T -1+D*T -2)
49-52: A,B,C,D: vapour viscosity (Ns/m2)
VISCO = A*TB*(1+C*T -1+D*T -2)

example - properties for chlorine

C======================================================================= chlorine (CL2) CHLORINE 02 .41695E+03 .77920E+01 .12400E+00 .70906E+02 .23910E+03 .00000E+00 .00000E+00 .63936E+05 .46350E+02 -.16230E+00 .00000E+00 .00000E+00 .26781E+02 .22090E-01 .44594E-04 -.18733E-06 .20754E-09 -.76210E-13 .00000E+00 .00000E+00 -.50000E+03 .00000E+00 .00000E+00 .00000E+00 .00000E+00 -.40000E+03 .19426E+02 .33330E+00 .20177E+02 .66670E+00 -.13047E+02 .00000E+00 .00000E+00 .00000E+00 .00000E+00 .00000E+00 .00000E+00 .57185E+03 .18658E+01 .76840E+00 -.57658E+01 -.21531E-01 -.13185E-01 -.41097E+01 .99930E-03 .54720E+00 .45860E+03 .00000E+00 .26000E-06 .74230E+00 .98300E+02 .00000E+00

The GASDATA datablock

As an alternative to extending the database a GASDATA block can be created and saved as a template. The format of the GASDATA block is:
GASDATA     * --------> [pollutant = dry pollutant (aerosol), water]
WATERPOL = .0000 * - water in pollutant (mole fraction)
CPGAS = 33.74 * J/MOLE/C specific heat of dry pollutant
MMGAS = 70.91 * KG/KMOLE molecular mass of dry pollutant
HEATGR = 15.69 * ..... heat group (used for HEGADAS link only)
SPECIES = CHLORINE , 1.00000 , 2
33.7374 , 64.7764 , 19365.5 , 416.950 , 76.9011
-5.76580 ,-2.153100E-02,-1.318500E-02, -4.10970 , 70.9060