CHEMP

CHEMP provides data for calculating the thermophysical properties of the NAPL/chemical. The units of many of these constants are not standard metric units, and care must be taken to ensure that the appropriate units are used. Most of the data used in this block can be taken from Appendix A of Reid et al. (1987), where the same units are used as here.

Record CHEMP.1

Free format, or Format(I5)

NumHyC

NumHyC number of organic chemicals for which data are to be entered. NumHyC must be <19.

Record CHEMP.2

Free format, or Format(A20)

HcNames

HcNames name of the organic chemical.

Record CHEMP.3

Free format for 5 parameters, or Format (5E10.4)

TCRITM, PCRITM, ZCRITM, OMEGAM, DIPOLMM

TCRITM chemical critical temperature, K.

PCRITM chemical critical pressure, bar (1 bar = $10^5$ Pa).

ZCRITM chemical critical compressibility.

OMEGAM Pitzer's acentric factor for the chemical.

DIPOLMM chemical dipole moment, debyes.

Record CHEMP.4

Free format for 5 parameters, or Format (5E10.4)

TBOILM, VPAM, VPBM, VPCM, VPDM

TBOILM chemical normal boiling point, K.

VPAM chemical vapor pressure constant from Reid et al. (1987). If VPAM ≠ 0 use Wagner correlation (Reid et al., 1987), for VPAM = 0 use Antoine Correlation.

VPBM chemical vapor pressure constant from Reid et al. (1987).

VPCM chemical vapor pressure constant from Reid et al. (1987).

VPDM chemical vapor pressure constant from Reid et al. (1987).

Record CHEMP.5

Free format for 5 parameters, or Format (5E10.4)

AMWTM, CPAM, CPBM, CPCM, CPDDM

AMWTM chemical molecular weight, g/mole.

CPAM chemical ideal gas heat capacity constant from Reid et al. (1987).

CPBM chemical ideal gas heat capacity constant from Reid et al. (1987)

CPCM chemical ideal gas heat capacity constant from Reid et al. (1987)

CPDDM chemical ideal gas heat capacity constant from Reid et al. (1987)

Record CHEMP.6

Free format for 5 parameters, or Format (5E10.4)

RHOREFM, TDENREF, DIFV0M, TDIFREF, TEXPOM

RHOREFM reference NAPL (liquid) density, kg/m3.

TDENREF reference temperature for NAPL density, K.

DIFV0M reference binary diffusivity of VOC in air, m2/s.

TDIFREF reference temperature for gas diffusivity, K.

TEXPOM exponent for calculation of chemical diffusivity.

Record CHEMP.7

Free format for 5 parameters, or Format (5E10.4)

VLOAM, VLOBM, VLOCM, VLODM, VOLCRITM

Two options are available for calculating the NAPL liquid viscosity. The liquid viscosity constants VLOAM - VLODM for the desired NAPL may be assigned data given in Table 9-8 of Reid et al. (1987), and the viscosity will be calculated using a polynomial fit to actual viscosity data (Eq. 4.3.11 in TMVOC user manual). Alternatively, VLOAM and VLOBM may be set equal to 0, and VLOCM and VLODM are assigned equal to a reference viscosity and a reference temperature, respectively. In this case, the viscosity is calculated from a more general (and less accurate) empirical correlation (Van Velzen et al., 1972).

VLOAM liquid NAPL viscosity constant from Reid et al. (1987).

VLOBM liquid NAPI viscosity constant from Reid et al. (1987).

VLOCM liquid NAPL viscosity constant from Reid et al. (1987). If VLOAM and VLOBM = 0, VLOCM is reference NAPL viscosity in units of cP (1 cP = 10-3 Pa-s).

VLODM liquid NAPL viscosity constant from Reid et al. (1987). If VLOAM and VLOBM = 0, VLODM is reference temperature for NAPL viscosity in units of Kelvin.

VOLCRITM chemical critical volume, cm3/mole.

Record CHEMP.8

Free format for 4 parameters, or Format (4E10.4)

SOLAM, SOLBM, SOLCM, SOLDM

The chemical solubility is calculated from the polynomial SOLUBILITY = SOLAM + SOLBM*T + SOLCM* $T^2$+ SOLDM* $T^3$. If data for the solubility as a function of temperature are available, then SOLAM, SOLBM, SOLCM, and SOLDM should be calculated from a polynomial fit of the data. If such data are not available (the usual case), the solubility will be assumed to be constant, and SOLAM should be set equal to the known solubility, with SOLBM, SOLCM, and SOLDM set equal to 0.

SOLAM constant for chemical solubility in water, mole fraction.

SOLBM constant for chemical solubility in water, mole fraction/$K$.

SOLCM constant for chemical solubility in water, mole fraction/$K^2$.

SOLDM constant for chemical solubility in water, mole fraction/$K^3$.

Record CHEMP.9

Free format for 3 parameters, or Format (3E10.4)

OCKM, FOXM, ALAMM

OCKM chemical organic carbon partition coefficient Koc (see Eq. 4.4.2 in TMVOC user manual), m3/kg.

FOCM default value for fraction of organic carbon in soil, used for all domains for which no specific value is provided in record ROCKS.1.1.

ALAMM decay constant for biodegradation of VOC, s-1. Biodegradation is assumed to take place only in the aqueous phase, and to follow a first order decay law, MVOC(t) = MVOC,0 * exp (-λ t). The decay constant λ = ALAMM is expressed in terms of the half life T1/2 of the VOC as follows: λ = (ln 2) / T1/2. Default is ALAMM = 0.

Repeat records CHEMP.2 through CHEMP.9 for a total of NumHyC (up to eighteen) different organic chemicals.

Used in: TMVOC

EXAMPLE:

CHEMP

2 //Number of organic chemicals

BENZENE // Name of the first chemical

562.2, 48.2, 0.271, 0.212, 0.0 //CHEMP.3 for BENZENE

353.2, -6.98273, 1.33213, -2.62863, -3.33399 //CHEMP.4 for BENZENE

78.114, -.3392E+02, 0.4739E+00, -.3017E-03, 0.7130E-07 //CHEMP.5 for BENZENE

885., 289.00, 0.770E-05, 273.10, 1.52 //CHEMP.6 for BENZENE

0.4612E+01, 0.1489E+03, -.2544E-01, 0.2222E-04, 259.0 //CHEMP.7 for BENZENE

0.411E-03, 0.000E+00, 0.000E+00, 0.000E+00 //CHEMP.8 for BENZENE

0.891E-01, 0.001, 0.0 //CHEMP.9 for BENZENE

n-DECANE // Name of the second chemical

617.700, 21.200, 0.249, 0.489, 0.00 //CHEMP.4 for n-DECANE

447.300, -8.56523, 1.97756, -5.81971, -0.29982 //CHEMP.4 for n-DECANE

142.286, -7.913E+0, 9.609E-1, -5.288E-4, 1.131E-7 //CHEMP.5 for n-DECANE

730.000, 293.000, 1.000E-5, 293.000, 1.600 //CHEMP.6 for n-DECANE

0.0, 0.0, 0.5900, 293.000, 603.000 //CHEMP.7 for n-DECANE

3.799e-7 //CHEMP.8 for n-DECANE, constant solubility

0.000 //CHEMP.9 for n-DECANE. The first parameter is 0.0, others set to default values.