T (R) : Henry’s law constant reference temperature (K)
k H R
ð Þ : Henry’s law constant at the reference temperature (atmÁm
3 Ámol
À1
)
R c : gas constant (¼ 1.9872 calÁmol
À1
ÁK
À1 )
R: gas constant (¼ 8.205 Â 10
À5 atmÁm
3 Ámol
À1 ÁK
À1 )
Heron et al. (1998) reported that the Henry’s law constant for TCE increases by a
factor of 20 (from 0.2 to 4) when the temperature varies from 10 to 95
C (Heron
et al. 1998). Figure 3.7 shows how the Henry’s law constant for TCE varies as a
function of temperature.
Table 3.4 Selected NAPL compounds and steam co-distillation boiling points (Lupis 1983;
Unified Facilities Criteria 2006)
NAPL mixture
Component boiling points
(
C)
Co-distillation point (
C) (eutectic
point)
Benzene
80.1
69.4
Water
100
Carbon tetrachloride 76.8
66.8
Water
100
Chlorobenzene
132
56.3
Water
100
Chloroform
61.2
56.3
Water
100
1,2-Dichloroethane
83.5
72.0
Water
100
Dichloromethane
40.1
<39.9
Water
100
1,4-Dioxane
101.3
87.8
Water
100
Ethylbenzene
136.2
92.0
Water
100
Hexane
69.0
61.6
Water
100
Styrene
145.2
93.9
Water
100
Tetrachloroethene
121
88.5
Water
100
Toluene
110.6
85.0
Water
100
1,1,2Trichloroethane
113.7
86.0
Water
100
Trichloroethene
87.1
73.1
Water
100
Xylene
139.1
94.5
Water
100
3 In Situ Thermal Treatments and Enhancements: Theory and Case Study
161