Water injection as a means for reducing non-condensible andcorrosive gases in steam produced from vapor-dominated reservoirs Page: 3 of 8
This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
Assuming pure water and ideal behavior in the gas
phase, we have y ~ 1, (D ~ 1, so thatK ~ mHCl(aq)/PHCI(g)
HCl, Eq. (10) has for xHC1 << 1 the form of Henry's
law Eq. (3), with Henry's coefficient given by(6)
(11)
K(K 55.5
H K1K1pH)Eq. (6) has the form of Henry's law, with solubility K
being an inverse Henry's coefficient. Aqueous HCl
may dissociate according to
HCaq = H +C- (7)
with a dissociation equilibrium constant of
K, = mH+mCl_/mHCl(aq) (8)
where we again assumed activity coefficients equal to
1, so that molalities may be used instead of activities.
Equilibrium constants for Eqs. (6, 8) for a range of
(T, P)-conditions are given in Table 1, as obtained
from SUPCRT92 (Johnson et al., 1992).
Table 1. Equilibrium constants for reactions Eq. (4,
7) from SUPCRT92 (Johnson et al., 1992).
T ( C) P (bar) log(K) log(K1)
0.01 1.013 6.958 0.513
25 1.013 5.596 0.71
60 1.013 4.083 0.802
100 1.013 2.754 0.748
150 4.757 1.513 0.518
200 15.537 0.605 0.142
250 39.736 -0.044 -0.39
300 85.838 -0.45 -1.169
To proceed further we assume that pH will be
constrained by interactions between the fluids and
assemblages of reactive minerals. For example,
Haizlip and Truesdell (1988) suggested that pH of
aqueous phase at The Geysers may be buffered at
near-neutral values by reactions between feldspars
and micas. Substituting mH+ = 10-pH, Eq. (8) gives
mcl- = KImCI(aq) 10pH (9)
so that total aqueous HCl concentration becomes
mHCl(aq,tot) =mHCl(aq)(1+K1lOPH) and, substituting into
Eq. (6),Thus, under conditions where pH is strictly
constrained by mineral reactions, Henry's law is
applicable to HCl dissolution.
Relationships between PHCI(g) and aqueous HCl
concentration, expressed as mole fraction xHC, are
plotted in Fig. 1. For comparison Fig. 1 also includes
PHC1 for a hypothetical Henry's coefficient of KH = 1
bar, corresponding to a pH = 2.17 according to Eq.
(11). HCl solubilities increase strongly (KH
decreases) with decreasing temperature and
increasing pH (Figs. 2, 3).n
10 -
10~' -
104 -
103 -
10 -
1 0- -
10.7 -
10 -
10-'U
- pH-=0
. - -.- PH= .5
- --10.1
HCI dissolved mole fraction
Figure 1. HCl partial pressures at 250 "C for
different pH. The line labeled KH = 1 bar
refers to a (hypothetical) Henry's
coefficient of 1 bar.0
v
C
210 -
1 -
10'3 -
In -
10- ---- -pH= S
. . . . . . . . . . . . . . . . . .
0 50 100 150 200 250
Temperature ("C)300
1
PHC(g) H K(H+KlOpH)mCl(aq,tot)(10)
Figure 2. Henry's coefficient for HCl dissolution in
pure water under pH-constrained
conditions as function of temperature.Substituting mHCI(aqtot) = 55.5xHC(1- xHCI), with xHCl the
total mole fraction of (associated and dissociated)
Upcoming Pages
Here’s what’s next.
Search Inside
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
Pruess, Karsten; Spycher, Nicolas & Kneafsey, Timothy J. Water injection as a means for reducing non-condensible andcorrosive gases in steam produced from vapor-dominated reservoirs, article, January 8, 2007; Berkeley, California. (https://digital.library.unt.edu/ark:/67531/metadc897779/m1/3/: accessed April 23, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.