webmaster Posted November 9, 2004 Share Posted November 9, 2004 From: Michael Lim Subject: density of evaporated seawater Could anyone please help me with finding a table containing details of partial Molal Volume of the various salt find in common seawater? From: Michael Lim Subject: density of evaporated seawater The reason why I asked all these questions started with our calculation using seawater as our benchmark. The seawater Specific Gravity reported by Modelling Halite Formation and Brine Densities: Comparison of Non-Marine and Seawater Brines L.A. Chambers, M.W. Wadsley and G.J. Brereton Seventh Symposium on Salts Vol I, 533-538 (1993) was 1.23 (figure 5) at the point when Halite precipitates. But using the same set of inputs and crunched through Geochemists Workbench, we got 1.177. The ionic strength is the same in both cases, 7.266. Just wonder anyone has any idea what I have done wrong. Your help is much appreciated. Please see our input below. h-m-w TDS 35080 swap CO2(g) for H+ log f CO2(g) = -3.5 Cl- = 19350 mg/kg Ca++ = 411 mg/kg Mg++ = 1290 mg/kg Na+ = 10760 mg/kg K+ = 399 mg/kg SO4-- = 2710 mg/kg HCO3- = 142 mg/kg fix fugacity of CO2(g) react -996 grams of H2O From: Craig Bethke Subject: Re: density of evaporated seawater Fluid density as reported by React is what we call a â€œsecondary variableâ€?, i.e., one not used internally in the calculations, but reported for the user's convenience. The calculation method is described by Phillips et al. (1981): Phillips, S. L., A. Igbene, J. A. Fair and H. Ozbek, 1981, A technical databook for geothermal energy utilization. Lawrence Berkeley Laboratory Report LBL-12810, 46 p. The method is a correlation function that gives the density of a NaCl solution from temperature and concentration. (For more info and a corrected coefficient, see the Basin2 Users' Guide, available for download from our web site.) Of necessity, React must treat the general case. But in working with a specific solution (e.g., evaporated seawater) or at a known temperature, it is sometimes possible to calculate density more precisely. Since the reference you cite considers just such a specific case, it likely gives a better estimate of fluid density than the Phillips et al. correlation. My guess is that this is the source of the discrepancy you cite. Quote Link to comment Share on other sites More sharing options...
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