Interfacial tension between water and non‐polar fluids up to 473 K and 2800 bar

Abstract

The method of the Pendant Drop or Standing Bubble is applied to measure interfacial tensions between water and nonpolar fluids to high temperatures and pressures. The high pressure cell with two sapphire windows and the auxiliary equipment with several feed autoclaves is described. The shapes and sizes (about 2 mm) of drops and bubbles are recorded with microscope and video camera. A digital image processing procedure was developed which permits fast, objective and precise determination of the contour parameters.The six gases helium, neon, argon, nitrogen, methane, and propane have been investigated to 473 K (with nitrogen to 573 K) and (in part) to 2800 bar. Gas densities came close to liquid density values. For comparison, water plus liquid n-hexane, n-decane, and toluene was investigated to 473 K and 3000 bar. For these liquid hydrocarbons, the interfacial tension y always increases with pressure. At 373 K for water-n-hexane y is 41.8 mN/m at 100 bar and 47.3 mN/m at 2600 bar, respectively. In the water-gas systems y decreases with pressure and passes through a flat minimum around 1000 bar. For water-nitrogen at 373 K y = 52.5,46.5 and 48.3 mN/m at 200, 1400 and 2800 bar. Only with water-helium y increases continuously with pressure.

Interfacial tensions of the (CO 2 + N 2 + H 2 O) system at temperatures of (298 to 448) K and pressures up to 40 MPa

“…The interfacial tension data are compared with the density-corrected measurements of Wiegand and Franck [7], Tian et al [9] and Yan et al [8] under overlapping p-T conditions, and the agreement is within 3.0 mN·m…”

“…Wiegand and Franck [7] measured the IFT of water and various non-polar fluids including nitrogen, from pressures of (c.a. 20 to 280) MPa, at temperatures of (298 to 573) K. Lower pressure points are only available at T = 298 K, creating difficulty at higher temperatures in extrapolating back to compare with the surface tension of water [27].…”

Interfacial tensions of systems comprising water, carbon dioxide and diluent gases at high pressures: Experimental measurements and modelling with SAFT-VR Mie and square-gradient theory

“…Far fewer studies have been published on the other binary systems of interest in our current paper [68][69][70][71]. The interfacial tension of the (N 2 + H 2 O) system has been measured by Wiegand and Franck [69], Tian et al [70], Yan et al [71] and by Chow et al [68]. The interfacial tension of the (Ar + H 2 O) system has been measured only by Wiegand and Franck [69], who studied just three isotherms.…”

“…Recently, Chow et al [68] reassessed the data measured by Georgiadis et al [65] and Li et al [66,67] to incorporate improved estimates of the density difference accounting accurately for CO 2 dissolution in the aqueous phase and, in the present work, we make use of these revised results. Far fewer studies have been published on the other binary systems of interest in our current paper [68][69][70][71]. The interfacial tension of the (N 2 + H 2 O) system has been measured by Wiegand and Franck [69], Tian et al [70], Yan et al [71] and by Chow et al [68].…”

“…In relation to the systems of interest in this paper, a number of experimental studies have been reported and, in Table 2, we summarise the literature data that are considered further in this article [65][66][67][68][69][70][71]. In fact, numerous workers have measured the interfacial tension of the (CO 2 + H 2 O) system [65,[72][73][74][75][76][77][78][79][80][81][82][83][84][85].…”