NMR Characterization of unfrozen brine vein distribution and structure in model packed beds

When a brine mixed with particles is frozen, some liquid water persists due to the freezing point depression caused by solute impurity, surface energy, and disjoining pressure (wetting forces). This unfrozen forms complex “liquid vein network” (LVN). However, details of process are still not fully understood, including permeability/tortuosity LVN, content at given temperature. Here, we have applied nuclear magnetic resonance (NMR) relaxation, self-diffusion measurements imaging (MRI) investigate distribution structure LVNs. Magnesium chloride (MgCl2) salt concentrations 15, 30, 60 mM were investigated without poly-methyl methacrylate (PMMA) diameter 0.4, 9.9, 102.2 μm, allowing us quantify LVN as function temperature, MgCl2 concentration, PMMA particle size. The results confirm that inhibition ice recrystallization To gain information on structure, compared NMR Monte Carlo simulations in brine-particle systems. Comparisons between laboratory simulation data suggest that, for our experimental range temperature (−17.4 °C −0.9 ± 0.5 °C), solutes make dominant contribution fraction sizes larger than few microns, whereas finest grained porous media tested, controlled primarily films wet particle-ice interfaces.