One-pot neutron imaging of surface phenomena, swelling and diffusion during methane absorption in ethanol and n-decane under high pressure

We study the gas diffusion in still liquids under gas high pressures. We demonstrate that the pressure-induced gas diffusion, liquid swelling and the liquid surface tension can be measured simultaneously in a one-pot experiment. The measurements are performed using the high-resolution neutron imaging in a non-tactile way. A major advantage of this new method is that the determination of surface tension necessitate no assumptions imposed on the properties of the liquid.

Our pilot investigations focused on methane diffusion into perdeuterated liquid ethanol and perdeuterated n-decane. These are substances directly relevant for topics of production, refining and transportation of natural gas and crude oil. The simultaneous measurement of gas concentration profiles and surface tension may become useful for modelling of processes used in crude oil recovery. This new method may also provide valuable information in other materials, such as liquid metals where ionic and molecular transport properties could be studied comprehensively.