Phase equilibria analysis in two-phase systems requires discernment of the individual phases as well as the interfacial region. The phase behavior of fluids in constraint geometries have been studied through several techniques. High-Field Nuclear Magnetic Resonance (HF-NMR) can be used to detect fluid phases, i.e. gas, liquid, or supercritical fluid, in the bulk or under confinement. In solution-state HF-NMR, each phase exhibits a distinct chemical shift that correlates to the phase density. In turn, the emergence of multimodal in NMR spectra reveals the coexistence of multiple phases in fluid systems. Our results for ethane show that HF-NMR can enable tracking phase changes in the bulk, but also in macro-scale (10–100′s μm in pore size) porous systems at various pressure and temperature conditions, even when the system us out of equilibrium. These results creates potential opportunities to investigate phase changes influenced by confinement in porous systems, though additional steps are necessary.

两相系统中的相平衡分析需要辨别各个相以及界面区域。已经通过多种技术研究了约束几何形状中流体的相行为。高场核磁共振 (HF-NMR) 可用于检测流体相，即气体、液体或超临界流体，在本体中或在限制下。在溶液状态的 HF-NMR 中，每个相都表现出与相密度相关的独特化学位移。反过来，核磁共振光谱中多峰的出现揭示了流体系统中多相的共存。我们对乙烷的研究结果表明，HF-NMR 可以在各种压力和温度条件下跟踪本体中的相变，但也可以在宏观尺度（孔径为 10-100 微米）多孔系统中进行跟踪，即使在系统使用时也是如此的平衡。