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The Measurement of High Pressure Vapour‐Liquid‐Equilibria: Part II: Static Methods
Author(s) -
Raal J. D.,
Mühlbauer A. L.
Publication year - 1994
Publication title -
developments in chemical engineering and mineral processing
Language(s) - English
Resource type - Journals
eISSN - 1932-2143
pISSN - 0969-1855
DOI - 10.1002/apj.5500020202
Subject(s) - homogenization (climate) , sampling (signal processing) , sample (material) , mechanics , chemistry , materials science , thermodynamics , chromatography , optics , physics , biodiversity , ecology , detector , biology
Static equilibrium cells in a variety of configurations have been widely used for high pressure VLE measurement. The method can be divided into analytical procedures where both vapour and liquid compositions are sampled and measured, and the synthetic method for which no sampling of the phases is required. Where the isobars and isotherms have large gradients the synthetic method is the least accurate of the two methods. For mixtures with more than two components the information obtainable by the non‐analytical method is limited. Attempts to combine features of the analytical and non‐analytical method in a single cell are also described. The difficulty of sampling from a high pressure space without serious disturbance of the equilibrium, and the problem of homogenization of a vapourised liquid sample are reviewed. A static jet mixer for vapourized liquid‐sample homogenization is described. A new static equilibrium cell design is proposed in which the liquid level is made visible by internal mechanical adjustment, and multiple liquid‐phases can be sampled using a single sampling valve without disturbing equilibrium. A mechanism for producing a small continuous flow of liquid through a sample valve by use of the internal stirrer is a novel idea, and is also described.