Article ID Journal Published Year Pages File Type
641086 Separation and Purification Technology 2014 10 Pages PDF
Abstract

•Total reflux pressure-efficiency studies at 80% flooding conditions were conducted.•NH3- and SiH4-based systems behavior on spiral-prismatic packings was examined.•Pressure dependence of column separation factor has maximum for both systems.•Separation efficiency behavior depends on change of HETP and phase equilibrium.•Elevated-pressure distillation shows better separation compared to atmospheric one.

The paper deals with the effect of operating conditions on small-scale randomly-packed column separation performance during distillation of high-purity liquefied gases under elevated pressure (up to 25 × 105 Pa). Examination of mass-transfer performance under elevated pressure at a fixed distance from flood has been made for high-performance spiral-prismatic packings of 4 mm and 2 mm nominal size using silane- and ammonia-based test systems. Impact of simultaneously changing pressure, temperature and flow rates (loading kept at 80% of flooding) on the column separation efficiency has been investigated experimentally and by numerical simulation: variations of steady-state column separation factor and the height equivalent to a theoretical plate (HETP) at total reflux conditions are presented and discussed. Observations made demonstrate that overall column separation efficiency shows an extreme behavior – maximum separation effect is achieved under certain temperature (pressure) depending on the variation of the HETP and vapor–liquid equilibrium of the matrix-impurity system. Dependencies obtained are similar both for ammonia- and for silane-based systems and are in agreement with those predicted by analytical method based on empirical correlative approach found in the literature.

Related Topics
Physical Sciences and Engineering Chemical Engineering Filtration and Separation
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