Design of cryogenic distillation column for hydrogen isotope separation

Abstract

Cryogenic distillation is preferred to other methods of gas separation at industrial scale because it has the advantage of high separation factors, the possibility to process large amounts of gas while obtaining high purity gases. Similar with the conventional distillation processes, separation by cryogenic distillation is carried out by mass and heat transfer between vapor and liquid phases that flow in countercurrent. The cryogenic distillation column comprises a boiler that produces the necessary amount of vapors along the column, plates or pack-age where the isotopic transfer between the vapors’ and liquid take place and a condenser that provides the liquid reflux along the cryogenic distillation column. In the case of multi-component gas mixtures, determining the transport of the molecular species between the two phases is difficult due to the dependence of the physical-chemical properties of each mixture component. The transport of the molecular species is strongly influenced by the hydrodynamics of the two phases, closely connected with the size of the exchange interface Study and analyses of practical plant performance through computer aided programs has better and cost effective. Aspen Hysys by Aspen Technology is one of the major process simulators that are widely used in cryogenic, chemical and thermodynamic process industries today. In this work, the simulation study of cryogenic air separation unit is performed by using Aspen Hysys. The simulation study is based on both steady state and dynamic (high pressure column and low pressure column)