Numerical study of hydrodynamic behavior of random packing heli-pak in cryogenic distillation column of helium isotope

Abstract The helium isotope separation system based on cryogenic distillation represents a pivotal part in the purification of helium-3 ( 3 He). High specific surface area random packings are often used in packed column for isotope separation. In this study, we designed and simulated a cryogenic distillation column by programming. Numerical simulations of the hydrodynamic behavior of the column filled with heli-pak were then carried out. The liquid holdup and pressure drop for each theoretical stage were modeled using a general packed column model, with predictions based on known packing and fluid properties. In addition, our investigation focused on the impact of the feed flow rates and number of theoretic stages on liquid holdup and 3 He concentration of product. The simulation results show that the pressure drop caused by the heli-pak is negligible and has almost no effect on performance. However, the influence of the liquid holdup is not to be ignored, causing partial storage of 3 He in the column and impairing the yield. And the specified column has a small liquid holdup with high separation performance for a certain feed flow rate and number of theoretic stages.