Study of hydrogen recovery from Li-Pb using packed tower

Extraction of hydrogen from a Li-Pb flow to inert Ar one using a random packed tower is experimentally investigated for development of a more efficient tritium recovery system of DEMO fusion reactors. A small-scale tower of 57.2 mm in diameter and 300 mm in height packed with SS304 Raschig rings is supplied with two counter-current flows, which one is liquid Li-Pb absorbing hydrogen of 5.06 kPa in equilibrium pressure from the top of the tower and another is Ar gas from the bottom. Overall mass-transfer rates are experimentally determined as a function of Li-Pb flow rates and Ar gas ones at constant temperature of 673 K. Overall mass-transfer capacity coefficients are determined by fitting a transfer equation of hydrogen in a random packed tower to experimental variations of its concentration in gas under given conditions of the space velocity of liquid or gas, and the values of the mass-transfer capacity coefficient increase with Li-Pb flow rates almost linearly. The hydrogen recovery ratios between the top and bottom of the tower were almost independent of the Li-Pb flow rate, and its values were between 20% and 30%.