Removal of caprolactam and oligomers thereof from nylon granules containing same

摘要

Caprolactam and oligomers thereof are removed from nylon granules containing same in a process wherein (a) nylon granules are introduced at not less than 100 DEG C. at the top of a substantially upright treatment zone, (b) nylon granules are passed downward through the treatment zone while being heated to from 130 DEG to 210 DEG C., (c) superheated steam is passed at from 130 DEG to 210 DEG C. upward through the treatment zone, (d) dry nylon granules are withdrawn at the bottom end of the treatment zone and steam containing caprolactam and oligomers thereof is withdrawn at the top of the treatment zone, (e) the caprolactam and oligomers thereof containing steam thus obtained is passed through a column giving an aqueous solution of caprolactam and oligomers thereof as bottom product and virtually caprolactam-free steam as overhead product.