Crystalliser for sublimed material with supported spirally-finned tube bundle

摘要

The crystalliser (2) recovers sublimed products on the bundle of finned tubes (4). These penetrate the vessel sides horizontally, and have sectional support. Through their long U-profiles, coolant (KO) flows transversely to the external product-laden gas (RG). Solid product, esp. phthalic anhydride (PSA), deposits on the finned tubes. It is subsequently melted off by heating medium (HO), leaving the basal (11) outlet (12). The novel structure has all open ends of the tubes fixed fluid tight in the same end wall (8), the other ends of the tubes sliding through penetrations in the opposite end wall (25). Interconnecting bends are housed in a cover (28), forming a fluid-tight expansion chamber (26).