Preliminary Experimental Study for Cryogenic Distillation Column with Small Inner Diameter, (II)

Abstract

Characteristics of a cryogenic distillation column having a small inner diameter (-2 em) were studied by separating N 2 and Ar for Dixon Ring, Coil Pack, Helix and Heli-Pak. The size of the packings was -1/6 of the inner diameter of the column. The overall HETP value represented no dependence on the vapor flow rate regardless of the packing species used. A tendency common in the four packing species was that the discrepancy between the calculated and experimentally observed Ar concentrations at the middle of the column was enhanced by the decrease in the vapor velocity. This result is ascribed to the phenomenon that the effective vapor/liquid interface area of a portion near the large condenser differs from that near the wire holding the packings. Packings having small void fractions and densely-coiled structure like Coil Pack made this problem more serious. Dixon Ring has an exceptionally large void fraction, nevertheless it presents an adequately large vapor /liquid interface area. In fact, it presented the best set of results of the lower pressure drop, smaller HETP and more readiness in predicting column behavior by the stage model.

Additively manufactured cryogenic microchannel distillation device for air separation

“…The HETP values for the TRP column are consistent with a previous study [ 27 ] that used similar random packing for nitrogen–argon separation. HETP values for the PTL column are lower, while those for the AMPH column are the lowest (3.2 cm for nitrogen, 3.3 cm for argon).…”

Cryogenic distillation facility for isotopic purification of protium and deuterium

“…This type of packing (but bigger size 33 mm 2 ) was earlier tested in Petersburg Nuclear Physics Institute (PNPI) water distillation columns of 80 mm inner diameter and showed good separation characteristic 16 (HETP = 2.5-3 cm). A similar packing made of stainless steel (Heli-Pak and Coil Pack), which was tested in a cryogenic distillation column of small diameter resulted 17 in a HETP value about 5-6 cm. Thus, the HETP value of 5 cm was used in the design as a conservative approach.…”

“…The quantity of hydrogen held on the packing was calculated from the observed liquid level and reboiler geometry, assuming that the liquid film in the condenser is negligible. 17…”