Dual-zone boiling process

摘要

The invention relates to a process and apparatus for boiling flowing liquid such as liquefied gases in a heat exchanger in which a circulating flow is occuring, such as in reboiler-condensers in air separation and similar cryogenic plants or other applications where a high efficiency for boiling heat transfer is beneficial. The important feature of the process and apparatus is the use of two sequential heat transfer zones having different pressure drop and heat transfer characteristics in the same boiling channel, the first zone having a higher pressure drop and high convective heat transfer characteristic and the second zone having a lower pressure drop and an enhanced nucleate boiling heat transfer characteristic.