Enhanced heat transfer surfaces

摘要

Aluminum alloys suitable for fabrication into plate and fin type heat exchangers are subjected to a chemical etching procedure in order to improve the heat transfer efficiency thereof. Applicants have found that a high temperature heat treatment of an aluminum alloy plate material to produce a precipitate, followed by exposure to an etching composition, results in a heat exchanger surface modified by the formation of pits. The heat exchangers so modified may be advantageously used in the reboiler/condensor section of air separation units.