The topic of air separation is studied for portable power system applications. Air separation is of interest for controlling and optimizing the combustion characteristics in a liquid fuel burner. In particular, polymeric membranes are investigated for their performance in supplying oxygen enriched air to a small burner. The air separation performance of perfluorodioxole polymer membranes is measured, and the relationship between membrane performance and combustion parameters is investigated. The feasibility of using such membranes for burner based power system applications is demonstrated and appears to be promising. The power draw necessary to achieve prescribed flow and performance was measured and found to be relatively low. A dimensionless enrichment number is defined, and a membrane figure of merit is introduced. (C) 2006 Elsevier Ltd. All rights reserved.