To provide an oxygen enriched combustion or partial oxidation process in which air is fed into a ceramic film module under near atmospheric pressure and power demand is substantially lower as compared with current practice.

A flow of matter 232 containing oxygen of relatively high concentration is preheated at a suitable temperature of 500-1000°C, introduced to the holding side 220a of an ion conducting film 220, and passed through the transmitting side 220b before entering into a transmitted matter chamber 238 coupled with a furnace 230. The majority of flue gas generated in the furnace 230 is recirculated as a recirculation flow 246 to the transmitted matter chamber 238. The recirculation flow 246 decreases oxygen concentration on the transmitting side 220b of the ion conducting film 220 and increases oxygen flow passing through the ion conducting film 220.