Partial oxidation of ethane to syngas in an oxygen-permeable membrane reactor

Abstract

A perovskite-type oxide of Ba 0.5Sr 0.5Co 0.8Fe 0.2O 3− δ (BSCFO) with mixed electronic and oxygen ionic conductivity at high temperatures was used as an oxygen-permeable membrane. A tubular membrane of BSCFO made by extrusion method has been used in the membrane reactor to exclusively transport oxygen for the partial oxidation of ethane (POE) to syngas with catalyst of LiLaNiO/γ-Al 2O 3 at temperatures of 800–900 °C. After only 30 min POE reaction in the membrane reactor, the oxygen permeation flux reached at 8.2 ml cm −2 min −1. After that, the oxygen permeation flux increased slowly and it took 12 h to reach at 11.0 ml cm −2 min −1. SEM and EDS analysis showed that Sr and Ba segregations occurred on the used membrane surface exposed to air while Co slightly enriched on the membrane surface exposed to ethane. The oxygen permeation flux increased with increasing of concentration of C 2H 6, which was attributed to increasing of the driving force resulting from the more reducing conditions produced with an increase of concentration of C 2H 6 in the feed gas. The tubular membrane reactor was successfully operated for POE reaction at 875 °C for more than 100 h without failure, with ethane conversion of ∼100%, CO selectivity of >91% and oxygen permeation fluxes of 10–11 ml cm −2 min −1.