Dense perovskite membrane reactors for partial oxidation of methane to syngas

The partial oxidation of methane to synthesis gas (syngas, CO + H-2) was performed in a mixed-conducting perovskite dense membrane reactor at 850 degrees C, in which oxygen was separated from air and simultaneously fed irate the methane stream. Steady-state oxygen permeation rates for La(1-x)A(x)(')Fe(0.8) Co0.2O3-delta perovskite membranes in nonreacting air/helium experiments were in the order of A'(x) = Ba-0.8 > Ba-0.6 > Ca-0.6 > Sr-0.6. Deep oxidation products were obtained from a La-0.2 Ba-0.8 Fe-0.8 Co-0.2 O3-delta disk-shaped membrane reactor without catalyst, with a 4.6% CH, inlet stream. These products were further reformed to syngas when a downstream catalytic bed was added. Packing the 5% Ni/Al2O3 catalyst directly on the membrane reaction-side surface resulted in a slow fivefold increase in O-2 permeation, and a fourfold increase in CH4 conversion. XRD, EDS, and SEM analyses revealed structure and composition changes on the membrane surfaces. Oxygen continuously transported from the air side appeared to stabilize the membrane interior, and the reactor was operated for up to 850 h.