DENSE PEROVSKITE MEMBRANE REACTORS FOR PARTIAL OXIDATION OF METHANE TO SYNGAS

The partial oxidation of methane to synthesis gas (syngas, CO + H-2) w as performed in a mixed-conducting perovskite dense membrane reactor a t 850 degrees C, in which oxygen was separated from air and simultaneo usly fed irate the methane stream. Steady-state oxygen permeation rate s for La(1-x)A(x)(')Fe(0.8) Co0.2O3-delta perovskite membranes in nonr eacting air/helium experiments were in the order of A'(x) = Ba-0.8 > B a-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 with out catalyst, with a 4.6% CH, inlet stream. These products were furthe r reformed to syngas when a downstream catalytic bed was added. Packin g the 5% Ni/Al2O3 catalyst directly on the membrane reaction-side surf ace resulted in a slow fivefold increase in O-2 permeation, and a four fold increase in CH4 conversion. XRD, EDS, and SEM analyses revealed s tructure and composition changes on the membrane surfaces. Oxygen cont inuously transported from the air side appeared to stabilize the membr ane interior, and the reactor was operated for up to 850 h.