Open AccessDense ceramic membranes for methane conversion
Author(s) -
U. Balachandràn,
R.L. Mieville,
Beihai Ma,
C.A. Udovich
Publication year - 1996
Language(s) - English
Resource type - Reports
DOI - 10.2172/267578
Subject(s) - syngas , methane , oxidizing agent , ceramic , partial oxidation , membrane reactor , oxygen , ceramic membrane , oxide , partial pressure , materials science , membrane , chemical engineering , electrical resistivity and conductivity , anaerobic oxidation of methane , analytical chemistry (journal) , chemistry , catalysis , composite material , electrical engineering , chromatography , biochemistry , organic chemistry , engineering , metallurgy
This report focuses on a mechanism for oxygen transport through mixed- oxide conductors as used in dense ceramic membrane reactors for the partial oxidation of methane to syngas (CO and H{sub 2}). The in-situ separation of O{sub 2} from air by the membrane reactor saves the costly cryogenic separation step that is required in conventional syngas production. The mixed oxide of choice is SrCo{sub 0.5}FeO{sub x}, which exhibits high oxygen permeability and has been shown in previous studies to possess high stability in both oxidizing and reducing conditions; in addition, it can be readily formed into reactor configurations such as tubes. An understanding of the electrical properties and the defect dynamics in this material is essential and will help us to find the optimal operating conditions for the conversion reactor. In this paper, we discuss the conductivities of the SrFeCo{sub 0.5}O{sub x} system that are dependent on temperature and partial pressure of oxygen. Based on the experimental results, a defect model is proposed to explain the electrical properties of this system. The oxygen permeability of SrFeCo{sub 0.5}O{sub x} is estimated by using conductivity data and is compared with that obtained from methane conversion reaction