An oxygen transport membrane (OTM) has been receiving remarkable attention because of its potential to produce high-purity oxygen energy-efficiently and economically comparing with conventional cryogenic air separation system. Recently, KIER reported outstanding oxygen permeation of dual-phase membrane (80% GDC­20% LSCF) with modified surface by LSC. In present study, a two-dimensional numerical study was conducted to estimate the oxygen permeation characteristics affected by its various operating conditions in a preliminary OTM module design step. The planar and counterflow type module design was chosen for effective usage of membrane area and to prevent mass transport limitation. Parametric studies show that the oxygen flux is significantly affected by oxygen partial pressure difference between feed-retentate and permeate streams, air feeding mass and working temperature.