Feasibility Study of a Novel Membrane Reactor for Syngas Production. Part 1: Experimental Study of O2 Permeation through Perovskite Membranes under Reducing and Non-Reducing Atmospheres

In this contribution, the feasibility of a novel membrane reactor for energy efficient syngas production is investigated by means of an experimental and a simulation study. In Part 1, a detailed experimental study is performed on the O2 permeation through a perovskite membrane with composition (LaCa)(CoFe)O3−δ for different operating conditions. In these experiments, non-reducing and reducing gasses were used as sweeping gas and also the flow rate, the composition of the sweeping gas, the membrane thickness and the temperature were varied. It was found that the O2 permeation flux was greatly enhanced when sweeping with reducing gasses and also a higher temperature or a thinner membrane resulted in higher O2 permeation rates. For both non-reducing and reducing gasses, the O2 permeation flux was controlled by bulk diffusion and could be described with the Wagner equation. Furthermore, when sweeping with CO or H2, it was found that the local O2 partial pressure, which determines the O2 permeation rate, could be calculated from the local equilibrium constants of the CO and H2 combustion reactions. In Part 2, the derived permeation expressions will be used to study the feasibility of a novel Reverse Flow Catalytic Membrane Reactor concept for energy efficient syngas production.