On the design of cascades of ECPrOx reactors for deep CO removal from reformate gas

A strategy for the design of a cascade of electrochemical membrane reactors for the preferential oxidation of carbon monoxide from reformate gases is proposed. Based on the analysis of the system's degrees of freedom of a compact model, an optimisation problem is formulated, using an economic objective function. Two different options are analysed and compared. In the first option, the stages of the cascade are arranged in a single stack. This is a technically preferable option, but it imposes several constraints regarding the size and the current densities of the cascade's stages. We show how the solution of the corresponding optimisation problem can be obtained graphically. The second option neglects the constraints of the first option, but is disadvantageous from a technical point of view. Optimisation results for this unconstrained system show that its objective function values are only marginally better compared to the stacked system. Thus the stacked design can be considered preferable.

► The electrochemical preferential oxidation (ECPrOx) has been studied as a process for deep CO removal from reformate gas. ► Galvanostatic conditions the ECPrOx reactor exhibit oscillatory deeds, which is beneficial to overall efficiency of system. ► A strategy for the design of a cascade of ECPrOx reactors is proposed. ► A corresponding optimisation problem is formulated, using an economic objective function. ► The solution of the corresponding optimisation problem can be obtained graphically and is discussed in detail.