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Abstract

Integrated multi-functional chemical or biochemical reactors have attracted large attention during the last decades due to their interesting operational characteristics, versatility and multi-purpose applicability compared to traditional systems consisting of individual unit operations. The integration of several unit operations and necessary equipment into a single compact unit shortens transport paths, reduces amount of auxiliary media, increases energetic efficiency, reduces amount of wastes produced etc. Here we describe an attempt to integrate the electro-membrane reactor with a fuel cell stack in order to build-up an autonomous (independent of external power source) portable multi-functional unit (MFU). The MFU comprises two sub-units: the first one that generates the electric current (the fuel cell) and the second one that consumes it and simultaneously performs a biotransformation the reactor. The coupling of both sub-units within this kind of MFU is primarily realized by means of the electric current passing through both parts of the system. In our paper we firstly present results of the measurements of the electric behavior of both sub-units: the current voltage curves and the power current characteristic curves of the fuel cell stack under various operating conditions (hydrogen pressure and volumetric flow rate, mode of hydrogen humidification, air flow rate in the cathodes). The current voltage curves and the power characteristic curves of the membrane reactor are also presented using different buffer solutions and various flow rates. The characteristic curves of the fuel cell stack and of the membrane reactor are then compared in order to find appropriate operating regions where both sub-units can be mutually coupled. Residence time distributions in the flow-through compartments of the electro-membrane reactor are also analyzed. An outlook to system design modifications is given based on the conclusions deduced from the experimental results.